UNITED STATES DEPARTMENT of TIlE INTERIOR 


Harold L. Ickes, Secretary 


GEOLOGICAL SURVEY 

W. C. Mendenhall. Director 

Professional Paper 177 

THE GOLD HILL MINING DISTRICT 


U'TAH 


BY 

T. B. NOLAN 

UNItED STATES 


GOVERNMI£NT PRINTING OFFICE 


WASHINGTON: 1935 


For sale by the Superintendent of Docnmente, Washington, D.C. - - - - - - - - - - - - - - - - - - - - - - - - • - - - l'flC< $1.25 
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CONTENTS 


AbstracL_________________ _ 

Introduction _ _ _ _ _ _ _ _______________ _ 

Location and accessibility ____________ _ Geography_____ _ _______________ _ 

Physical features____ _ _ _ _ _ __ _ _______ _ 

Climate and vegetation_ _ _ _ _ _________ _ 

Field work and acknowledgments_ _ __________ _ Previous work____ ______________ _ 

Present work_____ _ _ _____________ _ 

Geologic formations_ _ _ _______________ _ 

Cambrian system_ _______________ _ 

Prospect Mountain quartzite_ Cabin shale_ _ _ _ _ ____ _____ _ __________ _ 

Busby quartzite_ ____ ____ 

Abercrombie formation_ 

Young Peak dolomite_ 

Trippe limeatone____ 

Lamb dolomite 

. ___________ _ 

Hicks formation __________________ _ 

Unconformity at top of Upper Cambrian ____ _ Ordovician system_ _ _ _ _ _ _ _ _ _ _______ _ 

Chokecherry dolomite _ ________ _ 

Unconformity at base of Upper Ordovician___ _ Fish Haven dolomite_____________________ _ 

Unconformity at top of Upper Ordovician____ _ Silurian system_ _ ____________ _ 

Laketown dolomite____________ _ 

Unconformity between Silurian and Devonian_ 

Devonian system_ __ _ _ __ _________ _ 

Sevy dolomite_ _ _ _ _ _ _ __________ _ 

Simonson dolomite___ ___________ _ 

Guilmette formation_ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

Unconformity at base of Carboniferous ____ _ 

Origin of the pre-Carboniferous dolomitic formations_ 

Correlation of pre-Carboniferous sedimentary rocks 

in eastern Nevada and western Utah __________ _ 

Carboniferous system____ __ __ _ _ _ ________ _ 

Madison limestone___ __ _ _ _________ _ 

Woodman formation __ 

Ochre Mountain limestone _.. __________ _ 

Manning Canyon formation _____ ... ___ _ 

Mississippian-Pennsylvanian contact_ __ 

Oquirrh formation________ _______ _ 

Gerster formation___ _ _ ____________ _ 

Correiation of the Carboniferous formations __ Lower Triassic limestones___ _ __________ _ 

Unconformity at the base of the Eocene (?) _____ _ Tertiary system_ _ _____________________ _ 

White Sage formation ________________ _ 

Unconformity above White Sage formation ____ _ 

Older igneous rocks ___ _ General features ____________________ _ 

Quartz monzonite__ _ 

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Geologic formations-Continued. 

Tertiary system-Continued. 

Older igneous rocks-Continued. 

Porphyry dikes_ _ _ _ _____________ _ 46 

Aplite dikes_ _ ___________________ _ 48 

Age of the older igneous rocks __________ _ 48 

Pliocene(?) sediments ___________________ _ 48 

Younger igneous rocks ______ _ 49 

Distribution and relations___ _ 49 

Petrography_____ _ _ _ _ _______ _ 49 

Biotite and hornblende andesites or latites_______ ___________ _ 50 

Hypersthene-augite latite _____ _ 50 

Trachyte_ _ _________ _ 51 

Rhyolites ________________ _ 51 

Alkali basalt__________ _ 52 

Pyroclastic rocks_____ _ 52 

Alteration of the volcanic rocks_________ _ 53 

Age of the volcanic rocks ______________ _ 53 

Gravel and clay____ __ _ _ ___________ _ 53 

Older gravel and clay__________________ _ 54 

Younger gravel and clay_______________ _ 54 

Lake Bonneville beds__________________ _ 54 

Geologic structure_ _ ____________________________ _ 55 

Structural cycles_____________ _________ _ 55 

First cycle_ _ _ _ _ ___ _ _ _ _ _ __________ _ 55 

Second cycle __ _ _ _ _ _ _ _ _____________ _ 55 

Third cycle _ _ _ _ _ _ _ _____________ _ 56 

Fourth cycle_ _ _ _ __________________ _ 58 

Fifth cycle and faults related to the quartz 

monzonite intrusion ___________ _ 60 

Progressive variation in the character of deformation_ _ _ ______ ___ ____ __ __ _ ______ _ 60 

Late normal faulting and its relation to the present topography_________ __________________ _ 61 

Age of the structural featurea___________________ _ 63 

Local descriptions_____ _____________________ _ 64 

Deep Creek Mountain block. ______________ _ 66 

Uiyabi Canyon block ________ _ 69 

Ochre Mountain block_______ _ ________ _ 72 

Dutch Mountain block______ _ _________ _ 78 

Northwestern block_ _ ___ _ ____________ _ 85 

Quartz monzonite block_ _________ _ 88 

Igneous metamorphism___________________________ _ 91 

Alteration of the sedimentary rocks _______ _ 91 

Recrystallization_______________________ _ 91 

Alteration to silicate minerals__ 92 

Alteration to jasperoids______ _ 93 

Dolomitization ___________________________ _ 94 

Alteration of the quartz monzonite______________ _ 94 

Diopside-orthoclase alteration ____________ _ 94 

Sericitization and chloritization_______ _ 95 

Silicification___ _______________ _ 95 

m 
CONTEN'.I'S 

Igneous metamorphism-Continued. 

Comparison of the alteration of the sedimentary 

rocks and the quartz monzonite______________ _ Ore dpposits_. ________________________________ _ 

Classification______ - ________________ - -- - --

Pipelike deposits__ _ _ _ _ _ _ _ _ _ _ _ _ _ ______________ _ 

Veins with silicate minerals in the gangue________ _ 

Veins containing chiefly quartz and metallic sulphides_______ _ __ _ ________________ -- -­

Veins with carbonate or sulphate minerals in the 

gangue _ _ _ _ _ _ _ _ ___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

Arsenic replacement bodies______________ 

Copper-lead-silver replacement bodies_ _ _ 

Superficial alteration of the ores_ _ _ _ _ _ _ _ _ _ 

Relation of the water table to superficial alteration _________________________ 

Relation of the physical and chemical character of the ores to superficial alteratioll_ _ __ _ 

Areal relations of the ore deposits_ _ _ _ _ _ _ _ _ _ _ _ _ _ 

Influence of zoning on the distribution of the ore deposits_ _ _ _ _ _ _ _ _ _ _ _ _ _____ _ _ _ _ 

Influence of the Ochre Mountain thrust on the 

distribution of the ore deposits _ _ _ _ _ _ _ _ _ _ 

Genesis of the ore deposits_ _ _ _ _ _ _ _ _ _ _ _ _ 

Future of the districL________________________ _ 

Tungsten-bearing pipes and veins_ ___ _ _ _ _ _ _ _ 

Veins with silicate minerals in the gangue_____ 

Quartz-sulphide veins _ _ ___ _ _ _ _ _ _ 

Carbonate-sulphate veins ___________,. ___ _ _ 

Arsenic replacement bodies_ ___ _ _ _ _ _ _ _ _ _ 

Copper-lead-silver replacement bodies _ _ _ _ _ _ _ _ Summary___________________ _____________ 

Minerals of the metamorphosed rocks and the ore depo~ts_______ _ _________ __________ ________ 

Native elements_ ______________________ _ 

Sulphides, selenides, tellurides, arsenides, and antimonides_______________________ __ _______ 

Sulphosalts____ _ _ _ _ _ _ _ __ ___ __ _____ _ _ _ _ _ ___ _ 

Haloids___ __ _ _ _ _ __ _ _ ____ _ _ __ __ __ ____ 

Oxides______ _ ___________ __________________ 

Carbonates_ ___ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ __ __ _ _ 

Silicates __ _ _ _ _ _ _ _ _ __ __ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ 

Titanosilicates____ _ _____ ________ __ _ 

Phosphates, arsenates, vanadates, and antimonates_ 

Sulphates, chromates, and tellurates_____ _ _ _ _ _ __ _ _ 

Tungstates and molybdates________ ________ 

Mines and prospects_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

Clifton district _ _ __ _ _ _ _ __ _ _ _ _ __ _ _ _ _ _ _ _ 

History of mining and production__ ___ _ _ _ _ _ _ 

Mines and prospects____ ___________ __ _ 

Pipelike deposits _____________ . __ ___ _ _ _ _ 

Reaper__________________ ________ 

Yellow Hammer_ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ 

Doctor. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

CentenniaJ and Enterprise_ _ _ _ _ _ _ _ _ _ 

Veins with silicate minerals iii the gangue_ Frankie_ __ _ _ _ _ _ _ ___ _ _ _ __ _ _ _ _ _ _ _ _ _ 

Calaveras_ _______________ _______ 

Pole Star Copper Co_______ _ 

Copperopolis (Ida Lull) _ _ _ _ _ _ _ _ _ _ _ _ _ 

Napoleon Mining Co_________ __ __ Gold Bond_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ 

Copper Bloom_ __ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ 

Victory No. L _ _ ___ _ _ _ _ _ _ _ _ _ _ _ _ _ __ 

Minnehaha________________________ 

Ozark____________________________ 

Copper Hill_______________________ 

Alvarado_________________________ 

Page II 


Mines and prospects-Continued. 


Clifton district-Continued. 


96 
 Mines and prospects-Continued. 


97 
 Veins with silicate minerals in the gangue97 
 Continued. 


97 
 Cane Springs_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _____ _ 1 


n4idas _________________________ _ 99 
 1 


Bonnemort_______________________ _ 1
 Rube____________________________ _ I: 

Wilson Consolidated ______________ _ 101 


Ii 

101 
 Veins containing chiefly quartz and metaJlic sulphides___ __ __ __ __ ___ __ __ _ _ _ _ _ _ 14
 102 


Lucy L_____ _________________ 14' 

Boston ___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 14: 

103 


104 


New York. _________ _ __________ 14i 


104 
 Silver & Gold Mining Co____________ 14:i 


Mascot_____________________ ._ _ 143 


Monte del Rey _ _ _ _ _ _ 144 


107 


105 


Fortuna_______ ____ _ _________ 144 


Bonanza._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 144 


107 
 Cyclone ____ ._ _ _ _ _ _ _ _ _ _ _ _ _ 144 


Success________ __________________ 145 


108 
 Spotted Fawn_ _ _ _ _ __ ____ _ _ _ _ _ _ __ _ _ 145 


108 
 Western Utah Extension Copper Co__ 146 


Climax _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 147
 109 


109 
 Southern Confederate_____ ______ _ 147 


109 
 Red JackeL_______________________ 148 


110 
 Copper Queen Midland Mining Co___ 148 


110 
 Cash Boy (Mammoth)_____ _______ 148 


110 
 New Baltimore_ ___ _ _ _ _ _ _ _ _ _____ ___ 149 


110 
 Bird________________________ _ ___ 149 


110 
 Shay___ _______________________ 149 


Gold Hill Standard Mining Co_ _ _ _ _ _ 149 


110 
 Gold Belt_ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ 149 


110 
 Pay Rock______________________ __ 150 


Undine _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 150 


111 
 Rea_____ _ _________________ .__ 150 


111 
 Christmas Mining Co______________ 151 


112 
 Veins with carbonate or sulphate minerals 

112 
 in the gangue________ _ _____________ 151 


112 
 Troy_________________________ ___ 151 


113 
 Immense_______ _ _ _ __ _ _ ___ ____ ___ __ 151 


116 
 Arsenic replacement bodies______________ 151 


116 
 Gold Hill mine of Western Utah 


117 
 Copper Co__ ___ __ ___ ___ __ _____ _ _ 151 


117 
 Gold Hill mine of United States Smelt118 
 ing, Refining & Mining Co________ 156 


118 
 Oregon_____ ___________ _ _______ 162 


118 
 IIerat_________________ _________ 162 


119 
 Copper-lead-silver replacement bodies_ _ _ _ 162 


119 
 Monocco______________ _ _________ 162 


119 
 Silver King ___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 163 


122 
 Mohawk___ _ _ ___ ______ __ _ _ _ _ _ __ _ _ 163 


122 
 Walla Walla______ __ ___ ___ __ _ __ _ _ 164 


122 
 Garrison Monster Mining Co_ 164 


123 
 Consolidated claim_ _ _ _ _ _ _ _ _ _ _ _ _ 164 


123 
 New Year claim______ __ __ ___ 166 


124 
 Uncle Sam claim________ ._ _____ 166 


124 
 Evans__________ _________________ 166 


125 
 Willow Springs district. ____ _ _ _ __ ___ _ _ _ _ _ ___ 167 


125 
 History and production_________ .... __ _ 167 


125 
 Prospects_ _ _ _ _ _ _ _ _ _ _ 167 


127 
 Dewey______________ __________ 167 


127 
 Sunday___ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ 167 


127 
 Lead-Carbonate_______________ _______ 167 


128 
 Silver. _ _ _ _ _ _ _ _____ ___ _ __ ___ ___ ____ __ 168 


128 
 Other prospects_ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 168 


128 
 Index____________________________________________ 169 

ILLUSTRATIONS 


Faile 

PLATE 1. Geologic map and sections of the Gold Hill 

quadrangle, Utah___ ________ In pocket 

2. 	 Geologic map and sections of Gold Hill and 

vicinity__________ ____ _ In pocket 

3. Fault map of the Gold Hill quadrangle __ In pocket 

4. 	 A, Bonneville beach and spit, southeast of 

Dutch Mountain; B, Dutch Mountain from 

the southeast; C, Clifton Flat from the 

southwest____ ____ 	 8 

5. 	 A, Mottled Young Peak dolomite; B, Laminated Trippe limestone; C, Pisolitic dolomite from the Hicks formation; D," Marble cake" dolomite near the base of the 

Laketown dolomite; E, Laminated Simonson dolomite; F, Chert-pebble conglomerate with oolitic matrix from Oquirrh 

formation_ ___ 8 

6. 	A, East slope of Ochre Mountain; B, Dissection on west slope of Ochre Mountain; C, 

D, Dissected postmaturc erosion surface___ 64 

7. 	 A, Crumpling beneath nearly fiat fault on the 

west side of Ochre Mountain; B, Plunging 

minor anticline in the Manning Canyon 

formation; C, Variable dip of fault hetween 

the Madison limcstone and the Woodman 

formation ill Accident Canyon; D, Minor 

thrust in the ·Woodman formation north of 

the Garrison Monster new camp _.. tl4 

8. 	 A, \Vollastonite replacing garnet in metamorphosed Ochre Mountain limestone; B, 

Jasperoid from the U.S. mine, with inclusions of opal in quartz; C, Wollastonite 

rcplaced by spadaite; D, Preservation of 

calcite cleavage lines in jasperoid_ __ _ 96 

9. 	 A, Elongated quartz grains in silicified quartz 

monzonite; B, Successive replacements in 

a specimen from the tungsten-bearing pipe 

on the Reaper claim; C, Apatite and molybdenite in amphibole_ _____ _ _ _ 96 

10. 	 A, ReplACement of specularitc hy danburfte 

and fluorite, Gold Bond claim; B, Rcplacement of tourmaline by specularite, Gold 

Bond claim; C, Quartz carbonate vein, 7,000 

feet east of Clifton; D, Quartz and orthoclase replacing calcite, Wilson Consolidated 

mine; E, Polished section showing arsenopyrite fragments cemented by other sulphides and quartz, Cyclone mine___ 104 

11. 	 A, Bladed arsenopyrite, Tunnel level, U.S. 

mine; B, Polished section showing brecciated arsenopyrite veined by pyrite, quartz, 

sphalerite, and galena, U.S. mine; C, Polished section showing replacement of arsenopyrite fragments by quartz and sericite, 

Western Utah mine; D, Thin section showing barite replacing sulphides, Garrison 

Monster mine____ ____ _ _ _ ___ _ _ _ _ __ ____ 104 

Page 

PLATE 12. A, Dense white scorodite with associated 

crystalline grecn scorodite, Western Utah 

mine; B, Brown scorodite, Western Utah 

mine; C, Crystalline scorodite forming 

from metacolloid _ _ _ _ _ _ ___ _ 104 

13. Plan of workings, Lucy L mine ___ _ 140 

14. Block diagram of Gold Hill mine of Western 

Utah Copper Co ___________ . _________ _ 152 

15. Level map of Gold Hill mine of Western Utah 

Copper Co __ _ _ _ __ _ _ __ _ _______ _ 152 

FIGURE 1. Index map of Utah showing location of 

Gold Hill q uadrangle___ _ 1 

2. Sections of the Young Peak dolomite, showing the interfingering northward of limestone________________ ____________ _ 10 

3. 	Correlation of pre-Carboniferous rocks in 

eastern Nevada and western Utah from 

west to east_ _______________________ _ 24 

4. Correlation of pre-Carboniferous rocks in 

eastern Nevada and western Utah from 

north to south _________ .. _____ _ 25 

S. 	 Relations between the three facies of the Carboniferous rocks _____________________ _ 26 

6. 	Correlation of Carboniferous formation in an 

east-west belt from Eureka, Nev., to the 

Cottonwood-Park City area, Utah ____ _ 40 

7. 	 Correlation of Carboniferous formations in 

a northeast-southwest belt from Pioche, 

Nev., to the Randolph quadrangle, Utah_ 41 

8. Block diagram showing the generalized structure along the Garrison Monster trans­ verse fault _______ _ 60 

9. 	Crumpling of Guilmette formation north of 

Lincoln Highway__ _ _ __ __ _ _ ____ ___ _ 70 

10. 	Sketch map showing folding of a bed in the 

Oquirrh formation on the northwest side 

of Dutch Mountain _ ___ 85 

11. Generalized 	section showing supposed original relations between the Twin Peaks recumbent anticline and the Dutch Mountain thrust__ 86 

12. 	Strikes and dips of various types of fractures 

in the quartz monzonite_____ _ ______ _ 90 

13. Plan of main workings, Reaper claim____ _ 120 

14. Prospect pits and mineralization adjacent to 

Reaper open cut ____________________ _ 121 

15. Plan of adit tunnel, Copperopolis group___ _ 126 

16. Plan of Alvarado mine workings ___ _ 129 

17. Geologic cross section through Alvarado 

shaft _ _ _ _ 	 __ __ _ _ _ __ 129 

18. 	Stope projection on plane through shaft, Alvarado mine.____ .. ___________ _ 130 

19. Plan of Cane Springs mine workings.. _____ _ 132 

20. Composite section through Cane Springs mine_______________________________ _ 133 

21. Stope projection, Cane Springs mine__ _ ___ 133 

22. Plan of tunnel level, Midas mine___ _ 134 

23. 	 Plan of mine workings, Rube mine_ 137 

v 
VI ILLUSTRATIONS 

Page Page 

FIGURE 24. Longitudinal section through Rube mine__ _ 

25. Sketch plan and section of W lson Consoli137 FIGURE28. Plan of tunnel level, Western Utah Extension Copper Co__ _ _____________ _ 146 

dated mine ___ _ 139 29. Plan of workings, U.S. mine _____________ _ 157 

26. Cross section of Lucy L mine_ _ _ _____ _ 141 30. Section through adit tunnel, U.S. mine____ _ 159 

27. Plan of t,unnel and surface workings on north 

side of gulch, Spotted Fawn mine ______ _ 145 

31. Mine workings on Consolidated claim, Garrison Monster mine___________________ _ 165 

--~.---,.~ 
ABSTRACT 


lntroduction.-The Gold Hill quadrangle is in west central 

Utah and is limited by parallels 40° and 40°15' and meridians 

113°45' and 114°. This area includes the norlh end of the 

Deep Creek Mountains, one of the ranges in the Great Basin. 

The climate of the region, like that of the major province, is 

relatively arid, the average annual rainfall being about 13 

inches. 

Geologic !ormations.-The following stratigraphic sequence is 

described: 

Thickness System I Series i Formation (feet) 

'lRecent to Pliocene? ---' Gravel and'O~la~y~.•~.~..~.-..-.1 

Quaternary and Unconformity. Tertiary. Pliocene (1) •.•••• -,•••• Gravel and marL ....... Unconformity.


Eocene (?) ............• White Sage formation ... 
 Unconformity. 
 50 Triassio•...__ ••.. j~~;;:;fa~~~~."!~::::: ::::i t~~~~°l:,~maiion::: :::: 600 Permian and Pennsyl· Oquirrh formation ... __ . ±8,OOO

vanian, ,. Pennsylvanian (Potts- Manning Canyon for· ±5oo 

Carbomferous_.,. ville) and Mississip- mation, 

pian (?). . oehre Mountain lime­ ±4,5oo MI ' . . J stone. ,- SSlssIPplan-· ..··.... lWOOdman formatlon_ ... ±I,5oo . Madison limestone ...... (Hoo

lJnoonformity, 

JGllilmette formation ...• 900-1,200 

Devonian...._... Middle Devonian...._. [Simonson dolomite ....__ 1,000 Sevy dolomite __...____ __ 450 lJncontormity. Silurlan___________ ._ .. __ ..... ____ ".. _.._.. Laketown (lolomite .. __ . ±I,OOO 

uppex Ordovician____ Fish Haven dolomite ... 250 Or<lovlcian____ . _, Unconformity. {

,	Lower Ordovician .... __ Chokecherry dolomite.' ±(}-I,OOO 

Unconformity.. uppor Cambrian....... {HickS format!on ____ . __ .. 600-1,200 Lamb dolomIte....____ . 1,050 I Trippe Iimestone.._____ . 725 j Cl¥llbriall..•__ •.' Middle Call1briall.... __ rg~~Jo~gfe ~~~:;.\\~n: ~8& {Busby quartzlte________ • 450 

Low r C mb i n {Cabin shale _____ . ____ .__ 510 ear a ....--. Prospect Mountain ±3,000-4,750 

quartzite. 

The considerable thickness of dolomites found in the preCarboniferous sequence is noted, and it is suggested that much 

of the dolomite in the area has been formed by the alteration 

of an original limestone shortly after its deposition in shallow 

waters in which little or no additional deposition was possible. 

Three facies of Carboniferous rocks were recognized, which 

are separated from each other by two major thrust faults. The 

three facies differ from one another in lithology and in the 

thickness of certain of the formations. 

An intrusive stock of quartz monzonite is of early Tertiary 

age. Variations in composition ranging from that of granite to 

one approaching diorite ean be recognized, but no sharp 

boundary was found between these different phases. The 

boundaries of the stock in several places show a dependence 

upon preexistent faults, but the intrusion itself appears to 

have caused essentially no deformation in the invaded rocks. 

The limitation of the stock to the region between two major 

transverse faults that also limit one of the major overthrusts may 

be due to the more thorough shattering of the area thus enclosed 

and the consequent greater ease in the emplacement of the 

magma. 

Numerous porphyry dikes associated with the intrusion show 

an almost complete gradation between granite porphyries in 

which the groundmass has an allo.triomorphic texture to basalt 

dikes in which the groundmass is characterized by an intergranular texture. Aplite dikes in the quartz monzonite are 

younger than the porphyry dikes. 

A younger series of igneous rocks is composed almost entirely 

of flows and pyroclastic rocks. The bulk of the material is 

andesitic in appearance, but chemical analysis of typical 

specimens proved them to be of latitic or trachytic composition. 

One flow, partly glassy, contained 8.90 percent of K20, although 

no potash-bearing feldspar was recognized under the microscope. Small outcrops of basaltic-appearing rocks also proved 

to be notably high in potash. These rocks are thought to be of 

late Pliocene age. 

Geologic slructure.-The structural history of the quadrangle 

is characterized by at least four and possibly five cycles of 

folding and faulting, each cycle composed of an initial stage in 

which compressiv!t forces were active and a final stage in which, 

normal faulting was dominant. 

The structural features of the first cycle are naturally obscure, 

but there appears to have been an early stage of relatively 

minor thrusting, succeeded by rather intense normal faulting. 

During the first stage of the second cycle numerous folds, of 

which at least one was recumbent, and minor thrusts were 

formed, apparently nnder a moderately thick cover. The 

second stage of the second cycle is represented by a small number 

of normal fanlts, the t.hrows along which are generally several 

thonsands of feet. The third cycle was initiated, after a prolonged period of erosion, by a long phase of thrusting and 

transverse fanlting, which must have, occurred under a very 

llght load. One of the two major thrusts of this stage was 

originally limited between two transverse faults, and associated 

with both of the thrusts are relatively narrow ihrust sheets. 

Considerable evidence is available that these thrusts, in the 

i 	 regions now exposed, moved over the then existing surface. 

The normal faulting at the end of this cycle was relatively 

sUght, and much of it appears to have taken place along preexistent faults. The early stage of the fourth cyole was oharaeI 	 terized by numerous transverse faults with an almost complete 

lack of folding and thrust faulting. Unusually complex minor 

structural features are associated with some of the larger transverse faults. Normal faults that should belong to the final 

stage of this cycle appear to be almost completely lacking. 

These four cycles antedate the intrusion of the quartz monzonite, and a possible fifth cycle is indicated by minor thrust 

faults that cut the intrusive. 

It is suggested that the successive dominallce of folding, 

thrusting, and transverse faulting in the initial stages of 

progressively younger cycles is genetically connected with the 

fact that these structural processes occurred under a constantly 

decreasing load. If it may be assumed that normal faults are 

the result of relaxational movements after excess compression, 

the apparent decrease in the importance of normal faulting 

throughout the period of deformation may be attributed to the 

progressively greater resistance of the rocks within the quadrangle as a result of the successive periods of compression. 

VII 
vm ABSTRACT 

Recent normal faults displace an old postmature erosion 

surface that bevels all the older structural features. Evidence 

is presented that these faults are not all strictly contemporaneous, that the faulting tended to utilize older fault lines, and 

that both walls of individual faults have been active. 

The structural features of the third cycle appear to be more 

or less contemporaneous with the deposition of the Eocene 

White Sage formation. The two previous cycles are considerably older, becau.se a period of erosion must have intervened 

between them and the third cycle, and a Cretaceous age is 

therefore suggested for them. The relatively recent normal 

faults are probably of late Pliocene age. 

Igneou8 metamorphism.-The sedimentary rocks near the 

quartz monzonite have been more or less affected by the 

intrusion. Four kinds of alteration were recognized-one 

involving recrystallization, one in which silicate minerals were 

introduced, one in which silicification occurred, and one in which 

limestones were dolomitized. These represent successive stages 

in the alteration. Similarly, three major stages of alteration ­

were recognized as having occurred in the quartz monzonite, 

after its consolidation-a diopside-orthoclase alteration, sericitization and chloritization, and silicification--each successively younger. The obvious similarities between the metamorphism of the sedimentary and intrusive rocks point to a 

common origin, at a stage that must have followed the consolidation of the portions of the intrusive now exposed. Differences in the metamorphism are explained chiefly by the 

different physical and chemical conditions existing in the two 

kinds of rock at the time of the alteration. 

Ore deposits.-The ore deposits show a very considerable 

range in character. For purposes of description the veinlike 

deposits have been divided into pipes, characterized by tungsten 

minerals in a pegmatitic gangue of hornblende, orthoclase, and. 

other silicates; veins with silicate minerals in the gangue, in 

which copper and gold are the valuable constituents and in 

which the content of the silicate minerals in the gangue may 

range from almost 100 percent to nearly zero; veins containing 

chiefly quartz and metallic sulphides, in which arsenic, lead, 

and silver are the chief metals found; and veins with carbonate 

or sulphate minerals in the gangue, which are at present of 

little or no economic importance. There are no very sharp 

boundaries between the successive members of this series of 

deposits, and veins that show gradations between two members 

of the series are abundant. In regions underlain by limestone, 

replacement bodies of arsenic ore and copper-lead-silver ore 

are found; and two of the arsenic ore bodies are -unusually 

large. Surficial alteration of the ore bodies has been relatively 

slight in the ore bodies with silicate minerals in the gangue, 

but is widespread in the other deposits. The arsenic replacement ore bodies have been particularly affected, the process 

resulting in the conversion of the primary arsenopyrite to 

scorodite. The bottom of the zone of complete alteration is 

considerably above the present water table, corrob;:ating the 

other evidence "Of relatively recent faulting. 

It is suggested that the lack of zonal distribution of the ore 

bodies is chiefly the result of recurrent fracturing in the intrusive throughout the period of ore deposition. A further factor 

that has inhibited the development of a zonal pattern in the 

ore deposits is the presence of one of the major overthrusts 

within the mineralized area. The rocks above the thrust are 

essentially barren, and it is thought that this is due to the 

inability of the ore-bearing fractures to penetrate the wide 

crushed zone that marks the fault. 

The several kinds of altered rock and of ore deposits and the 

relations that are exhibited between them lead to the suggestion 

that the fluids that cause igneous metamorphism and ore deposi. pass through a long series of changes that are comparable 

in If{gree to the changes produced by differentiation in many 

large intrusive masses. In this district many of these steps 

have been preserved by the recurrent fracturing to which the 

quartz monzonite has been subjected, and to this factor is 

ascribed the disappointingly small size of so many of the ore 

bodies. Only the gold lodes and arsenic replacement bodies 

are thought to have any great future importance. 

Brief notes are given on the 100 minerals recognized in the 

metamorphosed rocks and in the ore bodies. 

Mines and prospects.-The Clifton mining district, which lies 

within the quadrangle, is one of the oldest mining districts of 

Utah, having been organized in 1869. The value of its output 

of gold, silver, copper, lead, and zinc from 1901 to 1927, is more 

than $2,000,000, and in addition it- is estimated that about 

9,000 tons of metallic arsenic was contained in the ores shipped 

from the district during the period from 1920 to 1925. The 

northern part of the Willow Springs district is also included 

within the quadrangle, but the production from this source ill 

almost negligible. 

\ 
 t 5 
THE GOLD HILL MINING DISTRICT, UTAH 


By T. B. NOLAN 

INTRODUCTION 

LOCATION AND ACCESSIBILITY 

The Gold Hill quadrangle, in western Utah (fig. 1), 

is an area of 228 square miles enclosed between parallels 

40° and 40°15' and meridians 113°45' and 114°. The 

area has weekly train serVIce over the Deep Creek 

I 

I 

I 

110' 

---~--

1130 

lOgO 

J<'WURE I.-Index map of Utah showing locution of Gold Hill quadrangle and other areas covered by pub' 

lished Geological Surveyor other reports. 1, Gold Hill quadrangle; 2, Fairfield and Stockton quadrangles (Prof. Paper 173); 3, Bingham district (Prof. Paper 38); 4, Park City district (Prof. Paper (7); 

0, Cottonwood district (Bull. 620); 6, Randolph quadrangle (Am. Jour. Sci., 4th ser., vol. 36, 

pp. 406-416, 1913); 7, Tintic district (Prof. Paper 107); 8, San Francisco district (Prof. Paper 80); 9, 

Iron Springs district (Bull. 338). 

Railroad to Wendover, a division point on the Western Pacific Railroad. Gold Hill, the principal town in 

the area, with a population Qf about 60, is the southern terminus of the branch line. The Lincoln Highway passes through both Gold Hill and Ibapah, a 

small agricultural community in the southwest corner of the quadrangle. This highway, however, is 

relatively little used and in many places is in rather 

poor condition. About 40 miles of equally poor 

highway connects both towns with the Victory 

Highway at Wendover. 

GEOGRAPHY 

PHYSICAl, FEATURES 

The quadrangle includes the north 

end of the Deep Creek Mountains, one 

of the nearly north-south ranges that are 

common in the Great Basin. On the 

east and north the mountain area is 

separated by gravel slopes from the flat 

plain of the Great Salt Lake Desert, 

and on the west it is bounded by Deep 

Creek Valley and groups of irregular 

low hills. 

South of the southern edge of the 

quadrangle the Deep Creek Mountains 

have remarkably straight escarpments 

both on the east and the west. These 

persist for about 3 miles north of the 

quadrangle boundary. The distance 

between the two escarpments in this 

region is about 4 miles, and the area thus 

enclosed will be referred to in this report 

as the Deep Creek Mountains. 

The eastern escarpmllnt becomes less 

distinct to the north and in the latitude 

of Blood l\!Iountain disappears entirely. 

The western escarpment is more persistent and forms the western limit of 

the mountain region for nearly 12 miles 

within the quadrangle. To the north 

tilis escarpment forms the western 

border of a nearly rectangular elevated 

block known as Ochre Mountain, which 

is separated from the Deep Creek 

Mountains on the south by a westward-draining open valley through 

which the lincoln Highway passes and by the basinlike Clifton Flat, which drains to the southeast 

through Overland Canyon (pI. 4, G). 

- -._----._-.__._---­

1 
--

-- - --

---

2 GOLD HILL MINING DISTRICT, UTAH 

Overland Canyon may be taken as the boundary 

between the Deep Creek Mountains and the welldissected country to the north, which has been called 

the Clifton Hills. This region,. whose highest summit 

is Montezuma Peak, lies east of Clifton Flat and is 

limited on the east by a poorly defined but distinctly 

linear escarpment that is less than a mile west of the 

easter::t border of the quadrangle. East of the escarpment gravel-covered slopes lead down to the Great 

Salt Lake Desert. To the north the Clifton Hills 

merge westward with the Ochre Mountain mass and 

extend eastward beyond the escarpment in a series of 

low hills to the edge of the desert. 

At about the latitude of the town of Gold Hill the 

Clifton Hills by a gradual decrease in altitude pass 

northward into a wide belt of low-lying country which 

drains to the east. Farther north lies the rugged mass 

of Dutch Mountain (pI. 4, B), which rises abruptly 

from the Great Salt Lake Desert, in the northeast corner of the quadrangle. In this region also are some of 

the best exposures of the shore phenomena of the 

ancient Lake Bonneville (pI. 4, A). 

To the west Dutch Mountain decreases in altitude 

through a series of rude steps and merges with a hilly 

tract of country that lies north and northwest of Ochre 

Mountain. The escarpment that separates Ochre 

Mountain and the Deep Creek Mountains from Deep 

Creek Valley cannot be recognized in this region,which 

therefore marks the northern limit of the open find 

locally fiat-fioored portion of Deep Creek Valley. 

The only perennial stream within the area is the 

southern part of Deep Creek, which rises in the high 

mountains south of the quadrangle and flows northward through Deep Creek Valley along a course that 

closely parallels the 114th meridian. Owing to the 

demands of irrigation the stream is intermittent north 

of the Sheridan ranch. The ranches north of the Sheridan obtain water either from dug wells or from artesian 

wells. Several good-sized springs along the east side 

of Deep Creek V.alley provide water for stock and for 

the irrigation of a small area. The remainder of the 

quadrangle is very poorly supplied with water, the 

small quantities available being obtained from a few 

shallow wells and numerous small springs. The largest 

springs are the Ochre Springs, about 2 miles southwest 

of the town of Gold Hill, which furnish water for both 

the town and the mining operations. The water from 

these springs, like that from the other springs and wells 

in the mineralized area, has a high percentage of 

dissolved salts and is rather unpalatable. 

CLIMATE AND VEGETATION 

The Gold Hill quadrangle lies well within the region 

of interior drainage that includes western Utah and 

most of Nevada, and, like the rest of that province, 

it has an arid climate. Pronounced differences in 

temperature between night and day are characteristic, 

but the dryness of the air mitigates the high temperatures that often prevail during the summer afternoons. 

The annual precipitation averages somewhat more 


than 12 inches, about half of which falls in the 4 


months from February to May. The rainfall of the 


summer and early fall is commonly in the form of 


severe thunderstorms or cloudbursts. Snowstorms 


may be expected from October to May. 


The following tables present climatic data for 

Ibapah, in the southwest corner of the quadrangle, 

furnished by the United States Weather Bureau. 

The conditions at the town of Gold Hill are similar, 

except that the extremes of temperature are somewhat 

less pronounced. 

Monthly and annual mean temperature at Ibapah, Utah (0 F.) 

Year Jan. Mar. Apr. June 

1903-18__ 24. 7 
 27.9 35. 6 
 44. 7 
 48.5 56. 7 


1919_ 27. 7 
 30.6 36.1 45. 8 
 56. 2 
 61. 2
 1920______ 24. 2 
 31. 8 
 33.6 38. 6 
 50.8 58.4 

1921 
 •• __ 1 
 29.2 33.2 40.5 40. 3 
 54.1 61. 2 


1922_ J 15.6 25.1 32.4 38. 6 
 50. 8 
 63. 8


1923_ 31. 0 16.4 31. 8 
 40. 4 
 51. 2 
 54. 8
 1924___ 19.7 36. 8 
 31. 6 
 44. 6
 50.4 62. 4
 1925 ___ 25. 4 
 36.3 40. 2 
 45.8 56.3 60. 6
 1926___ 23.8 34. 4 
 39. 0 49. 7
 54. 2 
 64. 6
 1927_____ 27.4 32.8 38.4 43.3 51. 5 
 62.0 

1928_ 24.0 30. 0 42.5 44.2 56. 9 
 60. 4
 1929________ 22.9 25. 9 
 38. 6 
 46. 0 52. 6 
 57.7 

Year July Au)!. Sept. 

1903-18__ 65. 8 
 65. 9 
 56.6 44. 7 
 44.2 1919____ 70.1 69.0 59. 7 
 37.7 45. 6
 1920______ 68. 2 
 65.6 58.1 43. 5 
 44. 2 


1921 -----­ 68.6 66. 3 
 54. 1 
 51. 0 47.4; 1922_ 68. 8 
 67. 4 
 60. 8 
 47. 6 
 44. 2 


1923_ 70.7 64. 9 
 59.3 43. 4 
 43. 5
 1924- ___ 68. 5 
 65. 3 
 56. 8 
 46. 0 44. 8
 1925_______ 71.2 (a) 56. 0 46.4 1926_______ 68.6 68. 0 54. 8 
 47.2 47. 5
 1921- ______ 70. 6 
 65.3 56. 0 48. 6 
 46.8 1928____ 67. 2
 - 69.6 59. 8 
 49. 5 
 46. 7
 1929____ 71. 7 
 70. 5 
 60.8 53. 0 47.7 

• No record. 

Monthly and annual precipitation at Ibapah, Utah (inches) 

Year Jan. Feb. Apr. May Juue 

1903-18___ 1. 04 L 33 
 1. 31
 O. 89 1. 98 0.97 1919_______ .00 1. 91 
 1. 46
 1. 07 .26 .00 

1920_ .82 
 .58 
 2. 66 
 2. 74 3. 20 .40 


192L -----­ .50 
 .40 
 .91 
 3.51 3.51 .24


1922_ 1. 16 
 1. 46 
 1. 01 2. 32 .76 .23
 1923 __________ 1. 03 .50 
 .67 
 1. 86 2.12 .74
 1924__ .09 .12
 1.35 1. 68 .29 Trace 1925_____ .28 
 .48 
 .95 
 .96 1. 08 2.63 1926____ .89 
 1. 24 
 .86
 .68 .83 .70
 1927_____ .56 
 1. 01 1. 61
 2.19 1. 09 1. 02 

1928_ ­ .65 
 1. 52 
 3.14 1.10 1.40 2.84 

1929_ -----­ .59 
 .77 
 1.10 2.31 .70 .95 

- -

- -----

---

-----

------ ------

GOLD HILL MINING DISTRICT, UTAH 3 

Monthly and annual precipation at Ibapah, Utah (inchea)­

Continued. 

Year July Aug. Sept. Oct. Nov. Dec. Annual 

1­

1903-18___ 12.27 

1919_ 

0.91 O. 86 O. 69 0.96 O. 67 0.66 

1. 21 1. 04 9.11 

1920_ - .14 .66 1. 02 .34

2.04 .74 17.87 

192L. - 1. 79 1.37 .88 .65

.25 14 98 

1922_ 

.78 2.69 .37 .32 1. 50 

.93 3. 00 .00 .67 .99 1.71 14. 24

1923___ .84 .83 1. 83 2.21 .50 1. 40 14.53 

1924__ .34 .69 .52 1. 32 .80 1. 24 8.44 1925_______ 1.45 .72 .94 .66 .67 .11 10.93 1926 ______ 2. 03 1. 33 .14 .33 1. 55 1. 45 12.03 1927 ______ .40 12. 48 

1928_ 

.36 .67 1. 14 1. 54 .89 

.66 .25 .00 1. 54 .60 1. 38 15.08 

1929_ - .10 2.15 1. 45 .00 .00 .27 10.39

Miscellaneous climatic data for Ibapah, Utah,1925-29 

Lowest temperature 

Year 

OF. 

Highest temperature 

Date of. Date

1925_ --- -­ 104 July 14 -2 Jan. 7

1926____ -16 Dec. 27 

1927 __ 99 June 26 

98 July 19 -20 Jan. 22

1928 ______ -19 Dec. 22 

1929..... --. - ­

100 July 27 

102 July 25 -20 Jan. 24

I~ Number of days 

Snowfall Year IWitb 0.01 (inches) Partly . inch of Clear Cloud} precipitation cloudy 

1925__ -- ____ . ­ 24. 4 178 138 49 74

1926 _, _______ . 51. 2 185 128 50 59

1927 _,_ . ------­

- 54.2 160 155 50 59 

1928. __ ­ 70.0 181 147 38 60 

1929___ 35. 5 192 128 45 46

Th.e higher portions of the Deep Creek Range and 

small areas near the summits of Ochre Mountain and 

Dutch Mountain support a fairly heavy growth of 

yellow pine, small quantities of which are cut for local 

use. The lower slopes of these higher tracts have a 

sparse covering of juniper and pi:fl.on trees, few of 

which reach a height of 15 feet. On the lower hills 

and on the gravel slopes surrounding them these 

stunted trees give way to the group of shrubs characterized by the sagebrush, and the irregular and 

scattered distribution of these plants provides the 

"spotty" appearance that is so characteristic of the 

lower altitudes of this portion of the Great Basin. 

The floor of Deep Creek V alley is cultivated in 

several places where water for irrigation is available, 

and the green fields provide a striking contrast to 

the more somber coloring of the surrounding slopes. 

The floor of the Great Salt Lake Desert in the northeast corner of the quadrangle, on the other hand, is 

almost completely barren of vegetation, 

FIELD WORK AND ACKNOWLEDGMENTS 

PREVIOUS WORK 

The first published record of exploration within the 

quadrangle is found in the report of Lt. E. G. Beckwith.I His party, after crossing the Great Salt Lake 

Desert, camped at what is now known as Redding 

Springs, just beyond the southeast corner of the area. 

His report suggests that there had been no previous 

travel through this part of the country, for the presence 

of Overland Canyon, which was later in general use, 

was unknown either to him or to his Indian guides. 

He discovered the pass through the canyon, however 

by following the crest line of the range northward 

and noted the presence of "metamorphic [quartzite?] 

shale, and limestone." 

By 1866 much of the travel between San Francisco 

and Salt Lake City had become concentrated on the 

overland stage route that passed through Redding 

Springs, Overland Canyon (then known as Uiyabi 

Pass), and Deep Creek, where a settlement had been 

established. 2 Ruins of the old corrals may still be 

seen at Ibapah and south of Clifton. The first transcontinental telegraph line also followed this route. 

The geologists of the Wheeler and Fortieth Parallel 

Surveys followed the overland route, and reports of 

both contain notes on the general geology.3 Neither 

recognized the intrusive character of the granitic rocks, 

considering them the Archean basement upon which 

the sediments were deposited. 

Gilbert visited the area again in the course of his 

field work on Lake Bonneville and recorded postBonneville disturbances on the east side of the range.4 

In 1892 Blake 5 noted the intrusive character of the 

granitic rock and the attendant contact metamorphism. 

In the same year Kemp 6 described several rocks from 

the region, one of them an andalusite hornfels from a 

point near the Cane Springs mine. 

Kemp visited the region himself in 1908 and later 

published his observations in a joint paper with 

Billingsley,7 who had studied the ore deposits in 1913. 

In 1912 Butler 8 made a rapid reconnaissance through 

the district. 

1 Beckwith, E. G., U.S. Pacific R.R. Expl. Rept.: 33d Coni., 1st sese., H.Ex.Doc. 

129, Vol. 18, pt. 2, P.' 24. 1855. 

, Browne, J. R., Mineral resources of the StatesliIld Territories west of the Rocky 

Mountains for 1866, p. 267, 1867. 

'GUbert, G. K., U.S. Geog. and Geol. Surveys W. l00th Mer. Rapt., vol. 3, 

pp.3O, 123, 182, 1875. Hague, Arnold, and Emmons, S. F., U.S. Geol. Expl. 40th 

Par. Rept., vol. 2, pp. 472-476. 1877. 

• Gilbert. G. K., Lake Bonneville: U.S. Geol. Survey Mon. 1. p. 353, 1890. 

, Blake, W. P., Age of the limestone strata of Deep Creek, Utah, and the occurrence of gold in the crystalline portions of, the formation: Am. Geologist, vol. 9, 

pp.47-48, 181)2; Eng. and Min. Jour., vol. 63, p. 2j3, 1892 . 

• Kemp. J. F., Notes on several rocks collectel by E. E. Olcott, E. M., near Gold 

Hill, Tooele County, Utah: New York Acad. Sci. Trans., vol. 11. PP. 127-128. 181)2. 

'Kemp, J. F., and Billingsley, Paul, Notes on Gold Hill and vicinity, Tooele 

County, western Utah: ECOD. Geology, vol. 13. pp. 247-274. 1918. 

B Butler, B. S., and others, The ore deposits of Utah: U.S. Geo!. Survey Prof. 

Paper 111, pp. ~5. 192(). 
4 GOLD HILL MINING DISTRICT, UTAH 

Since the completion of the railroad in 1917 several 

short articles have appeared, dealing mainly with the 

mines and prospects. 

PRESENT WORK 

The reconnaissance work of B. S. Butler in 1912 

showed that it was desirable to make a more detailed 

study of the Olifton district, but it was not until 1924 

that conditions permitted the initiation of the work by 

the Geological Survey. Topographic mapping was 

started in that year by a party under R. T. Evans and 

was completed the following year by W. J. Lloyd and 

E. S. Rickard. The general excellence of the topographic map produced greatly facilitated the geologic 

field work, which was started by the writer July 12, 

1925. Work continued that season through September' 

28 but was several times interrupted by another 

assignment. The field work was resumed April 26, 

1926, and continued until November 6. During most 

of this season Frank A. Melton also participated in 

the field work. Dr. Melton is responsible for the 

greater part of the mapping of the southern and 

western flanks of Ochre Mountain and also collaborated 

in the mapping of the southern third of the quadrangle. 

The geologic mapping was completed during the 

season of 1927, which extended from April 25 to 

August 7. During this period the writer was ably 

assisted by William D. Mark, who mapped in detail 

the numerous dikes southeast of Dutch Mountain. 

The w~iter is glad to acknowledge the whole-hea.rted 

cooperation and hospitality of the people of the district, all of whom assisted the work freely. Particular 

thanks are due to Messrs. Rowley, Greenwood, and 

Tiffany, of the Western Utah mine; Mr. Lefller Palmer, 

of the Rube mine; Mr. James Busby, of the U.S. 

mine; and Messrs. Gerster and Ollie Young, whose 

knowledge of the earlier history of the district was very 

helpful. Mr. V. O. Heikes, formerly of the Geological 

Survey and later of the Bureau of Mines, assisted the 

work in every way and provided considerable material 

that would not otherwise have heen available. 

During the course of the field work Edwin Kirk 

and G. H. Girtv made short visits to the quadrangle 

and were of theVutmost assistanee in the determination 

of the stratigraphy of the pre-Oarboniferous formations. The writer was also greatly benefited hy the 

visits of G. F. Loughlin, made each season, during 

Schaller, O. S. Ross, M. N. Short, and E. P. Henderson, 

and the chemical analyses of the volcanic rocks are 

the work of J. G. Fairchild. The photomicrographs 

are in large part the result of Mr. Short's unusual skill 

with the microscope and camera. 

GEOLOGIC FORMATIONS 

In the following sections are described in their proper 

chronologic order the 28 geologic formations that are 

distinguished on the geologic maps (pIs. 1 and 2). 

Of these formations 24 are composed of sedimentary 

rocks and 4 of igneous rocks. 

Of the sedimentary formations 20 are of Paleozoic 

age~8 in the Oambrian, 2 in the Ordovician, 1 in the 

Silurian, 3 in the Devonian, and 6 in the Oarboniferous. 

Only 1 formation is assigned to the Mesozoic, a limestone of Lower Triassic age. The remaining 7 formations are thought to belong in the Tertiary. One 

of these is considered to be probahly Eocene; an intrusive stock of quartz monzonite and two kinds of 

allied dike rocks are placed in the late Eocene or early 

Oligocene; a series of gravel deposits are questionably 

assigned to the Pliocene; and a group of volcanic 

rocks are tentatively put in the late Pliocene. The 

youngest formation in the quadrangle, composed of 

gravel and lake beds, is of Pliocene (?) to Recent age. 

CAMBRIAN SYSTEM 

PROSPECT MOUNTAL.'<" QUARTZITE (LOWER CAMBRIAN) 

Distribution.-The Prospect Mountain quartzite is 

the oldest formation exposed within the quadrangle. 

The two largest outcrops are bands of varying width 

on the east sides of Dutch Mountain and the Deep 

Oreek Mountains. 

The exposure in the Deep Oreek Mountains is nearly 

3 miles long and narrows from 4,000 feet in width at 

the 40th parallel to less than 500 feet at Bagley Gulch, 

where the formation ends against a transverse fault. 

The quartzite forms the east base of the mountains, 

its resistant beds rising abruptly from the gravel slopes 

to the east. 

The outcrop on the east side of Dutch Mountain is 

also about 3 miles long and is bounded on the east by 

recent gravel. It varies considerably in width, owing 

to encroachment of gravel on the east and to faulting 

on the west. The width ranges from a few hundred 

feet at the mouth of Tribune Gulch to more than 1~~ 

which his helpful criticisms and advice greatly facili­ . miles along the ridge 2 miles to the north. A transtated the geologic mapping. verse fault just south of the Garrison Monster mine 

The preparation of the present report has been in­ marks the nort.hern limit of the formation. 

fluenced throughout by the discussions and criticisms In addition to these principal exposures there are 

of the writer's colleagues on the Geological Survey, several smaller outcrops north and east of the Gold 

especially James Gilluly, and he wishes to express his Hill mine. These are either completely or partly surappreciation, particularly to H. G. Ferguson, D. F. rounded by gravel and are in all probahility continuHewett, M. X. Short, and G. F. Loughlin, who have ous beneath the gravel. The largest of these areas of 

read and criticized the final manuscript. Many of the quartzite forms the prominent summit at an altitude 

mineralogic determinl1tions were made by W. T. of 5,556 feet east of the Rube mine. 
GliJOLOGIC FORMATIONS 5 

Another small outcrop of the Prospect Mountain 

quartzite surrounded by gravel is found near the edge 

of the Great Salt Lake Desert, 1 mile east of benchmark 4552 on the Deep Creek Railroad. 

Lithology.-The Prospect Mountain quartzite is composed chiefly of light-gray to dark-brown quartzite, 

but near the base of the exposed section on Dutch 

Mountain there are one or more zones containing a 

large proportion of shaly material. These zones are 

distinguished on the geologic map as shale members. 

'fhe apparent homogeneity of the quartzite portion 

of the formation is due largely to the general presence 

of a brownish stain of iron oxides on the weathered 

surfaces, but close examination shows several distinct 

varieties of rock. Of these the most widely distributed 

is a fine to medium grained quartzite which is pale 

pinkish on fresh fracture. The grains are partly 

rounded and closely packed, the quartz cement between 

grains forming a very small portion of the total rock. 

A second variety has similar grain but is rather dark 

purplish on fresh fracture, owing to the presence of 

iron oxides in the cementing material. This variety 

is usually found interlaminated with the lightercolored variety, and the difference in color reveals 

cross lamination throughout. The laminae meet at 

low angles (generally 10° or less) and may be truncated by others both above and below. Where the 

rock consists of only one variety this cross lamination 

is not visible, even on weathered surfaces. At no 

place was the cross lamination found to depend on 

varying size of grain. On the contrary, it seemed to 

be eonfined to the finer-grained quartzites just 

described. 

In addition to the fine-grained quartzites, many 

beds are composed largely of quartz grains from 5 to 

10 millimeters in diameter. The larger grains are less 

rounded than the smaller ones and locally consist of 

altered feldspars instead of the usual quartz. The 

larger grains lie in a matrix of smaller quartz grains, 

and by an increase in the amount of these smaller 

grains the rock grades into typical fine-grained quartzite: In general these coarser-grained quartzites are 

light-colored on fresh fracture. Within both coarsegrained and fine-grained quartzites there are beds of 

conglomerate as much as 2 feet thick. The pebbles in 

these beds are predominantly of white vein quartz, 

with a minor proportion of rose quartz and a very few 

of red jasper. The maximum size of pebble observed 

was about 75 millimeters and the average size about 

25 millimeters. Such conglomerate beds are lenticular 

and cannot be traced for any great distance along the 

strike. They were found extremely useful, however, 

in proving the identity of the rocks in the scattered 

and metamorphosed exposures east of the Rube mine, 

where the Prospect Mountain quartzite has been 

faulted against the Oquirrh formation, which there 

consists largely of fine-grained sandstone without 

conglomerate layers. 

In many places the bedding is marked by thin shale 

zones, in others by the change from a dominantly 

colored bed to one almost colorless, and in still others 

by an abrupt change in grain size. Wherever areas of 

such bedding planes have been exposed by erosion any 

sedimentary structural features, such as ripple marks, 

that may have been present have been destroyed by 

later movements parallel to the bedding surface. 

The upper 75 to 100 feet of the quartzite differs 

from the beds beneath in several respects. The most 

noticeable difference is in the thickness of the individual beds, which ranges from 10 to 30 feet, in contrast 

to 1 to 5 feet in the remainder of the formation. 'fhe 

color 011 fresh fracture is a medium gray, but weathered 

surfaces are of a uniform dark brownish red, which 

results from the leaching and subsequent deposition of 

iron from nu~erolls pyrite cubes scattered throughout 

the rock. The size of grain (1 to 2 millimeters) is 

somewhat larger than in many of the lower beds, and 

cross lamination is apparently absent. 

A conglomerate occurs just beneath this upper part 

of the quartzite. It is best exposed south of Dry 

Canyon but may also be found for a mile or so to the 

north, usually as float. Itis a dark rock that commonly 

forms a bench, with the result that its relations in most 

croppings are obscure. Its chief feature of interest is 

that its pebbles represent several different kinds of 

rock and thus differ markedly from those of the quartzpebble conglomerates described above. The pebbles 

are angular to subangular and are as much as 6 inches 

in maximum diameter. Manv are tabulnr or slaty. 

They include quartzite, schists, especially a quart~­

biotite schist, slate, and various altered igneous rocks, 

one pebble of a granitic rock being noted. With these 

are smaller quartz grains, such as are found in the 

quartzites below. The matrix is in most places a 

slate, in which abundant specular hematite has been 

developed, but locally it is a fine-grained quartzite. 

Along the strike, to the north of Dry Canyon, the bed 

contains but few pebbles and is not unlike other shale 

beds in the formation, except for its greater thickness. 

Similar beds of shale are present at several other 

horizons in the formation. These are generally only a 

fraction of an inch thick but locally are as much as a 

foot. In the thicker beds slaty cleavage has been 

developed. 

In all expo.'lUres the Prospect Mountain quartzite· is 

cut by numerous joints. As a rule, these are parallel 

in strike find dip to nearby major or minor faults. 

On Dutch Mountain the formation is so thoroughly 

jointed that it has weathered into angular blocks 

which conceal bedrook exposures over wide areas. 

