Carboniferous Megafaunal and Microfaunal Zonation in the Northern Cordillera of the United States
GEOLOGICAL SURVEY PROFESSIONAL PAPER 613-E
Carboniferous Megafaunal and Microfaunal Zonation in the Northern Cordillera of the United States By WILLIAM J. SANDO, BERNARD L. MAMET, and J. THOMAS DUTRO, JR.
CONTRIBUTIONS TO PALEONTOLOGY
GEOLOGICAL SURVEY PROFESSIONAL PAPER 613-E
A comparison of a %onal scheme based on corals and brachiopods with foraminiferal %onatio.n in the Mississippian rocks of Montana^ W^yoming, Idaho, and Utah
UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1969 UNITED STATES DEPARTMENT OF THE INTERIOR WALTER J. HICKEL, Secretary
GEOLOGICAL SURVEY William T. Pecora, Director
For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 75 cents (paper cover) CONTENTS
Page Page Abstract______El Comparison of zonation schemes Continued Introduction ______1 Identification in different depositional provinces.___ E19 O Purpose and scope-___--___-____-____--_-_-______- _w Correlation of zone boundaries....-.-_.__-_ 19 Coral-brachiopod zonation______5 Post-Madison hiatus.______20 Historical development.______5 Absence of other gaps in the record.______20 Distribution, composition, and criteria for recogni Intracontinental and intercontinental correlations. 20 tion. ______5 Lodgepole Limestone..______-__----_--_-- 20 Limitations.______11 Mission Canyon Limestone-______--- 22 22 Foraminiferal zonation.______12 Little Flat Formation.______Monroe Canyon Limestone. ______22 Historical development.______12 Amsden Formation ______23 Distribution, composition, and criteria for recogni Big Snowy Group______-____ 23 tion....-.-.-..------... ______13 Conclusions.______23 Limitations.______17 23 Comparison of zonation schemes.______17 References cited.______Integrity of superposition______17 Index.______27
ILLUSTRATIONS
Page PLATE 1. Stratigraphic diagram showing positions of foraminiferal samples in stratigraphic sections, northern Cordilleran region. ______In pocket FIGURE 1. Map of northern Cordilleran region, showing location of stratigraphic sections and boundaries between Mis- sissippian depositional provinces. ______E2 2-6. Charts: 2. Historical development of megaf aunal zonation in the northern Cordillera______6 3. Ranges of significant coral taxa in megafaunal zones of the Mississippian in the northern Cordillera- __ 7 4. Ranges of significant brachiopod taxa in megafaunal zones of the Mississippian in the northern Cordil lera ______8 5. Ranges of significant Cordilleran foraminiferal taxa in Mamet Carboniferous zonation scheme ______14 6. Ranges of northern Cordilleran foraminiferal samples in the Mamet zonation scheme for the Lower Carboniferous compared with megafaunal zone designations for the same samples. ______18 7. Correlation chart showing inferred relationships of faunal zones, principal European and American time- stratigraphic divisions, and Cordilleran and type Mississippian formations, ______21
TABLE
Page TABLE 1. Register of fossil localities E3
CONTRIBUTIONS TO PALEONTOLOGY
CARBONIFEROUS MEGAFAUNAL AND MICROFAUNAL ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES
By WILLIAM J. SANDO, BERNARD L. MAMET, and J. THOMAS DUTRO, JR.
ABSTRACT America is a serious deterrent to precise time-strati- > mparison of a 12-zone biostratigraphic scheme based on graphic analysis. Purely lithostratigraphic techniques, «*i and brachiopods with, a 15-zone scheme based on for- currently popular in this country, are not an adequate irifers results in consistent chronostratigraphic correlations substitute for time-tested biostratigraphic methods. Be t"ie Mississippian of the northern Cordilleran region both Mn the Cordilleran basin and with the type Mississippian se- cause of the many diverse sedimentary environments T"e. Except for the Kinderhook (early Tournaisian) interval, represented in the Mississippian of North America, it : -esolution of the foraminiferal zones is as fine or finer than seems unlikely that a single scheme of biostratigraphic t of the megaf aunal zones. A higher degree of cosmopolitanism zonation will ever prove to be satisfactory for the entire t 3 foraminiferal faunas makes them generally more useful continent. Moreover, no single group of fossils seems to r megiafaunas for correlation with the type Mississippian " standard Carboniferous sequences in western Europe. hold the key to temporal relationships in all parts of ]] o following correlations of northern Cordilleran formations North America. A series of zonation schemes, each based 'ndicated by both megafaunal and foraminiferal faunas. (1) on the distribution of many kinds of fossils in a partic ^ Lodgepole Limestone ranges in age from late Kinderhook to ular sedimentary basin or province, is a logical alternate irie Osage (pre-Burlington to earliest Keokuk). This age solution to the problem. Such an endeavor will g"i coincides approximately with the early and middle Tour- ^ : an (upper part of Tnl-Tn2) of western Europe. (2) The take many years of careful study by teams of *=:ion Canyon Limestone ranges in age from middle Osage to biostratigraphers. 1;- Meramec (early Keokuk to middle Salem). This interval Two of the authors of this report (Sando and Dutro) approximately equivalent to the late Tournaisian (Tn3) to have devoted the better part of the past 10 years of their 1;- Visean (VI) interval of western Europe. (3) A widespread research to definition and testing of a zonation scheme t is with a minimum time span represented by the upper part t 3 Salem Limestone (V2a of western Europe) separates based principally on corals and brachiopods for the t-Madison strata from the Madison Group. (4) The Little Mississippian of the northern Cordilleran region, t Formation is of middle Meramec (early St. Louis) age encompassing parts of Idaho, Montana, Wyoming, and correlates with a part of the middle Visean (V2b and lower- Utah. The results of recent work by C. A. S'andberg and "t V3a) of western Europe. (5) The Monroe Canyon Lime- Gilbert Klapper on the distribution of conodonts in the ir. ranges in age from middle Meramec (late St. Louis) r^gh most of the Chester. This interval includes the late uppermost Devonian and lowermost Mississippian strata *an and early Namurian (V3a-E2) of western Europe. (6) in the same area have been incorporated in the zonation. : Amsden Formation of Wyoming ranges in age from Late Some of the zones have also been recognized and used sfssippian to Pennsylvanian. The oldest fossils found in by Helen Duncan and Mackenzie Gordon, Jr., in the , msden are of middle Chester age; late Chester fossils are Great Basin region of Utah. x present. (7) The Big Snowy Group of southwestern Montana x contains faunas of middle and late Chester age. Although the megafaunal zonation thus devised is useful in establishing relationships within the Cordil INTRODUCTION leran basin, important provincial differences in the T^e lack of a practical comprehensive system of faunas make it difficult to correlate them precisely with ral zonation for the Mississippian 1 rocks of North standard stratigraphic units in the type area of the Mississippian. Moreover, relationships between the ""« Mississippian System of American usage includes the Lower 3rr»iferous and the lower part of the Upper Carboniferous of Euro- Mississippian-Pennsylvanlan boundary was originally placed at an * usage. It extends from the lower part of the Tournaisian to a unconformity, and Homoceras Zone cephalopoda have not been found tHn above the Eumorphoceras Zone of the Namurian. Opinion in the United States (Gordon, 1964, p. 83). However, recent unpublished rding the position of the Devonian-Mississippian boundary in studies of Mississippian Foraminifera in south-central Idaho by Mamet rica has fluctuated in a manner similar to that regarding the indicate the presence of foraminiferal faunas equivalent to the Homoceras ">rian-Carboniferous boundary in Europe (Mamet, 1968a). The Zone faunas of Europe. El E2 CONTRIBUTIONS TO PALEONTOLOGY
Cordilleraii zones and the classic marine Lower Carbon 112° 111° 110° 109° 108° 107° iferous sequences of England and western Europe can 48' .15 be established only in very broad terms. The results of studies of Carboniferous Foraminifera by Mamet offer a possible solution to the difficulties encountered in cor MONTANA DEPOSIT1ONAL relating the megaf aunal zones outside the Cordilleran 13, '14 region. After having studied the Lower Carboniferous 47= foraminiferal sequences in the classic Tournai and Vise PROVINCE areas of Belgium, Mamet extended his work during the past ten years to England, France, the U.S.S.E., and North Africa. Recently, he has been engaged in biostrat- igraphic studies in western Canada and in the area of 46' the type Mississippian in the United States. The out .11 .12 come of these studies is a scheme of 15 Lower Carbon iferous foraminif eral zones which can be recognized in appropriate carbonate f acies on a worldwide basis. .10 45' _ _ / _ _ MONTANA PURPOSE AND SCOPE WYOMING The purpose of this report is to present the results of a joint study of the zonation problem in the Missis MONTANA. sippian of the northern Cordilleran region. Approxi IDAHO mately 300 samples collected from stratigraphic sections WYOMING 44- zoned megaf aunally by Sando and Dutro were searched DEPOSITION AL for Foraminifera by Mamet by means of approximately N 500 thin sections. These samples were taken from the PROVINCE matrix of specimens used in megafaunal zone deter .9 .16 mination. One hundred and five samples from 20 strati- .17 graphic sections proved favorable for foraminif eral zone 43' \I 7 identification. LJ\I % 8 Locations of stratigraphic sections, shown in figure .18 1, are as follows: 1. Little Flat Canyon 2, NW% see. 20 and S% sec. 17, T. 7 S., R. 40 E., Bannock County, Idaho. 42° _9_ JJ 19." T] 2. Little Flat Canyon 1, SE% sec. 20, T. 7 S., R. 40 E., 4 20. Bannock County, Idaho. 50 100 MILES 3. East Canyon, NE% sec. 7, T. 9 N., R. 2 E., Cache County, Utah. 4. Old Laketown Canyon, Wi/2 sec. 32, T. 13 N., FIGURE 1. Map of northern Cordilleran region, showing loca R. 6 E., Rich County, Utah. tion of stratigraphic sections referred to ir text and 5. Sheep Creek, sec. 28 '(approx.), T. 1 N., R. 45 E., boundaries between Mississippian depositional provinces established by Sando (1967b). Bonneville County, Idaho. 6. Black Mountain, SE}4 sec. 23 and Wl/2 sec. 24, 12. Sacajawea Peak, Ni/2 sec. 27, T. 2 N., R. 6 E., T. 3 N., R. 43 E., Bonneville County, Idaho. Gallatin County, Mont. 7. Haystack Peak, sec. 19, T. 34 N., R. 117 W., Lincoln 13. Monarch-U.S. 89, sees. 22 and 27, T. 16 F., R. 7 E., County, Wyo. Cascade County, Mont. 8. Covey Cut-off, sec. 27, T. 34 N., R. 117 W., Lincoln 14. Dry Fork, sec. 36, T. 16 N., R. 7 E., Cascade County, County, Wyo. Mont. 9. Hoback Canyon, sec. 3, T. 38 N., R. 115 W., Teton 15. Little Chief Canyon, sees. 19 and 30, T. 26 N., County, Wyo. R. 25 E., Blaine County, Mont. 10. Baldy Mountain, sees. 26,27 and 35, T. 7 S., R. 3 W., 16. Dinwoody Canyon, NE% sec. 11, WWy± sec. 12, Madison County, Mont. Si/2 sec. 1, T. 4 N., R. 6 W., Fremont County, Wyo. 11. Logaii, sec. 25, T. 2 N., R. 2 E., Gallatin County, 17. Bull Lake Creek, SE% sec. 3 and Sy2 sec. 2, T 2 N., Mont. R 4 W., Fremont County, Wyo. CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E3 18. Sinks Canyon (North), Ei/2 sec. 18, T. 32 N., zonal designation, plotted to scale on a stratigrapl ic E. 100 W., Fremont County, Wyo. diagram. 19. Buck Spring, NW% sec. 33, T. 23 N., E. 88 W., The aims of this paper are (1) to summarize the Carbon County, Wyo. coral-brachiopod zonation already established in the Mississippian sequences of Montana, Wyoming, Idaho, 20. Meadow Ranch, sec. 25, T. 22 N., E. 88 W., Carbon and Utah, (2) to establish equivalent Carboniferous County, Wyo. foraminiferal zonation in the same area, (3) to compare In table 1, the samples that form the basis of this the zonation schemes in order to test the internal study are listed by locality number; location of strati- validity of both approaches, and (4) to determine mere graphic section, stratigraphic position, and zonal precisely the ages of the zones in terms of the type designations are provided for each sample. Plate 1 Mississippian and standard sequences of the Car shows the positions of samples, each identified as to boniferous in western Europe.
