UNITED STATES 

DEPARTMENT OF THE INTERIOR 

J. A. KRUG, Secretary 

GEOLOGICAL SURVEY 

W. E. WRATHER, Director 

\ 

CIRCULAR 16 

LATE PALEOZOIC ROCKS EXPOSED IN 

THE DUCHESNE RIVER AREA, 

DUCHESNE COUNTY, UTAH 

By 

John W. Huddle and Franklin T. McCann 

WASHINGTON 

1947 

UNITED STATES 

DEPARTMENT OF THE INTERIOR 

J. A. KRUG, Secretary 

GEOLOGICAL SURVEY 

W. E. WRATHER, Director 

CIRCULAR 16 

LATE PALEOZOIC ROCKS EXPOSED IN 

THE DUCHESNE RIVER AREA, . DUCHESNE ·COUNTY, UTAH 

By 

John W. Huddle and Franklin T. McCann 

WASHINGTON 

1947 
. IATE PALEOZOIC ROCKS EXPOSED IN THE DUCHESNE RIVER AREA, 

DUCHESNE CO:tJNTY, UTAH. 

By John W. Huddle and Franklin T. McCann 

During 1945 two field parties of the U. S. Geological Survey 

investigated the stratigraphy and structure of the pre~Tertiary 

rocks on the south slope of the Uinta Mountains in northeastern 

Utah. The work was undertaken because of the increasing interest 

in the oil and gas possibilities of the Uinta Basin, which lies 

south of the Uinta Mountains. Geologic reports on these areas 

are in preparation but it seems advisable to present at this 

time a detailed section of the lata Paleozoic rocks in the 

Duchesne River area. 

The late Paleozoic rocks in the Duchesne River were/ 

first mappPd and described by Berkey (1905, pp. 517-530), and his 

work was followed by the reports of Emmons (1907, pp. 287-302), 

and Weeks (190')7, pp. 427-448), who recognized the same general 

sequence of rocks as Berkey described but disagreed regarding the 

thicknesses and correlations given by him. Detailed sections of 

the Permian and Carb~niferous formations in the Duchesne River 

area are inciuded in two recen~ articles by J. Stewart Williams (193~, P• 98; 1943, pp. 602-605). . 

Late Paleozoic rocks are exposed in the canyon walls of 

Duchesne River and in tributary ca~ons, but only parts of the 

sequence are exposed at each place, and the section herein des.-

cribed is a composite of several outcrops. Because of the presence 

of numerous small faults a few of the thicknesses·could not be 

accurately determined. The inadequate exposures of ;r:art of the 

sequence of rocks and the presence of the small faults probably 

explain most or all the differences in thickness of certain units 

between our section and sections previously published·by others. 

On the south flank of the Uinta Mountains the beds of late 

Paleozoic limestone rest with angular unconformity on beds of 

quartzite and shale correlated with the Pine Valley quartzite or, 

where this formation is absent, on the Ophir (?) shale of 

Cambrian age (Forrester, 1937, p. 638). The Madison limestone of 

Mississippian age is about 245 'feet thick and consists mainly of 

thin-bedded, dark-gray fossiliferous'limestone; the lower part of 

the formation, 36 feet thick, consists of massive beds of dolomitic 

and sandy limestone. Typical ~adison limestone faunules were 

identified by James Steele Williams from beds that crop out along 

the North Fork of Duchesne River. A limestone formation about 

600-650 feet thick; immediately overlying tne Madison limestone, 

is herein tentatively correlated with the Deseret limestone of the 

2 
1-

• 

UTAH 

To Duchesne 

SK'ETCH MAP I OF THE O,UCHESNE RIVER AREA, UTAH 

SHOWING THE LOCATION:'' OF MEASURED SECTIONS 

2 ;3 4 5 
Formation Member Section 

(/) 

IJ.I 

a: 

C/)IJ.I 

(/) 

z 

Woodside 

shale 

Park City 

formation 

~ . 0 w Block shale 

Upper 

MiddiA 

Lower :·:)"'\·:·:::·:· =:l, 

.-.~ ~·::·:·.:.:. ::::~ ::: 

~-

Lower -------- 1 ·~ I t:. I 

Feet Character of rocks 

Reddish- brown s iUs tone 

00 150 Sandy dolomitic " 

40 Block ohosohotic shale 

950? 

to 

1,600 

205 

242 

00-250 

B r e c c i a, sa n d stone, and 

limestone 

M.ossive, friable, very 

fine grained sandstone 

and sandy dolomitic 

limestone 

Reddish-brown sandstone 

and siltst.one 

Gray cherty I i me stone, 

sandstone, and shale 

Block shale and thin 

limestone beds 

a:: ·::::"*:~·:i:{~: 