Along the fault planes the quartzite, in addition to 

being brecciated, has been bleached to a dull white 

color. Discontinuous thin veinlets of white quartz are 

found everywhere. No general course for the veinlets 

was ascertained, other than that many follow the 

bedding planes. 
6 GOLD HILL MINING DISTRICT, UTAH 

Shale member8.-On the lower slopes of the east side 

of Dutch Mountain, there are several exposures of 

slaty shales and rather thin-bedded dark quartzites. 

These have been distinguished on the geologic maps 

(pIs. 1 and 2) as shale members. Exposures on Basin 

Creek, in the Deep Creek Mountains south of the 

quadrangle, show that they are conformably interbedded with the normal light-colored Prospect Mountain quartzites at the bottom of the section exposed 

there. These beds are similar in lithology and position 

to the poorly exposed beds on Dutch Mountain. The 

shales are generally a dark grayish blue or greenish 

blue, though locally shades of khaki color are observed. 

Many beds are distinctly sandy, and in almost all of 

them a pronounced slaty cleavage, essentially parallel 

to the bedding, has been developed. The quartzite 

beds are mostly 6 inches or less in thicbess. They 

are much darker than the quartzites that make up the 

greater part of the formation, owing to a larger content 

of impurities. 

Thickne88.-No complete section of the Prospect 

Mountain quartzite was observed. In the southern 

part of the quadrangle a maximum thickness of about 

800 feet is exposed, and on Dutch Mountain the beds 

probably exceed 3,000 feet, although the exposures 

there are much too poor for measurement. A rapid 

and very rough measurement of the exposed portion of 

the formation was made on Basin Creek, about 7 

miles south of the 40th parallel. This amounted to 

4,750 feet and may be summarized as follows: 

Section of Prospect Mountain qu.artzite on Basin Creek 

Cabin shale. Feet 

Massive, dominantly light-colored quartzite_ _ __ _ _ _ _ _ 2, 500 

Slate and quartzite (shale member) _ _ _ _ _ _ _ _ _ _ _ _ _ _ 300 

Light-colored quartzite_ _ _ _ _ __ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ 500 

Slate and quartzite (shale member)_ ________________ 600 

Light-colored quartzite_ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ ___ 200 

Shale and quartzite (shale member) _ __ __ ___ __ ___ _____ 100 

Light-colored quartzite________ ______ _____________ 500 

Shale_______ .. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 50 

Base not exposed. 

4. 750 

Age and correlation.-No fossils have been found in 

the Prospect Mountain quartzite, but as there is no 

apparent break of importance between it and the overlying Cabin shale, which contains Lower Cambrian 

fossils, the formation is considered to be of Lower 

Cambrian age. 

A quartzite series of varying thickness, occurring 

beneath the lowest fossiliferous Cambrian, which 

usually is 8 shale, is widespread over western Utah 

and eastern and southern Nevada. In the Nevada 

localities that have been described the formation is 

over 1,000 feet in thickness and is overlain by Lower 

Cambrian sediments. The name Prospect Mountain 9 

• Hague, Arnold, Abstract of tbe report on tbe geology of tbe E\ll'eka district, 

Nevada: U.S. Gool. Survey Tblrd Ann. Rept., p. 254, 1883. 

quartzite has been generally applied to the formation. 

For Utah Butler 10 suggested the name Tintic quartzite, from the Tintic Mountains, for this formation. 

However, as the overlying shale has been determined 

to be Middle Cambrian at some localities in Utah 

(as at Tintic 11 and Blacksmith Fork 12), thus suggesting 

that the top of the quartzite may here be Middle 

Cambrian, and to be Lower Cambrian at others 

(Oquirrh Range 13), and also as the Nevada name has 

priority, the formation is here called Prospect Mouns 

tain quartzite rather than Tintic quartzite. 

Several investigators in the Wasatch Range in 

recent years have shown the presence of an unconformity in the thick nonfossiliferous and predominantly 

siliceous sediments below the fossiliferous Cambrian 

and have considered it to mark the boundary between 

the Cambrian and the Algonkian. 14 This unconformity 

is marked by a thin conglomerate, containing pebbles 

of the underlying rocks. Because of this discovery it 

was at first thought that the conglomerate near the 

top of the formation in the Gold Hill region might 

mark the Cambrian-Algonkian contact, as it contains 

boulders of different kinds of rock, and in some exposures its lower contact is discordant. But further 

field work and comparisons with the published descriptions of the unconformity in the Wasatch Range have 

led to the conclusion that the conglomerate in the 

Gold Hill region is of only local significance. This 

conclusion is based chiefly on its slight extent, its 

gradation northward into shale similar in appearance 

to other shale beds both above and below, and the 

dissimilarity of the quartzites below it to any of the 

known Algonkian beds in the Wasatch Range. 

CABIN SHALE (LOWER CAMBRIAN) 

Di8tribution.-The Cabin shale, named from Cabin 

Gulch, between North Pass and Sheep Canyons, crops 

out as a narrow band above the Prospect Mountain 

quartzite on the east side of both the Deep Creek 

Mountains and Dutch Mountain. On the southeast 

flank of Dutch Mountain the shale is concealed by 

faulting, and the Prospect Mountain quartzite is in 

contact with higher beds. The formation is much 

less resistant to erosion than the quartzites above and 

below and in most localities forms a narrow brushcovered bench. 

Lithology.-The formation is dominantly shaly, the 

typical rock being a dark-green 00 khaki-colored shale, 

10 Butler, B. S., Ore deposits 01 Utah: U.S. GeoL Survey Prot. Paper Ill, p. 78, 

1920. 

U Lougblin, G. F., Geology and ore deposits of the Tlntic mining district, Utab: 

U.S. GeoL Survey Prof. Paper 101, p. 25, 1919. 

II Walcott, C. D., Cambrian sections of the Cordilleran area: Smltbsonian Misc. 

COiL, vol. 53, no. 5, p. 111, 1008, 

11 Emmons, S. F., in Spurr, J. E., Economic geology of tbe Mercur mining dis· 

trict, Utab: U.S. Geol. Survey Eigbteenth ADD. Rept., pt. 2, p. 362, 1895. 

11 Blackwelder, Eliot, New light on tbe geology 01 tbe Wasatcb Mountains, Utab: 

Geol. Soc. America BniL, vol. 20, pp. 52(}-523, 1910. Hintze, F. F., A contribution 

to tbe geology 01 tbe Wasatch Mountains, Utab: New York Acad. Sci. Annals, 

vol. 23, p. 103, 1913. Calkins, F. C., Ore deposits or Utah: U.S. Geol. Survey Prof. 

Pa.per 111, p. 235, 1p20. 
GEOLOGIC 7 

with little sandy material and almost no calcium carbonate. Weathered surfaces are lighter in color and 

in most places are shades of brownish red. Slaty cleavage is developed in much of the formation, as a rule 

nearly parallel to the bedding, though in several places 

it cuts the bedding at a small angle. The slaty cleavages are generally marked by the development of 

flakes of white or golden-colored mica. In many beds, 

especially those near the base of the formation, cubes 

of limonite pseudomorphous after pyrite are present. 

There are several variants from the typical rock 

just described. One of these is a light-gray finely laminated shale, generally 2 feet or less thick, found at the 

base of the formation, both in the Deep Creek Mountains and on Dutch Mountain. Near the middle of 

the section the shale locally contains small amounts of 

calcite, as shown by a weak effervescence with dilute 

hydrochloric acid. This limy variety is of a lighter 

color than the rest of the rock. On fresh fractures it 

is a light greenish gray, and on weathered surfaces 

brownish or reddish yellow. Both near the base and 

near the top of the section thin lenticular laminae of 

sandstone are found. These are 1 millimeter or so 

thick and are of lighter shades than the thicker interbedded shale. 

Just beneath the top of the formation there is a persistent and, for this formation, unique concretionary 

bed. The numerous concretions are about the size 

of a silver dollar and lie parallel to the bedding planes. 

They differ from the remainder of the rock in having 

a slightly darker color, a somewhat finer grain of the 

mica, and a larger proportion of sand. 

The lower contact of the shale is notably sharp. 

The light-gray shale mentioned above rests upon thickbedded Prospect Mountain quartzite with no observable transition. There is, however, no indication of 

anything other than a purely lithologic break. The 

upper contact is not so well defined. The line has been 

drawn at the top of a I5-foot zone of interbedded 

sandy shale and shaly quartzite. Many of the quartzite beds are flecked with iron oxides. Above the 15­

foot interval are the basal thicker-bedded Busby 

quartzites. 

Thic"kness.-Two measurements of the thickness of 

the Cabin shale gave 493 and 530 feet. The first was 

made on the ridge south of Sheep Canyon and the 

second on the north side of Cabin Gulch. A third 

section, measured on the south side of Dry Canyon, was 

only 114 feet thick; and a fourth, half-way between the 

Spotted Fawn mine and the Garrison Monster mine, 

381 feet. The first two figures are thought to approximate the true thickness. The diminution in thickness indicated by the other measurements was probably effected by local overriding within the shale 

along strike faults, but exposures are generally too 

poor to permit exact proof. Such variations in thickness are numerous on Dutch Mountain, and some are 

also found in the Deep Creek Mountains. 

FORMATIONS 

Age and correlation.-A single fragmentary trilobite 

was found by Edwin Kirk in the Cabin shale at a horizon somewhat above the middle of the formation. It 

was submitted for identification to Dr. C. E. Resser, 

of the Smithsonian Institution, who reported as follows: "The thoracic segment from Sheep Canyon, 

because of the sharp angle on its anterior side, seems 

pretty definitely to belong to a mesonacid, which would 

make it Lower Cambrian in the present usage of that 

term in the West." 

It is rather difficult to determine the exact correlation of the Cabin shale in the published sections from 

areas in Utah and Nevada. The sequence quartzite, 

shale, and limestone is common to most of these sections, but fossil collections from the shale zones in 

areas in Utah and Nevada indicate a lack of contemporaneity in deposition. For this reason, the loeal name 

Cabin shale has been applied to the shale found at Gold 

Hill, rather than Pioche shale or Ophir shale, which 

have been widely used in Nevada and Utah, respectively. 

It is probable that the formation closest in age to 

the Cabin shale is the lowest shale belt in the House 

Range, which was called Pioche by Walcott. 1. The 

Pioche shale, in its type locality,16 differs from the 

Cabin shale in being over twice as thick and in containing several limestone beds. It probably includes 

in the lower part beds older than those present in the 

shale at Gold HilL 

The shale zones in the Tintic,t7 Ophir,ts and Cottonwood-American Fork 19 areas, however, are, on the 

whole, younger. These shales, known generally as the 

Ophir shale, contain Middle Cambrian fossils through 

the greater part of their extent, but in the Ophir and 

Cottonwood districts Lower Cambrian fossils have been 

reported from the basal portions. The Cabin shale is 

perhaps equivalent in age to the lower portion of the 

shale and the upper beds of the underlying quartzite 

at these localities. 

BUSBY QUARTZITE (MIDDLE CAMBRIAN) 

Distribution.-In the Deep Creek Mountains the 

Busby quartzite is terminated on the south side of 

North Pass Canyon by the same transverse fault that 

cuts off the outcrops of the Cabin shale and Prospect 

Mountain quartzite. The quartzitic beds of the Busby 

are fairly resistant to erosion and form a series of low 

cliffs above the weak shale beds beneath. The formation is exposed also on Dutch Mountain in a band 

of extremely irregular width from a point half a mile 

south of the Spotted Fawn mine to the transverse 

U Walcott, C. D., Cambrian sections of tbe Cordilleran aroo: Smitboonian Misc. 

Call., vol. 53, no. 5, p. 184, 1908. 

.. Westgate, L. G., Geology and ore deposits of tbe Piocbe district, Nev.: U.S. 

Geol. Survey Prof. Paper 171, pp. S-10, 1932. 

17 Loughlin, G. F., Geology and ore deposits ot the Tintic mining district, Utah: 

U.S. Geol. Survey Pro!. Paper 107, p. 29, 1919. 

19 GiUuly, James, Geology and ore depOSits of the Stockton and Fairfield quadran· 

gliS, Utah: U.S. Geol. Survey Prot. Paper 173, pp. 9-12, 1932. 

" Calkins, F. C., The ore deposits ot Utah: U.S. G001. Survey Prof. Paper 111, 

P. 237. 1920. 
GOLD HILL MINING DISTRICT. UTAH 

fault south of the Garrison Monster mine. Another 

small outcrop is found in the foothills west of Garrison 

siding on the Deep Creek Railroad. The formation 

is poorly exposed on Dutch Mountain, because of the 

numerous faults which cut it and cause either duplication or elimination of individual beds. The name is 

taken from Busby Canyon, on the east slope of Dutch 

Mountain, in which the formation is exposed. 

Lithology.-The basal portion of the Busby quartzite, 

50 to 75 feet thick, is a fairly coarse grained rock, graybrown on fresh fracture and weathering to shades of 

reddish brown. Many of the grains are more than 1 

millimeter in diameter and a few are as much as 5 millimeters. Most of the grains are of quartz, and the 

remainder are of rock fragments, so that this rock 

locally resembles a graywacke. Shale partings are 

present and in places show mud cracks, which are 

filled by the coarser sands that make up the main 

portion of the rock. Iron oxide flecks are abundant. 

A rather distinctive variety is found near the base 

of the formation in the Dutch Mountain exposures. 

This is a white quartzite containing irregular darkbrown patches. Thin sections of it show that the 

brown portions of the rock differ from the white portions only in the presence of abundant interstitial iron 

oxide. The quartz in this as well as in other quartzitic 

parts of the formation is crowded with microscopic 

fluid inclusions, in many of which gas bubbles are 

present. 

Above the basal, coarse-grained quartzite there is 

little uniformity or continuity in the strata. Finegrained sandy and shaly material are the principal 

components and are present in varying proportions in 

the individual beds. The most abundant varieties 

are thin-bedded pink to purplish fine-grained quartzites and thin-bedded gray quartzitic sandstones which 

are in many places micaceous. Green sandy shales 

are less abundant than the quartzite and sandstone 

except near the top of the formation, where they 

predominate. 

The top of the formation has been placed at the base 

of the lowest limestone bed. The contact is not sharp, 

as there are a few thin quartzite beds above the boundary as thus drawn. It is also rather certain that the 

lowest limestone is not a continuous bed. But the zone 

including the lowest limestone and highest quartzite, 

which probably does not exceed 25 feet in thickness, 

makes a distinct lithologic break from beds of distinctly sandy and shaly character to beds characteristically calcareous. 

Thickness.-Sections of the Busby quartzite measured on the south and north sides of Dry Canyon and 

the north side of Sheep Canyon gave thicknesses of 

519, 433, and 452 feet, respectively. A fourth measurement about halfway between the Spotted Fawn and 

Garrison Monster mines showed 314 feet. The first 

figure possibly includes some duplication caused by 

undetected normal faulting; and the fourth is probably 

much too small for the same reason. The second and 

third figures are believed to be fairly close to the true 

thickness. 

Age and correlation.-In addition to numerous annelid (?) trails a single fragmentary trilobite was found 

in the Busby quartzite, but unfortunately it was lost 

before being identified. The overlying Abercrombie 

formation contains abundant remains of a Middle 

Cambrian fauna, whereas the shale beneath the Busby 

is of Lower Cambrian age. Because of the presence 

of coarser material at the base of the formation, the 

lack of a sharp contact between the Busby and the 

Abercrombie, and the evidence of shallow-water conditions indicated by mud cracks, the Busby quartzite 

is thought to be best considered the initial deposit of 

the Middle Cambrian rather than the final deposit of 

the Lower Cambrian. No evidence of an angular 

unconformity at the base was seen, however, and it is 

indeed negatived by the continuity of the concretionary 

bed of the Cabin shale, which lies immediately beneath 

the base of the quartzite, and the presence of 15 feet 

of gradational beds. . 

In stratigraphic position the Busby is probably equivalent to the Langston (?) formation in the House 

Range 20, which lies above a sandy shale and is furthermore described as being almost a sandstone at the 

base. The correlation of the formation with other 

Utah sections is not certain except that it may represent that part of the Ophir shale, as exposed in Cottonwood Canyon 21 and the Oquirrh Mountains,22 lying 

above the Lower Cambrian portion. 

ABERCROMBIE FORMATION (MIDDLE CAMBRIAN) 

Distribution.-The Abercrombie formation, named 

from Abercrombie Peak, on the ridge south of Dry 

Canyon, is completely exposed only in the southern 

third of the quadrangle, where it crops out as a wide 

band along the eastern part of the Deep Creek Mountains. This band is terminated on the north side of 

North Pass Canyon, in part by the overriding of 

younger formations adjacent to a transverse fault, but 

chiefly by burial beneath gravel. Incomplete and badly faulted sections are found on the east and northeast 

sides of Dutch Mountain from a point south of the 

Spotted Fawn mine northward nearly to the northern 

limit of the quadrangle. 

Lithology.-The Abercrombie formation is composed 

dominantly of thin-bedded argillaceous limestone, 

interbedded with which are a few beds of more massive 

limestone and considerable amounts of shale. Except 

for the more massive limestone beds the formation is 

in general poorly exposed. The shale in particular 

20 Walcott, C. D., Cambrian sections of the Cordilleran area: Smithsonian Misc. 

Coli., vol. 53, no. 5, p. 183. 1908. 

21 Calkins. F. C., Ore deposits of Utah: U.S. Gool. Survey Prof. Paper Ill, pp. 

235-236, 1919. .. Gilluly, James, Geology and ore deposits of the Stockton and Fairfield quadrangles, Utah: U.S. Gool. Survey Prof. Paper 173, pp. 11-12, 1932. 
U.S. GEOLOGICAL SUHVEY PROFESSIONAL PAPER 177 PLATE 4 

A. BONNEVILLE BEACH AND SPIT, EAST OF DUTCH MOUNTAIN. 

H. DUTCH MOUNTAIN l"RO:vI THE SOUTHEAST. 

C. CLIFTON FLAT FROM THE SOUTHWEST. 
U.S. GEOLOGICAL SURVEY I'ROFE>;fHONAL PAPER 177 PLATE 5 

B 

A 

c 

ROCKS OF GOLD llILL QUADRA:>GLE. 

A. Mottled Young Peak dolomite; By laminated TripRc limestone; Ct pisolilic dolomite from the Hicks formation; D, "mll['h1e cuke 1! dolOInite near the base of the 
 Laketown dolomile; E, laminated Simonson dolomite; F, cherL-pt'.hble conglomerate wilh oo1ilic mat.l'ix from Oquirrh formalion. 

GEOLOGIc FORMATIONS 9 

crops out in but few places, usually forming a bench 

between steeper slopes underlain by more resistant 

limestone. 

The rock most characteristic of the series is a bluegray dense limestone whose thin bedding is caused by 

thin partings of shale, most of which are yellow or 

buff, though locally pink or light-gray colors are found. 

The limestone portions are from a quarter to half an 

inch thick and leave a large residue of clay when dissolved in hydrochloric acid. The shale partings contain minor amounts of calcite and quartz but are dominantly made up of a clay mineral of low birefringence. 

The thickness of the shale partings averages about 1 

millimeter but is extremely variable. Along many of 

the bedding planes the shaly material is present only 

locally, resulting in a mottling by splotches of yellow 

or reddish shale. Less commonly splotches that are 

not parallel to the bedding may be found within the 

limestone. This variety is best developed near the 

top of the section in North Pass Canyon, where the 

shaly splotches are light gray. 

With increase in the amount of clay the rock passes 

into a khaki-colored or light-greenish shale containing but little calcite. On weathered surfaces the shale 

shows the reddish or yellowish tints found in the shaly 

partings in limestone. Fossils are much more abundant in the shale than in any other portion of the formation, and nearly every bed contains at least a few phosphatic brachiopods of the genus Obolu8. 

Boundaries between the thin-bedded limestone and 

the more massive limestone are also gradational. The 

shaly partings and splotches become fewer, and the 

resultant rock is a resistant fine-grained to dense bluegray limestone with local small inclusions of shale. 

The more massive beds contain very little material 

that is insoluble in dilute acid. Included in the more 

massively bedded limestone are beds of darker-colored 

limestone containing abundant oval algal or concretionary growths. These beds are in some places finely 

oolitic and in others contain thin intraformational conglomerates with small fossil fragments, but such beds 

are neither abundant nor persistent. 

As might be expected from such gradations between 

the different lithologic varieties included in the forma- ' 

tion, there is but little persistence of individual beds 

along the strike. Three sections about a mile apart 

showed only a very generalized agreement in the succession of beds. This variation is especially true of the 

upper boundary of the formation. South of North Pass 

Canyon the base of the lowest massive dolomite in the 

overlying Young Peak dolomite has been considered to 

mark the upper limit. But the dolomite beds pinch 

out to the north, and on the north side of North Pass 

Canyon the top of the formation has been considered to 

be the base of thick-bedded limestones resembling in 

texture the dolomite beds of the Young Peak dolomite. I 

35311-35--2 

The following section, measured on the south side 

of Dry Canyon, is similar to the other sections measured, but it should be understood that the individual 

beds are not persistent. 

Section of Abercrombie formation on S01dh side of Dry Canyon 

Young Peak dolomite. 

Abercrombie formation: Feet 

Thin-bedded limestone, gray mottled _______ _ 188 

Shale____ __ ___ ___ _ __________ _ 46 

Thin-bedded limestone; thin shale beds at 96 and 

126 feet from top ___ _ 626 

Shale, calcareous at top __ 180 

Laminated gray limestone _______ . __ _ 154 

Shale, calcareous at top______ _______ _ 180 Thin~bedded limestone_____________________ _ 61 

Massive limestone, concretionary, oolitic, and with 

local conglomerates. 13 

Thin-bedded limestone_ _ __ . ___ _ 88 

Massive limestO!le, concretionary and oolitic _____ • 39 

Thin-bedded limesto;ne_ _ _ _ _ ___ _ 17 

Shale_____ __________ _______ _ 90 

Thin-bedded limestone __ _ 30 

Calcareous shale_ 90 

Thin-bedded limestone _____ _ 21 

Massive limestone, dolomitized_ 14 

Thin-bedded limestone_ 93 

Massive limestone, dolomitized _ 48 

Shale, calcareous at base____ _ 173 

Thin-bedded limestone __ 71 

Shale, calcareous at base___ _ 119 

Massive limestone, dolomitized_ __ _ _ - - - __ 62 

Thin-bedded limestone. ____ __ _ ______ _ 148 

Shale, calcareous at top; a few thin beds of quartzite 

at base_ _ _______ . __________ _ 147 

Limestone, dolomitized_ 10 

Sandy shale (top of Busby quartzite). 

2, 708 

Most of the massive limestone beds, as indicated in 

the section, have been partly dolomitized. The 

altered rock weathers to a light-brown color that 

sharply distinguishes it from the unaltered blue-gray 

limestone. The dolomite is coarser-grained and more 

resistant to weathering than the limestone. The 

dolomitized portions show no relations to bedding 

planes or to any depositional features but are localized 

along joints or minor faults, which strike in a general 

east-west direction and are in places accompanied by 

minor deposits of lead and silver. The alteration is 

clearly much later than the original formation of the 

sediments. 

Thickness.-Three measurements of the formation 

on the south and north sides of Dry Canyon and the 

north side of Sheep Canyon gave thicknesses, respectively, of 2,708, 2,080, and 2,680 feet. The first and 

third figures probably correspond closely with the 

true thickness of the formation. The second figure is 

much too low and is the result of overriding along a 

strike fault, which, on the ridge line, cuts the formation 

about 850 feet above the base. 
10 GOLD HiLL MINING DISTRIC1', UTAH 

Age and correlation.-Fossils collected from several 

of the shale zories show that the Abercrombie formation is of Middle Cambrian age. Dr. C. E. Resser, of 

the Smithsonian Institution, reports as follows upon 

the collections: 

12. 	At fork in Dry Canyon, 1 mile west of spring: 


Bathyuriscus productus (Hall and Whitfield). 


Obolus sp. 


Hyolithes sp. 


16. Ridge line on south side of Dry Canyon at altitude of 

about 7,900 feet: 

Zacanthoides sp. 

Bathyuriscus productus. 

Lingulella sp. 

This 	seems to represent the lowest horizon among the 

colleetions. The fauna corresponds with the Chisholm 

and Ophir. 

18. Just east of the 7,300-foot closed contour on the north 

side of Sheep Canyon: 

Paterina cf. P. utahensis. 

Elrathia sp. 

19. Just west of the 8,200-foot closed contour 

on the south side of Dry Canyon: Feet 

Micromitra sp. 

17. Saddle west of peak 8182, on south side of 

Dry Canyon: 

Obolus sp. 

Fucoids. 

Elrathia sp. 

All these are Middle Cambrian and apparently about the same horizon somewhere in the 

lower part. 

The formation is possibly equivalent to 

the Chisholm shale and the lower portions 

of the Highland Peak limestone at Pioche, 23 

the Teutonic, Dagmar, and Herkimer limestones at Tintic,24 and the Hartmann and 

Bowman limestones at Ophir. 25 These correlations are based almost solely on position in the stratigraphic column, as variations in lithology are characteristic of the Middle Cambrian in this 

portion of Utah. 

YOUNG PEAK DOLOMITE (MIDDLE CAMBRIAN) 

Distribution.-The Young Peak dolomite is named 

from Young Peak, on the north side of Dry Canyon, 

the summit of which is underlain by the formation. 

It crops out only in the southern part of the quadrangle 

in the Deep Creek Mountains. It forms a north-south 

band, somewhat interrupted by faulting, extending 

from the southern boundary to the north side of 

North Pass Canyon, where it curves to the east before 

disappearing beneath an overthrust plate. Half a 

"Westgate. L. G., Geology and ore deposits of the Pioche district, Nev.: 'G.S. 

Geol. Survey Prof. Paper 171, pp. 11-13, 1932. 

II Loughlin, G. F., Geology and ore depOSits of the Tintic mining district, 'Gtah: 

U.S. Geol. Survey Prof. Paper 107, pp. 27·28, 1919. 

2' Gilluly, James, Geology and ore deposits of the Stockton and Fairfield quad· 

rangles, Utah: U.S. Oeol. Survey Prof. Paper 173, pp. 12-15, 1932. 

mile to the east it reappears from beneath the plate 

and continues eastward for half a mile before being 

covered by later gravel. 

Lithology.··The Young Peak dolomite changes 

almost completely in lithologic character in the 4 

miles along which it is exposed. At the southern 

boundary it is composed almost entirely of dolomite, 

but in North Pass Canyon the same horizon is marked 

by limestone beds with only a few thin interbedded 

dolomite layers. This variation does not occur 

abruptly but is caused by a gradual interfingering 

northward of limestone at both the top and the bottom 

of the formation, until finally on the north side of 

North Pass Canyon only one dolomite bed about 5 

feet thick is exposed. 

The base of the formation as mapped is neither 

synchronous nor continuous. As far north as the 

head of Bagley Gulch it is mapped at the lowest 

locally exposed bed of massive gray dolomite. Owing 

600 

500 

400 

200 

100 

1<----1.3mi.--~--+--

2 

--- -->l<--0.6 mi.~0.5 mi.->f 

Dolomite 

~ 

FIGURE 2.-Sections of the Young Peak dolomite, showing the interfingering northward of limestone. 

1, South side of Dry Canyon; 2, north side of Dry Canyon; 3, north side of Sheep Canyon; 4, ridge 

between Bagley and Trippe Gulches; 5, ridge between Trippe Gulch and North Pass Canyon. 

to the successive lensing out of the lower beds northward, however, as indicated in the preceding paragraph and in figure 2, the base is represented not by 

one continuous bed but rather by higher and higher 

beds. Northward from Bagley Gulch, the dolomite 

beds thin out so rapidly that it was thought best to 

continue the boundary at the base of a series of massive limestones containing rodlike markings similar to 

those in the typical dolomite to the south. Although 

this is admittedly a compromise between lithologic 

mapping and synchronous mapping, it seemed to be 

the best course available. Mapping the continuation 

of the lowest dolomite bed northward would be impossible, because the interfingering limestone beds are 

indistinguishable, and poor exposures and numerous 

displacements by both major and minor faults preclude continuous tracing. To continue the mapping 

of the lowest dolomite bed as the base in the vicinity 

of North Pass Canyon would not only be difficult on 
GEOLOGIC FORMATIONS 11 

the scale of this map but would give a false suggestion 

of an overlap. The mapping adopted shows the 

horizon continuing conformably, as it does, and 

facilitates the delineation of the somewhat complex 

structure on the north side of North Pass Canyon. 

The upper contact of the formation, on the other 

hand, is sharp. It has been taken as the base of a 

dark-gray dolomite containing abundant nodules of 

black chert, which are as much as a meter in maximum 

diameter. This bed is overlain by a cream-colored, 

finely laminated dolomite. This sequence persists 

throughout the outcrop of the formation, and there 

are no beds containing such chert nodules lower in 

the section and none above until the upper portion of 

the Chokecherry dolomite is reached, about 3,000 feet 

higher, and here the characteristic laminated dolomite 

is missing. The beds above the upper boundary are 

essentially all limestones, many of them similar to 

beds in the Abercrombie formation. 

No section for the north side of North Pass Canyon 

is available because extreme crushing and minor 

faulting prohibit accurate measurement, but the base 

of the formation there is the same as that shown in 

section 5 of figure 2. The dolomite present in such a 

section would be limited to a 5-foot bed somewhat 

above the middle of the thickness shown. 

The typical rock of the dolomitic portion of the 

formation is a dark-gray to black dolomite spangled 

with short white rods of dolomite. The rods have an 

average length of about 10 millimeters and an average 

diameter of about 1 millimeter. They contain a little 

calcite, as shown by slight effervescence .with dilute 

hydrochloric acid. The dolomite matrix in which the 

rods occur is finely crystalline, the grains being 0.5 

millimeter or less in diameter. The rods are composed 

of grains of slightly larger size. The grains of both 

rods and matrix are readily distinguished by the 

naked eye, the rock thus differing from the dense 

limestones found beneath in the Abercrombie formation. Locally the spangled rock shows a mottling 

caused by irregular splotches of darker and lighter 

dolomite (pI. 5, A). The rods in such varieties are 

generally localized in the darker splotches. The 

mottled rock is generally found near the. top of the 

formation and is thinner-bedded than the rock below. 

Much of the thinner-bedded rock contains but few of 

the rods, and in many beds they may be entirely 

lacking. The lighter-colored portions of the mottled 

dolomite . generally effervesce weakly with dilute 

hydrochloric acid, showing that they contain some 

calcite. 

The limestone of the formation includes several 

varieties. A gray mottled limestone similar to that 

found in the Abercrombie formation makes up the 

greater part of the limestones interbedded with 

dolomite at the top and bottom of the formation. It 

is particularly abundant north of the road in North 

Pass Canyon. The massive limestone that takes the 

place of the dolomite in the middle of the formation 

is medium gray and extremely dense. Many of the 

beds contain whitc rods similar to those in the dolomite 

but composed of calcite. This fact is of some interest 

in that the rods have been thought to be fossil remnants, whose structure has been destroyed by subsequent dolomitization; but the structure of the rods 

where both they and the matrix are of calcite is as 

obscure as where both are of dolomite. If they represent organic remains of some sort, it is apparent that 

the lack of structure observed is due to some other 

factor than dolomitization. A few of the beds show 

bedding surfaces covered by a network of what appear 

to be fossil worm tracks. In many places these now 

consist of dolomite and are of lighter color than the 

rest of the rock. 

Age and correlation.~No determinable fossils have 

been found in the Young Peak dolomite. Because of 

its gradation into the underlying Abercrombie formation, whose age is known, it is thought to be Middle 

Cambrian. Similar lithology has been found in the 

Bluebird dolomite, of Middle Cambrian age, in the 

Tintic district,26 but a positive correlation with that 

formation is not made, because of the known lack of 

continuity in the lithology in the Gold Hill quadrangle. 

Correlation with formations in other districts in which 

this texture has not been noted must be limited to the 

suggestion that the Young Peak dolOInite is equivalent to the beds in the upper part of the Middle 

Cambrian sequence. 

TRIPPE LIMESTONE (MIDDLE CAMBRIAN) 

Distribution.-The Trippe limestone, named from 

Trippe Gulch on the south side of North Pass Canyon, 

crops out as a northward-trending band about 1,000 

feet wide, at an average distance of a mile east of the 

main divide of the Deep Creek Mountains. The outcrop extends northward from the southern border of 

the quadrangle to North Pass Canyon, on the north 

side of which the strike changes to northeast. About 

a quarter of a mile farther along the strike the formation disappears beneath a plate of overthrust rocks, 

and three-quarters of a mile east-northeast of this 

point it reappears with a strike of nearly due east, 

which changes to southeast before the beds are covered 

beneath the gravel that flanks the range. The formation has not been recognized on Dutch ~10untain. 

Lithology.-TheTrippe limestone is composed largely 

of thin-bedded limestones but includes also more massive limestones, a few dolomite beds, and one thin shale. 

Three sections were measured which show considerable variation in the lithologic succession, indicating 

that individual beds are generally lenticular. The 

" Loughlin, G. F., Geology and are deposits of the Tintic mining district, Utah: 

U.s. Gool. Survey Prof. Paper 101, p. 28, 1919. 
12 	 GOLD HiLL MINING DISTRICT, U'l'AH 

following section was measured on the ridge line on 

the south side of Dry Canyon. 

Section of Trippe limestone on ridge south of Dry Canyon 

Light-gray oolitic, cross-bedded dolomite (base of Lamb 

dolomite). 

Trippe limestone: Feet 

1. Thin-bedded limestone with gray mottlings__ _ _ _ _ 43 

2. Dark dolomite____________ ___________________ 19 

3. 	Thin-bedded limestone with pink and yellow mottli,ngs _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 98 

4. Oolitic 	limestone with local intraformational conglomerates and cross-bedding_ _ 13 

5. 	Thin-bedded limestone like no. 3. Thin shale near 

base___________ ____ ___ 75 

6. Cream-colored, finely laminated dolomite________ 1 

7. 	Thin-bedded limestone like no. 3 with local massive limestone____________________ ___ 46 

8. Coarsely crystalline massive light-gray limestone__ 19 

9. Laminated medium gray limestone_ _ . _. _. ___ 65 

10. Thin-bedded limestone like no. 3_ _ _ 133 

11. Gray dolomite_______________ _____________ _ 17 

12. 	Thin-bedded limestone like no. 1, massive darkgray dolomite 20 feet above base_ __ _ _ _ _ _ __ _ _ 79 

13. Finely laminated light-gray dolomite________ ___ 22 

14. Thin-bedded limestone like no. L_____ _ 30 

15. Thin-bedded gray dolomitic limestone____ 40 

16. Thin-bedded limestone like no. L____ ___ 22 

17. Gray dolomitic limestone__________________ _ 10 

18. Laminated cream-colored dolomite _ __ _ _ _ _ _ _ _ 5 

19. Dark-gray dolomite with black chert nodules_ __ 8 

Young Peak dolomite. 745 

Division 8 of this section is one of the few persistent 

beds and crops out as a low cliff tlU'oughout the exposure of the formation. Its presence is of assistance 

in determining the presence or absence of faults on the 

brush-covered side slopes of the canyons. 

Mottled limestone makes up the bulk of the formation and is similar in character to the mottled limestone of the two lower formations. The dolomite beds 

are dark gray, massive, and without the texture and 

markings characterizing those of the Young Peak 

dolomite. 

The most striking parts of the formation are the 

finely laminated white or cream-colored beds. These 

may be composed of either limestone or dolomite, 

although in no place was a single bed found to grade 

from limestone to dolomite. Locally these beds show 

phenomena that probably have resulted from the 

generation of gas in the carbonate mud prior to consolidation. In the specimen illustrated in plate 5, B, 

rupture was linear rather than through a vent of small 

cross section. The essential contemporaneity of such 

disturbances is proved by other specimens that show 

bedding continuing un distorted over the jumbled zone. 

One specimen was collected in which such a zone is seen 

to originate in a thin layer composed of tiny dolomite 

fragments in a limestone matrix. 

The base of the formation is taken at the base of a 

dark dolomite containing large lenses and nodules of 

black chert. This bed, though unusually continuous, 

apparently does not indicate any significant time 

break, for the limestone beds above are similar to 

those which are found interbedded with the dolomite 

beds of the Young Peak dolomite, below. 

The upper boundary of the formation has been 

placed at the base of a series of massive light-gray 

dolomites, many of which are oolitic and cross-bedded. 

The lithologic change is abrupt, but no other evidence 

of unconformity was determined. 

Thickne88.-A section measured on the ridge line 

south of Dry Canyon gave a thickness of 745 feet, 

and one on the ridge south of Sheep Canyon 765 feet. 

On the ridge south of North Pass Canyon, however, 

the thickness measured was only 660 feet. 

Age and correlation.-No fossils have been found in 

the Trippe limestone, but it is thought to be of Middle 

Cambrian age. This opinion is based on the lithologic 

resemblance of the mottled limestone members to 

those in the two underlying formations and on the 

lithologic break between it and the overlying Lamb 

dolomite which is believed to be of Upper Cambrian 

age. Whether the variations in thickness shown by 

the measured sections indicate an unconformity at the 

top of the formation or are due simply to minor faulting or concealed changes in dip is not known. An 

unconformity between the Middle and Upper Cambrian has not been previously reported in Utah, and 

the evidence in this area is not sufficient to consider 

that one exists. Walcott 21 believed that sedimentary 

barriers and local warpings are sufficient to explain 

the faunal change. 

The Cole Canyon dolomite in the Tintic district 28 

is possibly equivalent to the Trippe limestone. Each 

overlies a dolomite formation of similar texture, and 

the Cole Canyon contains laminated cream-colored . 

dolomite beds resembling those found in the Gold 

Hill quadrangle. Any further correlation is not 

warranted, owing to the lack of fossils and the known 

lithologic variations. 

LAMB DOLOMITE (UPPER CAMBRIAN) 

Distribution.-The Lamb dolomite is exposed as a 

faulted band, about a quarter of a mile wide, at 

various distances east of the divide in the Deep Creek 

Mountains. It extends in a general northerly direction 

from the southern boundary of the quadrangle to 

North Pass Canyon. North of this canyon the trend 

of the outcrop changes to northeast and then to east, 

and the width of the exposure ranges from a hundred 

yards to over half a mile. The formation in this area 

is highly shattered, owing to the fact that it overrides 

three of the lower formations and is itself overridden 

17 Walcott, C. D., The Cambrian and its problems, in Problems of American 

Geology, p. lIll, Yale University Press, 1915. 

•• Loughlin. G. F .• Geology and ore deposits of the Tintic district, Utah: U.S. 

Geol. Survey Prof. Paper 107, p. 28, 1919. 
----------------

GEOLOGIC 

by a higher formation. To the north a fault separates 

the formation from the Pennsylvanian Oquirrh formation. Beds included in the Lamb dolomite are found 

at several places on Dutch Mountain, but as it :vas not 

practicable to separate them from similar beds in the 

overlying Hicks formation, the two formations were 

mapped together as Upper Cambrian. 

The name is taken from Lamb Gulch, on the north 

side of DryCanyon, which is underlain by the formation. 

Lithology.-The base of the Lamb dolomite is 

marked by massive beds of light-gray dolomite. These 

are commonly composed of small rounded grains of 

darker dolomite in a matrix of much lighter colored 

• dolomite. The size of the grains ranges between 0.5 

and 1 millimeter, and they are thought to have been 

originally oolites, although no concentric structure is 

now discernible. Local concentrations of the darker 

grains in rude lenses essentially parallel to the bedding 

give a characteristically streaked appearance to many 

of the beds. Cross-bedding is commonly shown by 

the supposed oolitic beds. 

Interbedded are layers of pisolitie dolomite. The 

pisolites are rarely circular but usually elliptical in 

section and range in size from 1 to 10 millimeters. 

The larger ones show a poorly defined concentric 

structure, which, with the apparent gradation in size, 

makes it appear probable that the oolitic rocks described in the previous paragraph are really of that 

ongm. Locally the pisolites show asymmetric outgrowths, which, according to W. H. Bradley,29 of the 

Geological Survey, are similar in size and shape to 

algal growths found by him in pisolitic rocks occurring 

in the Green River formation in Wyoming. The 

matrix is a light-colored dolomite that is, in many 

places, recrystallized and shows shining cleavage faces. 

The pisolites are usually oriented with the longer axis 

parallel to the bedding. The pisolitic and oolitic roeks 

make up the basal 500 feet or so of the formation and 

recur as thinner zones throughout it. 

The bulk of the formation, however, is composed of 

a light to medium gray dolomite mottled by patches 

of darker dolomite containing white rods, resembling 

closely parts of the Young Peak dolomite. In many 

places the darker dolomite appears to occur as boulders 

in the lighter-colored matrix, but in others the contact 

between the two varieties is indefinite and apparently 

the result of a replacement of the darker variety by the 

lighter. That this is the probable explanation is supported by the presence in several places of continuous 

beds of the dark, rod-speckled dolomite. 

Throughout the exposure in the Deep Creek Mountains the greater part of the formation has been 

recrystallized and bleached to a white resistant dolomite containing numerous vugs lined with dolomite 

.. Personal communication. 

FORMATIONS 13 

crystals. Locally, the old texture may be faintly 

discerned on the weathered surfaces, but in most 

places no traces of it remain. 

The top 150 feet of the formation is quite different 

in character from the lower part. Thin-bedded dolomite with partings of yellow or red sandy shale, together with a few massive dolomite beds, compose the 

lower 100 feet or so of this zone. The change from the 

more massive beds is not abrupt. Locally, the thinbedded rocks are dolomitic limestones, and in a few 

places they are essentially limestones. The limestone 

beds resemble somewhat the thin-bedded mottled 

limestones of the Middle Cambrian, except that the 

partings are rather more sandy than shaly. The top 

25 to 50 feet of this zone is made up of a reddishweatheling fine-grained sandstone, which is yellowish 

on fresh fracture. It is rather impure, containing 

moderate amounts of mica and dolomite, and is not 

sharply set off from the dolomites below. The sandy 

partings increase in thickness until they form the bulk 

of the rock. The top of this sandstone has been taken 

as the top of the formation. The sandstone is probably 

continuous from the south boundary of the quadrangle 

as far north as the ridge on the north side of Sheep 

Canyon. On the north slope of this ridge, however, 

the bed apparently lenses out and is replaced by 

another sandstone about 100 feet higher stratigraphically. This higher bed has been mapped as the top 

of the formation for the remainder of the exposure of 

the formation in the Deep Creek Mountains. 

Thickness.-Three measurements of the Lamb dolomite in the Deep Creek Mountains gave thicknesses of 

1,080, 1,035, and 1,020 feet. These variations may be 

easily explained by changes in strike and dip that are 

concealed owing to poor exposures and by minor 

faulting. The true thickness is probably not far from 

1,050 feet. . 

Age and correlation.-As no fossils have been found 

in the formation, its age is not definitely known. It is, 

however, similar in lithology to the overlying formation, and the sandstone beds used to delimit the two 

are probably lenticular. This, combined with the 

sharp change in lithology at the base of the formation, 

makes it probable that the age of the Lamb dolomite 

is the same as that of the overlying Hicks formationUpper Cambrian. Because of the lack of fossils the 

Lamb is difficult to correlate with any degree of certainty, but it is probably equivalent in age to the 

lower 800 feet of the Mendha formation at Pioche 30 

and the Opex dolomite at Tintic.31 Beds of similar 

lithology are lacking at the base of the Upper Cambrian 

in both the Eureka and the House Range sections. 

.. Westgate, L. G., Geology and are deposits of the Pioche district, Nev.: U.S. 

Geol. Survey Prof. Paper 171, pp. 13-14, 1932. 

'I Loughlln, G. F., Geology and are deposits of the Tintic minlng district, Utah; 

U.S. Gaol. Survey Prof. Paper 107, p.29, 1919• 

....~-.~------- .....-----~...------~---. 
14 GOLD HILL MINING DISTRICT, UTAH 

HICKS }<'ORMATION (lJI>PER CAMBRIAN) 

Distr'ib1ltion.-The Hicks formation takes its nume 

from Hicks Gulch, in North Puss Canyon. This 

locality is neHr the northern limit of the chief exposure 

of the formation, which extends as a band, made 

discontinuous by transverse faults, east of the divide 

of tbe Deep Creek Mountains. A small wedge of the 

formation is exposed on the north side of North Pass 

Canyon, north of the fault that limits northward the 

main outcrop. Beds belonging to the formation are 

also found at several places on Dutch Mountain, 

but these beds have been included with the underlying Lamb dolomite and mapped as undifferentirJed 

Upper Cambrian. 

Lithology.--The lithology of the Hicks formation is 

in part similar to that of the Lamb dolomite. Oolitic, 

streaked, pisolitic, and mottled dolomites make up a 

large portion of the formation. A specimen of the 

pisolitic type, ohtained near the base of the formation, 

is illustrated in plate 5, O. Some of these heds contain 

tiny nodules of white chert, which are neither abundant 

nor conspicuous. 

In addition to the dolomites, there are several len ticular beds of sandstone and of limestone, and in one 

place a thin bed of shale was noted. The presence of 

the several rock types and the fact that the limestones 

are abundantly fossiliferous were the main factors in 

separating the formation from the one below. 

The following section, measured on the ridge on the 

north side of Sheep Canyon, is fairly characteristic of 

the formation: 

Section of Hicks formation on north side of Sheep Canyon 

Base 	of Chokecherry dolomite: Mottled dolomite with 

nodules of black chert, local conglomerates, aud cro~sbedding. 

Hicks formation: 	 Peet 

1. Mottled dolomite, locally calcareous ____ _ 90 

2. Bleached and recrystallized massive dolomite_ 33 

3. Sandy shale _ _ _ ______ _ 38 

4. Bleached and recrystallized massive dolomite __ _ 73 

5. Massive oolitic gray dolomite_____ _ 129 

6. Thin-bedded sandy limestone and ca.lcareous sandstone_ _ _____ _ ________ _ 79 

7. Thin-bedded sandy dolomite ________ _ 34 

8. Massive oolitic, pisolitic, and rod-speckled dolomite___ .. ________ __________ _ 38 

9. Thin-bedded oolitic sandy dolomite ___ _ 24 

10. 	 Massive oolitic gray dolomite .. _ _ _ _ _ _ _ __ 14 

11. 	Thin-bedded oolitic sandy dolomite; weathers to 

shades of talL _______ ' _ 28 

12. 	 Medium to dark gray cross-bedded streaked oolitic 

dolomite; many pisolitic laycrs at base; ncar the 

top are a !lumber of beds of dark dolomite with 

numerous small white rods_ _ _ _ _ _ _ ______ _ 173 

Sandstone at .top of I"nnb dolomite. 

753 

Three other sections were measured in the Deep 

Creek Mountains. They are of the same general chara,cter as the one given above but show that the individual beds are extremely lenticular. For example, the 

limestone zone (no. 6 of the section) on the north side 

of Sheep Canyon is 311 feet above the base of the 

formation and 79 feet thick, whereas half a mile to the 

north it is 171 feet thick and starts 215 feet above 

the base, and a little more than a mile to the south it 

was not found at all. 

No sections of the formation were found that were 

free from recrystallized and bleached members such as 

nos. 2 and 4 in the section given above. These occur 

at very different horizons and in varying amounts. 

On the south side of Sheep Canyon, for example, the 

upper 315 feet has been thus altered. Like similar 

beds in the Lamb dolomite, these show throughout 

indistinct remnants of the original texture. 

The upper limit of the formation has been taken as 

the base of the lowest dolomites containing nodules and 

bands of black chert. This zone usually includes local 

dolomite conglomerates and cross-bedded layers. The 

exact contact is difficult to find because of poor exposures and rather general recrystallization. 

Thickness.--The thicknesses measured were variable, 

ranging from 1,200 feet on the south side of Dry Canyon through 890 and 750 feet on the south and north 

sides of Sheep Canyon, respectively, to 590 feet at the 

head of North Pass Canyon. 

Age and correlation.-Fossils found in one of the 

limestone members at the head of North Pass Canyon 

have been reported upon by Dr. C. E. Resser, of the 

Smithsonian Institution, as follows: 

M-3.· Half a mile east of peak 8135, in North Pass Canyon: 

Pseudagnostus sp. 

Dunderbergia sp. 

Obollls sp. 

20. 	 Ridge line on llorth side of Dry Canyon: 


Acrotreta sp. . 


These suggest a possible correlation with the Secret CanVOl! 

shale. It represents a lower Upper Cambrian horizon, at ~ny rate. . 

This horizon is probably unrepresented in the Tintic 

district, where there are less than 400 feet of Upper 

Cambrian beds. The upper part of the Mendha formation at Pioche 32 is probably of equivalent age. 

UNCONFORMI'I'V AT 'rop OF UPPER CAMBRIAN 

The progressive northward thinning of the Hicks 

formation from 1,200 feet to less than 600 feet in a 

distance of 3?~ miles indicates a pronounced unconformity at its top. The basal Ordovician beds show 

local dolomite conglomerates and abundant shallowwater phenomena, such as cross-bedding. No sandstone, however, has been recognized as being at the 

contact. The only criterion that was found of assistance in the mapping is the universal occurrence of 

dark chert in the Ordovician sediments. 

~'Westgat€. L. G., Geology and ore depo$its of the Pioche district, Nev.: U.S. 

Geol. Survey Prof. Paper 171, pp. 13-14, 1932. 
ORDOVICIAN SYSTEM 15 

The presence of an erosional unconformity at the 

base of the Ordovician has not been generally recog~ 

nized in the Great Basin region. In the Tintic 

district 33 one was recognized but considered to be of 

only local significance. Earlier Richardson 34 had 

described an unconformity at this horizon in the 

Randolph quadrangle, in northern "C"tah, resulting in 

the removal of over 800 feet of "C"pper Cambrian beds. 

In the House Range and at Eureka, Xev., however, 

Walcott has considered the Ordovician to overlie the 

Upper Cambrian conformably, and in a general 

review of the subject 35 he notes that the Upper Cam~ 

brian formations in the Cordilleran region pass into 

the overlying beds without apparent stratigraphic 

break. 

The proof of a definite erosional unconformity at 

the top of the Upper Cambrian in three localities so 

widely separated as the Tintic district, northern Utah, 

and Gold Hill, however, seems to indicate that it is 

more than a local occurrence, and it is probable that 

future work, with carefully measured sections, will 

show that the unconformity is of wider extent than is 

now recognized. 

ORDOVICIAN SYSTEM 

CHOKECHERRY DOLOMITE (I,OWER ORDOVICIAN) 

Distribution.-The Chokecherry dolomite, named 

after Chokecherry Canyon, just beyond the south edge 

of the quadrangle, crops out in the Deep Creek 

l'.1ountains, where it is exposed as a discontinuous 

band, of variable width, as far north as North Pass 

Canyon. South of the pass at the head of Dry 

Canyon, where the base of the formation is just east of 

the crest of the range, its width is about three~quarters 

of a mile, owing to the fact that the surface slope is 

nearly equal to the dip of the beds. The wide outcrop, 

most of which lies west of the crest, is terminated by a 

transverse fault in Dry Canyon. North of the fault 

the outcrop lies east of the crest and is much narrower, 

a quarter of a mile being the maximum width. A few 

transverse faults offset its northerly course, and it is 

finally terminated by a large transverse fault in Xorth 

Pass Canyon. The formation is absent on Dutch 

Mountain, where Upper Ordovician dolomite rests 

upon beds of Upper Cambrian age. 

Lithology.-The Chokecherry dolomite is charac~ 

terized by the presence of considerable silica, found 

both as nodules and as layers of chert, usually darkgray to black, and as sandy laminae between thin beds 

of dolomite. The lower beds are, as a rule, rather 

massive dark mottled dolomite, locally oolitic and 

" Loughlin, G. }<'., Geology and ore deposits of the Tintic mining district, Utah: 

U.S. Geo!. Survey Prof. Paper lOi, p. 80, 1919. 

!4 Richardson. G. B.. The Paleozoic section in northern Utah: Am. Jour. Sci., 

4th ser., vol. 36, p. 408, lI1l3. 

"Walcott, C. D., The Cambrian and its problems. in Problems of American 

geology, p. lin, Yale University Press, 1915. 

cross-bedded and containing thin lenses of dolomite 

conglomerate. Small black chert nodules are found 

throughout. These beds are supplanted higher in the 

formation by thinner-bedded dolomite with sandy 

laminae, or locally by bands of dark chert. In a few 

places the laminae become sufficiently thick to form 

lenses of sandstone. One bed, near the top of the 

formation, that has been found to be continuous in the 

southern part of the exposure in the Deep Creek 

Mountains is a light-gray dolomite filled with siliceous 

concretions about the size and shape of a gooseberry. 

The formation has been particularly susceptible to 

the bleaching and recrystallization that has affected 

the two lower formations, described above. In most 

of the sections examined between a third and a half of 

the formation has been thus altered. 

This alteration, combined with poor exposures of the 

thin-bedded dolomites at the top of the formation, 

makes the determination of the upper boundary uncertain. Where best exposed the basal beds of the 

overlying Fish Haven dolomite are seen to be medium 

thick bedded dolomites, free from the sandy laminae of 

the lower dolomites and containing but little chert. In 

mapping, therefore, the boundary was placed at the top 

of the highest sandy or cherty float. 

Thickness.-The formation shows a rather notable 

variation in thickness from the southern part of the 

quadrangle northward. On the south side of Dry 

Canyon at least 1,000 feet is exposed; on the north side 

of Sheep Canyon, 890 feet; and at the head of North 

Pass Canyon, 850 feet. On Dutch Mountain the 

Chokecherry dolomite is absent, and dolomite of Upper 

Ordovician age rests upon Upper Cambrian dolomite. 

Age and correlation.---Scanty fossil collections made 

by Edwin Kirk, of the Geological Survey, have been 

determined by him as follows: 

TN-26 37. East of saddle on ridge between peaks 8550 and 

8350, on north side of Dry Canyon, and also on ridge line of 

peak 8491, at head of Dry Canyon. Scaevogyra? sp. 

The few gastropods in this lot do not permit exaet age 

determination, and as yet we know of no other horizon with 

which it may be correlated. It may safely be considered 

early Lower Ordovician, however. 

Rocks of Lower Ordovician age are found in many 

places in the Great Basin. In each area, however, the 

lithology is, as a rule, markedly different from that of 

neighboring areas, and the only reliable method of 

correlation is by means of the contained fossils. The 

fossil evidence indicates that the Chokecherry dolomite represents only a portion of Lower Ordovician 

time. As in other districts higher beds may be present, 

exact equivalents are difficult to determine, but in 

general the Chokecherry dolomite may be considered 

of about the same age as the Ajax and Opohonga limestones at Tintic,36 the Garden City limestone in the 

" Loughlin, G. F., Geology and ore deposits of the Tintic mining district, Utah: 

U.S. Geol. Survey Prof. Paper 107, pp. 31-33. 19l\l. . . 
16 GOLD HILL MINING DISTRICT, UTAH 

Randolph quadrangle/7 the Yellow Hill limestone at 

Pioche,ss part of the Grampian limestone in the S~n 

Francisco region,39 and the basal part of the Pogomp 

limestone of the Eureka district.40 

UNCONFORMITY AT BASE OF UPPflR ORDOVICIAN 

The variable thickness of the Chokecherry dolomite 

in the Deep Creek Mountains and its apparent absence 

on Dutch Mountain indicate an unconformity between 

it and the overlying Fish Haven dolomite, of Upper 

Ordovician age. Further evidence of an unconformity 

is indicated by the presence in the southern part of 

the range of a Lower Ordovician fauna that resen:bl~s 

that of a higher formation than the beds found wIthin 

the quadrangle; 41 and on the reported presence to the 

south of a quartzite that is apparently equivalent to 

the Eureka quartzite found in the Middle (?) Ordovician of Nevada.42 

This unconformity has been reported from three 

other localities-Eureka, Nev.,43 northern Utah,H and 

southeastern Idaho.45 In all three the unconformity is 

shown by the varying thickness of an under~y~ng 

quartzite, which is, in the Utah and Idaho localItIeS, 

of Chazy (?) age. The quartzite in Nevada is probably 

of about the same age. The hiatus represented by the 

unconformity is thus much greater at Gold Hill than 

it is to the north or south, but whether the absence of 

the high Lower Ordovician beds is due to erosion ~r ~o 

nondeposition is not clear. The latter hypothesIS IS 

perhaps more probable, in view of the lack of conglomerate or other clastic rocks at the base of the Upper 

Ordovician sediments. 

