(2) Chattanooga Shale at Google Indexer on July 12, 2021 Downloaded From

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(x) Kap Frankl~ granlte Devonian/Devonian Kejser Franz Joseph Fjord, East Greenland [73 ° 15' N, 22 ° Io' w]. Radiometric age K-Ar (/l/~ = 4"72 × IO-l°year-1; 2e = 0"583 × Io-X°year-1) KF-XtI, t80, I82 (biotite and muscovite): K = 7-87%, a°Ar* = I "37 × xo-4cma/g, 4°Ar*/4°K = [o'o255], age: 393m.y. Age: 393 4- 12m.y. (3% error in Haller& Kulp i962); 393 4- xom.y. (Kulp I96X ).

Stratigraphical age. The granite intrudes the Vilddal Series (Middle Devonian) and is unconformably covered by the unfossiliferous Kap Franklin Series, which itself is followed by the Randb61 Series (Middle Devonian). The granite is one of a series of'late Caledonian' intrusive rocks of which a pegmatite elsewhere (HN-7b , not stratigraphically related), was dated as 394m.y.; (adopted age = 395 -4- xom.y.). The 'main Caledonian' orogeny, based on five scattered samples of metamorphic rocks, was given as 42o to 4oom.y. The end of the main orogeny from one sample was 4o5 4- xom.y.

Refgt'~e$ BOTLER, H. I954. Die stratigraphische Gleiderung der mitteldevonischen Serien im Gebiet von Kap Franklin am Kejser Franz Joseph Fjord in Zentral-Ostgr6nland. Medd. GrBnland, xx6 (7), x-122. HALtmR, J. & KUTP, J. L. x962. Absolute age determinations in East Greenland. Medd. Grenland, xTx (x), x-77. KULP, J. L, x96 x. [W. B. Harland & A. G. Smith]

Stratigraphical comment. The ages of the two limiting fossiliferous formations within the Givetian are indistinguishable on vertebrate evidence. The most recent statement of the faunas was by Jarvik (x96x). The pre-intrusion Vilddal Series is probably Givetian on the evidence of Gyro- ptychius cf. grgnlandicus. The post-intrusion RandbS1 Series is Lower Givefian on the evidence of Asterolepis cf. sKves6derberghi and Coccosteus el. halmodeus; whereas cf. Thursius macrolepidotus suggests a correlation with the Wick Flagstone Group of Scotland, which WestoU (195 I) regarded as high Eifelian.

R~fgrgl~g$ JnaviK, E. I96I. Greenland Devonian vertebrates. In Geology of the Arctic. (ed. Raasch, G. O.) x, I97-2o 4. Toronto. WESTOTL, T. S. I95x. The vertebrate-bearing strata of Scotland. Int. geol. Congr. x8 (2), 5-2x. P. F. Friend

This determination warrants further investigation, because if the structural relationships are as described and illustrated, it shows remarkably precise stratigraphical dating of a large intrusion and may throw some light on the rate of geological processes. W. B. Harland

(2) Chattanooga Shale U. Devonian]U. Devonian Young's Bend area, Tennessee, U.S.A. 269 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometric age ~38U-2°6Pb (no constants given) on uraniferous shale.

Depth Pb* Age (ft) U(ppm) Pb(ppm) 2°4Pb/2°~Pb ~°TPb/~°6Pb ~°sPb/~°6Pb (%) (m.y.) I75-12 1124-1 i924-6 u o.7684-o. I6 I'844-o'o4 13"2 45oa+7 o I76.95 9o.64-o.9 47.4+x-o o.o39o-t-o.ooo 5 o.6224-o.oo5 1.514-o-o2 28- 7 35oa+15 I8O'OO 68"34-o- 7 31.84-o.5 o'o375-t-o'ooo5 o'6o74-o'oo6 1"464-O'Ol 3 I"4 35°a4- I2 Age: 35oa4- Iom.y. (Cobb & Kulp I96o ). Stratigraphical age. The samples came from core Yn-9 from the upper black unit of the Gassaway member of the Chattanooga shale. Because the core was taken from only a few feet below the Devonian-Mississippian boundary, Cobb & Kulp (196o) assume that the adopted figure provides a firm minimum age for the Devonian-Mississippian boundary. Clark (I96 t) has challenged this conclusion, and by comparing the conodont content of the black shale unit with that of the standard conodont zonation of Europe, he suggests that the age of the unit ranges from upper- lower Upper Devonian to lower-middle Upper Devonian. The biostratigraphic age could be more precisely defined if the stratigraphical position of the core within the black shale unit were more accurately known.

References BATES, T. F. & Sa'~HL, E. O. 1957. Mineralogy, petrography and radioactivity of representative samples of Chattanooga shale. Bull. geol. Soc. Amer. 68, i3o5-14. CHOW, T. J. & McKINNEY, C. R. 1958. Mass spectrometric determination of lead in manganese nodules. Analyt. Chem. 3 o, 1499-5o 3. Ct~RK, D. L. 196I. U-Pb age determinations and Upper Devonian stratigraphy. Bull. geol. Soc. Amer. 72, 163-6.

-- & BEcmm, J. H. 196o. Upper Devonian correlations in western Utah and eastern Nevada. Bull. geol. Soc. Amer. 7 x, I67I-4 . COBB, J. C. & KULP, J. L. 196o. U-Pb age of the Chattanooga shale. Bull. geol. Soc. Amer. 7 x, 223-4. H.~ss, W. H. 1956. Age and correlation of the Chattanooga shale and the Maury formation. Prof. Pap. U.S. geol. Surv. 2116. Kvr.P, J. L. I96 I. [A. G. Smith]

Radiometric comment. From a detailed mineralogical and petrographical study of the Chattanooga shale, Bates & Strahl (I 957) concluded that the uranium is authigenic and was precipitated from sea-water. According to Cobb & Kulp (196o) this effectively separates the uranium from any radiogenic lead previously associated with it. Any common lead could be detrital or precipitated. The greater part of any detrital lead would have been carried by feldspar. There is about 9% (Bates & Strahl 1957) in the shale, much of which is considered authigenic. Cobb & Kulp therefore conclude that most of the common lead was precipitated from sea-water, and they estimate its isotopic composition from that inferred for oceanic lead in late Devonian time: 2°ePb/~°4Pb = I8"3; ~°TPb/2°4Pb = I5"7; ~°sPb/2°4Pb = 38"6. This composition is obtained by extrapolating backwards in time the isotopic composition of modern oceanic lead (Chow & McKinney 1958), assuming that the average U/Pb ratio in crustal rocks has not changed significantly since the late Devonian. The large uncertainties inherent in this procedure effectively eliminate con- sideration of 2asU-2°TPb ages. The two most probable types of alteration in the black shale--bulk lead loss and/or preferential loss of 2°6Pb--are believed to be negligible, and the ~3sU-2°6Pb ages are considered reliable minimum ages of the analysed samples. [A. G. Smith] 270 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. Clark & Becker (x96o) interpret the conodont assemblage as indicating their Zone C, which is correlated with the Upper Cheiloceras or Lower Platydymenia Stufe of Europe. These are the lowest two of four Stufe comprising the Famennien. P. F. Friend

(3) Bentonltes ha Grnad Gr~ve Formation Devonian]Devonian Shiphead, Cape Gasp6, Quebec, Canada [480 46' N, 64 ° x4' W].

Radiometric age K-Ar (2p = 4"76 × Io-l°year-X; ire = o'589 × Io-l°year-1; *°K]K = o.oII8 at.%)

'°K (ppm) '°Ar*#°K Age (m.y.) Biotite AK-I I3 (+325 mesh) 4"oI o.o245 3764-~6 AK-I38 (--325 mesh) 3"9o o'o253 388+27 Sanidine AK-136 (--270 to +325 mesh) 6.98 o'o251 3844-19 AK-I37 (--325 mesh) 5"43 o'o253 3874- I9 AK-X20 (--I20 to +270 mesh) 9" I8 0"0258 3944-20 Mean age: 3854-x5 [4-3]m.y.

Stratigraphical age. The samples came from unmetamorphosed bentonites in the lowermost xoo ft of the Shiphead (total thickness 28oft), lowest member of the Grand Gr~ve Formation (9ooft thick). The last-named has been assigned to the Lower Coblenzian Substage of the Devonian System (=Oriskany Substage).

Rgferel~e$ CUMMXNO, L. M. I959. Silurian and Lower Devonian formations in the eastern part of Gasp6 Peninsula, Quebec. Mem. geol. Surv. Can. 3o4 . SMITH, D. W. G., B.~DSO~RO, H., FOLINSBE~, R. E. & LIVSON, J. i96I. K/Ar age of Lower Devonian bentonites of Gasp6, Quebec, Canada. Bull. geol. Soc. Amer. 72, I7I-4. [A. G. Smith]

Radiometric comment. Quartz-feldspar aggregates and mixed-layer clays were also dated, and gave 34---m.y. and 325 m.y. respectively. The authors have not included these in the mean age. A. G. Smith

(4) Hecla Hoek mlca-schlsts Devonian/Ordovician Raudfjorden, Spitsbergen [79 ° 47' N, I2 ° E].

Radiometric age (I) K-Ar (2p = 4.72 × IO-l°year-1; ;te = 0-584 × Io-10year -1)

K20 (%) 4°At (mm3/g) atm. 4°At (?) 4°Ar*/4°K Age (m.y.) Biotite n-829 6.07 o. 0899 3" 6 [o. 0252] 389± I4 ~--275 5 "65 o "0935 I4"8 [0"0249] 3844 - I3 ~-686 9"42 o. I576 5"6 [o'o278] 4254- 22

Mean age: 399 [+ 13] m.y. 271 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(2) Rb-Sr (2 = x.47 × IO-11Year-x) Age (m.y.) Rb (ppm) Sr (ppm) STSr*(ppm) 8~Sr*/S~Rb 2 = z "39 2 = z "47 Biotite H-828 515 25" 8 o. 82 [o" oo562] [404] 382 4- 8 E-276B 54 x 7" z 0"86 [0"00561] [403] 379-4-6 ~-276B 542 7" 3 o" 86 [o" oo56o ] [4o2] 38o 4- 6 E-276B 54 x 8"8 O'85 [O'OO555] [398] 3754-6

Mean age: [4o2+x]m.y. (2 = x-39); [379 4- x]m.y. (2 = z'47 ). Adopted age using both methods: 383 4- xo m.y. (Hamilton, Harland & Miller I962).

Stratigraphical age. The samples analysed came from schists correlated with the lower Hecla Hock rocks, unconformably overlain by unmetamorphosed Red Bay Conglomerates; 3oom above the unconformity there is a fish fauna. Friend (I 96z) showed that the lowest faunal horizons of the Red Bay Series can be confidently correlated with the uppermost Downtonian of the Anglo- Welsh area, which is itself thought to be upper Lower Gedirmian. Upper Hecla Hock rocks in another locality contain Canadian (Ordovician) fossils.

Rgfergrlges FRmND, P. F. I96I. The Devonian stratigraphy of north and central Vestspitsbergen. Proc. Forks. geol. Soc. :$3, 77 -1 I8. HAMILa'Or;, E., H.~mt.AND, W. B. & MILLER, J. A. z96~. Isotopic ages from some Spitsbergen rocks. Nature, Lond. x95 , x x9z-2. [A. G. Smith]

Radiometric comment. See Item 7o. A. G. Smith

(5) C~!_~t_s granite U. Devonian/L. Devonian Calais, Maine, U.S.A. [45 ° I I' N, 67 ° z6' w].

Radiometric age K-Ar (decay constants not given; 4°K/K = z.22 × xo-4g/gK)

K (%) '°Ar* (ppm) '°Ar*#°Ar '°Ar*#°K Age (m.y.) Biotite Red Beach 4.83 o. z58 o-88 [o.o268] "] [41 x] Red Beach 4.83 o. x56 o'5x [o'o265] [~ [4o7] Red Beach 4.83 o. I53 o'89 [o.o26o][ 4o3 [4oo] Red Beach 4" 83 o. 153 o. 79 [o. o26o] .J [4oo] Keene Lake 5"66 o. x83 o'76 [o'o265] 4o7 Charlotte 5" 79 o- x87 o- 89 [o- o265] 4o6 Meddybemps 5" 2o o. 167 o. 92 [o. o263] 4o4

Mean age: 4044-8 [4-2]m.y.

Stratigraphical age. Fossiliferous slates of Middle Ludlow to Lower Gedinnian age are intruded and metamorphosed. A neighbouring granite is unconformably overlain by sandstone of Late Devonian age. The samples of granite come from four different localities. The granite overlain by Late 272 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Devonian sediments is slightly different petrographically from that analysed, and contacts between them are not exposed. However, they are probably similar in age.

References FAUL, H. I96o. KULP, J. L. 1961. [P. F. Friend & A. G. Smith]

(6) Slmp granite (adamelUte) Carboniferous/U. Silurian Shap, Westmorland, England [54 ° 32' N, 2 ° 4 I' w].

Radiometric age (1) K-At (2#----4"72 × IO-x°year-t; he = 0"584 × lo-l°year -x)

K (%) 4°At* (ppm) *°Ar*#°Ar 4°Ar*/4°K Age (m.y.) Shap adamellite: Biotite 7680 (I-B) 6" 36 O" 198 O" 91 [O" 0255] 393 ~ 12 Biotite 768o (I-B) 6"36 O. I96 O'97 [O'O253] 3914-20

Shap granite: Biotite 2o4o5 (2-B) 5"89 O" I85 O'9 ° [O'O257] 3974- I2 Biotite 2o4o 5 (2-B) 5 "89 o. I78 o.85 [o-o248] 3834- I2

Weighted average and mean age: 39x 4- 7 m.y.

(2) Rb-Sr (t i = 4"7 × Ioa°Year)

Kulp et al. (x96o) reported ages ranging from 364 to 385m.y., but Lambert & Mills (I96I) consider that these need correction and they are not quoted below.

Age (m.y.) Rb (ppm) Sr (ppm) S~Sr* (ppm) sTSr*/S~Rb 2=1.39 2=1.47 Shap adamellite: Biotite 7680 843 1 I. 5 I. 38 [o. 00578] [415] 391 4-15 845 X3"9 X"42 [0"00593] [425] 4 oI 4- I5

Shap granite: Biotite 20405 794 IO'O I "34 [o'0o596] [428] 4o34- x5 802 I I "4 I "32 [o "00580] [416] 394-4- I5

Mean age: [42I + 3]m.y. (~ = I'39); 397 -4- II [.4_ 3]m.y. (it = 1.47 ). Age: 395 + 5m.y. (Kulp I96I ) by both methods. Lambert & Mills (i96I) adopted 395m.y. as a mean age for all the Caledonian intrusions, including Shap.

Stratigraphical age. The metamorphic aureole affects Upper Silurian (Ludlovlan) strata; the basal Carboniferous (Lower Dinantian) near by contains pebbles of the rock. The age is thus post- Ludlovian and pre-Dinantian.

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References HOLMES, A. I959. KULP, J. L. 196I. LONG, L. E., GRIFFIN, C. E., MILLS, A. A., LAMBERT, R. ST J., GILETTI, B. J. & WEBSTER, R. K. I96o. Potassium-argon and rubidium-strontium ages of some granites from Britain and Eire..Nature, Lond. x85, 495-7. LAMBERT, R. ST J. • MILLS, A. A. 196 i. Some critical points for the Paleozolc time scale from the British Isles. Ann. N.Y. Acad. Sci. 9 x, 378--88. MAYNE, K. I., LAMBERT, R. ST J. • YORK, D. I959. The geological time-scale. Nature, Lond. 1183 ' ,-21 ~2. [P. F. Friend and A. G. Smith]

Radiometric comment. Using ~ld = 4.76 × Io-l°year-1, and R = )~e/2B = o" I23, Mayne, Lambert & York (i959) reported 475-5Iom.y. for the Shap adamellite. This was discarded by the same workers in Kulp et al. (196o). Holmes (I959) quoted the age from Kulp as 400 4- I5m.y. Dodson, Miller & York (I96I) report confirmation of Kulp et al. (I96o). These results are also reported in Lambert & Mills (196 I).

Stratigraphical comment. The Shap 'granite' is similar to the Creetown 'granite' of southern Scotland and the Leinster granite of Eire, all of which belong to the post-orogenic calc-alkaline suite of the Caledonides and form a well-marked petrographic province (Nockolds & Mitchell i948 ). According to Lambert & Mills (1961 ), this suite has volcanic members of proved Lower Devonian age which are believed to be contemporaneous with associated intrusive rocks. Rb-Sr and K-AT age-determinations on all three granites agree within the limits of experimental error, implying a Lower Devonian age. Further indirect evidence is provided by the Mell Fell conglomerate, a coarse, 'post-orogenic conglomerate' believed to have formed as a result of the earth-movements associated with the folding of the Silurian and subsequent intrusion of the Shap adamellite (Lambert & Mills 196 i), and to be of Lower Devonian age (Capewell I955). As mentioned above, pebbles of the adamellite occur in Lower Carboniferous strata, but the latter are underlain by conformable Upper Devonian rocks that cover the folded lower Palaeozoic strata.

References CAPEW~LL, J. G. i955. The post-Silurian pre-marine Carboniferous sedimentary rocks of the eastern side of the English Lake District. Quart. J. geol. Soc. Lond. xxx, 23-44. DODSON, M. H., MILLER, J. A. & YORK, D. I96I. Potassium-argon ages of the Dartmoor and Shap granites using the total volume and isotopic dilution techniques of argon measurement. Nature, Lond. xgo, 800-2. NOCKOLDS, S. R. & MITCHELL, L. R. x948. The geochemistry of some Caledonian plutonic rocks. Trans. roy. Soc. Edinb. 6x, 533. P. F. Friend & A. G. Smith

(7) Jackman monzonites and contact-metamorphosed rocks /L. Devonian

Jackman, north-west Maine, U.S.A. [45 ° 37' N, 7 °o I6' W].

Radiometric age (1) K-Ar (2p = 4.715 × io-X°year-1; 2e = 0"585 × IO-l°year-1; 4°K/K = 1.22 × Io-4g/gK)

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K(%) Air corrn (%) 4°Ar*#°K Age (m.y.) Biotite s-36o 9 (from quartz-monzonite) 5"49 I6-o 0-0231 3604-17 5"59 5"5 0"0239 3704-17 5 "56 O'O 0'0233 3694-15 Me- 1o (from quartz-monzonite) 7"°1 4"3 0-0226 3534-1o Me-9 (from porphyritic quartz-monzonite) 4"47 17 o-o236 3664- Io 4-Ol 32 o-o236 3664- xo B-3593 (chloritized biotite) 3" 74 3-2 o'o229 3564-15 Whole-rock: R-3447 (slate) 2- 61 l 3"0 0"0244 3774-18 2"71J R-3883 (cordierite-hornfels) 2 "84"~ O'O 0"0243 3654- IO ~, .86./ R-3444 (slate) 3.29 "~ I'8 0"0238 3684-15 3-26j R-3448 (slate) 2 "57 12 0-0224 3504-15 2 "57J Mean age: [364 4- 3] m.y.

(2) Rb-Sr (~ = 1 "39 × xo-nY ear-l) Age (m.y.) Rb (ppm) Sr (ppm) S'Sr* (ppm) sTSr*/S~Rb ;t=i "39 ~=1 "47 Biotite B-3609A 472 46. I O" 720 O" 00538 360 [386] 4- 28 [365]

Age: 36o m.y. (Hurley et al. 1959). Kulp (i 96 I) used 36o 4- 5 m.y.

Stratigraphical age. The monzonite intruded and metamorphosed the Seboomook slate, confidently placed in the Lower Devonian (Oriskany), on brachiopod evidence. [This is generally regarded as Upper Siegenian.] The samples come from two localities in the monzonite and four localities in the contact-metamorphic rocks.

References Ho~ms, A. I959. HURLEY, P. M., BOUCOT, A. J., ALBEE, A. L., FAUL, H., PINSON, W. H. & FAIRBAIRN, H. W. 1959. Minimum age of the Lower Devonian Slate near Jackman, Maine. Bull. geol. Soc. Amer. 7o, 947-9. KOLP, J. L. 196I. [P. F. Friend and A. G. Smith]

(8) Darttiioor granite Permian/Carboniferous South Devon, England [5°0 36' N, 3° 42' W].

Radiometric age Biotite

(I) Rb-Sr (~ = 1.47 X Io-nyear -1) Average of three figures on Hay Tor sample (separated biotite) 2o5o3:275 a 4- 6m.y. 275 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(2) K-Ar (;tp ----- 4" 72 × IO-l°year-1; ~ = 0"584 × IO-l°year -1) Average of six determinations on Hay Tor sample (biotite) 2o5o 3 using isotopic dilution method: 27 oa -4- 5m.y. One determination on Merrivale quarry sample (biotite) 2o59o: 262 a -4- 8m.y.

Stratigraphical age. The Dartmoor granite intrudes intensely folded Carboniferous sediments, of which the youngest exposed in the neighbourhood of the granite are Lower Westphalian. Sixty miles to the north-east are overfolded Lower Stephanian sediments in the Somerset coalfield, and since the granite is clearly post-orogenic, these relationships might establish a post-Lower Stephanian age for it. An upper limit to its stratigraphical position is harder to define. The near-by Permo-Trias, which presumably post-dates the intrusion of the granite, is largely unfossiliferous, and the Permian age of the oldest of these rocks can be supported only by indirect evidence. This intrusion seems to be of value only for a first approximation to the Permian-Carboniferous boundary.

References DODSON, M. H. I963. Isotopic ages from south-west England. D.Phil. thesis, Oxford. LAMBERT, R. ST J. & MILLS, A. A. 1961 (see Item 6). [M. H. Dodson]

Radiometric comment. The Rb-Sr age on separated biotite might be reduced slightly if data obtained on the whole rock can establish an age independently of the initial composition of common strontium. The Rb-Sr ages in Lambert & Mills (1961) were 2% too high, owing to an error in calibration. Certain published ages have been omitted from the K-Ar average: see Dodson (i963) for details. M. H. Dodson

The Dartmoor granite complex consists of at least four distinct magmatic units (Brammall & Harwood 1932), and it has undergone several subsequent phases of minor intrusive, deuteric, and mineralizing activity (Hosking 1962 ) . Ages generally quoted for the granite thus range from 3o6 to 25om.y. (see Miller & Mohr 1964 for summary). It is almost certain that the main intrusive phase must pre-date the extrusion of the Exeter Volcanic Series, dated at 28o 4- Iom.y. (Item 193), and it must certainly pre-date the earliest post-granitic episode of primary Variscan mineralization, given by Pockley (I963) and others as 29 ° -¢- 8m.y. With these facts in mind, we regard the contact metamorphism of two basic dykes at Meldon in Devon by Dartmoor granite 295 -4- 5 m.y. ago as the true initial age of intrusion (see Miller & Mohr 1964 and Fitch & Miller 1964). We therefore suggest that the intrusion of the Dartmoor granite took place 295 4- 5m.y. ago, probably early in the Stephanian.

References BRAMMALL, A. & HARWOOD, H. F. I932. The Dartmoor granites: their genetic relationships. Quart. 07. geol. Soc. Lond. 88, 171-234. FrrcH, F. J. & MILLER, J. A. i96 4. The age of the paroxysmal Variscan orogeny in England. Quart. 07. geol. Soc. Lond. 12o s, 159-73. HosKmo, K. F. G. i962. The relationship between the primary mineralization and the structure of south-west England. In Some aspects of the Variscan fold belt. (ed. Coe, K.) Manchester (Manchester University Press), pp. 135-54. MILLER, J. A. & MOHR, P. A. x964. Potassium-argon measurements on the granites and some associated rocks from south-west England. Lpool Manchr geol. 07. 4, IO5-26. POCKLEY, R. P. C. Four new uranium-lead ages from Cornwall. AIiner. Mag. [in the press].

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(9) Palisade sill ]Triassic Fort Lee, New Jersey, U.S.A. [4 °0 51' N, 73 ° 58' w].

Radiometric age K-Ar (~B = 4"72 × IO-x°year-X; ~e = o'584 × to-'°year-x)

K (%) 4°Ar*/total Ar 4°At* (ppm) 4°Ar*/'°K Age (m.y.) o259a Biotite from diabase 6-41 0.7: 0.0929 O"Oll 9 I944- 5 G259b Biotite from diabase 6"4: o'69 o'o891 o'otI 4 :864-5 Average for biotite x9o±5 0558 Very fine diabase at 0"52 0"27 0'0079 ° o'oi2 4 202 chilled contact 0358 Fine diabase o.6I o'67 o'oo924 O.O124 202 0658 Medium diabase o.73 o.68 o'oo896 O'OIOO9 I66 0858 Medium diabase o'55 o'84 o'oo574 0"00858 :42 0758 Coarse diabase 0"89 0"65 o'oio7 0.00988 162 0458 Hornfels, at lower :.8o o.66 o'o245 O.OII8 :93 contact (Erickson & Kulp 1961A) Age: :93 4- 3m.y. (Kulp 1961, p. i ii3).

Stratigraphical age. The Palisade sill intrudes the Stockton Formation of the Newark Group. The sill is believed to be related to basalt extrusions (Watchung flow, Hampden lava, etc.) that occur in stratigraphically higher parts of the Newark Group. The fauna of the Newark Group includes fish, reptiles, and many footprints, dated as Upper Triassic (Colbert and Gregory, in Reeside et al. 1957, pp. I456--62 ) . Fossils have been obtained below the Palisade sill, in New Jersey, and in the Portland Arkose, which in Connecticut and southern Massachusetts overlies the Hampden lava. It appears well established that the igneous rocks in the Newark Group are of about the same age as the adjacent sedimentary formations.

References EmcacsoN, G. P. & KULP, J. L. 1961A. Potassium-argon measurements on the Palisades sill, New Jersey. Bull. geol. Soc. Amer. 72, 649-52. ~ & ~ 196IB. Potassium-argon dates on basaltic rocks. Ann..N'.T. Acad. Sci. 9 x, 32I-3. KULP, J. L. I961. R~mlD~, J. B., Jr, et al. 1957. Correlation of the Triassic formations of North America, exclusive of Canada. Bull. geol. Soc. Amer. 68, 145 :-5 x4. [E. T. Tozer & J. Hacker]

(to) Gulchon Creek ImthoHth Triassic/Jurassic Ashcroft and Nicola areas, British Columbia, Canada. (1) [5 °0 45' N, 12I ° 15' W]; (2) (a) 5 °0 3 o' 03" N, 120 ° 56' 25" W; (b) 5 °0 29' 25" N, I20 ° 55t O5" W; (C) 5 °0 29' oo" N, I20 ° 55' OO" W; (d) and (e) 5 °0 28' 55" N, I2O° 55' 4 °" w; (f) 5 °0 29' IO" N, x2I ° 03' 3 °'' W; (g) 5 °o 29' tO" N, 121 ° O3' 20" W.

Radiometric age (I) K-At (~fl = 4"76 × xo-l°year-:; Jle = 0"589 × xo-l°year-1; 4°K/K = o-o118 at.%)

AK 44 biotite from quartz-granite: K = 3.31%, 4°Ar*/4°K = o.oi I5, age: 186m.y. Age: :85m.y. (Folinsbee, Baadsgaard & Lipson 196o, p. : 1).

(2) K-At (~B = 4"72 × lO-x°year-X; he = o'585 × xo-l°year-1) 277 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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K (%) 'OAr* (%) '°Ar*#°K Age (m.y.) Biotite: (a) Gsc 62-58 (from quartz-diorite) 4.25 zoo o.o153 245 (b) osc 62-59 (from quartz-diorite) 5"33 zoo o'ox4z 227 (c) GSe 62-60 (from quartz-diorite) 4" z5 zoo o.oz48 237 (d) csc 62-6z (from quartz-diorite) 6"47 zoo o'oz48 237 (e) osc 62-6i (from quartz-diorite) 6"47 xoo o.oz43 23o (f) GSC 62-62 (from granodiorite) 7" 4 ° I OO O" O151 242 (g) GSC 62-63 (from granodiorite) 7" z8 zoo o.oz39 224 (Leech et al. z963, pp. 39-42) Mean age: [235 d- 3] m.y.

Stratigraphical age. The Guichon Creek batholith intrudes the Nicola Group (Triassic) and is overlain by Middle Jurassic rocks. Tropitid ammonites of Karnlan, probably Upper Karniaal, age occur in the Nicola Group near Ashcroft, and Norian fossils obtained from a neighbouring area may also be derived from the Nicola Group. According to Crickmay, the oldest Jurassic rocks in the sequence resting on the intrusion are of Bajocian age. R. B. Campbell (in Leech et al. 1963, pp. 4z-2) states that the Guichon Creek batholith 'seems certainly to intrude Upper Triassic rocks of the Nicola Group though evidence for this is not completely conclusive ... No interpretation is offered to explain that the K-Ar ages of the biotite are about Middle Permian whereas the rocks of which the biotite is a constituent are part of a batholith that apparently intrudes Upper Triassic rocks'.

References BAADSGAARD, H., FOLINSBEE, R. E. & LIPSON, J. i96i. Potassium-argon dates of biotite from Cordilleran granites. Bull. geol. Soc. Amer. 72, 689-7o2. CmCKMAY, C. H. 193o. The Jurassic rocks of Ashcroft, British Columbia. Bull. Dep. Geol. Univ. Calif. I9, 23-74. I93I. Jurassic history of North America, its bearing on the development of continental structure. Proc. Amer. phil. Soc. 7 o, 5-Io2. DUFFEL, S. & MCTAGGART, K. C. z952. Ashcroft map-area, British Columbia. Mem. geol. Surv. Can. 262. FO~.ZNSB~, R. E., BAADSGAARD, H. & LIPSON, J. 196o. Potassium-argon time scale. Int. geol. Congr. 21 (3), 7-17 • FREBOLD, H. I953. Correlation of the Jurassic formations of Canada. Bull. geol. Soc. Amer. 64, 1229-446. LEECH, G. B., LOWDON, J. A., STOCKWELL, C. H. & WANL~SS, R. K. 1963. Age determinations and geological studies (including isotopic ages Report 4). Pap. geol. Surv. Can. 63-x 7. MCLEARN, F. H. I953. Correlation of the Triassic formations of Canada. Bull. geol. Soc. Amer. 64, x2o5-28. [E. T. Tozer & J. Hacker]

(I l) Topley intrusions Triassic and (?) Jurassic/U. Trias Central British Columbia, Canada. (a) 54 ° 5' N, X25 ° 2 t W; (b) 54 ° 2' N, I25 ° 2' W; (c) 54 ° 3 I' N, z24 ° 54' w.

Radiometric age K-Ar (2# = 4"72 X Io-l°year-1; 2e = 0"585 X IO-a°year-x) 278 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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K (%) 'OAr* (%) '°Ar*#°K Age (m.y.) Biotite (a) Gsc 61-35 (from diorite) 7"75 Ioo 0.01094 I78 (b) csc 61-36 (from granite) 6-80 9 x 0-00835 I38 (c) csc 61-37 (from granite) 5" 19 xoo o.oo94o x54 (Lowden et al. I963, pp. 22, I34 ) Age: 178m.y. (see stratigraphical comment). Note. A fourth sample, from an outcrop mapped as Topley quartz-diorite, gave an age of 63 m.y. On the basis of this age-determination, this outcrop is now regarded as a younger intrusion.

Stratigraphical age. The Topley intrusions of central British Columbia, comprising granite, granodiorite, etc., intrude the Takla Group. Rocks assigned to the Takla Group have yielded Upper Triassic Halobia (Karnian or Norian) and Monotis subcircularis (Norian). Poorly preserved 'Arnio- ceras' (Sinemurian) and 'Harpoceras' (Toarcian) have also been recorded from the Takla, but not from areas immediately adjacent to the Topley intrusions. The I-Iazelton Group, which has provided ammonites of Middle Bajocian age, rests unconformably upon the Takla Group and contains detritus evidently derived from the Topley intrusions. These intrusions appear to have been emplaced between the Norian and the Middle Bajocian, possibly around the time of the Toarcian-Bajocian boundary (Tipper x963).

References ARMSTRONG, J. E. 1949. Fort St. James map-area, Cassiar and Coast districts, British Columbia. Mere. geol. Surv. Can. 252. FVa~BOLD, H. x953 (see Item IO). LOWDEN, J. A., STOCKWELL, C. H., TIVVER, H. W. & WANLESS, R. K. I963. Age determinations and geological studies (including isotopic ages--Report 3). Pap. geol. Surv. Can. 62-x 7. TXVPFR, H. W. 1963 . Nechako River map-area, British Columbia. Mem. geol. Surv. Can. 324. [E. T. Tozer]

Stratigraphical comment. The ages obtained from the Topley intrusion were strongly weighted by Armstrong (i949) as follows: the intrusion consists of granitic, dioritic and syenitic phases. Only the granitic phase intrudes the Upper Triassic Takla Group, and it also occurs as boulders in Middle Jurassic conglomerates. The granitic phase is, therefore, of Lower Jurassic age, perhaps as young as the Toarcian-Bajocian boundary. The date of 178m.y. obtained from the dioritic phase (to which the stratigraphical evidence of time of emplacement does not apply) was also considered to be the age of the granites. Three absolute ages have now been obtained from the Topley granites: i38m.y, and I54m.y., quoted above, and I63m.y. (Baadsgaard, Folinsbee & Lipson I96x , p. 696; data: Fort Fraser granite [54 ° o 4' N, 124 ° 4I' w], K = 3.6o%, 4°Ar*/40K ~ O.OLOO; age: I63m.y. calculated on ;tp = 4" 76 × IO-l°year-a; he = o.589 × xo-l°year-1). Tipper (in Lowden et al. I963, pp. i35-6) does not consider any of these three ages accurate because there are many dykes, numerous shear-zones, chloritized biotites, and perhaps younger intrusions in the granites. Any or all of these factors may have caused loss of argon and therefore low biotite ages. None of these criticisms applies to the diorite, which was unaltered and gave the date of 178 m.y.--the only reliable date for the intrusion.

Refsre~e$ BAADSO~O.RD, H., FOLINSa~, R. E. & LIPSON,J. i96i (see Item io). LOWDEN, J. A. et al. x963 (see above). M. K. Howarth 279 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(12) Marshalltown Formation U. Cretaceous/U. Cretaceous Outcrop 2 "5 miles south of Moorestown, Burlington County, New Jersey, U.S.A. [39 ° 56' N, 74 ° 56' w].

Radiometric age K-Ar (various constants used) Glauconite: K = 4" 4o%, 4°Ar*#°K = o. oo409. (obsolete values of constants used) age: 92"6m.y. (Wasserburg, Hayden & Jensen 1956 , p. 162; Wasserburg & Hayden 1956 , pp. 131 , 134); 78m.y. (Kazakov & Polevaya 1958, p. 384). age: 72 "5m.y. (Herzog, Pinson & Cormier 1958, p. 729; see also Lipson 1956, p. 149, fig. I ; Lipson 1958, p. 146, fig. 7); 93 m.y. (Davidson i96o , p. 335, no. 35).

(2/~ ----- 4.72 × IO-l°year-X; ~ = o'584 X xo-l°year-X) age: 69 4-4m.y. (Kulp I959, pp. 691, 694).

(;tp = 4"72 X Io-l°year-1; ~ -- 0.585 X IO-l°year-a) age: 68m.y. (Hurley 1961, p. 295). Age: [69] m.y.

Stratigraphical age. Upper Cretaceous (Wasserburg, Hayden & Jensen 1956). References DAVIDSON, C. F. I96o. HERzoc, L. F., PmsoN, W. H. & Colu~ms, R. F. 1958. Sediment age determination by Rb/Sr analysis of glauconite. Bull. Amer. Ass. Petrol. Geol. 4~, 7 I7-33. HURLEY, P. M. x961. Glauconite as a possible means of measuring the age of sediments. Ann. N.Y. Acad. Sci. 9z, 294-6. KAZAKOV, G. A. & POLEVAYA, N. I. 1958. [Some preliminary data on elaboration of the post-Precambrian scale of absolute geochronology according to glauconites.] Gheokhimiya, x958 (4), 296-3o6. [In Russian. English translation in Geochemistry, 1958 (4), 374-87 .] Kin.p, J. L. 1959. Absolute age determination of sedimentary rocks. World Petrol. Congr. 5 (1), pap. 37, 689-7o4. LIPSON, J. 1956. K-A dating of sediments. Geochim. et cosmoch. Acta, xo, 149-5 I. 1958. Potassium-argon dating of sedimentary rocks. Bull. geol. Soc. Amer. 69, 137-5o. WASSERBURO, G.J. & HAYDEN, R.J. i956. A40-K 4° dating..National Academy of Sciences-.National Research Council Publication 40o, 13 I-4. , HAYDEN, R. J. & JENSEN, K. J. 1956. A4°-K 4° dating of igneous rocks and sediments. Geochim. et cosmoch. Acta, xo, 153-65. [B. M. Funnell]

Stratigraphical comment. Recent opinion places the Marshalltown Formation near the top of the Tayloran, which is equated with the Campanian of the European succession (Dorf & Fox 1957, fig. I, pp. 6-7; Murray 196i , p. 357).

References DOR~, E. & Fox, S. K. 1957. Cretaceous and Cenozoic of the New Jersey coastal plain. Guidebook for Field Trips, Atlantic City Meeting 1957. Geological Society of America, pp. 1-25. MURRAY, G. E. 1961. Geology of the Atlantic and Gulf Coastal Province of'North America. New York (Harper). B. M. Fun_nell

(13) Navesi~k Formation U. Cretaceous/U. Cretaceous Clayton, New Jersey, U.S.A. [39 ° 39' N, 75 ° O5' W]. 280 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometric age Rb-Sr (it = x "47 x Io-nyear -1) Glauconite 0-322o: Rb ----- 221 ppm, Sr = 16 "9 ppm, SvSr* ---- o. o6 ppm, [s'Sr*/S 7Rb = o" ooo96], age: 67 4- I, m.y. (Hurley et al. I96O, p. ,8o7). (it= "39 × 'o-l'year-1) : Rb----- 22oppm, Sr= ,7ppm, sTSr* =o.o6,ppm, age: 7om.y. (Cormier et al. I956, p. ,682); 7' 4- ,xm.y. (Comfier i956; Comfier et al. '957); 62-7om.y. (Kazakov & Polevaya ,958, p. 384); 7' -b IIm.y. (Kulp '959, P. 694); 7' 4- xxm.y. (Holmes x96o, p. 2o,); 62, 7om.y. (Davidson ,96o, p. 335, no. 34); 67m.y. (Cahen ,96o, p. 424); 67m.y. (Hurley x96,, p. 295). Age: [69]m.y. (it -~ 1.39); [65.5]m.y. (it = 1.47 ).

Stratigraphical age. Upper Cretaceous.

References CA}raN, L. ,960. CORMmR, R. F. I956. Rubidium-strontium ages of glauconite and their application to the construction of a post-Precambrian time scale. Ph.D. Thesis, Massachusetts Institute of Tech- nology, Cambridge, Mass. , HERZOG, L. F., PXNSON,W. H. Jr. & HURLEY, P. M. I956. Rubidium-strontium age determinations on the mineral glauconite. [Abstract.] Bull. geol. Soc. Amer. 67, I68I-2. et al. x957. Variations in isotopic abundances of strontium, calcium, and argon, and related topics: Rubidium-strontium ages of the mineral glauconite and their application to the coi:struction of a post-Precambrian time-scale. Massachusetts Institute of Technology Department of Geology and Geophysics Fourth Annual Progress Report (for 1956-7), p. 2. DAVIDSON, C. F. I96o. HOLMES, A. x959. HURLEY, P. M. I96I (see Item I2). , CORMmR, R. F., HOWER, J., FAmBAmN, H. W. & PINSON, W. H. Jr. x96o. Reliability of glauconite for age measurement by K-Ar and Rb-Sr methods Bull. Amer. Ass. Petrol. Geol. 44, I793 --8o8. KAZAKOV, G. A. & POL~VAYA, N. I. I958 (see Item x2). KuLP, J. L. x959 (see Item 12). [B. M. Funnell]

Stratigraphical comment. Only the Bridgeton Formation (Quaternary) and the Cohansey Sand (Upper Tertiary) crop out iv, the vicinity of Clayton, which is approximately I o miles down-dip from outcropping Navesink Formation. The sample is therefore probably from a borehole, and the basis for referring it to the Navesink Formation is not known. The Navesink Formation is correlated by planktonic Foraminifera with the middle part of the Navarro, and the early to mid- Maestrichtian of the European succession; it is referable to the upper part of the Globotruncana rornicata--G, tricarinata Assemblage Zone (Olsson I963, p. 649 ).

Ref 6'f~llc e$ Or SSON, R. K. I963. Latest Cretaceous and earliest Tertiary stratigraphy of New Jersey coastal plain. Bull. Amer. Ass. Petrol. Geol. 47, 643-65 • B. M. Funnell

(x4) Hornerstown Formation Palaeocene-L. Eocene/Palaeocene-L. Eocene Clayton, New Jersey, U.S.A. [39 ° 39'N, 75 ° O5'W]. 28I Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometric age Rb-Sr (itB = I "47 × Io-nY ear-l) Glauconite G-322I: Rb = 24o ppm; Sr = xo. 3 ppm; sTSr*----o.o6 ppm [s~Sr*/87Rb = o.ooo88], age: 56 4- 6m.y. (Hurley et al. I96O, p. I8o7). (~ = I "39 × lO-lXyear-X). Rb = 238 ppm, age: 6om.y. (Cormier et al. 1956, p. I68I); 59 4- 6m.y. (Cormier 1956; Cormier et al. 1957) ; 6om.y. (Kazakov & Polevaya 1958, p. 384); 59 4- 6m.y. (Kulp 1959, p. 694); 59 4- 6m.y. (Holmes 1959, P. 2o2); 6om.y. (Davidson i96 % p. 334, no. 2o); 56 4- 6m.y. (Cahen 196o, p. 424); 56m.y. (Hurley 1961 , p. 295); Age: [63"5]m.y. (it = 1"39); [6o.o]m.y. (it ---- 1.47 ). K-Ar (itB = 4"72 × IO-l°year-1; 2e----o'585 × Io-l°year -x) K-----6.2I%, air corm = 32%, 4°Ar*]4°K=o.oo346, age: 58m.y. (Hurleyetal. 196o, p. 18o7) ; 58m.y. (Hurley 196I,p. 295). Age: [58-5] m.y. Stratigraphical age. Lower Eocene, Hornerstown Formation. References CAHEN, L. 196o. CORMIER, R. F. 1956 (see Item 13). et al. 1956 (see Item 13). et al. 1957 (see Item 13). DAVIDSON, C. F. 196o. HOLMES, A. x959. HURLEY, P. M. 1961 (see Item 12). et al. 196o (see Item 13). KAZAKOV, G. A. & POLEVAYA, N. I. 1958 (see Item 12). KULP, J. L. I959 (see Item 12). [B. M. Funnell]

Stratigraphlcal comment. Only the Bridgeton Formation (Quaternary) and the Cohansey Sand (Upper Tertiary) crop out in the immediate vicinity of Clayton, which is 7 miles down-dip from outcropping Hornerstown Formation. The sample is therefore probably from a borehole. The basis for referring it to the Hornerstown Formation, and in particular to a Lower Eocene portion to that formation, is not known. The lower part of the Hornerstown Formation is referable to the Globorotalia compressa- Globigerinoides daubjergensis Assemblage Zone, and is correlated by planktonic Foraminifera with the lower Midway Group of the Gulf Coast and the Danian of the European succession. The middle part is referable to the Globorotalia pseudobulloides Subzone of the Globorotalia angulata Assemblage Zone, and is correlated by planktonic Foraminifera with the upper Midway Group of the Gulf Coast, which is considered to be equivalent to the Thanetian of the European succession. The upper part of the Hornerstown Formation is referable to the earliest part of the Globoro- talia acuta--Globigerina spiralis Subzone, of the Globorotalia angulata Assemblage Zone, and is considered to be equivalent to part of the Sparnacian of the European succession (Olsson 1963, p. 655). The lower and middle parts of the Hornerstown Formation are therefore Palaeocene, and the upper part either Upper Palaeocene or Lower Eocene (the choice depending both on its presumed equivalence with the Sparnacian and the placing of that stage in either the Palaeocene or Eocene).

Reference OLSSON, R. K. 1963 (see Item x3). B. M. Funnell

(15) Hornerstown Formation Palaeocene-L. Eocene/Palaeocene-L. Eocene Birmingham, Burlington County, New Jersey, U.S.A. [39 ° 59' N, 74 ° 43'W]. 282 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometric age K-Ar (various constants used) Glauconite: K = 6.oo%, 4°Ar*]4°K = o.oo296 (Obsolete values of constants used) age: 67" 6 m.y. (Wasserburg, Hayden & Jensen x956, p. x62; Wasserburg & Hayden I956 , pp. 131 , 134); 68m.y. (Kazakov & Polevaya 1958, p. 384; see also Lipson I956 , p. 149, figs. 1, 2; Lipson 1958 , p. 146, figs. 6, 7) ; 68m.y. (Davidson 196o, p. 335, no. 25); age: 52"8m.y. (Herzog, Pinson & Cormier I958, p. 729) (hp -----4"72 X lO-l°year -1) 3, ----- 0.584 × io-:°year -x) age: 51 2r- 3m.y. (Kulp 1959, pp. 69I , 694); 51 + 3m.y. (Cahen 196 % p. 424). (hB = 4"72 × Io-X°year-:; ~ = o'585 × to-l°year -1) age: 5om.y. (Hurley 196I, p. 295). Age: [5o] m.y.

Stratigraphical age. Basal Tertiary (Wasserburg, Hayden & Jensen x956).

References CAHEN, L. I96O. DAVIDSON, C. F. I96O. HERZOO, L. F., PINSON, W. H. & CORMIER,R. F. 1958 (see Item I2). HURLEY, P. M. 1961 (see Item 12). KAZAKOV,G. A. & POLEVAYA,N. I. 1958 (See Item I2). KULP, J. L. 1959 (see Item I2). LIPsON, J. 1956 (see Item i2). 1958 (see Item 12). WASSERBURG,G. J. & HAY"DEN,R.J. 1956 (see Item I2). HAYDEN, R.J. & JENSEN, K.J. 1956 (see Item 12). [B. M. Funnell]

Stratigraphical comment. For comments on the age of the Hornerstown Formation see Item 14.

Refe?g//ce OmsoN, R. K. I963 (see Item I3). B. M. Furmell

(t6) Veraya Tier sediments M. Carboniferous/M. Carboniferous Kuibyshev area, U.S.S.R. At 840.9 to 847.9m depth in Varvarovskaya Plot borehole.

Radiometric age K-At (1, ~.p =4"9 × IO-t°year-1; he =0"602 × Io-l°year-1; 2, hp =4"9 × lO-l°year-t; i~e-----0"555 × Io-l°year-X; 3, ~-p = 4"72 × Io-l°year-X; he = o'584 × I°-l°year-:; 4°K/K = 1"22 × lO -~ g/gK) Glauconite: K = 5"24%; atm. 4°Ar ---- I2%, 4°Ar* = o-955 × Io-Tg/g, 4°Ar*#°K = o'o15. Age: (x) 23om.y.; (2) 255m.y.; (3) 237m-y • (Kulp I96O ). Age : [241]m.y.

Stratigraphical age. The Veraya Tier is the lowest unit of the Moskovian Stage (C~mx), of the Russian Middle Carboniferous and is approximately equivalent to Westphalian C of the Upper Carboniferous in western Europe. Note: Item 64 is also from the Veraya Tier, but from a different borehole. 283 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

References DAVXDSON, C. F. x96o. KnZAKOV, G. A. & POLEVAYA, N. I. I958 (see Item x2). KULP, J. L. I96o. [E.H. Francis]

(x7) W~l~W~m sediments Palaeocene-L. Eocene/Palaeocene-L. Eocene South Island, New Zealand [c. 45 ° xS'S, 17O° 40'E].

Radiometri¢ age K-Ar (various constants used) Glauconite no. 5t : K ---- 5"82%, *°Ar*/~°K ----- o'oo276 (Obsolete values of constants used) age: 49"2 4- 3"om.y. (Lipson I956 , pp. x49-5o); (Lipson I958, PP- I44, I46); 44m.y. (Kazakov & Polevaya I958, p. 384); 49m.y. (Davidson I96O, P. 334, no. I9). (2# = 4"72 × xo-X°year-a; Xe = o'584 × IO-x°year-1) 46 ± 3m.y. (Kulp 1959, pp. 69 x, 694). (2# ----- 4"72 x Io-a°year-a; ~ = o.585 x xo-a°year-~) 46m.y. (Hurley x96I , p. 295, table I); (55m.y. given for Palaeocene of New Zealand in abstract [Lipson I958, p. x37; Davidson x96o, P. 334, no. 21]) Age: [46. 6] m.y.

Stratigraphical age. Waipawan (Palaeocene) (Lipson x956, I958).

Rgfo'~e$ DAWDSON, C. F. I96O. HURLEY, P. M. I961 (see Item 12). KAZAKOV, G. A. & POIAEVAYA,N. I. I958 (see Item I2). KULP, J. L. x959 (see Item I2). LtesoN, J. x956 (see Item i2). ~. x958 (see Item x2). [B. M. Funnel1]

Stratigraphical comment. The type-locality of the Waipawan Stage is in North Island (Hornibrook, in Fleming x959, p. 444). It is regarded by Hornibrook (ibid, p. 445) as Palaeocene [Upper Palaeocene] although two forms on which he relies for this correlation, Discoaster multiradiatus and Globorotalia aft. crassata atqua, both [assuming that G. aft. crassata aequa ----- G. aequa] range up into the Lower Eocene (Bramlette & Sullivan i96x, p. x6x ; Bolli x957, p. 63) and the latter, which occurs only in the top two zones of the Palaeocene, is already present in the Tappanina glaessneri mudstone bed at the base of the Waipawan (Hornibrook, ibid, p. 114)- However, Bramlette & Sullivan (t96i , p. i37 ) also refer the Waipawan to the Upper Palaeocene. It is difficult to determine the precise correlatives of the type Waipawan in the North Otago district of South Island, from which Lipson's sample appears to have come (Hornibrook & Harring- ton I957, p. 66o). Hornibrook (in Fleming 1959, P- 445) has, however, suggested that the Moeraki Beds may be partly Waipawan, the other part being Teurian [Lower Palaeocene] (ibid, p. 398). The age of the sample probably falls in the range Palaeocene--Lower Eocene; but greater precision is not possible without more exact details of its location and horizon. ReJ~gre~¢.$ BOLLX, IL M. I957. The Genera Globlgerina and Globorotalia in the Palaeocene-Lower Eocene Lizard Springs Formadon of Trinidad, B.W.I. Bull. U.& nat. M~. 2x5, 6I--8I. Bm~ML~rrE, M. N. & SULLIVAN, F. R. I96I. Coccolithophorids and related Nannoplankton of the early Tertiary in California. Micropaleontology, 7, 129-88. 284 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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FLEMING, C. A. I959. New Zealand. Lexique Stratigraphique International, 6, Oceanic (4), x-527. HORNmROOK, N. D~. B. & IL~INOTON, H.J. x957. The status of the Wangaloan Stage. aV.Z. 07. Sci. Tech. (s) $8, 655-7o. B. M. Funnell

(x8) Lower Tertiary sediments (just below Walpawan Stage) middle Palaeocene-L. Eocene/middle Palaeocene-L. Eocene North Island, New Zealand [c. 39 ° 35's, I76° X5'E].

Radiometric age K-At (R = o. 1 Io, 2 = 5"58 X xo-l°year -x) Glaueonite no. 38: K = 6.82%, 4°Ar*]4°K = o-oo258, age: 46.x-t-2.8m.y. (Lipson I956, pp. I49-5o; Lipson z958 , pp. r44, I46) : (55m.y. given for Palaeocene of New Zealand in abstract [Lipson i958 , p. x37]. ) Age: [43" 6] m.y.

Stratigraphical age. Cretaceous-Palaeocene boundary (Lipson x958 , p. x46 ).

References HURLEY, P. M. I96I (see Item I2). LIPSON, J. I956 (see Item i2). -- I958 (see Item x2). lB. M. Funnell]

Stratigraphical comment. The location indicated by Lipson (x958 , p. I45 , fig. 5) for this sample is near the crest of the Ruahine Range in a Jurassic greywacke group, approximately 25 miles north-west of the nearest outcrop of the Teurian Stage of the Dannevirke Series, and about 28 miles north-west of the nearest outcrop of the Walpawan Stage of the Dannevirke Series (Kingma I962). According to Hornibrook (I96I) and Kingma (I962) the complete Dannevirke Series comprises the following stages: Teurian, Waipawan, Mangaorapan, Heretaungan, and Porangan, ranging from Palaeocene to mid-Middle Eocene. If Lipson's sample came from the Dannevirke Series of the Hawke's Bay district its designation as 'just below Walpawan' would imply that it came either from the Teurian glauconitic sandstones, or from the Tappanina glaessncri mudstone bed, which was later referred to the Waipawan by Hornibrook & Harrington (1957, p. 666). The Teurian is regarded by Hornibrook (in Fleming x959, p. 399) as equivalent to the Danian [Lower Palaeocene]. For a full discussion of the Waipawan, see stratigraphical comment, Item t 7. The age of the sample probably falls in the range middle Palaeocene--Lower Eocene; but greater precision is not possible without more exact details of its location and horizon.

References BOLU, H. M. x957 (see Item I7). BRAMLETTE, M. N. & SULLXVm'q, F. R. I96I (see Item x7). FLEMING, C. A. x959 (see Item x7). t-IO~BROOK, N. DE B. r 96 I. Tertiary Foraminifera from Oamaru district (N.Z.), Part I N Systema- tics and distribution. Paleont. Bull. JV.z. 34, x-x92. & HARRINGTON,H.J. i957 (see Item 17). KaNOMA, J. T. I962. Sheet 11 Dannevirke. Geological map of New Zealand (I : 25o,ooo ). LIPSON, J. 1958 (see Item x2). B. M. Funnell 285 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(19) Upper Permian organic limestone U. Permian]U. Permian Sokolki [Sokolka] Village, mouth of Vyatka River, U.S.S.R. [53 ° 38'N, 51° 28'E].

Radiometric age K-Ar (2B = 4"9 × IO-:°year-X; 2e = o'602 × lO-:°year-x) Glauconite: K = 5"68%, atm. 4°Ar = I5% , 4°Ar*/4°K = o.oIoI, age: i6om.y. (R = o. i17; )le = 0.555 × xo-X°year-1) age: 175 m.y. Age: [i 65]m.y.

Stratigraphical age. Kazanian (Upper Permian). Name of formation not quoted.

Reference KAZAKOV, G. A. & POImVAYA, N. I. 1958 (see Item I2). [D. B. Smith]

Stratigraphical comment. The sample was collected from an outcrop in Sokolki Village, and is stated by the authors to have reliable biostratigraphic dating. Sokolki lies on beds of Kazanian age. The calculated age, using two different constants, appears to be much too low and probably indicates loss of argon. D. B. Smith

(20) Upper Palaeoeene sediments, Kodor River U. Palaeoeene/U. Palaeocene Abkhaziya, Georgia, U.S.S.R.

Radiometric age K-Ar (2# = 4"9 × lO-x°year-X; 2e = 0-602 × Io-X°year-1) Glauconite: K = 6.99%, 4°Ar*#°K = 0-0035 , age: 56my. (R = o.117; 2e = 0"555 × IO-x°year-X), age: 62m.y. (Kazakov & Polevaya 1958 , pp. 379, 381,384); 62m.y. (see also Davidson 196o , p. 334, no. 22). ()Ia = 4"72 X IO-:°year -x )le ----- 0-584 X Io-X°year-:) age: 58 4- 6m.y. (Kulp 1959, pp. 69I , 694 ) (a) = 4"72 × IO-xOyear-~; 2e ----- o'585 × Io-:°year-x) age: 56my. (Hurley 1961, p. 295). Age: [59] m.y.

(2• = 4"72 × lO-x°year-:; 2e-----0"557 × IO-l°year-X) Glauconite: K = 6"99%, 4°Ar*/i°K = 0"0030, age: 53m.y. (Polevaya, Murina & Kazakov 196I, p. 3o4); 58 + 6m.y. (Kulp I961 , p. 1113, sample 28). Age: [5 °. 5] m.y.

Stratigraphical age. Pgl 2, top of Lower Palaeogene (Kazakov & Polevaya 1958, PP. 379, 382, sample 2); Upper Palaeoeene (Polevaya, Murina & Kazakov I961, p. 3o4). Lower-Middle Eocene (Kulp 1959, p. 694).

]{efere?zces DAVIDSON, C. F. 196o. HURLEY, P. M. I96I (see Item 12). K.AZAKOV, G. A. & POLEVAYA, N. I. 1958 (see Item 12). KULP, J. L. 1959 (see Item 12). 1961. POLEVAYA, N. I., MUmNA, G. A. & KAZAKOV, G. A. 1961. Utilization of glauconite in absolute dating. Ann. N.Y. Acad. Sci. 9 x, 298-3IO. [B. M. Furmell] 286 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(21) Eocene sediments, Turgay M. Eocene/M. Eocene North of the ArM Sea, U.S.S.R.

Radiometric age K-Ar (ha = 4"72 × IO-l°year-a; he = o'557 × lO-l°Ye ar-1) Glauconite: K = 4"99%, 4°Ar*# °K = o-oo29 Age: 51 [49"o]m.y. (Polevaya, Murina & Kazakov i96I , p. 3o4).

Stratigraphical age. Tassaranskaya suite [Tas-Aran Series] of Middle Eocene (Polevaya, Murina & Kazakov I96x , p. 3o4).

Reference POLEVAYA, N. I., MURINA, G. A. & KAZAKOV, G. A. I96I (see Item 20). [B. M. Funnell]

(2a) Upper Eocene sediments, River Volga U. Eocene/U. Eocene Stalingrad hole 4077, depth i I9m , Volga River area, U.S.S.R.

Radiometric age K-Ar (hp = 4"72 × IO-x°year-X; '~e = 0"557 × Io-a°Year-l) Glauconite: K = 5"48%, 4°Ar*#°K ---- o.oo26. Age: 46 [44-o]m.y. (Polevaya, Murina & Kazakov x96I, p. 3o4).

Stratigraphical age. Kiev Stage.