m IJ.I Humbug ;;;;;: :::'\~}~ Breccia, sandstone, and 

U>~~f=o~r~m~a~t~io~n~----~-J~~Y~t~~tf~t@~~WlJH] __ 

3

_

6

_

0 

a: ::': :!:::f/:::?::J:: __ ~·-I-im_e_s~t-on_e----~----------__j z / / ~ ~ 1~ I 

<t I /t> I 

a.. Deseret "'" I> 1 I> 1 

o ~ li m e s to n e 1/ ~ I ~ I I I 16oo-s 50 

(f) I I I 

1 J 

Brown to gray, medium to 

thick-bedded 'limestone 

and do1omitlc limestone 

(f)~------------------~~~._1~1~+-----~~------------------------~ (/) Modi son 

:E limestone 

t-::~=------t-P-.-.n-e_V_a_l_le-y-----h..~08/;Bq 

~85· ·-~·:+·:·:~:::~: ::~-:-:: quartzite : ·:··.~·:··.'·?: ~:~.:: ·.~ ·. ·:~. :~·:.(): ··o:: :o: :.c,;: :c,: :o: · .. ~ .. :o~ · :·~ . .'·~ .. ·o· 

245 

375+ 

Thin'l'bedded, gray, dense 

II me stone 

Massive sandstone and 

cong I om e rate 

LATE PALEOZOIC ROCKS EXPOSED IN DUCHESNE RIVER AREA, UTAH 
wasatch (Baker, oral conun~ication) and Cquirrh Mountains 

(Gilluly, 1932J pp. 25-26)~ These beds in the Duchesne River 

area were included in the ~::ad:tson limestone in ear}.ier reports. 

The . forna tion is d isting,.liBhr:Jd f:::- o·:n the Jv1adis on :im.eston·e by its 

thicker bedding_, brown co:Lo:':, gre9-ter au~nbe:r of beds of dolomitic 

limestones, and by the cha:cact-e-r of its coral fauna. The contact between the Madison and Deeeret limestone: however, is not 

everywhere easily dist:5.nguir-;hatle. · Fossils collected f:com the 

Deseret limestone were examined by James Steele Williams, who 

reported (personal communication) that though not definitely 

diagnostic, they probably are of post-!~disori age, as is the 

Deseret. 

A sequence of limestone and sandstone breccia about 360 

feet thick overlies the Deseret limestone. Though no fossils 

were found in this formation, it is considered to be equivalent 

to the Humbug formation of the 1~satch and Oquirrh Mountains on 

the basis of similar litho logic character and s'tra t1g:ra phic 

position" The Hu:nbug forrr.ation of the Oquirrh Hountains was 

cor-related by Gillu:t_y ( 1932, pp. 26..-29) with part of the Brazer 

limento!:-Je of sm,_thea~tern Idaho. Overlying t::1e H•.1.'nbug forma.tion 

is a b }ac; k shale ~::..tll t a. !Jout 200-250 feet; :,td.ck, -that, :may be 

equivalent to par\j o:f the Manning C~nyor1 rJh.:tle of -~he ~Vasatch 

(Baker~ ora_:_ cor:rwn.mication) and Cquirrh }tcurlta:_!!S C..rilluly, 1932, 

pp .. 31-~34). The foTma·tiiun is _f;B.rtly exposed :in mudflows and 

landslides a::_e;ng uches~e River Canyon and .:.s ()et·Ler exposed in 

Soapstone Bas·tn and on the headwatc:~c o£' Blind Stream. Fos·sils 

collected from the black shale and e lso fr·om a limestone bed 

near the top of the fonr.ation a:re ccnsj_dered by James Steele 

Williams (personal ccnununication) and Helen Duncan as of post-

~fadison Mississippian age, equivalent to part of the Brazer 

limestone" 

The rocks in an interval, about 450 feet thick, irr~ediately 

above the black shale .J are assigned to the Morgan forrration of 

the Penns;y<lvanj_an serj_es and are divided in to a lowe:c limestone · 

member and an uppel· El.S.nds cone member~ Tl1e lower mernbe:::-, which 

is abcn:o.L ~..'.u feat chick~ :t.C! COIH!)OSed chiefTy oi' limestone, The 

mega.fo.::si~:c cc·: lected from th'2 lower· member wh1le not c..;..agn.GtJtic_ 

are eonsJ.dered m.~obabJ~r of ea;··;v Penns~.--lvan]i=l.n age by James 

Steele W:i.~::_-_,dm:-; .. (p·arRott3.l c:,mmutJJ.cat.io;). Thom~~.son (19~5, p. 24) also 

regards them as early Pennsylvanian in age. Tbe upper member o£ 

the !v!o;:·gan fo:':'matl~X1 :..s al;~1.1t ?.05 feet thick and consist.<? chiefly 

of sand~r~one .. It is dia t.:i.tti?:UJ~bed bv its r•ed-brown colo:c. and 

the c·.;Ptac.;~;j lVith the 8VerJ.ylug Waber-" sandstone is grada ti.onal. 

No fossils we·ce found in the upper member of the ~~fo:cgan formation, bui:. it is considered early Pennsylvanian in age. 