At Eureka and in the northern Utah area the unconformity is shown by the varying thickness of an underlying quartzite which is of Chazy (?) age in the Utah 

locality but is un fossiliferous at Eureka. In southeastern Idaho the quartzite of Chazy (?) age appears 

to lie conformably beneath the Fish Haven, but a 

considerable time break is required by the absence of 

beds containing faunas that in other localities intervene 

between the rocks of Chazy age and those of Fish 

Haven age. 

"Richardson, G. B., The Paleozoic section in northern Utah: Am. Jour. Sci., 

4th ser., vol. 36, p. 408, 1913. 

18 Westgate, L. G., Geology and ore deposits of the Pioche district, Nev.: U.S. 

Geol. Survey Prof. Paper 171, p. 14,1932. 

., Butler, B. S., Geology and ore deposits of the San Francisco region, Utah: 

U.S. Geol. Survey Pro!. Paper 80, p. 30, 1913. 

"Hague, Arnold, Geology 01 the Eureka district, Nev.: U.S. Geol. Survey Mon. 

20, p. 13, 1892. 

.. Butler, B. S., Ore deposits of Utah: U.S. Geol. Survey Prof. Paper 111, p. 471, 

1920. 

.. Reagan, A. B .• Geology of the Deep Creek region, Utah: Salt Lake Min. Rev., 

vol. 19, June 30, 1917, p. 25. 

"Hague, Arnold, Geology 01 the Eureka district, Nev.: U.S. Geol. Survey Mon. 

20, p. 56, 1892. 

.. Richardson, G. B., The Paleozoic section in northern Utah: Am. Jour. Sci., 

4th ser., vol. 36, p. 408, 1913. 

"Mansfield, G. R, Geology and geography of southeasttlrn Idaho: U.S. Geol. 

Survey Prot. Paper 152, p. 58, 1927. 

FISH HAVEN DOLOMITE (UPPER ORDOVICIAN) 

Distribution.-The Fish Haven dolomite crops out 

as a narrow band underlying the massive Laketown 

dolomite in the Deep Creek Mountains as far north 

as North Pass Canyon. In this region it is in general 

poorly exposed, being covered by the debris from the 

resistant formation above. Outcrops of the formation 

also occur at three places on Dutch Mountain--on the 

southeast flank, from Pool Canyon to the south side 

of the canyon in which the Spotted Fawn mine is 

located; on the north flank, in Royal Gulch; and on 

the northwest flank, in the lower foothills. In these 

three localities the formation, although cut by numerous faults, is much better exposed than in the 

southern part of the quadrangle. 

The name" Fish Haven" is that given by Richardson 46 to rocks of similar age and lithology in northern 

Utah. 

Lithology.-The Fish Haven dolomite is composed of 

moderately thick to thick-bedded dolomite, usually 

dark gray, with but little chert. On Dutch Mountain 

lighter-colored beds are found in the middle part of the 

formation, but the color is, in part at least, due to 

bleaching. In general the mottling and other textural 

features so abundant in the formations above and 

below are lacking, but several beds show lighter gray 

splotches in a matrix of dark gray. Some beds also, 

near the top of the formation, contain vugs filled with 

white crystalline dolomite. On Dutch Mountain the 

basal bed is characterized by numerous small silicified 

brachiopods (Rhynclwtrema argenturbica), which greatly simplify the mapping of the boundary. This bed 

was not found in the Deep Creek Mountains. 

The lower contact is well exposed on Dutch Mountain and at a few places in the Deep Creek Mountains. 

This contact is irregular in detail, but nowhere could 

it be shown that any notable amount of the Hicks formation had been removed before the deposition of the 

Fish Haven. Locally the basal beds of the overlying 

Laketown dolomite are dolomite conglomerates, but in 

most places they are dolomite sands, with wavy bedding planes and numerous fragments of Silurian corals 

and brachiopods. 

Thickness.-The thickness of the formation is surprisingly constant over the whole area. On Dutch 

Mountain 278 feet was found, on the ridge between Dry 

Canyon and Sheep Canyon 253 feet, and at two other 

poorly exposed localities in the Deep Creek Mountains 

about 250 feet. 

Age and correlation.-Fossil collections were made 

both on Dutch Mountain and in the Deep Creek 

Mountains. They have been identified by Edwin 

.. Richardson, G. B., The PaleOZOiC section in northern Utah: Am. Jour. Sci.. 

4th ser., vol. 36, pp. 409-410, 1913. 
SILURIAN SYSTEM 17 

Kirk, who assigns them to the Upper Ordovician. 

His report is as follows: 

TN-26 33. 1 mile south of peak 7800 of Dutch Mountain, 

about 3 miles north of Gold Hill: 

Halysites gracilis (Hall). 

Streptelasma trilobatum Whiteaves. 

Calapoecia cf. C. anticostiensis Billings. 

Rhynchotrema capax Conrad. 

Rhynchotrema argenturbica (White). 

Dinorthis subquadrata Hall. 

Zygospira recurvirostris (Hall). 

TN-26 36. Just west of saddle between peaks 8550 and 

8359 on ridge on north side of Dry Canyon near hea.d: 

Streptelasma. trilobatum Whiteaves. 

Streptelasma sp. 

Columnaria sp. 

This horizon is correlative with the upper portion of the 

Montoya limestone of Texas and New Mexico, the Fish Haven 

limestone of northern Utah, and the upper portion of the Bighorn dolomite of Wyoming. Rocks of equivalent age occur in 

the lower part of the Lone Mountain limestone of the Eureka 

district. 

The upper part of the Bluebell dolomite at Tintic 47 

is also of this age, as is the Ely Springs formation at 

Pioche, N ev. 48 

UNCONFORMITY AT TOP OF UPPER ORDOVICIAN 

In the Gold Hill quadrangle there is little physical 

evidence of an unconformity between the Fish Haven 

dolomite and the overlying Laketown dolomite. 

The Fish Haven is remarkably constant in thickness 

throughout the area, and the dolomite conglomerate 

and wavy contact found at the base of the Laketown 

dolomite are no better defined than similar features 

within many of the lower Paleozoic formations. Further, the regional variation in thickness o~ UPPder 

Ordovician sections that are overlain by Silunan be s 

is relatively slight. For example, the thickness at 

Pioche, Nev., is 525 feet; at Gold Hill, 260 feet; 

and in the Randolph quandrangle, Utah, 500 feet. In 

no one of these localities, moreover, does there seem 

to have been any notable amount of erosion before 

middle Silurian time. The absence of late Upper 

Ordovician and early Silurian faunas at all these localities, however, implies that there has been ~ con~iderable hiatus in sedimentation throughout thIS regIOn. 

SILURIAN SYSTEM 

LAKETOWN DOLOMITE 

Distribution.--The Laketown dolomite crops out 

prominently in the Deep Creek Mountains, forming 

the crest of the range from Dry Canyon north to North 

Pass Canyon. The width of this outcrop varies 

greatly, owing in part to the approximate coincidence 

of the dip of the beds and the slope of the surface west 

"Loughlln, G. F., Geology and ore deposits of the Tlntic mining district, Utah: 

U.8. Gaol. Survey Prof. Paper 101, p. 35, 1919. 

II Westgate, L. G., Geology and ore deposits of the Pioche district, Nev.: U.S. 

0601. Survey Prof. Paper 171, p. 16, 1932. 

of the crest. South of Dry Canyon the fonnation 

is found entirely on the western flank of the range, 

where it forms the 7,662-foot hill between the forks 

of Simonson Canyon. A narrow band is present on 

the north side of North Pass Canyon. It is terminated 

both to the north and south by faults. Two small 

outcrops partly surrounded by gravel are also exposed 

on the southern flanks of Blood Mountain. 

On Dutch Mountain the fonnation is exposed overlying the Fish Haven dolomite from Pool Canyon 

on the south to Spotted Fawn Canyon on the north. 

It is also present in Royal Gulch and in the foothills 

of the northwestern slope of Dutch Mountain. 

The name of the fonnation is the same as that used 

by Richardson 49 for rocks of similar age in northeastern Utah. 

Lithology.-The lower half of the Laketown dolomite 

is dark gray, rather massively bedded, and notably 

fossiliferous. Much of the rock is mottled or laminated, and such beds contain intrafonnational conglomerates. The appearance of these conglomerates 

was so striking that in the field they were distinguished 

by the name "marble cake" dolomite (pI. 5, D). 

Sections of a pentameroid brachiopod (Virgiana sp.) 

may be found throughout this zone, and one persistent bed, about 100 feet above the base, is largely made 

up of this fossil. 

Above this dark dolomite is 350 to 400 feet of 

medium-gray massive dolomite. This zone is almost 

lacking in fossils and has none of the textural features 

so abundant in the lower beds. Most of the beds are 

rather coarsely crystalline, and a few contain vugs 

filled With white, well-crystallized dolomite. 

This zone is overlain by another of massively bedded 

dark-gray to black dolomite, which also shows no unusual textural features except local thin chert stringers. 

It contains abundant fossil corals, which are locally 

silicified. This zone is about 150 to 200 feet thick. 

Above it from Sheep Canyon southward is a medium 

to light gray coarsely crystalline dolomite, which 

locally contains a bed crowded with large brachiopods 

of the genus Trimerella. This dolomite is not found 

to the north. 

The upper contact of the formation is unconfonnable, the basal beds of the overlying Sevy dolomite 

clearly occupying depressions in the Laketown dolomite and resting upon successively lower beds of the 

Silurian northward. The top light-gray member, as 

noted above, is not present in the northern exposures 

of the fonnation in the Deep Creek Mountains. 

Thickness.-A section of the formation measured on 

the ridge between Dry Canyon and Sheep Canyon was 

970 feet thick. No other satisfactory measurements 

of the thickness were made, because of the presence of 

strike faults or because of poor exposure; but it is 

" Richardson, G' B., Paloo'oiesection in northern Utah: Am. Jour. Se!., 4th ser., 

vol. 36, p. 410, 1913. 
18 GOLD HILL MINING DISTRICT, UTAH 

thought that the limits for the thickness in the Deep 

Creek Mountains within the quadrangle are 1,200 and 

850 feet. No estimate of thickness on Dutch Mountain 

can be made, for the top is nowhere exposed, a fault 

contact with the Mississippian being found at all 

points. 

Age and correlation.-The Laketown dolomite is 

abundantly fossiliferous throughout. Collections were 

made at various horizons, and these have been reported 

upon by Edwin Kirk as follows: 

M4. About 100 yards due east of peak 8135, on south side of 

North Pass Canyon. 544 feet above base of formation: 

Halysitcs catenularia (Lin-I Zaphrentis sp. 

naeus). Favosites sp. 

M13. Near head of Sheep Canyon, on north side, about 150 

feet below top of formation: 

Sections of brachiopod, probably Trimerella sp. 

TN-26 22. Three-quarters of a mile north of peak 8550, 

Sheep Canyon, near base of formation: 

Virgiana? sp. 

TN-26 32. Crest of peak 8135, at head of North Pass 

Canyon: 

Halysites eatcnularia (Lin- Syringopora, 2 sp. 

naeus). Zaphrentis sp. 

Halysites, 2 sp. Favositcs sp. 

Coenites sp. 

TN-2634. Slope half a mile south of peak 8291, on north 

!.'lide of Sheep Canyon: 

Halysites catenularia (Lin-I Trimerella sp. 

naeus). 

TN-2635. South slope of peak 8550 on north side of Dry 

Canyon, near head: 

Halysites catenularia (Lin- Zaphrentis, 2 sp. 


naeus). 
 Favosites sp. 


Halysites sp. 
 Virgiana? sp. 

Syringopora, 2 sp. 

TN-26 39. 1 mile south-southeast of peak 7800, Dutch 

Mountain: 

.l<'avosites sp. (digitate form). I Amplexus sp. 

Zaphrentis sp. Heliolites sp. 

TN-2640. 4,500 feet east-northeast of peak 8135, North 

Pass Canyon: 

Favosites sp. (digitate fOrm)'j Heliolites sp. 

Zaphrentis gp. 

Gray dolomite above typical Silurian on ridge at head of 

south branch of Sheep Canyon, half a mile northwest of peak 

8550: 

Huronia sp. 

This formation may be considered of Niagaran age. It is 

correlative in part with the Fusselman limestone of Texas and 

New Mexico, the LaketowD dolomite of northern Utah, and 

probably the upper portion of the Lone Mountain limestone of 

the Eureka district. 

UNCONFORMITY BETWEEN SILURIAN AND DEVONIAN 

The truncation of beds at the top of the Laketown 

dolomite, as shown by the disappearance northward of 

the upper light-gray, coarsely crystalline member, and 

the local presence, in the basal Devonian formation, of 

conglomerate containing pebbles of the underlying 

Silurian formation, leave little doubt that there is a 

pronounced unconformity between the Laketown dolumite and the Sevy dolomite. An unconformity at this 

point has not previously been reported from the Great 

Basin or adjacent regions, chiefly because sediments of 

either Silurian or Devonian age or both are commonly 

lacking. Both series have been reported from three 

localities in Utah and Nevada-the Randolph quadrangle, Utah,50 Pioche, Nev./I and Eureka, Nev. 52 

In the Randolph quadrangle the succession is said to 

be apparently conformable; at Pioche the two are not 

in contact; and at Eureka the contact is gradational. 

It would thus appear that the unconformity in the 

Gold Hill quadrangle is local in extent, but it is perhaps 

significant that no late Silurian faunas have been 

reported from either Eureka or the Randolph 

quadrangle. 

DEVONIAN SYSTEM 

SEVY DOLOMITE (MIDDI,E DEVONIAN) 

Distrib1ttion.-The Sevy dolomite, named from 

Sevy Canyon, is exposed only in the Deep Creek 

Mountains, generally being found on the west flank of 

the range. The most southerly exposure is in the south 

branch of Simonson Canyon, on the southern boundary 

of the quadrangle. This is of small extent and is separated on the north from the Laketown dolomite by a 

northwestward-striking fault. Outcrops occur also in 

the north branch of Simonson Canyon, on the north 

side of the Dry Canyon transverse fault. ]'rom this 

place the formation extends, with only minor interruption by faulting, in a direction a little east of north. 

Lithology.--The Sevy dolomite is remarkably homogeneous throughout the area of outcrop. The typical 

rock is a well-bedded mouse-gray dolomite in layers 6 

to 12 inches thick and weathers to a very light gray. 

It is of extremely dense texture and has a conchoidal 

fracture. In most of the beds a faint lamination 

parallel to the bedding is visible, in part at least, 

because of slight differences in color in adjoining 

laminae. A few beds of darker dolomite occur near 

the top of the formation, and locally there are present 

beds containing tiny nodules of light-colored chert. 

The basal beds show the only notable variations in 

character from the main mass of the formation. The 

lower 30 feet includes in most places lenticular beds 

from 1 to 5 feet thick of medium gray, rather coarse 

grained dolomite sand, which is similar in color and 

texture to the top member of the Laketown dolomite. 

Some of these lenses contain numerous pebbles or 

boulders of dolomite. Some of the boulders are subangular in outline and consist of dark dolomite similar 

in lithology to various beds of the Laketown dolomite. 

The greater number, however, are sharply angular 

" Richardson, G. B., Paleozoic section in northern Utah: Am. Jour. Sci., 4th ser., 

vol. 36, p. 411, 1913. 

'1 Westgate, L. G., Geology and ore deposits of the Pioche district, Nev.: U.S. 

Oeol. Survey Prof. Paper 171, pp. HH9, 1932. 

"Hague, Arnold, Geology of the Eureka district, Nev.: U.S. Gool. Survey Mon. 

20, p. 63, 1892. 
DEVONIAN 

thin wedges or blocks of a light-gray dolomite identical 

with the enclosing beds. The lamination of the pebbles 

shows that they have been considerably rotated. The 

apparent anomaly of a conglomerate containing 

boulders of the younger rock in a matrix of material 

from the older rock may perhaps be explained as 

follows: The waters in which the Sevy dolomite was 

deposited were pitrt of an advancing shallow sea, 

which was, at the locality and time represented by 

these sediments, just beginning to spread over the older 

rocks. Occasional t>evere storms broke up the partly 

consolidated sediments just drposited and at the same 

time swept in abundant fine-grained debris and a few 

larger boulders from the nearby shore composed of 

Silurian rocks. On the cessa.tion of the storm, the 

material was deposited, and the resulting rock was 

similar to the material here described. 

Thickne88.-0n the north side of Sevy Canyon the 

formation is 4';0 feet thick. The rocks here are well 

exposed and apparently not faulted. On the north 

side of Simonson Canyon 600 feet of beds were measured. The formation at this place is poorly exposed, 

however, and there may be some repetition of beds by 

faulting. Some variations in thickness are to be 

expected in an overlapping formation such as the Sevy 

dolomite, and the difference of 150 feet between the 

two measurements may be a difference in original 

deposition. 

Age and correlation.--The only fossils found in the 

Sevy dolomite were small crinoid stems at a few 

horizons and several poorly preserved gastropods near 

the base. None of these, according to Edwin Kirk, 

who examined the formation in the field, are sufficiently diagnostic for determination of age. The formation grades into the overlying Simonson dolomite, 

which contains a Middle Devonian fauna. The Sevy 

dolomite is therefore considered to be Devonian and 

probably Middle Devonian. 

SIMONSON DOLOMITE (MIDDLE DEVONIAN) 

Di8tribution.-The Simonson dolomite, named from 

Simonson Canyon, on the west side of the Deep Creek 

Mountains near the southern boundary of the quadrangle, is exposed chiefly in these mountains. The 

only complete sections are found on the west side of the 

range, where the formation overlies the Sevy dolomite 

and is of similar extent. Smaller outcrops composed of 

portions of the formation occur at three other places. 

The largest of these is on the north side of North Pnss 

Canyon, where, south of a large fault separating lower 

Paleozoic from Pennsylvanian rocks, a few hundred 

feet of the Simonson dolomite rests, with fault contact, 

upon beds of the Laketown dolomite. A smaller area 

of the formatiop. is located in North Pass Canyon a 

quarter of a mile west of the branch road leading up 

Bagley Gulch. This is surrounded by gravel. A 

small exposure is also found on the north side of Dutch 

Mountain. 

SYSTEM 19 

Lithology.--The base of the formation was placed at 

a dark crystalline dolomite, on the weathered surfaces 

of which may be seen thin discontinuous laminae of 

brown sandy material. The bed is strikingly laminated, a feature which is characteristic of the whole 

formation. Below this horizon there are a few darkgray dolomites, and above it there are a few light-gray 

dolomites similar to those characteristic of the Sevy 

dolomite. The contact between the two formations is 

merely a change in the proportions of light and dark 

gray dolomites and does not indicate any time break. 

The typical rock of the Simonson is a dark to medium 

gray dolomite in which the individual grains are large 

enough to be distinguished by the unaided eye. Individual beds are from 1 to 2 feet thick. The most 

striking feature is the very general presence of a fine 

lamination, caused chiefly by variations in the amount 

of darker pigment present in the laminae and to a much 

less degree by variations in the grain size. The laminae 

are in general extremely irregular in detail, much of 

this irregularity being clearly the result of original 

variations in deposition. Locally the irregularities are 

even more pronounced (pI. 5, E), and these are thought 

to have been caused by subsurface solution and subsequent slumping during the time the formation was 

being deposited. 

The following section of the formation was measured 

on the north side of Sevy Canyon and is typical of the 

formation in the area. 

Section of Simonson dolomite on north side of Sevy Canyon 

Dolomite conglomerate (base of Guilmette formation). 

Simonson dolomite: Fee! 

Medium- and dark-gray laminated dolomite, in beds 

1 to 2 feet thick, locally coarsely crystalline____ __ _ 329 

Light-gray sandy laminated dolomite; includes two 

thin layers of dark-gray dolomite and a 3-foot bed 

of dolomite conglomerate 75 feet above the base_ 96 

Dark-gray laminated dolomite___________________ 56 

Medium- and light-gray sandy dolomite_ _ _ _ _ _ _ _ _ _ 52 

Dolomite conglomerate_ 6 

Covered; probably largely laminated dolomite_ __ _ 170 

Medium- and dark-gray laminated dolomite with a 

few thin light-gray beds near base; at base dark 

dolomite 3 feet thick containing thin laminae of 

brown sandstone_ __ _ 254 

Light-gray dolomite of Sevy dolomite. 

963 

The two dolomite conglomerates in the above section 

apparently have little significance, as they cannot be 

found everywhere in the area. A similar conglomerate 

which is continuous, however, has been used to designate the base of the next higher formation. Its continuity is proved by the fact that it is found at the same 

distance below a distinctive fossiliferous bed throughout the area. Above this eon glomerate the lithology is 

distinctly different from that of the Simonson dolomite, 

although the fossil evidence indicates that but little 

time difference is represented. 
20 GOLD HILL MINING DISTRICT, UTAH 

Thickness.-In addition to the measurement obtained in Sevy Canyon, a second measurement was 

made on the north side of Kelly Canyon, where the 

thickness was found to be 1,030 feet. The difference 

of 70 feet between the two probably represents errors in 

measurement due to poor exposures and minor faulting rather than to original variations of deposition. 

Age and correlation.-Fossils are not abundant in the 

Simonson 

matopora-like 

dolomite, 

corals. 

except 

These 

for 

are usually 

small spherical 

not more 

Strothan 

an inch in diameter and are found in large numbers in 

certain b3ds. Three small lots were collected, upon 

which Mr. Kirk reports as follows: 

Three-quarters mile north-northwest of South Peak, on north 

side of Sevy Canyon: 

Favosites (digitate form). 

Bel1erophon sp. 

Stringocephalus burtoni Defrance. 

Martinia cr. M. meristoides Meek. 

Atrypa reticularis Linnaeus. 

M4C. North side of Simonson Canyon near mouth: 


Atrypa reticularis Linnaeus. 


TN-26 21. Half a mile north of Dewey prospect, on north 

side of Sevy Canyon: 

Favosites (digitate form). 

The formation is probably correlative with the Nevada limestone of the Eureka district in part. The horizon, by virtne of 

the Stringocephalus, may aecurately be placed as high as 

Middle Devonian. 

GUIL~fETTE FORMATION (MII>])Ll<~ ])lcVONIAN) 

Distribution.-The Guilmette formation, named 

after Guilmette Gulch, on the west side of the Deep 

Creek Mountains, forms the westernmost exposures of 

the range from Simonson Canyon northward to Sheridan Gulch, except for a few small areas occupied by the 

younger Woodman formation. The best exposure of 

the formation is on the north side of Sevy Canyon. 

The area covered by the formation is not continuous, 

being interrupted by three large transverse faults; and 

in the north it is further affected by warping and minor 

folding. In addition several small areas along the 

Lincoln Highway in the pass between the Deep Creek 

Mountains and Ochre Mountain are underlain by 

crumpled and crushed beds similar to those of the 

Guilmette. Another exposure that is thought to 

belong to this formation occurs on the north side of 

North Pass Canyon about half a mile east of the 

junction of the road from Bagley Gulch with the main 

road up the canyon. On the east edge of the quadrangle near the southern boundary there are outcrops 

of highly brecciated rock similar to this formation in 

lithology and, in some places, in fossil content. Some 

scattered outcrops on the north side of Dutch 

Mountain are also believed to belong in the Guilmette 

formation. 

Lithology.-The Guilmette fonnation is composed 

chiefly of dolomite but contains also some thick limestone beds and several lenticular sandstones. The 

dolomites for the most part differ in character from 

those found in the Simonson dolomite, although a few 

laminated beds are present near the bottom of the 

formation. The most abundant variety is a finegrained dolomite, dark to medium gray on fresh 

fracture and weathering to lighter shades of gray, that 

contains numerous vugs almost completely filled with 

white coarsely crystalline dolomite. Less abundant 

but far more striking in character is a dark dolomite 

filled with fragments of tubular corals. Most of these 

beds contain a coral of small diameter (Oladopora sp.), 

but some are filled with a larger, branching variety 

(Striatopora sp.). So far as known these coralline beds 

are limited to this formation. 

The limestones are different from any found lower 

in the section. They are massively bedded, dense 

rocks that are light brownish gray on fresh fracture 

but weather to shades of bluish gray. The weathered 

surface is characteristically splotched with a tan discoloration. Fossils have not been found in such beds. 

The sandstone beds form a comparatively small portion of the formation, but the brownish color they 

assume on weathering makes them conspicuous. They 

are fine-grained and are thoroughly cemented by dolomite or calcite. 

The following section, measured on the north side 

of Sevy Canyon, illustrates the interbedding of the 

various lithologic types: 

Section of Guilmette formation on the north side of Sevy Canyon 

Sandstone and limestone of Woodman formation. 


Guilmette formation: Fet! 


1. 	 Limestone, massively bedded; weathers to a light 

bluish gray splotched with tan_ __ _ _ _ _ _ _ _ _ _ _ _ 20 

2. Dolomite, dark gray, coralline _ _ _____ . . 2 

3. Limestone, like no. L._______________________ _ 10 

4. Sandstone, light gray on fresh fracture; weathers brown_____ _______ _ _____________________ 15 

5. Limestone, like no. L ____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 30 

6. 	 Dolomite, dark and medium gray, fine-grained; 

contains numerous vugs almost completely filled 

with white coarsely crystalline dolomite_ _ _ _ _ _ _ _ 31 

7. Sandstone, like no. 4__________________ ________ 6 

8. Dolomite, like no. 6; includes a few thin layers like no. 2_ _ _ _ _ _ _ __________________ _____ 46 

9. Dolomite, dark gray, filled with Striatopora___ _ _ 3 

10. Dolomite, like no. 6 ________________________ . 25 

11. Dolomite, like no. 9________________ _ _ ___ _ 6 

12. Dolomite, like no. 6_ _ _ _ _ _ _ _ _ _ 28 

13. Sandstone, like no. 4_______ _ ___ ___ _ ___ _ 6 

14. Dolomite, like no. 6__ ___ __ _____ ___ _ _ _ _ _ 14 

15. Sandstone; weathers brown, dolomitic___________ 3 

16. Sandy dolomite, medium gray; poorlyexposed____ 29 

17. Dolomite, dark and medium gray, mottled; a few 

vugs filled with white coarsely crystalline dolomite; poorly exposed___ _ _ __ __ ___ _ _ _ _ __ _ _ _ _ 34 

18. Limestone, like no. L __________ •__ .• _ ______ 10 

19. Limestone, thinner-bedded, including a few thin layers of dark-gray dolomite____________ _____ _ 26 

20. 	 Limestone, light gray, mottled with dark-gray dolomite splotches ___ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 27 
DEVONIAN 

Section of Guilmette formation on the north side of Sevy CanyonContinued 

Feet 

21. Dolomite, 	dark gray; includes lighter-gray dolomite conglomerate_____ . __ ___ _ ________ _ 21 

22. Dolomite, medium gray, finely laminated________ _ 26 

23. Dolomite, like no. 17 __ 6 

24. Limestone, like no. L _____ _ 10 

25. Dolomite, like no. 17__ _ ______ _ _ 63 

26. Dolomite, bleached and brecciated________ _ 60 

27. Limestone, like no. 1, poorly exposed _______ _ 78 

28. Dolomite, like no. 17 ____________ _ 32 _________ 9 29. Limestone, like no. L ____________ _ 

30. Limestone, dolomitic; poorlyexposed__ 22 

31. Dolomite, like no. 22_ 	 3 

32. Limestone, like no. 1; poorly exposed __ _ 9 

33. Sandstone, like no. 4_____ _____________ _ _ 14 

34. Dolomite, like no. 22 _ _ _ _ _ _ _ __________ _ 58 

35. Dolomite, medium gray, full of seetions of Stringocephalus burtoni. _ _ __ _ _ __ _ _ ________ _ 4 

36. Dolomite, like no. 17, 	with thin zone like no. 9, 30 

feet above base__ _____________ __________ 78 

37. Dolomite conglomerate_____ 	 24 

Laminated dolomite of Simonson dolomite. 

888 

The upper contact of the formation is well exposed 

on the north side of Sevy Canyon, where a thin bed of 

bluish-gray limestone containing abundant Carboniferous fossils overlies massive unfossiliferous limestone 

similar to those found throughout the Guilmette formation. No angular discordance or clastic beds were 

distinguished at the contact. 

Thickness.-Three measurements of the thickness of 

the formation were made. One on the north side of 

Simonson Canyon showed 1,400 feet and did not include the uppermost beds. A second, on the south 

side of Sevy Canyon, showed 1,200 feet; and a third, 

given in detail in the preceding section, 888 feet: All 

three of the sections measured are cut by numerous 

small faults. Allowance was made for the displacements caused by many of these faults, but it is not 

improbable that some escaped detection. The greater 

part of the variation in thickness, however, is due to 

an unconformity at the top of the formation. 

Age and correlation.-Fossil collections were made 

at different horizons in the formation. Edwin Kirk, 

who participated in the collecting, reports on them as 

follows: 

TN-26 25. One mile east of southeast corner of sec. 13, T' 

9 S., R. 19 W.: 

Stringoeephalu8 burtoni Defrance. 

TN-26 38. Three-fourths of a mile north-northwest of South 

Peak: 

Stringocephalus burtoni Defrance. 

Atrypa retieularis Linnaeus. 

M~5. South side of Sevy Canyon: 

Stringocephalus burtoni Defrance. 

These three lots came from beds equivalent to no. 

35 in the section above. The two following lots are 

somewhat.higher. 

r 

SYSTEM 	 21 

M-4B. North side of Simonson Canyon, about 2 miles southeast of Simonson ranch: 

Favosites (digitate form). 

Syringopora sp. 

Atrypa reticularis Linnaeus. 

M-6. 	South side of Sevy Canyon: 

Atrypa reticularis Linnaeus. 

Martinia meristoides Meek. 

The next two lots were obtained from limestone 

beds near the top of the formation. 

TN-26 31. About 1 mile southwest of hill 6634, on west side 

of Ochre Mountain: 

Pycinodesma? sp. 

North side of Sevy Canyon: 

Platyschisma? cf. P. mccoyi Walcott. 

Cyclonema? sp. 

Pycinodesma? sp. 

Mr. Kirk further reports: 

In the formation occur large numbers of Cladopora sp., which 

has a very widespread distribution throughout the Western 

States, being found in the Jefferson limestone of Montana and 

ranging south into Nevada. It is readily recognized by its 

small size, seldom being over 2 millimeters in diameter. Associated with this is a branehing coral probably referable to 

Striatopora, which often forms a network on some of the surfaces. Occasional heads of "Stromatopora", ranging in size 

up to 3 or 4 inches in diameter, are found. 

The formation is probably correlative with the Nevada limestone of the Eureka district in part. The horizon by virtue 

of the Stringocephalu8 may accurately be placed as high as 

Middle Devonian. 

UNCONFORMITY AT BABE OF CARBONIFEROUS 

The only exposures of the contact between the 

Mississippian and the Devonian that are not complicated by faulting are north and south of Sevy 

Canyon. There is little physical evidence in either of 

these places for the presence of an unconformity. 

Three bits of indirect evidence, however, indicate that 

there is a marked unconformity at this horizon. The 

first is the variation in thickness of the Devonian 

Guilmette formation from 1,400 feet to 890 feet \vithin 

a distance of about 3 miles. Second, in the Deep 

Creek Mountains upper Mississippian rocks belonging 

to the Woodman formation overlie the Devonian 

directly, but on Dutch Mountain several hundred feet 

of the lower Mississippian Madison limestone is found 

beneath beds of the Woodman formation that are 

equivalent to those immediately above the Devonian 

to the south. The third bit of evidence is the absence 

of upper Devonian sediments at Gold Hill. Beds of 

this age are found at Pioche, Nev.,53 and in the San 

Francisco district, Utah/4 to the south; in the Eureka 

district, Nev.,5s to the west; in the Tintic district, 

13 Westgate, L. G.• Geology and ore deposits of the Pioche district, Nev.: U.S. 

GeoL Survey Prof. Paper 171. PP. 16-19. 1932. 

"Butler. B. S., Geology and ore deposits of the San Francisco district, Utah: 

U. B. GeaL Survey Prof. Paper 80, pp. 34-35, 1913. 

" Hague, Arnold, Geology of the Eureka district, Nev.: U.S. Gool. Survey Mon. 

20, pp. 81-M, l8lJ2. 
22 GOLD HILL MINING DISTRICT, UTAH 

Utah/6 to the east; and in the Randolph quadrangle, 

Utah,s7 to the northeast. 

Loughlin 1'8 has summarized evidence for an unconformity between the Devonian and Mississippian for 

several places in central Utah. Since Loughlin wrote 

his report Calkins 59 has noted a break at this horizon 

in the Cottonwood district, and Gilluly 60 found one 

in the Oquirrh Range. At the last-named locality 

Madison limestone overlies Devonian (?). This, combined with the several unconformities found at Gold 

Hill, suggests that the unconformity is somewhat less 

significant than was thought by Loughlin, and that 

the break he observed at various places in central 

Utah is a summation of several periods of erosion, 

of which the pre-Mississippian period was perhaps the 

longest. 

ORIGIN OF THE PRE-CARBONIFEROUS DOLOMITIC 


FORMATIONS 


The method of formation of dolomite and dolomitic 

limestones has been a matter of debate for a number 

of years. The evidence afforded by the thick dolomite 

formations in the Gold Hill quadrangle is thought to 

be of sufficient scientific interest to warrant presentation at this place. 

The theories of origin that have been advanced are 

numerous, but the causes assigned may be classed 

under three general headings-(1) primary deposition, 

the dolomite having been laid down either as a chemical 

or organic precipitate, or as a clastic deposit; (2) alteration, an original limestone deposit having been altered 

to dolomite either before or after its elevation above 

sea level; (3) leaching, magnesium carbonate having 

been concentrated in a deposit that originally contained 

only a small amount of it by the removal of calcium 

carbonate in solution, either above. or below sea level.61 

At the present time the view most generally held is 

that dolomite is formed by the alteration of an original 

limestone deposit before it is elevated above the sea. 

Dolomites formed by two different methods have 

been described in the sections on the Abercrombie 

formation and the Sevy dolomite-those in the Abercrombie formation, as a result of alteration along 

fractures after elevation above sea level; and the dolomite matrix in the conglomerates near the base of the 

Sevy dolomite, as a result of clastic deposition. The 

remainder and great bulk of the dolomite in the Gold 

Hill quadrangle is thought to have been formed by the 

U Loughlin, G. F., Geology and ore deposits of the Tintic mining district, Utah: 

U.S. Geol. Survey Prof. Paper 107, p. 36, 1919. 

67 Richardson, G. B., The Paleozoic section in northern Utah: Am. Jour. Sci., 

4th ser., vol. 36, pp. 411-412, 1913. 

U Loughlin, G. F., op. cit., pp. 3&-38. 

4' Calkins, F. C., Ore deposits of Ctah: U.S. Geol. Survey Prof. Paper 111, pp. 

237-238. 1919. 

,. GlIluly, James, Geology and ore deposits orthe Stockton and Fairfield quadran. 

gles, Utah: U.S. Geol. Survey Prof. Paper 173, p. 22, 1932. 

61 The evidence in favor of and opposed to the various theories, together with a 

historical summary, may be found in either Steidtmann, Edward, The evolution of 

limestone and dolomite: Jour. Geology, vol. 19, pp. 323-345, 392-428, 1911; or Van 

Tuy!, F. M., The origin of dolomite: Iowa Geol. Survey, vol. 25, pp. 251-421, 11116. 

alteration of an original limestone deposit before the 

rock was elevated above sea level. Furthermore, it is 

thought that most, if not all, of the alteration occurred 

very shortly after the deposition of the limestone, 

for the most part in shallow water, and probably at 

times of little or no deposition. Raymond 62 and 

Twenhofel 63 have recently noted briefly the possible 

importance of the last-named factor. The writer considers it to have been probably the most important 

one in the formation of the dolomites exposed at 

Gold Hill. 

The evidence indieating that dolomitization was 

accomplished by the alteration olan original limestone 

before it was elevated above sea level is similar to that 

which has been advanced by many investigators and 

need not be repeated here. The coincidence of dolomitization with texture and struc.ture characteristic of 

shallow water has been pointed out by several writers 64 

in recent years. Such features occur throughout the 

dolomitic formations at Gold Hill and are illustrated 

in plate 5, 0, D, E. They include cross-bedding, oolites 

and pisolites, intraformational conglomerates, local unconformities, and lenticular beds. It is perhaps significant that many of the beds not possessing these 

features are mottled dolomites, in which the mottling 

is due to areas of less complete dolomitization. Near 

many of these mottled dolomites beds of relatively 

pure limestone are found. 

The evidenee for the theory that dolomitization is 

related to periods of nondeposition on the sea bottom 

is less direct. I t is based largely on the following 

reasoning: A thick section of sediments that shows 

shallow-water phenomena throughout implies continual sinking of the sea floor. This sinking must have 

progressed at the same rate as the deposition of sediment, or more slowly; otherwise the higher beds would 

show characteristics of deeper water. Sinking at the 

same rate as deposition would almost certainly imply 

a dependence of sinking upon sedimentation, which 

Barrell 65 has shown is not warranted by t.he evidence 

afforded by the deltas of the Nile and other great 

rivers. But if the rate of sinking is slower than the 

rate of deposition, there must,' of necessity, be many 

periods during which there is no deposition of sediment, 

and any material deposited will be above the baselevel 

of wave or current action and will be swept away to 

regions that are below wave base. Calcareous muds 

will thus be subject to reworking and alteration by 

the sea water for some time, and it is thought that in 

this fact is the chief explanation of dolomitization. 

The analyses assembled by Steidtmann show that 

"Raymond, P. E., A possible factor in the formation of dolomlte: Goo!. Soo.' 

America Bull., vol. 36, p. 168, 1925. 

"'I'wenhofel, W. R., A treatise on sedimentation, p. 262, Baltimore, 1926. 

"Skeats, E. W., The formation of dolomite: Am. Jour. Sci., 4th ser., vol. 45, pp. 

194-199, 1918. Van Tuyl, F. M., The depth of dolomitization: Science, new ser., 

vol. 48, pp. 35&-352, 1918. Tarr, W. A., A possible factor in the origin of dolomite: 

Science, new ser., vol. 51, p. 521, 1920. 

.. Barrell, Joseph, The strength of the earth's crust: Jour. 'Geology, vol. 22, 

pp. 36-48, 1914. 
CARBONIFEROUS SYSTEM 23 

almost all limestones contain a small amount of magnesium carbonate, which might be interpreted as a 

measure of the amount of replacement or alteration 

that occurs during continuous sedimentation. A prolonged exposure of the same calcareous mud to wave 

and current action would also permit selective leaching 

of calcium carbonate by sea water, a phenomenon 

which is known to occur in nature.56 

The hypothesis outlined in the preceding paragraph 

seems to explain most of the characteristics of the 

dolomitic formations in the Gold Hill quadrangle. 

Beds showing shallow-water texture, wherever more 

than a few feet thick, are very thoroughly dolomitized, 

yielding no effervescence whatever with dilute acid. 

Dolomitic beds without this texture are mottled by 

patches higher in calcium carbonate and are in many 

places interbedded with limestone. It is thought that 

these represent periods when sedimentation was slightly slower than down warping , or in which downwarping 

was somewhat spasmodic, allowing rather thick beds 

to be deposited before baselevel was reached, and then 

sinking was again initiated before dolomitization was 

complete. 

Similar dolomitic rocks at Tintic have been explained 

by Loughlin 67 as the result of alteration of porous 

sediment in shallow water continuing for long periods 

after deposition but inhibited at certain times and 

places by the deposition of impervious argillaceous 

sediment or limestone mud. This explanation implies 

conditions similar to those inferred by the writer but 

is too restricted to be applicable at Gold Hill, because 

of the many places in which coarsely crystalline limestone and dolomite are in contact without intervening 

shaly material or dense limestone, as in the Trippe 

limestone and the Guilmette formation. Shaly material is, however, far more' abundant in limestone zones 

than elsewhere, but it is thought that this is due 

rather to more rapid sedimentation in areas that had 

not yet reached the baselevel of deposition. Blackwelder 68 has considered the formation of the Bighorn 

dolomite in Wyoming the result of an abundance of 

magnesia-rich algae. There is no evidence at Gold 

Hill that algae have exerted any influence in the formation of dolomite. Daly 69 has suggested that many 

of the pre-Cambrian and early Paleozoic dolomites 

in the Rocky Mountain region at the international 

boundary are the result of direct precipitation. The 

evidence that has been presented in the foregoing 

descriptions is opposed to such an origin at Gold Hill, 

and it is not believed to be of any quantitative importance there. 

.. Cl!ll'ke, F. W., The data of geochemistry, 5th ed.: U.S. Geol. Survey Bull. 770, 

p. 574, 1924. 

61 Loughlin, G. F., Geology and ore deposits of the Tintic mining district, Utah: 

U.S. Geol. Survey Prof. Paper 107, pp. 91-93, 1919. 6. Blackwelder, Eliot, Origin of the Bighorn dolomite of Wyoming: Geol. Soc. 

America Bull., .vol. 24, pp. 607, 624, 1913. 

fi~ Daly, R. A., First calcareous fossils and the evolution of the limestones: Geol. 

Soc. America Bull •• vol. 20, pp. 153-170, 1009. 

Itis not at all probable that the theory that has been 

outlined here will be everywhere applicable, for the 

many diverse hypotheses that have been put forward 

indicate that the conditions of dolomitization differ 

in different places. Furthermore, it may be that the 

basic cause of dolomitization has not yet been determined and that the many theories of origin simply 

reflect the various environmental conditions in which 

this unknown cause is effective. 

CORRELATION OF PRE-CARBONIFEROUS SEDIMENTARY 

ROCKS IN EASTERN NEVADA AND WESTERN UTAH 

The correlations made for the pre-Carboniferous 

formations are given in tabular form in figures 3 and 4. 

Many of the correlations are extremely tentative, be­

~ause of the common paucity of fossils and the notable 

variations in lithology in nearby areas ..These figures 

bring out rather clearly the several unconformities 

present and, to a less extent, the variations in the kind 

of sediment deposited. The latter feature is somewhat 

masked by the failure of some of the earlier reports 

to differentiate dolomite and limestone. 

Of chief interest, however, are the striking differences between the north-south and east-west sections. 

In the former the thicknesses of formations of the same 

age are roughly equivalent, and except for the absence 

of Middle Ordovician and Upper Devonian at Gold 

Hill, the time and extent of intersystemic and intrasystemic erosion are shown to have been nearly the 

same in all sections. In the east-west sections, however, there is an abrupt thickening of all formations 

from east to west and also a different succession.10 

CARBONIFEROUS SYSTEM 

Rocks of Carboniferous age are by far the most 

widespread of the Paleozoic sedimentary rocks in the 

quadrangle. They have been divided into 6 formations-3 Mississippian, 2 Pennsylvanian, and 1 

Permian. Three facies of the Carboniferous have been 

distinguished and designated the eastern, central, and 

western facies. They have been brought into more or 

less close contact with one another by two large thrust 

faults, although originally they were probably several 

miles apart. The eastern facies is represented by 

rather scanty outcrops of only one formation, the 

Woodman, which overlies the older Paleozoic rocks 

'with slight unconformity and is overridden by' the 

lower of the two thrusts. The central facies, which 

includes the Ochre Mountain limestone and the 

Manning Canyon and Oquirrh formations, lies between 

the two thrusts. The western facies, which contains 

representatives of all six formations, lies above the 

upper thrust. The lithologic differences between the 

Manning Canyon and Oquirrh formations in both the 

10 Nolan, T. B., A late Paleozoic positive area in Nevada.: Am. Jour.·Scl., 5thser., 

vol. 16, pp. 1M-161, 1928. 
24 GOLD HILL MINING DISTRICT, UTAH 

western and central facies are striking. The relations 

between the three facies are summarized by figure 5. 

MADISON LIMESTONE (LOWER MISSISSIPPIAN) 

Distribution.-The Madison limestone is found only 

on Dutch Mountain. Outcrops occur on all sides of 

the mountain at altitudes between 6,000 and 7,000 

feet. On the south and east sides this limestone forms 

Eureka district, 


Nevada (Hague) 


and two smaller ones are in Accident Canyon and near 

the head of Trail Gulch. There are two small outcrops on the north side of Dutch Mountain, one 

near the mouth of Accident Canyon and one near 

the summit of the hill above the Garrison Monster 

mine. 

The small area of limestone near the town of Clifton 

contains a few poorly preserved fossils, which, accordNevada 

limestone 

Simonson 

dolomite 

Upper

t-:5~e~vy~d",-ol'.':om~~ite:!-l~~~~-;;~:l\YJ~~~~~Devonian Mississippian 

Pogonip 

limestone 

shale 

Secret Canyon 

shale 

Up~er Cam dan Lamb 

dolomite 

Trippe 

limestone 

Young Peak dolomite 

Middle 

Cambri~n 

Middle 

evonlan Oquirrh Range, 

Utah (Gilluly) 

Lower 

Cambrian 

. Bowman limestone 

Hartmann 

limestone 

o hir formation? 

Cottonwood quadrangle, 

Utah (Calkin 5) 

Lower 

Cambrian" /' 

./

,/ Pre.... 

Cambrian 

Limestone 

Shale 

Quartzite 

Middle 

Eldorado Cambrian 

limestone 

Mountain 

Prospect -?

quartzite Lower 

Cambrian 

Abercrombie 

formation Tintic 

quartzite 

Busby quartzite? 

Cabin shale Lower 

Cambrian 

Prospeot 

Mountain 

quartzite 

FIGURE 3.-Correlation of pre-Carboniferous rocks in eastern Nevada and western Utah Cram west to east 

a fairly continuous belt, broken by two large faults, 

one in Tribune Gulch and one south of the Spotted 

Fawn mine. On the northwest and west sides the 

formation is found only in the bottoms of valleys, 

where it ~ exposed in inliers, eroded through younger 

rocks. The largest of these outcrops is in Royal Gulch, 

ing to G. H. Girty, somewhat resemble those found in 

the Madison limestone. Lithologically, however, the 

beds resemble the Ochre Mountain limestone, and this 

apparent relationship is heightened by the presence of 

an interbedded belt of black shale, apparently the 

Herat shale member of the Ochre Mountain. The 
-----------

CARBONIFEROUS SYSTEM 25 

outcrop has therefore been mapped as the Ochre 

Mountain limestone. 

All the outcrops of the Madison belong to the 

western facies of the Carboniferous. No beds of this 

age are found in the eastern facies, in which upper 

Mississippian rocks rest directly upon the Devonian. 

Itis not known whether the formation is present in the 

central facies, as the oldest beds of this group exposed 

within the quadrangle belong to the Ochre Mountain 

limestone, of upper Mississippian age. 

Pioche district, 


Nevada(Westgate) 


MissisSlpplan
 w~st Range
 limestone 
 Upper Devonian 

Silverhorn Middle 

Devonian dolomite 

Ely Springs 1\ Dolomite dolomite 


EureKa gt::ian:zi e 


[rank Hill limestone 
 Middle and 

L ~E?liow Lower Ordovician 

Middle 

Devonian 

Silurian 

Upper OrdoVician 

House Range, 

Utah (Walcott) Lower 

Ordovician 

Notch Peak 

Mendha Upper limestone Upper limestone Cambrian Cambrian 

?-

Orrformation 

High land Peak 

limestone Middle Weeks 

limestone 

Cambrian Middle 

Chisholm 

limestone 

Marjum Cambrian 

limestone ~nd;~~::ton'~ _Wheel,er formation formation 

Swasey formation 

Prospect Dom e Canyon Is. 

. Mountain Howell formation 

quartzite Lower _an >is or r-i"'lo·cne 1" Cambrian Prospect Lower 

Mountain 

quartzite Cambrian 

Vertical scale 

2,000 0 4,~OO Feet ! I J I I I If! !! I 

stone is a dull dark-gray on fresh fracture and weathers 

to a distinctly lighter-gray. It is normally very dense 

but includes a great number of crinoid stems made up 

of coarsely crystalline calcite. 

In the greater part of the formation as exposed the 

beds are moderately thin, ranging from 3 inches to 

1 foot in thickness. The bedding is marked in many 

places by a concentration of pink or less commonly 

yellowish clay. Small amounts of similarly colored 

clay are also found within individual beds in some 

Gold Hill quadrangle, 

Utah (Nolan) 

Guilmette 

formation 

Simonson 

dolomite 

Sevy dolomite 

Laketown 

dolomite 

F!5 h Haviln dQIo mit." 

Chokecherry 

dolomite 

Hicks 

formation 

Lamb 

dolomite 

Trippe 

limestone 

Young Peak 

dolomite 

Abercrombie 

formation 

I 

Busby quartzite 


Cabin shale 


MisSissilJDian 

UPP~ eVor)lar) 

Middle Devonian 

'e-t' SiWf'\ 

oroo'/Iciafl er \J Middle 

and

!Lo~er Lower 

Ordovician Ordovician 

Upper 

Cambrian 

I? 

Middle 

Cambrian 

,/ 

? 

Lower 

Cambrian 

Randol~h quadranf'e, 

Utah ( ichardson 

IJnreeforks limestone 

Jefferson 

dolomite 

Laketown 

dolomite ! 

Fish Haven 

dolomite 

t>)'Yan Peak _quartzite' 


Garden City 


limestone 


St,Charles 

limestone 

Nounan 

limestone 

Bloomington 

formation 

Blacksmith 


limestone 


Ute limestone 


Langston limestone 


Brigham 


quartzite 


Prospect 

Mountain 

quartzite 

FIGURE 4.-0orrelation of pre-Oarboniferous rooks in eastern Nevada and western Utah from north to south. 

The name is taken from the Madison Range, in 

south-central Montana, where rocks of this age were 

described by Peale. 

Lithology.-The Madison limestone is best exposed 

on the north side of Pool Canyon, where, in places 

distant from the quartz monzonite, it forms cliffy 

slopes beneath less resistant sandstones. The lime35311-35--3 

places, and the weathered surfaces of such beds have 

a faint pinkish mottling. 

Many beds are crowded with crinoid stems and 

small cup corals. In a few places these fossils are 

partly silicified and weather out in relief from the 

usual smooth surface. Fossils other than the two kinds 

mentioned are not easily found. This is probably due 

----....----....~~~-

I 
26 GOLD HILL MINING DISTRICT, UTAH 

to the rather general fracturing to which the formation has been subjected and which has resulted in 

an abundance of veinlets and splotches of white 

calcite. 

At the top of the formation there are about 10 or 

15 feet of more massively bedded limestone, which 

contains numerous nodules of dark chert, some as 

much as a foot in largest diameter. Above these beds, 

apparently conformable, are sandstones of the Woodman formation. 

'Nestern facies 


Triassic 


Oquirrh 

formation 

Limestone 

member 

Same thickness in 

both facies assumed 

Herat shale '1E~mlbel~-~~~~~. rr 

Vertical scale 

Woodman 

formation 

Central facies 

ili~Horizon of black chert. 

The faunas are not very extensive, and the specimens are very 

poorly preserved, but there can be little doubt of the geologic age 

as lower Carboniferous and the correlation as with the Madison 

limestone. 

6052 and 6329. North side of Tribune Gulch on ridge line: 

Zaphrentis sp. 


Amplexus aff. A. fragilis. 


Syringopora surcularia. 


TriplophylJum excavatum. 


Lithostrotion sp. 


Chonetes loganensis. 


Top of exposure; 

probably limited 

above by thrust 

fault 

Bottom of exposure; 

probably limited below 

by thrust fault 

1,000 0 5,000 Feet I t I It I I 

FIGURE 5.-Relations between the three facies of the Carboniferous rocks. 

Spirifer centronatus. 


Straparollus ophirensis. 


Euomphalus utahensis. 


Euomphalus luxus? 


Nautilus? sp. 


Phillipsia peroccidens. 