Referevlce POLEVAYA, N. I., MURINA, G. A. & KAZAKOV, G. A. I96I (see Item 20). [B. M. Funnell]

Stratigraphical comment. The Kiev Stage is presumed to be Upper Eocene (see Item 23), but no supporting data are available. B. M. Funnell

(23) Upper Eocene sediments, Ciscaucasia U. Eocene/U. Eocene Umantsevo hole No. 54 [59] ~, depth 3 xom [3 xo-27 m] ~ Predkavkaz'e (Ciscaucasia), U.S.S.R.

Radiometric age K-Ar (2B = 4"9 × IO-a°year-1; he = o.6o2 × Io-X°year -1) Glauconite: K = 5-3i%, 4°Ar*#°K = o.oo2I, age: 35m.y. (R--o.xi7; 2e =o'555 × IO-l°year-1) age: 38m.y. (Kazakov & Polevaya I958, pp. 379, 38I, 384; see also Davidson i96o, p. 334, no. I3). I~ = 4"72 × ,o-a°year-l~ = o'584 × xo-X°year-1)age: 36 + 4m.y. (Kulp x959, PP. 691,694). = 4"72 x IO-x°year-X; ~ = o-585 × ×o-×°year -x) age: 35m.y. (Hurley I961, p. 295). (hp=4"72 × IO-a°year-1; 2e =o'557 × IO-x°year-a) age: 37m.y. (Polevaya, Murina & Kazakov 196x , p. 3o4). Age: [35" 6] m.y.

Stratigraphical age. Pga Kiv Kiev Tier (Upper Eocene) Upper Palaeogene (Kazakov & Polevaya I958, PP. 374, 379, 382, sample i). :~ Thus in Kazakov & Polevaya 1958, P. 384. 287 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

References DAVlDSON, C. F. 196o. HURLEY, P. M. 196I (see Item I2). KAZAKOV, G. A. & POLEVAYA, No I. I958 (see Item I2). KULP, J. L. 1959 (see Item 12). POLFVAYA, N. I., MURmA, G. A. & KAZAKOV, G. A. 196I (see Item 20). lB. M. Funnell]

Stratigraphical comment. The Kiev Stage falls between the Buchak Stage (Middle Eocene) and the Kharkov Stage (Lower Oligocene) (Larkin /n Likharev 1958, pp. 7io-11; Tchikhatchev in Likharev et al. 1958, pp. 246, 683). This is consistent with the Upper Eocene age indicated by Kazakov & Polevaya (I958, p. 374) in their abstract, but no supporting data are available.

References LIKHAREV, B. K. et al. I958. Lexique 8tratigraphique International, a, U.S.S.R. (I, 2), 1-564, 565-I212. KAZAKOV, G. A. & POLEVAYA, N. 1. I958 (see Item 12). B. M. Funnell

(24) Pitchblende deposits Eocene/Palaeocene Front Range, Colorado, U.S.A.

Radiometric age s35U-~°'Pb: (it= [9"72 -4- o.2x] × Io-lOyear-t converted from t½) 2ssu/~35U = ' 37" 7 4- o'5 285U_*o~pb Age of pitchblende Location Sample (m.y.) Source Wood Mine, Gilpin Co. K--7 t 42 ~ 4- 2 (Eckelmann & Kulp 1957) Wood Mine, Gilpin Co. 56a -4- 2 (Nier, Thompson & Murphey I941) Wood Mine, Gilpin Co. 64a 4- 2 (Stieff, Stern & Milkey 1953) Iron Mine, Gilpin Co. 7oa 4- 3 (Stieff, Stern & Milkey 1953) Richards Mine, Gilpin Co. X--6 62 a 4- 6 (Eckelmann & Kulp 1957) German Mine, Gilpin Co. x-8 5C+ 2 (Eckelmann & Kulp i957) Gilpin Co. 6I a -4- 2 (Nier, Thompson & Murphey I94I) Copper King Mine (,), Larrimer -- 56a 4. 2 (Phair & Levine 1952) County Copper King Mine (2), Larrimer -- 75 a-4- 5 (Phair & Levine I952 ) County

Adopted age: 59 a 4- 5m.y. (Quoted byHolmes [1959] as 59 -4- 5m.y.; by Cahen [I96o ] as 6o + 5m.y.; Kulp [I959, 196o] as 6I 4- 5m.y.; Kulp [1961] as 59 4- 2m.y.; Faul [1954, I96O] quotes original uncorrected values.) [A. G. Smith]

Radiometric comment Abstract from Eckelmann & Kulp. Because the thorium concentration was low in all cases, the common lead correction was obtained from the 2°sPb content. The isotopic composition of the common lead was derived from a galena at Idaho Springs, Colorado. This correction is not con- 288 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns sidered an important source of uncertainty because none of the common lead in the Front Range shows evidence of radiogenic contamination, and any other normal common lead would have given similar results. The absence of apparent surface weathering and the existence of radiogenic equilibrium were established for at least two samples (K-6 and K-8). Of the three methods that could in this case be used for age-determinations (235U/2°Tpb; 233U/z°ePb; 2°TPb]2°sPb), only the first was accepted as reliable. The 238U/~°aPb method was not used because of possible radon leakage (in all cases the age given by this method is slightly lower than the corresponding 235U/~°Tpb age) and 2°Tpb]2°6Pb in the o-5oom.y, age range is very sensitive to any error in the lead isotope ratio. The adopted age was found by taking the mean of ~35U/9°~Pb ages, weighting ages inversely as the square root of the error for each value.The adopted error is the standard deviation of the mean. Previously determined ages have been recalculated using the constants given above and probable errors have been estimated. The paper reviews all previous work. It is assumed that all the pitch- blendes represent an essentially instaneous mineralization, and were not deposited over a period of several million years. Further comment. It is not certain whether the assumption of geologically instantaneous and simultaneous deposition of separate pitchblende deposits is valid. The reason for adopting different ages and errors is not clear (Kulp i96o , i96t).

References CAIm~, L. 196o. ECKELMANN, W. R. 8c KULP, J. L. 1956. Uranium-lead method of age determination. Part I, Lake Athabasca problem. Bull. geol. Soc. Amer. 67, 35-54. & 1957- Uranium-lead method of age determination. Part I I, North American localities. Bull. geol. Soc. Amer. 68, i I 17--4 o. FAUL, H. (ed.) 1954. Wuclear geology. New York (Wiley). I96o. HOLMES, A. I959. KULP, J. L. 196o. --. i96i. NmR, A. O., THOMPSON, R. W. & 1V[URPHEY, B. F. 194i. The isotope constitution of lead and the measurement of geological time. III. Phys Rev. 60, 112-16. PHAm, G. & ImvLnE, H. I952. Notes on the differential leaching of uranium, radium and lead from pitchblende in H~SO4 solutions. Econ. Geol. 48, 358-9 . STmFF, L. R., STERN, T. W. & MILm~Y, R. G. 1953. A preliminary determination of the age of some uranium ores of the Colorado plateau by the lead-uranium method. Circ. U.S. geol. Surv. 27 x, i-19. [A. G. Smith]

Stratigraphical comment. Holmes (1947, p. 14o ) stated: ' ... there is some doubt as to the exact geological age of the ore-deposits associated with the close of the Laramide orogeny. The general view is to assign them to the end of the Cretaceous, but some geologists consider that they may not all be of the same age and that some may be as late as the close of the Palaeocene'. Knopf (x957) later showed that the veins were younger than the Palaeocene Fort Union Series, and regarded them as having been formed at or near the end of the Palaeocene. Faul (I96o, pp. 638-9) continued to regard the occurrences simply as post-late Cretaceous, but Holmes (1959, p. 2o2), Cahen (I96O , p. 424), and Kulp (x96o, p. 2o; 1961 , pp. 1 lO7-12 ) adopted a late Palaeo- cene or Palaeocene-Eocene age for them. Kulp (in discussion of Curtis, Savage & Evernden x96 t, P. 346) stated that T. S. Lovering had reviewed the geological setting and concluded that a position near the Palaeoeene-Eocene boundary was most likely. 289 L Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Refgrg//ce$ CAHEN, L. I96o. CtmTLS, G. H., SAVAOE, D. E. & EWRNDEN, J. F. 1961. Critical points in the Cenozoic. Ann..N.Y. Acad. Sci. 9 x, 342-6. FAVL. H. I96o. HOLmeS, A. I947. I959. KNOPF, 1957. Measuring geologic time. Sd. Mon., .N.Y'. 85, 225-36. KULP, J. L. 196o.

-- 196i. B. M. Funnell

(25) Upper PHoeene glauconltlc sandstone U. Pliocene/U. Pliocene Mendocino County, California, U.S.A.

Radiometric age K-At (2# = 4"72 × xo-l°year-X; 2e = 0"584 × lO-a°year-1) Glauconite gA I92: K = 5%, attn. 4°At = 93%, *OAr*/4°K ---- o'ooo3o44, age: 5"2 m.y. (Evernden etal. 196i , pp. 81, 9I); 3"5 4- o.5m.y. (Kulp 1961, pp. IIO 7, Ii12) Age: [5" 2o] m.y.

Stratigraphical age. Upper Pliocene (Evernden et al. 196 I, pp. 8 I, 91 )

References EVm~NDEN, J. F. et al. I96I. KULP, J. L. 1961 [B. M. Funnell]

(26) Lower Pliocene biotite-latite welded tuff U. Miocene-L. Pliocene/U. Miocene--L. Pliocene West Walker River Canyon, California, U.S.A. (9"7 miles north of Fales Hot Springs, Highway 395, o11 east side of river).

Radiometric age K-Ar (2# -- 4"72 × lO-l°year-a; ;re = 0'584 × xo-l°year-1) Biotite KA I32: K = 6" I2%, atm. 4°Ar = 66%, 4°Ar*#°K = 0"000624, age: Io'7m.y. (Evern- den et al. I96I , pp. 81, 86) (2# = 4" 72 × xo -×°year -1; 2e = o. 585 × I o-l°year -t) age: I o. 6 m.y. (Curtis, Savage & Evernden 1961, P- 345); xo.6 4- o'5m.y. (Kulp 196i , pp. XLO7, 1Ii2) Age: [ i o. 7] m.y.

Stratigraphical age. Lower Pliocene based on flora (Evernden et al. 1961, p. 86), probably very near the top of the Clarendonian (Curtis, Savage & Evernden 196i , p. 345)-

References CURTIS, G. H., SAVAGE,D. E. & EVERNDEN,J. F. I96I (see Item 24). EVERNDEN, J. F. et al. 1961. KULP, J. L. 196 I. []3. M. Funnell] 29 ° Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. Although this sample was attributed to the Lower Pliocene on the basis of the flora (Evernden et al. I96I), and stated to be probably very near the top of the Clarendonian (Curtis, Savage & Evernden 1961), no supporting data were given. On the basis of mammalian faunas the Clarendonian has been correlated with the Pontian of the European succession (Wood I941, pl. I; Axelrod 1956 , table I), but Stirton (1951, p. 77) has subsequently suggested that it may correlate with the Sarmatian (see also Kleinpell 1938 , pp. 173-4, fig. I4). Durham, Jahns & Savage (1954, fig. 2) indicate that the Clarendonian is co-extensive with the Sarmatian. In Europe the Pontian is regarded as either Lower Pliocene or Mio-Pliocene, and the Sarmafian as Upper Miocene. Kleinpell (i 938, P. 174, fig. 14) implies that the Clarendonian is co-extensive with the Delmon- tian of California, whereas Axelrod (1956 , table I) shows it overlapping with the Californian Molmian below and the Repettian above. The Delmontian has been regarded both as Upper Miocene and as Lower Pliocene the Repettian as Lower Pliocene. The sample therefore appears to be either Upper Miocene or Lower Pliocene.

References AXELROD, D. I. 1956. Mio-Pliocene floras from west-central Nevada. Bull. Dep. Geol. Univ. Calif. 33, 1-322. CURTIS, G. H., SAVAGE, D. E. & EVErmD~N, J. F. 1961 (see above). DURHAM, J. W., JAHNS, R. H. & SAVAGE, D. E. 1954. Marine-nonmarine relationships in the Cenozoic section of California. Bull. Calif. Div. Mines, 17o, ch. 3, 59-7I. EVERND~I% J. F. et al. 196i. KLEINPELL, R. M. 1938. Miocene stratigraphy of California. Tulsa (American Association of Petroleum Geologists). STIRTON, R. A. 195 I. Principles in correlation and their application to later Cenozoic holarctic continental mammalian faunas. Int. geoL Congr. 18 (2), 74-84. WOOD, H. E. (Chairman) 1941. Nomenclature and correlation of the North American continental Tertiary. Bull. geol. Soc. Amer. 52, 1-48. B. M. FunneU

U. Miocene-L. Pliocene] (27) Coal Valley Formation, basal biotite rhyolite tuff U. Miocene-L. Pliocene 'Near top of unit A6 of Aldrich Station Formation' (Evernden et al. 1964, p. I76 ). Coal Valley, Nevada, U.S.A.

Radiometric age K-Ar ('~B = 4"72 × IO-l°year-1; 2e ----- 0"584 × lO-l°year-X) Biotite KA 414: K = 6"37%, atm. 4°Ar = 56%; 4°Ar*/4°K = o'ooo655"~, age: 12 .om.y. (Even- den et al. 1961, pp. 81, 88). (2p = 4"72 × to-l°year-a; 2e----o'585 × IO-l°year-x) age: x2.om.y. (Curtis, Savage & Evernden 1961, p. 385). These authors quote additional values of t I. ibm.y, and 11.2bin.y. for the Clarendonian of Nevada, but no details are given. KuIp (i961 , pp. t IO7, 1I 12) gives 12.o 4- o'5 m.y. and quotes additional values of t 1. t b 4- o. 5 and t t. 8 b 4- o- 5 m.y. for the Clarendonian of Nevada. Age: [t2]m.y. (K = 6-37%, arm. 4°Ar = 52%) age: 11.2bm.y. (Evernden et al. I964, p. 176 ).

Stratigraphical age. Lower Clarendonian (Lower Pliocene). Bottom of C1 Zone of Axelrod in the Coal Valley formation. Excellent vertebrate control, close to Upper Miocene-Lower Pliocenc t Personal communication, Evemden 1964. 291 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items boundary (Evernden et al. x96I, p. 88). At the very bottom of the Clarendonian, at the very base of the Pliocene at top of the Miocene, Barstovo-Clarendonian (Curtis, Savage & Evernden x96I, p. 385).

Refer~l, ce$ CURTIS, G. H., SAVAGe., D. E. & EVEm~DF.N,J. F. x96I (see Item 24). EVE~DPN, J. F. et al. 196 x. EVEm~DEN, J. F., SAVAO~, D. E., CURTIS, G. H. & JAM~S, G. T. I964. Potassium-argon dates and the Cenozoic mammalian chronology of North America. Amer. ft. Sci. 262, :45-98. KULP, J. L. I96I. [B. M. Funnell] Stratigraphical comment and references. As for Item 26, plus: STmTON, R. A. I939. The Nevada Miocene and Pliocene mammalian faunas as faunal units. Proceedings of the Sixth Pacific Science Congress, pp. 627-4 o. B. M. Funnell

{~11) Lower Hemphm~,- tuff U. Miocene/U. Miocene Crystal "citric biotite dacite tuff, Smith Valley 'beds', Morgan Ranch Formation, eastern edge of Smith Valley, Nevada, U.S.A. (Evernden et al. 1964, p. 178).

Radiometric age K-Ar (2/? = 4"72 × Io-l°year-:; 2e = 0"585 × Io-l°year -a Biotite: no further data given; age: 9-1bm.y. (Curtis, Savage & Evernden I96I, p. 345); 9-I b 4- o-5m.y. (Kulp i96I , pp. 11o7, III2) leA 485 : K = 4"47%, atm. 4°Ar = 64%, age 9-3 b m.y. (Evernden et aL I964, p. I78 )

Stratigraphical age. Lower Hemphillian, probably at the very bottom (Curtis, Savage & Evernden x96:, p. 345).

References AXELROD, D. I. I956 (see Item 26). CURTIS, G. H., SAVAGE, D. E. & EVERI~D~N,J. F. 196I (see Item 24). EVERNDEN, J. F. et al. I964 (see Item 27). KULP, J. L. :96x. WILSON, R. W. i936. A Pliocene rodent fauna from Smiths Valley, Nevada. Publ. Carneg. Instn, 473, 15-34. [B. M. Funnell]

Stratigraphical comment. The Hemphillian may be either Pontian or post-Pontian (Wood I94I, pl. x ; Stirton x95i , p. 77; Axelrod :956, p. I3). Durham, Jahns & Savage (i954, fig. 2) show the Iqemphillian as equivalent to the Pontian and all except the highest part of the Plaisancian. Kleinpell (I938 , p. I74, fig. I4) implies its correlation with his 'Lower Pliocene' [Repettian], and Axelrod (x 956, table I) indicates a correlation with the middle and upper Repettian and part of the overlying Venturian. If correlation of the Hemphillian with the Pontian is correct and the lower part of the Pontian is Upper Miocene, then a Lower Hemphillian occurrence might be Upper Miocene. Correlation of the Hemphillian with the Repettian of the Californian succession suggests, however, that it is unlikely to be pre-Pliocene. Indeed, if the Delmontian is included in the Pliocene, or if the Hemp- hillian is post-Pontian, a mid-Pliocene age might be suggested for the Iffemphillian. From these considerations it is concluded that a lower Hemphillian occurrence might be any- where between Upper Miocene and mid-Pliocene in age. 292 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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The assumption that the determination recorded by Evernden el al. (x 964) is the same as that referred to by Curtis, Savage & Evernden (I96I) and Kulp (I96I) is based on the similarities in the reported stratigraphical and radiometric ages and locations.

References. As for Item 26. B. M. Funnell

(29) Shale in Pennsylvanlan limestone Carboniferous/Carbonlferous Oklahoma, U.S.A. (no precise locality given).

Radlometric age K-At (~p = 4"72 × Io-a°year-1; 2e = o'584 × Io-l°year -1) 'Illite' from bulk sample of shale. K = 2.86%, atm. 4°At = 32%, 4°Ar*#°K = o.oi87. Age: 295m.y.

Stratigraphical age. Westphalian stage of Lower Pennsylvanian (Otterville Limestone).

Reference EWm~DEN, J. F. et al. 196 i. [E. H. Francis]

Stratigraphical comment. The Otterville Limestone lies near the top of the Morrow Series in south Oklahoma and is equivalent to a horizon in the lower part of the Westphalian (Moore et al. x 944, chart 6).

Reference MOORE, R. C. (Chairman) et al. x944. Correlation of Pennsylvanian formations of North America. Bull. geol. Soc. Amer. 55, 657-7o6- E. H. Francis

Radiometric comment. See Item 48. A. G. Smith

(3 o) Upper Kuttung Series (?Paterson toscanlte) U. Carboniferous/U. Carboniferous Lower Hunter Valley, New South Wales, Australia.

Radiometric age K-At (~p ----- 4" 72 X Io-l°year-1; he----o'584 X Io-a°year -1) Biotite from toscanite lava: K = 6.6o%, 4°Ar*/4°K----- o.ox75. Age: 278m.y. (Kulp [i96I ] used 287m.y. )

Stratigraphical age. The Upper Kuttung Series consists mainly of fresh-water conglomerates, tiUites, and extrusive volcanic rocks, and is regarded as approximately equivalent to Upper Carboniferous.

References Evs~M, J. F. et al. 196 I. KuLP, J. L. i96I. [E. H. Francis] 293 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Stratigraphical comment. Since this lava is stated to be Upper Kuttung and described by Kulp (I96I) as 'Uppermost Carboniferous', it is probably the Paterson toscanite, which is younger than the (?)Stephanian fauna obtained by Campbell (x96x) from the Isaacs Formation (see also Items 65, 66). Rgf6T6'?/,C¢ CAMPBELL, K. S. W. I96x. Carboniferous fossils from the Kuttung rocks of New South Wales. Palaeontology, Lond. 4, 428-74 • E. H. Francis

(3 x) Harzburger gabbro U. Carboniferous/L. Carboniferous Near Harzburg, Hartz, Germany.

Radiometric age K-At (2p ---- 4"72 × xo-t°year-a; ,~e ----- o'584 × xo-X°Year-l) Biotite separated from gabbro: K = 4"94%, atm. 4°Ar ---= 8%, ~°Ar*#°K = o'o2o 9. Age: 327 m.y.

Stratigraphical age. Post-Kulmgrauwacke (Vis6an), pre-Stephanian.

Referente EVERNDEN,J. F. et aL x 96 x. [E. H. Francis]

(32) Fithlan iillte Carboniferous/Carboniferous Fithian, Illinois, U.S.A.

Radiometric age K-At (;lp = 4"72 × IO-l°year-x; ~e ----- 0"584 × xo-t°year -a) Bulk sample ofFithian Illite (an underclay), from type-locality: K ----- 5 "o7%, arm. 4°At ---- 32%, ~OAr*#OK = o-oi53. Age: 246 m.y.

Stratigraphical age. This is the underclay of the Macoupin Cyclothem of the McLeansburg Group and is lower Upper Pennsylvanian (Lower Stephanian-Missouri Series). R~re//c¢ EVRRNDEN, J. F. et al. 196 i. [E. H. Francis]

Radiometric comment. According to Evernden et al. (I96I), this 'appears to be an excellent age determination. Possibly, the absence of pre-erosion argon is due to the fine-grained or authigenic nature of the Fithian illite'. See Item 48. E. H. Francis & A. G. Smith

(33) Granites and pegrnatlte U. Triassic/L. Carboniferous Middle Urals, U.S.S.R.

Radiometric age K-Ar (~tB ----4"72 × xo-X°year-1; ~-----0"557 × IO-x°year-X; 4°K/K ----x.22 × Io-4g/gK) 294 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(I) Kum~aksky granite-porphyry: 235 b [225] m.y. (2) Suundooksky granite: 235b[225] m.y. (3) Borsuksaisky syenite-pegmatite: 225 b [215] m.y. Minerals not specified, experimental data not given. Mean age: 232b[222]m.y.

Stratigraphical age. Given as late Carboniferous by Ovchinnikov & Harris (I96o , p. 43) without supporting stratigraphical data.

Rgd~ret/ce Ovem_mcmov, L. N. & HAmus, M. A. 196o. Absolute age of geological formations of the Urals and pre-Urals. Int. geol. Gongr. 2x (3), 33-45 [E. H. Francis]

Stratigraphical comment. According to Nalivkin (i 96o), the synorogenic intrusions of the Urals cut Lower Carboniferous and are covered by Upper Triassic rocks.

Rej~renee NALrV-raN, D. V. 196o. The geology of the U.S.S.R. A short outline. (Transl. Tomkeieff, S. I.) Oxford (Pergamon Press). E. H. Francis

(34) Swedish kolm U. Cambrian/U. Cambrian Bi Uingen region, southern Sweden [580 2o' N, X3 ° 30' E].

Radiometric age U-Pb (constants not given) Adopted minimum age: 5ooam.y.

Stratigraphical age. The stratigraphical age of the shales containing the kolm lenses is Upper Cambrian; this attribution is based on the presence of the trilobite Peltura scarabaeoides.

Reference COBB, J. C. & KULP,J. L. I96I. Isotopic geochemistry of uranium and lead in the Swedish kolm and its associated shale. Geochim. et cosmoch. Acta, 24, 226-49. [A. G. Smith]

Radiometric comment. The concentration and isotopic composition of uranium and lead in about 20 samples of kolm (small pods rich in organic material) and associated black shale have been determined. All samples show discordant U-Pb ages with a characteristic pattern: ~ssU-~°ePb< 235UJO7pb< 2°7pb-yO6pb. The discordance is attributed to at least two processes: (i) preferential removal of ~°ePb from the kolm and its deposition in the shale or removal from the area, owing to movement of an intermediate member of the 238U-2°ePb decay series (22nRa and/or 2~YRn) ; and (ii) removal of bulk radiogenic lead (Y°6Pb and 2°7pb). Thermal activity is ruled out as the cause, and the migration is attributed to ground-water leaching. It is not known whether this leaching is of recent origin or whether it has been continuously operative since deposition. Cobb & Kulp concluded that allowance for these processes indicates a minimum age of 5oom.y. and a true age probably near this figure, but they reject it as a calibration-point on the 'absolute' time-scale. [A. G. Smith]

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Stratigraphical comment. The Olenid Shale, in which the radioactive variety of coal known as kolm or kulm occurs at certain levels, has a fauna of trilobites and brachiopods. The sequence has been divided into faunal zones, which are thin and generally sharply limited; Westerg[trd (1947) put forward 6 zones and the equivalent of 24 subzones. The subzone of Peltura scarabaeoides is the eighteenth subzone from the base of the Upper Cambrian and is therefore not particularly close to the top: it may best be referred to as medial Upper Cambrian•

Reference WESTm~OARD, A. H. I947. Supplementary notes on the Upper Cambrian trilobites of Sweden. Sverig. geol. Unders. Ser. C, no. 489 . J. W. Cowie

(35) Hotailuh bathoHth Jurassic/Triassic Cassiar Mountains, British Columbia, Canada [580 08' 3 o'' N, x29 ° 52' oo"w].

Radiometric age K-Ar (2# = 5"3o × IO-x°year-t; ~ = o'585 × xo-X°year-1) ose 62-7I : K = 6"55%, 4°At* = too%, 4°Ar*/4°K = o-x19. Age: 193 m.y.

Stratigraphical age. The Hotailuh batholith is 'intrusive into volcanic rocks and minor sedimentary rocks which to the west in Dease Lake Map-area have yielded a Karnian (early Upper Triassic) fauna. In this region the Karnian rocks are commonly overlain conformably by Norian (mid Upper Triassic) limestone and it is assumed that the granitic rocks are younger than the Norian •.. Karnian rocks near the batholith are overlain unconformably by Lower Jurassic strata. On Mt Meehaus, south of the confluence of Tanzilla and Stikine Rivers, ... conglomerate in the Lower Jurassic sequence carries pebbles and cobbles of granitic rocks similar in lithology to those represented by [the dated specimen]' (H. Gabrielse, in Leech et al. t963, p. 46).

Reference LE~eu, G. B. et al. t 963 (see Item to). [E. T. Tozer & J. Hacker]

(36) Scaldisien sediments Pliocene/Pliocene Kruisscheus, Belgium.

Radiometri¢ age K-At (~#- 4"72 × IO-t°year-X; ~e----0"585 × IO-x°year-x) Glauconite o-3897: K ----- 4"99%, air corm ----- 62%, 4°Ar*/4°K = o'ooo47, age: 7 + tm.y. (Hurley et al. I96o , pp. x8oo, x8o7) ; 7m.y. (Hurley t96I , p. 295 ) ; 7 -4- x m.y. (Kulp I96I, pp. I IO7, I I I2). Age = [8" o5] m.y.

Stratigraphieal age. Scaldisien, Pliocene (Hurley et el. I96o, p. I8O7).

References I-ItmzEx,, P. M. r96I (see Item x2). et al. 1960 (see Item i3). KtrnV, J. L. I96I. lB. M. Funnell] 296 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Stratigraphical comment. The term Scaldisien is used in Belgium in two senses. Scaldisian sensu stricto includes only the KaUo Formation (zone of Weptuneacontraria), which is currently regarded as earliest Pleistocene; whereas Sealdisian sensu lato also includes the underlying Kattendyk and Luchtbal formations (zones of Isocardia cor and Pecten gerardi), which are regarded as Pliocene. The sense in which the term Scaldisian is being used is not stated. A guess may be hazarded that the radiometric determination was obtained from Kattendyk materials (zone of Isocardia cor), but this cannot be relied upon. Appropriate details of the provenance of the materials used would allow a much more satisfactory strafigraphical assignment to be made. B. M. Funnell

(37) Rocky Boy carbonatlte M. and U. Eocene] L. Eocene Western Hill County, Bearpaw Mountains, Montana, U.S.A.

Radiometric age K-Ar (constants not given) Age K(%) *°Ar(ppm) *°Ar*#OArt°t *"Ar*#°K (m.y.)

Biotite 7' 76 o.o292 o'57 [o.oo3o8]~ 524-2 o" 029 ° o" 35 [o" oo3o6]~

Age: 52 -4- 2m.y. (Faul x96o, pp. 638, 642; Kulp I96i , pp. I IO7, x i i2; Faul in Curtis, Savage & Evernden I96x, p. 349).

Stratigraphical age. Middle or late Eocene; the stock is correlated with intrusions that cut sediments of Wasatch (early Eocene) age. Associated volcanic rocks are interbedded with sedimentary layers bearing fossil plants of middle and late Eocene age (Faul 196o, p. 638 ). Post-early Eocene (Kulp I96x , p. x xo7). P~j~rer/ce$ FAUn, H. x96o. CURTIS, G. H. SAVAGe., D. E. & EV~RNDEN, J. F. x96x (see Item 24). Ku~', J. L. 196 I. lB. M. Funnell]

(38) Welded daclte tuff M. Miocene/M. Miocene Near middle of Barstow Formation (Evernden et al. x964, p. x76), Barstow syncline north of Barstow, California, U.S.A.

Radiometric age K-At (2p = 4"72 × xo-l°year-1; he = 0"584 × xo-X°year-1) Biotite m~ 449: K = 4"83%, arm. *OAr= 4o%, *°Ar*#°K = o'ooo89, age: x5"2m.y. (Evernden et al. I961, pp. 8I, 88); x5"2m.y. (Curtis, Savage & Evernden I96I, p. 345); x5"2 -4- o'5m.y. (Kulp I96I, pp. Iio7, Ixx2). (K -= 4"83%, arm. *OAr = 4i%) I5.1 m.y. (Evernden et al. I964, p. I76 ). Age: [I5.2]m.y.

Stratigraphical age. Barstovian (type-locality) (Evernden et al. x96 i, p. 88).

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Refirence$ CURTIS, G. H., SAVAGE,D. E. & EVERI~EN, J. F. x961 (see Item 24). EVERNDEN, J. F. et al. 196 I. et al. I964 (see Item 27). KULP, J. L. 196 i. [B. M. FunneU]

Stratigraphical comment. Inasmuch as the Clarendonian may be equivalent to either Pontian or Sarmatian (see Item 26), the Barstovian may be equivalent to either the Sarmatian (Upper Miocene) or Tortonian (Middle Miocene). Wood (194 i, pl. I) preferred the correlation with the Sarmatian. Durham, Jahns & Savage (i954, fig. 2) indicate that the Barstovlan is equivalent to the upper Helvetian and the Tortonian (Middle Miocene).

~e/~Te?/¢e$ DURHAM,J. W., JAHNS, R. H. & SAVAGE,O. E. x954 (see Item 26). WOOD, H. E. 194I (see Item 26).

B. M. Funnell

(39) Miocene vltrie tuff M. Miocene/M. Miocene Tuff 205 ft below top of Caliente Formation in Dry Canyon near the north-west comer of San Guillermo Q uad., Upper Cuyama Valley, Ventura County, California, U.S.A.

Radiometri¢ age K-Ar (~p ---- 4"72 × xo-t°year-1; ~ = 0"584 X IO-l°year-1) Biotite x~x I6I : K -- 4"2%, atm. 4°At = 9x%, 4°Ar*#°K = o'ooo894, age: I5.2m.y. (Evernden et al. 196 x, pp. 8 x, 86-7) ; x5" 2 m.y. (Curtis, Savage & Evemden x96 I, pp. 345--6) ; 15" 2 4- o. 5 m.y. (Kulp 196i , pp. Iio7, III2); I5.2m.y. (Everndenetal. I964, p. 175 ).

Stratigraphical age. Barstovian, based on excellent fauna (Evemden et al. I96I, p. 86).

Refirences. See Item 38. [B. M. Funnell]

Stratigraphical comment. See Item 38.

References JAMES, G. T. I963. The paleontology and nonmarine stratigraphy of the Cuyama Valley Bad- lands, California [Pt. I]. Bull. Dep. Geol. Univ. Calif. 45, I-I54- WOOD, H. E. I94I (see Item 26). B. M. Funnell

(4o) Snoqualmie granite batholith mid-Miocene/late Oligocene North Cascades, Washington, U.S.A.

Radiometrie age K-Ar (no constants or data given) Biotite: age: I6"3, I7"o, 17.7m.y., av. x7"obm.y. (Folinsbee, in Curtis, Savage & Evernden x96x, P. 347); I7 "°b -4- o" 5 m.y. (Kulp I96I , pp. xIo7, IxI2) 298 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical age. Intrudes late Oligocene (John Day vertebrate fauna) and is generally accepted as mid-Miocene (Kulp 196i , p. 1112).

Ref grence$ CI.rRTIS, G. H., SAVAGE, D. t~. ~1; t~VERNDIgN~J. F. I96I (see Item 24). KULP, J. L. x96 z. [B. M. Funnell]

Radiometric comment. Earlier age-determinations made on zircon and apatlte from this batholith gave spuriously high values of 63 m.y. and 7oom.y. respectively (Larsen, Keevil & Harrison 1952 , pp. lO5O-1).

Refere'ac8 LAmEN, E. S., KEPVlL, N. B. & HARRISON, H. C. 1952. Method for determining the age of igneous rocks using the accessory minerals. Bull. geol. Soc. Amer. 63, lO45-52. B. M. Fum~ell

(4 z) Athls granite middle L. Cambrian/late Pre-Cambrian Pont-Erambourg, Orne (Normandy), France [480 5 i'~1, o ° 3 x'w].

Radiometric age Biotite and muscovite (1) K-Ar (Ap = 4"72 X xo-a°year-a, ~e = 0"585 X IO-x°year-1, 4°K/K ----- O'OlI9 at. %)

K(%) 4°Ar(cm 8, stp) 4°Ar*/4°Art°t 4°Ar*/4°K Age (m.y.) Biotite 5"31 1.18 × Io -~ 0-95 [0"0326] 489-4- IO Muscovite 5"73 I'32 × 1o-4 o'95 [o'o338] 53I[5O5] + II

(2) Rb-Sr (A = 1 "39 × Io-Uyear-X; s~Sr/SSSr = 0"0843; 86Sr]SSSr = o"1194)

87Sr* × lO s Age (m.y.)

Rb(ppm) S~Rb(ppm) (mol/g) sTSr*/STSrt°t s~Sr*/S~Rb = i "39 ~[ ----" x "47 Biotite 395 I I I. 9 o" 982 o. 5 [o" 00763] 545 -4- 11 [517] Muscovite 16o 45" 3 o. 364 o. o8 [o. oo699] 503 + 6o [474]

Age: 54o [+ Io]m.y. (Graindor & Wasserburg 1962); mean of (I) and (2): [496 4- 9]m.y.

Stratigraphical age. This granite metamorphoses the rocks of the Upper Briov6rien and is unconformably overlain by the basal conglomerate of the Cambrian of Normandy. The conglomerate, containing rounded pebbles of metamorphic rocks in an arkosic matrix, is not metamorphic (Graindor 1953, i957). For the age of the Cambrian of Normandy, see Item 42.

References GRAINDOR, M. J. 1953. Sur l'~tge du granite d'Athis (Orne). C.R. Acad. Sci., Paris, 236, 504--6. 1957. Le Briov6rien dans le nord-est du MassifArmoricain. Mdm. Carte gdol. ddt. Fr. 1949-56. & WASSERBURG, G.J. 1962. D6terminations d'figes absolus dam le nord du Massif Armori- cain. C.R. Acad. Sci., Paris, 254, 3875-7 • [L. Cahen & F. Doff/

Stratigraphical comment. See Item 42. 299 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

(4[2) Vlre=Carolles granite middle L. Cambrlan/latc Pre-Cambrian (x) (a) Saint Michel dc Montjoic; (b) Saint Pois; (2) Coulouvray; (3) (a and b) Saint Michel des Loups; Manchc & Calvados (Normandy), France [480 46'N, x° 2'W to 480 46'N, ,o 32' W].

Radiometrie age (A) K-Ar (constants used by Starik [I96,]) Biotite *OAr* X Io -1~ *°Ar*#°K (using K(%) (molecules/g) 4°K/K = o.o, I9 at. %) Age (m.y.) (I) (a) 6.69 4- o.44 4" 73 4- o.4 ° [o.o385] "~ f[565] (b) 6.38 4- o. 38 4"28 4- 1.37 [o-o365] j 586 4- 22 ~[542] (2) 6.56 4- o.o, 4"52 4- o'o3 [o'o375] 582 4- i [552] (3) (a) 4"88 4- o.22 3" 12 4- o.32 [o'o348 ]'] F [518] (b) 5.46 4- o. I8 4"23 4- o'38 [o'o422] ~- 582 4- x4 .{ [612] (c) 5"o6 4- o.29 3"27 4- 0.28 [o-o352]] L [523] Age: 583 [552] 4- 9m.y. (Kaplan & Leutwein 1963) (~p = 4"72 × Io-l°year-x; ~ = 0"585 X IO-x°year-X; *°K/K = o'otI 9 at. %) Age: 553 4- xom.y. (Cahen & Dord) (B) Rb-Sr (~ = t "39 X xo-nyear -x)

S'Sr* × lO s Age (m.y.) Rb (ppm) (mol/g) 87Sr*/STSr sTSr*/STRb 2 = "39 2 = 1"47 Whole rock 312 o'718 o" 5 [o'oo7o7] 5o8 4- ,o [479]

Pegmatite from Vire-Carolles granite, from near Sarfilly (Graindor & Wasserburg I962 )

Stratigraphical age. This granite, like the Athis granite, metamorphoses the rocks of the Upper Briovdrien and not the basal rocks of the Cambrian of Normandy that uncom£ormably overlie it (Chauris et al. '956). The unconformity is a consequence of the Cadomian orogeny. The Cam- brian of Normandy is poor in fossils. In the 'Zone bocaine' the portion that directly overlies the Vire-Carolles granite is 12oo m thick. It contains, some 5oo m above the base, an oolitic limestone with Hyolithes spp. (F. Dord, in litt. and in the press) which the same geologist considers to be an equivalent of the Carteret or St Jean-de-la-Rivi~re limestones belonging to the Moitiers d'Allonne area, which begins 5 ° km to the north of the 'Zone bocaine'. The Carteret limestones contain not only Hyolithes sl0p., but also Archaeocyatha (Coscinocyathus corbicula Born and Proto- pharetra polymorpha Born), a trilobite Bigotina bivallata Cobbold, and stromatolites. These fossils represent a middle Lower Cambrian assemblage (F. Dord, in the press). The Cartaret limestones are preceded by some 5oo m of Cambrian shales and sandstones with Hyolithes spp. and 5oo m of ?Cambrian basal conglomerate.

Refef £1lce$ CHAURIS, L. DANGEARD, L., GRAII~OR, M.J. • DE LAPPARENT, A. F. '956. Les principaux batholithes granitiques du Bocage normand sont antdrieurs ~ la transgression cambrienne. C.R. Acad. Sci., Paris, 243, 77-9. DOR~, F. Age et position des calcaires de St. Jean-de-la-Rivi~re dans le Cambrien des Moitiers d'Allonne (Manche). Bull. So¢. gdol. Fr. [in the press]. GRAINDOR, M.J. & WASSERBURG, G.J. ,962 (see Item 4I). KAPLAN, G. & LRtrrW~IN, F. I963. Contribution ~ l'dtude g~ochronologique du massif graniti- que de Vire (Normandie). C.R. Acad. Sci., Paris, 256, 2oo6-8. STARIK, I. E. , 96 x. [Nuclear geochronology.] Moscow (Academy of Sciences) [In Russian]. [L. Cahen, F. Dord & A. G. Smith] 300 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. In view of the thickness of sediments below the fossiliferous beds, it is quite possible that all of the Lower Cambrian is represented. At present, however, it can be stated only that the adopted age of 553 m.y. is earlier than middle Lower Cambrian. L. Cahen & F. Dor6

Radiometric comment. Kaplan and Leutwein (I963) mention the possibility that the apparent ages of the biotite represent a late phase in a complex history, though they conclude that it is more likely that these ages represent the principal episode in the formation of the Vire-Carolles granite. The latter view is supported by the muscovite and biotite ages obtained on the contemporaneous Athls granite (see Item 4 I) and by the ages obtained on the presumably contemporaneous Chausey granite, nearly all of which are practically concordant with those obtained here (Graindor & Wasserburg 1962). The difference in age (c. 45m.y.) between the granite and the total-rock age for the pegmatite is not in itself unusual; it would, however, be impossible to reconcile it with the view that this pegrnatite is also Pre-Cambrian. But the pegmatite is not in contact with the Cambrian beds and may possibly be later than some or all of the Cambrian sedimentation; the age of this pegmatite is supported by that of a muscovite from a pegmatite near St Malo (Rb--Sr: 5o9 4- 11 m.y. ; Grain- dor & Wasserburg x962). Graindor (I957) mentions the possibility of two successive granites, one of them being 'post-Cambrian'. Ref~e//~8 GRAINDOR, M.J. i957 (see Item 41). L. Cahen Radiometric comment. That of Item 7 ° may apply to these results. A. G. Smith

(43) Metamorphic rocks and minerals from Rhode Island Formation ~/Carboniferous (Pennsylvanian) Narragansett Basin, Rhode Island, U.S.A. (a) 4I°35.7o'N, 7 I° I5"OO'W; (b) 41°33"8o'N, 7 I° i6"4o'w; (c) 4 I° 35"75'n, 7 I° 2I'66'w; (d) 4 I° 31.83'N, 7 I° 23.4I'W.

Radiometric age K-Ar ().p = 4"72 × IO-l°year-X; ite = 0"585 × to-X°Year-l)

K (%) Air corrn (%) 4°Ar*#°K Age (m.y.) Whole-rock samples (a) R-3917 Medium-grey slate 3.91 6 o'oi59 2534- x3 (b) R-392o Pale-grey, highly fissile slate 2"82 I3 o'oi44 23o4- I2 3"99 2 o'oi64 26o4- 13 (c) R-3818 Papery white slate ((~iil 4-07 2 o.oi66 2634- I3

Biotite concentrate: (d) B--38X7 From biotite-garnet-schist 3"30 8 o'oi74 2754- x5 B-3817 A As in B-3817, reconcentrated 6"43 9 o'oi55 2504- I2 Mean: [255 4- 7] m.y. Rb-Sr (it = I "39 × Io-ny ear-l) Rb S7Rb Sr SvSr* Age (m.y.) (ppm) (ppm) (ppm) (ppm) 8TSr*/SVRb 2 -= I'39 it = I'47 (d) B-3817A as above 666 I87 I4"9 o.682 o'0o369 26o [265] [251 ]

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Stratigraphical age. The Rhode Island Formation contains fossils of Allegheny aspect (Knox 1944) and metamorphism must thus be late Pennsylvanian or post-Pennsylvanian.

References FAUL, H. I96o. HURLEY, P. M., FAIRBAIRN, H. W., PINSON, W. H. & FAUR~, G. I96o. K-A and Rb-Sr minimum ages for the Pennsylvanian section in the Narragansett basin. Geochim. et cosmoch. Acta, 18, 247-58 . KNox, A. S. I944. A Carboniferous flora from the Wamsutta formation of south-eastern Massa- chusetts. Amer. o7. Sci. o42 , I3o-8. [E. H. Francis]

(44) Quincy granite Carboniferous (Pennsylvanian)]Devonian Swingle quarry, Massachusetts, U.S.A. [42° 15.3'1% 7 I° 1.8'w].

Radiometric age K-Ar (~B = 4"72 × Io-X°year-:; he = o'585 × xo-l°year-x) R-382I whole rock: K = 3"45%, air corm: 5%, 4°Ar*# °K = o'o178, age: 28om.y. The rock contains no mica, and since this reading is based on feldspar it is a minimum age only.

Stratigraphical age. The granite is believed to be of Mississipian (?) age because it cuts Devonian (?) and is unconformably overlain by Pennsylvanian rocks. The conglomerate at the base of the Pennsylvanian section of Rhode Island contains granitic waste.

R~ger/ge$ HURLEY, P. M. et al. I96o (see Item 43). [E. H. Francis]

(45) Drammen granite /L. Permian Road cutting near Skoglyst, Drammen, Norway [54 ° 44'N, Io ° 22'v.].

Radiometric age K-Ar (~# = 4-72 × IO-10year-X; ~ = 0-585 × Io-:0year -1) Biotite: K = 4-03 4- o'o4%, 4°At* = o.o8o ~ o.ooi ppm, 4°Ar*#°Art°t = 0.77 , 4°Ar*#°K = [o-oi63] , age: 259m.y. (Faul, Elmore & Brannock 1959) ; 259 ~ Iom.y. (Kulp 196o); 259 ± 7 m.y. (Kulp 196I). Owing to difficulties in obtaining a completely chlorite-free sample, the authors regard the figure obtained as a minimum age.

Stratigraphical age. The Drammen granite cuts beds of mid-Lower Rothliegende age [see stratl- graphical comment].

References FAOL, H., ELMORE, P. L. D. & BRANNOCK, W. W. I959. Age of the Fen carbonatite (Norway) and its relation to the intrusives of the Oslo region. Geochim. et cosmoch. Acta, I7, 153-6. KOLP, J. L. 196o. • 1961. [D. B. Smith] 302 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems Stratigraphical comment. This granite intrudes basalts and rhomb-porphyry lavas below which, at Semsvik, 19 km west-south-west of Oslo, are continental deposits containing plants and fresh- water fish and lameUibranehs. The plants, in addition to long-ranging forms, include the typically Permian Walchia and Callipteris, the Permian fresh-water shark Pleurocanthus, and the fish Megalich- thys which, according to Sherlock (I947) , died out in the Lower Permian. The non-marine lamellibranchs were identified as Palaeanodonta el. castor (Eichwald) and P. ? stegocephalum (Geinitz) by Dix & Trueman (i935) , who stated that the shells are almost certainly post-Stephanian, and are likely to be about mid-Autunian or slightly earlier. The remaining fossils found in these beds do not conflict with this opinion.

RefereTlceS DIx, E. & TRtmMAN, A. E. 1935. Non-marine lameUibranchs from the Upper Palaeozoic rocks of Sernsvik in Asker. Worsk geol. Tidsskr. 15, 23-32. HOLTEDAHL, O. (ed.) I96O. Geology ofaVorway. Oslo. 54 ° pp. SHERLOCK, R. L. 1947. The Permo-Triassic Formations. London (Hutchinson). 367 pp. D. B. Smith

(46) Oslo nordmarklte .[L. Permian Road cutting on Trondheimsveien near north-eastern city limits of Oslo, Norway [59 ° 59'N I I o oS'E].

Radiometric age (1) ~zsU-~°nPb (2 = 1 "54 × IO-l°Year-l) (as quoted by Aldrich et al. [1958]) (2) ~z~Th-z°aPb (2 = 4"99 × Io-ny ear-x) (as quoted by Aldrich et al. [1958])

U (ppm) Th (ppm) Pb (ppm) ~°4Pb/~°aPb ~°TPb/~°ePb 2°sPb/=°ePb Zircon 363 4- 4 f'388 4- 4 ~J'21.94- 0"5 0"0040 O"113 0"428 368 4-4 ~.3964-4 L20"94-O'5

Age (1) ~38U/~°ePb: 259am.y. (Kulp [1961 ] quotes 260 4- 5m.y.); (2) 132Th/2°sPb: 216am.y. The figure of 259m.y. obtained by the U-Pb method is regarded by the authors as a minimum. They regard it as 'closer to the truth' than that obtained by the Th-Pb method.

Stratigraphical age. The nordmarkite cuts beds of mid-Lower Rothliegende age (see stratigraphical comment).

References ALDRICH, L. T. et al. 1958 (see Item 186). FAUL, H., ELMORE, P. L. D. & BRANNOCK, W. W. 1959 (see Item 45). [D. B. Smith]

Stratigraphical comment. Although the age obtained by the U-Pb method is the same as that of the Drammen granite (Item 45), the authors think this may be a coincidence, and they say that in any case both ages are minima. The Oslo nordmarkite, which is generally regarded as older than the Drammen granite, intrudes, in addition to basalt and rhomb-porphyry lavas, unfossiliferous continental sandstones and conglomerates. Although at one time regarded as Downtonian, these beds are now correlated with similar beds which are closely associated at Semsvik (19 km west-south-west of Oslo) with Lower or Middle Rothliegende (Autunian).

R~re~8 HOLTEDAI-IL, O. 196o (see Item 45). D. B. Smith 303 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

~/g/775 (47) Butterly Dolomite L. Ordovician] U. Cambrian Oklahoma, U.S.A. [Precise locality not given.]

RadiometHc age K-Ar (2# = 4"72 X Io-l°year-1; he = 0"584 × Io-X°year -1) IcA 344 'illite': K ~- 5"84%, atm. 4°Ar = I3%, 4°Ar*/4°K = o'o3o2, age: 457m.y. 'Appears to be an excellent age determination'.

Stratigraphical age. Top of Cambrian (Butterly Dolomite).

Reference EVERNnEN, J. F. et aL 196 I. [J. w. Cowie]

Stratigraphical comment. The Butterly Dolomite (Butterly Formation) occurs in Oklahoma, U.S.A. and was named by Decker (i 939, P. 1317). It is a facies equivalent of the upper part of the Cam- brian Signal Mountain Formation and the lower part of the Ordovician McKenzie Hill limestones. The only fossils found in the Butterly Formation are silicified brachiopods from the lower part of the unit, which have affinities with Signal Mountain Formation faunas and indicate an Upper Cambrian age for the lower part of the Butterly Dolomite sequence. Eastwards the contact between the Butterly and McKenzie Hill formations rises progressively, so that dolomite beds to the east are facies equivalents of limestones to the west. The Signal Mountain Formation has an abundant Upper Cambrian fauna, of the Trempealeauian Stage, mainly near the base. The lower subdivision of the McKenzie Hill limestones is the Chapman Ranch Formation, which contains gasteropods and cephalopods of Lower Ordovician (Beekmantown) age. As no location is given by Evernden et al. (I96I), their stratigraphical age for the diachronic Butterly Dolomite sample cannot be checked and may not be at the top of the Cambrian. In the central and eastern Arbuckle Mountains of Oklahoma, the Cambrian-Ordovician boundary lies within the Butterly Formation. It also appears that the fossil evidence from the Oklahoma formations does not closely define the boundary between the Cambrian and Ordovician systems.

References DECKER, C. E. I939. Two Lower Palaeozoic groups, Arbuckle and Wichita Mountains, Okla- homa. Bull. geol. Soc. Amer. 5 o, 1317-18. Fm~DERm~ON, E. A. 1956. Cambrian of Oklahoma. In E1 Sistema Cambrico, su paleogeografta y el problema de su base. Int. geol. Congr. 2o(2), 483-5o8. J. W. Cowie

Radiometric comment. See Item 48. A. G. Smith

(48) Gros Ventre Shale M. Cambrian/M. Cambrian Wyoming, U.S.A.

Radiometric age K-Ar (2B = 4"72 × Io-l°year-1; 2e = o'584 × Io-l°year -1) K~, 26I 'illite' (less than 8/t) : K = 5"86%, atm. 4°Ar = 8%, 4°Ar*/4°K = o-o358, age" 53om.y. This result may be a fortuitous interplay of detrital argon and argon loss from small grains; however, ~ 259, 26% and 26I do illustrate the decreasing influence of pre-erosion argon as the grain-size decreases.

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Stratigraphical age. Base of Middle Cambrian.

Re, fence EVERNDEN, J. F. et al. I96I. [j. w. Cowle]

Stratigraphical comment. The Gros Ventre Formation of Wyoming has been subdivided into three units; the oldest unit--the Wolsey Shale---near the top yields trilobites of undoubted Middle Cambrian age. The Flathead Formation that commonly underlies the Gros Ventre Formation is also referred to the Middle Cambrian but is apparently unfossiliferous except for linguloid brachiopods (Lochman-Balk 1956, p. 593). The Cambrian sediments rest unconformably on Pre-Cam- brian rocks. Evernden et al. (1961) gives its stratigraphical age as 'Base of Middle Cambrian'; this cannot be interpreted, without further palaeontological evidence, as indicating derivation from the earliest Middle Cambrian rocks. The sample age presumably fails within the Middle Cambrian.

References LOCHMAN-BALK, C. 1956. The Cambrian of the Rocky Mountains and southwest deserts of the United States and adjoining Sonora province, Mexico. In E1 Sistema Cambrico, su paleo- geograffa y el problema de su base. Int. geol. Congr. ~,o (2), 592-622. WILMARTH, M. G. 1938. Lexicon of geologic names of the United States. Bull. U.S. geol. Surv. 896, PP. 738 , 883. J. w. Cowie

Radiometric comment. The 'illite' used for most age measurements is usually a concentrate of the fine-gralned components of a sedimentary rock: predominantly clay minerals and micas. The fine-grained fraction will normally contain several different types of potassium-bearing minerals, each of which may have a different origin: (I) detrital, derived from a pre-existing terrain; (2) syngenetic, formed in situ, at the time of sedimentation; (3) diagenetic, formed in situ, at some (unknown) time after sedimentation. A large proportion of inherited detritus may give anomalously high K-Ar 'ages'; similarly, considerable diagenetically produced material may give anomalously low K-Ar 'ages'. An additional complication is that the finest material may lose argon by leakage. Thus, in general, the radiogenic Ar/K ratio of an 'illite' or fine-grained shale cannot be used to find an 'age' that is related to the time of sedimentation. At best ' "illite" ages' are imprecise order-of-magnitude guides to the time of sedimentation, and are unsuitable for use in the construction of a time-scale.

References EVERNDEN, J. F. et al. 196 I. HURLEY, P. M., BROOKINS, D. G., PINSON, W. H., HART, S. R. & FAIRBAmN, H. W. I96I. K-Ar age studies of Mississippi and other river sediments. Bull. geol. Soc. Amer. 72, 18o7-16. HF.EZEN, B. C., PmSON, W. H. & FAIRBAIRN,H. W. 1963. K-Ar values in pelagic sediments of the North Atlantic. Geochim. et cosmoch. Acta, 27, 393-9. HUNT, J. M., PINSON, W. H. & FAIRBAIRN, H. W. 1963. K-At age values on the clay fractions in dated shales. Geochim. et cosmoch. Acta, 27, 279--84. HOW~R, J., HURLEY, P. M., PINSON, W. H. & FAIRBAIRN, H. W. 1963. The dependence of K-At age on the mineralogy of various particle size ranges in a shale. Geochim. et cosmoch. Acta, 27, 4o5-1o. A. G. Smith

(49) Lower Greensand (Bargate Beds) L. Cretaceous/L. Cretaceous Stock Farm, Churt, Surrey, England. 305 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometri¢ age K-Ar (;tp ----- 4"72 × Io-l°year-a; ~ ---- 0"584 X xo-t°year -1) r~ 445 glauconite: K ----- 5"55%, atm. 4°At = I8%, 4°Ar*/4°K = o.oo658, age: x xom.y.

Stratigraphical age. Lower Cretaceous (Upper Aptian). Reference EWRND~N, J. F. et al. x96x. JR. Casey] Stratigraphical comment. A glauconitie sandstone firmly dated by ammonites as Upper Aptian, nutfieldensis Zone, subarcticum Subzone (see Casey I96X). The Bargate Beds of this region contain derived Upper Jurassic (mostly Oxford Clay) macrofossils, and it is possible that some of the glauconite has a similar origin.

Reference CASE,,', R. I96x. Stratigraphical palaeontology of the Lower Greensand. Palaeontology, Lond. 3, 487-62I. R. Casey

(5o) Lower Greensand (Hythe Beds) L. Cretaceous/L. Cretaceous Road cutting 4 miles north-north-east of tIaslemere Brook, Surrey, England.

Radiometric age K-Ar (2p -~ 4"72 × Io-X°year-X; ~ = o'584 × Io-X°year-1) 442 glauconite: K ----- 4"35%, atm. 4°Ar = 23%, 4°Ar*]4°K = o'oo699, age: xI5m.y.

Stratigraphical age. Lower Cretaceous (Lower Aptian).

Ref e?'en¢£ EVERND~N, J. F. et al. 196 i. JR. Casey]

Stratlgraphlcal comment.Glauconitic sandstone in Hythe Beds. The donor of the sample adds 'upper part' (Kirkaldy x963, p. I44). The Geological Survey m 6-in. map shows the locality to embrace high (but not highest) Hythe Beds. Regional knowledge of Hythe Beds zonation indicates Lower Aptian, bowerbanki Zone (i.e., topmost Lower Aptian).

Refirence Kmg~T.DY, J. F. x963. The Wealden and marine Lower Cretaceous beds of England. Proc. Geol. Ass., Lond. 74, 127-46. R. Casey

(5x) Gault L. Cretaceous]L. Cretaceous. Half a mile east of promenade, Folkestone, Kent, England.

Radiometric age K-At (~p = 4"72 × IO-l°year-I; ~ = 0"584 × IO-X°Year-x) g.A 282 glauconite: K = 6"52%, arm. 4°At ~ 2I%, *°Ar*/4°K = o'oo564t, age: 94m.y. 'Appears to be slightly young' (Evernden et al. 196 I). t Written communication, Evernden x964, 306 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical age. Lower Cretaceous (Middle Albian).

Reference EVERNDEN, J. F. et al. 196 I. [R. Casey]

Radiometric comment. The locality is a sea-cliff, and the pyritic substratum of the sampled bed contains unusual decomposition-products, mainly chlorides, which are due to exposure to salt- water spray (Radley I929, p. 145 ). R. Casey

Stratigraphical comment. The bed sampled is in glauconific clays at the base of the Gault, firmly positioned in the type-section of the English sequence as basal Middle Albian. This horizon was formerly included in the mammiUatum Zone (to which it is referred by Kirkaldy 1963, p. 144 ) but is now considered to be part of the dentatus Zone (eodentatus Subzone) (Casey x96I , p. 498).

References CASEY, R. 1961 (see Item 49). KIRKALDY, J. F. x963 (see Item 50). RADLEY, E. G. I929. The preservation of pyritised and other fossils. The .Naturalist, April-June 1929, 143-6; I67-73; I96-2o2. R. Casey

(52) Portland Beds (Portland Sand) U. Jurassic/U. Jurassic Okns quarry, Swindon, Wiltshire, England; I5 ft below ground level.

Radiometri¢ age K-Ar (;tp = 4"72 × Io-l°year-1;/]e = 0"584 × IO-l°year-1) KA 27 ° glauconite: K = 6"64%, atm. 4°Ar = 7%, 4°At*# 0K = 0"00753, age: 125m.y. 'Appears to be too young for stratigraphic age. Burial history unknown to us' (Evernden et al. I961).