The Weber sandstone was not satisfactorily measured in the 

Duchesne River area because the uppermoct and iowermost, parts of 

5 
the formation are poorly exposed and the beds are cut by many 

small faults .. The thickness of the formation is probably about 

1,500 to 1,600 feet in Rhoades Canyon, which is about 4 miles 

northwest of Stockmore Ranger Station;· about 950 feet immediately 

west of Stockmore Ranger Station; and abou~ 1,200 feet in the 

west wall of Duchesne Ri·ver canyon about l;i miles north of Stockmore Ranger Station. The differences in the' thickness measured 

at these pla.ces may be real or they may be due to faulting. The 

formation consists largely of very fine grained sandstone, but 

includes a few beds of limestone interbedded with the sandstone 

throughout the formation. , 

Three members of the Park City formation were recognized in 

the Duchesne River area; they are a lower member of sandstone and 

limestone breccia, a middle member of black phosphatic shale, and 

an upper member of dolomitic limestone. all three members are 

here indicated, for convenience, as Permian, although the lower 

part of the typical Fark City formation is roferred to the 

Pennsylvanian. The lower member is about 270 feet thick and consists largely of sandstone and limestone breccia, but includes 

some limestone beds. A few poorly preserved fossils that were 

collected from the lower member in sec. 11, r. 1 N., R. 9 W., 

about a mile northwest of Johnson's Mill, were considered not 

certainly diagnostic.by James Steele Williams (personal communication), but were thought to resemble the local Permian facies 

more than anv of the local Pennsvlvanian facies. On Blind Stream 

the middle m~mber of black phosphatic shale is 40 feet thick and 

the upper member of dolomitic limestone is l00-150.feet thick. 

The upper member is unconformably overlain by the Woodside shale 

of the Triassic svstem and variations in the thickness of the 

upper member appear to be the result of erosion prior to the _ deposition of the ':Voodside shale. The limestono, chert, and siltstone sequence, which is questionably referred to the Woodside 

shale in the section described below, may·really belong in the 

upper member of the Park City formation. 

6 
SECTION OF PALEOZOIC ROCKS ll~ DUCHESKE RIVER ARFA 

TRIASSIC(?) ~3YSTEM 

Woodside shale (?) 

Measured along Forest Service trail up the east wall of 

Blind stream in sec. 14, T. 1 N., R. 8 W~, about Bi 

miles northwest of Tabiona, Utah~ (Locality No. 1 on 

sketch rna p) 

Limestone and chert, loose blocks of gray limestone 

and sugary white chert capping the ridge • • • • • • 

Siltstone, calcareous, red-brown, laminated and thin 

Thickness 

(feet) 

bedded; thickness estL~ated ..••.. ~ • • • 25o0 

PERMD.t.N SYSTEM 

Park City formation 

Upper member 

Limestone and chert, brown, weathering light-..brown; 

crystalline, sandy limestone containing abv.ndant white 

and gray, dense, chert nodules and lenses .' . • . • • 5.5 

Sandstone, light gray, fine grained, calcareous, and 

thin bedded • • • • • 1.0 

Concealed • ~ • • . . • . . . . 

Limestone, dolomitic, light gray, weathering light-buff, 

thin bedded; contains considerable white chert in 

large rl)9.sses o • • • • • • • • • • • • • • • • • 10. 0 

Limestone, dolomitic; light gray, weathering light-buff; 

finely crystalline, thick bedded; contains many small 

chert nodules and geodes, silicified fossils, especially Ambocoelia and Dielasma which are abundant 5 to 15 

feet above the base •••••••. n • 0 • 0 • • • • 39.0 

Limestone, dolomitic; light-gray and greenish-gray, 

weathering buff to light-brown; finely crystalline, 

porous with calcite vugs; contains light-gray and brown, 

dense, chert nodules and fragments of phosphatic 

brachiopods, principally Orbiculoidea; bedding is thin, 

ranging in thickness from 0.3 to 1.0 foot • • • • • • 39.0 

7 
Siltstone, cherty, light-gray and brown, weathering 

yellow-brown, slightly calcareous; in thin irregular 

beds, cohtains abundant dense' gray chert, black 

phosphatic oolites and pellets in thin beds and 

Thickness 

(feet) 

len>3es • • • • • • • • • • • • • • • • 5. ?_ 

Total thickness of upper member 

Middle member 

Shale, greenish-gray; contains streaks of black phosphatic pellets and oolites and gray limestone 

104.2 

nodules • . • • • • • • • . • • • . • • • • . • • . • 3. 3 

Limestone, light greenish-gray, weathering light yel~ow-brown, dense, thin wavy beds; contains some 

dense gray c~ert grading upn.ard into the overlying 

sha .. le . . . . . . . . . . . . . . . . . . : . . ~ . . 2. 5 

Shale, greenish-gray soft clay shale; contains streaks. 

