SOME PALEOZOIC SECTIONS IN ARIZONA AN:D THEIR CORRELATION. 

By FREDERICK LESLIE RANSOME. 

PURPOSE AND SCOPE OF PAPER. 

During the last 16 years detailed geologic 

work has been done in a number of mining districts in Arizona, several reconnaissance reports 

have added to our knowledge of the geology of 

the State, and sections of Paleozoic and older 

rocks in the Grand Canyon and at Globe, Ray, 

Clifton, Tombstone, and Bisbee have been 

carefully studied; but hitherto the investigations in most of these fields have been unconnected by reconnaissance examinations of 

intervening areas. Realization of this lack of 

correlation led, in 1912, to a preliminary 

reconnaissance of the country extending northwestward from Globe to Jerome,· in the hope 

that light might thereby be thrown on the 

nature of the changes that connect the wellknown stratigraphic section of the Grand Canyon with the very different succession of beds 

at Globe. A visit to the Santa Catalina Range, 

northeast of Tucson, in company with Prof. 

C. F. Tolman, jr., who is preparing the Tucson 

folio for the United States Geological Survey, 

afforded an opportunity of partly closing the 

gap of terra incognita between Ray and Tombstone. Detailed work on the Ray quadrangle, 

the full results of which are not yet pub]ished, 

has supplied the materials for a much more 

accurate description of the geologic column in 

central Arizona than was heretofore possible, 

and similar work in the Tombstone district 

has extended the Bisbee section northward. 

Finally, some additional reconnaissance has 

been made of the Mazatzal Range and the 

Sierra Ancha. 

The present paper includes (1) a brief introductory outline of the broad topographic features of the State, (2) a description of the full 

and very satisfactorily exposed geologic section of the Ray-Globe region, with less detailed 

accounts, in part abstracted from the literature, 

of other stratigraphic sections to the southeast 

and northwest, and (3) a discussion of the correlation of these sections from the Grand Canyon, 

in the northwestern part of the·State, to Bisbee, 

near the Mexican border. 

The positions of the sections discussed may 

he seen by reference to the outline map (Pl. 

XXIV) and to the diagram accompanying the 

correlation chart (Pl. XXV, p. 136). 

TOPOGRAPHIC PROVINCES OF ARIZONA. 

The State of Arizona may conveniently be 

divided into three topographic regions-the 

plateau region, the mountain region, and the 

desert or bo1son region. The plateau region, 

which has tLll area of about 45,000 square 

rniles, occupies the northeastern part of the 

State and drains generally northward through 

the Little Colorado and smaller streams into 

the Grand Canyon. The general altitude of 

this region, which is a portion of the great 

Colorado Plateau, ranges from 7,000 to over 

8,500 feet. As Dutton graphically describes it, 

Its strata are very nearly horizontal, and with the exception of Cataract Canyon and some of its tributaries it is 

not deeply scored. Low mesas, gently rolling and usually 

dad wit h an ample growth of pine, pinon, and cedar; 

broad and shallow valleys, yellow with sand or gray with 

sage, repeat themselves over the entire area. 

Here and there the Kaihab (Pennsylvanian) · 

limestone, th1~ prevalent surface rock, is covered 

by flows of basalt or hears erosion remnants of 

younger stra1 a, and above it, north of Flagstaff, 

rise the lofty extinct volcanoes of· the San Franc:isco Mountains. 

The southwestern limit of the plateau traverses the State in a general southeasterly direction from the Grand Wash Cliffs, near the 

eastern border of Nevada, to the New Mexico 

line, a few miles northeast of Clifton.1 This 

t Dutton, C. E., Tertiary history of the Grand Canyon district: U.S. 

Geol. Survey Mon. 2, p. 14, 1882. 

133 
134 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

boundary along much of its course is a single 

bold cliff 2,000 feet or more in height, but elsewhere it is less definite or simple, owing to a 

distribution of the total difference in relief 

among a series of great topographic steps or to 

local accumulations of volc~nic ·tocks', especially basalt. In general the outer or lower 

line of cliffs separates nearly horizontal and 

undisturbed strata on the northeast from 

faulted and tilted beds on the southwest, and 

locally, as along the Grand Wash Cliffs, this 

line is itself a fault scarp, more or less modified 

by erosion. 

The Grand Wash Cliffs rise precipitously 

3,000 feet or more above the plains to the west. 

According to Lee/ pre-Cambrian granite is exposed at their base and the Redwalllimestone 

forms their crest and the floor of the adjacent 

plateau. About 45 miles east of the Music 

Mountains a second gigantic step, that of the 

Aubrey Cliffs, north of Seligman/ carries the 

geologic section nearly to the top of the Kaibab 

(Pennsylv_anian) limestone, which forms the 

surface of the Coconino Plateau, south of the 

Grand Canyon. South of the Music Mountains there is another ample terrace in the 

ascent from the valleys of the mountain region 

to the Colorado Plateau-that of the Truxton 

Plateau. This bench, which lies between the 

Cottonwood and Aqui1rius cliffs to the west 

and the Y ampai Cliffs and Juniper Mountains 

to the northeast, is described by Lee~ as a 

granitic peneplain partly covered with volcanic 

rocks. 

South of Ash Fork the continuity of the 

pl.ateau escarpment is interrupted by flows of 

basalt that poured down from the plateau to 

the valley of the Verde, forming a slope that 

has been utilized by the Santa Fe, Prescott & 

Phoenix Railway between Ash Fork and 

Jerome Junction. East of this railway and 

north of Jerome the edge of the plateau is in 

general a scarp (part of the Aubrey Cliff of 

Gilbert 4 ) over 2,000 feet in total height, with 

deep reentrants and bold pinnacled promontories. East of Camp Verde a thick series of 

basaltic flows with associated tuffs has cov1 Lee, W. T., Geologic reconnaissance of a part of western Arizona: 

U. S. Geol. Survey Bull. 352, p. 19, pl. 1, 1908. 

2 See Darton, N. H., A reconnaissance of parts of northwestern New 

Mexico and northern Arizona: U. S. Geol. Survey Bull. 435, p. 8, pl. 1, 

1910. 

a Op. cit., p. 21. 

~U.S. Geol. Surveys W.looth Mer. ~ept , vol. 3, p. 49, 187a. 

ered the edges of the nearly horizontal sedimentary rocks; but these beds appear again 

at the head of Fossil Creek and continue eastward past Payson in the great southwardfacing cliff that marks the descent of about 

2;000 feet · from . the Mogollon Mesa to the 

Tonto Basin. From Fort Apache eastward to 

the New Mexico line the plateau boundary 

becomes less distinct. Erosion has partly de-

. stroyed its continuity, and vast accumulations 

of volcanic rock have obscured the original 

plateau surface. ' 

The second topographic division, the mountain region, which adjoins the plateau region 

on the southwest, is essentially a broad zone 

of short nearly parallel ranges, among which are 

the Dragoon, Chiricahua, Whetstone, Pinaleno, 

Galiuro, Santa Catalina, Pinal, Superstition, 

Ancha, and Mazatzal, extending diagonally 

across the State from the southeast corner to 

Colorado River. The width of this zone may 

be taken as from 70 to 150 miles, but its southwest boundary is not susceptible of precise demarcation. Few of the individual ranges exceed 50 miles in length or 8,000 feet in altitude. 

Their general trend is almost northwest, but 

near the Mexican border it becomes more nearly 

north, and the mountain zone as a whole coalesces with a belt of north and south ranges that 

extends through New Mexico and borders the 

plateau region on the east. 

Most of these ranges consist mainly of quartzites and limestones of Paleozoic or earlier age, 

resting with conspicuous unconformity upon 

granitic, gneissic, · and schistose rocks. All 

these rocks are cut by later intrusives, especially by diabasic and monzonitic rocks, and 

are partly covered by flows of lava. Structurally these ranges are characterized by the 

dominant part played by faulting as compared · 

with folding. The great copper deposits of 

Arizona, so far as they are known, are all, except that at Ajo, within this mountainous 

zone. 

Adjoining the mountain region on the southwest is the third topographic division, the desert 

region, which also contains numerous short 

mountain ranges of prevalent northwesterly 

trend. In this region, however, most of the 

ranges are separated by broad desert plains 

underlain by fluviatile and lacustrine depocsits 

of late geologic age, or by undulating granitic 
U. S. GEOLOGICAL SURVEY 

ll!l 

' ' 

l 

Scllle~ 

Drawn from G~t'ral U.nd Office and u. ro•t Otf,ce ,..,. leat.ional foruu fromJitut pro<lamation). ( APfil, 191&) 

t'1AP OF ARIZONA. 

PROFESSIONAL PAPER 98 PLATE XXIV 

AVAJO 0 

/_\/ ··~ IINT'IIAN RE;';\ -s 

·- ·- ~ ~;-> '-·· -·- ~ 

BLA!.:K 

109" 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATIOK. 135 

lowlands partly covered with gravels and flows 

of lava. 1 The boundary between the mountain and desert regions is, as previously stated, 

indefinite but may provisionally be taken as a 

curved line extending from Nogales, on the 

Mexican frontier, past Tucson and Phoenix to 

Needles, near the California line. The main 

drainage lines of both regions are transverse to 

the trend of the ranges, the run-off finding its 

way through Gila and Williams rivers into the 

Colorado. The minor streams, many of them 

intermittent, occupy in general the valleys between the parallel ranges. 

RAY-GLOB~ GEOLOGIC SECTION. 

GENERAL FEATURE~ . 

The Ray and Globe quadrangles, as may be 

seen from the diagram on Plate XXV, are in 

south-central Arizona, and the Ray quadrangle 

lies immediately south of the Globe quadrangle. 

They include the Pinal Range and parts of the 

smaller Mescal, Dripping Spring, and Tortilla 

ranges. The relative positions of these ranges 

are shown in the outline map of Plate XXIV. 

The rocks are intricately faulted, the fault 

pattern being on an extraordinarily minute 

scale, and the stratified rocks have been extensively invaded by diabase. Nevertheless, excellent sections, of the kind illustrated in Plate 

XXIX (p. 141), may be studied in the Mescal 

Range and in many of the larger fault blocks 

of the Dripping Spring Range. The total 

thickness of the beds below the base of the Carboniferous limestone and above the preCambrian crystalline rocks is about 1,600 feet. 

The Carboniferous limestone is at least 1,000 

feet thick and is limited above by a Mesozoic 

erosion surface. No evidence of angular unconformity has been detected within the Paleozoic sedimentary series in the Ray quadrangle, 

although the exposures are so good that any 

appreciable angular discordance could scarcely 

escape recognition. 

PINAL SCHIST. 

The Pinal schist and intrusive batholithic 

masses of granite and quartz-mica diorite are 

the fundamental rocks of the Ray-Globe region. 

The name Pinal schist was ·first applied in 

1903 2 to the pre-Cambrian schistose terrane 

1 Antisell, Thomas, U.S. PacifieR. R. Expl., vol. 7, pt. 2, pp.130-138, 

1857. 

2 Ransome, F. L., Geology and ore deposits of the Globe copper district, Ariz.: U. S. Geol. Survey Prof. Paper 12, p. 23, 1903. 

of the Globe quadrangle, the geographic term 

of the designation being derived from the Pinal 

Mountains, on whose slopes the schists are 

extensively exposed. As was then pointed 

out, these rocks probably correspond to what 

Blake 1 20 years earlier had called the "Arizonian slates," but as the geographic term of 

his name did not accord with the principles of 

nomenclature followed by the Geological Survey and as his lithologic term was not appropriate for crystalline schists, that designation 

could not well be retained. Since the publication of the Globe report the name Pinal schist 

has been applied to the pre-Cambrian crystalline schists of the Clifton-Morenci 2 and Bisbee 3 

districts. This formation has of late years attained economic importance as the principal 

country rock of the disseminated copper deposits at Ray and Miami. 

Most of the Pinal schist is light gray to 

blue-gray in color and has a more or less satiny 

luster on the cleavage surface. In texture it 

ranges from cryptocrystalline sl.aty sericitic 

schist through fine-granular fissile rocks to imperfectly cleavable, coarsely crystalline quartzmuscovite schist carrying andalusite or sillimanite. The coarsely crystalline varieties occur chiefly in the vicinity of granitic intrusive 

masses and grade into the less intensely metamorphosed varieties that make up the bulk of 

the formation and are cbaracteristic of most 

of the exposures in the Ray quadrangle. 

In the vicinity of Ray and west of that town 

a considerable part of the schist is a gray finegrained, moderately fissile rock that has the 

unmistakable aspect of a squeezed and metamorphosed sandstone. Thin sections of this 

variety, seen under the microscope, show 

rotund but irregular grains of quartz as much 

as 5 millimeters in diameter in a groundmass 

consisting chiefly of quartz and sericite. The 

large quartz grains show the effects of granulation with more or less recrystallization under 

pressure. 

Associated with those schists that are clearly 

of sedimentary origin are very subordinate 

masses of greenstone schist and other varieties 

that were originally igneous rna terial. 

1 Blake, W. P., Geology of the Silver King mine: Eng. and Min. Jour., 

vol. 35, pp. 238-239, 1883 . 

. 2 Lindgren, Waldemar, The copper deposits of the Clifton-Morenci . 

district, Ariz.: U. S. Geol. Survey Prof. Paper 43, p. 56, 1905. 

a Ransome, F. L., The geology and ore deposits of the Bisbee quadrangle, Ariz.: U. S. Geol. Survey Prof. Paper 21, p. 24, 1904. 
136 SHORTER · CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

SCANLAN CONGLOMERATE. 

At the base of the sedimentary column at Ray 

(see Pl. XXV) is the Scanlan conglomerate, 

first described in the Globe report, where it 

was said to be from 1 to 6 feet thick and composed of imperfectly rounded pebbles of vein 

quartz with scattered flakes of schist held in a 

pink arkosic matrix. The Scanlan conglomerate is locally the most variable of all the 

Paleozoic formations, both in constitution and 

in thickness. It was evidently formed, with 

little transportation, from the materials that 

the waves of an advancing sea found lying on a 

well-worn ancient surface of low relief. Areas 

of schist were littered with fragments of white 

vein quartz, and the upper parts of granitic 

·masses were deeply disintegrated. Consequently 

the basal conglomerate where it rests on the 

Pinal schist is composed chiefly of imperfectly 

rounded pebbles of quartz in a matrix of small 

particles of schist, grains of quartz, · and flakes 

of mica; where it rests on granite or quartzmica diorite the pebbles are also mostly quartz, 

but the matrix is arkosic and the layers of pebbles 

may be associated with deposits of arkose that 

in many places merge imperceptibly with the 

underlying massive rock or the overlying Pioneer shale. These two varieties of the conglomerate, however, are connected by transition 

facies. The thickness of the formation varies 

widely from place to place. 

In some localities the base of the Pioneer 

shale may be marked only by a few sparsely 

distributed pebbles or the Scanlan conglomerate may not be recognizable at all. In others 

the' conglomerate attains a thickness of fully 

15 feet and carries abundant well-rounded 

pebbles, including a few of quartzite derived 

from some ancient formation that is not now 

exposed in this region. Above this welldefined bed, which locally resembles the 

younger Barnes conglomerate, and under the 

typical Pioneer shale is a coarse arkosic sandstone from 15 to 30 feet thick. Similar arkosic 

material . accompanies the Scanlan conglomerate in other localities and marks a change 

in the conditions of deposition by which fine 

material was ·laid down instead of coarse. 

In the Barnes Peak section, in the northwestern 

part of the Globe quadrangle, the lower 25 feet 

of the Pioneer shale, above the Scanlan conglomerate, is sandy and arkosic. 

PIONEER SHALE. 

In the Globe report the name Pioneer shale 

was given to a series of shaly beds that overlie 

the Scanlan conglomerate and underlie the 

Barnes conglomerate. The typical section is 

that exposed on the northeast slope of Pioneer 

Mountain. 

In most places the Pioneer formation consists 

of dark reddish-brown, more or less arenaceous 

shales composed largely of fine arkosic detritus 

with little or no calcareous material. In soml 

beds fragments of pink feldspar are easily 

recognizable with the .unaided eye, and as a 

rule the shales toward their base grade into 

arkosic grits. These arkosic basal beds are 

well developed in the Apache Mountains, just 

northeast of the Globe quadrangle, where they 

attain a thickness of approximately 175 feet. 

Up to a horizon 75 feet above the granite the 

individual beds are ~hick, but above that 

thinner beds appear and these grade upward 

into the shale. Abundant round or elliptical 

spots, light buff or greenish in color, caused 

by local reduction and removal of the ferruginous pigment, are highly characteristic 

of the Pioneer shale, and in the absenoe of 

clear structural relations serve to distinguish 

that formation from certain similar beds in the 

stratigraphically higher Dripping Spring quartzite. Surfaces of fresh fracture generally sparkle 

with minute flakes of white mica. · 

Although the Pioneer. shale is soft in comparison with the conglomerates and quartzites 

and weathers into smooth slopes, it is nevertheless a well-indurated, fum, and in places 

not very fissile rock. The general color of the 

formation as seen on the hill slopes is dark red, 

maroon, chocolate, or dull purplish gray. 

In the Globe report the average thickness of 

the Pioneer shale was given as 200 feet, which 

is about the thickness at Pioneer, in the northeastern part of the Ray quadrangle. In the 

ravine west of Hackberry Spring, in the southwestern part of the Ray quadrangle, the shale 

is 100 feet thick. The average thickness for 

that quadrangle is accordingly estimated at 

about 150 feet. The Pioneer shale so far as 

known is not fossiliferous and presents no 

characteristics that mark it indubitably as 

marine or fluviatile in origin. It is believed 

to be marine and to have been deposited in 

shallow water. No mud cracks have been 

observed in it. 
U. ::; GEOLOGICAL SURVEY 

I 

BISBEE..,.__ 

Ransome,F.L. 

JU.::i 01je<Jioig'cal Survey 

Paper 21, 

', 

''<"o 

0..,/. ~ .• 

' ' ' ' Glance conglorr,erate and c-verlying \ 

formations, all of Comanche age \ 

Naco limestone 

3,000feet 

Plus unknown thic knes5 removed by eros 1on. 

Chiefly lig ht-gray, wh ite, and 

pinkish beds of moderate 

th ckne~s. 

Abu(ldant fossils 

Escabrosa limestone 

700 feet 

Thick-bedded, white and lightgray rimeston e. 

Fossiliferous 

Martin limestone 

340feet Dark-~ray limestone)n moderaiely 

th1cK bees vv it h some snale. 

Fossil iferous in upper half 

Abr· igo limestone 

770feet 

Th in-bedded impure, in part 

shal>', in part. a_rer:aceous}very 

cherty do lom rbc i 1mestone 

Carries Middle Cambr ian fossils . 

Bed of white quartzite about 

8 feet thick at top 

Bolsa q u artzite 430 feet, 

Cross-bedded _and pebbly. !n moderately thrck beds.Layerof 

conglomerate at b.ase 

\ 

\ 

\ 

I II \ 

TOMBSTONE ....,._ ~.:::-

-....... -...... 

' ' " " ' " " ' " " '\ 

' 

Beds as yet unnamed . whose . \ 

position IA'Ithin the Mesozoic col~ \ 

umn is uncertain \ 

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' ' ' ' ' ' ' '\ 

'\ 

'\ 

' 

GENERALIZED COLUMNAR SECTIONS 

OF THE 

PALEOZOIC STRATA OF ARIZONA 

FROM MEXICO TO THE GRAND CANYON 

Compiled by F.L.Ransome 

1916 

VERTI CAL SCALE 

5~00:=c=~==~~==~===============5£00============~~000 FEET I 

' I 

I ' /'0 

Naco limestone 

(Thickness not measured . 