TABLE 1. Register of fossil localities
USGS Local upper ity in Stratigraphic section Stratigraphie position Megafaunal Foraminiferal Paleozoic fig. 1 zone zone loc. No
6965 8 Covey Cut-off_-_- _ _ _ Amsden Formation, 250-260 ft above base ______K 17-18 (?) 16209 9 Hoback Canyon Amsden Formation, 117.8-119.8 ft above base. ._ . ___ K 18 16211 9 _ _ _do_____-_-_- _ _ Amsden Formation, 197.3 ft above base__- ______-_ _ ___ Pennsyl- post-18 vaman 16942 4 Old Laketown Canyon____ Lodgepole Limestone, 400-600 ft above base_ __ _._ Ct 7 16943 4 _ _ _do______Lodgepole Limestone, upper 2ft______.___ Ci 7 16950 4 _-___do__--___----__---._ Little Flat Formation, 39 ft below top______._ E 13 16951 4 _____do__-______Little Flat Formation, 12 ft below top______E 13 16953 4 ___-_do_-_-__--_-___-__._ Monroe Canyon Limestone, 6 ft above base___--_- .___ F 14 16954 4 _____do______Monroe^Canyon Limestone, 23-30 ft above base __ F 14 17360 11 Logan. _____ Lodgepole Limestone, 256-266 ft above base.. ______. B pre-7 17365 11 _____do_-______.__ Lodgepole Limestone, 348.8 ft above base______.__ .__ Ci 7 17377 11 _____do_-_-__---_-_-_---_ Mission Canyon Limestone, 19.7 ft above base _ _ _ _ _._ C2 8 17378 11 __--_do__--______Mission Canyon Limestone, 78.4 ft above base_-__- ____ _.- C2 8 17380 11 __ _ do______Mission Canyon Limestone, 269.2 ft above base______C2 8 17381 11 _____do______Mission Canyon Limestone, 322.9 ft above base__ _ _- C2 8 17383 11 _____do ______Mission Canyon Limestone, 523.8 ft above base. _ _ __. C2 9 17494 10 Baldy Mountain. Big Snowy Group, 255-280 ft above base ______..___ K 17-18(?) 17496 10 __.__do______Big Snowy Group, 367-379 ft above base. ___ K 17-18(7) 17498 10 ___..do_ _ Big Snowy Group, 437-447 ft above base _ .___ K i7-i8(?: 17848 7 Haystack Peak Lodgepole Limestone, 6 ft above base ______A pre-7 17849 7 ..____do______Lodgepole Limestone, 18-22 ft above base. ______.__ A pre-7 17855 7 ._-_ do_____ Lodgepole Limestone, 159-163 ft above base. _ ___ .___ B pre-7 17856 7 .___-_do______Lodgepole Limestone, 166-171 ft above base _ _ .___ B pre-7 17859 7 .___._do______Lodgepole Limestone, 178-183 ft above base. _ ___ .___ C_ 7 17860 7 __.__do. ______Lodgepole Limestone, 183-188 ft above base ______C_ 7 17879 7 ..____do______Mission Canyon Limestone, 0-30 ft above base... _ .___ C2 8 17882 7 ..._._do______.______Mission Canyon Limestone, 96-100 ft above base___ .___ C2 8 17902 7 ..____do______Mission Canyon Limestone, 544-568 ft above base __ _ D 10-11 17905 7 . ..do______._. ______Amsden Formation, 177-178 ft above base.-___- __. K 17 17906 7 .._..do______. ______Amsden Formation, 184-187 ft above base ______K 17 17907 7 ._-___do____.______Amsden Formation, 199-209 ft above base ______. K 18 17929 10 Baldy Mountain _ _ _ Lodgepole Limestone, 278.3 ft above base ______.___ Ci 7 17950 10 .___ _do__ _ Lodgepole Limestone, 575.3-578.3 ft above base_. ___ c, 7 17954 10 -__._do______Lodgepole Limestone, 699.3 ft above base______c, 7 17960 10 _____do______Mission Canyon Limestone, 348-368 ft above base_ ___ .__ C2 9 17964 . ___._do______Mission Canyon Limestone, 620.5-640.5 ft above base. _ _ . D 11 18634 2 Little Flat Canyon 1_ _ _ Lodgepole Limestone, lower 15 ft______._ A pre-7 18637 2 _ _ do______Lodgepole Limestone, 13-23 ft above base______.__ B pre-7 18645 2 .-____do______Lodgepole Limestone, 186-198 ft above base_ _ _ _ _._ C_ 7 18651 2 _____do__.______Little Flat Formation/28-32 ft above base _ pre-E 13-14 18655 2 -_--_do_____-______Little Flat Formation, 488 ft above base. __ _-___-----_ pre-E 13-14 18667 1 Little Flat Canyon 2. _ _ Little Flat Formation, 584 ft above base- ______E 13-14 18669 1 _--__do__- _ Little Flat Formation,|f597 ft above base. ___ E 13-14 18677 1 _____do ______Little Flat Formation, 761.5 ft above base _ __. E 13-14 18680 1 _____do______Little Flat Formation, 815 ft above base______._ _ _ E 13-14 E4 CONTRIBUTIONS TO PALEONTOLOGY
TABLE 1. Register of fossil localities Continued
USGS Local upper ity In Stratlgraphic section Stratigraphic position Megafaunal Foramlniferal Paleozoic fig. 1 zone zone loc. No.
18689 1 Little Flat Canyon 2______Monroe Canyon Limestone, 225.5-245.5 ft above base _ __ _ F 14 18699 1 __.__do______- Monroe Canyon Limestone, 407.5-412.5 ft above base. _ _ _ _ _ F 14-15 18700 1 _____do . . ______Monroe Canyon Limestone, 418.5-422.5 ft above base______F 14-15 18702 1 _-__.do_. ______Monroe Canyon Limestone, 460 ft above base______F 15 18703 1 --___do____--_----_-___ Monroe Canyon Limestone, 468 ft above base ______F 15
18704 1 _____do ______Monroe Canyon Limestone, 488-508 ft above base ______F 15 18705 1 do ______Monroe Canyon Limestone, 588-600 ft above base______pre-K 16i 18706 1 do __ Monroe Canyon Limestone, 613 ft above base ______pre-K 16i 18707 1 _____do-_____--_.______Monroe Canyon Limestone, 628 ft above base.. ______pre-K 16i 18708 1 _____do__--______Monroe Canyon Limestone, 63 8 ft above base ______K 16i(?)- 16s
18709 1 ___-_do______Monroe Canyon Limestone, 645-647 ft above base.______K 16s 18710 1 _____do______--_- Monroe Canyon Limestone, 661 ft above base. ______K 16s 18711 1 _____do__-______-_-_-__ _ Monroe Canyon Limestone, 688 ft above base ______K 16s-17 18715 1 _____do-_-____-____--__ . Monroe Canyon Limestone, 805-825 ft above base.. ______K 17-18 18720 1 ____.do______Monroe Canyon Limestone, 905 ft above base.. ______K 18
18721 1 _____do______- Monroe Canyon Limestone, 919-923 ft above base______K 18 20047 3 East Canyon______-. Brazer Limestone (as used by Mullens and Izett, 1964), 50 ft K 17 below top. 20059 6 Black Mountain. _.. __ _ Lodgepole Limestone, 227.5 ft above base. ______Ci 7 20064 6 _____do______.______Lodgepole Limestone, 340.5 ft above base _ ...... _ ... Ci 7 20065 6 do . Lodgepole Limestone, 355.5 ft above base______Ci 7 20067 6 _____do______.______Lodgepole Limestone, 402.5 ft above base ______Ci 7 2006S 6 _-___do_-______-___.___ _ Lodgepole Limestone, 404.5 ft above base. ______Ci 7 20070 6 _____do_____-______._ Lodgepole Limestone, 415.5 ft above base ___ __ .______Ci 7 20079 6 _____do----____-______. Lodgepole Limestone, 612.5-617.5 ft above base______Ci 8 20085 6 _____do_-_.______Lodgepole Limestone, 668.5-673.5 ft above base______Ci 8 20088 6 _____do______.______Mission Canyon Limestone, 35-38 ft above base______.___. C2 8 20089 6 _____do-______-____.__ _ _ Mission Canyon Limestone, 44-47 ft above base ______. C, 8 20100 6 _____dO___-_--____.____ _ Mission Canyon Limestone, 630-634 ft above base ______C2 9 20104 6 __.__do-_. ______Mission Canyon Limestone, 825.5-845.5 ft above base- _ _ _ D 10-11 20107 5 Sheep Creek ______Lodgepole Limestone, 196.5-200.5 ft below top______Ci 7
20106 5 ____-dO__-______--____ _ Mission Canyon Limestone, 101-118 ft above base ____ _ C2 8 20108 5 ____.do_____. ______Mission Canyon Limestone, 38-48 ft above base ______C2 8 20647 12 Saeajawea Peak ______Lodgepole Limestone, 251.5 ft above base______B pre-7 20652 12 do --. . . _ Lodgepole Limestone, 295.8-308.8 ft above base ______Ci 7 20653 12 _____do______-_-.______Lodgepole Limestone, 322.8-334.3 ft above base___------___ Ci 7 20666 12 do _ _ Lodgepole Limestone, 567.3 ft above base. ______. Ci 7-8 20673 12 _____do______--_-__. __ Mission Canyon Limestone, 51-52 ft above base ______C2 8 20675 12 _____do___._. ---__.____ Mission Canyon Limestone, 78-93 ft above base______C2 8 20678 12 _____do__---_----______Mission Canyon Limestone, 240-242 ft above base ______C2 9 20701 15 Little Chief Canyon. ______Lodgepole Limestone, 5 ft above base____--______---_--_. A pre-7 20708 15 _____do_-----_-_--_--__ _ _ Lodgepole Limestone, 182- 187 ft above base. ______c, 7 20710 15 _____dO-_-__--_-.______Lodgepole Limestone, 204-205 ft above base__-______Ci 7 20716 15 ____-do__-______.___ _ Lodgepole Limestone, 189-205 ft above base______c, 7 20730 15 _____do___--______- Lodgepole Limestone, 439.7-442.7 ft above base______c, 7 20740 15 do _ Mission Canyon Limestone, 30-35 ft above base______C2 8 20743 15 do Mission Canyon Limestone, 280 ft above base ______C2 8 20751 14 Dry Fork______Lodgepole Limestone, 1.5 ft above base ___--___-____-- _ _ A pre-7 20771 14 _do______Lodgepole Limestone, 290.5-293.5 ft above base ______Ci 7 20787 14 _____do___.______Lodgepole Limestone, 66 1-669.5 ft above base- ______G! 7 20795 14 do __ Mission Canyon Limestone, 70-75 ft above base- ______C2 8 20798 13 Monarch-U.S. 89______Mission Canyon Limestone, 281.2-286.2 ft above base____ C2 9 20799 13 _____do-_------_--_ __ Mission Canyon Limestone, 309.2 ft above base__-___- _____ C2 9 20804 13 ___ do_-_-__-_ ____ . _ Mission Canyon Limestone, 617.2 ft above base______D 10 20805 13 _____do______Mission Canyon Limestone, 695.2-696.2 ft above base. _ _ __ D 10 21647 18 Sinks Canyon (North) __ Madison Limestone, 197-200 ft above base ______C2 9 21648 18 _-__-do_-______.______Madison Limestone, 242.5-250.5 ft above base______C* 9 21677 17 Bull Lake Creek___ _ _ Madison Limestone, 656.5-659.5 ft above base______D 10-11 21692 16 Dinwoody Canyon______Madison Limestone, 792.5-807.5 ft above base. ______D 10-11 21725 19 Buck Spring _ Amsden Formation, 140.5-142.5 ft above base_ _ _ __ Penn.? post- 18 21729 20 Meadow Ranch. _ _ _ Amsden Formation, 92.5-95.5 ft above base. ______Penn. post- 18 CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E5 CORAL-BRACHIOPOD ZONATION recognition of a conodont zonation (Klapper, HISTORICAL DEVELOPMENT Sandberg and Klapper, 1967) and inclusion of th. ,se beds in the Madison. It became apparent that the Lower The present scheme of megafaunal zonation had its /Siphonodella wenulata Zone of Klapper (1966) and origin in biostratigraphic studies of the Madison Group Sandberg and Klapper (1967) coincided with Zone A begun in 1954 by Sando and Dutro, who were assigned of Sando and Dutro (1960). The conodont work aho this research project in support of general geologic in resulted in definition of two zones, Siphonodella sand- vestigations by the U.S. Geological Survey in the north bergi-S. duplicata Zone and 8. sulcata Zone, for the ern Rocky Mountain region. Studies of nine strati- earliest Mississippian beds beneath Zone A. graphic sections in northeastern Utah, western Wyo ming, and Montana led to the recognition of five coral In a synthesis of Mississippian stratigraphy in the zones (A, B, Ci, C2, and D) for the Madison Group and northern Cordilleran region, Sando (1967b) presented Brazer Dolomite (Sando and Dutro, 1960; Sando, 1960) a composite zonation of the entire Mississippian inter (fig. 2). The Madison coral zonation was subsequently val. A sequence of 12 megafaunal zones incorporated all applied to stratigraphic problems in northwestern Mon the previous work discussed above. Two major cycles of tana (Mudge and others, 1962) and central Wyoming sedimentation were recognized, Madison cycle and a (Sando, 1967a). This zonation concept has also been later, post-Madison cycle, separated by a widespread used extensively since 1960 in unpublished reports to episode of epeirogenic uplift. The Madison interval was Geological Survey field geologists on numerous collec divided into the five zones of Sando and Dutro (1960) tions from many localities in the northern Cordilleran plus a newly-recognized pre-A Zone at the base, pro region. posed to include the cul conodont fauna of Klapper Study of the Mississippian sequence in the Chester- (1966). The post-Madison interval included six zores fied Range, southeastern Idaho, led to the recognition of that began with a newly recognized pre-E Zone fol three coral zones (E, F, and K) and four braehiopod lowed by coral zones E and F of Dutro and Sando zones in post-Madison Upper Mississippian strata (1963a). A newly recognized pre-K Zone based on (Dutro and Sando, 1963a). One of these coral zones and brachiopods was delineated above Zone F. Thence fol two of the brachiopod zones were also identified in beds lowed Zone K of Dutro and Sando (1963a), which was of Late Mississippian age in western Wyoming and in turn overlain by a newly recognized post-K Zone southwestern Montana (Dutro and Sando, 1963b). The based on brachiopods. This 12-zone megafaunal system coral zonation recognized in these areas is very similar is the one used in the present report. to the scheme developed earlier by Parks (1951) for DISTRIBUTION, COMPOSITION, AND CRITERIA FOR the Upper Mississippian sequence in northern Utah. RECOGNITION The three coral zones have been tested subsequently in unpublished reports to Geological Survey geologists The zonation scheme embodies both assemblage zone working in southeastern and south-central Idaho. and range zone concepts. With the exception of the Studies by Mackenzie Gordon, Jr., and Helen Duncan pre-A Zone, which is based 011 conodonts, the zoral (written comnmn., 1964) resulted in a zonation scheme, indices are genera and species of corals and brachio based on corals and brachiopods, for the Osage-Chester pods. The ranges of significant zonal fossils are shown interval of the Great Basin area of Utah. In addition to in figures 3 and 4. The zones are identified by means of the E (Ekvasophyllum,) F (Faberophyllum), and K assemblages of these fossils in some occurrences and ( Oaninia) Zones of the Chesterfield Range, this scheme by means of individual taxa of restricted range in included three zones in the Upper Mississippian interval others. beneath Zone E, a pTs-Oaninia Zone between Zones F The oldest unit recognized in the zonation scheme is and K, and a post-Oaninia Zone of Chester age above the pre-A Zone, which includes the two cul conodcnt Zone K. Subsequent unpublished studies by Gordon zones (/Siphonodella sandbergi-S. duplicata Zone and established the presence of the post-Oaninia Zone in the S. sulcata Zone) of Sandberg and Klapper (1967). lower part of the Amsden Formation of central The conodonts occur in the upper tongue of the Cottcn- Wyoming. wood Canyon Member of the Madison Limestone in When the original Madison coral zonation was pro central Wyoming and of the Lodgepole Limestone in posed (Sando and Dutro, 1960), noncoralliferous beds southern Montana. (See Klapper, 1966, and Sandberg of earliest Mississippian age were included in the sub and Klapper, 1967, for detailed discussions of the cono jacent, predominantly Devonian formations. Subse donts and distribution of these beds.) The upper part of quent detailed studies of these strata and their conodont the pre-A Zone is characterized by the assemblage of faunas by C. A. Sandberg and Gilbert Klapper led to Siphonodella sandbergi, S. duplicata, and Pseudopoly- 330-481 69 2 E6 CONTRIBUTIONS TO PALEONTOLOGY
Gordon and Sando and Dutro and Sandberg Parks Mudge, Sando Dutro and Duncan Klapper Sando and Sando (1951) Dutro (1960); and Dutro Sando Sando Sando (1960) (1962) (written (1966) (1967a) Klapper (1967b) (1963a) (1963b) commun., (1967) 1964)
Montana, SW. Montana, SE. Idaho western SW. Montana Great northern Montana western and Northern NW. SE. and Central Utah Wyoming, Basin, Wyoming, and Wyoming and central and northern Montana Idaho western Utah western Wyoming Wyoming, and Utah Wyoming South Dakota northern Utah
Not Not Post- Post-K discussed discussed Cam ?a'a
Spirifer Caninia K K brazer- Caninia K
Sp infer bruzer- ianus
Pre- Pre-K Caninia Triplophyllites Not Not Not discussed discussed Lithostrotion discussed Striatifera u-kitneyi- brazeriana F. leathuniense Fabero- F F FabcrophyUum Striatifera phyllum occult um-
Ekvasophyllum Ekvaso- E E inclinatum Erhino- phylhim confhtis cf.E. Not Not altfrnatus discussed discussed A mania? Quadra- Rhnpalolasma Pre-E hirsuti- formis hirsutifornns
D D D D
Hiatus
Cz C 2 Not discussed Homalo- C phyllites C Vesiculo- phyllum c, Ci Ci
Not 7 discussed
B B B B
A-B?