Eastern 


facies 


Top of exposure; 

probably limited 

above by thrust fault 

~~~---=9 {INCONFORMITY 

Thickne88.-The maximum thickness of the Madison 

limestone was found in Pool Canyon, where it is about 

400 feet. Here, however, as elsewhere on Dutch 

Mountain, the lower contact is a thrust fault, and as 

a result the observed thickness varies considerably. 

In the Deep Creek Mountains the formation was not 

found, the next higher (Woodman) formation resting 

directly upon the Guilmette formation. 

Age and correlation.-Fossils from the Madison limestone were examined by G. H. Girty, who says: 

6323. North side of Royal Gulch 2,000 feet southeast of 

cabin: 

Triplophyllum sp. Composita sp. 

Syringopora 8urcularia? Euomphalus utahensis? 

Spirifer centronatus? IPlatyceras sp. 

Two collections from this formation were made by 

L. D. Burling during a reconnaissance trip through 

Utah and Nevada in August 1905. Lists of these 

have not previously been published and are therefore 

included here. 
CARBONIFEROUS SYSTEM 27 

98. North side of Pool Canyon, southeast side of Dutch 

Mountain, about 1% miles up the canyon and 200 to 300 feet 

above the canyon bottom: 

Syringopora? sp. IEuomphalus sp. 

Triplophyllum sp. Platyceras sp. 

This collection was made about 150 feet below the top of the 

formation. 

99. North side of Pool Call YOI! , southeast side of Dutch 

Mountain [label incomplete]: 

Productus galeanus'? 

Triplophyllum sp. 

Cladochonus sp. 

Dielasma? sp. 

Crinoid columnals. Spirifer afT. S. grimesi. 

Spirorbis sp. Spirifer afT. S. vernonel1sis. 


Fenestella, several sp. 
 Spiriferina subelliptica? 


Pinnatopora sp. 
 Spiriferina solidirostris? 


Cystodictya sp. 
 Reticularia cooperensis. 


Schiz;ophoria? sp. 
 Cleiothyridina sp. 


Pustula sp. 


This collection was made at the top of the formation near the 

contact with the Woodman formation. 

Mr. Girty states that "both lots appear to be 

Madison." 

The Madison limestone in the Oquirrh Range 71 is 

of lower Mississippian age, as are the Victoria quartzite, the Gardner dolomite, and the lower portion of the 

Pine Canyon limestone in the Tintic district. 72 

WOODMAN l<'OltMATION (UPPElt MISSI8!<IIPPlAN) 

Distribution.-The Woodman formation, named 

from Woodman Peak, on the south side of Dutch 

Mountain, is exposed at several places within the 

quadrangle. In the Deep Creek Mountains there are 

four outcrops north and south of Sevy Canyon. 

These belong to the eastern facies; the remaining 

areas belong to the western facies. Beds higher in 

the formation are present on the west and south sides 

of Ochre Mountain. The most extensive exposures of 

the formation, however, are found on Dutch Mountain, particularly on the higher parts of the western 

slope. Smaller exposures occur in several places along 

the north side of Dutch Mountain. 

There are two other areas in which the Woodman 

formation may be present. One of these is the large 

block of sedimentary rocks surrounded by quartz 

monzonite north of Clifton. A small collection of 

poorly preserved fossils from this locality was regarded 

by Mr. Girty as resembling the Woodman fauna more 

closely than any other. Lithologically, however, the 

beds resemble those of the overlying Ochre Mountain 

limestone, and because of their association with a 

black shale, thought to be the Herat shale member, 

they have been mapped as the higher formation. The 

other region for which some doubt exists is at the 

6 267-foot hill on the south side of North Pass Canyon. 

Two poor fossil collections were made here. The 

11 GlIluly, James, Geology and ore deposits of the Stookton and Fairfield quad· 

rangles, Utah: U.S. Geol. Survey Prof. Paper 173, pp. 23-25, 1932. 

" Loughlin, G. F., Geology and ore deposits of the Tintic mining district, Utah: 

U.S. Geol. Survey Prof. Paper 107, pp. 38-41, 1919. 

lower one was referred somewhat doubtfully to the 

Woodman formation, and the upper one \vith similar 

reservations to the Ochre Mountain limestone. However on the north side of the canyon similar beds 

that' are apparently continuous with these are definitely of Pennsylvanian age, and the beds in question 

have therefore been mapped as a part of the Oquirrh 

formation. 

Lithology.~-The Woodman formation consists of a 

lower division of dominant calcareous sandstone and 

an upper division consisting chiefly of sandy limestone. 

These two units are found in both the eastern facies 

and the western facies. 

The sandstone portion at the base is roughly 200 

feet thick. The beds are purplish or reddish brown, 

are fine-grained, and contain a variable though small 

proportion of calcium carbonate as cement. Locally 

nodules of black chert, an inch or so in maximum 

diameter are found in the sandstone. Several thin 

beds of s~ndy limestone, which are probably lenticular, 

and a minor amount of shale are usually present. 

This part of the formation is everywhere poorly exposed, as the sandstone breaks down into small rectangular blocks, which not only cover the surface 

underlain by the formation but form extensive areas 

of talus that conceal the adjoining formations. 

The upper and thicker calcareous division comprises rocks of several varieties. The most abundant 

is a sandy limestone which is dark gray to almost 

black on fresh fracture but which weathers light brown 

to pinkish. It leaves a large residue of sandy material 

when dissolved in hydrochloric acid. Most beds of 

this character contain nodules of dark-gray or black 

chert. These nodules are generally 6 inches or so in 

diameter but may be as much as 11 foot. They include 

casts of fossils in many places. There is, as a rule, no 

sharp boundary between the chert and .the limeston~, 

the contact being formed by alternate Irregular lamInations of dark chert and tan-weathering sandy limestone. Interbedded with the sandy limestones are 

calcareous sandstones. The boundary between the 

two kinds of rock is not sharp, and one passes into the 

other with increase or decrease in the amount of sand. 

The sandy limestones are much more abundant. 

Two other varieties of limestones may be noted. 

One is a platy fine-grained limestone which is dark-gray 

on fresh fracture and a very light gray on weathered 

surfaces. It contains only a small amount of insoluble 

material. The other variety is found locally in thin 

beds. It is a coarsely crystalline medium-gray limestone, crowded with fossils, chiefly large crinoid stems. 

The fossils are silicified in many outcrops of these beds. 

The following section of the formation was measured 

on the south side of Sevy Canyon, in the Deep Creek 

Mountains. It is incomplete, as the top of the formation is not exposed, but is the thickest of all the outcrops of the forma tion examined. 
28 GOLD HILL MINING 

Incomplete section of Woodman formation on south side of Sevy 


Canyon 
 Feel 

Thin-bedded sandy and cherty limestone _ _ _ _ _ 77 

Calcareous sandstone__ _ _ _ _ __ __ _ __ _ _ _ _ _ _ _ _ _ _ _ 59 

Thin-bedded blue-gray cherty limestone _ _ _ _ _ _ _ _ _ _ _ 76 

Thin-bedded sandy limestone_.. __ _ _ _ ________ 30 

Calcareous sandstone__ _ _ _ _ _ _ _ _ 46 

Thin-bedded sandy limestone_____________ 63 

Blue-gray massively bedded cherty limestone__ _ _ _ _ _ _ _ 15 

Thin-bedded sandy and cherty limestone______ 166 

Thin-bedded sandy limestone with some calcareous 

sandstone_____________________________ 137 

Thin-bedded sandy and cherty limestone_____ 62 

Thin-bedded sandy limestone___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 86 

Calcareous sandstone with a few beds of sandy limestone_ 209 

Limestone _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1 

Limestone of Guilmette formation. 

1,027 

Thickness.-The total thickness of the formation is 

. unknown, as nowhere in the quadrangle is a complete 

section exposed. The lower 1,000 feet is exposed on 

the Deep Creek Mountains, and the upper 700 or 800 

feet on Ochre Mountain. A varying thickness of the 

formation is shown on Dutch Mountain, but at every 

exposure there the upper beds have been eliminated by 

faulting at the contact with the overlying Ochre 

Mountain limestone. Although no satisfactory correlation could be made between the lower beds on Ochre 

Mountain and the upper beds in the Deep Creek 

Mountains, they are thought to indicate a total thickness for the formation of about 1,500 feet. There is 

no evidence to indicate any striking difference in 

thickness between the various facies. 

Age and correlation.-The Woodman formation is of 

upper Mississippian age. The overlying Ochre Moun­ i 

tain limestone is also of this age, and Mr. Girty reports 

that "the Woodman and Ochre Mountain faunas are 

not sharply distinguished in my mind; .or better, many 

of the collections are too small, or too poorly preserved, 

or too nondescript in character to be amenable to the 

distinctions that I do make." The formation may be 

correlated directly with the Deseret limestone and 

Humbug formation of the Oquirrh Range, 73 the Humbug formation of the Tintic district,74 and the lower 

portion of the widespread Brazer limestone,75 to the 

northeast. 

The fossil collections from the formation have been 

studied by Mr. Girty, whose determinations are as 

follows: 

Collections from the eastern facies 

6046. 2,200 feet east-southeast of southeast corner of sec. 

13, T. 9 S., R. 19 W.: 

" Gilluly, James, Geology and ore deposits of the Stockton and Fairfield quad· 

rangles, Utah: U.S. Geol. Survey Prof. Paper 173, pp. 25-29, 1932. 

,. Loughlin, G. F., Geology and ore deposits of the 'I'lntic mining district, Utah: 

U.S. Geoi. Survey Prof. Paper 107, pp. 41-42, 1919. 

1$ Mansfield, G. R., Geography, geology, and mineral resources of part of south· 

•astern Idaho: U.S. Geol. Survey Prof. Paper 152, pp. 63-71. 1927. 

DISTRICT, UTAH 

Fenestella sp. 

Productus aff. P. burlingtonensis. 

Productus ovatus. 

Pustula afr. P. alternata. 

Rhynchopora? sp. 

Coelonautilus? sp. 

6053 and 6324. North side of Sevy Canyon, 2,300 feet westsouthwest of point at 7,164 feet: 

Triplophyllum sp. 

Cladochonus sp. 

Crinoid? indet. 

Fenestella, several sp. 

Pinnatopora sp. 

Cystodictya sp. 

Orbiculoidea sp. 

Chonetes aff. C. oklahomensis. 

Productus afr. P. burlingtonensis. 

Pustula aff. P. alternata. 

Pugnax n. sp. 

Spirifer afr. S. grimesi. 

Spirifer sp. 

Brachythyris suborbicularis. 

Spiriferella? sp. 

6069. 1.7 miles north of east from Simonson ranch: 

Pustula aff. P. concentrica? Brachythyris suborbicularis. 

Productus aff. P. burlington- Cleiothyridina sublamellosa? 

ensis. Proetus n. sp. 

Spirifer aff. S. imbrex . 

The preceding three collections were taken from the base 

of the formation. 

6051 and 6382. Near southeast corner of sec. 13, T. 9 S., 

R.19W.: 

Amplexus afr. A. fragilis. 

Triplophyllum sp. 

Fenestella sp. 

Orbiculoidea sp. 

Rhipidomella sp. 

Schizophoria aff. S. swallowi. 

Chonetes aff. C. ornatus. 

Chonetes aff.,C. platynotus. 

Productus ovatus. 

Productus semireticulatus. 

Productus aff. P. parvus. 

Productus aff. P. setiger. 

Productus aff. P. keokuk. 

Productus afr. P. gallatinensis. 

Pustula aff. P. alternata. 

Pustula afr. P. subsulcata. 

Pustula aff. P. oklahomensis. 

Pustula aff. P. patula. 

Pustula aff. P. millespinosa. 

Pustula aff. P. biseriata? 

Pustula n. sp. 

Pustula? sp. 


Rhynchopora? aff. R. cooperensis. 

Rhynchopora sp. 

Cranaena aff. C. globosa. 

Spirifer afr. S. rostellatus. 

Spirifer sp. 

Brachythyris suborbicularis. 

Reticularia aff. R. pseudolineata. 

Spiriferina afr. S. solidirostris. 

Syringothyris sp. 

Composita sp. 

Eumetria verneuiliana. 

Hustedia aff. H. mormoni. 

Solenomya? sp. 

Streblopteria? sp. 

Deltopecten sp. 

Worthenia? sp. 

Pleurotomaria sp. 

Platyceras aff. P. capax. 

This collection came from a horizon about 1,050 feet above 

the base of the formation. 

Collection8 from the western facies 

6274. Accident Canyon, east of cabin: 

Productella hirsutiformis. 

Leiorhynchus carboniferum var. polypleurum. 

This lot came from the sandstone at the base of the formation 

and seems to contain the fauna of the Herat shale member. 

It is quite possible that this occurs at several horizons. 

6366. South side of Ochre 

6,886·foot hill: 


Triplophyllum afr. T. centrale. 


Stenopora aff. S. ramosa. 


Rhipidomella? sp. 


Productus aff. P. burlington­


ensis. 

Productus aff. P. setiger. 

Mountain, 2,500 feet east of 


Productus sp. 


Pustula aff. P. alternata. 


Pustula aff. P. subsulcata. 


Pustula? sp. 


Spirifer aff. S. rostellatus. 


Brachythyris suborbicularis . 

CARBONIFEROUS SYSTEM 29 

6367. 250 feet north of 6366: 

Triplophyllum sp. Pustula afr. P. concentrica. 

Chonetes afr. C. platynotus. Pustula afr. P. subsulcata. 

Productus ovatus. Pustula aff. P. moorefieldana. 

Productus ovatu8 var. latior? Pustula aff. P. oklahomensis. 

Productus afr. P. mesialis. Spirifer afr. S. increbescens. 

Productus sp. Reticularia afr. R. pseudoProductus afr. P. setiger. lineata. 

Pustula alternata. Spirifer afr. S. rostellatus. 

Pustula afr. P. biseriata. Spiriferella sp. 

6368. 250 feet north of 6367: 

Favosites sp. Spiriferina aff. S. subelliptica' 

Triplophyllum sp. Composita sp. 

Echinocrinus sp. Cleiothyridina sublamellosa 

Productus ovatus. var. 

Productus afr. P. mesialis. Hustedia afr. H. multicostata. 

Brachythyris afr. B. suborbicularis. 

6369. 100 feet north of 6368: 

Echinocrinus sp. Cranaena afr. C. subglobosa. 

Chonetes afr. C. oklahomensis. Composita sp. 

Productus afr. P. mesialis. Cleiothyrldina sublamellosa. 

Productus sp. Leptodesma sp. 

6065. 2,100 feet south-southeast of hill 7150, south side of 

Ochre Mountain: 

Trlplophyllum afr. T. centrale. Pustula afr. P. subsulcata. 

Schizophoria afr. S. swallowi. Spirifer aff. S. increbescens. 

Chonetes afr. C. oklahomensis. Spirifer aff. S. grimesi. 

Productus ovatus. Spiriferella? sp. 

Productus afr. P. mesialis. 

This lot was taken near the top of the formation. 

6319. 1,000 feet west of 6,964-foot point on southwest side 

of Dutch Mountain: 

Zaphrentis afr. Z. excentrica.! Fenestella sp. 

Crinoidal fragments. Productus ovatus? 

6322. 1,000 feet north of cabin in Royal Gulch: 

Michelinia afr. M. meekana. Productus aff. P. illflatu~. 

Triplophyllum afr. T. centrale. Productus afr. P. semireticuZaphrentis aff. Z. excentrica. latus. 

Stenopora? sp. Spirifer sp. 

Fenestella sp. Orthoceras? sp. 

These two collections were taken from beds rather high in 

the formation. They present an aspect rather different from 

the other collections and one that resembles some of the collections from the Oquirrh .formation. 

OCHRE MOUNTAIN LIMESTON]<~ (UPPER MISSISSIPl'IAN) 

Distribution.-The Ochre Mountain limestone is exposed in several places within the quadrangle. The 

largest exposure is on Ochre Mountain, which is in 

large part underlain by the formation and from which 

it takes its name. Dutch Mountain is also capped 

by this limestone, and there are other outcrops along 

the northern border of the quadrangle and in a belt 

along Trail Gulch. Smaller areas of the formation 

are found at the borders of the quartz monzonite stock 

and as roof pendants within it from Pool Canyon and 

the Rube mine south to Clifton. Still another locality 

is north and south of Overland Canyon from the Midas 

mine westward into Blood Canyon. 

Although the association of these outcrops with distinctive areas of the Manning Canyon and Oquirrh 

formations shows that some of them must represent 

a central and some a western facies, no lithologic distinction can be drawn between exposures definitely 

belonging to the one or the other. Isolated outcrops 

or those in fault contact with the surrounding sedimentary rocks therefore cannot readily be placed in their 

proper facies, except by reason of their relations to 

nearby outcrops or to structural features such as the 

thrusts. The outcrops in the vicinity of Overland 

Canyon, together with those in which the Western 

Utah, United States, and Cane Springs mines are located, have been referred to the central facies, and the 

remainder to the western facies. 

The area of limestone near Clifton may possibly be 

:Madison limestone, and the portion of the roof pendant north of Clifton mapped as Ochre Mountain limestone may belong rather to the Woodman formation, 

but for the reasons previously given they are regarded 

as belonging to the Ochre Mountain limestone. On 

the other hand, a fossil collection from hill 6267, on 

the south side of North Pass Canyon, was doubtfully 

referred by Mr. Girty to the Ochre Mountain limestone 

but for the reasons given in the description of the 

Woodman formation, to which another collection from 

this locality was referred, it seems more probable that 

these beds are part of the Oquirrh formation. 

Lithology.-The Ochre Mountain limestone is composed chiefly of rather thick bedded limestone. Near 

the base the limestone contains a considerable amount 

of chert, and near the top a smaller amount. About 

1,700 feet above the base of the western facies is a 

thin bed of black shale, which has been mapped separately as the Herat shale member. This is also 

present in the central facies. 

The contact of the formation with the underlying 

Woodman formation was seen only on the south and 

west sides of Ochre Mountain. Here laminae of sandy 

limestone, similar to that in the Woodman, are found 

several hundred feet above the lowest bed of massive 

limestone, which was chosen as the base of the Ochre 

Mountain limestone. 

The limestone beds are similar in appearance 

throughout the formation. They are commonly 

brownish gray on freshly broken surfaces and weather 

to light bluish gray. They are usually fine-grained, 

but coarser-grained beds occur locally. Individual 

beds may be as much as 10 feet in thickness, and almost 

all are more than 1 foot thick. In a few places thinnerbedded limestones are found. These contain a much 

larger proportion of insoluble material than the normal 

pure limestones and weather to hues of yellow and 

pink. 

The basal few hundred feet of the formation includes 

beds that contain large amounts of chert, in some beds 

considerably more than half. The chert is generally 
30 GOLD HILL MINING DISTRICT, UTAH 

light gray but weathers to a characteristic tan. The 

chert lenses and masses are everywhere highly shattered. In the upper cherty zone, which is less pronounced, the chert is present in the form of small 

nodules and stringers. The limestone beds included 

in the upper zone contain more sand than is genernlly 

present elsewhere. 

Near the intrusive rock the formation has been 

bleached and recrystallized, and in some beds silicate 

minerals have replaced the calcium carbonate in varying amounts. In other places not visibly related to 

areas of intnlsive rocks the limestone has been changed 

to dolomite, the alteration causing a change in the 

color of the weathered surface to a dull gray. These 

alterations are described in more detail on pages 91-94. 

Herat shale member.-The Herat shale member has 

been mapped at several places on the south side of 

Ochre Mountain, in Blood Canyon, and north and 

west of Clifton. The name is taken from the Herat 

mine near Clifton. Outcrops of the shale are rare, 

and it may be present at several places not shown on 

the map. The member is made up of black shale 

with thin lenses of sandstone. In most outcrops it 

has been the site of movements parallel to the bedding, 

with the result that its thickness is extremely variable, 

ranging from almost nothing to about 50 feet. In 

two of the exposures on Ochre Mountain the limestone 

beneath the shale, which is normally only slightly 

sandy, has been rather thoroughly silicified. In many 

respects the Herat shale member is similar to the 

stratigraphically higher Manning Canyon formation, 

and in the absence of fossils it is often difficult to distinguish the two. 

Thickness.--A complete section of the Ochre Mountain limestone was not found within the quadrangle. 

An approximation to the true thickness may be obtained by assuming that the central and western facies 

have the same thickness and that the Herat shale member has the same position in both facies. Both assumptions are probably open to question, and the result 

must be regarded merely as indicating the order of 

magnitude of the thickness. It is based upon an estimate of the thickness from the base of the western 

facies of the formation up to the Herat shale member, 

made at two places on the south side of Ochre Mountain; and an estimate of the thickness from the shale 

to the top of the central facies of the formation, made 

along Overland Canyon. These estimates were, respectively, 1,700 feet and 2,800 feet, indicating a total 

thickness of 4,500 feet. The figures were obtained by 

scaling the thickness from the geologic cross sections 

and are therefore only rough approximations, but more 

r(lfined mC!lsurements did not seem justified in view 

of the assumptions made. 

Age and correlation.-'1'he Ochre Mountain limestone, like the Woodman formation, is of upper 

Mississippian age. Mr. Girty's notes on the difficulties 

in distinguishing between the faunas of the two formations were quoted under the Woodman formation 

(p. 28) and need not be repeated here. The formation 

most nearly equivalent to the Ochre Mountain limestone is the "Great Blue" limestone in the Oquirrh 

Range.76 The formation is probably also more or less 

equivalent to the upper portions of the Brazer limestone of northeastern Utah 77 and southeastern Idaho.78 

Mr. Girty's determinations of the fossils in the 

collections are as follows: 

Collection from Ihe cenlral facies 

6325. Blood Canyon, north of spring: 

Triplophyllum sp. Girtyella indianensis'? 

Campophyllllm sp. Composita sp. 

Fenestella sp. Cleiothyridina sublamellosa? 

Schizophoria aff. S. Rwallowi? Cleiothyridina? n. sp. 

Orthotetes 8p. Bellerophon sp. 

Productus aff. P. parvus. 

This is the only eollection from the central facies. Metamorphism by the quartz monzonite stock appears to have 

destroyed most of the fossils originally present in it. 

Collections from I he weslern f acics 

Because of the difficulties in determining the throws of the 

numerous faults that cut the Ochre Mountain limestone, no 

attempt is made to list the collections in their proper stratigraphic order. The collections from the Herat shale, which is 

distinctive lithologically, are listed separately. 

5865. a,300 feet N. 60° 'V. from summit above Garrison 

Monster mine: 

Crinoid columnals. I Bellerophon'? sp. 

Levidentalium? sp. 

5866. West side of Oehre Mountain at base of rioge on south 

side of northernmm;t canyon: 

Produetus ovatus. 

Stenopora sp. 

Crinoid columnals. 

Productus aff. P. parvus. 

Rhombopora? sp. DiaphragmuB elegans? 

Fenestella, several sp. Spirifer aff. S. pellensis. 

Schizophoria sp. Cleiothyridina sublamellosa. 

.5866a. Same canyon as 5866, halfway up ridge: 


Product us brazerianus. 


5866b. Same canyon as 5866, jus~ below summit: 


Campophyllum? sp. 


5866e. Same canyon as 5866, at head of canyon: 


Eu~helllus aff. E. randolphen- i Holopea? sp. . . 

,ns. I Orthoceras aff. O. ehoctawense. 

5866d. Same canyon as 5866, divide at head of !l()rth branch: 

Syringopora sp. 

5866e. Same canyon as 5866, 400 feet above gravel on northern ridge: 

Spiriferella'r sp. 

" Gilluly, James, Geology and ore deposits of the Stockton and Fairfield quad 

rangles, Utah: U.S. GeoL Survey Prof. Paper 173, pp. 29-31, 1932, 

71 Richardson, G. B., The Paleozoic section in northern Utah: Am. Jour. Sci 

4th seL, vol. 36, p. 413, 1913. 

"Mansfield, G. R.• Geography, geology, and mineral re:5ourceg of part of sour 

eastern Idaho: U.S, Cleol. Survey Prof. Paper 152, pp. 63-71, 1927, 
CARBONIFEROUS SYSTEM 31 

6044. 1,000 feet southwest of hill 6634, on southwest side of 

Ochre Mountain: 

Stenopora alI. S. mutabilis. Productus inflatus? 

Stenopora sp. Spirifer alI. S. pellensis. 

Meekopora? sp. Spirifer alI. S. brazerianus. 

Chonetes sp. Spiriferella? n. sp. 

Productus semireticulatus. H ustedia multicostata? 

Productus ovatus? Griffithides sp. 

This eollection was obtained near the base of the formation 

6045. Due south of peak 6886, on south side of Ochre 

Mountain, at an altitude of 6,750 feet: 

Productus alI. P. parvus. ISpirifer alI. S. pellensis. 

Dielasma sp. Composita sulcata? 

6059. 1,500 feet east-southeast of 6,975-foot closed contour 

on south side of Ochre Mountain: 

Productus inflatus. ISpirifer alI. S. pellensi3. 

Pustula alI. P. moorefieldana. Spiriferella? n. sp. 

6060. Just west of hill 6634, on southwest side of Ochre 

Mountain: 

Productus gallatinensis? I

Composita sulcata? 

Pustula alI. P. genevievensis. Cleiothyridina sublamellosa. 

6062. 1,200 feet north of peak 7182, on ridge line of Ochre 

Mountain: 

Productus ovatus. IDielasma n. sp. 

Diaphragmus elegans? 

6063. 1,500 feet west of 7,150-foot peak on south side of 

Ochre Mountain: 

Productella hirsutiformis. Deltopecten alI. D. batesvillPustula alI. P. subsulcata. emliS. IBrachymetopus sp. 

This collection came from the limestone immediately beneath 

the Herat shale. 

6067. West of mouth of Accident Canyon, on north side of 

Dutch Mountain: 

Lithostrotionella sp. 

6072. 1,000 feet south-southeast of peak 7150, on south side 

of Ochre Mountain: 


Amplexus sp. IFenestella, several sp. 


Echinocrinus sp. 


This collection was obtained near the base of the formation. 

6075. 200 yards southeast of spring at Clifton: 

Syringopora surcularia. Amplexus sp. 

Cladochonus sp. Fenestella sp. 

Campophyllum sp. Cystodictya sp. 

Triplophyllum sp. Schizophoria alI. S. swallowi. 

Lithostrotionella sp. Euomphalus utahensis? 

[Mr. Girty regards this as possibly of Madison age, but, for 

the reason given above, the exposure has been mapped as 

Ochre Mountain limestone.] 

6277. 1,000 feet north of Clifton: 

'£<'istulipora sp. Spirifer alI. S. pellensis. 

Fenestella sp. Spiriferina transversa. 

Productus ovatus. Reticularia sp. 

Productus alI. P. setiger. Cleiothyridina sublamellosa. 

Pustula alI. P. concentriQA. Aviculipecten alI. A. spinulifer. 

Pustula alI. P. biseriata. Platyceras sp. 

Productella hirsutiformis? Griffithides sp. 

[Mr. Girty states that this collection would suit him better as 

Woodman, but for the reasons noted above it is here included 

in the Ochre Mountain limestone.] 

6373. 6,475-foot hill on southeast side of Ochre Mountain: 

Productus ovatus. I

Camarotoechia alI. C. mutata. 

Diaphragmus elegans? Camarotoechia sp. 

[Mr. Girty notes that this lot "is in its very meager way sui 

generis. It does not look like Ochre Mountain, but then I do 

not know what it does look like."] ­

6391. Southwest of highest summit of Ochre Mountain: 

Fistulipora sp. Spiriferina spinosa. 


Stenopora sp. 
 Ambocoelia fayettevillensis? 

Rhombopora sp. Composita subquadrata var. 

Chonetes oklahomensis. lateralis. 

Productus semireticulatus. Composita n. sp. 

Avonia arkansana? Cleiothyridina sublamellosa. 

Girtyella indianens is. Pectinopsis squamula? 

Spirifer arkansanus? Pectinopsis jenneyi. 

Spirifer alI. S. tenuimarginatus. Griffithides sp. 

Reticularia sp. Paraparchites sp. 

Spiriferina transversa. 

This collection came from a horizon above the Herat shale. 

6045 and 6365. Same locality as 6063: 

Lingula alI. L. halli. Leiorhynchus carboniferum. 

Orbiculoidea alI. O. bates- Cleiothyridina sublamellosa. 

villensiB. DeJtopecten catactus. 

Crania? sp. Deltopecten n. sp. 

Productella hirsutiformis. Pectinopsis squamula. 

Pustula moorefieldana var. Pleurotomaria? sp. 


pusilla. 
 Euomphalus? sp. 

Pustula subsulcata. Ostracoda. 

Diaphragmus elegans. 

6370. About 50 fcet up the slope to summit above bench at 

an altitude of about 7,000 feet on south side of Ochre Mountain: 

Cladochonus sp. Deltopecten catactus? 

Triplophyllum sp. Br/lchymetopus? sp. 

Pustula alI. P. subsulcata? Ostracoda. 

Leiorhynchus carboniferum. 

The two preceding collections are from the Herat shale 

member. The fauna is clearly the fauna of the White Pine 

shale of the Eureka district, N ev. A similar fauna was found 

near the base of the Woodman formation. 

MANNING CANYON FORMATION (UPPER MISSISSIPPIAN? 

AND PENNSYLVANIAN) 

Distribution.-The Manning Canyon formation was 

named by Gilluly 79 in the Oquirrh Range, Utah, where 

rocks of similar lithology have essentially the same 

stratigraphic position as those so designated in the 

Gold Hill region. 

The chief group of exposures of the Manning Canyon 

formation are found in a belt 2 miles in maximum width 

that extends from the head of Gold Hill Wash northward to the south side of Dutch Mountain. Most of 

these exposures have been assigned, on the basis either 

of lithology or of relations to the overlying formation, 

to the central facies. Several of the more westerly 

outcrops, however, belong to the western facies. 

These include the exposures above the Ochre Mountain 

thrust in the vicinity of the Ochre Springs, the small 

areas beneath the two down-faulted blocks of the 

Oquirrh formation on Ochre Mountain, and the ex­

" Gilluly, James, Geology and ore deposits of the Stockton and Fairfield quad· 

rangles, Utah: U.S. OeoL Survey Prof. Paper 173, pp, 3;-,% 1232, 
32 GOLD HILL MINING DISTRICT, UTAH 

posure on the southwest flank of Dutch Mountain 

northwest of hill 6566. 

Smaller outcrops occur on the northwest side of 

Dutch Mountain; just east of the Western Utah 

Copper Co.'s mine on Gold Hill; and at several places 

in Blood Canyon, in Overland Canyon, and near the 

Midas mine. The outcrop on the northwest side of 

Dutch Mountain belongs to the western facies of the 

formation; the remainder to the central facies. 

Lithology.-The two facies of the Manning Canyon 

formation are composed almost entirely of quartzite, 

sandy shale, and black shale. The quartzite is dark 

gray to black on fresh fracture, fine-grained, and in 

many places finely laminated. These beds generally 

weather to rusty or brownish colors. Many of the 

beds appear to be lenticular. The black shale is 

similar to that in the Herat shale member of the Ochre 

Mountain limestone. In all the exposures of the formation seen there was either considerable alteration 

due to nearby intrusive masses or abundant crushing 

and slipping as a result of faulting. Beds of reddishweathering dark limestone a foot or so thick are 

present sparingly. 

The central facies contains somewhat more quartzite than the western facies, but its chief distinction lies 

in the scarcity of limestone. In most outcrops of this 

facies limestone is entirely absent and the top of the 

formation has been drawn at the base of the lowest 

limestone. This line also approximately marks the 

upper limit of black-shale beds more than an inch or 

so in thickness. Some thin limestone beds, however, 

were observed in the exposures just west of the town 

of Gold Hill and on the east slope of Gold Hill, both of 

which are thought to belong in the central facies. In 

the western facies several thin beds of limestone occur 

in the upper part of the formation, and the upper 

boundary was placed at the top of the highest black 

shale. 

In both facies the thickness of the quartzite beds is 

variable. Locally, as in the exposures of the central 

facies east and north of the northern Ochre Spring, 

quartzite appears to make up the greater part of the 

formation, but in the much thinner section exposed on 

the south side of Pool Canyon, which is of the same 

facies, quartzite beds are comparatively rare. 

Thicknes8.-Tht;l thickness of the formation is 

variable, and nowhere was a section found that was 

thought to represent the true thickness. South of 

Pool Canyon on Dutch Mountain the apparent thickness in places is 50 feet or less, but to the south of the 

Ferber Road about 2 miles west of Gold Hill it is 

nearer 1,000 feet. Near the Midas mine, where the 

beds are considerably metamorphosed but seem to 

have suffered only minor faulting, the thickness is 

about 450 feet. The figures given are all for the 

central facies. The western facies appears to show 

less variation, but this is probably because there are 

fewAr exposures. 

Age and correlation.-Two faunas were obtained from 

the Manning Canyon formation. One of these is represented ~y the three following collections, identified 

by G. H. Girty: 

6327. 4,500 feet northwest of spring in Blood Canyon: 

Solenomya? n. sp. aff. S'I Yoldia aff. Y. levistriata. 

anodontoides. Goniatites? sp. 

Nueula? sp. 

6348. 2,000 feet southeast of benchmark 5885 on Ferber 

Road: 

Naiadites? sp. 

6381. Dump from northern Oehre Spring: 

Nucula aff. N. anodontoides. I Phanerotrema? sp. 

Leda sp. 

The first two lots represent the central facies of the 

formation. The third lot is from a locality where 

outcrops of the two facies are brought into contact 

by the Ochre Mountain thrust, and its proper assignment is somewhat doubtful. An assignment to the 

western facies, however, seems more probable. Mr. 

Girty has prepared the following note on these collections: 

Insofar as faunas limited to so few species can be said to have 

a faunal facies each of these collections is almost unique. Lot 

6381 might not be exceptional if the usual quota of brachiopods 

and bryozoans were present and if the extremely ill-preserved 

fossils did not prove to belong to alien species. All the ordinary 

Pottsville brachiopods are also from lot 6327, and in 

addition we have the large and striking form listed as Solenomya'l 

and the large coiled shell that probably belongs in one of the 

goniatite genera. Lot 6348 is still diffcrent. Aside from the 

pinnule of a fern, this collection contains only a small pelecypod 

together. with fragments of a somewhat larger one. The larger 

fragments suggest the form so common in the nonmarine Pottsville of the Applachian region, which is usually cited as Naiadiies 

elongatus. The smaller but also ill-preserved specimens can 

scarcely be N. elongatus unless they are immature as well as 

somewhat distorted, which is quite possible. On the other hand, 

it is possible that none of the specimens belongs to N. elongatus 

or even to the genus Naiadites. Other genera, such as Myalina, 

give us species very similar in appearance, and specimens rarely 

afford any evidenee as to their true generic position. These 

facts are important, inasmuch as Naiadites is supposed to be a 

fresh-water or at least a nonmarine genus, whereas lvfyalina is 

distinctly marine. Instead of themselves affording evidence of 

the marine or nonmarine origin of deposits by their generic 

characters, these forms often have to be given a generic assignment on the strength of the marine or nonmarine origin of the 

deposita as determined on other evidence. When we were 

making this collection (lot 6348) I remember suggesting that 

it might be of nonmarine origin because of a certain parallel 

with the nonmarine Pottsville of the East. In the East, however, the evidence of one collection is corroborated by hundreds 

of others, indicating nonmarine conditions that extended over 

wide areas and persisted through long periods of time. Here, 

on the other hand, the evidence of one collection is contradicted 

by that of others, for lot 6327 can scarcely be nonmarine and 

still less lot 6381. The peculiarities of these three lots are probably to be attributed rather to the character of the bottom and 

to distance from shore than to the fresh or brackish condition 

of the waters. 

The second fauna is found both in the upper portion 

of the Manning Canyon formation and in the basal 
CARBONIFEROUS SYSTEM 33 

portion of the overlying Oquirrh formation. It is 

considered by Mr. Girty to indicate a lower Pennsylvanian age and to be approximately equivalent to the 

Pottsville formation of the eastern United States. 

With one exception, collections of this fauna from the 

Manning Canyon formation were found in the western 

facies of the formation. Mr. Girty has made the following identifications: 

6281. 600 feet northwest of old smelter west of Gold Hill: 

Orbieuloidea sp. 

Crania modesto.. 

Schizophoria texana. 

Derbya robusta. 

Productus ovatus? 

Productus ovatus var. minor. 

Productus aft'. P. gallatinensis. 

Composita ozarkana? 


Leda bellistriata? 


Myalina perniformis. 


Astartella aft'. A. compacta. 


Pleurophorus tropidophoruB. 


Bacanopsis aft'. B. meekana. 


Griffithides morrowensis? 


This collection is from thc central facies. 


6276. 1,000 feet west of hill 6337, northeast side of Ochre 


Mountain: 


Streblotrypa sp. 


Lingula carbonaria? 


Productus n. sp. 


Productus ovatus var. minor. 


Pugnoides osagensis? 


Dielasma? sp. 


Spirifer opimus var. occiden­


talis. 

: Spiriferina spinosa. 

'Composita subquadrata var. 

lateralis. 

Edmondia aft'. E. mortonensis. 

Deltopecten occidentalis. 

Pectinopsis n. sp. 

Pectinopsis n. sp. 

Griffithides morrowensis? 

6374. 1,000 feet north of hill 6256, at head of Gold Hill Wash: 

Triplophyllum sp. 


Leioclema sp. b. 


Lingula carbonaria? 


Orbiculoides meekana? 


RhipidomeUa aft'. R. penniana. 


Derbya robusta. 


Productus cora. 


Productus ovatus var. minor. 


Productus n. sp. 


Pustula? sp. 


Avonia aft'. A. arkansana. 


Pugnoidcs n. IIp. 


Pugnoides osagensis var. per­


costata? 

Spirifer opimus. 

Spirifer opimus var. occidentalis. 

Spiriferina transversa. 

Composita ozarkana. 

Cleiothyridina pecosi. 

Myalina perniformis. 

Myalina aft'. M. arkansana. 

Modiola subelliptica. 

Deltopecten occidentalis. 

Pterinopecten? sp. 

Pectinopsis n. sp. 

Pectinopsis n. sp. 

Pleurophorns aft'. P. oblongus. 

Platyceras n. sp. 

Griffithides morrowensis? 

6377. 1,000 feet northeast of benchmark 5723 on Lincoln 

Highway south of Gold Hill: 


Triplophyllum sp. 


Polypora sp. b. 


Cystodietya sp. b. 


Productus ovatus var. minor. 


Avonia aft'. A. arkansana? 


Spirifer opimus vaT. occidentalis. 

Spirifcrina trallsversa. 

Composita ozarkana. 

Cleiothyridina pecosi? 

Parallelodon aft'. P. pergibbosum. 

A viculipecten sp. 

Astartella aft'. A. compacta. 

Pleurophorus? sp. 

Phanerotrema? sp. 

Bulimorpha aft'. B. chrysalis. 

Eotrochus? sp. 

Griffithides morrowensis? 

6378. 1,000 feet wcst-northwest of benchmark 5723 on 

Lincoln Highway south of Gold Hill: 

Rhipidomella aft'. R. penniana. 


Derbya robusta. 


Productus cora? 


Productus ovatus var. minor. 


Productus n. "p. 


Productus sp. b. 


Avonia aft'. A. arkansana. 


Spirifer opimus. 


Composita ozarkana. 


Cleiothyridina pecosi. 


Deltopecten occidentalis. 


Modiola subelliptica? 


Bellerophon aft'. B. sublevis. 


6380. From dump of southern Ochre Spring: 

Echinocrinus sp. Chonetes arkansanus. 

Fistulipora sp. b. Pustula globosa var. 

Stenopora sp. a. Spirifer opimus. 

Batostomella sp. Spirifer sp. 

Fenestella sp. Composita sp. 

Polypora sp. a. Cleiothyridina pecosi. 

Ptilopora? sp. Deltopecten occidentalis? 

Cystodictya sp. a. Griffithides morrowensis? 

Rhipidomella aft'. R. penniana. Ostracoda indet. 

The preceding five collections are from the western facies. 

MISSISSIPPIAN·PENNSYLVANIAN CONTAC'l' 

The contact between the Mississippian and Pennsylvanian in several places in Utah and Idaho has 

been described as unconformable.su In the Gold Hill 

quadrangle the presence of Pennsylvanian fossils in 

the Manning Canyon formation and Mississippian 

fossils in the underlying Ochre Mountain limestone, 

the variations in thickness of the Manning Canyon, 

and the peculiar character of the faunas found in three 

of the Manning Canyon collections would seem, in the 

absence of other evidence, to indicate that such an 

unconformity exists here at the base of the Manning 

Canyon. The contact between the Ochre Mountain 

and the Manning Canyon is well exposed only on the 

bottom level of the Cane Springs mine, but here the 

contact seems clearly to be gradational rather than 

unconformable. The explanation of this somewhat 

conflicting evidence may perhaps be furnished by the 

type locality of the Manning Canyon in the Oquirrh 

Mountains,81 which contains late Mississippian fossils 

at its base and Pennsylvanian fossils near the top, the 

break occurring within the formation. 

OQUIRRH FORMATION (PENNSYLVANIAN AND PERMIAN) 

The Oquirrh formation was named by Gilluly 82 for 

the Oquirrh Range, in Utah, where there is an unusually thick series of Pennsylvanian rocks, similar 

stratigraphically to the rocks in Gold HilL 

Distribution.-The Oquirrh formation has a wider 

distribution within the quadrangle than any other of 

the Paleozoic formations. Two large areas and several 

smaller ones are underlain chiefly by it. The southern 

of the two large areas extends from North Pass and 

Christiansen Canyons northward to the south side of 

Ochre Mountain and to Clifton. The northern area 

extends from Trail Gulch on Dutch Mountain to the 

western border of the quadrangle. Smaller areas are 

found near the eastern border of the quadrangle south 

of the continuation of Overland Canyon, immediately 

south and west of the town of Gold Hill; east of the 

Napoleon mine; and on the south side of Dutch 

Mountain. 

80 Blackwelder, Eliot, New light on the geology 01 the Wasatch Mountains, Utah: 

Oeol. Soc. America. Bull., vol. 21, PI'. 530-533, 1910. Richardson, O. B., The Paleozoic section in northern Utah: Am. Jour. Sci., 4th ser., vol. 36, p. 413, 1913. Mans· 

field, O. R., Oeography, geology, and mineral resources 01 part 01 southeastern 

Idaho: U.S. Oeol. Survey Prof. Paper 152, p. 73, 1927. 

" Gilluly, lames, Geology and ore deposits 01 the Stockton and Fairfield Quadrangles, Utah: U.S. 0001. Survey Prol. Paper 173, pp. 32-34, 1932. 

.. Idem, p. 34. 
34 GOLD HILL MINING DISTRICT, UTAH 

Lithology.-The Oquirrh formation, like the Manning Canyon, has two facies, which, however, are much 

more distinct than those in the Manning Canyon 

formation. The southern of the two large areas underlain by the fornlation and the areas around the town 

of Gold Hill are composed chiefly of the central facies; 

the areas west of Dutch Mountain, of the western 

facies. The exposures of the formation on the south 

side of Ochre Mountain, on the north and northeast 

borders of Clifton Flat, and in Rodenhouse Wash are 

also of the western facies. 

The central facies is made up of several different 

kinds of rocks, and each rock type represented is 

repeated over and over again throughout the section, 

although individual beds are generally lenticular. 

This makes it impossible to break up the formation 

into subdivisions, a course that would have made the 

study of the geologic structure much more simple. 

This facies is prevailingly sandy. Sandstones form 

perhaps half of the section, and sandy limestones and 

shales a large part of the remainder. Interbedded with 

these are numerous beds of limestone and dolomite and 

a few lenses of conglomerate. 

The sandstones are generally fine-grained rocks, 

rather dark gray on fresh fracture and deep reddish 

brovm on weathered surfaces. They are not at all 

resistant to erosion, and in places where they are abundant there are few outcrops, the surface being mostly 

covered by a sandy soil or by small blocks of rock. 

Many of these beds contain varying amounts of shaly 

material or of calcite. Near the base of the formation 

the sandstones in some places show a distinct lamination, which is in part due to the presence of thin films 

of carbonaceous matter similar to that which is so 

abundant in the underlying Manning Canyon formation. Near the quartz monzonite the sandstones are 

bleached to a dull white color and are notably harder. 

The limestone beds vary greatly in appearance. 

Many are fine-grained, dark bluish gray on fresh fracture and light bluish gray on the weathered surface. 

Such beds usually contain silica, either in the form of 

sandy laminae or as chert nodules or lenses. Locally, 

especially on the east side of Blood Canyon and in the 

low hills south and southeast of the ~lidas mine, there 

is a great deal of thin-bedded platy limestone which 

is nearly black on fresh fracture and purplish on 

weathering. Such beds are commonly very fossiliferous, containing especially large numbers of the characteristic Pennsylvanian fossil Fusv1ina. In many 

places ~-inch layers of this limestone alternate ",ith 

equally thin layers of brown sandstone and b1ack chert. 

Near the intrusions the limestones, like the sandstones, 

are thoroughly bleached; and many beds have been 

completely replaced by silicate minerals. 

Dolomite beds 8:re also found in many places. Some 

of these are clearly the result of a much later alteration 

of limestone; but others are, without much doubt, 

primary, in the sense that dolomitization occurred as a 

result of sedimentary processes. One of the most widespread of such dolomites is fine-grained bluish-gray 

rock, filled with round or spindle-shaped white dots, 

which, in part at least, represent poorly preserved 

Fusulinas. Other dolomites are similar to the beds 

of cherty limestone mentioned in the preceding paragraph, except for a slightly duller appearance. 

Locally the limestones and dolomites are conglomeratic and contain pebbles as much as 6 inches in 

diameter. The pebbles are in part limestone or dolomite, but the greater proportion are chert. A specimen of such a rock in which the chert fragments are. unusually small is illustrated in plate 5, F. This specimen 

is rather unusual in having an oolitic matrix, whereas 

generally the matrix is either fine-grained limestone 

or dolomite. Individual beds when traced along the 

strike may show a limestone matrix in one place and 

dolomite in another. Many of the conglomerate beds 

were found to pass into normal limestone or dolomite 

within a short distance, but others were traced along 

the strike for as much as 3 miles. 

Because of the angularity of the chert pebbles and 

also because of the presence of pebbles of limestone 

and dolomite, it would seem almost certain that the 

chert pebbles were deposited as such. If so, there are 

two possible sources for the pebbles-either from older 

chert-bearing rocks that were undergoing erosion at 

the time the conglomerates were being deposited or 

from a silica-rich layer deposited in essentially the 

same locality as the conglomerates and broken up by 

storm waves or currents, or perhaps by subaerial 

agencies brought into play by a temporary emergence 

before being covered by younger beds. In spite of 

the fact that the presence of limestone and dolomite 

pebbles is more easily explained by the first hypothesis, 

the second hypothesis seems the more attractive, because of the restriction of the pebbles to individual 

beds and because of the extremely slight extent of 

some of the beds. If this is the true explanation, it 

indicates that the siliceous ooze from which some cherts 

are thought to form 83 may harden rather soon after 

deposition. 

The western facies shows very little resemblance to 

the central. The amount of sandy material present 

is much smaller, and the chert-pebble and other conglomerates are lacking. 

At the base of this facies is a moderate thickness of 

light-colored sandstone, similar to that in the eastern 

facies. This appears to thin toward the north, as the 

amount -present in the northwestern part of Dutch 

Mountain is less than that found south of the 7,262­

foot peak at the head of Pool Canyon. 

Above the sandstone is a succession of thick-bedded 

limestones, nearly 3,000 feet thick. These limestones 

are similar to those in the Ochre Mountain limestone. 

"Tarr, W...'1.., in TwenhofeJ, W. R., A treatise on sedimentation. p. 384, 1926. 
CARBONIFEROUS SYSTEM 35 

Thin beds of sandstone are usually associated with 

them and help to distinquish the two formations, as 

does the abundance of Fusulina in the Pennsylvanian 

limestone. Locally these small fossils are so numerous 

as to ma,ke up a,n entire bed. The distribution of chert 

throughout the limestone series is erratic rather than 

limited to two rather distinct horizons, as in the Ochre 

Mountain limestone. In some places the limestones 

have been dolomitized. The dolomitization shows no 

relation to the bedding or other features of sedimentary 

structure but rather has occurred near faults or minor 

folds. It has given the rock a duller and grayer 

aspect than normaL 

Above the massively bedded limestone is about 

4,500 feet of dolomite and sandstone, with only minor 

amounts of limestone. The dolomite is rather light 

gray and medium-grained. Many beds contain darkgray chert nodules and stringers. Unlike the dolomites mentioned in the preceding paragraph, these beds 

are thought to be formed by sedimentary processes, 

as their distribution shows no relation to structural 

features and as the interbedded limestones where 

dolomitized have an altogether different appearance. 

The sandstones are for the most part mediumgrained gray rocks which weather to tints of light 

reddish-brown. Almost all have a moderately large 

content of calcite as a cement. In one specimen of 

cross-bedded sandstone obtained near the base of this 

portion of the formation the quartz grains, together 

with a very few of plagioclase, were surprisingly 

angular, especially when it is considered that the 

nearest shore of the Pennsylvanian sea is supposed to 

have been at least 100 miles away. In the upper 

1,500 feet of the formation as exposed on each side of 

Deep Creek sandstones are much more abundant. 

These beds weather to vivid hues of red and yellow, 

but a large part of the coloring material is thought to be 

derived from the weathering of nearby volcanic rocks. 

The limestones that are found in the upper division 

are similar to those making up the lower division. 

One characteristic zone is found about 3,800 feet 

above the base of the upper division. This was one 

of the two distinctive horizon markers on the western 

facies, the upper contact of the limestone series being 

the other. It is a poorly exposed zone of extremely 

cherty and sandy limestone and usually appears at 

the surface as a bench covered with fragments of 

black chert. This bed occurs at several places in the 

area westward from the low-lying hills west of Dutch 

Mountain. 

Thicknes8.-No accurate measurement of the thickness of the Oquirrh formation was made, because of 

the difficulty of correlating precisely the various short 

sections unaffected by folding or faulting. TM total 

thickness of the central facies could not be determined 

even if this were done, because the contact of this 

facies with the Permian was nowhere seen. Estimates 

from cross sections indicate a minimum thickness for 

this facies of 5,300 feet. The bottom and top of the 

western facies are both exposed in the northwestern 

portion of the area. A result which was obtained by 

piecing together estimates of thickness of the two 

divisions and which is believed to allow for the greater 

part of the folding and faulting points to a figure 

between 7,500 and 8,000 feet for the total thickness 

of this facies. 

Age and (]orrelatioll.--Mr. Girty has divided the 

fossil collections from the Oquirrh formation into three 

groups, representing three different ages. Near the 

base of the f()rmation in both the central and western 

facies, the fossils indicate a Pottsville or lower Pennsylvanian age. The remainder of the central facies 

and the greater part of the western facies contain 

fossils characteristic of the higher Pennsylvanian. 

Finally, near the top of the western facies, the fossils 

are similar to those found in the overlying formation, 

which is of Permian age. Mr. Girty has kindly 

provided the following notes: 

A sharp demarcation exists between the higher Pennsylvanian 

faunas and the Permian faunas of the Gold Hill district. It is 

true that specitlc distinctions among the Compositas do not 

amount to much, so that C. mira closely resembles C. 8ubtilita, 

and that Pustula subhorrida resembles, more or less closely, the 

species cited in these lists as Pustula aff, P. wallaciana, but either 

fauna, given a collection of reasonable size, can be recognized 

with ease and certainty. 

Naturally enough, this is less true of the faunas that occur in 

the higher Pennsylvanian and in the Pottsville. The fossils in 

the much disturbed strata of the Gold Hill district are not as a 

rule in a good state of preservation, so that specific differenccs, 

if not lost entirely, may have been overlooked. With a better 

understanding of individual species and a more complete 

knowledge of their range in the section, a more accurate distinction between the Pottsville and post-Pottsville faunas could 

probably be drawn. As it is, small collections of poorly preserved shells cannot be referred with any confidence. Considered in a broad way, with the stratigraphic data and the paleontologic data supplementing each other, one rather well marked 

distinction appears to exist between these two faunas. Most of 

the collections from the higher Pennsylvanian contain Fusulina 

in more or less abundance, whereas not one of the Pottsville 

collections contains any of these shells. Of course there are 

other differences between the faunas, but this is the most 

obvious one and so far as facts are available the most practical 

one. The distinction thus suggested works only one way, however. All the collections that contain F'usulina can be classcd 

as higher Pennsylvanian, but not all the collections that fail to 

contain FU8ulina can be classed as Pottsville, and of these, as 

already noted, certain small and nondescript collections must be 

assigned largely on the basis of their stratigraphic occurrence 

rather than upon the fossils which they contain. 

You are, I believe, recognizing a central and a western facies 

in the rock characters of the Pennsylvanian of the Gold Hill 

district. I am unable to make a like distinction in the faunas, 

though here again a nicer discrimination of species and closer 

attention to forms like the Bryozoa, to which I have been able 

to give only a summary treatment, might show differences that 

I have failed to recognize. It is true that in checking up the 

faunas that represent the two lithologic phases a number of 

species occur in one list and not in the other and especially a 

large number of species have been found in the central facie~. 

that appear to be absent from the western facies, but on the 

other hand the central collections outnumber the western 
36 GOLD HILL MINING DISTRICT, UTAH 

collections almost 2 to L Besides this, several of the western 

faunas possess striking and individual peculiarities which 

distinguish them as much from other western faunas as from 

any of the central faunas. In comparisons of this sort a species 

to be significant should occur repeatedly in one fauna and not 

at all in the other. In the present series of collections a single 

occurrence, let us say, in the central fauna might stand against 

about 22 nonoccurrences in the same fauna and about 15 nonoccurrences in the western fauna, so that it would not mean very 

much. The only striking instance of such a difference that 

would seem to be significant is invested in the form listed as 

Rhynchopora sp., which has been found only in the central 

fauna and which has been noted in five collections. In the 

present state of our knowledge, then, the central and western 

faunas do not differ recognizably, though differences that are 

now obscure may actually exist. 

Collections of Pottsville age 

6079. About one-third mile southeast of hill 6837, on west 

side of Blood Canyon: 


Derbya robusta. Composita ozarkana. 


Productus n. sp. Cleiothyridina pecosi. 

Productus ovatus var. minor. A viculipecten? sp. 

Spirifer opimus var. occiden- Lima? sp. 


talis. 
 Griffithides morrowensis? 

Spiriferina spinosa. 

6326. Blood Canyoll, 2,500 feet north-northwest of spring: 

Echinocrinus sp. Spirifer opimus. 

Fistulipora sp. Composita ozarkana. 

Derbya robusta? Cleiothyridina peeosi. 

Productus semireticulatus. Conocardium sp. 

Avonia aff. A. arkansana. 

6328. Blood Canyon, 5,000 feet west-northwest of spring: 

Derbya robusta? Spirifcr sp. 

Productus n. sp. Spiriferina spinosa. 

Spirifer opimus var. occiden­ Composita ozarkana. 


talis. 
 Cleiothyridina pecosi. 

The preceding three lots came from the central facies. The 

following lots represent the western facies. 

6064, 6070, 6372. 3,100 feet southeast of benchmark 6163, at 

north end of Clifton Flat: 

Sponge spicules. Spirifcr opimus. 

FistUlipora sp. b.? Spirifer opimus var. occidenStcnopora sp. c. talis? 

Rhombopora lepidodendroides. Spiriferina transversa. 

Leioclema sp. b. Composita ozarkana. 

Fenestella alf. F. tenax. Cleiothyridina pecosi. 

Orbiculoidea meekana? Hustedia sp. 

Derbya robusta. Schizodus? sp. 

Chonetes choteauensis. Deltopecten occidentalis. 

Productus n. sp. Deltopecten occidentalis var. 

Productus ovatlls var. minor. Deltopecten n. sp. 

Productus cora. Streblopteria n. sp. 

Avonia aff. A. arkansana? Pterinopecten? sp. 

Pustula sp. Pectinopsis jennyi? 

Dielasma sp. Pectinopsis n. sp. 

6333. Just west of saddle west of 7,262-foot summit on south 

side of Dutch Mountain: 

Cryptozoon? Schizophoria texana. 

Favosites n. sp. Derbya robusta. 

Fistulipora sp. b.? Productus n. sp. 

Stenopora sp. b. Productus sp. a. 

Anisotrypa sp. Productus ovatus var. minor. 

Leioclema sp. b. Avonia aff. A. arkansana. 

Pustula semipunctata. Composita ozarkana. 


Pugnoides n. sp. Composita subquadrata var. 


DielasIDI\ aff. D. bovidens. lateralis? 


Spirifer opimus. Cleiothyridina pecosi. 


Spirifer opimus var. occiden- Hustedia sp. 


talis. Edmondia? sp. 

Spiriferina spinosa. Pleurophorus? sp. 

6334. South of 6333, near sill of quartz monzonite porphyry: 

Orbiculoidea meekana? Acanthopecten carboniferus. 

Spirifer opimus var. occiden- Pectinopsis n. sp. 

talis. Deltopecten occidentalis. 

Spiriferina spinosa. Myalina perniformis. 

Composita ozarkana. Griffithides morrowensis? 

6335. About same horizon as 6334 and a few hundred feet 

west of it: 

Leioclema sp. a. Composita ozarkana. 

Schizophoria texana. Cleiothyridina pecosi. 

Derbya robusta. Acanthopecten carboniferus. 

Productus ovatus var. minor. Pinna aff. P. peracuta. 

A vonia aff. A. arkansana. Griffithides morrowensis? 

Spirifer opimus var. occidentalis. 

6336. About 100 feet stratigraphically abovc 6335: 

Orbiculoidea meekan!l? Spiriferopimus var.occidentalis. 

Crania modesta. Spiriferina spinosa. 

Derbya robusta. Composita ozarkana. 

Productus n. sp. Composita subquadrata var. 

Productus aff. P. gallatinensis. lateralis. 

Pugnoides osagensis var. per- Cleiothyridina pecosi. 

costata. Myalina perniformis. 

Dielasma sp. Griffithides morrowensis? 

6337. About 50 feet stratigraphically above 6336: 

Echinocrinus sp. Composita subquadrata var. 

Derbya robusta. lateralis? 

Productus n. sp. Cleiothyridina pecosi. 

Productus cora. Hustedia rnormoni? 

Productus ovatus var. minor. Parallelodon? sp. 

Productus aff. P. gallatinensis. Aviculipecten sp. 

Avonia aff. A. arkansana. Pterinopecten sp. 

Pugnoides n. sp. Deltopecten occidentalis. 

Spirifer opimus var. occiden- Euomphalus? sp. 

talis. Griffithides morrowensis? 

Spiriferina spinosa. Fish tooth. 

Composita ozarkana. 

6338. About ,'iO feet stratigraphically above 6337: 

Syringopora sp. Productus nolani. 

Spirorbis carbonaria. Productus sp. a. 

Ortonia sp. Avonia aff. A. arkansana. 

Hederella sp. Dielasma aff. D. hovidens. 

Stenopora sp. b. Spirifer opimus var. occidenRhombopora lepidodendroides. talis. 

Derbya robusta. Composita ozarkana. 

Chonetes platynotus? Cleiothyridina pecosi. 

Productus cora. I Griffithides morrowensis? 

6349. West side of Dutch Mountain near base, 3,500 feet 

east-southeast of benchmark 5369 on Ferber Road: 

Productus n. sp. Bucanopsis n. sp. 

Spirifer opimus var. occiden- Naticopsis n. sp. 


talis. 
 Pleurotomaria aff. P. beckSpirifer sp. withana. 

Spiriferlna spinosa. Schizostoma catilloides? 

Composita ozarkana. Platyceras sp. 

Cleiothyridina pecosi? Griffithides morrowensis? 

Myalina perniformis. Paraparchites sp. 

Modiola? sp. 
CARBONIFEROUS SYSTEM 37 

6078. South side of Ochre Mountain, 4,250 feet northnorthwest of benchmark 6149 on Lincoln Highway: 

Schizophoria texana. IPustula globosa var. 

Productus ovatus var. minor. Spiriferina spinosa. 

A vonia atf. A. arkansana. Composita ozarkana. 

6273. 1,000 feet north of hill 5688, at northwest tip of Dutch 

Mountain: 

Schizophoria texana. Spiriferina transversa. 

Productus nolani var. Composita ozarkana. 

Productus ovatus var. minor. Cleiothyridina pecosi? 

Spirifer opimus. Pleurophorus sp. 

Spiriferina spinosa. 

6316. About half a mile east-northeast of New York claim, 

on southwest side of Dutch Mountain: 

Lingula carbonaria? Composita ozarkana. 

Orbiculoidea meekana? Cleiothyridina pecosi. 

Productus n. sp. Myalina perniformis. 

Productus cora. Deltopecten occidentalis. 

Spirifer opimus. Platyceras sp. 

Spiriferina spinosa. Griffithides mOITowensis? 

6350. About 500 feet east of 6316: 

Productus semireticulatus. ISpirifer opimus var. occidentalis. 

6353. West side of Dutch Mountain, 2,000 feet northeast of 

hill 6518: 

Productus n. sp. \ Spirifer sp. 

Spirifer opimus var. occiden- Composita ozarkana. 

talis. 

6375. Same locality as 6374 (Manning Canyon formation) 

but just above road: 

Lingula carbonaria? Spiriferina spinosa. 


Derbya robusta. 
 Composita ozark ana. 

Productus n. sp. Cleiothyridina pecosi. 


Productus ovatus var. minor. 
 Hustedia sp. 


Productus sp. b. 
 Edmondia atf. E. mortonensis. 

A vonia atf. A. arkansana. Edmondia afr. E. circularis. 

A vonia atf. A. arkansana var. Deltopecten occidentalis. 

Spirifer opimus. Pectinopsis n. sp. 

Spirifer opimus var. occiden- Bellerophon atf. B. sublevis. 

talis? Griffithides morrowensis? 

Spiriferina transversa. 

