111 cc tr.: • THIS MATERIAL MAY BE PROTECT) BY COPYRIGHT LAW j":

DEPARTMENT OF THE INTERIOR FRANKLIN K. LANE, Secretary

UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, Director

Professional Paper 98

SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION

BY

FREDERICK LESLIE RANSOME

Publbilied July 17, 1916

Shorter contributions to general geology, 1916

(Pagea1311-166)

WASHINGTON GOVERNMENT PRINTING OFFICE 1916 CONTENTS.

Page. Purpose and scope of paper ...... 133 Topographic provinces of Arizona ...... 133 Ray-Globe geologic section ...... 135 General featuree ...... 135 Piaui schist 135 Scanlan conglomerate ...... 136 Pioneer shale ...... 13(1 Barnes conglomerate ...... 137 Dripping Spring quartzite 137 Mescal limeetone ...... 138 Troy quartzite 139 Martin Limon one 141 Tornado limestone 142 Nomenclature ...... 143 Santa Catalina geologic eection ...... 144 Bisbee geologic eection ...... 145 Tombstone geologic election ...... 148 Clifton geologic section 149 Rooaevelt geologic section ...... 149 Canyon Creek geologic section ...... 152 Sierra Ancha anti Matatztel Range ...... 153 Carr's ranch and vicinity ...... 153 Greenback Valley and vicinity ...... 154 Bellamy Basin 155 Pro- sediments of the northern Sierra Anella and of the Mazatzal Range...... 157 Jerome geologic section, with notes On stratigruphy between Payson and Jerome ...... 159 Grand Canyon geologic sections 162 Correlation ...... 164 111 ILLUSTRATIONS.

Page. PLATE XXIV. Map of Arizona ...... 134 XXV. Generalized columnar sections of the Paleozoic strata of Arizona from Mexico to the Grand Canyon ...... 136 XXVI. A, Barnes conglomerate at south end of Pinal Range, Globe quadrangle, Ariz.; /I, Mescal limestone on El Capitan Creek, Mescal Range, Ray quadrangle, Ariz., showing effect of weathering; C, Barnes conglomerate, El Capilan Creek ...... 138 XXVII. Quartzites of the Ray quadrangle, Ariz.: A, Cross-bedded pebbly Troy quartzite, Dripping Spring Range; B, Banded Dripping Spring quartzite, Mescal Range, 1 mile south of Pioneer ...... 139 XXVIII. Mescal limestone In the Ray quadrangle, Ariz.: A, Typical exposure of the chert y Mescal limestone in the Dripping Spring Range, 2 miles south of Dripping Spring ranch; B, steeply upturned Mescal limestone with intrusive diabase in the Tortilla Range, about 0 miles south of Kelvin ...... 140 XXIX. Sections of Paleozoic rocks in the Ray quadrangle, Ariz.: A, Section on El Caption Creek, MeHeal Range; B, El Capitan from the northwest 141 XXX. Abrigo limestone in the Mule Mountains, Ariz.: A, Typical exposure three-fourths of a mile northwest of Military Hill, Tombstone district ; B, Typical exposure on Escabrona Ridge, west of Bisbee ...... 144 XXXI. Outline map of the Tonto region, Ariz ...... 148 FIGURE 11. Section through gorge near Roosevelt, Ariz., looking northwest ...... 150 12. Diagrammatic section across the Sierra Ancha, Ariz., near Aztec Peak ...... 153 13. Diagrammatic section on the North Fork of Deer Creek, Ittazatzal Range, Arir ...... 158 !4. Diagrammatic section across Pine Creek at Natural Bridge, Mir ...... 159 Iv SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION.

By FREDERICK LESLIE RANSOME.

puRpOsE AND SCOPE OF PAPER. of other strait igraphic 'sec tions to the southeast During the last 16 years detailed geologic and northwest, and (3) a discussion of the corre- work has been done in a number of mining dis- lation of these sections from the Grand 6anyon, tricts in Arizona, several reconnaissance reports in the northwestern part of the State, to Bisbee, have added to our knowledge of the geology of near the Mexican border. the State, and sections of Paleozoic and older The positions of the sections discussed may rocks in the Grand Canyon and at Globe, Ray, be seen by reference to the outline map (Pl. Clifton, Tombstone, and Bisbee have been XX IV) and to the diagram accompanying the carefully studied; but hitherto the investiga- correlation chart (Pl. XXV, p. 136). tions in most of these fields have been uncon- TOPOGRAPHIC PROVINCES OF ARIZONA. nected by reconnaissance examinations of intervening areas. Realization of this lack of The State of Arizona may conveniently be divided into throe topOgraphic regions—the correlation• led, in 1912, to a preliminary reconnausance of the country extending north- plateau region, the mountain region, and the wostward from Globe to Jerome, in the hope desert or bolson region. The plateau region, that light might thereby be thrown on the which has an area of about 45,000 square nature of the changes that connect the well- miles, occupies the northeastern part of the known stratigraphic section of the Grand Can- State and drains generally northward through the Little Colorado and smaller streams yon With the very different succession of beds into at Globe. A visit to the Santa Catalina Range, the Grand Canyon. The general altitude of this region, which is a portion of the northeast of Tucson, in company with Prof. great C. F. Tolman, jr., who is preparing the Tucson Colorado Plateau, ranges from 7,000 to over folio for the United States Geological Survey, 8,500 feet. As Dutton graphically describes it, afforded an opportunity of partly closing the Its strata are very nearly horizontal, and with the excep- tion of Cataract Canyon and some of its tributaries it is gap of terra incognita between Ray and Tomb- not devply scored. Low mesas, gently rolling and usually stone. Detailed work on the Ray quadrangle, clad with an ample growth of pine, pidon, and cedar; the full results of which are not yet published, broad and shallow valleys, yellow with sand or gray with has supplied the materials for a much more sage, repeat themselves over the entire area. accurate description of the geologic column in Hero and there the Kailmb (Pennsylvanian) central Arizona than was heretofore possible, limestone, the prevalent surface rock, is covered and similar work in the Tombstone district by flows of basalt or bears erosion remnants of has extended the Bisbee section northward. younger strata, and above it, north of Flagstaff, Finally, some additional reconnaissance has rise the lofty extinct volcanoes of the San Fran- been made of the Mazatzal Range and the cisco Mountains. Sierra Ancha. The southwestern limit of the plateau trav- The present paper includes (1) a brief intro- erses the State in a general southeasterly direc- ductory outline of the broad topographic fea- tion from the Grand Wash Cliffs, near the tures of the State, (2) a description of the full eastern border of Nevada, to the New Mexico and very satisfactorily exposed geologic sec- line, a few miles northeast of Clifton.* This tion of the Ray-Globe region, with less detailed Dutton, C. E., Tertiary history of the Grand Canyon district: U. 8. accounts, in part abstracted from the literature, Oeoi. Survey Mon. 2, p. 14, 1882. 133

•

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MAP OF ARIZONA. ' 184 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1910.

boundary along much of its course is a single ered the edges of the nearly horizontal sedi- bold cliff 2,000 feet or more in height, but else- mentary rocks; but these beds appear again where it is less definite or simple, owing to a at the head of Fossil Creek and continue east- distribution of the total difference in relief ward past Payson in the great southward- among a series of great topographic steps or to facing cliff that marks the descent of about local accumulations of volcanic rocks, espe- 2,000 feet from the Mogollon Mesa to the cially basalt. In general the outer or lower Tonto Basin. From Fort Apache eastward to line of cliffs separates nearly horizontal find the New Mexico line the plateau boundary undisturbed strata on the northeast from becomes less distinct. Erosion has partly de- faulted and tilted beds on the southwest, and stroyed its continuity, and vast accumulations locally, as along the Grand Wash Cliffs, this of volcanic rock have obscured the original line is itself a fault scarp, more or less modified plateau surface. by erosion. The second topographic division, the moun- The Grand Wash Cliffs rise precipitously tain region, which adjoins the plateau region 3,000 feet or more above the plains to the west. on the southwest., is essentially a broad zone According to Lee,' pre-Cambrian granite is ex- of short nearly parallel ranges, among which are posed at their base and the Redwall limestone the Dragoon, Chiricahua, Whetstone, Pinaleno,