Lower Lower A A A Siphonodella Siphonodella A crenitlata. crenulata
Siphonodella, sandbergi- Not Not Not cu\ Not - S. duplicata Pre-A discussed discussed discussed fauna discussed Siphonodella swicata
FIGURE 2. Historical development of megafaunal zonation in the northern Cordillera. CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E7
INTERVAL ZONE CORAL RANGES
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A
Pre- A
FIGURE 3. Ranges of significant coral taxa in megafaunal zones of the Mississippian in the northern Cordillera. Solid range lines indicate common to abundant occurrences; dashed lines denote rare occurrences. oo
FIQUEE 4. Ranges of significant braehiopod taxa in megafaunal zones of the Mississippian in the northern Cordillera. Solid range lines indicate common to abundant occurrences; dashed lines denote rare occurrences. CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E9 gnathus dentUineata. The lower part, known only from yon section in Montana (Mackenzie Gordon, Jr., Windy Gap in west-central Wyoming, is characterized commun., 1967). Zone A characterizes the lower 10-50 by Siphonodella sulcata. No brachiopods have been feet of the Paine Shale Member of the Lodgepole found in the Cottonwood Canyon Member, but Syring- Limestone over a broad area in Montana, western Wyo pora occurs in the upper part at a few localities in ming, southeastern Idaho, and northeastern Utah. At central Wyoming. most localities, this interval is characterized by glau- Brachiopods from the upper part of the Sappington conitic crinoidal limestone. The zone has also been Member of the Three Forks Formation of southwestern provisionally identified in dolomitic beds above the Montana also are included in the pre-A Zone. Despite Cottonwood Canyon Member of the Madison Limestone recent detailed work on the biostratigraphy of the in central Wyoming. Sappington (Rodriquez and Gutschick, 1967; Gut- In Zone B Amplexus is the most common coral, and schick and Rodriquez, 1967), the age and correlation Gyathaxonia^ Zaphrentites, and Palaeacis are rare, of parts of this unit remain controversial. Evaluation Among the brachiopods are RMpidomella aff. R. dimi of the Sappington fauna involves not only comparison nutiva Rowley, "Spirifer" aff. "$." fiiplicoides Weller, of this fauna to Mississippi Valley faunas but also the Oleiothyridina cf. G. tenuilineata (Rowley), and question of whether the Louisiana Limestone is of "Spirifer" aff. "$." centronatus Winchell, which con Carboniferous or Devonian age, a problem that has not tinue into Zone B from subjacent strata. New elements been resolved to the satisfaction of all paleontologists in the brachiopod fauna include Gyrtina cf. "burlw.g- who have worked on the Louisiana Limestone faunas. tonensis Rowley, which is seemingly restricted to the Although a detailed discussion of the age and correla zone, and "Torynifer" cf. "TV' cooperensis (SwaHoy), tion of the Sappington is beyond the scope of this Orbinaria aff. 0. pyxidata (Hall), Retichonetes cf. paper, we provisionally believe that the Louisiana Lime R. logani (Norwood and Praten), Leptagonia cf. L. stone is of Devonian age and that the Carboniferous analoga (Phillips), land Brachythyris aff. B. suborbi- part of the Sappington includes units F, G, and H of cularis (Hall), which continue into superjacent beds. Gutschick and Rodriquez (1967, p. 601, fig. 1). Unit I Zone B corresponds approximately to the upper part of of Gutschick and Rodriguez is regarded as an extension the Paine Shale Member of the Lodgepole Limestone, of the upper tongue of the Cottonwood Canyon Mem which consists of poorly fossiliferous thin-bedded sT^y ber of the Lodgepole Limestone. Consequently, the prin and argillaceous limestone. The zone has been recog cipal elements of the brachiopod fauna that we include nized throughout the outcrop area of the Lodgepole in the pre-A Zone largely consist of undescribed species Limestone and is also present in the Allan Mountrin of Schuchertetta, "Oamarotoechia" "Ohonetes" "Rhy- Limestone of northwestern Montana. tiophora" "Unispirifer" "iSpirifer" Gomposita, and In Zone Ci, the principal coral indices are Cleisto- Syr ing o thyris. pora placenta (White), Michelinia expansa White, Zone A includes an assemblage of diminutive corals Lithostrotionella microstykim (White), and Rylstonia and brachiopods together with conodonts of the Lower cf. R. teres (Girty). Gleistopora appears to be restricted Siphonodella crenulata assemblage of Klapper (1966) to the zone, and the other elements occur only raroly and Sandberg and Klapper (1967). Among the corals, above it. Homalophyllites and Zaphrentites excavatus Metriophyllum cf. M. deminutivitm Easton and an un (Girty) begin their ranges at the base of the zone, and described species provisionally referred to Permia are Vesiculophyllum becomes abundant for the first time. restricted to this zone, and Gyathaxonia cf. O. tantUla Brachiopods that range into the zone from below Hit (Miller) and undescribed species of Palaeacis, Am- do not occur above it are "Spirifer" aff. "$." "biplicoides plexus, and Zaphrentites range into overlying beds. Weller, Oleiothyridina cf. O. tenuilineata (Rowle7), Vesiculophyllum occurs rarely in the zone in central "Torynifer" cf. "TV5 cooperensis (Swallow), Orbinana Wyoming. Brachiopods restricted to the zone include aff. 0. pyxidata (Hall), Retichonetes cf. R. logani (Nor "Spirifer" aff. "$." osagensis Swallow and a small wood and Pratten), and Leptagonia cf. L. analoga species of Orurithyris. Other common Zone A brachio (Phillips). Brachythyris aff. B. suborbicularis (Hall) pods are Rhipidomella aff. R. diminutiva Rowley, is known in subjacent and superjacent beds but is most "Spirifer" aff. "$." Mplwoides Weller, Gleiothyridina common in Zone Ci. The ubiquitous and long-ranging cf. G. tenuilineata (Rowley), and "Spirifer" aff. "$." "Spirifer" aff. "8." centronatus Winchell is also present. centronatus Winchell. Cephalopods are extremely rare A species of Nucleospira seems to be restricted to the in this assemblage; Pericyclus (Oaenocyclus) sp., zone. The zone is also characterized by a large assem Pericyclus (Rotopericyclus} sp., and Gattendorfia sp. blage of brachiopod species that appear for the first have been found at one locality, the Little Chief Can time and continue to the top of Zone C2. Among these E10 CONTRIBUTIONS TO PALEONTOLOGY are Imbreoda cf. /. forbesi (Norwood and Pratten), rence of the brachiopods Quadratia hirsutiformis (Wal- Ovatia cf. O. laev-icosta (White), "Dictyoclostus" cf. cott) and "Leiorhynchus" carboniferwni Girty. "Z>." viminalis (White), "Z>." cf. "Z>." ~burlingtonensis Auloprotonia, Rhipidomella arkansana Girty, and (Hall), "Spirifer" aff. "#." fooMj Hall, Spirifer cf. & Echinoconchus cf. E. alternatus (Norwood and Prat- logani Hall, the Spirifer aff. $. roioleyi-S. grimesi com ten) also occur in the upper half of the zone. Although plex, Punctospirlfer cf. P. solidirostris (White), "Pro- corals are generally very rare in this zone, a species of ductus" cf. "P." gallatinensis Girty, and Rugosochonetes Rhopalolasm-a has been found at several localities. Zone cf. ./?. loganensis (Hall and Whitfield). Other longer pre-E has been identified at several localities in south ranging elements are Diinegelasma sp. and Cleiothy- eastern Idaho and northeastern Utah in the lower part ridina cf. (7. obmaseima (McChesney). Zone Ci corre of the Deep Creek and Little Flat Formations, sponds approximately to the Woodhurst Limestone In Zone E the principal index fossil is the corrl genus Member of the Lodgepole Limestone. This zone has been Ekvasophyltum, which appears to be restricted to this identified in the upper part of the Lodgepole wherever zone at some localities but may range into the lov^er part the Lodgepole has been studied. Elements of the zone of the overlying Zone F. Other common corals in Zone are also present in the Allan Mountain Limestone of E are the species of LitJiostrotion (Siphonodendron) northwestern Montana and in the lower part of the called LitJiostrotion whitneyi by Meek, species of the Madison Limestone of central Wyoming. Dorlodotia-Pseudodorlodotia complex, Zaphrentites cf. The principal corals of Zone C2 are Zaplirentites ex- Z. spimdosus (Milne-Edwards and Haime), a snail un- cavatus (Girty), Homalophyllites, Vesiculophyllwin, described solitary coral provisionally referred to Zaph- and several species of Syringopora. The brachiopod as rentites, and the tabulate coral Syringopora virginica semblage of this zone is dominated by the Zone Ci Butts, which may actually belong in the genus Ki'-echow- species of spiriferids and productids previously men pora. Palaeacis cuneiformis Haime occurs rarefr in the tioned. "Spirifer" cf. "$." madisonensis Girty seems to upper half of the zone. The principal brachiopods in be the only brachiopod species restricted to the zone. Zone E are Echinoconchus cf. E. alternatus (Norwood Zone C2 includes approximately the lower half of the and Pratten) and Orthotetes cf. O. Tcaskaskiensis Mission Canyon Limestone at all localities where the (McChesney), which range into the lower half of the Mission Canyon faunas have been studied. Elements of zone from below, and Anthracospirifer bifurcatus this zone also have been identified in the lower part of (Hall), which appears to be restricted to the lowa-r half. the Castle Keef Dolomite of northwestern Montana, in Other common brachiopods in the lower half are the lower half of the Brazer Dolomite of northeastern Brachythyris cf. B. subcardiiformis (Hall) and Oleio- Utah, and in the upper half of the Madison Limestone thyridina cf. O. obmajxima (McChesney), which are the of central Wyoming. only Madison fossils known to occur in the post-ftradison Zone D is characterized by the lowest occurrence of interval. Striatifera aff. S. brazeriana (Girty), a char fasciculate lithostrotionid corals, including Lithostro- acteristic Zone F brachiopod, occurs in the uppermost tion (Siphonodendron) oculinwn Sando and Diphy- part of Zone E in northeastern Utah. Zone E i? estab pfiyUutn sp. Other characteristic coral elements are lished on fossils that occur in the upper part of the CanadiphyUuml, Ankhelasma, Zaphrentites, Vesiculo- Little Flat Formation and the lowermost part of the phyllum, and Syringopora. Homalophyllites has been Monroe Canyon Limestone of southeastern Idsho and found in basal beds of Zone D at a few localities but is northeastern Utah and has also been identified in the characteristically a pre-Zone D index. Brachiopods are White Knob Limestone in south-central Idaho. generally rare, but Perditocardinia cf. P. dubia (Hall), Zone F is named from the coral genus Fdberophyllum, "/Spirifer" shoshonemis Branson and Greger, and whose range defines the limits of the zone. Oth?-r com Brachythyrisci.B.siibcardiiformis (Hall) are found at mon coral elements are species of the Dorlodotia- some localities. Zone D is the highest biostratigraphic Pseiidodorladotia complex, Zaphrentites? n. sp., and unit recognized in the Madison Group and equivalent Syringopora virginica Butts, which range into the strata. It is present in the upper half of the Mission zone from below. Species of DibunopJiyllmn and odd Canyon Limestone of Montana and western Wyoming, syringoporoids questionably referred to Syringopor- the Charles Formation of northeastern Montana, the ella are also common. Ekvasophyllum cf. E. inclinatwn uppermost part of the Sun River Member of the Castle Parks and LitJiostrotion (Siphonodendron) whitneyi Reef Dolomite of northwestern Montana, the upper part of Meek may occur rarely in the lower part. Striatifera of the Madison Limestone of central Wyoming, and the aff. S. brazeriana (Girty), which ranges into Zone F upper half of the Brazer Dolomite of northeastern Utah. from below, is the principal brachiopod index. Anthra- Zone pre-E is characterized by the restricted occur cospirifer leidyi (Norwood and Pratten) is common in CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES Ell