6376. About 75 feet higher than 6375: 

Productus ovatus var. minor. 

Derbya robusta. 

Fistulipora sp. a. 

Avonia afr. A. arkansana. 

Chonetes choteauensis? Spirifer opimus var. occidenProductus n. sp. talis. 


Produetus cora. 


Collections of higher Pennsylvanian species 

The following 24 lots came from the central facies. 

6047. One-fourth mile northwest of peak 7660, in saddle on 

divide between Overland Canyon and North Pass Canyon: 

Campophyllum torquium? IMarginifera? sp. 

Rhombopora sp. Composita? sp. 

Chonetes afr. C. granulifer. Griffithides? sp. 

6048. East-west spur west of 7,300-foot closed contour on 

main ridge line of Deep Creek Mountains, about 200 feet 

stratigraphically below westernmost outcrops; 

Stenopora sp. Spiriferina spinosa. 

Derbya? sp. Composita subtilita. 

Spirifer opimus. I 

6049. Same as 6048, about 100 feet stratigraphically below 

6058: 


Fusulina sp. Rhombopora I e p i dod e n ­

Sponge? droides. 


Campophyllum torquium. Marginifera splendens? 


Polypora sp. Hustedia mormoni. 


6050. 1,000 feet north of 6058: 

Fenestella sp. ISpiriferina kentuckyensis. 

Rhombopora sp. Composita subtilita. 

Spirifer rockymontanus. 

6055. Same spur as 6048 but about 400 feet stratigraphically 

lower: 

Fusulina sp. Polypora sp. 

Campophyllum kansasense? Composita subtilita. 

Echinocrinus sp. Griffithides major? 

Stenopora sp. 

6056. 800 feet west-southwest of peak 7472, on main ridge 

line of Deep Creek Mountains: 

Fusulina sp. I Rhombopora sp. 

6057. Same spur as 6056 but about 200 feet stratigraphically 

lower: 

Syringopora n. sp. 

6058. Same spur as 6056 but about 500 feet stratigraphically 

lower: 


Syringopora sp. IPlagioglypta? sp. 


Campophyllum torquium. 


6066. 3,100 feet southeast of benchmark 6163 on Lincoln 

Highway: 


Echinocrinus sp. ISpiriferina kentuckyensis. 


Spirifer opimus. Composita subtilita. 


6071. 700 feet Horth-northwest of benchmark 5855 on Lincoln 

Highway: 

Campophyllum sp. I Crinoid stems. 

6073 and 6077. Near southeast corner of sec. 17, T. 9 S., R. 

19 W . (unsurveyed): 

Triplophyllum sp. Spirifer opimus. 

Michelinia sp. Cleiothyridina pecosi. 

Echinocrinus sp. Aviculipecten afr. A. coloradoFenestella aff. F. tenax. ensis. 

Productus cora. Pinna? peracuta. 

Pustula afr. P. biseriata. Paraparchites sp. 

Girtyella? sp. Kirkbya sp. 

6074. About three-quarters of a mile west-southwest of Montezuma Peak: 

Rhombopora Sp. IRhynchopora sp. 

Marginifera splendens? Spiriferina? sp. 

6076. Summit of peak 5800, half a mile southwe~t of U.S. 

Mineral Monument no. 7: 

F'usulina sp. Echinocrinus sp. 

Syringopora sp. Productus cora. 

Syringopora? (n. gen.?) sp. Pleurotomaria? sp. 

Campophyllum? sp. 

6290. South of mouth of Uiyabi Canyon: 

Fusulina sp. IProductus cora. 

Syringopora sp. Productus semireticulatus. 

Zaphrentis sp. 

6330. Southeast flank of Montezuma Peak, near mouth of 

gulch in which road leads westward to Midas mine: 

Fusulina sp. I Schwagerina? sp. 

6357. Lower slopes of center spur in Sheridan Canyon: 

Stenopora sp. ISpirifer opimua var. occiden· 

Derbya robusta? talis. 

Composita subtilita. 
38 GOLD HILL MINING DISTRICT, UTAH 

6358. About 200 feet stratigraphically lower than 6357: 6321. West side of Dutch Mountain 4,000 feet due west of 

Syringopora multattenuata. Productus semireticulatus. 6320:

Campophyllum kansasense? Spider sp. 

Stenopora aff. S. ramosa. Composita subtilita. 

Rhombopora sp. 

6359. AbQut 100 feet stratigraphically lower than 6358: 

Lophophyllum profundum? Rhynchopora sp. 

Productus semireticulatus. Squamularia perplexa? 

Pustula aff. P. semipunctata. Cleiothyridina pecosi. 

Pustula n. sp. aff. P. wallaciana. 

6360. About 100 feet stratigraphically lower than 6359: 

Fugulina gp. 


Syringopora gp. 


Campophyllum kansasense? 


Rhombopora sp. 


Productus cora. 


Productus semireticulatus. 


Marginifera splendens. 

Marginifera lasallensis? 

Rhynchopora sp. 

Spiriferina spinosa? 

Pleurotomaria sp. 

Omphalotrochus? sp. 

Syringopora aff. S. 

tenuata. 

Rhombopora sp. 

6362. Just west of 

maiu ridge line: 

.Fusulina sp. 

Syringopora aff. S. 

tenuata. 

6361. About 300 feet stratigraphically lower than 6360: 

mUltat-1 	Productus cora. 

Pustula semipunctata var. 

intersection of the spur of 6357 with 

Rhipidomella aff. R. carhomultat­ naria. 

Chonetes sp. 

Campophyllum torquium. Rhynchopora sp. 

Fenestella sp. Spiriferina spinosa. 

Polypora sp. Omphalotrochus sp. 

Rhombopora sp. 

6363. About a quarter of a mile south of 6362: 

Syringopora? sp. 


Echinocrinus sp. 


Enteletes? n. sp. 


Derbya aff. D. multistriata. 


Productus? sp. 


Spirifer n. sp.? 


Spiriferiua spinosa. 


Ambocoelia planicollvexa var. 


Composita subtilita. 


Pleurotomaria sp. 


6364. North of road leading to cabin just northeast of 

benchmark 5855, at southeast corner of Clifton Flat: 

Fusulina sp. 


Syringopora aff. S. multat­


tenuata. 

Campophyllum torquium? 

Cyathophyllum sUbcaespitosum? 

Echinocrinus sp. 

Polypora sp. 

Acanthoclatlia sp. 

Rhombopora lepidodendroides. 

Rhombopora sp. 

Cystodictya aff. C. inaequimarginata. 

The next 15 lots came from the westcrn facies of the formation. 

6317. 3,000 feet south of benchmark 5963 on ferber Road: 

Productus semireticulatus. lAvonia? sp. 

6318. 4,250 feet southwest of benchmark 5963 on Ferber Road: 

Productus sp. I Spirifer aff. S. triplicatus. 

6320. Southwest side of Dutch Mountain, 1,250 feet west of 

5,964-foot point: 

Schizophoria? sp.. Spirifer opimus var. occidenProductus cora. talis. 

Productus semireticulatus. Composita subtilita. 

Avonia? sp. 

Stenopora sp. Productus sp. 

Rhomboporasp. Spirifer sp. 

Rhipidomella aff. R. carbonaria. 

6331. A quarter of a mile north-northeast of A B claim, west 

side of Dutch Mountain: 

Fusulina sp. Rhombopora sp. 

Favosites? sp. 

Triplophyllum sp. I

Productus cora. 

6332. A quarter of a mile east of 6331: 

Fusulina sp. 


Syringopora sp. 


Campophyllum torquium. 


Fistulipora sp. 


Stenopora aff. S. carbonaria. 


Rhombopora sp. 


Derbya? sp. 


Productus semireticulatus. 

Productus n. sp.? 

Dielasma aff .. D. bovidens. 

Spirifer triplicatus. 

Composita subtilita. 

Omphalotrochus sp. 

6344. 1 mile southwest of hill 6060 (southern one of Twin 

Peaks) west of Dutch Mountain: 

Fusulina Sp. I Cyathophyllum subcaespitosum? 

6345. About 250 feet stratigraphically below 6344: 

Cladochonus sp. ! Marginifera splendens? 

Rhombopora sp. Spiriferina spinosa? 

Derbya? sp. I 

6346. In gulch north of 6344 and 6345 and stratigraphically 

between them: 

Syringopora sp. I Campophyllum sp. 

6351. Near hill 6360, on west side of Dutch Mountain: 

Streblotrypa sp. Margillifera splendens. 

Rhombopora sp. Spiriferina spinosa? j Polypora sp. 

6352. 2,000 feet north-northeast of hill 6518, on west side of 

Schizophoria n. sp. 


Meekella? sp. 


Chonetes aff. C. geinitzianu5. 


Productus cora. 


Productus n. sp. 


Productus semireticulatus. 


Pustula aff. P. semipunctata. 


Rhynchopora sp. 


Dielasma bovidens? 


Spiriferina spinosa var. 


6354 and 6354a. 1,000 feet west of hill 6518, on west side of 

Dutch Mountain: 

Crinoid columnals. Astartella n. sp. 

Echinocrinus sp. Goniospira? sp. 

Lingula carbonaria. Zygopleura? sp. 

Tegulifera? sp. 

6379. Same locality as 6378, of Pottsville age, but about 75 

Dutch Mountain: 


Fistulipora sp. 


Stenopora sp. 


Rhombopora sp. 


Productus semireticulatus. 


Productus cora. 


Pustula n. sp. aff. P. wallaciana. 

Spirifer opimus var. occidentalis. 

feet stratigraphically higher: 


Fistulipora sp. 


Rhombopora sp. 


Derbya robusta? 


Productus cora. 


Productus semireticulatus. 


Productus sp. 


Avonia sp 

Pustula n. sp. aff. P. wallaciana. 

Spirifel' aff. S. triplicatus. 

Squamularia perplexa. 

Composita subtilita. 

6583. North side of gulch from 6346: 

Fusulina sp. : Productus semireticulatus. 

Productus cora. 

In addition to these lots two others were collected 

on the south side of North Pass Canyon in rocks 
CARBONIFEROUS SYSTEM 39 

thought to be of this age, for the reasons given in the 

section on the Ochre Mountain limestone. It is 

entirely possible that these rocks are of Mississippian 

rather than Pennsylvanian age, but in the absence of 

the further field investigations that would be necessary 

to prove their correct assignment the two lots are 

listed here. 

6383. Lower eastern slopes of hill 6267, on south side of 

North Pass Canyon: 

Triplophyllum sp. I Productus aff. P. arcuatus. 

Productus ovatus. Spirifer aff. S. increbescells. 

Productus semireticulatus. Composita? sp. 

6384. Same as 6383 but just below summit: 

Echinocrinus sp. Pustula aff. P. biseriata. 

Fenestella sp. Pugnoides, several sp. indet. 

Chonetes aff. C. oklahomensis. Cranaena aff. C. glohosa. 

Productus ovatus. Spiriter aff. S. grimesi. 

Pustula aff. P. millespinosa. Composita? sp. 

Pustula aff. P. concentrica. Griffithides n. sp. 

Pustula n. sp. 

Mr. Girty writes as follows regarding these two 

collections: 

The fauna of lot 6383, which was included among the Ochre 

Mountain collections, is noncommittaL It might be Penllsylvanian; the faunal evidence is concessive but not confirmatory. 

The same question was raised with reference to lot 6384. 

Though the fauna comprised in this lot is peculiar, it fits in 

reasonably well \vith the Woodman fauna and very badly with 

the Pottsville or post-Pottsville as those faunas are at present 

known in the Gold Hill district. 

Collections oj Permian age 

These lots all came from the western facies. 

6339. Half a mile south-southeast of benchmark 5544, in 

Tank Wash: 

Derbya sp. Camarotoechia? sp. 

Pustula aff. P. signata. Heterelasma? sp. 

Puatula Bubhorrida. Spiriferina pulchra? 

Pustula subhorrida var. ruga- Compoaita ap. 

tula. Cleiothyridina n. ap. 

6340. Just weat of benchmark 5544 on Ferber Road: 

Leioclema? ap. Pustula subhorrida. 

Derbya aff. D. multistriata. Strophalosia'! n. sp. 

Puatula nevadensis. Dielasma? sp. 

Pustula aff. P. montpelierensis. Cleiothyridina n. sp. 

6341. A quarter of a mile west of 6340, about 50 feet stratigraphically lower: 

Derbya aff. D. robuata. I Pustula subhorrida var. ruga-


Pustula nevadensis? tula? 


Pustula subhorrida. 


6342. Near peak 5850, west of 6341: 

Leioclema? sp. I Pustula subhorrida val'. ruga-


Pustula nevadensis. tula? 


Pustula suhhorrida. Spiriferina Jlulchra. 


6343. 1,000 feet west of 6342: 

Pustula aubhorl'ida? i Composita subtilita. 

6356. 1,000 feet west of benchmark 5097 on Deep Creek. 011 

north side of gulch: 

Pustula subhorrida? IComposita subtilita? 

Productus ap. 

The collections here referred to the Permian are cited with 

varying degrees of confidence. Some of the collections are 

small or poorly preserved or both. Some also fail to contain 

the most characteristic species of the Spiriferina pulchra fauna 

and present a facies that is appreciably different though related. 

However, all the collections that possess individual or distinctive 

characters show a closer relationship to the Permian than to the 

Pennsylvanian faunas of the region. 

The formation as a whole is difficult to correlate 

with formations found in other districts. It is most 

closely comparable to the Oquirrh formation in the 

Stockton and Fairfield quadrangles 84 but appears to 

contain older beds at the base and younger ones at 

the top. It is less confidently correlated with the 

Weber quartzite 85 in the Wasatch Range and with the 

Ely limestone 86 of Nevada. 

GERSTER FORMATION (PERMIAN) 

Distribution.-The Gerster formation crops out 

within the Gold Hill quadrangle only in the narrow 

area west of Deep Creek. There is a small exposure 

on the south end of the hill west of benchmark 4984, 

but the largest outcrop occurs on the south side of 

Gerster Gulch, from which the formation is named. 

Another small area partly covered by volcanic rocks 

I was found west of benchmark 5097, about a quarter 

of a mile beyond the western border of the quadrangle. 

All these outcrops are placed without hesitation in the 

western facies of the Carboniferous. 

Lithology.-The Gerster formation is made up largely 

of thin-bedded sandy and shaly limestones, which are 

brownish gray on fresh surfaces and weather to yellowish brown or pink. The beds are from 2 inches to 1 

foot thick and generally have a concentration of sandy 

or shaly material along the bedding planes. These 

beds are richly fossiliferous in all the exposures seen. 

Locally thin beds of sandstone may be found, and in 

most exposures moderately thick beds of cherty limestone are also present. 

These beds are sharply set off from the underlying 

sandstones and dolomites of the Oquirrh formation by 

their lithology and especially by their abundant fossil 

content, which was the basis for mapping the contact 

between the two. In most places there is a thin bed 

i of sandstone at this contact, but no other evidence of 

discordance was found, and Mr. Girty's determination 

of a Permian age for some of the fossil collections in the 

upper portion of the Oquirrh formation suggests that 

the lithologic break is of minor importance. 

Thickness.-East of Deep Creek the Gerster formation has been removed by pre-Eocene (?) erosion, and 

to the west all but one of the outcrops are overlain 

by the Eocene (?) or by volcanic rocks. In the gulch 

south of that leading to Ferber, however, a closer measure of the original thickness may be obtained, as here 

If Gilluly, James, Geology and ore deposits of the Stockton and Fairfield 

quadrangles, Utah: U.S. Oeol. Survey Prof. Paper 173, pp. 34-38, 1932. 

15 Boutwell, J. M., Geology and ore deposits of the Park City district, IJtah: 

U.S. Geol. Survey Prof. Paper 77, pp. 4H9, 1912. 

'" Spencer, A. C., Geology and are deposits of Ely, Nev.: U.S. Geol. Survey Prof 

Paper 96, pp. 27-28, 1917. 
Missi sSippian 

Devonian 

OF 

feet 

l'tf(fn ? PENNSYLI-'-""-!.L!""'-"""--I VAN I AN 

Ochre 

Mountain 

limestone 

Woodman 

formation 

Upper 

Mississippian 

Great Blue 

limestone 

Devonian 

FIGURE 6.-Correlation of Carboniferous formations in an east·west bait from Eurekll, Nev., to the Cottonwood·PlI:t'k City area, Utah. 

40 GOLD HILL MINING DISTRICT, UTAH 

a small remnant of Lower Triassic limestone is found 

above the Gerster formation. In this place the thickness is about 600 feet. 

Age and correlation.-Four fossil collections from the 

Gerster formation have been referred by Mr. Girty to 

the Spiriferina pulchra zone of the Permian. His 

identifications are as follows: 

6061 and 6355. Half a mile west-northwest of benchmark 

5097 OIl Ibapah-Wendover road: 

Sponge. 

Clionolithus? sp. 

Eu reka,Nevada 


( Hague) 


Weber 


conglomerate 


Lower Coal 


Measures 


limestone 


Diamond 

Peak 

quartzite 

White Pine 

shale 

Devonian 

scale 

I

Fistulipora n. sp. 

Leioc1ema sp. 

(\> "" " 

~. 

~ 

Ely, Nevada 

(Spencer) 

Pennsylvanian 

Ely 

limestone 

sinman s ae 

Joana limestone 

pn 

Pennsylvanian 

BASE 

Upper 

Oquirrh 

formation 

Oquirrh 

formation 

CottonwoodPark City, Utah 

(Calkins· Boutwell) 

Pennsylvanian Pennsylvanian 

Triassic 

Park City formatIon 

Weber 

quartzite 

Limestone 

Cambrian 

Devonian 

Polypora sp. 

Derbya afr. D. multistriata. 

Chonetes n. sp. afr. C. geinitzianus. 

Productus longus. 

Pustula subhorrida var. rugatula? 

Strophalosia? sp. 

Strophalosia? n. sp. 

Spirifer pseudocameratus. 

Spiriferina pulchra. 

Spiriferina afr. S. kentuckyensis. 

Oquirrh Range, 


Utah (Gilluly) 


Productus multistriatus. 

Pustula nevadensis? 

Pustula nevadensis var. 

Pustula subhorrida. 

Pustula subhorrida var. 

Composita mira. 

Hustedia mormoni? 

Deltopecten n. sp. 

Deltopecten sp. 

Deltopecten sp. 

Pteria? sp. 

Gold Hill. 

Utah (Nolan) 

i 
CARBONIFEROUS SYSTEM 41 

6278. 3,000 feet west-northwest of benchmark 4984 on IbapahWendover road: 

Derbya afr. D. multistriata. Hustedia? sp. 

Pustula subhorrida? Deltopecten n. sp. 

Spiriferina pulchra. Bellcrophon? sp. 

Spiriferina afr. S. kentucky­ Euphemus? sp. 

ensis. 

6279. 1,500 feet south of 6278: 

Leioclema sp.. 

Domopora? sp. 

Chonetes n. sp. afr. C. geinitzianus. 

Productus multistriatus. 

Pustula nevadensis. 

i • 

of the Ely district, Nev.89 Rocks of this age appear 

to have been rather generally removed by erosion in 

the region west of the Wasatch Mountains. 

CORRELATION OF THE CARBONIFEROUS FORMATIONS 

Figures 6 and 7 summarize the correlations that have 

been made for the Carboniferous formations in the 

Gold Hill area. Figure 6 includes districts in an eastwest belt through Gold Hill, and figure 7 districts 

in a northeasterly belt, but the variations shown by 

the Carboniferous formations are quite unlike those 

shown by the pre-Carboniferous formations in the same 

belt (figs. 3 and 4). In the east-west belt, forexample, 

Gold Hill quadrangle, 


Utah (Nolan) 


Pioche district, 

Nevada(Westgate) 

Pennsylvanian Elephant 

limestone 

Oquirrh 

formation 

Bailey

Spring 

limestone 

alisman quartzi ?-----? _ _____7. ~tilnyOn 7-------+-------1 'or ml'lt ton . 

Upper ,.., 

Topache 

limestone 

Scotty Wash Mississippian ?.f------l. 

~"""q'='u';=ar""t=z:;clte~o=; ~. 

Devonian 

Lower 

Mississippian , Bristol Pass 

limestone 

Devonian Ochre 

Mountain 

limestone 

Devonian 

Upper 

Mississippian 

limestone 

Madison 

limestone 

Devonian 

Pustula subhorrida. 


Pustula subhorrida var. rugatula. 

Spiriferina pulchra. 

Composita mira. 

Acanthopecten? coloradoensis? 

FIGURE 7.-Correlation of Carboniferous formations In a northeast-southwest belt from Pioche, Nev., to the Randolph quadrangle, Utah. 

The SpiriJerina pulchra fauna is found in the Park 

City formation of the Wasatch Mountains 87 and the 

Phosphoria formation of southeastern Idaho.Ba A 

similar fauna was also found in the Arcturus limestone 

" Boutwell, J. M., Geology and ore deposits of the Park City district, Utah: U.S. 

Geol. Survey Prof. Paper 77, pp. 49-52, 1912. 

's Mansfield, G. R., Geography, geology, and mineral resources of part of south· 

eastern Idaho: U.S. Geol. Survey Prof. Paper 152, pp. 75-81, 1927. 

35311-35--4 

the thickness of the pre-Carboniferous formations increases rather regularly from east to west, whereas 

the Carboniferous forQlations show a pronounced thickening from the Cottonwood-Park City area to the 

Oquirrh Range, a thinning thence westward to Ely, 

and another thickening at Eureka. This change is 

"Spencer, A. c., Geology and ore deposits of the Ely district, Nev.: U.S. GeOl. 

Survey Prof. Paper 96, p. 28, 1917. . . 
42 GOLD HILL MINING DISTRICT, UTAH 

thought to be the result of the formation of a land area 

in western Nevada in late Paleozoic time about on the 

site of maximum sedimentation in pre-Carboniferous 

time, which resulted in the shifting of this area of 

maximum sedimentation eastward into Utah.oo 

The figure for the northeast belt of Carboniferous 

formations is also quite different from the corresponding figure for the pre-Carboniferous, owing in part to 

the substitution of the relatively easterly Frisco 

section for that of the House Range, which contains 

no Carboniferous beds, and in part to the incompleteness of the Pioche section. The thinness of the section 

in the Randolph quadrangle, however, suggests that 

if more complete data were available the regularity 

shown by the pre-Carboniferous formations in this 

zone would not be found. 

LOWER TRIASSIC LIMESTONES 

About 3,000 feet west of benchmark 4984 on Deep 

Creek, on the south side of the gulch, there is a small 

outcrop of brown-weathering limestone that contains 

numerous specimens of an ammonite related to 

Meekoceras. This outcrop is just west of the Gold 

Hill quadrangle. Its thickness is less than 50 feet. 

The contact of these limestones with the Gerster 

formation is concealed by gravel in the gulch, but the 

two are essentially conformable in strike and dip. In 

the report on the Park City district,91 to the east, the 

Triassic is stated to overlie the Permian conformably, 

although one of the cross sections given by Boutwell 

(B-B', pI. 27) shows an unconformity at this horizon. 

In the Frisco district no unconformity was recognized 

in the field, although it is suggested that one may be 

present.92 Mr. Girty has provided the following notes 

upon the fossils collected: 

This collection contains fossils of two types-small gastropods 

and large ammonites. Specimens are abundant but badly 

preserved. Very few of the gastropods show even the most 

general features of configuration. Some of them are apparently 

naticoid shells and suggest Natica lelia, but nothing more 

definite can be said of them. Of the ammonites also but little 

can be said save what is very general in character. Most if 

not all of them are discoidal in shape and more or less strongly 

evolute. Some have plicated sides; others are plain. Some have 

a narrowly rounded venter; others a venter truncated by a 

groove. The suture is shown by but few specimens and not 

completely and in detail by any of them. One shows the suture 

in detail but only in small part. The saddles are simple and 

rounded; the lobes fimbriated-evidently the suture is of the 

lJ.,leekoceras type. Inasmuch as a fairly complete knowledge of 

the suture is required for a close generic identification, even 

the best of these specimens cannot be classified generically, and 

it has seemed futile to attempt specific identifications. Of 

these specimens, however, it may fairly be said that most if 

not all of them are probably ammonites of the llJeekoceras 

" Nolan, T. B., A late Paleozoic positive area in Nevada: Am. lour. Sci., 5th ser" 

vol. 16. pp. 153-161. 1928. 

" Boutwell, J. M,. Geology and ore deposits of the Park City district, Utah: 

U,So GeoI. Survey Prof. Paper 77, pp. 51-52, 1912. 

n Butler, B. S., Geology and ore deposits of the San Francisco and adjaceut 

districts, Utah: U,S. Gool. Survey Prof. Paper SO, p. 37, 1913. 

group and that they probably represent several related genera 

or subgenera and an equal or larger number of species. This 

conclusion is closely connected with the stratigraphic occurrence 

of the fauna, with its utter unlikeness to the Permian fauna of 

the underlying beds, and with its close resemblance in type and 

preservation to the Lower Tria$sic faunas of this general region, 

which abound in shells of the Afeekoceras group, many of them 

closely resembling hi configuration the shells in this collection. 

UNCONFORMITY AT THE BASE OF THE EOCENE (1) 

Sedimentary rocks belonging to the Jurassic and 

Cretaceous periods were not found in the quadrangle, 

and the area was presumably being eroded during at 

least part of the time between the Triassic and the 

Tertiary. This erosion is shown by the unconformity 

between the Eocene (?) and older rocks. A conglomerate containing boulders of the older rocks is found 

at the base of the Eocene (?), and the conglomerate 

itself in various places rests upon the Triassic limestones, the Gerster formation, and the Oquirrh 

formation. 

TERTIARY SYSTEM 

WHITB SAGE FORMATION (EOCENE?) 

Distribution.-The deposit to which the name White 

Sage formation is herein applied is found only in the 

northwestern part of the quadrangle. Most of the 

outcrops are on one or the other side of Deep Creek 

between benchmarks 5120 and 4984. The two most 

extensive are those east of benchmarks 5045 and 5062. 

Another area underlain by the formation is found 

about a mile north of peak 6266; and still farther east 

there are two additional areas, both of them, however, 

being west of the road between Gold Hill and Ferber. 

The name is taken from '~llite Sage Flat, which is 

just west of the most southerly outcrop. 

Lithology.-The ,\Vhite Sage formation consists of a 

basal conglomerate of variable thickness overlain by 

fresh-water, rather impure limestones. The conglomerate ra.nges in thickness from 1 foot to more than 50 

feet. The included pebbles are mostly less than 6 inches 

in diameter. They are derived from Pennsylvanian and 

Permian sediments and are considerably less altered 

in appearance than thc bedded rocks of those formations now in place. Sand lenses are abundant in the 

conglomerate. 1-Iost of the exposures weather to a 

deep red and contrast strongly with the lighter-colored 

rocks beneath them. In some places thin layers of 

similar conglomerate are interbedded with the overlying limestone. 

The limestones arevery fine grained rocks which are 

generally brownish on fresh fracture but weather to a 

dead white or chalk color. Individual beds are a foot 

or more in thickness, and a few are as much as 6 feet 

thick. All the beds examined contain a rather large 

amount of extremely fine clay and varying amounts of 

quartz. In some beds grains of quartz or chert 1 millimeter or more in diameter are scattered throughout. 
TERTIARY SYSTEM 43 

A few beds contain thin brown-weathering chert stringers, and some beds show a characteristic wavy or 

concentric banding on weathered surfaces, not unlike 

some banding that has been attributed to algal action. 

About a mile west of benchmark 4984 on Deep 

Creek, beyond the limits of the quadrangle, beds of 

limestone belonging to the 'White Sage formation show 

noteworthy discordances in dip among themselves and 

with the conglomerate of the formation. It is thought 

that these may be the result of earth movements that 

were active during the time the beds were deposited. 

Thickness.-The original thickness of the Wnite Sage 

formation is not known, for it is everywhere unconformably overlain by lava or by recent gravel. The 

maximum thickness observed was in the isolated hill 

east of benchmark 5045 on Deep Creek, where about 

600 feet is present. 

Age and correlation.-Two collections of fossils were 

made from the "7hite Sage formation. These were 

reported upon by J. B. Reeside, Jr., as follows: 

TN-27 125. About 4,000 feet east-southeast of benchmark 

5045, Deep Creek: I have been unable, by chemical or mechanical means, to get anything but cross sections of the abundant 

gastropods in this lot. The genus Physa is represented by 

species very similar in form to those known in the Eocene of the 

region; and a high-spired species that probably belongs in the 

genus Goniobasis is also abundant and might well belong to one 

of several Eocene forms. These alone would not be sufficient 

for an age assignment, but the widespread occurrence of an 

identical fresh-water limestone in the Wasatch and Green River 

formations of central Utah, coupled with the fossils, makes it 

highly probable that the present material is also Eocene. 

TN··27 124. About 2,500 feet southeast of benchmark 5097 

on Deep Creek: This lot is smaller than the first, but it appears 

to contain the same fauna, and the same remarks apply to it. 

Eocene beds have been found in western or central 

Utah in only a few places, almost all some distance to 

the south and southeast of Gold Hill. About 125 miles 

to the east-southeast are rather extensive exposures 

of limestone underlain by conglomerate, which are referred to the Wasatch epoch of the Eocenc by Richardson 93 and Loughlin.94 These rest upon different Paleozoic and Mesozoic formations. A thick series of limestoncs with some conglomerate and sandstone beds in 

the Iron Springs district, 175 miles to the south, was 

mapped by Leith and Harder 95 as the Claron limestone, 

of Eocene age. It rests unconformably upon Cretaceous rocks with little discordance of dip. The nearest area in which rocks of supposed Eocene age have 

been recognized is near the north end of the Pilot 

Range, 75 miles north of Gold HilL Hague 96 has 

correlated these rocks with the Green River Eocene. 

These dip 450 E., but their relations to the underlying 

rocks are not described. 

"Richardson, G. B., Underground water in San Pete a.nd central Sevier Valleys, 

Utah: U.S. Geol. Survey Water·Supply Paper 199, p. 10, 1907. 

"Loughlin, G. F., Ore deposits of Utah: U.S. Geol. Survey Prof. Paper 111, 

pp. 326, 421, 1920. 

"Leith, C. K., and Harder, E. C., The iron ores of the Iron Springs district, 

southern Utah: U.S. Geoi. Survey Bull. 338, pp. 41-44, pI. 2, 1908. 

.. Hague, Arnold, U.S. Geol. Expl. 40th Par. Rept., vol. 2, p. 498,1877. 

There is no trustworthy evidence to indicate which 

if any of these three areas of Eocene rocks is equivalent 

to the White Sage formation. 

UNCONFORMITY ABOVE WHITE SAGE FORMATION 

The unconformity separating the White Sage formation from younger rocks, either volcanic rocks or 

gravel, is a pronounced stratigraphic break. The 

younger rocks are either horizontal or have low depositional dips, in contrast to dips as high as 55° in the 

"wte Sage formation. The volcanic rocks are the 

next younger of the rocks found in contact with the 

Eocene (1) beds, and the surface of contact is approximately as rough as that of the present topography. 

The significance of the unconformity is touched upon 

in the consideration of the age of the intrusions and of 

the major structural features (pp. 63-64). 

OLDER IGNEOUS ROCKS (EOCENE OR OLIGOCENE) 

GENERAL FEATURES 

About one-tenth of the quadrangle is underlain by 

a group of intrusive igneous rocks. By far the most 

extensive member of this group is a stock of quartz 

monzonite. Locally the stock has quartz dioritic or 

granitic facies, but these cannot be sharply differentiated from the quartz monzonite. 

Two groups of somewhat younger dike rocks, shown 

as porphyry dikes and aplites on plates 1 and 2, are 

associated with the stock. The porphyry dikes are 

generally dark gray and commonly contain conspicuous phenocrysts in a dense groundmass, but there 

are some varieties that are only slightly porphyritic. 

They show an almost complete gradation in composition from granite porphyries to basalts. The 

aplites are characterized by a pale-pink or white color, 

due to the almost complete absence of dark minerals, 

and an equigranular texture. Two varieties of aplites 

were recognized. 

QUARTZ MONZONITE 

Areal extent.-The quartz monzonite crops out as a 

stock in the east-central part of the quadrangle. The 

main body extends about 8 miles from north to south 

and about 4% miles from west to east within the quadrangle. Beyond the eastern border it is exposed at 

intervals for an additional 1% miles before disappearing 

beneath Lake Bonneville beds. The town of Gold 

Hill is near the northwest corner of this main body. 

Extending westward from the town and underlying 

most of the valley through which the Ferber Road 

passes is a wedge-shaped outcrop of the quartz monzonite about 3 Iniles long and about 1% !niles wide at 

its junction with the main body. Projections of the 

sedimentary rocks into the stock are numerous. 

South of Clifton, on Montezuma Peak, two such 

projections nearly divide the quartz monzonite into 

two separate bodies, and the outcrop of quartz monzonite on the ridge at the summit is only 300 feet wide . 
44 GOLD HILL MINING DISTRICT, UTAH 

There are also several areas of sediments, or "roof pendants", entirely enclosed within the quartz monzonite which further reduce its area of outcrop. Several 

small exposures of the intrusive that are without surface connection with the main body occur in the 

adjacent sedimentary rocks. The largest of these is 

at the head of Overland Canyon and has an area of 

about a quarter of a square mile. Smaller ones 

appear in Barney Reevey Gulch, in Hopkins Gulch 

below the Midas mine, and near the Ozark prospect. 

Many other smaller bodies have been mapped within 

the roof pendants or the projecting areas of sedimentary rocks. Outcrops of the quartz monzonite cover 

an aggregate area within the quadrangle of over 24 

square miles. 

In Dry and Sheep Canyons, in the Deep Creek 

Mountains, there are exposures of highly sheared and 

altered igneous rock that are probably to be correlated 

with the quartz monzonite. In both places the 

amount of such rock exposed is small. 

Petrographic and chemical character.-The unaltered 

quartz monzonite, though it all has the same general 

appearance, varies rather widely in both composition 

and texture from place to place. The greater part of 

the stock falls within the limits assigned to quartz 

monzonite by Lindgren,97 but locally specimens are 

found that have the composition of granite, granodiorite, or even quartz diorite. In a few places quartz 

is sufficiently scarce to permit the rock to be classified 

as a monzonite. Similarly, the bulk of the stock is 

nonporphyritic, but porphyritic facies are not uncommon. No sharp contact was found between any of 

these varieties, and the transition, whenever observed, 

was gradual in respect to either the proportion of the 

feldspars to each other or the number of phenocrysts 

present. 

The variety that is perhaps the most abundant and 

is also medial in character between various extremes 

may be considered typical .of the stock as a whole. 

This is a medium-grained rock, which assumes on 

weathered surfaces a purple-gray or brownish-gray 

color. Scattered through it are a few crystals of 

reddish orthoclase as much as 2 inches long. Smaller 

crystals of orthoclase are also present but are not as 

abundant as those of white plagioclase, which show 

fine twinning striae of!. their cleavage faces. The 

crystals of the two feldspars are generally larger than 

those of the other constituents. .Dark minerals make 

up about a quarter of the rock. Both hornblende and 

biotite are present, the former as greenish-black 

prisms with a good cleavage and the latter as small 

black hexagonal plates. Quartz is not readily apparent 

but on close examination may be recognized as small 

interstitial grains. 

Thin sections studied with the microscope show 

these minerals and in addition minor amounts of mag­

'7 Lindgren, Waldemar, Granodiorite and other intermedIate rocks: Am. Jour. 

Sci., 4th ser., vol. 9, p. 279, 1900. 

netite, titanite, apatite, and zircon. Plagioclase is the 

most abundant of the major constituents. In most 

specimens it is more or less strikingly zoned. The 

zoning is not progressive, although there is a general 

tendency for the more calcic zones to form the central 

portion of the crystal. The zones determined range 

in composition from a sodic oligoclase to a calcic 

labradorite. By far the bulk of the plagioclase is 

andesine, for the most part rather sodic. The potash 

feldspar is orthoclase and in most sections is perthitic. 

Quartz is interstitial to the other minerals. Hornblende in most specimens of this variety of rock 

is more abundant than biotite. It is notably pleochroic, ranging from a pale yellow-green to green. 

The biotite is also pleochroic from yellow-brown or 

greenish brown to deep brownish black. Locally it 

replaces hornblende but in most places it has euhedral 

outlines. Apatite is particularly abundant. The 

larger crystals show afaint purplish-gray pleochroism. 

The amount of titanite present is variable. Most of 

the crystals are irregular in outline and are associated 

with hornblende that has been altered to actinolite: 

It is probable that such titanite is secondary.. Much 

of the magnetite is also probably secondary, as it is 

largely localized in partly or wholly altered crystals of 

biotite and hornblende. In a few sections zircon 

crystals are included in biotite and are surrounded by. 

pleochroic haloes. 

The following chemical analysis, quoted from 

Butler,98 represents a specimen of this variety of quartz 

monzonite obtained west of the Western Utah Copper 

Co.'s Gold Hill mine: 

Analysis of quartz monzonite wellt of Gold Hill mine of Western 

Utah Copper Co, 

lB. O. Wells, analyst] 

Si0 __ _ ____________ 62.84 Ti0 ________________ _ 2 O. 42 

Al 0. 2 _______________ 14. 21 ZrO_____ "_________ _ Trace 

Fe2 03________________ _91 CO ________________ _ 2

FeO______________ __ 3.75 P20S2 ________________ _ .38 

_.41 MgO_ ____ _ ______ ____ 3.04 S___________________ _ .01 

CaO_________________ 4.72 MnO ______________ _ .06 

Na20_ __ _ _ _ _ _ __ _ _ __ _ _ 2. 85 BaO________________ _ .03 K2

0_________________ 4.60 

H 0- ____ _________ .26 99.72 

HzO+__ ___________ 1. 23 2 

The mineral composition calculated from the above 

analysis is as follows: 

Quartz _______________ 17.46 Biotite______________ _ 5. 58 

Orthoclase ___________ 23.35 Apatite_____________ _ 1.01 

calcite______________ _ Albitemolecule ______ 23.06 .30 

Anorthite molecule____ 8.90 

Hornblende___________ 19.21 98. 87 

In the calculation the relative proportions of hornblende and biotite were arbitrarily assumed, and an 

average of analyses of these minerals from similar 

rocks was assumed to represent their composition. 

After apportioning the oxides to the different minerals . 

.. Butler, B. S., Ore deposits of Utah: U.S. Geol. Survey Prot. Paper 111, p. 96, 

1919. 
TERTIARY 

there remained a small excess of FeO and a rather 

large one of H20+, which probably indicate that the 

specimen analyzed was partly sericitized. Specimens 

collected by the writer near the Gold Hill mine all 

showed this alteration more or less advanced. It is of 

some interest to note that both Fe20s and Ti02 are 

completely used up in the calculation of hornblende 

and biotite, leaving none for magnetite and titanite. 

This is in accord with the observation that the magnetite and titanite, as observed in the sections, are 

more or less restricted to large crystals of hornblende 

and biotite and in some places at least have been 

formed at their expense. 

An examination of specimens taken from the wedgeshaped area of the intrusive south of Dutch Mountain 

indicates that they are close to the dividing line 

between granite and quartz monzonite. Biotite is 

more abundant than hornblende, and the plagioclase 

is slightly more sodie and is apparently a calcic oligoclase, although rather thorough sericitization in the 

slides examined prevented accurate measurement. 

There are no other di.fferences from the more common 

variety. 

At the other extreme is a specimen taken from the 

I11J1in body of the intrusive near the east border of the 

quadrangle, in which the content of orthoclase has 

decreased to 10 or 15 percent. This rock is without 

'the large phenocrysts of orthoclase and has a larger 

proportion of darker minerals. The ratio of the 

feldspars places the rock in the group of granodiorites. 

A similar rock is found as a dike cutting the Ochre 

Mountain limestone a few hundred feet north of the 

Overland Road half a mile southeast of the junction 

of roads from Ibapah and Gold Hill. The quartz 

content of this rock is rather less than normal but is 

large enough for the rock to be classed as a granodiorite. 

The quartz monzonite is porphyritic in places, 

particularly at its contacts, with phenocrysts of both 

orthoclase and plagioclase. In this variety there are 

all gradations in size between the phenocrysts and the 

crystals of the same minerals in the groundmass. 

The smaller grains are of about the same size as that 

in the nonporphyritic rock. Such a facies may be 

classed as porphyritic quartz monzonite. 

The porphyritic habit is particularly pronounced in 

the exposures of the intrusive south and southwest of 

Dutch Mountain and west of Gold Hill. Thin sections 

of specimens from this region show that there is 

apparently a gradation between the porphyritic quartz 

monzonite and rock that is more properly termed 

quartz monzonite porphyry. In the latter variety 

the phenocrysts of quartz, feldspars, and the dark 

minerals may be several millimeters long, but the 

crystals in the groundmass are only a fraction of a 

millimeter in diameter and are for the most part of 

quartz and feldspar, chiefly orthoclase. In texture 

and composition these rocks are not unlike some of 

SYSTEM 45 

the lighter-colored porphyry dikes that cut the main 

mass of the intrusive to the east. 

Darker nodules or basic segregations are found scattered throughout the normal quartz monzonite. 

They range from an inch to a foot in diameter and may 

be much more abundant in. one place than another. 

The nodules are characterized by a concentration of 

hornblende, a diminution of feldspars, and an absence 

of quartz and biotite. A thin section of one of them 

shows a large amount of euhedral magnetite, some 

titanite, apatite, and much green hornblende, similar 

to that of the quartz monzonites. Andesine and 

orthoclase are present in about equal amounts and 

are later than the hornblende, which is frayed and 

embayed by them. 

Another kind of inclusion, usually of dark color, 

which is found near the contacts of the quartz monzonite, is metamorphosed sedimentary rock. These are 

fine-grained to dense and are commonly less than 2 or 3 

inches in maximum diameter. They are not so uniform in texture and appearance as the basic segregations and furthermore show a border of different color 

and texture at the contact with the normal quartz 

monzonite. Thin sections show a mineral composition 

quite unlike that of the segregations, and different 

specimens differ from one another. One specimen 

obtained near Gold Hill, for example, showed a finegrained aggregate of quartz, plagioclase, biotite, magnetite, and a green isotropic mineral that is probably 

pleonaste, the magnesia-iron spinel. The inclusion is 

separated from the normal igneous rock by a border of 

sericite. The restriction of such inclusions to the 

contact, their mineral composition, and the presence 

of borders or "reaction rims" of different composition 

indicate that they are highly altered fragments from 

the Oquirrh formation that have been engulfed in the 

igneous rock during its intrusion. 

Factors influencing the localization oj the quartz 

monzonite.-Preexistent faults appear to have played 

an important part in determining the location of the 

quartz monzonite stock. The influence in a minor 

way of such older faults is extremely well shown in 

several places on the south side of Montezuma Peak, 

where the quartz monzonite contact follows faults that 

must have existed prior to the intrusion. In these 

places the quartz monzonite apparently utilized the 

old fracture lines as a means of ingress but caused no 

additional deformation. 

A more definite relation between old faults and the 

intrusion is suggested by the essentially complete 

restriction of the intrusion between two large transverse faults, the Blood Canyon fault on the south and 

the Pool Canyon fault on the north. These two faults 

are thought to limit also an extensive thrust fault. 

In view of the dependence of the intrusion upon 

preexistent faults noted in the preceding paragraph, it 

seems probable that there may be a similar relation 
46 GOLD HILL MINING DISTRICT, UTAH 

between these major faults and the intrusive body. 

The thrust fault limited by the transverse faults must 

have caused a high degree of fracturing in the affected 

rocks, and this in turn provided the necessary lines of 

weakness that were apparently required for the emplacement of the stock. 

This suggestion implies that the intrusion came into 

place without causing any great deformation of the 

invaded rocks, and the implication is confirmed by 

the absence of any discernible doming in the sedimentary rocks bordering the stock. The only evidence 

that there were any pronounced "'arth movements 

during the intrusion of the quartz monzonite is found 

along the western border of the main mass of the 

intrusive, where there are several faults of large throw. 

For several reasons (sec p. 89) these faults are considered to have been caused by the intrusion and to 

mark the location of the primary channel through 

which the quartz monzonite was intruded. 

PORPHYRY DIKES 

Distribution and size.-Porphyry dikes are rather 

widely distributed throughout the quartz monzonite 

area and also over much of Dutch Mountain. They 

are most abundant in the region about 2 Iniles east of 

Clifton, where an area of nearly a square mile is more 

than half underlain by porphyries. 

The ratio between the length and breadth of the 

dikes is rather variable. The quartz monzonite porphyry dike cutting through the claims of the Western 

Utah Copper Co. at Gold Hill, for example, may be 

traced for nearly 2 miles and for the greater part of 

this distance is less titan 20 feet wide. Some other 

dikes that were 10 feet or less in width were followed 

for distances close to half a mile. On the other hand, 

several of the dikes in the locality east of Clifton are 

250 feet or more wide and are less than half a mile 

long. A similar rather thick lens occurs on the north 

side of Dutch Mountain half a mile south of the Garrison Monster mine, and another just north of the town 

of Gold Hill. In several places dikes less than a foot 

wide could not be traced beyond the rock outcrop in 

which they were found. 

Appearance.-As these dikes have a considerable 

range in composition, it is not surprising that there 

is a corresponding variation in their appearance. Two 

general varieties may be distinguished. One is a highly 

porphyritic rock, whose prevailing color is a greenish 

or pinkish gray, or even white in places where alteration has been especially intense. The phenocrysts consist chiefly of rounded quartz crystals and dull feldspars, '\vith locally some of ferromagnesian minerals, 

particularly biotite. The groundmass is invariably too 

fine-grained for any of its constituent minerals to be 

recognized. 

The other variety has characteristically a dark 

greenish-gray color, that contrasts strongly with the 

lighter color of the quartz monzonite. Its phenocrysts are commonly neither abundant nor conspicuous 

and are for the most part of the ferromagnesian minerals, but in several specimens they are similar in 

numbers and in character to those in the lightercolored rocks. Locally also, particularly east of Clifton, scattered phenocrysts as much as an inch in length 

may be found. In some of the rocks rounded quartz 

phenocrysts about an eighth of an inch in diameter 

are present in small quantities and are conspicuous 

because of the dark color of the rest of the rock. The 

matrix in this variety also is much too fine-grained to 

be determinable megascopically. 

Only one equigranular dike was noted during the 

field work. This was the thick dike south of the Garrison Monster mine. It has a pepper-and-salt appearance due to the presence in nearly equal quantities 

of dark-greenish hornblende and other dark minerals 

and white feldspathic minerals. Some of the hornblende is in the form of needles or poorly defined platy 

aggregates nearly a quarter of an inch long, but they 

are not sufficiently distinct to give the rock a porphyritic aspect. 

Microscopic features.-Two varieties of the porphyry dikes may be distinguished on the basis of their 

composition and texture as diselosed by microscopic 

examination. These two varieties correspond roughly 

with the two megascopic divisions, in that the lightercolored dikes contain a higher proportion of quartz 

and feldspars and their groundmass has an allotriomorphic texture, whereas the darker dikes contain a 

higher proportion of dark minerals and their groundmass includes laths of plagioclase, whose relations to 

the oth~r minerals in the groundmass are characteristic of what has been named an "intergranular" texture. Several specimens, however, appear to bridge 

the gap between the two extremes of composition and 

texture, and the distinction between them is chieffy 

valuable for purposes of description. 

The dikes characterized by predominance of the 

light-colored minerals and allotriomorphic texture of 

the groundmass contain phenocrysts of quartz, orthoclase, plagioclase, biotite, and rarely hornblende, in a 

groundmass of the same minerals. The quartz phenocrysts are strikingly corroded and embayed by the 

•groundmass. 	 In many places the tabular feldspars 

are too altered for satisfactory determination, even 

where those in the surrounding quartz monzonite are 

relatively fresh. "'bere they can be identified, however, it is generally possible to prove that both orthoclase and plagioclase are present; the composition of 

the plagioclase ranges in different dikes from albite to 

andesine. Biotite in small quantities is a common 

constituent and occurs as hexagonal prisms that are 

about a sixteenth of an inch across, from a half to a 

quarter of the diameter of the phenocrysts of quartz 

and feldspar. Hornblende is an uncommon phenocryst in the more siliceous rocks. The groundmass is 

composed of a very fine grained aggregate of quartz, 

-
TERTIARY SYSTEM 47 

feldspar, and, locally, shreds of biotite, although in 

many specimens it is so thoroughly altered that the 

original composition is uncertain. The minerals in the 

groundmass, unlike the phenocrysts, do not show crystal outlines, and the resultant xenomorphic texture is 

markedly different from that shown by the groundmass 

of many of the darker dike rocks. 

In this variety the proportions of quartz and the 

two kinds of feldspars vary greatly in different dikes. 

The dike that forms the footwall of the Cyclone vein, 

for example, is a granite porphyry. On the other 

hand, a dike in Tribune Gulch, on the southeast side 

of Dutch Mountain, is close to a diorite porphyry. 

Between these two extremes are dikes that contain 

more or less quartz and both orthoclase and plagioclase 

and are classified as quartz monzonite porphyries, of 

which the prominent dike that cuts through Gold Hill 

is an example. 

The porphyry dikes of the second variety contain 

phenocrysts of augite, hornblende, biotite, plagioclase, 

and quartz. Augite is abundant in a few of the dikes 

but in several is partly altered to green hornblende. 

The hornblende, generally accompanied by biotite, 

also occurs in some of the dikes that contain no augite. 

The phenocrysts of these dark minerals are generally 

from a sixteenth to an eighth of an inch in diameter, 

but in a few places phenocrysts of augite as much as 

an inch in length have been noted. The plagioclase 

phenocrysts may be as much as half an inch in diameter 

but are generally a quarter of an inch or less and have 

a composition ranging from sodic andesine to sodic 

labradorite. Corroded and embayed quartz phenocrysts are found sparingly in almost all the dikes. The 

most abundant mineral in the groundmass is microscopic plagioclase, which, where determinable, is somewhat more sodic than that of the phenocrysts. It has 

a striking tabular habit. The laths, however, do not 

show a uniform orientation but are haphazard or, 

locally, in the form of rosettes. Between the laths are 

tiny grains of augite (in dikes that contain augite 

phenocrysts), hornblende, biotite, and locally quartz 

and orthoclase. This texture is similar to that called 

intergranular in basalts and andesites, and many of 

these dikes may be accurately termed augite or hornblende andesite or basalt. 

There is a considerable variation in composition in 

the rocks of this variety, as in the lighter-colored dikes. 

All the dikes in this group, however, show the intergranular texture of the groundmass. Some of them 

contain sufficient quartz to be called dacites, and others 

are clearly basaltic. 

Several dikes were found that have in part the 

characteristics of the first variety and in part those of 

the second variety. These rocks commonly contain 

phenocrysts of quartz, orthoclase, plagioclase (oligoclase or andesine), and locally biotite, but phenocrysts 

of hornblende or augite are either scarce or completely 

absent, the rocks thus resembling the more siliceous, 

light-colored dikes. The groundmass of such rocks is 

largely made up of laths of plagioclase, and the intergranular texture thus formed is similar to that of the 

darker-colored dikes. A dike of this class that crops 

out just east of the old Garrison Monster camp has a 

groundmass in part xenomorphic and in part composed 

of radiating laths of plagioclase, similar in appearance 

to those found in rocks whose groundmass is wholly 

intergranular. 

Several of the porphyry dike rocks show a local 

development of granophyric texture in the groundmass. 

This microscopic intergrowth of quartz and feldspar 

was found chiefly in the lighter-colored siliceous dikes, 

but it is also present in the nearly equigranular thick 

dike south of the Garrison Monster mine. Its significance in these dikes is not understood, but the conditions favoring its development were evidently nearly 

independent of the composition of the dike. 

All the dikes are more or less altered, and almost 

invariably the degree of alteration in the dikes intrusive into the stock is greater than that of the surrounding quartz monzonite. Sericite, calcite, chlorite, and 

quartz are the chief secondary minerals, as they are in 

most of the altered quartz monzonite. 

Relations to other rocks.-The porphyry dikes intrude 

both the quartz monzonite and the sedimentary rocks 

and are in many places localized along minor faults. 

At least two of the dikes in the quartz monzonite 

differ from those in the sediments in that they are 

discontinuous. One of these dikes is on the east side 

of the northward-draining gulch east of the summit of 

Gold Hill, and the other is about a quarter of a mile 

east of the Success mine. The exposures of the second 

dike show clearly that the discontinuity is not the 

result of later faulting but is an original feature. 

Preexistent joint planes or fractures in the quartz 

monzonite appear to have played an important part in 

the determination of the course of the dike, and where 

they were not sufficiently well developed, the dike did 

not enter. 

In several places on the southeast side of Dutch 

~fountain aplite dikes are in contact wi.th the porphyry 

dikes, and in all such occurrences the aplites are ,found 

to be younger. Quartz-sulphide veins are also younger 

than the dikes, as is shown by the developments at 

the Cyclone mine and elsewhere. In the locality east 

of Clifton the dikes are cut by several carbonate veins, 

which are thought to represent the latest of the series 

of events initiated by the intrusion of the quartz 

monzonite. 

Relations oj the porphyry dikes to one another.-In 

a few places different varieties of the porphyry dikes 

are in contact with each other, by reason of the formation of compound dikes. Examples of such dikes are 

found about 2,000 feet west of the Western Utah mine 

and also in the area of dike concentration east of 
48 GOLD HILL MINING DISTRICT, UTAH 

Clifton. At both localities the lighter-colored more 

siliceous dikes are younger than the darker one~. On 

the eastern slope of hill 5675, near the mouth of 

Rodenhouse Wash, however, a light-colored quartz 

monzonite porphyry is clearly cut by a more basic 

dike, which strikes nearly at right angles to it. It 

appears, therefore, that although the lighter-colored 

dikes are in general younger, there are local exceptions 

to the rule. 

APLITE DIKES 

. Distribution a:uJ. character.-Two varieties of aplite 

d~ke~ may be .dlstmgv.ished. One of these is a palepmkish to white rock that occurs as small lenticular 

or cylindrical masses in the quartz monzonite. Its 

boundaries with the main intrusive are gradational 

there being a zone between the two in which a coarsen~ ing of the grain and an increase in dark minerals from 

the aplite to the quartz monzonite may be discerned. 

Almost all the occurrences of aplite of this kind may 

be measured in inches or feet; a few extend for 10 feet 

or so i and exceptionally some of the cylindrical masses 

may have a diameter of 30 or 40 feet. This variety 

of aplite is widely distributed throughout the main 

outcrop of the quartz monzonite stock, but because 

of the small size of the individual bodies they are not 

shown on the geologic map. 

The second variety of aplite is limited to the quartz 

monzonite area on the southeast side of Dutch Mountain north and northwest of the town of Gold HilL 

Thes~ dikes are shown on the geologic map. They 

are lIght-colored rocks that are generally more resistant to erosion than the surrounding rocks and can be 

re~dily traced by reason of their color and superior 

r~hef. Most of the exposures are relatively narrow 

dIkes that are only exceptionally wider than 20 feet 

and are generally only 10 feet or less. Several of them 

have been traced for at least 2,000 feet. A few of the 

outcrops, notably one about three-quarters of a mile 

northwest of the town of Gold Hill, have a bulbous 

outline, from which thin dikes extend for some distance. 

Quartz and feldspar make up almost all of this 

variety of aplite, and many of the feldspar crystals 

have a tabular habit. Crystals of biotite can be distinguished in several of the dikes but are absent in 

others. Tiny irregular splotches of blue tourmaline 

are also present in some specimens. 

Microscopic features.-The minerals found in the 

first variety of aplite are quartz, calcic oligoclase 

perthitic orthoclase, rare biotite, and the accessorie~ a~atit?, titanite, zircon, and iron ores. They do not 

dIffer m any respect from the same minerals found in 

the quartz monzonite-in fact, the only differences 

from the main intrusive shown by this variety of aplite 

are the slightly smaller grain size and the nearly complete absence of the dark minerals. 

The second variety of aplite is much finer grained 

than the first, individual crystals having an average 

diameter of 1· to 2 millimeters. N early equal quantities of quartz, perthitic orthoclase, and calcic oligoclase make up almost the entire rock. Zircon is present as an accessory mineral, but apatite titanite and . ' , lron ores are almost completely absent. In some specimens biotite is present in small crystals. The texture 

of the rock' is panidiomorphic in that many of the 

~eldsp~r grains are euhedral, with quartz filling the 

mterstIces. Where tourmaline is present it replaces 

the other constituents in irregular splotches. Its pleochroism in thin section is w = deep greenish blue, 

E = pale yellow-green. 

Relations to other rocks.-The aplite dikes were not 

recognized. as cutting sedimentary rocks and are apparently restncted to the quartz monzonite. Those of the 

s~cond variety. are clearly younger than the porphyry 

dikes exposed m that area, and the aplites of the first 

variety have been noted in the wall rocks of some of 

the quartz sulphide veins. If the two varieties are of 

the same age, the combined evidence would make 

them later than the period of porphyry dike intrusion 

and earlier than much of the ore deposition. The 

difference in habit and occurrence of the two varieties 

however, makes any assumption of contemporaneit; 

between them rather doubtfuL 

AGE OF THE OLDER IGNEOUS ROCKS 

Although the White Sage formation, of Eocene (?) 

age, is not itself intruded by either the quartz monzonite or the dike rocks within the quadrangle, it is 

locally metamorphosed and is therefore believed to be 

older than the intrusive. This conclusion is checked 

by the structural history of the quadrangle. (See 

p. 64.) On the other hand, volcanic rocks thought 

to be of late Pliocene age overlie the quartz monzonite 

unconformably. The emplacement of the stock must 

therefore have occurred at some time between these 

two epochs. As a long period of erosion must have 

been required to expose the quartz monzonite before 

the volcanic rocks could be deposited upon it, it would 

appear that the intrusion probably took place between 

the late Eocene and early Oligocene. 

In other parts of Utah similar igneous rocks have 

been reported to be either of late Cretaceous or early 

Eocene age 9\l o!" of late Eocene or post-Eocene age.l 

The Gold Hill intrusion must be of the latter age. 

PLIOCENE (?) SEDIMENTS 

About a mile west-southwest of Ibapah, on the west 

ed~e of the quadrangle, a small area is covered by a 

serIes of marl, sandstone, and gravel. These materials 

are exposed much more extensively to the west. 

The beds have a white or light brownish-gray color 

that contrasts with the darker color of the younger 

" Oilluly, James, Basin Range faulting along the Oquirrh Range, Utah: 0001. 

Boc. America Bull., vol. 39, pp. 1117-1118, 1928. 

I Loughlin, O. F., Oeology and ore deposits of the Tintic mining district, UI.ah: 

U.S. Oeol. BUJ'vey Prof. Paper 107, p. 104, 1919. 
TERTIARY 

gravel nearby. The most common rock is a coarse 

grit or sandstone, fairly well cemented by calcium 

carbonate. Locally these pass into beds containing 

pebbles that must have come from the west or south, 

as shown by bedrock exposures in those directions. 

The grits are composed chiefly of quartz grains, but 

there are also numerous flakes of biotite. Some of 

the grits are perceptibly cross-bedded. 

A few beds of marl are included. These are 2 or 3 

feet thick and are more resistant to weathering than 

the other members of the series. They are filled with 

casts of tiny tubes, which may represent plant rootlets 

or stems. A few grains of quartz 1 or 2 millimeters in 

maximum diameter can usually be found within the 

marl. 

About 100 feet of these beds is exposed within the 

quadrangle, but the total thickness exposed to the 

west is much larger. 

No diagnostic fossils were found in these rocks. A 

few fragments of bones were found and submitted to 

Dr. J. W. Gidley, of the United States National 

Museum, but the material was too poor to be identified even generically. The beds are essentially flatlying but are well dissected and overlain in some 

places by gravel containing pebbles of volcanic rocks. 

They are therefore thought to be of prevolcanic age, 

and, as they are not disturbed, of post-Eocene age. 

It is thought that they were deposited shortly before 

the volcanic rocks were erupted, alld because of this 

belief they have been assigned tentatively to the 