forms their crest and the floor of the adjacent Galiuro, Santa Catalina, Pinal, Superstition) plateau. About 45 miles east of the Musio Ancha, and Mazatzal, extending diagonally Mountains a second gigantic step, that of the across the State from the southeast corner to Aubrey Cliffs, north of Seligman,' carries the Colorado River. The width of this zone may geologic section nearly to the top of the Kaibab be taken as from 70 to 150 miles, but its south. (Pennsylvanian) limestone, which forms the west boundary is not susceptible of precise de- surface of the Coconino Plateau, south of the marcation. Few of the individual ranges ex. Grand Canyon. South of the Music Moun- ceed 50 miles in length or 8,000 feet in altitude. tains there is another ample terrace in the Their general trend is almost northwest, but ascent from the valleys of the mountain region near the Mexican border it becomes more nearly to tho Colorado Plateau—that of the Trux ton north, and the mountain zone as a whole 004.• Plateau. This bench, which lies between the tones with a belt. of north and south ranges that Cottonwood and Aquarius cliffs to the west extends through New Mexico and borders the and the Yampai Cliffs and Juniper Mountains plateau region on the east. to the northeast, is described by Lees as a Most of these ranges consist mainly of quartz- granitic peneplain partly covered with volcanic ites and limestones of Paleozoic or earlier age, rocks. resting with conspicuous unconformity upon South of Ash Fork the continuity of the granitic, gneissic, and schistose rocks. All plateau escarpment is interrupted by flows of these rocks are out by later intrusives, espe- basalt that poured down from the plateau to cially by diabasio and monzonitic rocks, and the valley of the Verde, forming 'a slope that arc partly covered by flows of lava. Struc- has been utilized by the Santa Fe, Prescott & turally these ranges are characterized by the Phoenix Railway between Ash Fork and dominant part played by faulting as compared Jerome Junction. East of this railway and with folding. The great copper deposits of north of Jerome the edge of the plateau is in Arizona, so far as they are known, are all, ex- general a scarp (part of the Aubrey Cliff of cept that at Ajo, within this mountainous Gilbert 4) over 2,000 feet in total height, with zone. deep reentrants and bold pinnacled promon- Adjoining the mountain region on the south- tories. East of Camp Verde a thick series of west is the third topographic division, the desert basaltic flows with associated tuffs has coy- region, which also contains numerous short

1 Lee, W. T., Geologic reconnaissance of a part of western Arizona: mountain ranges of prevalent northwesterly V. S. Geol. Survey Bull. 352, P. 19, pl. 1, 190$. trend. In this region, however, most of the 'See Barton, N. IL, A reconnaissance of parts ot northwestern New Mexico and northern Arizona: 17. S. Geol. Survey Bull. 435, p. 8, pl. 1, ranges are separated by broad desert plains 1910. underlain by fluviatile and lacustrine deposits Op. cit., p. 21. 4 U.S. Geol. Surveys W. 100th Mer. Rept., vol. 3, p. 49,1871. of late geologic age, or by undulating granitic SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 135 lowlands partly covered with gravels and flows of the Globe quadrangle, the geographic term of lava.' The boundary between the moun- of the designation being derived from the Pinal tain and desert regions is, as previously stated, Mountains, on whose slopes the schists are indefinite but may provisionally be• taken as a extensively exposed. As was then pointed curved line extending from Nogales, on the out, these rocks probably correspond to what Mexican frontier, past Tucson and Phoenix to Blake ' 20 years earlier had called, the `` Ari- Needles, near the California line. The main zooian slates," but as the geographiC term of drainage lines of both regions are transverse to his name did not accord with the principles of the trend of the ranges, the run-off finding its nomenclature followed by the Geological Sur- way through Gila and Williams rivers into the vey and as his lithologic term was not appro- Colorado. The minor streams, many of them priate for crystalline schists, that designation intermittent, occupy in general the valleys be- could not well be retained. Since the publica- tween the parallel ranges. tion of the Globe report the name Final schist has been applied to the pre-Cambrian crystal- RAY-GLOBE GEOLOGIC SECTION. line schists of the Clifton-Morenci' and Bisbee' GENERAL YEATURICs. districts. This formation has of late years at- The Ray and Globe quadrangles, as may be tained economic importance as the principal seen from the diagram on Plate XXV, are in country rock of the disseminated copper de-. south-central Arizona, and the Ray quadrangle posits at Ray and Miami. lies immediately south of the Globe quadrangle. Most of the Final schist is light gray to They include the Final Range and parts of the blue-gray in color and has a more or less satiny smaller Mescal, Dripping Spring, and Tortilla luster on the cleavage surface. In texture it ranges. The relative positions of these ranges ranges from cryptocrystalline slaty sericitio are shown in the outline map of Plate XXIV. schist through fine-granular fissile rocks to im- The rocks are intricately faulted, the fault perfectly cleavable, coarsely crystalline quartz- pattern being on an extraordinarily minute muscovite schist carrying andalusite or sill- scale, and the stratified rocks have been exten- manite. The coarsely crystalline varieties oc- sively invaded by diabase. Nevertheless, ex- cur chiefly in the vicinity of granitic intrusive cellent sections, of the kind illustrated in Plate masses and grade into the less intensely meta- XXIX (p. 141), may be studied in the Mescal morphosed varieties that make up the bulk of Range and in many of the larger fault blocks the formation and are characteristic of most of the Dripping Spring Range. The total of the exposures in the Ray quadrangle. thickness of the beds below the base of the Car- In the vicinity of Ray and west of that town boniferous limestone and above the pre- a considerable part of the schist is a gray fine- Cambrian crystalline rocks is about 1,000 feet. grained, moderately fissile rock that has the The limestone is at least 1,000 unmistakable aspect of a squeezed and meta- feet thick and is limited above by a Mesozoic morphosed sandstone. Thin sections of this erosion surface. No evidence of angular un- variety, seen under the microscope, show conformity has been detected within the Paleo- rotund but irregular grains of quartz as much zoic sedimentary series in the Ray quadrangle, as 5 millimeters in diameter in a groundmass although the exposures are so good that any consisting chiefly of quartz and sericite. The appreciable angular discordance could scarcely large quartz grains show the effects of granula- escape recognition. tion with more or loss recrystallization under FINAL SCHIST. pressure. The Final schist and intrusive batholithic Associated with those schists that are clearly masses of granite and quartz-mica diorite are of sedimentary origin are very subordinate the fundamental rocks of the Ray-Globe region. masses of greenstone schist and other varieties The name Final schist was first applied in that were originally igneous material. 3 1903 to the pre-Cambrian schistose terrane Make, W. P., Geology of the Silver King mine: Eng. and Min. Jour., vol. 35, pp. 238-209, 1883. AntlasU, Thomas, U. FL Pacific R. H. ExpL, vol. 7, pt. 2, pp. 130-138, 2 Lindgren, Waldemar, The copper deposits of the ClUton-Morenci 1857. district, Arlt.: U. S. Geol. Survey Prof. Paper 43, p. 56, 1905. t Ransoms, F. L., Geology and ore deposits of the Globe copper dis- a Ransome, F. L., The geology and ore deposits of the Bisbee quad- trict, Arts.: U. S. Geol. Survey Prof. Paper 12, p. 23, 1903. rangle, Ariz.; U. S. Geol. Survey Prof. Paper 21, p. 24, 1904. PROFESSIONAL PAPER 98 PLATE SEA

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CAMP ...."•syrn c.scoCI I APACHE INA 2 mONAVE CHINO S •I P. Senates A , „,", :„T , I Is. ;N A V .1 c 040 ef TAbSAVAN X !”... . ,.. - . -- Nf ,. ---skis .lt \ , \ --,--,- -- - -R - / GRANDKAIBAB DIVISIONCANYON -1-' I.-- "'I' , Holbrook ' I work - ' A V 5_,1_,,iimitst , r/ Based Chiefly on -.3-.5‘'. I III.P IAm'I I of L_F. Noble, ' - RE I- . , ' '. VEEN. ''''''''''''' it John:, _ - U.S. Geological Survey I */ _ 0 A I Bulletin N .S . I I ii. 549. Plate IX, % cfP ' Am. )----- 1914 . ____ , ,Pkrker --,1._'' . r ' 0,,,,,em-iiile i ,..," '*,.., A , • _.„ \,.p. -., ,, ,7 r ... . . , ,i- ‘..-----' -I Sey or/ I ill 'VI do-...,I II..;. ,. . '? Erosion surface Y 1 U M A I _,,_, , Kai bab limestone • , - - IK,.... -.Tir ' 400 600feet Upper portion,dense gray crystal- / line limestone, cherty near top. CemR A H IM Fossiliferous. - —Li _ , Fori'erwat Lower portion, buff limestone I o ------and calcareous sandstone I I" 1 to A TII-5,,,m I I:** 2 .. . ! ' It T mbetone Xi I .-,il-wwwvisrEs.wow-spro...... kp h, Coconino sandstone -n li wber / 1,1 8 250-350 feet / -k- .- • Light-buff fine-grained cal- GULP OP Careous Con- CALIFON:MI 11 spicuoussandstone cross-beading with -s-- u 01 o 75 50 75 no Miles