Probably about the same as at Bisbee) 

Same general character as at 

Bisbee 

Esca brosa limest one 500feet 

(approximate only) 

Thick-bedded white and light- g ray limestone. 

f'cssil iferous 

Ma rtin limeston e 340feet 

Dark-gray fossiliferous limestone 

with some soft shale 

Abrigo limestone 

rOO f eet 

T hin-bedded impure cherty 

I imestone w ith shaly and 

sandy I ayers. 

Bed of white quartzite about 

5 feet thick at top 

Bolsa quart zite 

440feet 

Ha rd quartzite in beds up to thick . Small scattered pebble> 

Thin conglornerate at base 

I 

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GLOBEAND RAY f QUADRANGLES ~·:;:::-,------ ; Ransome, F.L. ' . ,washington Academy of Sciences ', 

1 Journa . \ 1 va l. 5, pp. 380-388 \ 

1 1915 \ 

I \ 

I ~ I 

I 

I 

?. 

"/ 

~ 

Andesite,ande5ite breccia, and tuff \ 

~::;...~f.1=-~f---- UNCONFORMITY \ 

Tornado limestone 

l,OOO+feet 

Thick bed5 of light-gray limestone . 

fossils scarce in lower or Mississippian portion but plentiful in Penn- sylvanian portion. 

nr I 

J / 

No recog~ iz ab e pla~e of d ivi5ion 

bet ween Mississippian and 

Pennsylvanian 

CLIFTON 

After Li ndg ren,W. 

U.S.Geo logical Survey 

Folio IZ9, 

1905 

Pin ka rd fo r mation 

Shale and sandstone of Benton 

age UNCONFORMITY 

Tule Spring limest one 500l'eet 

(Include? some Mississippian) 

Thick-bedded blue-gray limestone 

Modoc limest one 180 feet ~? r 100 feet pu re thick-bedded 

lrmestone; lower 80feet do:omitic 

in part, with one bed of sandstone 

Cherty limestone, locally dolomitic. 

Lower 250 feet thinner-bedded, 

l.'.rith considerable shale. Oraovician fossils in upper division 

Coronado. qu artz ite 

ZOO feet Brown and red qua rtz it ic sa,,dsto.oel with conglomerate Jocall 

Mart in lim estone 

3Z·5 f eet 

Generally rather thin beds. 

Fossiliferous in ~lpper half. 

Gritty at base. Shale at top 

Troy q uartzite 

400feet 

Genera l !y pebbly cross-bedded 

ite with lenses of conglome r·ate . Sha ly rusty bed5 with worm ca ts 

at top 

Mesca l l imestone 

225 f eet 

Thin varicolored, more or· less 

dolomitic beds w ith conspicuous cherty layers 

\ 

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........ __ .?s 

0/j".s ',, 

' ', 

' ' ' ' ' ' ' ' ' 

Ransome,F:L. 

From unpublished 

data 

Tornado lime st o n e 

Martin limestone 

300± feet 

Thin dolomitic beds with some 

sandstone and shale,especially 

in upper part 

Mesca l I imestone 

300 fe et 

Hard, rather thin bedded cherty 

dolomitic limestone. · 

Weathers dark 

Dripp ing Spring quartzite 

500± f eet 

Same genera! character· as in 

Globe and Ray quadrangles 

VI 

' 

IN DEX MAP SHOWING LOCAT I:) N OF SECTI ONS M EASURED A ND RELATI ON 

OF LOCALI TIES YISITD TO PUBLISHED TOPOG RAP HI C A N D 

GEOLOGIC WORK IN ARIZONA 

Outlined n~r: angles r~presen t topographic maps. Shaded areas represent published geologic folios 

Dots ana roman numer.1ls represent iocations of colurT~nar sections 

I 

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F. 

0 

2 

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IX i 

___ --:.::::.=-JEROME REGION j 

--'/ Ransome,F.L. 

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) sOUTHERN PART . OF THE 

~ // From unpubl ished 

(:-.~~ data ~ 

SIERRA ANCHA 

Ransome,F. L. 

From unpublished 

data 

' ' " ' ' 

