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Geological Society of America Bulletin

doi: 10.1130/0016-7606(1971)82[581:NACOSU]2.0.CO;2 1971;82;581-602Geological Society of America Bulletin

WOODWARDMAX D CRITTENDEN, JR., FREDERICK E SCHAEFFER, D. E TRIMBLE and LEE A IdahoBasal Cambrian Sequences in Western Utah and Southeastern Nomenclature and Correlation of Some Upper Precambrian and

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MAX D. CRITTENDEN, JR.

FREDERICK E. SCHAEFFERD. E. TRIMBLELEE A. WOODWARD

U.S. Geological Survey, 345 Middlefield Road, Menlo Park,California 94025Southern Colorado State College, Pueblo, Colorado 81001U.S. Geological Survey, Denver, Colorado 80225University of New Mexico, Albuquerque, New Mexico 87106

Nomenclature and Correlation of Some UpperPrecambrian and Basal Cambrian Sequencesin Western Utah and Southeastern Idaho

ABSTRACT

Recent stratigraphic studies in three widelyseparated localities in southeastern Idaho andwestern Utah have revealed a startling con-tinuity of both individual rock units and ofrock sequences over a distance of some 300mi parallel to the strike of a late Precambrianand Cambrian depositional trough. Between15,000 and 25,000 ft of beds were depositedin the axis of the trough, whereas only 1000to 3300 ft of correlative rocks were laid downon the shelf to the east. In several areas adiamictite is present near the base of the se-quence; this is underlain locally and overlaingenerally by argillites containing lenticularlimestones and dolomites; these in turn aresucceeded by quartzitic rocks containing athick grayish-red to maroon unit—the Mu-tual Formation. In each area the sequenceincludes, at the top, quartzites typical of thebasal Cambrian. Deposition in the basin wasessentially continuous from late Precambrianinto Cambrian time but was interrupted byuplift and erosion on the shelf. The hingeline of the ancient seaway is inferred to havecoincided roughly with the present "Wasatchline," but erosion prior to deposition of theTintic Quartzite has removed most of thedata needed to establish this with certainty.

Rocks in each of the three areas describedhere in detail are regarded as allochthonousand appear to have been thrust eastward dur-ing the Sevier orogeny. A precise reconstruc-tion of the sedimentary basin must thereforeawait not only additional stratigraphic stud-ies in such areas as the Promontory Range ofUtah and the Bannock and Malad Ranges ofsouthern Idaho, but also final resolution ofthe structural events.

INTRODUCTION

Geologic mapping and stratigraphic stud-ies in three widely separated areas of thenortheastern part of the Great Basin haveshown that both individual stratigraphic unitsand gross rock sequences of late Precambrianand Cambrian age exhibit remarkable con-tinuity over the 300-mi distance from south-eastern Idaho to central Utah (Fig. l). Thesequences are 15,000 to 25,000 ft thick wheremost complete and appear to record contin-uous sedimentation from late Precambrianinto Cambrian time. All three areas are withinthe deformed part of the Sevier erogenic beltand are presumed to have been transportedeastward several tens of miles from theiroriginal sites of deposition. However, be-cause correlative rocks in shelf sections to theeast are thin or absent and the rates of thick-ening and of original facies change are un-known, the precise amount of telescoping bytectonic transport remains uncertain.

The purpose of this paper is to name, de-scribe, and correlate the thickest and leastcomplicated sections of these rocks, in thehope that the units and sequences defined inthese areas can be recognized in other areaswhere exposures are limited or where struc-tural complexity makes it impossible to workout a complete stratigraphic section.

Authors are listed alphabetically; responsi-bility is shared jointly for sections on correla-tion, age, paleogeography, and structure, butis carried individually for stratigraphic de-scription of specific areas.

The rocks of the Pocatello, Idaho, areanow assigned to the Precambrian were firstdescribed by Anderson (1928) and includedin the Cambrian; Ludlum (1942) was the first

Geological Society of America Bulletin, v. 82, p. 581-602, 8 figs., March 1971

581



582 CRITTENDEN AND OTHERS-PRECAMBRIAN AND CAMBRIAN SEQUENCES

Figure 1. Index map showing location andtectonic setting of stratigraphic sectionsdescribed.

to recognize that some of them are Precam-brian. Similar rocks in the area near Hunts-ville, Utah, were first recognized by Black-welder (1910) and were mapped in recon-naissance and described briefly by Eardley(1944). The earliest and most significant syn-thesis of younger Precambrian rocks in north-ern Utah was that of Eardley and Hatch(1940); more recent summaries include thoseof Cohenour (1959) and Condie (1966,1969).Precambrian rocks in the Beaver Mountainswere originally assigned to the Ordovicianand Silurian(P) by Butler (in Butler andothers, 1910, p. 511) because he failed torecognize the thrust fault which separatedthem from the immediately underlying lowerPaleozoic rocks. The presence of a thick Pre-cambrian section in this area was noted byD.M. Lemmon, W. C. Jeffs, and others, dur-ing mapping following World War II, andthe rocks are assigned to the Precambrian onthe geologic map of southwestern Utah(Hintze, 1963).

Stratigraphic studies of the older rocks inthe Pocatello area were started in 1961 byF. E. Schaeffer during preparation of a geo-logic map of Bannock County, Idaho, for

the Idaho Bureau of Mines and Geology.Schaeffer was the first to distinguish the majorsubdivisions within the Precambrian rocks ofthis area and to recognize that they could betraced over the adjoining parts of south-eastern Idaho. These subdivisions were usedin mapping the Pocatello and Michaud 15-minute quadrangles by D. E. Trimble from1962 to 1965 (Trimble and Schaeffer, 1965)and in more recent mapping of the Michaudand Pocatello 15-minute quadrangles.

Geologic mapping at a scale of 1:24,000in the Huntsville area by Crittenden largelybetween 1964 and 1966 led to definition ofthe Huntsville sequence (Crittenden, 1967)in a little-deformed area in the Browns Holequadrangle. Mapping designed to establishthe stratigraphy of the lower diamictite-bearing units is continuing in structurallycomplex areas near Willard Peak, northwestof Huntsville.

Stratigraphic relations in the shelf areawere established during mapping in the Cot-tonwood district east of Salt Lake City by theU.S. Geological Survey between 1940 andI960 (Calkins and Butler, 1943; Crittenden,1965a, 1965b).

Stratigraphic studies in the Beaver Moun-tains were completed by Woodward during1966 (Woodward, 1968).

POCATELLO AREA, IDAHO

The rocks of the Pocatello area, southeast-ern Idaho, appear to be typical of the con-formable depositional sequence of upper Pre-cambrian and lowermost Cambrian rocks ofthe eastern part of the Great Basin. Inasmuchas they constitute the thickest known sectionof those rocks and because the units definedhere can be recognized over a wide area, theymay well serve as a standard for much ofsoutheastern Idaho. More than 25,000 ft ofdominantly quartzitic rocks, of which morethan 20,000 ft probably are Precambrian,underlie Middle Cambrian limestones. LowerCambrian fossils have not been discovered inthis area but were found in correlative rocksin the Portneuf Range (Oriel, 1965). Therocks below the Cambrian carbonates form-erly assigned to the Brigham Formation(Anderson, 1928; Ludlum, 1942, 1943) aredivided into six formational units, four ofwhich are Precambrian. New names are intro-duced here for three of these and for the twoCambrian units.



POCATELLO FORMATION 583

POCATELLO FORMATIONThe lowest and oldest rocks in the Poca-

tello area comprise clastic, volcanic, and car-bonate rocks of probable marine origin thatwere designated the Pocatello Formation byLudlum (1942). That term is retained here,and the formation is divided into four mem-bers, a lower member, mainly argillite; adiamictite1 member, a volcanic member; andan upper member, also dominantly argillite.The type section of.the Pocatello Formationis a composite of those of the individualmembers, defined below.

The lower member of the Pocatello Forma-tion consists of black, thinly laminated, slatyargillite, phyllitic siltite, and brown quartzite.A thickness of about 700 ft is observed, butthe total thickness is uncertain because thebase is not exposed. The type section of thelower member is designated as the sectionfrom the canyon bottom to near the top ofthe west slope of a small canyon just northof the Portneuf River, in the SVi sec. 15, andNi/2 sec. 22, T. 7 S., R. 35 E., about 7 misoutheast of Pocatello (A-B, Fig. 2).

These slaty rocks are overlain conformablyby several thousand feet of diamictite-bearingrocks, here named the Scout Mountain Mem-ber, with excellent exposures on the summitof and on the ridge approximately 2 mi northand south of Scout Mountain in Tps. 8 and9 S., R. 35 E., about 15 mi south-southeast ofPocatello (Fig. 2). Owing to severe faulting,a complete section is not present either at thetype locality on Scout Mountain, or else-where. The reference section for this unit istherefore designated as a composite of threepartial sections as follows: (l) from the crest,down the west slope of the ridge immediatelynortheast of Portneuf in the SW!4 sec. 15, T.7 S., R. 35 E. (C-C, Fig. 2); (2) from thebase, up the west slope to the crest of thecorresponding ridge immediately south ofthe river, in the W!/2 sec. 27, T. 7 S., R. 35 E.,(C'-C",Fig. 2); (3) up part of the west slopeof the same ridge about a mile south in theNW/4 sec. 34, T. 7 S., R. 35 E. (C"-D,Fig. 2). Sections C-C and C'-C" could notbe matched, and an unknown, but probablysmall, amount of section is believed to bemissing. The following is a generalized de-

1 Diamictite: A nonsorted sedimentary rock con-sisting of sand and/or larger particles in a muddymatrix (modified from Flint and others, I960).

scription of these composite sections. TheScout Mountain Member has at the base 65ft of limestone, locally recrystallized to densemarble. This is succeeded by 100 ft of medium-grained gray quartzite with much interbeddedsiltstone at the top. This, in turn, is overlainby the main body of the member, consistingof intercalated diamictite and quartzite. It isseveral thousand feet thick including theintercalated volcanics (see below). Abovethis thick unit, but still within the ScoutMountain Member are as much as 1200 ft ofquartzite and minor argillite, 150 to 350 ft ofcobble conglomerate, an additional 100 to300 ft of quartzite, an upper bed of diamictite,on the order of 100 ft thick, a distinctive 2-ftbed of laminated dolomite, 100 to 800 ft ofquartzite with small amounts of argillite, anda 15-ft bed of limestone, designated the topof the member.