INDEX MAP SHOWING LOCATION OF SECTIONS MEASURED AND RELATION OF LOCALITIES VI SITED TO PUBLISHED TOPOGRAPHIC AND 1 GEOLOGIC WORK IN ARIZONA Outlined rectangles represent topo raphic maps_ Shaded areas represent published eolo ic folios Dots and roman numeralsg represent locations of columnar sections g g IX

REGION 1 Supai -formation VI --_-;._ —--JEROME ' 1,250 I,400feet Ransome F.L. - From unpublished UP:snrdsptOrie'Tdo:clreshat'. * —..- SOUTHEEkN PART -,.... --- ' data Lowerrained portion,cross-bedded hard sand-fine- SIERRA ANCHA 5 gstone. interbedded with is ,1 ' red shale RansomAEL , VIII : From unpublished , - - - / data s ! ,,,- HEAD OF Fecs!on surface --- .,' ,, - CANYON CREEK Oil berEG.K. / s,' Wheeler Coconino sandstone Survey,- 500= feet Summit of ActecPeak / . 3, pp 163 164, 3 Vol. /;4 ' 1675 flne- rained thick-bedded Massio , ediurn- ra ed uarl2itic Sparkling buff to white sand- LTi n..Aol7 q ill stone withg consornuouS cross- VII Leading rd with white streaks ouarttitio ofpebbies- sandstone ke;;;Mr.i NORTHERN PART geds5-6 feet. Formscliff. OF tell , _54) ZOO feet Redwa II limestone Coarse pebbl i obuffsandstone. SIERRA ANCHA 600 -700 feet g4g DELSHAY BASIN Coconino sandstone Al ternating beds of calcareous ma:Zri.tf'07,t0=47.YA* RanSOrne,F.L. 525 feet sandstone,thin-bedded mottled 4.T" FrOFrom unpublished limestone, and dense blue- ray Massive fine-rained pinkto buff data Massive cross-oeddedsandstone yellow limestone in lower porton; gpass- sandstone_g Forms cliff. Sups i formation ? ing upwatt into dense blue-gray 1,000sfeet limestone withbetktin ptanes Layois000ffMables indistinct g Soft calcareousshales andsand• Crest of Sierra Ancha stonesGeneral wan cp,orsome sbri andht li red.mestone,mestone. Fine-grained homogeneous pinkish and Compact ray limestone.65feet g at top stone. sandstone. Weathers slaboy and Purplisn-brown calcareous shale135eeet g Thick bed of gray ,imestone forms slope. Impure &lefty limestone. TernjfiregteRI imest0.01. feet rapOsures 300 lackin . Fra ents of 0-100 feet- nd'ea'r,l.gaTIPZ:cng gm "'"`' so ovoomoemtre Fine -nrmlnizg6b4o.otrn flaggy Ui Thin-bedded Red andpurple sandstone, Muav limestone I's,ZIrVesicularI basalt flow. 50Sfeet Thin-bedded flaggy sandstone soft at top, massive below. 450-475feet wt. some shale Weathers rusty 500 feet Impure thin-bedded Monti- Mescal limestone 51,,e., 100 th ELn (thiekneSS gney limestonee Z unknown) Massive snnk feet 9 wi chafactess Forms ovarcitie75feet sandstone. < No ood .posures seen. istie mottling due to lenses g nk quartalticcliff. sandstone. of shaly material Probably about 250 feet . siope. 25feet. Redwall limestone ? 03 Masso Forms . . ., s,ndstone. 250 feet ugt g416140a Redwal I I i rnestone ? Think-bedded white and gray trite Conglomerate 2 feet 325 feet limestone rown Dripping4r4neltquartzite fine- rained red-bro Alternatin ray limestone and Massive g shale w,thg g some sandstone. Bright Angel shale sandstone. Beds12 feet or more - thick.Cross-beddee at low angles. FossiliFerous 25 375feet Same general character as in Forms cliff. ; sh reenish micaceosu sandyndy Ray uadran les ISO feet UNCONFOFOWTY ? A g Globe andat q g shale with two thin beds of and Roosevelt Brown to red wary< v.t.eous o e- brown limestone locally stoneonssive sho.y. T ApparentJyfineigrained red - Land to in middle_ on upperpart. brown sandstone Exposures poor sanestm.cztbering coming sandy Fossiliferous Grey red fossil . Barne_gatomerate Coarse red -brown arkosic Stalk cal.reg4:rdsione. 500 feet Tapeats sandstone 0-285feet ses-. Pione2eorof4;ation ofguartutic con ionerate sandstone, and ofwith spotted layers g shale.1500eet Vtreosuas,,red.p,u,715ed afrs.clt white slabby cross-bedded oelok Red-brown eandatOnSwith red Brown Some arkosic maroon shale sandstone with lenses or fast .6 Rusty cross-bedded pebbly conglomerate in basal portion Con lomerate. 3feet 25 Be feet g sandstone UNCONFORMI7Y - - GRr‘l Tc°(.72CI7FORW177-v't GREAT UNCONFORM/TY GREAT 451CMFORM/rY GREAT OA/CONFORM/TY GREAT Grand Granite ° Canyon senes.YornEer ere- Horn medies anb,lezdhestr;o.ek Cambrian.incluoingerase,mn over4.,30 estone,suaie, tee Granite Ilimabo.,: nconfor,ably • section ortlerelsekhere Schist of convom and younger Cambrian quan,te.ano sandsto e, resting schist ono conglomerate)pre-Cambrian n quartzite

./EOLC.11.di COL SURVEY

BISBEE ,.ansome,F.L. ,- :3 3eologi al Survey kr ..i 1nssional Paper 21, 1904 Sb

Glance conglomerate and Overlying \ , fOrmations,all of Comanche age GENERALIZED COLUMNAR SECTIONS UNCONFORMITY OF THE

TOMBSTONE _ PALEOZOIC STRATA OF ARIZONA liansOme,F.L. From unpublished FROM MEXICO TO ME GRAND CANYON data `N. N. Compiled by ELRANSOME \ 1916 BedS as yet unnamed. whose \ position within the Mesozoic col- tonn is uncertain VERTICAL SCALE - Ty- 500 0 500 1,000 FEET UNCONFORMITY 1.-■■1

MIN

Waco limestone 3,000feet 1 1 Plus unknown thickness re- 11—• moved by erosion. Chiefly light-gray, white, and pinkish beds of moderate thickness. Abundant fossils

0 Naco limestone (Thickness not measured. Probably about the same as at Bisbee) Same general character asat \I Bisbee GLOBE AND RAY QUADRANGLES

r a 'e EL -...... _ /AashingtlriTcademy Cif Sciences ‘,. - Journal 't vol. 5, pp. 380-388 5 28; 1915