of black phosphatic oolites and a O.?~foot bed of 

dense brown dolomitic limestone 3 feet below the top. ?.0 

Limestone, .dolomitic, cherty, dense; light gray-brown, 

weathering light-gray; contains very thin irregular 

beds and many dense gray chert nodules • • • • • • • 4.5 

Shale, black, hard, breaking to irregular chips, calcareous in part; contains many black geodes with a 

siliceous rind and calcite-filled cavity • • • • • • 16.5 

Black shale and light-brown dense dolo~itic limestone; 

contains some black phosphatic pellets and oolites • 2.5 

Sandstone, dark-brown, weathering brown; fine to 

medium, subangular to subrounded grains, scattered 

pebbles of quartzite 4 to 8 mm. in diameter in the 

lower foot and black .phosphatic nodules and pellets 

throughout; calcareous, massive, with numerous calcite 

vugs in the upper f oct . • • • . . 4 • 5 

Total thickness of middle member • . 40.8 

Lower member 

8 
Measured on the point southwest of Stockmore Ranger 

station at the junction of West Fork with the Duchesne 

River (Stockmore Ranger station is in the southeast 

corner of sec. 19, T. 1 N., R. 8 W.) (Locality No. 2 

on sketch map) 

Sandstone, weathering buff, very fine grained, massive, 

calcareous, porous, with ·10 feet of breccia at the 

Thickness 

(feet) 

'base •••••.•.•• ·'·............ 33.0 

Sandstone; white, weathering bUff, verJ fine 

grained, calcareous, porous, thin bedded; contains 

dense white chert nodules and quartz geodes. • • • • 22.0 

Limestone, cherty, light-gray, weathering medium-gray; 

dense to finely crystalline; silty and sandy in thin 

beds 0.2 to 0.5 foot thick; nodules and lenses of 

dense gray and white chert form about 30 ·percent of 

the rock • • • • • • • • • • • • • • • • • 15.0 

Limestone, sandy in the lower part; light-gray to 

dark-gray; dense, in beds less tQ8n 1 foot thick • • 10.0 

Sandstone, gray, weathering brown, very fine grained, 

well cemented with calcite, thin bedded, breaking 

into blocks on weathering • • • • • • • • • • • • • • 2?.5 

Limestone, light-gray, coarsely crystalline at the 

base, becoming dense above; thin to medium beds, 1 to 

3 feet thick, containing lenses and fingers of yellowweathering sandstone breccia. • • • • • • • • • • • • 19.0 

Sandstone breccia, weathering buff, very fine grained, 

porous; contains nets of calcite veins that weather 

in relief • • • • • • • • . • • • • . • • • • • • 9.0 

Limestone, dolomitic, dark-gray and brown, dense; in 

beds 0.1 to 0.5 foot thick, and interbedded with buff~ 

weathering sandstone • • • • • • • • • • • • • 12. 5 

Sandstone, weathering buff, very fine grained, massive, 

with silty and calcareous lenses. • • . • • • • • • • 13.0 

Siltstone and siity limestone, light-gray and.dove-gray, 

weathering gray; dense ,to finely granular, medium 

bedded • • .. • • • • • • • • • & • • • • • • • • • • • 8. 0 

9 
Sandstone, gray, weathering buff; very fine, subrounded to rounded grains; brecciated in part, calcareous, massive. Weathering produces irregular 

Thickness 

(feet) 

rounded cavities •••••••••••• ~ • • • • • 18.5 

Limestone, dolomitic, medium- to dark-gray, weathering light-gray; dense, brecciated in places in beds 

0.5 to 3 feet thick, containing lenses of gray to 

black dense .£hert. • • • • • • • • • • • • • • • • • 11.0 

Breccia, light yellow-buff; rna trix silt and very fine 

sand containing sea t'tered rounded medium grains and 

fragments of sandstone and' gray blocks of limestone 

ranging from 0.1 to J.O feet in diameter; massive, 

calcareous, weathering produces irregular rounded 

cavities, arches and windows • • • • • • • • • . • • 27.0 

Sandstone, light-yellow, weathering light-buff; very fine to medium grained, calcareous, porous and weak, 

massive with strong cross-bedding in places. • • • • 40.0 

Sandstone breccia, weathering buff; silty, calcaraous; 

contains fragments of sandstone and limestone averaging about 4 IIU11. in diameter. In sharp contact with 

underlying massive Webei; sandstone and probably disconformable • • • • • • . . • • . 3. 0 

Total thicknass of lower member 

Total thickness of Park City formation. 

CARBONIFEROUS SYST~~ 

Pennsylvanian series 

Weber sandstone 

. . . . . 268~5 

413.5 

Sandstone, gray to white, weathering gray; very fine 

grained, calcareous, massive, cross-bedded in the 

upper part with some dead oil ~n the pores • • • . • 118.0 

Limestone, slightly dolomitic, light-gray, weathering 

yellowish-gray; fine to medium grained, in thin beds 

0.03 to 1.0 foot thick, silty in the upper part with 

abundant dense, gray chert nodules •••••••• • 14.0 

10 
Sandstone, light-gray, weathering gray; very fine 

grained with considerable dolomitic matrix, massive 

Thickness 

(feet) 

beds . • • • . . . • . • . . . . ~ , . _ . • . . . . • 22 • 5 

Limestone, dolomitic, and sandy; light gray-Prawn, 

weathering gray; dense to finely granular, containing 

many very fine sand grains, abundant nodules of yellow, 

brown-weathering chert with a nucleus of dense gray 

chert in same nodules; in thin beds 0.3 to 2.0 feet 

thick . . . . . . . . . . . . . . . . . . . . . . . . 32.0 

Sandstone, light-gray, weathering buff and gray; very 

fine grained, calcareous, silty in beds 1 to 3 feet 

thick; contains many joints; forms a slope • • • • • 35.0 

Sandstone, buff and white, weathering gray and buff; 