The typical diamictite is a massive darkpurplish- to greenish-black rock consistingof pebble- to boulder-size clasts in a volu-minous fine-grained matrix characterized byangular sand-size grains. The clasts arerounded to angular, up to 3 ft in diameter,and of diverse lithologies, including quartz-ite, granite, dolomite or limestone, maficigneous rocks, and argillite. This rock is be-lieved to be partly of glacial origin becauseof its massive character, the anomalous angu-larity of the sand-size grains, the abnormallylarge ratio of fine matrix to clasts, and thepresence of large clasts that are faceted orstriated. It is also suspected to be of sub-marine origin because it is interstratified withseveral thousand feet of quartzite, and withseveral thin beds of limestone and dolomitepresumed to have been of marine origin.

Metavolcanic rocks, herein designated theBannock Volcanic Member, form a wedge atleast 1000 ft thick that interfingers with thediamictites of the Scout Mountain Member.This volcanic unit was first designated theBannock Volcanic Formation by Anderson(1928, p. 3), who defined it as including allthe exposed rocks below his Black RockLimestone and inferred that it might be Cam-brian. It was later restricted by Ludlum (1942,1943) to exclude most of the sedimentaryrocks and was assigned to the Precambrian.Both volcanic flows and breccias are present;the massive rocks show a wide range ofporphyritic textures, and include both vesicu-lar and amygdaloidal types. Fragmental tex-tures ranging from coarse volcanic breccia to




tuff can also be recognized readily, although of the Bannock Volcanic Member are lo-all are fairly typical "greenstones" showing cated on the west slopes of Chinks Peak in

sees. 32 and 33, T. 6 S., R. 35 E., about 4mi east-southeast of Pocatello (E-F, Fig. 2).

The upper member of the Pocatello Form-

weak schistosity, and consisting largely ofalbite, chlorite, epidote, and calcite.

Exposures here designated the type section112'30'

Pocatello Formation

p€pu upper memberpCps Scout Mtn MemberpCpb Bannock Volcanic Membe

2°45'

Figure 2. Map of area near Pocatello, Idaho, showing location of type sections fordescribed Precambrian and Cambrian units.

newly



POCATELLO FORMATION 585

tion consists of nearly 2000 ft of black, thinlylaminated phyllitic to slaty argillite that con-tains much interbedded quartzite in the upperhalf. As thus defined, it corresponds essen-tially to Ludlum's (1942) "varved slate se-ries." The type section is designated as ex-tending across the top of a narrow saddleabout a mile southeast of Scout Mountain insec. 2, T. 9 S., R. 35 E. (G-H, Fig. 2).

Blackrock Canyon Limestone

The thickest carbonate unit of the Pre-cambrian section in the Pocatello area con-sists of several hundred feet of fine-grainedgray limestone interbedded with quartziteand minor variegated argillite. This lime-stone unit was originally named the BlackRock Limestone by Anderson (1928, p. 4);it was later designated the Blackrock Lime-stone by Ludlum (1942, p. 92-93), but ishere renamed the Blackrock Canyon Lime-stone because the name "Blackrock" is pre-empted. The type section is on the east sideof lower Blackrock Canyon in sec. 14, T. 7S., R. 35 E., about 7.5 mi southeast of Poca-tello (I-J, Fig. 2).

Brigham Quartzite of Andersonand Ludlum

The 15,000-ft interval of detrital rocks,consisting mainly of quartzite, between theunderlying Blackrock Canyon Limestone andthe lowest carbonate rocks of Cambrian age,was assigned to the Brigham Quartzite byboth Anderson (1928) and Ludlum (1942).However, the term is not used at Pocatello inthis report because this interval is thick andcontains several distinctive lithologic units,and because the term has been used in sev-eral different ways in adjoining parts of Utahand Idaho (see Huntsville area, Utah, thispaper). In recent mapping of the Pocatelloquadrangle (Trimble, unpub. data), this in-terval is divided into six new formations; thelower four are believed to be Precambrian, theupper two are presumed to include Cambrianrocks.

Papoose Creek Formation. Overlyingthe Blackrock Canyon Limestone in the Poca-tello area are about 1800 ft of distinctively,irregularly bedded, mottled gray and brownsiltite and very fine-grained quartzite, heredesignated the Papoose Creek Formation.The name is taken from exposures in PapooseCreek, the type locality south of the PortneufRiver about 5 mi southeast of Pocatello,

Idaho (Fig. 2). The type section (K-L, Fig. 2)is in sec. 35, T. 7 S., R. 35 E., and sees. 2 and3, T. 8 S., R. 35 E., in the headwaters andjust east of the canyon of Papoose Creekwhere the formation is a little more than 600ft thick. The Papoose Creek Formation ispoorly exposed in most places and must berecognized by float. The beds of siltite orquartzite, commonly 1 to 3 rnm thick, formalternating layers of light gray and light todark brown that are undulating, broken, andslightly offset in many places. This deforma-tion of the bedding is probably penecon-temporaneous and characterizes the forma-tion. The lower contact is drawn at the topof the highest carbonate of the underlyingBlackrock Canyon Limestone. Locally, thePapoose Creek appears to overlie conform-ably the Blackrock Canyon Limestone, butgreat variations in thickness suggest that thecontact may be a disconformity. The forma-tion is presumed to be marine.

Caddy Canyon Quartzite. The PapooseCreek Formation is overlain by several thou-sand feet of vitreous quartzite here named theCaddy Canyon Quartzite. The type section isin Caddy Canyon, north of the PortneufRiver in sec. 13, T. 7 S., R. 35 E., and sec.18, T. 7 S., R. 36 E., about 8 mi southeast ofPocatello (M-N, Fig. 2). The base of theformation is exposed on the west side of aspur west of the mouth of Caddy Canyon insec. 24, T. 7 S., R. 35 E.; the upper contactis exposed on the ridge east of the canyon insec. 7, T. 7 S., R. 36 E. The formation iswidely exposed as smooth slopes and ledges.The lower part of the Caddy Canyon Quartz-ite is mostly white- to tan-weathering, light-colored vitreous orthoquartzite that containssome interbedded greenish argillite or siltite.In places, especially in the lowermost part,there are many interbeds, some rather thick,of irregularly bedded, fine-grained quartziteand siltite much like that of the conformablyunderlying Papoose Creek Formation. Thelower contact is placed at the base of thelowermost light-colored quartzite in the tran-sitional sequence between the predominantlysilty Papoose Creek Formation and the light-colored orthoquartzite of the Caddy CanyonQuartzite. Somewhat above the middle of theCaddy Canyon, and overlying the light-colored quartzite, there is at many placesabout 50 ft of dolomite or, less commonly,limestone. Above the dolomite or limestone,the quartzite and argillite beds that constitute




the upper part of the formation commonlyare pinkish, purplish, or maroon. In theuppermost few hundred feet of the CaddyCanyon are several interbeds of greenishargillke and siltite.

Inkom Formation. The Caddy CanyonQuartzite is overlain by 800 to 1000 ft(locally as much as 2300 ft) of very fine-grained detrital rocks here named the InkomFormation. In the Pocatello area these rocksare characteristically greenish, although lo-cally as much as 200 ft of grayish-red ordusty-red argillite is present at the top. Thename is taken from the small town of Inkom,Idaho, and the type section is in a smallcanyon north of the Portneuf River about amile west. The lower part of the Inkom ismainly greenish phyllite. This grades upwardinto greenish-gray to light olive-gray argil-lite or slate, siltite, and very fine-grainedquartzite. The unit also contains a few bedsof conglomerate or impure micaceous quartz-ite. The lower contact of the Inkom is placedat the top of the highest quartzite of theCaddy Canyon Quartzite, although somebeds of argillite like the Inkom are presentbelow it. The top is placed at the base ofmassive quartzite ledges of the overlyingMutual Formation and is generally quitesharp.

Mutual Formation. The Inkom Forma-tion is overlain by a massive 3000 ft quartziteunit whose characteristic grayish-red color(5R 4/2)2 contrasts strongly with that of theunderlying greenish argillite. This unit iscorrelated with the type Mutual Formationsoutheast of Salt Lake City, Utah (Crittendenand others, 1952) on the basis of its charac-teristic lithology, color, and position. In thePocatello area, the quartzites of the Mutualare coarse-grained, pebbly or conglomeratic,and persistently cross-bedded. The colorranges from light grayish-red (5R 5 2 ) todark grayish-red (5R 3/2) or purplish-black(5RP 2/1). In addition to quartzite, the unitcontains relatively thin but distinctive bedsof argillite, one of which is more than 200 ftthick. Most of the argillite is dusky-red tovery dark red; locally, it may be olive drab

-' Numerical designations derived from the RockColor Chart (Goddard and others, 1948) are givenfor the Mutual Formation, because color is a dis-tinctive and characterizing feature of this unit.Adjective designations are used throughout theremainder of the report.

(5Y 5/2) or greenish-gray (5GY 6/1). Thebasal contact is placed at a conspicuous andabrupt change from argillite to quartzite; inmost places greenish-red quartzite overliesthe Inkom Formation. The Mutual Forma-tion is present in all of the basin sequencesand is the youngest unit that one can be sureis entirely of Precambrian age.