'22

\ 1.5 VI Andesite,andesite breccia,and \ „ UNCONFORMITY - SOUTHERN PAI - OF THE SIERRA ANC1L Hansome,F.L From unpublished Tornado limestone data 1,000 *feet Thick beds of light-gray limestone. ROOSEVELT Ransome,F.L. at Fossils scarce in lower or Mississip- pian portion buk plentiful in Penn- From unpublished sylvanian portion. data Summit ofP IIMI No recognizable plane ofdivision between Mississippian and EMI Pennsylvanian Escabrosa limestone at 700 feet CLIFTON After Lindgren,W. Thick-bedded, white and light- U.S.Geological Survey gray limestone. ESCabrosa limestone folio 129, Fossil iferous 1905 500 feet I Tornado limestone • M (approximate only) 1-1 Thick bedded white and I ight- /.. gray limestone. IMM Fossiliferous Martin limestone NMI Martin limestone Pinkard formation 325 feet MOM EMI Generally rather thin beds. r="7. 300± feet Shale and sandstone of Benton Fossiliferous in upper hatf. rara Thin dolomitic beds with some Martin limestone aga Gritty at base. Shale at top sandstorm and shale, especially 340 feet L/NCONFORINITY in upper part Dark-gray limestone'', moderately Um. Martin limestone r—- 0 thick beds with some shale. maw 340 feet Troy sandstone Fossiliferous fossiiiferous 60 feet in upper half Dark-gray limestone Troy quartzite with some soft shale ross bedded pebbiy sandstone. EMI 50 Tule Spring_ limestone 400feet Some shaIe nearbase wir 500feet Generally pebbly cross-bedded quanta vesicular basalt flow. 50 feet (Includes some Mississippian) ite Emmet at with lenses of conglomerate. GRVII IdeeSe .• Thick-bedded blue-gray li mestone Shaly rusty beds with worm casts 1 at top 2 Mescal limestone 7.301.0 :EM- 300 feet SSERMISI 0 TRAN Abrigo limestone at Ulm Hard, rather thin bedded chertv 770 feet at =In dolomitic li mestone. ' - Abrigo limestone Modoc limestone Vesicular basalt flow. 25 75feet Weathers dark Thin-bedded impure, in part 700 feet Ca 180 feet shaly, in part arenaceous,very Upper 100feet pure thick-bedded Mescal limestone cherty dolomitic li mestone. Thin-bedded impure cherty li mestone; lower 80feet dolomitic limestone with shaly oartwith 225 feet Carries Middle Cambrian fossils. and in one bed of sandstone Thin varicolored, more or less Bed ofwhite quartzite about COGS. sandy layers. dolomitic beds with conspicuous 8 Morenci formation feet thick at top eedoe=e• Bed of white quartzite about cherty layers OCRS 5 feet thick at nap 150 feet Black clay shale grading down in Dripping q''ftzite to ar Wanes, hmestone 5EV;4t Dripping Xign.gtquartzite 1 MAGI - S' - ••■•M LO nRI,slc:or i:0Foof r;Vion Ec%rL74 2,2;:.-174A.'" StBinoss arkosic MOOS RAS.9 Fine-grained voricolOred 176.1.1 Cherty loo311, darlered ISSINSIS ar:Ei M1.21211 limestone. dolomitic. quartzite, much of it with manits La wer .250 feet thinner-bedded, and gray banding Partings between siossim nnth cons■Oerable shale. beds na distinct. Ripple marks Ordovniad fossils in upper Boise quartzite division BarnT_SpaOtrnerate Boise quartzite at 430 feet. 440feet Pioneer shale Cross-bedded and pebbly. In Hard upto green moderately thick beds layerof quartzite in beds rn'ToWZ-7't` 255 feet thick.Sma II scattered pebbles Coronado arbor, shale grading into massive conglomerate at base quartzite art,,,c 11111015SEI 200 feet Pionee strain, 150 feet hard sandstone below Brown and red quertzitie sandstone Maroon shale,arkesic and quartitic near 171.39E Ponflomerate.30 feet Thin conglomerate at base with conglomerate locally at base ; . RSAPP. Men conglomerate. 0-15 feet Pebbles , th inch, GREAT UNCONFORMITY GREAT OA/CONFORM/TY GREAT UNCONFORMITY GREAT UNCONFORMITY GREAT un CONFORMITY Pinal schist b'ericitic schist; bhiefly meta- Pinal schist Final schist Final schist and granite Granite norphosed sediments. Cut by and gneissic quartt-inica diorite nit intrusive granitic rocks granite 186 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1918.

SCANLAN CONGLOMERATE. PIONEER SRAM At the base of the sedimentary column at Ray In the Globe report the name Pioneer shale (see P1. XXV) is the Scanlan conglomeiate, was given to a series of shaly beds that overlie first described in the Globe report, where it the Scanlan conglomerate and underlie the was said to be from 1 to 6 feet thick and com- Barnes conglomerate. The typical seetion is posed of imperfectly rounded pebbles of vein that exposed on the northeast slope of Pioneer quartz with scattered flakes of schist held in a Mountain. pink arkosic matrix. The Scanlan conglom- In most places the Pioneer formation consists erate is locally the most variable of all the of dark reddish-brown, more or less arenaceous Paleozoic formations, both in constitution and shales composed largely of fine arkosic detritus in thickness. It was evidently formed, with with little or no calcareous material. In somt little transportation, from the materials that beds fragments of pink feldspar are easily the waves of an advancing sea found lying on a recognizable with the unaided eye, and as a well-worn ancient surface of low relief. Areas rule the shales toward their base grade into of schist, were littered with fragments of white arkosic grits. These arkosic basal beds are vein quartz, and .the upper parts of granitic well developed in the Apache Mountains, just masses were deeply disintegrated. Consequently northeast of the Globe quadrangle, where they the basal conglomerate where it rests on the attain a thickness of approximately 175 feet. Pinal schist is composed chiefly of imperfectly Up to a horizon 75 feet above the granite the rounded pebbles of quartz in a matrix of small individual beds are thick, but above that particles of schist, grains of quartz, and flakes thinner beds appear and these grade upward of mica; where it rests on granite or quartz- into the shale. Abundant round or elliptical mica diorite the pebbles are also mostly quartz, spots, light buff or greenish in color, caused but the matrix is arkosic and the layers of pebbles by local reduction and removal of the fer- may be associated with deposits of arkose that ruginous pigment, are highly oharacteristio in many places merge imperceptibly with the of the Pioneer shale, and in the absence of underlying massive rock or the overlying Pio- clear structural relations serve to distinguish neer shale. These two varieties of the conglom- that formation from certain similar beds in the erate, however, are connected by transition stratigraphically higher Dripping Spring quartz- facies. The thickness of the formation varies ite. Surfaces of fresh fracture generally sparkle widely from place to place. with minute flakes of white mica. In some localities the base of the Pioneer Although the Pioneer shale is soft in com- shale may be marked only by a few sparsely parison with the conglomerates and quartzites distributed pebbles or the Scanlan conglomer- and weathers into smooth slopes, it is never- ate may not be recognizable at all. In others theless a well-indurated, firm, and in places the conglomerate attains a thickness of fully not very fissile rook. The general color of the formation as seen on the 11111 slopes is dark red, 15 feet and carries abundant well-rounded maroon, chocolate, or dull purplish gray. pebbles, including a few of quartzite derived In the Globe report the average thickness of from some ancient formation that is not now the Pioneer shale was given as 200 feet, which exposed in this region. Above this well- is about the thickness at Pioneer, in the north- defined bed, which locally resembles the eastern part of the Ray quadrangle. In the younger Barnes conglomerate, and under the ravine west of lInekberry Spring, in the south- typical Pioneer shale is a coarse arkosic sand- western part of the Ray quadrangle, the shale stone from 15 to 30 feet thick. Similar arkosic is 100 feet thick. The average thickness for material accompanies the Scanlan conglomer- that quadrangle is accordingly estimated at ate in other localities and marks a change about 150 feet. The Pioneer shale so far as in the conditions of deposition by which fine known is not fossiliferous and presents no material was laid down instead of coarse. characteristics that mark it indubitably as In the Barnes Peak section, in the northwestern marine or fluviatile in origin. It is believed part of the Globe quadrangle, the lower 25 feet to be marine and to have been deposited in of the Pioneer shale, above the Scanlan con- shallow water. No mud cracks have been glomerate, is sandy and arkosic. observed in it. SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 137 BARNES CONGLONICRATE. than at Barnes Peak, and the thickness of the The Barnes conglomerate lies stratigraph- formation is fiem 15 to 20 feet. At the north ically above the Pioneer shale and below the end of the Dripping Spring Range the con- Dripping Spring quartzite. The formation glomerate is rather variable. A small expos- was first described in the Globe report and was ure