' ' U>o 

~/ 

""' I 

\ 

~~~~~ ~~~~---------~ \ 

Massive medium ~rained quartzitic 

sandstone.2DO :tfeet 

Hard whit e quartzitic sandstone 

with streaks of pebbles. Be ~S-6feet . Forms cliff 

ZOO feet 

M:)ssive fine-grained pink to buff 

sandstone. Forms cliff 

Laye258~;fb1es. 

Fine-grained homogeneous pinkish 

sandstone. Wea her~ <:~bby and 

forms slope. 300 feet 

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// y / / ,. HEAD.QF 

/ 

/ 

/ 

1 / //CANYON CREEK 

1 // Gilbert.G.K 

/ ·~"'"' Wheele,· Survey, / (:'' Vol. 3,pp 163-164, 

I".><, 1875 I I 

;I 

II 

,..., 

/ 

NORTHERN PART 

OF THE. 

SIERRAANCHA 

DEL5HAY 8A51N 

Ransome, FL. 

From unpublished 

data 

Mas ~i ve fine-grained red-brown 

sandstone. Beds 12 feet cr more thick. Cross- bedded at low angles. Forms cliff. 

iSOfeet 

Apparently fine-gra ined redbrown sandstone. Exposures poor 

Coarse red -brown arkosic quartzitic sandst one, with layers 

of conglomerate and af spotted 

red sha ie.J50feet 

Cocon ino s and stone 525 f eet 

Massive cross-bedded yeHow 

sandstone 

Red and purple sandstone, 

soft at top, massive -below. 

500 feet 

Redwa ll limestone? 

325 feet 

Alte r nat ing gray limestone and 

shale with some sandstone. 

Fossiliferous 

Coconino sa ndst one 500±feet 

Fine-grained th ick-bedded 

sparkling buff to wh ite sandstone with conspicuous cross· 

beddi ng 

Supai f ormation ? 

I,OOO ±feet 

Soft calca reuus shales and sandstones with scme sandy Ji 

General color bright red . 

Thick bed of gray limestone at top 

Redwa ll limestone? 

Z50feet 

Th ick-bedded white and gray 

limestone 

Th in-bedded compact limest one in lower part, becom ing sandy in upper part 

Devonian fossils. 

500 feet 

GREAT 1/NCONf'ORM!TY -+-+--l1iii'i GREAT UNCONfORMITY .f--.- 1----'~?ri GREAT~NCO,o/fORMITV--+--+-j_~ :::~~~~~~~~~~~~~~l====i~t:~~~~~-:::;~~ e~,~~;~~~~.~~~;~~ -- --~ --4c~~~~~~~';;~;:;;'~~;~:~~.;~:~~~~·~~----L--=J=~~~~~~- Conglomerat e. 3fe.et ~ '' GREAT UNCONFORMITY-+-+----'" 

Pinal schist 

Ser ci ic schist; chiefly meta- morphcsed sediments . Cut by 

granite 

P;na I schist a~d gneissic quartz- mica diorite Pinal schist a nd gran ite Pi nal sch ist 

and intr usive granitic rocks Granite Granite 

Granite 

he above section eisewhere over I ies 

vnc;onformab!y olde r· C;ombrian 

sch1st and younger pn~ -Carnbrian 

quartz ite and oonglomerate ) 

"Horn blen de rock 

and schists,, Schist 

/ 

I ' 

PROFESSIONAL PAPER 98 PLATE XXV 

X 

GRAND CANYON 

KAIBAB DIVIS ION 

Based ch iefly on worl<. 

of L.f Nob!e, 

U. 5. Geologioal Survey 

Bulletin 549, Plate IX, 1914 

Ka i ba b limestone 

4 00-600feet 

Uppe r portion,dense gray crystalline limestone, cherty near top. 

Fossil iferou'5. 

l-ower portion, ff limestone 

and calcar·eous sandstone 

Coconino sandstone 

Z50- 350feet 

Light-buff nne-grained cal- careous sandstone w ith con- spicuous cross-bedding 

Supa i. formation 

1,2 50 -1,400 feet 

Upper- portion, soft red shaly 

sandstone and red s ha le 

Lower portion, hard fine -

grained cross-bedded sand - stone, interbedded with 

red shale 

Redwa II limestone 

600-700 feet 

Alternating beds of ca lcareo us 

sandstone, thin-bedded mottled 

li-mestone, and dense blue-gray 

limestone in lower portion; pass- ing upward into dense blue-gray 

lrmestone with bedding planes 

indistinct 

Muav limestone 450c475feet 

impure thin-bedded bluish -

gray limeston e \.:.,.·ith cheracter- istic rnottling due to ienses 

of shaly material 

Bright Angel shale 

Z5 - 375feet 

Soft greer: ish micaceous sandy 

sh;:rle w1th two t hin beds of 

br-own imes~one locally 

p rese nt 1n midd le. 

Fossiliferous 

Tapeats sandstone 

0-285feet 

Brown slabby cross.-bedded 

sandstone with lenses of 

conglomerate in bosal portion 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 137 

BARNES CONGLOMERATE. 

The Barnes conglomerate lies stratigraphically above the Pioneer shale and below the 

Dripping Spring quartzite. The formation 

was first described in the Globe report and was 

named from Barnes Peak, in the northwestern 

part of the Globe quadrangle, where it is from 

10 to 15 feet thick. There is no apparent unconformity either above or below the conglomerate, although the abrupt change from a fine 

shale to a deposit of coarse pebbles is indicative 

of so extensive a modification of the conditions 

of erosion and sedimentation under which the 

shales accumulated as would seem to demand a 

notable unconformity of contemporaneous origin somewhere within the region of deposition. 

In its typical development, as near Pioneer 

Mountain or on Silver Creek, in the Ray quadrangle, the Barnes conglomerate consists of 

smooth pebbles of white quartz and hard vitreous quartzite in an arkosic matrix. The pebbles are generally 6 inches or less in diameter 

but in a few places there are some as much as 8 

inches in diameter. Although smoothly 

rounded, the pebbles are not globular but are 

flattened ellipsoids or round-edged disks. They 

are composed only of the most durable materials and doubtless passed through long and 

varied processes of attrition before they came to 

rest in the Barnes conglomerate. On the 

whole, such meager evidence as is obtainable 

appears to indicate that the conglomerate represents stream action rather than littoral or 

marine action. The formations that supplied 

t~e quartzitic material to the conglomerate, as 

w11l be shown later, are exposed north of Roosevelt, in the Sierra Ancha and the Mazatzal 

Range. 

. In .some J?laces the pebbles, which generally 

lie w1th therr flat sides roughly parallel to the 

bedding planes, are in contact and the propor-

~ion of arkosic matrix is correspondingly small; 

1n other places the matrix predominates. As 

a rule, the pebbles become larger and more 

abundant toward the south, although the gradation is probably not wholly regular. Thus 

at Barnes Peak the average diameter of the 

pebbles is 3 or 4 inches and the thickness of 

the formation from 10 to 15 feet. In the 

vicinity of El Capitan Mountain, in the Mescal 

Range, pebbles 6 inches in diameter are abundant, the average size is probably a little larger 

than at Barnes Peak, and the thiclmess of the 

formation is from 15 to 20 feet. At the north 

end of the Dripping Spring Range the conglomerate is rather variable. A small exposure about 11 miles north of Walnut Spring 

shows thin bands of pebbles associated with 

pinkish arkose and gray shale. The pebbles, 

which are chiefly white quartz and not very 

well rounded, rarely exooed 2 inches in diameter 

and not any over 3 inches were seen. About 

2 miles northwest of Walnut Spring the whole 

formation is from 10 to 12 feet thick, but the 

arkosic matrix is much more abundant than 

the pebbles, which although not uniformly distributed are, as a rule, most numerous near the 

base. The lower part of the bed thus presents 

in some places the aspect of the typical Barnes 

conglomerate, l?ut the upper · part is distinguishable from the overlying quartzite only by 

the occurrence within it of a few small and 

scattered pebbles. 

Northeast of Tam O'Shanter Peak, on the 

other hand, the conglomerate is about 40 feet 

thick and consists of chiefly smooth, rounded 

pebbles that are generally in contact with one 

another, with just enough matrix to fill the 

interstices. Some of the pebbles are as much 

as 10 inches in diameter, but most of them are 

under 6 inches. In the Tortilla Range, south 

of Kelvin, the conglomerate is about 55 feet 

thick and contains abundant characteristic 

pebbles 8 inches or less in diameter. 

The arkosic matrix of the conglomerate is 

generally similar to the material of the overlying Dripping Spring quartzite, although perhaps a little coarser. It varies in hardness, but 

as a rule all the constituents of the conglomerate are cemented by silica into a hard and durable rock in which fractures traverse pebbles 

and matrix alike. A very characteristic feature of the Barnes conglomerate is the presence in the matrix of small fragments of 

vermilion-red chert or jasper as much as an 

inch or so in diameter. 

A view of the upper part of the Barnes conglomerate as exposed on El Capitan Creek, in 

the northeastern part of the Ray quadrangle, 

is shown.in Plate XXVI, 0. 

DRIPPING SPRING QUARTZITE. 

The Dripping Spring quartzite lies conformably on the Barnes conglomerate and under the 
138 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Mescal limestoneJ Approximately the lower 

third of the formation consists of hard finegrained arkosic quartzites, which, as seen in 

natural sections, show no very definite division 

into distinct beds but do exhibit a pronounced 

striping, due to the alternation of dull-red 

and dark-gray or nearly black bands parallel 

with the planes of stratification. These bands 

as a rule are less than 1 foot thick and give a 

generally thin-bedded aspect to this portion of 

the formation, as may be seen from Plate 

XXVII B although the illustration fails to ' ' ' show the contrasting tints of the bands. About 

midway between the top and bottom of .the 

formation the striped beds are succeeded by 

fairly massive beds, as much as 6 feet thick, of 

even-grained buff . or pinkish quartzite associated with flaggy variegated red, brown, and 

gray beds and with some layers of gray and 

reddish shales suggestive of the Pioneer shale. 

In the upper part of the formation the beds 

become thin, flaggy, and rusty, with a tendency 

to grade into the Mescal limestone. 

The sand which became the Dripping Spring 

quartzite was deposited in shallow water and 

was at times exposed to the air, as may be 

seen from the ripple marks, sun cracks, and 

fossil worm casts visible on the surface of the 

beds. The deposit is tentatively regarded as 

of delta origin. It is composed throughout of 

fine n1aterial, and contains no pebbles, so far 

as known. This feature and the banding of 

its lower beds s~rve throughout the Ray quadrangle to distinguish this quartzite from the 

pebbly cross-bedded Troy quartzite, to be described later. 

Where almost vertically upturned in the 

Tortilla Range the Dripping Spring quartzite 

appears to be about 500' feet thick, but the 

presence of intrusive diabase detracts a little 

from the reliability of this measurement, as 

movements during the intrusion may have 

increased the apparent thickness. Southwest 

of Pioneer Mountain, where the whole of the 

quartzite seems to be exposed without noticeable faulting, the thickness obtained by calculation from the width of the outcrop as mapped, 

the average dip of the beds, and the general 

angle of topographic slope is between 450 and 

1 This is a redefinition of Dripping Spring quartzite as the name was 

originally used in the Globe quadrangle. The reasons for the change 

have been pui:Uished (Min. and Sci. Press, vol. 102, pp. 747-748, 1911) 

and are summarized on pages 143-144 of the present paper. 

500 feet. At Barneo; Peak, in the Globe quadrangle, the thickness was estimated at 400 feet. 

The average thickness for the Ray quadrangle is taken at 450 feet, which is probably 

under rather than above the truth. 

MESCAL LIMESTONE. 

The Mescal limestone was first recognized as 

a distinct formation in the course of mapping 

the Ray quadrangle and is named from the 

Mescal Mountains, where it is well exposed. 

Stratigraphically it is limited below by the 

Dripping Spring quartzite and above by the 

Troy quartzite. Some fragments of this formation, most of them intimately associated 

with intrusive diabase, occur in the Globe quadrangle, but when the report on that area was 

prepared these masses of strata were supposed 

to be somewhat metamorphosed portions of the 

thin Devonian beds in the lower part of the 

"Globe limestone." 

Iri the Ray quadrangle also the Mescal limestone and the diabase are closely associated. 

Lying between the two heavy quartzitic formations · the thin-bedded dolomitic limestone ' proved an easy path for the invading diabase 

magma and retains little of its former continuity. In the development of the topography 

the diabase tends to wear down into swales and 

hollows, and an extended view over one of 

these depressions shows the generally olivetinted surface characteristic of diabase areas, 

varied by blotches of white that represent 

included blocks of the Mescal limestone, some 

of which are nearly a quarter of a square mile 

in area. Other portions of the formation rest 

in their original position on the Dripping Spring 

quartzite, and the diabase lies in igneous contact above them. Still others crop out along 

the bases of cliffs formed by the Troy quartzite 

and lie above the intruded diabase. Rarely 

the limestone lies unbroken between the two 

q@rl~~- . . . 

The Mescal limestone Is composed of thin 

beds that have a varied range of color, but are 

persistently che~ty, the siliceous segregati~ns 

as a rule forming irregular layers parallel With 

the bedding planes. On weathered surfaces 

these layers stand out in relief and give to the 

limestone the rough, gnarled banding that is 

its most characteristic feature. The usual appearance of the Mescal limestone on outcrop-
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XXVI 

A. BARNES CONGLOMERATE AT SOUTH END OF B. MESCAL LIMESTONE ON EL CAPITAN CREEK, 

PINAL RANGE, GLOBE QUADRANGLE, ARIZ. MESCAL RANGE, RAY QUADRANGLE, ARIZ., 

SHOWING EFFECT OF WEATHERING. 

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

A. CROSS-BEDDED PEBBLY TROY QUARTZITE} DRIPPING SPRING RANGE. 

B. BANDED DRIPPING SPRING QUARTZITE, MESCAL RANGE, 1 MILE SOUTH 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 

general hue of the formation is gray or white, 

but some beds are yellow, buff, brown, or rusty. 

In some localities the rough, gnarled strata are 

accompanied by others containing thin regular 

buff and gray layers whose differences in chemical composition in conjunction with the dissolving action of atmospheric water gives rise 

to such natural ornamentation as is illustrated 

in Plate XXVI, B. 

Between the limestone and the overlying 

Troy quartzite is a layer of decomposed vesicular basalt whose maximum observed thickness is 100 feet. Although the basalt is in 

places much thinner than this, the flow was 

apparently coextensive with the Mescal limestone throughout the Ray· and Globe quadrangles. Where the basalt is in contact with 

the later intrusive diabase distinction between the two is difficult in the absence of 

good exposures, and in the earlier work in the 

Globe quadrangle the altered vesicular basalt 

was supposed to be merely a contact modification of the diabase. 

A section of the Mescal limestone with the 

overlying basalt flow, as exposed on the east 

side of El Capitan Canyon, is given below. 

The thicknesses stated are approximate. 

Section of the Mescal b~mestone. 

Troy quartzite. Feet. 

Vesicular basalt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 

4. Striped buff and gray dolomitic limestone weathering sharp channels and ridges, as illustrated in 

Plate XXVI, B..... . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

3. Very rough cherry dolomitic limestone with no 

distinct division into beds. Weathers with 

gnarly dark rusty-brown surface................ . 30 

2. Gnarled, knotty cherty limestone, mostly dolomitic, in beds as much as 2 feet thick. Some 

beds light gray and some dark brown. Shaly 

partings.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 

1. Thin impure shaly limestone, with perhaps some 

dolomite. Splits into thin leaves. Mostly light 

graY.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

Dripping Spring quartzite. 295 

The analysis of a sample from division 2 of 

the foregoing section is as follows: 

Partial chemical analysis of Mescal limestone. 

[George Steiger, analyst.] 

Si02••• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 29. 93 

Al20 3 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 42 

CaO........ . . . . . . . . . . . . . . . . . . . . . . . . . 21. 90 

MgO ................................. 14.90 

30830°--17----10 

This rock weathers brown but on fresh fracture is almost white. The molecular ratio of 

lime and magnesia is nearly that of dolomite, 

but as the beds are not all of the same character the foregoing f:malysis does not represent 

accurately the .composition of the whole formation. 

In the narrow gorge just west of Hackberry 

Spring, in the southwestern part of the Ray 

quadrangle, the Mescal limestone stands almost 

vertical and has a thickness of 225 feet. In 

the section given above the total thickness 

is stated as 220 feet, exclusive of the vesicular 

basalt. This, how•3Ver, is an estimate based 

on barometric readings corrected for a dip of 

about 25°. The average thickness of the 

formation as mapped in the Ray quadrangle 

and including the basalt flow may be taken as 

about 250 feet. 

TROY QUARTZITE. 

The Troy quartzite lies conformably above 

the Mescal limestone and below the Martin 

limestone. Prior to the detailed mapping of 

the Ray quadrangle this quartzite had not been 

recognized as a formation distinct from the 

lower or Dripping Spring quartzite, for in the 

Globe quadrangle there are no sections that 

show the two quartzites separated by the 

intervening Mescal limestones, and such brief 

papers on the geology of the Ray quadrangle 

as have appeared ::~ince the Globe report was 

published have dealt only with the immediate 

surroundings of the copper deposits at Ray, 

where the stratigrnphic relations of the sedimentary rocks are less clearly displayed than 

elsewhere in the quadrangle. The name of the 

formation is derived from Troy Mountain, in 

the Dripping Spring Range. · 

· The Troy quartzite is one of the most prominent and widely exposed formations in the Ray 

quadrangle. The beds differ greatly in thickness, ranging from thin flaggy or shaly layers 

to cross-bedded pebbly beds from 25 to 50 

feet thick. On the whole the thicker beds are 

characteristic of the lower and n1iddle portions 

of the formation. The upper part is invariably composed of thin, generally yellowish or 

rusty worm-marked shaly quartzite indicative 

of a change in sedimentation preparatory to 

the deposition of the Devonian limestone. 

The most characteristic material of these 
140 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

upper beds consists of layers, an inch or two 

thick, of fine-grained, unevenly colored brown, 

pink, and green quartzite separated by films 

of olive-gray shale whose cleavage surfaces 

are ridged and knotted with numerous worm 

casts. The quartzite layers appear almost 

dolomitic in color and texture, but the microscope shows them to consist chiefly of closely 

fitting quartz grains with specks of flocculent 

limonite and little nests ·of a green chloritic 

mica. The most noteworthy features of the 

thicker beds are their generally pebbly character, which is a useful means of distinguishing 

isolated exposures of the Troy quartzite from 

the pebble-free Dripping Spring quartzite, and 

their conspicuous cross-bedding. These characteristics are illustrated in Plate XXVII, A. 

While the Dripping Spring quartzite is nearly 

all arkosic the Troy quartzite shows little or 

no feldspar. 

A not quite complete section of the Troy 

quartzite as exposed in nearly horizontal attitude 1! miles southeast of Tam O'Shanter 

Peak, in the Dripping Spring Range, is given 

below, with approximate thicknesses. 

Section of Troy quartzite. I, 

11. Yellowish, rusty, thin-bedded quartzites with 

olive-gray shale partings roughened by worm 

casts; at least .... _ ..... __ ............ ______ _ 

10. Fine-grained quartzite with very regular laminations from 2 to 6 inches thick ........... _. 

9. Rather thin beds of white fine-pebbly quartzite 

8. A single bed of massive cross-bedded finepebbly white quartzite, with layers of small 

quartz pebbles ev~ few feet. Forms a cliff. __ . _ . _ . ____ . ___ ~ ____ .......... ____ . __ _ 

Sheet of porphyry, 25 feet. 

7. Partly concealed; apparently rather thin bedded gray pebbly quartzite .... _ ......... ___ . 

6. Two beds of cross-bedded coarse quartzite or 

grit, with scattered pebbles of white quartz 

as much as 6 inches in diameter. Forms a 

scarp ............. ________ ...... _________ . 

5. Conspicuously cross-bedded gray quartzite, 

with many layers of small quartz pebbles. 

No distinct separation into beds, but obscure 

laminations average about 1 foot in thickness. Forms a stepped slope. Microscope 

shows typical quartzite texture with enlarged interlocking quartz grains .. _____ .... 

4. Conglomerate with fairly well rounded pebbles, mostly of white quartz, as much as 4 

inches in diameter, in an abundant crossbedded matrix of coarSe quartzite ......... . 

3. Soil-covered slope, apparently underlain by a 

yellowish shale or fine-grained quartzite. " .. 

Feet. 

50 

It 

50 

50 

35 

15 

75 

6 

25 

2. Cross-bedded pebbly quartzite in beds 4 to 10 

feet thick. Pebbles quartz; rarely over 2 

inches in diameter; in places scattered and 

in places concentrated in irregular lenticular 

layers. Weathers gray or rusty. Forms a 

Feet. 

stepped slope ..................... __ ...... 25 

1. Bed of irregularly banded gray quartzitic breccia grading up into cross-bedded coarse grit 

or conglomerate with quartz pebbles. Breccia in lower part of bed contains angular 

fragments of white quartz 6 inches or less in 

diameter. Forms a cliff............ . . . . . . . . 30 

362! 

Bed No. 1 is the bottom of the Troy quartzite. Below it is the vesicular basalt at the 

top of the Mescal limestone. 

Although much of the Troy quartzite is 

light gray or white on fresh fracture, the 

weathered exposures are generally buff, brown, 

rusty, or maroon. In the canyon northwest 

of Tam O'Shanter Peak, where the quartzite 

is finely exposed, the general tint is reddish 

brown, but the different parts of the formation vary in color from white or pale buff to 

dull dark red. 

Determination of the exact thickness of the 

Troy quartzite is difficult, owing to the fact 

that few of the many fault blocks show a full 

section of the formation or give opportunity 

for detailed measurements. The section recorded above gives a total thickness of about 

362! feet but probably does not include all 

the upper beds. In the gorge west of Hackberry Spring a measurement across the edges 

of the nearly vertical beds gave 300 feet, but 

here also there are beds missing from the top 

of the formation. A little less than 2 miles 

northwest of Tam O'Shanter Peak the formation, here nearly horizontal, is exposed in full 

section between the Mescal dolmr.ite and the 

Devonian limestone. The mapping here indicates a thickness of a little more than 350 feet. 

On Troy and Scott mountains the quartzite as 

mapped appears to be unduly thick, the distribution on Scott Mountain calling for a 

thickness of about 1,000 feet. This is clearly 

in excess of any possible real increase in the 