Camelback Mountain Quartzite. TheMutual Formation of the Pocatello area isoverlain by as much as 3500 ft of light-colored vitreous orthoquartzite that is litho-logically similar to the Cambrian TinticQuartzite of the Tintic district of Utah andthe Prospect Mountain Quartzite (restricted)of the northern part of the Great Basin. Thisorthoquartzite is here designated the Camel-back Mountain Quartzite for exposures onCamelback Mountain east of Pocatello,Idaho (Fig. 2).This section is severely faulted,however, and a section on the east slope ofWild Horse Mountain in sees. 22 and 23, T.7 S., R. 34 E., about 4.5 mi south-southwestof Pocatello (O-R, Fig. 2) is designated analternate type section. This formation gener-ally forms smooth slopes. It is composed ofthick-bedded to massive, locally cross-bedded,medium-grained vitreous orthoquartzite thatweathers white, tan, brown, and brownish-gray. It is mostly white at the base. TheCamelback Mountain Quartzite lacks the red-dish hues found in older units and containslittle argillite or phyllite. The basal contact isconformable and transitional with the under-lying Mutual Formation. Locally, the base ismarked by a pebble conglomerate, 5 to 15 ftthick, that contains light colored pebbles asmuch as 1.5 in. in diameter in a pinkishquartzitic matrix. No fossils have been foundin the Camelback Mountain Quartzite, butCambrian fossils occur about 300 ft above thebase of the overlying unit. The CamelbackMountain is therefore assigned a Precambrianand Early Cambrian age. It is considered tobe of marine origin.

Gibson Jack Formation. The uppermostclastic unit at Pocatello is composed of morethan 1000 ft of argillaceous siltstone andshaly argillite with interbeds of quartzite andsandstone that is here named the GibsonJack Formation. The name is taken from ex-posures on Gibson Jack Creek south of thePortneuf River about 5 mi south of Pocatello.The type locality is at the head of GibsonJack Creek in sec. 33, T. 7 S., R. 34 E., about8 mi south-southwest of Pocatello (S-T,



HUNTSVILLE AREA, UTAH 587

Fig. 2). The formation consists of argillaceoussiltstone and papery-weathering argillite withminor interbeds of sandstone or quartzite.The lower part is mostly tan, olive, or gray-green; the upper part is mainly pale yellowish-brown. A 100-ft bed of light gray medium-grained quartzite is present about 350 ftabove the base and other beds are presentnear the top. Two or more beds of thin-bedded argillaceous limestone, tens of feetthick, also occur near the top, but they sel-dom crop out. The basal contact of the Gib-son Jack Formation is placed at the base ofthe first thick siltstone or argillite; althoughthis leaves some argillaceous beds in theunderlying Camelback Mountain Quartzite,they are commonly thin.

The upper contact is placed at the base ofthe first thick limestone or dolomite litho-logically equivalent to the Langston or UteFormations of Walcott (I908b). The onlyfossil found to date in the Gibson Jack For-mation is the Cambrian arthropod Narnia,which was found about 300 ft above thebase. The only other occurrence of this rareform is in Middle Cambrian rocks in BritishColumbia (A. R. Palmer, 1968, written com-mun.), but its actual range is unknown.Therefore, because the Early Cambrian Olenel-lus was reported by Oriel (1965) in bedsbelieved to be equivalent to or slightly higherthan the Gibson Jack, this formation is as-signed an Early Cambrian age.

HUNTSVILLE AREA, UTAH

General Features

About 13,000 ft of younger Precambrianand basal Cambrian rocks are exposed eastand northeast of Huntsville, Utah. This sec-tion, which has been divided into sevenformational units, should serve as a standardfor northwestern Utah as the Pocatello sec-tion does for southeastern Idaho.

The existence of a thick section of youngerPrecambrian rocks near Huntsville was rec-ognized by Blackwelder as early as 1910.Indeed, its presence there and its absencenear Ogden, where the basal Cambrian quartz-ite (Tintic) rests directly on crystalline base-ment, was the basis for his identification ofthe Willard thrust. The general character ofthese rocks and their structural relations werefurther elaborated by Eardley and Hatch(1940), and Eardley (1944). Although youngerPrecambrian rocks are present both east and

west of Huntsville, the present descriptionwill be restricted to the rocks that crop outto the northeast and east (Fig. 3). As a conse-quence, the lowest units of the more com-plete section at Pocatello—argillite and thediamictites of the Scout Mountain Memberof the Pocatello Formation—are absent fromthis section. Previous work (Eardley andHatch, 1940) has shown that diamictites(Fig. 4) are present above the Willard thrustbetween Willard Peak and Brigham City, andrecent mapping by Crittenden indicates thatthey occur 2000 to 3000 ft below the lowestrocks exposed east of Huntsville, but theirexact stratigraphic relations are still beingstudied.

The sequence of Precambrian and basalCambrian rocks east of Huntsville will bedescribed briefly, beginning with the oldestand continuing to the base of the carbonateunits which here are of Middle Cambrianage. The lowest units are well exposed in thefoothills and along the lower reaches of boththe South Fork and Middle Fork of theOgden River east and northeast of Hunts-ville.

Maple Canyon Formation

The name Maple Canyon Formation ishere given to about 1000 to 1500 ft of clasticrocks which are divided into three informalmembers on the basis of lithology. The nameis taken from Maple Canyon about 6 mi eastof Huntsville, Utah, and the type locality isnear the mouth of the canyon, beginning inthe north half of sec. 9, T. 6 N., R. 2 E.(A-B, Fig. 3).

The lowest unit, designated the argillitemember, consists of about 500 ft of olivedrab to locally gray, thin-bedded, silty argil-lite or siltstone which contains one or morebeds of greenish-gray arkosic sandstone. Thisunit is exposed at several places along thefoothills northwest from Maple Canyon, andin each place it is the lowest unit of Precam-brian rocks exposed on this side of the valley.Although the rocks in the Huntsville area asa whole are little metamorphosed, this unit istypically phyllitic and commonly shows small-scale crenulations and folds usually at anangle to the bedding (Fig. 5); locally theserocks show well-defined schistosity.

The middle member of the Maple CanyonFormation is informally designated the greenarkose member. It consists of 500 to 1000 ftof relatively thick-bedded, massive, very fine-



111°47'30" 111°37'30" EXPLANATION41°22'30" . .

Quaternary andTertiary rocks

_____ ____ "1

UndifferentiatedlS<shale and I Seelimestone m

Geertsen Canyonf <Jz»Quartzite J a:S;

~\ CO

Browns HoleFormation

OLCD

aet0-

Mutual Fm

lnkom(?)Formation

Caddy Canyon (?)Quartzite

Kelley CanyonFormation

Maple CanyonFormation

Section referred to in text

Figure 3. Map of area near Huntsville, Utah, showing location of type sections for newly described Precambrian andCambrian units.




Figure 4. Diamictite consisting of sub-rounded to subangular clasts of quartzite, gra-nitic rocks, and carbonates in a black fine-grained matrix. Exposures are in Willard thrustsheet north of Willard Peak, Utah.

grained arkosic sandstone. On fresh fractures,this rock is a very pale greenish-gray, but thiscolor is commonly obscured by weatheringand, at a distance, the unit forms roundedledges that are dark gray or brown. Indi-vidual beds range from 1 to 2.5 ft in thick-ness and are separated by thin partings ofsiltstone or thin-bedded argillite. The moremassive beds are distinguished from quartz-ites in other parts of the section by theirremarkably perfect sorting, and by the abun-dance of K-feldspar, which makes up asmuch as 40 percent of some stained slabs. Asa result of the feldspar content, this unittends to be less quartzitic in character thanother parts of the section. The feldspar con-tent is variable, however, with some areascontaining lenticular bodies of well-cementedvitreous and pebbly quartzite as much as200 ft thick.

Figure 5. Argillite member of Maple CanyonFormation near Huntsville, Utah. Crenulatedbedding is nearly vertical, parallel to pen;schistosity dips 30° to left.

The uppermost member of the MapleCanyon Formation is designated the con-glomerate member. It consists of two con-glomerates or, locally, quartzites and an in-tervening argillite. The member as a wholeranges from 60 to 500 ft in thickness but inthe type area immediately north of MapleCanyon, averages about 200 ft. Much betterexposures are present on the top of a roundedhill just north of the mouth of the middlefork of Ogden River (C-D, Fig. 3) and thisis designated a reference section for thismember. The lowermost conglomerate con-sists of 50 to 200 ft of white to light gray,conglomeratic quartzite. Clasts range frompebble to small cobble in size and consistmainly of white quartz, or white, gray to palepink quartzite. Pale green quartzite contain-ing chromian mica (x-ray fluorescence) is asparse but significant constituent. These dis-tinctive clasts closely resemble the greenquartzites near Park Valley in the Raft RiverRange of Utah (Felix, 1956). Similar clastsare present also in the tillites of AntelopeIsland and in the Dutch Peak Tillite ofCohenour (1959) in the Sheeprock Moun-tains of Utah.

The two conglomerates are separated by10 to 100 ft of olive drab laminated argillite.This unit is not well exposed and commonlymust be mapped by its silver-gray-weatheringflakes in the soil. The upper part of the con-glomerate member commonly consists of awhite, coarse-grained rock that ranges fromquartzite to conglomerate. In places it is only50 ft thick and consists entirely of pebble tosmall cobble conglomerate; in other placesit is as much as 200 ft thick and consistsalmost entirely of quartzite with only a fewpebbles at the base. In a few places the ma-trix, instead of being light colored vitreousquartzite, grades into a dark gray, tan-weathering, friable, impure sandstone or gray-wacke whose anomalous appearance isvaguely reminiscent of a diamictite. Thisleads to the suspicion that this clastic mem-ber may be correlative with the uppermostthin unit of diamictite in the Scout MountainMember of the Pocatello Formation, whichoccupies a corresponding position immedi-ately below laminated dolomites at Pocatello(Fig. 6).