very fine grained; grains are mainly clear quartz with 

scattered pink and dark-colored grains; silty, slightly calcareous in massive beds 6 to 10 feet thick, 

thin'breccia zone at the base in places and several 

small fracture zones; forms cliff • • • • • • . • • • 57.0 

Sandstone, medium-gray, weathering buff; very fine 

grained, silty and calcareous; abundant elongate, 

dense gray chert nodules or lenses; the unit is massive with obscure thin to medium beds; upit is weak 

and forms a notch in the sandstone cliff. Contact 

with the overlying sandstone is sharp and wavy . 22.5 

Sandstone, light-buff, weathering gray and _buff; very 

fine grained, silty, slightly calcareous; in massive 

beds 6 to 10 feet thick, with small-scale crossbedding, widely spaced joints; forms cliff . • • • • 11?.0 

Sandstone, mainly light-gray to buff, weathering buff; 

very fine grained with silty beds; is principally 

friable sandstone, in part calcareous with few quartzose beds, massive, with considerable small-scale 

cross-bedding; contains some dolomitic limestone beds, 

and near the base reddish-brown sandstone, siltstone, 

and shale are interbedded with the buff sandstone. A 

detailed ~ection of this unit was not measured . • • llOo.ojt 

Total thickness of Weber' sandstone. • . . 15oo.ot 

11 
Morgan formation 

Upper member 

Measured at "The Slope" in the east 'WB.ll of Duchesne 

River Canyon about one mile north of Stockmore Ranger 

Station. (Locality No. 3 on sketch map) 

Siltstone and very fine· grained, cross-laminated 

Thickness 

(feet) 

sandstone, reddish-brown, wea~hering blocky • • . • 13.0 

Sandstone, white, weathering yellow-buff; very fine 

grained, silty; ranges from laminae to massive beds 

6 to· 10 feet thick, one ?ed of red-brown, calcareous, 

silty muqstone 2.5 feet thick occurs 6 feet below the 

top .. . . . . . . . . . . · . . . . . . . . . . . . . . 30. 5 

• Mudstone, red-brown, calcareous, silty, weathering 

blocky ••••.•••••••.•••••• -. 4.0 

' Siltstone and very fine grained sandstone; red-brown, 

yellow-brown and purple; calcareous with li.niastone 

nodules in places; massive, cliff forming, laminated 

in p1'3.ces with three _prominent beds • • • • • • • • • 25.0 ' , 

Shale, red and gray with interbedded red-brown siltstone and limestone nodules; calcareous, thin beds 

0.1 to 2.0 feet thick, slope forming, about 20 percent c..oncealed • • . • • . • • • • • • • • • . • . • • 17.0 

Siltstone.and very fine grained sandstone, white, 

weathering light yellow-buff and reddish toward the 

top, calcareous with limestone nodules in the upper 

part, laminae to massive beds forming a cliff • . 25.0 

Mudstone, red-brown, calcareous, blocky, about 50 

percent concealed • • • • . • • . . • . . . • • • • • 8.4 

Sandstone, conglomeratic, light-gray, weathering red 

and purple; very fine grained with small pebbles of 

limestone near the middle; contains dense gray and 

red chert stringers • .. • • • . • • • • • • • 4. 5 

Concealed, probably soft red shale . . 

Sandstone, light-gray and brown, weathering red-brown 

and purple; very fine grained, very calcareous, 

10.0 

massive, cross-bedded • • • • • • . • • • • • • • • • ?.0 
90 p~rcent concealed, red and gray shales with lightpurple calcareous siltstone J.6 feet thick 14 feet 

Thickness 

(feet) 

above the base . • • • • • • • . . • • • . . . 41.0 

Limestone, gray, stained reddish-brown; dense, with 

wavy bands of silt . • • • • • • • • • • • • • • J.O 

Sandstone, conglomera tic, gray, weathering red-brown; 

very fine grained, containing angular pebbles of. 

limestone and red siltstone averaging 5 mm. in dia~ 

meter near the top, quartzose and irregularly 

lamina ted • • • • • • • . • . • • • . • . . • • 2 .• 0 

Mudstone and siltst~ne, dark to light purplish-red 

mudstones, weathering blocky, and purplish-red and 

brown mottled calcareous nodular siltstones • • • • , 11.6 

Sandstone, mottled brown and purple, very fine grained 

and quartzos·e . • . • • • • • . . • • . 2.0 

Total thickness of upper momber . . . . 204.0 

Lower member 

Limestone, light-gray, weathering gray, dense, massive, 

containing 15 percent dense vitreous red and white 

chert. Contact with overlying sandstone sharp, uneven, 

with 1 to 2 feet relief in horizontal distance of 4 

feet produced by large masses of chert extending into· 

the overlying sandstone, possibly disconforrr.able • • 6.8 

Eighty percent concealed; probably mainly white 

calcareous shale or marl containing limestone nodules 

near the top. • • • • • • • • . • • . . • • .• • • • 13.0 

Limestone, light-gray, weathering gray; medium crystalline; shaly in upper part, sandy in the basal 1 foot 

with 3 to 10 mm.limestone pebbles; massive; forrns the 

·top of the limestone cliff; contains fossils including: 