about 1i miles north of Walnut Spring shows named from Baines Pea k, in the nor! I s estern thin bands of pebbles associated with part of the Globe quadrangle, where it is from pinkish arkose and gray shale. The pebbles, 10 to 15 feet thick. There is no apparent un- which are ohiefly white quartz and not very conformity either above or below the conglom- well rounded, rarely exoeed 2 inches in diameter erate, although the abrupt change from a fine and not ank over 3 inches were seen. About shale to a deposit of coarse pebbles is indicative 2 miles northwest of Walnut Spring the sdhole formation is from 10 to 12 feet thick, but the of so extensive a modification of the conditions of erosion and sedimentation under which the arkosic matrix is- much more abundant than shales accumulated as would seem to demand a the pebbles, which although not uniformly dis- notable =conformity of contemporaneous ori- tributed are, as a rule, most numerous near the gin somewhere within the region of deposition. base. The lower part of the bed thus presents In its typical development, as near Pioneer in some places the aspect of the typical Barnes Mountain or on Silver Creek, in the Ray quad- conglomerate, but the upper part is distin- rangle, the Barnes conglomerate consists of guishable from the overlying quartzite only by smooth pebbles of white quartz and hard vitre- the oecurrenee within it of a few small and ous quartzite in an arkosic matrix. The peb- scattered pebbles. bles are generally 6 inches or less in diameter Northeast of Tam O'Shanter Peak, on the but in a few places there are some as much as 8 other hand, the conglomerate is about 40 feet inches in diameter. Although smoothly thick and consists of chiefly smooth, rounded rounded, the pebbles are not globular but are pebbles that are generally in contact with one flattened ellipsoids or round-edged disks. They another, with just enough matrix to fill the are composed only of the most durable mate- interstices. Some of the pebbles are as much rials and doubtless passed through long and as 10 inches in diameter, but most of them are varied processes of attrition before they came to under 6 inches. In the Tortilla Range, south rest in the Barnes conglomerate. On the of Kelvin, the conglomerate is about 55 feet whole, such meager evidence as is obtainable thick and contains abundant characteristic appears to indicate that the conglomerate rep- pebbles 8 inches or less in diameter. resents stream action rather than littoral or The arkosic matrix of the conglomerate is marine action. The formations that supplied generally similar to the material of the over- the quartzitic material to the conglomerate, as lying Dripping Spring quartzite, although per- will be shown later, are exposed north of Roose- haps a little coarser. It varies in hardness, but velt, in the Sierra Ancha and the Islazatzal as a rule all the constituents of the conglomer- Range. ate are cemented by silica into a hard and dura- In some places the pebbles, which generally ble rock in which fractures traverse pebbles lie with their flat sides roughly parallel to the and matrix alike. A very characteristic fea- bedding planes, are in contact and the propor- ture of the Barnes conglomerate is the pres- tion of arkosic matrix is correspondingly small; ence in the matrix of small fragments of in other places the matrix predominates. As vermilion-red chert or jasper as much as an a rule, the pebbles become larger and more inch or so in diameter. abundant toward the south, although the gra- A view of the upper part of the Barnes con- dation is probably not wholly regular. Thus glomerate as exposed on El Capiten Creek, in at Barnes Peak the average diameter of the the northeastern part of the Ray quadrangle, pebbles is 3 or 4 inches and the thickness of is shown in Plate XXVI, a the formation from 10 to 15 feet. In the DRIPPING SPRING QUARTZITE. vicinity of El Capitan Mountain, in the Mescal Range, pebbles 6 inches in diameter are abun- The Dripping Spring quartzite lies conforma- dant, the average size is probably a little larger bly on the Barnes conglomerate and under the 0 40208 -16-2 138 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. Mescal limestone.' Approximately the lower 500 feet. At Barnes Peak, in the Globe quad- third of the formation consists of hard fine- rangle, the thickness was estimated at 400 feet. grained arkosic quartzites, which, as seen in The average thickness for the Ray quad- natural sections, show no very definite division rangle is taken at 450 feet, which is probably into distinct beds but do exhibit a pronounced under rather than above the truth. striping, due to the alternation of dull-red and dark-gray:- or nearly black bands parallel MESCAL LIMESTONE. with the plane of stratification. These bands The Mescal limestone was first recognized as as a rule are less than 1 foot thick and give a a distinct formation in the course of mapping generally thin-bedded aspect to this portion of the Ray quadrangle and is named from the the formation, as may be seen from Plate Mescal Mountains, where it is well exposed. XXVII, B, although the illustration fails to Stratigraphically it is limited below by the show the contrasting tints of the bands. About Dripping Spring quartzite and above by the midway between the top and bottom of the Troy quartzite. Some fragments of this for- formation the striped beds are succeeded by mation, most of them intimately associated fairly massive beds, as much as 6 feet thick, of with intrusive diabase, occur in the Globe quad- even-grained buff or pinkish quartzite associ- rangle, but when the report on that area was ated with flaggy variegated red, brown, and prepared these masses of strata were supposed gray beds and with some layers of gray and to be somewhat metamorphosed portions of the reddish shales suggestive of the Pioneer shale. thin Devonian beds in the lower part of the In the upper part of the formation the beds "Globe limestone." become thin, fiaggy, and rusty, with a tendency In the Ray quadrangle also the Mescal lime- to grade into the Mescal limestone. stone and the diabase are closely associated. The sand which became the Dripping Spring Lying between the two heavy qttartzitic for- quartzite was deposited in shallow water and mations, the thin-bedded dolomitic limestone was at times exposed to the air, as may be proved an easy path for the invading diabase seen from the ripple marks, sun cracks, and magma and retains little of its former con- fossil worm casts visible on the surface of the tinuity. In the development of the topography beds. The deposit is tentatively regarded as the diabase tends to wear down into swales and of delta origin. It is composed throughout of hollows, and an extended view over one of fine material, and contains no pebbles, so far these depressions shows the generally olive- as known. This feature and the banding of tinted surface characteristic of diabase areas, its lower beds serve throughout the Ray quad- varied by blotches of white that represent rangle to distinguish this quart zit e from the included blocks of the Mescal limestone, some pebbly cross-bedded Troy quartzite, to be de- of which are nearly a quarter of a square mile scribed later. in area. Other portions of the formation rest Where almost vertically upturned in the in their original position on the Dripping Spring . Tortilla Range the Dripping Spring quartzite quartzite, and the diabase lies in igneous con- appears to be about 500 feet thick, but the tact, above them. Still others crop out along presence of intrusive diabase detracts a little the bases of cliffs formed by the Troy quartzite from the reliability of this measurement, as and lie above the intruded diabase. Rarely movements during the intrusion may have the limestone lies unbroken between the two increased the apparent thickness. Son t hwest quartzites. of Pioneer Mountain, where the whole of the The Mescal limestone is composed of thin quartzite -.!erns to be exposed without notice- beds that have a varied range of color, but are able fault mg, the thickness obtained by calcu- persistently cherty, the siliceous segregations lation from the width of the outcrop as mapped, as II rule forming irregular layers parallel with the average dip of the beds, and the general the bedding planes. On weathered surfaces angle of topographic slope is between 450 and these layers stand out in relief and give to the This Is a redefinition of Dripping Spring quartzite as the name was limestone the rough, gnarled banding that is originally used In the Globe quadrangle. The reasons for the change its most characteristic feature. The usual ap- have been pulgished (Min. and Mel. Press, vol. 102, pp. 747-748, 19II) and are summarized on pages 143-144 of the present paper. pearance of the Mescal limestone on outcrop- U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XXVI