Kelley Canyon Formation

The conglomerate member of the MapleCanyon Formation is overlain by a domi-



590 CRITTENDEN AND OTHERS—PRECAMBRIAN AND CAMBRIAN SEQUENCES

Figure 6. Tan-weathering laminated dolo-mite at base of Kelley Canyon Formation, nearHuntsville, Utah.

nantly argillaceous unit to which the newname Kelley Canyon Formation is here given.The type section is located in the head ofKelley Canyon (E-F, Fig. 3) in the southhalf of sec. 3, T. 6 N., R. 2 E., about 3.5 mieast of Huntsville. Although argillaceousrocks predominate, the unit contains muchinterbedded quartzite in the upper portionand grades into the overlying quartzite. Theformation is distinctive in that it contains theonly limestones and dolomites known withinthe Precambrian rocks in this area.

The Kelley Canyon Formation begins atthe base with a persistent 10-ft bed of thinlylaminated, tan-weathering, fine-grained dolo-mite. The laminae are commonly about 1 mmthick but tend to be cyclic, giving the ap-pearance of bedding 1 to 2 cm thick. Locally,individual laminae consist of chert, givingthe rock a distinctive ribbed appearance (Fig.6). Although the unit is poorly exposed ingeneral, its presence can usually be verifiedby large and persistent dolomite blocks inthe float. The dolomite is overlain by lavender-gray, purplish-gray or olive drab shale andsiltstone locally containing thin beds ofgreenish fine-grained sandstone. Like the ar-gillite at the base of the Maple CanyonFormation, these units are commonly phyl-litic.

The middle part of the formation consistsof gray to lavender-gray argillite enclosingseveral lenticular bodies of thin-beddedpinkish-gray silty limestone. The gray color,absence of laminae, and intercalations withshale distinguish these carbonate units fromthe dolomite at the base of the unit. Althoughthey are not persistent enough to map every-

where, these limestones occur at the samehorizon as the Blackrock Canyon Limestoneof the Pocatello area, and it is possible thatthey represent the distal end of a tongue ofthis formation.

Above the thin-bedded limestones, theargillites of the Kelley Canyon Formationare largely olive drab- or tan-weathering andcontain increasing amounts of thin- tomedium-bedded quartzite. The top of theformation is poorly defined and cannot al-ways be identified with certainty. In manyplaces, however, it is marked by a zone ofvery thin-bedded white quartzite (.25 to .75in. in thickness) with intervening wavy lami-nae of red-weathering shale and silt.

Brigham Group

History and definition—The term BrighamFormation was first applied by Walcott(I908a, 1908b), to a 2000-ft thickness ofmassive quartzites and sandstones in theWasatch Range immediately east of BrighamCity, Utah. Unfortunately, he did not give aprecise locality or measured section, nor showthe unit on a map. More importantly, forproblems of the Precambrian, the base wascompletely undefined. As a consequence,two strongly contrasting usages of the termBrigham have evolved. Most authors work-ing in southern Idaho (for example, Mans-field, 1920, 1927, 1929; Anderson, 1928;Ludlum, 1942, 1943; and Bright, I960), haveused the term Brigham in an inclusive sensefor the entire sequence of dominantly quartz-itic rocks below the Cambrian carbonates.Another group, working mainly in northernUtah (for example, Eardley and Hatch, 1940;Lochman-Balk, 1955; Williams, 1958; andStokes, 1963), used the term in a restrictedsense for only the uppermost 2000 to 5000 ftof light colored quartzites that were pre-sumed to be Cambrian.

As a result of these persistent conflicts, theterm "Brigham" is here raised to group rank,and this term is recommended for use wher-ever the units here defined or others of for-mational rank can be recognized. In areaswhere exposures are inadequate or structuralcomplications are too severe to permit sub-division, the term Brigham Quartzite can beused in an inclusive sense for rocks withinthe same stratigraphic limits defined belowfor the Brigham Group. Thus far, these for-mational units have been recognized by




Trimble near Pocatello, by Schaeffer in muchof Bannock County, Idaho, and by Crittendennear Huntsville, Utah. Reconnaissance sug-gests that at least some of the lithologiescharacteristic of these units can be distin-guished in intervening areas also, as nearPreston, Idaho (Bright, I960). Detailed studyof such areas will be required to determinewhich of the formational units describedhere are present.

In the Huntsville area, the Brigham Groupis here defined as comprising approximately7000 ft of beds, largely quartzite, in theinterval between the top of the Kelley Can-yon Formation and the base of the lowestcarbonatic or pelitic rocks of Cambrian age.It thus includes the Caddy Canyon( ?) Quartz-ite, Inkom(?), Mutual, and Browns HoleFormations and Geertsen Canyon Quartzite.Two of these units (Caddy Canyon and In-kom) are named elsewhere in this report forrocks in the Pocatello area; the Mutual For-mation was described in the Cottonwoodarea near Salt Lake City (Crittenden andothers, 1952); the remaining two units aredenned below for the first time.

The best exposed and least faulted sectionof the Brigham Group in northeastern Utahis on the north wall of the Middle Fork ofOgden River, beginning at the base of theCaddy Canyon(?) Quartzite near the south-east corner of sec. 21, T. 7 N., R. 2 E., andextending northwest to the base of Cambrianlimestones exposed near the head of GeertsenCanyon in section 18. This stratigraphic sec-tion is here designated the principal referencesection for the Brigham Group. Redefinitionof the Brigham in terms of this referencesection is necessary because reconnaissancemapping at Walcott's presumed type localityalong U.S. Highway 89~91, 2 mi east ofBrigham City, has shown that the lower 5000ft of the Brigham Group, as here defined, iscut out by a north-striking fault which placesbeds near the base of the Geertsen CanyonQuartzite in fault contact with beds near thetop of the Kelley Canyon Formation. Thenewly designated reference section is about18 mi southeast along the regional strikefrom the type locality, but the units have al-ready been mapped at 1:24,000 scale oversome 12 mi of the intervening distance. Al-though many normal faults are present in thearea between the two sections, there appear tobe no significant thrust faults.

Caddy Canyon (?) Quartzite

The lowest formation of the BrighamGroup in the Huntsville area is a brown- totan-weathering, impure quartzite tentativelycorrelated with the Caddy Canyon Quartziteof the Pocatello area. The lower contact isgradational, the slope-forming argillites ofthe underlying Kelley Canyon Formationgiving way upward through an interval of afew tens of feet, or locally as much as 100 to200 ft, to cliff-forming quartzite ledges. Nearthe base, argillite and thin-bedded fine-grained quartzite make up nearly half of theformation; near the top, however, argillace-ous rocks are limited to partings a few inchesto a few feet thick. Similarly, quartzite ledgesnear the base are impure and weather toshades of brown, whereas those near the topare increasingly pure, form steep cliffs, andweather light gray or tan. The upper contactis very sharp, and generally is marked by atopographic bench exposing gently wavybedding surfaces, from which the overlyingless resistant shale has been stripped. TheCaddy Canyon(?) Quartzite thickens sys-tematically from about 1500 ft in the SouthFork of Ogden River to 2500 ft in the areanorth of Huntsville.

Inkom(?) Formation

Above the massive cliff-forming quartzitesis a bench- or slope-forming argillite unit 360to 450 ft thick. The upper half is domi-nantly grayish-red; the lower half is olivedrab to light green. This unit is tentativelycorrelated with the Inkom Formation of thePocatello area on the basis of stratigraphicposition and general character. Although theInkom at its type area is thicker and isdominantly green, the lithology is essentiallyidentical, and the larger proportion of grayish-red rocks here is thought to represent a de-crease in the reducing capacity of the en-vironment, suggesting that perhaps theHuntsville section was deposited in shal-lower water.

Mutual Formation

One of the most distinctive units in thePrecambrian rocks of northern Utah is thestrikingly colored grayish-red quartzite whichcan be recognized widely from the BeaverMountains, Utah, on the south, to Pocatello,Idaho, on the north. This unit was desig-




nated the Mutual Formation by Crittendenand others (1952) in the Cottonwood areanear Salt Lake City. It consists dominantlyof grayish-red to pale purplish or pale pinkcoarse-grained, locally pebbly or feldspathicquartzite with abundant cross-bedding. Inthis area, as in the type locality, it containslocal lenticular interbeds of argillite, most ofwhich are the same distinctive grayish-red orpale purplish-red as the surrounding quartz-ite. Mapping northwest of Huntsville hasshown that this unit is intercalated locallywith both basalt and rhyolitic tuff.

Browns Hole FormationThe unit here designated by the new name

Browns Hole Formation consists of twohthologically distinctive members, a lowermember characterized by volcanics and anupper member of terra cotta quartzite. Thetype section is along the middle fork ofOgden River on slopes northwest of BrownsHole, near the center of sec. 14, T. 7 N., R.2 E., Browns Hole quadrangle (G-H, Fig. 3).Still better exposures are present high on thenorth slopes of the middle fork extendingalong strike about 2 mi southwestward fromthe northeast corner of section 10 into Geert-sen Canyon. This formation has no litho-logic counterpart at Pocatello or in theBeaver Mountains.

The volcanic member is a slope-formingunit 182 to 460 ft thick. Although character-ized by volcanics, it also includes fine-grainedsediments ranging from shale to thin-beddedquartzite. The volcanics observed in greatestabundance are basalt, either gray, massive,and fine-grained, or vesicular and amygda-loidal. In places, black to red scoriaceousrocks of boulder size weather out from thefiner matrix. Locally, volcanic fragments showa wide range in composition, and includeporphyritic types with stony or vitrophyric-appearing groundmass. Both the massive andfragmental rocks are reworked along strike asrounded cobbles and boulders which dimin-ish in abundance southward and finally giveway in the South Fork of the Ogden Riverto a zone of brown thin-bedded quartzite andargillite containing only traces of volcanicmaterial.

The upper member of the Browns HoleFormation throughout the Huntsville area isa distinctive terra cotta colored, medium- tofine-grained quartzite 100 to 150 ft thick. It

is distinguished by its uniformity of grainsize, the presence of well rounded, locallyfrosted grains, and widespread small- tolarge-scale cross-bedding. Locally, the weath-ered unit is friable and strongly resembles theJurassic Nugget Sandstone of the WasatchMountains near Salt Lake City. The presenceof frosted grains suggests an eolian environ-ment, but bedding features indicate thatfinal deposition may have taken place inshallow water.