Pliocene. 

YOUNGER IGNEOUS ROCKS (LATE PLIOCENE?) 

At several places in the quadrangle there are smaH 

areas covered by igneous rocks whose relations make 

them easily recognized as being much younger than 

the Gold Hill stock and its associated dikes. The 

greater number of these outcrops are either lavas or 

pyroclastic rocks but in several places small intrusive 

bodies were found. The composition ranges from 

rhyolite to basalt, with rocks of intermediate composition and rich in potassium greatly predominating. 

Because of the small size of most of the outcrops of 

these rocks, and because of the impossibility of establishing the correct chronologic sequence between such 

isolated occurrences, the whole group is shown on the 

map under the same symbol. 

DISTRIBUTION AND RELATIONS 

The bulk of the volcanic rocks are found in the 

northwestern part of the quadrangle, particularly on 

both sides of Deep Creek. In the canyon of Deep 

Creek itself from benchmark 5045 south there are five 

small necks, and to the east and west flows and pyroclastic rocks occur. The largest area covered by the 

volcanic rocks within the quadrangle is that about 2 

Iniles east of Deep Creek on the western and southern 

SYSTEM 49 

slopes of peak 6147. There are also some fair-sized 

exposures in the area of low relief between the Ferber 

Road and the wagon road between the Erickson ranch 

and Gold Hill. These are chiefly lavas but include 

some tuffaceous rocks. 

These volcanic rocks were erupted before the cutting of the present Deep Creek Valley, as is shown by 

the lack of outcrops other than necks in the flatbottomed portion of the valley, and by the restriction 

of the flows to mature valleys in the higher land on 

each side. The recent cutting of the lateral gulches 

east and west of benchmark 5062 on Deep Creek has 

exhibited small hanging valleys filled by the lavas. 

The pyroclastic rocks appear to have been erupted 

first, for they are overlain by lavas or cut by necks 

wherever observed. Erosion was active during the 

extrusion of the lavas in this region, for a widespread 

flow of hypersthene-augite latite rests unconformably 

upon the other lavas and locally lies directly upon the 

filling of the necks through which these older flows 

were erupted. 

Small exposures are found at a number of places in 

the south-central and southeastern parts of the area. 

There are several patches on the Lincoln Highway 

south of Gold Hill and similar occurrences on the 

northern and northeastern parts of Clifton Flat. 

These are chiefly lavas. In Rodenhouse Wash about 

1Yz miles north of Clifton a small area is covered by 

both lavas and pyroclastic rocks. An exposure of 

moderate size was found in Blood Canyon, and smaller 

residual patches are present here and there along the 

lower part of Overland Canyon and among the Lake 

Bonneville deposits through which the stream has cut. 

The volcanic rocks in these more easterly localities 

commonly occur in valleys cut in the quartz monzonite 

or in the sedimentary rocks intruded by it. Their 

eruption appears to have been more or less contemporaneous with the deposition of the gravel that fills 

some of the valleys in this region. At the mouth of 

North Pass Canyon, for example, a dike of alkali 

basalt is exposed within the gravel and is thought to 

be younger, for otherwise it would be necessary to 

believe that the dike must have stood as a narrow wall 

over 20 feet high while coarse gravel was being deposited around it-a view that is difficult to accept, 

because the dike is much less resistant to weathering 

than the Pennsylvanian rocks that would have originally formed its walls. Some of the outcrops of lava 

in Blood Canyon also appear to be younger than the 

gravel. On the other hand, many of the exposures of 

volcanic rocks in this region are overlain by gravel, 

which is now being eroded. 

PETROGRAPHY 

The younger volcanic rocks have a considerable 

diversity in composition, the silica in the five specimens 

analyzed ranging from 47.36 to 70.30 percent. Rocks 
50 GOLD HILL MINING 

containing about 60 percent of silica are by far the most 

abundant. In the field, and even in the microscopic 

study of the lavas, the rocks appear to represent a normal series of basalts, andesites, and rhyolites. The 

chemical analyses, however, show that they are all rich 

in potassium and that the series includes alkali basalts, 

latites, trachytes, and rhyolites. 

The abundance of such potassium-rich volcanic rocks 

in Utah and New Mexico has been noted and commented upon by Butler 2 and ·by Lindgren, Graton, 

and Gordon.3 

Biotite and hornblende andesites or latites.-By far 

the most abundant volcanic rocks in the quadrangle 

are biotite and hornblende andesites or latites. Most 

of the flows and necks found on both sides of Deep 

Creek are of this composition, as are those in Blood 

Canyon and in Clifton Flat. These are all porphyritic 

rocks that commonly weather to shades of brownish 

gray but are greenish to purplish gray on fresh fracture. 

Plagioclase, biotite, hornblende, and augite are the 

only abundant phenocrysts and are embedded in a 

groundmass that may be almost entirely glassy in 

many of the flows or nearly holocrystalline in some 

specimens from the necks. All the rocks show some 

alteration, but this is most marked in the necks, which 

are in places so affected that only traces of the original 

minerals remain. 

The zoned plagioclase phenocrysts range in composition from sodic andesines to calcic labradorite. 

The more calcic varieties particularly contain numerous glass inclusions. In most of the specimens either 

hornblende or biotite is the dominant dark mineral, 

but in one specimen from Blood Canyon the two are 

present in nearly equal amounts. They are commonly 

bordered by thick rims of magnetite. Both green and 

brown hornblende were recognized, but the former 

appears to be limited to varieties in which biotite is 

abundant. Sparse phenocrysts of augite are present 

in both the biotite-rich and hornblende-rich lavas and 

sporadic crystals of quartz are even less common. 

Apatite and, in one specimen, titanite are accessories. 

The groundmass of these rocks is commonly composed of glass in which are embedded tiny laths of 

plagioclase and dots of magnetite. The plagioclase 

laths appear to be somewhat less calcic than the 

phenocrysts, most of those determined being sodic to 

medium andesines. Trichites and globulites were 

found in the glass in some specimens, and perlitic 

cracks are also present. Both the color of the glass 

and its index of refraction are different in different 

rocks, the index ranging from less than 1.50 to slightly 

less than that of balsam. In many specimens, particularly those from the necks, the glass has been devitrified, and poorly defined areas of quartz and feldspar 

replace it. In several of the glassy flows oriented 

I Butler, B. S., Ore depositsofUtsh: U.S. Geol. Survey Prof. Paper 111, p. 89,1920 • 

• Lindgren, Waldemar, Graton, L. C., and Gordon, C. H., Ore deposits of New 

Mexico: U.S. Gool. Survey Prof. Paper 68, pp. 43-44, 1910. 

DISTRICT, UTAH 

plagioclase laths are distributed in wavy bands that 

are locally interrupted by and in part flow around 

nodules containing much glass. 

An analysis of a specimen of this group of lavas 

collected west of benchmark 5030 on Deep Creek gave 

the following result: 

Analysis of biotite-augite lalite 

[ J. G. Fairchild, analyst] 

SiOz__ ---­ 57.94 K 2 

0 _____________ _ 8.90 

Alz0 3 _____ -­ ____ -­ __ 16.66 TiO z

________ _ ___ _ l. 00 

Fe203______ -- FeO ____________ _ 

MgO _____ _ 

CaO_____________ _ 

2.73 

.57 

.60 

4.91 

P20.____ _______ _ 

H20+ ______ _ 

HzO­ ___ _ 

.11 

l. 66 

3. 82 

NazO _____ -­ --­ -­ 1. 29 100. 19 

I (II)."5.2."2, vulsinose. 

The high content of K20 was totally unexpected, for 

the microscopic examination had indicated no potashbearing mineral except a relatively minor amount of 

biotite. A comparison of the norm of the rocIe with 

the mode makes it evident that the glassy groundmass 

must consist almost entirely of potash feldspar with a 

small amount of quartz. The propriety of terming 

this rock a latite may perhaps be questioned, but the 

relatively low silica and alumina and relatively high 

lime made it seem preferable to use this name rather 

than trachyte, in spite of the preponderance of potash 

over soda. The rock is somewhat similar in chemical 

composition to a trachyte from the Iron Springs district 

described by Leith and Harder 4 but is higher in lime 

and lower in silica. 

No other analyses were made of members of this 

group of rocks, and their reference to "andesites or 

latites" reflects the uncertainty as to their true nature 

that results from the lack of additional analyses. 

Hypersthene-augite latite.-Rocks of the composition 

of hypersthene-augite latite are exposed in many 

localities in the northwestern part of the area from the 

western slopes of Dutch Mountain to the western 

border of the quadrangle. All these exposures appear 

to be a part of the same flow or of closely related flows, 

as they all have the same relations to the other volcanic 

rocks. Only one vent through which these rocks 

could have reached the surface was found. This is 

a small elliptical neck about 2,500 feet north-northwest 

of benchmark 5062 on Deep Creek. 

In hand specimens the rock is dark gray to grayish 

black. Phenocrysts of yellowish or white plagioclase 

and greenish-black pyroxene are abundant and make 

up one-third to one-half of the rock. The groundmass 

is dense blnck and in some places has a conchoidal 

fracture. Locally there are tiny vesicles, which may 

be filled with a chloritic mineral, but these are not 

abundant. 

Thin sections show that the abundant plagioclase 

phenocrysts have an average composition of Ab4oAn~~. 

• Leith, C. K., and Harder, E. C., The iron ores of the Iron Springs dlstrict4 

southern Utah: U.S. Geol. Survey Bull. 338, p. 58, 1008. 
_____________ _ 

TERTIARY 

They commonly show an oscillatory zoning, however, 

and portions may' be as sodic as Ab6oAn4o or as calcic 

as Ab25An75' Glass inclusions are present locally. 

Hypersthene and augite phenocrysts are found in 

about equal amount. The hypersthene is pleochroic 

in shades of light reddish brown and greenish gray. 

Sparse phenocrysts 'of brown hornblende were recognized in a few specimens. Magnetite and apatite are 

accessory minerals. In several of the specimens the 

groundmass is composed entirely of brown glass, 

which locally showed perlitic cracks, trichites, and 

globulites. Other specimens show numerous labradorite laths in the groundmass and, with increasing 

crystallinity, small pyroxene crystals. I~ the latter 

specimens the texture is typically hyalopilitic. 

A specimen of this rock taken a quarter of a mile 

west of benchmark 5045 on Deep Creek was analyzed 

with the following results: 

Analysis of hypersthene-augite latile 

[J. G. Fairchild, analyst] 

KzO _______ . _ 3. 02 

A120 a________ ------- 15.25 

SiOz__ ---------- 61. 52 

TiOz_______ -------- 1. 00 

Fe20a-- ------------ 2.20 PzOa___ • ___ ---- - -- .16

FeO ______________ _ 3.97 HzO+ _____ _ 2. 23 MgO______________ _ 2.59 HzO- ______ -­ .36 

CaO ________________ _ 5. 72 N~O 2.31 100.33 

flIlA.3.3, harzose. 

The analysis shows that the rock falls into the latite 

group. It is rather similar to a latite from the Tintic 

district described by Loughlin,s which also is hypersthene-bearing. In the Rosenbusch classification a 

volcanic rock of this composition would be termed a 

trachyandesite. A rock of this name from Col d'Oreccia, Corsica, is chemically similar.6 

The norm was calculated from the analysis and 

compared with a mode roughly estimated by the 

Rosiwal method. The result indicated that the glassy 

base, if it were crystalline, would be composed of 

about 2 parts of quartz, 2 of orthoclase, and 1 of sodic 

andesine. 

Trachyte.-Just east of the small knob in the gulch 

east of benchmark 5120 on Deep Creek there is a 

small area of rock which is notably different in appearance from the latite lavas. This is a light-pink rock, 

locally splotched by pale-green areas. Small laths of 

feldspar are scattered through the rock, and there are 

a very few crystals of black hornblende. A thin section 

shows that about a third of the rock is composed of 

phenocrysts, chiefly albite-oligoclase, with much less 

abundant sanidine. Green hornblende and augite are 

of minor importance. Apatite needles, magnetite, and 

zircon were identified as accessory minerals. The 

'Loughlin, G. F., Geology and ore deposits of the Tintic mining district, Utah: 

U.S. Oeol. Survey ·Prof. Paper 107, p. 62, 1919. 

• Rosenbusch, Harry, Elemente der Gesteinslehrei 4th ed., by A. Osann, p. 416, 

Stuttgart, 1923. 

SYSTEM 51 

remalmng two-thirds of the rock was originally of 

glass, but much of it, together with almost all of the 

augite crystals, has been replaced by calcite. In a 

few places there are areas of a colorless, almost isotropic chloritic mineral fringed with calcite. A partin.! 

analysis of this rock gave the following result: 

Partial analysis of trachyte 

[J. G. Fairchild, analyst] 

Si02 _ _ _ _ _ _ 65. 00 INa 20 - . - . - - - 2. 23 

AlzOa _ _ _ __ _ 14. 28 K,O _ . _ _ _ 5. 19 

The rock is over 4 percent higher in silica than the 

average trachyte listed by Daly 7 and lower in alumina 

and soda. It is even more discordant with the average 

rhyolite, however, and the fact that no quartz was 

recognized in the thin section, while sanidine, which 

as a rule crystallizes later than quartz, is present, 

makes the assignment to the trachyte group fairly 

certain. 

Rhyolites.-Two occurrences of rhyolite were found, 

one about a mile southwest of benchmark 5045 on 

Deep Creek and the other in the northern part of 

Rodenhouse Wash. The Deep Creek exposure is part 

of an old neck, and to the south there are lavas that 

are related to it. The rock is greenish gray and contains a few phenocrysts of biotite and a sodic andesine 

that is almost completely altered to thompsonite. 

Small laths of plagioclase are enclosed in a glassy 

matrix, which has an index of refraction slightly less 

than 1.50 where unaltered. In most places the glass 

has been devitrified and consists of quartz, oligoclase, 

and orthoclase. A partial analysis shows clearly that 

this rock is most closely related to rhyolite: 

Partial analysis ()f rhy()lite 

[J. G. Fairchild, analyst] 

Si02 __ ------ -.- _ 70.30 INaaO __ ._ ------ 2. 66 

AhOa_ .___ __ __ __ ._ 14.92 K 0 _____ ._. ___ _ 2 4.37 

The Swansea rhyolite of the Tintic district 8 has a 

similar chemical composition but is quite different in 

mineralogic habit, being an intrusive rock. 

The rhyolite in Rodenhouse Wash is very different 

in appearance and texture from the rock described 

above. It is a poorly banded fine-grained purple rock 

that originally consisted of sparse plagioclase phenocrysts in a spherulitie matrix. It has undergone a 

rather complete recrystallization, however, and the 

phenocrysts are now composed of a finely crystalline 

aggregate that is probably oligoclase, in a matrix 

consisting of irregular and poorly defined areas of 

quartz and oligoclase. The boundaries of these two 

minerals show no relation to the outlines of the old 

spherulites. Megascopic crystals of a red garnet and 

microscopic laths of tourmaline are also present. 

'Daly, R. A., Igneous rocks and their origin, p. 21, New York, 1914. 


BLoughlin. O. F., Geology and ore deposits of the Tintic mining district, Utah: 


U.S. Geol. Survey Prof. Paper 107, p. 52, 1919. 
52 GOLD HILL MINING DISTRICT, UTAH 

Alkali basalt.-Small outcrops of alkali basalt are 

exposed on both sides of Overland Canyon from about 

the mouth of Blood Canyon to the eastern border of 

the quadrangle. The rock is also found near the 

mouth of North Pass Canyon and in Rodenhouse 

Wash. The North Pass Canyon exposure appears to 

be a dike, but the others are flows. . The small size 

and wide distribution of the present outcrops indicate 

that the rock formerly had a much greater extent. 

The rock is dark gray in all exposures and is characterized by the presence of numerous small reddishhrown grains of iddingsite. All but the dike are 

vesicular, and the vesicles locally have a calcite filling. 

Phenocrysts of glassy pyroxene and of feldspar as 

much as an inch in length are found in the dike and in 

the more easterly outcrops. 

The sections show that the chief constituents are 

olivine, largely altered to iddingsite, augite, and plagioclase. Magnetite, apatite, and amygdular calcite are 

present in minor amounts. Most of the iddingsite 

is deep reddish brown, but a little is distinctly yellowish. Its optical properties are similar to those of an 

iddingsite from Gatos Creek, Colorado, described by 

Ross and Shannon.9 Augite is present in notable 

quantities. In a specimen taken from the outcrop 

south of the Midas mine one large group of augite 

crystals has a spherulitic habit. Both andesine and 

oligoclase are present in the rock. Andesine occurs 

as larger lath-shaped crystals, and the sodic oligoclase 

as small anhedrons. Olivine, iddingsite, augite, and 

andesine make up the bulk of the rock, with only a 

small amount of interstitial material. This, however, 

instead of being glassy, as in the typical intersertal 

texture, is holocrystalline and is composed of small 

crystals of iddingsite, augite, and oligoclase. In this 

material most of the apatite is concentrated as long, 

slender needles. 

The strikingly porphyritic varieties from the eastern border of the quadrangle contain in addition to 

these minerals phenocrysts an inch or less in length 

of augite, andesine, quartz, and a potash-soda feldspar. 

The quartz phenocrysts are not abundant, and all show 

rather extreme resorption. The potash-soda feldspar 

is biaxial negative and has an optic angle (2V) estimated by C. S. Ross to be about 20°. Its indices of 

refraction are those of sanidine, ex being 1.518 ± 0.003. 

The extinction angle on cleavage plates parallel to 

010 are 4°-5° and on plates parallel to 001 up to 9°, 

indicating that the mineral must be triclinic. It shows 

no twinning. These properties are similar to those 

found by Iddings for a feldspar occurring in lithophysae in Yellowstone National Park, which analysis 

proved to contain 5.08 percent of N azO and 8.36 percent of KzO.10 

• Ross, C. S., and Shannon, E. V., The origin, oocurrence, composition, and 

physical properties of the mineral Iddingsite: U.S. Nat. Mus. Proc., vol. 67, p. 

14, 1925. 

'GIddings, r. P., Obsidian Clifl', Yellowstone National Park: U.S. Oeol. Survey 

Seventh Ann. Rept., p. 268, 1888. 

The presence of phenocrysts of this highly alkaline 

feldspar and quartz in certain of the lavas and its 

absence in others is thought to be the result of the 

rapidity with which the porphyries apparently consolidated. The lava on the eastern border of the 

quadrangle is much finer grained than the nonporphyritic varieties, and, although it is filled with vesicles, 

these are much smaller than normal, suggesting a cooling so rapid that the expelled volatile matter had no 

opportunity to collect. The result of so rapid a cooling would be the preservation of such phenocrysts as 

would otherwise be resorbed were the solidification 

more gradual. 

These rocks closely resemble in mineralogic composition those grouped by Rosenbusch under the name 

alkali basalt, in his faInily of trachydolerites.u The 

texture is that of basaltic rocks, and the abundance 

of soda-rich plagioclase feldspar is indicative of their 

alkaline affinities. 

A partial analysis of the rock indicates that the 

silica percentage is somewhat higher and the soda percentage somewhat lower than in the typical analyses 

of alkali basalts quoted by Rosenbusch, but the potash 

content is much higher than in the normal basalt. 

The specimen analyzed was obtained 1,200 feet northeast of benchmark 5509 in Overland Canyon. The 

rock here does not contain any of the large phenocrysts 

of potash-soda feldspar, and no potash mineral was 

recognized in the thin section, although the rock is 

holocrystalline. It is possible that the potash found 

by the analysis is present as a potassium-aluminum 

silicate in isomorphous combination with the plagio.,. 

clase, but there is no evidence for this view other than 

the apparent absence of a potassium-bearing mineral 

in the mode. 

Partial analysis of alkali basalt 

rJ. G. Fairchild, analyst] 

SiOa___ ---.-------- 47.361 KaO_________________ 2.66 

NaaO_ ____ __ __ __ __ 2. 80 

Pyroclastic rocks.-Tuffs and breccias are exposed in 

the vicinity of Deep Creek, in Rodenhouse Wash, and 

in Blood Canyon. 

The tuffaceous rocks west of Deep Creek and in 

Rodenhouse Wash are dark-purplish or reddish wellbedded rocks that contain larger fragments of andesine 

or labradorite, hornblende, and locally augite set in a 

matrix of glass fragments, which are locally devitrified, 

particularly near bedding planes. Most of the specimens examined are considerably altered. Another 

variety of tuff, which is poorly cemented, was found on 

the southwest slope of Twin Peaks. Except for a few 

small crystals of quartz, it is composed entirely of 

glass fragments, whose index of refraction is 1.495. 

The breccias in the Deep Creek region are of small 

extent and, in part at least, fill old volcanic necks. 

t! Rosenbusch, Barry, Elemente der Geste!nsiehre, 4th ed., by A. Osa.nn, pp. 4M458, Stuttgart, 1923. 
TERTIARY 

The rock fragments contained are entirely of the surrounding andesites or latites. The breccias in Rodenhouse Wash and Blood Canyon differ from those in the 

Deep Creek region in containing numerous fragments 

both of sedimentary rocks and of the quartz monzonite. The Rodenhouse 'Vash exposures are mostly 

well bedded and probably represent surface accumulations, but those in Blood Canyon are thoroughly 

altered and are thought to mark centers of eruption. 

ALTERATION OF THE VOLCANIC ROCKS 

Three kinds of alteration of the volcanic rocks have 

been recognized. One of these is thought to have been 

the result of reactions occurring before the complete 

co:qsolidation of the lava. The other two, which affected the minerals in the groundmass as well as the 

phenocrysts, were considerably later. Of these an 

alteration characterized by a series of silica minerals 

with calcite was restricted to volcanic necks or their 

vicinity, but the other, in which zeolites were abundantly developed, had no apparent relation to the 

necks. 

Some of the hornblende and magnetite and all of 

the iddingsite found in these lavas are clearly reaction 

products of the earlier-crystallized minerals with the 

still molten lava. A variety of chlorite with the optical properties of delessite seems to furnish a connecting 

link between these minerals and those produced by 

the other kinds of alteration, as it replaces augite, 

hornblende, biotite, and plagioclase phenocrysts and 

cuts the groundmass of various rocks in veinlets and 

in more irregular areas. In some places it has apparently been developed with magnetite in the alteration 

of biotite or hornblende, and in others it is associated 

with calcite, which as a rule is found with the later 

Ininerals. The conditions under which delessite forms 

seemingly have a wide range. A colorless chlorite 

whose index of refraction is much less than that of 

delessite has essentiallY the same habit as delessite 

but is not nearly as abundant. A mineral thought to 

be leverrierite was found with delessite in Blood Canyon, where it is locally abundant. 

Evidence of the alteration characterized by silica 

minerals was found only in specimens from volcanic 

necks or in rocks adjacent to the necks. The silica 

minerals are locally associated with calcite and occur 

as veinlets ranging from those of microscopic size to 

some that are nearly a foot in width. In places the 

veinlets show enlargements with rather irregular outlines. Tridymite, opal, chalcedony, quartz, and calcite are found in the veinlets, and where the age relations can be determined the order of formation is that 

given, with tridymite earliest and calcite last. 

The zeolitic alteration was rather widespread and affected both flows and pyroclastic rocks with no apparent relation to the sites of extrusion, although there are 

important exceptions in that two necks east of Deep 

SYSTEM 53 

Creek show a nearly complete replacement of plagioclase by thompsonite. The zeolites have replaced the 

feldspar phenocrysts and form irregular areas in the 

groundmass. Veinlets of the minerals are of minor 

extent. The minerals recognized are stilbite, analcite, 

thompsonite, and calcite. Locally these minerals are 

enclosed in veinlets of the silica minerals. 

The differences in habit and occurrence of the minerals of the two groups prompt the suggestion that the 

silica series represents a concentration from a larger 

body of cooling rock than the zeolite series. The 

wide-spread occurrence of the zeoli tic minerals indicates that the solutions which caused their formation 

were obtained from adjacent portions of the lava. 

AGE OF THE VOLCANIC ROCKS 

The volcanic rocks cannot be directly dated. So 

far as their relations to other rocks go, they are clearly 

younger than the Eocene (?) White Sage formation and 

the quartz monzonite, on both of which they rest 

unconformably. They are also thought to be younger 

than the Pliocene (?) sediments, which contain no 

pebbles of volcanic rock, although overlain by gravel 

which contains such pebbles. On the other hand, 

they are older than the Lake Bonneville sediments, 

from which they are separated by a period of considerable erosion. The Pliocene age of the prevolcanic 

sediments, however, is based (see p. 49) on their relations to the volcanic rocks. As far as stratigraphic 

evidence goes, therefore, the volcanic rocks are later 

than Eocene (?) and earlier than the Lake Bonneville 

Pleistocene. Geomorphic evidence, however, permits 

a somewhat closer dating. The volcanic rocks rest 

upon a surface which is very similar to the present one 

and which is clearly later than the normal faulting of 

the Basin Range type. The position of lavas and breccias in Rodenhouse Wash and Blood Canyon shows 

indisputably that they were erupted in valleys cut in 

an old topographic surface, the dissection of which 

was initiated by Basin Range faulting. The large area 

east of Deep Creek, moreover, apparently lies along 

the course of one of the Basin Range faults. Finally, 

the dike of alkali basalt in North Pass Canyon is 

thought to cut the gravel developed as a result of the 

faulting. The age of the Basin Range faulting is discussed on page 64, where it is shown that a Pliocene 

date is probable. With allowance for the prevolcanic 

erosion that has been noted, the date of eruption probably was in the later part of the Pliocene. 

GRAVEL AND CLAY (pLIOCENE (?) TO RECENT) 

About one-third of the area of the quadrangle is 

underlain by partly or completely unconsolidated sediments derived from the older rocks by weathering and 

erosion. They include gravel and clay deposited in 

the Pleistocene Lake Bonneville 12 in addition to 

12 Gllbert, G. K •• Lake Bonlleville: U.S. Oeol. Survey MOll. I, 1800. 

- f' 
54 GOLD HILL MINING DISTRICT, UTAH 

terrestrial gravel and clay that are both older and 

younger than the lake beds. Locally these deposits 

may be readily distinguished from one another, but 

in many places the assignment of an exposure to a 

definite chronologic position is impossible, either 

because it is isolated or because there is no sharp line 

of division between beds which in one place were 

clearly deposited at one time and in a second place at 

another. For the purposes of this report the beds will 

be arbitrarily grouped into three divisions-(l) older 

gravel and clay, (2) younger gravel and clay, (3) Lake 

Bonneville beds. 

OLDER GRAVEL AND CLAY 

At several places in the quadrangle there are exposures of gravel and clay which are clearly out of 

adjustment with regard to the present topography. 

These are thought to be remnants of deposits that were 

formed before the most recent faulting in the area. 

One area in which such gravel is displayed extends 

from North Pass Canyon north and east to the Midas 

mine. One almost continuous exposure of gravel in 

this area extends from the low ridge west of hill 6267, 

near the mouth of North Pass Canyon, northward to 

the divide between North Pass and Blood Canyons. 

Between these two places outcrops of bedrock are 

found at several points in the bottoms of gulches. The 

gravel lies as much as 450 feet above the present drainage channels. Here there appears to be almost no 

cementation of the beds. Pebbles and boulders as 

much as several feet in diameter lie in a matrix of 

smaller rock fragments and sand. The pebbles and 

boulders consist of rocks derived from formations 

exposed some distance to the west and north of the 

gravel outcrops, the formations adjacent to the gravel 

being almost entirely unrepresented. In Blood Canyon 

there are also gravel deposits on the higher slopes 

which are thought to be contemporaneous with those 

to the south. Still another area is south and southwest of the Midas mine, where the gravel is well 

cemented by calcium carbonate and contains almost 

no boulders of quartz monzonite, although there are 

extensive exposures of that rock immediately to the 

north. In all these localities there is some evidence to 

indicate that the gravel had been deposited before the 

volcanic rocks were erupted. (See p. 49.) 

Clifton Flat is also underlain by material now being 

actively dissected. The beds consist chiefly of clay, 

with only a minor amount of coarser material. Near 

the road leading to Clifton they overlie volcanic rocks 

and may therefore be in part younger than the gravel 

near N or~h ,Pass Canyon. 

Another area in which old gravel is exposed is on the 

west side of Dutch Mountain in a belt that roughly 

parallels Trail Gulch. This gravel is apparently unconsolidated and in places, as in the isolated patch 

east of hill 6518, contains a great deal of clay. The 

rocks represented by the boulders are those exposed to 

the east. The gravel was clearly deposited under 

conditions differing from those of the present time. 

The isolated patch mentioned above, for example, is 

found at the head of a canyon that drops 400 feet in 

a horizontal distance of 3,000 feet. In Woodman 

Canyon ridges made up of gravel rise over 200 feet 

above the canyon bottom, which, in many places, is 

cut in solid rock. 

These are the only areas in which the early age of 

the gravel or clay is definitely indicated. There are 

probably others, particularly north and northwest of 

Ochre Mountain and on the southeast side of Dutch 

Mountain, but in these the evidence is not clear. 

YOUNGER GRAVEL AND CLAY 

Several different kinds of sediment are included in 

the group of younger gravel and clay. The most 

extensive are the gravel deposits that flank all the 

highlands. These are poorly sorted, poorly stratified, 

and uncemented and do not differ materially from the 

gravel found throughout the Great Basin region. At 

least three stages of fairly recent deposition of the 

gravel was recognized. Less extensive are the sand 

and clay deposits in Deep Creek Valley, which lie 

above the level of Lake Bonneville. These occur not 

only along the present course of Deep Creek but also 

in a linear zone in the eastern parts of secs. 3, 10, 15, 

and 22, T. 9 S., R. 19 W. The younger gravel also 

includes the areas of talus mapped on the higher part 

of Dutch Mountain. These are limited to places in 

which the basal part of the Woodman formation is 

exposed. The sandstones which are so numerous at 

that horizon break up on weathering into small fragments and form talus slopes that conceal not only the 

beds of the Woodman but of the formation beneath. 

LAKE BONNEVILLE BEDS 

At the time of maximum extent of ,Lake Bonneville 

nearly one-fifth of the quadrangle was under water. 

For the most part the flooding by the lake waters 

resulted only in a reworking of previously deposited 

gravel. In two areas, however, lacustrine clay was 

deposited. These were in the Deep Creek Valley and 

in the northeast corner of the quadrangle. 

In many places the reworking of the older gravel 

was slight and is expressed chiefly in distinct beach 

lines. Locally, however, especially where outcrops of 

hard rock influenced the shore currents, impressive 

shore features were developed. One of the most striking of these is the large hooked spit on the east side of 

Dutch Mountain. This is over a mile long and for 

much of this distance rises 600 feet above the gravel 

slope to the east. There is a smaller similar spit to 

the south on the north side of Tribune Gulch, and 

another on the south side of the prominent quartzite 

hill east of the Rube mine. All three of these were 

built up to the highest level of the lake, an altitude of 

about 5,200 feet. 
GEOLOGIC STRUCTURE 55 

Another prominent feature resulting from the reworking of older gravel by the Lake Bonneville waters 

is the bar half a mile south of the dry lake in Bar Creek. 

This narrow, even-topped ridge approaches the regularity of a railroad grade. 

The clay deposits in the localities mentioned above 

are light-colored and calcareous and are similar to those 

found throughout the area formerly covered by the 

lake.l

• 

GEOLOGIC STRUCTURE 

The accompanying geologic maps (pIs. 1 and 2) show 

a notable lack of continuity in the older sedimentary 

formations that is in large part the result of a protracted period of crustal unrest, during which these 

older rocks were warped and complexly faulted. By 

means of the mutual relations of the faults and, to a 

less extent, the folds, a structural history of the quadrangle was deciphered that appears to be unique for 

this portion of the Great Basin. 

The determined sequence of events indicates that 

the deformation was cyclic in character, in that an 

initial stage in which compressive forces were active 

was followed by one in which normal faulting took 

place. (See p. 65.) Five cycles of this character 

were distinguished; the first two are thought to have 

been of Cretaceous or early Eocene age, the third was 

contemporaneous with the Eocene (?) \Vhite Sage formation, and the fourth and fifth are considered to have 

been of about the same age as the quartz monzonite 

intrusion. 

There is a progressive variation in the character of 

the structural features developed during the successive 

cycles. Folding appears to have been dominant in the 

compressive stage of early cycles, low-angle thrust 

faults of large throw characterize this stage of the third 

cycle, and transverse or tear faults are particularly 

abundant in the later cycles. It is suggested that the 

change in character through the five cycles is the 

reflection of a progressively lighter load and that 

transverse faults have optimum conditions for their 

formation at or near the surface. 

The normal faults that were formed in the second 

stage of each of the five cycles show a decrease in both 

number and intensity in the successive cycles. A 

possible explanation for this decrease is considered to 

be that the additional strength or rigidity imparted 

by the successive periods of compression made relaxational movements, as typified by the normal faults, 

less and less necessary. 

A later period of normal faulting followed the 

development of a post-mature erosion surface over the 

older structural features. This later faulting is 

thought to have begun in late Pliocene time. The 

faults are not all strictly eontemporaneous, and many 

of them utilized earlier fault planes. 

13 Gilbert. o. R., Lake Bonneville: U.S. Oeo1. Survey Mon. I, p. 100, 1800. 

Nolan, T. B., Potash brines in the Oreat Salt I,ake Desert, Utah: U.S. Oeol. 

Survey Bull. 795, pp. 32-34, 1927. 

STRUCTURAL CYCLES 

In a region that is structurally as complex as the 

Gold Hill quadrangle, a detailed geographic description of folds and faults tends to conceal the succession 

of events and to becloud the correlation of related 

features that are widely separated areally. The 

following section gives a chronologic account of the 

major structural features and outlines their relations 

to one another. The detailed observations upon which 

this section is based are given on pages 66-91, where 

the structural features in each of the six structural 

blocks into which the quadrangle is divided are described geographically. The fault map of the quadrangle (pI. 3) and the geologic structure sections on 

plates 1 ll,nd 2 will be found useful in the reading of 

~oth discussions. 

FIRST CYCLE 

First stage.-Structural features assignable to the 

first stage of the first cycle were not widely recognized. 

This may be due in part to the impossibility of making 

age assignments for isolated features and in part to 

the probability of renewed movement along faults 

that first became active at this time. Two rather 

minor low-angle faults, thought to be thrusts, and local 

folds are found on the southwest flank of Ochre 

Mountain, and as they are cut by normal faults that 

definitely belong to the second stage of this cycle, they 

are considered to record an initial stage of compression. 

The meager evidence available provides scant information as to the. character of the compressive forces. 

Transverse faults appear to be absent, but the folds 

and reverse faults are so few and small that their relative importance is not known. 

Second stage.---Several normal faults with relatively 

small throw on Ochre Mount,ain are clearly older than 

the minor thrusts that belong to the second cycle. 

There is also a group of small normal faults on Dutch 

Mountain of similar strike that are cut by faults of 

the second cycle. Both of these groups are therefore 

believed to represent a period of rather wide-spread 

normal faulting that followed the minor thrusting and 

folding of the first stage. 

SECOND CYCJ.E 

First stage.-·Folds, thrusts, and transverse faults 

were formed during the first stage of the second cycle, 

but folding was far more intense than faulting. The 

continuity of the folds has been largely destroyed by 

the disturbances of later cycles, but the portions that 

can be examined leave no doubt that they were of considerable magnitude. 

The Deep Creek Mountains south of North Pass 

Canyon appear to represent the western half of a major 

anticline whose axis coincides approximately with the 

eastern border of the mountains, as easterly dips are 

found in the Prospect Mountain quartzite south of 

Dry Canyon. In North Pass Canyon itself the Cambrian formations that crop out near the mouth of the 
56 GOLD HILL MINING DISTRICT, UTAH 

canyon show an anticlinal structure that is thought 

to be a continuation of that found farther south. 

North of thi<o anticline an equally large but unrelated 

anticline in Mississippian and Pennsylvanian rocks is 

exposed around the borders of the south half of Clifton 

Flat. A much-faulted core of Ochre Mountain limestone is overlain on each side by a large thickness of 

the Oquirrh formation. The beds of the Oquirrh on 

the west flank show some minor superposed folds that 

were probably formed during a later cycle. 

A third large fold, a recumbent anticline, is best 

exposed on the southern flank of Twin Peaks in the 

northwestern part of the quadrangle, and its axis may 

be traced for some distance. The axial plane of the 

fold strikes about N. 15° E. over this area, but in 

detail it varies considerably because of later warping. 

All three of these major folds are cut by normal 

faults that are older than the thrust faults formed. 

during the succeeding cycle, and it is believed that they 

are therefore essentially contemporaneous. Their 

present close association is fortuitous, as each now lies 

in a separate thrust plate. 

The thrusts that are contemporaneous with these 

folds are for the most part of minor importance. The 

only recognized large thrust of this age is found on 

Dutch Mountain. This has been called the Dutch 

Mountain thrust, as it has a nearly continuous outcrop around the crest of the mountain. Stratigraphically the thrust is not striking, because it has Ochre 

Mountain limestone above and the Woodman formation below-the normal sequence. . The bedding of 

both formations is discordant to the contact, however, 

and the thickness of the underlying Woodman formation varies notably from place to place. 

Continuations of the thrust are found to the south 

on peak 7011, on the south side of Pool Canyon, and, 

at a much lower altitude, on the west side of Accident 

Canyon. At both localities the relations are the same, 

the Ochre Mountain limestone resting upon the W oodman formations, but in these exposures the Woodman 

is considerably crumpled. 

The segment near the mouth of Accident Canyon 

has a rather low dip, comparable to that shown by the 

thrust below the summit of Dutch Mountain. As the 

fault is traced south along Accident Canyon, however, 

the dip steepens and is as high as 60° at the point where 

it is cut off by a later normal fault. This zone of 

steeper dip between two portions with relatively flat 

dip must be an original feature of the thrust, as its 

origin by a later warping is precluded by the lack of 

similar warping in the adjacent beds. The absence of 

such warping is shown rather conclusively by the inliers 

of Madison limestone near the south end of the steeply 

dipping portion of the fault. 

Some transverse faulting also occurred during this 

stage. The west-northwest fault in North Pass Canyon and the parallel Pool Canyon fault on Dutch 

Mountain appear to have been formed at this time. 

Other faults with similar strike became active in the 

third cycle, however, and locally it is difficult to distinguish between the two ages. 

The dominant structural features of this stage of 

the second cycle are folds of considerable magnitude. 

Thrust faults are rather numerous but have relatively 

small displacements; and transverse faulting appears 

to have been of even less magnitude. The thrust 

faults appear to have been formed by the sliding of 

more resistant stratigraphic units over less resistant 

underlying beds, which yielded to the compression 

by crumpling. Their character, as well as the size 

of the folds, suggests that the deformation took place 

under a relatively heavy load. The strike of the transverse faults and the strike of the axis of the recumbent 

fold indicates that the compressive forces were directed 

from the west-northwest. 

Second stage.-Normal faults that were formed during the second stage of the second cycle are found 

throughout the quadrangle. They do not appear to 

be quite as numerous as the faults of this character 

developed in the preceding cycle, but many of them 

have unusually large throws. Several of them are 

also characterized by the fact that they mark lines of 

weakness that persisted throughout several cycles. 

The fault along the east base of the Deep Creek 

Mountains, for example, has a throw of 6,000 feet, of 

which 4,000 feet may be assigned to this cycle, as a 

thrust formed in the next cycle is displaced only 2,000 

feet. Similarly the Spotted Fawn fault, on the east 

side of Dutch Mountain, has a throw of 2,000 feet, of 

which 1,500 feet, as shown by its relations to a thrust 

of the next cycle, can be assigned to this stage. The 

Trail Gulch fault, on the west side of Dutch Mountain, 

has had a comparable history. The Tank Wash and 

Bar Creek faults, in the northwestern part of the 

quadrangle, are also of this class, with total throws of 

about 4,000 and 5,000 feet respectively, of which the 

greater part took place during this stage. 

THIRD CYCLE 

First stage.-In the first stage of the third cycle 

large-scale overthrusting was accompanied by relatively minor transverse faulting and slight folding. 

Two large overthrusts were formed during this stagean earlier one, which appears to have been limited 

between two transverse faults, and a later one, which 

has overridden the earlier structure.. A long period of 

erosion is thought to have separated the beginning of 

. this cycle from the last stage of the preceding one. 

Although the total movement along either of the 

thrusts cannot be determined from the evidence provided within the quadrangle, it must have been rather 

large, because distinctive facies of the Carboniferous 

formations are found above each of the thrusts (p. 23 

and fig. 5). 
r 


GEOLOGIC 

The earlier or North Pass thrust is exposed in only 

a few places, but the distribution of the central facies 

of the Carboniferous rocks makes it fairly certain that 

the thrust extends as far north as the Pool Canyon 

transverse fault, on the south side of Dutch Mountain. 

In North Pass Canyon the thrust is exposed in only 

one small outcrop. Minor structural features accompanying the thrust are locally well exposed, however, 

and by piecing these together a fairly adequate picture 

of the structural conditions may be obtained. The 

most striking of these minor features are found on the 

west flanlt of the anticline and north of the transverse 

fault along the floor of the valley, both of which were 

formed in the preceding cycle. They consist of thrust 

plates of the more resistant pre-Carboniferous formations that have overridden the axis of the anticline. 

The plates decrease in number and in thickness eastward, and at the mouth of the canyon, north of hill 

6267, only one 100-foot plate, which is composed of 

Laketown dolomite, remains. This plate is overlain 

by beds of the Oquirrh formation that are essentially 

continuous with the large outcrop that" nearly surrounds Clifton Flat. The contact between the shattered Laketown dolomite and the Oquirrh formation 

is the plane of the North Pass thrust. 

The minor thrusts very clearly are limited southward by the older transverse fault, and it seems rather 

certain that the main North Pass thrust was also so 

limited, as it is nowhere exposed to the south, although 

many places along the ridge lines reach sufficiently 

high altitudes to have been cut by the thrust if it had 

originally extended that far. 

The relations of the thrust plates beneath the main 

thrust to the older anticline are those that would 

result had the anticline been deeply eroded and then 

subjected to compression from the west, the more 

competent beds on the western limb of the fold riding 

forward over the eroded core and extending for short 

distances farther east. This in turn implies that the 

main thrust at this locality was also moving over a 

surface of erosion. A measure of the amount of erosion 

is given by the normal fault along the eastern front of 

the Deep Creek Mountains, which had a pre-thrust 

throw of 4,000 feet. By the time of the thrusting, 

however, erosion must have completely beveled across 

the fault, for the thin plate of Laketown dolomite 

crossed it without interruption. 

The North Pass thrust may also be located rather 

closely at two other localities-along the Lincoln 

Highway south of Ochre Mountain and in the southeast corner of the quadrangle. These provide a measure of the minimum movement along the thrust, for 

they are about 9 miles apart in a direction approximately at right angles to the strike of the thrust. 

The North Pass thrust appears to be limited northward by the Pool Canyon transverse fault, as the 

Carboniferous formations of the central facies that 

35311-35---6 

STRUCTURE 57 

overlie the thrust are cut oft' by the transverse fault; 

north of the fault lower Paleozoic formations are exposed that are thought to be the continuation of those 

exposed south of the parallel transverse fault in North 

Pass Canyon. The North Pass thrust cannot be 

recognized north of the Pool Canyon fault, and evidence is provided by a nearly contemporaneous thrust 

that it was never present in that region. 

The limitation of the North Pass thrust between 

two transverse faults that are, in part at least, older 

. than the thrust is thought to be the result of the erosion 

that took place between the second and third cycles, 

which appears to have exposed the resistant Prospect 

Mountain quartzite both to the north and south of the 

transverse faults and thus prevented the overriding 

that is found between the faults, where the quartzite 

was deeply buried. 

The second major thrust, the Ochre Mountain 

thrust, has a wider extent and is well exposed on both 

Ochre Mountain and Dutch Mountain. On the 

south side of Ochre Mountain this thrust abuts against 

a younger transverse fault, beyond which it has been 

almost entirely removed by erosion, and on the north 

it disappears beneath the gravel flanking Dutch 

Mountain. 

The Ochre Mountain thrust, like the North Pass 

thrust, is thought to be an "erosion thrust" in the 

sense that the overriding block moved oyer the then 

existent surface. The chief evidence for this belief is 

found in the behavior of the overriding block where 

the thrust crosses the Pool Canyon transverse fault. 

Although there has been an intrusion of quartz monzonite along the transverse fault, the major relations 

between the two faults are readily seen. The thrust 

is clearly the younger, as there is no sign of the transverse fault in the beds above the thrust. North of 

the transverse fault a gently dipping sequence of beds 

with Madison limestone at the base lies above the 

thrust. South of the transverse fault, however, the 

beds are considerably disturbed and are even locally 

overturned, and beds high in the Woodman formation 

lie immediately above the thrust. South of the transverse fault, also, the thrust is about 300 feet higher 

than it is to the north. The relations outlined indicate 

that the overriding thrust plate was considerably 

hindered in its forward movement at this place, and it 

seems probable that the structural features in the 

oyerridden beds would prove to be an obstacle only if 

they were exposed at the surface at the time of thrus.ting. The occurrence of thin thrust plates of a single 

formation below the main thrust on both Dutch 

Mountain and the north slope of Ochre Mountain also 

imply, as in the North Pass thrust, that the Ochre 

Mountain thrust reached the surface. 

In addition to the nearly continuous outcrops of the 

Ochre Mountain thrust on Ochre Mountain and Dutch 

Mountain, the thrust is exposed in several places in. 

..~ 
58 GOLD HILL MINING DISTRICT, UTAH 

roof pendants within the quartz monzonite stock and 

,also in "windows" on the northwest slope of Dutch 

Mountain and within Ochre Mountain. The minimum movement along the thrust as indicated by these 

exposures may be placed at 4 miles, but obviously the 

total amount is much more, as the lithologic differences 

between the two facies of the Carboniferous formations 

persist throughout this distance. 

The Ochre Mountain thrust and the North Pass 

thrust have been placed in the same structural cycle, 

because each of them has the same relations to the 

faults and folds of other cycles. In Pool Canyon the 

Ochre Mountain thrust is clearly shown to be the 

younger of the two, although there is some evidence 

at that place to indicate that the age difference is not 

great. The thin-bedded limestones and sandstones of 

the Oquirrh formation beneath the thrust south of the 

Pool Canyon transverse fault are much less resistant 

to erosion than the massive lower Paleozoic dolomites 

north of it. The weaker beds now stand at a higher 

altitude, however, and as the Ochre Mountain thrust 

appears to have moved over the surface at this point, 

it follows that they must also have been at a higher 

altitude at the time that thrust was active. This in 

turn implies that but little time could have elapsed 

between the Ochre Mountain thrust and the North 

Pass thrust, which brought the weaker beds into the 

position they now have. 

The slight difference in age between the two thrusts 

provides additional evidence that the North Pass 

thrust was limited northward by the Pool Canyon 

transverse fault, for north of that fault the Ochre 

Mountain thrust plate rests upon lower Paleozoic formations without the intervening mass of Carboniferous 

rocks that forms the North Pass thrust plate. As the 

two thrusts were almost contemporaneous there was 

obviously no time for the North Pass thrust plate to 

be eroded north of the Pool Canyon fault before the 

Ochre Mountain thrust was formed, and it must 

therefore never have extended that far. 

The two major thrust faults were accompanied by 

many small thrusts, and in addition there appears to 

have been a reversal of movement along at least one of 

the older normal faults during this stage. On the western or hanging-wall side of the Trail Gulch fault, for 

example, the Oquirrh formation shows several small 

folds that in places are overturned i similar folds are 

absent in the footwall. Furthermore, neither this 

!ault nor the beds on its hanging wall have been 

affected by the deformation shown by the Ochre 

Mountain thrust and the Mississippian beds above 

the thrust in the region where the thrust crosses the 

Pool Canyon transverse fault. Both of these fe-attires 

are most readily explained by the assumption of renewed movement along the Trail Gulch fault, by 

which beds on one side of the fault could be deformed 

independently of those on the other side. 

Folding during this stage was confined to the 

relatively small drag folds that are associated with the 

thrusts and with the renewed movement along the 

Trail Gulch fault. Some gentle broad warping may 

have taken place, such as the warping of ,the axial 

plane of the recumbent anticline of the second cycle, 

but it appears to have been of minor intensity. 

Several west-northwest transverse faults also appear to be of this age, as they have the same 

relations as the major thrusts to other faults. Some 

transverse faults of this strike became active during 

the second cycle, however, and others,' such as the 

Pool Canyon fault, must have been active during 

both cycles. 

This stage of the third cycle appears to have been 

initiated, after a protracted period of erosion that 

followed the second cycle, by a long period of thrusting. 

The two most extensive overthrust masses in this 

region both moved over the then existing surface. 

Transverse faults were formed in moderate abundance, 

but only minDr folds. All these features are thought 

to indicate €hat the deformation took place under a 

relatively light load. As the transverse faults correspond in strike to those of the preceding cycle, it is 

thought that the compression came from the westnorthwest. 

Second stage.-The normal faults of the second stage 

are neither abundant nor of large throw. On Dutch 

Mountain and Ochre Mountain much of the normal 

faulting of this stage took place along older faults. 

In both areas most of the faults of this age cut the 

Ochre Mountain thrust, and the difference in throw 

of the thrust and of the rocks below the thrust provides 

a measure of the later movement, which in all the 

examples known has been relatively small. 

FOURTH CYCLl<J 

First stage.-The principal structural features of the 

first stage of the fourth cycle are four nearly east-west 

transverse faults, along which the horizontal movement may have been a mile or more. Minor steep 

thrusting and a small amount of gentle warping accompanied the transverse faulting, and two series of faults 

that are thought to have conjugate relations are 

associated with the most northerly transverse fault 

(pp. 83-84). 

These transverse faults cut both the major overthrusts of the preceding cycle and the normal faults 

that followed the overthrusting. For this reason as 

well as the change in the strike of the transverse 

faulting, they are considered to represent a new structural cycle. 

The most southerly of the transverse faults is the 

Dry Canyon fault. It appears to have a nearly vertical dip throughout its exposed extent of 4 miles. The 

beds on the north side of the fault have been shifted 

about 1,000 feet to the east. 

-

GEOLOGIC STRUCTURE 59 

The other three faults have somewhat more complex 

relations. The Blood Canyon transverse fault may 

be traced for nearly 8 miles and over much of this 

distance has a steep dip similar to that of the Dry 

Canyon fault. To the east, however, its dip is notably 

flatter, and the thin':'bedded members of the Oquirrh 

formation adjacent to it show complex crumplings 

that are absent away from the fault. A measurement 

of the movement along this fault is difficult, because 

for a considerable distance it separates the overriding 

block of the North. Pass thrust from the overridden 

block. However, on the basis of the correlation of 

two older west-northwest transverse faults that. are 

found on the two sides of the Blood Canyon fault, the 

south side is thought to have moved about a mile 

to the east. 

The transverse fault on the south slope of Ochre 

Mountain also flattens notably eastward. The change 

in dip here appears to coincide "ith the presence of the 

Ochre Mountain thrust in the block south of the fault. 

The throw along the transverse fault cannot be exactly 

determined but must be large, because the Oquirrh 

formation overlies the Ochre Mountain thrust south 

of the fault, whereas \0 the north the Ochre Mountain 

limestone is above the thrust. If the block south of 

the transverse fault has moved to the east, as would 

seem probable from the fact that the thrust is at a 

higher altitude on this side, a minimum movement 

of 3 miles appears necessary. . The thrust has been 

considerably warped adjacent to the transverse fault, 

however, and the north side may therefore have moved 

to the east; in that case the movement may be nearer 

to 1 mile. 

The remaining major transverse fault of this stage, 

the Garrison Monster fault, is the most complex of 

the group. Its exposures are for the most part at or 

near the altitudes at which the Ochre Mountain thrust 

crops out, and the structural complexities observed 

appear to be the result of this coincidence, for to the 

east, at altitudes well below the thrust, the transverse 

fault is a simple steep fracture. To the west, near 

the thrust, the simple fault is replaced by a zone of 

moderately northward-dipping faults, which effect the 

same displacement as the single fault to the east. 

The strike of some of the faults in this zone changes 

to northeast and east-northeast as they extend westward and southward. Such continuations may show 

either normal or reverse faulting, but because of their 

relations to the faults in the transverse fault zone 

itself it seems certain that the dominant movement 

along them has been horizontal. 

The amount of horizontal movement along the transverse fault in the vicinity of the Garrison Monster 

mine must have been about 1% miles, the rocks north 

of the fault moving to the east. Westward in the 

fault zone, however, both the number of faults in the 

zone and the amount of displacement decrease, and 

in the low hills that end the northwesterly spur of 

Dutch Mountain the fault zone can no longer be 

recognized. 

The behavior of the Ochre Mountain thrust on both 

sides of the transverse fault appears to throw some 

light on the mechanics of faults of this type. North 

of the transverse fault exposures are few but are sufficient to show that the thrust surface cannot be greatly 

deformed but must rise with a relatively gentle slope 

to the east. South of the transverse fault, however, 

the numerous outcrops indicate that the thrust plane 

has been folded into a shallow syncline whose axis 

roughly parallels Accident Canyon and a marked anticline that coincides more or less closely with the crest 

of Dutch Mountain. The anticlinal axis appears to 

die out southwestward. 

The block north of the transverse fault, which has 

apparently undergone no folding, has moved eastward 

relative to the folded block to the south, suggesting 

that the true movement may have been westward by 

the southern block. There are several objections to 

this supposition, however-one being that in the previous cycles the true direction of movement, wherever 

determinable, has been eastward. A more weighty 

objection lies in the fact that the Garrison Monster 

fault must curve to the north beyond its present most 

easterly outcrop, as it is clearly absent in the exposures 

of Prospect Mountain quartzite east and south of its 

projected continuation. The change in strike to the 

northeast is difficult to reconcile with a westward 

movement of the southern block. 

An eastward movement of the block north of the 

transverse fault, combined with the lack of contemporaneous folding in the block, suggests that the 

crustal shortening required by the movement was 

accomplished by thrusting, and the change in strike of 

the transverse fault eastward may be interpreted as 

marking the line of overriding. The folding and minor 

reverse faulting in the block south of the transverse 

fault is of sufficient magnitude to account for the 

shortening required on that side, and the fact that the 

folding dies out southward appears to confirm the 

conclusion that the northern block was the active one. 

The general relations of the Garrison Monster trans.; 

verse fault are shown diagrammatically in figure 8. It 

is not known how widely applicable these relations are 

to the other transverse faults in the quadrangle, but 

the lack of outcrops east of the similar transverse 

fault on the south side of Ochre Mountain suggest 