the upper half, whereas Spirifer brazeriamis Girty is lems in the Mississippian of the Cordilleran region. rare. Zone F is known principally from the lower part There are many limitations to the usefulness of the of the Great Blue Limestone and Monroe Canyon Lime zonation as it is presently understood, and much work stone of southeastern Idaho and northeastern Utah and remains to be done to perfect the system. Some of the the White Knob Limestone of south-central Idaho. It problems are summarized below. has also been identified in beds referred to the Amsden Incomplete taxonomy. Most of the faunas upon Formation by Klepper (Klepper and others, 1957) in which the zonation is based have been treated only super southwestern Montana. ficially from a taxonomic standpoint. Many decisions re Zone pre-K is a poorly f ossilif erous interval that has main to be made concerning the limits of species and been identified near the middle of the Great Blue Lime genera. The zones can be no more precise than the dis stone and Monroe Canyon Limestone of southeastern crimination of zonal indices. More detailed systematic Idaho. The limits of this zone are defined on criteria studies are necessary to sharpen the tools of biostrati that determine the top of the underlying F Zone and graphic discrimination. the bottom of the overlying K Zone. A few solitary Composite superposition. There is no single locality corals, possibly belonging to Zaphrentites, and the where 'all the megafaunal zones can be seen in super brachiopods AntJvracospirifer leidyi (Norwood and position. This circumstance has arisen because of a com Pratten), Spirifer brazerianus Girty, and Striatifera plicated history of sedimentation and epeirogenepis aff. 8. brazeriana (Girty) are the only fossils now during Mississippian time in the northern Rocky Moun known from this zone. tain region (Sando, 1967b). The complete zonal src- In Zone K, the principal index fossil is the coral cession, though necessarily composite, was established species Caninm ewcentrica (Meek). Other common coral after examination of many sequences of Mississipian taxa are Zaptirentites cf. Z. spinulosus (Milne-Edwards rocks, some of which provided key overlaps in various and Haime), Lithostrotionella cf. L. stelcJci Nelson, and parts of the Mississippian time interval. Nevertheless, the syringoporoids Syringoporellal and HayasaT&mai. the ultimate test of this zonation requires that it be com Caninm nevadensis (Meek) is also found in this zone pared with a suitable independent biostratigrapt ic at some localities. Zone K is also characterized by a standard. large assemblage of brachiopods. The principal brachio- Difficulties in identifying zone boundaries. Because pod elements are Spirifer brazeria/nus Girty, Antfira- the horizontal distribution of zonal indices is not uri- cospirifer leidyi (Norwood and Pratten), certain species form, the precise positions of zone boundaries are com of Diaphragm/us, and Anthracospirifer curvilateralis monly difficult to determine in any given stratigraphic (Easton). Other brachiopod species found in the Zone section. The lack of a continuous sequence of significant K assemblage will probably prove useful when more fossils at some localities may result in local uncertainties is known about their precise distribution. Zone K is a involving tens or hundreds of feet of section. At the?e widely distributed biostratigraphic unit that has been localities, arbitrary boundaries are recognized. A com identified at the top of the Great Blue Limestone and mon example is the boundary between Zones d andC2, Monroe Canyon Limestone of southeastern Idaho, in the which is difficult to place precisely at many localities but White Knob Limestone of south-central Idaho, in the which can be conveniently approximated by the con Amsden Formation of western Wyoming, and in the tact between the Lodgepole and Mission Canyon Lime Big Snowy Group of southwestern Montana. stones. Boundary indemnification can be improved only The highest Mississippian zone recognized in this by additional collecting in the poorly f ossiliferous inter paper is the post-K Zone based on unpublished brachio vals and by discovery of new fossils useful for identi pod studies by Mackenzie Gordon, Jr. The zone is pres fying the zones. ently recognized on the occurrence of Anthracospirifer Fades influences. Although environmental sensi weUeri (Branson and Greger) and an undescribed tivity of the organisms used in zonation has not proved species of Diaphragmus. Other potentially useful ele to be as important a factor as originally anticipated, ments of the brachiopod assemblage remain to be recognition of some of the zones in certain parts of the described. This zone has been identified in the Manning area studied has been made difficult because of facies Canyon Shale of southeastern Idaho and the Amsden changes. A good example is the lower part of the Madi- Formation of central Wyoming. ion Limestone of central Wyoming (Wyoming province of Sando, 1967b), where corals and brachiopods charac LIMITATIONS teristic of Zones A, B, and Ci of the Lodgepole Lime- The zonation scheme outlined above is by no means itone are greatly reduced in variety and numbers so ths.t intended as the final solution to biostratigraphic prob precise determination of zone boundaries has not been E12 CONTRIBUTIONS TO PALEONTOLOGY possible on the basis of available evidence. Similar diffi in the U.S.S.E. and western Europe since publication culties have been experienced in attempting to analyze of an important symposium by Kauzer-Chernoussova the Madison Group in subsurface sections in and near and others 1948, considerably less interest in this field the depositional center of the Williston basin of Mon has been shown by North American paleontologists. tana and North Dakota. Although some of the problems American attempts at zonation began with the pioneer may prove to be insurmountable, additional collecting study of Zeller (1950), who demonstrated that various in these poorly fossiliferous areas should resolve many parts of the Mississippian sequence in its type area could of the questions. be identified by means of evolutionary changes in the Difficulties in correlation with the type Mississip endothyroid faunas. Subsequently, Zeller (1957) pian. It became apparent early in the work on zonation published a study of 12 endothyroid sequences of Mis that many of the key fossils in the Cordilleran region sissippian age in the Cordilleran region in which he either were absent or had different vertical ranges in the recognized four widespread zones. Zeller found a close Mississippi Valley area. This is particularly striking in similarity between Cordilleran faunas and Mississippi the coral faunas but is less apparent among the brachi- Valley faunas in the Upper Mississippian, but experi opods. This provincialism has evoked a relunctance on enced difficulty in correlating the lower Missi?sippian our part to apply standard Mississippian time-strati- rocks of the two areas. graphic designations to the Cordilleran sections. Broad Woodland (1958) recognized three zones and one faunal similarities, particularly in the brachiopod subzone in the Mississippian of central Utah. Wood faunas, led to the following tentative correlations: Zones land's zonation scheme was similar to Zeller's in the pre-A, A, and B are approximately equivalent to the Osage-Meramec interval, but he also recognized a zone Mississippioii part of the Kinderhook Series; Zones Ci of Chester age not found by Zeller. Like Zeller, and C2 equate approximately with the Osage Series; Woodland was able to correlate readily the late Zones D, pre-E, E, and F represent approximately the Mississippian faunas with the Mississippi Valley area Meramec Series; and Zones pre-K, K, and post-K are but was uncertain about correlations in the Lower approximately equivalent to the Chester Series. Identifi Mississippian. Armstrong (1958, 1967) found that en cation of parts of the standard series in the Cordilleran dothyroid faunas are useful in differentiating rocks of region was based largely on arbitrary division of the Early Mississippian age from rocks of Late Mississip Cordilleran equivalents rather than on precise compari pian age in northern and central New Mexico. sons of parts of the faunal successions. For example, be Mamet (1962), having studied the Carboniferous cause the Zone D-Zone F interval equals the Mera Foraminifera of western Europe (Tournaisian, Visean, mec, Zone D is called early Meramec, Zone pre-E and E and Namurian type sections), was struck by the great are middle Meramec, and Zone F is late Meramec. More similarities1 among formaminiferal families observed in precise calibration of the megafaunal zones in terms of Europe and North America. He suggested that (1) the type Mississippian sequence requires checking these phylogenetic development of all the families i? identi conclusions against a system based on less provincial cal in Eurasia and North America, (2) there is no organisms than the ones used thus far. true provincialism in the northern hemisphere, and free Difficulties in congelation with Carboniferous stand communication persisted during most of the Lower ards. Although Hill (1948, 1957) and Moore (1948) Carboniferous, (3) a number of widespread taxa can recognized European stages (Tournaisian, Visean, and be traced all around the northern hemisphere, (4) pre Namurian) in the North American faunal succession cise correlation can be made between Eurasia ard North largely on the basis of corals, subsequent work in Europe America, (5) the Kinderhook is approximately of early and America has not produced a sharpening of the Tournaisian age, the Osage is middle to late Tournai resolution of these biostratigraphic tools. It is too soon sian, the Meramec is early to middle Visean, and the to pass judgment on the ultimate utility of corals and Chester is late Visean to early Namurian. brachiopods for intercontinental correlation because McKay and Green (1963) recognized four main much work remains to be done on these groups of fossils. successive range zones, two concurrent range zones, and However, available information does not permit the one assemblage zone in the Mississippian rocks of Al same level of biostratigraphic discrimination attained berta and attempted to correlate these rocks with the by means of cephalopods, conodonts, and foraminifers. type Mississippian and sections in the Western United FORAMINIFERAL ZONATION States by means of endothyroid faunas. Th<\y also HISTORICAL DEVELOPMENT pointed out that non-endothyroid genera were present Although Lower Carboniferous foraminiferal zona and might be useful as zone fossils. Studies of the dis tion has been the subject of much study and discussion tribution of foramanifers in the Eedwall Limestone of CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES F13 Arizona by Skipp (1963, 1964, 1969) led to the recog permit reliable identification of Zone 6 of Mamet a nd nition of six zones based on endothyroids and tournayel- Skipp (1969). This assemblage is found in the Paine lids and ranging in age from Kinderhook to late Shale Member of the Lodgepole Limestone in south Meramec. Skipp, Holcomb, and Gutschick (1966) eastern Idaho, western Wyoming, and Montana. summarized the known distribution of tournayellids in Zone 7 is characterized by the acme of Septaglovw- the Mississippian of North America. spiranella primaeva (Eauzer-Chernoussova, in Cherny- Mamet and Skipp (1969) presented a comprehen sheva), S. damae Lipina, and Rectoseptaglomospira- sive outline of foraminiferal zonation of the Mississip nella. Ohernyshinella (O. tumulosa Lipina), Septa- pian of North America. The distribution of all Early brunsiina, Palaeospiropleotarnmina, and Latiendothyra Carboniferous genera known in North America was are other, less abundant, elements. This assemblage is recorded, 14 assemblage zones were established, and the found in the Woodhurst Limestone Member of the standard units of the type Mississippian were corre Lodgepole Limestone in southeastern Idaho, northes st lated with their counterparts in the standard western ern Utah, western Wyoming, and Montana. European sections of the Lower Carboniferous. Mamet Zone 8 is recognized by the outburst of Tuberin- and Skipp's paper formed the foundation for the dothyra tuberculata (Lipina) and by abundant Septa- present work, which treats the occurrence of the foram glomospiranella primaeva (Eauzer-Chernoussova, in iniferal zones in the northern Cordilleran region in Chernysheva), Septabrunsiina parakrainica Skipp, more detail and compares the foraminiferal zonation Holocomb, and Gutschick, Calcisphaera laevis William- with the megafaunal scheme established for that area. son, and Latiendothyra. It is also characterized by the decline of Ohernyshinella and Rectoseptaglomospira- nella. This assemblage occurs mostly in the lower third DISTRIBUTION, COMPOSITION, AND CRITERIA FOR RECOGNITION of the Mission Canyon Limestone in southeastern Idaho, western Wyoming, and Montana. The foraminiferal zones recognized in this study are Zone 9 is characterized by numerous T wberendothyra part of a 19-zone system originally established on (T. tuberculata (Lipina)) and by the acmes of Spino- European and Asiatic faunal successions (Mamet, endothyra spinosa (Chernysheva), S. paracostifera 1965; Mamet, Mortelmans, and Sartenaer, 1965; Le- (Lipina, in Lebedeva and Grozdilova), S. bellicorfa grand, Mamet and Mortelmans, 1966; Mamet and Eeit- (Malakhova), and Carbonella. Tournayella, Septa- linger, 1969). Zones 1 through 5 in this scheme are tournayella^ Septaglomospiranella, and Septabrunsiina Upper Devonian (upper Famennian) and will not be are also present. Eoforschia, Tetrataxis, Endothyra of discussed here. The earliest Tournaisian zone in the the group E. ? nordvikensis Lipina, Latiendothyra lati- type locality of the Tournaisian is Zone 6 (Legrand, spiralis (Lipina), and Endothyra of the group F, ? Mamet, and Mortelmans, 1966). The Tournaisian- prisca Eauzer-Chernoussova and Eeitlinger appear for Visean boundary is between Zones 9 and 10, and the top the first time. "Endothyra" (?) trachida Zeller is com of the Visean is the top of Zone 16s. Zones 17,18, and 19 mon. The zone also marks the appearance of Ca7-ci- are Namurian; only the lower part of the Namurian sphaera pachysphaerica (Pronina). This assemblage is was observed in the present study. found near the middle of the Mission Canyon Limestone Mamet and Skipp (1969) have already summarized in southeastern Idaho and Montana and near the middle the distribution of 107 taxa used in distinguishing of the Madison Limestone of central Wyoming. zones in the Mississippian of North America and have Zone 10 is marked by an outburst of GrloboendothyrEarlandia (E. It is probably synonymous with Plectogyra Zeller 1950, which has minima, (Birina)), ParacaHgeUa, Tufoeritina, CcHci- priority. However, the wall structure cannot be determined on ZellT's type material owing to recrystallization. Moreover, Plectogyra has sphaera, Vicinesphaem, Bisphaera, and "Radio- been used by its original author to include about 10 different endothyroid sphaera" The scarcity of plurilocular forms does not genera. 330-481 69 3 E14 CONTRIBUTIONS TO PALEONTOLOGY
ZONE RANGES OF FORAMINIFERA
Post- 18
18
17
16s
16i
15 < 1
i 14 i >
13
(12)
i i 11
j 45 4 < i 10 44
38 39 40 41 42 43 1 1 9 4 31 ' r lit. 26 27 28 29 30 32 33 34 35 36 37 8 < I 1 » 1 I
23 24 2~5 4 1 i i i i 1 7
11 12 13 21 Pre- 16 17 7