The range of Rb Sr ratios in the basalt istoo small to permit adequate whole-rockdating, even though the rocks are remarkablyfresh in many places. It is hoped that a com-bination of this basalt and the rhyolitic tuffdiscovered recently in the underlying MutualFormation may provide the necessary rangein composition. The age of this unit , likethat of all of those below, is presumed to bePrecambrian.

Geertsen Canyon Quartzite

The basalt and quartzite of the BrownsHole Formation are overlain with apparentconformity by a very thick, light coloredconglomeratic quartzite unit that is heregiven the new name Geertsen Canyon Quartz-ite. Rocks with this lithology underlie fos-siliferous Cambrian shale or carbonatesthroughout the intermountain region of west-ern Utah and much of eastern Nevada. Ineach area, however, a different name hasbeen applied: in Nevada and western Utahthey are generally called the Prospect Moun-tain Quartzite; in central Utah they are com-monly referred to as the Tintic Quartzite; inmuch of northern Utah and southern Idaho,including the Huntsville area, these rockshave been referred ro as the Brigham Quartz-ite. However, because of the conflicting andmore inclusive use of the term "Brigham" inmuch of northeastern Utah and southeasternIdaho, the formation is here given a newname.

The type section of the Geertsen CanyonQuartzite is on the ridge west of GeertsenCanyon, 5 mi north of Huntsville in sections18 and 19, of T. 7 N., R. 2 E. (I-J, Fig. 3). Inthis atea the formation rests with apparentconformity on the terra cotta quartzite mem-ber of the Browns Hole Formation and isoverlain with apparent conformity by brown-weathering dolomite of the Langston Dolo-mite. The total thickness in this area is up-



BEAVER MOUNTAINS, UTAH 593

proximately 4200 ft, divided into a lowermember about 1200 ft thick that is domi-nantly arkosic, and an upper member about3000 ft thick that is dominantly quartzitic.The two are separated by a persistent zone ofconglomerate lenses.

The lower member of the Geertsen CanyonQuartzite has at the base 300 to 400 ft ofvery coarse-grained arkose containing frag-ments of salmon-colored microcline and palegreenish-weathered plagioclase up to a halfinch in size; both the grain size and feldsparcontent diminish upward, however, and theremaining 800 ft or so of this member iswhite- or tan-weathering quartzite.

The contact between the lower and uppermembers of the Geertsen Canyon is drawnat a persistent zone of cobble conglomerates.Where best developed, the conglomerate oc-curs as a single bed 8 to 10 ft thick of 2- to4-in. clasts mainly of reddish-coated veinquartz or quartzite, occasionally of grayquartzite or red jasper. In many areas, how-ever, conglomerate beds a few feet thick arefound throughout a stratigraphic interval 100to 200 ft thick. The upper member of theGeertsen Canyon Quartzite is typical ofbasal Cambrian quartzites throughout theintermountain area. It consists predominantlyof pale buff to white or pale-pink quartzitelocally streaked pale red or pale purple. Ingeneral, it is coarse grained with scatteredpebbles up to an inch in diameter, particu-larly along bedding planes, throughout theunit. Locally, at the top of this member is aninterval about 375 ft thick in which thequartzites are marked by persistent Scolithusand in which the interbedded argillites showabundant fucoidal structures, occasional tri-lobite tracks, and sparse unidentifiable phos-phatic fragments. It seems probable, althoughnot yet demonstrable, that this part of theunit is equivalent to rocks in the PortneufRange called the "quartzite of SedgewickPeak" by Oriel (1965), which have yieldedan olenellid trilobite, and hence are of EarlyCambrian age.

In terms of general position and lithology,the Geertsen Canyon Quartzite is presumedto correlate approximately with the Camel-back Mountain Quartzite of Pocatello andwith the Prospect Mountain Quartzite (re-stricted) of the Beaver Mountains. It isassigned a Precambrian and Early(?) Cam-brian age.

BEAVER MOUNTAINS, UTAHAbout 9000 ft of younger Precambrian and

lowermost Cambrian strata are present in theBeaver Mountains (Fig. l). The uppermostformation is the Prospect Mountain Quartz-ite (restricted, of Woodward, 1968) whichgenerally has been considered to be LowerCambrian; however, the P recambr ian -Cambrian boundary within the Beaver Moun-tains cannot be located precisely (Woodward,1968).

Beneath the Prospect Mountain Quartzite(restricted) are seven units, tentatively con-sidered Precambrian; these have been in-formally numbered 1 through 7, beginningwith the oldest. This concordant section iscorrelated with the younger Precambrian andCambrian sections near Pocatello and Hunts-ville on the basis of remarkable lithologicsimilarities in both individual units and inthe over-all sequence (Fig. 7). The followingbrief descriptions begin at the base; morecomplete descriptions are given by Wood-ward (1967).

Unit 1 consists of medium- to coarse-grained, thick-bedded, light gray, cross-bedded quartzite. Although the base of theunit is not exposed, 970 ft were measured.This unit appears to be correlative with theupper part of the upper member of the Poca-tello Formation.

Overlying this quartzite unit is about 1300ft of interbedded quartzite, slate, argillite andmarble of unit 2. The lower 500 ft consists ofthin-bedded gray quartzite with intercalatedred and green slate laminae and thin-beddedquartzose marble. A thin zone of intraforma-tional edge-wise quartzite conglomerate oc-curs near the top of this sequence. Overlyingit is a 25-ft cliff formed by very thick-beddedquartzose calcite marble. Above the cliff-making marble, the unit consists of thinlyinterbedded tan, olive-green, and greenish-gray slate, argillite, and quartzite with minorquartzose marble that decreases in abundanceupward. The marble beds, mostly occurringin the lower part of the unit, probably repre-sent, tongues of the Blackrock Canyon Lime-stone of the Pocatello area. The upper part ofunit 2 may be correlative with the PapooseCreek Formation.

Unit 3 consists of 260 ft of quartzite withminor green slate neat the top. The lowerpart of the unit is thick-bedded, medium- to




coarse-grained, whitish and light gray quartz-ite. About 50 ft below the top of the unitthere is an abrupt upward change from lightgray quartzite to dark brown quartzite con-taining subrounded white quartz pebbles upto 2 cm in diameter. The top of the unit isformed by a 15-ft green slate interval and10 ft of overlying very thick-bedded, medium-to coarse-grained, dark gray quartzite. Thisunit appears to be lithologically correlativewith the much thicker Caddy Canyon Quartz-ite of the Pocatello region.

Unit 4 consists of 530 ft of olive-greenslate and argillite with minor thinly inter-calated fine- to medium-grained green quartz-ite. The quartzite is impure, containing abun-dant chlorite and sencite matrix. This greenishunit is the lithologic equivalent of the InkomFormation of the Pocatello area.

Units 5, 6, and 7 of the Beaver Mountainsappear to be lithologically correlative withthe rocks assigned to the Mutual Formationin the Pocatello and Huntsville areas. Unit 5contains 760 ft of thick-bedded, reddish-brown, medium-grained to conglomeraticquartzite. Well-rounded white quartz pebblesup to 3 cm in diameter occur sparsely in thelower beds and become more abundant nearthe top of the unit, forming thin conglom-eratic layers. Unit 6 consists of approximately150 ft of interbedded maroon slate, argillite,and thick-bedded, coarse-grained to grittyquartzite. A composite section of unit 7measures 1175 ft and is composed of purpleconglomeratic quarczite with minor purpleand silver slate and argillite laminae. Thequartzite is medium- to very coarse-grainedand contains abundant but thin gritty andconglomeratic zones with pebbles of whiteand clear quartz or, rarely, jasper up to 1 cmin diameter. Beds are thin near the base ofthis unit but become thicker upward.

The purple quartzite of unit 7 is overlainwith a concordant but sharp contact by pink-ish and tan quartzite characteristic of theProspect Mountain Quartzite (restricted).This unit consists of thick to very thick-bedded, coarse-grained to conglomeraticquartzite; the lowest beds are poorly sortedand gritty, becoming conglomeratic about20 ft above the base of the formation. Thisconglomeratic zone is 20 ft thick and con-tains pink and tan subrounded quartz peb-bles up to 2 cm in diameter. In the succeed-ing 200 ft, pebble-size clasts are scattered,only locally becoming abundant enough to

form thin conglomerate layers. Still higher,pebbles are scarce and the rock is more uni-formly coarse grained or gritty. Pink feldsparclasts, principally microcline, are commonin the lower part of the formation and consti-tute up to 10 percent of some specimens. Thethickness of the Prospect Mountain Quartz-ite (restricted) cannot be measured preciselybecause of faults in the section, but it ap-pears to be at least 4000 ft thick.

OTHER AREAS IN UTAHDugway Range

A 12,000-ft sequence of younger Precam-brian and basal Cambrian rocks in the Dug-way Range, Utah, described by Staatz andCarr (1964), contains rocks equivalent to alarge part of the sections previously describedat Pocatello, Huntsville, and the BeaverMountains. Although Staatz and Carr as-signed these rocks to the Prospect MountainQuartzite, which they designated Lower Cam-brian, they pointed out (1964, p. 16) that thelower part was probably of Precambrian age.The close lithologic similarity between therocks in the Dugway Range and those ofPocatello were pointed out to Trimble byW. J. Carr and later confirmed in the field.