Stratigraphical age. Upper Jurassic, glauconitic bed, Portland Sand (Lower Portlandian; gorei Zone).

Reference EVERNDEN et al. I961. JR. Casey & M. K. Howarth]

Stratigraphical comment. Sample was obtained from a limestone with glauconite pellets. According to Arkell (1936 , p. 5o7), this horizon yields the zonal ammonite Glaucolithites gorei. Mikhailov (1957) equates the gorei Zone with the lower part of the Zone of Virgatites rosanowi (in the upper part of the Lower Volgian) of the Moscow basin.

References ARKELL, W.J. 1936. The oTurassic System in Britain. London (Oxford University Press). MIKHAILOV, N. P. 1957. Zoni podmoskovnogo Portlanda. Bull. 8oc. Nat. Moscou (Otdel Geol.), 32 (5), I44-59. R. Casey 307 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

(53) Sylvinlte L. Permian]L. Permian Verkhnekamensk Formation, Solikamsk, U.S.S.R. (stratum 'B', Upper Kama Formation) [59 ° 40'N, 560 45'P].

Radi~metriv age K-Ar (~p = 4"7 × Io-t°year-a; ~.e = 0"55 x IO-t°year-1; '°K/K = x "2 × IO-' g/gK) ' °K X I O5 Age SyIvine K (%) 'OAr (ppm) attn. 'OAr (%) (g/g) '°Ar*/'°K (m.y.) Sample x 5 x. 7 o. 885 o. 3 6-20 o.oi42 ) 236 ([226] unrecrystallized o. 841 o. 1 6-20 o.oi35 [216] Sample 2 5 x. 3 o. 6 I8 4 6"16 0"0100"~ { 162]" recrystallized o. 581 2 6.16 0-0o92 3 I65 153]" t Calculated by M. H. Dodson from author's data, using kS = 4" 72 × Io-t°year-~ 3~ = 0.584 × I o -x°year-1. K-Ca 4°Ca* (ppm) 4°Ca*/Cat°t Age (m.y.) Sample I 7"55 o.I 4 241 [238] Sample 2 7"47 0"030 241 [238]

Age: 24 ° 4- 5 m.y. Kulp ( 1961 ) The authors classify the two samples on the basis of their appearance. They regard the results as signifying that radiogenic calcium remained in the rock during recrystallization, whereas the argon escaped. Kulp (I 96 I, p. I i I O) believes that the age should be regarded as a minimum.

Stratigraphical age. Kungurian (uppermost Lower Permian).

References KULP, J. L. i96o. i96i. POLEVAYA, N. 1., TITOV, N. E., BELYAEV, V. A. ~z: SPRINTSSON, V. D. I950. Application of the Ca method for the absolute age determination of sylvites. [Translation] Geochemistry, I958 (8), 897--906" [D. B. Smith & M. H. Dodson]

Stratigraphkal comment. The Verkhnekamensk (also known as the Verkhne-Kamskoye or Upper Kama) Formation of the Solikamsk area is the main salt-bearing horizon of the type-area of the Permian system, and it forms the middle lithological division of the Kungurian Stage. Bed 'B' is composed of variegated sylvinite, and lies 25 to 3om below the top of the sylvinite zone. It is about 3oom below the top and about 7oom above the base of the Kungurian beds. Beds between the 'B' bed and the base of the Kungurian consist of halite (250 to 4oom) overlying alternating clay and anhydrite beds. Annual (?) banding is common in the salt and parts of the underlying beds, and such banding should yield a reasonably accurate age for the Artinskian-Kungurian boundary. Insufficient information is available for this to be done yet, but from general considerations the 'B' sylvinite bed is probably of high mid-Kungurian age.

Reference IVANOV, A. A. 1937. The Solikamsk district. In The Permian excursion, northern part. (ed. Nalivkin, D. V.), pp. 95-I Io. Leningrad & Moscow (Seventeenth International Geological Congress publication). D.B. Smith

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(54) Ripley Formation U. Cretaceous/U. Cretaceous Gulf Coast, U.S.A.

Radiometric age K-At (~p = 4"72 x Io-S°year-4; he = o'584 × Io-X°year-1)

K (%) atm. 'OAr (%) *°Ar*/4°K Age (m.y.) KA 152~j fglauconite } 4"41 65 o.oo4I 5 7° [69" 5] .J (concentrate from v.A 439 | ] glauconitic 5" 54 27 0.004o8 69 [68.5] Lsandstone)

Age: [69]m.y.

Stratigraphical age. Upper Cretaceous (Maestriehtian).

Refgrence EWR~m~, J. F. et aL 196t. [R. Casey]

Stratigraphical comment. The locality and horizon are too vague for detailed stratigraphical analysis. In the Gulf Coast region generally, the Ripley Formation rests on the Selma Chalk and is overlain by the Owl Creek or Prairie Bluff formations. Stephenson et al. (i942 , table) show the Selma Chalk as Campanian (perhaps reaching upwards into basal Maestrichtian locally), with the Owl Creek and Prairie Bluff formations well up in the Maestrichtian. In Georgia, Alabama, and Tennessee the base of the Ripley Formation lies in or just above the Exogyra cancellata Zone, which yields Belemnitella americana (Morton) (Stephenson 1933). Jeletzky (i962 , p. 16o) considers this belemnlte to belong to the Upper Campanian, perhaps the early part of the Upper Campanian, in his scheme of classification (Jeletzky 195 i). This classification fixes the base of the Maestrichtian on the entry of the genus Belemnella. Some authors take the view that the use of this criterion results in an unwarranted enlargement of the 'Syst6me Maestrichtien' of Dumont (see Hofker 1962, p. I o58). Thus in the European scheme the Ripley seems to straddle the boundary between the Campanian and the Lower Maestrichtian (sensu Jeletzky), but to lie mostly in the latter stage.

References HOFKER, J. 1962. Correlation of the Tuff Chalk of Maestricht (type Maestrichfian) with the Danske Kalk of Denmark (type Danian), the stratigraphic position of the type Montian, and the planktonic foraminiferal break, o7. Paleont. 36, lO51--89. JELETZKY, J. A. 195 I. Die Stratigraphie u nd Belemnitenfauna des Obercampan und Maastricht Westfalens... Beih. geol. oTb. z, 1-I42. I962. Cretaceous belemnites of New Jersey. In Richards, H. G., Cretaceous fossils of New Jersey. Bull. N.oT. Dep. Conserv. econ. Develop. 6I (2), 139-61. STEPHENSON, L. W. 1933. The zone of Exogyra cancellata traced twenty-five hundred miles. Bull. Amer. Ass. Petrol. Geol. x7, 1351-61. KINC, P. B., MONROE, W. H. & IMLAY, R. 1942. Correlation of the outcropping Cretaceous formations of the Atlantic and Gulf Coastal Plain and Trans-Pecos Texas. Bull. geol. Soc. Amer. 54, 435-48. R. Casey

(55) Shinkolobwe urani~te ]late Pre-Cambrian Shinkolobwe Mine, Katanga, Congo Republic [26 ° 33' E, I I ° 03' S]. 309 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

xT/6m$ Radiometric age U-Pb (;t[238U] = I "5369 × lO-l°year-~; ~[2ssU] = 9"7216 × Io-l°year-1) ; 23sU/235U = I37"7; common lead corrected with lead of the following composition: x; i8.~6; I5.9o; 38.49 " Age ---- 62o a 4- 2om.y. (Cahen et aL I96I ). This age is yielded by 9 concordant determinations on 4 different specimens, and it is also the 'best' age of I2 discordant determinations on 7 different specimens. It is supported by 4 determinations on Kalongwe uraninite and I on Luishya uraninite.

Stratigraphical age. The Shinkolobwe, Kalongwe, and several other uranium mineralizations of Katanga post-date the major thrusting of the Katangan orogeny. The thrusting itself post-dates the major folding. The uranium mineralization is, however, followed by other mineralizations and by weak tectonic movements. Though post-dating the last important episode of the Katangan orogeny, the uranium mineralization can therefore be considered as linked with the last episodes of the orogeny that involves the Kundelungu, Mwashya, and Roan of Katanga.

Ref~re~e$ CAreeN, L., PASTEELS, P., LEDENT, D., BOURGUILLOT, R., VAN WAMBEKE,L. & ]~BERI-IARDT, P. 196 i. Recherches sur l'ftge absolu des mindralisatlons uranif+res du Katanga et de Rhod~sie du Nord. Ann. Mus. Afr. centr. (Sdr. in-8, Sci. gdol.), 4 x, 1-53. DVRRIKS, J. J. & OOSTERBOSCH, R. I958. The Swambo and Kalongwe deposits compared to Shinkolobwe. Contribution to the study of Katanga uranium. Proceedings of the Second U.N. International Conference on the Peaceful Uses of Atomic Energy, Geneva, 2, 663-95. & V~s, J. F. I955. Le glte d'uranium de Shinkilobwe; 6tat actuel des connaissances du point de rue gfiologique et mdtallog~nique. Actes de la Conf3rence internationale pour l'utilisation de lYnergie atomique ~ des fins pacifiques, Gen~ve, ao~t x955, 6, Io8-44. [L. Cahen]

Stratigraphical comment. This evidence has been used to place a limiting date to the base of the Cambrian by Davidson (I959), Holmes (I959), Cahen (I96o, I96I) and Ca_hen et aL ([96z); it has also been discussed by Wetherill (I96o). The argument is as follows (Cahen et al. I96x): With the possible but improbable exception of a few hundred feet at the top which have not yet been recognized in the folded and mineralized area, the entire Katangan succession is older than 62o ± 2o m.y. The sediments appear not to have been deposited much earlier than the orogenesis for the first phases of this orogeny were active during the deposition of some of the Kundelungu (Upper Katangan) beds, and the ultimate phases are contemporaneous with the dated mineralization. In some of the Upper Kundelungu beds, which are certainly older than 62o 4- 2om.y., traces of life in the form of microfossils (protozoans and algae) and stromatolites have been observed, and the facies of the beds is perfectly suitable for the preservation of fossil remains of stratigraphical significance. The absence of a Cambrian fauna together with the preservation of forms that exist in the Pre-Cambrian is an argument in favour of a Pre-Cambrian age for these beds. It is thus unlikely that the Lower Cambrian fauna developed earlier than c. 62o 4- 2om.y. Davidson (I959) coupled this argument with K-Ar results from the U.S.S.R. to place the base of the Cambrian at about 6oom.y. Holmes linked it with evidence from Australia, and Cahen (I96I) with other evidence from Africa. Wetherill (i 96o), in his criticism, though agreeing that this is the best evidence given by Holmes (1959), stated (p. 35) that 'the evidence is obviously not clear-cut, in view of the dubious status of Precambrian palaeontology and the uncertainty in the inference that the uranium mineralization does not greatly post-date the Kundelungu sedimentary rocks'. This argument rests mainly upon negative evidence (the absence of Lower Cambrian fossils). In addition to the details given above, there are the following facts: (a) the entire Katangan succession is younger than c. i r4om.y. (syntectonic events of the Kibaran upon which the Katangan rests unconformably (Monteyne-Poulaert & Cahen I964) ; and 3zo Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(b) the same line of evidence can be based on the similar situation in Lower Congo, where a late syntectonic event of the West Congofian orogeny is 6x 5 4- i8m.y, old (Cahen et aL I963).

Ref£rence$ CArtoN, L. z96o. I96x. Review of geochronological knowledge in middle and northern Africa. Ann. N.Y. Acad. Sci. 9x, 535-67. et al. I96I (see above). ~, D~THAL, J., I_~D~NT, D. & REINnARZ, M. I963. L'~ge des migmatites de Boma et de l'orogen~se Ouest-Congolienne. Indications prdliminaires sur l'~tge des formations mayum- biennes et ant6rieures. Ann. Soc. g~ol. Belg. 86, B229-269. DAVIDSON, C. F. I959. How old is the Cambrian System? Nature, Lond. x83, 768-9. HOLMES, A. ~959. MONa~Y~E-POULA~RT, G. & CArtoN, L. 1964. Ages de granites pegmatites et filons de la Chalne Kibarienne au Katanga. Rapp. Mus. Afr. eentr. (section de g~ol.), x963. WEa'HFPaT L, G. W. I96O. Age of the base of the Cambrian. Nature, Lond. x87, 34-5. L. Ca-hen

Radiometric comment. Not all the uraninite at Shinkolobwe and in other Katanga deposits is 62o 4- 2om.y. old. An older generation, at least 67om.y. old and probably c. 72om.y. old, appears to exist and to have been reworked during the major tectonic episode at 62o 4- 2om.y. A younger generation, 52o q- 2om.y. old, entirely post-tectonic, exists both in Katanga and in Northern Rhodesia. Refe?'~nc$ CAHEN, L. et al. i96i (see above). L. Cahen

(56) Upper Greensand L. Cretaceous/L. Cretaceous Coast near Lyme Regis, Dorset, England.

Radiometric age K-At (~B ---- 4"72 × Io-l°year-1; he ~--- 0"584 × Io-l°year -1) KA I86 glauconite (concentrate from glauconitic sandstone): K = 4-98%, atm. 4°Ar ---- 22%, 40Ar./40 K _ o" oo576, age: 96 m.y.

Stratigraphical age. Lower Cretaceous (Upper Albian).

Reference EVERND~N, J. F. et al. I96I. [R. Casey]

Stratigraphical comment. 'Upper Greensand' is an omnibus term for various glauconitic sandy beds above the Gault. In the Lyme Regis area the 'Upper Greensand' comprises mostly Upper Albian (e.g., Cowstones and Foxmould) but perhaps also a little basal Cenomanian in the highest beds (Chert Beds). The source of the sample is in range basal Upper Albian-basal Cenomanian. R. Casey

(57) Emseher U. Cretaceous/U. Cretaceous Core from depth of 7 x x m, near Hanover, Germany.

3II Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometric age K-Ar (2~ = 4"72 × •o- °year-a; ~ = o-584 × xo-X°year-x) 298 glauconite (concentrate from glauconitic sandstone): K = 3'48%, atm 4°At = 32%, 4°Ar*/4°K = o.oo518, age: 87 [86"5]m.y.

Stratigraphical age. Upper Cretaceous (Coniacian).

Reference EVZaND~N, J. F. et al. x961. JR. Casey]

Stratigraphical comment. This item is noteworthy because of the Coniacian age of the sample, though there is no published information to say how the date was derived. R. Casey

(58) Bochumer Greensand U. Cretaceous/U. Cretaceous Near Herne [Miiuster Basin], Germany.

Radiometric age K-Ar (2p = 4"72 × Io-l°year-X; 2e = o'584 x xo-t°year -1) KA 3O6 glauconite (concentrate from glauconitic sandstone): K = 6"54%, atm 4°Ar = I7%, 4°Ar*/4°K = o'oo5oo, age: 84 [83"5]m.y.

Stratigraphical age. Upper Cretaceous (Middle Turonian).

Reference EV~rtr~DEN, J. F. et al. 196 I. JR. Casey]

Stratigraphical comment. The Bochumer Greensand of the Miinster basin is roughly equivalent to the English Middle Chalk Zone of Terebratulina lata. Details of stratigraphy and fauna supporting its Middle Turonian dating are given in B~irtling (i92o).

Re~rence B~.RTLINO, R. I92o. Trausgressionen, Regressionen und Faziesverteilung in der Mittleren und Oberen Kreide des Beckeus yon Mtiuster. Z. dtsch, geol. Ges. 52, 161-217. R. Casey

(59) Soester Greensand U. Cretaceous/U. Cretaceous Core from well near Dortmund, Germany.

Radlomaric age K-Ar (;tp = 4"72 × Io-X°year-1; ~ = 0"584 × xo-a°year -x) g.~ 3o9 glauconite (concentrate from glauconitic sandstone): K = 6'24%, atm. 4°At = x7%, 4°Ar*#°K = o-oo47I , age: 79m.y. 'Appears to be too young' (see stratigraphical comment).

Stratigraphical age. Upper Cretaceous ('Cenomanian') (see stratigraphical comment). 3t2 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

Reference EVERNDEN, J. F. a al. 196 I. JR. Casey]

Stratigraphical comment. The Soester Greemand is Upper Turonian in age (B~irtling 192o, p. 2Ol) not Cenomanian. The radiometric age, though rather on the young side, is consistent with the value (84m.y.) obtained for the Middle Turonian Bochumer Greensand of the same general area (see Item 58). Rgfb'r6,?/ce B.aa~TLmO, R. I92O (see Item 58). R. Casey

(6o) Glauconltic sandstone, Germany L. Cretaceous/L. Cretaceous Core from 613m depth near Salzgitter, Germany.

Radiometric age K-At (~p = 4"72 × IO-l°year-1; ~ = 0"584 × IO-t°yea r-x) KA 279 glauconite (concentrate from glauconitic sandstone): K = 4"77%, arm. 4°At = 42%, 4°Ar*/4°K = o'oo614, age: Io2m.y.

Stratigraphical age. Lower Cretaceous (Aptian-Albian boundary).

Reference Ewm~EN, J. F. et al. 196 I. JR. Casey]

Stratigraphical comment. No data are available to show how the stratigraphical age was determined nor which scheme of zonal classification is used to fix the Aptian-Albian boundary. In Germany this boundary is generally placed lower than in Britain and France (see Casey 196I, p. 495)-

Reference CASE-,-, R. 196I (see Item 49). R. Casey

(61) Essener Greensmad U. Cretaceous/U. Cretaceous Core from well near Dortmund, Germany.

Radiometric age K-At (kS -----4"72 × Io-l°year-X; ;re = o'584 × to-×°yea r-t) KA 316 glauconite: K ----- 6.8o%, atm 4°Ar = 38%, 4°Ar*#°K = o'oo51 I, age: 86 [85.5]m.y.

Stratigraphical age. Upper Cretaceous (Lower Turonian).

Reference EVeRNDEN, J. F. et al. 196 i. JR. Casey]

Stratigraphical comment. The Essener Greensand is primarily Cenomanian, but it is a diachronous deposit and, as shown by Biirtling (192o , pp. 175, 2Ol), locally extends into the base of the 313 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tgms

Turonian. The radiometric result fits in well with the figure (84m.y.) obtained from the Middle Turonian Bochumer Greensand of the same general area.

Reference BXRTLINO, R. I92o (see Item 58). R. Casey

(62) Glauconltlc sandstone, Germany U. Cretaceous/U. Cretaceous Core from well at 5oom depth near Hanover, Germany.

Radiometric age K-Ar (;tp = 4"72 × IO-l°year-X; ~---= 0"584 X IO-a°year-1)

XA 315 glauconite (concentrate from glauconitic sandstone): K = 5.30%, atm. 4°Ar = 3O~/o, 4°Ar*/i°K = o-o0486 , age: 8x [81.5]m.y.

Stratigraphical age. Upper Cretaceous (Lower Campanian).

Reference Evv.m~o~N, J. F. et al. 196 I. [R. Casey]

Stratigraphical comment. This item is noteworthy for being fixed precisely in the stratigraphical column, though there are no published data for checking the age assignment. R. Casey

(63) Les tufs de Brassac U. Carboniferous/U. Carboniferous Brassac coal mine, Puy-de-D6me, France, at the --226m level in the west drivage and 5ore from the Bayard pit bottom.

Radiometric age Rb--Sr (~ -~ x.47 X Io-nyear -1) Biotite in rhyolitic tuff (M.240)

Age (m.y.) S'Rb (ppm) S'Sr* (ppm) STSr*/STSrt°t sTSr*/S'Rb $=1"39 )l=1.47 o o7 o.o8 Eo.oo4o 1 E 73J

(2) 50"5 "~ o'214"1~ 0.088 "4 [0.00422 ] [303] [2861 5I "oj o'214J o'o89J (3) 523i}5° : o'22o~o'224J o'o89J°'°9I "~ [0"oo438] [314] [297]

Mean age: [3o5 -b 7]m.y. (Jl = 1-39); 288 4- 8 [4- 6]m.y. (;t = 1.47 )

Stratigraphical age. The tufts are interstratified above the 'gros banc', which is of the same age as the base of the St Etienne Stage and is thus, according to Vandenburghe (x96I), at the base of the Upper Stephanian. 3x4 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

References BONHOMME, M., PHILIBERT, J., RoQuEs, M. & VIALETTE, Y. I961. Ages absolus dans le Vis6en et dans les Stdphanien du Massif Central fran~ais. C.R. Acad. Sci., Paris, 252, 3084-6. VA1WDENBURGHE, A. 1961. Contribution h la recherche d'une limite entre le St6phanien et l'Autunien. C.R. Acad. Sci., Paris, 25% 1 I72-4. [E. H. Francis]

Radiometrk comment. The very low ratio of S~Sr* to total S~Sr in this sample means that the age given will be very sensitive to changes in the isotopic abundance of SVSr in 'common' strontium. A change of 0.3% in this would lead to a change of about iom.y, in the age. Such a change might well be found necessary if whole-rock Rb-Sr measurements were made, and it is more likely to lead to a reduction in the age than to an increase. M. H. Dodson

Bonhomme et al. usually made two independent determinations of each of the STRb and sTSr* contents. For recalculation purposes, these have each been averaged, and only one age has been calculated from them. The authors used a more sophisticated statistical method to arrive at an age but, as can be seen above, there is no significant difference between the values obtained by different methods of calculation. A. G. Smith

(64) Veraya Tier Carboniferous/Carboniferous Dergunovka borehole, Dergunovka village, U.S.S.R. (Russian platform).

Radiometric age K-Ar (2p = 4"72 × Io-X°year-1; 2e = o'557 × Io-l°year-x) Glauconite: K = 5"29%, 4°Ar*#°K = o.oi86, age: 3o8 [294] m.y.

Stratigraphical age. The Veraya Tier is the lowest unit of the Moscovian Stage of the Russian Middle Carboniferous.

Reference POLEVAYA, N. E., MURINA, G. A. & KAZAKOV, G. A. I961 (see Item 2o). [E. H. Francis]

Radiometric comment. This appears to supersede the 255m.y. dating (Kazakov & Polevaya 1958 ) given by glauconite from the same horizon (see Item 16). E. H. Francis

(65) Paterson toseanlte U. Carboniferous/U. Carboniferous Lower Hunter Valley, New South Wales, Australia; grid reference: x-in. Military Map, Paterson 629, 695.

Radiometric age K-At ()l# = 4"72 × lO-l°year-1; 2e = 0"584 × lO-l°year-x) Biotite: K = I "343%, 4°Ar*# °K ----- o.o188, age: 298m.y.

Stratigraphical age. Given variously as 'Lower Kuttung' and Upper Carboniferous. 315 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

1gems Reference ~',VERNDEN, J. F. & RaCHAgDS, J. R. x962. Potassium-argon ages in eastern Australia. o7. geol. Soc. Aust. 9, x-49. [E. H. Francis]

Stratigraphical comment. Toscanite lavas occur in both the Lower Kuttung and Upper Kuttung of New South Wales, but the term Paterson toscanite seems to relate specifically to a flow forming a conspicuous marker-horizon near the top of the Upper Kuttung (David I95O, p. 318). This accords with Evernden & Richards's classification of this rock as Upper Carboniferous, but their further use of the term Lower Ifuttung is presumably an error, and is particularly confusing in view of their own age-determinations of two other toscanites (Item 66) which are certainly of Lower Kuttung age. Unfortunately, Evernden & Richards (I962) make no reference to yet another toscanite (Item 3o) dated as 278m.y. by Evernden et al. (I96I), though Kulp's (I96Z) description of this rock as uppermost Carboniferous suggests that it too might be Paterson toscanite. In the Booral area, about 2o miles north-east of Paterson, the correlatives of the Paterson toscanite--the Stroud Volcanics--are underlain by the Isaacs Formation containing Syringothyris bifida and other marine forms that may be Stephanian in age: the Booral Formation, still lower, contains Levipustula levis, indicating a Westphalian B to low Westphalian C age (Campbell I96I ).

Radiometric comment. The low potassium percentage is taken by Evernden & Richards to indicate a high degree of alteration, and the determination is therefore regarded as less valuable than those from other samples of toscanite from the older Lower Kuttung Series (Item 66).

References CAMPBFLr, K. S. W. I96I (see Item 30). DAVID, T. W. E. 195 o. The geology of the Commonwealth of Australia. London. E. H. Francis

(66) Lower Kuttung lavas Carboniferous/Carbonlferous Hunter Valley, New South Wales, Australia: (I) OA I20 32o 4 I' S, I5 I° 32' •; (2) OA X15 32° 4 I' S, X5 I° 3 I' E; (3) CA X4IH 320 38' S, X5 I° 29 ' ~; (4) OA I43H 32° 34' S, I5 I° 36' ~.

Radiometric age K-Ar (2# = 4"72 × Io-X°year-X; 2e ---- 0"584 × xo-l°year-i)

Mineral Weight (g) K (%) *°Ar*/4°K Age (m.y.) (I) GA I20 Lower Kuttung Biotite ('cfBerkley sample KA46X') 288 b toseanite (no further data given) (2) GA IX 5 Lower Kuttung Biotite o'5o4o 4"43 o.oi82 288 toscanite (3) GA I4In Hudsons Peak Hornblende o.5o99 o.74I o.o2o8 32I [326] andesite (4) GA I43u Martins Creek Hornblende o.4892 o.778 o.o2o 9 297 [328] andesite

Stratigraphical age. These Lower Kuttung rocks are listed above in stratigraphieal order; all are believed to lie below the Paterson toscanite, dated as 298m.y. (Item 65). The range 288 to 321 m.y. suggests a (?) Middle Carboniferous age. 316 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items ReJ~feng# EWm~D~N, J. F. & RaCHAPmS,J. R. x962 (see Item 65). [E. H. Francis]

Stratigraphical comment. Campbell (I96I) records Levipustula levis (indicating a Westphalian B or low Westphalian C age) from the Booral Formation, which by his correlation lies above the Lower Kuttung Lavas and is separated from them by the Karuah Formation. This implies an approximately Narnurian age for the lavas, which is in keeping with Evernden & Richards's assessment of them as (?) 'Middle' Carboniferous, though the Lower Kuttung is usually equated with the Upper Burindi as Vis~an in age (Osborne I95o ). R~fe~e$ CAMVB~LL, K. S. W. I961 (see Item 3o). OSBORNE, G. D. I95o. The structural evolution of the Hunter-Manning-Myall Province, New South Wales. Monogr. roy. Soc. .N.S.W. x, I-8o. E. H. Francis

(67) Granite (,,nn~med) L. Jurassic/L. Permian Road cutting on New England Highway, 23½ miles south of Tenterfield, New South Wales, Australia [29 ° 2o' s, x52° o' ~].

Radiometric age K-Ar (~p ~ 4.72 × Io-l°year-1; he -~ 0.584 × Io-l°year -1) Biotite: K = 6.66%, 4°Ar*#°K = o'oi48 , age: 238m.y.

Stratigraphical age. Middle [upper division of Lower] or Upper Permian. This is one of a series of granites, some of which intrude the Lower Permian Drake Series and are overlain by Triassic- Jurassic sediments. R~fence EWRNDEN, J. F. & I~CHARDS, J. R. i962 (see Item 65). [D. B. Smith]

Stratigraphical comment. This, like the Stanthorpe granite (Item 64), is one of the New England granites of northern New South Wales. These intrude folded Drake Series beds (? Artinskian to early Kungurian) and in parts of the complex are overlain by Lower Jurassic sediments. Because the intrusion of the granites and the Hunter-Bowen orogeny are associated in time, most of the granites are probably post early-Tatarian. See Item 69 for further discussion and reference. D. B. Smith

(68) Berkley latlte L. Permian/L. Permian American Creek quarry, Mount Kiera, New South Wales, Australia (approximately 5 o miles south-south-west of Sydney) [34 ° 26' s, x5 °0 5 I' ~].

Radiometric age K-Ar (~B = 4"72 × IO-l°year-1; ~e-~ 0"584 × Io-l°Y ear-x) Feldspar: K -- o. 885% , 4°Ar*]4°K = o.ox58 , age: 252 m.y. .Note: The Bombo [Bumbo] latite, which is older than the Berldey latite, gives an age of 244m.y. 3x7 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Stratigraphical age. The sample is from the uppermost flow of the Upper Marine volcanic sequence of the Illawarra coast. The latter is held to be of Middle [upper division of Lower] Permian or Upper Permian age.

Refg?'ence EVERNDEN,J. F. & RICHARDS,J. R. I962 (see Item 65). [D. B. Smith]

Stratigraphical comment. The Berkley latite is a terrestrial lava whose exact stratigraphical horizon is in doubt. This is because the lava lies in a contemporaneous washout in the uppermost part of the Upper Marine Series, and its time-relationships to the lavas of this series have not been established. However, on the field evidence quoted (Harper I916, p. 74) it seems certain that the Berkley latite is younger than the Cambewarra flow, the top of which is taken as the top of the Upper Marine Series and locally suffered erosion before the deposition of the Upper Coal Measures. The washout in which the Berkley latite lies is presumably due to this erosion; and beds filling it, both above and below the lava, are fresh-water deposits comparable with those of the Upper Coal Measures. Field relationships therefore suggest that the Berkley latite lies not in the Upper Marine Series, as stated by the authors, but slightly above the base of the overlying Upper Coal Measures. David (195o) follows Teichert (1941) in placing the base of these beds some distance above the Artinsldan-Kungurian boundary; if this is correct, the Berkley latite is of approximately low-mid to mid Kungurian age.

References DAVID, T. W. E. 195o (see Item 65). HARPER, L. F. 1916. Geology and mineral resources of the Southern Coalfield. Mem. geoL Sum. N.S.W. 7, 294-5. TElCHERT, C. x94 I. Upper Paleozoic of Western Australia: correlation and paleogeography. Bull. Amer. Ass. Petrol. Geol. 25, 371-415. D. B. Smith

(69) Stanthorpe granite U. Triassic/L. Permian Intersection of Liston-Rivertree road with Wylie Creek, near Stanthorpe, Queensland, Australia [28 ° 38' s, 1520 o8' E]. The site is about 12 miles east of Stanthorpe, across the New South Wales border.

Radiometric age K-At (2p = 4"72 × IO-x°year-a; 2e----0"584 × xo-X°Year-x) K (%) '°Ar*/'°K Age (m.y.) Biotite 6.75 o"oi4o 225 Hornblende I. 5 r 6 o. o 137 221 Age: 223 m.y.

Stratigraphical age. The Stanthorpe granite is one of the more northerly extensions from the New England granites of New South Wales. Its age is Middle or Upper Permian.

Re, fence EVemVoEN, J. F. & RmHAm~S, J. R. i962 (see Item 65). [D. B. Smith]

Stratigraphical comment. The intrusion of the Stanthorpe and other New England granites is believed to have followed the Hunter-Bowen orogeny, major phases of which preceded and followed the 318 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns deposition of the Upper Coal Measures (correlated tentatively with the Kazanian and early Tatarian stages). Beds cut by the granite were already folded, and range up to the Drake Series, which David (i95o) correlated with the Artinskian and early Kungurian. They are overlain locally by sandstones and shales of the Upper Triassic Bundamda Series. The granite is thus dated stratigraphically as post-early Kungurian, pre-Upper Triassic, but the inferred association of the intrusion with the Hunter-Bowen orogeny probably dates it as post-early Tatarian. A mid- to late-Tatarian age appears likely, but a post-Tatarian age is possible.

Rej~renee T. W. E. I95o (see Item 65). DAVID, D. B. Smith

(7 o) Boisdale I-Iills granite --/M. Cambrian Cape Breton Island, Nova Scotia, Canada [460 4'N, 60 ° 30'W].

Radiometric age (I) K-Ar ()l/~ = 4"72 X Io-X°year-a; 2e-----o'585 × xo-X°year-~) Biotite n3132: K = 3.69%, 4°Ar*]4°K = o'o349, age: 518m.y.

(2) Rb-Sr (;t = I "39 × I°-XlYear-a) S~Rb/Rb ---- 27"85 at. %, initial svSr/Sr = 7"02 at. %.

Rb Sr sTSr* Age (m.y.) (ppm) (ppm) (ppm) Rb/Sr 'TSr*/Sr sTSr*/S~Rb ~=I'39 ~=I'47 Biotite B3132 286 35"4 o'53 8. I O.Ol 5 o'oo654 470 [443] K feldspar F3132 263 43"3 o.51§ 6. i o.oi2 o'oo685 486 [49 I] [464] § Isotope-ratio analysis of unspiked sample. Age: 5oom.y. (see Radiometric comment).

Stratigraphical age. The sample, collected about one mile from a contact with Middle Cambrian strata, is from a granite regarded as intrusive (Hutchinson 1952, fig. I). On the evidence of analyses of biotite and potassium feldspar, the granite sample is thought to be clearly older than most of the other granites studied by Fairbairn et al. (196o) in Nova Scotia, which are 3oo to 4oom.y. old. As there is no major stratigraphical discontinuity between Middle Cambrian and early Ordovician in this part of Cape Breton Island, the granite may be as young as early Ordo- vician. It is believed that the Boisdale Hills include at least some granite that is associated with a pre-Devonian orogeny, possibly Taconic. The Middle Cambrian rocks are tentatively believed to be older than 500 m.y. Rg~reg/~e$ FAmBAmN, H. W., HURLEY, P. M., PmsoN, W. H. & CORMmR, R. F. I96o. Age of the granitic rocks in Nova Scotia. Bull. geol. Soc. Amer. 7 x, 399-413 . HUTCm~SON, R. D. 1952. The stratigraphy and trilobite faunas of the Cambrian sedimentary rocks of Cape Breton Island, Nova Scotia. Mem. geol. Surv. Can. 263. [J. W. Cowie]

Stratigraphical comment. The sample locality is less than a mile from the granite-sedimentary rock contact where the Middle Cambrian outcrop is given in the map legend (Hutchinson 1952, fig. I) as undivided Bourinot Group. This group is assigned (op. cit., p. Io) to the lower part of the Acadian or Middle Cambrian Series because a trilobite fauna corresponding in age to the Paradoxides oelandicus fauna of the European Middle Cambrian has been collected from a formation 319 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items within the group. The Bourinot Group is overlain conformably by the MacMullin Formation, which yields trilobites indicating the second of the Paradoxides zones of the early Middle Cambrian. The Middle Cambrian sediments of Cape Breton Island are overlain disconformably by Upper Cambrian strata with overlap. This disconformity could represent the interval during which the granite was intruded, but it is clear that further radiometric data are needed. J. W. Cowie

Radiometric comment. Kulp & Engels (i963) show that K-Ar and Rb-Sr mica ages are generally in close agreement when the physically determined half-life of S~Rb (4 = I "47 × I°-alyear-x) is used to determine the Rb-Sr age. When discordances occur, the K-Ar age is generally higher than the Rb--Sr age. This is explained by preferential leaching of STSr* from the mica by ground- water action, and its replacement by S~Rb, which reduces the radiogenic Sr]Rb ratio and lowers the Rb-Sr age. Moderate ground-water action may decrease the potassium and argon content of a mica, but it does not alter the radiogenic Ar/K ratio. These effects may explain the discordant ages of the Boisdale Hills granite. If so, the Rb--Sr age should be ignored and certainly should not be averaged with the K-At age to find a mean value. Since K-Ar ages are minimum, the age of the granite is at least 518m.y.

Rgference KULV, J. & ENGF.LS, J. I963. Discordances in K-At and Rb-Sr isotopic ages. In Radioactive dating. Vienna (International Atomic Energy Agency), pp. 219-38. A. G. Smith

(71) Granite, Billlton, Indonesla Jurassic/U. Triassic Island of Billiton, Indonesia [3 ° o's, io7 ° 4o'F.].

Radiometric age K-At (2t = 5"3 ° × IO-l°year-1; ~ = 0"585 × lO-l°year-1) Biotite B-36IO: K = 4" I8%, 4°Ar*#°K = O.Olii, age: I8O 4- 5re.y.

Eight different ages have been obtained for this tin granite on Billiton and Singkep islands, Indonesia. All are between io5m.y, and i75m.y. , i.e., lower than the age obtained from K-At determination on biotite, except for an age of 23om.y. obtained from an RaD determination on separated zircon (for list, see Schiirmann et al. I96O , p. lO3). This RaD age is stated to be too high because of probable loss of radon (Schiirmann et al. 1956, pp. 323-5). The biotite age quoted here is the only one considered reliable by Holmes (1959, p. 2Ol) and Kulp (1961 , p. II I3) , who both accept I8O 4- 5 m.y.

Stratigraphical age. The age of the tin granite is close to the Trias-Jurassic boundary, for Triassic fossils have been metasomatized by the intrusion, and the granite occurs as boulders in Jurassic sediments (Schiirmann et al. 1956, p. 3 I4).

Re~rences HOLMES, A. 1959. HURLEY, P. M. et al. 1958. Variation in isotopic abundances of strontium, calcium and argon, and related topics. Sixth Annual Progress Report, Department of Geology and Geophysics, Massachu- setts Institute of Technology. Kuz.P, J. L. 196I. SCn~RMANN, H. M. et aL 1956. Second preliminary note on age determinations of magnmtic rocks by means of radioactivity. Geol. en Mijnb. 18, 3 I2-3o. et al. 196o. Fourth preliminary note on age determinations of magmatic rocks by means of radioactivity. Geol. en Mijnb. ~2, 93-IO4. [M. K. Howarth]

320 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

(7 2) Glauconltlc sands, Moscow t U. Jurassic/U. Jurassic Egorev deposit, near Moscow, U.S.S.R. [55 ° 45'N, 37 ° 37'~].

Radiometri¢ age K-At (2# = 4"9 × Io-X°year-X; 2e = o.6o2 × Io-l°year-1) Glauconite: K = 5"23%, arm. 4°Ar --, 4°Ar*#°K = o.oo8o, age: x3o (2e/2# ----- o'I25); I39 (/re/A# =o'xI7); [I32]m.y. (see radiometric comment below); I344-I3m.y (Kulp I96I, p. I113) ; 141 + 7m.y. (Kulp I96O , p. 22).

Stratigraphical age. Horizon of glauconific sandy clays underneath phosphorites. Kachpuritesfulgens Zone, base of Upper Volgian.

References KAZAKOV, G. A. & POLEVAYA, N. I. I958 (see Item 12). KuLe, J. L. x96o. i961. [M. K. Howart~

Radiometric comment. A figure of o .0077 for the 4°Ar*#°K ratio is probably the most reliable, since it is the latest (Polevaya, Murina & Kazakov 1961 , p. 304). It gives an age of I27m.y. with the constants adopted for this Symposium.

Reference POLEVAYA, N. I., MURINA, G. A. & KAZAKOV, G. A. 1961 (see Item 20). M. H. Dodson

(73) Glauconitic sandstone, Hanover U. Jurassic/U. Jurassic Hanover, Germany [520 23' N, 9 ° 44' w].

Radiometric age K-At (2#----4"72 × Io-l°year-X; 2e = 0"584 × Io-l°year -1) Glauconite: K = 6.38%, atm. 4°Ar = I3%, 4°Ar*#°K-----0-00842, age: I39m.y. (138 4-4 adopted in Kulp 1961 , p. i I I3).

Stratigraphical age. The specimen is from a core from a well near Hanover at a depth of 24 TM in Mfinder Marls. It is said to be Upper Portlandian, but the Mfinder Marls extend from the mid- point of the Portlandian to the top of the Lower Purbeckian. This is said to be an excellent age- determination because it agrees closely with the 'control ages' given by intrusions.

Rgffff ences EVEm~D~N, J. F. et al. 196 I. KusP, J. L. I96 I. [M. K. Howarth]

(74) [Incorporated in Item 52]

(75) Shasta Bally bathoHth L. Cretaceous/M. Jurassic One mile north of Ono, Shasta Co., California, U.S.A. [c. 4I°~2o'N, 122 ° 2o'w]. t This determination may correspond to the second value given in Item 322. 32I M Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

Radiometric age K-Ar (;tp = 4"72 × 'o-a°year-a; ire = o'557 x IO-l°year-1) Biotite from quartz-diorite: K = 6"25%, atm. 4°Ar = 9%, 4°Ar*# °K = o'o°77I, age: I34 [I27]m.y. (I27 4- 4m.y. [Kulp 1961 , p. Xli3] corrected for ~ = 0"584).

Stratigraphical age. The Shasta BaUy batholith was emplaced during the Nevadan orogeny. It is directly overlain by strata with a Lower Valanginian fauna, and 13 miles to the south-west these overlie the Knoxville Formation, which yields Middle Tithonian ammonites. This intrusion and the Nevadan orogeny are pre-Knoxville Formation and post-Lower (? and Middle) Kimmerid- gian, for the Mariposa Slate contains ammonites of Kimmeridgian age and is violently deformed by the Nevadan orogeny. This orogeny can be dated accurately, therefore, as Lower Tithonian (= Upper Kimmeridgian) and perhaps part of the Middle Kimmeridgian. This is the age of the Shasta Bally batholith, and is an example of remarkably accurate stratigraphical dating (Arkell 1956, pp. 551-4)- The stratigraphical evidence has also been interpreted (e.g., by Faul I96O, p. 639) as indicating that the batholith was emplaced during the time represented by the unconformity between the Knoxville Formation and the Lower Cretaceous beds. This would imply that the batholith belonged to the Diablan orogeny, and would date it as Upper Tithonian or Berriasian. This seems much less likely than a Nevadan origin and a pre-Knoxville Formation age for the batholith, because the Nevadan orogeny is pre-Knoxville and alters and folds only beds older than the Knoxville Formation.

References ARV,aCLL, W.J. i956. Jurassic geology of the world. Edinburgh & London (Oliver & Boyd). CURTIS, G. H., EVERND~N, J. F. & LIPSON, J. I958. Age determination of some granitic rocks in California by the potassium-argon method. Spec. Rep. Calif. Div. Min. 54. FAUL, H. x96o. KULP, J. L. I961. [M. K. Howarth]

Additional stratigraphical comment. It is agreed with Albers (I964) that the age-determination of 97m.y. by the lead-alpha method reported by Kinkel, Hall & Albers (1956) and the lead-alpha ages of 81 m.y. and IO1 m.y. reported by Jaffe et al. (1959) are incompatible with the geological evidence. On the other hand, the recalculated K-Ar date of 127 m.y. obtained by Curtis, Evernden & Lipson (x 958) has been accepted as a valid datum relevant to the Jurassic-Cretaceous boundary. The stratigraphical age-limits accepted for this batholith by Kulp (1961) are post-Kimmeridgian and pre-Valanginian. Howarth (this Symposium) believes that this pluton was emplaced during the Nevadan orogeny, more specifically during the Lower Tithonian. On this reckoning the 127 m.y. value is anomalous, being more appropriate to an horizon near the base of the Cretaceous. The alternative interpretation of the stratigraphical and palaeontological evidence given below is compatible with an early Cretaceous age for this batholith. Data for setting the lower age-limit of this batholith in stratigraphical terms are given by Albers (i964). The reasoning runs as follows: apophyses of the Shasta Bally batholith cut the Mule Mountain stock, and this stock in turn crosscuts folded schistose Copley greenstone and Balaklala rhyolite. The youngest formation in the area affected by the folding is the Potem Formation, of Middle Jurassic (Bajocian) age. Hence, the Mule Mountain stock and the Shasta Bally batholith are post-Bajocian. The batholith is overlain by conglomerates, sandstones, and mudstones included in the Rector and Ono formations of Murphy (1956) (----lower part of the Budden Canyon Formation of Murphy, Peterson & Rodda [1964] ). At the base of the upper part of the sequence is the Hert- leinites aguila Zone, considered to be of late Hauterivian age; the lower part has yielded fossils of the ill-defined 'Hamlin-Broad' Zone, thought to be of late middle or late Hauterivian age (Imlay 196o). Previous reference of these beds to the Valanginian was b,',.sed on misidentification of the 322 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems bivalves Inoceramus and Aucellina as Aucella [Buchia] and of the ammonite Hertleinites as Neocras- pedites (Imlay I959, 196o ). Even a Hauterivian date may be too old for these ammonites. The early Cretaceous ammonite faunas of the Pacific Coast region have a provincial aspect and exact correlation with the European sequence is still tentative. The known ranges of internationally significant ammonite genera in the 'Hamlin-Broad' and H. aguila Zones are as follows:

'Hamlin-Broad' Zone H. aguila Zone Crioceratites Crioceratites Hauterivian-Barremian Hop locrioceras Hoplocrioc eras U. Hauterivian-Barremian Acrioceras U. Hauterivian-L. Aptian Aspinoceras U. I-Iauterivian-L. Barremian Anahamulina U. Hauterivian-Barremian Shasticrioceras Shasticrioceras Hauterivian-Barremian Pseudothurmannia ? U. Hauterivian-Barremian Simbirskites Simbirskites ? Hauterivian-L. Barremian

This analysis offers for both zones a choice between Upper Hauterivian and Lower Barremian. A Hauterivian age for these horizons was preferred by Imlay on the grounds of similarity of Hertleinites to the 'late Hauterivian genus Craspedodiscus' and because of the belief that Simbirskites was primarily a Middle Hauterivian genus. It is true that the type-species of Craspedodiscus (C. discofalcatus Lahusen sp.) and of Simbirskites (S. decheni Roemer sp.) have been assigned to the Upper Hauterivian (e.g., Wright 1957) and that this age-assignment accords with Spath's (1924) interpretation of the succession at Speeton, Yorkshire. However, in the critical area of Ulyanovsk (formerly Simbirsk), in the Volga Basin (not Siberia), these two species characterize the Lower Barremian (see Luppov & Drushchitz I958, pl. xlii) and in the Russian platform region S. decheni is the index-fossil for this part of the sequence (Gerasimov et al. 1962 ). Owing to the fact that the classic sections of the Hauterlvian and Barremian stages lie in the Tethyan realm and have a different sequence of ammonites from that found in the Boreal realm, correlation of these northern regions with the standard succession is not straightforward. Moreover, opinions have differed as to the position of the Hauterivian-Barremian boundary in the type-regions of Switzer- land and France. Overlap between the two realms occurs in the Caucasus and the Crimea. In the Crimea, Craspedodiscus discofalcatus is found in the Lower Barremian with the exclusively Barremian group of Wicklesia pulchella (d'Orbigny) and with forms of Pseudothurmannia attributed (wrongly, judging by the single example illustrated) to P. angulicostata (d'Orbigny) (Drushchitz & Kudryavtseva 196o). It is not improbable, therefore, that the current Russian practice of including the decheni Zone in the Barremian is in line with the decision taken on the Hauterivian- Barremian boundary at the Lyon Colloquium (Rat 1963). Considering that Simbirskites broadi Anderson, a co-index-fossil of the 'Hamlin-Broad' Zone, is an analogue ofS. decheni, this zone and the overlying aguila Zone may well be Lower Barremian rather than Hauterivian. From the foregoing it emerges that the age-limits set for the Shasta Bally batholith on purely palaeontological and stratigraphical grounds are post-Bajocian and pre-Barremian. These criteria favour equally the late Jurassic (Nevadan) and the early Cretaceous (Diablan) orogeny as the time of emplacement of the batholith. Because of the time needed to unroof the batholith, Albers (I964) preferred a late Jurassic age. Reinterpretation of the ammonite evidence now removes the grounds for this preference. The batholith could have been emplaced wholly or partly during, say, the early Valanginian, giving the rest of Valanginian and most (if not all) Hauterivian time for its unroofing before sedimentary burial.

R~re/7~e$ ALBUm, J. P. I964. Geology of the French Gulch Quadrangle, Shasta and Trinity Counties, California. Bull. U.S. geol. Surv. xx4x-J. DRusHenrrz, V. V. & KtmaYAV'rS~.VA, M. P. I96o. [Atlas of Lower Cretaceousfaunas of the Northern Caucasus and the Crimea.] Moscow [in Russian]. 323 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

GERASIMOV, P. A., MIGACHEVA, E. E., NAIDIN, D. P. & STEPLIN, B. P. 1962. [Regional Geology of the U.S.S.R. 5. o7urassic and Cretaceous deposits of the Russian Platform.] Moscow [in Russian]. IMLAY, R. W. x959. Succession and speciafion of the pelecypod AuceUa. Prof. Pap. U.S. geol. Surv. 3X4-G. x96o. Ammonites of early Cretaceous age (Valanginian and Hauterivian) from the Pacific Coast States. Prof. Pap. U.S. geol. Surv. 334-F. JAnn~, H. W., GOTTFRmD, D., WARmQ, L. C. & WORTHING, H. W. i959. Lead-alpha age determinations of accessory minerals of igneous rocks (i953-i957). Bull. U.S. geol. Surv. XO97-B. KINVa~I~, A. R., HALL, W. E. & ALBERS,J. P. 1956. Geology and base metal deposits of the West Shasta copper-zinc district, Shasta County, California. Prof. Pap. U.S. geol. Surv. ~,85. LuPPOV, N. P. & DRUSHCHITZ, V. V. I958. In ORLOV, Yu. A. (ed.). [Principles ofpalaeontology. Mollusca-Cephalopoda II, Ammonoidea, Dibranchiata.] Moscow [in Russian]. MURPHY, M. A. 1956. Lower Cretaceous stratigraphic units of northern California. Bull. Amer. Ass. Petrol. Geol. 4 o, 2o98-119. , t~aXRSON, G. L. & RODDA, P. U. I964. Revision of Cretaceous lithostratigraphic nomenclature, northwest Sacramento Valley, California, Bull. Amer. Ass. Petrol. Geol. 48, 496-5o2. RAT, P. 1963. Conclusions du coUoque de stratigraphie sur le Crdtac6 infdrieur en France, Lyon, septembre, 1963. C.R. Soc. geol. Fr. x963, fast. 8, 4, ~92. SPATH, L. F. 1924. On the ammonites of the Speeton Clay and the subdivisions of the Neocomian. Geol. Mag. 6x, 73-89. WRIGHT, C. W. i957. In ARKEI.L, W. J. et al. In MOORE, R. C. (ed.) Treatise on invertebrate paleontology. L, MoUusca 4, Cephalopoda, Ammonoidea. Kansas (University of Kansas Press). R. Casey

(76) Quartz-dlorlte or gabbro intrusion, California L. Cretaceous/M. Jurassic Quarry near Horsehoe Bar, American River 3 miles north-east of Loomis, Sierra Nevada, Cali- fornia, U.S.A. [c. 39°N, x2o ° 3o'w].

Radiometric age K-Ar (~B = 4"72 × xo-l°year-1; ~e = 0"557 × 1o-l°year -1) Biotite: K = 7.o4%, atm. 4°Ar = 6%, 4°Ar*/4°K = 0.00825, age: I43 [136]m.y. (136 4- 4m.y. in Kulp [196I , p. z I i3] corrected for ~ = o.584).

Stratigraphical age. This intrusion was emplaced during the Nevadan orogeny and is of the same age as the Shasta Bally batholith (see Item 75). It intrudes sediments correlated with the Mariposa Formation, which contains Lower Kimmeridgian ammonites.

Re~rencg$ CURTIS, G. H., EV~RI~EN, J. F. & hpsoN, J. 1958 (see Item 75). KULP, J L. i96I. [M. K. Howarth]

(77) Glauconhie sandstone, Oberpfalz U. Jurassic/U. Jurassic Oberpfalz, Germany [49 ° 20' N, I2 ° ~.].

Radiometric age K-Ar (4# = 4"72 × Io-l°year-1; he ~ 0"584 × Io-X°year-1) Glauconite: K = 5"73%, arm. 4°At = 2o%, 4°Ar*]4°K = o.oo821, age: x36m.y. (i35 4- 4m.y. in Kulp [I96I, p. I 113] ). Age: [ z36] m.y. 324 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Stratigraphical age. Core from Pegnitz xo borehole, at depth of 29"4 In, in Transversarium Zone, Upper Oxfordian. The age is said to be a good one, within 5% of the 'control ages' given by intrusions.

References EVERNDEN,J. F. et al. 196I. KULP, J. L. 196 I. [M. K. Howarth]

(78) Glaueonltlc shale, Oberpfalz U. Jurassic/U. Jurassic Oberpfalz, Germany [49 ° 2o' N, x2 ° ~].

Radiometric age K-Ar (~B- 4"72 X xo-a°year-1; 2e----0"584 × m-l°year -1)

K (%) atm. 'OAr (%) 4°Ar*#°K Age(m.y.) Glauconite (I) 6 I I o'oo791 I3I (2) 5" 96 I x 0"00842 I39 Age: [i35] m.y.

Stratigraphical age. Core from Pegnitz I o borehole, in Ornatentone. of Callovian age. Sample (I) is from a depth of 35"6m; sample (2) from a depth of 33 m. The glauconite occurs as pellets in a clay matrix. The age of the sample (I) is said to be within 1o% of the 'control ages' given by intrusions; that of sample (2) to be within 5%. Both are minimum ages. Kulp (I961 , p. I 113) adopted i39 =k 4m.y.

Refirences EV'eRNDE~, J. F. et al. ~96 x. KULP, J. L. 196i. [M. K. Howarth]

(79) Tuff, California L.-M. Miocene]L.-M. Miocene Hornblende-biotite tuff-breccia, Kinnick Formation (UCMP loc. 2577, below Phillips Ranch mammals and Tehachapi plants), Phillips Ranch, Tehachapi Pass, Tehachapi Mountains, California, U.S.A. (Evernden et al. I964, p. 177 ).

Radiometric age K-At ()lp ------4"72 × Io-l°year-a; he = 0"585 × m-l°year -1) Biotite: no further data given; age: i7.3bm.y. (Curtis, Savage & Evernden I96I , p. 345); I7"3 b + o.6m.y. (Kulp I96i , pp. ixo7, IIX2). x~478: K = 5" I8%, atm. 4°Ar = 34%, age" 17. ibm.y. (Evernden et al. I964, p. I77 ).

Stratigraphical age. Hemingfordian (Curtis, Savage & Evernden x96I, p. 345). Late Heming- fordian (Evernden et aL 1964, p. 177 ). Rg~?'ence$ BtrwA~ DA, J. B. x916. New mammalian faunas from Miocene sediments near Tehachapi Pass in the southern Sierra Nevada. Bull. Dep. Geol. Univ. Calif. xo, 75-85. CURTIS, G. H., SAVAGE, D. E. & EWRNDEN, J. F. I96I (see Item 24). 325 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

EVERNDEN,J. F. et al. x964 (see Item 27). KULP,J. L. x961. WOOD, H. E. I941 (see Item 26). [B. M. Funnell]

Stratigraphical comment. Wood (194 i, pl. I ) suggested a correlation of the Hemingfordian with the Upper Burdigalian [upper Lower Miocene] and Vindobonian [Middle Miocene] of the European succession. Durham, Jahns & Savage (I954, fig. 2) indicated a range from just below the mid- point of the Burdigalian to the mid-point of the Helvetian [lower Middle Miocene]. A late Hemingfordian age would suggest a Vindobonian [Middle Miocene] or Helvetian [lower Middle Miocene] age. The assumption that the determination recorded by Evernden et al. (x964) is the same as that referred to by Curtis, Savage & Evernden (196I) and Kulp (196I) is based on the similarities in the reported stratigraphical and radiometric ages and locations.

References DURHAM, J. W., JAHNS, R. I-I. & SAVAGE,D. E. I954 (see Item 26). WOOD, H. E. i941 (see Item 26). B. M. FunneU

(8o) Tuff, Nebraska L. Miocene/L. Miocene Grey ,citric tuff, approximately 3 ° ft below level of Agate quarry, Stenomylus quarry, and Syndyoceras quarry, Lower Harrison Formation, Cook Ranch, Sioux County, Nebraska, U.S.A. (Evernden et al. I964, p. t 78).

Radiometric age K-At ()lp ---- 4" 72 × IO-l°year-1; ~le = 0"585 x Io-l°year -1) Biotite: no further data given; age: 21-6bm.y. (Curtis, Savage & Evernden 1961, p. 345); 2I'6 b 4- o'7m.y. (Kulp 1961 , pp. IiO7-Iti2). KA48I: K ---- 5" I9%, atm. 4°At = 84%, age: 21 .Dbm.y. (Evernden et al. 1964, p. I78).

Stratigraphical age. Arikareean (Curtis, Savage & Evernden I96I, p. 345). Late Arikareean: mammal assemblages from the lower Harrison Formation are part of the typification of the Arikareean (Evernden et al. 1964, p. 178 ). References CURTIS, G. H., SAVAGE, D. E. & EV~RNDEN, J. F. I96I (see Item 24). EVERNDEN, J. F. et al. I964 (see Item 27). KULP, J. L. I96I. WOOD, H. E. I941 (see Item 26). [B. M. Funnell]

Stratigraphical comment. Wood (1941, pl. t) suggested a correlation of the Arikareean with the Aquitanian and Lower Burdigalian [Lower Miocene] of the European succession. Durham, Jahns & Savage (i 954, fig. 2) indicated a very similar range. A late Arikareean age would suggest the Lower Burdigalian [upper Lower Miocene]. The assumption that the determination recorded by Evernden et al. (1964) is the same as that referred to by Curtis, Savage & Evernden (1961) and Kulp (1961) is based on the similarities in the reported stratigraphical and radiometric ages and locations.

References. As for Item 79. B. M. FunneU 326 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

(8x) Glaueonltlc sandstone, ¢'mllfornla U. Oligocene/U. Oligocene Core from 5688-716ft in Hub Petroleum Cymric No. I, California, U.S.A.

Radiometric age K-Ar (RB ----4"72 × Io-l°year-1; Re = 0"584 × IO-l°year-l) Glauconite KA I7I : K = 5"o9%, atm. 4°Ar ~ 66%, *°Ar*#°K ---- o'oo132, age: 23m.y. (Evern- denetal. I961 , pp. 81, 90); 23 4- Im.y. (Kulp I96I , pp. IIO7, III3). Age: [22" 5] m.y.

Stratigraphical age. Lower Miocene of California (Lower Zemorrian). Base of Lower Santos shale: top of Phacoides sand at 57o5ft (Evernden et al. 196I , p. 9o).

References EVERNDEN, J. F. et al. 1961. KULP, J. L. 1961. [B. M. FunneU]

Stratigraphical comment. Kleinpell (i 938, fig. 14) suggested correlation of the Zemorrian with the Rupelian [Middle Oligocene] of the European succession. Durham, Jahns & Savage (I954, fig. 2) indicated that the Zemorrian corresponded to the Blakeley and Vaqueros marine macro- fossil stages of California. The details given by Evernden et al. (I96I, p. 9 o) suggest that the sample came from a position corresponding to the very base of the Zemorrian in the type-section (Kleinpell 1938, pp. io5-6 ) . If this is so, a position at the base of the Blakeley is indicated. Durham, Jahns & Savage (1954, fig. 2) regard this as equivalent to the Whitneyan, which is equated with the Chattian [Upper Oligocene] of Europe.