formation and probably is to be accounted 

for by faulting or flexing that is not distinctly 

shown at the surface. From all available 

information the average thickness of the 

formation is estimated to pe about 400 feet. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XXVIII 

A . TYPICAL EXPOSURE OF THE CHERTY 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 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 THEIR CORRELATION. 141 

The Troy quartzite, with its abundant 

pebbly layers and conspicuous cross-bedding, 

is suggestive of fluviatile or deltaic deposition. 

The upper part of this formation, however, 

grades into the undoubtedly marine Devonian 

beds. 

MARTIN LIMESTONE. 

The Martin limestone occupies conformably 

the stratigraphic interval between the underlying Troy quartzite and the overlying Tornado 

limestone and, with the possible exception of 

some of its unfossiliferous lower beds, is of 

Devonian age. The beds here separated as 

the Martin limestone were in the Globe quadrangle mapped with the overlying Carboniferous (Tornado) limestone under the name 

"Globe limestone." 

As a whole the Martin limestone is a comparatively thin bedded formation, which weathers in to slopes broken here and there by low 

scarps marking the outcrop of some bed a 

little harder or thicker than the rest. A typical natural section of the formation is shown in 

Plate XXIX, A. Distant views of such slopes 

show that the formation is divisible on the 

basis of color into two nearly equal parts. 

The prevailing hue of the lower division is 

light yellowish gray; the upper division, less 

uniform in tint, displays alternations of 

deeper yellow and darker gray. Detailed examination proves the lower division to consist mainly of very compact, hard, gray limestone in beds rarely more than 2 feet thick, 

with, at the base, a bed of impure yellow limestone containing abundant grains of quartz. 

This lowest bed, which in places is cross-bedded 

and contains so much detrital material that it 

might be classed as a calcareous grit, weathers 

to a rough sandy surface, but the overlying 

. gray beds are characterized by solution surfaces that although uneven in general are 

smooth in detail. A characteristic feature of 

these compact lower limestones is the presence of little spherical, oval, or irregular concretions of dark chert, which as a rule are 

about the size of peas. No identifiable fossils 

have been found in this lower division of the 

Martin limestone, although it contains obscure 

traces of organic life. 

About midway in the section is a bed, about 

15 .feet thick, of rusty-yellow impure sandy 

limestone showing flaggy lamination. Above 

this are dark-gray and yellowish limestones in 

beds of different thicknesses, with shaly partings. These strata are generally fossiliferous, 

some of the shaly partings particularly being 

orowded with Atrypa reticularis and other small 

Devonian brachiopods. Some very dark beds 

in this upper division of the formation are 

marked with an obscure mottling suggestive of 

the former presence of some of the corals which 

are abundant in oertain beds of the Martin 

limestone at Bisbee but which in the Ray quadrangle have been less perfeotly preserved. The 

top bed of the Devonian is a yellow calcareous 

shale which breaks up on exposure into minute 

thin flakes and which consequently has no 

prominent outcrops. The yellow color is characteristic of all natural exposures, although 

before weathering the shale is gray. Being 

overlain by the massive cliff-making Carboniferous limestone, the bed of shale is in many 

places concealed by talus, and its thickness was 

not exactly determined. It.may be from 15 to 

20 feet thick, but its base is not very olearly 

defined, for layers of similar shale ooour between 

some of the limestone beds in the upper part of 

the formation. 

The Devonian limestone is generally magnesian and does not effervesce freely in cold dilute 

acid. An analysis of a typical specimen from 

the lower division of the formation is as follows: 

Partial chemical analys1s of Devonian limestone. 

[R. C. Wells, analyst.] 

Si02 ••••••• •• • • • • • • • • • • • • • • • • • • • • • • • • 3. 11 

Al20 3 ••••• ••••••••••••••••••••••••••• • 33 

Fe20 3 and FeO.......... . . . . . . . . . . . . . 1. 22 

CaO ................................. 31.65 

MgO ........ , ...................... 18.65 

Measurements and estimates of the thickness of the Martin lintestone in different parts 

of the quadrangle range from 300 to 350 feet. 

The average thickness is considered to be 

325 feet. 

In contrast with the older formations, which 

have yielded no determinable organio remains, 

the upper division of the Martin limestone contains fossils at many horizons from the top of 

the rusty bed at its base to the lower layers of 

the yellow shale. In all 18 lots of fossils were 

collected and were referred to E. M. Kindle, 
142 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

then of the United States Geologioal Survey, 

who lists the following species: 

Zaphrentis sp. undet. 

Productella hallana. 

Stropheodonta arcuata. 

Stropheodonta demissa. 

Stropheodonta varistriata. 

Stropheodonta sp. 

Leptostrophia cf. L. intelistrialis. 

Strophonella cf. S. ampla. 

Schuchertella chemungensis. 

Schizpphoria striatula. 

Atrypa reticularis. 

Atrypa hystrix occidentalis. 

Atrypa spinosa. 

Camarotrechia sp. 

Pugnax pugnus. 

Spirifer orestes. 

Spirifer hungerfordi. 

Cyrtia cyrtiniformis. 

Schizodus sp. 

Paracyclas cf. P. elliptica. 

Euomphalus cyclostomus? 

Euomphalus sp. 

Bellerophon sp. undet. 

Dr. Kindle remarks with reference to this 

fauna: 

On the ground of its close relationship to an Upper Devonian fauna of Iowa and its stratigraphic relations to the 

Carboniferous fauna of the Arizona section, I would place 

the fauna of the Martin limestone and its equivalent, the 

Devonian fauna of the Ray q}ladrangle, in the Upper 

Devonian. It is of course possible that the time range of 

this fauna in Arizona may include Middle as well as Upper 

Devonian, but that it includes the Upper Devonian in any 

event seems well established by the available evidence. 

As the Devonian portion of the "Globe limestone" in the Globe quadrangle is continuous 

and identical with what is now designated the 

Martin limestone, fossils collected from it 

should be included in the Martin fauna. For 

convenience therefore the list of determinations made by H. S. Williams 1 on the older 

collections, with slight changes by Dr. Kindle, 

to bring it into accord with present nomenclature, is given below. 

Of. sponge. 

Of. Rhodocrinllil, crinoid stems and plates. 

Atrypa reticularis Linne. 

Productella hallana Walcott. 

Stropheodonta calvini Miller. 

Cyrtia cyrtiniformis (Hall and Whitfield). 

Spirifer hungerfordi Hall. 

Spirifer orestes Hall and Whitfield. 

Spirifer whitneyi Hall. 

Reticularia fimbriata (Conrad). 

Cyrtina hamiltonensis Ha.ll. 

Martinia subumbona (Hall); cf. Spirifer infima 

Whidborne. 

Pugnax pugnus (Martin). 

Schuchertella chemungensis (Conrad) var. 

Dielasma cf. D. calvini (Hall and Whitfield). 

1 Ransome, F. L., U.S. Geol. Survey Prof. Paper 12, pp. 40-42, 1903. 

TORNADO LIMESTONE. 

The Tornado limestone, named from Tornado Peak, in the southeastern part of the 

Ray quadrangle, where it is extensively 

exposed, overlies with apparent conformity 

the Martin limestone and is equivalent to the 

Carboniferous portion of the " Globe limestone" as mapped in the Gbbe quadrangle. 

In places its upper limit is a surface of erosion 

upon which in general rests the Quaternary 

Gila conglomerate, although in the southeastern part of the Ray quadrangle there is 

an intervening andesitic formation, probably 

of Mesozoic age. 

Th~ Tornado limestone is generally light 

lead-gray in color and is divisible with respect 

to thickness and character of bedding into at 

least three members. The basal division, 

directly overlying the Devonian, is about 75 

feet thick and forms the lower part of the 

scarp that is so prevalent a feature of the 

Carboniferous outcrops in central and southern 

Arizona. Under the action of erosion this 

division behaves as a single massive bed, but 

in reality it is made up of alternating dark 

and light gray layers, a foot or two thick 

which in cliff faces give this member a banded 

appearance, as may be seen in Plate XXIX, A. 

(p. 141). This banded division with a few 

transitional beds at its top is succeeded by a 

very massive member, fully 100 feet thick, 

within which, as exposed in cliff faces, there 

is as a rule little more than a suggestion 

of divisional bedding planes. This massive 

member (Pl. XXIX, A.) is of lighter and 

more uniform tint than the basal member. 

The two together constitute the principal 

cliff-forming part of the Carboniferous limestone. The third division consists of beds 

generally thinner than those in the other 

two divisions but not separable from them by 

any marked lithologic distinction. 

The Tornado limestone consists essentially 

of calcium carbonate and effervesces freely 

in dilute acid. An analysis of a typical sample 

is as follows: 

Partial chemical analysis of Tornado limestone. 

[W. T. Schaller, analyst.] 

Si02•••••••••••• • • • • • • • • • • • • • • • • • • • • • 1. 36 

Al20 3 •••••••••••••••••••••••••••••••• • 22 

CaO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54. 91 

MgO............ . . . . . . . . . . . . . . . . . . . . . . 21 

Thin layers of calcareous shale separate 

some of the beds; but these are a very subordinate part of the formation. I 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 143 

Although nearly all the Carboniferous limestone contains fossil remains, there are few 

localities where full and satisfactory collections 

can be made. The beds of the two lower 

divisions carry abundant fragments of crinoid 

stems and less numerous rugose corals with 

long-winged spirifers and Rhipidomella. These 

appear in silicified form on weathered surfaces 

of the rock, but they can not readily be separated from their matrix. In the upper 

division appear different species of Productus 

and Spirifer, Derbya crassa, Oomposita subtilita, 

and Fusulina. 

Of seven collections made at as many different localities in the Ray quadrangle, four, 

according to George H. Girty, of the Geological 

Survey, consist of Mississippian forms, and 

three of Pennsylvanian forms. His determinations of these fossils are as follows: 

Mississippian fauna. 

Syringopora aculeata Girty? 

Menophyllum sp. 

Amplexus? sp. 

Rhipidomella aff. R. oweni Hall and Clarke. 

Rhipidomella dubia Hall? 

Leptrena analoga Phillips. 

Schuchertella inflata White and Whitfield? 

Chonetes sp. 

A vonia arcuata Hall? 

Camarotrechia metallica White. 

Dielasma burlingtonense White. 

Spirifer centronatus Winchell. 

Brachythyris peculiaris Shumard. 

Spiriferina solidirostris White. 

Syringothyris sp. 

Composita humilis Girty? 

Cliothyridina sp. 

Pennsylvanian fauna. 

Fusulina sp. 

Derbya crassa Meek and Hayden. 

Productus semireticulatus Martin. 

Productus cora D'Orbigny. 

Pustula semipunctata Stevens. 

Spirifer cameratus Morton. 

Spirifer boonensis Swallow? 

Composita subtilita Hall. 

Myalina subquadrata Shumard. 

According to Mr. Girty, the older of these two 

faunas is early Mississippian and the other is 

early Pennsylvanian. He notes that the conditions exhibited in the Ray quadrangle are 

apparently similar to those at Bisbee, where a 

limestone of probable early Pennsylvanian age 

(theN aco) rests directly on a limestone of early 

Mississippian age (the Escabrosa). The Mississippian in th~ Ray quadrangle, therefore, corresponds to the Escabrosa limestone at Bisbee, 

and the Pennsylvanian limestone near Ray to 

the lower part of the Naco limestone. 

In the Bisbee quadrangle the distinction 

between the Mississippian and Pennsylvanian 

limestones proved practicable, although the 

plane of demarcation is not definite. In the 

Ray quadrangle a similar distinction might 

possibly be made., but no satisfactory basis for 

it appeared in the course of the field work, and 

it is doubtful whether its accomplishment 

would be worth the additional labor involved. 

The cliff-making lower members of the Tornado 

limestone are certainly Mississippian, and 

probably a considerable part of the upper 

member also belongs to that epoch. 

The original thickness of the Tornado limestone is unknown, for the formation was extensively eroded before the eruption of the 

andesitic lavas and before the deposition of 

the Gila COJ?.glomerate. In the vicinity of 

Tornado Peak and along the east flank of the 

Tortilla Range the limestone at present must 

be £ully 1,000 feet thick, and it may at one 

time greatly have exceeded this thickness. 

NOMENCLATURE. 

The foregoing descriptions h~ve been written 

with special reference to the formations as they 

are displayed in the Ray quadrangle, but they 

apply with,ou.t essential change to the adjoining 

Globe quadrangle. When that area was studied, about 11 years ago, little was known of the 

stratigraphy of ~h}s part of Arizona and it 

appeared impracticable, in so intricately faulted 

a district, to rna p the sedimentary rocks in as 

great detail as has since proved possible in the 

Ray qw:tdrangle. In the Glob~ report the 

Scanlan conglomerate, Pioneer shale, Barnes 

conglomerate, and Dripping Spring q~artzite, 

while distinguished in certain geologic sections, 

were mapp(3d together as the "Apache group" 

and the Devonian and Carboniferous limestone 

were mapped as the "Globe limestone." As 

none of the numerous small fault blocks into 

which the Globe district is divided afforded a 

complete geologic section, and as no quartzite 

was foTitnd overlying limestone, all the quartzite was supposed to belong to one formation 

(the Dripping Spring quartzite), and all the 

limestone was supposed to belong to the 

Devonian and Carboniferous "Globe lime-
144 SHORTER CONTRIBUT'IONS TO GENERAL GEOLOGY, 1916. 

stone." The "Globe limestone," as mapped, 

therefore included a little Mescal limestone, 

and the Troy quartzite was not distinguished 

from the Dripping Spring quartzite. Had the 

existence of the Mescal limestone and Troy 

quartzite been known when the Globe report 

was written, these two formations· would 

probably have been included in the definition 

of the Apache group. 

As at present constituted, this group consists 

of the following formations, named in ascending 

order: Scanlan conglomerate, Pioneer shale, 

Barnes conglomerate, Dripping Spring quartzite, Mescal limestone, and Troy quartzite. All 

are apparently conformable and are provisionally assigned to the Cambrian. 

SANTA CATALINA GEOLOGIC SECTION. 

As the Santa Catalina Range, northeast of 

Tucson, is being carefully studied by Prof. C. 

F. Tolman, jr., ~or the United States Geological Survey, and as my own observations were 

confined to an excursion of only six days' duration, under his guidance, the treatment accorded in this paper to the geology is necessarily brief and general. 

The central feature of the range, as worked 

out by Mr. Tohnan, is a great post-Carboniferous intrusive mass of siliceous muscovite granite modified to a gneissic rock near its margins, 

surrounded by a zone of intense contact metamorphism in which rocks of widely different 

kinds have been conspicuously affected. The 

oldest rock cut by this granite is a coarse, porphyritic biotite granite· which, apparently as 

a result of the later granitic intrusion, grades 

into augen gneiss, and locally this rock in tum 

has been transformed into a thinly fissile schist. 

Resting upon a worn and weathered surface 

of the pre-Cambrian granite, as may be well 

seen on the east side of Oracle Ridge, north of 

Apache, is the Scanlan conglomerate, 10 to 12 

feet thick, composed of imperfectly rounded 

pebbles of white quartz in a much silicified 

matrix. The conglomerate grades upward 

through several feet of very hard white quartzite into fine-grained sericite schists-the locally 

metamorphosed Pioneer shale. In some localities in the Santa Catalina Range the crystalline 

texture is so well developed that these altered 

shales might easily be mistaken for the preCambrian Pinal schist. It may be noted in 

this connection that the Pioneer shale has been 

metamorphosed to crystalline schist by the intrusion of granodiorite at Troy, in the Ray 

quadrangle, also. The metamorphism there, 

however, is on a much smaller scale than in 

the Santa Cata~a Range. Overlying the 

schist in the vicinity of Apache is the Barnes 

conglomerate, showing its well-rounded ellipsoidal pebbles. Its thickness here is about 12 

feet. Although it is more silicified than the 

typical conglomerate of the Ray quadrangle, 

there can be little doubt of its stratigraphic 

identity. Southeast of Apache, on the east 

slope of the range, the Barnes conglomerate is 

overlain by a quartzite which is correlated with 

the Dripping Spring quartzite, although its 

character has been modified by the prevalent 

metamorphism. Stratigraphically above the 

quartzite is a formation that is probably the 

Mescal limestone. In a few places the limestone shows some of the cherty bands so characteristic of this formation near Ray, but as a 

rule the beds are much metamorphosed. Some 

have been squeezed and kneaded so that the 

chert layers have been dr~wn out into thin curly 

laminre; others have been changed to crystal .. 

line schist or to fine-grained garnet-epidote 

rock. The vesicular basalt that overlies the 

Mescal limestone in the Ray quadrangle was 

not recognized in the brief examination made 

of the Catalina Range. 

Above the Mescal limestone is a pebbly 

quartzite with bands of conglomerate and 

with thin, shaly worm-marked beds near the 

top; in all probability this is the Troy quartzite. 

The quartzite is overlain by generally rather 

thin bedded Devonian limestones, from which 

Mr. Tolman has collected f:ossils, followed in 

ascending stratigraphic succession by the 

thicker-bedded gray Carboniferous limestone. 

Finally, these formations are unconformably 

overlain by a thick series of red shales, containing some impure sandy limestone, with a heavy 

limestone conglomerate at the base. These 

beds may possibly belong to the Manzano 

group/ but Mr. Tolman has not yet found any 

fossils in them. 

In the short time devoted to the Santa Catalina Range no attempt was made to measlU'e 

the thicknesses of the different formations. 

Disturbance and metamorphism render this a 

difficult task, but Mr. Tolman will doubtless 

attempt it before the completion of his work. 

The general impression obtained, however, was 

1 Lee, W. T., and Girty, G. H., The Manzano group of the Rio Grande 

valley, N Mex.: U.S. Geol. Survey Bull. 389, 1909. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XXX 

A. TYPICAL EXPOSURE THREE-FOURTHS OF A MILE NORTHWEST OF MILITARY HILL, 

TOMBSTONE DISTRICT. 

B. TYPICAL EXPOSURE ON ESCABROSA RIDGE, WEST OF BISBEE. 

ABRIGO LIMESTONE IN THE MULE MOUNTAINS, ARIZ. 

SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 145 

that the formations making up the Santa 

Catalina section do not differ greatly in their 

respective thicknesses from those at Ray. 

BISBEE GEOLOGIC SECTION. 

From Apache, in the Santa Catalina Mountains, to Tombstone the distance is about 70 

miles, and from Tombstone to Bisbee about 20 

miles. Between the Santa Catalina Range 

and the north end of the Mule Mountains, 

·where Tombstone is situated, lies a country 

about which little geologic information is available. The principal monntain range in this 

interval is the Whetstone, southwest of Benson. These mountains were visited over 10 

years ago by Dumble,t who reports over 1,300 

feet of limestones and sandstones referable to 

the Carboniferous and 5,000 feet of sands and 

clays that he assigned to the Triassic. The 

range evidently is of much stratigraphic interest, especially in view of the fact that, as 

will presently be shown, the sections at Tombstone and Bisbee are considerably different 

from those of Ray and the Santa Catalina 

Range. Some carefully measured and described sections from the Whetstone Mountains 

would constitute a valuable contribution to the 

stratigraphy of Arizona, and as these mountains 

are readily accessible it is to be hoped that some 

geologist will before long find opportunity to 

study them. 

A strictly geographic order of treatment 

would necessitate consideration of the section 

at Tombstone before that at Bisbee; but the 

latter was the first to be studied in detail and 

as it constitutes the type to which the Tombstone section conforms, it may conveniently be 

given priority of description here. 2 

Resting unconformably on the Pinal schist 

at Bisbee is the Bolsa quartzite, 430 feet thick, 

with a bed of conglomerate from 6 inches to a 

foot in thickness at its base. Most of the 

pebbles of this basal conglomerate are composed of white quartz and are less than 3 inches 

in diameter. The conglomerate is overlain, 

with no definite plane of division, by hard 

cross-bedded pebbly grits, the individual beds 

of which are from 10 to 20 feet thick, and above 

these lie thinner, finer-grained quartzites. The 

general color of the formation is rusty brown. 

1 Dumble, E. T., Notes on the geology of southeastern Arizona: Am. 

Inst. Min. Eng. Trans., vol. 31, pp. 696-715, 1902. 

2 For the original detailed descriptions of the formations at Bisbee see 

Ransome, F. L., The geology and ore deposits of the Bisbee quadrangle 

Ariz.: U.S. Geol. Survey Prof. Paper 21, pp. 28-56, 1904. 

Conformably overlying the quartzite is the 

Abrigo limestone, 770 feet thick. This formation consists mainly of rather thin bedded limestones, in part sandy and dolomitic, with some 

shale. A laminated structure, due to the alternation of layers of gray limestone, generally 2 or 

3 inches thick, with still thinner sheets of chert, 

is a conspicuous feature of the formation. 

These chert bands, as may be seen from Plate 

XXX, B, are prominent on weathered surfaces, and the lithologic resemblance of the 

Abrigo to the Mescal limestone of the Ray 

quadrangle (see Pl. XXVIII, p. 140) is exceedingly close. The beds of the Abrigo are generally from 1 to 2 feet in thickness. Their prevailing color, as seen in large expostires, is dark 

greenish yellow. 

In the typical Mount Martin section, near 

Bisbee, the Bolsa quartzite is immediately 

overlain by about 40 feet of thin-bedded, very 

cherty limestones, which break up on weathering into thin rusty plates. Above these are a 

few beds of gray limestone 2 feet in maximum 

thickness, alternating with fissile yellowish calcareous shales and with laminated cherty beds, 

such as have just been described. The upper 

100 feet of the formation is made up of rather 

soft, sandy thin-bedded gray limestone, w~th 