The oldest units exposed in the section atDugway (Fig. 8) are dominantly light col-ored to pinkish-tan, rusty weathering quartz-ite interbedded with considerable olive-drabor tan micaceous shale (units 1 through 6 ofStaatz and Carr, 1964). Except for the pres-ence of a 150-ft pebbly conglomerate (uni t6), this section bears a considerable resem-blance to parts of the Caddy Canyon Quartziteof the Pocatello and Huntsville areas andperhaps part of the underlying Kelley CanyonFormation of Huntsville. The succeedingunit at Dugway (unit 7 of Staatz and Carr)consists of 600 ft of olive-tan, thinly lami-nated shale and siltstone which is virtuallyindistinguishable from the greenish InkomFormation at Pocatello. This unit in turn isoverlain by 1600 ft of coarse-grained "violet"to grayish-red conglomeratic quartzite thatresembles in both character and position theMutual Formation of all three of the areaspreviously described. The Mutual equiva-lents at Dugway are overlain by approxi-mately 4500 ft of white or tan quartzite (unit8 of Staatz and Carr, 1964) that appears to becorrelative with the Camelback MountainQuartzite of the Pocatello area, the Geertsen



Pocitello, Idaho(This report)

Huntsville, Utah(Thii raport)

Sheeprock Mountains(Cohanour, 1959)

Canyon Range(Christiansen, 19S2)

Beaver Mountains(This report end Woodward, 1968)

ifeA t̂feaay^J:

TinticQuertzite

" Purple sh.l.

13 Purple Quirtzite

, !Cs j

Limestone ordolomite

STiSa Sbale or schist

Volcanic rocks

Gneiss andampM oolite

Prospect MountainQuartzite(restricted)

i !

Figure 7. North-south correlation of younger Precambrian and basal Cambrian rocks from Pocatello, Idaho, to Beaver Mountains, Utah.

CRITTENDEN AND OTHERS, FIGURE 7Geological Society of America Bulletin, v. 82, no. 3



ern Deep Creek Range

(Bick. 1966)

V -^ '

•

-t- J--V — =^ — '