eg* '

.1. BARNES CONGLOMERATE AT SOUTH END OF li. PINAL RANGE, GLOBE QUADRANGLE, ARIZ. MESCAL LIMESTONE ON EL CAPITAN CREEK, MESCAL RANGE, RAY QUADRANGLE, ARIZ., SHOWING EFFECT OF WEATHERING.

C. BARNES CONGLOMERATE, EL CAPITAN CREEK, ARIZ. U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XXVII

.1. CROSS-BEDDED PEBBLY TROY QUARTZITE, DRIPPING SPRING RANGE.

B. BANDED DRIPPING SPRING QUARTZITE, MESCAL RANGE, 1 MILE souri-i OF PIONEER. QUARTZITES OF THE RAY QUADRANGLE, ARIZ.

SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 139 ping edges is shown in Plate XXVIII. The This rock weathers brown but on fresh frac- general hue of the formation is gray or white, ture is almost white. The molecular ratio of but some beds are yellow, buff, brown, or rusty. lime and magnesia is nearly that of dolomite, In some localities the rough, gnarled strata are but as the beds are not all of the same charac- accompanied by others containing thin regular ter he foregoing analysis does not represent buff and gray layers whose differences in ehemi- t el y the composition of the whole forma- cal composition in conjunction with the dis- t ion. solving action of atmospheric water gives rise In the narrow gorge just west of Hackberry to such natural ornamentation as is illustrated Spring, in the southwestern part of the Ray in Plate XXVI, B. qit ad rtingle, the Mescal limestone stands almost Between the limestone and the overlying ve:.ticid and has a thickness of 225 feet. In Troy quartzite is a layer of decomposed vesic- tilt, section given above the total thickness ular basalt whose maximum observed thick- is stated as 220 feet, exclusive of the vesicular ness is 100 feet. Although the basalt is in basalt. This, however, is an estimate based places much thinner than this, the flow was on barometric readings corrected for a dip of apparently coextensive with the Mescal lime- about 25°. The average thickness of the stone throughout the Ray and Globe quad- formation as mapped in the Ray quadrangle rangles. Where the basalt is in contact with and including the basalt flow may be taken as the later intrusive diabase distinction be- about 250 feet. tween the two is difficult in the absence of good exposures, and in the earlier work in the TROY COJARTZITE. Globe quadrangle the altered vesicular basalt The Troy quartzite lies conformably above was supposed to be Merely a contact modifica- the Mescal limestone and below the Martin tion of the diabase.' limestone. Prior to the detailed mapping of A section of the Mescal limestone with the the Ray quadrangle this quartzite had not been overlying basalt flow, as exposed on the east recognized as a formation distinct from the side of El Capiten Canyon, is given below. lower or Dripping Spring quartzite, for in the The thicknesses stated are approximate. Globe quadrangle there are no sections that show the two quartzites separated by the Section of the Mescal limestone. intervening Mescal limestones, and such brief Troy quartzite. Feet. papers on the geology of the Ray quadrangle Vesicular basalt ...... 75 as have appeared since the Globe report was 4. Striped bud and gray dolomitic limestone weather- published have dealt only with the i ing sharp channels and ridges, as illustrated in mmediate Plate XXVI, B 15 surroundings of the copper deposits at Ray, S. Very rough cherry dolomitic limestone with no where the stratigraphic relations of the sedi- distinct division into beds. Weathers with mentary rocks are less clearly displayed than gnarly dark rusty-brown surface ...... 30 elsewhere in the quadrangle. The name of the 2. Gnarled, knotty cherty limestone, mostly dolo- mitic, in beds as much as 2 feet thick. Some formation is derived from Troy Mountain, in beds light gray and some dark brown. Shaly the Dripping Spring Range. partings ...... 125 The Troy quartzite is one of the most promi- 1. Thin impure shaly limestone, with perhaps some nent and widely exposed formations in the Ray dolomite. Splits into thin leaves. Mostly light quadrangle. The beds differ greatly in thick- gray. 50 Dripping Spring quartzite. — ness, ranging from thin flaggy or shaly layers 295 to cross-bedded pebbly beds from 25 to 50 The analysis of a sample from division 2 of feet thick. On the whole the thicker beds are the foregoing section is as follows: characteristic of the lower and middle portions Partial chemical analysis of Mescal limestone. of the formation. The upper part is inva- riably composed of thin, generally yellowish or [iieorge Steiger, analyst.] rusty worm-marked shaly quartzite indicative SiO2 ...... 29.93 of a change in sedimentation preparatory to A1203 ...... 42 Cat) 21.90 the deposition of the Devonian limestone. MgO 14.90 The most characteristic material of these 140 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. upper beds consists of layers, an inch or two I Feet. 2. Cross-bedded pebbly quartzite in beds 4 to 10 thick, of fine-grained, unevenly colored brown, feet thick. Pebbles quartz; rarely over 2 pink, and green quartzite separated by films inches in diameter; in places scattered and. of olive-gray shale whose cleavage surfaces in places concentrated in irregular lenticular are ridged and knotted with numerous worm layers. Weathers gray or rusty. Forms a casts. The quartzite layers appear almost stepped slope 25 1. Bed of irregularly banded gray quartzitic brec- dolomitic in color and texture, but the micro- cia grading up into cross-bedded coarse grit scope shows them to consist chiefly of closely or conglomerate with quartz pebbles. -Brec- fitting quartz grains with specks of flocculent via in lower part of bed contains angular limonite and little nests of a green chloritic fragments of white quartz 6 inches or less in mica. The most noteworthy features of the diameter. Forms a cliff 30 thicker beds are their generally pebbly charac- 3621 ter, which is a useful means of distinguishing isolated exposures of the Troy quartzite from Bed No. 1 is the bottom of the Troy quartz- the pebble-free Dripping Spring quartzite, and ite. Below it is the vesicular basalt at the their conspicuous cross-bedding. These char- top of the Mescal limestone. acteristics are illustrated in Plate XXVII, A. Although much of the Troy quartzite is 'While the Dripping Spring quartzite is nearly light gray or white on fresh fracture, the all arkosic the Troy quartzite shows little or weathered exposures are generally buff, brown, no feldspar. rusty, or maroon. In the canyon northwest A not quite complete section of the Troy of Tam O'Shanter Peak, where the quartzite quartzite as exposed in nearly horizontal atti- is finely exposed, the general tint is reddish tude l miles southeast of Tam O'Shanter brown, but the different parts of the forma- Peak, in the Dripping Spring Range, is given tion vary in color from white or pale huff to below, with approximate thicknesses. dull dark red. Determination of the exact thickness of the Section of Troy quartzite. Feet. Troy quartzite is difficult, owing to the fact 11. Yellowish, rusty, thin-bedded guar zites with that few of the many fault blocks show a full olive-gray shale partings roughened by worm section of the formation or give opportunity casts; at least 50 for detailed measurements. The section re- 10. Fine-grained quartzite with very regular lami- nations from 2 to 0 inches thick 11 corded above gives a total thickness of about 9. Rather thin beds of white fine-pebbly quartzite 50 3O2i feet but probably does not include all 8. A single bed of massive cross-bedded fine- the upper beds. In the gorge west of Hack- pebbly white quartzite, with layers of small berry Spring a measurement across the edges quartz pebbles every few feet. Forms a of the nearly vertical beds gave 300 feet, but, cliff 50 Sheet of porphyry, 25 feet. here also there are beds missing from the top 7. Partly concealed; apparently rather thin bed- of the formation. A little less than 2 miles ded gray pebbly quartzite 35 northwest of Tam O'Shanter Peak the forma- 6. Two beds of cross-bedded coarse quartzite or tion, here nearly horizontal, is exposed in full grit, with scattered pebbles of white quartz section between the Mescal dolomite and the as much as 6 inches in diameter. Forms a scarp 15 Devonian limestone. The mapping here indi- 5. Conspicuously cross-bedded gray quartzite, cates a thickness of a little more than 350 feet. with many layers of small quartz pebbles. On Troy and Scott mountains the quartzite as No distinct separation into beds, but obscure mapped appears to be unduly thick, the dis- laminations average about 1 foot in thick- tribution on Scott Mountain calling for a ness. Forms a stepped slope. Microscope shows typical quartzite texture with en- thickness of about 1,000 feet. This is clearly larged interlocking quartz grains 75 in excess of any possible real increase in the 4. Conglomerate with fairly well rounded peb- formation and probably is to be accounted bles, mostly of white quartz, as much as 4 for by faulting or flexing that is not distinctly inches in diameter, in an abundant cross- shown at the surface. From all available bedded matrix of coarse quartzite 6 3. Soil-covered slope, apparently underlain by a information the average thickness of the yellowish shale or fine-grained quartzite 25 formation is estimated to be about 400 feet. U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 93 PLATE XXVIII

I. TYPICAL EXPOSURE OF THE CHERTY MESCAL LIMESTONE IN THE DRIPPING SPRING RANGE, 2 MILES SOUTH OF DRIPPING SPRING RANCH.

it. STEEPLY UPTURNED MESCAL LIMESTONE WITH INTRUSIVE DIABASE IN THE TORTILLA RANGE, ABOUT 6 MILES SOUTH OF KELVIN.

MESCAL LIMESTONE IN THE RAY QUADRANGLE, ARIZ. U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XXIX

A. SECTION ON EL CAPITAN CREEK, MESCAL RANGE.

B. EL CAPITAN FROM THE NORTHWEST.

SECTIONS OF PALEOZOIC ROCKS IN THE RAY QUADRANGLE, ARIZ. SOME PALEOZOIC SECTIONS IN ARIZONA AND THEM CORRELATION. 141 The Troy quartzite, with its abundant limestone showing flaggy lamination. Above pebbly layers and conspicuous cross-bedding, this are dark-gray and yellowish limestones in is suggestive of fluviatile or deltaic deposition. beds of different thicknesses, with shaly part- The upper part of this formation, however, ings. These strata are generally fossiliferous, grades into the undoubtedly marine Devonian some of the shaly partings particularly being beds. orowded with Atrypa reticularis and other small MARTIN LIMESTONZ. Devonian brachiopods. Some very dark beds The Martin limestone occupies conformably in this upper division of the formation are the stratigraphic interval between the under- marked with an obscure mottling suggestive of lying Troy quartzite and the overlying Tornado the former presence of some of the corals which are abundant in limestone and, with the possible exception of 'pertain beds of the Martin some of its unfossiliferous lower beds, is of limestone at Bisbee but which in the Ray quad- Devonian age. The beds here separated as rangle have boon less perfectly preserved. The the Martin limestone were in the Globe quad- top bed of the Devonian is a yellow ealcareous rangle mapped with the overlying Carboni- shale which breaks up on exposure into minute ferous (Tornado) limestone under the name thin flakes and which consequently has no "Globe limestone." prominent outcrops. The yellow color is char- As a whole the Martin limestone is a com- acteristic of all natural exposures, although paratively thin bedded formation, which weath- before weathering the shale is gray. Being ers into slopes broken here and there by low overlain by the massive cliff-making Carbonif- scarps marking the outcrop of some bed a erous limestone, the bed of shale is in many little harder or thicker than the rest. A typi- places concealed by talus, and its thickness was cal natural section of the formation is shown in not exactly determined. It may be from 15 to Plate XXIX, A. Distant views of such slopes 20 foot thick, but its base is not very clearly show that the formation is divisible on the defined, for layers of similar shale occur between basis of color into two nearly equal parts. some of the limestone beds in the upper part of the formation. The prevailing hue of the lower division is light yellowish gray; the upper division, less The Devonian limestone is generally magne- uniform in tint, displays alternations of sian and does not effervesce freely in cold dilute deeper yellow and darker gray. Detailed ex- acid. An analysis of a typical specimen from amination proves the lower division to con- the lower division of the formation is as follows: sist mainly of very compact, hard, gray lime- Partial chemical analysis of Devonian limestone. stone in beds rarely more than 2 feet thick, with, at the base, a bed of impure yellow lime- pl. C. Wells, analyst.1 stone containing abundant grains of quartz. 8iO3 ...... 3. 11 This lowest bed, which in places is cross-bedded Alps ...... 33 and contains so much detrital material that it Fe203 and . FeO ...... 1. 22 CaO ...... 31.65 might be classed as a calcareous grit, weathers MgO 18.65 to a rough sandy surface, but the overlying gray beds are characterized by solution sur- Measurements and estimates of the thick- faces that although uneven in general are ness of the Martin limestone. in different parts smooth in detail. A characteristic feature of of the quadrangle range from 300 to 350 feet. these compact lower limestones is the pres- The average thiokness is considered to be ence of little spherical, oval, or irregular con- 325 feet. cretions of dark chert, which as a rule are In contrast with the older formations, which about the size of peas. No identifiable fossils have yielded no determinable organic remains, have been found in this lower division of the the upper division of the Martin limestone con- Martin limestone, although it contains obscure tains fossils at many horizons from the top of traces of organic life. the rusty bed at its base to the lower layers of About midway in the section is a bed, about the yellow shale. In all 18 lots of fossils were 15 feet thick, of rusty-yellow impure sandy collected and were referred to E. M. Bindle,