References DURHAM,J. W., JAHNS, R. H. & SAVAGE,D. E. I954 (see Item 26). EVERNDEN,J. F. et al. I96I. KLEINPELL, R. M. I938 (see Item 26). B. M. Funnell

(82) Glaueonltlc sandstone~ Austria L. Miocene/L. Miocene Core from 45 "°-47"7m in F.Z.6, Bad Hall, Austria.

Radiometric age K-At (RB = 4"72 × 1G-×°year-a; Re = 0"584 × IO-a°year-1) Glauconite KA445: K -~ 4" I4%, atm. 4°At = 69% , 4°Ar*/4°K = o.oo146 , age: 25m.y. (Evern- den et al. I961 , pp. 81, 99); 25 4- lm.y. (Kulp i961 , pp. 1 lO7, 1113). Age "--- [24" 8] m.y.

Stratigraphical age. Lower Miocene-Burdigalian (Evernden et al. 196 i, p. 99).

References EVERm)EN, J. F. et al. 196 i. KuLv, J. L. 196I. [B. M. Funnell]

(83) Tuff, Oregon U. Oligocene/U. Oligocene Outcrop 60 or 8oft above the bottom of the [? Whitneyan] sequence, John Day basin, Oregon, U.S.A. 327 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometric age K-Ar (~p = 4"72 × lO-l°year-1; ~ = 0"585 × IO-l°year-a) Authigenic sanidine (Curtis, Savage & Evernden I96I, p. 346) [given as biotite by Kulp 196I , pp. 11o7, II13] ; no further data given; age: 25.7bm.y. (Curtis, Savage & Evernden 1961, P- 345); 25"7 b 4- o-8m.y. (Kulp 1961 , pp. IIO7, I113).

Stratigraphical age. Whitneyan (Curtis, Savage & Evernden 1961 , pp. 345-6).

References CURTIS, G. H., SAVAGE,D. E. & EVERNDEN, J. F. I96I (see Item 24). KULP, J. L. I96 i. [B. M. Funnell]

Stratigraphical comment. Wood (1941 , pl. 1) suggested a correlation of the Whitneyan with the uppermost part of the Rupelian [Middle Oligoeene] and the Chattian [Upper Oligocene] of the European succession. Durham, Jahm & Savage (x954, fig. 2) indicated that it was co-extensive with the Chattian.

References DURHAM, J. W., JAHNS, R. H. & SAVAGE,D. E. I954 (see Item 26). WOOD, H. E. 1941 (see Item 26). B. M. Funnell

Radiometric comment. In a later publication, Evernden et al. (I964, p. 18o) have reported 2 I. 6m.y. for an authigenic adularia (KA 646), from claystone about 75ft above the base of the John Day Formation, Central Oregon (see Item 197). It is not certain whether these two Items refer to the same or different determinations. Reference EWRNDEN et al. 1964 (see Item 27). B. M. Funnell

(84) Rhyollti© tuff, Vieja Group L. Oligocene]L. Oligocene Outcrop 4 miles east of Rio Grande River, Presidio County, Texas, U.S.A.

Radiometric age K-Ar (~p = 4"72 × IO-l°year-1; ~ = o'584 × xo-X°year-t) Sanidine (Curtis et al. I96I , p. 35I; Evernden et al. I961, p. 88 [given as biotite by Kulp 196i , pp. ILO7, II13] ) KA483 K----4"73%, arm. 4°Ar = 2I°/o, 4°Ar*]4°K = 0"00195, age: 33.Im.y. (Evernden et al. 196I , pp. 81, 88) ()lp = 4-72 × io-l°year-1; ~ = o.585 × io-X°year-1) 33.xm.y. (Curtis, Savage & Evernden 196I, P. 345); 33 "I 4- I .om.y. (Kulp 1961 , pp. 11o7, 1113) ; 33"om.y. (Evernden et al. 1964, p. 178). Age: [33" I]m.y.

Stratigraphical age. Chadronian (Stovall 1948; Curtis et al. I96I, p. 346); within a few feet of an extensive lower Ollgocene fauna (Curtis et aL 1961, p. 351). R~6~r£nces CURTIS, G. H., SAVAGE,D. E. & EVERN'DEN,J. F. I961 (see Item 24). 328 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items DEFoRI), R. K. 1958. Tertiary formations of Rim Rock country, Presidio County, Trans-Pecos Texas. Texas07. Sci. xo (I), 1-37. Ewm,,o~N, J. F. et al. 196I. et al. I964 (see Item 27). KtmP, J. L. 196 i. STOVALL, J. W. 1948. Chadron vertebrate fossils from below the Rim Rock of Presidio County, Texas. Amer. 07. Sci. 2,16, 78-95 • [I3. M. Funnell]

Stratigraphical comment. Both Wood (1941, pl. I) and Durham, Jahns & Savage (I954, fig. 2) indicate a correlation between the Chadronian and the Lattorfian [Lower Ollgocene] of the European succession.

Referertct$ DURI-IAM, J. W., JAI-mS, R. H. & SAVAO~.,D. E. 1954 (see Item 26). WooD, H. E. I941 (see Item 26). B. M. Funnell

(85) Alkali lmgnmtite, Vakis-Jvary Oligocene/M. Eocene Vakis-Jvary, River Nataneby, Guria, U.S.S.R.

Radiometric age Biotite K-Ar (;t~ ----- 4" 72 × IO-I°year-X; )~ ~---0"557 x IO-l°year-1; *°K/K = 1.22 × Io-4g/gK) No. I (4 runs): K ---- 7"75 -4- o'23%, 4°Ar* = lO9 4- xlmm3/g × lO4, 4°Ar*#°K = [o'oo2o6], age: 37 + 4m.y. (Rubinstein 1961, pp. 365, 366, 367-8); 38 + 4m.y. (Kulp I96I, pp. 11o7, I 113) ; 4 ° + 5 m.y. (Holmes 1959, PP. 2o2-3). (2B=4"72 × Io-X°year-t; Ae=O'584 × IO-t°year-X), age: 394-5m.y. (Kulp I96O, pp. I9, 20). Age: [35" o] m.y.

Stratigraphical age. Upper Eocene; the granite cuts fossiliferous Middle Eocene rocks and is overlain by fossiliferous Lower Oligocene rocks: the intrusion is believed to have taken place in the lower part of the Upper Eocene (Kulp i961 , p. 11 I3). Uppermost Middle Eocene or Upper Eocene; intruding Middle Eocene containing a nummulite farina and pre-Oligocene (Rubinstein I961 , P. 367).

Refefsrlge$ HOLMES, A. 1959. KULP, J. L. I96O. 1961. RUBINSTEm, M. M. 1961. Some critical points of the post-Cryptozoic geological time scale. Ann. X.T. Acad. Sci. 9x, 364-71. [B. M. Funnell]

(86) Glauconitl© sandstone, California U.-M. Eocene/U.-M. Eocene Road cutting, Hernandez Valley, California, U.S.A.

Radiometric age K-Ar (2/~ = 4"72 × Io-X°year-1; 3, = 0.584 × xo-10year-~) 329 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Olauconite KI89: K = 5"42 ~o, atm. ~°Ar = 23%, 4°Ar*/4°K = 0"00255, age: 43m.y. (Evernden et al. 1961, pp. 81, 9I); 43 4- 2m.y. (Kulp 196I , p. 11o7) ; 45 4- 2m.y. (Kulp 196I , p. II13). Age: [43" 2] m.y.

Stratigraphical age. Base of Upper Eocene of California (basal Kreyenhagen).

References EWRNDEN, J. F. et al. 196 I. KULP, J. L. 1961. [B. M. Funnell]

Stratigraphical comment. Bramlette & Sullivan's (I96I, pp. 135-6, 137-8 ) observations on the calcareous nannoplankton suggest that at least part of the basal Kreyenhagen is Middle Eocene.

Reference BgA~LeTTE, M. N. & SULLrVAN, F. R. 196I (see Item 17). B. M. Funnell

(87) Glauconltlc sandstone, Paris basin M. Eocene/M. Eocene 'Fosse, near Survilliers, Paris basin,' France.

Radiometric age K-Ar (2B = 4"72 × lO-x°year-1; ~e = o'584 × ao-X°year-x) Glauconite KA163: K = 6"o2%, arm. *OAr = 38%, 4°Ar*/4°K = o'oo278, age: 47m.y. (Evern- den et al. 1961, pp. 81, 9 o) ; 47 4- 2m.y. (Kulp I96I, pp. 1 lO7, 1113).

Stratigraphical age. Lutetian (Middle Eocene).

References EVERNDEr% J. F. et al. i961. KULP, J. L. i9 6I. [B. M. Funnell]

(88) Glauconltlc sandstone, Austria L. Eocene/L. Eocene Core from 196-9 m in Kressenberg 5, near Ober Teisendorf, Germany.

Radiometric age K-At (2B = 4"72 X xo-X°year-1; 2e = 0"584 × xo-l°year-x) Glauconite K440: K = 4"72%, arm. 4°At = 38%, 4°Ar*/4°K = o'oo3o 3, age: 51 m.y. (Evernden et al. 196 I, pp. 8 I, 98) ; 5 x 4- 2 m.y. (Kulp 1961, pp. x xo7, I 1 ~3).

Stratigraphical age. Alpine (Lower Eocene).

Rgfs'fO'l.C8$ EVERNDEN, J. F. et al. 1961. KULP, J. L. x961. [B. M. Funnell]

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(89) Diorite pluton, Talkeetna Mountains M. Jurassic/L. Jurassic Headwaters of Oshetna River, Talkeetna Mountains, Alaska, U.S.A. [c. 62 ° XO'N, I47 ° 40'W].

Radiometric age K-Ar (hB = 4"72 × IO-x°year-a; he = 0"584 × xo-X°year -1) Biotite: K = 3.63%, atm. 4°At = I9% , ~°Ar*#°K = o'oio4, age: 169m.y.

Stratigraphical age. The diorite pluton intrudes marine volcanic rocks of the Talkeetna Formation, which has ammonites of Pliensbachian age (Imlay 1952, p. 98I). Eroded boulders of the pluton occur in the Naknek Formation of Lower Oxfordian age, but the Talkeetna Formation is overlain unconformably by the Tuxedni Formation, which contains Cranocephalites. The age of the Crano- cephalites beds is problematical; they are considered to be Upper Bajocian-Lower Bathonian by Callomon (1959, p. 5o7) and Bathonian (?Upper)-Lower Callovian by Imlay (1962 , p. 21). The lower age may eventually be shown to be more correct, and the age of the pluton probably approximates fairly closely to the Lower-Middle Jurassic boundary.

References CALLOMON, J. H. 1959. The ammonite zones of the Middle Jurassic beds of East Greenland. Geol. Mag. 96, 5o5-13 . EVERNDEN, J. F. et al. 196 I. I~tLAY, R. 1952. Correlation of the Jurassic formations of North America, exclusive of Canada. Bull. geol. Soc. Amer. 63, 953. -- 1962. Jurassic (Bathonian or early Callovian) ammonites from Alaska and Montana. Prof. Pap. U.S. geol. Surv. 374-c. [M. K. Howarth]

(9o) Intrusions, western Georgia, U.S.S.R. U. Jurassic]M. Jurassic Kelasury [420 57' N, 41° 05' P]; Khevis-Jvary [420 05' N, 420 14' ~].

Radiometric age K-Ar (hB = 4"72 × IO-l°year-1; he = 0"557 × lO-l°year-1; 4°K/K = 1.22 × Io-4g/gK)

K (%) 40At* (mm3]g) *°Ar*#°K Age (m.y.) (I) Biotite from Kelasury granite 6. I75 o'o4Io [0"00974] 167-t-9 [i6o] (2) Biotite from Kelasury granite 5"99 o"°416 [o.oio18] 1744-4 [167] (3) Biotite from Gumysta granite 5-82 o-0404 [0.01018] 1744-8 [167] (4) Hornblende and biotite from x'I8 0"00788 [0-00979] I684-xo [16I] Khevy quartz-diorite (5) Hornblende and biotite from I'5I O'OIII [o'oio77 ] 1854-12 [I76 ] Khevy quartz-diorite (6) Hornblende and biotite from I"5O o'oIox [o.oo987] 17o4- I1 [I62] Khevy quartz-diorite

(I), (3-6) analysed by M. M. Rubinstein, (2) by J. L. Kulp.

Average age: 173 [166 -4- 2]m.y.; excluding (5): I71 [163 4- I]m.y.

Stratigraphical age. The Kelasury granite intrudes Upper Lias and Bajocian sediments and volcanic rocks that include faunas indicating zones up to the Garantiana Zone of the Upper Bajocian. The overlying rocks are of Lower Neocomian age, but some distance away pebbles of the granite 33I Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns occur in ? Kimmeridgian-Tithonian beds. The Gumysta granite intrudes Triassic sediments. The Khevy (Khevis-Jvary) quartz-diorite intrudes the Bajocian volcanic series and is overlain by Lower Neocomian. The three intrusions are of the same age, and this is generally considered to be Bathonian, for this is the date of the most important tectonic phase. Refersnc8 RUBmSlnEm, M. M. I96I (see Item 85). [M. K. Howarth]

(9x) W~rdale grm~te Carboniferous/Silurian Rookhope borehole, Weardale, County Durham, England [54 ° 45'N, 2 ° o I'w].

Radiometric age K-Ar (~/~ ---- 4" 72 × IO-t°year-X; 2e = 0"584 × IO-x°year-1)

Depth (ft) K,O (%) Weight fused (g) 'OAr* (ppm) atm.'°Ar (%) t°Ar*#°K Age (m.y.) I396 iO.Ol 2.o34 0.240 I7" 4 [0-0237 ] 37 ° [366]q-m i314 lO.26 3.291 o'239 24 [o'o23o ] 3564-12

Mean age: 363 4-1Im.y.

Rb-Sr (t½ ----- 4"75 × 1oX°Year)

Depth Rb Normal s~Sr* 87Rb Age (m.y.) (it) (ppm) Sr (ppm) (ppm) (ppm) S~Sr*/S~Rb 4=1"39 4=1"47 1396 763 I9.4 1.I 5 216.1 o'oo532 [382] 36o4-12 I314 757 I9"6 1"15 214"4 o'oo536 [385] 365±12

Mean age: [383]m.y. (4 = 1 "39); 362 d- 12m.y. (4 = 1"47). Weighted mean (both methods) : 362 q- 6 m.y. (Dodson & Moorbath t 961).

Stratigraphical age. The borehole shows no host-rock, and the granite is unconformably overlain by dated Lower Limestone Group limestones, shales, and sandstones of Vis~an age. By analogy with the Cross Fell Inlier, the youngest rocks involved as host-rock would be late Silurian.

References DODSON, M. H. & MOORBATH, S. 196I. Isotopic ages of the Weardale granite. ,Nature, Lond. x9o, 900. DUNHAM, K. C., Boar, M. It. P., JoHNsoN, G. A. L. & HODOE, B. L. I96I. Granite beneath the northern Pennines. ,Nature, Lond. x9o, 899-9oo. [M. R. House]

(9a) Hill of Fare granlte Devonian/Silurian Aberdeenshire, Scotland [57 ° lO'N, 2 ° 3o'w]

Radiometric age Rb-Sr (4 = x "39 X lo-nyear -1) Orthoclase: Rb ----- 397 ppm, Total Sr = 25"2 ppm, s~Sr* -~ 2"3%, s~Sr*/S~Rb -~ [o'oo516], age: 39o [37o] 4- 5om-y. (4 ----- I'39); [35o]m.y. (4 = I"47). [Note: As a weighted average for late Caledonian granites in Britain generally, Long & Lambert (1963) give an age of 39o 4- 5m.y.] 332 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical age. Intruded into metamorphosed Dalradian rocks. No immediately overlying Devonian. Probably Lower Devonian or Upper Silurian. 'Petrologically this granite is like those that supplied pebbles to the conglomerates of the Lower Old Red Sandstone and possibly to the Downtonian' (Holmes I959).

References HOLMEs, A. 1959. LONO, L. E. & LAMBERT, R. ST.J. x963 . Rb-Sr isotope ages from the Moine Series. In The British Caledonides (ed.Johnson, M. R. W. & Stewart, F. H.). London & Edinburgh (Oliver & Boyd), pp. 217-47. SMAI2SS, A. A., MAPP~.R, D., MORGAN, J. W., W~BSamR, R. K. & WOOD, A. J. 1958. Some geo- chemical determinations using radioactive and stable isotopes. Proceedings of the Second U..N. International Conference on Peaceful Uses of Atomic Energy, Geneva, 2, 242-8. [M. R. House]

(93) Creetown grin|re ? M. Devonian/U. Silurian Kirkcudbrightshire, Scotland [54° 5 °' N, 4 ° 20 t W] (erroneously called 'Cairmmore of Fleet' in Mayne, Lambert & York I959)

Radiometric age K-At (2• ---- 4" 72 × lO-t°year-1; 2e = 0"585 × IO-l°year-x) Biotite 2o5o1: K = 6"97%, atm. 4°At = 8%, 4°At* = o'2I 5 ppm, 4°Ar*#°K = [o'o253], age: 39 ° 4- I 2 m.y.

Rb-Sr (2---- I "47 × xo-nY ear-x)

Rb Normal sTSr* STRb Age (m.y.) (ppm) Sr (ppm) (ppm) (ppm) STSr*/S'Rb 2 = i "39 2 = I "47 Biotite 2o5o1 f 532 23"5 o'87 15o'7 [o'oo577] [414] 388-4-19 518 23 "4 o "89 146. 7 [o. oo6o7] [435] 4 lo+2o

Mean Rb-Sr age: 399 -4- I6m.y. (2 = i "47) Age: 395 + iom.y. (Lambert & MAlls 196I).

Stratigraphkal age. Intruded into a fold-belt of Caledonian age involving Wenlockian strata. Upper limit unknown, most probably Lower O.R.S.

References LAMBERT, R. ST.J. & MALLS, A. A. 196I (see Item 6). MAYNE, K. I., LAMBERT, R. ST. J. & YORK, D. The geological time-scale..Nature, Lond. 183, 212- I4. [M. R. House & J. Hacker]

(94) Chattanooga Shale (bentonite) U. Devonlan/U. Devonian Sligo Bridge, Smithville, Tennessee, U.S.A. [35 ° 59'N, 85 ° 49'W].

Radiometric age K-At (decay constants not listed; 4°K/K ----- x .22 × Io'4g/gK)

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Items

K (%) *°Ar* (ppm) 40Ar,#0Artot ,0Ar,#0 K Age (m.y.) Biotite 5.98 O'I57 o'73 [o'o215] ] (" [336] o-i64 o.67 [o'o225] ~ 4134o [35I] o. 155 o- 82 [o. o212] [332] Mean age: 34 ° [-4-6] m.y. [A. G. Smith]

Stratigraphical age. This is a 1-in. biotite bentonite bed in the upper part of the Dowelltown Member of the Chattanooga Shale. The Dowelltown Member is correlated on conodont evidence (Clark & Becker I96 % p. 1667) with the Upper Manticoceras Stufe or Upper Frasnian of Europe. It is older than the other sample determined from the Chattanooga Shale (Item 2), although the radiometric determination does not support this.

Rgfgrgllce$ CLARK, D. L. & BECKER, J. H. 1960. Upper Devonian correlations in western Utah and eastern Nevada. Bull. geol. Soc. Amer. 7 x, 1661-74. FAUL, H. 196o. & THOMAS, H. H. 1959. Argon ages of the great ash bed from the Ordovician of Alabama and of the bentonite marker in the Chattanooga shale from Tennessee. [Abstract.] Bull. geol. Soc. Amer. 7 o, I6oo-x. HOLMES, A. I959. [M. R. House]

(95) Snobs Creek rhyodacite L. Carboniferous/U. Devonian Warburton, Victoria, Australia [37 ° 49' s, 145 ° 44' E].

Radiometric age K-Ar ()lp = 4.72 × IO-l°year-1; 2e = 0"584 X IO-l°year-1) K (%) atm. 4°Ar (%) 4°Ar*#°K Age (m.y.) Biotite KA332 4"94 8 0-0220 344 CA 213 6"78 O'O22I 345 GA 2I 4 6"87 O'O227 353 CA 215 6"86 O'O225 351 GA 2X6 7"O7 O'O226 353 OA 2I 7 6"26 O'O223 348 Average age: 35 ° [4-2]m.y.

Stratigraphical age. The lava-flows form part of the Cerberean cauldron-subsidence, which extends to Taggerty where there are interbedded fish beds. The lavas sampled are above the fish beds, whose faunas indicate a correlation with the top of the Upper Old Red Sandstone of Scotland. They are older than datable Lower Carboniferous fish and plant remains found elsewhere in Victoria (Mansfield). This would suggest a Famennian age. The samples GA 213-I6 are from a single flow; CA 217 from the underlying flow. The localities are spread over a section about 3miles long. No details of the relative position Of KA 332 have been published.

References EVERNDEN,J. F. & RICHARDS,J. R. 1962 (see Item 65). et al. 196I. [P. F. Friend]

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Items

(96) Kineo Volcanic sequence M.-L. Devonian/M.-L. Devonian Moose River synclinorium, Maine, U.S.A. [45 ° 50'N, 69 ° 40'W].

Radiometric age Rb-Sr (~. = I "39 × to-ltyear-1; I "47 X IO-11year -t) Age (m.y.) Sample S~Rb/seSr SsSr/SSSr svSr/SSSr ;~=1 "39 2=I "47 R 3061 9"54 O"I194 O"76I ] Hb 3o6I o'83 o'1195 o'718 R 4565 6-IO O'12OO O.745 375az[z 1o 35oa-4- 1o R 4566 12"44 O'II97 O'777 R 4567 4"91 O.I190 O'739

('Four whole rocks and a hornblende')

Stratigraphical age. The Kineo Volcanic sequence occurs at the Onondaga-Oriskany boundary, i.e., probably later than Siegenian and earlier than Eifelian (House 1962 ). Hence it is Emsian if the correlations with New York are correct.

Rgference$ BOa~NO, M L., PmsoN, W. H., FAmBAXm'~,H. W. & HVRLF.Y, P. M. I962. Rb-Sr age study of the Lower Devonian volcanic sequence at Kineo, Maine. [Abstract.] Program for I962 Annual Meetings, Geological Society of America, p. I2 I. HousE, M. R. 1962. Observations on the ammonoid sequence of the North American Devonian. ,7. Paleont. 36, 247-84. [M. R. House]

(97) Snowy River granite L. Devonian/M. Silurian Victoria, Australia [360 28' s, 1480 17' ~].

Radiometric age K-Ar (;tp = 4"72 × IO-t°year-I; 2e ----- 0"584 × IO-t°year-t) Biotite GA 275: K = 6-I6%, 4°Ar*/i°K = o'o256, age: 394m.y.

Stratigraphical age. Continuous with Koscivsko granite (which, however, may be a composite massif). Intrudes Upper Ordovician and unconformably overlain by rocks high in the Lower Devonian. Art equigranular granite, it contains xenoliths presumably derived from the epi- Ordovician (Benambran) intrusions of the region. The northern extension of the mass at Berridale intrudes the Cowambat Group (Middle and ? Upper Silurian). The age is therefore presumably fixed as Upper Silurian or very early Devonian.

Ref~6"?lce EVERNDEN,J. F. & RICHARDS,J. R. 1962 (see Item 65). [P. F. Friend]

Stratigraphical comment. Talent (I959) cites a rich marine Lower Devonian fauna from overlying beds, and confirms the Middle and Upper Silurian age of the intruded (=Wombat Creek Group) beds.

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Rgfgre?/~ TALENT, J. A. 1959. Notes on Middle Palaeozoic stratigraphy and diastrophism in Eastern Victoria. Min. geol. o7. 6 (3), 57 -8. P. F. Friend

(98) Bear River granite Carboniferous/L. Devonian Nova Scotia, Canada [44 ° 37"N, 65 ° 33'W].

Radiometric age K-Ar (2~ = 4"72 × lO-l°year-t; )~ = 0"585 × lO-l°year-1) Biotite B 3250: K = 6"6o%, ~°Ar*/4°K = o'o24o, age: 37om.y. Rb-Sr (~ = I "39 × Io-ny ear-l) Biotite B 3250: Rb ----54I ppm, Sr = I I "3 ppm, 8~Sr*/Sr = o.o7o , aTSr*/a~Rb = [o-oo516], age: 37om.y. (2 = 1 "39); [35o]m.Y • (2 = 1"47 ). Age: 37om.y. (Fairbairn et al. I96O ).

Stratigraphical age. The granite is intruded into sediments with upper Lower Devonian fossils (I mile east). The Nova Scotia granite complex is, in part, unconformably overlain by Vis~an rocks.

Reference FAIRBAIRN, H. W., HURLEY, P. M., l~soN, W. H. & CORMIER, R. F. 1960 (see Item 7o). [P. F. Friend]

Radiometri¢ comment. See Item 7 o. A. G. Smith

(99) Ni~tatrt granites Carboniferous/L. Devonian Nova Scotia, Canada [44° 53'N, 65 ° 2"W].

Radiometri¢ age K-At (2p = 4"72 X xo-X°year-1; ~ ~ 0"585 × IO-l°year-x)

K (%) 40Ar*/40K Age (m.y.) B 3308 A (Nictaux falls) 5"97 o-o213 333 B 33O8 B (Nictaux falls) 7"34 0.0203 318 B 2O95 (West Nietaux) 7"7 o.o228 370 [355] osc 59-93 (Nictaux-Torbrook) I o- o 0"0234 363

Mean age: 346 [342 4- I o] m.y.

Rb--Sr (2 = I "39 × m-nYe ar-x) Age (m.y.) Rb (ppm) Sr (ppm) S'Sr* (ppm) S~Sr*/SVRb 2=1"39 2=1"47 B 33O8 A (Nictaux falls) 665 11 "5 I. 02 o. o0542 391 [368] B 33o8 B (Nictaux falls) 843 7"5 1.36 o'oo57o 41o [387] B 2O95 (West Nictaux) 431 "~ 6" 9 o" 6o o" oo498 358 [338] 419J 336 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Mean age: 386 [4- x4]m.y. (~ = 1"39); [364 4- 13]m.y. ()l = 1.47 ). Age (both methods) : 365 m.y. (Fairbairn et al. 196o). The two granite samples from Nictaux falls (a 3308A and B) are within Ioooft of baked country- rock and show large discrepancies between results by the different methods. Means, however, give approximately 365m.y. for each sample, and this agrees with the much more similar determinations on the West Nictaux sample (B 2095) and also with the determination on Gsc 59-93.

Stratigraphical age. The granite intrudes and metamorphoses sediments with Lower Devonian fossils; these are regarded as late Early Devonian. The Nova Scotia granite complex is, in part, unconformably overlain by Vis6an rocks.

References FAIRBAIRN, H. W., HURLEY, P. M., PINSON, W. H. & CORMIER, R. F. 196o (see Item 70). LOWDEN, J. A. 1960. Age determinations by the Geological Survey of Canada, Report 1--Isotopic ages. Pap. geol. Surv. Can. 6o-I 7. [P. F. Friend]

Radiometric comment. The biotites B-33oSA and B have discordant K-At and Rb-Sr ages. The lower K-Ar age suggests that they have been subjected to a thermal effect that has been too weak to reset completely the isotopic 'clocks', but strong enough to cause argon loss from some of the micas and lower the K-Ar age. The mean Rb-Sr age of all three determinations calculated from 2 = I "47 × Io-ny ear-1 is 364m.y., which is close to the highest K-Ar age of 363m.y. and is probably the best estimate of the age from the data available. A.G. Smith

Reference KULP, J. L. & ENO~LS, J. i963 (see Item 70).

(xoo) Blue Caay of the Baltic Series L. Cambrian/L. Cambrian (ia, b) Leningrad area; (2) Byelorussia, bore No. 2 at Kupa, 257m; (3) Byelorussia, boreat Rovno, I5o'4m.; U.S.S.R.

Radiometric age K-At (;tp = 4"72 x xo-l°year-1; 3, = 0"557 × Io-l°year-1) K (%) 4°Ar*/4°K Age (m.y.) (I) (a) 6.oi o'o343 533 [51 I] (b) 5"98 o'o347 539 [5 I6 ] (2) 4" 66 o. o349 542 [519] (3) 5" 37 o .o352 545 [523]

Mean age: [517 4- 3] m.y.

Stratigraphical age. Lower Cambrian (Olenellus biozone). The Baltic Series has a fauna including Holmia kjerulfi, Volborthella, and Hyolithes, and the majority of authors draw the lower boundary of the Cambrian along the base of the formation above the upper Laminarites Beds [which is found immediately below tile Baltic Series].

Reference POLEVAYA, N. I. & KAZAKOV, G. A. 1961. [Age classification and correlation of ancient unfossiliferous sediments from Ar4°/K4° ratios in glauconite. Questions on geochronology and geology.] Trudy Laboratoriya Geologii Dokembr~ya Akad. Nauk S.S.S.R. I2, lO3-22 [in Russian]. [J. w. Cowie]

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/tems

Stratigraphical comment. According to Glaessner (I963A , p. 226), the lowest zones of the fossiliferous Lower Cambrian of Scandinavia are represented on the southern margin of the Baltic shield and on the western margin of the Ukrainian shield by the Blue Clay, with a fauna that includes olenellids and plant spores. The Blue Clay and the underlying sandstones of the Super-Laminarites Beds together constitute the widespread Baltic Series. In the northern part of the Russian platform the Baltic Series is underlain by Laminarites Clay and Gdov Sandstones, and these two formations are often combined and called the Valdai Series. The (downward) extension of the Cambrian to include the Valdai Series or the underlying Pachelma Series is rejected by Glaessner (I 963A, p. 227) on the grounds that the argument in favour of this course is exclusively palaeobotanlcal and is unsupported by faunal evidence. As floral changes do not coincide with major stratigraphical divisions of Phanerozoie time, which tend to be expressed in terms of faunal changes, the Valdai Series is not considered to be of Cambrian age (Glaessner, I963B , pp. 4-5)- The Baltic Series may therefore belong to the earliest part of the Lower Cambrian: and the average date of 54om.y. for the Blue Clay (calculated using Russian constants), which extends south-westwards from Leningrad over the Russian platform, may represent the earliest Cambrian date that has sound stratigraphical correlation based on fossil faunas. On general stratigraphical grounds the Super-Laminarites Beds may also be Lower Cambrian, representing the earliest Phanerozoic strata. On the basis of glauconite, Semenenko et al. (I 96o, p. I 15) state that the Super-Laminarites Beds of the Ukraine are 53o to 57om.y. old, but no further details appear to have been published.

References GLAESSNFR, M. F. X963A. The base of the Cambrian. 07. geol. Soc. Aust. xo, 223-4 I. x963 B. The dating of the base of the Cambrian. aT. geol. Soc. India, 4, I-I I. SEMENENKO, N. P., RonloNov, S. P., USENKO, I. S., LICHAK, I. L. & TSAROVSKY, I. D. x960. Stratigraphy of the Pre-Cambrlan of the Ukrainian Shield. Int. geol. Congr. 2x (9), Io8-x5. J. W. Cowie

(xox) Hatchetigbee Formation U. Palaeocene-L. Eocene Gulf Coast, Texas, U.S.A.

Radiometric age K-Ar ()t• = 4"72 × xo-X°year-~; Xe = o'584 × Io-l°year-a) Glauconite r.A438: K =4"46%, atm. 4°Ar=23%, 4°Ar*#°K =o.oo31o; age: 52n.y. (Evernden et al. 196I, pp. 8I, 9o); 52 4- 2m.y. (Kulp 196I , pp. 11o7, III3). Age: [52" 5] n.y.

Stratigraphical age. Upper Wilcox, Bashi Member.

Rgfgrence$ EWRNDEN, J. F. et al. 196 I. KuT.P, J. L. 196 i. [B. M. Funnell]

Stratigraphical comment. The Bashi Member occurs at the base of the top formation (the Hatchetigbee Formation) in the Wilcox Group. According to Murray (i961 , p. 373), the Wilcox group is Sabinian in age and usually considered equivalent to the Ypresian, Cuisian, and possibly parts of the [later] Sparnacian and [early] Lutetian of Europe. A position in the upper Lower Eocene, probably close to the boundary with the Middle Eocene, would be indicated on this basis. On the other hand, Bramlette & Sullivan (196i , p. 137 ) suggest, on the evidence of the calcareous nannoplankton, that the Bashi Formation is either uppermost Palaeocene or basal Eocene. 338 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

References BV~S~LErrE, M. N. & SUTLrVAN, F. R. I961 (see Item 17). MURRAY, G. E. 1961 (see Item 12). B. M. Fun_nell

(to2) Weches Formation M. Eocene]M. Eocene SmithviUe, Texas, U.S.A.

Radiometric age K-Ar (2B = 4"72 × lO-l°year-1; 2e-----o'585 X xo-l°year -1) Glauconite G-326I : K = 3"62%, air corrn = 26%, 4°Ar*]4°K ---= o'oo29, age: 5om.y. (Hurley etal. I96O , pp. 1799, 18o7); 54 4-2m.y. (Kulp I961, pp. 11o7, 1113). Age: [49" o] m.y.

Stratigraphical age. Claibourne Group, Weches Formation, Viesca Member.

References HtmLEY, P. M. et al. 196o (see Item 13). KULP, J. L. 196I. [B. M. Funnell]

Stratigraphical comment. The Claibourne Group has ordinarily been considered equivalent to the Lutetian and Auversian stages of Europe (Murray 1961, p. 379)- The Viesca Member occurs near the base of the middle Claibournian cyclothem (Murray 1961, p. 385), suggesting a mid- Middle Eocene age. On the evidence of the calcareous nanniplankton, Bramlette & Sullivan (I961, p. 137 ) indicate a Lower Lutetian (lower Middle Eocene) age for the lower part of the Weches Formation.

References BRAMr~TaX, M. N. & SUrT.rVAN, F. R. 196I (see Item 17). MORRAY, G. E. 1961 (see Item 12). B. M. Funnell

(IO3) Dacite Eocene/U. Cretaceous Fakhralo, U.S.S.R.

Radiometric age K-At (~tp = 4"72 × IO-x°year-1; 2e = 0"557 X IO-l°year-1; 4°K/K = 1 "22 X Io-4g/gK) Biotite: no analytical details given; age: 57 b 4- 8 m.y. (Rubinstein 196 I, pp. 365, 368) ; 57 b 4- 8 m.y. (Kulp 1961 , pp. i io7, i 113). Age: [54" 5] m.y.

Stratigraphical age. Post-Turonian, but pre-Eocene.

References KULP, J. L. I96I. RUBINSTEIN, M. M. I96I (see Item 85). [B. M. Funnell]

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(xo4) Glauconltle smadstone, ~orn~ Palaeocene]Palaeocene Core from 8o92-IO2 ft General Petroleum Espe Road 75-33 well, California, U.S.A.

Radiometric age K-At (~p = 4"72 × Io-X°yeax-X; ~e = 0"584 × xo-l°Ye ar-x) Glauconite KAX72: K ---- 3"95%, arm. 4°Ar = 39%, 4°At*# °K = o'oo348, age: 58m.y (Evern- den et al. x96I, pp. 8x, 9o) ; 59 4- 3m.y. (Kulp I96I, p. x Io7) ; 6I 4- 2m.y. (Kulp x96x, p. I I I3). Age: [58" 5] m.y. (see radiometric comment).

Stratigraphical age. Top of Palaeoeene at 8063 ft (Evemden et al. i96x , p. 90).

R~6,fgYlg,~s EVERNDEN,J. F. et al. x96 I. KULP, J. L. x96 x. [13. M. Funnell]

Radiometric comment. It has subsequently been shown that this apparently correct glauconlte age is invalid, because detrital material has been incorporated in the outer portions of the glauconite grains. This material was removed by ultrasonic methods and the cores of the grains were dated. Ages that are too young were found: 47.7m.y. (fine-grained glauconite) and 46.4m.y. (residual pellet cores)mas might have been expected on account of the depth of burial (Evernden x964, personal communication). B. M. Funnell

(xo5) Th~-et Sands U. Palaeocene/U. Palaeocene Seacliff at Oldhaven Gap, I/2 to 3/4 mile west of Reculver, Kent, England.

Radiometric age K-Ar (~B = 4"72 × xo-l°year-1; ire ----- 0"584 × IO-x°year-1) Glauconite KA274: K ---- 5"°2%, arm. 4°At ---- 29%, 4°Ar*/4°K = o'oo34x, age: 57m.y. (Evern- den et al. I96I , pp. 8x, 93); 57 4- 2m.y. (Kulp I96I, p. Iio7). Age: [57.5] m.y.

Stratigraphical age. Uppermost Thanet sands (Evernden et al. I96I , p. 93).

Rejtst'~t~g.¢ EVERNDEN, 3" F. et al. 196 t. KULP, J. L. I96X. lB. M. Funnell]

Stratigraphical comment. The Thanetlan Stage is usually regarded as the lower stage of the Upper Palaeocene. Kulp's (x96I , p. I IO7) reference to this sample as coming from the Oldhaven Group [Sparnacian] would seem to be erroneous. B. M. Funnell

(xo6) Glaueonitlc sandstone, f'~.l~fornla Palaeocene/Palaeocene Core [74x7-27 ftT], Standard Oil Co. well no. 62-I3c , California, U.S.A. t Evernden x964 (personal communication). 34 ° Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometric age K-Ar (it# = 4"72 X lO-l°year-1; ~ = o'584 × lO-x°year -t) Biotite KAI76: K = 2"53%, atrn. 4°At = 53%, 4°Ar*# °K = o'oo352, age: 59m.y. (Evernden et al. 1961, pp. 8I, 87); 59 ± 3m.y. (Kulp 1961, pp. 11o7, 1113). Age: [59" 5] m.y.

8tratigraphical age. Palacocene-Martinez (?) (Evernden et al. 196 I, p. 87).

References EVERNDEN, J. F. et al. 1961. KULP, J. L. 196I. lB. M. Furmell]

(XOT) Bishop tuff Plio-Pleistocene/Plio-Pleistocene East side of Sierra Nevada, near Bishop, California, U.S.A.

Radiometric age K-Ar (it/z = 4"72 X IO-l°ycar-1; he = 0"557 × Io-l°year -1)

Age (m.y.) Sanldine (I) (2) KA oIOR 0"68I a o.783 a KA 21ORx O'83 oa O'955 a

(1) based on 4°At* (2) corrected for a 15% loss of radiogenic argon during preheating (see below). (Evemden, Curtis & Kistler 1957, pp. 14-15)

Age: I m.y. (Evernden I959, P- I9) ; i m.y. (Holmes I959, P. 203) ; I m.y. (Cahen i96o, p. 425); I'O -{- o'5m.y. (Kulp 1961 , pp. IIO7, tIi2).

K-Ar (hp ----4. 72 X Io-l°year-1; he----0"585 × IO-i°ycar-I)

Sanidine K (%) atm. 4°At (%) 4°Ar*#°K Age (m.y.) HA 305 (>420/*): 8"5I 57 5"7 × I°-St 0"98 KA 320 (25O--420/*): 8"59 53 5"7 X XO-St 0"98 KA 321 (150--250/*): 8"92 53 5"41 × XO-St O'9I KA 328 (IO5--I50/*) : 8"65 72 5"36 × IO-tt O'92 t Evemden (1964, personal communication).

Mean age: o. 95 m.y.

These results replace those previously published (given above). Inadequate heating invalidated earlier runs, which should be ignored (Evernden et al. 1964, p. 175; Evernden 1964, personal communication).

Stratigraphical age. This tuff lles beneath a widely distributed moraine system, but still overlies glacial till of unknown affinity (Kulp i96i , p. I 1 I2). 34I Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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References CAHEN, L. 196o. EVERNDtCN, J. F. z 959" Dating of Tertiary and Pleistocene rocks by the potassium/argon method. Proc. geol. Soc. Lond. x565, z7-i 9. --CURTIS, G. H. & K:STL~R, R. I957. Potassium-argon dating of Pleistocene volcanies. Quaternaria, 4, z3-I 7. et al. z964 (see Item 27). HOLMES, A. z959. KULP, J. L. i96i. lB. M. Funnell]

(xoS) Rhyolite plug (A) & andeslte block-lava (B) ~/Pliocene Sutter Buttes, 4o miles north of Sacramento, California, U.S.A. (A) De Witt quarry, centre ofsec. 32, "r:6N, R2F, MDM. (a) Near centre ofsec. 6, TI6N, R2~. (Evernden et al. : 964, PP. t 74, t 75) Radiometric age K-Ar (2 k, = 5.03 × io-:0year-l; ),e = 0"552 × IO-l°Year-l)

Biotite Mass (g) K (%) 4°Ar* (IO-:°mol) 4°Ar*#°K Age (m.y.) (A) }C~ 65 :8"734 6-6: 3"53 [9"35 × 10-5] I-69 [I-60] 4- O-IO (B) ~ IOX :6"696 4"O4 I"78 [8"58 × :0 .5 ] I'57 [t'47] 4- 0"24 (Curtis, Lipson & Evernden I956 , p. I36O; Evernden, Curtis & Lipson :957, P. 2122)

(Various constants used) Age: i .5m.y. (Evernden :959, P- :9); 1-6 & x "9m.y. (Davidson x96o, p. 334); i -6 & x-9m.y (Holmes i959, p. 2o3) ; x-6 4- o- 5 & 1 "9 4- o'5m-y. (Cahen I96O, p. 425) 1.6 -+- o.6 ± o'5m.y. (Kulp :959, PP. 69 z, 697); 1.6 4- o'5m.y. (Kulp x96o, pp. :9, 2o); I" 7 4- o.4m.y. (Kulp x96I, p. :IO7); :'5 4- o'5 and z.8 4- o'5m.y. (Kulp :96t, p. 1:I2). ~65: K = 6.6x%, atm. 4°Ar = 79%, age: 1.6 [I .6o]m.y. ~xot : K = 4"o4%, atm. 4°Ar = 92%, age: i "5 [z .47] m.y. (Evernden et aL 1964, P. t 74)

Stratigraphical age. The rhyolite plugs at Sutter Buttes intrude and upturn sedimentary formations of late Cretaceous to early Pliocene age. They were uncovered by erosion before the ensuing period of andesitic intrusions and extrusions. The younger andesite block-lava flow was dated (Curtis, Lipson & Evernden :956, P. I36o; Evernden, Curtis & Lipson I957 pp. 2125-6). Rhyolite plug intrudes Sutter Formation of probable late Blancan age; andesite flow lies on Sutter Formation. Late (?) Blancan. (Evernden et al. :964, PP. 174, 175).

References CAHFN, L. x96o. CTJRTIS, G. H., LIPSON, J. & Ev~m~rDnN, J. F. :956. Potassium-argon dating of Plio-Pleistocene intrusive rocks. Nature, Lond. x78 , i 36o. DAWDSON, C. F. 196o. EVE~'~DF.N, J. F. z959 (see Item :o7). CURTIS, G. H. & L:PSON, J. L. :957- Potassium-argon dating of igneous rocks. Bull. Amer. Ass. Petrol. Geol. 4 x, 212o- 7. et al. :964 (see Item 27). 342 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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HOLMES, A. 1959. KULP, J. L. 1959 (see item 12). 196o. 1961. STmTON, R. A. I93OA. Succession of North American continental P]iocene mammalian faunas. Amer. 97. Sci. (5), 32, 161-2o6. [B. M. Funnell]

(xog) Mount Capanne granodiorite and associated apHte and pegmatite veins L. Pliocene/U. Eocene Elba Island, Italy.

Radiometric age Rb-Sr (4 = I "39 × lo-ny ear-l, and it = I "47 × lo-ny ear-l) Rb (ppm) Sr c°m (ppm) svSr* (ppm) (A) Pollucite I846 4- 62 5"Ol 4- o-o8 o.o 4I q- o-oo 9 (B) Pollucite I434 4- 44 1.66 4- o-o3 o.o376 4- o-oo35 (c) Pink lepidolite II 164oo 4- 3oo lO'45 4- o'25 o'483 4- o'o46 (D) Pink lepidolite III 1738o 4- 3 °o 9" 14 4- o'23 o'463 4- o'o4 ° (~.) White lepidolite II 31o7 4- 31 3"49 4- o'o5 o'o9o -4- o'oo7 (F) White lepidolite 1II 10920 4- 620 3"4o 4- 0.08 0"279 4- o.o16 (o) Biotite from granodiorite 11 io 4- 18 3" 19 4- 0.08 o .o496 4- o.o173

Age (m.y.) aTSr*/STSrt°t STSr*/S7Rb(× lO 5) it ~--- I "39 it = I "47 o" IO [7"84] 5"7 5"4 4- I "3 o'24 [9"26] 6.6 6"2 4- o'7 o'39 [lO'4] 7"5 7"I 4- o.8 o'42 [9"41] 6"7 6. 3 4- o.6 o'27 [lO'2] 7'5[7"3] 7"I [6"9] 4- o.6 0"54 [9"02] 6"5 6" I 4- 0"5 o.18 [15"8 ] lO'4111"4] 9"8 [lO"7] 4- 3"6 Mean ages: [7" 4] [7" o -4- o. 5] m.y. (Ferrara et al. 196I , p. 148; Eberhardt & Ferrara I962, p. 666)

K-Ar (itB = 4"72 × lO-l°year-1; ite ---- 0"585 × IO-l°year-1; 4°K/K = o'oII9 at.%) (no further data given) (D) 6"4b 4- o.6m.y. (o) 7.6 b 4- o.4m.y. (Eberhaxdt & Ferrara I962, p. 666)

Stratigraphical age. Pre-Tabianian (lowest Pliocene of Mayer-Eymar) (Tongiorgi & Tongiorgi 1964, pp. 365-7). Post-Upper Eocene (Ferrara et al. 1961, p. 146; Eberhardt & Ferrara 1962 , pp. 665-6).

R~re/~e$ ESEI~rIAm~T, P. & FERRARA, G. 1962. Confirmation of the absolute age of the granodiorlte outcrop in Elba Island with potassium-argon measurements. Nature, Lond. 196, 665-6. FERRARA, G., HIRT, B., MARII~LLI, G. & TONOIOROI, E. 1961. Primi risultati sulla determina- zione con il metodo del rubidio-stronzio dell'et~t di aleuni minerali dell'Isola d'Elba. Boll. Soc. geol. ital, 80 (2), I45-5o. 343 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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TONGIORGI, E. & TONGIOROI, M. 1964 . Age of the Miocene--Pllocene limit in Italy..Nature, Lond. 2ox, 365-7 . [B. M. Funnen]

Stratigraphical comment. Tongiorgi & Tongiorgi (x964) give a detailed discussion of the stratigraphy of the deposits containing pebbles presumed to be derived from the erosion of the Elba intrusions. They find granite-porphyry and porphyritic aplite pebbles first appearing in Tabia- nian gravels, followed by granodiorite gravels in the succeeding Piacenzian. If their interpretation is correct, the concordant age of approximately 7m.y. given by the Elba intrusions presumably relates to the very latest Miocene or the Mio-Pliocene boundary. B. M. Funnell

(IIO) Glaucol~tlc sandstone, Germany U. Miocene]U. Miocene Core from well near Kadenberge (25 km south-west of Stade), Germany.

Radiometric age K-At (2p = 4"72 × IO-l°year-1; 2e = 0"584 × Io-l°year -x) Glauconite KA322: K-~5.28%, atm. 4°Ar ---- 57%, 4°Ar*#°K----o'ooo562, age: 9.5m.y. (Evernden et al. I96I , pp. 8I, 97) Age: [9" 60] m.y.

Stratigraphical age. Upper Miocene. Reference EVERNDEN, J. F. et al. x 96 I. [B. M. Funnell]

Stratigraphical comment. Evernden et al. (I96I , p. 97) regarded this determination as too young for the Miocene, because it did not agree with results from the western U.S.A.; but see Item Io 9 regarding the likely date for the Mio-Pliocene boundary in Europe. B. M. Funnell

(x x x) Glauconitic sandstone, Germany U. Eocene/U. Eocene Core from well near Nevenhaus (a few kilometres west of Hordhorn), Germany.

Radiometric age K-At (~.# = 4"72 × IO-l°year-X; 2e = 0"584 × Io-X°year-1) Glauconite KA324: K = 6-I6%, atm. 4°At ---- 64%, 4°Ar*#°K = o-ooi85, age: 3xm.y. (Evern- den et al. I96I, pp. 87, 97) Age: [3I .4] m.y.

Stratigraphical age. Upper Eocene. R~Teg/ce EV~RNDEN, J F. et al. I96X. [B. M. Funnell]

Stratigraphical comment. Evernden et al. (I96I, p. 97) regarded this determination as too young, if 'Oligocene of Europe is time equivalent of Oligocene of western U.S.A.' B. M. Funnell

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Items

(xx2) Glauconltic sandstone, California Palaeocene/Palaeocene Core from 8o92-1o2 ft in Standard Oil Co. no. 62-I3C , California, U.S.A.

Radiometric age K-At (2p = 4"72 × Io-i°year-1; 2e = 0"584 × xo-l°year -1) Glauconite KAI78: K = 4"94%, atmos. 4°At = 7o%, a°Ar*/4°K = 0"00273, age: 46m.y., regarded as invalidated by deep burial and heating (Evernden et aL 1961, pp. 81, 91) Age: [46" 2] m.y.

Stratigra#hical age. Palaeocene of California (Martinez) (Evernden et al. I96I, p. 91).

Reference EVERI~rO~I% J. F. et aL 1961. lB. M. Funnell]

(II3) Basal Lodo Formation U. Palaeocene/U. Palaeocene California, U.S.A.

Radiometric age K-Ar (2p = 4"72 × IO-l°year-1; ~e ~ 0"585 × Io-l°yea r-l) Glauconite 0-3694: K = 5.32%, air corm = 55%, 4°At*/4°K = 0"00346 age: 6om.y. (Hurley et al. I96O , pp. 18oo, I8O7) Age = [58. 5] m.y.

Stratigraphical age. Basal Lodo Formation (Palaeocene).

Reference HURLEY, P. M. et al. 196o (see Item I3). []3. M. Funnell]

Stratigraphical comment. On the evidence of the calcareous nalmoplankton, Bramlette & Sullivan (1961 , pp. 134 , I36 ) considered the basal Lodo as equivalent to the Thanetian of England.

Reference BRAMLETTE, M. N. & SULLIVAN, F. R. 196I (see Item 17). B. M. Funnell

(xx4) Moody Branch Formation U. Eocene/U. Eocene Gulf Coast, U.S.A.

Radiometric age K-At (2~ = 4"72 × Io-l°year-1; 2e = 0"584 × xo-X°year-1) Glauconite KAI66: K -- 3"85%, atm. 4°At = 39%, 4°At*/4°K = o'oo233, age: 39m.y. (Evern- den et al. 1961, pp. 81, 9 o) Age: [39"4] m.y.

Stratigraphical age. Base of Upper Eocene of Gulf Coast (Moody Branch Formation at base of Jackson Stage) (Evernden et aL 196I, p. 9o).

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Items

Reference EVERNDEN, J. F. et al. I96I. [13. M. Funnell]

Stratigraphical comment. According to Murray ( 196 i, pp. 389, 39 o), the Moody Branch Formation forms the base of the Jackson Stage, which is ordinarily considered equivalent to the Bartonian and Ludian stages of Europe.

Reference MURRAY, G. E. ,96I (see Item 12). B. M. FunneU

(x 15) Domenglne Formation M. Eocene/M. Eocene Core from 4579--99 ft in Magnet Oil Fearron no. 2, California, U.S.A.

Radiometric age K-Ar (2p = 4"72 × xo-l°year-1; Re = o'584 x xo-a°year-1) Glauconite KAX53: K = 5"82%, atm. 4°Ar = I8%, 4°Ar*/4°K = o'oo249, age: 42m.y. (Evern- den et al. 196I, pp. 8I, 89) Age: [41.8] m.y.

Stratigraphical age. Very top of Middle Eocene of California (Domengine Formation) (Evernden et al. I96I, p. 89).

Reference EVERNDEN, J. F. et al. 196 I. [B. M. Funnell]

Stratigraphical comment. Bramlette & Sullivan (I96i , p. 137) indicate that on the evidence of the calcareous nannoplankton the Domengine Formation is equivalent to the Lutetian.

Refere?lc6

BRAML~TTZ, M. N. & SULLIVAN, F. R. 1961 (see Item 17). B. M. Funnell

(xi6) Lower part of Ashinsk Series late Pre-Cambrian]late Pre-Cambrian Southern Urals, U.S.S.R.

Radiometric age K-Ar (2B = 4'72 × IO-l°year-X; Le = o'557 x Io-l°year-X) Glauconite: K = 5"79%; 4°Ar*# °K -- o'o372, age: 573 [549]m.Y.

Stratigraphical age. No big break occurs between the Ashinsk Series and the Karatau Series.

Reference POLEVAYA, N. I. & KAZAKOV,G. A. ,961 (see Item IOO). [J. W. Cowie] 346 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. According to Glaessner (I963B, table I, pp. 3-6), the Karatau Series and the Ashinsk Series that overlies it are equivalent to the Riphean. The topmost strata of the Riphean include the Laminarites Beds, which are probably Pre-Cambrian (see Item x 17). The Ashinsk Series was included in the original definition of the Riphean, and the oldest fossils found above it are of Upper Ordovician age. Evidently the majority of Russian geologists consider the Ashinsk Series to be an equivalent of the Valdai Series (Glaessner I963B, p. 6; see also Item Ioo). According to Semenenko et al. I96O, the radiometric age of the effusive beds in the upper part of the Riphean section is 57o to 63om.y. They underlie the Cambrian, the lowest rocks of which are 53o to 57om.y. old.

Referertce$ GLAESSNER,~/[. F. I963 B (see Item IOO). S~M~ZENKO, N. P. et al. (see Item xoo). j. w. Cowie

(xI7) Lamtnarites Beds and probable equivalents late Pre-Cambrian] late Pre-Cambrian (A) Left bank of Dniester; (B) Rjasan-Pachelma depression, Lipyagi village; (c) Rjasan-Pachelma depression, Serdobsk, U.S.S.R.

Radiometric age K-At (2p = 4'72 × IO-l°year-1; ;re----0"557 × IO-l°year -1)

K (%) 4°Ar*/4°K Age (m.y.) Glauconite (A) 3"66 o.o385 590 [565] (B) 5"84 0"0392 598 [574] (C) 5"33 O'O398 606 [58~]

Mean age: 595 [572] m.y.

Stratigraphical age. (A) Yaryshev horizon of Ladov Series--same age as the Laminarites beds, Valdai Series; (B) and (c) Laminarites Beds, Valdai Series. The majority of authors draw the lower boundary of the Cambrian along the base of the formation above the upper Laminarites Beds.

Reference POLEVAYA, N. I. & KAZAKOV,G. A. I96I (see Item ioo). [J. w. CoMe]

Stratigraphical comment. See Item ioo for the argument that the Valdai Series is Pre-Cambrian. J. W. Cowie

(ix8) Ulksk Beds of Karatau Series late Pre-Cambrian/late Pre-Cambrian Western slopes of southern Urals, U.S.S.R. (A) Basin of river Bassa; (B) Basin of river Zilim.

Radiometric age K-At (~8 ---- 4"72 x xo-X°year-l; ile ---- 0"557 × IO-lOyear -1)

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K (%) 4°Ar*#°K Age (m.y.) Glauconite (A) 6" I4 o-o4o 5 616 [59 o] (n) 5.oo o.o4o 7 618 [593] Mean age: 615 [59I]m.y.

Stratigraphical age. (A) and (a) Glauconific sandstones of the Uksk Beds from the western slopes of the Urals are probably of the same age as the Laminarites clays [-- Laminarites Beds, Valdai Series]. The majority of authors draw the lower boundary of the Cambrian along the base of the formation above the upper Laminarites Beds.

Reference POLEVAYA,N. I. & KAZAKOV~G. A. I96I (see Item IOO). [J. w. Cowie2

Stratigraphical comment. See Item 1oo for the argument that the Valdai Series is Pre-Cambrian. J. W. Cowie

(II9) Granite de Ch~teau-Chinon U. Carboniferous/L. Carboniferous Quarry outside Dommartin (Huis Jacques) on the road to Bliames (D. 29I), Ni~vre, France.

Radiometric age Rb-Sr (it ---= 1.47 × Io-nyear-a; SVRb/Rb = 27.85 at. %, sTSr/Sr ----- 7"o2 atomic %) Sr prim. Age (m.y.) Rb (ppm) (ppm) S7Sr*(ppm) s~Sr*/Sr sTSr*/STRb it----- 1.39 it---- 1-47 Biotite [o'oo413] [296] [28o] 282-296 I23 28 o- 158 [o "oo4542 [826] [8o82 ~93-3o8 i22 28 o. 148 7% [o" 00428 ] [807] [290 ] 292-307 2 II6 29 o-152 [o'oo463] [332] [314] 300-315 Mean age: [315]m.y. (2 = I "39); 3 °0 ~ rom.y. (it ----- 1 "47)-

Stratigraphical age. Said to be Westphalian-Stephanian and the same age as the Luzy granite (given as 3o3 ~ I o m.y. but with no radiometrie data) ; it contains enclaves of the Visdan 'Gien- sur-Cure granite'. Reference DFsl, ols, J., SANSEL~m, H. & VIAImTTn, Y. 1963. Granitisation vis6enne au Nord-Est du Massif Central. G.R. Acad. Sci., Paris, 256, 2193-5. [E. 14. Francis]

Stratigraphical comment. Michel-L6vy and Lemoine (194o) show Stephanian rocks resting on and younger than the Luzy granite, but no Westphalian rocks have been mapped in the vicinity of this intrusion or of the ChAteau-Chinon granite farther north (Michel-L6vy 1937).

References MICHEL-L~vY, A. I937. Carte gdologique ddtaillde, No. 124. Feuille de ChAteau-Chinon (2nd edn). & LEWOINE, P. 1940. Carte gdologique d~taill~e, No. I86. Feuille d'Autun. E. H. Francis 348 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(x2o) Saknaarlan limestone L. Permian/L. Permian Indiga River, northern Timan, U.S.S.R.