"-̂ ~— ̂ -~— ~j

? ~ " h tE?sSte^̂^^^^^•—^ ~-~ — "^sS^S =

ty/fwv*ty&^

Pink to grayquart zite

Purple shaleand sandstone

Shale

Schist

Quartzite

Schist

(i

^Diamictite 1

1 *~Schist

Dugway Range

>taatz and Carr, 1964

y ^ KV- K

- = • ' * - v- Jr

» ».<..».»,w»;fc

"C '^ Y ^

h — N

~~~"*'

-5,000 FEET

Sheeprock Mountains

(Cohenour, 1959)

Cottonwood area

(Crittenden and others, 1952)

Q^*(U* -̂ '.......ai f m

/

Tintic Quartzile

Big Cottonwood Formatio

Little Willow Formation

Figure 8. East-west correlation of younger Precamhrian and basal Cambrian rocks in western Utah.




Canyon Quartzite of Huntsville, and theProspect Mountain Quartzite (restricted) inthe Seaver Mountains.

Sheeprock Mountains

A 15,000-ft section of younger Precam-brian and basal Cambrian rocks described byCohenour (1959) in the Sheeprock Moun-tains of central Utah also contains lithologicequivalents of the rocks recognized at Poca-tello and Huntsville (Fig. 7). The lower partof the section, designated the SheeprockGroup by Harris (1958, p. 6) and the Sheep-rock Series by Cohenour (1959, p- 17), con-tains a lower "black-banded phyllite" 2690ft thick that together with about 1470 ft ofdark slate, conglomerate, and graywacke,

Erobably is correlative with the lower mem-er of the Pocatello Formation. This is over-

lain by a diamictite unit, called the DutchPeak Tillite by Cohenour (1959, p. 19),which correlates in both character and strati-graphic relations with the diamictite-bearingScout Mountain Member of the PocatelloFormation. More recent mapping in thesouthern Sheeprock Mountains by H. T.Morris and R. W. Kopf (1968, oral commun.)indicates that diamictites in that area inter-tongue with normal marine sedimentary rocksas they do at Pocatello. Above the DutchPeak Tillite is the upper part of the Sheep-rock Series, which consists of olive-green ortan shale and a white quartzite. These sug-gest the lithology of the upper member ofthe Pocatello Formation and the PapooseCreek Formation at Pocatello and of theKelley Canyon Formation at Huntsville, al-though the limestone tongues are apparentlyabsent. The Mutual Formation in the Sheep-rock Mountains is thin (900 ft) comparedwith other trough sections, but this may belocal, inasmuch as Groff (1959, p. 25) reportsa 3000-ft section on the slopes of SabieMountain immediately to the east. A smallangular discordance reported by Cohenourat the base of the Mutual shows that theeffects of epeirogenic movements that stronglymodified the section in the shelf areas to theeast (Fig. 8) also were effective locally withinthe basin. A 2500-ft section of white, palegray, or tan quartzite, called Tintic Quartziteby Cohenour (1959), appears to be correla-tive with the Camelback Mountain Quartziteof Pocatello and the Geertsen Canyon Quartz-ite of Huntsville. As in other parts of the

trough (Fig. 7), there is no evidence of astratigraphic break between the Mutual andTintic, and sedimentation appears to havebeen nearly continuous from Precambrian toCambrian time.

Canyon Range

A 9900-ft section of younger Precambrianrocks described by Christiansen (1952) in theCanyon Range (Fig. l) also exhibits thesame sequence and many of the same unitsrecognized to the north and south (Fig. 7).At the base, Christiansen's units 1 through 3occupy the stratigraphic position of theupper member of the Pocatello Formation inIdaho; units 4 and 5 may represent a distaltongue of the Blackrock Canyon Limestoneof Pocatello and equivalents at Huntsvilleinasmuch as they resemble it in both char-acter and position. Units 9, 10 through 12,and 13 are correlated, respectively, with theCaddy Canyon Quartzite, Inkom Formation,and Mutual Formation, recognized in thePocatello, Huntsville, and Beaver sections.Christiansen's unit 15 and the conformablyoverlying quartzite, which he referred to asthe Tintic Quartzite, are the equivalents ofthe Camelback Mountain Quartzite andGeertsen Canyon Quartzite of southern Idahoand Huntsville, and the Prospect MountainQuartzite of the Beaver Mountains and prob-ably contain the same continuous record ofdeposition from Precambrian to Cambriantime.

Antelope Island

The thin but highly significant sequenceof younger Precambrian rocks on AntelopeIsland (Fig. 1) near the eastern edge of GreatSalt Lake was described by Eardley and Hatchin 1940. The crystalline basement is overlainby a few tens of feet of diamictite, a thinshale, and a laminated limestone that closelyresembles the laminated dolomite immedi-ately above the diamictite in the Pocatellosection. This is overlain unconformably by athick cobble and pebble conglomerate thatis typical in every respect of the basal Cam-brian throughout all of northern Utah. Thisunit has been examined repeatedly by one ofthe authors (Crittenden) and also by R. J.Roberts, H. T. Morris and E. W. Tooker,who agree that Eardley and Hatch's originalidentification as Tintic Quartzite was correct,and that Larsen's (1957) correlation with the



REGIONAL CORRELATION AND AGE 597

Mutual Formation (shown also on the Geo-logic Map of northwestern Utah; see Stokes,1963), is in error.

CORRELATION WITHINSEDIMENTARY BASIN

The remarkable similarity of both indi-vidual stratigraphic units and of rock se-quences in a north-south direction is evidentfrom the preceding descriptions. Correlationin this direction (Fig. 7), therefore, presentsfew problems. The key horizons are: (l) thedistinctive and persistent purple to grayish-red quartzite of the Mutual Formation, whichcharacteristically overlies greenish peliticrocks of the Inkom Formation; (2) the im-pure silty carbonates of the Blackrock Can-yon Limestone, thin equivalents of whichreappear at Huntsville, in the Beaver Moun-tains, and the Canyon Range; (3) a few feetof tan-weathering laminated dolomite thatoccurs with remarkable persistence just abovea thin conglomerate at both Pocatello andHuntsville; and (4) the lithologically distinctand genetically significant diamictites.

The unique character and the probableglacial origin of the diamictites in Utah wasrecognized near the turn of the century byBlackwelder (1910) and Hintze (1913). Theseare black boulder-bearing beds containingseveral unusual lithologies. The most dis-tinctive is a massive rock (Fig. 4) consistingof clasts ranging from boulder to small peb-ble size in a muddy matrix. It is remarkablefor its persistent black color (resulting froman abundance of both carbon and pyrite),faceted and striated cobble-size clasts, anom-alously angular character of sand-size frag-ments, and absence of bedding throughmany tens of feet. A second characteristicrock is boulder phyllite in which boulder- tocobble-size clasts are spaced at intervals of afew feet to a few hundred feet (one or twoper outcrop) in thin-bedded black (carbona-ceous) mudstones which have been shearedto phyllite. A third characteristic lithology ismedium-bedded, coarse-grained, greenish-gray arkosic quartzite or graywacke. Theserocks occur through about 5000 ft of sectionat Pocatello, are present along strike belowthe sequence at Huntsville, and intertonguethrough 4000 ft of beds in the Sheeprockarea (Cohenour, 1959). These relations sug-

f est deposition in a subsiding marine troughy glacial tongues, which in some areas

dumped till directly, in others yielded ice-rafted clasts, and in many other areas yieldedonly the reworked or redistributed productsof a complex depositional process like thatdescribed by Frakes and Crowell (1969, p.1027-1029) for Paleozoic glaciation in SouthAmerica.

East-west correlation (Fig. 8) across theassumed trend of the depositional basin canbe established with confidence only as farwest as the Dugway Range. Farther west,correlation with sections in easternmost Ne-vada and along the Utah-Nevada line (north-ern Deep Creek Range, Schell Creek Range,Pilot Range; Fig. 1) have been suggested byWoodward (1968), but variation within indi-vidual sections, together with a lack of keybeds, makes these correlations much moretenuous than those within the basin.

Correlation eastward from the basin sec-tions of Pocatello and Huntsville to theCottonwood area, which appears to representa shelf environment, can be established withconsiderable confidence (Fig. 8). The basalCambrian quartzites are identical lithologi-cally but thin from some 4000 ft in the axisof the trough to less than 1000 ft on theshelf. Moreover, the Tintic Quartzite in boththe Cottonwood areas and in the autochthonnear Ogden appears to represent only theupper member of the Geertsen CanyonQuartzite at Huntsville; the lower member iscut out along the low-angle unconformity.Locally, in the Cottonwood area, the entireMutual Formation also has been cut out bythis unconformity, and the Tintic Quartziterests directly on the diamictite-bearing rocks,there designated the Mineral Fork Tillite(Crittenden and others, 1952).

A second angular unconformity is locallypresent in the shelf section at the base of theMutual Formation. As a result, coarse boul-der conglomerate at the base of the Mutualrests directly on the Mineral Fork Tillite—the equivalent of the lower part of the thickbasin sequence at Pocatello. The thicknessof beds cut out by this unconformity amountsto nearly 10,000 ft.

REGIONAL CORRELATIONAND AGE

All of the rocks here described lie withinthe Big Cottonwood subprovince of youngerPrecambrian rocks as defined by Condie(1969). However, without detailed mapping




and stratigraphic studies of the kind here re-ported, correlation both within that sub-province and with adjoining provinces wasconsidered tenuous (Condie, 1969, p. 83and 86).

Recognizing the unique lithologic char-acter of the diamictites, whether or not theyare of glacial origin, it is now possible tosubdivide the major younger Precambriansequences of western North America, eventhough strict temporal equivalence cannotbe demonstrated. Thick prediamictite se-quences which may be in part temporalequivalents, include the Purcell Series ofBritish Columbia, the Belt Supergroup ofMontana and Idaho, and the Big Cotton-wood Formation of Utah. Diamictites arerecognized in all or parts of the Toby Con-glomerate of British Columbia (Walker,1926), the Scout Mountain Member of thePocatello Formation, the Mineral Fork Til-lite, and the Dutch Peak Tillite of Cohenour(1959) in Utah (Fig. 3), and the KingstonPeak Formation in southern California (Hew-ett, 1956, p. 27). Thick post-diamictite se-quences inc lude the remainder of theWindermere Group of British Columbia, theBrigham Group and its equivalents here de-scribed near Pocatello, Idaho, near Hunts-ville, and in the Beaver Mountain sections inUtah. Temporal equivalence of the diamictitesis strengthened by their close association withvolcanic rocks in the Pocatello section (Ban-nock Volcanic Member), in Washington(Leola Volcanics), and in British Columbia(Irene Volcanics), a relation pointed out byYates (1968) and others.

The age span of each of the rock sequencesdescribed above has not been determined inthe eastern Great Basin. The entire sequenceis obviously bracketed between the under-lying crystalline rocks, which are dated as2.3 b.y. in the eastern Uinta Mountains(Hansen, 1963, and 1965, p. 31) and 1.6 b.y.in the Farmington area between Salt LakeCity and Ogden (Giletti and Gast, 1961) andthe basal Cambrian with which the upper-most units are gradational in the basin sec-tions. If the correlations suggested above arevalid, the dates established for Belt rocks inMontana, Idaho, and British Columbia (Ob-radovich and Peterman, 1968) imply that theBig Cottonwood Formation is between 1 to1.5 b.y. old. The bulk of the rocks in thePocatello and Huntsville sections should bethe same age as the Windermere, that is, be-

tween 570 and 700 m.y. (see Leech, in Lowden,1961, p. 6), inasmuch as all three groups ofrocks have a diamictite at the base and appearto have been deposited continuously, or atleast without detectable tectonic disturbance,into Cambrian time.

PALEOGEOGRAPHY ANDTECTONIC RELATIONS

The sequence of rocks at Pocatello, to-gether with that present, although not yetcompletely mapped, at Huntsville, suggeststhe following generalized sequence of eventsin the eastern Great Basin, in very late Pre-cambrian time.

1. Accumulation of a thick series of blackargillaceous sediments containing thintongues of dolomite or limestone whichthicken westward. The shoreline during thistime probably lay close to the present site ofthe Wasatch line; the axis of the trough wasat least 40 mi farther west, possibly close tothe Nevada line. The presence of black (car-bonaceous) pyritic mudstones or shales inthe lower member of the Pocatello Formationand at Huntsville suggests relatively deepquiet water and euxinic bottom conditions.