123456789 10 14 15 18 19 20 22 1. Brunsia emended 20. &. pHmaeva (Rauzer-Chernoussova, in 35. RANGES OF FORAMINIFERA ZONE 89 90 91 92 Post- 18 84 86 18 85 87 17 79 80 81 82 83 16s 74 75 76 77 78 71 72 73 15 64 65 66 67 68 69 70 14 60 62 63 13 53 54 55 56 57 58 59 61 (12; EXPLANATION + Last occurrence 11 48 51 Common occurrence 10 Acme 52 Rare occurrence First appearance ? Questionable occurrence 47 Pre 7 51. Archaediscus of the group A. chernous- 63. E. utahensis (Zeller) 78. Pseudoendothyra of the group P. sovensis Mamet 64. bilayered CHmacammina sp. kemenskensis Rozovskaia 52. Archaediscus of the group A. krestovni- 65. bilayered Gribrostomum sp. 79. Asteroarchaediscus sp. kovi Rauzer-Chernoussova 66. Endothyranopsis crassa (Brady) 80. A. baschkiricus (Krestovnikov end 53. Gribrospira 1 sp. 67. Globoendothyra of the group G. globulus Teodorovitch) 54. Endothyranopsis compressa (Rauzer- (d'Eichwald) 81. A. rugosus (Rauzer-Chernoussova) Chernoussova and Reitiinger) 68. Palaeotetetularia of the group P. longi- 82. Globivalvulina sp. 55. Eoendothyranopsis pressa (Grozdilova, septata Lipina 83. Ammovertellal sp. in Lebedeva) 69. "Eostaffella" discoidea (Girty) 84. Eostaffellina sp. 56. E. rara (Grozdilova, in Lebedeva) 70. Hedraites sp. 85. Millerella sp. 57. E. scitula (Toomey) 71. NeoarcJiaediscus sp. 86. Eosigmoilina sp. 58. Globoendothyra of the group G. tomiU- 72. Palaeonubecularia sp. 87. Hemiarchaediscus sp. ensis (Grozdilova) 88. Lipinella sp. 59. Omphalotis sp. 73^ Trepeilopsis sp. 89. Bradyina of the group B. cribrostomMta 60. "EoendotJiyranopsis" (?) banffensis (Mc- 74. Helicospirina sp. Rauzer-Chernoussova and Reitlinge" Kay and Green) 75. Neoarchaediscws incertus (Grozdilova 90. Eoschubertella sp. 61. Eoendothyranopsis of the group E. and Lebedeva) 91. Eostaffella of the group E. acutissi*na ermakiensis (Grozdilova, in Lebedeva) 76. N. gregorii Dain, in Grozdilova Kireeva 62. E. macro, (Zeller) 77. Planospirodiscua sp. 92. Pseudostaffella sp. fauna not known in the area of this report. Zones 19-21 undifEerentiated in this report and included in Zone post-18. E16 CONTRIBUTIONS TO PALEONTOLOGY Canyon Limestone in southeastern Idaho, western cammina appear for the first time. This assemblage is Wyoming, and Montana and in the Bull Eidge Mem poorly represented in samples from near the middle of ber (Sando, 1968) of the Madison Limestone of central the Monroe Canyon Limestone in southeastern Idaho Wyoming. but is well-represented in the Upper Mississippian of Zone 11 is characterized by the acme of Eoendothy- south-central Idaho and Alberta. ranopsis spiroides (Zeller) and abundant Globoen- Zone 16i is marked by the first appearance of Neo dothyra and Eoforschia. The first keeled Eostaffella archaediscus, rarefaction of Endothyranopsis, and ex appears here, and Stacheia and Stacheoides are also tinction of Eoendothyranopsis. It is also characterized present. Toumayella s.s. is rare. This assemblage occurs by keeled Eostaffella, and "Eostaffella" discoidea Girty. in the upper third of the Mission Canyon Limestone in "Glomospira" Hedraites, Trepeilopsis, Palceonube- southeastern Idaho, western Wyoming, and Montana cularia, and numerous Endothyra s.s. are also present. and in the Bull Eidge Member of the Madison Lime Globoendothyra is rare. Like Zone 15, this assemblage is stone in central Wyoming. poorly represented near the middle of the Monroe Can Zone 12 includes a fauna similar to that of Zone 11 yon Limestone in southeastern Idaho but is well-repre but can be distinguished by the outburst of a new sented in the Upper Mississippian of south -central species of Eoendothyranopsis of the group E. spiroides Idaho and Alberta. (Zeller) and the abundance of Koninckopora and mon- Zone 16s is characterized by the coexistence of Archae^ olayered Palaeotextularia. The Zone 12 assemblage was discus of the groups A. krestovnikovi Eauzer-Chernous not encountered in this study; it is present in the Salter sova and A. chernoussovensis Mamet and abundant Member of the Mount Head Formation of Alberta, Neoarchaediscus (N. gregorii Dain, in Grozdilova and where it occupies a stratigraphic position that coincides N. incertus Grozdilova and Lebedeva)). Planospiro- with part of the post-Madison hiatus which character discus becomes an important and characteristic faunal izes the northern Cordilleran region in the United marker. Endothyra ss. is abundant. There is an outburst States. of Pseudoendothyra of the group P. kemenskensis Zone 13 is marked by the extinction of Eoendothy Eozovskaia. Helicospirina, the ancestor of Globival- ranopsis spiroides (Zeller) after a short concurrent in vulina, is also present. Koninckopora becomes' extinct terval with Eoendothyranopsis pressa (Grozdilova, and Endothyranopsis crassa (Brady) practically dis in Lebedeva), E. rara (Grozdilova, in Lebedeva), E. appears. This assemblage occurs near the middle of the scitula (Toomey), and Endothyranopsis compressa Monroe Canyon Limestone of southeast Idaho. (Eauzer-Chernoussova and Eeitlinger). Propermodis- Zone 17 is marked by an outburst of Asteroarchaedis- cus is also present. There is an outburst of Archaediscus cus (A. l>aschkiricus (Krestovnikov and Teodo^ovitch) (A. krestovnikovi Eauzer-Chernoussova and A. cher- and A. rugosus (Eauzer-Chernoussova)) mixed with noussovensis Mamet groups). Cribrospiral and Om- numerous Neoarchaediscus. Globivalvulina s.s. appears phalotis appear for the first time. This assemblage for the first time. This assemblage is found in tH upper occurs in the Little Flat Formation in southeastern third of the Monroe Canyon Limestone of southeastern Idaho and northeastern Utah. Idaho, near the top of the Brazer Limestone (as used by Zone 14 is recognized on the acme of Eoendothyra Mullens and Izett, 1964) of northern Utah, in the Ams- nopsis of the group E. ermakiensis (Grozdilova, in den Formation of western Wyoming, and in the Big Lebedeva), represented by E. macro, (Zeller) and E. Snowy Group of southwestern Montana. utahensis (Zeller), and abundant Stacheia and Stache Zone 18 includes Archaediscidae similar to those in oides. Brunsia is commonly abundant (Brunsia facies) Zone 17 but is marked by the outburst of GloMwrlviilina and "Eoendothyranopsis"* 'ban-ffensis (McKay and and the first appearance of Eostafiellina. This assem Green) is normally present. This assemblage is found blage occurs near the top of the Monroe Canyon Lime in the Little Flat Formation and the lower third of the stone of southeastern Idaho, in the Amsden Formation Monroe Canyon Limestone in southeastern Idaho and of western Wyoming, and in the Big Snowy G~oup of northeastern Utah. southwestern Montana. Zone 15 includes the acme of Eoendothyranopsis and Zone post-18 includes Zones 19, 20 and 21 of Mamet is marked by the appearance of Endothyranopsis (1968b), which are not differentiated in this report. It crassa (Brady) mixed with E. compressa (Eauzer- includes the Namurian Eosigmoilina-Hemiarchaediscus, Chernoussova and Eeitlinger). It is characterized by Lipinella-MUlerella, and Eoschubertella-Pseudostaf- the acme of Globoendothyra of the groups G. globidus fella-Bradyina cribrostomata assemblages. The position (d'Eichwald) and G. tomUiensis (Grozdilova). Bi- of Zone 19 is uncertain with respect to the Missis^ippian- layered Palaeoteaetularia, Cribrostomum, and Clima- Pennsylvanian boundary as defined in the midcontinent CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E17 region. Zone 19 is certainly younger than the highest Postdepositional changes formation of the Chester Series (Grove Church Forma Recrystallization associated with extensive dolomiti- tion of Swann, 1963) in Illinois and the Pitkin Lime zatiou is the principal hindrance to precise taxonomic stone in Arkansas. There is an apparent hiatus between determination of foraminifers. When wall structures these formations and the overlying Pennsylvanian, are severely altered, determination becomes hazardous, which begins with Zone 20. Zone 19 could be regarded even on a generic basis. All samples determined in this either as uppermost Mississippian or as lowermost study are of slightly recrystallized limestone. Postde Pennsylvanian. Recent discovery of a continuous se positional changes are responsible for the lack of f orara- quence of foraminiferal faunas across this boundary in iniferal determinations in the Brazer Dolomite and south-central Idaho may provide a solution to this prob the scarcity of determinable samples in the Madison lem. We currently favor regarding Zone 19 as upper Limestone of central Wyoming. Age determinations on most Mississippian because of the greater similarity of these strata and other similar facies must depend on Zone 19 faunas to Zone 18 faunas. Zone post-18 has been fossils less susceptible to destruction by recrystalliza- identified in the Amsden Formation of western and tion. Corals are usually the most lasting of these. south-central Wyoming. COMPARISON OF ZONATION SCHEMES LIMITATIONS One of the principal reasons for undertaking this Available evidence indicates that the distribution of study was to check the internal consistency of the meg^.- Foraminifera permits a more precise correlation of the f aunal zones already established in the northern Ccr- Lower Carboniferous than megaf aunal groups on a con dilleran region by means of an independent biostrati- tinent-wide or intercontinental scale. Although this may graphic system. Among the questions posed are: (1) be partly due to more detailed study of the Foraminif Is the composite superposition of megafaunal zones era in a global perspective in recent years, it also seems erected on widely separated sequences verified by fora to reflect the fundamentally more cosmopolitan aspect miniferal determinations on the same samples? (2) Do of Early Carboniferous Forminifera. Endemism is quite foraminiferal determinations confirm the identifica evident in some Early Carboniferous foraminiferal fau tion of megafaunal zones in various parts of the north nas, but there are still many more widely distributed ern Cordilleran region, particularly in different depod- genera and species than are known among the corals tional provinces? (3) Are the boundaries of the and brachiopods. Despite this advantage, the foramini- megafaunal zones coincident with the boundaries of fers are subject to the following limitations. (See also foraminiferal zones? (4) Do foraminiferal determina discussion by Mamet and Skipp, 1969.) tions confirm the hiatus between Madison and post- Madison strata inferred from megafaunal distribution ? Influence of environment of deposition (5) Are there any gaps in the record that have not beun Microfacies found particularly suitable for foram recognized by megafossils ? We believe that this study iniferal study are biosparite and biomicrite containing has given reasonable answers to most of these ques a minimum of terrigenous debris. Moderately shallow tions. Pertinent data for comparison of the two zoral water, indicated by association with girvanellid and schemes are given in figure 6, which shows the meg"v dasycladacean algae, is also a favorable factor. The in faunal and microfaunal zone identifications of 105 fluence of depositional environment is particularly evi samples from 20 stratigraphic sections. dent in the Lower Mississippian (Tournaisian), where INTEGRITY OF SUPERPOSITION foraminiferal correlations are commonly difficult. An Without exception, foraminiferal analysis rever-ls example in the present study is the difficulty in precise the same order of superposition established on the basis correlation of the lower part of the Lodgepole Lime of megafaunal zonation of the same samples. Although stone (Paine Shale Member). Foraniinifers are gener there are overlaps in zone boundaries, no reversals in ally rare in this facies, apparently because of high ter the expected sequence of zones are found. TH rigenous sediment content and perhaps also because of following equations between the two zonal schemes are greater depth. Another example is the difficulty in recog established. nizing a Mississippian-Pennsylvanian boundary because 1. Unzoned beds of Pennsylvanian age equal Zone of the scarcity of foraminifers in lowermost Pennsyl post-18. vanian terrigenous rocks of the midcontinent region. 2. Zone post-K equals Zone unknown (no foramini Such hindrances make detailed correlation of these beds fers found). difficult on the basis of foraminiferal evidence. 3. Zone K equals Zones 16s-18. E18 CONTRIBUTIONS TO PALEONTOLOGY CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E19 4. Zone F equals upper part of Zone 14 and Zone 15. dence from the Black Mountain and Sacajawea Peak 5. Zone E equals Zone 13 and lower part of 14. sections indicates that there is an overlap in the lower 6. Zone pre-E equals Zone 13 and lower part of 14. boundaries of these zones (pi. 1 and fig. 6). Samples 7. Zone D equals Zones 10 and 11. 20079 and 20085 from the upper part of Zone d cor- 8. Zone C2 equals Zones 8 and 9. tain a rich Tuberendothyra tuberculata faunule (Zone 9. Zone Ci equals Zone 7 and lowermost part of 8. 