strongly that it also passes into a thrust. The flattening of the Blood Canyon fault eastward may also 

indica te that the same relations hold for it. 

The compressive forces of this stage seem to have 

been relieved by movements that were accomplished 

under a very light load, for the dominance of faulting 

over folding is extreme, faults on the north side of 

Dutch Mountain even appearing to replace some of 
60 GOLD HILL MINING DISTRICT, UTAH 

the drag effects that would normally be expected to 

accompany transverse faults of this magnitude. 

Second stage.-There appears to have been essentially no normal faulting in the fourth cycle. In the 

Ochre Mountain and Dutch Mountain blocks there 

are a few faults that may belong to the second stage 

of this cycle, but it is difficult to distinguish them from 

the conjugate faults of the first stage. 

FlF"I'lI CYCLE AND FAULTS RELATED TO THE QUARTZ 

MONZONITE INTRUSION 

The structural features developed in the first four 

cycles are all earlier than the quartz monzonite intrusion, for at different places features of each cycle are 

terminated by the intrusive contact. In some places, 

however, the intrusive rocks are affected by small 

thrust faults, notably east of hill 5675, on the north 

FIGURE 8.~Block diagram showing the generallzed structure along the Garrison Monater 

transverse fault. ' 

side of Rodenhouse Wash, and in a tunnel on the northeast side of Ochre Mountain, and these are thought to 

indicate a relatively minor recurrence of the compressive forces that were so active in the preceding cycles. 

In addition to these faults, there are several other 

faults in or adjacent to the quartz monzonite stock 

that are thought to have a causal relation to it. One 

group of these faults is localized along and is parallel 

to the western border of the intrusion and has caused 

very large displacements in the Ochre Mountain thrust 

plane. Partly because faults of this magnitude do, not 

cut the thrust at other localities and partly because 

the zone coincides with a belt of ore deposits that are 

characterized by high-temperature minerals, the fault 

zone is thought to mark the location of the primary 

channel through which the stock was intruded. 

A much larger group of faults is distributed 

throughout the intrusive area. ,These faults have 

everywhere a small throw, but have very diverse orientation as well as time relations. They are thought to 

have resulted from the stresses set up at intervals 

during the slow cooling of the stock. 

PROGRESSIVE VARIATION IN THE ClI.ARACTER 


OF DEFORMATION 


In the summary account of the five cycles in the 

preceding pages, mention was made of an apparent 

dominance in each cycle of certain types of structure. 

Thus the first cycle was characterized by an abundance of normal faults; the second by folds, with only 

a minor anlOunt of thrusting and transverse faulting, 

followed by'a few normal faults of large throw; the 

third, by predominant thrusting succeeded by minor 

normal faulting; and the fourth, by transverse faults 

accompanied by faults along which the chief movement 

appears to have been horizontal. The fourth cycle 

also appears to have had but little normal faulting. 

Because of the dominance of folding and 

the character of the thrusting in the second 

cycle, it was deduced that the deformation 

proceeded under a moderately heavy load. 

The absence of folding and the abundance 

and character of the thrusts and transverse 

faults in the third and fourth cycles prompt·· 

ed the suggestion that the load was con­

.siderably lighter during these times. 

The fact that the load appears to have 

been less in the more recent cycles of deformation is not in itself surprising, for it 

would appear to be the natural result of a 

progressively greater sum total of erosion 

during a long-continued period of diastrophism. The interesting feature, however, is the implication that transverse 

faults, which overshadow in importance 

other structural forms in the fourth cycle, 

have optimum conditions for their formation at a time when the overlying cover is 

at a minimum. 

This relation cannot of course be regarded as proved 

from the evidence in the Gold Hill quadrangle. It 

might be considered, for example, that as transverse 

faults were formed in both the second' and the third 

cycles their apparent dominance in the fourth cycle is 

not real and is a result of incomplete exposures. 

Furthermore, the change in strike of the transverse 

faults of the fourth cycle, which indicates a change,in 

the direction of the causative force, might be taken to 

mean that the conditions accompanying the compression also changed in a way to favor transverse faulting 

rather than folding or thrusting. Although neither of 

these objections can be successfully refuted from the evidence at hand, the relations displayed by some of these 

faults, particularly the Garrison Monster transverse 

fault, suggest strongly that there is a causal relation 

between transverse faulting and,~ relatively light load. 

The apparent decrease in the amount and intensity 

of normal faulting in the successive cycles cannot be 

readily explained by a progressive decrease in load. A 
GEOLOGIC STRUCTURE 61 

widely accepted theory to explain the sequence of folding or thrustirig followed by normal faulting assumes 

that the normal faults are in the nature of relaxational 

movements to restore equilihrium after excess compressional movements that originated through It lack 

of immediate resistance in the earth's crust. Although 

there are some objections to this theory, it appears to 

provide an explanation for the progressive variation in 

the normal faulting. It would appear that during the 

initial period of compression, in the first cycle, the 

crust in this area was notably deficient in its resistance 

to compressive movements in excess of those necessary 

to relieve the stress; on the relief of the compression, 

therefore, a large amount of normal faulting occurred. 

When the compressive forces of the second cycle became effective, however, the local crust may have 

become sufficiently strengthened or rigid during the 

preceding compression, perhaps by reduction of pore 

space or by recrystallization or some similar process, 

to resist the compressive forces much more effectively, 

and therefore it underwent much less subsequent normal faulting. Each successive period of compression 

would thus strengthen the crust, so that in the fourth 

cycle relatively little excess movement occurred during 

compression, and, as a result, practically no normal 

faulting was necessary at the end of the cycle. 

LATE NORMAL FAULTING AND ITS RELATION TO THE 


PRESENT TOPOGRAPHY 


In~ addition to the folds and faults developed during 

a measure of the movement along the late normal 

faults that separate these remnants. 

The fault most directly connected with the old 

erosion surface is that along the west sides of Ochre 

Mountain and the Deep Creek Mountains. Although 

there is no direct stratigraphic evidence for it, the convergence of several kinds of reasoning leaves little 

doubt as to its presence. First of all, the remarkably 

linear boundary between the mountains and the gravelfilled valley is extremely suggestive of faulting, as it 

transgresses the geologic structure to a notable degree. 

The rock-floored pass on the south side of Ochre 

Mountain through which the Lincoln Highway enters 

the Deep Creek Valley, together with the youthful 

character of the drainage all along the mountain front, 

also implies recent uplif~. Additional evidence is provided by the fact that the eastern slope of Ochre 

Mountain is a tilted continuation of the old erosion 

surface southeast of the town of Gold Hill. The close 

relationship between the two surfaces is shown by the 

absence of any distinct topographic break between 

them, by the presence on the eastern slope of the 

mountain of a partly entrenched drainage system that 

is approximately equivalent in maturity to that in the 

region near the town, and by the presence of a moderately deep soil on the ridges of this portion of the 

mountain. This tilted surface on the eastern slope of 

Ochre Mountain (pI. 6, A) contrasts strongly with the 

abrupt western front, with its excellent exposures and 

youthful drainage pattern (pI. 6, B). 

.the five structural cycles and during the intrusion of the . The fault must terminate rather abruptly northward 

quartz monzonite, there are several normal faults that about at its intersection with the trail from Gold Hill 

are considered to be of relatively recent age, because to the Erickson ranch, because to the north the old 

of their topographic relations. In the present section surface continues across the line of the fault unaffected. 

these faults, which are shown on plate 3, will be con­ Southward the faUlt continues for several miles beyond 

• sidered as a group and their supposed influence on the the southern border of the quadrangle. The throw 

development of the present topography described. along the fault cannot be definitely determined. From 

A feature whose recognition leads to a considerably the evidence of tilting on Ochre Mountain it is apparent 

increased knowledge of these late faults is a dissected that the block east of the fault must have moved 

erosion surface that has been partly preserved in upward about 1,500 feet. The block west of the fault 

certain areas in the quadrangle. The surface, judged is covered by gravel, but it must have been depressed 

from these remnants, must have been well past mat'l}.­ at least 1,000 feet, as shown by the altitude of the 

rity and have approached the condition of a peneplain. graveL It is rather strongly indicated, therefore, that 

It is best exposed southeast and southwest of the town the movement along the fault has been accomplished 

of Gold Hill (pI. 6, 0, D), where it is r~presented by It by a combination 9f elevation in the footwall block and 

group of closely spaced hills and ridges, all of which depression in the hanging-wall block. 

have an altitude close to 6,000 feet. The drainage The fault just described is matched on the east side 

pattern of this area is also that of postmaturity, con­ of the mountain area by two major and probably sevtrasting strongly with the youthful drainage found on eral minor faults of relatively recent age. The more 

the west side of Ochre Mountain and in the Deep southerly of the two major faults is indicated by 

Creek Mountains. stratigraphic as well as physiographic evidence~ This 

It seems improbable that a surface such as this is the fault along the eastern front of the Deep Creek 

could have been originally limited to an area as small Mountains south of Overland Canyon. There hal'! 

as the present one. Therefore, when remnants of a been a 2,000-foot throw along this fault subsequent to 

postmature surface in other parts of the quadrangle the North Pass thrust (seep. 68), which is thought to 

were recognized, they werecotrelated with this one, be of relatively recent date. This figure corresponds 

and the differences in altitude were considered to give with the difference in altitude between the low hills 
62 GOLD HILL MINING DISTRICT. UTAH 

east of the fault and the long east-west ridges on each 

side of North Pass Canyon, both of which are considered to be remnants of the old erosion surface. 

The surface represented by the low hills east of the 

fault may be continued through Blood Canyon to 

Clifton Flat and thence north to the type area south 

of Ctold Hill. The correlation of the east-west ridges 

is less evident. In the first place, the ridge lines on 

both sides of Dry, Sheep, and North Pass Canyons 

reach altitudes on their east ends that are about the 

same as those found throughout the ridge. This, combined with the youthful, essentially unforked drainage, 

seems to require an original relatively flat surface that 

has been recently uplifted and has undergone relatively 

little erosion except along the master streams. Trus 

view appears to be confirmed by several areas characterized by poor exposures, owing to deep weathering 

and slight relief along the ridge lines, as at the head of 

the south fork of Dry Canyon and at the head of Sheep 

Canyon. 

The ridge lines have progressively lower altitudes 

from south to north. The higher areas surrounding 

Uiyabi Canyon continue the trend still farther northward. The region about the canyon, however, is topographically the continuation of the east side of Ochre 

Mountain and therefore provides the connecting link 

between the nearly fiat but elevated portion of the 

surface to the south with the tilted portion on Ochre 

Mountain. This rather devious attempt to establish 

the topographic throw along the fault would not be 

particularly convincing were it not for the coincidence 

of the topographie displacement with the stratigrapruc 

throw at the mouth of the North Pass Canyon. 

The fault has been traced northward to the south 

edge of Clifton Flat. Both the topographic and the 

stratigraphic throws decrease in this direction, but the 

latter cannot be quantitatively evaluated here. The 

fault cannot be recognized on the north side of the flat 

and presumably dies out beneath it. South of the 

quadrangle the fault must continue for many miles 

along the eastern front of the Deep Creek Mountains. 

The southern part of the Deep Creek Mountains as 

included within the quadrangle is thus composed of 

an uplifted block bounded on each side by a depressed 

block. Northward this structure passes into a tilted 

block by the dying out of the eastern boundary fault. 

The uplifted block to the south is, in one sense, a horst. 

Strictly considered, however, it is not, for the two 

faults on its sides are very probably of different ages, 

the eastern fault being the older. This conclusion is 

reached by a consideration of the position of the divide, 

which is more than 3 miles from the eastern fault and 

less than 2 miles from the western fault. On the east 

side, moreover, the range is fronted by the resistant 

Prospect Mountain quartzite. It is therefore rather 

certain that the eastern fault was the earlier, because 

there must have been time for the consequent drainage 

along it to cut back through harder rocks, nearly twice 

the distance that the streams have cut across the 

western fault. 

The second of the two major faults on the east side 

of the mountain area that balance the fault on the 

west side must follow the eastern boundary of the 

quadrangle closely. There is no stratigraphic evidence 

for this fault, but there are two physiographic features 

that seem to require it. One is the linear character 

of the mountain front south of benchmark 4767 on 

the Lincoln Highway, which is continued, south of the 

hiily region, by the line of outcrops in the southeast 

corner of the quadrangle and beyond. The other is a 

deformation of the old erosion surface west of the 

supposed fault. As this is traced southward from 

its exposures around Gold Hill, it is seen to be gradually 

tilted to the west. The tilting must have been accomplished by an elevation of the east side while the west 

side, as represented by the surfaces bordering Clifton 

Flat, remained stationary. The maximum tilt appears 

to have been in the latitude of Montezuma Peak, 

which rises more than 1,000 feet above the undeformed 

surface. The course of Rodenhouse Wash offers strong 

confirmatory evidence for such a tilting. The decrease 

in tilting to the south corresponds to the approximate 

point of termination of the fault south of Overland 

Canyon, which therefore is en echelon 'with the one 

now being discussed. 

The basinlike depression of Clifton Flat appears to 

have resulted from the movements along the three 

faults just described. The flat is bordered on the east, 

south, and west by high lands; on the north, however, 

it is continuous with the much dissected old erosion 

surface. Apparently the border faults east of Montezuma Peak and west of Ochre Mountain were so far 

apart that the tilting of the surface which accompanied 

the faulting affected only slightly or not at all the 

region now occupied by the depression. 

The old surface to the BOuth was uplifted by means 

of the southern of the two eastern border faults. The 

present outlines of the basin are apparently due to the 

difference in age between the eastern and western 

border faults. The southern of the two eastern faults 

is clearly older than the western one, and, as the northern fault has en echelon relations with the southern, 

it too is presumably older than the western fault. .As 

a result of this earlier faulting, a drainage channel 

appears to have formed· extending westward from 

Montezuma Peak. 

With the initiation of movement along the western 

border fault, this drainage channel kept pace with the 

gradual elevation of the block east of the fault by an 

equally rapid excavation of its bed, before the process 

was terminated by the headward erosion of Overland 

Canyon. Before this event happened, however, about 

1,000 feet of rock must have been removed at the site 

of the present pass through which the Lincoln Highway 

-~~~--~ ~~~~~~~~~~.----~ =~---------------------
GEOLOGIC 63 

descends into the valley of Deep Creek. The net reBUlt was to give the depression its present roughly 

triangular shape rather than the linear shape with 

northward drainage that it would have possessed if 

the three faults had been exactly contemporaneous. 

The recent normal faulting in the northern third 

of the quadrangle is entirely distinct from that just 

described. This is indicated by the presence in the 

latitude of the Gold Hill town site of remnants of the 

old surface at accordant altitudes from the eastern 

border of the quadrangle almost to the western border. North of this zone several of these faults have 

been recognized. .. Movement along the most easterly fault of the 

northern group shown on plate 3 is thought to be the 

cause of the present altitude of Dutch Mountain. 

This fault is wholly concealed by alluvium, and the 

chief evidence of its presence, aside from the drainage 

pattern along the east side of the mountain, is the difference of nearly 2,000 feet in altitude that separates 

the old erosion surface around the town of Gold Hill 

from the summit of Dutch Mountain. The considerable dissection of the east side of Dutch Mountain 

suggests that the fault must be somewhat older than 

that on the east side of the Deep Creek Mountains, 

which also has the Prospect Mountain quartzite on 

the uplifted side. 

The two faults on the west side of Dutch Mountain 

can be shown with more certainty. The more westerly, along the western base of the mountain, bends 

from a southeasterly to an easterly course and appears 

to coincide with an older transverse fault. Remnants 

of the old erosion surface are preserved on the ridges 

east of the fault, and their altitude as compared with 

the altitude of similar remnants on the hanging-wall 

side of the fault near its south end indicate that the' east 

side has been elevated about 500 feet. 

The eastern fault represents renewed movement 

along a portion of the Trail Gulch fault. Several 

bits of evidence testify to its presence-the topographic 

discordance, its influence upon the drainage pattern, 

and the high-level gravel immediately west of the 

fault. The displacement along the fault cannot be 

exactly determined, because the position of the old 

erosion surface in the uplifted block cannot be determined, but the throw must be at least 800 feet. 

The fault in the northwestern part of the quadrangle 

is also thought to follow a line of older faulting. The 

total throw of this fault as determined stratigraphically 

is much too great to account for the present distribution of the White Sage formation, and it is suggested 

that there has been renewed movement whose magnitude may be estimated from the topography on each 

side as from 600 to 800 feet. This suggestion is based 

on the presence, west of the fault, of a postmature 

erosion surface at an altitude of about 5,600 feet, in 

STnUCTURE 

which Deep Creek and its tributaries are entrenched. 

East of the fault the country is considerably dissected, 

but there appears to be no topographic break between 

it and the type area of the old surface around Gold 

Hill. Several of the summits near the fault reach an 

altitude of 6,200 feet, however, and it is thought that, 

in addition to the required depression of about 400 

feet west of the fault, there must have been an elevation of at least 200 feet in the block east of it. The 

sum of these two agrees fairly well with the figures 

indicated by the observed distribution of the White 

Sage formation. 

Gilbert 14 has described even more recent normal 

faulting in the Lake Bonneville beds on the east side 

of the range. This locality was not examined by the 

writer, and the extent of the faulting of this age is not 

known. 

The relatively recent normal faulting shown in the 

Gold Hill quadrangle is not as spectacular as that in 

many other regions in the Great Basin, but the mechanics of the process is seemingly well illustrated. 

The characteristics of the faulting in this quadrangle 

may be summarized as follows: 

1. The faults are by no means contemporaneous. 

2. They exhibit a strong tendency to utilize earlier fault lines. 

3. Displacements along them were accomplished by movements of both the hanging-wall and footwall blocks. 

4. Both elevation and depression appear to have been accomplished by tilting of the affected blocks. At relatively short 

distances away from the fault the tilt is no longer discernible. 

5. They were initiated after a long period of stability, during 

which the surface was reduced to a state of postmaturity. 

6. The faults may terminate abruptly. 

7. En 6che1on relations among the faults are found. 

8. Both curving and straight faults were formed. 

9. Apparent horsts, and presumably also graben, may result 

from two faults of somewhat different ages. 

10. The faults have no obvious relation to the igneous rocks 

exposed within the quadrllngle, being much younger than the 

intrusive quartz monzonite and older than the volcanic rocks. 

During the field work scant attention was given to 

the minor topographic changes that followed the 

normal faulting of this age. Casual observations indicated, however, that the quadrangle contains a wealth 

of material bearing upon the postfault history, and 

that detailed work would produce a great deal of 

information concerning the climatic changes that have 

occurred not only since Lake Bonneville time but also 

in the earlier stages of the lake. 

AGE OF THE STRUCTURAL FEATURES 

The age of the faults and folds formed . during the 

five structural cycles can best be determined by their 

relations to the Lower Triassic limestone, the Eocene 

(?) White Sage formation, and the quartz monzonite 

stock, which was probably intruded in late Eocene or 

H Gilbert. G. K., Lake Bonneville: U.S. Geol. Survey Mon. 1. p. 353. 1890. 
64 GOLD HILL MINING DISTRICT, UTAH

early Oligocene time (p. 48). All the cycles are younger 

than the Triassic, as the Triassic limestone is a unit of 

the nearly conformable stratigraphic column affected 

by the structural disturbances. 

The first and second cycles are older than the White 

Sage formation, as the beds of this formation unconformably overlie both the recumbent anticline that was 

formed in the first stage of the second cycle and the 

normal faults that were active in the second stage. As 

there are no recorded periods of orogeny during early 

Mesozoic time in the eastern Great Basin, the structural features of the first and second cycles may be 

tentatively classed as of Cretaceous or early Eocene age. 

Normal faults that are considered to belong in the 

second stage of the third cycle cut the White Sage 

formation at several places in the northwestern part 

of the quadrangle, and in at least one locality (p. 43) 

there are considerable discordances in dip between beds 

within the formation. These features are thought to 

indicate that the formation was deposited during the 

final stages of the compression that caused the first 

stage of the third cycle, and the faults and fo'ds of 

this cycle are considered to be of Eocene a.ge. 

The structural features of the fourth cycle are 

younger than the White Sage formation but are cut 

off by the quartz monzonite intrusion and must therefore date from late Eocene or early Oligocene time. 

The similarity in strike of the transverse faults of this 

cycle to the minor transverse faults of the fifth cycle, 

which cut the intrusive, suggests that the time interval 

between these two cycles was smalL 

In a recent review of the thrust faults previously 

described in the northern Rocky Mountains, Mansfield 16 notes that "these faults were in all probability 

not synchronous but some occurred later than others. 

This fact indicates that the compressive stresses that 

produced the overthrusts were maintained over a considerable period and that they found relief at more or 

less distinct successive intervals-a conclusion that 

should naturally be expected in view of the greatness 

of the region affected and of the tremendous stresses 

involved." 

The Gold Hill quadrangle appears to be unique 

among those so far mapped in that it exhibits several 

of the successive thrusts. The reason for such a localization of thrusts of different ages in one area instead 

of the ideal sequence of successively younger thrusts 

from west to east postulated by Thom/6 is not clear. 

In contrast to other regions of thrusting, Gold Hill is 

not at or particularly near the limits of earlier sedimentation, and therefore the localization of thrusts 

II Mansfield, G. R., Geography, geology, Ilnd mineral resources of part of south. 

eastern Idaho: U.S. Oeol. Survey Prof. Paper 152, p. 383, 1927. 

.. Thom, W. T., Jr., The relation of deep-seated faults to the surface structural 

features of central Montana: Am. Assoc. Petroleum GeologiSts Bull., vol. 7, pp. 1-13, 

1923. 

within the quadrangle cannot be ascribed to the influence of "initial dip," as has been done in other 

areas. A possible explanation of this sort might be 

considered to lie in the presence immediately to the 

east of Schuchert's positive area, "Utah." 11 

The writer, however, is more inclined to regard the 

thick Pennsylvanian sedimentary prism in the Oquirrh 

Mountains 18 as the most important factor. Rocks of 

this age are so much thinner within short distances 

both to the east and west that there must have been 

a marked original depositional syncline. Initfation of 

compression from the west would tend to increase the 

synclinal fold and permit overriding by the thinner 

sedimentary colUInn to the west. Successive periods 

of compression would only accentuate the syncline, 

and thrusting would thus be localized in the zone 

immediately to the west. 

The age of the relatively recent normal faulting cannot be definitely fixed. Gilluly 19 has recently summarized the evidence at hand regarding the age of 

faulting of this type in the Great Basin region. He 

notes that the initiation of faulting appears to differ 

in different regions. He concludes that in the Oquirrh 

Range the faults now expressed by the present topography probably became active at some time between 

the Oligocene and the upper Pliocene. In the Gold 

Hill quadrangle the direct evidence consists in the 

observations that the faulting is younger than a mature 

erosion surface developed upon both the sedimentary 

rocks and the quartz monzonite and is older than the 

volcanic rocks and is also probably older than the 

Pliocene (?) sediments. As the age of the Pliocene (?) 

formation is purely speculative, it has no immediate 

bearing upon the age of the faulting. The writer prefers the younger of the two ages set by Gilluly for the 

inception of the Gold Hill faulting, because of the fact 

that time must be allowed for the exposure of the late 

Eocene or post-Eocene quartz monzonite by erosion 

and the development upon it of a mature erosion 

surface. 

LOCAL DESCRIPTIONS 

To facilitate the description of individual features, 

the quadrangle has been divided into six structural 

blocks. The extent of these blocks is indicated on 

plate 3, where it may be seen that the dividing lines 

between blocks, except those outlining the quartz 

monzonite, are major structural features. The accompanying correlation table summarizes the structural history of each of the blocks and indicates the 

contemporaneous features. 

17 Schuchert. Charles, P!IIeogeography of North America: Geol. Soo. America 

Bull., vol. 20, p. 474. 1910. 

18 Gilluly, James, Geology and ore deposits of the Stockton and FaIrfield quadrangles, tTtah: U.S. Gool. Survey Prof. Paper 173, pp. 34-38, 1932. 

It Gllluly, James, Basin Range faulting along the Oquirrh Range, Utsh: Geol. 

Soc. America Bull., vol. 39, pp. 1118-1120, 1928. 

r 

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 17, PLATE 6 

A. EAST SLOPE OF OCHIm MOUNTAIN. B. DISSECTION ON WEST SLOPE (W OCHHE MOUNTAIN. 

C. DISSECTED POSTMATURE EROSION SURFACE, D. DISSECTED POSTMATURE EHOSION SUIU'ACE. 

Looking IlOUtheast from a point near U.S. locating monument 11. Looking east from a point n~,ar the Yellow Hammer mine. 

All photographs by F. A. Melton.. 

~ 
U.S. GEOLOGICAL SUHVEY PRO}<'ESSIONAL PAPER 177 PLATE 7 

A. CRUMPLING BENEATH NEARLY FLAT F'AUl:r ON WEST SIDE OF OCHRE MOUNTAIN. B. PLUNGING .MINOR ANTICLINE IN THE MANNING CANYON FORMATION. 

C. VARIABLE DIP OF FAULT BETWEEN THE MADlSON LIMESTONE AND THE WOODMAN D. MINOR THRUST IN THE WOODMAN FORMATION NORTH m' THE GAIUlISON 

FOHMATION IN ACCIDENT CANYON. MONSTER NEW CAMP. 
Correlation of stnwtural feature8 in Gold Hill quadrangle 

Cycle and stage 1 Deep Creek Mountain blook Uiyab! Canyon block Ochre Mountain block Dutch Mountain block Northwestern blook 

Not represented? 

First. I-;~~;~;;JI:.-~~;-::~~;_______ II_:~~~:;;'~_) -~:~;;;~~:~l'-:;;;;;;::;~~;,;;.;;j-I-N~i-~~~~;;;d'------

transverse faulting. 

movement on eastern border fault. 

Pass thrust 

subsidiary 

West-northwest trans­ verse faulting. 

Normal faulting. 

Second stage. Northeasterly fault on Blood Mountain. 

I 

I i 

First stage. 

Second. 

Major anticline. 

West-northwest 

Second stage. 

Normal faulting. Early 

IFI......... 

Third. 

North 

and 

thrusts. 

East-west Blood Canyon and Dry CanFirst stage. yon faults. 

Mmor thrusts and reverse faults. 

Fourth. 

Second stage. I Not represented? 

Uiyabi Canyon? Abundant. faults. I ~~~~------

Major anticline. Major folding? Major folding. I Recumbent anticline 

and other folds. 

West-northwest Transverse faulting. Dutch Mountain 

transverse fa u It­ thrust and minor 

ing. thrusts. 

I Normal faulting. Normal faulting. Normal faulting. Trail Gulch and Bar 

Trail Gulch fault and Creek normal faults. 

northwest faults. 

~-----------+-------------~-------------I,--------------r-----------

Normal faulting east 

of benchmark 

5868. 

Blood Canyon trans­ verse fault. 

Minor reserve faults. 

Warping of North 

Pass thrust. 

Not represented? 

Transverse faulting. 

Ochre Mountain 

thrust and subsidiary thrusts. 

Normal faulting, es­ pecially along old­ er faults. . 

East-west transverse 

faults. 

East northeast faults. 

Not represented? 

Pool Canyon trans­ verse fault. 

Ochre Mountain thrust 

and subsidiary thrusts. 

Reversal of movement on Trail Gulch fault. . ------------------------------~ 

Normal faulting rare. 

Minor thrusts? 

Warping of axial plane 

of recumbent anticlinei' 

t --. ----------------------------­ I Normal faulting of 

northerly strike? 

Conjugate faults. verse fault and re­ lated conjugate faulting. 

Garrison Monster transSmall normal faults? Not represented?

Quartz monzonite block 

1­

~ g 

e 


<":l 

~ l!'j 

Fifth cycle and faulting I Not represented? Not represented? Faults related to the I Not represented? Not represent.ed? Normal fa ult s re­ related to the quartz quartz monzonite.

monzonite. 

lated to intrusion. 

East-west transverse 

faults and minor 

thrusts. 

Small faults related 

to cooling of intrusive. 

Late normal faulting. East and west border E1lISt and west border I West border fault. Normal faulting in part Renewed movement 

faults. faults. along older faults_ along north-south 

fault. 

C» 

en 

l 
66 GOJ,D HILL MINING 

Evidence for the separation of thtr structural history 

into five epochs is given in the following pages. It is 

far from being as conclusive as might be desired, and 

future more detailed study may result either in the 

elimination of some of the five epochs or in the addition 

of others. Some of the structural features could not be 

definitely assigned to specific epochs, because their 

relations to features of known age could not be determined, and on plate 3 it WQ,S necessary to correlate 

them on the basis of their similarities to features for 

which more definite information was available. The 

difficulty of correlation is increased by the evidence of 

recurrent movements along some of the faults and by 

the impression that such movements may have been 

widespread; however, in spite of the uncertainties 

regarding individual features and the exact correlation 

of structural epochs, it is clear that deformation in this 

region has taken place in recurrent cycles and has 

continued over a long period of time. 

DEEP CREEK MOUNTAIN BLOCK 

The Deep Creek Mountain block includes that portion of the 

quadrangle south of the Blood Canyon transverse fault and thus 

includes the southern extension of the Cliftoll Hills as well as 

the Deep Creek Mountains. 

The structure in this block is simpler than in any other part 

of the quadrangle. The pre-Carboniferous beds make up the 

westward-dipping limb of an anticline formed during the second 

structural cycle and bounded both on the east and west byrecent 

normal faults. The continuity of the beds ia broken by three 

rather large transverse faults of different ages, in addition to 

the one that limits the block on the north. Several minor 

normal and. transverse faults and several small thrust faults 

have been recognized. Section P-P' on plate 1 illustrates the 

monoclinal character and shows two of the minor thrust faults. 

Near the northern boundary fault simplicity of structure is 

replaced by complexity, and several thrust plates that underlie 

the North Pass thrust may be recognized. These features are 

illustrated in the eastern part of section J-J'-J". Overturning 

along low-angle transverse faults is found in the Carboniferous 

area to the northeast (sec. H-H'). 

Dry Canyon transverse fault.-The southernmost transverse 

fault follows more or less closely the course of Dry Canyon on 

the east side of the mountains and Simonson Canyon on the 

west side. Its dip was not measured directly, but subsidiary 

parallel fractures dip 80°-85° N. The fault is poorly exposed 

throughout its extent. Where it cuts through shale and thinbedded limestone the fault plane is covered by talus, and in 

its course through the more resistant dolomite and quartzite 

these rocks are so shattered, bleached, and recrystallized that 

in most places it is impossible to recognize the actual fault contact. The bleaching and recrystallization are probably in part, 

at least, the result of igneous metamorphism, for a small body 

of a sheared intrusive igneous rock was found along the fault 

just west of the spring near the mouth of Dry Canyon. The 

apparent displacement is somewhat variable, because of variations in dip on the two sides of the fault. The presence of 

thrust faults on both sides and the character of the drag shown 

on the south side of the fault on the divide render it probable 

that the greater part of the displacement was horizontal, the 

north side moving toward the east. The amount of horizontal 

movement was close to 1,000 feet. Outcrops west of the ridge 

linc are offset more than twice this distance, owing to the com~ 

bination of west dips and the steep slope. 

DISTRICT, UTAH 

Minor fauUs south of Dry Canyon transverse fault.-Inthe 

prospect tunnel south of the mouth of Dry Canyon a fault zone 

is exposed that strikes nearly north and dips 65°-90° W. Prospect Mountain quartzite forms both walls, but on the east the 

quartzite dip3 to the east at moderately high angles, and on the 

west it is slightly inclined to the west. The fault has normal 

relations, as the thickness of the eastward-dipping quartzite 

is in excess of that exposed to the west. There is a parallel 

shear zone about 100 yards to the west. 

Half a mile west of these normal faults there are two rather 

similar faults that strike west of north and dip to the east. The 

eastern one strikes N. 16° W. and dips 50° E. It drops the upper 

contact of the Prospect Mountain quartzite about 75 feet. The 

throw decreases northward along the two branches of the fault 

in the gulch south of Willow Spring. The Dry Canyon fault 

is offset by both branches. The western fault has about the 

same strike and dip, but its displacement is considerably greater, 

probably being more than 400 feet where it crosses the ridge. 

This fault also offsets the Dry Canyon fault, but north of the intersection the normal fault can be recognized for only a short dis~ 

tance, beyond which the beds of the Busby quartzite are sharply 

warped, the more easterly outcrops being thus relativelydepressed. 

There must be additional faulting on the Cabin shale in this 

region, for exposures of the formation not affected by either of 

the two normal faults are only 100 feet or less in thickness. 

Locally also the bedding strikes at right angles to the underlying 

quartzite. These features are thought to indicate the presence 

within the shale of a low-angle fault, which is probably related 

to the transverse fault. 

A minor fault in the southern branch of North Pass Canyon 

is indicated by a displacement of 200 to 300 feet of the outcrops 

of the resistant Lamb and Hicks dolomites. It was proba.bly 

formed at the same time as the large transverse fault in Dry 

Canyon, but it could not be traced into that fault through the 

poorly exposed beds of the Abercrombie formation. Subsidiary 

fractures parallel to it strike N. 70° E. and dip 75° S. This is 

probably the strike and dip of the fault itself, but the fault 

plane was not exposed. 

Two other faults were found south of the main transverse 

fault. These are on the west side of the range, in the southern 

branch of Simonson Canyon. The easterly fault strikes about 

N. 45° W. and dips steeply to the southwest. It brings various 

beds of the Laketown dolomite into contact with the Fish Haven • 

dolomite and the Chokecherry dolomite. The western fault 

brings the Sevy dolomite into contact with the Laketown dolo~ 

mite. The two faults are exposed for only a short distance 

within the quadrangle. Their continuation to the north is covered by the gravel in the canyon bottom, but they must be cut 

off by the Dry Canyon fault. 

SlJ,vy Canyon transverse fauU.-The transverse fault in Sevy 

Canyon has a west-northwesterly strike, in distinction to the 

nearly east-west strike of the Dry Canyon fault to the south. 

As a result the two are only a mile apart on the east side of the 

range and over 2 miles apart on the west side. The Sevy 

Canyon fault has a pronounced northerly dip over much of its 

course, as may be seen on the steep slopes on the south side of 

North Pass Canyon. Parallel fractures dip 60° NNE. The 

drag shown by thinner-bedded formations cut by the fault, 

especially the Cabin shale, and the distribution of fragments in 

shatter zones indicate that the movement was chiefly horizon~ 

tal, the south side moving relatively to the east. The offsetting of formations along the fault increases rather regularly 

westward. Thus outerops of the Cabin shale are shifted about 

600 feet, the Young Peak dolomite about 1,200 fect, the Fish 

Haven dolomite about 2,000 feet, and the Guilmette formation 

about 4,000 feet. This variation is in part the result of subsidiary thrust faults and in part the result of a steepening in 

the westward dip of the bedding on the south side of the fault 
GEOLOGIC STRUCTURE 67 

but not on the north side. A minor fault of similar strike 

occurs a short distance to the north and was probably formed 

at the same time. 

Relation of Sevy Canyon fault to Dry Canyon fault.-The age 

of the Sevy Canyon fault relative to the Dry Canyon fault is 

not obvious. It is probable that the northwestward-striking 

Sevy Canyon fault is the older, for faults of similar strike 

apparently terminate against the east-west Dry Canyon fault 

and against the parallel Blood Canyon fault, to the north. 

Contemporaneity of the two faults cannot be disproved, however, as the contact between them is not exposed, but, inasmuch 

as crumpling ill the rocks between the two faults to the east 

might be expected if they were of the same age, the absence of 

crumpling suggests that the Sevy Canyon fault is of similar age 

to the other northwesterly transverse faults. 

Minor fault8 between the Dry Canyon and Sevy Canyonfaults.­

On the ridge between Dry Canyon and Sheep Canyon the 

Abercrpmbie formation is 700 feet thinner than on the ridges to 

the north or south. A zone of disturbed strikes and dips in the 

saddle west of peak 7423 on this ridge is thought to be the site 

of the fault movement. The beds are thought to have been 

cut out by overriding rather than by normal faulting, because 

the beds east of the pass dip more steeply (40°-50° W.) than 

normal, whereas those to the west dip less steeply (25°-30° W.). 

Such drag effects are not characteristic of normal faulting but 

may be the result of thrust faulting. The fault was not traced 

to the north or south because of poor exposures on the hillsides, 

but it must die out to the north, for on the ridge north of Sheep 

Canyon the Abercrombie formation has its normal thickness. 

It probably terminates southward against the Dry Canyon fault. 

This inferred thrust fault is shown on section P-P', plate 1. 

The northwesterly fault that is cut off by the Dry Canyon 

fault near the head of Dry Canyon is traceable with difficulty, 

because of shattering andrecrystallization for some distance from 

the main fault. Its presence is required by an offset in the outcrop of a characteristic bed near the top of the ChOke-cherry dolomite. It is apparently terminated on the west by a thrust fault 

exposed on the divide. The thrust fault strikes about north and 

dips rather steeply to the west. It has caused beds near the middle of the La.ke'town dolomite to override the lower beds of the Sevy 

dolomite, involving a repetition of about 600 feet stratigraphically. 

(See sec. P-p'.) Toward the north, the strike of the thrust changes 

to northwest, the dip steepens and inclines to the southwest, and 

the fault is indistinguishable from other minor transverse faults. 

A sornewhat similar thrust fault is found about a mile to the 

north, on the south slope of peak 8291. Here, however, the 

thrust has not caused a duplication of strata but has eliminated 

more than half of the normal thickness of the Laketown dolomite. The line of the fault is marked by a zone of crushed 

dolomite and· poor exposures near the base of the formation. 

The fault must die out to the south, for it was not recognized 

south of the head of the canyon, where the Laketown dolomite 

has its full thickness. To the north the strike swings to the 

northwest, the dip steepens, and the apparent displacement 

increases, as Sevy dolomite and Simonson dolomite south of 

the fault are successively brought. into contact with beds of 

Laketown dolomite north of the fault. At an altitude of about 

7,000 feet in .Bevy Canyon this fault meets the Sevy Canyon 

fault. The increased apparent displacement is probably an 

actual increase, because overriding by massive beds in the 

Simonson dolomite may be observed in the region where the 

fault changes its strike to northwest. 

Blood Canyon transverse fault.-The transverse fault in Blood 

Canyon, which limits the Deep Creek Mountain block to the 

north, has a rather sinuous course, which averages close to eastwest and thus makes an angle of about 25° with the older northwesterly transverse faults. Its dip is also variable. West of 

Blood Canyon it is· steep either to the north or south, but to the 

east the fau.lt has a moderately low south dip. East of Overland Canyon the fault cuts through an area in which metamorphism has partly or completely concealed many of the minor 

structural features connected with the fault. Adjacent to the 

more easterly mile of exposure of the fatllt the Oquirrh formation 

to the south is complexly folded on a small scale, although away 

from the fault the formation has a rather uniform eastward dip. 

Structure in Sevy Canyon SQuth of the Blood Canyon fauU.­

The most striking structural feature in this region is the pronounced northeasterly strike of the formations near the Blood 

Canyon fault. Very little crumpling or folding is observed in 

. the beds except on the extreme western flank of the range, 

where beds of the Guilmette formation are compressed into 

several small close folds, Beds on each side of the Blood Canyon fault are badly shattered, and in most places the fault 

cannot be exactly located, but where it forms the northern 

boundary of the large outcrop of the Woodman formation a 

thick breccia zone is exposed, dipping almost vertically. 

North Pass transverse fault.-The North Pass transverse 

fault, striking northwest, terminates the linear outcrops of 

Prospect Mountain quartzite, Cabin shale, and Busby quartzite 

that extend to the south boundary of the quadrangle. North 

of the fault are exposed Middle and Upper Cambrian formations 

that are folded into a plunging anticline. Westward along the 

fault the Young Peak dolomite and Trippe limestone are but 

little offset. This portion of the fault, therefore, marks a rather 

local line of diIferential movement, the beds south of the fault 

showing a more or less uniforin westward dip, and those to th e 

north being folded to form an anticline. The westward continuation of the North Pass .fault again shows a considerable 

displacement, as the fault in this region marks the southern 

limit of a number of thin overthrust plates. The fault is cut 

off to the northwest by the Blood Canyon fault. It may be 

traced beneath gravel some distance to the east, however, by 

reason of the isolated outcrops east of the main range. 

Major anticline along east front of range.-The plunging anticline in North Pass Canyon that is terminated southward by 

the transverse fault is thought to be a continuation of a major 

anticline whose axis appears to be nearly coincident with the 

eastern front of the range. The axis is covered by gravel in 

most places, but eastward dips in the Prospect Mountain quartzite south of Dry Canyon a~d nearly horizontal bedding in a 

down-faulted exposure of higher Cambrian beds half a mile 

north of the mouth of Sheep Canyon allow it to be located 

with moderate accura«y. 

If the two fl,nticlines are the same, their present positions 

imply that the south side of the eastern segment of the North 

Pass transverse fault has moved relatively eastward and upward. 

Thru8t plate8 on the north side of North Pas8 Canyon.-The 

anticline in North Pass Canyon has affected only the Middle 

Cambrian portion of the section. The Upper Cambrian Lamb 

dolomite is not folded but erlends across the anticlinal axis 

without regard for the underlying structure. ' The lower contact 

of the dolomite is a thrust fault, whose plane is irregular and 

which shows a strong tendency to be at a higher altitude where 

the underlying strata are resistant and at a lower altitude 

where they are weak. The dolomite beds, although they retain 

their characteristic lithology, are thoroughly shattered in the 

whole overriding mass, but the underlying beds are comparatively little affected. The map shows clearly the disappearance 

beneath the thrust plate on the west and the emergence on the 

east of the folded Young Peak dolomite and the Trippe limestone, and this feature is easily recognized in the field. The 

occurrence of a small patch of dolomite undoubtedly belonging 

to the Lamb dolomite above the Trippe limestone on the 

eastern flank of the anticline suggests that this overriding plate 

had only a small extent, and this is borne out by features 

farther east. 

There are several other thrust plates above that of the Lamb 

dolomite. The mudl patches of the Hicks formation and the 
68 GOLD HILL MINING DISTRICT, UTAH 

Chokecherry dolomite extending northward from North Pass 

Canyon are not easily delimited but are certainly present 

because of their characteristic lithology and, in the Hicks, characteristic fossils. Their 'boundaries to the east and west are 

thought to be thrust faults. To the west is a somewhat larger 

thrust plate of Laketown dolomite, which contains recognizable 

and characteristic fossils. This plate is offset by a transverse 

fault, which is fairly well exposed on the south slope of peak 

7660. North of the transverse fault the overthrust plate of 

Laketown dolomitCil extends nearly 2,500 feet farther east and 

rests upon the overriding plate of Lamb dolomite. It is in turn 

overlain by dolomites similar in lithology to those in the 

Simonson dolomite. 

North Pass thrust and minor related thrusts east of North 

Pass Canyon.-The North Pass thrust crops out at only one 

locality in the block east of North Pass Canyon. At two other 

places it may be located rather closely, however, and a true 

measure of its extent may be obtained from the exposures of 

the central facies of the Carboniferous rocks tbat lie above it. 

The only exposure of the thrust is found half a mile north of 

hill 6267, southwest· of Blood Mountain. Here thin-bedded 

strata of the Oquirrh formation rest upon thoroughly breccil\ted 

fossiliferous Laketown dolomite. The contact betweeI). the two 

is a thrust dipping about 10° N., which is exposedfo:r only a 

short distance before being terminl\ted to the west by gravel 

and to the east by a younger normal fault. 

The Laketown dolomite beneath the thrust is oply 100 feet 

thick and rests upon limestones lithologically identical wi.th 

those of the Guilmette formation. Thefault. contlj.ct between 

the two parallels the North Pass thrust above. This 100-foot 

slice of Laketown dolomite is considered to be the eastward 

continuation of the thrust plate of the same formation that was 

found in North Pass Canyon, where it rests upon a similar 

thrust plate of Lamb dolomite. 

The main thrust may also be located rather closely on the 

south side of Blood Mountain. Just south of the road fork at 

an altitude of 5,854 feet there is an outcrop of brecciated 

fossiliferous Laketown dolomite, identical with that underlying 

the thrust half a mile to the northwest. Outcrops of the 

Oquirrh formation are found to the east, north, and west; and 

the North Pass thrust almost certainly is concealed by the 

intervening gravel. ·The thrust may also be approximately 

located for nearly a mile south of this region, for the six small 

outcrops of the Oquirrh formation south of hill 6267, as well as 

the beds at the base of the hill, are shattered, brecciated, and 

in some places dolomitized, suggesting that the thrust is not 

far beneath.. 

The remaining region in which the thrust may be recognized 

is in the southeast corner of the quadrangle, where there are 

several outcrops entirely surrounded by gravel. The largest 

and most westerly of these outcrops is composed of brecciated 

beds of the Oquirrh formation, which have been extensively 

silicified and dolomitized. The three small eastern outcrops are 

equally brecciated but are made up of dark dolomites similar 

to those in the Guilmette formation and the Simonson dolomite. 

In the northern outcrop were found unbroken fragments that 

contained the large brachiopod Stringocephalu8 burtoni, which 

is characteristic of these formations. On the map the three 

exposures are shown under the symbol for the Guilmette formation, but it is not improbable that beds belonging to the Simonson dolomite are present. The contact between the Devonian 

and Pennsylvanian strata is concealed, but it seems certain, 

because of the extensive brecciation and the stratigraphic 

relations, that this contact is a continuation of the North Pass 

thrust. 

Eastern border fault.-There is evidence from several sources 

that a normal. fault of considerable throw must parallel the 

east front of the Deep Creek Mountains. The physiographic 

evidence of faulting has been noted on pages 61-62 and indicates 

a throw of about 2,000 feet. The stratigraphic evidence is 

conflicting: in part it indicates a throw of 2,000 feet, checking 

the physiographic evidence, and in part it suggests a displacement of 6,000 feet. These contradictory results are explained 

by the fact that the 2,OOO-foot throw is based on beds above 

the North Pass thrust, and the 6,000-foot throw on beds beneath 

the thrust. There have therefore been two periods of activity 

along the fault, the first preceding the thrust and the second 

following the thrust. 

Two groups of outcrops provide a measure of the movement 

preceding the thrust. One of these is about half a mile north 

of the entrance to Sheep Canyon, where a crescent-shaped outcrop of thoroughly brecciated limestones and dolomites is found 

only 1,000 feet east of the mountain front. These beds have 

been mapped as the Abercrombie formation and the Young Peak 

dolomite, respectively, because their lithology is characteristic 

of those formations. The contact between the limestone and 

the dolomite has a very gentle dip and apparently is close to the 

axis of the major anticline. The stratigraphic interval between 

these beds a.nd the Prospect Mountain quartzite immediately 

to the west is 6,000 feet. 

The second group of outcrops includes those in North Pass 

Canyon northwest of hill 6267. These are composed of gray 

and black laminated dolomites that are identical with beds in 

the SimOllson dolomite. The two northwesterly outcrops dip 

25°-90° E. and are less than a quarter of a mile from beds of 

the Abercrombie formation that ha.ve gentle eastward dips. 

The stratigraphic interval between the two formations is again 

6,000 feet, and the only fault that could reasonably come between them is the eastern border fault. Incidentally, the difference in stratigraphy on the east side .of the fault between this 

region and that to the south shows that the North Pass Canyon 

transverse fault continues east of the border fault. 

The best stratigraphic measure of the movement along the 

eastern border fault after the thrust is provided by the 100_ 

foot slice of Laketown dolomite lying beneath the North 

Pass thrust. This was correlated with the similar thrust 

plate west of the border fault, and by projecting both plates to 

the fault line, the throw is seen to be 2,000 feet (sec. JI_JH), 

thus checking the physiographic .evidence. 

The fault plane itself is exposed only along the divide between 

North Pass Canyon and Blood Canyon. In this region the 

fault splits into two branches, both of which offset the Blood 

Canyon transverse fault. The throw along the westerly branch 

is comparatively small, amounting to about 300 feet; the easterly 

branch has a greater throw, but it cannot be directly measured 

in the vicinity of the outcrops, as the North Pass thrust underlies the beds to the east but has been eroded west of the fault. 

Minor 8tructuralfeatures on Blood Mountain.-A normal fault 

following the west side of Blood Mountain offsets the Blood 

Canyon transverse fault about 1,200 feet. The transverse fault 

has a considerably lower dip at this point than in the region to 

the west, and it is believed that the large offset reflects this low' 

dip. The normal fault must die out southward if the inferred 

position of the North Pass thrust southeast of hill 6267 is correct. 

The northeasterly fault cutting through the crest of Blood 

Mountain has a throw of about 400 feet, measured by the position of a thick limestone bed on each side. This fault branches 

to the north, and the western branch is cut off by the Blood 

Canyon fault. A fault with similar strike to the southwest, 

which terminates the exposure of the North Pass thrust, must 

have a throw of about the same magnitude, to judge from the 

altitude of the thrust on each side of it. 

The Pennsylvanian sandstones and limestones that underlie 

Blood Mountain show numerous discontinuous folds. In sec. 

tion J'_JH a syncline is shown just east of the fault, but this 

feature cannot be traced much beyond the line of the section, 
· GEOLOGIC 69 

and in fact it is replaced by a minor anticline to the north. 

The irregular folding is probably due to the North Pass thrust, 

which underlies the mountain at no great depth. 

Faults east of Overland Canyon.-South of the eastern portion 

of the Blood Canyon transverse fault several faults have been 

recognized. Most of these are of minor importance, and only 

two seem to warrant special description. These are the two 

faults with west-northwesterly strike at the south end of the 

Clifton Hills. Both have low dips to the south-the northern 

one, less than 30°; the southern, about 45°. (See sec. H-H'.) 

In both faults the beds on the southern or hanging-wall side 

are bent into local overturned folds. They are thus similar 

to the eastern portion of the Blood Canyon fault and are considered to represent older transverse faults. The northern of 

these two faults is both cut by and cuts off minor normal faults. 

Mutual relations of the structural features.-The first recorded 

structural event in the Deep Creek Mountain region was the 

initiation of compressive forces from the west-northwest. These 

forces resulted in the formation of the transverse faults striking 

in that direction and in the anticlinal fold along the east front 

of the range. Then came a period of relaxation, expressed by 

4,000 feet of the 6,000 feet total throw along the eastern border 

fault. These features are believed to belong to the second structural cycle. Renewed compression from the same direction 

as before resulted in the formation of the North Pass thrust and 

the associated thrust plates exposed in North Pass Canyon. 

After the second compressive movement a second period of 

normal faulting ensued, as shown by the northeasterly fault on 

Blood Mountain, which cuts the thrust plates and is cut off 

by the Blood Canyon transverse fault. These thrusts and normal faults are correlated with the third structural cycle. 

A third renewal of compression, considered to mark the fourth 

cycle, is indicated by the Blood Canyon and related east-west 

transverse faults. It seems probable that minor thrusting occurred in this period also, for minor thrust faults are apparently 

associated with the Dry Canyon fault, which belongs to this 

period. 

The final episode in the structural history of this block resulted 

in the late normal faulting that has largely produced the present 

topography. The eastern border fault is the most resdily 

studied of these faults and shows that some of them at least have 

had a rather complex history. 

UIYABI C.A.NYON BLOCK 

The southern boundary of the Uiyabi Canyon block is the 

Blood Canyon transverse fault, already described. The northern boundary, west of Clifton Flat, follows the parallel transverse fault on the south side of Ochre Mountain. East of 

Clifton Flat this fault continues for only a short distance, and 

the boundary in this region is marked by three large faults, as 

shown on plate 3. 

The block is underlain almost entirely by Carboniferous 

rocks, chiefly of the central facies of the Oquirrh formation. In 

the pass through which the Lincoln Highway descends to the 

Deep Creek Valley these rocks are thrust over contorted Devonian limestones and dolomites, and it is probable that this 

relation holds true for the whole block. The thrust is considered 

to be the North Pass thrust (sec. J-J"-J'). Along the western 

margin of the mountains, on the other hand, Devonian strata 

are locally thrust upon the Pennsylvanian along faults that 

are thought to be younger than the main thrust (sec. 0-0'). 

The Carboniferous beds are folded into a broad anticline whose 

axis is probably close to the west side of Blood Canyon. > West 

of the anticlinal axis the Pennsylvanian beds have been bent 

into discontinuous folds, but east of the axis the beds have a 

uniform eastward dip averaging about 25°. Normal faults of 

several ages are found throughout the block. A transverse 

fault at the northern border of the block (sec. J-J") is accomSTRUCTURE 

panied by warping, and a higher thrust plate is exposed in one 

of the downwarped portions (sees. L-L' and I-I'). 

Minor structural feature8 between Christiansen and Sheridan 

Gulches.-On .the north side of Christiansen Canyon a reverse 

fault striking nearly due north and dipping steeply to the west 

has thrust Devonian beds over the Oquirrh formation (sec. 

0-0'). West of the main thrust are two minor faults that 

strike northwest and are marked by wide breccia zones. The 

Devonian rocks are closely folded and are locally overturned, 

as is clearly shown by the contact between the Guilmette formation and the Simonson dolomite near the western extremity 

of the spur. 

A northwesterly transverse fault east of this area of folded 

and thrust Devonian rocks separates beds belonging to the 

central facies of the Oquirrh formation from gently folded beds 

of the. Guilmette formation, upon which rests a small patch of 