2. This depositional basin was invadedperiodically from an unknown eastern sourceby tongues and sheets of ice which depositeddiamictites, at times directly from ice, attimes by ice-rafting of boulders beyond theglacial limits. Reworking and redepositionby slumping and turbidity currents is alsoprobable (Condie, 1966, 1969). An episodeof volcanism intervened in the Pocatello areaduring this same interval.

3. Normal marine sedimentation then re-sumed, including the deposition of tonguesof carbonate intercalated with silt-size elasticswhose green or purple color and scarcity ofcarbon or pyrite suggests normal rather thaneuxinic bottom conditions.

4. Gradually, the supply of sand-size de-bris increased, leading to accumulation ofthe quartzitic sequences that characterize theBrigham Group. Deposition appears to havebeen continuous into the Cambrian in partsof the basin, but the presence of volcanicsand eolian sands in the Browns Hole Forma-tion of the Huntsville sequence suggests thatterrestrial conditions existed, at least tempo-rarily, perhaps representing a slowing in therate of basin subsidence.

5. The abundant cross-bedding and "peb-bled" bedding surfaces that characterize the



REFERENCES CITED 599

upper parts of the Geertsen Canyon Quartz-ite indicate that shallow water conditionspersisted into Cambrian time throughout thearea.

Although a complete reconstruction oflate Precambrian to Early Cambrian paleo-geography is impossible, the preceding frame-work is sufficient to help clarify certaintectonic relations, particularly in northernUtah. That the thick Precambrian sequencesof Huntsville and the northern Wasatch areallochthonous and are derived from the west,was evidently suspected by Blackwelder(Eardley, 1944, p. 849), and was one of twostructural alternatives considered by Eardleyand Hatch in 1940 (p. 867-872). More re-cently, Eardley (1968, 1969) has proposedthat the Huntsville sequence is autochthon-ous, having been deposited in a trough onthe east side of a late Precambrian uplift,which is marked by the very thin AntelopeIsland sequence.

The following evidence, drawn from thepreceding discussion, is believed by the writ-ers to support the concept of eastward thrust-ing, (l) The startling similarity of the Hunts-ville, Pocatello, Sheeprock, and BeaverMountain sections implies that they all ac-cumulated in the axis of a subsiding troughin which deposition was nearly continuousfrom Precambrian into Cambrian time: (2)The Antelope Island section, like that in theCottonwood area near Salt Lake City, indi-cates intermittent uplift, with the result thatonly equivalents of the lowermost (diamic-tite) and uppermost (Tintic Quartzite) partsof the Pocatello and Huntsville sequence ispresent in these areas. The vastly thicker andmore complete Huntsville section must havebeen deposited well to the west of AntelopeIsland. Thick sections of younger Precam-brian rocks exposed on Promontory Point,Fremont Island, and Little Mountain are be-lieved by Crittenden to be part of the Hunts-ville sequence, and presumably came fromstill farther west. (3) Accumulation of theHuntsville sequence at its present location inan embayment east of Antelope Island andeast of the extensive exposures of the Farm-ington Canyon Complex in the Ogden areais unlikely because the late Precambrian up-lift proposed by Eardley, and recorded by theprofound unconformity exposed in thoseareas, would have yielded abundant con-glomerates and coarse gneissic clasts whichare conspicuously absent in the Huntsville

sequence, and which, had they been present,would have caused this sequence to contraststrongly with the rocks at Pocatello. Simi-larly, uplift and stripping of the entire Hunts-ville sequence from the Antelope Island -Farmington area during Early Cambrianshould have been recorded by an abundanceof Hunts ville-type clasts in the Geertsen Can-yon Quartzite. These also are conspicuouslylacking.

The'logical alternative is that thick youngerPrecambrian sequences were never depositedat Antelope Island, and that the Huntsvillesequence has been thrust eastward over theAntelope Island section. This conclusion isstrongly reinforced by evidence from otherparts of the stratigraphic column (Rigo,1968; Crittenden, 1961; Armstrong, 1968).Although the 40-mi transport of the frontaledges of the thrust plates proposed in 1961still appears reasonable, stratigraphic andstructutal relations in ateas such as the RaftRiver Range (Felix, 1956; Compton, 1969)suggest that much greater distances are pos-sible. A more complete reconstruction of thepaleogeography of late Ptecambrian rocksmust await solution of these and relatedsttuctural problems.

ACKNOWLEDGMENTS

It is a pleasure to acknowledge the benefitof discussions of Precambrian stratigraphyand nomenclature with R. A. Bayley, R. R.Compton, W. R. Hansen, R. K. Hose, P. B.King, Hal T. Morris, S. S. Oriel, and C. A.Wallace. We are grateful also to C. A. Ander-son, K. C. Condie, A. J. Eardley, and S. S.Oriel, for critical review of the manuscript,and to R. W. Kopf fot his painstaking atten-tion to geologic names.

REFERENCES CITED

Anderson, A. L. Portland cement materialsnear Pocatello, Idaho: Idaho Bur. MinesGeol., Pamph. No. 28, 15 p., 1928.

Armstrong, R. L. The Sevier orogenic belt inNevada and Utah: Geol. Soc. Amer., Bull.,Vol. 79, p. 429-458, 1968.

Bick, K. F. Geology of the Deep Creek Moun-tains, Tooele and Juab Counties, Utah:Utah Geol. Mineralog. Surv., Bull. 77, 120p., 1966.

Blackwelder, Eliot. New light on the geologyof the Wasatch Mountains, Utah: Geol.Soc. Amer., Bull., Vol. 21, p. 517-542;map, p. 767, 1910.

Bright, Robert C. Geology of the Cleveland




area, southeastern Idaho: M.S. thesis, UtahUniv., Salt Lake City, Utah, 262 p., I960.

Butler, B. S.; Loughlin, G. F.; Heikes, V. C;and others. The ore deposits of Utah:U.S. Geol. Surv., Prof. Pap. Ill, 672 p.,1910.

Calkins, F. C.; and Butler, B. S. Geology andore deposits of the Cottonwood-AmericanFork area, Utah: U.S. Geol. Surv., Prof.Pap. 201, 152 p., 1943.

Christiansen, F. W. Structure and stratigraphyof the Canyon Range, central Utah: Geol.Soc. Amer., Bull., Vol. 63, No. 7, p. 717-740, 1952.

Cohenour, R. E. Sheeprock Mountains, Tooeleand Juab Counties: Utah Geol. Mineralog.Surv., Bull. 63, 201 p., 1959.

Compton, R. R. Thrusting in northwest Utah[abstr.]: Geol. Soc. Amer. abstr. 1969 (RockyMountain Sect.), p. 15, 1969.

Condie, K. C. Late Precambrian rocks of thenortheastern Great Basin and vicinity: J.Geol., Vol. 74, No. 5, Part. 1, p. 631-636,1966.

Condie, K. C. Geologic evolution of the Pre-cambrian rocks in northern Utah and ad-jacent areas: Utah Geol. Mineralog. Surv.,Bull. 82, p. 71-95, 1969.

Crittenden, M. D., Jr. Magnitude of thrustfaulting in northern Utah, Art. 335: U.S.Geol. Surv., Prof. Pap. 424-D, p. D128-D131, 1961.

Crittenden, M. D., Jr. Geology of the Drome-dary Peak quadrangle, Utah: U.S. Geol.Surv., Map GQ-378, scale 1:24,000, 1965a.

Crittenden, M. D., Jr. Geology of the MountAire quadrangle, Salt Lake County, Utah:U.S. Geol. Surv., Map GQ-379, scale1:24,000, 1965b.

Crittenden, M. D., Jr. Younger Precambrianand basal Cambrian rocks near Huntsville,Utah [abstr.]: Geol. Soc. Amer. abstr. 1967(Rocky Mountain Sect.), p. 29-30, 1967.

Crittenden, M. D., Jr.; Sharp, B. J.; andCalkins, F. C. Geology of the WasatchMountains east of Salt Lake City, ParleysCanyon to Traverse Range: in Geology ofthe central Wasatch Mountains, Utah (R.E. Marsell, ed.), Utah Geol. Soc., Guide-book No. 8, p. 1-37, 1952.

Eardley, A. J. Geology of the north-centralWasatch Mountains, Utah: Geol. Soc.Amer., Bull., Vol. 55, No. 7, p. 819-894,1944.

Eardley, A. J. Major structures of the RockyMountains of Colorado and Utah: UMR,J., No. 1, University of Missouri at Rolla,p. 79-99, 1968.

Eardley, A. J. Willard thrust and the Cacheuplift: Geol. Soc. Amer., Bull., Vol. 80,No. 4, p. 669-680, 1969.

Eardley, A. J.; and Hatch, R. A. Proterozoic

(?) rocks in Utah: Geol. Soc. Amer., Bull.,Vol. 51, p. 795-844, 1940.

Felix, C. E. Geology of the eastern part of theRaft River Range, Box Elder County,Utah: in Geology of parts of northwesternUtah (A. J. Eardley; and G. T. Hardy, ed.),Utah Geol. Soc., Guidebook to the geologyof Utah, No. 11, p. 76-97, 1956.

Flint, R. F.; Sanders, J. E.; and Rodgers, J.Diamictite, a substitute term for symmic-tite: Geol. Soc. Amer., Bull., Vol. 71, No.12, p. 1809, I960.

Frakes, L. A.; and Crowell, J. C. Late Paleo-zoic glaciation: I. South America: Geol.Soc. Amer., Bull., Vol. 80, p. 1007-1037,1969.

Giletti, B. J.; and Gast, P. W. Absolute ageof Pre-Cambrian rocks in Wyoming andMontana: in Geochronology of rock sys-tems, N. Y. Acad. Sci., Ann., Vol. 91,Art. 2, p. 454-458, 1961.

Goddard, E. N.; and others. Rock colorchart: Nat. Res. Council, Washington,D.C., 1948 (reprinted by Geological So-ciety of America, 1963).

Groff, S. L. Geology of the West Tintic Rangeand vicinity, Tooele and Juab Counties,Utah: Ph.D. dissert., Utah Univ., Salt LakeCity, Utah, 1959.

Hansen, W. R. Absolute age of the Red CreekQuartzite (Precambrian) exceeds 2 billionyears [abstr.]: Geol. Soc. Amer. abstr. 1963(Rocky Mountain Sect.), p. 274-275, 1963.

Hansen, W. R. Geology of the Flaming Gorgearea, Utah-Colorado-Wyoming: U.S. Geol.Surv., Prof. Pap. 490, p. 1-196, 1965.

Harris, DeVerle. The geology of Dutch Peakarea, Sheeprock Range, Tooele County,Utah: Brigham Young Univ., Res. Studies,Geol. Ser., Vol. 5, No. 1, 82 p., 1958.

Hewett, D. F. Geology and mineral resourcesof the Ivanpah quadrangle, California andNevada: U.S. Geol. Surv., Prof. Pap. 275,172 p., 1956.

Hintze, F. F., Jr. A contribution to the geologyof the Wasatch Mountains, Utah: N. Y.Acad. Sci., Ann., Vol. 23, p. 85-143, 1913.

Hintze, L. F. Geologic map of Utah, southwestquarter: Utah Univ., College Mines Min.Ind., Salt Lake City, Utah, 1963.

Larsen, W. N. Petrology and structure ofAntelope Island, Davis County, Utah: Diss.Abstr., Int., Vol. 17, No. 9, p. 2025-2026,1957; Geol. Soc. Amer., Bull., Vol. 68,No. 12, Part. 2, p. 1866-1867, 1957.

Lochman-Balk, Christina. Cambrian statigra-phy of the south and west margins ofGreen River Basin [Utah-Wyoming]: inWyo. Geol. Ass., Guidebook, 10th Ann.Field Conf., p. 29-37, 1955.

Lowden, J. A. Isotopic ages, Rept. 2 of Agedeterminations by the Geological Survey



REFERENCES CITED 601

of Canada: Can. Geol. Surv., Pap. 61-17,127 p., 1961.

Ludlum, J. C. Pre-Cambrian formations atPocatello, Idaho: J. Geol., Vol. 50, No. 1,p. 85-95, 1942.

Ludlum, J. C. Structure and stratigraphy of partof the Bannock Range, Idaho: Geol. Soc.Amer., Bull., Vol. 54, No. 7, p. 973-986,1943.

Mansfield, G. R. Geography, geology, andmineral resources or the Fort Hall Indianreservation, Idaho: U.S. Geol. Surv., Bull.713, 152 p., 1920.

Mansfield, G. R. Geography, geology, andmineral resources of part of southeasternIdaho: U.S. Geol. Surv., Prof. Pap. 152,p. 1-409, 1927.

Mansfield, G. R. Geography, geology, andmineral resources of the Portneuf quad-rangle, Idaho: U.S. Geol. Surv., Bull. 803,110 p., 1929.

Obradovich, J. D.; and Peterman, Z. E.Geochronology of the Belt Series, Montana:Can. J. Earth Sci., Vol. 5, p. 737-747, 1968.

Oriel, S. S. Brigham, Langston, and Ute For-mations in Portneuf Range, southeasternIdaho [abstr.]: Geol. Soc. Amer. abstr. 1965(Rocky Mountain Sect.), p. 341, 1965.

Rigo, R. J. Middle and Upper Cambrianstratigraphy in the autochthon and alloch-thon of northern Utah: Brigham YoungUniv., Geol. Studies, Vol. 15, Part, 1, p.31-66, 1968.

Staatz, M. H.; and Carr, W. J. Geology andmineral deposits of the Thomas and Dug-way Ranges, Juab and Tooele Counties,Utah: U.S. Geol. Surv., Prof. Pap. 415,188 p., 1964.

Stokes, W. L. Geologic map of northwesternUtah: Salt Lake City, Utah, Geol. Miner-

alog. Surv., scale 1:250,000, 1963.Trimble, D. E.; and Schaeffer, F. E. Stratigra-

phy of the Precambrian and Lower Cam-brian rocks of the Pocatello area, Idaho[abstr.]: Geol. Soc. Amer. Abstr. 1965, p.349, 1965.

Walcott, C. D. Cambrian geology and paleon-tology: Smithson. Misc. Collect., p. 1-431,1908a.

Walcott, C. D. Cambrian sections of the Cor-dilleran area: in Cambrian geology andpaleontology, Smithson. Misc. Collect.,Vol. 53, No. 5, 1908b.

Walker, J. F. Geology and mineral deposits ofthe Windermeremap area, British Columbia:Can. Geol. Surv., Mem. 148, 69 p., 1926.

Williams, J. S. Geologic atlas of Utah-CacheCounty: Utah Geol. Mineralog. Surv.,Bull. 64, 104 p., 1958.

Woodward, L. A. Stratigraphy and correlationof late Precambrian rocks of Pilot Range,Elko County, Nevada, and Box ElderCounty, Utah: Amer. Ass. Petrol. Geol.Bull., Vol. 51, No. 2, p. 235-243, 1967.

Woodward, L. A. Lower Cambrian and upperPrecambrian strata of Beaver Mountains,Utah: Amer. Ass. Petrol. Geol. Bull., Vol.52, No. 7, p. 1279-1290, 1968.

Yates, R. G. The Trans-Idaho discontinuity, amajor tectonic feature in northwesternUnited States [abstr.]: 23rd Intetnat. Geol.Cong., Prague, Czechoslovakia, 1968, Ab-stracts, p. 38, 1968.

MANUSCRIPT RECEIVED BY THE SOCIETY MAY4, 1970

REVISED MANUSCRIPT RECEIVED OCTOBER 21,1970

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