Radiometric age K-Ar (;t/~ = 4"72 × IO-x°year-X; ire = o'557 × IO-l°year-1) Glauconite: K = 4.62%, 4°Ar*/4°K = o.oi64, age: 274 [262]m.y.

Stratigraphical age. Sakmarian (= Wolfcampian) stage of Lower Permian.

Reference POLEVAYA, N. I., MtrRINA, G. A. & KAZAKOV, G. A. I96I (see Item 2o). [D. B. Smith]

Stratigraphical comment. The authors' site and stratigraphical data are given in full above, and no further details are at present available. The term Sakmarian is still used in different senses by different Soviet authors, and it is not possible to say in which sense it is used here. However, its use indicates that the beds concerned are post-Carboniferous, pre-mid-Artinskian, and as such this determination gives a valuable minimum age-limit for the Carboniferous-Permian boundary. D. B. Smith

(x2x) Granlte, Queensland L. Jurassic/L. Permian Carpenter's Gully, Severn River, Queensland, Australia [2I miles south-west of Startthorpe, IO miles west of Wyberba; I5 I° 42'E, 28 ° 5I'S].

Radiometric age Molybdenite. Re-Os (t t = 4"3 4-o- 5 × IO-x°year-x) Re = 94"4 ppm, asTOs = o.2I 7 ppm, age: ~25" 4- 4om.y.

Stratigraphical age. Not given by authors. See stratigraphical comment.

Re~rence HIRST, B., H~mt, W. & HOrF~n~IST~R, W. I963. Age determinations by the rhenium-osmium method. In Radioactive dating. Vienna (International Atomic Energy Agency), pp. 35-43- [D. B. Smith]

Stratigraphical comment. Molybdertite in the Carpenter's Gully area is closely associated with acid aplite veins in the marginal zone of a small stock of fine-grained granite which cuts metamorphosed beds of the Lower Bowen (Sakmarian-Artinskian) Series. This intrusion, one of the 'Sandy' granites of the New England granite complex, lies a short distance west of the main Stanthorpe granite, but is of a type that elsewhere cuts the latter. According to Saint-Smith (I9~4) , the Stanthorpe type of granite is the middle member of an intrusive phase, being followed by the intrusion of the 'Sandy'-type granites and then by the aplites and pegmatites with which the mineralization is associated. The molybdenite thus represents the last phase of the post-Hunter- Bowen intrusive episode, which is known to be post-early Tatarian and is most probably late Tatarian or early Triassic. The calculated age agrees well with that of the Stanthorpe granite (see Item 69 for further discussion).

DAVID, T. W. E. 1950 (see Item 65). HILL, D. & DENMEAD,A. K. (eds) 1960. The geology of Queensland. 07. geol. Soc. Aust. 7.

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SAINT-SMITH, E. C. I9I 4. Geology and mineral resources of the Stanthorpe, Ballandean and Wallangara districts, southern Queensland. Rep. geol. Surv. Qd, 243. D.B. Smith

(122) Castro Dalre granite Permian/U. Carboniferous South-east of Oporto, north Portugal. Exact site not given.

Radiometric age Rb-Sr (2 = 1"47 x Io-nyear-1; 87Rb/Rb normal = 27.85 at %, 87Sr/Sr normal = 7"o2 at. %) Age (m.y.) Rb t°t STSr 87Sr (%) STSr*/S7Rb 2 = I"39 2 = I'47 Biotite (i) fi.573 x .782 85 [0"00400] [287] [272] \i 544 I" 836 85 [o" oo42o ] [3o I ] [285] (2) f I'584 I "768 84 [0"o0394] [283] [267] \i 553 I" 824 84 [o" 00415] [298] [282] f1"538 I'9O7 83 [0"oo438] [314] [297] (3) \i • 63I I'924 83 [o'oo 4I 7] [299] [283] Mean age: [297]m.y. (;t = 1.39), 282 + 7 [± 4]m-Y • (2 = 1-47 )

Stratigraphical age. The granite intrudes and metamorphoses Stephanian; and fragments of the granite are found in the Autunian sediments of the Buqaco basin.

Reference BONHOMM~., M., M_~ND~S, F. & V~LEW'rE, Y. I96I. Ages absolus par la m6thode au strontium des granites de Sintra et de Castro Daire au Portugal. C.R. Acad. Sci., Paris, o52, 3305-6. [E. H. Francis]

Stratigraphical comment. The Stephanian beds in northern Portugal are regarded as Middle Steph- anian (Stephanian B) in age, after floras described by Teixeira (1944, etc.) and others. These beds constitute a post-orogenic succession formed after the Asturian phase of folding. No evidence of Lower Stephanian (Stephanian A) deposits has been found in the area; the youngest earlier Carboniferous strata are of high Westphalian D age. Teixeira regards the fossil flora as rather homogeneous throughout the Stephanian exposures, but no indication of sampling throughout an established stratigraphic succession has been given. The recorded flora mainly indicates high Stephanian B age, although early Stephanian C cannot be excluded. The Autunian beds of Bu~aco also constitute a post- or late-orogenic succession of strata that are mainly conglomeratic in nature. Floral elements recorded by Teixeira (I 944) indicate a lower Autunian age. They consist mainly of Stephanian species, which are accompanied by Callipteris conferta Sternberg. The basal Autunian aspect of the flora is underlined by Doubinger (I956), who referred it to her 'Stephanian D', which is a transition stage between Stephanian and Autunian sensu stricto. The Castro Daire granite as defined and mapped by Schermerhorn (I956) does not itself cut Stephanian sediments, though another granite of the same group does. It is not clear from Scher- merhorn or from Teixeira (I959) whether or not the granite fragments in the Autunian conglomerate originated from the Castro Daire group of intrusions.

References DOUBINOER, J. I956. Contribution ~t l'&ude des flores autuno-st6phanlennes. Mdm. Soc. glol. Fr. (N.S.), 35 (I), 74- 350 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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SCHERMERHORN, L. J. G. I956. Igneous, metamorphic and ore geology of the Castro Daire- SAo Pedro do Sul-S~tao region (northern Portugal). Comun. Serv. geol. Portug. 37. TEIXEIRA, C. 1944. O antracolitico continental portuguSs. Bol. Soc. geol. Portug. 5 (i-z), I-I4O. 1959. L'6volution du territoire portugais pendant les temps ant6-m6sozoiques. Bol. Soc. geol. Portug. i3, 229-55. R. H. Wagner

(z23) Winona Sand M. Eocene/M. Eocene Gulf Coast, U.S.A.

Radiometric age K-At (2~ = 4"72 × IO-l°year-1; ~te = 0"584 × Io-X°year-X) Glauconite KAI65: K=6.22°/o, atm. 4°Ar= 27°/o, 4°Ar*/4°K =0.00230 , age: 39m.y. Evernden et al. 196I , pp. 81, 9 o)

Stratigraphical age. Lower Mid-Eocene (Winona Sand of Lower Claiborne) (Evernden et al. I961, p. 9o). Reference EVERND~N, J. F. et al. 196 i. []3. M. Funnell]

Stratigraphical comment. The Claiborne group has ordinarily been considered equivalent to the Lutetian and Auversian stages of Europe (Murray I961, p. 379). The Winona Sand occurs at the base of the middle Claibornian cyclothem (Murray, 196I , p. 385), suggesting a mid-Middle Eocene age. The radiometric age is young compared with that in Item lO2 (q.v.).

Reference MURRAY, G. E. I96I (see Item I2). B. M. Funnell

(124) Stave Creek Formation M. Eocene/M. Eocene Gulf Coast, U.S.A.

Radiometric age K-Ar (2~ = 4"72 × lO-l°year-1; 2e = 0"584 × lO-l°year-1) Glauconite KAI73: K ----- 5"43%, atm. 4°Ar = 23% , 4°Ar*/4°K = o.oo25 o, age: 42m.y. (Evern- den et al. 1961 , pp. 8I, 91) Age ---- [42" 4] m.y.

Stratigraphical age. Base of Middle Eocene of Gulf Coast (Stave Creek Formation) (Evernden et al. 196I, p. 9I).

Re, fence EVERNDEN, J. F. et al. 19 61. [B. M. Funnell]

(125) ]K~tan sediments U. Eocene/U. Eocene South Island, New Zealand. 351 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometric age K-At (2B = 5.03 X lO-x°year-X; 2e = 0"552 X xo-X°year-x) Atm. K (%) '°Ar (%) 'lOAr*/4°K Age (m.y.) Glauconite 44 6" I x 69 o.oo2o7 37"o [35" o] 4- 2"6 45 5"87 37 o.oo226 4o"5 [38. 2] 4- 2.8 (I_.ipson I956, pp. I5O--1; I958, pp. I44, I45-7)

Age: 34-5m.y. (Kazakov & Polevaya 1958 , p. 384); 37-49m.y. (Davidson 196o, p. 334, no. x 1 ). (2p = 4"73 × lO-l°year-x; ~ = 0"584 × lO-x°Year-x) Age: 37 4- 3m-y • (Kulp i959, pp. 69I, 694)

Stratigraphical age. Kaiatan (Lipson I956, 1958)

References DAVIDSON, C. F. I96O. KAZAKOV, G. A. & POn~VAYA, N. I. I958 (see Item 12). KunP, J. L. I959 (see Item 12). LiPsoN, J. 1956 (see Item 12). 1958 (see Item 1~). [B. M. Funnell]

Stratigraphical comment. Hornibrook (in Fleming 1959, P. 153) suggested an Upper Eocene age for the Kaiatan; similarly, Eames et al. (I962, fig. 4) indicated a lower Upper Eocene age. The planktonic Foraminifera listed from the Kaiatan by Hornibrook (ibid., table 6) are consistent with this interpretation but do not seem to preclude a possible upper Middle Eocene age.

References EA~mS, F. E., Ba~R, F. T., Bnow, W. I-I. & Cr.aRgE, W.J. I962. Fundamentals off'mid-Tertiary stratigraphical correlation. London (Cambridge University Press). Fr_~Mma, C. A. 1959 (see Item I7). B. M. Funnell

(126) Ihmtroonlan-Wha~garoan st~llrnents Oligocene/O li gocene North Island, New Zealand.

Radiometric age K-At (2p = 5"°3 × I°-X°year-X; 2e = 0"552 × xo-X°year-x) Glaueonite 39: K = 5"93%, arm. 4°At = 62~'o, 4°Ar*/4°K = o.oo122, age: 22.o 4- I'5m.y. (Lipson 1956, p. I5o; I958, pp. I44, 146-7) Age: 22m.y. (Kazakov & Polevaya I958, p. 384); 22m.y. (Davidson I96O, p. 334, no. 8) (2p = 4"7~ × IO-x°year-X; 2e -~ o'584 × IO-x°year -1) Age: 2i 4- 2m.y. (Kulp 1959, pp. 69I, 694 ) Age: [2o- 8] m.y.

Stratigraphical age. Duntroorfian-Whaingaroan (Lipson 1956, 1958).

References. As for Item 125. [.]3. 1VL Funnell] 352 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. Hornibrook (in Fleming 1959, pp. 97, 476) suggested that the Whain- garoan and Duntroonian stages are Lower Oligocene. The planktonic Foraminifera (Hornibrook ibid., table 6) are probably consistent with a Lower or Middle Oligocene age (el. Eames et al. I962, p. 22, fig. 4)-

References. As for Item 125. B. M. Funnell

(t27) Waitakian sediments L. Miocene/L. Miocene North Island, New Zealand.

Radiometric age K-Ar (2p = 5"03 × Io-l°year-t; 2e = 0"552 × lO-t°year-x) Glauconite 50: K = 5.I2%, atm. ~°Ar = 55%, 4°Ar*# °K = o'°°114, age: 20. 4 4- 1.2m.y. (Lipson i956 , p. 15o; i958 , pp. i46--7) ; 14-22m.y. (Kazakov & Polevaya I958, p. 384); 2om.y. (Davidson I96O , p. 334, no. 7)- (2# = 4"72 × Io-l°year-X; 2e = 0"584 × IO-l°year -x) Age: 19 4- 2 m.y. (Kulp 1959, PP- 69 i, 694 ) Age: [I9.4] m.y.

Stratigraphical age. Waitakian (Lipson 1956, 1958).

References. As for Item 125. [B. M. Funnell]

Stratigraphical comment. Hornibrook (in Fleming 1959, p. 457) suggested a possible Rupelian [Middle Oligocene] age for the Waitakian, but the joint occurrence of the planktonic Foramini- fera Catapsydrax dissimilis and Globoquadrina dehiscens in the Waitakian (Hornibrook, ibid., table 6) indicates at least a middle Aquitainian [Lower Miocene] age (el. Eames et al. 1962 , p. 22, fig. 4).

References. As for Item 125 . B. M. Funnell

(128) Hutch~tson;~n sediments L. Miocene/L. Miocene South Island, New Zealand.

Radiometric age K-Ar (2p = 5"o3 × Io-X°year-l; 2e-----o'552 × IO-l°year-1) Glauconite 52: K = 5"56%, atm. 4°Ar = 48%, 4°Ar*#°K = o.ooo9o 5, age: I6" 3 4- I .om.y. (Lipson 1956, p. 15o; 1958 pp. I44, I46-7); I4m.y. (Kazakov & Polevaya 1958, p. 384); I6m.y. (Davidson I96o , p. 334, no. 6). (2B = 4"72 × Io-l°year-X; 2e = 0"584 × xo-a°year-1) Age: 16 ± 2m.y. (Kulp 1959, pp. 69 I, 694) Age: [I5"4]m.y.

Stratigraphical age. Hutchinsonian (Lipson I956, I958).

References. As for Item I25. [B. M. Furmell]

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Items

Stratigraphical comment. Hornibrook (in Fleming 1959, p. I42 ) suggests an Upper Oligocene or Lower Miocene age for the Hutchinsonian. The association of the planktonic Foraminifera Catapsydrax dissimilis and Globoquadrina dehiscens in the Hutchinsonian (Hornibrook, ibid., table 6) indicates a middle to upper Aquitainian [Lower Miocene] age (el. Eames et al. I962, p. 22, fig. 4).

References. As for Item 125. B. M. Funnell

(129) Waiauan sediments M. Miocene/M. Miocene North Island, New Zealand.

Radiometric age K-Ar (2 B = 5.o3 × ×o-×°year-X; 2e = o'552 × IO-a°year-x) Glauconite 56: K = 4"8o%, atm. 4OAr = 64%, 4°Ar*/4°K = o.oo117, age: ~,i. i 4- 1 "5 m.y. (Lipson 1956 , pp. I5O-I ; 1958, pp. I44, I46-8); 18 m.y. (Kazakov & Polevaya I958, p. 384); 21 m.y. (Davidson 196o , p. 334, no. 5 [pars]). (2/~ = 4-72 × xo-l°year-X; 2e = o'584 × xo-X°year-1) Age: 2o -4- 2 m.y. (Kulp I959, pp. 69I, 694 ) Age: [I9.9] m.y.

Stratigraphical age. Waiauan (Miocene) (Lipson 1956, I958 ).

References. As for Item 125 . [B. M. Funnell]

Stratigraphical comment Hornibrook (in Fleming 1959, p. 429) states that 'there is strong evidence for correlating the Waiauan with the Indonesian upper "f" stage currently regarded as approximately Tortonian' [upper Middle Miocene]. The planktonic Foraminifera listed by Hornibrook [ibid., table 6] are consistent with a Vindobonian [Middle Miocene] age (cf. Eames et al. 1962, fig- 4).

References. As for Item 125. B. M. Funnell

(I30) Sylvinite, Kalibergwerk, Bugglngen, etc. L. Oligocene/L. Oligocene Upper Rhine, Germany.

Radiometric age K-Ar (for experimental details, see Smits & Gentner i95o , Gentner, Pr~ig & Smits I953, Gentner, Goebel & Pr~ig I954) Age: 2oam.y. (Smits & Genmer i95o , p 22); 2I a 4- 3m.y. (Gentner, Pr/ig & Smits 1953, pp. IX, 18); 25 a q- ]m.y. (Gentner, Goebel & Pr~ig 1954, pp. 124, I33); 251m.y. (Lipson 1956, pp. 149, 15o; I958, pp. I46, I47); 351m.y. (Davidson 196o, p. 334, no. 9).

Stratigraphical age. Lower Oligocene.

References DAVmSON, C. F. 196o GENTNER, W., PR3-% R. & SUITS, F. 1953. Argonbestimmungen an Kalium-Mineralien II. Das Alter eines Kalilagers im Unteren Olgioz/in. Geochim. et cosmoch. Acta, 4, 1 I-2O.

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Items

-, GOEBEL, K. & PRAG, R. x954. Argonbestimmungen an Kalium-Mineralien III. Vergleichende Messungen nach der Kalium-Argon- und Uran-Helium-Methode. Geochim. et cosmoch. Acta, 5, 124-33. LIPSON, J. I956 (see Item I2). 1958 (see Item 12). StaTS, F. & G~m'N~a, W. 195o. Argonbestimmungen an Kalium-Mineralien I. Bestimmungen an Terti~iren Kalisalzen. Geochim. et cosmoch. Acta, x, 22-7. [B. M. Funnell]

Radiometric comment. A more reliable radiometric age for these deposits would appear to be possible by considering 4°K/40Ca ratios (eft Kulp i96i , pp. 1 lO6, I i Io, x 1 I3: Item 53).

Reference KULP, J. L. x96I. B. M. Funnell

Radiometric comment. Genmer, Pr~ig & Smits (I953) add to the data of Smits & Gentner (195o). They find a relationship between the a°Ar*]4°K ratio and the crystal size of the syl,dnite, and they assume that it reflects preferential argon loss by diffusion from smaller crystals. By a curve- fitting process they deduce an age of 2 i ~ 3 m.y. for the age of the sylvlnite. Gentner, Goebel & Pr~ig (i954) , recognizing that the sylvine was at one time at a higher temperature than it is in its present environment, say that this will have accelerated the argon loss. On applying an empirical correction they deduce an age of 25 -t- ~m.y., with 2p = x5.44 × lo-lSsec -1 and Re ----- I "7 × to -xssec -x. Although physically interesting, the magnitude of the experimental error (+ 20%, --i2%) and the type of correction necessary indicate that the results do not yet provide a precise radiometric tie-point for the time-scale. A. G. Smith

(x3x-54) [Miscellaneous: New Zealand, U.S.A., U.S.S.R.] Tertiary-Cretaceous (x3x) Stock, San Juan Mountains, Colorado. Late Miocene; I6am.y. (zircon, monazite, and xenotime). (Jaffe, Gotffried & Waring x955, p. I58o; Davidson I96o, p. 334, no. 3). [No radiometric or stratigraphical details given.] (See Item I54. )

(x32) Stock, Cerrillos Hills, New Mexico. Late Eocene or Oligocene; 38a m.y. (zircon, monazite, and xenotime). (Jaffe, Gottfried & Waring I955, p. x58o; Davidson I96O, p. 334, no. io) [No radiometric or stratigraphical details given]. (See Item 154 ).

(133) Stock, Tintic district, Utah. Early Late Eocene; 48a m.y. (zircon, monazite, and xenotime). (Jaffe, Gottfried & Waring 1955, p. i58o; Davidson I96O, p. 334, no. I2) [No radiometric or stratigraphical details given]. (See Item I54).

(t34) Potosi Volcanic Series, San Juan Mountains, Colorado. Late Miocene; 26 a m.y. (zircon), i2o a and 24 oa m.y. (sphene), 24 oa m.y. (apatite). (Larsen, Keevil & Harrison 1952 , p. IO51; Davidson x96o, p. 334, no. 4) [All radiometric ages, except possible zircon age, clearly spurious; no stratigraphical details given]. (See Item 154 ).

(x35) Samples 47 & 48, Tongaporutuan, New Zealand. Upper Miocene; 35 "8a 4- 2" I m.y. & 3o'2 s 4- x .8m.y. (K-Ar glauconite). (Lipson x956 , p. 14; 1958 , pp. 146-8; Kazakov & Polevaya I958, p. 384; Davidson I96O, p. 334, no. 5 [pars]; Kulp 1959, P. 694) [Radiometric age too old (of. Evernden et al. I961, p. 83) ]. (See Item 154 )

(x36) Granodiorite, Central mountains of Kamchatka. Eocene; 55 a m.y. (K-At whole-rock). (Polevaya I957:fide Davidson i96o , p. 334, no. I4) [No details seen]. (See Item I54. )

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Items (137) Gneiss, Central mountains of Kamchatka. Eocene; 65 a m.y. (K-Ar biotite). (Polevaya 1957:fide Davidson 196o, p. 334, no. I5) [No details seen]. (See Item I54 ).

(138) Foraminiferal marl, Daghestan oilfields. Eocene; 55 a, 6o a, 6o a m.y. (3 samples: K-Ar glauconite). (Amirkhanov, Magataev & Timofeeva 1958: fide Davidson I96O, p. 334, no. 16) [No details seen]. (See Item 154).

i" (139) Spherulitic porphyry, Primorye. Eocene; 55am.y. (K-Ar whole-rock). (Polevaya I957: fide Davidson I96o , p. 334, no. 17) [No details seen]. (See Item 154 ).

t (14o)Felsitic liparite lava, Primorye. Eocene; 7oam.y. (K-Ar whole-rock). (Polevaya I957: fide Davidson I96O, p. 334, no. I8) [No details seen]. (See Item I54 ).

1" (x4x) Liparite lava, Primorye. Palaeogene; 6oam.y. (K-At whole-rock). (Polevaya x957: fide Davidson 196o, p. 334, no. 23) [No details seen]. (See Item I54 ).

t (142) Liparite tuff, Primorye. Palaeogene; 65am.y. (K-Ar whole-rock). (Polevaya I957: fide Davidson 196o, p. 334, no. 24) [No details seen]. (See Item 154).

~" (143) Quartz-porphyry lava, Primorye. tipper Cretaceous-Lower Eocene; 771m.y. (K-Ar whole-rock). (Polevaya 1957 :fide Davidson 196o,p. 335, no. 26) [No details seen]. (See Item 154).

(144) Quartz-porphyry lava, Primorye. Upper Cretaceous-Lower Eocene; 65 a and 65am.y. (K-Ar whole-rock). (Polevaya 1957:fide Davidson I96O, p. 335, no. 27) [No details seen]. (See Item z54 ).

I" (145) Quartz-porphyry tuff, Primorye. Upper Cretaceous-Lower Eocene; 981m.y. (K-Ar whole-rock). (Polevaya 1957 :fide Davidson 196o, p. 335, no. 28) [No details seen]. (See Item x54).

(m46) KAI47 (823o ft below surface) Kreyenhagen, California. Middle-Upper Eocene; 31 am.y. (K-Ar glauconite). (Evernden et al. 196I, pp. 8I, 89). [Radiometric age invalidated by excessive burial and heating]. (See Item i54 ) .

(147) ~154 (8ox2-63 ft below surface). 361m.y. (Evernden et al. 1961, pp. 8I, 89) [Otherwise as for ltem i46 ]. (See Item IO4).

(148) I~I6O (IO 79o ft below surface). 251m.y. (Evernden et al. 196I , pp. 8I, 89) [Otherwise as for Item 146].

(149] KA265 (922O ft below surface). 271m.y. (Evernden et al. I961 , pp. 8I, 92) [Otherwise as for Item 146].

(t5o) Kn267 (I2 175 ft below surface). I8nm.y. (Evernden et al. 196i , pp. 8I, 92) [Otherwise as for Item 146].

(x5x) KA285 (63II ft below surface). 331m.y. (Evernden et al. 1961, pp. 81, 94) [Otherwise as for Item 146] .

(x52) r,~162, Mathews' Landing Marl, Gulf Coast. Palaeocene or Lower Eocene; 38a m.y. (K-At glauconite). (Evernden et al. 196I, pp. 8I, 9o. [Radiometric age clearly too young]. (See Item 154 ) . t Some of these determinations may correspond to those listed in Items 332 and 334, but this cannot be ascertained from the literature available. 356 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(153) KAI70 (8150-60 ft below surface), California. Palaeocene; 46am.y. (K-Ar glauconite). (Evernden et al. 1961, pp. 81, 9 o) [Radiometric age invalidated by excessive burial and heating]. (See Item 154) .

(154) Sandstone, California. Cretaceous-Palaeocene boundary; 6oam.y. (K-Ar glauconite). (Curtis, Evernden & Lipson 1958, pp. 3, I i ; Kulp I959, P. 694) (58 4- 4m.Y.). [No details given].

References to Items I31-54 inclusive AmRKHANOV, K. I., MAGATAEV,K. S. & TIMOFEEVA, V. V. I958 (see Item I8I). CURTIS, G. H., EV~RNDEN, J. F. & LIPSON, J. 1958 (see Item 75). DAVlDSON, C. F. I96O. EVERNDEN, J. F. et al. 196 i. JAFFE, H. W., GOTTFRmD, D. & WARING, C. L. I955. Larsen-method age determinations of 15o rocks ranging in age from Precambrian through Tertiary. [Abstract] Bull. geol. Soc. Amer. 66, 158o. KAZAKOV, G. A. & POLEVAYA, N. I. I958 (see Item 12). KULP, J. L. I959 (see Item 12). LARSEN, E. S., IJ~EEVIL, N. B. & HARRISON, H. C. 1952 (see Item 40). LIPSON, J. 1956 (see Item I9). 1958 (see Item I2). POL~VAYA, N. 1. 1957. [The absolute age of some magnetic complexes as determined by the argon method.] Trudi Sessii Komissii po Oprededen~yu Absolyutnogo Vozrasta Geologicheskikh Formatsii, 4, 41-54 • lB. M. Funnell]

(x55) Snmnalt Tuff unit Oligocene/Oligocene Lowest welded tuff in section; 375 ft above base of Tertiary volcanic sequence, Sheep Pass section Egan Range, Nevada, U.S.A.

Radiometric age K-Ar (AD = 4"72 × lO-l°year-1; 2e = o'584 × IO-l°year-a) Biotite KAi75: K = 6.38%, atm. 4°Ar = 5o%, 4°Ar*#°K = o-oox88, age: 32m.y. (Evernden et al. I961, pp. 8I, 87) (~# = 4"72 x IO-a°year-1; 2e ---- o'585 x xo-l°year -1) 33.4"['m.y. (Evernden et al. I964, p. I75) Age: [32]m.y. Stratigraphical age. Limited fossil control based upon fresh-water mollusca indicates that the tufts are of Oligocene age (Evernden et al. I964, p. 175).

References EVERNDEN,J. F. et al. I96I. et al. 1964 (see Item 27). lB. M. Funnell]

(x56) Carters Limestone~ Eggleston Limestone, and Bays Formation M. Ordovlcian] Tennessee and Alabama, U.S.A. M. Ordovlcian

Radiometric age (I) s88U-~°ePb (2 = I'537 × IO-l°Year-l) (i) Zircon concentrate from bentonite bed (Edwards et al. 1959; Adams et al. I96O) Incorrect value (Evemden 1964, personal communication). 357 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Pb U Isotopic composition oflead (%) Sample (g/gx lO-S)(g/gX l°-e) 2°*Pb 2°sPb 2°Tpb 2°sPb OH-22 34"5 320 0"387 69"680 9"585 25"347 CH-24 29"7 314 0"277 70"762 8"239 20"722 CH-I7 26"7 317 O"157 75"317 6'855 17"670 OH-7 27"2 335 O'2I 9 72"220 7"396 20"I65

Sample Locality Stratigraphical age Age (m.y.) cI~-22 Alexandria, Tennessee ~ Carters Limestone, 452ai IO m.y. OH-24 Dowelltown, Tennessee f 446a4 - IO m.y. OH- 17 Nashville, Tennessee Stones River Group 438a4- I o m.y. oH- 7 Vonore, Tennessee Bays Formation 453 a4- I o m.y.

(ii) Zircon concentrate from bentonite bed (Tilton, quoted by Adams et al. 196o )

Concentrations (g/g × lO 8) 23sU 935U *08pb* 207pb* 208pb* 313 2.24 19.24 1.124 3" lO3

Isotopic composition of lead 2o4pb 2oepb 207pb ~ospb Observed i. ooo 391 37 "27 97" 57 Corrected for blank I "ooo 667- 3 53"35 141 "7

Alabama, Carters Limestone: age: 445 a 4- IO m.y. Mean of (i) and (ii) : 447 a [4- 3] m.y.

In (i), concentrates of fresh, euhedral zircon crystals were used. Common lead contamination in the laboratory was estimated at less than 25%. The common lead correction, obtained from Chow & Patterson's (I959) data Oll modern oceanic lead, was extrapolated back to Middle Ordovlcian time in the manner described by Collins, Russell & Farquhar (1953). The correction is 36 to 4o% for 2°Tpb, and 4 to 1 I% for 2°ePb; only e3su-2°6pb ages are therefore accepted as reliable. For (ii) the 235U-~°TPb and the 2°TPb-e°ePb ages are rejected for reasons similar to those in (i) above.

(2) K-Ar (constants not given) (i) Biotite from bentonite bed (Faul, quoted by Adams et al. 196o): Pyne Mine and Wenonah No. 8 Mine, near Bessemer, Alabama.

Carters River Limestone K (%) 4°Ar* (ppm) ~°Ar*/4°Art°t 4°Ar*/4°K Age (m.y.) "232 o.81 [o-o274] 42o [419] Pyne 6- 94 ~oo. 233 o- 9o [o. o275] -- [42ol Wenonah No. 8 6"23 {o'209 0"77 [0"0275] -- [42o] • 207 o. 85 [o.o272] -- [416] Average: 419 4- 5 [4- 2] m.y.

(ii) As in (a) (Curtis & Evernden, quoted by Adams et al. I96O): age: 421 4- 5m.y. 358 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(3) Rb-Sr (it = "47 × Io-nYear-a) (i) Biotite in bentonite (Adams et al. ,958; recalculated by Faul i96o ) OH-27 Alabama, Carters Limestone; age: [492]m.y. (it = I'39); 466 b 4- 5om.y. (it = "47). GH-3I Tennessee, Eggleston Limestone; age: [448], [475]m.y. (;t = 1 "39); 424 b 4- 5om.y.; 45ob 4- 5om.y.; (it = I'47). (ii) Biotite in bentonite (Tilton, quoted by Adams et al. I96O ) : Wenonah No. 8 mine, Alabama, Carters Limestone.

Rb (ppm) STRb (ppm) STSr* (ppm) STSr*/total Sr STSr*/S'Rb 217.8 86 o.568 o. I49 [o.oo66o]

Age: [473] m.y. (it ---- 1-39) ; 447 4- 4 ° m.y. (it = 1.47). Mean Rb-Sr age: [473] m.y. (it = 1.39); 447 4- [7] m.y. (it = 1.47 ).

Stratigraphical age. Middle Ordovician.

R~f6rence$ ADAMS, J. A. S., EDWARDS, G., H~NL~, W. & OSMOND, K. 1958. Absolute dating of bentonites by strontium-rubidium isotopes. [Abstract] Bull. geol. Soc. Amer. 69, I527. , OSMOND,J. K., EDWARDS, G. & HFNLE, W. I96O. Absolute dating of the Middle Ordovician. .Nature, Lond. 18,8, 636-8. CHow, T.J. & PATTFRSON, C. C. 1959" Lead isotopes in manganese nodules. Geochim. et cosmoch. Acta, 17, 21- 3I. COLLINS, C. B., RUSSELL, R. D. & FARO.UHAR, R. M. I953. The maximum age of the elements and the age of the Earth's crust. Ganad. 07. Phys. 3 x, 4o2-I8. EDWARDS, G., H~NLF, W. H., OSMOND, J. K. & ADAMS,J. A. S. 1959. Further progress in absolute dating of the Middle Ordovician. [Abstract] Bull. geol. Soc Amer. 7o, I596. FAUL, H. I96O. --- & THOMAS, H. H. 1959 (see Item 94)- [A. G. Smith]

Radiometric comment. Holmes (1959) gave, but did not use, the values of Edwards et al. (I959) for 2ssU-z°6Pb ages on zircons. He averaged Rb-Sr ages on biotites given by Adams et al. (I958) to 475m.y. (it = I "39 × Io-llYear-l) and used it as a point on the time-scale. Faul (i96o) quoted most of the above data, and corrected the Rb-Sr values, using it = I "47× Io-UYear-L Kulp (I961) used only ~3sU-~°nPb ages, quoted as 447 + Iom.y. Because eoncordmlce between U-Pb and Pb-Pb ages has not been demonstrated, the sigtfificance of the 28sUJ°6Pb age is uncertain, although it agrees well with the Rb-Sr age for itRb = I "47 × IO-11Year-l"

References HOLMES, A. 1959. KOLP, J. L. 196 i. A. G. Smith

Stratigraphical comment. According to Cooper (1956), the Carters Limestone and Bays Formation are contemporary facies of late Wilderness age, and the Eggleston Limestone, with two thick metabentonites in the upper part of the succession, is a top member of the Wilderness Series.

R~f ence CooPER, G. A. 1956. Chazyan and related brachiopods. Smithson. misc. Coll. xz7, I-IO24. A. Williams

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Items

Stratigraphical comment. Carters Limestone and Bays Formation appear to be stratigraphical equivalents. On the graptolitic scale, Berry (I96O, p. IO5) would put the corresponding Wilder- ness Stage in the period between the N. gracilis Zone and D. clingani Zone, i.e., early Caradocian. This agrees with Williams's (I96 % p. 59) correlation through the Girvan succession.

References BFRRY, W. B. N. 196o. Correlation of Ordovician graptolite-bearing sequencies. Int. geol. Congr. ,,x (7), 97 -1°8. WILLIAMS, A. t962. The Barr and Lower Ardmillan Series (Caradoc) of the Girvan district, south-west Ayrshire, with descriptions of the Brachiopoda. Mem. geol. Soc. Lond. 3. I. Strachan

(157) Bentonltes in Chasmops Lixnestone M. Ordovician/M. Ordovician Kinnekulle, Sweden.

Radiometric age K-Ar (~B -----4"76 × IO-x°year-1; ~e ---- o'589 × Io-l°year-1; 4°K/K = o.oii8 at. %)

Sample Description Horizon K20 (%) 4°Ar*/4°K Age (m.y.) Biotite 82 Almost unaltered flakes A1 5"37 o'o287 434 77 Coarse, somewhat chloritized A2 4'43 o'o3o3 453 59 Strongly chloritized B 3"48 o-o288 434

Sanidine 61 With illitic aggregates B I o. 96 o. o3o 4 455 9o Pure B I i. i6 o-o296 445 I46 Pure B 12" o8 o. o292 44o

The samples come from a mine and have not been exposed to present-day weathering processes. The stratigraphical section is autochthonous, thin, and flat-lying, and is unlikely to have been deeply buried or metamorphosed. Although a post-Silurian (Permian ?) sill lies loom above the bentonites, the clays in them are still montmorillonite-rich and do not appear to have been thermally affected, which suggests that argon loss by heating has also been small. Mean age: 444 [4-4] m.y.

Stratigraphical age. The samples come from three bentonite horizons: B (base) about 2 m thick, separated by 25cm interval from A2 (I5cm), in turn separated by a few centimetres from At (l 5 era). All lie at the top of a 7-m section containing bentonites. Poorly definitive trilobites, ostracods, and graptolites occur in and below the bentonites. Dicranograptus clingani occurs in a black shale 3 m above A. Thorslund (1948) assigned a probable Diplograptus modestus age to the bentonites (Caradocian).

References BYSTR6M-ASKLUND, A. M., BAADSGAARD, H. & FOLINSBEE, R. E. I961. K/Ar age of biotite, sanidine, and illite from Middle Ordovician bentonites at Kinnekulle, Sweden. Geol. F6ren. Stockh. F6rh. 83, 92-6. THORSLUlWD, P. In WEARN, B., THORSLUND, P. & HEMMINGSMOEN, G. I948. Deep boring through Ordovician and Silurian strata at Kinnekulle, Vesterg6tland. Bull. geol. Instn Univ. Uppsala, 32, 343. [A. G. Smith] 360 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. The bentonite samples come from bands within the Chasmops Limestone: the horizon appears to be high in the Ludibundus Stage of Sweden (Clxt of Estonia). A. Williams

(I58) Brassfield L/n~estone Silurian/Ordovician Adams County, Ohio, U.S.A.

Radiometric age K-Ar ()l~ = 4"72 × Io-X°year-1; ;re ----- o'585 × Io-l°year -1) Glauconite G3347: K = 3-oi%, air corm = o%, 4°Ar*#°K = o'o272, age: 41o [416] m.y. (No stratigraphical or collecting information given.)

Rgference Hug~Y, P. M. et al. I96o (see Item I3). [I. Strachan]

Stratigraphical comment. The Brassfield Limestone is 40 to 5oft thick in this area. It is probably of Middle or lower Upper Llandovery age. This is the only Silurian age given in Kulp (I96 i). I. Strachan

(159) Binnewater Sandstone L. Devonian/U. Silurian High Falls, on Rondout Creek, Catskills, N.Y., U.S.A. [4 I° 5O'N, 74 ° XO'W].

Radiometric age K-Ar (Stp= 4"72 X IO-l°year-a; ~te = 0"585 × Io-l°year -1) Glauconite c 3277: K = 3"54%, air corm ---- 2t%, 4°Ar*/4°K = o'oi55, age: 247m.y.

Stratigraphical age. The Binnewater Sandstone is given as Upper Silurian or Lower Devonian in age.

Reference HUaL~Y, P. M. et al. I96o (see Item x3). [I. Strachan]

(x6o) Pitchblende, ~h;nle Formation /Triassic Petrified Forest Member, Alyce Tolino mine, Cameron, Arizona, U.S.A. [35 ° 5I'N, I II ° 24'W].

Radiometric age ~35U_207pb Pitchblende KI78: 2°6Pb/~saU ---- o-oi98 -4- 0"0004, 2°TPb/~asU = 0"236 4- 0"005, a°Tpb/2°6Pb ---- o'o879 4- o'o35, age: 218 a 4- 5m.y. (Miller I96o , pp. 39, Io2). Miller (I96O) provides many 235U-~°TPb dates for the uranium ores from the Chinle Formation. They range in age from 2oam.y. to 218" 4- 5m.y. Miller & Kulp (I958, p. 941) give one Chinle "3sU-2°~pb date as high as 295 a 4- 2o m.y., but this is not referred to in the later report. Miller (196o , p. I2o) states that 'the 285U-2°TPb dates are probably reliable minimum ages'.

Stratigraphical age. According to Colbert & Gregory (in Reeside et al. I957, PP. I462-3) the verte- 36[ Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns brate fauna of the Petrified Forest Member of the Chinle 'is certainly Upper Triassic, or Keuper •.. perhaps ... representing a middle segment of the Upper Triassic or Keuper sedimentation [in North America].

References MILLER, D. S. I96o. The isotopic geochemistry of uranium, lead and sulfur in the Colorado Plateau uranium ores. Ph.D. thesis, Columbia University (University Microfilms Inc., Ann Arbor & London). 134 PP. & KULP, J. L. 1958. Isotopic study of some Colorado Plateau ores. Econ. Geol., 53, 937-48. REESIDE, J. B. Jr. (Chairman) et al. 1957- Correlation of the Triassic formations of North America, exclusive of Canada. Bull. geol. Soc. Amer. 68, 145 I-514. [E. T. Tozer]

(x6x) [Incorporated into Item Io]

(x62) Basic lava, dykes, and sills, England Triassic/Carboniferous [For full analytical and stratigraphical details see pp. I59-73.]

Radiometric age K-Ar (~p = 4"72 × xo-l°year-X; 2e = 0'584 × IO-l°year-x)

Rock-type and locality 4°Ar*#°K Age (m.y.) (I) Olivine-basalt lava, Masson Hill, Derbyshire [o'oi39] 2254-I4 (2) Olivine-dolerite dyke, Bartestree, Herefordshire [o.oi62] 26o4-2o (3) Zeolitized olivine-dolerite sill, Kinlet, Shropshire [o. o 166] 264+ 8 (4) Olivine-dolerite intrusion, Rowley Regis, Birmingham [o.oi66] 2664-8 (5) Olivine-dolerite sill, Pouk Hill, near Walsall, Staffordshire [o'ox67] 2674-22 (6) Olivine-dolerite dyke, Bartestree, Herefordshire [o.ox8o] 2864- I8 (7) Olivine-dolerite sill, Clee Hill, Shropshire [o.oi87] 2954-5 (8) Flow-aligned olivine-basalt intrusion, Carlton Hill, Derbyshire [o. o 186] 295 4-14 (9) Olivine-basalt sill, Dosley, Coalbrookdale, Shropshire [o. o z87] 296 4- I i (1 o) Olivine-basalt sill, Lyddebrook Dingle, Coalbrookdale, Shropshire [o- o x87] 296 4- I o (I I) Zeolitized olivine-dolerite dyke, Brockhill, Worcestershire [o'oi94 ] 3o64-6 For analytical details see pp. 162-6.

Stratigraphical age. Carboniferous-Triassic (see Fitch & Miller z964).

Ptgfefe?/ce FrrcH, F. J. & MILLER, J. A. i964 . The age of the paroxysmal Variscan orogeny in England. Quart. J. geol. Soc. Lond. xao s [this volume], 159-73. IF. J. Fitch & J. A. Miller]

(t63) Maardu Deposit Ordovician/Ordovician Esthonia, U.S.S.R.

Radiometric age K-Ar (~p = 4"9 × IO-x°year-1; ~e = 0.602 × IO-l°year-x) 362 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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K (%) 4°Ar*/'°K Age (m.y.) Glauconite: 6.65 o'o3oo 435 [454] o'o3o3 44o [458] o'o295 43 ° [448]

(Kazakov & Polevaya x958, p. 381) Mean age: 435 [453] m.y.

Stratigraphical age. From Ordovician glauconitic sandstones in shaft No. 5, Maardu Deposit, Esthonian S.S.R. The sandstones contain Orthis recta Pander and Megalaspis leuchtenbergi Lamarck. The age is given as 'O1'.

R~re~# KAZAKOV, G. A. & PO~VAYA, N. I. x958 (see Item t2). [A. G. Smith]

Radiometric comment. Holmes (x959) quoted ages of 445m.y., 45om.y., and 455m.y., but did not use them. Davidson (x96o) quoted 474m.y. and 48x m.y.

Rgfoe~e$ DAVmSON, C. F. I96o. HOLMES, A. x959. [A. G. Smith]

Stratigraphical comment. 'Orthis recta Pander' is probably Angusticardinia recta (Pander), which, with Megalaspides [=Megalaspis part] spp., occurs in B1/~ of Estonia. A. Williams

(x64) Bertie Formation U. Silurian/U. Silurian Top of Scajada Member, Ontario County, N.Y., U.S.A.

Radiometric age K-At (constants not given) lllite 3946: K = i "43%, air corrn = 25%, 4°Ar*/4°K = 0-0208, age: 326m.y.

Stratigraphical age. Upper Silurian [probably Lower Ludlovian].

R~fgfence Hugr.ry, P. M. et al. x963 (see Item 48). [I. Strachan]

Radiometric comment. See Items 48 and x68. I. Strachan & A. G. Smith

Stratigraphical comment. Ruedemann (x 947) records Climacograptus ultimus from the Bertie Waterlime. I have examined the type-specimens and they are certainly not climacograptids. They look very similar in outline to Gothograptus nassa although no reticulate structure is demonstrable. The age of the Bertie Formation is usually given as Lower Ludlow, and this evidence merely confirms this view. 363 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Reference Rt~D~.MANN, R. x947. Graptolites of North America. Mem. geol. Soc. Amer. z 9. I. Strachan

(x65) C~tmlllus Formation U. Silurian/U. Silurian Genesco County, N.Y., U.S.A.

Radiometric age K-At (constants not given) Illite 3943: K = 4"7o%, air corrn -~ 6%, 4°Ar*/4°K = o.o212, age: 332m.y.

Stratigraphical age. Upper Silurian [probably Lower Ludlovian].

Reference HuRra~x', et al. x963 (see Item 48). [I. Strachan]

Radiometric comment. See Items 48 and x68. I. Strachan & A. G. Smith

Stratigraphical comment. The Camillus Formation underlies the Bertie Formation.

Reference. See Item I64. I. Strachan

(x~) Roclhester Shale M. Silurian/M. Silurian Base of Rochester Shale, Rochester, N.Y., U.S.A. [43 ° xo'N, 77 ° 4o'w].

Radiometric age K-Ar (constants not given) Illite 3947: K = 5"36%, air corm = IO%, 4°Ar*/4°K ----- o'o234, age: 363m.y.

Stratigraphical age. Middle Silurian [probably Lower Wenlockian].

R~f erence HURLEY et al. I963 (see Item 48). [I. Strachan]

Radiometric comment. See Items 48 and x68. I. Strachan & A. G. Smith

Stratigraphical comment. The Rochester Shale contains only dendroid graptolites but is stratigraphically a little higher than the Williamson Shale.

Reference. See Item I64. I. Strachan 364 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(t67) Will~*ttson Shale M. Silurian/M. Silurian Base of Williamson Shale, Rochester, N.Y., U.S.A.

Radiometric age K-Ar (constants not given) Illite 3942: K = 5"58%, air corm = 7%, 4°At*/4°K = o-o23% age: 357re.Y.

Stratigraphical age. Middle Silurian [sic; probably low Upper Llandovery]. Reference HURLEY et al. I963 (see Item 48). [I. Strachan]

Radiometric comment. See Items 48 and I68. I. Strachan & A. G. Smith

Stratigraphical comment. Ruedemann (I947) records Monograptus becki Barr., M. clintonensis (Hall), M. runcinatus Lapworth and Retiolites geinitzianus var. venosus (Hall) from the WiUiamson Shale, which he correlates with the M. turriculatus zone in Britain, i.e., low in the Upper Llandovery.

Reference. See Item I64. I. Strachan

(168) Sodus Formation M. Silurian/M. Silurian 5½ft above base of Sodus Formation, Rochester, N.Y., U.S.A.

Radiometric age K-Ar (constants not given) lllite 3941: K = 6.o8%, air corm = I%, 4°Ar*]4°K = o.0237, age: 367m.y.

Stratigraphical age. Middle Silurian [sic; probably low Upper Llandovery].

Reference HURLEY et al. 1963 (see Item 48). [I. Strachan]

Radiometric comment. All these five samples, Items I64-8, give ages much too young for the standard succession. See also Item 48 . I. Strachan & A. G. Smith

(169) Glauconltlc limestone L. Ordovician/L. Ordovician Limestone quarry xokm south-east ofFalk6ping, Vesterg6tland, Sweden [58 ° 1o' N, 13 ° 32' E].

Radiometric age Rb-Sr (;L = 1 "39 × I°-nY ear-l) sTSr (ppm) sTSr*/STRb ( × lO 5)

Rb t°t (ppm) S7Rb (ppm) Sr (ppm) I.D. I.R. I.D. I.R. GL-3 311 87"8 I2" 9 o.46 -- 525 -- GL-I I 307 86 "9 16- 7 o. 51 o.45 585 520 365 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems Age (m.y.) 2 = 1.39 2=1.47 GL-3 (I.D.) 3804-35 [356 ] GL-I I (I.D.) 4204-65 [397] GL-I I (t.R.) 3754-~9 [353] Mean: 392 [369-4-17]

(I.D., isotope dilution analysis; t.R., isotope ratio analysis)

The glauconite (x-2mm grains) constitutes more than 50% of chips analysed, the remainder being crystalline calcite and limestone fragments. The samples were obtained from an abundantly fossiliferous pyritic limestone. The authors believe the glauconites are either essentially authigenic; or, if formed from biotite, were completely reconstituted, since even a small amount of inherited radiogenic S~Sr would have made the determined age unreasonably high.

Stratigraphical age. The glauconite comes from the richly fossiliferous basal member of the Ordo- vician. The uranium-bearing 'kolm' oil shales (Item 34) are exposed in the same quarry a few tens of feet below the glauconite-bearing bed.

References CORMmR, R. F. et al. I956 (see Item 13). HERZOG, L. F., PmSON, W. H., Jr., & CORMmR, R F. I958 (see Item I2). [A. G. Smith]

Stratigraphical comment. The glauconitic limestone from which the sample was taken is either highest Tremadoc or earliest Arenig in age, i.e., top of D or lowest E of section I, fig. 6 of Tjernvik (I956, p. I23).

R ff gfcRc e TjEaNVm, T. E. I956. On the early Ordovician of Sweden: stratigraphy and fauna. Bull. geol. Instn Univ. Uppsala, 36, IO7-284. [H. B. Whittington & A. Williams]

(17o) Granite, south Quebec ? M. Silurian/M. Ordovician Granite in Thefford Mines-Black Lake area, Quebec, Canada. No. 516:460 o 4' OO"N, 7 I° 17' 48'' w; No. 591 : 46o o2' I9"N , 7 I° 2I' I6"w.

Radiometric age K-Ar (2# = 4"715 × Io-l°year-1; ~.e = 0"585 × Io-l°Year-x)

K (%) 4°Ar* (%) 4°Ar*#°K Age(m.y.) Muscovite Quartz-monzonite 516: 8.25 99 o'o32I 48I Pegmatitic granite 591 : 8- 23 I oo o'°318 477

Stratigraphical age. The granitic rocks are small cataclastic stocks and dykes cutting ultramafic rocks and wholly confined to them and their margins (Riordon I954). The ultramafic rocks intrude the youngest strata in the area, the Beauceville Group, which contains assemblages of graptolites said by Berry (I962) to indicate the Wilderness-Trenton stages of the Appalachian successions (Cooper I956; Riordon 1954, I962 ). Many miles south-east of the ultramafic belt, Middle Silurian rocks unconformably overlie such Ordovician rocks (Neale et al. I96I ). Poole, 366 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Bfiland & Wanless (I963) believe that the ultramafic intrusions were emplaced only shortly before the granite during the same stratigraphical time-interval. The authors offer two alternative interpretations: (i) that the ages represent the time of intrusion and crystallization of the granites, thereby giving a firm minimum age to the Upper Trenton Stage; or (ii) that the ages are those of micas formed much earlier below their present structural level, incompletely degassed during later intrusion as solid masses.

References B~RRY, W. B. N. I962. On the Magog, Quebec graptolites. Amer. J. Sci. ~,6o, I4~,--8. COOPER, G. A. I956 (see Item I56 ). N~AI~, E. R. W., B~.LAND, J., POTTER, R. R. & POOLE, W. H. I96I. A preliminary tectonic map of the Canadian Appalachian region based on age of folding. Bull. Canad. Min. Metall. 54, 687-94. POOL~, W. H., BCLAND, J. & WANLESS, R. K. x963. Minimum age of Middle Ordoviciart rocks in southern Quebec. Bull. geol. Soc. Amer. 74, I o63-6. RIORDON, P. H. 1954" Thetford Mines-Black Lake area, Frontenac, Megantic, and Wolfe counties. Prelim. Rep. Quebec Dep. Min. 295 , 23. -- I96~,. Geology of the asbestos belt in south-eastern Quebec. Bull. Canad. Min. Metall. 55, 31 I-x3, 5oo. [A. G. Smith & A. Williams]

Stratigraphical comment. The restriction of the stocks and dykes to the ultramafic rocks, their cataclastic texture, and poor agreement with other Middle Ordovician dates (Items 156, x57) suggest that the second interpretation is correct. A. G. Smith

Radiometric comment. The minimum date for the Upper Trenton Stage afforded by this determination is 35m.y. earlier than Kulp's (I961) estimate of 445m.y. According to Poole, Bfiland & Wan.less (x963) the only possible reason for this discrepancy is that the igneous masses may have become coherent bodies below their present level much earlier in the Ordovician and were subsequently emplaced as solids in post-Trenton time. A. Williams

(t7x) Vosges granites U. Carboniferous/L. Carboniferous Localities (French co-ordinates): (x) Andlau 53077.2N, 5G62.8~.; (5) Lac Blanc 53046.ON, 5024.85E; (9) Natzviller 53083.55 N, 5056. I~; (I I) Hohwald 53077.6N, 5G54.95E; (I4) Col de Grosse Pierre 53o36.2N, 5OO5.5E; (I7) Ranspach 5302o.4 N, 502o.o~; (I9) Willer-sur-Thur 53 ° 15. ON, 5G23 . 8~.; (20) Liepvre 53o62 • 9 N, 5G5o . 7E; (22) Kalbplatz 53o56 . 85 N, 5045 . 2E.

Radiometric age K (%) 4°Ar* (ppm) '°Ar*/4°Art°t 4°Ar*#°K Age (m.y.) Biotite (i) Andlau 6-30 o. 146 0"70 [0"01900] 300 [300] (5) Lac Blanc 7"41 o-I8o 0-86 [o.oi99i ] 315 [313] (9) Natzviller 6.24 o. I57 o-88 [o-o2o62] 325 [324] (I x) Hohwald 4"52 o. 11 x o'54 [o'o2oi3] 315 [317] (I4) Grosse Pierre 6.82 o. 167 o-89 [o-o2oo7] 32o [3 t6]

Rb-Sr (2 = I "475 × Io-ltyear-1; 87Rb/Rb = o'283g/gRb, sTSr (normal)/ssSr ----- 8"5 at.%)

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STRb S'Sr* Age (m.y.) (ppm) (ppm) S'Sr*]Total S~Sr 8~Sr*]STRb ~=I.39 /t----I "47 Biotite, except where stated (5) Lac Blanc 3 I8 I -5 o o" 74 [o" oo472 ] [339] ~o.~,f [32o] 322 I" 55 o- 75 [o" 00481 ] [345] f°'"'], [326] (9) Natzviller 223 I'O8 o'45 [o-oo484] [347] 325 [328] (14) Grosse Pierre 253 1"17 o'73 [o'oo462] [332]~ o ('[314] ~250 l'II 0"72 [0"00444] [319]J 3 5~. [3OI ] (17) Ranspach 313 1"47 0"77 [0"00470] [337] 320 [319] (St. Amarin) (I 9) Wilier, biotite, 127 o. 6 lO o" 51 [o. 00480 ] [344] 325 [326] muscovite 53"4 °"13 o-o15 [o'oo243] [175] -- [165] (2o) Liepvre, biotite, 173 o'767 o'71 [o'oo443] [318] 3oo [3Ol] muscovite 75"7 o'4x o'074 [o"oo542] [389] (37o) [368] (22) Kalbplatz (Brezouard),biotite 576 2"52 o'92 [o'oo437] [314] 295 [297] muscovite 382 1.69 o.92 [o-oo442] [317] 3 °o [3 °°]

Stratigraphical age. These granites were formerly believed to be post-Tournaisian and pre-Vis6an and were thought to provide a precise datum in time-scales (Holmes 1959; Faul I96o; Kulp 196 i). But according to Corsin & Ruhland (1959) they are post-lower Vis6an and pre-Stephanian. Faul & Jiiger (1963) have suggested that these and the granites of the Schwarzwald and the Massif Central fall into two time-groups around 3oom.y. and 32om.y., the older group being late Vis6an and the younger later Westphalian or early Stephanian.

References CORSlN, P. & ROHLAND, M. I959. Les gisements ~ plantes du Vis6en dans les Vosges m6ridionales. C.R. Acad. Sci. Paris, 248, 2 I45- 9. FAUL, H. 196o. & JAGER, E. I963 . Ages of some granitic rocks in the Vosges, the Schwarzwald, and the Massif Central. J. geophys. Res. 68, 3293-300. HOLMES, A. 1959. KULP, J. L. i96I. [E. H. Francis]

Radiometric comment. The authors suggest that the dates fall into two groups: c. 3oom.y. and c. 32om.y. When the calculations are carried to three significant figures and the half-life of 1 "47 × 1o-1°Year-a is used for Rb-Sr ages, there are no ages in the range 3o2 to 312m.y., and the mean ages of each group are 3oo :tz o'5 m.y. and 32o -4- 2 m.y. It would be interesting to know whether or not the field-relations show evidence of two intrusive phases. A. G. Smith

(x72) Upper Vis~an tufts, France L. Carboniferous/L. Carboniferous (1) Malavaux tufts, near Cusset, Allier. Specimen 202 from Dupr6 quarry at Malavaux. (2) Ch~teauneuf-les-Bains, Puy-de-D6me. Specimen 209 from quarry on the right bank of the Sioule, 200 m upstream from the bridge carrying Route n. [O9 between Ch~teauneuf and Lisseuit. Specimen 2 lO from debris at road works on Route D. I22 between Blot-L'Eglise and Ch~teauneuf. 368 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometric age Rb-Sr (4 = I "47 × I°-XXyear-a; 8VRb/Rb = 27"85 at. %; s'Sr/Sr = 7"o2 at. %)

S'Rb s~Sr* Age (m.y.) (ppm) (ppm) sTSr*/S'Sr t°t 8~Sr*/s~Rb 2="39 4=I"47 Biotite (50% (x) I47 o" 745 o" 27 ° [o'oo5o7] [364] [344] chloritized) in I49 o" 707 o" 263 [o" 00474] [34o] [322] rhyolitic tufts (2) I5," ~ 0.7, 6 o.267 [o'oo47I ] [338] [320] 202 '539 ,3284-5 (3) 154 o" 727 o" 260 [o" 00472 ] [339] [320] 15o o. 735 o" 262 [o' oo49 o] [352] [332] (4) 151 o" 7 ' 6 o" 268 [o" 00474] [34o] [322] . ' 49 o" 724 o" 250 [o" 00486] [349] [33 °] Biotite (50% chloritized) in rhyolitic tufts ~ (i) 87 .4~ ° [o. oo476 ] [345] 87 .IJ "4'5 0"055 [323] t 209 3](2) 84"9 0"4,, 0"055 [o. oo484] [347] [328] 324±0 '4 L 86.3 o-4o6 o.o54 [o .oo471 ] [338] [320] Biotite (Ioo% chloritized in rhyolitic tufts)

210 f(') '03 0"5'4 0"I28 [o. 00499] [358] I. IO4 o'5oi o- I32 [o'00482] [346] [327][339] )334+36

Mean age: [346] m.y. (4 = I. 39) ; 328 4- 3m-y. (;t = I'47).

(See radiometric comment, Item 63)

Stratigraphical age. The Malavaux tufts form part of the Ardoisi6re basin to the east of the Limagne plain. They are interbedded with shales said to contain Productus giganteus and P. latissimus and to indicate a D, horizon near the top of the Visdan. The Ch~teauneuf tufts occur in the Manzat basin, west of Limagne, among beds that, though un£ossiliferous, have always been correlated with those of Malavaux.