one bed of harder gray limestone 6 feet thiCk 

about 40 feet from the top. The upper limit of 

the Abrigo formation is de:fi!ned in the Mount 

Martin section by a bed of pure white quartzite 

about 8 feet in thickness. This quartzite is a 

persistent stratum and is found immediately 

underlying the Martin limestone, which carries 

Devonian fossils. Its thickness, however, is 

variable, and in places it grades downward i1_1to 

the upper sandy limestones of the Abr1go 

formation. 

Analyses of two specimens of the Abrigo 

limestone are given below: 

Partial chemical analyses of Abrigo limestone. 

[W. F. Hillebrand, analyst .] 

1 2 

Si02 ••••••••••••••••• • •••••• • • • • • • 

t:~g _ :_ ~- -~ -:-:-:- ~: :: : :: : : :: :: ::: : : : : : } MgO ............................. . CaO ............................ . . 

11. 80 a 2.15 

1.08 

. 48 

45.86 

a Includes Ti02 and P20o if present. b Calculated as Fe203. 

12.53 

a 1. 04 

1.26 

17.41 

27.28 
146 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

These analyses show that the different beds where no detritus conceals the relation of the 

vary considerably in the ratio of lime to two formations, there may be an intermediate 

magnesia. zone 10 to 20 feet in thickness which contains 

The oldest marine fossils in this region are no characteristic fossils and which it is imposfound in the Abrigo formation and include sible to assign with confidence, on purely lithotrilobites, linguloid brachiopods, pteropods, logic grounds, either to the Martin or Escaand other early forms. The fossils collected brosa limestones. 

from this formation were submitted to Dr. The beds of the Martin limestone are usually 

Charles D. Walcott, who reported that they are less than 4 feet in thickness. They are thicker, 

Middle Cambrian. on the whole, than those of the underlying 

In the Mount Martin section the Martin Abrigo lime.stone, but thinner than those of 

limestone, carrying a Devonian fauna, overlies the overlying Escabrosa limestone. 

the Abrigo in apparent conformity. Its aver- Chemically, the typical dark limestone of 

age thickness at Bisbee is about 325 feet. the Martin formation is a fairly pure calcium 

The beds most characteristic of the Martin for- carbonate, containing a little silica but pracmation are dark-gray hard, compact limestones tically no magnesia. 

which are generally well provided with fossils. The following species from the Martin limeSmall brachiopods of rounded outline (Atrypa stone, collected in the course of the study of 

reticularis and Spirifer hungerfordi) are par- the Bisbee quadrangle in 1902, were identified 

ticularly abundant in some of the beds and by Prof. H. S. Williams: 

give to the weathered surfaces of the lime- Acervularia davidsoni (Milne-Edwards and Halme). 

stone a nodular appearance which in the Bis- Pachyphyllum woodmani (White). 

bee quadrangle is peculiar to the Martin for- Cladopora prolifica (Hall a.nd Whitfield). 

mation. A few of the beds are rich in corals, Stromatopora erratica (Hall). 

some of which weather out as distinct and in Cyathophyllum crespitosum (Goldfuss). 

Atrypa reticularis (Linne). places well-silicified fossils, while others pro- Cyrtia cyrtiniformis (Hall and Whitfield). 

duce rather ill-defined white dendritic blotches Dlelasma calvini (Hall and Whitfield). 

in the dark limestone. Schizophoria striatula (Schlotheim). 

Associated with the preponderant dark lime- Productella speciosa Hall. 

stones here and there are beds of lighter hue Delthyris consobrina (D'Orbigny). Spirifer cf. S. jeremejevi (Tschernyschew). and some calcareous shales of a decided pink- Spirifer hungerfordi Hall. 

ish tint. These shales, whjch flake and crum- Spirifer orestes Hall and Whitfield. 

ble on exposure, are well exposed in the saddle Spirifer cf. S. euryteines Owen (small specimen). 

just northeast of Mount Martin, where they Spirifer wliitneyi Hall. 

carry abundant characteristic Devonian fos- Stropheodonta demissa (Conrad). Stropheodonta (fragilis) perplana (Hall). sils. They occur also in several of the other Strophonella crelata Hall. 

areas of the Martin limestone, particularly on 

the southwest slopes of Escabrosa Ridge, but The following specimens were too imperfect 

owing to their softness they are generally in- for specific determination: 

conspicuous except where they are revealed by Coral, several species. 

prospecting pits and tunnels. They belong in Crinoid stem. 

Bryozoa. the lower half of the formation. Terebratula? (small). 

The upper limit of the Martm limestone is Minute brachiopod (?). 

not everywhere sharply defined. In general _it Loxonema. 

corresponds to the decided change from the Platyceras. 

dark compact limestones characteristic of this Pleurotomaria. 

Bellerophon. formation to the nearly white granular lime- Leperditia. 

~~;:~t:~z:e ~helai=~~b ~:in~~;;!~~~. w;~! Mr. Williams concluded that the fauna of the 

Martin limestone is Meso-Devonian, although actual plane of division; however, is rarely visi- h he regarded it as having close affinities wit 

ble, owing to the tendency of the Escabrosa the Neo-Devonian fauna of New York.l 

limestone to form cliffs and the consequent accumulation of talus over the contact. Even 1 Seeextendednotein u.s. Geol. Survey Prof. Paper21,pp. 35-42,1904. 
SOME PALEOZOIC SECT'IONS IN ARIZONA AND THEIR CORRELATION. 147 

Overlying the Martin limestone at Bisbee is 

the Escabrosa limestone, made up generally of 

rather thick-bedded, nearly white to dark 

gray granular limestones, which on close examination are seen to be made up very largely of 

fragments of crinoid stems. . Near the base the 

individual beds are commonly 10 or 15 feet in 

thickness, but above the first 100 feet thicknesses of 1 to 5 feet are the rule, though there 

are a few more massive beds. The formation 

as a whole is a pure nonmagnesian limestone, 

containing practically no arenaceous sediments 

and only scattered irregular bunches and 

nodules of chert, usually in its upper part. 

Fossils occur at many horizons from the bottom to the top of the formation, but, with the 

exception of small scattered corals and the 

abundant fragments of crinoid stems, they are 

rarely conspicuous and as a rule do not appear 

on weathered surfaces of the limestone. The 

general appearance of the Escabrosa formation 

is white or light' gray, but some dark-gray beds 

occur, particularly near the top. 

The fossils collected from the Escabrosa 

limestone were submitted to George H. Girty, 

who reported 1 that they probably represent 

the earlier hall of Mississippian time, including 

the Kinderhook and Osage divisions. The 

following are some of the characteristic species 

listed by him, with his comment: 

Menophyllum excavatum Girty. 

Syringopora aculeata Girty. 

Rhipidomella thiemei White. 

Rhipidomella michelina L 'Eveille. 

Leptrena analoga Phillips. 

Schuchertella inequalis Hall. 

Chonetes loganensis Hall and Whitfield. 

Productus ovatus Hall. 

Productus semireticulatis var. 

Spirifer centronatus Winchell. 

Spirifer mysticensis Meek. 

Brachythyris cf. B. peculiaris Shumard. 

Reticularia pseudolineata Hall? 

Syringothyris carteri Hall. 

Athyris lamellosa L 'Eveille. 

Eumetria marcyi Shumard. 

Pernopecten shumardanus Winchell. 

Myalina keokuk Hail. 

Phanerotinus paradoxus Winchell. 

Euomphalus luxus White. 

Platyceras sp. 

Phillipsia peroccidens Hall and Whitfield. 

Associated with some of the species in the above list were 

found others which probably indicate a slightly higher 

horizon than the Osage-in other words, one in the Mera1 Ransome, F. L., U.S. Geol. Survey Prof. Paper 21, pp. 46-54, 1904. 

mec group. There are such forms as Lithostrotion sp., 

Meekopora sp., Archimedes sp., Pustula cf. P. biseriata, 

and Spirifer cf. S. tenuicostata. On the other hand, no 

fossils of a well-marked Chester type have been found, so 

that so far as the evidence at hand is concerned the upper 

Mississippian is missing. It is also true that many of the 

striking Osage forms have not been found-for example, 

Schizophoria swallowi, Orthotetes keokuk, Spirijer grimesi, 

and Spirijer logani-nor the wealth of crinoids which 

characterize this horizon in certain areas in the Mississippi 

Valley. I am disposed to regard the absence of these 

Osage forms as due to local conditions but also to believe 

that upper Mississippian time is really in large part unrepresented. 

Measurements of the thicknesses of the Escabrosa limestone in different parts of the Bisbee quadrangle varied from 600 to 800 feet, 

the upper limit of the formation being difficult 

to determine with precision. The average 

thickness is taken as 700 feet. 

The Naco limestone, which overlies the 

Escabrosa conformably and with no distinct 

lithologic change, is made up chiefly of light-colored beds, which consist essentially of calcium 

carbonate. The beds range in thickness from 

a few inches to 10 feet but are usually thinner 

than those of the Escabrosa ljmestone. They 

differ from the latter also in texture, the typical 

Naco limestone being compact and nearly 

aphanitic, ringing under the hammer, and 

breaking with a splintery fracture, whereas 

the Escabrosa limestone is usually more granular and crystalline and crumbles more readily 

when struck. There are, however, exceptions 

to this rule, dense aphanitic beds occurring 

here and there in the Escabrosa formation and 

granular crinoidal beds being not uncommon in 

the Naco limestone. 

Fossils, particularly brachiopods, are much 

more abundant :in the Naco than in the Escabrosa limestone, and in some places they make 

up a considerable part of individual beds and 

weather out conspicuously upon exposed surfaces. 

While the greater part of the 3,000 feet or 

more of the Naco formation is made up of 

fairly pure gray limestone, certain thin beds 

of a faint-pink tint occur at different horizons 

and are often a useful means of distinguishing the Naco from the Escabrosa limestoneo 

These pink rocks, which weathering usually 

shows to have an inherent lamellar or shaly 

structure, are very fine grained and compact 

in texture. They effervesce freely with cold 

dilute acid and are evidently composed chiefly 
148 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

of calcium carbonate. Examination of natural surfaces with a lens, however, shows the 

presence of minute quartz grains and tiny 

flakes of mica. Chert is not uncommon in the 

Naco formation; it occurs as irregular bunches 

and nodules in beds of otherwise pure limestone or as the result of the silicification of thin 

fossiliferous beds throughout their thickness. 

It is also particularly abundant along and near 

zones of fissuring and faulting. 

According to Mr. Girty the fossils from the 

Naco limestone belong to two groups, one representing early anu the other later Pennsylvanian time. The earlier fauna include the following: 

Fusulina cylindrica Fischer de W aldheim. 

Chretetes milleporaceus Milne-E:lwards and Haime. 

Derbya crassa Meek and Hayden. 

Productus semireticulatus Martin. 

Productus cora D'Orbigny. 

Productus coloradoensis Girty. 

Pustula nebraskensis Owen. 

Postula semipunctata Shepard. 

Marginifera wabashensis Norwood and Pratten. 

Spirifer rockymontanus Macou. 

Spirifer cameratus Morton. 

Squamularia perplexa McChesney. 

Spiriferina kentuckyensis Shumard. 

Composita subtilita Hall. 

Hustedia mormoni Marcou. 

Dielasma bovidens Morton. 

Phillipsia major Shumard. 

The later fauna contains many species not 

yet described. The following forms have been 

dis crimina ted: 

Fusulina cylindrica Fischer de Waldheim. 

Michelinia? sp. 

Lophophyllum cf. L. profundum Milne-Edwards 

and Haime. 

Echinocrinus, several sp. 

Productus, semireticulatus type. 

Postula cf. P. norwoodi Swallow. 

Marginiferacf. M. wabashensisNorwood and Pratten. 

Martinia sp. 

Composita subtilita Hall. 

Plagioglypta cf. P , canna White. 

Worthenia sp. 

Murchisonia?, several sp. 

Euomphalus sp. 

Omphalotrochus, several sp. 

Cyclonema sp. 

Orthonema sp. 

Sphrerodoma sp. 

Bellerophon cf. B. crassus Meek and Worthen. 

Euphemus sp. ' 

This fauna, according to Mr. Girty, is closely 

related to that of the limestones of the Hueco 

Mountains, in western Texas. 

From the preceding descriptions it appears 

that Paleozoic time is represented in the 

Bisbee quadrangle by beds having a total 

thickness of a little over 5,000 feet. Of these 

the lower beds, 430 feet thick, are quartzites 

and the remaining 4,570 feet of beds are so 

predominantly calcareous that they may be 

collectively designated limestones. The Pennsylvanian series is represented by at least 3,000 

feet of strata (the Naco limestone), but only 

340 feet (the Martin limestone) can be as3igned 

to the Devonian, and the Silurian and Ordovician appear to be wholly without stratigraphic repres~ntation. 

TOMBSTONE GEOLOGIC SECTION. 

The Paleozoic section at Tombstone closely 

resembles that at Bisbee. The Bolsa quartzite has about the same thickness and character. The Abrigo limestone is 70 feet thinner 

than at Bisbee, and the bed of quartzite at its 

top also appears to be a littlethinner than itis in 

the region to the south. The Martin limestone 

has a larger proportion of shale at Tombstone 

than at Bisbee, but contains similar coralbearing beds and the fauna, according to . Dr. 

E. M. Kindle, is the same as that of the Martin 

limestone at the type locality. The beds at 

Tombstone maintain the same total thickness, 

340 feet, as at Bisbee. 

The Mississippian division of the Carboniferous is approximately 500 feet thick at Tombstone, as against 700feetatBisbee, but owing to 

the lack of any plane of lithologic distinction between the Mississippian and the Pennsylvanian 

in this region these figures are not very reliable. 

The Pennsylvanian (Naco) is well represented at Tombstone and consists almost exclusively of limestone. Of the fossils collected 

from the Naco limestone in the Tombstone 

district George H. Girty writes: 

The Pennsylvanian lots exhibit two faunal types which 

I understand occupy relatively higher and lower positions 

in the section. In the most characteristic lot of the upper 

horizon I recognized the following species: 

Echinocrinus sp. 

Productus ivesi Newbeny. 

Composita subtilita Hall. 

Deltopecten vanvleeti Beede. 

Pleurotomaria? sp. 

Bellerophon aff. B. stevensianus McChesney. 

Euphemus sp. 

Omphalotrochus obtusispira? Shumard. 

Trochus? sp. 

Orthonema soconoense Girty. 
u. S. GEOLOGICAL SURVEY 

I 

(~ 

)> 

~Mazatzal Peak t. 

rownR~ _/ 

L L.. 

//,.,...,. 

I 

-' 

0 

---... - ' - ... --"' 

, 

I 

/ 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 149 

The other lots add several species to this fauna, especially one or two large species of Schizostoma, a large Bellerophon, possibly B. majusculus, and a Murchisonia resembling M. terebra. 

These two Pennsylvanian faunas bear a close relationship to the faunas of the Magdalena limestone and Manzano group of New Mexico, and it seems highly probable 

that the upper Naco limestone will correlate with the 

Manzano and the lower Naco with the Magdalena. 

The fauna of the upper Naco is also related to a fauna 

found in the middle or upper part of the Hueco limestone. 

The lower Hueco fauna, while resembling in some respects 

that of the lower Naco, contains a good many species not 

yet found in the latter, and I am unable to state whether 

we have merely the same fauna with regional modifications or two faunas, one of which is older than the other. 

I rather incline to the former belief. 

The thickness of the Naco formation at 

Tombstone has not been measured, but probably amounts to several hundred feet. The 

limestone was extensively eroded before the 

deposition of the Mesozoic beds that unconformably overlie it in part. 

CLIFTON GEOLOGIC SECTION. 

At Clifton, 90 miles east-southeast of Globe/ 

about 1,500 feet of apparently conformable 

Paleozoic beds rest unconformably on Pinal 

schist and coarse red granite. At the bottom 

of the stratigraphic column is the Coronado 

quartzite, 200 feet thick, with a layer of conglomerate at its base as much as 50 feet thick. 

A section of the quartzite southwest of Morenci 

is described by Lindgren 2 as follows: 

Section of Coronado quartzite. 

Feet. 

White quartzitic sandstone. _______ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 50 

Banded pink and maroon quartzitic sandstone, forming precipitous bluff ____ . - - - ___ --- _ . _________ . . . . 162 

Quartzitic conglomerate. __ ._._._. __ ......... . .. _._ 10 

Sandstone .... _ ........... -..... - -.. - . . . . . . . . . . . . . . 3 

Quartzitic conglomerate (pebbles 1 inch in diameter) _ 8 

Coarse sandstone (base). _ . _ ........... ____ . . . . • • • . . 10 

243 

Above the Coronado quartzite lies the 

Longfellow limestone, 200 to 400 feet thick, 

which consists of cherty limestone in the 

upper part grading downward into shaly beds 

near the base. One of the sections given is as 

follows: 

1 Lindgren, Waldemar, The copper deposits of the Clifton-Morenci 

district, Ariz.: U . S. Geol. Survey Prof. Paper 43, 1905. See also U.S. 

Geol Survey Geol. Atlas, Clifton folio (No. 129), 1905. 

2 Op. cit. (Prof. Paper 43), p. 60. 

Section of Longfellow limestone one-fourth mile south of 

Modoc Peak. Feet. 

Buff limestone .............. _ . . . . . . . . . . . . . . . . . . . . . . 15 

Quartzitic sandstone.. ............................ . . 10 

Bluff of brownish-gray cherty limestone ..... _ .. _ ..... 140 

Shaly limestone_ ............... _ . . . . . . . . . . . . . . . . . . . 90 

Coarse gray sandstone .. _ .............. __ . _ . . . . . . . . . 10 

Sandy and shaly limestone (base) ....... _ ... _ .. _ ~ . . 115 

380 

Fossils are scarce in the Longfellow limestone. In the lower shaly part were found a 

few small lingulas and other forms that, while 

insufficient for a certain determination of age, 

were regarded by Dr. C. D. Walcott as indicating probably the uppermost part of the 

Cambrian. Near the top of the formation 

were found gastropods and fragments of trilobites which E. 0. Ulrich determined as early 

Ordovician. 1 Lindgren places the Coronado 

quartzite in the Cambrian and the Longfellow 

limestone in the Ordovician.2 

Resting upon the Longfellow limestone is 

the Morenci shale, consisting of a lower division of compact argillaceous limestone 75 feet 

thick and an upper division of dark clay shale 

about 100 feet thick. A few fossils were found 

in the lower division and were referred provisionally by Prof. H. S. Williams to the 

Devonian.3 

Overlying the Morenci formation is the 

Modoc limestone, 180 feet thick, of Mississippian age. 4 North of the exposures of the Modoc 

limestone and not in contact with it is a limestone formation 500 feet thick which Lindgren 

has called the Tule Spring limestone. It carries 

both Mississippian and Pennsylvanian fossils, 

and the lower 200 feet of the formation is regarded by Lindgren as in a general way equivalent to the Modoc limestone. The Tule Spring 

limestone is limited above by the pre-Cretaceous 

unconformity. 

ROOSEVELT GEOLOGIC SECTION. 

The gorge through which Salt River, after 

passing the Roosevelt dam, traverses the south 

end of the Mazatzal Range (see Pl. XXXI), 

affords an excellent section of the beds from 

the Mississippian down to the granite. This 

1 Op. cit. (Prof. Paper 43), p. 65. 

2 Idem, p . 59. ' 

s Idem, p. 69. 

• Idem, p. 72 (list of fossils). 
150 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

exposure has been very briefly noted by Lee,1 1 Its dip is 35° NE. The pebbles, unlike those 

whose diagrammatic section of the beds is re- in the typical Scanlan conglomerate of the 

produced here as figure 11. The explanatory Ray section, are well rounded and are as much 

lettering that evidently was intended to accom- as 9 inches in diameter. They are composed 

parry the diagram was inadvertently omitted of white quartz, brown fine-grained vitreous 

from Mr. Lee's paper, but the bed marked 1 quartzite, and a little red jasper. They lie 

is obviously Quaternary material, 2 is intended close together in a matrix of dull red-brown 

for Carboniferous limestone, 3 is the Troy coarse sandstone. On the whole, the conquartzite, 4 is the Mescal limestone, 5 is the glomerate locally resembles the typical Barnes 

Dripping Spring quartzite with the Barnes conglomerate of the Ray quadrangle more 

conglomerate at its base, 6 and 9 correspond than it does the Scanlan conglomerate of the 

to the Pioneer formation, and 10 is the Scanlan same area, of which, however, it is undoubtconglomerate. The numerals 7 and 8 desig- edly the stratigraphic equivalent. 

nate a thick sill of diabase in which the thin The Scanlan conglomerate is conformably 

layer (shale~) is probably not so persistent as overlain by rather coarse brown cross-bedded 

is indicated, and 11 is coarse pre-Cambrian arkosic sandstone, flecked with small light 

granite. Lee 2 cites a personal communica- spots, like those in the typical Pioneer shale, 

FIGURE 11.-Section through Salt River gorge near Roosevelt, Ariz., looking northwest. (After W. T. Lee.) See text for explanation. 

tion from Dr. C. D. Walcott to the effect that 

"the Carboniferous limestones rest directly 

and unconformably upon the quartzites and 

argillites of the Algonkian" and agrees that all 

the beds below the supposed unconformity 

(which he did not himself see 3) are Algonkian. 

The base of the sedimentary series is exposed about half a mile downstream from the 

dam, where the Scanlan conglomerate, here 

30 feet thick, rests on an erosion surface of 

coarse red granite. This color is the result of 

pre-Cambrian we~thering, and is characteristic of this old surface throughout central 

Arizona. The red tint generally fades to gray 

a short distance from the con tact. The surface shows gentle undulations, and the conglomerate is probably variable in thickness. 

1 Lee, W. T., Underground waters of Salt River valley, Ariz.: U.S. 

Geol. Survey Water-Supply Paper 136, pp. 96-98, 1905. 

. 2 Idem, p. 96. 

a Oral communication. 

and containing a few small pebbles. The lowest 

three beds of this sandstone are each about 10 

feet thick and are separated by partings of 

maroon shale . . Above th~m both the sandstone beds and the layers of shale become 

thicker for about 140 feet, to the base of a 

great diabase sill, probably 700 to 800 feet 

thick. Despite the size of this intrusion the 

shales above and below it show no metamorphism other than slight baking and hardening. 

Above the diabase lies about 100 feet of typical 

spotted maroon Pioneer shale. 

The shale is overlain by the Barnes. conglomerate. The pebbles are smaller than 

those in the typical conglomerate of the 

Globe-Ray region, most of them being less than 

4 inches in diameter, and there is a rather large 

proportion of sandy matrix. As exposed in the 

cliffs, high above the river, the Barnes conglomerate appears to be rather better developed 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 151 