Spirifer, Compcsita, and fragments of other fossils • 5.6 

Siltstone and very fine grained sandstone; gray and 

brown in the lower part, reddish-purple in the upper · 2 feet; very calcareous; contains stringers of brown 

and white chert • . • • . • • • . . • • • • • • • • • 5. 2 

1) 
Limestone, light-gray and brown, weathering gray; 

dense to finely crystalline, containing pseudo-oolites 

and fossil fragments in lower 10 feet; upper part 

Thickness 

(feet) 

massive, irregularly bedded with lenses of laminated 

siltstone and dense red and brown chert nodules • • • 17 .o 

Limestone, light-gray, weathering white; dense, partly 

brecciated, massive, weak, generally concealed • • • 8.3 

Limestone, light-brown, weathering gray; dense, ~seudooolitic; nodules and nasses of dense, vitreous, .brown 

and white chert parallel to bedding make up 10 to 20 

percent of the rock. A green, very calcareous siltstone, 0.8 foot thick, occurs 3.5 feet above the 

'ba-se • • • • • • • • . • • • • • • • • • • • • • • • • 7.5 

Limestone, light-gray and brown, weathering gray; 

dense, sandy at the base; in beds 3 to 6 feet thick; 

forms scarp. • . . • • • • • . • •.• • • • . • 18.0 

Sandstone and sandy limestone, gray and white, weathering gray and greenish-gray; very fine grained to silty; 

contains ·scattered white chert nodules near the base; 

beds 1 to 4 feet thick in the lower half of the unit, 

massive above. Chert brecciated ,in p;trt and the top 

of the unit includes limestone fragments averaging 10 

mm. in diameter and scattered large sand grains • • • 23.0 

Limestone, light-gray below, becoming dark-gray above, 

weathering medium-gray; dense to finely crystalline, 

sandy near the ba~e; massive; contains scattered 

fossils; and near the top scattered dense white chert 

nodules. The upper part has a slight petroliferous 

odur . .· . . . . . . . . . . . . . . . . . . . . . . 9.4 

Sandstone, white, weathering brown; very fine grained, 

calcareous, grading laterally into sandy limestone. • 6.5 

Limestone, white to light-gray and brown, weathering 

gray; dense to finely crystalline, argillaceous in the 

upper and lower parts; in thin to thick beds containing a zone of brown and white dense chert nodules and 

rrasses near the top of a 6-foot bed; contains ~rany 

fossils, including Derbya, Linoproductus, nictyoclostus 

and Composita • • • • • • • • • • • • • • • . • • • • 13.3 

14 
Sandstone, calcareous, gray and brown, weathering a 

darker gray and brown; ~ntains fine to very fine 

roUnded quartz grains; gray be~s, massive, knotty, 

containing much cement; brqwn beds 0.5 to 1.5 feet 

Thickness 

(feet) 

thick, ~~ry calcareous, but break across the grains • 10.0 

Limestone, light-gray and brown, weathering gray and 

yellow-gray; dense to finely crystalline, argillaceous 

in the upper part; contains crinoid sterna and other 

fossils. This limestone forms the base of the limestone 9liff • • • • • • • • • • • • • • • • • • • • • 20.0 

Shale, about 20 percent concea~ed, gray with streaks 

of red; very calcareous; contalns interbedded limestone and sandstone and zones of limestone nodules; 

many molds of ostracods occur in a zone near the top. 

Coarsely crystalline l~estone 3.5 feet thick, 16 

feet above the base contains many fossils including 

Derbya, Spirifer, Punctospirifer, and Composita • • • 47.0 

Limestone and shale. Limestone, light-gray to brown, 

weathering gray to yellowish-gray; in beds 1 to 10 

feet thick; dense to ccarsely crystalline; contains 

many fossil fragments in places. Shale, light-grc.y 

to white, with streaks of red; very calcareous, in 

beds 0.5 to 3 feet thick, is a minor part of the 

unit • • • • • • • • • • • • . . . . . Total thickness lower member 

Total thickness of Morgan formation . . . Mississippian series 

Black shale unit 

Concealed, due to slump1ng in Duchesne River canyon. 

In the Blind Stream area· and in Soaostone Basin this 

unit is exposed and includes 200 to.250 feet of soft 

black shale containing beds of fossiliferous lime- stone~ Fossils from these beds were examined QY Helen 

Duncan and James Steele' Williams (personal communication) who consider them to be Brazer (Mississippian) 

in age . .. . . . . .. . . . . . . . . . . . . . . . ~ 

15 

32.0 

242.6 

446.6 
-Humbug formation 

Section measure4 in a- gully on the west side of 

Duchesne River, about 1 mile north of the junction 

of North Fork with West Fork. (Locality No. 4 on 

sketch rrap) . . 