8), which is normally found in beds assigned to Zore 10. Zones A and B equal Zone pre-7. C2. A similar situation is found in sample 20666 from 11. Zone pre-A equals Zone unknown (no foramini- the uppermost part of Zone Ci at Sacajawea Peal*, fers found). where determinable foraminifers do not indicate whether the faunule belongs to Zone 7 or to Zone 8. IDENTIFICATION IN DIFFERENT DEPOSITIONAL More rapid evolution of the Foraminifera permit the PROVINCES recognition of two distinct zones (8 and 9) in the niegr,- Megafaunal studies summarized by Sando (1967b) f aunal Zone C2 interval of the lower part of the Mission indicate that there was a marked differentiation of the Canyon Limestone. Two foraminiferal zones (10 and northern Cordilleran region into cratonic and miogeo- 11) can also be recognized in Zone D (upper part of synclinal areas during Late Mississippian time. Corre Mission Canyon Limestone), but these zones are not lations established on the basis of megaf aunas indicate clearly separable in about half of the samples from this that the upper part of the Monroe Canyon Limestone interval. of the migeosynclinal Idaho province is the temporal Poor microfacies for foraminifers in the Little Flp.t equivalent of part of the cratonic Amsden Formation Formation make it difficult to draw a precise boundary of western "Wymoing and the Big Snowy Group of between Zones 13 and 14. Samples identified megafau- southwestern Montana. The discovery of Zone 17 and nally as Zone pre-E and Zone E contain similar foram 18 foraminiferal assemblages in each of these units iniferal assemblages. The base of Zone 14 appears confirms the previous identifications of Zone K. Al to occur in the upper part of Zone E, but many of tH though the Amsden and Big Snowy are generally poor samples from Zone F of the Monroe Canyon Limestor^ facies for foraminifers, additional collecting might contain good Zone 14 foraminiferal assemblages. Zor^- prove even more rewarding for establishing relation F also clearly includes all of Zone 15. ships with sequences in the Idaho province. Zone pre-K of the Monroe Canyon Limestone yielded Another noteworthy example of interprovincial cor a meager assemblage of foraminifers identified as Zone relation corroborated by the foraminiferal studies is the 16i, which is much better represented in samples from confirmation of Zone D in the Bull Ridge Member south-central Idaho and Alberta than in the samples (Sando, 1968) of the Madison Limestone of the Wyo examined in the present study. More work is necessary ming province by discovery of Zone 10 and 11 assem to establish precise zonal boundaries on both mega- blages there. Also, the presence of Zone C2 has been faunas and microf aunas in this part of the section. confirmed in the lower part of the Madison Limestone The outburst of many foraminiferal taxa in middle at Sinks Canyon on the basis of a Zone 9 foraminiferal and late Chester time makes it possible to recognize assemblage. three zones (16s, 17, and 18) corresponding to mega CORRELATION OF ZONE BOUNDARIES faunal Zone K of the Monroe Canyon Limestone, Am^- den Formation, and Big Snowy Group. The base of Zone None of the megafaunal zones is precisely equivalent K coincides with the base of Zone 16s in all but one to one foraminiferal zone. If the boundaries between sample (18708), which may include an equivalent to tH megafaunal zones were coincident with boundaries upper part of Zone 16i. The top of Zone K appears to between foraminiferal zones, one might suspect numer coincide with the top of Zone 18, but the lack of foram ous hiatuses in the sequence. In the Kinderhook iniferal control in Zone post-K prohibits a final Series (lower part of the Lodgepole Limestone and judgment. lower part of the Madison Limestone), foraminifers Zone post-K is so poorly represented in the area stud are too rare and evolved too slowly for precise zonation, ied that few samples are available, and the samples that so the entire interval is included in a single zone (Zone were examined contained no determinable foraminifers. pre-7). Corals, brachiopods, and conodonts evolved This zone is provisionally correlated with Zone post-T.8 more rapidly, permitting recognition of three zones on the basis of its position above the Zone 18 assemblage. (pre-A, A, and B) in the same interval. Zone post-18 also includes samples (16211,21725,2172P) The upper part of the Lodgepole is generally char that are dated as Early Pennsylvanian on the basis of acterized by Zone d and Zone 7 assemblages, but evi brachiopods. E20 CONTRIBUTIONS TO PALEONTOLOGY POST-MADISON HIATUS tribute significantly to more precise determination of the maximum timespan of the post-Madison hiatus in Dutro and Sando (1963a, fig. 6) postulated the exist the Montana and Wyoming provinces. However, the ence of a significant hiatus between the Lodgepole universal absence of foraminiferal Zone 12 indicates Limestone and the overlying Little Flat Formation in that the minimum timespan of the hiatus is the Late southeastern Idaho and northeastern Utah. Sando Mississippian interval equivalent to the upper part of (1967b) presented evidence that this hiatus was due to a the Salem Limestone in the type Mississippian sequence. widespread episode of post-Madison epeirogenic emer gence in the northern Cordilleran region. The main ABSENCE OF OTHER GAPS IN THE RECORD basis for this interpretation in the Idaho province (southeastern Idaho and northeastern Utah) is the ab Aside from the foraminiferal zones missing between sence of Zones D, C2, and possibly a part of Ci from the Madison and post-Madison intervals, no other stratigraphic sections in the Deep Creek Mountains, the hiatuses were detected in the sequence, a conclusion Chesterfield Kange, and Old Laketown Canyon, where reached previously by megafaunal analysis. This con Zone pre-E rests on Zone Ci. In the Montana and Wy clusion must, of course, be qualified according to the oming provinces, the interpretation rests on the pres resolving power of the zonation scheme. Francis and ence of widespread karst features at the top of the Mad Woodland (1964, table 1) estimated that the Ifississip- ison Group and the absence of Zone pre-E and pian spanned approximately 25 million years which E assemblages. were about equally divided between Early ITississip- Foraminiferal data compiled in the present study not pian (Kinderhook and Osage) and Late Misrssippian only confirm the interpretation made on megafaunal (Meramec and Chester) divisions. Inasmucl as four evidence but also permit a more precise evaluation of foraminiferal zones are recognized in the Early Missis the time span of the erosional interval in the Idaho prov sippian interval, the average timespan of a zone during ince. At Little Flat Canyon in the Chesterfield Kange, that interval is approximately 3 million yeara In the five foraminiferal zones are missing from the sequence Late Mississippian interval, more rapid evolution of between the Lodgepole Limestone and the Little Flat the Foraminifera permits recognition of 10 zones. Formation. At Old Laketown Canyon, no control was Here the average timespan of a zone is decreased to obtained on the lower part of the Little Flat Formation, slightly more than 1 million years. Consequently, gaps but the highest Lodgepole beds there were identified of less than 3-million-years duration in the earTy Missis as Zone 7, the same interval recognized in the upper sippian or less than 1-million-years duration r\ the late part of the Lodgepole at Little Flat Canyon. Correla Mississippian could not be detected by the zonation tion of these missing zones with the type Mississippian scheme. indicates that the hiatus represents all of Keokuk, INTRACONTINENTAL AND INTERCONTINENTAL Warsaw, and Salem time. CORRELATIONS Evaluation of the timespan of the post-Madison The foraminiferal zones recognized in the northern hiatus is more difficult in the Montana and Wyoming Cordilleran region have been identified by TTamet in provinces. In the Sweetgrass arch area of north-central the type Mississippian, the Mississippian of western Montana and in the Sawtooth Range of northwestern Canada, and in standard Carboniferous sequences in Montana, the Madison is overlain disconformably by Europe. Mamet and Skipp (1969) have summarized the Mesozoic rocks. Elsewhere in the Montana province the temporal significance of the foraminiferal zones as Madison is overlain disconformably by rocks of Late applied to correlation of the North American Mississip Mississippian age included in the Big Snowy Group or pian with western European Carboniferous stand Amsden Formation or by the Pennsylvanian part of the ards. However, the present study deals in nmre detail Amsden. In the Wyoming province, the Madison is with specific formations in the northern Cordilleran overlain disconformably by rocks of Late Mississippian region. Consequently, it is desirable to discuss briefly age in the Amsden Formation or by the Casper Forma tion of Pennsylvanian and Permian age. Inasmuch as the correlations of these units with the type Mississip the lowest beds of the Amsden Formation (Darwin pian and with European time-stratigraphic divisions. Sandstone Member) and Big Snowy Group (Kibbey The essential conclusions of the following discussion Sandstone) are unfossiliferous, the age of the oldest are summarized in figure 7. post-Madison Missdssippian strata has been estimated LODGEPOLE LIMESTONE by means of lithostratigraphic correlation with beds dated by fossils in the Idaho province (Sando, 1967b). Two foraminiferal assemblages are recognizable in Foraminiferal data compiled in this study do not con the Lodgepole Limestone, the Zone pre-7 assemblage CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES BELGIANCARBONIFEROUSDIVISIONS SYSTEMS(NORTHUSAGE)AMERICAN CORDILLERANZONESMEGAFAUNAL SYSTEMS(INTERNATIONALUSAGE) FORAMINIFERALGLOBALZONES NORTHAMERICANSERIES EUROPEANSTAGES TYPEMISSISSIPPIAN CORDILLERAN FORMATIONS FORMATIONS PENNSYL- Caseyville Formation VANIAN R Post- 18 H Post-K WW^^ - UPPER CARBONIFEROUS Namurian Kinkaid Limestone E 2 18 Clore Limestone I r ^"~"'\J-FormationBullAmsden(lowerpart)RidgeMember Menard Limestone & EI 17 tn K Glen Dean Limestone \ h "^Renault Formation \ $ ° V3c, 1 < 5 16i Pre-K <* Aux Vases < .s? ;* Sandstone |^ o nroe 1 / CQ V3b 15 Ste. Genevieve F Limestone Lime1Vstone° V1 /J\ V3a 14 Visean 1 E St. Louis Limestone Ljt1 tie Flat <^ / Z < V2b 13 Formation ^ 0. Meramec Pre-E Q- tO V) V2a 12 LOWERCARBONIFEROUS CO CO S Vlb 11 Salem Limestone r D r Via 10 j> Warsaw <^~ Limestone r MadisonLimestones- ^~^./~~~-^~ J Mission j Canyon Tn3c(b) 9 ^ Limestone 0) C 2 Keokuk Limestone ^ 00 (0 in Tn3a 8 O ) Tournaisian Woodhurst 0) Limestone Tn2b 7 Ci Burlington Limestone c Member E (upperpart) B Paine Shale Kinderhook Tn2a I] Pre- A £ Member 7 a c^ottonwood Canyo n Tnlb Pre-A T3 Member O (upper part) FIGURE 7. Correlation chart showing inferred relationships of faunal zones, principal Euro pean and American time-stratigraphic divisions, and Cordilleran and type Mississippian formations. E22 CONTRIBUTIONS TO PALEONTOLOGY found in the Paine Shale Member and the Zone 7 as burg Limestone (restricted) of Stockdale (1939), and semblage of the Woodhurst Limestone Member. Scar the lower and middle parts of the Salem Limestone in city of foraminifers in the Paine Shale Member makes Illinois are characterized by the outburst of Globoen- comparison with other foraminiferal sequences diffi dothyra and Endothyranopsis^ evolved Tetrataxinae, cult. However, a similarly poor microfacies, in which and the first Archaediscidae, which mark there assem only calispherids and Bisphaera are common, is also blages. This radical change in the foraminiferal faunas found in the type Kinderhook Series and in the Banff is conspicuous at the lowermost level of the "7isean in Formation of Alberta. An early Tournaisian, pre-Burl- Belgium in the "Marbre noir de Dinant" (Via) and ington age is indicated, but the foraminifers are here "Dolomie de Sovet" (Vlb) (Mamet, 1965). of no value in identifying the base of the Lower Car Foraminiferal Zone 12, which corresponds to the up boniferous. Identification of this datum in the Lodge- per part of the Salem Limestone, has not been found in pole depends mainly on interpretation of conodont any of the samples studied. Evidently, the timespan of faunas in the Cottonwood Canyon Member. this zone coincides with at least a part of the period of The foraminiferal assemblage (Zone 7) of the Wood- post-Madison uplift that occurred throughout most of hurst Limestone Member is characteristic of the upper the northern Cordilleran region. This zone, represented most Kinderhook and the Burlington Limestone of the in Alberta (Salter Member of the Mount Head Forma type Mississippian and of the upper part of the Banff tion in its type locality), is of early middle Visean Formation and lowermost part of the Livingstone and (V2a) age. Pekisko Formations of Alberta. This assemblage is en LITTLE FLAT FORMATION countered in the U.S.S.R. above the Bisphaera beds and Although most of the beds in the Little Flat Forma constitutes the Chemysliinella glomiformis Palaeo- tion are not particularly good microfacies for foramin spwoplect&irwmna, tchernyshinensis assemblage zone of ifers, elements of two assemblages (Zones 13 and lower Russian authors. Zone 7 is also known in the type sec part of Zone 14) have been found. These assemblages, tion of the Tournaisian (Legrand and others, 1966) and particularly characterized by abundant Endothyranop- in the Calcaire de Landelies (Tn2b) of Belgium. The sis and KonincJcopora,, occur in the St. Louis Limestone presence of a Zone 8 assemblage in the upper part of of the midcontinent region and are also knov7n in the the Woodhurst Limestone Member at some localities Loomis and Marston Members of the Mount Head For suggests that a lowermost Keokuk equivalent could also mation in Alberta. Zone 13 is well represented in the be present near the top of the Lodgepole. Calcaire de Lives and in. the Banes Inferieurs d'Anhee MISSION CANYON LIMESTONE of Belgium, where the outburst of Endottiyranopsis compressus is conspicuous. Zone 14 is poorly known in Four foraminiferal assemblages can be distinguished the Belgian sequences, but it is well displayed in the in the Mission Canyon Limestone, the Zone 8 and 9 as Bristol area of England (upper part of S2). semblages in the lower part, and the Zone 10 and 11 as semblages in the upper part. The Osage-Meramec MONROE CANYON LIMESTONE boundary, which correlates with the Tournaisian-Visean The Monroe Canyon Limstone represents a consider boundary, occurs between Zones 9 and 10. able interval of Late Mississippian tune. Its foraminif The lower Mission Canyon assemblages (Zones 8 and eral sequence can be divided into six zones tl at range 9), characterized by "spinose" endothyroads, are poorly in age from late Meramec through most of the. Chester. developed in the Keokuk Limestone of the midconti- The lowest beds of the Monroe Canyon Limestone are nent region but are well developed in the Shunda For characterized by a continuation of the Zone 14 assem mation and part of the Turner Valley Formation of blage found in the upper part of the Little Flat Forma Alberta. These assemblages are also characteristic of tion. This lowermost Monroe Canyon is correlated with the Chikman-Kizel interval in the U.S.S.R. Although the upper part of the St. Louis Limestone and the these zones are poorly exposed in the type locality of lowermost part of the Ste. Genevieve Limestor?