142 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916.

then of the United States Geologioal Survey, TORNADO LThrESTONZ. who lists the following species: The Tornado limestone, named from Tor- Zaphrentis sp. undet. nado Peak, in the southeastern part of the Productella hallana. Stropheodonta arcuata. Ray quadrangle, where it is extensively Stropheodonta demissa. exposed, overlies with apparent conformity Stropheodonta varistriata. the Martin limestone and is equivalent to the Stropheodonta sp. Carboniferous portion of the "Globe lime- Leptostrophia cf. L. interstrialis. stone" as mapped in the Globe quadrangle. Strophonella cf. B. ampla. Schuchertella chemungensis. In places its upper limit is a surface of erosion Schizophoria striatula. upon which in general rests the Atrypa reticularis. Gila conglomerate, although in the south- Atrypa hystriz occidentalis. Atrypa spinosa. eastern part of the Ray quadrangle there is Camarotcechia. sp. an intervening andesitic formation, probably Pugnax Pugnua• of Mesozoic age. Spinier orestes. The Tornado limestone is generally light Spirifer hungf)rfordi. Cyrtia cyrtiniformis. lead-gray in color and is divisible with respect Schizodus sp. to thickness and character of bedding into at Paracyclas cf. P. elliptic*. least three members. The basal division, Euomphalus cyclostomus? directly overlying the Devonian, is about 75 Euomphalus up. Bellerophon sp. undet. feet thick and forms the lower part of the scarp that is so prevalent a feature of the Dr. Kindle remarks with reference to this fauna: Carboniferous outcrops in central and southern Arizona. Under the action of erosion this On the ground of its close relationship to an Upper De- vonian fauna of Iowa and its stratigntphic relations to tho division behaves as a single massive bed, but Carboniferous fauna of the Arizona section, I would place in reality it is made up of alternating dark the fauna of the Martin limestone and its equivalent, the and light gray layers, a foot or two thick Devonian fauna of the Ray quadrangle, in tho Upper which in cliff faces give this member a banded Devonian. It is of course poasible that the time range of appearance, as may be seen in Plate XXIX, A this fauna in Arizona may include Middle as well as Upper Devonian, but that it, includes the Upper Devonian in any (p. 141). This banded division with a few event seems well established by the available evidence. transitional beds at its top is succeeded by a As the Devonian portion of the "Globe lime- very massive member, folly 100 feet thick, stone" in the Globe quadrangle is continuous within which, as exposed in cliff faces, there and identical with what is now designated the is as a rule little more than a suggestion Martin limestone, fossils collected from it of divisional bedding planes. This massive should be included. in the Martin fauna. For member (Pl. XXIX, A) is of lighter and convenience therefore the list of determine; more uniform tint than the basal metnber. thins made by H. S. Williams ' on the older The two together constitute the principal • collections, with slight changes by Dr. Kindle, cliff-forming part of the Carboniferous lime- to bring it into accord with present, nomencla- stone. The third division consists of beds ture, is given below. generally thinner than those in the other Cf. sponge. two divisions but not separable from them by Cf. Rhodocrinus, crinoid stems and plates. any marked lithologic distinction. Atrypa reticularis Linn. The Tornado limestone consists essentially Prod uctella hal tuna Walcott. of calcium carbonate and effervesces freely Stropheodonta calvini Miller. in dilute acid. An analysis of a typical sample Cyrtia cyrtiniforntim Mall and Whitfield). Spirifer hungerfordi is as follows: Spirifer oremtem !fall and Whitfield. Partial chemical analysis of Tornado limestone. whitneyi I lull. Spirifer [W. 1'. Schaller, analyst.] Retiettlaria finibriata (Conrad). 1. 36 Cyrtina ham ilionensis I fall. . 22 Martinia en bum ( L lall); il. Spirifer infima F4(‘': 1(14))13 54. 91 Whitlborne. 21 Pugnax pugnum ( Martin). Syliuchertella eltenitingensim (Conrad) var. Thifilgninyers of calcareous shale separate Dielamina cf. D. calvini h ull and Whitfield). some of t he beds, hut these are a very subor- itanmome, U. S. geol. Survey Prof. Paper 12, pp, .101-42, 1903. dinate part, of the formation. SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 143 Although nearly all the Carboniferous lime- sissippian in the Ray quadrangle, therefore, cor- stone contains fossil remains, there are few responds to the Escabrosa limestone at Bisbee, localities where full and satisfactory collections and the Pennsylvanian limestone near Ray to can be made. The beds of the two lower the lower part of the Naco limestone. divisions carry abundant fragments of crinoid In the Bisbee quadrangle the distinction stems and less numerous rugose corals with between the Mississippian and Pennsylvanian long-winged spirifers and Rhipidomella. These limestones proved practicable, although the appear in silicified form on weathered surfaces plane of demarcation is not definite. In the of the rock, but they can not readily be sep- Ray quadrangle a similar distinction might arated from their matrix. In the upper possibly be made, but no satisfactory basis for division appear different species of Productus it appeared in the course of the field work, and and Spirifer, Deriver, crassa, Composita subtilita, it is doubtful whether its accomplishment and Fusulilla• would be worth the additional labor involved. Of seven collections made at as many dif- The cliff-making lower members of the Tornado ferent localities in the Ray quadrangle, four, limestone are certainly Mississippian, and according to George H. Girty, of the Geological probably a considerable part of the upper Survey, consist of Mississippian forms, and member also belongs to that epoch. three of pennttylvanian forms. His determina- The original thickness of the Tornadò lime- tions of these fossils are as follows: stone is unknown, for the formation was ex- tensively eroded before the eruption of the ppian fauna. andesitic lavas and before the deposition of Syringopora settleata Girty? the Gila conglomerate. In the vicinity of Menophyllum sp. Tornado Peak and along the east flank of the Amplexus? sp. Tortilla Range the limestone at present must Rhipidomella alt. R. owen1 Hall and Clarke. Rhipidomella dubio lien? be fully 1,000 feet thick, and it may at one Leptoma analogs, Phillips. time greatly have exceeded this thickness. Schuchertells, iulls,Us White and Whitfield? Chouetes sp. NOMZNCLATURE. Avonia *remit& hall? The foregoing descriptions have been written Counarotcechia metallic& White. Miasma burlingtonense White. with special reference to the formations as they Spiriter centronatue Wiuchell. are displayed in the Ray quadrangle, but they Brachythyrio peculiaris Shumard. apply without essential change to the adjoining Spiriierina solidirostris White. Globe quadrangle. When that area was stud- Syringothyris sp. ied, about 11 years ago, little was known of the Composite humilis Girty? Cliothyridino sp. stratigraphy of this part of Arizona and it appeared impracticable, in so intricately faulted refilieylvanian fauna. a district, to map the sedimentary rocks in as natal* sp. great detail as has since proved possible in the Derby* crassa Meek and Hayden. Ray quadrangle. In the Globe report the Productus semireticulatus Martin. Scanlan conglomerate, Pioneer shale, Barnes Productus cora D'Orbigny. Pustule semipunctata Stevens. conglomerate, and Dripping Spring quartzite, Spinier e.ameratus Morton. while distinguished in certain geologic sections, Spinier boonensis Swallow? were mapped together as the "Apache " Composite subtilite Hall. and the Devonian and Carboniferous limestone Myalina subquedrata Shumard. were mapped as the "Globe limestone." As According to Mr. Girty, the older of these two none of the numerous small fault blocks into faunas is early Mississippian and the other is which the Globe district is divided afforded a early Pennsylvanian. He notes that the con- complete geologic section, and as no quartzite ditions exhibited in the Ray quadrangle are was found overlying limestone, all the quartz- apparently similar to those at Bisbee, where a ite was supposed to belong to one formation limestone of probable early Pennsylvanian age (the Dripping Spring quartzite), and all. the (the Naco) rests directly on a limestone of early limestone was supposed to belong to the Mississippian ago (the Escabrosa). The Mis- Devonian and Carboniferous "Globe lime- 144 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. stone." The "Globe limestone," as mapped, trusion of granodiorite at Troy, in the Ray therefore included a little Mescal limestone, quadrangle, also. The metamorphism there, and the Troy quartzite was not distinguished however, is on a much smaller scale than in from the Dripping Spring quartzite. Had the the Santa Catalina Range. Overlying the existence of the Mescal limestone and Troy schist in the vicinity of Apache is the Barnes quartzite been known when the Globe report conglomerate, showing its well-founded ellip- was written, these two formations would soidal pebbles. Its thickness here is about 12 probably have been included in the definition feet. Although it is more silicified than the of the Apache group. typical conglomerate of the Ray quadrangle, As at present constituted, this group consists there can be little doubt of its stratigraphic of the following formations, named in ascending identity. Southeast of Apache, on the east order: Scanlan conglomerate, Pioneer shale, slope of the range, the Barnes conglomerate is Barnes conglomerate, Dripping Spring quartz- overlain by a quartzite which is correlated with ite, Mescal limestone, and Troy quartzite. All the Dripping Spring quartzite, although its are apparently conformable and are provision- character has been modified by the prevalent ally assigned to the Cambrian. metamorphism. Stratigraphically above the quartzite is a formation that is probably the SANTA CATALINA GEOLOGIC SECTION. Mescal limestone. In a few places the lime- As the Santa Catalina Range, northeast of stone shows some of the cherty bands so char- Tucson, is being carefully studied by Prof. C. acteristic of this formation near Ray, but as a F. Tolman, jr., for the United States Geologi- rule the beds are much metamorphosed. Some cal Survey, and as my own observations were have been squeezed and kneaded so that the confined to an excursion of only six days' dura- chert layers have been drawn out into thin curly tion, under his guidance, the treatment ac- lamina); others have been changed to crystal- corded in this paper to the geology is necessa- line schist or to fine-grained garnet-epidote rily brief and general. rock. The vesicular basalt that overlies the The central feature of the range, as worked Mescal limestone in the Ray quadrangle was out by Mr. Tolman, is a great post-Carbonifer- not recognized in the brief examination made ous intrusive mass oi siliceous muscovite gran- of the Catalina Range. ite modified to a gneissic rock near its margins, Above the Mescal limestone is a pebbly surrounded by a zone of intense contact meta- quartzite with bands of conglomerate and morphism in which rocks of widely different with thin, shaly worm-marked beds near the kinds have been conspicuously affected. The top; in all probability this is the Troy quartzite. oldest rock cut by this granite is a coarse, por- The quartzite is overlain by generally rather phyritic biotite granite which, apparently as thin bedded Devonian limestones, from which a result of the later granitic intrusion, grades Mr. Tolman has collected fossils, followed in into augen gneiss, and locally this rock in turn ascending stratigraphic succession by the has been transformed into a thinly fissile schist. thicker-bedded gray Carboniferous limestone. Resting upon a worn and weathered surface Finally, these formations are unconformably of the pre-Cambrian granite, as may be well overlain by a thick series of red shales, contain- seen on the east side of Oracle Ridge, north of ing some impure sandy limestone, with a heavy Apache, is the Scanlan conglomerate, 10 to 12 limestone conglomerate at the base. These feet thick, compdsed of imperfectly rounded beds may possibly belong to the Manzano pebbles of white quartz in a much silicified group,' but Mr. Tolman has not yet found any matrix. The conglomerate grades upward fossils in them. through 'several feet of very hard white quartz- In the short time devoted to the Santa Cata- ite into fine-grained sericite schists--the locally lina Range no attempt was made to measure metamorphosed Pioneer shale. In some locali- the thicknesses of the different formations. ties in the Santa Catalina Range the crystalline Dist Grl)tmcil And metamorphism render this a texture is so well developed that these altered difficult task, but Mr. Tolman will doubtless shales might easily be mistaken for the pre- attempt it before the completion of his work. Cambrian Pinal schist. It may be noted in The general impression obtained, however, was this connection that the Pioneer shale has been I1 , W. T., end Girty, 0.11., The Menzano group of the Rio Grande metamorphosed to crystalline schist by the in- valley, N Max.: U.S. Geol. Survey Dull. 389, 1909. SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 149