Rff~?'CnCg

BONHOMME, M. et al. I96z (see Item 63). [E. H. Francis]

(x73) Grs~nlte de G|en-sur-C~re L. Carboniferous/L. Carboniferous 4km south of Lac de Settons, Ni~vre, France. (I) Quarry at Gien-sur-Cure, on route D.29O (Vialette i96x ). (2) Quarry facing the 'Morvan' works on the road from Ch~teau-Chinon to Arleuf (Despois, Sanselme & Vialette i963).

Radiometric age Rb-Sr (4 = I "47 × Io-nyear-1; STRb/Rb = 27"85 at. %; STSr/Sr = 7"02 at. %) 369 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Age (m.y.) Rb (ppm) Sr prim S7Sr* sTSr (%) s7Sr*/S7Rb it=i.39 it = I"47 Biotite (l) (i) 637 o-852 43 [o. 00472 ] [339] [320] "] (ii) 588 0-827 45 [0"00497] [357] [337][ 592 o" 846 46 [o" 00504] [362] [342] ~" 334 4- 7 (iii) 580 o" 803 44 [o" o0489] [351 ] [332] | 577 o. 789 43 [o" oo483] [347] [328] J (2) (i) 274 2I o'37I "] ~" [0"00478] [343] [324] 326-319 279 22 o'[3176t ~ ~ [o'oo476 ] [342] [323] 33o-324 (ii) 265 2I o'38o 20 [o'oo5o6 ] [362] [343] 345-342 267 19 o. 368 j [o'oo487] [349] [33 o] 334-33 t t Given as o. 576 in original, but the corresponding ages indicate that this is incorrect.

Age: [35o]m.y. (2 = I'39); 334 ± 7 [+ 3]m.Y • (2 = I'47 )

Stratigraphical age. The granite was assumed by Vialette (x 96 i) to cut Lower Visfian sediments and to be overlain by Upper Vis~an. But according to Despois, Sanselme & Vialette (1963) it is a trachyandesitic tuff of Lower Vis6an age that has been granitized during emplacement of the Settons granite (328 4- 4m.y.). On either interpretation this must be taken as an infra-Vis6an date.

References DvsPoxs, J., SANSELME, H. & VIALF.TTE, Y. 1963 (see Item II9). V]ALEW'I~, Y. 196I. Age absolu du granite vis6ert de Gien-sur-Cure (Ni6vre) dans le Massif Central fran~ais. C.R. Acad. Sci., Paris, 252 , 4o18-I9 . [E. H. Francis]

(x74) Hercynlan granites, Erzgebirge Mountains L. Permian/L. Carboniferous East German-Czech border.

Radiometric age K-Ar (2p = 4"72 × Io-l°year-1; ~ = 0"556 × Io-l°year -1) 4OAr* K (%) (cm 3 × io 5) 4°Ar*#°K Age (m.y.) Saxony, Eibenstock 7" 8 io. 8 [o- 0203] 350 [3 i9] Kirchberg 7"4 I x.2 [o.o222] 365 [346] Kirchberg 5"o 7"2 [o.o21I] 36o [33 I] Bergen 7"65 i 1-6 [o-o222] 37 ° [346] Czechoslovakia, Naydek massif 6- 8 8.9 [o. o 192] 33 ° [3o3] Czechoslovakia, Karlovy Vary 7" 15 9"9 [o" o2o3] 34° [319]

Mean age" 35 ° [328 ~ 7] m.y.

Stratigraphical age. These masses are said to be granitoids intruding Lowest Carboniferous and unconformably overlain by New Red Sandstone (Lower Permian) rocks. 370 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Reference VINOORADOV, A. P. & TUOARINOV, A. I. 1961. Some supplementary determinations of absolute age (towards a universal geochronological scale). Dokl. Acad. Sci. U.S.S.R. x34 , 917-21. [Translation from C.R. Acad. Sci., U.R.S.S. x34 [I96O ] (5), I I58-6I. [E. H. Francis]

Stratigraphical comment. The Variscan granitoid masses of Saxony and Thuringia are thought to represent the uppermost dome-like elevations of an almost continuous magmatic layer. Intrusion was recurrent and related to the various phases of the Variscan folding, and in the case of the Krusne Hory complex (represented by the above analyses) ranged from Sudetic to Asturian, i.e., from early to late Upper Carboniferous. Although the mean age is [328] m.y., a range of dates is to be expected since individual plutons themselves are complex.

Reference ZOUB~K, V. (ed.). I96o. The Variscan granitoid magrnatism of the Czech massif. In Tectonic development of Czechoslovakia. Prague. A. W. Woodland

(x75) Enoggera granite ? Triassic/L. Palaeozoic Sterling Granite Co. quarry, Ashgrove, Brisbane, Queensland, Australia [27 ° 25's, 1520 48's].

Radiometric age K-Ar (AB = 4"72 × IO-l°year-1; ire = o'584 × IO-l°year -1) Biotite: K ---- 2"35%, 4°Ar*#°K ----o'o136, age: 219m.y.

Stratigraphical age. Permian or early Triassic.

Reference EVERNDEN, J. F. & RICHARDS, J. R. 1962 (see Item 65). [D. B. Smith]

Stratigraphical comment. The Enoggera granite is a sharply discordant stock that intrudes the Lower Palaeozoic Brisbane Schists. According to Bryan (1915) , this granite was intruded in two phases: early quartz-diorite and granodiorite, followed by biotite-granite. It is presumed that the biotite-granite is the rock analysed. Jones (1948) associates the intrusion of the granite with an unnamed orogenic episode ( ? the Hunter-Bowen orogeny) and states that, although an age later than the Brisbane Tufts is not definitely excluded, local evidence suggests that the tufts post-date the granite. Apart from a thin patchy basal sedimentary deposit, the Brisbane Tufts are the lowest member of the Ipswich Coal Measures, considered by Bryan & Jones (I96O) to be of Middle Triassic age. David (I 95o), however, suggests correlation of the Ipswich Coal Measures with the middle and upper part of the Narrabeen Series of New Wouth Wales, the fauna and flora of which indicate a Lower Triassic age. If this view is correct, the earliest rocks thought to post-date the Enoggera granite are of approximately low-mid to mid-Bunter age, slightly younger than the earliest beds thought to post-date the Stanthorpe granite (225m.y. : Item 69).

References BRYAN, W. H. 1915. Geology and petrology of the Enoggera granite and the allied intrusives. Part I, general geology. Proc. roy. Soe. 0d, 26, I41-62. ----- & JONES, O. A. 196o. Brisbane and south-east Moreton. In The geology of Queensland (ed. Hill, D. & Denmead, A. K.) 07. geol. Soc. Aust. 7, 263-8.

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DAWD, T. W. E. I95O (see Item 65). JoNF.s, O. A. I948. Ore genesis of Queensland. Proc. roy. Soc. Qd, 59, 1-9I. D. B. Smith

(x76) Wh;,, sill Permian/M. Carboniferous (I) Rookhope borehole, County Durham, England (2) Outcrop at Housesteads, County Durham

Radiometric age K-Ar ('~B = 4"72 × IO-l°year-X; ire -~ 0"584 × IO-x°year-a; no further data given)

Depth (ft) K20 (%) Age (m.y.) Whole rock 305 0"56 3o5b+20 & 3oob+2 O Little Whin sill 305½ O-6O 267b+I8 f 746l} X'94 223b+15 768 I'85 197b+13 Great Whin sill 77 x 1"59 28ob+t8 827t X'54 I3ob-+-9 Outcrop at Housesteads -- x'I3 256b+I4

Age (=average of five results from the four least altered samples) : 28Ibm.y. (Miller & Mussett I963; see radiometric comment).

Stratigraphical age. The Wl~n sill cuts Carboniferous strata up to Middle Coal Measures in age, and pebbles of it are found in the Permian Upper Brockram.

Rgference$ DumtAM, K. C. et al. x96I (see Item 9I). HOLMES, A. & HARWOOD, H. F. x928. The age and composition of the Whin sill and the related dikes of the north of England. Miner. Mag. 2x, 493-542. MILLER, J. A. & MUSS~TT, A. E. 1963. Dating basic rocks by the potassium-argon method: the Whin sill. Geophys. 07. 7, 547-53- [E. H. Francis]

Radiometric comment. A petrographic re-examination of the original samples confirms that all the rocks have been subjected to a post-crystallization metasomatism of variable intensity; and as a result, the K-Ar ages are all discrepant. The presence of zeoliteslwhich may have captured excess radiogenic argon during the period of metasomatic redistribution (Miller & Fitch 1964) _ suggests that the ages may not all be discrepantly low. However, we consider the best estimate of the initial age to be the average of the three highest (295 ± I9m.y-), rather than the figure of 28xm.y. originally given (Miller & Mussett I963). F. J. Fitch & J. A. Miller

Reference MILLER, J. A. & FITCH, F.J. 1964. The age of the paroxysmal Variscan orogeny in England. Quart. 07. geol. Soc. Lond. x2o s [this volume], 159--73.

(t77) Sandrlngham Sands L. Cretaceous/L. Cretaceous West Dereham, Norfolk, England. 372 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometrff age K-Ar (hB = 4"72 x IO-a°year-1; he = 0"584 x xo-~°year-1) Glauconite s 8oo8: 4°Ar*/4°K = [o.oo794] , age: x3t q- 4m.y. For full analytical details see p. 148.

Stratigraphical age. Ryazanian, with Hectoroceras, I ft above remani4 bed at base of Cretaceous (see p. i47 ). [M. H. Dodson] Reference DODSON, M. H., REx, D. C., Cas~Y, R. & ALLEN, P. x964. Glauconite dates from the Upper Jurassic and Lower Cretaceous. Quart. 07. geol. Soc. Lond. x2a s [this volume], i45-58.

Radiometric comment. Probably a minimum age, to be considered together with other ages from this and neighbouring stratigraphical horizons (Items x78--8o, 232-42 ). M. H. Dodson

(178) Sandringham Sands U. Jurassic/U. Jurassic West Dereham, Norfolk, England.

Radiometric age K-Ar (hB = 4"72 x Io-l°year-1; he = 0"584 × Io-l°year-X) Glauconite s 8005: 4°Ar*/4°K = [o'oo797], age: I32 + 4m.y.

Stratigraphical age. Lower Volgian, with Paracraspedites, 5 to 6 ft below base of Cretaceous. [M. H. DodsSon]

Reference and radiometric comment. See Item t 77. M. H. Dodson

(x79) Pond Sand U. Jurassic/U. Jurassic Kingsclere borehole, Hampshire, England.

Radiometric age K-Ar (hp = 4"72 × xo-l°year-X; he = 0"584 × IO-t°year -I)

4°Ar*#°K Age (m.y.) [0"00784] ] . ('[I3O ] Olauconite s 8oo4: [o oo774] ff ,29±3 ~. [x281

Stratigraphical age. Lower Volgian, ? gorei zone 63 ft above base of Portland Sand. [M. H. Dodson]

Reference and radiometric comment. See Item 177. M. H. Dodson

(It/o) Portltmd Sand U. Jurassic/U. Jurassic Wheatley, Oxfordshire, England.

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Radiometric age K-At (~p = 4"72 × Io-X°year-a; ~ = 0'584 × Io-l°year -1) 4°Ar*/4°K Age (m.y.) f[o'oo77x]'~ f[I27] Glauconite s 8oo3: ~. [o.oo788 ] ? I994-3l [i3o ]

Stratigraphical age. Lower Volgian, gorei zone. xft above basal Upper Lydite Bed. [1VL H. DodsonJ

Reference and radiometric comment. See Item 177. M.H. Dodson

(×el) Sedimentary rocks Cretaceous/Cretaceous Daghestan region, Caucasus, U.S.S.R.

Radiometric age K-Ar (constants not given) K (%) 4°Ar* (mmS]g × Io) 4°Ar*/4°K Age (m.y.) Glauconite (I) Kasumkent 4"67 I. 3 [o.oo4o8 ] 7° [68-5] (9) Zubutl 4"77 1.5 [o.oo46I ] 80 [77"5] (3) Vanashi-Makhi 6. x4 9"4 [o-oo573] 95 [95" 5] (4) Kasumkent 5.31 9.9 [0.00607] IOO [IOI]

Stratigraphical age. (I), Senonian; (9), Lower Albian; (3, 4), Lower Aptian.

Reference AUIRm~NOV, K. I., MAGATAZV, K. S. & TIMOX~EVA, G. I. I958. [Results of studies on the absolute age of sedimentary rocks of the oil-bearing province of Daghestan.] Trudi Sessii Komissii po Oprededen~yu Absolutnogo Vozrasta Geologicheskikh Formatsii, 5, 69-76. [In Russian]. [R. Casey]

(x82) Sylvine L. Cambrian/L. Cambrian Polovininsk Well, Irkutsk basin, U.S.S.R. (Usolsk suite)

Radiometric age K-Ar (4#-----4"9 × IO-x°year-1; he = 0"602 × IO-x°yeax -x) K = 5x .i%, 4°Ar = o'574 × Io-4cmS]g (2"5% arm. 4°At), 4°Ca* = 92"5ppm, 4°Ca*]total Ca = o.o 9. K-Ar age: 148 [I51J~] i Iom.y. K-Ca age: 62o [644:~] 4- 9om.y.

Stratigraphical age. Lena Stage, Lower Cambrian.

Rff fffetlce POLRVAVA, N. I. et al. I958 (see Item 53)- [M. H. Dodson]

Calculated by abstractor from authors' data using the constants adopted for this symposium. 374 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometric comment. The very low ratio of radiogenic to normal calcium in this sample means that the result should not be given too much weight. The authors' stated uncertainty appears rather optimistic. M. H. Dodson

Stratigraphical comment. The Usolsk suite from the Irkutsk Basin of Siberia is the lowest series of the Lena Stage and has been placed in the Lower Cambrian although it apparently is unfossiliferous: Likharev comments (1958 , p. 16o7) that 'cette s6rie n'est pas caract6risde au point de rue paldontologique'. The Lena Stage rests on the Aldan Stage, which is also Lower Cambrian: both stages have faunas including trilobites and archaeocyathids; the Usolsk suite is probably Lower Cambrian, but in the absence of fossils from the suite, this correlation depends on the field evidence.

Reference LIKHAREV, B. K. 1958. U.R.S.S. Lexique Stratigraphique International, II, fast. I-4. J. w. Cowie

(t$3) Murray Shale L. Cambrian/L. Cambrian Blount County, Tennessee, U.S.A.

Radiometric age Rb-Sr (X = I "39 × IO-11Year-a)

Rb STRb Sr s~Sr* Age (m.y.) (ppm) (ppm) (ppm) (ppm) s~Sr*/STRb ~t --= I "39 )~= I "47 Glauconite OL-20 (x) I89 53"5 20"7 0"44 [o.00822] 5864-15o [557] o'35 [o'oo723] 5154- I25 [49o] (2) 171 48. 4 28.4 o. 39;~ [o" 00806] 584 [577] 4- 3 ° [546] ++ Determined by much more accurate methods than the other two values.

Age: 584 [577] 4- 3 ° m.y. (2 = 1"39); [546]m.y. (,~ = 1"47).

Stratigraphical age. Lower Cambrian

References CORMIER, R. F. I957. (see Item I3). HOLMES, A. 1959. HURLEY, P. M. et al. I957. Variations in isotopic abundances of strontium, calcium and argon and related topics. Department of Geology and Geophysics, Massachusetts Institute of Technology, Fourth Annual Progress Report for I956-57 , pp. 2-23.

-- et al. I958 (see Item 7I). [J. W. Cowie]

Stratigraphical comment. The lower part of the Murray Shale, about 2o to 6oft above the base, yields the ostracod Indiana tennesseensis (Resser), which is known from Lower Cambrian strata in eastern and western North America and in western Europe. Q uartzites and shales lying below the Murray Shale are unfossiliferous; the sample may therefore be of early Lower Cambrian age.

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Items Reference PAI.Um% A. R. & LAUI~NCa~, R. A. I963. Age of the Murray shale and Hesse Quartzite on Chilhowee Mountain, Blount County, Tennessee. Prof. Pap. U.S. geol. Surv. 475-c, Article '7 3, c 53-4. J. W. Cowie

(x84) Pre-Sturtlan granite, Adelaide system late Pre-Cambrian/late Pre-Cambrian Crocker's Well area, Olary District, Australia.

Radiometric age 238U-~°6Pb: 52o a 4- Iom.y. ~36U-20~pb: 6oo a 4- 4om.y. 232Th-~°sPb: 585 a 4- 4om.y.

Stratigraphical age. Late Pre-Cambrian.

Reference CAMPANA,B., I95 4. Absolute age of uraniferous granite and Pre-Cambrian tillite in the Crocker's Well area (Olary District). Aust. 07. Sci. x6, 24o-I. [J. W. Cowie]

Radiometric comment. The uranium deposit at Crocker's Well lies within the general region of the later Proterozoic Adelaide System, but is part of an extensive area of Archaean porphyritic granitic rocks that crop out as prominent hills, overlain inconformably by Proterozolc glacial beds of the Adelaide System. The uranium mineralization is mainly thorian brannerite ('absite'). Greenhalgh & Jeffery (i959) noted that radon loss was indicated but leaching of uranium also occurred, and they quoted Kulp's estimate of 58o ± 3om.y. as the 'best' age. Wetherill (196o) criticized these results and stated that the apparent ages are scarcely suitable for fixing a critical point in the geological column. Holmes (I 96o) supported Greenhalgh & Jeffery to some extent but considered the interpretation of these inconclusive data to be of minor significance compared with newer age-determinations then available. Davidson (I96O), reporting on his visit to the Australian occurrence, stated that the brannerite occurrences are not actually overlain by Pre- Cambrian sediments of the Adelaide System, and the samples had not been suitably collected.

References DAVIDSON, C. F. 196o. Age of the Cambrian System. Nature, Lond. x87, IO2O-I. GREENHALGH, D. & JEFFERY, P. M. I959. A contribution to the Pre-Cambrian chronology of Australia. Geochim. et cosmoch. Acta, 16, 39-57- HOLMES, A. I96O. [Reply to Wetherill (I96O)] Nature, Lond. x87, 35-36. WETHERILL, G. W. I96o. Age of the base of the Cambrian. Nature, Lond. x87, 34-35- J. W. Cowie

Stratigraphical comment. Davidson (196o) suggested that the brannerite mineralization is completely lacking in stratigraphical definition and contributes no information about Cambrian chronology. Even if this comment is not entirely accepted, it seems most probable that the sample pre-dates the Sturt Tillite, which is almost certainly of late Pre-Cambrian age, and the determination therefore contributes nothing to the solution of the problem of the age of the base of Cambrian. J. W. Cowie

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Items

(185) Kessyusse Beds of Aldan Series L. Cambrian/L. Cambrian Olenek Highlands, source of river Olenek, Siberia, U.S.S.R. Lower part of Kessyusse Beds.

Radiometric age K-Ar (~p = 4"72 × lO-l°year-X; he = 0"557 × lO-l°year -1) Glauconite: K = 4-4o%, 4°Ar*/4°K = 0-0355, age: 55 ° [527]m.y.

Stratigraphical age. Lower Cambrian.

Reference POLF.VAVA, N. I. & KAZAKOV, G. A. I961 (see Item IOO). [J. w. Cowie]

Stratigraphical comment. The Kessyusse Beds contain olenellid trilobites with Hyolithes and rest unconformably on the Turkutsk Series, which has been dated at 675m.y. J. W. Cowie

(x86) Granite, Wichita Mountains U. Cambrian]Pre- Cambrian Wichita Mountains, Oklahoma, U.S.A.

Radiometric age (I) K-Ar ('~B = 4"72 × Io-l°year-1; ;re = o'585 × 1o-t°year-1; 4°K/K = 1.22 × lo-4g/gK) Biotite: ~°K ----- 4"86 ppm, 4°At* = o. 148 ppm, 4°Ar*/4°Ar t°t = o.8I, 4°Ar*/4°K = [o-o3o5], age: 46o m.y. (2) Rb-Sr (;t = 1 "39 × Io-nyeax-1; SVRb]Rb = o'283 g/gRb) Biotite: S7Rb = 249 ppm, sVSr* = I "77 ppm, SvSr*/totalSTSr = o.5o, sTSr*/SVRb = [o'oo7Io], age: 5Iom.y. (~ = 1.39); [48I]m.y(;t = 1.47 ). (Aldrich et al. 1958) (3) Th-Pb ()~2s~ = 4"99 × Io-lXY ear-t) U-Pb ('~235 = 9"72 X Io-t°year-1; 2asU/U = 0"00711 g/gU) (~3s = I "54 × Io-l°year-1; 32sU/U = 0"9929 g/gU) Wichita Mountains pegmatite Zircon U Th Pb 2°sPb At. ~o relative to 2°6Pb (ppm) (ppm) (ppm) (ppm) 2°4Pb 2°epb 2°Tpb 2°sPb (i) 20624-20 812o+8o 376 t56"o4-2"3 o.2954-o.oo6 ioo lO. io4-o, io 1.294-O-Ol (ii) 4144-4 I337+ 13 63"5 3o.74-I.o o.i21±o.oo 3 ioo 7"584-0"08 1"o34-o"oi

Age (m.y.) ~ssU/~°ePb 235U/207pb 207pb/206pb 23*Th/208pb (i) 520"4- I2 527a4- IO 55oa+3 o 506a+ I2 (ii) 514a-J- I2 522a4 - 10 55oa+ 20 493a+ 12

Ages considered concordant (agree within lO%) Mean zircon age: 523 [+ 7]m.y. (Tilton et al. 1957) Stratigraphical age. Upper Cambrian.

Rfferences ALDRICH, L. T. et al. 1958. Radioactive ages of micas from granitic rocks by Rb-Sr and K-A methods. Trans. Amer. geophys. Un. 39, 1124-34.

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Items

DAvxs, G. L. et al. I957. The ages of rocks and minerals. Rep. Carneg. Instn. 195tV-7, 164-71. HAMILTON, W. B. I956. Precambrian rocks of Wichita and Arbuckle Mountains, Oklahoma. Bull. geol. Soc. Amer. 67, 13 i9-33 o. TILTON, G. R., DAVIS, G. L., WETH~RILL, G. W. & ALDRICH, L. T. 1957. Isotopic ages of zircon from granites and pegmatites. Trans. Amer. geophys. Un. 38, 36o-71 . [J. W. Cowie & A. G. Smith]

Stratigraphical comment. The granite is unconformably overlain by Upper Cambrian strata, which suggests only that the Upper Cambrian is younger than 55om.y. J. W. Cowie

(z87) Utica shales Ordovician/Ordovician L'Epiphanie, Quebec, Canada [45 ° 5o'N, 73 ° 3o'w].

Radiometric age (1) K-At (constants not given) Biotite B4055: K = 3-69%, air corm ----- I9% , 4°Ar*/4°K ----- 0-0262, age: 402 + 25m.y. (2) Rb-Sr (constants not given) Biotite: Rb = I47.8 ppm, Sr = I15.2 ppm, sTSr* = o'34, STSr*/STRb = [o.oo812], age: [58~]m.y. (2 ---- 1.39); 55 ° -4- 75m.y. (2 ~ 1.47 ).

Stratigraphical age. The biotite concentrate was obtained from basal Utica Shales that succeed Trenton Limestones in the Montreal lowlands. The precise allocation of the Utica Group within the standard succession of North America is not altogether certain (Dunbar 1954), although Berry (I96O) has followed the Canadian practice of assigning it to the Edenian Stage.

References BEALL, G. H. I962. Age of authigenic biotite in the Utica shale. Amer. Min. 47, 971-74. BERRY, W. B. N. 196o. Graptolite faunas of the Marathon region, West Texas. Publ. Univ. Tex. 6NmS, 1-I79. DUNBAR, C. O. et al. 1954. Correlation of the Ordovician formations of North America. Bull. geol. Soc. Amer. 65, 247-98. [A. Williams]

Radiometric comment. The Utica Shale biotite is supposed to be of authigenic origin but has given ages too young or too old compared with other determinations for rocks of this stratigraphical age. Beall (i 962) considers that some argon loss by diffusion may have taken place during the Mon- teregian (Lower Cretaceous) igneous period. He attributes the excessively high age to abnormal concentrations of strontium in shale detritus that was likely to have been of Grenville origin and made up 37% of the residue used for age-determination. A. Williams

(188) Metasedlments mad igneous rocks, kntarctlea ? Ordovician/Cambrian Taylor Valley, Victoria Land [77 ° 4o's, 163°E].

Radiometric age K-Ar (no data given) 378 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Biotite Age (m.y.) (x) From metasediments 5oo a4- 20 (2) From lamprophyric dyke 458a4-2o (3) From monzonitic gneiss 425a+2o

Stratigraphical age. Late Cambrian--early Ordovician (?).

Rgfg[elq~e ANGXNO, E. E., TUm~ER, M. D. & Z~LL~R, E.J. 1962. Reconnaissance geology of Lower Taylor Valley, Victoria Land, Antarctica. Bull. geol. Soc. Amer. 73, I553-62. [A. Williams]

Stratigraphical comment. Biotite samples, separated from marbles of a metamorphosed suite of sediments in sharp contact with banded granites, suggest a late Cambrian-early Ordovician orogeny and a correlation of the marbles with Cambrian limestones with Archaeocyathus farther south. The intrusion of at least three suites of lamprophyre dykes appears to have occurred significantly later, but the age discrepancy for the monzonitic gneiss may be due to metamorphic effects. A. Williams

(*89) Martlnsburg Shale Ordovician/Ordovician Fisher's Hill, Virginia, U.S.A. [39°N, 780 6'W].

Radiometric age Pb--a: zircon in bentonite; age: 343am.y.

Stratigraphical age. The sample analysed was taken from a bentonite bed in the basal succession of the Martinsburg Shale and 7 ft above the top of the Oranda Formation (formerly part of the Chambersburg Limestone--see Cooper [i 956]). The horizon is correlated with the basal Trenton Series.

References CARROLL, D. 1959. Zircon from a bentonite bed in Martinsburg shale (Ordovician) at Fisher's Hill, Virginia. Bull. geol. Soc. Amer. 7o, 223-4. COOPER, G. A. I956 (see Item 156). [A. Williams]

Radiometric comment. The lead-a (Larsen) method of determining the age of a mineral is described in Larsen, Keevil & Harrison (1952) and evaluated in Gottfried, Jaffe & Senftle (i959). Gottfried, Jaffe & Senftle stress that the method is much less precise than any of the isotopic methods (K-Ar, Rb-Sr, U-Pb, and Th-Pb) and that several determinations are essential in order to evaluate results: a single age may provide only a crude approximation to the true age of a mineral. From an extensive survey of many lead-a ages, Gottfried, Jaffe & Senftle find an average standard deviation of IO% or less for Phanerozoic rocks older than the Cretaceous, and more than Io% for younger rocks. The most reliable lead-a age in this symposium is thus given by data from the Idaho batholith (Item 33o), and for the purposes of constructing a time-scale the other ages (Items I3i-4, I89, 217, 33o-i) are ofquestlonable value. 379 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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References GOTTFRIED, D., JAFFE, H. W. & SENFTLE, F. E. I959. Evaluation of the lead-alpha method for determining ages of igneous rocks. Bull. U.S. geol. Surv. xo97-A. LARS~N, E. S., K~Fvxr., N. B. & HARRISON, H. C. I952. Method for determining the age of igneous rocks using the accessory minerals. Bull. geol. Soc. Amer. 63, xo45-52. A. G. Smith

(x9o) Red Hill dyke, Tasmania L. Tertiary/M. Triassic Locality given as '20 m south-west of Hobart, Tasmania', member of an extensive suite of dolerite intrusions.

Radiometric age K-Ar (2B = 4"72 × IO-l°year-1; 2e = o'584 × IO-a°year-x) Minerals separated from fayallte-granophyre differentiate (except KA 8 xO).

Average KaO (%) 4°Ar*/4°K Age (m.y.) Whole-rock (chilled dolerite) KA 81 o o" 7485 o" 009007 148" 2 Sanidine KA8XI 7.O75 O'OO8692 I43"2 KA8IIR 7"O75 O'OO8771 144"5 KA833 6"7 x O'OO9569 I57"O KA833R 6"7X O'OO95O8 I56"X Plagioclase g.A812 0.573 O.OXOI8X X66"7 KA 812R 0"573 O'OIO239 I67"6 KA834 O'522 O'OO9774 I60"3 KA834R O'522 O'OO968O I58"8 Pyroxene KA8I 3 O'24I O'OO988I I62"O KA835 O'7485 O'OO1O17 I66"5

Age: 167 m.y. (McDougall 1961 )

Stratigraphical age. The tholeiitic Tasmanian dolerites intrude essentially flat-lylng Permian and Triassic sediments. The youngest sediments intruded are considered to be Middle or possibly Upper Triassic in age. Lower Tertiary fresh-water sediments overlie dolerite of this suite in northern Tasmania. Structural and petrographical analogy with the Karroo dolerites of South Africa suggests that the Tasmanian dolerites were intruded within the Jurassic or Lower Cretaceous periods (Banks I958 , pp. 234, 25Ia).

References BANKS, M. R. x958. A comparison of Jurassic and Tertiary trends in Tasmania. In Dolerite; A Symposium. Hobart (Geological Department, University of Tasmania), pp. 23x-64. McDotroAU, I. I96I. Determination of the age of a basic igneous intrusion by the potassium- argon method. Nature, Lond. x9o , 1 I84-6. [F. J. Fitch] 380 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Stratigraphical comment. This age is almost certainly post-Triassic, but not more than (?) possibly Jurassic.

Radiometric comment. Considerable care was taken by McDougall (I 96 I) to assess the various possibilities of error due to argon loss, and the age adopted is acceptable. F.J. Fitch & J. A. Miller

(i9i) I-llllhouse basalt sill -/Carboniferous Sill exposed in upper part of Hillhouse lime quarry, 1½ miles south of Linlithgow, West Lothian, Scotland [55 ° 57' 3 o''N, 3 ° 35' 4o"w] •

Radiometric age K-Ar (hB ----- 4"72 × Io-l°year-1; he = 0"584 × Io-l°year-x) K~O ----- i .23% , 4°Ar* = o.o1427 mmZ/g, a°Ar*#°K = [o-o2o49], age: 322 4- I2m.y.

Stratigraphical age. Sill intruded into the Lower Limestone Group of the Scottish Carboniferous succession. Basalts of Hillhouse type are almost entirely confined to the Bathgate Hills of West Lothian and Fife. Stratigraphically they range from the upper part of the Oil Shale Group to the middle part of the Upper Limestone Group (MacGregor & MacGregor 1948 ).

References MACGREOOR, M. & MACGREGOR, A. G. 1948. The Midland Valley of Scodand. Brit. reg. Geol. MILLER, J. A. & BROWN, P. E. Potassium-argon age studies in Scotland. Geol. Mag. [in the press]. [F. J. Fitch & J. A. Miller]

Stratigraphical comment. This sill cannot be older than the Lower Limestone Group rocks into which it is intruded. Lavas of Hillhouse-type basalt can be found within the Lower Limestone Group in the vicinity of Hillhouse quarry (W. Tulloch, personal communication), and the sill may well be of Lower Limestone Group age. Hillhouse-type basaltic volcanism does not appear to have continued into Scottish 'Millstone Grit Series' times in the Edinburgh district, and it is therefore virtually certain that the sill is of Scottish 'Carboniferous Limestone Series' age (i.e., Lower Namurian). F.J. Fitch & J. A. Miller

(x92) Essexlte porphyrlte ? L. Permian/? L. Permian Sande, Vestfold, Norway, 37 km south-west of Oslo [59 ° 35'N, 10 ° 12'~].

Radiometric age K-Ar (hp = 4"72 X IO-l°year-X; he = o'583 × Io-l°year-1) Biotite: no further analytical details given. Age: = 284bm.y.

Stratigraphical age. Lower Permian (?).

Reference NEUWANN, H. I96o. Apparent ages of Norwegian minerals and rocks. Norsk geol. Tidsskr. 4 o, 173-9 x. [D. B. Smith]

Stratigraphical comment. No stratigraphical details of the essexite dated were given in the original reference (Neumann 196o), but personal correspondence with the author shows that the rock is a basaltic lava belonging to the widespread multiple basal (B. I) flow of the Vestfold district. It 381 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems rests upon sedimentary rocks which at Semsvik (3 ° km north-north-east of Sande) have yielded fossils that Dix & Trueman (I935) and Hoeg (1935) considered to be early Permian (see also comments on Items 45 and 46). At Holmestrand (13 km south-south-east of Sande) B. 1 lavas are also overlain by fossiliferous early Permian sediments, indicating approximate contemporaneity of the lavas and sediments.

References DIx, E. & TRUEMAN, A. E. I935 (see Item 45). HoEc, O. A. I935. The Lower Permian flora of the Oslo region..ACorsk geol. Tidsskr. I6, 1-43. OFaXDAHL, C. I96O. Permian rocks and structures of the Oslo region. In Geology of )¢'orway. (ed. HOLaXDAHL, O.) Oslo, pp. 298-343. D. B. Smith

Radiometric comment. H. Neumann states that 'there is hardly any doubt that the biotite ... is formed by a later contact metamorphism of the essexite lava itself by the near-by larvikite' (personal communication). If this observation is correct, the lava would necessarily be appreci- ably older than 284m.y., an age that would be difficult to reconcile with the biostratigraphical age of the associated sedimentary rocks. D. B. Smith

(x93) Exeter Volcanic Series Triassic/Carboniferous (t) Killerton Park Lava and (2) Dunchideock Lava; Killerton Park, 5½ miles north-north-east of Exeter [5 o° 47'N, 3 ° 27'W] ; Dunchideock, 5 miles south-west of Exeter, Devon, England.

Radiometric age K-Ar (2# = 4"72 × IO-a°year-1; 2e = 0"584 × IO-x°year-z)

K~O (%) 'OAr (mm3/g) atmAOAr (%) '°Ar*/¢°K Age (m.y.) (I) Biotite 1/13 7"99 0"0800 2"4 [o"o172] 274 +Io H/37 8- I8 O'O818 I -~ [o"oi74] ~77 4- IO H/35 8"28 0"0877 2"6 [O"O182] 287 4-II H/36 8"28 O'OI51 O- 9 -- 276bztz8

(First three samples measured by total volume method; fourth by isotope dilution) Age: 279 4- 6m.y. (Miller, Shibata & Munro I962 ) (2) No experimental data available. Average from four analyses: 28i b 4- x i m.y. (Fitch & Miller I964)

Stratigraphical age. Regarded as Lower Permian, but direct stratigraphical evidence establishes only post-Namurian, and perhaps pre-Triassic age.

References FITCH, F.J. & MILLER, J. A. 1964 . The age of the paroxysmal Variscan orogeny in England. Quart. 07. geol. Soc. Lond. 12o s [this volume], 159-73. MILLER, J. A., SHIBATA,K. & MUNRO, M. 1962. The potassium-argon age of the lava at Killerton Park, near Exeter. Geophys. 07. 6, 394-6. [D. B. Smith]

Stratigraphical comment. The Killerton Park and Dunchideock lavas belong to the Exeter Volcanic Series (Dewey 1948, pp. 42-3), the distribution of which was described by Tidmarsh (I932, 382 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns pl. L). The volcanic rocks occur mostly at the base of the flat-lying New Red Sandstone outcrop, 9verlying with marked angular unconformity closely folded Upper Carboniferous strata of Namu- rian age (Butcher & Hodson i96o , pp. 78-9). These post-orogenic volcanic rocks represent the last phase in 'the Dartmoor cycle of igneous activity' (Tidmarsh 1932, p. 712; see Butcher 1961).

References BUTCHER, N. E. 196i. Age of the orogeny and granites in south-west England. Nature, Lond. 19o, 253, 486-7. & HODSON, F. 196o. A review of the Carboniferous goniatite zones in Devon and Cornwall. Palaeontology, Lond. 3, 75 --8I. DEWEY, H. 1948. South-west England. Brit. Reg. Geol. TtDm~RSH, W. G. I932. The Permian lavas of Devon. Quart. ,;7. geol. Soc. Lond. 88, 712-73 . N. E. Butcher

(x94) Tavarl group of intrusions U. Cretaceous/U. Cretaceous Western Georgia, U.S.S.R.

Radiometric age K-Ar (no constants given) Phonolite (whole-rock): K=4.39%, 40Ar* =o.oi 7 ramS]g, 40Ar*/4°K=o.oo57, age: 91 [95] m.y.

Stratigraphical age. Upper Cretaceous (Turonian).

Reference RUBINSHTmN, M. M. I958. [New data on the absolute age of magmatic occurrences in Georgia.] Trudi Sessii Ifomissii po Oprededen#u Absolyutnogo Vozrasta Geologicheskikh Formatsii, 9, 32o-9 [in Russian]. [R. Casey]

(195) Glauconltic sandstone, Georgia U. Cretaceous/U. Cretaceous Kutais region, Georgia, U.S.S.R.

Radiometric age K-Ar (no constants given)

4OAr, Glauconite K (%) (mm3/g) 4°AF*/4°K Age (m.y.) 4" 71 o" ot 5 o-oo47 76 [79] 4" 71 o- o 13 o" oo 41 66 [69] 4.71 0.023 0.0073 I I6 [I2I]

Stratigraphical age. Upper Cretaceous (Cenomanian). RejC~e//~e RUBINSHTEIN, M. M. 1958 (see Item I94 ) [R. Casey] 383 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(x96) Holyhead basic dyke Devonian/Silurian Holy Island, Anglesey, North Wales [SH 238808].

Radiometric age K-Ar ()lp = 4"72 × m-X°year-1; 2e = 0"584 X Io-l°year -1)

atm. K20 (%) 'OAr (%) '°Ar*(mmS/g) '°Ar*#°K Age (m.y.) 322 qHM 0"55 3"0 0"00827 [0"0266] 4074-22 322 5/Q o'55 O'4 O'OO845 [O'O27X] 4154-33 Age: 41o 4- i8m.y. (Fitch, Miller & Meneisy x963)

Stratigraphical age. The only direct evidence for the age of the dyke is that it intrudes the Pre- Cambrian Mona complex of Anglesey. Elsewhere in North Wales similar intrusions are contemporaneous with the development of major folds known to have formed in the early Silurian- mid-O.R.S, interval (Williams [i927] ; Shackleton [x959] ; Ramsay [I959] ; and Beavon [I963] ). By inference, the Holyhead dyke was intruded at some time within the same interval.

References Br~AvoN. R. V. 1963. The succession and structure east of the Glaslyn River, North Wales. Quart. 07. geol. Soc. Lond. xx9, 479-5xo. FITCh, F. J., MILLF.R, J. A. & M_~N~lSV, M. Y. I963. Geochronological investigations on rocks from North Wales. Nature, Lond. x~, 449-5 i. RaMSA'Z, J. G. i959. Itinerary II. Cwm Idwal-Capel Curig. In Williams, D. & Ramsay, J. G. Geology of some classic British areas: Snowdonia. Geol. Ass. Guide, 28, 9-I4. SHACKrFTON, R. M. I959. The stratigraphy of the Moel Hebog district between Snowdon and Tremadoc. Lpool Manchr geol. 07. % 2i6-52. WILLIAMS, H. I927. The geology of Snowdon (North Wales). Quart. 07. geol. Soc. Lond. 83, 346-427 . [F. J. Fitch & J. A. Miller]

(197) Claystone Oligocene/Oligocene About 75 ft above base of John Day Formation, central Oregon, U.S.A.

Radiometric age K-Ar (/tp = 4-72 × io-10year-S; 2e-~ 0"585 × Io-l°year-1) Authigenic adularia: r,~646: K ---- I 1.8%, arm. 4°At = 3I%, age: 2I-6bm.y. The dating of the adularia yields the time of replacement of plagioclase by pseudomorphic adularia, not the time of deposition of the tuffbed (Evernden et al. I964, p. x8o).

Stratigraphical age. Whitneyan-Orellan (Evernden et al. 1964, p. I8O).

R~gel/ce EVERND~N, J. F. et al. I964 (see Item 27). [B. M. Funnel1/

(x~II) Granodlorlte, Jamaica Tertiary/U. Cretaceous (i) Hall Green, Jamaica Ix8 ° ix'n, 760 5o'w]; (2) Troja, Jamaica [i8 ° I5'N , 760 56'w]; (3-5) Zion Hill Bridge [i8 ° IO'N, 760 54'W]. 384 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

Radiometric age K-Ar (;tD = 4"72 × Io-X°year-X; ~e = 5"84 X Io-X°year-X)

4OAr* K (%) (ml/g x Io s) '°Ar*#°K Age (m.y.) Feldspar (I) Hall Green Io'24 2"24 [0"00321] 56 [54]4-5 (2) Troja 4"67 I"38 [o'oo433] 75 [73]4-5 Biotite (3) Zion Hill Bridge 6.81 I. 8o [o. oo388] 67 [65" 5] 4- 5

Rb-Sr (;t = 1 "39 × xo-ny ear-x) (4) Biotite (Zion Hill Bridge): Rb = 339"5 Pg/g, Sr = 22"3 pg/g, 87Sr* = 0"0834 pg/g, sTSr*/S~Rb = [o.ooo867], age: 64 4- 5m.y. (4 -~ x "39); [59]m.y. (4 = I "47).

U-Pb (2*ss = 1 "537 × Io-l°Year-l) (5) Sphene (Zion Hill Bridge): U----- i7i "3 Pg/g, Pb : I3"4I #g/g, lead composition: ~°4Pb = o'976%, ~°6Pb ---- 29"545%, 2°vpb = x5"574%, "°sPb = 53"9o5%, age: 64 a -4- 5m.y.

The Hall Green feldspar was collected from sheared granodiorite adjacent to a fault. All the biotite had been altered to chlorite and it probably lost radiogenic argon during low-grade metamorphism and faulting. The Troja feldspar is 'altered and unsuitable' for age-determination. The Zion Hill Bridge material was fresh and unaltered. Adopted age of Zion Hill Bridge granodiorite: 65 -4- 5m.y. Chubb & Burke (I963) Mean age: [63 q- 3] m.y. (using 4 ---- 1.47 for Rb-Sr).

Stratigraphical age. The youngest rocks intruded by the granodiorite are not older than Maestrich- tian, and the oldest overlying rocks are not younger than lower Middle Eocene. The granodiorite provides pebbles for the Wagwater Conglomerate, of Middle (? and Lower) Eocene age. Intrusion therefore took place during the latter part of the Maestrichtian, the Danian, the Palaeo- cene, the Lower Eocene, or the lowest Middle Eocene. Because of the time needed to unroof the granodiorite and deposit the Wagwater and associated strata, a very late Cretaceous age for the intrusions seems most likely (Chubb & Burke x963). [R. Casey]

Radiometric comment. There is excellent agreement among the ages obtained by different methods for the Zion Hill Bridge rocks. However, the K-Ar results of 73 m.y. is a minimum age and cannot be ignored. If, as the authors suggest, the Troja feldspar has been subjected to a post-intrusive low-grade regional metamorphism, then some of the Jamaican granodiorites crystallized before 73 m.y. and these intrusions may well be composite. A. G. Smith

Rg~re?/c8 CHUBS, L.J. & BURKE, Kevm. t963. Age of the Jamaican granodiorite. Geol. Mag. too, 524-32.

(x99) Pemblmt coal seam Palaeocene/U. Cretaceous Whitecourt, Alberta, Canada [54 ° O5'N, 115 ° 3 It W].

Radiometriv age K-Ar (4~ = 4"76 × ×o-×°year-X; 4e = 0'589 × Io-l°year-1; 4°K/K -~ o.oIx8 at. %) 385 O Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

Bentonite 4°K (ppm) l°Ar*#°K Age (m.y.) Biotite 3 "84 o'oo376 634-3 Sanidine i o- 74 o. oo386 64 [64" 5] 4- 3

Mean age: 63 [63"5-t- 2]m.y.

Stratigraphical age. Presumed topmost Cretaceous (Upper Maestrichtian).

Reference FOLINSBEE, R. E., BAAVSCAARD, H. & LIPSON,J. 196 r. Potassium-argon dates of Upper Cretaceous ash falls, Alberta, Canada. Ann..New Tork Acad. Sci. 9', 35~-59. [R. Casey]

Stratigraphical comment. Bentonites interbedded with the Pembina (or Ardley) coal seam are considered the latest datable Mesozoic beds in Alberta (Folinsbee, Baadsgaard & Lipson x96I, P. 354)- At Whitecourt this seam lies 2oo to 3oo ft above the Maestrichtian Kneehills tuff zone; in the Edmonton area a maximum of 4oo ft of strata intervene between the Kneehills tuff and the Tertiary. Folinsbee, Baadsgaard & Cumming (I963, p. 78) have described the Whitecourt bentonite in the Pembina coal seam as the 'stratigraphic equivalent' of the 'Big Dirty' coal seam of the basal Fort Union group of Montana, which has a similar radiometric age (62.7 m.y.). The Fort Union group is regarded as Palaeocene (Jeletzky 196o). The precise position of the Pembina coal seam in relation to the Mesozoic-Cainozoic boundary is therefore open to question.

Re, fences FOLINSBEE, R. E., BAADSO,~O,aD, H. & COMmNO, G. L. I963. Dating of volcanic ash beds (bentonites) by the K-Ar method. In Nuclear physics, pp. 7o-82. Nuclear Science Series Report 38. Washington (National Academy of Sciences National Research Council). JELEaXKY, J. A. x96o. Youngest marine rocks in western interior of North America and the age of the Triceratops-beds; with remarks on comparable dinosaur-bearing beds outside North America. Int. geol. Congr. ux (5), 25-4o. R. Casey

(200) Kneehills tuffzone U. Cretaceous]U. Cretaceous Strawberry Creek, Alberta, Canada [53 ° X6'N, I X4° O7'W].

Radiometric age K-Ar (2B = 4"76 × xo-l°year-a; ~e = 0"589 × xo-X°year-a; *°K/K = o.oxx8 at. %)

Bentonite 4°K (ppm) 4°Ar*/4°K Age (m.y.) Biotite (altering to vermiculite) o- 46 o. 0039 x 65 4- 3

Sanidine 7" 79 o. oo396 66 + 3 Sanidine 8.5 ° o. oo396 66 4- 3 Sanidine 9" 63 o. oo4o8 68 4- 3 Sanidine I. 32 o. oo393 66 [65 • 5] 4- 3

Mean sanidine age: 66.5 m.y. Mean of all ages 66 [+ o.5]m.y.

Stratigraphical age. Upper Cretaceous (late Maestrichtian) 386 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items Rff6q-6~/7,ce FOLINSBE~, R. E. BAADSOAARD, H. & LXPSON, J. 1961 (see Item 199 ). R. Casey

Stratigraphical comment. The Kneehills tuff zone of the upper Edmonton or Battle Formation is a widespread zone of volcanic ash characteristically associated with a bentonitie clay bed. It marks the transition to Lance Beds and the introduction of the dinosaurs Tricerato#s, Tyrannosaurus, Anklosaurus, and Thecalosaurus; it is thus an excellent marker-bed. Jeletzky (196% 1962 ) has shown that this horizon is high in the Maestrichtian, and is not Danian as previously supposed.

References JPLETZKY, J. A. 1960 (see Item 199). I962. The allegedly Danian dinosaur-bearing rocks of the globe and the problem of the Mesozoic-Cenozoic boundary. 07. Paleont. 36, IOO5-I8. R. Casey

(2ox) Bearpaw Shale (bentonite no. x) U. Cretaceous/U. Cretaceous Lethbridge, Alberta, Canada [49 ° 42'N, I I2 ° 531W].

Radiometric age (gB = 4"76 × I°-X°year-x; ge = o'589 × IO-l°year-1; 4°K/K = o.oii8 at. %)

Bentonite 4°K (ppm) 4°Ar*/4°K Age (m.y.) Biotite 6" o3 o. oo4o8 68 4- 3 o. 00464 77 + 4 7" 05 o. OO4A,A , 74 4- 4 Sanidine 5" 48 O" OO457 76 4-4 IO" 56 O" OO462 774-4 Mean age: [74 4- i '5]m.y.

Stratigraphical age. Upper Cretaceous (Upper Campanian).

Reference FOLINSBV_a~, R. E., BAADSGAARD, H. & LIPSON, J. I96I (see Item i99 ).

Stratigraphical comment. The Bearpaw Shale is considered to span the interval Upper Campanian- Lower Maestrlchtian (Reeside 1957). Landes (in Russell & Landes I94o, pp. I86-7) records the Upper Campanian ammonite Acanthoscaphites nodosus above the Bearpaw no. t bentonite here dated.

References REESlDE, J. B. Jr. I957. Paleoecology of the Cretaceous seas of the western interior of the United States. In Treatise on marine ecology and palaeoecology, vol. 2, 505-40. Mem. geol. Soc. Amer. 67. RUSSELL, L. S. & LANDES, R. W. 194 o. Geology of the southern Alberta plains. Mere. geol. Sum. Can. aaz: 75. [R. Casey] 387 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(202) Crowsnest Vol_~n;cs U. Cretaceous/? L. Cretaceous Coleman and Mill Creek, Alberta, Canada. (i) [49 ° 39'N, I14 ° 3I'w]; (2) [49 ° 25'N, 114 ° O9'W]; (3) [?]. Radiometric age K-At (ha = 4.76 × lO-x°year-X; ~e = o'589 × Io-nyear-a; ~°K] K ----- o-olI8 at. %)

4°K (ppm) '°Ar*#°K Age (m.y.) (1) Bentonite, Coleman, Alberta I2"76 0"00567 944-5 Sanidine x3" o6 o. oo54o 9o 4- 5 Mean age: 92 [+ 3] m.y. (2) Bentonite, Mill Creek, Alberta Biotite 6.88 o. oo596 99 4- 5 Sanidine t o. 69 o. oo6o9 1o 1 4- 5

Mean age: lOO [4- 3]m.y. (Folinsbee, Baadsgaard & Lipson 196I )

(~B = 5"o3 × IO-x°year-X; R = o. 110; 4°K/K = o-oi I9 at. %) (3) Crowsnest Volcanics Feldspar: K = IO.82%, 4°Ar*#°K = o'oo54, age: 94"9 [9o] ± 4"7m.y. (Lipson I958 )

Stratigraphical age. Cretaceous (Albian or Cenomanian).

References FOLINSBEE, R. E., BAADSGMRD, H. • LIPSON J. i961 (see Item 199 ). LIPSON J. I958 (see Item I2). [R. Casey]

Stratigraphical comment. Folinsbee, Baadsgaard & Lipson (1961) assigned the Crowsnest Volcanics to the Cenomanian and quoted the occurrence of the Upper Cenomanian ammonite Dunvegano- ceras 15 ft above this horizon. Later (Folinsbee, Baadsgaard & Cumming I963, p. 76), an Albian age was preferred. Tentative correlation of the Crowsnest Volcanics with the Mowry Shale of Montana and Wyoming (Folinsbee, Baadsgaard & Cumming 1963, p. 73) is of little help, since although this shale is generally dated as late Albian an early Cenomanian age cannot be excluded (Reeside & Cobban 196o) (see Item 2o4. )

References FOLINSBEE, R. E., BAADSGAARD, H. & CUMMING, G. L. I963 (see Item 199 ). 1963 (see Item 199 ). REESlDE, J. B. Jr. & COBBAN, W. A. 196o. Studies of the Mowry shale (Cretaceous) and contemporary formations in the United States and Canada. Prof. Pap. U.S. geol. Surv. 355. R. Casey

Radiometric comment. The Coleman and Mill Creek bentonite beds appear to be of significantly different ages. A. G. Smith

(203) ttatmon Shale L. Cretaceous/L. Cretaceous Hudson Hope, British Columbia, Canada [560 O7'N, I2I o 48,W]" 388 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometric age K-At (2p = 4"76 × Io-l°year-a; ~ = o'589 × xo-l°year-a; 4°K/K = o.oII8 at. %) Tuff '°K (ppm) 'OAr*#OK Age (m.y.) Chloritized biotite 3" oo o. 00726 1194- 6 o'oo695 l ~54-6 Mean age: 117 [ 4- 4] m.y.

Stratigraphical age. Lower Cretaceous (Albian)

Reference FOLINSBEE, R. E., BAADSGAARD,H. & LIPSON,J. x96I (see Item I99 ). [R. Casey]

Stratigraphical comment. The ammonite Gastroplites occurs immediately above these dated biotites (Folinsbee, Baadsgaard & Cumming I963, p. 73). The only known occurrence of Gastroplites in a well-documented European succession is at Folkestone Kent (Casey 1936) ; here a single example was found in the cristatum Zone, formerly regarded as the top of the Middle Albian but now assigned to the base of the Upper Albian (Rat I963). The Middle Albian age-assignment given to these biotites by Folinsbee, Baadsgaard & Cumming (i963) may well be correct, though an earlier age is suggested by the radiometrie result.

References CAs~.Y, R. I936. Recent additions to the Albian ammonoid faunas of Folkestone. Geol. Mag. 73, 444--8. FOLINSBEE, R. E., BAADSGAARD,H. & CUMMING, C. L. z963 (see Item I99 ). RAT, P. I963 (see Item 75)- R. Casey

(2o4) Mowry Shale mad Frontier Forxnatlon M. Cretaceous/M. Cretaceous (I) Emigrant Gap anticline, Casper, Wyoming; (2) Winnecook Ranch, Wheatland County, Montana, U.S.A.

Radiometric age K-Ar (~p = 4-76 × to-t°year-X; he = 0"589 × Io-l°year-X; 4°K/K = o.oix8 at.%) Age (m.y.) Sanidine Biotite (x) Frontier Formation Bentonite IA 94 b 86b [ Bentonite I B (Clayspur) 94b 90b (I) Mowry Shale J Bentonite 2 935 9 °5 ] Bentonite 3 96b 96b [.Bentonite 4 97 b 94b (2) Mowry Shale Bentonite 95" 3 b ~ 96. ~b No laboratory data in source publication.

Stratigraphical age. Cretaceous (presumed Upper Albian).

Rff~Tenc6 FOLINSBEE, R. E., BAADSGAARD,H. & CUMMING, G. L. 1963 (see Item 199 ). JR. Casey] 389 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Stratigraphical comment. The authors accept the Clayspur Bentonite as the marker between the Albian and the Cenomanian (i.e., between Lower Cretaceous and Upper Cretaceous) and assume that the Mowry Shale belongs wholly to the Upper Albian. Correlation of the Mowry sequence with the standard European palaeontological succession is not yet possible and a Ceno- martian age for the whole or part of this sequence cannot be ruled out (Reeside & Cobban 196o). Combined with sanidine dates from the Emigrant Gap sequence of bentonites, these results are used by Folinsbee, Baadsgaard & Cumming (I963) to give a time-scale .for the Mowry Shale as follows: Neogastroplites maclearni Zone 94bm.y. .N'eogastroplites americanus Zone 96b m.y. Neogastroplites cornutus Zone 98b m.y. Areogastroplites is apparently endemic to the western interior of North America and is most likely of Upper Albian age. Rffcrg//ge R~sID~, J. B. Jr. & COBBAN, W. A. I96o (see Item 2o2). R. Casey

(205) Denton, Weno, and Del Rio formations U. Cretaceous/L. Cretaceous 'Outcrops, Texas', U.S.A.

Radiometric age K-Ar (2# = 4"72 X Io-X°year-1; ,~e = o'585 x Io-X°year-1) Illite from shales" --4/~ fractions Air K (%) '°Ar*/'°K corm (%) Age (m.y.) Denton 3-oo o.oIo 7 4 I I75 Weno 2" 38 o. o xo4 26 I7O Del Rio 2" 54 o. o i o9 34 I78 RejeTencg HURLEY, P. M. et aL I963 (see Item 48). [R. Casey]

Stratigraphical comment. The Denton and Weno formations are of Upper Albian (highest Lower Cretaceous) age; the Del Rio of early Cenomanian (lowest Upper Cretaceous) age (Adkins I928). The ages obtained are much higher than from igneous minerals in contemporary strata; the authors suggest the presence of older detrital components in the samples.

ADKINS, W. S. 1928. Handbook of Texas Cretaceous fossils. Bull. Univ. Texas 2838. R. Casey

Radiometric comment. See Item 48. A. G. Smith

(2o6) 'Datsky Stage' ? Palaeocene/? U. Cretaceous Ullu-Chay, Daghestan, U.S.S.R.

Radiometric age K-Ar (2B = 4"72 × Io-X°year-1; 2e = 0"557 x xo-X°year-a) Glauconite: K = 4" 62%, 4°Ar*/4°K = o'oo38, age: 7 ° [64] m.y. 39 ° Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical age. 'Cretaceous (Danian)'. R~re?/ge POLEVAVA, N. I., MUmNA, C. A. & KAZAKOV, G. A. I96i (see Item 20). JR. Casey]

Stratigraphical comment. The Danian stage is regarded by the abstractor as part of the Palaeocene. This result accords with a position at the Cretaceous-Palaeocene boundary. R. Casey

(2o7) Glauconlte in Senonian Sediments, Saratov U. Cretaceous/U. Cretaceous Lysaya Hill, Saratov, Volga River, U.S.S.R.

Radiometric age K-Ar (2# = 4'72 X Io-l°year-1; ;re = o'557 × IO-x°year-t) Glauconite: K = 6"o2%, 4°Ar*#°K -- o'oo45, age: 79 [75] m.y. [R. Casey]

Stratigraphical age. Upper Cretaceous (Senonian). Reference POta~VAW,, N. I., MUI~XNA, C. A. & KAZAKOV, G. A. x96I (see Item 2o). [R. Casey]

(2o8) Coniaclan sedlnaents U. Cretaceous/U. Cretaceous Lysaya Hill, Saratov, Volga River, U.S.S.R.

Radiometric age K-At (2p = 4"72 × 1o-l°year-a; 2e = 0"557 × Io-l°year -1) Glauconite: K = 5"96%, 4°Ar*/4°K = o'oo44, age: 78 [74]m.y.

Stratigraphical age. Upper Cretaceous (Coniacian).

Reference POLEVA~'A, N. I., MumNa, C. A. & KAZAKOV, G. A. I96I (see Item 2o). [R. Casey]

(209) Cenomanlan sandstone U. Cretaceous/U. Cretaceous Koberzhik borehole, Czechoslovakia.

Radiometric age K-At (2p = 4"72 × Io-a°year-X; ~ = o'557 x Io-l°year -1)

Glauconite extracted from sandstone K (%) 4°Ar*#°K Age (m.y.) Sample x (depth 76-7 m) 6- oo o. oo45 79 [75] Sample 2 (depth 77-8m) 4"42 o'oo53 93 [89] 39I Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical age. Upper Cretaceous (Cenomanian).