- (of the the Tournaisian, they are present in the Calcaire d'Yvoir (Tn3a) and the Calcaire de Leffe (Tn3c) in the type section in Missouri). Dinant synclinorium of Belgium. The Zone 15 assemblage, found near the middle of The upper Mission Canyon assemblages (Zones 10 the Monroe Canyon, represents the highest beds of and 11), also found in the Bull Ridge Member of the Meramec age in the formation. This assemblage occurs Madison Limestone of central Wyoming, have been ob in the upper part of the type Ste. Genevieve (Missouri) served in the Salem Limestone of the midcontinent and extends into beds assigned to the Ste. Ger,evieve in region. In particular, the Warsaw Limestone, Harrods- Illinois and Kentucky. The upper part of the S'^e. Gene- CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E23 vieve of Illinois and Kentucky contains elements of the missing, the Mississippian-Peiinsylvanian boundary cr ,n Zone 16i assemblage and therefore extends across the be drawn between Zones 18 and post-18 of the foram Meramec-Chester boundary, which is placed at the top iniferal scheme. of Zone 15. Zones 15 and 16i are represented in the upper BIG SNOWY GROUP Visean (V3b and lower part of V3c) of Belgium. The Zone 15 assemblage is well developed in the Carnavon The only determinable foraminiferal samples from Member of the Mount Head Formation of Alberta. the Big Snowy Group are from beds near the middle of The upper third of the Monroe Canyon Limestone this unit in the Baldy Mountain section of southwestern contains three zones of Chester age and straddles the Montana (pi. 1). These samples are associated with Visean-Nainurian boundary. The abundance of Neo- megafossils determined as Zone K. The foraminiferal (trchaediscus and occurrence of Planospirodiscus in assemblages are characteristic of Zones 17 and 18, indi Zone 16s indicates equivalence with the Paint Creek- cating a Chester (Glen Dean-Kinkaid) age for this Golconda interval of the midcontinent region and the part of the Big Snowy. middle part of the Etherington Formation of Alberta. Zone 16s is also found in the uppermost Visean of CONCLUSIONS Belgium (upper part of V3c) and England (upper P2) It has been said that corals and brachiopods are too (Mamet, Hottinger, and Choubert, 1967). Zones 17 and facies sensitive to be practical for chronostratigrapl y 18 are characterized by the outburst of AsteroarcJiae- even within a basin of deposition. This viewpoint is discuS) G-lobivalvulina s.s., and Eostaffellina. Such probably too pessimistic, at least in regard to correla early Namurian fossils are observed in the Glen Dean- tions within the shelly carbonate facies. Comparison of lower Kinkaid interval of the midcontinent region and the coral-brachiopod zonation scheme established for the are also present in the upper part of the Etherington Mississippian of the northern Cordillera with a foram Formation of Alberta. Zone 17, which coincides with the iniferal scheme that has been tested on a global baris lower Eumorphoceras Zone (E± and lower E2) of west results in remarkably consistent answers with regard ern Europe, is often called uppermost Visean in the to intra- and extra-basinal correlations. U.S.S.R. There are few modifications at that level in the Time correlations based on foraminiferal faunas Eostaffellidae and Pseudoendothyridae; the first out confirm the broad chronostratigraphic relationships burst of EostaffeUina protvae occurs above Zone 17 in established between the northern Cordillera and the the upper part of E2 in the Protva Formation of the type Mississippian on the basis of rnegafaunas. More U.S.S.R. over, a higher degree of cosmopolitanism in the foram AMSDEN FORMATION iniferal faunas permits more precise correlations with Although the determinable foraminiferal samples the type Mississippian and with standard Carbonifer from the Amsden Formation are rather limited both in ous sequences in western Europe. number and in geographic distribution, several signifi Although the resolution of the foraminiferal zores cant conclusions can be derived from them. The Amsden is generally finer than that of the megafaunal zor^ samples clearly indicate a Late Mississippian age for the tested, corals and brachiopods evolved more rapidly lower part of the formation in western Wyoming and than the foraminifers in some parts of the Lower Cr.r- suggest a means for distinguishing the Mississippian- boniferous and, hence, are locally more useful for zora- Pennsylvanian boundary on the basis of foraminiferal tion. The greater susceptibility of the foraminifers to assemblages. alteration or destruction by recrystallization leaves no Five of the Amsden samples are from the middle or alternative but to use megafaunas in some rock se the lower half of the formation associated with mega- quences. Mutual calibration of the two zonal schemes fossils determined as Zone K (pi. 1). These samples enhances the value of both for biostratigraphic studies. contain foraminiferal Zone 17 and Zone 18 assemblages, REFERENCES CITED which are found in the upper Chester (Glen Dean-Kin- Armstrong, A. K., 1958, Meramecian (Mississippian) endothyrid kaid) of the midcontinent region. fauna from the Arroyo Penasco Formation, northern and Three samples are from beds near the middle of the central New Mexico: Jour. Paleontology, v. 32, no. 5, p. formation that have been determined as Pennsylvanian 970-976, pi. 127, 2 figs. on the basis of megafossils. These samples are all re 1967, Biostratigraphy and carbonate facies of the Mis sissippian Arroyo Pefiasco Formation, north-central New ferred to forminiferal Zone post-18. These findings Mexico: New Mexico Bur. Mines and Mineral Resources suggest that in sections where the post-K Zone is Mem. 20, 79 p., 12 pis. 45 figs., 4 tables. E24 CONTRIBUTIONS TO PALEONTOLOGY Dutro, J. T., and Sando, W. J., 1963a, New Mississippian for Mamet, B. L., and Skipp, Betty, 1969, Lower Carboniferous mations and faunal zones in Chesterfield Range, Portneuf calcareous Foraminifera preliminary zonation and strati- quadrangle, southeast Idaho: Am. Assoc. Petroleum Geolo graphic implications for the Mississippian of Ncrth Amer gists Bull., v. 47, no. 11, p. 1963-1986,6 figs. ica: Internat. Cong. on Carboniferous Stratigraphy and 1963b, Age of certain post-Madison rocks in southwestern Geology, 6th, Sheffield, England, Sept. 1967, Con'ote rendu Montana and western Wyoming, in Short papers in geol (in press). ogy and hydrology: U.S. Geol. Survey Prof. Paper 475-B, p. Moore, R. C., 1948, Paleontological features of Mississippian B93-B94, 2 figs. rocks in North America and Europe: Jour. Geology, v. 56, Francis, E. H., and Woodland, A. W., 1964, The Carboniferous no. 4, p. 373-402, 17 figs. period, in The Phanerozoic time scale a symposium: Geol. Mudge, M. R., Sando, W. J., and Dutro, J. T., Jr., 19"2, Missis Soc. London Quart. Jour., v. 120 supp., p. 221-232, 1 fig., 2 sippian rocks of Sun River Canyon area, Sawtooth Range, tables. Montana: Am. Assoc. Petroleum Geologists Bnll., v. 46, Gordon, Mackenzie, Jr., 1964, Carboniferous cephalopods of no. 11, p. 2003-2018, 6 figs. Arkansas: U.S. Geol. Survey Prof. Paper 460, 322 p., 32 pis., Mullens, T. E., and Izett, G. A., 1964, Geology of the Paradise 96 figs., 11 tables. quadrangle, Cache County, Utah: U.S. Geol. Survey Bull. Gutschick, R. C., and Rodriguez, Joaquin, 1967, Brachiopod 1181-S, 32 p., 1 fig., 1 pi. zonation and correlation of Sappington Formation of west Parks, J. M., 1951, Corals from the Brazer formation (Mississip ern Montana: Am. Assoc. Petroleum Geologists Bull., v. 51, pian) of northern Utah: Jour. Paleontology, v. 25, no. 2, no. 4, p. 601-607,2 figs. p. 171-186, pis. 29-33, 3 figs. Hill, Dorothy, 1948, The distribution and sequence of Carbonif Rauzer-Chernoussova, D. M., and others, 1948, A synroosium of erous coral faunas: Geol. Mag., v. 85, no. 3, p. 121-148, 5 papers on the stratigraphy of the Lower Carboniferous on Foraminifera: Akad. Nauk SSSR Inst. Geol. Tr^dy, v. 62, 1957, The sequence and distribution of upper Palaeozoic Geol. Ser., no. 19, p. 1-243. [In Russian.] coral faunas: Australian Jour. Sci., v. 19, no. 3a, p. P42-P61, Rodriguez, Joaquin, and Gutschick, R. C., 1967, B-achiopods 1 fig. from the Sappington Formation (Devonian-Misslssippian) Klapper, Gilbert, 1966, Upper Devonian and Lower Mississippian of western Montana: Jour. Paleontology, v. 41, no. 2, p. 364- conodont zones in Montana, Wyoming, and South Dakota: 384, pis. 41-43, 7 figs., 4 tables. Kansas Univ. Paleont. Contr., paper 3, 43 p., 6 pis., 2 figs., Sandberg, C. A., and Klapper, Gilbert, 1967, Stratigraphy, age, 1 table. and paleotectonic significance of the Cottonwood Canyon Klepper, M. R., Weeks, R. A., and Ruppel, E. T., 1957, Geology Member of the Madison Limestone in Wyoming and Mon of the southern Elkhorn Mountains, Jefferson and Broad- tana: U.S. Geol. Survey Bull. 1251-B, 70 p., 5 fig:*. 3 tables. water Counties, Montana: U.S. Geol. Survey Prof. Paper Sando, W. J., 1960, Distribution of corals in the Madison group 292, 82 p., 8 pis., 6 figs., 5 tables. and correlative strata in Montana, western Wyoming, and Legrand, R., Mamet, B. L., and Mortelmans, G., 1966, Sur la northeastern Utah, in Short papers in the geological stratigraphie du Tournaisien de Tournai et de Leuze. sciences: U.S. Geol. Survey Prof. Paper 400-B, p. B225- Problemes de 1'etage Tournaisien dans sa localite-type: B227, 3 figs. Soc. Beige Geologic Bull., v. 74, p. 140-188. 1967a, Madison Limestone (Mississippian), Wind River, MoKay, W., and Green, Robert, 1963, Mississippian Foraminifera Washakie, and Owl Creek Mountains, Wyoming: Am. Assoc. of the southern Canadian Rocky Mountains, Alberta: Re Petroleum Geologists Bull., v. 51, no. 4, p. 529-557, 8 figs. search Council Alberta Bull. 10, 77 pp., 12 pis., 4 figs. 1967b, Mississippian depositional provinces in the north Mamet, B. L., 1962, Remarques sur la microfaune de Forami- ern Cordilleran region, in Geological Survey Research 1967: niferes du Dinantien: Soc. Beige G6ologie Bull., v. 70, no. U.S. Geol. Survey Prof. Paper 575-D, p. D29-D3P 3 figs. 2, p. 166-173. 1968, A new member of the Madison Limestone (Missis - 1965, Remarques sur la microfaune du "Marbre Noir de sippian) in Wyoming: Geol. Soc. America Bull., v. 79, no. 12, Dinant" (Via) : Soc. Geol. Belgique Annales, v. 88, Bull. p. 1855-1857, 2 figs. 5-6, p. 188-219. Sando, W. J., and Dutro, J. T., Jr., 1960, Stratigraphy and coral 1968a, The DevonianjCarboniferous boundary in Eurasia, zonation of the Madison group and Brazer dolomite in in Oswald, D. H., ed., Internat. Symposium on the Devo northeastern Utah, western Wyoming, and southwestern nian System, Calgary, Alberta, Sept., 1967: Calgary, Alberta Montana, in Wyoming Geol. Assoc. Guidebook, 15th Ann. Soc. Petroleum Geologists, v. 2, p. 995-1007. Field Cbnf., Overthrust belt of southwestern Wyoming and 1968b, Foraminifera, Etherington Formation (Carbonif adjacent areas : p. 117-126,1 pi. 3 figs. erous), Alberta, Canada: 'Canadian Assoc. Petroleum Geol Skipp, Betty, 1963, Zonation of calcareous Foraminifera in the ogists Bull., v. 16, no. 2, p. 167-179. Redwall Limestone (Mississippian) of Arizona [abs.]: Mamet, B. L., Mortelmans, G., and Sartenaer, P., 1965, Reflexions Geol. Soc. America Spec. Paper 73, p. 245-246. a propos du Calcaire d'Etroeungt: Soc. Beige Geologie 1964, Zonation of Mississippian rocks in Nortl American Bull., v. 74, no. 1, p. 41-51. Cordillera using Tournayellinae, calcareous Fcraminifera Mamet, B. L., Hottinger, L., and Choubert, G., 1967, Notes sur [abs.]: Geol. Soc. America Spec. Paper 76, p. 157.-153. le Carbonifere du jebel Ouarkziz; Etude du passage 1969, Foraminifera, in McKee, E. D., and Gutschick, du Viseen au Namurien d'apres les Foraniinif eres: Maroc R. C., History of the Redwall Limestone in northern Ari Service Geol. Notes et Mem. v. 27, no. 198, p. 7-21, pis., zona: Geol. Soc. America Mem. 114 (in press). 4 figs. Skipp, Betty, Holcomb, L. D., and Gutschick, R. C., 1966, Mamet, B. L., and Reitlinger, E., 1969, A foraminiferal zonation Tournayellinae, calcareous Foraminifera in Mississippian of the Lower Carboniferous of Europe: Voprosy Mikro- rocks of North America: Cushman Found. Foram. Re paleontologii (in press). search Spec. Pub. 9,38 p., 7 pis., 7 figs. CARBONIFEROUS ZONATION IN THE NORTHERN CORDILLERA OF THE UNITED STATES E25 'ockdale, P. B., 1939, Lower Mississippian rocks of the east- Zeller, E. J., 1950, Stratigraphic significance of Mississippian central interior [U.S.]: Geol. Soc. America Spec. Paper 22, endothyroid Foraminifera: Kansas Univ. Paleont. Contr. 248 p. [no. 7], Protozoa, art. 4,23 p., 6 pis. 3'vann, D. H., 1963, Classification of Genevievian and Chesterian 1957, Mississippian endothyroid Foraminifera from the (Late Mississippian) rocks of Illinois: Illinois Geol. Survey Gordilleran geosyncline: Jour. Paleontology, v. 31, no. 4, Kept. Inv. 216,91 p. p. 679-704, pis. 75-82,11 figs., 1 table. Foodland, R. B., 1958, Stratigraphic significance of Mississip pian endothyroid Foraminifera in central Utah: Jour. Paleontology, v. 32, no. 5, p. 791-814, pis. 99-103, 5 figs. INDEX [Italic ipage numbers indicate major references] Page acutissima, Eostaffetta...... E15 Page Cyathaxonia...... E9 Allan Mountain Limestone._...... 9,10 (Caenocyclus) sp., Pericydus. E9 tantiUa...... 7,9 alternatus, Echinoconchus...... (i,8,10 C alcaire de Landelies _ _.. 22 Cyrtina burlingtonensis...... 8,9 Ammovertetta sp.______...... 15 Calcaire de Leffe.___..... 22 Amplexus...... 9 Calcaire de Lives__ ...... 22 sp...... 7 Calcaire d'Yvoir____... 22 Amsden Formation....._____ 5,11,16,17, 19,20 Calcisphaera...... 13 dainae, Septaglomospiranetta...... 13,14 correlation with other units...... *S laevis...... 13,14 Darwin Sandstone Member, Amsden Forma Darwin Sandstone Member.._...... 20 pachysphaerica...... 13,14 tion__...... -...-...... 20 analoga, Leptagonia...... _...... 8,9 Camarotoechia...... 9 Deep Creek Formation_ .. 10 Ankhelasma...... 10 metattica...... 8 deminutivum, MetriophyUum...... 7,9 typicum...... 7 Canadiphyttum...... 10 dent uineata, Pseudopolygnathus...... 5 Anthracospirifer bifurcatus ..__...... 8.10 sp...... 7 Diaphragmus...... 11 curvUateralis...... 8.11 Caninia...-...... 6 spp...... -.--...-.-. 8 leidyi...... ___...... S, 10,11 excentrica...... 7,11 DibunophyUum...... 10 wetteri...... 