The other lots add several species to this fauna, espe- Section of Longfellow limestone one-fourth mile south of cially one or two large species of Schizostonia, a large Bel- Modoc Peak, lerophon, possibly B. majusculus, and a Murchisonia re- Feet. Buff limestone ...... 15 sembling M. terebra. Quartzitic sa...dstone ...... 10 These two Pennsylvanian faunas bear a close relation- Bluff of brownish-gray cherty limestone ...... 140 ship to the faunas of the Magdalena limestone and Man- Shaly liniesto7i it seems highly probable T 90 zano group of New Mexico, and Coarse gray eau .,d9ne ...... that the upper Naco limestone will correlate with the 10 Sandy and shaly „0::Attone (base)...... 115 Manzano and the lower Naco with the Magdalena. The fauna of the upper Nam is'also related to a fauna 380 found in the middle or upper part of the Hueco limestone. The lower Hueco fauna, while resembling in some respects Fossils are scarce in the Longfellow lime- that of the lower Naco, contains a good many species not stone. In the lower shaly part were found a yet found in the latter, and I am unable to state whether few small lingulas and other forms that, while we have merely the same fauna with regional modifica- tions or two faunas, one of which is older than the other. insufficient for a certain determination of age, I rather incline to the former belief. were regarded by Dr. C. D. Walcott as in- dicating probably the uppermost part of the The thickness of the Naco formation at Cambrian. Near the top a the formation Tombstone has not been measured, but proba- were found gastropods and fragments of tri- bly amounts to several hundred feet. The lobites which E. 0, Ulrich determined as early limestone was extensively eroded before the .' Lindgren places the Coronado deposition of the Mesozoic beds that uncon- quartzite in the Cambrian and the Longfellow formably overlie it in part. limestone in the Ordovician.' Resting upon the Longfellow limestone is CLIFTON GEOLOGIC SECTION. the Morena shale, consisting of a lower divi- At Clifton, 90 miles east-southeast of Globe,' sion of compact argillaceous limestone 75 feet about 1,500 feet of apparently conformable thick and an upper division of dark clay shale Paleozoic beds rest unconformably on Pina1 about 100 feet thick. A few fossils were found schist and coarse red granite. At the bottom in the lower division and were referred pro- of the stratigraphic column is the Coronado visionally by Prof. H. S. Williams to the quartzite, 200 feet thick, with a layer of con- Devonian.° glomerate at its base as much as 50 feet thick. Overlying the Morenci formation is the A section of the quartzite southwest of Morenci Modoc limestone, 180 feet thick, of Mississip- is described by Lindgren' as follows: pian age.; North of the exposures of the Modoc limestone and not in contact with it is a lime- Section of Coronado quartzite. stone formation 500 feet thick which Lindgren ...... Feet. White quartzitic sandstone 50 has called the Tub e Spring limestone. It carries Banded pink and maroon quartzitic sandstone, form. both Mississippian and Pennsylvanian fossils, big . precipitous bluff ...... 102 and the lower 200 feet of the formation is re- Quartzitic conglomerate 10 Sandstone...... 3 garded by Lindgren as in a general way equiva- Quartzitic conglomerate (pebbles l'inch in . diameter) ...... 8 lent to the Modoc limestone. The Tide Spring Coarse sandstone (base) ...... 10 limestone is limited above by the pre- unconformity. 243 ROOSEVELT GEOLOGIC SECTION. Above the Coronado quartzite lies the Longfellow limestone, 200 to 400 feet thick, The gorge through which Salt River, after which consists of cherty limestone in the passing the Roosevelt dam, traverses the south upper part grading downward into shaly beds end of the Mazatzal Range (see PI, XXXI), near the base. One of the sections given is as affords an excellent section of the beds from follows: the Mississippian down to the granite. This

I Lindgren, Waldemar, The copper deposits of the Clifton-Morenci Op. cit. (Prof. Paper 43), p. 63. district, Aria.: U. S. Geol. Survey Prof. Paper 43, 1903. See also U. EL Idem, p. 59. Oeol Survey Geol. Atlas, Clifton folio (No. 129), 1906. Idem, p. 09, 'Op. Wt. (Prof. Paper 43), p. 60. Idem, p. 72 (list of fossils).