Reference POL~.VAYA, N. I., MURINA, C. A. & KAZAKOV, G. A. I96I (see Item 2o). [R. Casey]

Radiometric comment. Sample 2 gives a result consistent with that from igneous minerals elsewhere. The value obtained from Sample x is anomalous and far too low. R. Casey

(2xo) Koshatld deposit U. Cretaceous/U. Cretaceous Melnyk district, Czechoslovakia.

Radiometric age K-At (2p = 4"72 × Io-l°year-1; 3~ : 0"557 × Io-t°year -1) Glauconite: K : 5"78%, ~°Ar*/4°K : o'oo45, age: 8o [75]m.y.

Stratigraphical age. Upper Cretaceous (Cenomanian).

Reference POt2SVAYA, N. I., MURINA, C. A. & KAZAKOV, G. A. I96I (see Item 2o). [R. Casey]

(21I) Bukanskoye deposit U. Cretaceous/U. Cretaceous Kaluga district, U.S.S.R.

Radiometric age K-At (;tB = 4"72 × IO-t°year-1; he----o'557 × Io-l°year -x) Glauconite: K = 4"29%, 4°Ar*/4°K = o'oo57, age: I OO [95] m.y.

Stratigraphical age. Upper Cretaceous (Cenomanian).

Reference POL~VAYA, N. I., MURtNA, C. A. & I~ZAKOV, G. A. I96I (see Item 2o). [R. Casey]

(~12) Jklblall sediments L. Cretaceous/L. Cretaceous Skryleyeva Ravine, Great Laba River, northern Caucasus, U.S.S.R.

Radiometric age K-Ar (~p = 4"72 × xo-X°year-X; 2c = 0"557 × IO-x°year-l) Glauconite from aleurolite: K = 5" 72%, 4°Ar*/4°K ---- 0'0059, age: xo3 [98] m.y.

Stratigraphical age. Lower Cretaceous (Albian).

Reference POL~VAYA, N. I. MURINA, C. A. & KAZAKOV, G. A. I96I (see Item 2o). [R. Casey] 392 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(2x3) Aptl~n sediments L. Cretaceous/L. Cretaceous (r) Skryleyeva Ravine, Great Laba River; (2) Belaya River; (3) Baksan River, U.S.S.R.

Radiometric age K-Ar (2# = 4"72 X xo-X°year-a; ~ = 0"557 × IO-*°year-*) Glauconite K (%) 4°Ar*#°K Age (m.y.) (I) 6"35 o'oo53 93 [89] (2) 5-00 o'oo6x Io 7 [IO2] (3) 5" 68 o" oo53 93 [89]

Stratigraphical age. Lower Cretaceous (Aptian).

Reference POL~VAYA, N. I., MtmXNA, (3. A. & KAZa~KOV, G. A. x961 (see Item 2o). JR. Gasey]

(2x4) Barremian sediments L. Cretaceous/L. Cretaceous Inguri River, Georgia, U.S.S.R.

Radiometric age K-Ar (2# = 4"72 × IO-x°year-1; 2e = o'557 × xo-*°year-x) Glauconite: K = 5"28%, 4°Ar*/4°K = o'oo53, age: 93 [89]m.Y.

Stratigraphical age Lower Cretaceous (Barremian).

Reference Pot.evAva, N. I. MUmNA, C. A. & KAZAKOV, G. A. I96I (see Item 20). [R. Casey]

Radiometric comment. The age quoted is far too low for Barremian deposits. R. Casey

(215) 'Neokom' L. Cretaceous/U. Jurassic Lenin Hills, Moscow, U.S.S.R.

Radiomaric age K-Ar (2p = 4"72 × IO-x°year-l; 2e = 0"557 × Io-l°year-1) GIauconite: K = 5"23%, 4°Ar*/4°K = o'oo79, age: I36 [x3I]m.y.

Stratigraphical age. Lower Cretaceous (Neocomian). Reference POLEVAYA, N. I., MURINA, C. A. & KAZAKOV, G. A. I96X (see Item 2o). JR. Casey]

Stratigraphical comment. In the Lenin Hills the Neocomian consists of Barremian and remani6 Ryazanian (basal Cretaceous) deposits, and it rests on uppermost Jurassic (Volgian) ; the whole 393 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items sequence is rich in glauconite. The result agrees closely with the postulated date for the base of the Cretaceous but the sample may include reworked Jurassic glauconite. R. Casey

(2x6) Albian sediments L. Cretaceous/L. Cretaceous Socony Vacuum Oilsand well No. 27, MacMurray area, Alberta, Canada.

Radiometric age K-Ar (,~p = 5.03 × xo-X°year-t; R = o. 1 Io) Glauconite: K = 4.oi%, 4°Ar*/4°K = 0"00824, age: I42 [136 ] + Iom.y.

Stratigraphical age. Lower Cretaceous (Albian).

Reference LxPSON, J. I958 (see Item i2). [R. Casey]

Radiometric comment. This value is much too high. Lipson suggests that it may be due to contamination by older material embedded in the glauconite. R. Casey

(~x7) Granodlorlte U. Cretaceous]L. Cretacous La Grulla, northern Baja California, Mexico.

Radiometric age U-Pb: monazite: concordant age: i I5am.y. (Silver, Stehli & Allen i963). Pb-~: monazite: age: 99am.y. (Jaffe et al. I959).

Stratigraphical age. Cretaceous ('Albian').

Rffer6,~e$ JAFFa., H. W., Gox'rFRI~D, D., WARXNG, C. L. & WORTmN% H. N. x959. Lead-alpha age determinations of accessory minerals of rocks (i953-I957). Bull. U.S. geol. Surv. xo97-B. SILVER, L. T., Sa'EHLX, F. G. & ALLEN, C. R. I963. Lower Cretaceous pre-batholitic rocks of northern Baja California. Bull. Amer. Ass. Petrol. Geol. 47, 2o54-9. [R. Casey]

Stratigraphical comment. Pre-batholitic rocks of northern Baja California are said to be as young as Albian, though their fossils do not include ammonites. Some of these rocks are probably not much older than the plutonic rocks that have intruded them. An interval of movement and erosion followed the plutonic episode and preceded deposition of Maestrichtian rocks. The abstractor considers the Pb-~ date (99m.y.) to be more in accord with an Albian age than the concordant U-Pb age of x 15 m.y. The U-Pb date obtained from this intrusion is, however, close to that calculated for volcanic rocks of presumed Middle Albian age in British Columbia (see Item 2o3). R. Casey

Radiometric comment. See Item i89. A. G. Smith

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(2all) Vik~g Form~tlon L. Cretaceous/L. Cretaceous (1, 2, 3) Armena; (4) Majeau Lake; (5) Burbank, Alberta, Canada.

Radiometric age K-Ar (2p = 4"76 × IO-x°year-a; 2e = 0"589 × Io-l°year-t; 4°K/K = o.o118 at. %)

Sample K (%) 4°Ar*#°K Age (m.y.) (x) ~ I22 (bentonitic clay) I"23 0"00249 42 (2) ~ 117 (glauconite) 4" 12 o. oo351 59 (3) AK 17 (glauconite) 4" 12 o. 00493 82 (4) AK 1 I (glauconite) 4" 12 o.oo449 75 (5) r~ 157 (glauconite) 3" 88 o.oo44 3 74 o. 00454 76

Stratigraphical age. Lower Cretaceous (Upper Albian).

R~YelV/tTg FOLINSBE~, R. E., B~O,DSO~O, RD, H. & LmSON, J. i96o (see Item IO). [R. Casey]

Radiometric comment. These values are much too low, the glauconltes giving the age of the (late Cretaceous) Laramlde orogeny. The authors suggest there is a relationship between these low values and load and orogenic history. R. Casey

(2x9) Mmmaville Forrmatlon L. Cretaceous/L. Cretaceous Sprucefield, Alberta, Canada (oil well).

Radiometric age K-Ar (2# = 4"76 × Io-l°year-l; ~ = 0"589 × IO-x°year-a; 4°K/K = o.oii8 at. %) Glauconite AK-56: K = 4"86%, 4°Ar*#°K = o'oo657, age: Io8m.y.

Stratigraphical age. Lower Cretaceous (Middle Albian).

RffeY~7/ce FOLmSSE% R. E., BAADSOAmU~, H. & LIPSON, J. I96O (see Item Io). [R. Casey]

(2~o) Lower Cretaceous sdhnents L. Cretaceous/L. Cretaceous Northern Caucasus, U.S.S.R.

Radiometric age K-Ar (2 B = 4"72 × IO-l°year-X; ;re = 0"557 × Io-X°year-a; 4°K/K = x "22 × IO-4 g/gK) Glauconite: K = 4"43 :k o. I3% , 4°At* = I78 -b 2 mmS/g (x Io4), 4°Ar*#°K = [o'oo589], age: Io 3 [98] 4-4m.y.

Stratigraphical age. Lower Cretaceous ('transitional from Upper Aptian to Lower Albian').

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/tems Reference RUBINSTmN, M. M. 1961 (sec Item 85). [R. Cascy]

Radiometric comment. This figure is close to that obtained from glauconite from the same general atratigraphical level at Salzgltter, Germany (Item 6o), but is too low by igneous standards. Rubinstein (I96 t) suggests loss of argon to explain the low value. R. Casey

(22x) Upper Apti~n or basal Cenomani~n sediments U. Cretaceous]L. Cretaceous I km south of La Foux, Basses-Alpes, France.

Radiometric age K-Ar (A# = 4"72 × IO-t°year-X; ~ = o'585 × Io-X°year-t) Glauconite e-33o5: K = 5"44%, 4°Ar*/4°K = o'oo526, air corm = 42%, age: 87m.y.

Stratigraphical age. Cretaceous (Upper Aptian [s/c., recte Upper Albian] or basal Cenomanian).

Reference HURLEY, P. M. et al. (see Item I3). [R. Cascy]

(222 and s23) Lower Cretaceous sediments L. Cretaceous/L. Cretaceous 2 km north-we.st of Escragnollcs, en route to Castcllane, Alpcs-Maritimes, France.

Radiometric age K-Ar (AS = 4"72 × Io-l°year-t; ;re = 0"585 × IO-x°year-1)

Glauconite K (%) 4°Ar*/4°K air corm (%) Age (m.y.) G-33o3 5" 71 o" oo550 18 88 [92] o-33o4 5" 85 o- oo63 7 xo4 4- 8

Stratigraphical age. Lower Cretaceous (Valanginian-Hauterivian boundary).

Reference HURLEY, P. M. et al. 196o (see Item I3). JR. Casey]

(224) Na~ttoch 'WaslMngton greensm~d' U. Cretaceous/U. Cretaceous i/8 mile north-east of station at Washington, Arkansas, U.S.A.

Radiometric age K-At (Jl# ----- 4.72 × io-~°year-1; tle -- 0"585 × xo-X°year-x) Glauconite G-3242: K = 5"85%, 4°Ar*#°K = 0"0055, air corrn ---- 20%, age: 9 ° [92] 4- Iom.y.

Stratigraphical age. Upper Cretaceous. 396 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Referol, ce HURLEY, P. M. et al. I96o (see Item 13). JR. Casey]

Stratigraphical and radiometric comments. The Nacatoch Sand of Arkansas and Texas is part of the Navarro Group oft he southern United States, which is approximately equivalent to the Maes- trichtian Stage of Europe (Stephenson 194I ). The radiometric age is therefore higher than would be expected. If there were a known stratigraphical break beween the Nacatoch Sand and the underlying beds, this would strengthen the suggestion that the glauconite is derived.

Reference SaXPX-mNSON, L. W. I94I. The larger invertebrate fossils of the Navarro Group of Texas. Bull. Univ. Texas 4tot. R. Casey

(225) Upper Cretaceous sediments U. Cretaceous/U. Cretaceous Krlstianstad, Sweden.

Radiometric age K-Ar (,~p = 4.72 × io-lOyear-1; he = 0"585 × Io-l°year-a) Glauconite o-3675: K = 5"62%, 4°Ar*/4°K : 0.00553, air corm : I6~/o, age: = 88 [92] m.y.

Stratigraphical age. Upper Cretaceous.

Reference HURLEY, P. M. et al. 196o (see Item 13). [R. Casey]

Stratigraphical comment. The authors give no further stratigraphical data to enable the position of the sample in the Upper Cretaceous to be fixed. R. Casey

(226) Bentonite in Cretaceous shale U. Cretaceous/U. Cretaceous Cache Creek, California, U.S.A.

Radiometric age K-Ar (2~ ----- 4"72 × Io-l°year-1; 2e = 0"584 × Io-X°year-1) Biotite KA 4O4: K = 6" x5%, 4°Ar*#°K = o'oo575, arm. 4°Ar = 9%, age: 96m.y.

Stratigraphical age. Cretaceous ( ? Upper Cenomanian). 'The bentonite occurs in a thick (5000 ft 4-) shale approximately 5oo ft stratigraphically beneath the contact with the Venado formation. Fossils approximately 25o ft stratigraphically above the bentonite have been identified as Ceno- manian-Turonian ... Inoceramus cf. labiatus in the Venado formation indicates early Turonian age. Fossils several thousand feet lower than the contact with the Venado formation in Putah Creek, 25 miles to the south, have been tentatively identified as Upper Albian in age... Appears to be an excellent date in the lower part of the Upper Cretaceous.' Reference EVERNDEN, J. F. et al. 196I (see Item 49)- JR. Casey]

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Items

(227) Upper Greensand U. Cretaceous/L. Cretaceous Top of Telegraph Hill, Haldon Hills, Devon, England

Radiornetric age K-Ar (hp : 4"72 × Io-aOyear-1; he = o'584 × Io-l°year-1) Glauconite KA I98: K = 4"95%, 4°Ar*/4°K = °'°°54I, atm. 4°Ar---- I8%, age: 9Im.y.

Stratigraphical age. 'Upper Cretaceous (basal Cenomanian, Pecten asper Zone).'

Reference EWaND~r% J. F. et al. x 96 I. [R. Casey]

Stratigraphical comment. 'Pecten asper Zone' is an obsolete term for a facies belt within the Upper Albian and Lower Cenomanian. In the Haldon Hills the Upper Greensand is of Upper Albian age. R. Casey

(228) Albion sedlnaents L. Cretaceous/L. Cretaceous Core from 43om depth near Salzgitter, Germany.

Radiornetric age K-Ar (h# = 4"72 / xo-a°year-1; he = 0"584 × IO-x°year-a) Glauconite KA 274: K = 5"87%, 4°Ar*/4°K = 0"00584, atm. 4°Ar = 29% , age: 97m.y.

Stratigraphical age. Lower Cretaceous (Albian).

Reference EVEm~DRN, J. F. et al. x 96 x [R. Casey]

(229) Santonlan sediments U. Cretaceous/U. Cretaceous Core from well near Salzgitter, Germany.

Radiornetric age K-Ar (2p = 4"72 × IO-x°year-1; ~ = 0'584 × Io-l°year -x) Glauconite HA 323: K = 4"78%, 4°Ar*/4°K = 0"00494, atm. 4°Ar = 34%, age: 83m.y.

Stratigraphical age. Upper Cretaceous (Lower Santonian).

Reference EVERNDEN, J. F. et al. 1961 [R. Casey]

(23o) Alblan sedlnaents L. Cretaceous/L. Cretaceous Core from well near Salzgitter, Germany. 398 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

//eros

Radiometric age K-Ar (~p-~ 4"72 × IO-a°year-1; ~ =-0"584 × IO-x°year-1) Glauconite x~ 3Io: K = 5"88%, 4°Ar*/4°K = o'oo56o, atm. 4°At = x9%, age: 94m.y.

Stratigraphical age. Lower Cretaceous (Lower Albian).

Reference EWRNW.N, J. F. et al. 196 x. [R. Casey]

(23 I) Lower Cretaceous sedinaents L. Cretaceous/L. Cretaceous Core from well near Salzgitter, Germany.

Radiometric age K-Ar (itB = 4"72 × xo-l°year-1; L: = 0"584 × Io-X°year-1) Glauconite XA 3iI: K = 5"43%, 4°Ar*/4°K = o'oo,85, atm. 4°Ar = 77%, age: 31 m.y. 'Indicated age much too young. Burial and heating are probable causes of invalid age.'

Stratigraphical age. Lower Cretaceous (Upper Hauterivian).

Reference EV~RND~N, J. F. et al. I96I. JR. Casey]

(232) Lower Vol~"~- sediments U. Jurassic/U. Jurassic Milne Land, East Greenland [7 °° 45'N, 26°W].

Radiometric age K-Ar (~ ----- 4"72 × Io-l°year-X; he ---- 0"584 × Io-l°year -1) Glauconite 4°Ar*]4°K Age (m.y.) s 8ooi [o.oo7o8 ] i I7-b 3 s 8oo2 [o-oo648] Io6±3

Stratigraphical age. Lower Volgian: s 8oo2, dorsoplanus Zone; s 8ooi somewhat lower.

For full analytical and stratigraphical details see pp. 747-8 [R. Casey]

Rgf~Tetlcg DODSON, M. H., REx, D. C., CASE'Z, R. & ALLEN, P, I964. Glaucortite dates from the Upper Jurassic and Lower Cretaceous. Quart. 07. geol. Soe. Lond. x2o s [this volume], I45-58.

(233) Clearwater Fornaatlon L. Cretaceous/L. Cretaceous Mannville Group, Alberta, Canada.

Radiometric age K-Ar (No details seen by abstractor). Glauconite: Ages: 75 a, 78 a, 99 ~, I o9 ~, I 15~ m.y. (see also Item 2 x9) 399 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Stratigraphical age. 'Early Middle Albian'. Reference WILLIAMS, G. D., BAADSOAARD, H. & STEEN, G. 1962. Potassium-argon dates from the Mannville Group. 07. Alberta Soc. Petrol. Geol. xo, 32o- 5 (fide Dodson et al. 1964). [R. Casey]

(234) Upper Volgltm sediments U. Jurassic/U. Jurassic Valley of River Bitsa, Ermolino, about 25 km south of Moscow, U.S.S.R.

Radiometric age K-Ar (~p = 4"72 × lO-x°year-1; ~ = 0"584 × xo-l°year-1) Glauconite s 8oo6: *°Ar*/*°K = [o.oo718], age: x t 9 4- 3m.y.

Stratigraphical age. Upper Volgian: subditus Zone.

Reference. See Item 232. [R. Casey]

(235) Ryazaat Beds (upper part) L. Cretaceous/L. Cretaceous Right bank of River Oka, Chevkino, about 6o km south-east of Ryazan, U.S.S.R.

Radiometric age K-Ar (/tp = 4.72 x xo-X°year-1; he ---- o'584 × IO-l°year-X) Glauconite s 8oo7: 4°Ar*#°K = [o.oo7o7], age: II 7 4- 3m.y.

Stratigraphical age. Ryazanian: stenomphalus Zone.

Reference. See Item 232. [R. Casey]

(236) Speeton Clay L. Cretaceous/L. Cretaceous Yorkshire, England.

Radiometric age K-Ar (~p = 4.72 × lO-x°year-1; 3, = 0-584 × xo-X°year-a) Glauconite 4°Ar*#°K Age (m.y.) s 8oo 9 [0.00687] 114+ 3 s 8o I o [o- oo648] xo8 ± 3 s 8ox x [o'oo653] IO9+3

Stratigraphical age. Lower Cretaceous: s 8009, base of Lower Hauterivian; s 80 i o, Middle Hauteri- vian; s 8ox I, base of Lower Barremian.

Reference. See Item 232. [R. Casey] 400 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

(237) Upper Alblan sediments L. Cretaceous/L. Cretaceous Vyselki borehole, Fore-Caucasus, U.S.S.R.

Radiometric age K-Ar (~# = 4"9 × Io-l°year-1; ~ = 0.602 × Io-X°year-1) Glauconite: K = 4-41%, 4°Ar* = 0.384 × 1o-7 g/g, 4°Ar*/4°K = o'oo72, age: x 14 [I x9]m.y.

Stratigraphical age. Lower Cretaceous (Upper Albian). Reference KAZAKOV, G. A. & POL~VAYA, N. I. x958 (see Item I2). JR. Casey]

(238) Ceno~n~n Platform deposits U. Cretaceous/C. Cretaceous Gorodenko, Lvov region, U.S.S.R.

Radiometric age K-Ar (;tB = 4"72 × xo-l°year-X; ;re = 0"557 × xo-X°year-1) Glauconite: K = 7"oo%, 4°Ar* ~ 0"355 X Io -7 g/g, 4°Ar*#°K = [o'oo416], age: 75 [7o]m.y.

Stratigraphical age. Upper Cretaceous (Cenomanlan).

Reference SEMENENKO, N. P., LADIZHENSKIY, N. R., KOTLOVSKAYA,F. I. • VETSHTEYN, V. E. I963. Absolute age of geological formations of the Carpathians. Trudi 8essii Ifomissii po O~bredecleniyuAbsolyut- nogo Vozrasta Geologicheskikh Formatsii, xx, xo4-I8 [in Russian]. JR. Casey]

(239) Senon;~n sediments U. Cretaceous/U. Cretaceous Lisa Mountain, Saratov, Volga Basin, U.S.S.R.

Radiometric age K-Ar (2B = 4"72 × xo-l°year-a; he = o'557 × xo-l°year-1) Glauconite: K = 6.o2%, 4°Ar*/~°K ----- o.oo45 , age 79 [75"5]m.Y •

Stratigraphical age. Upper Cretaceous (Senonian).

Reference POLEVAYA, N. I., MURINA, G. A. & KAZAKOV, G. A. x96I (see Item 2o). JR. Casey]

(240) Lower Greensand (Femglnous Sands) L. Cretaceous/L. Cretaceous Coastal section, Isle of Wight, England.

Radiometric age K-At (gt~ = 4"72 × IO-l°year-t; ;re = 0"584 × Io-l°year-a) 40 t Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Glauconite 4°Ar*/4°K Age (m.y.) s 8012 [o. 00607] i oI 4- 3 s 8o 13 [o-oo566] 944- 3

Stratigraphical age. s 8o12, Lower Aptian, bowerbanki Zone, meyendorff Subzone; s 8o13, Upper Aptian, jacobi Zone, probably nolani Subzone.

Reference. See Item 232. [R. Casey]

(24 x) Lower Greensand (Folkestone Beds) L. Cretaceous/L. Cretaceous Wrecclesham, Surrey, England.

Radiometric age K-Ar (~B = 4"72 × Io-l°year-1; ~-----0'584 × Io-X°year -1) Glauconite s 8o14: 4°Ar*/4°K = [o.oo746], age 124 4- 3 m.y.

Stratigraphical age. Lower Albian; mammillatum Zone.

Reference. See Item 232. [R. Casey]

Radiometric comment. The stratigraphical age of this sample is firmly fixed by palaeontology (Casey 196I) but the radiometric age is anomalously high. What is known of the environment of deposition suggests that Jurassic glauconites could have contributed to the sediment. Phosphatic nodules from this bed at Wrecclesham are among those with a high radioactive content, giving fl-activity readings of up to o'ox5% U3Os (Ponsford I955, p. 42).

References CASEY, R. 196I. The stratigraphical palaeontology of the Lower Greensand. Palaeontology, Lond. 3, 487-62 i. PONSFORD, D. R. A. I955. Radioactivity studies of some British sedimentary rocks. Bull. geol. Surv. G.B. xo, 24-44. R. Casey

(242) Lower Gault L. Cretaceous/L. Cretaceous Depth 54 ft in borehole, Sussex, England.

Radiometric age K-Ar (4# = 4"72 × Io-l°year-1; he = 0"584 × IO-l°year-1) Glauconite s 8o 15 : 40Ar, #o K _ [o. oo588], [o. oo 578], mean age: 98 4- 3 m.y.

Stratigraphical age. Middle Albian, base of dentatus Zone.

Reference. See Item 232. [R. Casey]

Radiometric comment. This sample is from the same stratigraphical level as that of Item 5I; both give young ages. In south-east England this horizon is characterized by glauconitic sandy clays 402 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems with septarian phosphatic nodules. The nodules are less radioactive than those from the underlying mammillatum Zone at Wrecclesham and elsewhere (Item 24I ) and the radioactivity is generally confined to the surfaces of the nodules (Ponsford :955, PP. 42-3).

Reference PONSFORD, D. R. A. (see Item 24I ). R. Casey

(243) Bruneau basalts, youngest flow Pleistocene]Pleistocene Bennett Mountain quadrangle, Elmore County, Idaho, U.S.A.

Radiometric age K-Ar (2~ = 4"72 × Io-l°year-:; ~e ~---0"585 × IO-1°Year-l) Basalt, whole-rock KA x 188: K = o'62%, atm. 4°At = 56%, age: I "36bm.y. (Evernden et al. x964, pp. : 64, x9 x).

Stratigraphical age. Irvingtonian, interbedded with Mammuthus-bearing sediments (Evernden et al. I964, p. I9I).

References EVERNDEN, J. F. et al. I964. (see Item 27). MALDE, H. E. & POWERS, H. A. I962. Upper Cenozoic stratigraphy of Western Snake River Plain, Idaho. Bull. geol. Soc. Amer. 73, 1 i97-22o. [B. M. FunneU]

Stratigraphical comment. The Irvlngtonian was regarded by Durham, Jahns & Savage (:954, fig- 2) as post-Calabrian, i.e., Pleistocene in age.

Refe~'8//ge DvgrmM, J. W., JArrNS, R. H. & SAVAGE, D. E. 1954" (see Item 26). B. M. Fun_nell

(244) Basalt, Valros Pleistocene/Pliocene Agde region, H6rault, France

Radiometric age K-Ar (,1~ = 4"72 × Io-:°year-X; ;re = 0"585 × Io-:°year -:) Basalt, whole-rock gA II84: K ----- o'799%, atm. 4°At ---- 95%, age: x "61bm.y. (Evemden et al. I964, pp. I7o, I9: ).

Stratigraphical age. Overlies Astian-Plaisancian, underlies Villafranchian (Evernden et al. I964, pp. I7o, t9I).

References EVERNDEN, J. F. et al. x964 (see Item 27). KLOOSTERMAN,J. B. 196O. Le volcanisme de la r~gion d'Agde, H6rault, France. Geologica Ultraiec- tina, 6, x-79. lB. M. Funnell] 4o3 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Stratigraphical comment. Kloosterman (I96O , p. 64) regarded the Valros volcano as occurring between the Astian and Villafranchian; all that is certain, however, is that it rests on a fluviatile gravel assigned to the Pliocene moyen (Astian) by Deperet, and it is not overlain by a coarse gravel that Deperet attributed to the Villafranchian.

Reference KLOOSTERMANN,J. B. 196o (see above). B. M. Funnell

(245) Tufts, Olduval Gorge L. Pleistocene/L. Pleistocene In lower part of Bed I, Olduvai Gorge, Tanganyika.

Radiometric age K-Ar (~p = 4"72 × Io-X°year-X; ~¢ = 0"584 × Io-l°year -x) Anorthoclase Mass 4°Ar* (mole/g (g) × IOu) K(%) 4°Ar*/4°K (x Io 4) atm.4°Ar (%) Age (m.y.) KA 412 29" 6 28" 3 3" 29 [O" 953] 67 1" 63 KA 437 6"68 6"62 3.06 [1.062] 7 ° I "74 [I '82] KA 846 7"91 5"55 2"52 [O'913] 52 1 "57 KA 847 5 "9° 6" I6 3" I8 [X "O76] 7O X"85 KA 849 6"5 ° 4"44 2 "O4 [I "O98] 77 1 "89 KA 85O 8" I7 IO'20 3"94 [X "O39] 41 X"78 KA 851 7" 79 8" 37 3" 69 [O" 955] 61 1" 64 Average age: I'75 [~ o'o5]m.y. (Leakey, Evernden & Curtis, 1961, p. 479); I'75m.y. (Evernden et al. 1964, pp. 17% 171 ).

[An exhaustive reconsideration of radiometric ages from the Olduvai section, including both new determinations and re-runs of previous material by improved methods, is contained in Evernden & Curtis (in the press). The improved data now available do not affect the average value of 1 "75 m.y. previously published.]

Stratigraphical age. Lower Pleistocene (Villafranchian) (Leakey, Evemden & Curtis, 196 I, p. 478).

References EV~RNDEN, J. F. & CURTIS, G. H. The potassium-argon dating of late Cenozoic Rocks in East Africa and Italy. Current Anthropology [in the press]. EVXRNDEN, J. F. et al. 1964 (see Item 27). L~AK~y, L. S. B., EVERNDEN, J. F. & CURTIS, G. H. 1961. Age of Bed I, Olduvai Gorge, Tanganyika. Nature, Lond. x9x, 478-9. [B. M. Funnell]

Stratigraphical comment. There has been considerable dispute over the stratigraphical age of the lower part of Bed I at Olduvai (,con Koenigswald, Gentner & Lippolt 1961 ; Oakley I962, p. 42o; Leakey 1962 ; ,con Koenigswald I962, etc.), but it seems unlikely to be anything other than Villafranchian.

References KOENIGSWALD, G. H. R. VON. 1962. Age of basalt underlying Bed I, Olduvai. Nature, Lond. t94, 6II. 4o4 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

KOENIGSWALD, G. H. R. VON, GENTNER, W. & LIPPOLT, H.J. 196I. Age of the basalt flow at Olduvai, East Africa. Nature, Lond. 192 , 72o-1. LEAKEY, L. S. B. I962. Age of basalt underlying Bed I, Olduvai. Nature, Lond. I94 , 61o-1 i. OAKL~Y, K. P. I962. Dating the emergence of Man. Advanc. Sci. Lond. I8, 415-26. B. M. Funnell

(246) Sutter Formation intrusion Plio-Pleistocene/Plio-Pleistocene Sutter Buttes, California, U.S.A.

Radiometric age K-Ar ()'B = 4"72 × I°-l°year-X; ~e ~ 0'585 × 1o-1°Year-l) Biotite KA 490: K = 7.42% , atm. *OAr = 75%, age: x .9bm.y. (Evernden et al. 1964, pp. I64, I79).

Stratigraphical age. Late (?) Blancan (Evernden et al. 1964, p. x79 ).

References EVERNDEN, J. F., CURTIS, G. H. & LXPSON,J. 1957. (see Item io8). EVERNDEN, J. F. et al. I964. (see Item 27). STmTON, R. A. 1936. SuccessiorL of North American continental Pliocene mammalian faunas. Amer. 07. Sci. 32, I6I-2O6. lB. M. Funnell]

Stratigraphical comment. Thenius (I 959, P. 288) regarded the whole of the Blancan, and Durham, Jahns & Savage (I954, fig. 2) only its upper part as equivalent to the Villafranchian. Late Blancan probably implies a Pleistocene age.

References DURHAM, J. W., JAHNS, R. H. & SAVAGE, D. E. I954 (see Item 26). Trmmus, E. i959. Terti~r: Wirbeltier Faunen. Stuttgart (F. Enke). B. M. Funnell

(~47) Andeslte, overlying lacustrine Coso Formation Plio-Pleistocene/Plio-Pleistocene Southern Coso Mountain, California, U.S.A.

Radiometric age K-At (2p = 4"72 × Io-l°year-1; 2e = 0"585 × xo-X°year-1) Biotite KA xO26: K = 6.oo%, atm. 4°Ar = 76%, age: 2.o b, 2" Ibm.y. (Evernden et al. 1964, pp. 164, 189--9o).

Stratigraphical age. Probable Late Blancan; above Coso Mountain fauna (Evernden et al. I964, pp. 164, x9o). References EVERNDEN, J. F. et at. I964 (see Item 27). HmBAmJ, C. W. 1958. Summary of North American Pleistocene mammalian local faunas. Pap. Mich. Acad. Sci. 43, 3-32. SeI-IULTZ, J. R. I937. A late Cenozoic vertebrate fauna from the Coso Mountains, Inyo County, California. Publ. Carneg. Instn, 487, 75-IO9. STIRTON, R. A. 1936 (see Item 246). lB. M. FunneU] 405 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Stratigraphical comment. See Item 046. B. M. Funnell

(248) Pumice, in water-laid tuff, Coso Format/on Plio-Pleistocene/Plio-Pleistocene Coso Mountain, Keeler quadrangle, California, U.S.A.

Radiometric age K-Ar (Aa ---- 4" 70 x Io-l°year-1; ~te----0"585 × IO-l°year -1) Biotite XA 451 : K = 3"o1%, atm. 4°Ar ~ 96%, age: o.o b, o.3bm.y. (Evernden et al. 1964, pp. 164, I77).

Stratigraphical age. Late Blancan; Coso Mountain fauna (Evernden et al. I964, pp. i64, 177 ).

References. See Item 047. lB. M. Funnell]

Stratigraphical comment. See Item 047. B. M. Funnell

(249) Tuff, near base of TehAtna Fortnatlon Plio-Pleistocene/Plio-Pleistocene Bear Creek Falls, Shasta County, California, U.S.A.

Radiometric age K-Ar (~ = 4'70 × Io-l°year-X; 2e = 0"585 × Io-l°year -1) Plagioclase KA 587 : K ---= 3.04%, atm. 4°At ----=9I%, age: 3"3bm.y. (Evernden et al. I964, pp. t 64, 18o).

Stratigraphical age. Late (?) Blancan; Tehama fauna (Evernden et al. 1964, pp. 164, x80).

References EVERNDEN,J. F. et al. I964 (see Item 27). RUSSELL, R. D. & VANDERHOFF, V. L. x93 I. A vertebrate fauna from a new Pliocene formation in northern California. Bull. Dept. Geol. Univ. Calif. ao (2), x 1-21. STIRTON, R. A. 1936 (see Item 047). []3. M. Funnell]

Stratigraphical comment. See Item 25o, or, if attribution to the late Blancan is justifiable, see Item 046 , i.e., a Pliocene or early Pleistocene or Pleistocene age. B. M. Funnell

(250) Basalt~ Glenns Ferry Forn~at/on Plio-Pleistocene]Plio-Pleistocene Pasadena Valley quadrangle, Elmore County, Idaho, U.S.A.

Radiometric age K-Ar (AB = 4"72 × IO-l°year-X; J~e = 0"585 × lo-X°year-a) Aggregates of fresh plagioclase and pyroxene KA ii73: K-~ o'232~, atm. 4°Ar ----92~/o, age: 3"48b -4-o'27m.y. (Evernden et al. I964, pp. 164, 191 ). 4o6 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Stratigraphical age. Blancan; Hagerman fauna (Evernden et al. 1964, pp. I64, I84, I91 ).

References EVERNDEN,J. F. et al. x964 (see Item 27). HIBBARD, C. W. I958 (see Item 247 ). 1959. Late Cenozoic microtine rodents from Wyoming and Idaho. Pap. Mich. Acad. Sci. 44, 3-4 ° . MALD% H. E. & POWERS, H. A. I962 (see Item 243). [B. M. Funnell]

Stratigraphical comment. Thenlus (i959, p. 288) regarded the whole of the Blancan, and Durham, Jahns & Savage (I954, fig. 2) only its upper part, as equivalent to the Villafranchian. Blancan implies a Pliocene or early Pleistocene age.

References. See Item _046. B. M. Funnell

(25 x) Basalt, Bi~alltoehi Formation Pliocene/Pliocene Lava-flow 40 miles north of Holbrook, Arizona, U.S.A.

Radiometric age K-Ar (~p ---- 4" 72 × Io-l°year-X; he = 0"585 × xo-l°year-1) Basalt, whole-rock KA IO27: K ~ I "42%, atm. ~°Ar = 88%, age: 4-Ibm.y. (Evernden et al. 1964, pp. 155, I64, 190).

Stratigraphical age. Late Hemphillian or early Blancan; White Cone fauna (Evernden et al. I964, pp. 164, I9O).

References EVERNDEN,J. F. et al. x964 (see Item 27). REPENNING, C. A. ~l; IRWIN, J. H. 1954. Bidahochi formation of Arizona and New Mexico. Bull. Amer. Assoc. Petrol. Geol. 38, x82I-6. SHOTWELL, J. A. 1955" Review of the Pliocene beaver Dipoides [Oregon]. 07. Paleont. 29, 129-44. STIRTON, R. A. I936. A new beaver from the Pliocene of Arizona, with notes on the species of Dipoides. 07. Mammal. 17, 279-8I. [B. M. Fulmell]

Radiometric comment. Age should be considered a minimum (Evernden et al. 1964, pp. 155, I9O).

Stratigraphical comment. Thenius (i959, p. 288) regarded the whole of the Blancan as equivalent to the Villafranchian, and the Hemphillian as equivalent to the uppermost Pannonian and the Piacenzian-Astian. Durham, Jahns & Savage (1954, fig. 2) correlated the Blancan with the Astian and Calabrian, and the Hemphillian with the Pontian and Plaisancian. Late Hemphillian or early Blancan implies a Pliocene, possibly earliest Pleistocene, age.

References. See Item 246 . B. M. Funnell

(25~) Piuole tuft Pliocene/Pliocene Exposure 2000 yards west of Pinole junction, Contra Costa County, California, U.S.A. 4o7 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Radiometric age K-At (2p = 4"72 × xo-X°year-'; 2e = 0"585 × Io-X°year -x) Feldspar KA ,OO5: K -----8"37%, arm. 4°At -----57%, age: 5"2bm.y. (Evernden et al. I964, pp. '64, 188).

Stratigraphical age. Late Hemphillian; Pinole fauna (Evernden et al. x964, pp. I64, ,88).

References EVEm~D~N, J. F. et al. t964 (see Item 27). STmTON, R. A. ,939. Cenozoic mammal remains from the San Francisco Bay region. Bull. Dep. Geol. Univ. Calif. 24, 339-4o9 • [B. M. Funnell]

Stratigraphical comment. Thenius (x959, p. 288) regarded the Hemphillian as equivalent to the uppermost Parmonian and the Piacenzian-Astian. Durham, Jahns & Savage ('954, fig. 2) regarded it as equivalent to the Pontian and Plaisancian. Late Hemphillian implies a Pliocene age.

References. See Item 246 . B. M. Funnell

(253) Rhyolite, Rattlesnake Formation Mio-Pliocene/Mio-Pliocene In road cutting on north side of Highway 26, ,o'6 miles east of Dayville, Oregon, U.S.A.

Radiometric age K-Ar (2# = 4"72 × xo-X°year-X; )~= 0"585 × xo-t°year -a) Sanidine g~. I2o6: K = 3.854%, atm. 4°Ar = x6%, age: 6.4bm.y. (Evernden et al. x964, pp. t64, ,9x-2).

Stratigraphical age. Hemphillian: Rattlesnake fauna (Evernden et al. I964, pp. x64, x92).

References CrmrcEY, R. W. & AXE~OD, D. I. I959. Miocene floras of the Columbia Plateau. Publ. Garneg. Instn 6x7, 1-237. EVlZRNDm~,J. F. et al. x964 (see Item 27). MEres,AM, J. C., STOCK, C. & MOODY, C. L. I925. The Plioeene Rattlesnake formation and fauna of eastern Oregon, with notes on the geology of the Rattlesnake and Mascall deposits. Publ. Carneg. Instn 347, 43-92. [B. M. Funnell]

Stratigraphical comment. Thenius (i959, p. 288) regarded the Hemphillian as equivalent to the uppermost Pannonian and the Piacenzian-Astian. Durham, Jahns & Savage (I954, fig. 2) regarded it as equivalent to the Pontian and Plaisancian. Hemphillian implies a Pliocene or Upper Miocene age.

References. See Item 246 . B. M. Funnell

(254) Tuff, Alturas Formation Mio-Pliocene/Mio-Pliocene Rattlesnake Butte, near Alturas, California, U.S.A. 408 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

.Radiometric age K-Ar (~p = 4"72 × xo-X°year-X; he = 0"585 × Io-l°year -1) Plagioclase ~ I262: K = o'333%, arm. 4°Ar = 86%, age: 8'I b m.y. (Evernden et al. I964, pp. 164, 193).

,Stratigraphical age. HemphiUian; Alturas fauna (Evernden et al. 1964, pp. z64, 193).

.~eference$ AXELROD, D. I. I944. The Alturas floras. Publ. Carncg. Instn 553, °63-84. EVERNDEN, J. F. et al. 1964 (see Item 27). [B. M. FunneU]

Stratigraphical comment. See Item 253. B. M. FunneU

(255) Welded Tuff Member, Drewsey Formation Mio-Pliocene/Mio-Pliocene Summit of Drinkwater Pass, Owyhee Plateau, Malheur County, Oregon, U.S.A.

Radiometric age K-Ar (2p = 4"72 × Io-l°yeax-X; Re = o'585 × IO-l°year-1) Sanidine KA 1225: K = 5"8o4%, atm. 4°Ar----- i-5%, age: 8"9bm.y. (Evernden et al. 1964, pp. 164, 192 ) •

Stratigraphical age. Hemphillian; Drinkwater fauna (Evernden et al. 1964, pp. 164, 192).

References EVERND~.N, J. F. et al. I964 (see Item 27). SHOTWXLL, J. A. i963. The Juntura basin; studies in Earth history and paleoecology. Trans. Amer. phil. Soc. 53, 1-77. [B. M. Funnell]

Stratigraphical comment. See Item 253. B. M. Funnell

(256) Obsidian, Teewlnot Formation Mio-Pliocene/Mio-Pliocene Jackson Hole, Grand Teton National Park, Teton County, Wyoming, U.S.A.

Radiometric age K-Ar (2p = 4"72 × IO-x°year-X; 2e ----- o'585 × xo-l°year -1) Obsidian, whole-rock HA 929: K = 4'o2%, atm. 4°Ar = 3I%, age: 9"2bm.y. (Evernden et al. 1964, PP. x64, 185-6).

Stratigraphical age. Hemphillian (Evernden et al. 1964, pp. z64, 185--6).

References COOK, H.J. 1960. New concepts of late Tertiary major crustal deformations in the Rocky Mount- ain region of North America. Int. geol. Gongr. 2t (12) I98-212. EVERNDEN, J. F. et al. 1964 (see Item 27). 409 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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LovF, J. D. I956. New geologic formation names in Jackson Hole, Teton County, northwestern Wyoming. Bull. Amer. Assoc. Petrol. Geol. 4 o, I899-9i 4. MALDE, H. E. & POWERS, H. A. I962. (see Item 243)- lB. M. Funnell]

Stratigra~Ohical comment. See Item 253. B. M. Funnell

(257) Coarse ash, Hole-ln-the-wall Dlatomlte U. Miocene/U. Miocene Stroud Claim, near I-Iagerman, Gooding County, Idaho, U.S.A.

Radiometric age K-Ar (~p = 4"72 × IO-l°year-1; ~ = 0.585 × xo-l°year-1) Coarse ash, whole-rock KA 830: K = 4"72%, arm. 4°Ar = 5~%, age: Io'obm.y. (Evernden et al. i964, pp. i64, I83).

Stratigraphical age. Early Hemphillian: Stroud Claim fauna (Evernden et al. 1964, pp. 164, I83).

Re, fence EVERNDEN, J. F. et al. 1964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. Thenius (i959, p. 288) regarded the Hemphillian as equivalent to the uppermost Pannonian and the Piacenzian-Astian. Durham, Jahns & Savage (I954, fig. 2) regarded it as equivalent to the Pontian and Plaisancian. Early Hemphillian probably implies an Upper Miocene age.

References. See Item 246. B. M. Funnell

Radiometric age K-Ar (2~ = 4"72 x Io-X°year-a; ;re = 0"585 × xo-l°year-x) Plagioclase KA 829: K ---- o'279%, arm. 4°Ar ---- 83%, age: 9-89bm.y. (Evernden et al. 1964, pp. I64, I83).

Stratigraphical age. Late Clarendonian (Evernden et al. 1964, PP. x64, 183).

References EV~RNDEN, J. F. et al. I964 (see Item 27). SAVAO~, D. E. I955. Nonmarine lower Plioeene sediments in California. Bull. Dep. GeoL Univ. Calif. 31 (x), 1-26. STIRTON, R. A. 1939 (see Item 252 ). lB. M. Funnell]

Stratigraphical comment. Thenius (1959, p. 288) regarded the Clarendonian as equivalent to all except the uppermost part of the Pannonian. Durham, Jahns & Savage (I954, fig. 2) regarded it as equivalent to the Sarmatian. Clarendonian implies an Upper Miocene age. 4Io Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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References. See Item 246 . B. M. Funnell

(259) Tuff, l~cardo Fomma¢lon U. Mioeene/U. Miocene Last Chance Canyon, Kern County, California, U.S.A.

Radiometric age K-Ar (2~ = 4"72 = Io-X°year-X; he ----- 0"585 × Io-a°year-x) Biotite KA 453: K = 6"56%, atm. 4°Ar = 7I%, age: 9.8 b, Io'obm.y. (Evernden et al. I964, pp. I64, I77, x93)

Stratigraphical age. Late Early Glarendonian or early Late Clarendonian; Ricardo fauna [given as late Clarendonian on p. x64 of Evernder~ et al. (x964) ] (Evernden et al. I964, pp. I64, I77).

R~f erol£e$ DmBLF~., T. W. I952. Geology of the Saltdale Quadrangle, California. Bull. Calif. Div. Mines x6o, 7-43- EVERNDEN, J. F. et al. I964 (see Item 27). M~RRIAM, J. C. x919. Tertiary mammalian faunas of the Mohave Desert. Bull. Dep. Geol. Univ. Calif. xx, 437-585. Ricrmy, K. A. 1948. Lower Pliocene horses from Black Hawk Ranch, Mount Diablo, California. Bull. Dep. Geol. Univ. Calif. 28, 1-43. TEDFORD, R. H. I96x. Glarendonian Insectivora from the Ricardo Formation, Kern County, California. Bull. S. Calif. Acad. Sci. 60, 57-76. [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell

(26o) T~, Avawatz FormaClon U. Miocene/U. Miocene On south-eastern flank of Avawatz Mountain, approx. I o miles north-west of Silver Lake, California, U.S.A.

Radiometric age K-Ar (;t~ ~ 4"72 × IO-l°year-1; 2e = 0'585 × Io-l°year-1) Sanidine KA I275: K = 4"464%, arm. 4°Ar = 69%, age: io'7bm.y. (Evernden et al. I964, P. ~93).

Stratigraphical age. Clarendonian; Avawatz fauna (Evernden et al. I964, pp. I64, I93).

RefuTe?Ices EVBRND~N, J. F. et al. I964 (see Item 27). H~Nsx-~w, P. C. x939. A Tertiary mammalian fauna from the Avawatz Mountains, San Bernar- dino County, California. Publ. Carneg. Instn, fii4, I-3o. [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell 4i x Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(26I) Tuff, Avawatz Formation U. Miocene/U. Miocene (See Item 260 for locality.)

Radiometric age K-At (2 B = 4"72 × 1o-l°year-1; 2e = 0"585 × lO-l°year-1) Sanidine m~, i365: K = 4"543%, atm. *OAr = 6%, age: I I .obm.y. (Evernden et al. 1964, p. I94).

Stratigraphical age. Clarendonian; Avawatz fauna (Evernden et al. 1964, pp. 164, 194).

References. See Item 260. [B. M. Funnell]

Stratigraphical comment. See Item 258. B.M. Funnell

(262) Tuff, in Aldrich Station Formation U. Miocene/U. Miocene Near top of unit A6, Coal Valley, Nevada, U.S.A. (see also Item ~64).

Radiometric age K-Ar (2p = 4"72 × Io-i°year-1; 2 e = 0"585 × IO-x°year-1) Biotite K (%) atm.a°Ar(%) Age (m.y.) 482 6"76 89 Io'5 b KA 482 (II) 6- 76 90 I I" 2 b (Evernden et al. I964, pp. I64, I78 )

Stratigraphical age. Early Clarendonian: Coal Valley fauna (Evernden et al. I964, pp. 164, 178).

References AX~LROD, D. I. I956 (see Item 26). EVERND~N, J. F. et al. x964 (see Item 27). STmTON, R. A. 1939 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell

(263) Biotite-tuff, Aldrich Station Formation U. Miocene/U. Miocene In unit A6, Coal Valley, Nevada, U.S.A. (below tuff of Item 264).

Radiometric age K-Ar (2p = 4"72 × IO-x°year-X; 2e = 0"585 × IO-l°year -1) Biotite g,~ 552: K = 6"65%, atm. 4°Ar = 9I%, age: I I-obm.y. (Evernden et al. I964, p. I8o).

Stratigraphical age. Early Clarendonian; Coal Valley fauna (Evernden et al. I964, pp. 164, I8o).

References. See Item 262. [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell

412 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(264) Biotite crystal vitrlc tuff, Aldrich Station Formation U. Miocene/U. Miocene Near top of unit A6, Coal Valley, Nevada, U.S.A. (the same tuff as Item 262).

Radiometric age K-Ar (2 B = 4"72 × Io-l°year-X; 2e = 0"585 × Io-l°year-1) Glass-pumice ~ 500: K = 5"37%, atm. 4°Ar = 67%, age: xo'6bm.y. (Evernden et al. I964, P. x79)-

Stratigraphical age. Early Clarendonian; Coal Valley fauna (Evernden et al. I964, pp. x64, I79).

References. See Item 262. [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell

(265) Biotite crystal vltrie tuff, Coal Valley Formation U. Miocene/U. Miocene Approx. 2oo ft above base of unit i of Coal Valley Formation, Coal Valley, Nevada, U.S.A.

Radiometric age K-Ar (2p = 4.72 × io-l°year-1; 2e = o'585 × Io-X°year-1) Biotite KA 551 : K = 6"54%, atm. 4°At = 36%, age xo.8bm.y. (Evernden et al. x964, pp. I64, 179).

Stratigraphical age. Early Clarendonian; Coal Valley fauna (Evernden et al. t964, pp. I64, 179).

References. See Item 262. [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell

(266) Biotite crystal vitrle tuff, Esmeralda Fortnation U. Miocene/U. Miocene Cedar Mountain area, Nevada, U.S.A., about x mile north of 'Tedford Pocket' (see also Item 267).

Radiometric age K-Ar (2p = 4"72 × Io-X°year-1; he = 0"585 × xo-a°year-x) Biotite g.a 452: K = 7.05%, atm. 4°Ar = 64%, age: IO'7bm.y. (Evernden et aL r964, pp. I64, I77).

Stratigraphical age. Early Clarendonlan; above Cedar Mountain fauna (Evernden et al. I964, pp. t64, I77).

References. See Item 27 . [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell 4x3 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(267) Esmeralda Formation U. Miocene/U. Miocene Cedar Mountain area, Nevada, U.S.A., approx. I mile north-west of 'Tedford Pocket' (approx. 5 ° ft higher in section than Item 266).

Radiometric age K-Ar ()~p = 4"72 × Io-X°year-X; ~e = 0"585 × Io-X°Y ear-l) Sanidine ga~ 577: K = 5"94%, atm. 4°Ar -= 33%, age: 11-5bm.y. (Evernden et al. I964, pp. 164, 18o).

Stratigraphical age. Early Clarendonian; Cedar Mountain fauna (Evernden et al. 1964, pp. 164, 18o).

References. See Item 066. [B. M. Funnell]

Stratigraphical comment. See Item ~58. B. M. Funnell

(268) Biotite crystal vltric tuff, Esmeralda Formation U. Miocene/U. Miocene Fish Lake Valley, Nevada, U.S.A. ; 25 ft above micro-mammal level.

Radiometric age K-Ar (2p = 4"72 × lO-l°year-1; 2, = o'585 × IO-a°year-1) Biotite KA 48O: K = 4"64%, atm. 4°Ar = 36%, age: I 1. ibm.y. (Evernden et al. 1964, pp. 164, I77, 193).

Stratigraphical age. Early Clarendonian; Fish Lake Valley fauna (Evernden et al., I964, pp. 164, I77).

References. See Item 266. lB. M. FunneU]

Stratigraphical comment. See Item 258. B. M. Funnell

(269) Biotite crystal vltrie tuff, Esmeralda Formation U. Miocene/U. Miocene Fish Lake Valley, Nevada, U.S.A. (As for Item 268, except that horizon is just below micro- mammal level).

Radiometric age K-Ar (2B ----4"72 × lO-x°year-1; ~ = 0"585 × xo-l°year -1) Biotite r~ 499: K = 6.12%, atm. 4°Ar -= 31%, age: x i "4bm.y. (Evernden et al. I964, pp. 164, 179).

Stratigraphical age. Early Clarendonian; Fish Lake Valley fauna (Evernden et al. 1964, pp. 164, 179).

References. See Item 266. [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell 414 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(270) Intrusion, Grizzly Peak voleanies U. Miocene/U. Miocene Between Orinda and Siesta formations, Little Grizzly Peak, Berkeley Hills, California, U.S.A.

Radiometric age K-Ar (h$ = 4"72 × IO-x°year-1; he = 0"585 X IO-l°year-1) Sanidine xA 559: K = 7"3o%, atm. *°Ar = 66%, age: 8"9bm.y. (Evernden et al. I964, pp. 162, x8o).

Stratigraphical age. Early to late Clarendonian (Evernden et al. I964, p. I8O).

References. See Item 258. [B. M. Funnell]

Radiometric comment. The age may be slightly inaccurate because of a near-by Pliocene-Pleistocene fault (Evernden et al. I964, p. I62).

Stratigraphical comment. See Item 258. B. M. Funnell

(27x) Intrusive glassy basalt, lower Grizzly Peak volcanles U. Miocene/U. Miocene Round Top Peak, Berkeley Hills, California, U.S.A.

Radiometric age K-At (hp = 4"72 × xo-l°year-1; he = o'585 × IO-l°year-a) Glassy basalt, whole-rock x_~ 814: K = I'23%, atm. 4°At = 9x%, age: 9.8 b m.y. (Evernden et al. I964, pp. i55 , I8I).

Stratigraphical age. Post-early Clarendonian, pre-latest Clarendonian (Evernden et aL 1964, p. 18 x).

References. See Item 258. [B. M. Funnell]

Radiometric comment. The age given is considered to be a minimum figure (Evernden et al. I964, pp. I55 , x8I).

Stratigraphical comment. See Item 258. B. M. Funnell

(272) Basalt, Grizzly Peak volemdes U. Miocene/U. Miocene Berkeley Hills, California, U.S.A.; 400 ft above rhyolite marker.

Radiometric age K-Ar (hp = 4"72 × Io-l°year-1; he = o'585 X Io-l°year -x) Basalt, whole-rock m~ 816: K = 1.2o%, atm. 4°At = 86%, age: 9.8bm.y. (Evernden et al. I964, pp. x8I-2).

Stratigraphical age. Post-early Clarendonian, pre-latest Clarendonian (Evernden et al. I964, p. i82). 415 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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References. See Item 258. [B. M. Funnell] Stratigraphical comment. See Item 258. B. M. Funnell

(273) Basalt, Czdzfly Peak voices U. Miocene/C. Miocene Berkeley Hills, California, U.S.A.; 260 ft below rhyofite marker at base of volcanic sequence just above Grizzly Peak-Orinda contact.

Radiometric age K-Ar (~p = 4"72 × Io-X°year-1; ~le = 0'585 × xo-X°year -x) Basalt, whole-rock ga~ 993: K = o.622%, atm. 4°Ar = 7o%, age: tI.7bm.y. (Evernden et d. I964, p. i87).

Stratigraphical age. Post-early Clarendonian, pre-latest Clarendonian (Evernden et al. I964, p. I87).

References. See Item 258 . [B. M. Funnell]

Stratigraphical comment. See Item 258. B. M. Funnell

(274) OIivine-basalt, Grizzly Peak voleanies U. Miocene/U. Miocene Grizzly Peak Boulevard, Berkeley Hills, California, U.S.A.

Radiometric age K-At (,~p- 4"72 × Io-t°year-X; he = 0"585 × xo-l°year -1) Basalt, whole-rock ~ iooi: K = o.412%, atm. i°Ar: 86%, age I I.4 b my. (Evernden et al. I964, pp. I87-8).

Stratigraphical age. [Post-early Clarendonian, pre-latest Clarendonian] (Evernden et al. I964, p. I88).

References. See Item 258. [B. M. Funnell]

Stratigraphical comment. See Item 258. B.M. Funnel1

(275) Biotite pumice lapill|~ Miocene tuffaceous sandstone U.-M. Miocene/U.-M. Miocene About Io ft above undescribed Barstovian mammal assemblage, western Cronese basin, Cali- fornia, U.S.A.

Radiometric age K-Ar (/l# = 4"72 x Io-l°year-1; ~ = 0"585 × xo-t°year -1) K (%) atm.4°Ar (%) Age (m.y.) Biotite ~ i368 3"2o4 70 12" 3 b Plagioclase g~ 1372 o. 359 36 I x.5 b (Evernden et al. x 964, pp. z 64, 194) 416 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical age. Latest Barstovian--earliest Clarendortian; Cronese Basin fauna (Evernden et al. 1964, pp. I64, 194).

Referg?/gg Exr~gNVrr~, J. F. et al. I964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. Thenius (i959, p. 288) regarded the Clarendonian as equivalent to all but the uppermost part of the Pannonian, and the Barstovian to all but the lowest part of the Vindobonian. Durham, Jahns & Savage (1954, fig. 2) regarded the Clarendonian as equivalent to the Sarmatian, and the Barstovian as equivalent the upper Helvetian and Tortonian. Latest Barstovian-earliest Clarendonian therefore implies a position near the Middle-Upper Miocene boundary.

References. See Item 246 . B. M. Funnell

(~76 and 277 ) Steens Basalt M. Miocene]M. Miocene Steens Mountain, Harney County, Oregon, U.S.A.

Radiometric age K-At (2p = 4"72 × lO-x°Year-1; 2e = 0"585 × Io-lOyear-X) K (%) atm.'OAr (%) Age (m.y.) Basalt, whole-rock g.A 1165 I. 364 60 14.5 b Plagioclase g.~ x251 o. 305 42 14" 7 b (Evernden et al. I964, p. I9o, I92)

Stratigraphical age. Barstovian; Beatys Butte fauna (Evernden et al. I964, pp. I64, I9o--2).

R~fer6,;~ EVEm~EN, J. F. et al. 1964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. Thenius (x959, p. 288) regarded the Barstovian as equivalent to all but the lowest part of the Vindobonian; Durham, Jahns & Savage (I 954, fig. 2) regard it as equivalent to the upper Helvetian and Tortonian. Barstovian therefore implies a Middle Miocene age.