than in the roadside exposure studied, where 

its thickness is from 15 to 20 feet. 

Overlying the Barnes conglomera,te is the 

Dripping Spring quartzite, which has an estimated thickness of 500 to 600 feet. For about 

140 feet above its base the banded reddishbrown quartzite is separated rather indisti1ictly 

by thin partings of dark-red shale into beds 10 

feet or less in thickness. Above this zone the 

beds are thinner and show some faint crossbedding. The upper 180 feet of the formation 

consists of thinly laminated striped dull-red 

and black quartzite, which as a rule forms a 

cliff. The cliff dwellings of the Tonto National 

Monument, about 4 miles southeast of the dam, 

are in these upper beds. So far as seen the 

Dripping Spring quartzite at Roosevelt, as well 

as near Ray, is free from pebbles. 

On top of the Dripping Spring quartzite is the 

Mescal limestone, which is very well exposed at 

Roosevelt, especially along the Phoenix road 

from the dam to a point about 100 yards beyond 

the first sharp turn to the east. The beds dip 

25° NE., and the plane of contact between the 

Dripping Spring quartzite and the Mescal limestone, if projected across the gorge, would intersect the dam about halfway between the top 

and the bottom. 

The Mescal near the Roosevelt dam consists 

of hard dolomitic cherty limestone in beds that 

are for the most part less than 2 feet thick, with 

little or no shaly material. The roughly parallel but wavy and irregular layers of chert so 

characteristic of the formation farther south 

are equally conspicuous near Roosevelt in 

weathered exposures transverse to the bedding 

planes. The general color of the formation is 

darker than at Ray, and the chert bands near 

the base are black and flinty. On fresh fractures the Mescal limestone is gray, pink, or 

yellow. The local thickness of the formation 

is about 300 feet. Overlying the limestone, as 

at Ray, is a flow of rusty basalt, from 40 to 60 

feet thick, as exposed near the east end of the 

dam, and vesicular both at top and bottom. 

Overlying the basalt flow is the local equivalent of the Troy quartzite, whieh here may be 

more appropriately called the Troy sandstone. 

As exposed along the road between the dam 

and the cement quarry, this formation is made 

up as follows: 

Section of Troy sandstone. 

3. Cross-bedded pebbly sandstone. Lower beds massive and weathering dark reddish brown. Lower 

massive bed near dam beautifully striped in red 

and gray. Upper beds thinner, mostly under 2 

Feet. 

feet, with calcareous cement .................. 100 

2. Cross-bedded pebbly sandstone, with layers of 

brown, micaceous sandy 13hale..... . . . . . . . . . . . . . 40 

1. Dark-brown shale grading upward by interbedding 

into sandstone... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Base. 

The Troy sandstone at Roosevelt is much 

thinner, therefore, than in the Ray-Globe 

regwn. 

Overlying the Troy with no conspicuous 

difference in general appearance is a series of 

generally rather thin-bedded limestones and 

sandstones or quartzites. The lower beds are 

very compact gray limestones, which are succeeded by impure sandy limestones interbedded with calcareous sandstones and some 

quartzite. The topmost bed is shale which 

weathers to thin yellow flakes and is considered to be lithologically and stratigraphically identical with the yellow shale that is 

believed to mark the top of the Devonian in 

the Ray-Globe region. The formation as a 

whole is more sandy than the Martin limestone of the Ray quadrangle and is less 

fossiliferous. A few fossils were collected in 

1912 from the top of the sharp hill just east 

of the dam and south of the cement quarry, 

but Dr. Kindle found that only one species, 

probably Schizophoria striat:ula (Schlotheim) 1 

is represented. He writes, in a personal 

letter: 

Before offering a final opinion as to the age of the fauna 

represented by this shell I would like to see another 

collection, including other species. I am inclined provisionally to refer the beds represented by this single 

species to the Devonian. 

The locality was again visited in 1 a l4 and 

additional fossils were collected. Edwin 

Kirk, of the United States Geological Survey, 

to whom they were submitted, lists them as 

follows: 

Cladopora sp. 

Schizophoria stratula var. australis Kindle. 

Schuchertella sp. 

Camarotrechia contracta Hall(?). 

Camarotrechia sp. 

Spirifer whitneyi var. animasensis (Girty). 

Modiomorpha sp. 
152 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Mr. Kirk remarks that this fauna can be ites that have since been called the Dripping 

correlated with that of the Martin limestone Spring and Troy quartzites, but he refers all 

of Bisbee and that of the Ouray limestone of exposures of both to the ''Tonto sandstone." 

Colorado. He states that there can be no Gilbert also applies the same name to all the 

doubt of the Devonian age of the material. arenaceous rocks below the Redwalllimesoone, 

No measurement of the Devonian near but it is possible that he had only distant 

Roosevelt was made, but the thickness is esti- views of the Dripping Spring quartzite, which 

mated roughly at 300 feet. apparently does not appear in the plateau 

Overlying the yellow shale at the top of the escarpment. Reagan describes a number of 

Devonian beds is the light-gray pure and com- stratigraphic sections and notes certain sediparatively massive Carboniferous limestone. ments as being unconformable under the 

This is the rock that was quarried for cement "Tonto sandstone" and therefore of Algonkian 

during the construction of the dam. It forms age. These older rocks probably include the 

the little knoll northwest of the dam on which I Pioneer shale, but how much n1ore is not clear 

stands the hotel. Fossils were collected by from his descriptions. Neither is it clear that 

W. T. Lee from the limestone near Roose- he has in all places applied the name "Tonto 

velt and from Windy Hill, about 5 miles east sandstone" to the same formation. Attempts 

of the dam. G. H. Girty,t to whom they were to identify in his published sections the formareferred, identified the fauna as early Mississip- tions discriminated in the Roosevelt and Grand 

pian and lists the following forms: Canyon sections have met with little success. 

Zaphrentis sp. 

Menophyllum excavatum Girty. 

Cyathophyllum sp. 

Syringopora l'lurcularia Girty. 

Syringopora aculeata Girty. 

Leptopora typa Winchell. 

Crinoidal fragments. 

Rhipidomella sp. 

Schuchertella inooqualis Hall. 

Productus ovatus Hall. 

Camarotmchia metallica White. 

Spirifer centronatus Winchell. 

Spirifer sp. 

Platyceras sp. 

Bellerophon sp. 

Composita humilis? 

Fish tooth. 

It appears from the foregoing description that 

the stratigraphic column at Roosevelt is composed of the same formational units as that of 

the Globe-Ray region and that the Mississippian limestone lies conformably on the 

Devonian. 

CANYON CREEK GEOLOGIC SECTION. 

The region adjacent to Fort Apache, northeast of Roosevelt, received some attention 

from the geologists of the Wheeler Survey 2 

and was later described by Reagan.3 Marvine 

at least, in his trip from Fort Apache to the 

Gila Valley, undoubtedly saw the two quartzI Lee, W. T., Underground waters of Salt River valley, Ariz.: U.S. 

Geol. Survey Water-Supply Paper 136, pp. 97-98, 1905. 

2 Gilbert, G. K., U.S. Gaol. Surveys W. 100th Mer. Rept., vol. 3, pp. 

163-165, 1875. Marvine, A. R., idem, pp. 215-225. 

a Reagan, A. B., Geology of the Fort Apache region in Arizona: Am. 

Geologist, vol. 32, pp. 265-308, 1903. 

One of Gilbert's sections (No. IX, Aubrey 

Cliff, at Canyon Creek) interpreted in the light 

of present knowledge of Arizona stratigraphy 

is given in the correlation chart of Plate XXV 

(p. 136). The original description is. as follows: 

1. Coarse uncemented gravel, of quartzite and 

gneiss bowlders. ______ ........ -.... --- ... . 

2. Massive cross-bedded yellow sandstone ....... . 

3. Compact gray lim..estone; Spirijer cameratus .•• 

4. Red and purple sandstone, soft at top, massive 

below ____________ .. ___________ - ______ ... - -

5. Alternation of gray limestone and red shale: 

a. Limestone, 5 feet. 

b. Unseen; shale (?), 100 feet. 

c. Limestone, Athyris subtilita, 10 feet. 

d. Red calcareous sandstone, 4 feet. 

e. Shale, 40 feet. 

f. Limestone, 4 feet. 

g. Unseen; shale (?), 25 feet. 

h. Massive limestone, 10 feet. 

i. Unseen; shale (?), 75 feet. 

j. Limestone, 2 feet. 

k. Unseen; shale (?), 50 feet. 

6. Sandstone: 

a. Brown to red, coarse vitreous sandstone, massive to shaly, 100 feet. 

b. Gray fine-grained sandstone, weathering red, falling apart in angular 

blocks, 75 feet. 

c. Shaly calcareous sandstone, 75 feet. 

d. Vitreous, red, purple, and white 

sandstone, 150 feet. 

e. Coarse siliceous conglomerate, 25 feet. 

7. Hornblende rock and schists; unconformable. 

Feet. 

20 

525 

65 

500 

325 

425 

500+ ---

2: 360+ 

In this section No. 2 is unquestionably the 

Coconino sandstone, 3 and · 4 are probably the 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 153 

Supai formation, although it is thinner than that indicated diagrammatically in figure 12. 

might be expected, 5 presumably is the Red- The oldest formation seen in this traverse is the 

wall, and 6 is possibly the Tapeats ("Tonto") Dripping Spring quartzite. This forms the 

sandstone, although it appears to be too thick lower line of cliffs that are conspicuous along 

for that formation. The section as a whole the west face of the rar.ge for 7 or 8 miles north 

conforms to the Grand Canyon type and is of Salt River. It has been considerably 

decidedly different from the Roosevelt and I faulted, so that in pla.ces isolated down-dropped 

Ray-Globe sections. blocks lie in front of the main escarpment, and 

Gilbert 1 gives a section on Carrizo Creek, has also been intruded by diabase. The botwhich is about 20 miles east of Canyon Creek, tom of the quartzite was not seen, but the beds 

that indicates the presence of 1,200 feet of exposed were estimated to have a thickness 

Supai rocks above the Redwall, but his de- between 300 and 500 feet. 

scriptions suggest that there may be some Above the quartzite is an enormous sill of 

difficulty in determining the stratigraphic diabase probably 1,000 feet or more in thicklimits of the formations in this region. ness, dipping to the east, like the quartzite, at 

Another of his sections (No. XI) measured 10° to 15°. In consequence of its greater susnorth of and near Fort Apache gives 1,390 feet ceptibility to decomposition and erosion, the 

w. E., 

FIGURE 12.-Diagrammatic section across the Sierra Ancha, Ariz., near Aztec Peale 

of beds that from his description would probably now be identified as the Supai formation. 

SIERRA ANCHA AND MAZATZAL RANGE. 

CARR'S RANCH AND VICINITY. 

The western front of the Sierra Ancha, as 

seen from Roosevelt, is bold and precipitous. 

Even so distant a view reveals very clearly the 

general structure of the range-that of a block, 

probably a fault block, uptilted along its western margin. Dark cliffs of red-brown quartzite in the lower part are succeeded along the 

crest by beds so much lighter in hue that they 

suggested at first the presence of the Carboniferous limestones. 

An ascent of the range was made from Roosevelt in 1914 by way of Carr's ranch to Aztec 

Peak, and its general structure was found to be · 

1 Gilbert, G. K., op. cit., p. 164. 

diabase has weathered back, leaving a broad 

dip-slope bench on the quartzite, which is followed for many miles by the road from Salt 

River to Carr's ranch. (See fig. 12.) Ravines 

leading down from the upper part of the range 

cross this bench and in the quartzite become 

deep, narrow chasms with vertical walls. A 

few included masses of altered Mescal limestone were noted in the diabase, and remnants 

of the limestone appear to overlie the igneous 

rock in some places. Evidently here, as in the 

Globe-Ray region, the principal diabase intrusion took place at the Mescal horizon. 

Carr's ranch is situated on the diabase sill at 

an elevation of about 5,600 feet. A few miles 

northeast of the ranch on the north side of 

Workman Creek, a section of the beds that 

overlie the diabase was examined. The results are as follows, the thicknesses having been 

determined by aneroid barometer. 
154 SHORTER ODNTR.IBUTIONS TO GENERAL GEOLOGY, 1916. 

Section in Sierra Ancha. 

Top of ridge. 

8. Hard white quartzitic sandstone, with streaks of 

well-rounded quartz pebbles, none of which 

are over 2 inches in diameter. Weathers light 

red or pinkish brown. Beds 5 to 6 feet thick 

near base but str'atification less distinct above. 

Some cross-bedding at low angles. Forms a 

cliff ...................................... . 

7. Fairly hard coarse to pebbly pink-buff sandstone. 

Feet. 

200 

GREENBACK VALLEY AND VICINITY. 

About 9 miles west-northwest of Carr's 

ranch, also on the west slope of the Sierra 

Ancha, is Greenback Valley, a little basin about 

2 miles in diameter; floored chiefly with diabase 

Grains smaller than peas. Grades downward 

into No.6 ................................. . 

6. Massive, generally fine-grained gray sandstone. 

Weathers dingy white and forms a rough ledgy 

slope above cliff noted below. Fairly soft and 

could be easily worked as a building stone. 

Texture uneven, owing to imperfect mixing 

and inclosed in part by cliffs of Dripping Spring 

quartzite. The quartzite, as in parts of the 

Globe-Ray region, has been extensively invaded 

by the diabase, both as thick sheets and as 

75 crosscutting masses. In places blocks of the 

quartzite strata were evidently at one time 

completely enveloped in the diabase magma. 

The basal rock in this vicinity is a coarse 

porphyritic biotite granite. This is exposed of grains of different size ..................... . 

5. Massive fine-grained pink to buff sandstone. 

Forms a cliff. Contains well-rounded grains 

of pink feldspar and white quartz, the largest 

the size of mustard seeds. Layers of quartz 

pebbles as much as 2 feet thick in upper 100 

feet. Pebbles fairly well rounded and 4 inches 

or less in diameter, in places scattered through 

75 In the deep gorge of Sallymay Creek, 5 miles 

east of the valley, and at several places along 

the west base of the range between Greenback 

Valley and Tonto Creek. 

the sandstone ............................... . 

4. Fine-grained homogeneous pinkish sandstone. 

Bedding not distinct. Weathers in slabs and 

as a rule forms a steep slope ... ~ .............. . 

200 

300 

Resting upon the granite on Sallymay Creek 

is a basal conglomerate about 6 feet thick 

where seen. The lower 3 feet is coarse with 

well-rounded ' pebbles of white quartz, pink 

3. Fine-grained red-brown, rather flaggy sandstone. 

Rests directly on basalt. Contains flakes and 

thin layers of red shale ..................... . 

2. Vesicular bMalt flow, forming a red-brown bluff . 

. Thickness not closely determined, probably 

quartzite, and red jasper, the largest 8 inches in 

diameter, in an arkosic matrix. Overlying the 

conglomerate is a brownish-redarkosicquartzite 

50 containing abundant particles of pink feldspar. 

Between some of the quartzite beds are thin 

layers of sandy shale. This quartzite is prob- about ...................................... . 

1. Thin-bedded cherty limestone, cons~derably 

metamorphosed and containing serpentine, 

tremolite, and pyrite. Not well exposed. 

50 ably the stratigraphic equivalent of the Pioneer 

Thickness uncertain, probably about ......... . 250 

Intrusive diabase at base. 

From the top of this section to the summit 

of Aztec Peak, on Baker Mountain, the difference in elevation is about 200 feet. This 

interval appears to be occupied by a massive 

medium-grained quartzitic sandstone, on which 

weathering brings out a lamination parallel 

with the bedding. In places this sandstone is 

rusty and contains little ball-like concretions 

an inch or two in diameter. Although no 

unconformity was detected, the possibility of 

a stratigraphic break between this sandstone, 

or some part of it, and the sandstones noted 

in the preceding sectiQn can not be denied. 

The metamorphosed limestone above the 

diabase at the base of the section is probably 

the Mescal limestone. Above it is at least 900 

feet of sandstone, which is supposed to be the 

stratigraphic equivalent of the Troy quartzite. 

shale farther south. It is at least 150 feet · 

thick and may be considerably thicker. Overlying it is a sheet of diabase, on top of which 

is the cliff-making Dripping Spring quartzite. 

Whether the Barnes conglomerate is present 

above or below the diabase on Sallymay Creek 

was not ascertained in the short time spent in 

this locality. 

Just north and east of Greenback Valley the 

range exhibits well the generally broad-topped 

character which originally suggested its Spanish name. From the brink of the westwardfacing cliffs the surface slopes gently eastward, 

much of it being a dip slope on the tops of the 

Dripping Spring quartzite. Here and there 

are remnants of thin-bedded cherty limestone, 

presumably the Mescal limestone. The top 

of Greenback Mountain, east of Greenback 

Valley, is such a remnant. 

On the north slope of Chubb Mountain, 

near the point where a trail from Greenback 

Valley descends a very steep slope into the 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 155 

canyon of Sallymay Creek, the diabase' is overlain, with igneous contact, by a little pink 

quartzite, which is succeeded conformably by 

15 to 20 feet of hard conglomerate. This 

closely resembles the typical Barnes conglomerate, but here, as in other places near Greenback Valley, the Dripping Spring quartzite 

and older formations have been so broken and 

displaced by the diabase intrusion that it is 

not always possible to be sure of the stratigraphic relations without much more detailed 

work than can be done in a hasty reconnaissance. 

From Clanton's ranch, on Tonto Creek, about 

4!- miles above Cline, another traverse was 

made to the crest of the Sierra Ancha, which 

was reached at a point 4 miles north-northwest 

of Greenback Valley and 7 miles southeast of 

Gun Creek. The western slope of this part of 

the range was found to consist of numerous 

fault blocks, each consisting of the basal 

granite, Scanlan conglomerate, Pioneer shale, 

Barnes conglomerate, and Dripping Spring 

quartzite, with great sills of diabase, all lying 

nearly horizontal. The faults are apparently 

normal and form a series of steps leading to the 

crest of the range, which at the locality visited 

is a plateau nearly 6,000 feet in altitude, corresponding to the upper surface of the Dripping 

Spring quartzite and surmounted by a few 

patches of cherty limestone, probably theMescal. The Scanlan conglomerate is 5 to 6 feet 

thick and is made up of fairly well rounded 

pebbles as much as 8 inches in diameter. It 

rests on the same coarse red granite that is 

seen in Sallymay Canyon. Above the Scanlan 

conglomerate is some typical Pioneer shale, but 

higher in the section the shale becomes interbedded with quartzite, and, as the Barnes conglomerate does not appear to be strongly developed, the plane between the Pioneer shale 

and the Dripping Spring quartzite was not very 

satisfactorily determined in the short time 

given to the examination. The Pioneer formation is probably not over 200 feet thick in 

this part of the range. The Dripping Spring 

quartzite, however, is prominently developed 

and generally forms a horizontally banded redbrown cliff. It has a local thickness of about 

500 feet. 

From Roosevelt northward the valley of 

Tonto Creek, deeply filled with fluviatile and 

30830°-17-11 

lacustrine deposits, is 4 or 5 miles in breadth 

and contains a recent alluvial flood plain a 

mile or so wide along the creek. Near the 

mouth of Gun Creek this valley con tracts 

to a gorge in schist and a sharp ascent of about 

500 feet over hills of pre-Cambrian schist 

leads up to Ton to Basin. This is an irregular 

depression whose hilly floor, ranging from 

3,000 to 6,000 feet in altitude, is bounded 

very defmitely on the north by the great escarpment of the Mogollon 1-.iesa and is less completely closed in on the west by the linear 

crest of the Mazatzal Range and on the southeas t by the northern part of the Sierra Ancha. 

The floor of the basin is composed mainly of 

granite and other pre-Cambrian intrusive 

rocks, with some schist, covered in part by 

Tertiary and Quaternary volcanic rocks and 

gravels. 

DELSHAY BASIN. 

Delshay 1 Basin is a well-marked upland 

depression, about 3 miles in diameter, on the 

west slope of the Sierra Ancha near the north 

end of that range. It is drained through deep 

canyons by Gun Creek and its tributaries. 

The basin, whose floor has a general altitude 

of 4,500 to 5,000 feet, is best reached by road 

and trail from Hardt's ranch, in Tonto Basin. 

The fundamental rocks between Hardt's 

ranch and Delshay Basin are crystalline sericitic and greenstone schists, which strike in 

general northeast and dip i:wrthwest at high 

angles. These are cut by dikes of granite 

porphyry and of rhyolite that is in places 

schistose. A bold ridge of the schistose rhyolite forms the west wall of the basin, and Gun 

Creek flows in a wild gorge along its eastern 

base. Closely associated with the schist are 

masses of quartzite that lie unconformably 

beneath the nearly horizontal Cambrian quartzites and are described on pages 157-159. Some 

beds of magnetitic quartzite, striking northeast, form part of the schist series in Delshay 

Basin, and occupy a belt perhaps a quarter of 

a mile wide and at least a mile in length. The 

deposits appear to be lenticular, and the individual masses are 50 feet in maximum width. 

There are all gradations between nearly pure 

magnetite and dark ferruginous quartzite. 

1 This name, in use by the cattlemen of the region, is said to be that of 

a former Indian chief. Some uncertainty attaches to the spelling, which 

is that given to me at Hardt's ranch. 
156 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY i 1916. 

The material was evidently laid down in preCambrian time as a magnetitic sand and has 

been folded and squeezed with the other rocks 

of the schist complex. 

Southeast of the magnetite belt in Delshay 

Basin is a belt from 1 to 2 miles wide of a peculiar conglomerate that is clearly a part of the 

schist complex, has been thoroughly squeezed, 

and is decidedly schistose. The cleavage 

planes stand nearly vertical. The "pebbles" 

are mostly flat flakes of slate and schist, as 

much as 8 inches long, with a few round pebbles of harder material. The matrix consists 

of grains of quartz and pink feldspar. Clearly 

the schistose terrane in this region has a com-

. plex history and records more than one period 

of dynamio metamorphism. To the east of 