Sandstone~ siltstone, and interbedded limestone. 

Very fine grairred, calcareous, white sandstone, 

weathering yellow and grading upward into greenishgray, shaly sandstone and siltstone. Thin beds of 

Thickness 

(fe~t) 

dense gray limestone in the basal 5 feet • • • . • • 17.0 

Limestone, light to dark gray-brown; dense, breccia ted, fractured, and cut by numerous calcite veins; 

in thin bed~ 0.1 to 2 feet thick. Grades into the 

overlying sandstone • • • • • • • • • • • • • . . , . 

Sandstone, white, weathering yellow; contains chiefly 

30.0 

fine subrounded grains, very calcareous . • • • • • • 2.5 

Limestone, medium-gray, weathering dark-gray; dense 

to finely crystalline, brecciated in the lower part 

and silty in the upper part; contains numerous calcite 

veins; fractures into irregular blocks • ~ • • . • • 6.6 

Sandstone and limestone breccia, weak, friable white 

sandstone, weathering yellow; contains fine subrounded 

quartz grains ,and pink chert, (?).grains; is1 mainly 

thin bedded but contains two' 6-foot beds of sandstone, 

the upper one of which is cross-bedded. Thin beds of 

limestone and limestone· breccias are interbedded with 

the sandstone and are most common in the upper part. 

The sandstone contains mealy white chert locally • • 46.0 

Concealed •• I • • •. • • e • • • • • e 8 • e • e e e 

Limestone breccia, large blocks of rrassiva l.imestone 

breccia slumped somewhat but probably nearly in 

28.t 

place • • • . • . • • • 22.0 

Concealed • • • . • . • • . • • • • • • • • • . . . . Limestone breccia, light gray-brown, weathering lightgray; matrix dense to finely crystalline limestone, 

with blocks of brown and gray limestone averaging about 

16 

30.0 
• 

3 em. in diameter; .contains scattered fine to coarse 

rounded sand grains. The more sandy parts of the unit 

tend to weather yellow and calcite vugs are common • 

Limestone, light-gray to gray-brown, weatherirtg~~­

brown; finely crystalline, sandy and brecciated in 

part, mainly in thin beds 0.2 to 0.4 foot thick, in 

part laminated, but one bed is 6 feet thick. The 

basal bed contains coarse rounded grains of dense 

limestone and quartz, and chert pebbles. Calcite 

vugs are common. The limestone grades laterally into 

very sandy breccia having limestone blocks 3 to 5 em. 

in length. This unit forros a cliff in places but is 

concealed elsewhere. Tha contact with the underlying 

Deaeret limestone apparently is disconformable • • • 

Total thickness of Humbug formation •• . . . . . . . 

Deseret limestone 

Section measured in the west wall of Duchesne River 

and in a canyon tributary to North Fork about 3 miles 

north of the junction with West Fork. (Locality No. 5 

on sketch nap} 

Limestone, about 50 percent concealed, light to medium· 

brown, weathering·gray-brown; finely crystalline, 

silty and dolomitic in some beds; beds, 0.3 to 3 feet 

thick, calcite vugs and a few gray and white banded 

chert nodules are present in the lower part and darkThickness 

(feet) 

100.0 

7?.0 

359.0 

gray chert nodules are present in the upper part • •' 90.0 

Limestone; lower half light to medium brown, weathering gray-brown; finely crystalline, with stringers and 

nodules of white, weathering gray, banded chert; upper 

half dark-sray, weathering gray, with yellow-brown , chert nodules; mainly medium bedded, but beds ~P to 8 

feet thick are present; scattered fossils ~re present 

throughout, including nany ~rtly silicified cup and 

colonial corals • • • • . • • • • . . • • • . . • • • • , 100.0 

Limestone, dark-gray and brown, weathering gray; dense 

to finely. crystalline; contains a few fossils and in 

the upper 10 feat white and yellow-brown mealy chert 

intergrown with limestone • • . • • • o • • • • • • • 60.0 

Limestone, light-gray to brown, weathering gray-brown; 

crinoidal in places; finely crystalline, sugary and 

1? 
porous; contains numerous large calcite vugs, and gray 

and white dense or mealy chert; mainly thin bedded, 

0.3 to 1.0 foot thick, with an 11-foot bed at the 

top . • • • . • 

Limestone, thin bedded, cherty; light- to dark-gray 

and brown, weathering gray; finely to coarsely crystalline, depending on the fossil content; some beds emit 

a petroliferous odor; chert abundant, making up 30 

percent of the rock in the lower 20 to 30 feet and 

about 10 percent in the upper part, occurring in beds 

and irregular nodules cutting across the beds, mainly 

dense gray chert weath~ring gray, but some mealy chert 

is present in the upper 20 feet. Fossils cammpn, in-

'Thickness 

{feet) 