8 nevadensis...... 7,11 sp...... 7 araneosum, Faberophyttum...... 6 Zone..._.._.._....._ 5 Dictyoclostus burlingtonensis...... 8,10 Archaediscidae.___.____...... 13, 14,22 Carbonella...... 13 viminalis...... --. 8,10 Archacdiscus...... 16 sp...... 14 Dimegelasma sp. ------8,10 chernoussovensis...... 15,16 carboniferum, Leiorhynchus...... 8,10 diminution, Rhipidometta...... 8,9 krestomikovi...... 15,16 Carnavon Member, Mount Head Formation. 23 Dinant synclinorium ...... 22 arcuata, Rhytiophora...... 8 Casper Formation______.... 20 DiphyphyUum sp---... ------7,10 arculeata, Syringopora...... 7 Castle Reef Dolomite_.____.._._....._ 10 discoidea, Eostaffetta...... 15,16 arkansana, Rhipidometta...... 10 centronatus, Spirifer...... 8,9 Dolomiede Sovet....____. . 22 Asteroarchaediscus...... 23 Charles Formation______...__.. 10 Dorlodotia...... 7,10 baschkiricus...... 15,16 chernoussouvensis, Archaediscus ...... 15,16 dubia, Perdttocardinia.. ----- 8,10 rugosus...... 15,16 Chernyshinetta glomiformis...... 22 duplicate,, Siphonodetta...... 5,6 sp...... 15 tumulosa...... 13,14 E Auloprotonia...... 10 sp...... 14 Chester Series______... 12 Earlandia minima...... 13,14 B Chesterfield Range, coral-brachiopod zones.. 5 sp...... - 14 ChiTrman.tri7.pl interval.______...... 22 Echinoconchusatternatus...... - 6,8,10 baUeyi, Qloboendathyra...... 13,14 Chonetes...... 9 EkmsophyUum...... 6,10 Banes Inferieurs d'Anhee_.__...... 22 sp...... 8 indinatum...... -- 6,7,10 Banff Formation.______...... 22 Cleiathyridina obmaxima...... 8,10 Zone... -..-.---.------.--- 5 banffensis, Eoendothyranopsis...... 15,16 tenuuineata...... 8,9 Endothyra...... -.-. 16 baschkiricus, Asteroarchaediscus...... _... 15,16 Cleistopora placenta...... 7,9 nordvikmtit...... 13,14 bellicosta, Spinoendothyra...... 13,14 cliffordanus, Zaphrentites...... 7 prisca...... ------13,14 bifurcatus, Anthracospirifer...... 8,10 Climacammina...... 16 trachida-...__._...... -- 13,14 Endothyranopsis...... ---- 22 Big Snowy Group...... 11,16, 19,20 15 Composita.. _____..___...... 9 compressa...... -- --- 15,16,22 correlation with other units...... __. 23 sp...... 8 crassa_.. .---._-.--.-- 15,16 biplkoides, Spirifer...... ______..... 8,9 compressa, Endothyranopsis...... 15, 16,22 Eoendothyranopsis banffensis...... 15,16 Bisphaera...... 13,22 Conodonts._.______...__.. 5 ermakiensis...... -...... - 15,16 sp...... 14 cooperensis, Torynifer...... 8,9 macra...... ------15,16 Brachiopods, ranges...... Corals, ranges_____.____._....._.._.. 7 pressa...... --.-...------15,16 Three Forks Formation, Sappington zones, Madison Group_...... 5 rara...... -... ------15,16 Member__...... 9 Cornuspira sp______...... 14 «c«MZa...-. ------15 spiroides...... ------14,16 zones.______.__..__...... 5 Correlation, zone boundaries ______19 Cottonwood Canyon Member, Lodgepole utahensis...... ------15,16 Brachythyris subcardiiformis...... 8,10 Limestone.___...._._...... 9,22 sp...... 14 suborbicularis...... 8,9 Madison Limestone_.-.-....-....._.. 9 Eoforschia...... ------13,16 Bradyina cribrostomata...... 15,16 conodonts_____...... 5 sp. 14 Brazer Dolomite___...... __...__. 10,17 crassa, Endothyranopsis...... 15,16 Eoschubertella...... ------16 Brazer Limestone...... __._...... 16 crenulata, Siphonodetta...... 6,9 sp. -..._-----.------15 brazeriana, Striatifera...... 6,8, 10,11 Cribrospira...... 16 Eosigmottina...... - - 16 brazerianus, Spirifer...... 6',8,11 sp...... 15 sp....".._ .._ . ------15 Bristol, England______...... 22 cribrostomata, Bradyina...... 16,16 Eostaffetta..-.- -. .. - - - - 16 acM.Jss.ma..- -- . ------15 Brunsia...... 13, 14,16 Cribrostomum...... 16 discoidea... ------15,16 Brunsiina sp______...... 14 sp...... 15 sp...... 14 Bull Ridge Member, Madison Limestone.. 16, 19,22 Crurithyris...... 9 Eostaffellidae .------13,23 Burlington Limestone...... 22 sp_...... __--._------.. 8 EotfaffdKna... -.--- . 16.23 burlingtonensis, Cyrtina...... 8,9 cunelformis, Palaeacis...... 7,10 protvae...... ------23 Dictyoclostus___.______...... 8,10 curvilateralis, Anthracospirifer...... 8,11 sp. 15 E27 E28 INDEX Page Page N Page Eotuberitlna sp.....______..._.__._ E14 krestovnikovi, Archaediscus...... E15,16 Neoarchaediscus...... E16.23 ermakiensis, Eoendothyranopsis...... 15,16 Kuechowpora...... 10 gregorii...... 15,16 Etherington Formation.______23 (Kuechowpora) virginica, Syringopora...... 7 incertus...... 15,16 Eumorphoceras Zone_..______.___. 1,23 sp______-. .. 15 ezcavatus, Zaphrentites...... 7,9,10 nevadensis, Caninia...... 7,11 excentrica, Caninia...... 7,11 nordvikensis, Endothyra...... 13,14 laevicosta, Ovatia.... 8,10 expansa, Michelinia...... 7,9 Nudeospira...... 9 laevis, Caldsphaera. 13,14 sp_.-.--...-...... - ----..-.. 8 Latiendothyra...... 13 FaberophyUum...... 6,10 13,14 araneosum...... 6 sp...... 14 lalispiralis, Latiendothyra... 13,14 leathamense...... 6 obmaxima, Cleiothyridina...... 8,10 leathamense, FaberophyUum. occuUum...... 6 6 occuUum, FaberophyUum...... 6 leidyi, Anthracospirtfer...... 10,11 Zone.....______5 oculinum, Lithostrotion (Siphonodendrori)...... 7,10 Leiorhynchus carboniferum.. 8,10 spp...... 7 Old Laketown Canyon 20 Foraminiferal ranges______14 Leptagonia analoga...... 8,9 Omphalotis...... 16 Lipinella...... 16 Foraminiferal zones.______... 1% sp______....----.. 15 comparison with megafossil zones.__ _ 17 sp...... 15 Orbinaria pyxidata...... -. 8,9 Llthostrotion whttneyi...... 6,10 forbesi, Imbrexia...... 8,10 Orthotetes kaskaskiensis...... 8,10 (Siphonodendrori)...... 10 Fossil localities-...... 3 Osage Series...... 12 ociilinum...... 7,10 osagensis, Spirifer...... 8,9 7,10 G Ovatia laevicosta...... ____....-.....--- 8,10 LithostrotioneUa microstylum...... 7,9 gallatinensis, Productus. 8,10 stelcki...... 7,11 Oattendorfia sp...-_.__. 9 Little Flat Canyon.__._...... __.... 20 gigantea, Syringopora... 7 Little Flat Formation-....____.... 10,16, 19,20 Glen Dean Limestone.. 23 pach ysphatrka, Cakisphaera...... 13,14 correlation with other units...... _ n Paine Shale Member, Lodgepole Limestone... 9, OlobivdhmUna...... 16,23 22 Livingstone Formation ...... ----..-..--- 13 17,22 sp...... 15 19,20 Lodgepole Limestone.. .--..-..-.-...... 11, Paint Creek Formation._...... 23 Globoendothyra...... __..... 16,22 conodonts..__------..---...--.-.-..-.- 5 baileyi...... 13,14 Palaeacis...... 7,9 correlatioa with other units__.__..... 20 cuneiformis...... 7,10 gobulus...... 15,16 Cottonwood Canyon Member. -.-.--.. _ 9,22 Palaeonubecularia...... 16 tomiliensis...... 15,16 17,22 Paine Shale Member_.____... 9,13, sp- 15 gobulus, Globoendothyra...... 15,16 Woodhurst Limestone Member. _.... 10, 13,22 Palaeospiroplectammina. 13 glomiformis, Chernyshinella ...... 22 loganensis, Rugosochonetes...... 8,10 tchernyshinensis _.. 14,22 Glomospira...... 16 logani, Retichonetes...... 8,9 Palaeotextularia...... 16 sp...... 14 logani, Spirifer...... 8,10 longiseptata...... 15 Golconda Formation..____._.....---. 23 longiseptata, Palaeotectidaria...... 15 sp...... 14 Great Basin area, Utah, coral-brachiopod Loomis Member, Mount Head Formation.... 22 13 zones..______---._... 5 Louisiana Limestone, age. .-----.-..-..-...-. ParacaligeUa...... Great Blue Limestone______._...... 11 14 gregoni, Neoaichaediscus...... 15,16 paracostifera, Spinoendothyra... 13,14 grimesi, Spirifer...... 8,10 M parakrainka, Septabrunsiina ... 13,14 Grove Church Formation...... 17 Parathurammina sp...... 14 macro, Eoendothyranopsis...... 15,16 Pekisko Formation _ ...... 22 H Madison cycle...... 5 Perditocardinia dubia ...... 8,10 Madison Group...... __...... 12,20 Pericyclus (Caenocyclus) sp-... 9 HapIophragmeUa...... 13 coral zones...... 5 sp...... 14 (Rotopericyclus) sp...... 9 Madison Limestone...... 10,11,13,17,19 Permia...... 7,9 Harrodsburg Limestone...... _...... 22 Bull Ridge Member...... 16,19,22 Hayasakaia...... 11 Pitkin Limestone _ .. ..-. 17 Cottonwood Canyon Member.-.--.-__ 9 placenta, Cleistopora...... 7,9 conodonts.--..-.------. 5 Hedraites..... Planospirodiscus...... 16,23 madisonensis, Spirifer...... 8,10 sp...... 15 sp...... Manning Canyon Shale...... 11 Helicospirina. Plectogyra ...... 13 Marbre noir de Dinant...... 22 pressa, Eoendothranopsis ...... 15,16 sp. Marston Member, Mount Head Formation. 22 Hemiarchaediscus- ...... 16 primaeva, Septaglomospiranetta. 13,14 Megafaunal zonation, historical development- 6 prisca, Endothyra...... 13,14 sp...... 15 Megafaunal zones..____.._....__ B henbesti, Septatournayella...... 14 Productus gaUatinensis...... 8,10 comparison with foraminiferal zones_... 17 Propermodiscus...... 16 Hiatus, post-Madison.-.._...... _. 20 correlation with the type Mississippian 12 hirsutiformis, Quadratia...... 6,8,10 Protva Formation- - --- 23 Meramec Series..___ .... . 12 protvae, EostaffeUina...... 23 Homalophyllites...... 6,9,10 metoMica, Camarotoechia...... 8 spp...... 7 Pseudodorlodotia...... 7,10 Homoceras Zone...... 1 MetriophyUum deminutivum...... 7,9 Pseudoendothyra kemenskensis.. 15,16 Michelinia expansa...... 7,9 Pseudoendothyridae...... 23 Microfaunal zones.....----.--...---.--....--- IS Pseudopolygnathus dentilineata. 5 Imbrexia forbesi...... 8,10 microstylum, Lithostrotionetta...... 7,9 Pseudostaffetta...... 16 incertus, Neoarchaediscus...... _ __... 15,16 Miderena...... 16 15 inclinatum, Ekvasophyttum...... 6,7,10 sp...__ ...... -. 15 Punctospirifer solidirostris. 8,10 Irregularina sp...... 14 minima, Earlandia...... 13,14 pyxidata, Orbinaria...... 8,9 Mission Canyon Limestone.____.___ 10,13,19 correlation with other units___.__... #2 Q, kaskaskiensis, Orthotetes...... 8,10 Mississippian System, correlation with Euro kemenskensts, Pseudoendothyra...... 15,16 pean terminology__...._ 1 Quadratia hirsutiformis...... 6,8,10 keokuk, Spirifer...... 8,10 Monroe Canyon Limestone______. 10,11,16,19 Keokuk Limestone...----.--.-----.-----._. 22 Radiosphaera...... 13 Kibbey Sandstone--..--._...... ___ 20 correlation with other units_____ -.-.. 82 Kinderhook Series...------__.__-. 12,19,22 Mount Head Formation, Carnavon Member.. 23 sp...... 14 Kinkaid Formation..--______...... _ 23 Loomis Member...... ------22 rara, Eoendothyranopsis...... 15,16 Koninckopora...... 16,22 Marston Member..-..-...... -- 22 RectoseptaglomospiraneUa...... 13 sp...... 14 Salter Member ------.-..------.-- 16,22 sp____.. . 14 INDEX E29 Page Page Red wall Limestone, foraminifers. ______E12 Spin oendothyra ...... E13 Timania...... E6 Retichonetes logani...... 8,9 betticosta...... 13,14 tomUiensis, Globoendothyra...... 15,16 Rhipidomella arkansana...... 10 paracostifera...... 13,14 Torynifer cooperensis...... 8,9 diminutiva...... 8,9 spinosa...... 13,14 Tournayella...... _...... 13,16 Rhopalolasma...... 6,10 sp...... 14 sp...... 14 sp____.______....__.___ 7 spinosa, Spinoendothyra. 13,14 trachida, Endothyra...... 13,14 Rhytiophora...... 9 spinulosus, Zaphrentites. , 10,11 Trepeilopsis...... _....._. 16 arcuata...... 8 Spirifer...... Sp.-... . __. ______._. 15 (Rotopericyclus) sp., Pericyclus.,...... 9 biplicoides...... Triplophyttites...... 6 rowleyi, Spirifer...... 8,10 brazerianus...... tuberculata, Tuberendothyra...... 13, 14,19 Rugosochonetesloganensis...... 8,10 centrmatus ...... Tuberitina ...... 13 rugosus, Asteroarchaediscus...... 15,16 grimesi...... 8,10 sp...... 14 Rylstoniateres...... 7,9 keokuk...... 8,10 Tuberendothyra...... 13 logani...... 8,10 tuberculata...... 13, 14,19 S madisonensis ...... 8,10 sp-...... 14 tumulosa, Chernyshinetta...... 13,14 Ste. GenevieveLimestone...... _...... 22 rowleyi...... 8,10 Turner Valley Formation.....-...... ,.-. 22 Salem Limestone______. ___ 20,22 honensis...... 8,10 typicum, Ankhelasma...... 7 Salter Member, Mount Head Formation... _. 16,22 sp. sandbergi, Siphonodella --..-...... 5,6 s, Eoendothyranopsis...... 14,16 U Sappington Member, Three Forks Formation, Stacheia...... 14,16 Unispirifer. brachiopods______...... 9 Stacheoides...... ,...... 16 Schuchertella...... 9 sp_._____-...--.---- .... 14 utahensis, Eoendothyranopsis...... 15,16 sp. stelcki, Lithostrotionella...... 7,11 scitula, Eoendothyranopsis...... 15 Stratigraphic sections, location.._...... _- 2 Sedimentation cycles, Mississippian...... 5 Striatifera brazeriana...... 6,8,10,11 Septabrunsiina...... ___... 13 subcardiiformis, Brachythyris...... 8,10 Vesiculophyttutm...... 6,9,10 parakrainica...... _.....__...... 13,14 suborbicularis, Brachythyris...... 8,9 sp.__....______..__.___..... 7 sp...... _...... 14 sulcata, Siphonodella...... 6,9 Virtuesphaera sp...... 13,14 SeptaglomosplraneUa...... 13 Sun River Member, Castle Reef Dolomite 10 viminalis, Dictyodostus...... 8,10 dainae...... 13,14 Syringopora...... 9,10 virginica, Syringopora...... 10 primaeva...... 13,14 aculeata...... 7 Syringopora (Kuechowpora)...... 7 sp...... 14 gigantea...... 7 Septatournayetta. --...... 13 virginica...... -.... ------10 W henbesti...... 14 (Kuechowpora) virginica...... 7 SyringoporeUa...... 10,11 Warsaw Limestone ...-___.____.__ 22 sp. - ... 14 sp...... -...... ------. 7 wetteri,Anthracospirifer...... 8 shoshonensis, Spirifer...... 8,10 Syringothyris...... - 9 White Knob Limestone----.----.----...... 10,11 Shunda Formation____._____._... 22 sp...... 8 whitneyi, Lithostrotion...... 6,10 Siphonodella crenulata...... _...... 5,6,9 Ltthostration (Siphonodendron)...... 7,10 duplicata...... 5,6 T Willistonbasin...... - ..- .-. 12 ...... 5,6 tantilla, Cyathaxonia...... 7,9 Woodhurst Limestone Member, Lodgepole ...... 5,6,9 tchernyshinensis, Palaeospiroplectammina...... 14,22 Limestone______._____ 10,13,22 crenulata Zone.....___.___._..... 5 tenuilineata, Cleiothyridina...... 8,9 sandbergi-S. duplicata Zone.__._..... 5 teres, Rylstonia...... 7,9 Tetrataxidae..... -. ------13 ZaphrentUes...... 7,9,10,11 sulcata Zone______._.._ 5 Tetrataxinae. _.. ____._ _.-..------. 22 (Siphonodendrori), Lithostrotion...... 10 Tetrataxis...... 13 cliffordanus.-...... 7 oculinum, Lithostrotion...... 7,10 Sp . - 14 excasatus-..-.-...... 7,9,10 whitneyi, Lithostrotion...... 7,10 Three Forks Formation, Sappington Member, spinulosus...... 7,10,11 solidirostris, Punctospirifer...... 8,10 brachiopods...... __ 9 Zone boundaries, correlation...... _...... 19 o