the · schist conglomerate Delshay Basin is 

floored with coarse red pre-Cambrian granite. 

Presumably the schist conglomerate was originally deposited on this granite, but the contact 

was not seen. 

On the east and south the rocks that have 

been mentioned as exposed in the floor of Delshay Basin are overlain unconformably by 

nearly· hm:izontal beds, whose edges are exposed in the steep slopes and cliffs that shut 

in the basin on those sides. A section of these 

beds up the east wall of the basin is as follows, 

the thicknesses being approximate only: 

Section on east side of Delshay· Basin. 

Crest of Sierra Ancha. Feet. 

13. Purplish brown calcareous shale, apparently interbedded with impure cherty limestone. 

Slope littered with rusty spongy chert........ 125 

12. Smooth slope with no exposures. Fragments of 

thin-bedded rusty sandstone and shale with 

some very impure dolomitic limestone. Abundant fragments of dark vesicular chert. A Jittle 

decomposed igneous material. Small outcrop 

of light gray limestone at base.. . . . . . . . . . . . . . . . 60 

11. Smooth slope with few outcrops. Rusty cherty 

detritus in soil, with fragments of thin-bedded 

sandstone and shale....... . . . . . . . . . . . . . . . . . . . . 40 

10. Fine-grained, rather rusty quartzitic sandstone. 

Beds a little thicker than in No. 9, the maximum being 3 feet ............................ 100 

9. Thin~bedded flaggy sandstone with some shale. 

Weathers in buff, brown, and rusty shades. 

Some beds show worn casts. Forms gentle 

slope with poor exposures .................... 100 

8. Massive pink quartzitic sandstone; weathering 

with pits like No.6. Prominent cliff maker... 75 

7. Fine-grained pink to yellow-brown quartzitic 

sandstone. IJike No. 6, but in thinner beds; 

forms slope.................................. 25 

Feet. 

6. Massive pink quartzitic sandstone with, in lower 

part, a few rather angular pebbles of white 

quartz as much as 4 inches in diameter. Prominent cliff maker. Weathers with numerous 

round but rather irregular pits, mostly less than 

1 inch across................................. 50 

5. Conglomerate with rather angular pebbles of white 

quartz. Thickness apparently variable, where 

seen about.................................... 2 

4. Massive fine-grained red-brown sandstone. Beds 

12 feet or more thick, but bedding inconspicuous. Some cross-bedding at low angles, not 

over 30°. Less noticeably arkosic than beds 

below. Forms clif-f5l ............... · ........... 150 

3. Apparently fine-grained red-brown sandstone. 

Exposures in part poor or lacking ............... 100 

2. Coarse red-brown arkosic, quartzitic sandstone in 

beds as much as 6 feet thick. Contains illdefined layers of conglomerate with pebbles 

mostly under 1! inches and not well rounded. 

Some layers of spotted red shale......... . . . . . . 150 

i. Conglomerate with poorly rounded pebbles of 

white quartz in a coarse arkosic matrix. Pebbles mostly under 2 inches.................... . 3 

(This conglomerate is apparently better 

developed and has larger pebbles in neighboring parts of the same ridge, as indicated by 

blocks in streamways.) 

Bottom of section coarse red granite, of which 

upper 4 or 5 feet appears to have been disintegrated before overlying sediments were laid 

down. 

The foregmng section is not readily divisible 

into the units of the Globe-Ray section, and· 

evidently the changes that take place in the 

older Paleozoic sediments along ·the Sierra 

Ancha require something more than a few 

traverses to determine their· character and 

significance. A careful stratigraphic study 

carried continuously along the range would undoubtedly yield interesting results. N evertheless, it is believed that the section given is 

much more closely related to the Globe-Ray 

section than to the sections farther north that 

will presently be described. The thin-bedded 

impure cherty limestone at the top of the section is probably the stratigraphic equivalent 

of the Mescal limestone, and the sandstones and 

conglomerates below probably represent the 

Scanlan conglomerate, Pioneer shale, ·Barnes 

conglomerate, and Dripping Spring quartzite. 

The great intrusions of diabase are not represented in the part of Delshay Basin seen, and 

the absence of this rock may account for the 

fact that the arenaceous beds are less quartzitic ·than farther south and lack certain other 
SOME PALlj)OZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 157 . 

features that are characteristic of these rocks 

in the southern part of the range, at Roosevelt 

and in the Globe-Ray region. 

PRE-CAMBRIAN SEDIMENTS OF THE NORTHERN 

SIERRA ANCHA AND OF THE MAZATZAL 

RANGE. 

·One of the most interesting of the results of 

the two reconnaissance trips made into the 

region adjacent to Tonto Basin was the recognition of a thick series of quartzites, conglomerates, and shales that is unconformably 

beneath the Apache group and its stratigraphic equivalents. A brief reference to 

these rocks has already been published.1 

The unconformity between these pre-Cambrian strata and the nearly horizontal Paleozoic 

beds is clearly shown just north of Delshay 

Basin. Here a prominent bold hill lying just 

east of Gun Creek and north of a tributary 

that is locally known as Sheep Basin Draw is 

composed of this older quartzite. The rock 

was not closely examined at this locality, but 

the beds are evidently some hundreds of feet 

in total thickness and are complexly folded and 

faulted. Just east of this hill, which closes 

Delshay Basin on the north, are the cliffs in 

which are displayed the nearly horizontal beds 

described in the section on page 156. These 

beds were not seen at this locality in actual 

unconformable oontaot with the older quartzite, but the contrast in character and structure 

is so obvious that no doubt is entertained of 

the existence of a pronounced unconformity. 

The relation of the older quartzite to the schist 

terrane is apparently intimate, and the quartzite has shared to some extent in the vigorous 

deformation to which the schistose rocks have 

been subjected. 

:The pre-Cambrian strata occur also in the 

northern part of the Mazatzal Range and 

were here more closely examined. Mazatzal 

Peak, about 8,000 feet in altitude, is composed 

chiefly of these rocks, which appear to constitute the higher portion of the range from 

this rugged summit northward. 

From Hardt's ranch a traverse was made up 

Deer Creek, which heads south of Mazatzal 

Peak and flows eastward into Rye Creek a 

tributary of Tonto Creek. The lowest ~nd oldest rocks exposed on Deer Creek are schists. 

1 Ransome, F. L., Quicksilver deposits of the Mazatzal Range Ariz · 

U.S. Geol. Survey Bull. 620, pp. 114-117, 1915 (Bull. 620-F). ' .. 

These schists, with those exposed at Hardt's 

ranch and in Delshay Basin, are part of a 

northeasterly belt that crosses the Mazatzal 

Range obliquely between the pre-Cambrian 

granite of Mount Ord and the quartzite mass of 

Mazatzal Peak and apparently continues northeastward past the north end of the Sierra 

Ancha. The descriptions given by Reagan 1 

are not quite clear on this point, but the belt 

of schistose rocks, irregularly overlapped in 

places by younger formations, appears to 

extend eastward across the upper parts of 

Cherry, Canyon, and Cibicu creeks, beyond 

which it probably passes under the horizontal Paleozoic beds of the Arizona Plateau. 

Where seen in the Tonto region these schists 

have considerable lithologic variety. They 

include sericite schist, greenstone schist, brown 

and dark-gray slates, schistose grits and conglomerates, hematitic schist, thin-bedded dolo- ' 

mite and red jasper, and beds of quartzite or 

quartz schist. Associated with these rocks are 

some rhyolite, generally schistose in part, and 

small masses of other ancient igneous rocks. 

Where it crosses the Mazatzal Range the belt 

of exposures is about 5 miles wide. To the 

northeast, where it crosses Tonto Basin and 

extends past the north end of the Sierra Ancha, 

the area of schistose rocks is probably at least 

15 miles wide. The belt contains the quicksilver deposits of the Mazatzal Range. 2 It is of 

especial interest in connection with the subjects 

discussed in the present paper, as it appears to 

mark a pronounced change from north to 

south in the character of the pre-Devonian 

Paleozoic sections of this part of Arizona. 

This will be brought out more fully in subsequent pages. 

At an altitude of about 5,600 feet on the 

north side of the middle fork of Deer Creek the 

basal bed of the pre-Cambrian sedimentary 

beds rests on red oxidized rhyolite that shows 

well-developed flow structure. The relation 

of this old rhyolite to the schists was not ascertained, but it is probably a part of the schist 

complex. The beds strike N. 33° E. and dip 

about 70° NW. This attitude agrees fairly 

well with the general strike and dip of the 

schists and suggests that the beds about to be 

1 Reagan, A. B., Geology of the Fort Apache region in Arizona: Am. 

Geologist, vol. 32, pp. 265-308, 1903. 2 Ransome, F. L., Quicksilver deposits of the Mazatzal Range, Ariz : 

U.S. Geol. Survey Bull. 620, pp. 111-128, 1915 (Bull. 620-F). 
. 158 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

described have taken part in at least some of 

the pre-Cambrian deformation to which the 

schists have been subjected. 

At the base of the sediments is a brick-red 

detrital rock made up of flakes of schist in 

an abundant matrix, apparently also composed of minute schist particles with an occasional grain of quartz. The material suggests 

an indurated oxidized stony soil. It is about 

80 feet thick. Overlying it without any sharp 

plane of demarcation is a conglomerate about 

2 feet thick, with rather sparse pebbles of 

rhyolite and red jasper as much as 5 inches 

in diameter. The conglomerate in turn grades 

upward into quartzite. The quartzite is very 

hard ~nd vitreous and is generally reddish or 

brown. Much of it is banded parallel with the 

bedding planes. Little seams or films of specularite on joint planes are rather characteristic. 

E. 

The first rock to be seen in ascending the 

ravine is a large body of quartzite folded into a 

sharp anticline and apparently faulted against 

shales on the northwest. These shales resemble nothing I had previously seen in Arizona. 

They are gray-green, weathering yellow, fairly 

hard, and only moderately fissile, and they 

effervesce in acid when powdered. Evidently 

they are somewhat dolomitic. For about 50 

feet from their top they alternate with thin beds 

of quartzite and conglomerate. The conglomerate layers are less than a foot thick and carry 

pebbles of quartz and red jasper. The strike 

of the shales where seen is northeast and the dip 

northwest at 55° in the bottom of the canyon 

and at 45° near the top of the formation. The 

stratigraphic base of the shale was not seen, but 

the apparent total thickness of the beds exposed 

was very roughly estimated at 1,000 feet. 

w. 

FIGURE 13.-Diagrammatic section on North Fork of Deer Creek, Mazatzal Range, Ariz. 

Between many of the beds are thin partings of 

hard red micaceous shale showing worm casts. 

These beds were found to continue up the 

precipitous slope to an altitude of 6,500 feet, 

but at that point the traverse had to be abandoned. The apparent thickness is at least 

1,400 feet, but there is possibly some duplication of folding or faulting. Similar quartzitic 

beds were observed to continue some hundreds 

of feet higher, to the crest of the ridge, and 

quartzite with blocks of coarse grit or fine conglomerate were the only rocks observed in the 

talus. The pebbles in the conglomerate are as 

a rule smaller than peas and consist mostly of 

quartz and red jasper. 

Another traverse was made up the North 

Fork of Deer Creek. The relations there seen 

are indicated in the rough sketch shown as 

figure 13. This is not drawn to scale and no 

attempt was made to measure the thicknesses 

of the beds. 

The shale is overlain, with apparent conformity, by hard brown quartzite in beds generally 

less than 2 feet in thickness. The dip grows 

less toward the top of the slope, and at an elevation of 700 feet above the north fork the beds 

lie in gentle folds with dips of 25° and less. 

The quartzite beds vary in color, but most are 

reddish. Layers of small pebbles of quartz and 

red jasper are fairly abundant. 

The same pre-Cambrian quartzites described 

as occurring in the vicinity of Deer Creek and 

Mazatzal Peak appear to continue along the 

crest of the Mazatzal Range to its northern 

tern1ination at North Peak, the base of the 

range being schist, granite, and probably other 

ancient crystalline rocks. 

The northernmost point at which the preCambrian sediments have been recognized in 

this part of Arizona ia on Pine Creek, in the 

vicinity of Natural Bridge, about 8 miles northwest of Payson and 12 miles north of North 
SOlVIE PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 159 

Peak. At Natural Bridge, where Pine Creek 

escapes past an obstructing teiTace of travertine, partly by a naiTow gorge of wild beauty 

and partly through a lofty natural tunnel 

under the calcareous mass, the nearly horizontal Paleozoic limestones and the basal 

Cambrian sandstone (Tapeats ~) are exposed 

on the east side of the stream, which has cut 

through them into the granite. On the west 

side of the creek is a precipitous slope, 400 to 

500 feet high, in which are exposed coarse red 

granite, overlain by a coarse granitic conglomerate, with bowlders as much as 2 feet in diameter, which in turn is overlain by hard 

cross-bedded reddish quartzite with layers of 

conglomerate. These beds dip about northnorthwest at an angle estimated at 55°, and 

are disturbed by faulting. The general relations of the beds at Natural Bridge are diaE. 

monadnock on a surface so nearly worn down 

to a plain as that over which the arenaceous 

deposits of the Cambrian sea were spread for 

thousands of square miles, it is still more difficult to account in any other way for this 

island-like mass of indurated tilted strata surrounded by dissimilar, nearly horizontal, and 

apparently younger beds. :Moreover, these 

older beds are much more resistant than the 

granite, and the fact that here and there eminences of hard rock projected above the general level of the vast pre-Tonto floor and were 

not finally buried until long after the deposition of the Tapeats sandstone is visibly evident in the walls of the Grand Canyon. 

Natural Bridge is one of the f~w places in 

the region where good accommodations can 

. be had for man and beast, and the locality 

would well repay more careful study than 

w. 

FIGURE H.-Diagrammatic section across Pine Creek at Natural Bridge, Ariz. 

grammatically indicated in the rough sketch could be given to it in the course of the hasty 

of figure 14. The coarse conglomerate and reconnaissance made in 1912. 

arkose conglomeratic quartzite ori the west 

side of the creek at Natural Bridge are ap- JEROME GEOLOGIC SECTION, WITH NOTES ON 

Parently older than the sandstone and over- STRATIGRAPHY BETWEEN PAYSON AND 

JEROME. lying limestone on the east s~de and are part 

of a steep ridge that rose above the general 

level of the granitic surface upon which the 

basal sandstone (Tapeats ~) accumulated. This 

ridge can be traced in a north-northeasterly 

direction from Natural Bridge for about 4 

miles, to a point east of Pine, where it passes 

under the horizontal strata of the plateau. 

About 2-! miles southeast of Pine, on the road 

to Payson, the nearly horizontal limestones 

above the Cambrian sandstone abut unconformably against the slope of this old ridge 

and locally contain angular fragments of the 

older quartzite. 

While it is difficult to understand the survival of a small sharp ridge as an isolated 

The geologic column given in Plate XXV as 

the Jerome section is really a composite, only 

the part below the Supai formation having 

been measured at Jerome. The higher beds, 

however, are well exposed in the escarpment 

of the plateau a few miles north of the town 

and along the route from Payson to Camp 

Verde by way of Fossil Creek. The thicknesses given for the Supai and Coconino formations were obtained by rough aneroid measurements on Fossil Creek and at the head of 

Pine Creek. 

An excellent section of the lower part of the 

local geologic column is exposed where the 

road from Payson to Pine crosses East Verde 
160 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

River. At the base is coarse red granite. 

Upon this rests horizontally 80 feet of dull 

red-brown cross-bedded pebbly sandstone. 

Cliff faces show some irregular horizontal · 

lamination but no distinct divisional planes, 

and the whole forms a single thick bed. Few 

of the included pebbles are over an inch 

in diameter. Overlying the massive bed are 

thinner-bedded pebbly sandstones grading upward through a thin layer of shale to limestone. The thinner sandstone beds have a 

thickness of 30 feet, making the total thickness of the basal sandstone 110 feet. As will 

be shown later, there can be no reasonable 

doubt of the identity of this sandstone :with 

the Tapeats ("Tonto") sandstone of the Grand 

Canyon section. 

The following section of the overlying limestone was measured by aneroid a short distance west of the river, where the limestone 

is capped by Tertiary or Quaternary basalt. 

The numbers correspond to those used in the 

Jerome section on Plate XXV (p. 136). 

Section of limestone near East Verde River. 

Basalt. 

8. Rather thin-bedded, in part :flaggy light-gray 

compact li~Il;estone, with a few thin beds of 

sandstone near top ......................... . 

7. Pink and gray sandy limestone ................ . 

Feet. 

130 

50 

ment of the Coconino sandstone at the he.ad of 

Pine Creek showed that the Coconino is at 

least 500 feet thick. It is a fine-grained, 

remarkably homogeneous, and rather soft 

sandstone, whose constituent quartz grains 

sparkle brilliantly in the sunlight. The color 

generally is pale buff to nearly white, but it 

weathers in more or less rusty tints near the 

base. Cross- bedding as a rule is more conspicuous than bedding and the rock splits 

more readily along the oblique laminations 

than it does parallel with the true bedding. 

About 6 miles west of Pine the mail trail 

between Payson and Camp Verde crosses the 

canyon of Fossil Creek 1 and affords a fairly 

good section of the Supai formation, which 

here consists chiefly of bright-red friable, very 

fine grained calcareous and gypsiferous sandstones, with a few beds of soft light-gray sandy 

limestone. One bed of such limestone, about 

20 feet thick, is well exposed on the trail about 

50 feet .below the east rim of the canyon and 

is regarded as the topmost bed of the Supai. 

About 800 feet below this bed is a layer of 

gray limestone conglomerate, about 12 feet 

thick, with pebbles of limestone as much as 

2 inches in diameter. A seam of very impure 

lignite, reported to be in places 20 inches thick, 

lies just under this conglomerate and is said by 

prospectors to be accompanied by some native 

6. Hard, compact gray limestone in beds 2 to 3 feet 

thick ....................................... . 

5. Red shale, with bed of laminated gray quartzite, 

2 to 3 feet thick at the top ................. .. 

4. Thin-bedded gray limestone. For 25 or 30 feet 

above the Tapeats sandstone this is :flaggy and 

somewhat sandy·. Grades upward into comcopper. The barometric readings on this sec50 tion gave a thickness of about 1,250 feet for 

20 the Supai formation, but this is probably a 

little high, and an estimated thickness of 

pact, hard light-gray and pink limestone ..... . 100 

Tapeats sandstone. 350 

No fossils were found in these beds, but the 

limestones are probably, i::1 part at least, 

Devonian. It is to be noted that the Bright 

Angel ("Tonto") shale of the Grand Canyon 

is not represented on the East Verde. 

The beds underlying the little alluvial valley 

at Pine appears to belong to the lower part of 

the Supai, and higher strata of the same formation crop out as a broad rosy band along the 

cliffs north and east of the viltage. As a rule 

this strjp of bright color blends rather indefinitely into the buff tint of the overlying Cocoruno sandstone, which is the cliffmaker of this 

part of the plateau edge. An aneroid measure1,000 feet is used in the Jerome section (Pl. 

XXV). The Supai beds are locally very soft 

and generally form steep ruddy slopes under 

the pale-buff cliffs of the Coconino sandstone. 

The distinction between the two formations, 

as seen in cliff faces, is not sharp, as there are 

some soft reddish beds above the 20-foot gray 

limestone. Likewise at the base there is some 

gradation of the red beds into the rather thin 

bedded gray limestones, presumably Redwall, 

exposed in the bottom of Fossil Canyon. 

Between Fossil Creek and Camp Verde tha 

sediinen tary rocks are buried under heavy 

flows of basalt, with intercalated layers of 

tuff, which apparently are younger than the 

extensive lacust~e deposits, consisting of 

1 This creek owe~ its name to the incrusting action of some copious 

springs which, after building up a huge terrace of travertine, now issue 

from the base of the mass, on the edge of the stream. 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 161 

gypsiferous clays, limestone, gypsum, and salt 

and probably over 1,000 feet thick, that fiU 

this part of the Verde Valley. 

The town of Jerome is west of and . about 

1,500 feet above Verde River, at the north end 

of a short range known as the Black Hills. 

The prospect northeast from Jerome probably 

surpasses in beauty and geologic interest anything else to be seen in Arizona, except the 

unrivaled Grand Canyon. From 4 to 6 miles 

distant, across a belt of relatively low hills 

whose pale hue proclaims the Redwall limestone, meanders the Verde with its narrow 

fringe of trees and green fields. Beyond the 

river, 15 miles away, is the great scarp of 

the plateau, here thrusting a bold promontory 

into the valley, there retreating in some 

shadowy recess where a creek has cut back into 

the table-land, and glowing along its entire 

front with the ruddy warmth of the Supai, 

which shades upward into the creamy tints of 

the Coconino sandstone and downward in to 

the whiteness of the Redwall. Finally, 50 

miles away, beyond the pine forest whose 

fringe darkens the top of the cliff, the even 

sky line of the plateau is boldly surmounted by 

the volcanic mass of the San Francisco Mountains, upon whose crest the snow yields but 

slowly to the heat of summer. Nor is it necessary to look to these distant peaks for evidence 

of volcanic activity in recent geologic time. 

Dark flows of basalt, at various levels, cap parts 

of the plateau and outlying mesas, much 