40.0 

cluding Soirifer, Linoproductus, and others • • • 64~0 

Limestone, cherty, dark-gray; finely crystalline·; in 

thin beds less than 1 foot thick. Chert makes up 

about 15 percent of the.rock and is mainly earthy, 

but black dense chert is present • • • . • • • • 18.0 

Chert and limestone; about ?5 percent of the rock is 

mealy white and gray chert intergrown with limestone 

and weathering white or light yellow-brown; limestone, 

dark-gray, silty, weathering brownish-gray, in thin 

beds ranging from 0.1 to 0.3 foot in thickness •• p 22.0 

Limestone, light-gray to white, weathering gray; 

massive, coarsely crystalline; contains many fossils, 

including Spirifer • . • . • . • • • . • • • • • • • ~12.0 

Limestone, dolamitic~ light-brown, weathering'mediumb,rown; massive, finely crystalline, porous; contains 

a few fossil molds • • • • • • . • • • • • • 27.0 

Limestone, light-gray; oolitic and fossiliferous 6.5 

Limestone,.dark-gray, weathering gray and brown; finely 

crystalline, contains coarsely crystalline lenses with 

fossils; in medium~thfck beds 1 to .3 feet thick • • • 30.0 

Limestone, dolomitic, light to Jlledium brown, weathering gray to brown; finely crystQ.lline, sugo.ry, porous; 

contains calcite vugs; weathered surfa9es show laminations due to variation~ in color and grain size; lower 

6o feet is about 50 percent concealed and the beds are 

1 to 4 feet thick; upper part is massive and forms a 

cliff. Colonial corals are common at several 

horizons • • • . • • • ~ • • • • • • • • • • • • • • 110.0 

18 
Limestone, light-gray or brown to dark-gray, weather- . ing light-gray; finely to coarsely crystalline; in 

beds ranging from 1 to 3 feet thick; contains. scattered nodules of mealy chert weathering white to buff 

and many colonial and cup corals that are partly 

Thickness 

(feet) 

silicified . • • • • • • • • • • • • • • • • . • • • 26.0 

Limestone, light- to dark-gray and brown; dense to 

cbarsely crystalline varying with the fossil content; 

in beds averaging about 1 foot thick, but the unit 

appears massive in many outcrops, forming a prominent 

ledge and •~tcrfall in the canyon in which this section was measured. Cup corals are numerous in the 

upper part of the unit • • . . • . . . . • • • • • • 27. 0 

Total thickness of Deseret limestone • . . . . . . . 

Madison limestone 

Limestone, dark-gray and brown, weathering light-gray; 

dense to finely crystalline; contains lenses of coarsely crystalline limestone with an abundance of fossils; 

has scattered dense black chert nodules in the upper 

631.5 

20 feet; beds are thin, averaging about 0.3 foot in 

thickness, separated by yellow-weathering shaly partings and shale beds in the lower pg.rt; some of the 

beds have a petroliferous odor • • • • • • • • • • • 210.0 

Limestone, dark-gray to brown, weathering light-gray; · coarsely crystalline; cross-bedded; grading to dense 

above; contain~ fossil fragments at the base; massive; 

forms a prominent ledge • • • • . • • • • • • • • • 26.0 

Limestone, dolomitic, light-gray, weathering the same 

color; finely crystallinti, massive; weathers back by 

vertical spalling and forms a notch beneath the overlying cliff-forming ltmestone • • • • • • • • • . • • 8.0 

Limestone, dolomitic, light-gray, weatheri~g graybrown; finely crystalline, very sandy, mainly coarse; 

angular to rounded grains of quartz occur in laminae 

and scattered through the limestone. Grades into the 

overlying limestone • • • . • • .. • • 2. 5 

Total thickness of Madison limestone . . .... 246.5 

19 
CAMBRIAN (?) SYSTEM 

Pine Valley quartzite 

Sandstone, gray, greenish-gray and brown, weathering 

brown and red-brown; massive and cross-bedded in the 

lower part, thin bedded and silty in the upper part. 

Base concealed • • • • . • • . • .. . • . • . • • 

0 

20 

Thickness 

(feet) 

3?5~0t 
References cited 

Berkey, C~ P., Stratigraphy of the Uinta l&ountains: Geol. 

Soc. America Bull., vol. 16, 1905. 

Emmons, S. F., Uinta Mountains: Geol. Soc. America Bull. 

vel. 18, 190?. 

Forrester, J. D., Structure of the Uinta Mountains: Geol. 

Soc. America Eull., vel. 48, 193?. 

Gilluly, James, Geology and ore deposits of the Stockton 

and Fairfield quadrangles, Utah: U. S. Geol. Survey Prof. 

Paper 173, 1932. 

Thompson, 1,;. L., Pennsylvanian rocks and fusulinids of 

east Utah and northwest Colorado correlated with Kansas section: 

Kansas Geol. Survey Bull. 60, pt. 2, 1945. 

Weeks, F. B., Stratigraphy and structure of the Uinta Range~ Geol. Soc. America Bull,, vel. 18, 1907. 

Williams, J. Stewart, 11 Pa:rk City" beds on the southwest 

flanks of the Uinta Mountains, Utah: JUn. Assoc. Petroleum 

Geologists Bull., vol. 23, 1939. 

Carboniferous forrrations of the Uinta and northern wasatch 

Mountains, Utah: Geol. Soc. america Bull., vol. 54, 1943.