References. See Item 246. B. M. Funnell

(278) Vttrle taft, at top of Sheep Creek Fornmtlon M. Miocene/M. Miocene Vance Johnson Ranch, Sioux County, Nebraska, U.S.A.

Radiometric age K-Ar (2B = 4"72 × xo-l°year-X; ~ = o'585 × IO-x°year-x) Ash KA 891 : K = 4"78%, atm. 4°At = 58%, age: I4"7bm.y. (Evernden et al. I964, pp. 164, I84).

Stratigraphical age. Late Barstovian (Evernden et al. 1964, p. I84). 417 P Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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References COOK, H.J. & COOK, M. C. 1933. Faunal lists of the Tertiary Vertebrata of Nebraska and adjacent areas. Pap. geol. Surv. Neb. 5, 1-58. EV~RND~N, J. F. et al. 1964 (see Item 27). OSBORN, H. F. I918. Equidae of the Oligocene, Miocene and Pliocene of North America, icono- graphic type revision. Mem. Amer. Mus. nat. Hist. 2 (i), 1-33o. WOOD, H. E. et al. I94I (see Item 26). [B. M. Funnell]

Stratigraphical comment. See Item 276. B. M. Funnell

(279) Tuff, Payette Format/on M. Miocene/M. Miocene Red Ridge Basin, Malheur County, Oregon, U.S.A. In same unit as original Skull Springs fauna.

Radiometric age K-At (itD = 4"72 × IO-x°year-1; 2e = 0"585 × Io-l°year -1) Sanidine KA XO29: K = 3"95%, atm. 4°Ar = 9%, age: I5.obm.y., 15" Ibm.y. (Evernden et al. 1946, pp. 164, 19o).

Stratigraphical age. Early (?) Barstovian; Skull Springs fauna (Evernden et al. 1964, PP. 164, 190).

References DoWNs, T. I956. The Mascall fauna from the Miocene of Oregon. Bull. Dep. Geol. Univ. Calif. 3 i, I99-354. EVERI~rDEN, J. F. et al. I964 (see Item 27). GAzm, C. L. i932. A Miocene mammalian fauna from southeastern Oregon. Publ. Carneg. Instn 4t8, 37-86. [B. M. Funnell]

Stratigraphical comment. See Item 276. B. M. Funnell

(o80) Miocene basalt L.-M. Miocene/L.-M. Miocene Underlying Mascall flora-containing tuff of Mascall Formation, Columbia River Basalts. Road cutting on Highway 28, 13 miles east of Dayville, Oregon, U.S.A.

Radiometric age K-Ar (/t/~ = 4"72 × IO-x°year-a; he-----0"585 × IO-x°year-a) Basalt, whole-rock KA X203: K = o'646 %, atm. 4°At = 92%, age: IS'4bm.y. (Evernden et al. x964, pp. x64, 19 x).

Stratigraphical age. Hemingfordian-Barstovian; Mascall fauna (Evernden et al. x 964, pp. 164, 191 ).

References CHANEY, R. W. & AXELROD, O. I. x959 (see Item 253). DOWNS, T. x956 (see Item 279). EVERND~N, J. F. et aL I964 (see Item 27). lB. M. Funnell] 418 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. Thenius (1959, P. 288) regarded the Barstovian as equivalent to all except the lowest Vindobonian, and the Hemingfordian as equivalent to the upper Burdigalian and lowest Vindobonian. Durham, Jahns & Savage (z954, fig. 2) regarded them as equivalent to the upper Helvetian and Tortonian, and to all except the lowest Burdigalian and the lower Helvetian, respectively. Hemingfordian-Barstovian implies a Lower to Middle Miocene age.

References. See Item 25 I. B. M. Funnell

(~$x) Jarbridge rhyolite, basal phase M. Miocene/M. Miocene North of Wildhorse, Nevada, U.S.A.

Radiometric age K-Ar (~# = 4"72 X Io-l°year-1; ;h = 0'585 × zo-X°year-X) Sarfidine KA I38O: K = 8"586%, arm. 4°Ar = 3%, age: I5"4bm.y. (Evernden et al. I964, pp. 164, x94).

Stratigraphical age. Barstovian; Rizzi Ranch fauna (Evernden et aL z 964, pp. I64, x94).

Reference EWRNV~N, J. F. et al. x964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 276. B. M. Funnell

(282) Miocene pumlclte M. Mioeene/M. Miocene Massacre Lake, east side of Long Valley, near Vya, Nevada, U.S.A.; z ft above mammal- bearing tuff.

Radiometric age K-Ar (~/~ = 4"72 × zo-Z°year-1; ;h = 0"585 × Io-l°year -1) Sanidine KA IOZ7: K = 4"72%; arm. 4°At = lO%. age 15"6bm.y. (Evernden et aL I964, pp. z64, 189).

Stratigraphical age. ? Early Barstovian; Massacre Lake fauna (Evernden et aL z 964, pp. 164, 189).

Reference EWRlVDSN, J. F. et al. z964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 276. B. M. Funnell

(283) John Day Form~tlon L. Miocene/L. Miocene Approx. I55oft above the base. Approx. 6miles north-west of Mitchell, Oregon, U.S.A. 419 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometric age K-Ar ()1# = 4"72 × IO-a°year-X; ~ = 0"585 × IO-t°Ye ar-1) K-albite ~ 649A: K ---- 1-43%, atm. *OAr = 7o%, age 24"9bm.y. (Evernden et al. I964, pP. I65, ~8l).

Stratigraphical age. Arikareean; John Day fauna (Evernden et al. I964, pp. x65, x8t).

References EVERNDVN, J. F. et al. I964 (see Item 27). WOOD, H. E. et al. I94! (see Item 26). lB. M. Funnell]

Stratigraphical comment. Thenius (1959, P. 288) regarded the Arikareean as equivalent to the upper Aquitanian and lower Burdigalian; Durham, Jahns & Savage (I954, fig. 2) regarded it as equivalent to the Aquitanian and lowest Burdigalian. Arikareean implies a Lower Miocene age.

References. See Item 246. B. M. Funnell

(284) Ignlmbrlte, John Day Format/on L. Miocene/L. Miocene Ignimbrite I IOO to 1135ft above base of John Day Formation, commonly regarded as separating middle and upper members of the formation; approx. 7 miles north-west of Mitchell, Oregon, U.S.A.

Radiometric age K-Ar (2# = 4"72 × Io-l°year-a; 2e = o'585 × xo-X°year-X) Obsidian lapilli KA 648: K = 4"5I%, atm. 4°Ar = 58%, age: 25"3bm.y. (Evernden et al. I964, pp. I65, I8I).

Stratigraphical age. Early-Late Arikareean; John Day fauna (Evernden et al. I964, pp. I65, i8i).

References. See Item 283 . [B. M. Funnell]

Stratigraphical comment. See Item 283. B. M. Funnell

(285) Black ash, C~rlng Formation L. Miocene/L. Miocene Ash I I ft above base of Gering Formation, north face of Scott's Bluff National Monument, Scott's Bluff County, Nebraska, U.S.A.

Radiometric age K-At (~'.a = 4"72 × xo-a°year-1; ~ = 0"585 X xo-a°year -1) Volcanic ash ~ 985: K = 2.66%, atm. 4°Ar = 66%, age: 25-6bm.y. (Evernden et al. I964, pp. I54 , I65, 186).

Stratigraphical age. Earliest Arikareean (Evernden et al. I964, p. I86). 420 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

References COOK, H.J. 196o (see Item 256). EVERZ~mEN,J. F. et al. I964 (see Item 27). WOOD, H. E. et al. I94Z (see Item 26). lB. M. Funnell]

Stratigraphical comment. See Item 283. B. M. Funnell

(286) Volcanic ash, fierlag Fonaatlon L. Miocene/L. Miocene Ash 2ft above Gering-Whitney contact, Morrill County, Nebraska, U.S.A.

Radiometric age K-Ar (2B = 4"72 × IO-l°year-Z; 1re = 0"585 X xo-l°year-X) Volcanic ash gA 98z: K = 5.04%, atm. 4°At = 36%, age: 29"5bm.y. (Evernden et al. 1964, p. i86).

Stratigraphical age. See Item 285.

Radiometric comment. 'May be somewhat contaminated as apparently 3.8m.y. older than ga 985' (Item 285) , which is only 9ft higher stratigraphically (Evernden et al. I964, pp. z54, I86).

References. See Item 285. lB. M. Funnell]

Stratigraphical comment. See Item 283. B.M. Funnell

(287) Brlte ignlmbrlte ~/L. Oligocene Vieja Group, south slope of Capote Mountain, Rim Rock country, Presidio County, Texas, U.S.A.

Radiometric age K-Ar (2p = 4"72 × zo-a°year-1; 2e = 0"585 × xo-l°year-a) Feldspar ~ Iooo: K = 4"6I% atm. ~°Ar = 5%, age: 29"7bm.y. (Evernden et aL z964, pp. x65, I87).

Stratigraphical age. Late Chadronian or younger; overlies Chadronian mammal fauna (Evernden et al. I964, p. z87). nefeTences DEFoRD, R. K. I958 (see Item 84). EV~RND~N, J. F. et al. z964 (see Item 27). STOVALL, J. W. x948 (see Item 84). [B. M. Funndl]

Stratigraphical comment. Thenius (z 959, P- 288) regarded the Chadronian as equivalent to the upper Lattorfian; Durham, Jahns & Savage (z954, fig. 2) regarded it as equivalent to the Tongrian. Chadronian implies a Lower Oligocene age, Late Chadronian or younger, a Lower Oligocene or later age.

References. See Item 246 . B. M. Funnell 421 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

(288) Interbedded tufts, John Day Formation Oligocene/Oligocene Tufts 165 ft above base of John Day Formation with Bridge Creek flora well developed above and below; Wheeler County, central Oregon, U.S.A.

Radiometric age K-Ar (2p = 4"72 × Io-l°year-X; 2e = 0"585 X IO-l°year-1) Sanidine KA 489: K = 4"47%, atm. 4°Ar = 54%, age: 3 I. xbm.y. (Evernden et aI. I964, pp. I65, x78).

Stratigraphical age. Chadronian-Whitneyan; Bridge Creek flora (Evernden et al. x964, pp. 165, 178).

References CHANEY, R. W. 1927- Geology and paleontology of the Crooked River basin, with special reference to the Bridge Creek flora. Publ. Carneg. Instn 346, 45-I38. EVERNDEN, J. F. et al. x964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. Thenius (x959, p. 288) regarded the Whitneyan as equivalent to the upper Stampian and Lower Aquitanian, and the Chadronian as equivalent to the upper Lattorfian. Durham, Jahns & Savage (1954, fig. 2) regarded them as equivalent to the Chattian and Tongrian, respectively. Chadronian-Whitneyan implies a Lower-Upper Oligocene, possibly lowest Miocene, age.

References. See Item 246. B. M. Funnell

(a89) Trachybasalt, John Day Formation L.-U. Oligocene/L.-U. Oligocene Lava 1 i5ft above base of John Day Formation (5oft below Item 288) ; 6 to 8miles north-west of Mitchell, Oregon, U.S.A.

Radiometric age K-Ar (2# = 4"72 × IO-x°year-1; 2e = o'585 × xo-X°year -x) Basalt, whole-rock KA 845: K = I "2o%, atm. a°Ar = 55%, age: 31 "5bm.y. (Evernden et al. I964, pp. I65, I84).

Stratigraphical age. Chadronian-Whitneyan (see Item 288) (Evernden et al. I964, pp. x65, 184).

References. See Item 288. [B. M. Funnell]

Stratigraphical comment. See Item 288. B. M. Funnell

(29o) Bracks rhyolite welded tuff L. Oligocene/L. Oligocene Bracks Formation, Vieja Series; Bracks Canyon, near foot of Gettysburg Peak, approx. 25miles west of Valentine, Presidio County, Texas, U.S.A. 422 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Radiometric age K-At (;tp = 4"72 × xo-X°year-X; ~ = o'585 x Io-X°year-X) Feldspar yo, xozo: K = 5.o3%, atm. 4°Ar = 4%, age: 36"8bm.y. (Evernden et al. x964, pp. x65, I88).

Stratigraphical age. Early Chadronian (Evernden et al. z964, p. I88).

References. See Item 287. [B. M. Funnell]

Stratigraphical comment. Thertius (I959, p. 288) regarded the Chadronian as equivalent to the upper Lattorfian; Durham, Jahns & Savage (I954, fig. 2) regarded it as equivalent to the Tongrian. Chadronian implies a Lower Oligocene age.

References. See Item 246. B. M. Funnell

(29x) Lone Tree Gulch Ash B L. Oligocene/L. Oligocene Natrona County, Wyoming, U.S.A.

Radiometric age K-Ar (2 B = 4"72 × ×o-×°year-I; 2e = 0"585 × Io-l°year -a) Sanidine (7o%), plagioclase (30%) ~ 895: K = 3"58%, atm. *OAr = 7%, age: 35"2bm.y. (Evernden et al. I964, pp. I85, I9o).

Stratigraphical age. Early Chadronian (Evernden et al. z 964, P. 185).

Reference EVrRNDEN, J. F. et al. I964 (see Item 27). [B. M. Funnell]

Stratigraphkal comment. See Item 29 o. B. M. Funnell

(292) Lone Tree Gulch Ash B L. Oligocene/L. Oligocene Natrona County, Wyoming, U.S.A.

Radiometric age K-Ar (2B -----4"72 × zo-l°year-1; ;re = 0"585 × IO-l°year -1) Biotite, with some hornblende, g_~ 897: K : 5"44%, atm. 4°At = 77%, age: 33"3bm.y. (Evernden et al. x964, p. I85)

Stratigraphical age. Early Chadronian (Evernden et al. I964, p. I85).

Reference EVERNDEN, J. F. et al. x964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 29 o. B. M. Funnell

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/tems

(293) Lone Tree Gulch Ash F L. Oligocene/L. Oligocene Natrona County, Wyoming, U.S.A.

Radiometric age K-At (/tp = 4"72 × xo-l°year-1;/re -~ 0'585 × xo-X°year-x) Biotite ~ 899: K = 6"65%, arm. 4°Ar = 4'%, age: 33"7 b m.y. (Evernden et al. ,964, pp. t85, '90).

Stratigraph{cal age. Middle Chadronian (Evernden et al. ,964, p. , 85). R~ EV~.RND~.N, J. F. et M. ,964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 290. B. M. Funnell

(294) Lone Tree Gulch Ash F L. Oligocene/L. Oligocene Natrona County, Wyoming, U.S.A.

Radiometric age K-Ar (,~p = 4"72 × IO-l°year-1; he-~ 0"585 × IO-x°yeax-l) Sanidine (8o%), plagloclase (2o%) ~ 9oo: K = 4.3I%, atm. 4°Ar = 6%, age: 35"7 b m.y. (Evernden et al. 1964, p. t 85).

Stratigraphical age. Middle Chadronian (Evernden et al. 1964, p. 185). Rcferenc# EVERNDEN, J. F. et al. x964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 290. B. M. Funnell

(295) Lone Tree Gulch Ash G L. Oligocene/L. Oligocene Natrona County, Wyoming, U.S.A.

Radiometric age K-Ar ()~p = 4"72 × to-l°year-t; 3~ = 0.585 × Io-X°year-1) Biotite ~ 898: K = 6.93%, atm. 4°Ar = 3x%, age: 32"6bm.y. (Evernden et al. I964, pp. I85, I9o).

Stratigraphical age. Middle Chadronian (Evernden et al. I964, p. x85).

Reference EWSRND~N, J. F. et al. x964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 29 o. B. M. Funnell

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Items

(~,96) Lone Tree Gulch Ash J L. Oligocene/L Oligocene Natrona County, Wyoming, U.S.A.

Radiometric age K-Ar (~B = 4"72 × Io-X°year-X; he = o'585 × IO-x°year-~) Biotite ga io32: K = 6"77%, atm. ~°Ar -- 28%, age: 3 x'6 b m.y. (Evernden et al. I964, pp. I65, I9o).

Stratigraphical age. Late Chadronian (Evernden et al. I964, pp. I65, I9o).

Reference EVEgND~N, J. F. et aI. x964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 290. B. M. Funnell

(297) Welded tufts, Wlndous Butte Oligocene/Oligocene West of Ely, Nevada, U.S.A.

Radiometric age K-Ar (21/= 4"72 × Io-X°year-X; 2e = 0"585 × Io-~°year -x) Biotite KA I45: K = 6"I%, arm. 4°At = 29% , age: 32-8bm.y. (Evernden et al. x964, pp. I65, I75).

Stratigraphical age. Fresh-water molluscs indicate Oligocene age (Evernden et al. I964, p. I75 ).

Reference EVERgreEN, J. F. et al. i964 (see Item 27). [B. M. Funnell]

(298) Pyroxene-madeslte, C~rno Formation uppermost Eocene-L. Oligocene/ uppermost Eocene-L. Oligocene From xoo-ft lava-flow, about Iooft above base of the 4oo-ft series of flows forming the uppermost Clarno Formation; 6 to 8miles north-west of Mitchell, Oregon, U.S.A.

Radiometric age K-Ar (2p = 4"72 × xo-a°year-a; /re = 0"585 × IO-l°year -x) Pyroxene-andesite gA 818: K = o'972%, arm. 4°At = 54%, age: 37.5 b m.y. (Evernden et al. I964, pp. i65, x82).

Stratigraphical age. Early Chadronian or late Duehesnean (Evernden et al. I964, pp. I65, I82). R~j~Tg?/ge EWRNDEN, J. F. a al. x964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. Therfius (1959, P. 288) regarded the Chadronian as equivalent to the upper Lattorfian, and the Duchesnean as equivalent to the Wemmelian and lower Lattorfian. Durham, 425 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Bems

Jahns & Savage (I954, fig. 2) regarded them as equivalent to the Tongrian and Ludian respectively. Early Chadronian or late Duchesnean implies lowest Oligocene or uppermost Eocene, probably the former.

References. See Item 246. B. M. Funnell

(299) Bentonitic claystone uppermost Eocene-L. Oligocene/uppermost Eocene-L. Oligocene Crystal-rich bentonitic claystone 2oft thick (underlying pyroxene-andesite of Item 298), 6 to 8miles north-west of Mitchell, Oregon, U.S.A.

Radiometric age K-Ar (itp = 4"72 × Io-t°year-X; ite = o'585 × xo-X°year -1) Sanidine KA 824A: K = 4"59 -4- o-x5% , atm. 4°Ar = I4%, age: 36.5 b -4- o'9m.y. (Evernden et al. I964, pp. x65, x82).

Stratigraphical age. Early Chadronian or late Duchesnean (see Item 298 ) (Evernden et al. I964, pp. I65, x82).

Reference EVERNDEN, J. F. et al. t964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. See Item 298. B. M. Funnell

(3oo) Sanldlne..biotite rhyolitic welded tuff, ha Norwood tuff U. Eocene-L. Oligocene/ U. Eocene-L. Oligocene Outcrop I mile north of Porterville, Morgan County, Utah, U.S.A.

Radiometric age K-Ar (it# = 4"72 × Io-l°year-1; it, = 0.585 × io-aOyear-X)

K (%) atm. 4°Ar (%) Age (m.y.) Sanidine KA825 8"I 3 54 37 "4b Biotite KA 826 5" 54 74 37"5 b Glass KA 827 4' 78 I9 36"o b

(Evernden et al. I964, pp. I65, 182-3)

Stratigraphical age. Duchesnean (Evernden et al. I964, p. I83).

References EARDLEY, A. J. i944. Geology of the north-central Wasatch Mountains, Utah. Bull. geol. Soc. Amer. 55, 8 x9--94. EV~RNDEN, J. F. et al. I964 (see Item 27). lB. M. Funnell]

Stratigraphical comment. Thenius (1959, p. 288) regarded the Duchesnean as equivalent to the 426 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/terns

Wemmelian and Lower Lattorfian; Durham, Jahns & Savage (I954~ fig. 2) regarded it as equivalent to the Ludian. Duchesnean implies an Upper Eocene to Lower Oligocene age.

References. See Item 246. B. M. Funnell

(3ox) Alamo Creek Basalt Member Upper Eocene]Middle Eocene Lowest flow in the Chisos Volcanic Formation; Big Bend National Park, Texas, U.S.A.

Radiometric age K-At (A/~ = 4"72 × ao-l°year-X; 2e = 0"585 × Io-X°year-1) Plagioclase KA 1274: K = I .416%, atm. 4°At ---= 14% , age: 42.7bm.y. (Evernden et al. 1964, pp. I65, I93).

Stratigraphical age. Probably Uintan; underlain by Bridgerian, overlain by probable Uintan (Evernden et al. 1964, p. I93 ).

Reference EVERNDEN,J. F. et al. 1964 (see Item 27). [B. M. Funnell]

Stratigraphical comment. Thenlus (I959, p. 288) regarded the Uintan as equivalent to the Ledian and lower Wemmelian, and the Bridgerian as equivalent to the upper Ypresian and Lutetian. Durham, Jahns & Savage (1954, fig. 2) regarded them as equivalent to the Bartonian, and the Lutetian and Auversian, respectively. Uintan implies a probable Upper Eocene age.

References. See Item 246 . B. M. Funnell

(3o2) Andesltie tuff sequence Upper Eocene/Upper Eocene (Tt on OM I24); Wyoming, U.S.A.

Radiomaric age K-At (~# = 4"72 × lO-l°year-1; he = 0'585 × IO-l°year-1) Biotite KA IO24: K = 6.45%, atm. 4°Ar = 7o%, age: 45-obm.y. (Evernden et al. I964, pp. 165, I89).

Stratigraphical age. Uintan (Evernden et al. I964, p. I89).

References EWRNDEN, J. F. et al. I964 (see Item 27). TOURTELOT, I-'I. A. 1953. Geology of the Badwater area, central Wyoming. U.S. Geological Survey Oil and Gas Investigation map OM 124. [B. M. Funnell]

Stratigraphieal comment. Thenius (I959, p. 288) regarded the Uintan as equivalent to the Ledian and lower Wemmelian; Durham, Jahns & Savage regarded it as equivalent to the Bartonlan. Uintan implies an Upper Eocene age.

References. See Item 246. B.M. Funnell

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hems

(3o3) Tuff, Wagonbed Springs M.-U. Eocene/M.-U. Eocene Tuff, 60 to 8oft below top of unit 3, cross-section 26 of Van Houten on OM I I3; one mile north of Wagonbed Springs, Wyoming, U.S.A.

Radiometric age K-Ar (2B -----4.72 × IO-l°year-1; ~----0.585 × Io-l°year-1) Biotite ~ Iox8: K ---- 6.9o%, atm. 4°Ar ----- 6%, age: = 45"4bm.y. (Evernden et al. I964, pp. x65, i89).

Stratigraphical age. Late Bridgerian or Early Uintan (Evernden et al. x964, pp. I65, I89).

References EWRNDEN, J. F. et al. I964 (see Item 27). VAN HotrrEN, F. B. I95o. Geology of the western part of Beaver Divide area, Fremont County, Wyoming. U.S. Geological Survey Oil and Gas Investigation map oM ,x 3. I954. Geology of the Long Creek-Beaver Divide area, Fremont County, Wyoming. U.S. Geological Survey Oil and Gas Investigation map OM x40. lB. M. Funnell]

Stratigraphical comment. See Item 3oi, except that the Late Bridgerian or Early Uintan implies a late Middle Eocene or early Upper Eocene age. B. M. Funnell

(3o4) Bentonltle ash, Green Clove L.-M. Eocene/L.-M. Eocene Bentonitic ash, upper part of blue ledge marker, in unit I of stratigraphical section 7 of Van Houten; Green Cove, Wyoming, U.S.A.

Radiometric age K-Ar (/tB ----4.72 × io-10year-X; ~e = 0"585 × Io-l°Year-1) Biotite ~ Io2x: K ---- 6.62%, atm. 4°Ar ---- 22%, age: 49-obm.y. (Evernden et al. I964, pp. I65, 189).

Stratigraphical age. Late Wasatchian or Early Bridgerian (Evernden et al. I964, pp. x65, I89).

References. See Item 246. [B. M. Funnell]

Stratigraphical comment. Thenius (x 959, P- 288) regarded the Bridgerian as equivalent to the upper Ypresian and Lutetian, and the Wasatchian as equivalent to the Sparnacian and lower Ypresian. Durham, Jahns & Savage (I954, fig. 2) regarded them as equivalent to the Lutetian-Auversian and the Sparnacian-Ypresian-Culsian respectively. Late Wasatchian or early Bridgerian implies a Lower Eocene or early Middle Eocene age.

References. See Item 246 . B. M. Funnell

(305) Tuff, Wind River Formation L. Eocene/L. Eocene In Beaver Creek oil and gas field, approx. 13 miles south of Riverton, Wind River Basin, Wyom- ing, U.S.A. 428 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

/tems

Radiometric age K-Ar (2/t = 4"72 × Io-t°year-1; 2e = o'585 × IO-t°year-1) Biotite KA IOI2: K = 4"57%, atm. a°Ar = 56%, age: 49"2bm.y. (Evernden et al. I964, pp. I65, I88).

Stratigraphical age. Late Wasatchian (Evernden et al. x964, pp. 165, 188).

Referetlge$ EVERNDEN, J. F. et al. 1964 (see Item 27). HAY, R. L. I956. Pitchfork formation, detrital facies of early basic breccia, Absaroka Range, Wyoming. Bull. Amer. Ass. Petrol. Geol. 40, I863--98. StNCLAIR, W. J. & GgANGZR, W. 191 I. Eocene and Oligocene of the Wind River and Big Horn basins. Bull. Amer. Mus. nat. Hist. 3 o, 83-I 17. TrIOMPSON, R. M. & WHIT% V. L. 1954. Geology of the Riverton area, central Wyoming. U.S. Geological Survey Oil and Gas Investigation map OM 127. [B. M. Funnell]

Stratigraphical comment. Thenius (I959, p. 288) regarded the Wasatchian as equivalent to the Sparnacian and lower Ypresian; Durham, Jahns & Savage regarded it as equivalent to the Sparnacian-Ypresian-Cuisian. Wasatchian implies a Lower Eocene age.

References. See Item 246. B. M. Funnell

(3o6) Porphyritic basalt, South Table Motmtaln post-early Palaeocene/ post-early Palaeocene Approx. 235ft stratigraphically above Item 307 and Puercan fossil-bearing bed, Denver Forma- tion; South Table Mountain, in Denver Basin, near Golden, Colorado, U.S.A.

Radiometric age K-Ar (2p = 4"72 × xo-l°year-1; 2e = 0"585 x Io-l°year -l) Porphyritic basalt KA 978: K = 3"7I%, arm. 4°Ar ---- 3%, age: 58"7bm.y. (Evernden et al. 1964, Pp. x65, 186).

Stratigraphical age. Post-early Puercan (Evernden et aL I964, p. 186).

Reference£ EVERND~N, J. F. et al. 1964 (see Item 27). Gnzis, C. L. 1941. Paleocene mammals from the Denver Basin, Colorado. 07. Wash. Acad. Sci. 31 (7), 289-95. [B. M. Funnell]

Stratigraphical comment. Thenius (I959, p. 288) regarded the Puercan as possibly equivalent to the Montian; Durham, Jahns & Savage (I954, fig. 2) regarded it as equivalent to the lower Montian. Puercan implies a Lower Palaeocene age.

References. See Item 246. B. M. Funnell

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Items

(3o7) Pumice, South Table Mountain L. Palaeocene/L. Palaeocene Cobbles of dacitic pumice, approx. 35ft stratigraphically above Cretaceous-Tertiary boundary and 235ft below Item 3o6, Denver Formation; South Table Mountain, in Denver Basin, near Golden, Colorado, U.S.A.

Radiometric age K-Ar (2# -----4" 72 × Io-l°year-1; ~ = o'585 x Io-l°year -1) Plagioclase KA 992: K = 6.o3% , atm. 4°Ar = 39%, age: 64.8bm.y. (Evernden et al. I964, pp. x65, I68, 187).

Stratigraphical age. Puercan; South Table Mountain fauna and Denver flora (Evernden et al. 1964, pp. 165, 168, 187).

References. See Item 306. [B. M. Funnell]

Stratigraphical comment. See Item 306. B. M. Funnell

(308) Ash, Glenns Ferry Formation Plio-Pleistocene/Plio-Pleistocene About 9oft below the lava-flow of Item 250 , Glenns Ferry Formation; Hagerman 7½ quadrangle, Twin Falls County, Idaho, U.S.A.

Radiometric age K-Ar (2# = 4"72 × IO-t°year-t; 2e ~---0"585 × Io-l°year-t) Ash KA 83I: K = 3"82%, atm. *OAr = 77%, age: 3.3bm.y. (Evernden et al. I964, p. I84).

Stratigraphical age. Blancan; Hagerman fauna (Evernden et al. x964, p. 184).

References. See Item 25o. [B. M. Funnell]

Stratigraphical comment. See Item 250. B. M. Funnell

(3o9) Ash, Glenns Ferry Formation Plio-Pleistocene/Plio-Pleistocene About 9oft above the lava-flow of Item 250 , Glenns Ferry Formation; Pasadena Valley quadrangle, Twin Falls County, Idaho, U.S.A.

Radiometric age K-Ar (~a = 4"72 × io-t°year-X; ~ = 0"585 × IO-x°year-x) Ash KA 832: K = 3"2o%, arm. *°Ar = 8I%, age: 3.2bm.y. (Evernden et al. I964, p. I84).

Stratigraphical age. Blancan (Evernden et al. 1964, p. 184).

References. See Item 25 o. [B. M. Funnell]

Stratigraphical comment. See Item 250. B. M. Furmell

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//eros

(3zo) Tuff, Santa Cruz Formation L. Miocene/L. Miocene Santa Cruz, Rio Gallegos, Patagonia, Argentina.

Radiometric age

K-Ar (hB = 4"72 × IO-l°year-1; he : 0"585 × Io-l°year -1) Plagioclase KA I252: K = o-I796%, atm. 4°Ar = 88%, age: 2x "7bm.y. (Evernden et al. x964, p. I92).

Stratigraphical age. Santacrucian, correlated with the Burdigalian of Europe (Evernden et al. x964, pp. I7O, x92).

References EVERm~EN, J. F. et al. x964 (see Item 27). KELLOGO, R. 1934. The Patagonian fossil whalebone whale, Cetotherium moreni (Lydekker). Publ. Carneg. Instn, 447, 65-8I. SIMPSON, G. C. x94o. Review of the mammal-bearing Tertiary of South America. Proc. Amer. phil. Soc. 83, 649-709. lB. M. FunneU]

(3xI) Basalt, Hsanda Gol Formation, Mongolia L. Oligocene/L. Oligocene

Radiometric age K-At (hp : 4"72 × xo-X°year-a; he = 0"585 × Io-l°year -1)

Basalt, whole-rock arm. K (%) '°At% Age (m.y.) vo. z277 o. i886 64 32"o b KA I277 R o. x886 53 3 I'3 b (Evernden et al. 1964, p. 193)

Stratigraphical age. Early Oligocene (Evernden et al. x964, pp. x7o, I93).

References EVERNDEN, J. F. et al. I964 (seeltem 27). MATTrmW, W. D. & GRAN6ER, W. x923. New Bathyergidae from the Oligocene of Mongolia. Amer. Mus. aVovit, xox, i- 5. x924. New Insectivores and Ruminants from the Tertiary of Mongolia, with remarks on the correlation. Amer. Mus. aVovit, xo5, z-7. [B. M. Funnell]

(3x2-3x8) [Miscellaneous: Kenya, New Guinea, U.S.A.] Miocene-Pliocene (312) Kiahera Series, Rusinga Island, Lake Victoria, Kenya; early Miocene-early Pliocene; x4-6b-+- 1.4 to I5"9b -4- 1.5m.y. (also 22.2 b to I67bm.y.: invalid determinations) (Evernden et al. 1964, pp. x76, x8i, gat 336, 336R, 656, 800, 8OZ, 802) [biostratigraphical control unsatisfactory].

(3z3) Fort Ternan anthropoid site, Kenya; Lower Pliocene; I4.obm.y. (Evernden et al. I964, p. x76, KA 427) [biostratigraphical control unsatisfactory]. 43 x Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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(3x4) Kapiti phonolite, Stoney Athi River, Kenya; earliest Late Cainozoic volcanism, pre-dating rift-faulting; x3 .4bm.y. (Evernden et al. I964, p. ISx, KA 65 t) [biostratigraphical control lacking].

(3x5) Merriam's Middle Member, 835ft above base of John Day Formation, I2 miles north- north-west of Mitchell, Oregon, U.S.A.; Early Arikareean [Lower Miocene]; 23-3bm.y. (Evernden et al. x964, pp. I8o-i, g.A 647 A) [radiometric age too young: el. Items x97, 283, 284].

(3x6) Gering Formation, Morrill County, Nebraska, U.S.A.; earliest Arikareean [Lower Mio- cene]; 46bm.y. (radiometric age invalidated by contamination) (Evernden et al. I964, pp. x54, x86, KA 979)-

(3x7) Bald Peak basalts, Bald Peak, Berkeley Hills, California, U.S.A. ; latest Clarendonian or early Hemphillian [Upper Miocene]; 7.7bm.y. (radiometric age only a minimum figure) (Evernden et al. I964, pp. x55 , I88, g~, xoo3) [no upper stratigraphical control].

(3x8) Otibanda Formation, Lower Watut basin, New Guinea; 'Sunshine' fauna (Pontian); 6. xb and 7.6bm.y. (Evernden et al. x964, pp. i7 o, I92- 3, KA I26O, I257 ) [biostratigraphical relationships not certain].

Rgf~t-olge EVERNDEN, J. F. et al. I964 (see Item 27). [B. M. Funnell]

(3x9) Lep|doHte from pegm2tlte Cretaceous/Cretaceous Pala Mine, south California, U.S.A.

Radiometric age (I) K-Ar (it~ = 4"72 × IO-x°year-X; ite = 0"585 × xo-X°year-X) Lepidofite: 4°K = to. 5 ppm, 4°Ar* = o.o56o ppm, 4°Ar*/total4°Ar = o.86, 4°Ar*#°K = [0"00533].

Age: 89 m.y. (Aldrich et al. x958, p. i t3o). (2) Rb--Sr (t t = 5.o × xol0year) Age (m.y.) (i) Rb (%) a'Sr* (ppm) S~Sr*/STRb it = 1.39 it = x "47 r.74t 1.752~ 6-9 [o'oox4o ] Ioo [95] I'77t I "7o~: 7"o [0"00142] Io4 [97] ~" determined by neutron activation. ~: determined by isotope dilution. (Webster, Morgan & Smales I957) (ii) (it = 1.39 × xo-l°year -x) STRb = 4980 ppm, 878r* ---~ 7"38 ppm, sTSr*/total sTSr ---- 0. 98, sTSr*/STRb = [o.oox48 ].

Age: io6m.y. (it = 1.39 ) (Aldrich etal., p. ii3o); [xox]m.y. (2 = x'47 ). Holmes (I959) uses 96m.y. (2, i) and ioom.y. (2, ii).

Stratigraphical age. Middle or early Upper Cretaceous.

References ALDRXCH, L. T. et al. I958 (see Item x86). 432 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items HOLMES, A. I959. WEBSanS~, R. K., MORGAN,J. W. & SMALES, A. A. I957. Some recent Harwell analytical work on geochronology. Trans. Amer. geophys. Un. 38, (4), 543 -6. [R. Casey]

(320) Schist Cretaceous/?Triassic Q uartz-albite-clinozoisite-chlorite-muscovite schist, Haast-Makarora road, at Clarke Bluff, Westland, South Island, New Zealand.

Radiometric age K-Ar (constants not known) Biotite: K = 8.o1%, 4°Ar*/4°K = o'oo46, age: 76 [77] m.y.

Stratigraphical age. ? Lower Cretaceous (see stratigraphical comment).

Radiometric comment. Mason interprets the low age as reflecting argon loss during deep burial. JR. Casey] References HURLEY, P. M. et al. I96O. Variations in isotopic abundances of strontium, calcium and argon, and related topics. Department of Geology and Geophysics, Massachusetts Institute of Technology. Eighth Annual Progress Report for 19~ , pp. 255- 7. MASON, B. 1961. Potassium-argon ages of metamorphic rocks and granites from Westland, New Zealand. N.~. 07. Geol. Geophys. 4, 352-6.

Stratigraphical comment. According to Mason the geological evidence for the age of the metamorphism is controversial. Two views are held: (i) the schists are Palaeozoic rocks metamorphosed in a we-Triassic orogeny; (ii) the schists are Triassic (and possibly older) sedimentary rocks metamorphosed in an early Cretaceous orogeny. The crux of the argument depends on whether the fossiliferous Triassic rocks in the southern Alps grade continuously into the schists or are separated from them by an unconformity (not observed in the field). Low-grade schist pebbles are common in Cretaceous conglomerates. [A. G. Smith]

(3at) Core samples of igneous rocks U. Palaeocene/U. Jurassic South-western part of Verkhoyano-Kolyma fold-belt, north-eastern U.S.S.R.

Radiometric and stratigraphical ages (abstract only available). K-Ar determinations on 65 igneous rock samples gave ages ranging from 16o a to 64 a m.y. Igneous activity was almost continuous, punctuated with short intervals of quiescence. The oldest rocks analysed, granodiorites of the Pravo--Arangassk massif, give ages of I4oa to x6oam.y. (Upper Jurassic). The next period of igneous activity occurred during the Lower Cretaceous and is dated at I30a to I2oam.y. A third period occurred at IOOa to 9oam.y., also Cretaceous.

Reference NENASI-mV, N. I. 1962. [The time of formation of the igneous rocks in the 'longitudinal' and 'transverse' zones of the western part of the Verkhoyano-Kolyma folded region.] Trudi Sessii Ifomissii po Oprededeniyu absolyutnogo Vozrasta Geologicheskikh Formatsii, to, 252-67 [in Russian. Abstract in Referat. ~hyrnal. I963, (9), B. 83]. [R. Casey]

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Stratigraphical comment. The palaeontological evidence for dating the stratigraphical intervals is not stated in the abstract. R. Casey

1" (322) Egorev deposit L. Cretaceous/U. Jurassic Moscow region, U.S.S.R.

Radiometric age K-Ar (2p = 4"72 × xo-l°year-1; Jle = 0"557 × IO-x°year-1) K (%) '°Ar*/'°K Age (m.y.) (x) Glauconite 4.02 0"0072 I~5 [x 19] (2) Glauconite 5"23 0"0079 136 [x3x]

Stratigraphical age. (I) Lower Cretaceous ('Valanginian' [Ryazanian]) ; (2) Upper Jurassic (Upper Volgian).

References ANON, I960. [Geological scale of absolute age-determinations from laboratories in the U.S.S.R. for x96o.] Bull. Acad. Sci. U.R.S.S. x~io (Io), I7-2I [in Russian]. POLEVAYA, N. I. 196 I. [Materials for constructing a scale of absolute geochronology for the Cam- brian and onwards.] Trudi Sessi Komissii po Oprededeniyu Absolyutnogo Vozrasta Geologicheskikh Formatsii, xo, x7 I-2 x5 [in Russian]. [R. Casey]

Stratigraphical comment. The Egorev deposit, a condensed deposit rich in glauconite and phosphatic nodules, contains five distinct horizons. The lower four belong to the Upper Jurassic (Lower and Upper Volgian), the topmost belongs to the zone of Riasanites rjasnensis, i.e., basal Cretaceous (Ryazanian). [In current Russian classification the Ryazanian is included as part of the Valan- ginian.] There is evidence that the phosphorite seams have been reworked (Strakhov 196o).

RefeTgncg STP.AKHOV, N. M. x960. [Climate and phosphate accumulation.] Geologiya Rudnykh Mestorozhdenii (1), I3-I 5 [in Russian. English translation in Economic Geology U.S.S.R. x~3 (I-2), 1-I3]. [R. Casey]

(323) Kokhp granltold massif U. Cretaceous/Jurassic Armenia, U.S.S.R.

Radiometric age K-Ar: biotite (no further data given) ; age: x27a m.y. (but see below)

Stratigraphical age. Lower Cretaceous (post-Jurassic to pre-Cenomanian).

Reference ANON. X960 (see Item 322). t The Upper Jurassic determination may correspond to that in Item 72. 434 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Radiometric comment. Having regard to the decay constants in use in the U.S.S.R. in I96o, this result should be reassessed at, say, 12 t m.y. [R. Casey]

(324) Khahan granltoid massif ? U. Jurassic/L. Jurassic River Onon, Trambaikalia, U.S.S.R.

Radiometric age K-Ar (2B = 4"72 × Ioq°year-1; he = 0"557 × Ioq°Y ear-l) K (%) '°Ar*/'°K Age (m.y.) Biotite from granite ~( 7" 4 ° o- 0082 I4I [135] k. 6.65 o.oo76 I32 [I26] Muscovite from pegmatite 7"45 o.oo85 146 [14o]

Stratigraphical age. ? Upper Jurassic (post-Lower Jurassic).

References. See Item 322. [R. Casey]

(325) Olodonln and Durulgnev granitoid masslfs U. Jurassic/L. Jurassic Transbaikalia, U.S.S.R.

Radiometric age K-Ar (hp = 4"72 × IO-l°year-1; /~e = 0"557 × IO-I°Year-l) K (%) 40Ar*/40K Age (m.y.) (1) Biotite from granite, Olodin massif 6.16 o. 0085 146 [ 14o] (2) Muscovite from pegmatite, Durulguev massif 8-00 o. 0085 x46 [ 14o]

Stratigraphical age. The Olodonin granites intrude Lower Jurassic (Toarcian) strata. The Durulguev granites intrude Triassic rocks but are petrochemically similar to the Olodonin suite.

References. See Item 322. [R. Casey]

(326) Crimean igneous rocks ? U. Cretaceous/U. Jurassic Crimea, U.S.S.R.

Radiometric age K-Ar (hp = 4"68 x xoq°year-a; he = 0"585 × xo-X°year -1)

Rock and locality K (%) *0Ar*/40K Age (m.y.) Quartz-diorite, Ukrainka I- i2 0.00656 IO9 Microdiabase, Ukrainka o-68 o.oo65 ° IO8 Quartz-porphyry, Lower Sablov 2"x 4 0.00582 97 Diabase, Karagach o. 5 o.oo64o'),. IO6 o.oo615J ~ IO2 Keratophyre, Kara'Daga I'O o.oo664 IIO 435 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical age. ? Upper Cretaceous-Upper Jurassic. Reference FIRSOV, L. V. x963. [Absolute dating of the igneous rocks in the Crimea as possible key horizons for the Bajocian stage.] Bull Acad. Sci. U.R.S.S. x#3 (4), 24-34 [in Russian]. [R. Casey]

Stratigraphical comment. These results suggest the Aptian-Albian stage of the Lower Cretaceous. Firsov compares these results with Albian and Aptian glauconite dates obtained from the Caucasus and elsewhere. R. Casey

(327) Intrusive rocks with gold-ore deposits Cretaceous/Jurassic Yano-Kolyma region, north-eastern U.S.S.R.

Radiometric age K-Ar (hp = 4"68 × IO-l°year-1; he = o'585 × Io-l°year -1) Twenty-one intrusive igneous rock samples have been dated by whole-rock K-Ar methods. The ages fall into two groups: (a) for rocks intruded before gold-deposition (t28 to I34m.y.), and (b) for rocks intruded after gold-deposition (99 to I 13 m.y.).

Stratigraphical age. Lower Cretaceous.

Reference Fmsov, L. V. 196o. On the age of the gold mineralization in the Soviet north-east. Geolog#a Rudnykh Mestorozhdenii (2) 53--62 [in Russian. English translation in Economic Geology U.S.S.R. x963, (i-2), xo3-i4]. JR. Casey]

Stratigraphical comment. The paper by Firsov (x96o) reverses previous ideas on the supposed Upper Jurassic age of the gold deposits. No evidence is, however, given that the radiometrically dated intrusions are in contact with palaeontologically dated sediments. Apparently the intrusions are assigned to the Lower Cretaceous by reference to previously constructed time-scales. The oldest rocks ( 134 m.y.) are nearly of the same age as the oldest rocks of the Magadan b atholith ( 136 m.y. ; see Item 328), for which there is said to be independent evidence of Cretaceous age. R. Casey

(3~8) iagadan batholith Magadan, shore of the Okhotsk sea, north-eastern U.S.S.R.

Radiometric age K-Ar (ha ----4.68 × IO-x°year-1; ~ = 0.585 × Io-l°year -x) Twenty-eight intrusive igneous rocks and minerals have been dated by K-Ar methods. Ages range from 71 to 136 m.y.

Stratigraphical age. Cretaceous.

Reference FIRSOV, L. V. I96O. [Absolute age of the igneous rocks of the Magadan batholith.] Bull. Acad. Sci. U.R.S.S. x96o (2), 28-38 [in Russian]. [R. Casey] 436 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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Stratigraphical comment. In this part of the Pacific ore-belt, gold is associated with plutons emplaced principally or wholly in the Lower Cretaceous (during the Kolyma phase of folding [Nalivkin I96O; Firsov i96o ] ; see Item 327). In the Okhotsk region several hundred separate intrusive bodies form a belt of batholiths 2ooo km long. Many of these bodies metamorphose Jurassic and Lower Cretaceous sediments and volcanic rocks, and are overlapped by Upper Cretaceous volcanic rocks; some of the intrusions are in contact with deposits of Cenomanian-Senonian age. By analogy with the age of neighbouring batholiths, Demin (1946 , i949) concluded that the Magadan batholith was wholly Cretaceous in age. In this region, marine faunas with AuceUa (Nalivkin z96o ) permit palaeontological dating of Upper Jurassic and basal Lower Cretaceous rocks. The extent of palaeontological control for the age of the Magadan and other batholiths is not known to the abstractor, though Demin's conclusions seem to be borne out by the radiometric ages, which span the basal Ryazanian-high Senonian interval. Firsov regards the initial gabbro and gabbro-diorite phase (dated at i34m.y. ) as marking the Jurassic-Cretaceous boundary; the sample analysed came from a minor intrusion associated with the Magadan batholith.

Refere~e$ DEMIN, A. IV[. x946. [Stages in the formation of the Magadan batholith.] Mater. Geol. polezn. Iskop. (2) [in Russian]. -- 1949. [Morphology and tectonic elements of the Magadan batholith.] Mater. Geol. polezn. Iskop. (7) [in Russian]. FIRSOV, L. V. I96o (see Item 327). MATVEYENKO, V. T. • SHATALOV, E. T. 1963. Fractures, magmatism and mineralization in the north-east of the U.S.S.R. (Part I). Int. Geol. Rev. 5, 127-56. NALIVKIN, D. V. I960 (see Item 33). R. Casey

(329) Quart~porphyry tufts ? Palaeocene/U. Cretaceous Outcrops between Sikhote and Kuznetsovsk, Sikhote-Alin, Soviet Far East.

Radiometric age K-Ar (2p = 4.72 × lO-l°year-1; ite = o.557 × Io-X°year -x) K (%) 4°Ar*/4°K Age (m.y.) o.89 o. oo43 74 [72] 2.58 o. oo37 66 [62- 5] 2"96 o'oo37 67 [62"5] 2"96 o'oo38:~ 67 [64] :~ 2.4o o. oo4 x 7° [69] 2"4o o.oo4o:~ 7o [67"5]:~ 3" 8o o. oo36 66 [6o- 5] 3" 8o o. 0037 $ 66 [62.5] :~ Average age: [65" 5] m.y. :~ Data given in Polevaya & Izokh (x96o). The alternatives are given in Polevaya (1961) and are assumed to be more accurate. Only these have been used to calculate the average.

Stratigraphical age. Danian. The quartz-porphyry tufts are in contact with Lower to Upper Cre- taceous strata. At the base is a coaly lens containing plant-impressions believed to be of Danian age (Polevaya & Izokh t96o ). 437 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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References POLEVAYA, N. I. I96I (see Item 322). -- & IZOKH, E. P. 1960. [Absolute age of Upper Cretaceous and Tertiary effusive and intrusive rocks of northern Sikhota-Alin and the Mao-Chang mountain range.] Bull. Acad. Sci. U.R.S.S. ,~o, (7), 46-5 ° [in Russian]. JR. Casey]

Stratigraphical comment. As in the Monastir volcanic suite (Item 332) [with which Polevaya compares this series], it may be premature to accept palaeobotanical evidence as such a precise criterion of stratigraphical age. R. Casey

(33 o) Idaho bathoHth Miocene/? Jurassic Idaho, U.S.A.

Radiometric age Twenty-two Pb-~ determinations on zircon, monazite, thorite, and xenotime give ages ranging from 9 oa to x35 a m.y.

Stratigraphical age. Cretaceous.

Reference JAFFE, H. W. a al. x959 (see Item 2 x7)-

Stratigraphical comment. Granitic rocks of the Idaho batholith have been considered to range in age from Jurassic to Palaeocene (Ross I928 , p. 692 ; Anderson I952 , pp. 261-3) , but a Cretaceous or Lower Cretaceous age is now more generally accepted (Ross & Forrester x947; Larsen et aL x958 , p. 51; Arkell i956 , p. 552). The cover-rocks of the batholith include Miocene and (?) Pliocene basalts and Quaternary alluvium. Independent geological evidence of Cretaceous age for this batholith is not satisfactory.

Referertce$ ANDERSON, A. L. x952. Multiple emplacement of the Idaho batholith. 07. Geol. 6o, 255-65. ARKELL, W.J. i956 (see Item 75). LARS~, E. S., Jr, GOTTFRmD, D., JA~'E, H. W. & ~[ARINO, C. L. I958. Lead-alpha ages of the Mesozoic batholiths of western North America. Bull. U.S. geol. Surv XO70-B. Ross, C. P. I928. Mesozoic and Tertiary rocks in Idaho. 07. Geol. 36, 673-93. & FORRESTER, J. D. i947. Geologic map of the State of Idaho. Geological Survey and Idaho Bureau of Mines and Geology. R. Casey

Radiometric comment. See Item i89. A. G. Smith

(33 x) San Jose quartz-dlorlte U. Cretaceous/L. Cretaceous North-west corner of San Jose pluton, Baja California, Mexico.

Radiometric age Pb-~: zircon : I 12 a m.y. 438 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Stratigraphical age. 'Early late Cretaceous (post-Albian, pre-Maestrichtian)' (Silver, Stehli & Allen x956 ).

References JAFfa, H. W. et al. x959. (see Item 217). SILVER, L T., STEHLI, F. G. & ALLEN, C. R. x956. Lower Cretaceous pre-batholithic rocks of northern Baja California, Mexico. [Abstract]. Int. geol. Congr. 2o, Resumenes de los Trabados Presentados, p. 3 o.

Stratigraphical comment. The Albian age of the intruded rock is not satisfactorily established. R. Casey

Radiometric comment. See Item x89. A. G. Smith t (332) Monastlr volcanic suite Palaeocene/U. Cretaceous Olga-Tetyukhin region of southern Primorye, north-eastern U.S.S.R. Crystalline-clastic tuff of quartz-porphyries: (I) River Monastirka; (2) Pad Rossipnaya, quartz-porphyry; (3) River Sadaga.

Radiometric age K-Ar (2 B = 4"72 × Io-a°year-a; 2e = 0"557 × xo-l°year -t) K (%) 4°Ar*/4°K Age (m.y.) (I) 3"44 O'OO41 72 [69] (2) 3" I I O'OO40 70 [67" 5] (3) 3" 29 o. oo38 67 [64] Average age: 7 ° [66.5] m.y.

Stratigraphical age. Danian. The Monastir volcanic suite is overlain by the Palaeocene Siyanov suite, and rests on sedimentary rocks of the Arzamasov suite dated as Upper Senonian on palaeobotanical evidence.

RefereIl£g POLEVAYA, N. I. x96z (see Item 322). [R. Casey]

Stratigraphical comment. In conformity with Soviet practice, Polevaya includes the Danian stage in the Cretaceous System. The stratigraphical and palaeontological evidence for a Danian age- assignment for the Monastirsk volcanic suite is meagre. R. Casey

(333) Vladlmlr granites Palaeocene/U. Cretaceous Olga-Tetyukhin region of southern Primorye, north-eastern U.S.S.R.

Radiometric age K-Ar (,~# = 4"72 × Io-X°year-1; 2e = 0"557 × xo-t°year -1) t Some of these determinations may correspond to those listed in Items I39-45, but this cannot be ascertained from the literature available. 439 Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

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K (%) 4°Ar*#°K Age (m.y.) D. Betka 3" 34 o" 0039 69 [65" 5] River Sadaga 3" 68 o. oo42 74 [7°. 5] Cape Mramor 3" 33 o-oo36 64 [6o" 5] Tavaiza Mountain 2 "94 o .oo45 78 [75 "5] Vladimir Bay 2.3 ° o'oo41 72 [69] Vladimir Bay 2" 98 o. oo4 ° 7° [67" 5] Vladimir Bay 3" 55 o.oo37 66 [62.5] Olga Bay (granodiorite) 2" 75 o.oo41 72 [69] Olga Bay (granodiorite) I "93 o. oo39 69 [65-5] Average age: 7° [67" 5] m.y.

Stratigraphical age. Danian. The granites intrude the Kisin suite (Item 334), and are overlain by the Monastin volcanic suite (Item 332), also referred to the Danian.

Reference POLEVAYA, N. I. I96I (see Item 322). [R. Casey]

Stratigraphical comment. The evidence given by Polevaya (t96I) for the Danian age of the granites is inadequate. R. Casey

1"(334) I~s~a and Bazov vol~c suites Palaeocene]U. Cretaceous Olga-Tetyukhin region of southern Primorye, north-east U.S.S.R.

Radiometric age K-Ar (~ = 4"72 × Io-l°year-1; he = 0"557 × xo-X°year-a) K (%) 4°Ar*/4°K Age (m.y.) " quartz-porphyry 2" 60 o" o043 75 [72] (I) Kisin quartz-porphyry 2" 34 o.oo4o 7° [67" 5] suite quartz-porphyry 2.6o o" oo43 75 [72 ] t. crystalline-elastic tuff of quartz-porphyry 2" 9 ° o" oo44 77 [74] (2) Bazov suite porphyries ~ I. 24 o.oo43 75 [72 ] 1.43 o.oo48 83 [80.5] Average for quartz-porphyry: 74 [7o" 5]m.y. ; average for porphyries: 79 [76 "5]m.y.

Stratigraphical age. rUpper Cretaceous (Kisin suite: Senonian; Bazov suite: Lower Senonian or Turonian). The Kisin suite is overlain by the Arzamasov suite, determined as Danian by palaeobotany, and rests on the Bazov suite. The last overlies sedimentary rocks with an Albian- Cenomanian fauna. Rgfo-ozge POX~VAYA, N. I. I96I (see Item 322). [R. Casey]

Stratigraphical comment. The two species of oyster (Exogyra ex. gr. flabellata Gold. and E. el. localis t Some of these determinations may correspond to those listed in Items i39-45 , but this cannot be ascertained from the literature available. 44o Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Mordv. var. subtipica Mordv.) cited by Polevaya in her stratigraphical summary seem insufficient to establish the Albian-Cenomanian age of the pre-Basov sediments. R. Casey

(335) Gr~m_'told intrusions U. Cretaceous/L. Cretaceous (i) River Sukhaya; (2) Sudno Mountain; (3) Olga Bay; Olga-Tetyukhin region of southern Primorye, north-eastern U.S.S.R.

Radiometric age K-Ar (~'B = 4"72 × xo-l°year-X; ~-----0"557 × Io-l°year -1) K (%) '°Ar*/'°K Age (m.y.) (x) Granite 3" x2 o.oo52 91 [87] (2) Microgranite 4"ro o.oo56 99 [93"5] (3) Diorite I "27 0"0053 93 [88"5] Average age: 94 [9o] m.y.

Stratigraphical age. Upper Cretaceous (Cenomanian). This series is regarded as belonging to the first stage of Upper Cretaceous intrusive activity in southern Primorye (see Item 333). Intruded rocks are dated as Albian-Cenomanian.

Reference POLEVAYA, N. 1. x96I (see Item 322). [R. Casey]

Stratigraphical comment. See Item 334. R. Casey

(336) Volcanic-sedlmentary series, Bureln U. Cretaceous/L. Cretaceous River Badzhal, Burein region, Khabarov, Soviet Far East.

Radiometric age K-Ar (~t~ ---- 4" 72 × Io-l°year-1; ~e----0"557 × Io-l°year -a) Porphyritic dacite: K = 2-83% , 40Ar*/4°K = o.oo6o, age: Io 5 [Ioo]m.y.

Stratigraphical age. Uppermost Lower Cretaceous or lowermost Upper Cretaceous. The series is overlain by Upper Cretaceous volcanic rocks and rests on strata with a Lower Cretaceous flora. Palynology suggests that the series is Upper Cretaceous in age, though geological data favour the upper part of the Lower Cretaceous. The series was placed in the Albian by Polevaya (I96I) on palaeobotanical grounds. References Bmovsg_~yA, E. V. & POL~.VAYA, N. I. 196o [Absolute age of volcanic formations of the Badzhal and Burein Mountains.] Bull. Acad. Sci. U.R.S.S. z96o (xo), 86--9t [in Russian]. POL~VAYA, N. I. I96X (see Item 322). [R. Casey]

(337) Volcanic-sedlmentary series, Bureln L. Cretaeeous/M. Jurassic Between rivers Urm and Laki-Urmiysk, Burein region, Kharborov, Soviet Far East. 44z Downloaded from http://sp.lyellcollection.org/ by guest on September 29, 2021

Items

Radiometric age K-Ar (~B = 4"72 × IO-l°year-1; ;re = 0"557 × Io-t°year-1) Porphyries K (%) 4°Ar*/4°K Age (m.y.) (x) o.76 o.oo66 II 5 [IIO] (2) I'22 0"0066 115 [IIO] (3) l'o 3 0"0070 I22 [IX6] Average age: i x8 Ix x2]m.y.

(I) and (2) were from pebbles in an interformational conglomerate.

Stratigraphical age. Lower Cretaceous (Neocomian). Sedimentary intercalations in this series contain a Lower Cretaceous flora, and the series rests on sandstones, argillites, and aleurolites with Lower and Middle Jurassic ammonites.

References Bmovs~YA, E. V. & POta~vAYA, N. I. x96o (see Item 336). POT~VAYA, N. I. x96x (see Item 322). [R. Casey]

Stratigraphical comment. Geological and palaeontological evidence for a Neocomian age for this series seems slender. R. Casey

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