nearer at hand, and only a few miles north of 

Jerome, Verde River has barely succeeded in 

cutting through a lava stream that usurped its 

channel. 

The rocks of the Black Hills have undergone 

some of the deformation which is so characteristic a feature of the mountain region and which 

gives it a structure and topography so different 

from that of the plateau, here in plain sight 

for comparison. The most conspicuous element of the structure near Jerome is a fault 

that strikes N. 30° W. and dips about 60° NE. 

The dislocation is of the kind olassed as normal, and the throw at Jerome is roughly estimated at about 1,300 feet. The result of the 

movement has been to elevate the Black Hills. 

relatively to the plateau country, to expose the 

pre-Camb::-i~n schists southwest of the!Sfault, 

and incidentally to bring to light the great 

body of copper ore now worked by the United 

Verde Copper Co. 

Resting upon the schists on the hillside just 

west of the United Verde mine is the Tapeats 

sandstone, 75 to 80 feet thick. It is locally 

a very dark red cross-bedded pebbly sandstone 

in which the pebbles, for the most part collected into lenticular layers, are rarely over 1 

inch and mostly under half an inch in diameter. 

The dark rusty hue of the sandstone is probably 

due to ferruginous gossan material, derived 

from the pre-Cambrian pyritic deposits in the 

schist. 

Conformably above the sandstone are lightyellowish, very compact limestones in beds 

from 2 to 3 feet thick and containing only obscure traces of fossils. These beds resemble the 

compact limestones of the lower part of the 

Martin limestone at Ray. This part of the 

formation, about 150 feet thick, is overlain by 

darker-gray limestones, some of which are 

sandy. Fossils are fairly abundant in these 

strata, but are as a rule poorly preserved and 

extremely difficult to collect. About 350 feet 

above the base of the limestone a light-gray 

bed about 5 feet thick, sandy in its lower part, 

but grading upward into a purer and more 

compact limestone, carries abundant small 

poorly preserved ·shells near its base and 

corals in its upper part. Fossils collected 

from this bed and those just above it were 

submitted to Dr. E. M. Kindle, who has identified the following species: 

Aulopora sp. undet. 

Zaphrentis sp. undet. 

Camarotrechia sp. undet. 

Spirifer orestes. 

Cyrtia cyrtiniformis. 

Bellerophon mrera. 

Mr. Kindle writes: "These species represent 

an Upper Devonian fauna of the same general 

facies as that previously collected by you at 

various points in Arizona." In other words, 

it is the faUiia of the Martin limestone. The 

total thiclmess of the beds provisionally assigned to the Devonian at Jerome is about 500 

feet. Of course there is a possibility that the 

lower compact limestones, from which no fossils were obtained, may be older than Devonian. There are no beds present in the local 

section, however, that can be referred to the 

Bright Angel shale. 
162 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Above the comparatively thin-bedded and 

impure Devonian limestone are thicker beds of 

white limestone, much of which is granular 

and contains abundant fragments of crinoid 

stems. This limestone is about 250 feet thick 

near Jerome. Fossils collected from it were 

referred to G. H. Girty, who lists the following: 

Zaphrentis sp. 

Schuchertella aff. S. chemungensis Conrad. 

Schizophoria swallowi Hall. 

Chonetes illinoisensis Worthen. 

Productus burlingtonensis Ha~l. 

A vonia arcuata Hall. 

Pustula aff. P. scabricula Martin. 

Camarotmchia sp. 

Spirifer centronatus Winchell. 

Composita humilis Girty? 

Euomphalus sp. 

Bellerophon sp. 

He states that the horizon is clearly lower 

Mississippian and that the fauna shows close 

affinities with the Burlington, especially with 

the lower Burlington. This is unquestionably 

the Redwall limestone. The two lithologic 

divisions noted by Lee farther northwest are 

not apparent at Jerome, unless the beds here 

grouped with the Devonian correspond to 

the lower, thin-bedded part of the Redwall -as 

described by Lee.1 No evidence was obtained 

at Jerome to indicate that any of the Redwall 

limestone is as young as the Pennsylvanian. 

In the Black Hills, the Redwall limestone is 

overlain by the red Supai beds which in turn 

are capped by basalt and are not present in 

full thickness. 

Near the mouth of Sycamore Creek, .8 miles 

north of Jerome, fully 450 feet of limestone 

is-exposed below the ·Supai. At the base of 

the Supai is a limestone conglomerate 2 to 3 

feet thick in -whic4 the pebbles are generally less than 2 inches in_ diameter. Layers 

of similar conglomerate also occur a little 

higher in the formatipn. At this locality the 

lower 700 feet of the Supai consists chiefly of 

fine-grained cross-bedded sandstone in beds 

less than 6 feet thick, with a smaller proportion 

of deep red shale. The general color is not 

brilliant, and some of the sandstone beds 

incline to a tawny hue. The upper beds of 

this division of the formation are fairly massive 

and form an outer bench in the plateau 

escarpment at this locality. Overlying them 

1 Lee, W. T., Geologic reconnaissance of a part of we::;tem Arizona: 

U. S. Geol. Survey Bull. 352, pp. 15-16, 1908. 

; . 

and under the Coconino sandstone are apparently softer beds of much brighter red, with 

an estimated thickness of 200 to 300 feet. As 

seen through field glasses at a distance of 2 or 3 

miles they show conspicuous cross-bedding 

and appear to grade upward with no sharp 

break into the Coconino sandstone. 

Gilbert 1 has given a section at a looality 

described as '' 15 miles southeast of Bill Williams Mountain." This apparently was measured on Sycamore Creek, some miles above its 

mouth. The section as given indicates the 

presence of 400 feet of Redwalllimestone (base 

not seen), 600 feet of Supai (that is, 400 feet of 

''alternating fine-grained limestones and calcareous red and yellow sandstones," overlain 

by 200 feet of "friable red sandstone"), 700 feet 

of Coconino sandstone, and 335 feet of Kaibab 

limestone. overlain by basalt. 

GRAND CANYON GEOLOGIC SECTIONS. 

The general character and succession of beds 

in the Grand Canyon are too well known to 

geologists to require more than very brief 

description here. 

_ .In the section given by Gilbert 2 for the 

mouth of the Grand Canyon the Tonto group, 

from the base up, is made to include the 

"Tonto sandstone" (now the Tapeats sandstone), 80 feet; the "Tonto shale" (now the 

Bright Angel shale), 600 feet; and the "marbled limestone" (now the Muav limestone 3) 75 

feet. Some uncertainty appears to exist as to 

the limits of the Muav limestone. Lee,4 in his 

section measured a few miles west of the mouth 

of the Grand Canyon, describes the Tapeats 

sandstone as overlain by ''about 600 feet of 

yellowish-green arenaceous shale," succeeded 

by the Redwall. In the Shinumo quadrangle 

Noble 5 noted 450 to 4 7 5 feet of Mua v limestone 

and only 25 to 375 feet of Bright .Arigel shale. 

He has separated as the Muav limestone beds 

that Gilbert and other observers considered to 

be part of the "Tonto shale," his Muav being 

the upper calcareous portion of the old ''Tonto 

shale." 

1 Gilbert, G. K., U.S. Geog. Surveys W.100thMer. Rept., vol.3,p.163, 

1875. 

2 Idem, pp. 184, 196. 

a Noble, L. F., The Shinumo quadrangle, Grand Canyon district, 

Ariz.: U.S. Gaol. Survey Bull. 549,p. 64,1914. · 

• Lee: W. T., Geologic reconnaissance of a part of western Arizoi18j 

U.S. Geol. Survey Bull. 352, p. 15, 1908. 

sOp. cit., pl. 9. 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 163 

In the Kanab Valley, northwest of the 

Shinumo area, according to Walcott, 1 there is 

235 feet of "massive mottled limestone with 

50 feet of sandstone at base" unconformably 

below the Devonian and above the "Tonto 

Primordial." This is probably the Muav 

limestone. In the portion of the canyon between the Bright Angel and Hance trails the 

Muav limestone, according to my own observations, is not conspicuously different, either 

in topographic expression or lithology, from 

the l)llderlying shaly beds, and although the 

impure calcareous strata near the top of the 

Tonto group were not measured, they did not 

appear to be nearly so thick as was stated by 

Noble for the Muav limestone in the Shinumo 

quadrangle. Similarly Frach 2 in his Congress 

Canyon section gives the Tonto group a thickness of 7 49 feet, of which the lower 290 feet is 

sandstone, leaving 459 feet for the generally 

snuff-colored shaly beds. He mentions the 

presence of some impure limestone in the upper 

part of the "upper Tonto," probably the Muav 

limestone. 

The section given for the Kaibab district of 

the Grand Canyon region in Plate XXV (p. 136) 

is practically that given by Noble,3 the latest 

and probably the most accurate of the published sections of the Grand Canyon strata. 

At the base of the stratigraphic column is the 

great wedge and smaller remnants of Algonkian beds named by Walcott 4 the Unkar and 

Chuar "terranes" and more recently described 

in greater detail by Noble. 5 The rocks composing the Unkar and Chuar groups include 

conglomerates, sandstones, shales, and limestones and are, owing to their variety, not 

easily characterized in brief. They are essentially fluviatile (deltaic) or shallow-water deposits, prevailingly red in the Unkar group and 

of more diversity of hue in the Chuar group. 

Lithologically the rocks of both groups have 

little resemblance to the lower formations of 

1 Walcott, C. D., The Permian and other Paleozoic groups of the Kanab 

Valley, Ariz.: Am. Jour. Sci., 3d ser., vol. 20, p. 222, 1880. 

~Frech, F., Section in Congress Canyon opposite Point Sublime: 

5• Cong. geol. internat., Compt. rend., p. 479, 1893. Congress Canyon is 

apparently what is known as Red Canyon, through which runs the old 

Hance trail, and is far east of Point Sublime. 

a Op. cit., pl. 9. 

4 Walcott, C. D.; Algonkian rocks of the Grand Canyon of the Colorado: 

Jour. Geology, vol. 3, pp. 312-330, 1895. (Gives references to his earlier 

papers on same subject.) 

Q Noble, L. F., op. cit., pp. 40-53. 

the Globe-Ray and other sections to the 

south. 

The Tapeats sandstone, 285 feet in maximum 

thickness, is generally a rather coarse crossbedded sandstone grading here and there into 

a pebbly grit. Lenticular layers of yellowish 

well-rounded qu~rtz pebbles, the largest the 

size of peas, are very common. In contrast 

with the quartzites of the Algonkian, which 

commonly show conspicuous vertical jointing, 

the cliff faces of the Tapeats sandstone are 

characterized by a nearly horizontal banding, 

due to alternations of coarse and fine material. 

The usual color is buff, but in places this 

shades into dull red or maroon. 

The Bright Angel shale, 375 feet thick, consists of fissile shales, for the most part micaceous, associated with thin beds of micaceous 

sandstone and impure limestones. The prevailing color is greenish yellow, and the formation generally weathers to a smooth slope. It 

has been carefully described by Noble.1 Fossils 

from this formation, including some wellpreserved trilobites obtained in 1911 near the 

Bright Angel trail, have been pronounced 

Middle Cambrian by Dr. C. D. Walcott. 

The Muav limestone, according to Noble,2 is 

the predominantly calcareous upper part of 

the Tonto group and is 475 feet in maximum 

thickness. Since Bulletin 549 was written he 

has found fossils in the Muav limestone which, 

according to Edwin Kirk, of the United States 

Geological Survey, are of Middle or Upper 

Cambrian age. 3 

The Devonian Temple Butte limestone, 100 

feet in m~ximum thickness, is in many places 

absent. Recent work of Mr. Noble, not yet 

published, supplies many details of its occurrence and of the unconformities between it and 

the overlying Redwalllimestone and the underlying Muav limestone. 

The massive Redwalllimestone, from 600 to 

700 feet thick, is overlain by the relatively 

thin-bedded red shales and sandstones of the 

Supai, 1,250 to 1,400 feet thick, followed by 

cross-bedded Coconino sandstone, 250 to 350 

feet thick, and the pale-gray Kaibab limestone, 

400 to 600 feet thick, containing Pennsylvanian 

fossils and extending to the brink of the canyon. 

1 Noble, L. F., op. cit., pp. 62-64. 

2 Idem, pp. 64-65. 

a Personal communication from L. F. Noble. 
164 ~HORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

CORRELATION. 

In the comparison of the ten columnar sections shown in Plate XXV (p. 136) the most 

obvious stratigraphic plane of reference is the 

great unconformity at the base of the Cambrian. Another zone useful for correlation is 

that of the Devonian beds, which, in a northsouth belt extending through central Arizona, 

are made up persistently of limestone, are 

generally of moderate total thiclmess compared with the Cambrian and Carboniferous 

formations, and contain a characteristic fossil 

fauna, that of the Martin limestone of the 

Bisbee section. To the east, in the CliftonMorenci region, the Devonian beds consist 

chiefly of shale, this probably representing a 

gradation into the Percha shale of New Mexico. 

In the Grand Canyon region pre-Redwall 

erosion has in some places removed the Devonian beds, but they are present in a sufficient 

number of localities in the canyon, as has been 

shown by Noble,! to establish their lithologic 

character and tlieir place in the local section. 

At Jerome the Devonian limestone as represented in the columnar section of Plate XXV 

is thicker than in the more carefully studied 

sections to the south. Further examination 

may show that some of the lower beds provisionally included in the Devonian of the 

Jerome section belong to an older period. 

It is with the correlation of the part of the 

geologic sections between the Devonian and 

the unconformity at the base of the Cambrian 

that the present paper is chiefly concerned. 

Comparison will first be made of this part of 

the Globe-Ray section with the corresponding 

part of the Bisbee section. 

The lower parts of these two sections show 

decided differences. The Globe-Ray section 

includes the Scanlan conglomerate, the Pioneer 

shale, the Barnes conglomerate, the Dripping 

Spring quartzite, the Mescal limestone, and 

the Troy quartzite, with an aggregate thiclmess 

of 1,200 to 1,300 feet. At Bisbee there are 

the Bolsa quartzite, with some basal conglomerate, overlain by the Abrigo limestone, and 

the aggegate thiclmess is about 1,200 feet. 

In a general way the Bisbee Cambrian section 

resembles the Grand Canyon section, and it is 

not difficult to imagine the Bolsa quartzite as 

equivalent to the Tapeats (formerly the Tonto) 

1 Noble, L. F., paper in preparation for publication. 

sandstone and the Abrigo limestone as t:quivalent to the Bright Angel shale and Muav limestone (formerly both included in the "Tonto 

shale"). The probability of this exact equivalence is lessened, however, by the fact that the 

Bisbee and Grand Canyon sections are separated areally by the Globe-Ray section of a 

different type. _ 

Fossils, considered by Dr. Charles D. Walcott to be Middle Cambrian, were found in the 

Abrigo limestone, but the supposed Cambrian 

portion of the Globe-Ray section has yielded 

no determinable fossil remains. Correlation 

by means of paleontology is therefore at present out of the questjon. Lithologically th~ 

Abrigo limestone and the Mescallimes~one a~e 

in part identical, and as the beds shoWing t~ 

identity are of unusual character and marntain this character over large areas, the conclusion that the Abrigo and Mescal limestone 

are probably the same appears to be ~?st 

nearly in accord with the facts. The stnking 

similarity of the peculiar cherty limestone of 

the Abrigo and Mescal is shown by a comparison of Plates XXVIII and XXX. 

If as is likely, these two limestones are ' • 0 0 identical, then the Bolsa quartzite 1s eqmvalent to the Dripping Spring quartzite or to the 

Dripping Spring . quartzite, Barnes conglomerate, Pioneer shale, and Scanlan conglomerate. 

In spite of metamorphism which has transformed the Pioneer shale locally to mica schist, 

the four formations just mentioned are recognizable in the Santa Catalina Range. Evidently, therefore, considerable change takes 

place within the 50 or 60 miles intervening between the Santa Ca.talina Range and Tombstone where the section is of the Bisbee type. ' If the . Abrigo and Mescal limestones are the 

same, then the Troy quartzite, about 400 feet 

thick in the Globe-Ray region, is represented 

at Bisbee by a bed of white quartzite, 8 feet 

thick, at the top of the Abrigo.1 . 

The Clifton section is much like that at 

Bisbee. The Coronado quartzite is in all 

probability the same as the Bolsa quartzite. 

The Longfellow limestone, from Lindgren's 

descriptions, appears to resemble the Abrigo 

limestone in many respects and is probably, in 

part at least, equivalent to it. Fossils obtained from the upper part of the Longfellow 

1 Ransome, F. L., Geology and ore deposits of the Bisbee quadrangle, 

Ariz.: U.S. Geol. Survey Prof. Paper 21, p . 32, 1904. 
SOME PALEOZOIC SECTIONS IN ARIZONA AND THEIR CORRELATION. 165 

limestone were determined by E. 0. Ulrich 

to be of Ordovician age. 1 As no fossils were 

found in the upper part of the Abrigo at Bisbee, the occurrence of the Ordovician fossils 

at Clifton does not preclude correlation of the 

two limestones. 

North of the Globe-Ray region the preDevonian units of the Ray section are all recognizable at Roosevelt and in the Sierra 

Ancha. In the southern part of that range, 

however, the development of 1,100 feet or 

more of sandstone above the :Mescal limestone makes correlation with the Troy quartzite rather uncertain. This sandstone appears 

to have the stratigraphic position of the Troy, 

but · differs in lithologic character and is 

nearly three times as thick as that formation. 

The significance of this considerable change in 

the section in so comparatively short a distance as that between Roosevelt and Aztec 

Peak is not fully understood, and it is doubtful 

whether the beds of the Sierra Ancha section 

can ever be traced continuously into those of 

the Ray-Globe section. The only chance 

would be by way of the Apache Mountains, 

and the general structure and topography of 

the region makes it almost certain that there 

are gaps of many miles in which the Troy 

quartzite or its equivalent beds are not exposed or have been removed by erosion. 

At the north end of the Sierra Ancha the section below what is supposed to be the Mescal 

limestone is not readily divisible into the units 

of the Globe-Ray section. Nevertheless it is 

believed to be more closely allied to that section than to those north of the Sierra Ancha. 

From the north end of the Sierra Ancha to 

the vicinity of Payson there is a gap of about 

15 miles in which the Paleozoic rocks are not 

present. This interval, as already described 

on page 157, is occupied by pre-Cambrian crystalline rocks and by the pre-Cambrian quartzites, shales, and conglomerates that are well 

exposed in the Mazatzal Range. If the Grand 

Canyon series (Unkar and Chuar) is represented in the Tonto region of Arizona, it is.withotit much doubt to be correlated with these 

older sedimentary beds and not, as some writers 

have suggested, with the unconformably overlying Apache group. 

The last three sections given in Plate XXV 

are sections of the practically horizontal strata 

1 U. S. Geol. Sur.rey Geol. Atlas, Clifton folio (No. 129), p. 4, 1905. 

of the Arizona Plateau and differ materially 

from those of the more disturbed rocks of the 

mountain region. This difference is strikingly 

apparent to one who, after studying the thick 

quartzitic sandstones of the Sierra Ancha, sees 

for the first time the sections near Payson, in 

which a comparatively thin basal sandstone is 

succeeded by limestones having no resemblance 

to the Mescal limestone. (Seep. 160.) There 

is apparently little change in the character of 

the beds from Payson to the vicinity of Jerome, 

and the basal sandstone is, without much 

doubt, the Tapeats sandstone ("Tonto" sandstone) of the Grand Canyon section. The 

Bright Angel shale and Muav limestone, however, have not been identified at Jerome or at 

any locality southeast of that town. 

The plateau sections differ also from those of 

the_ mountain region south of Payson in the 

development of the Carboniferous strata. In 

central and southern Arizona the Carboniferous 

is represented by great thicknesses of gray limestone that is not, as a rule, easily separable into 

Mississippian and Pennsylvanian portions. In 

the plateau sections there is a great development of sandstones and shales, and the Carboniferous deposits are divisible into the Redwall 

limestone, the Supai formation (red sandstones 

and shales), the Coconino sandstone, and the 

Kaibab limestone, named in ascending order. 

Gilbert's Canyon Creek section, while distinctly of the plateau type, indicates considerable change in character ·east of Payson. It 

shows an increase in the thickness of the Cambrian sandstone and the absence of the Devonian beds through unconformity. No unconformity was noticed between the Devonian and 

Carboniferous at Jerome, but the study given to 

this section was too hasty to warrant the assertion that none is present. 

The observations presented in this paper 

indicate that in Cambrian time a land barrier 

existed in the region now adjacent to Tonto 

Basin, between the depositional basin of central 

and southern Arizona and that now corresponding to the Arizona Plateau, or at least to that 

part of the plateau between Payson and the 

Grand Canyon. It follows that while the 

whole Apache group and· its stratigraphic equivalents in eastern and southern Arizona were 

probably deposited at about the same time as 

the beds of the Tonto group, the beds of the 

two groups were probably never continuous 

within the Tonto region of Arizona. It can not 
166 SHORTER CONTRJBUTIONS TO GENERAL GEOLOGY, 1916. 

be said that any particular sandstone or quartzite of the Apache group is identical with the 

Tapeats sandstone. 

Although the evidence from fossils is lacking, 

it appears to be fairly well established that the 

entire Apache group is Cambrian, or possibly in 

part younger, and, so far as can be seen over a 

wide region, is conformably overlain by the 

· Devonian, while in the northern parts of the 

Mazatzal Range and Sierra Ancha the Paleozoic 

beds overlie with conspicuous unconformity a 

series 9f shales, quartzites, and conglomerates 

which is probably equivalent to the Grand 

Canyon series. 

The marked difference in the Carboniferous 

sections of the two geographic provinces in 

north-central Arizona suggests that the natural 

barrier supposed to exist in Cambrian time may 

have persisted in some form, possibly as a submarine ridge, throughout the Paleozoic era.