the Woodman formation that belongs to the eastern facies. 

The fault is terminated at the southeast by the Blood Canyon 

transverse fault, which, east of the intersection, forms the 

boundary between the two facies. As the central facies of the 

Carboniferous rocks are found in the plate above the North 

Pass thrust and the eastern facies in the overridden mass, 

this transverse fault in Christiansen Gulch marks the southern 

boundary of the North Pass thrust plate. The North Pass 

transverse fault (p. 67) has similar relations and a parallel 

strike, and it is therefore suggested that the two northwesterly 

transverse faults are segments of the same fault which have 

been offset by the Blood Canyon fault. 

Direction and amount of movement along the Blood Canyon 

fauU.'-:"'The' correlation of the transverse fault in Christiansen 

Gulch with the North Pass transverse fault provides a measure 

of the amount of movement along the Blood Canyon fault. 

The two segments indicate that the rocks south of the Blood 

Canyon fault have moved about a mile eastward, relative to 

those on the north side. Several features appear to corroborate 

this conclusion. The direction of the movement appears to be 

confirmed by the drag effects along the Blood Canyon fault, 

particularly as shown by the fault east of hill 6526, north of 

Blood Canyon, and by the drag folds along the most easterly 

exposures of the Blood Canyon fault. 

The eastern limit of minor folding in the Oquirrh formation 

on both sides of the Blood Canyon fault is also offset in the same 

direction and in roughly the same amount. North of the fault 

the minor folding dies out east of hill 7511, at the head of Blood 

Canyon; to the south, it dies out on Blood Mountain. 

The fact that many of the other structural features found 

north of the fault cannot be recognized in the proper positions 

to the south appears to be a serious objection to the suggested 

displacement. This may be due, however, to either of two 

factors. One is that the late normal faults which cut the Blood 

Canyon fault are so placed that north of the transverse fault 

they duplicate the major earlier normal fault in Blood Canyon, 

and south of the transverse fault, according to the probable 

projections, they conceal it. The second factor is that to the 

north the normal faults are readily apparent by reason of their 

cutting distinctive formations, such as the Ochre Mountain 

limestone and the Manning Canyon formation, but to the south 

the poorly exposed beds are all of the Oquirrh formation, in 

which the detection of faults is difficult, and the evaluation of 

of their displacement, when found, almost impossible. 

Minor thrust east of benchmark 5684 on Lincoln IIighway.-A 

second area of Devonian thrust over Pennsylvanian rocks is 

found about 2 miles north of the locality above described and 

just south of the Lincoln Highway. Here beds of massive 

limestone and dark dolomite containing Cladopora sp. clearly 

overlie the Oquirrh formation above a fault that dips about 

30° NW. The fault is thought to continue north of the highway and to lie between the isolated hills of the Oquirrh formar 
70 GOLD HILL MINING DISTRICT, UTAH 

tion and the main southern spur of Ochre Mountain. The 

limestone is considerably deformed, as are also the thinnerbedded rocks in the spur to the east. The thrust apparently 

terminates against the transverse fault that forms the northern 

boundary of the block. The transgression of this thrust along 

its strike from the Guilmette formation into the Oquirrh formation is thought to indicate that the displacement along it is 

small, and that it, as well as the thrust to the south, represent 

minor thrusts that have cut through the underlying North Pass 

thrust and brought up rocks that normally lie beneath the 

major thrust. 

North Pass thrust.-The North Pass thrust, which must underlie the whole Uiyabi Canyon block, crops out at two places in 

the northwestern portion of the block. In both exposures, 

which are along the Lincoln Highway west of benchmark 6149, 

brecciated dolomites and yellow.'sandstones of the Oquirrh formation rest upon highly crumpled beds of the Guilmette formation (fig. 9). These Devonian beds below the North Pass 

thrust are almost certainly the equivalents of the beds of the 

same age exposed by the minor thrusts described in the preceding paragraphs. 

The North Pass thrust plane must be considerably folded or 

warped, because at a number of places beds of the Oquirrh 

formation crop out at lower altitudes than those at which the 

o 15 Feet L..'--'_-'---'---'----'. 

FIGURE 9.-Crumpling of Guilmette formation 1 mile west of bencbmark 6149, north of Lincoln 

Highway. a, Dolomite; b, sandstone; c, llmestone. 

fault is exposed along the Lincoln Highway. This later deformation is probably the result of the stresses that caused the 

east-west transverse fault that bounds the block on the Rorth. 

Minor folds in Uiyabi Canyon.-Several rather discontinuous 

folds are found in the Oquirrh formation in the western portion 

of Uiyabi Canyon. Two anticlines and a syncline were distinguished, but only one-the western anticline-can be traced 

for much more than a mile, The axis of this fold strikes west 

of north and follows a course that corresponds roughly with the 

ridge line between Uiyabi Canyon and the Deep Creek Valley. 

The western limb of the fold extends down to the valley gravel 

with increasingly steep dips, but the eastern limb has moderately 

low dips and is succeeded east~ard by a shallow syncline. The 

syncline cannot be traced nOr1;hward, and the structure there 

seems to be that of a single broad anticline which plunges to 

the north. The second anticlinal axis is about a quarter of a 

mile east of hill 7009 within piyabi Canyon. This fold also 

cannot be traced to the north, and its place is taken by the 

region of confused dips and minor faulta near hill 6831. East 

of the second anticline, nearly east-west strikes and northerly 

dips are dominant for more than a mile and are succeeded eastward gradually by the north-south strikes and easterly dips 

that characterize the remainder of the district. A generalized 

idea of the folding is given by section 0-0' and the left-hand 

portion of section J'-J". 

Minor faults west and southwest of Clifton Flat.-Minor faults 

of several ages and characters are found in the belt of minor 

folding. In almost everyone the throw is unknown, because of 

the poor exposures and the lenticular nature of the Oquirrh 

formation. Along the west side of the Deep Creek Mountains 

there is a rather distinctive contact between massively bedded 

limestone and dolomite and underlying thinner-bedded rocks. 

By means of this contact the presence of numerous faults can 

be proved. Only one of these faults, along which there is a shift 

of the contact amounting to several hundred feet, has a sufficient displacement to be shown on the geologic map. This is 

the eastward-striking fault that ends near hill 7472. The short 

north-northwesterly fault about half a mile southeast of this 

hill is a small reverse fault with a throw of less than 100 feet. 

The fault of low dip just east of.hill 7194 along the northern 

boundary of Uiyabi Canyon is probably an old normal fault, 

tilted to its present position by later deformation, as it appears 

to have normal relations. It is cut off on the east by a younger 

normal fault, but the faulted segment may be represented by 

an dbscure fault near hill 6831. 

The younger normal fault is probably a continuation of a 

fault of similar strike that cuts the North Pass. thrust along the 

Lincoln Highway. The thrust'is about 100 feet 

lower west of this fault. 

Major anticline south of Clifton Flat.-A major 

anticline affects all the Carboniferous rocks that 

lie in the block above the North Pass thrust, 

Its axis is difficult to trace because of younger 

structural features but appears to trend nearly 

north and to pass beneath the gravel of Clifton 

Flat just east of the entrance to Uiyabi Canyon. 

Several younger normal faults cut the anticline, 

and as a result the oldest formation involved in 

the fold, the Ochre Mountain limestone, is exposed on the eastern flank rather than at the 

core. East of the axis there is "a rather constant 

eastward dip, but west of it the minor folds in 

Uiyabi Canyon are superposed on the older fold, 

although even here the more westerly beds are 

the higher stratigraphically (~ec. 0-0'). 

Normal faulting in Blood Canyon.-On the 

western flank of the major anticline tbe Oquirrh 

formation has been brought into contact at 

two places with the Ochre Mountain limestone by faults 

dipping 30° W. These are believed to be parts of the 

same fault, as the.. recent movement of 2,000 feet along the 

eastern border fault (p. 68), which is exposed between them, 

is of the correct amount to cause the repetition (sec. 0-0'). 

In both of the exposures of the westward-dipping fault the 

normal eastward dip of the Ochre Mountain limestone is 

reversed for a distance of 100 feet or so from the fault. Along 

the eastern exposure a considerable thickness of the Manning 

Canyon formation is found beneath the Oquirrh, but along the 

western exposure these beds are missing over much of the 

distance. 

Transversefault north of Overland Canyon.-The best exposure 

of the trlitllsverse fault north of Overland Canyon is about 1,600 

feet northeast of benchmark 5768. Here dark quartzites and 

black ID1caceous schists that are metamorph!>sed members of 

the Manning Canyon formation abut against massively bedded 

Ochre Mountain limestone. In most places, however, the beds 

northeast of the fault have been engulfed by the quartz monzonite, and the limestone beds to the south are almost untouched. This is but one of several examples of the preference 

shown by the intrusive for following fault contacts during its 

emplacement. The eastward extension of the fault may be 
GEOLOGIC STRUCTURE 71 

approximately located by a belt of jasperoid that almost 

certainly represents a silicification of the fault breccia. The 

transverse fault appears to be cut off by a younger normal 

fault about at its intersection with the road to the Midas mine, 

but the presence in this vicinity of several small areas of 

monzonite makes the exact relations uncertain. The normal fault is itself terminated by the Blood Canyon transverse 

fault. 

Normal jauU8 north oj Overland Canyon.-The normal faults 

north of Overland Canyon have exerted an even more striking 

influence upon the quartz monzonite intrusion than the northwesterly transverse fault. Four faults have been recognized, and all of them, in at least parts of their courses, 

form the contact between the intrusive and the sedimentary 

rocks. 

The most northwesterly of these faults forms the linear 

boundary of the isolated area of quartz monzonite east of 

benchmark 5855 at the head of Overland Canyon. Its course is 

east-northeast, and its dip is to the northwest. A quartzcarbonate vein follows the fault. A minimum estimate of the 

displacement is given by the upper contact of the Manning 

Canyon formation, which is cut off by the fault about 1,000 feet 

west of hill 6807. As the Manning Canyon is nowhereexposed 

on the hanging-wall side of the fault, the displacement must 

amount to at least 2,000 feet (sec. G-G'). The age of this fault 

with respect to the transverse fault is not known. 

The next fault to the southeast is perhaps open to question, 

because it is, throughout its exposure, bounded by quartz 

monzonite on the southeast. A quartz-carbonate vein is also 

found along this contact. There is little doubt that the monzonite was intruded along a fault, for, as shown in section G-G', 

there is a displacement of about 2,500 feet between the outcrops 

of the Manning Canyon formation at the Midas mine and those 

northwest of the monzonite. The greater part of the throw 

must have taken place along this fault, but a small part may be 

represented by the third fault of this group. This is exposed 

on the west side of the ridge about a mile north of the Midas 

mine; its throw is probably comparatively small, so far as can 

be determined by the members of the Oquirrh formation on 

its two sides. The age of the third fault relative to the northwesterly transverse fault is unknown; the second one is clearly 

older, as it cannot be recognized southwest of the transverse 

fault. 

The fourth fault is that at the Midas mine. The displacement 

here also is relatively small, amounting to about 350 feet. This 

fault must cut the northwesterly transverse fault, but the 

contact between the two has been destroyed by the intrusion. 

Just south of the Midas mine there is a fault of similar strike 

but with a low dip to the southeast. It is cut off by the Blood 

Canyon transverse fault, but beyond this its relations to the 

other faults are not known. 

Minor faults are abundant throughout this region, but the 

displacements rarely amount to more than 10 feet and on many 

are measured in inches. To the east the minor faulting is 

clearly shown by thin limestone beds. It was perhaps more 

abundant here because of the probable closer approach at this 

point to the underlying North Pass thrust. 

Ochre Mountain thrust.-The exposures of the Oquirrh formation that underlie hill 6519, on the northwest side of Clifton 

Flat, and the low hills north of the road to the Monocca mine, 

on the northeast side of Clifton Flat, belong to the western 

facies of the formation and must therefore lie above the Ochre 

Mountain thrust (secs. I-I' and L-L'). The beds exposed are 

rather thick-bedded cherty and chert-free limestones and 

dolomites, with only minor sandstones. Some of ~hem are 

identical with beds in the northwest quarter of the quadrangle, 

which are definitely a part of the western facies. The thrust 

plane is everywhere concealed by gravel within this block and 

may be located closely only on the southwest side of hill 6519, 

where the two facies of the Oquirrh formation are only a few 

hundred feet apart. 

Warping oj the North Pas8 and Ochre Mountain thrusts.-The 

two major thru3ts have both been considerably deformed in 

this block. This is shown not only by the outcrops of the 

North Pass thrust at altitudes considerably higher than in 

regions where the Oquirrh formation above the thrust is exposed, and by the younger reverse faults that cut through the 

thrust, but also by the close proximity of the two major thrusts 

in Clifton Flat. The warping is most intense adjacent to. the 

east-west transverse fault that bounds the block on the north. 

An anticlinal warping has brought the North Pass thrust to 

the surface in this region, and a syncline to the east has preserved 

a portion of the plate above the Ochre Mountain thrust. Similar 

warping is associated with the Garrison Monster transverse 

fault to the north (p. 83), where the two features are considered 

to be genetically related. 

The close proximity Of the two major thrusts in Clifton Flat 

permits a rough estimate of the thickness of the plate between 

them. The original eastward dip Qf the common limb between 

the anticline to the west and the syncline to the east has, 

however, been increased by two other factors. One of these is 

the eastward tilt imparted to the footwall block of the western 

border fault (p. 61); the other is that the northern continuation 

of the eastern border fault extends beneath this part of Clifton 

Flat, and although it cannot be recognized on the north side of 

the flat, it must be represented in the central part either by an 

actual fracture or by a pronounced downwarp to the east, as 

its throw on the south edge of the flat is still 2,000 feet. Neither 

of these factors can be accurately. determined, but rough estimates indicate that the North Pass thrust plate was probably 

about 2,000 to 2,500 feet thick at this point. 

TranslJersejauU on the south side oj Ochre Mountain.-A transverse fault is continuously exposed for more than a mile about 

half a mile south of hill 6886, south of Ochre Mountain, and is 

marked by a zone of silicified and crushed dolomite several 

hundred feet in width (sec. J-J'). In this portion of the fault 

the dip is steep, and the fault .separates the western facies of 

the Carboniferous to the north and the central facies of the 

Carboniferous to the south. These relations hold for the 

exposures of the fault in two gravel-surrounded outcrops to the 

east, but the breccia zone is considerably narrower. Still 

farther east the fault curves around the north end of hill 6519 

and the dip flattens notably. This pronounced change in the 

courEe of the fault corresponds with its intersection with the 

older Ochre Mountain thrust (sec. L-L'). The presence of the 

low-angle thrust fault at this point was probably the major 

factor in causing the change from steep to flat dip in the transverse fault, as the related Garrison Monster transverse fault to 

the north (p. 83) behaves in a similar manner where it cuts 

through an older thrust. 

It is highly improbable that the gently dipping portion of the 

fault represents a later thrust that has concealed the steeply 

dipping transverse fault, for there are no other exposures of 

such a fault in the higher areas to the northeast. 

East of hill 6519 the transverse fault is concealed by the 

gravel of Clifton Flat. It is thought to be represented east of 

the gravel by a wide crushed zone south of hill 6256, half a mile 

east of the road intersection at an altitude of 6,089 feet. This 

fault separates Ochre Mountain limestone on the north from 

the western facies of the Oquirrh formation on the southrelations similar to those shown by the transverse fault on hill 

6519, on the northwest side of the flat. The exposure of the 

fault extends only a short distance to the east, however, where 

it is terminated by a large normal fault that forms a part of the 

boundary of this structural block. 

The amount of movement along the transverse fault is not 

known. If an analogy may be drawn from the similar Garrison 

Monster fault, the pronounced warping south of the fau It implies 
72 GOLD HILL MINING DISTRICT, UTAH 

that the rocks on the north side moved relatively eastward. 

If that assumption is correct, there must have been a minimum 

movement of a mile in this direction. If the south side moved 

relatively eastward, however, the amount of movement must 

have been much greater. Both of these estimates are based on 

exposures of the Oquirrh formation north of the fault. 

Normal faults bordering the block east of Clifton Flat.-The 

normal fault that terminates the transverse fault described in 

the preceding paragraphs brings the central facies of the Oquirrh 

formation Oll. the east into contact with the western facies of 

the same formation. The throw must therefore be large, but 

it cannot be estimated in this region, for the altitude of the Ochre 

Mountain thrust sepa.rating the two facies cannot be determined 

on either side of the fault. The normal fault is considered 

related to the intrusion of the quartz monzonite, as shown by 

its relations in the block to the north (p. 76). 

The northeasterly fault three-quarters of a mile northwest 

of Montezuma Peak is poorly exposed throughout but is marked 

by a zone of shattering and erratic dips. The central facies 

of the Oquirrh formation forms both walls, and as no distinctive 

beds were recognized, its throw is unknown. The fault is perhaps related to the normal faults of similar strike on the southern 

slope of Montezuma Peak. 

Mutual relations of the structural features.-The Uiyabi Canyon block presents a sequence of structural events similar to 

that found in the Deep Creek Mountain block, to the south. 

Tilted normal faults in Uiyabi Canyon are probably older than 

the major anticline on the south side of Clifton Flat. The anticline itself and some of the normal faults on the south side of 

Montezuma Peak in turn antedate the North Pass thrust and 

related features that were formed in the third structural cycle. 

Normal faults that cut these features are in turn cut off by the 

great transverse faults, or by their associated faults which characterize the fourth cycle. The transverse fault on the south 

side of Ochre Mountain is itself cut by a normal fault related to 

the intrusion. Finally, the late normal faults are found on the 

south side of Clifton Flat and along the western border of the 

block. . OCHRE MOUNTAIN BLOCK 

The Ochre Mountain block includes not only Ochre Mountain but also the low-lying hills to the north. Its northern 

boundary is marked by the wedge-shaped tongue of quartz 

monzonite that extends westward from the town of Gold Hill 

along the south side of Dutch Mountain. To the west the block 

is limited for several miles by the western border fault, but this 

fault appears to die out at about the northwest point of Ochre 

Mountain, and from this point to the western tip of the quartz 

monzonite wedge the boundary of the block follows gravel-filled 

valleys that have no structural significance. The main body 

of quartz monzonite lies east of the block. It includes several 

roof pendants of sedimentary rocks, whose structure is considered in this section. 

The Ochre Mountain thrust is the dominant structural feature 

in the block (sec. K-K', M-M'). A nearly continuous exposure 

of this fault extends in a north-northwesterly direction from 

the quartz monzonite stock to the northern boundary of the 

block. The thrust is also exposed in a "window" west of the 

thrust, and in several of the roof pendants. Several transverse 

faults with low north dips are exposed on Ochre Mountain that 

are thought to be contemporaneous with the major thrust (sec. 

J-J'). There are in addition several others, chiefly normal 

faults, whose relations both to one another and to the thrusts 

provide the moo:t complete chronologic sequence found in the 

whole quadrangle (sec. K-K'). 

Over much of the block the rocks are poorly exposed, owing to 

the fact that the present surface closely parallels the old post.. 

mature surface (p. 61) and faults are difficult to trace. The 

absence of distinctive beds in the Ochre Mountain limestone, 

which underlies much of the area, adds to the difficulty and prevents accurate measurement of fault throws in many places. 

On the western face of Ochre Mountain rock exposures are 

unusually good, and several distinctive beds are present. As a 

result, many faults were recognized, and their abundance in 

this region probably provides a measure of the amount of faulting in the remainder of the block. 

Main outcrop of the Ochre Mountain thrust.-The most southeasterly outcrop of the Ochre Mountain thrust is just west of 

the Lincoln Highway about a quarter of a mile north of benchmark 5723. At this point, north of and below the thrust, are 

sandstones and black shales belonging to the central facies of 

the Manning Canyon formation. These beds are badly crumpled and show marked variations in strike and dip. To the 

south and above the thrust are poorly exposed black shales with 

a few interbedded fossiliferous limestones that belong to the 

western facies of the same formation. They are overlain by 

cherty dolomites and limestones of the Oquirrh formation. The 

thrust is poorly exposed here, and were it not for the difference 

in lithology between the two facies of the Oquirrh formation 

overlying the two areas of the Manning Canyon, it might easily 

pass unrecognized. To the southeast the termination of the 

thrust by the quartz monzonite stock is concealed by gravel. 

To the west and north the thrust is also concealed by gravel 

for some distance. The beds at thc base of the ridge above the 

northern Ochre Spring are the Ochre Mountain limestone and 

the western facies of both the Manning Canyon and Oquirrh 

formations. They show rather variable strikes and dips, and 

this variation is illustrated by the irrcgularity of the outcrops 

of the three formations. Hill 5919, between the two springs, 

is covered largely by quartzite float, but the tunnel at the northern spring indicates that the quartzite is present as thin beds in 

less resistant black shale. East of these beds and surrounded 

by gravel are several low hills composed of the central facies of 

the Manning Canyon formation. The thrust must be concealed 

by the gravel between the outcrops of the two facies. 

About a. quarter of a mile west of the point at an altitude of 

5,658 feet shown on the map the concealed thrust is cut by an 

eastward-dipping normal fault. West of the normal fault, 

whose post-thrust throw is about 150 feet, the thrust is shown 

by eastward-dipping thick-bedded Ochre Mountain limestone 

resting upon the central facies of the Manning Canyon formation. The stratigraphic displacement along the normal fault 

in the beds above the thrust amounts to several thousand feet. 

The normal fault has clearly been active at least twice, therefore, the bulk of the movement being earlier than the thrust. 

The normal fault has also caused the exposure of the thrust 

southwest of hill 5919 between the two Ochre Springs. The relations here are similar to those west of the fault to the north. 

Northwest of this normal fault there are two lines of outcrop 

of the thrust, as a result of an east-west normal fault whose 

throw is about 50 feet. To the north another normal fault, of 

northwesterly strike, displaces the thrust 100 feet. A small 

"klippe" or thrust outlier occurs on peak 5959, northeast of 

this region, Ochre Mountain limestone above the thrust resting 

upon beds low in the Oquirrh formation. The salient of the 

thrust due west of the "klippe" conceals the Manning Canyon 

and Oquirrh contact in the overridden rocks for nearly half. a 

mile. Locally the Ochre Mountain limestone above the thrust 

shows zones of disturbed dips parallel to the thrust that appear 

to represent minor sympathetic thrusts. These are commonly 

reflected in the topography by pronounced benches. 

Just north of the intersection of the thrust with the trail 

from Gold Hill to the Erickson ranch, the western facies of the 

Oquirrh formation replaces the Ochre Mountain limestone as 

the formation above the thrust. This is the result of an eastnortheast fault earlier than the thrusting. The east-northeast 

fault is exposed for only a short distance along the divide 
GEOLOGIC STRUCTURE 73 

between the Gold Hill and Deep Creek drainage basins, but 

its persistence for nearly 3 miles westward is proved by the 

continued presence of the Oquirrh formation to the north of 

the trail and of the Ochre Mountain limestone to the south. 

The age relations of this fault seem to ally it with the northnorthwest transverse faults, in spite of its divergent strike, 

which may be the result either of a low dip or of warping accompanying the thrusting. 

North of its intersection with the transverse fault the overthrust can be traced continuously for more than half a mile. 

Its outcrop is sinuous, owing chiefly to the effect of the topography, although variations in dip play some part. The western 

facies of the Oquirrh formation continues to overlie the thrust 

and beneath it are found Ochre Mountain limestone and the 

central facies of both the Manning Canyon and the Oquirrh. 

The appearance of the Ochre Mountain limestone immediately 

below the thrust coincides with an increase in complexity in 

the structure of the overridden rocks. Two minor thrusts in 

the rocks below the thrust were recognized in this region in 

addition to minor folds (sec. N-N'). The more southerly of 

the minor thrusts is exposed just north of the road to the Erickson ranch and east of the outcrop of the main thrust. It has 

resulted in the Ochre Mountain limestone overriding the Manning Canyon formation. The strike of the minor thrust is 

nearly at right angles to the strike of the bedding.. Because of 

this it involves, in addition to the Ochre Mountain limestone, 

both the Manning Canyon and Oquirrh formations. The relatively small displacement suffered by the Manning Canyon and 

Oquirrh contact on the northeastern extension of the fault 

indicates that the fault dies out within a rather short distance 

in this direction. The changes in strike of this contact in the 

overridden beds are considered to have been developed as a 

result of the thrust. The behavior of the minor thrust described 

in the next paragraph indicates that the dip of this fault probably steepens notably along its southwestern extension and that, 

coincident with the change in dip, the strike swings to nearly 

east-west. 

These two features are clearly shown by the second of the 

minor thrusts, which is found just beneath the Ochre Mountain 

thrust east of peak 6125. Here, in the east-west draw north of 

hill 5925 both the minor thrust and the major thrust· are well 

exposed. The minor thrust strikes nearly due east and dips 

60° N. Ochre Mountain limestone is found above the fault, 

and the Manning Canyon formation below. Toward the east 

the strike of the thrust swings to the north and the dip flattens 

notably, as is shown by the trace of its outcrop. Only a small 

width of the thrust plate of Ochre Mountain limestone is 

exposed, owing to overlapping by the main thrust. 

The complexity in structure shown by the overridden rocks 

in this region contrasts with the simple structure to the southeast, where the contact between the Manning Canyon and 

Oquirrh formations shows that there has been little deformation 

of the rocks beneath the thrust. It seems probable that the 

change in structure is due to the presence of the resistant 

Ochre Mountain limestone immediately below the thrust in 

the northern area, in that the competent limestone is much 

more readily fractured and that a break in the limestone would 

involve breaking in the immediately adjacent nonresistant beds. 

The outcrop of the Ochre Mountain thrust is terminated 

less than a quarter of a mile north of the second of the minor 

thrusts by a northwesterly normal fault. This normal fault 

forms the contact between beds above the thrust to the west 

and beds below the thrust to the east, northward from the intersection to the northern boundary of the block. The throw 

along the normal fault amounts to about 300 feet (p. 77). 

"Window" west of the main outcrop of the Ochre Mountain 

thrullt.-Another isolated and poor outcrop of the thrust is in 

a. "window" in the open valley about three-quarters of a mile 

lIIl3ll-36-6 

west of the Ochre Springs (sec. M-M'). The presence of the 

thrust here is shown by outcrops, in the floor of the valley and 

near its edges, of beds of the Ochre Mountain limestone and the 

Manning Canyon and Oquirrh formations, in striking unconformity with the eastward-dipping Ochre Mountain limestones 

on each side. This relation is most clearly shown in the southeast corner of the valley, where there are small outcrops of the 

Manning Canyon and Oquirrh formations. The beds of the 

Ochre Mountain limestone immediately above the fault have 

irregular strikes and dips, in striking contrast to the uniformity 

of their attitude higher on the ridge. The thrust has caused 

an erratic distribution of the three formations that are here 

beneath it, but the lack of an adequate number of outcrops 

prevents the determination of the character of this deformation. In the left-hand portion of section M-M' it is extremely generalized. 

Ochre Mountain thrust east of the Lincoln Highwa.y.-Although 

the main outcrop of the Ochre Mountain thrast is terminated 

.on the southeast by the quartz monzonite, there is ample 

evidence that the thrust plate originally extended much farther 

eastward, over the region now underlain by the intrusive rock. 

This is shown by the ocCUrrence of the western facies of the 

Carboniferous formations in roof pendants and locally by small 

exposures of the thrust itself. In this region, however, the 

thrust plane has been affected by faulting related to the 

intrusive. 

The exposures of the Oquirrh formation· on the east side of 

the Lincoln Highway and south of the point where the thrust 

crosses the road belong to the western facies of the formation 

and are the continuation of beds west of the road that occur 

above the thrust. These beds are west of a north-south tongue 

of the quartz monzonite, which has apparently followed a preexistent north-south fault, as to the east Ochre Mountain limestone is exposed. The limestone is now separated by rather 

narrow belts of quartz monzonite on the north, 'east, and south 

from othermasses of Ochre Mountain limestone and was proba· 

bly continuous with them before the intrusion. The Hmestone 

masses are those in the vicinity of the Lucy L mine, the large 

roof pendant north-northeast of Clifton, which includes also 

beds of the western facies of the Oquirrh formation, and the 

block of limestone upon which Clifton itself is built. 

All these exposures are considered to be above the Ochre 

Mountain thrust, for at several places the limestone is in contact with either the Manning Canyon or the Oquirrh formation, 

in relations that can be explained only by thrusting. This is 

definitely proved at the Lucy L mine, where mine workings 

expose the thrust and also show that beds belonging to the 

central facies of the Oquirrh formation extend beneath a hill 

capped with Ochre Mountain limestone. (See p. 141 and 

fig. 26.) The localities at which the thrust was rellognized 

in this region are shown on plate 3. 

The distribution of the small exposures of the thrust show 

that it has suffered deformation in this region as compared to 

its relatively undisturbed condition to the west and north. 

Two normal faults seem to have been the chief factors in the 

deformation. One of these is the northern continuation of a 

fault that displaced the thrust in the Uiyabi Canyon block 

(p. 72) and has dropped the beds to the west at least 1,000 feet. 

The second fault terminates on the west the exposures of the 

thrust and the rocks above it just west of the Lucy L mine. 

Its throw cannot be accurately measured but must be of the 

same magnitude as that of the parallel fault to the west, 

although in the opposite direction. 

The restriction of these large post-thrust disturbances to the 

.vicinity 	of the quartz monzonite suggests that the faulting is 

genetically connected with the intrusion, and this view seems 

to be somewhat confirmed by features of the ore deposits 

observed near the faults (pp. 88-89). 
74 GOLD HILL MINING 

Magnitude <Jf the Ochre Mountain thrust.-The amount of 

movement along the thrust cannot be accurately determined. 

The force causing the thrust must have come froID the west, 

and a minimum estimate may therefore be obtained from the 

distance between the easternmost and westernmost outcrops 

of the thrust, or of rocks known to overlie the thrust. This 

distance amounts to more than 5 miles. It must, however, be 

far short of the true figure, for the lithologic distinction between 

the westernmost outcrop of the central facies of the Oquirrh 

formation beneath the thrust and the easternmost outcrop of 

the western facies is everywhere evident. A figure approximating 20 miles would seem to be nef!.rer the true amount but has, 

of course, no basis in field observations. 

Northward-dipping transver8e faults on Ochre Mountain.­

Three faults with rather low north dips and east strikes occur 

on Ochre Mountain in the rocks above the Ochre Mountain 

thrust. They are in general poorly exposed and are therefore 

difficult to trace. All these faults are probably contemporaneous with the main thrust, for their relations to normal faults 

appear to be the same as those shown by the thrust. The 

movement along two of the faults appears to have been dominantly horizontal, and, as the other is closely related to them, 

they are all considered to be rather flat portions of transverse 

faults. 

The southern of the three faults was recognized at 'several 

places south and east of the summit of Ochre Mountain but waS 

not traced definitely between these points. The longest of 

these recognized outcrops was found at the head of Gold Hill 

Wash, where the fault crosses the thlCOln Highway 500 or 600 

feet southwest of benchmark 5972. In this region the Ochre 

Mountain limestone is north of the fault and the western facies 

of the Manning Canyon and Oquirrh formations to the south. 

The fault is cut off on the east by the same normal fault that 

cuts the Ochre Mountain fault near Ochre Springs (p. 72). 

East of the normal fault the continuation of the transverse 

fault is uncertain because of faulting related to the quartz 

monzonite intrusion, but segments of faults that may represent 

portions of it are shown on plate 3. West of the highway the 

fault may be traced for nearly a mile because of discordant 

stratigraphic relations. Two small outcrops are readily found 

farther west by reason of the relations between the Ochre Mountain limestone and the Woodman fotIilation. The most westerly exposure occurs along the nol'theast side of the pronounced 

bench at an altitude of about 6,800 fel:lt that lies between summits 7233 and 6886, on the south !!ide of Ochre Mountain. The 

Herat shale member of the Ochrt;) Mountain limestone caps the 

bench and lies below (south of) the fault. The same member is 

also exposed above the fault just south of the summit of Ochre 

Mountain. The fault was not traced west of the bench, but 

it may continue along the west face of the mountain and join 

the second of the transverse fauits, as no offsetting that can be 

attributed to it alone was recognilled. The fault has its highest 

altitude and lowest dip at the 6,800 foot bench, and it decreases 

in altitude markedly to the east, where the dip appears to be 

consiHerably steeper. If it joins the other transverse fault at 

the west, it must decrease its altitude in that direction also. 

This variation in altitude is considered to be partly the result 

of original variations in dip and partly the result of later deformation, the eastward tilt caused by the western border fault 

(p. 61) being one of the most influential factors. 

The movement along the fault is estimated at about 2,500 

to 3,000 feet, the beds north of and above the fault moving eastward; This measurement is based upon the correlation of 

structural features on the two sides of the fault. The large 

normal faUlt that forms the western boundary of the exposures 

of the Oquirrh formation along the Lincoln Highway east of" 

Ochre Springs is correlated with a fault south of the fault with 

rather similar relations 1,000 feet west of benchmark 6163 at 

DISTRICT, UTAH 

the north end of Clifton Flat; the faults bounding the graben 

of Oquirrh formation composing hiP 6439, north of the fault, 

are correlated ",1th the faults that compose the graben of Ochre 

Mountain limestone north of hill 6519, south of the fault; and 

the fault 2,000 feet west of hiJl7150, which limits the Woodman 

formation on the west, is correl"ted with the similar fault west 

of the bench at 6,800 feet. The stratigraphic throw shown by 

the Herat shale member of the Ochre Mountain limestone is 

also satisfied by a displacement of this magnitude. 

A second fault with low north dip crops out 1,500 feet south 

of the highest point on Ochre Mountaih. It terminates on the 

west a band of Herat shale, and farther east in the amphitheaterlike valley below the summit it is recognized by considerable 

crumpling in the massive beds of the Ochre Mountain limestone. 

On the western flank of the mountain it may be recognized at 

several places as a result of the relatively recent extensive erosion 

(pI. 7, A) and also by its termination of the belt of Woodman 

formation and the fault that bounds that formation. The 

amount of movement along this fault could not be determined, 

as the beds above it are all of the Ochre Mountain limestone. 

The altitude of the outcrops of the fault ranges from about 

6,650 to 7,250 feet. The highest point is on the bench north of 

pet).k 7233. 

The last of the group of low-angle faults whose outcrops have 

a dominantly east-west trend is found on the north slope of 

Ochre Mountain. The chief outcrop of this fault is north of 

hill 6439, on the east side of the mountain. Here the fault 

strikes west-northwest and dips at a moderately low angle to the 

north. The footwall side is marked by extensive silicification. 

A down-faulted block of Pennsylvanian rocks is cut by the fault, 

and these beds south of the fault are shifted about 1,700 feet 

relatively east. A probable westwe.rd continuation of the fault 

was found about a mile to the west, just north of peak 7000. 

Other outcrops thought to represent this fault occur a mile still 

farther west, where, however, there are two faults with the same 

approximate strike as in the other outcrops but with a nearly 

vertical dip. Although these three outcrops were not traced 

into one another, it is thought that they are parts of the same 

fault, whose dip flattens eastward and upward. 

Southward-dipping tran8verlle faults on Ochre Mountain.-A 

fault striking west-northwest and dipping at a moderate angle 

to the south is exposed on the south side of Ochre Mountain 

s.outh of the bench at an altitude of 6,800 feet. To the northwest the fault abuts against a younger normal fault, and to the 

southeast it is covered by gravel, although it must be cut by 

the east-west transverse fault that bounds the block on the 

south. Several normal faults exposed north of the fault are 

clearly terminated by the transverse fault. 

An apparent measure of the throw along the fault is given 

by the positions of the Herat shale member of the Ochre Mountain limestone and the Woodman and Ochre Mountain contact 

on both sides of the fault. These show that the beds south of 

the fault have dropped vertically about 700 feet. A simple 

vertical movement, however, is impossible, because of the lack 

of correspondence of structure on the two sides of the fault, 

and particularly because of the absence, to the south, of any 

fault that might correspond with the normal fault east of the 

6,800-foot bench that forms the western boundary of the W oodman formation. This, together with the erratic northeasterly 

strikes found at many places adjacent to the fault, suggest that 

it is a transverse fault. Its termination to the westby a normal 

fault that is in turn cut off by the northward-dipping transverse 

faults implies that it belongs to a different structural cycle from 

the other transverse faults on Ochre Mountain.:' . 

A second parallel fault crops out 1,000 feet east of hill 6634, 

on the southwest spur of Ochre Mountain. The vertical component of its throw amounts to 250 feet, as shown by the Woodman and Ochre Mountain contact on both sides of the f~ult, 
r 


GEOLOGIC 

but a purely vertical movement is improbable because the 

displacements of two older normal faults require the movement 

along the fault to have been dominantly horizontal, the north 

side moving relatively eastward about 1,000 feet. 

Minor thrusts and fold on south Bide of Ochre Mountain.-Two 

minor thrusts and a small anticline are exposed on the southwestern spur of Ochre Mountain that are thought to have been 

formed during the first structural cycle. The more westerly 

thrust crops out just east of the point at an altitude of 5,613 feet 

on the road along the west side of Ochre Mountain and is 

terminated eastward by a younger normal fault. The displacement of the thrust is unknown, as it is within the Ochre 

Mountain limestone. 

About half a mile to the southeast, another minor thrust is 

exposed. This fault separates beds high in the Guilmette 

formation, as shown by the lithology and by the presence of the 

large clam, Pycinodesma sp., from beds high in the Woodman 

formation. The stratigraphic throw thus amounts to nearly 

the thickness of the Woodman formation (about 1,500 feet), 

but the total movement along the fault is larger than this, as 

the low east dip of the fault nearly coincides with the dip of the 

bedding. The thrust is terminated at the northwest by a 

normal fault and at the southeast by the transverse fault that 

forms the southern boundary of the block. 

A minor anticlinal fold is exposed on the west side of hill 

6886, south of the summit of Ochre Mountain. It is terminated 

on the north by a transverse fault of the second cycle. 

Normal faults on Ochre Mountain.-By means of their relations to the thrusts and transvene faults, the normal faults on 

Ochre Mountain are seen to belong to three different chronologic groups, corresponding to the first three structural cycles. 

Those of the first cycle are probably the most abundant. 

The two most westerly normal faults belong to the oldest 

group, as they are offset by a transverse fault of the second 

cycle. Both dip about 45° W. The throw along the western 

fault is unknown, but the eastern one drops the beds on its 

hanging-wall side about 2,000 feet. 

About 1;500 feet east of hill 6634, on the southwest spur of 

the mountain, another westward-dipping normal fault crops out. 

This belongs to the second structllral cycle, however, as it cuts 

a transverse fault of the second oyole and is cut o.ff by one of the 

third cycle. The throw along this fault amounts to about 2,000 

feet also, as is shown by the position of the upper contact of • 

the Woodman formation on 6Mh side. In the gulch that heads 

between peaks 7102 and 7182, on the ridge line of Ochre Mountain, the fault is cut by one of the northward-dipping transverse 

faults. Beneath the transverse fault, which has a very low dip 

at this point, the strike of the normal fault swings to east of 

north, its dip flattens and the beds on each side are crumpled. 

The compressive forces that ca.used the flat fault evidently were 

also partly relieved by some movement along the older fault. 

North of the intersection a north-south fault is exposed that 

appears to be a continuation of the normal fault to the south, 

but the known displacement along the transverse fault (about 

2,000 feet) makes a correlation impossible. At the north end of 

the mountain, along the continuation of this line of faulting, 

still another westward-dipping normal fault is found. The 

throw along the fault cannot be exactly determined but must 

be considerable, because the beds on the footwall side are near 

the base of the Ochre Mountain limestone, and those on the 

hanging-wall side are rather high in the formation. This fault 

is terminated on the south by the northern of two northwestward-striking transverse faults. Adjacent to the transverse 

fault the strike of the normal fault swings to the southwest, and 

its dip is notably flatter-phenomena similar to those exhibited 

by the normal fault to the south at its intersection with a 

younger transverse fault. As the displacements along the 

branching transverse fault to the north and the flat transverse 

STRUCTURE 75 

fault to the south are roughly compensatory, it is possible that 

the most northerly and southerly normal faults are segments of 

the same fault. 

Two north-south normal faults east of the 6,800-foot bench 

on the south side of the mountain are similar in the character 

of their displacement as well as in strike. Both are older than 

the transverse fault of the second cycle that is exposed in this 

region. The western of the two normal faults has a throw of 

nearly 2,000 feet; the eastern, about 500 feet. North of the 

third-cycle transverse fault that cuts these faults on the north 

only one north-south fault of large throw was recognized. This 

crops out about 2,000 feet east of the southward-trending ridge 

whose altitude is 7,150 feet. It is the continuation of the more 

westerly of the two normal faults south of the transverse fault, 

as it corresponds to that fault in stratigraphic relations. The 

more easterly of the two normal faults to the south is perhaps 

represented north of the transverse fault by a poorly exposed 

fault in the valley east of summit 7130. 

Three more normal faults are present north and northwest of 

hill 6519, on the southeast spur of Ochre Mountain. The 

westernmost one has a small downthrow to the east, as shown by 

the presence in the hanging wall of beas low in the Ochre 

Mountain limestone. The two more easterly faults are exposed on both sides of hill 6475, which is 2,000 feet north of hill 

6519. These two faults form the boundaries of a graben of beds 

high in the Ochre Mountain limestone, the Woodman formation 

being exposed east of the graben and basal beds of the Ochre 

Mountain limestone west of it. 

These two normal faults are cut by the most southerly of 

the northward-dipping transverse faults and north of the intersection are shifted about 2,500 fe-et to the east. The depressed 

block between the faults (hill 6439) in the region to the north 

is made up of beds low in the Oquirrh formation, as shown by a 

small exposure of the Manning Canyon formation to the north. 

The graben is also cut by a second transverse fault farther 

north and shifted l,750 feet westward. The beds in this segment of the graben are also basal members of the Oquirrh formation and the upper portion of the Manning Canyon formation. 

The bounding faults of the graben converge northward in this 

region and are very nearly united where they are cut off by the 

Ochre Mountain thrust along the south side of the "window" 

described on page 73. They were not recognized on the north 

side of the "window." 

The faults that bound the graben are clearly older than 

the northward-dipping transverse faults and Ochre Mountain 

thrust of the third cycle. They appear to be unaffected, however, by a minor transverse fault which is exposed 2,000 feet 

northwest of bench mark 6163 at the north end of Clifton Flat, 

and which was probably formed in the first stage of the second 

cycle. The two normal faults, therefore probably represent the 

normal faulting of the second cycle. 

Another normal fault of the second cycle with a northerly 

strike is exposed 1,000 feet west of bench mark 6163. This fault 

dips eastward and has a throw about equal to the thickness of 

the Ochre Mountain limestone, for beds of the Manning Canyon 

formation are found on the hanging wall and beds near the base 

of the Ochre Mountain limestone make up the footwall. The 

fault is not affected by the second-cycle transverse fault shown 

on the ridge to the west but is cut by the southern of the thirdcycle transverse faults. The faulted segment is 3,000 feet to 

the east on the north side of the transverse fault, where it forms 

the western boundary of the mass of Oquirrh formation exposed 

along the Lincoln Highway. There has been renewed movement amounting to about 150 feet along this segment, as shown 

by the offsetting of the Ochre Mountain thrust (p. 72). 

Structural features east of the Lincoln Highway and south of the 

U.S. mine.-The most striking structural feature in the region 

east of the !,incoln Highway is a horst affecting the Ochre 

_ ....__..._-.. _--------------------------­
16 GOLD HILL MINING 

Mountain thrust, which is probably genetically related to the 

intrusion of the quartz monzonite stock; The fault that bounds 

the horst on the west extends northward from hill 6455, about 

1Ya miles northwest of the town of Clifton and is a northern continuation of the fault described on page 72. In this vicinity 

the fault appears to have at least three branches. A small mass 

of quartz monzonite has followed the fauIt zone for more than 

a mile, north of the branched portion, but a northern continuation appears to be represented by the fault 1,000 feet east of 

the highway in the region east of Ochre Springs. The beds on 

the footwall side of the block have been elevated relative to 

those on the hanging-wall side. Both to the north and to the 

south the beds of the central facies of the Oquirrh formation 

are exposed in the footwall and have been raised to altitudes 

several hundred feet higher than the Ochre Mountain thrust 

plane, which they normally underlie. North of hill 6455 beds 

above the thrust are found on the footwall side of the fault, but 

even here the thrust is considerably higher than west of the 

normal fault. 

This fault zone must also have been the site of movement 

before the Ochre Mountain thrust, for west of it the western 

facies of the Oquirrh'formation is above the thrust, but to the 

east the Ochre Mountain limestone has this position. The 

pre-thrust throw must have been large but cannot be closely 

estimated as the horizon in the Ochre Mountain limestone east 

of the fault is unknown. The post-thrust movement may have 

been somewhat smaller but certainly has amounted to at least 

several hundred feet and to the south may havc been more than 

1,000 feet. The relations north of hill 6455 suggest that the 

post-thrust throw may have been variable along the strike. 

Several more or less east-west faults in the vicinity of hill 

6455 are cut by the normal fault zone, but their short extent 

and the considerable metamorphism of the adjacent beds make 

their true nature uncertain. They perhaps represent faulted 

segments of either the Ochre Mountain thrust or the northward-dipping transverse faults of the same age. 

The fault that bounds the horst on the east is exposed at two 

places. Near the Lucy L mine the central facies of the Oquirrh 

formation is brought into contact with Ochre Mountain limestone that lies above the Ochre Mountain thrust. The second 

exposure of the fault is west of the town of Clifton. Here the 

fault dips about 30° E. and has similar relations, except that 

the Ochre Mountain thrust is not exposed below the Ochre 

Mountain limestone in the hanging wall (sec. I-I'). The limestone, however, appears to have been originally continuous 

with the beds in the roof pendant northeast of the town, which 

definitely overlie the thrust. 

Two large faults cut the roof pendant northeast of Clifton. 

One of them strikes east of north and separates fossiliferous beds 

of the western facies of the Oquirrh formation on the east from 

Ochre Mountain limestone on the west. The fault is similar 

in relations to the normal faults of the second cycle on Ochre 

Mountain and is probably of that age. 

Both the normal fault and the outcrop of the Oquirrh formation are terminated on the south by a fault striking eastnortheast and dipping, in its western portion, 60° N. This 

fault is difficult to trace toward the west in the Ochre Mountain 

limestone but seems to be marked by a zone of crumpling and 

minor overturned folds along the projected strike. These 

features suggest that the fauIt is one of the group of northwarddipping transverse faults that are cxposed on Ochre Mountain. 

The Ochre Mountain limestone in the roof pendant has 

undergone minor folding. Section K-K' shows a shallow 

syncline that appears to be limited to the northwestern part of 

the pendant, but an asymmetric anticline to the east is more 

continuous. 

The exposures of thc central facies of the Carboniferous formation immediately east of the Lincoln Highway and west of 

the westerly normal fault related to the intrusion lie immediDISTRICT, UTAH 

ately beneath the Ochre Mountain thrust. Although metamorphism and local gravel capping mask their structure considerably, it is clear that they are irregularly warped. The 

outcrop of Ochre Mountain limestone near the north end of the 

exposure of these rocks requires a local doming in the overridden rocks at that point. 

Minor faults are probably rather abundant in the beds near 

the quartz monzonite but are readily recognized only where 

prospect pits or mine workings provide suitable exposures. 

Thus several faults were recognized at the Lucy L mine (p. 141 

and pI. 13) and at the Wilson Consolidated mine (p. 139 and 

fig. 25). 

Faults near the U.S. mine.-Three faults are exposed in the 

vicinity of the U.S. mine. One of these, just south of the mine 

office, offsets the Ochre M.ountain and Manning Canyon contact 

about 200 feet and is clearly earlier than the intrusion. The 

second fault, which strikes east-northeast and dips .600 S., ·crops 

out 250 feet south of the portal of the main tunnel of the mine. 

It has beds low in the Oquirrh formation on its hanging wall 

and cuts across the Ochre Mountain and Manning Canyon 

contact in the footwall, indicating a throw of about 1,000 feet. 

The fault is rather poorly exposed at the surfaee and is seen 

underground only at the face of the most southerly working on 

the tunnel level. Beyond the fact that the fault is earlier than 

the intrusion its relative age is unknown. It is shown on plate 

3 as a normal fault of the first cycle but this is purely conjectural. 

As shown in section M-M' the fault appears to be nearly horizontal, but this is the result of the essential parallelism between 

the line of section and the strike of the fault. 

The third fault is northwest of the mine workings and forms 

the contact between the intrusive and sedbnentary rocks. It 

cannot be recognized at the surface as the contact is covered by 

talus from the sediments above. Underground, however, the 

contact is exposed in the workings on the 234-foot level northeast of the shaft, where it is seen to be a fault striking about 

northwest and dipping 35° SW. On section M-M' the fault 

is shown as a normal fault, but the low dip perhaps makes this 

interpretation questionable. If the fault is considered to be 

normal, the throw may be about 200 to 300 feet; but if it is a 

reverse fault, the throw would necessarily be much greater, 

As no sign of the fault was observed along its projected course 

on the west side of Gold Hill Wash, it must die out in that 

direction; and therefore the smaller throw required by th~ 

normal fault makes that interpretation preferable. Several 

minor faults or shear planes were observed underground in the 

U.S. mine and are described on pages 158-160. 

TranslJersejault north oj Ochre Springs.-The structure in the 

fiat west of the Lincoln Highway and northeast of Ochre Springs 

is obscure, as the outcrops of the Manning Canyon formation 

are low mounds covered by angHlar blocks of dark quartzite. 

The bedding is presumably nearly horizontal, as the exposures 

are found over a wide area. On the north side of the fiat the 

low hills are composed of eastward-dipping beds of the Oquirrh 

formation. The discordance between the observed dip here 

and the inferred dip of the Manning Canyon outcrops in the 

flat suggests an east-west fault between them, and this suggestion is confirmed by the continuous exposures to the west, 

where a transverse fault forms the contact between the two 

formations. This fault is clearly older than the Ochre Mountain 

thrust, which is not affected by it. 

Northwesterly normal jaults west of the Lincoln Highway and 

east of the main outcrop of the Ochre Mountain thrusl.-There are 

probably several northwestward-striking normal faults in the 

region west of the Lincoln Highway that are not shown on 

plate 2, but the rather poor exposures and the lack of distinctive 

beds in the central facies of the Oquirrh formation prevent 

accurate mapping. 

The most westerly of the recognized faults of this group may 

be traced with minor interrnptions from the north side of the 

'­
I 

r • 

r 

GEOLOGIC STRUCTURE 77 

Hat north of Ochre Springs to the northern boundary of the 

block. The fault dips to the west, one exposure of the fault 

plane showing a dip of 70°. Over much of its outcrop the 

Manning Canyon formation is exposed in the footwall and beds 

low in the Oquirrh formation in the hanging wall. Farther north 

the relations are not so simple, as a result of intersections with 

other faults, and for the most northerly half mile of outcrop in 

this region, the fault forms the boundary between the overriding and overridden rocks of the Ochre Mountain thrust. 

This portion of the fault is cut by younger northeasterly faults. 

The throw along the fault is about 300 feet. 

Two parallel faults to the northeast have both been traced 

for more than a mile by means of zones of disturbed strikes and 

dips. Both faults dip to the northeast, however. Their throw 

is between 200 and 300 feet, as nearly as can be estimated. 

Neither of these faults can be traced confidently much north 

of the road from Gold Hill to the Erickson ranch. 

Another fault with northwesterly strike may be traced from 

Gold Hill Wash just south of the town of Gold Hill to the northern bdundary of the block. It dips to the southwest and appears 

to have its maximum throw of about 1,000 feet in the vicinity 

of the Cane Springs mine. The throw probably decreases to 

the north. 

Northeasterly fauUs west and northwest of Gold lIill.-Several 

northeastward-striking faults may be recognized in the region 

west of Gold Hill. Most of them are the youngest structural 

features in that region, as they cut the northwesterly normal 

faults, some of which in turn are younger than the Ochre 

Mountain thrust. The amount of displacement along these 

faults is small, but many of them are reverse faults. 

Locally the northeasterly faults appear to die out to the 

southwest. This feature is best shown about three-quarters of 

a mile west of Gold Hill. Here a northeasterly fault, which to 

the northeast clearly offsets a northwesterly fault, has merely 

warped a second northwesterly fault, and still farther to the 

southwest its influence cannot be recognized at all. 

Although the larger number of these faults are younger than 

the other structural features, some must represent an older 

generation' of faulting. This is shown about three-quarters of 

a mile south of bench mark 5885 on the Ferber Road, where one 

of these northeasterly faults is cut off sharply by a northwesterly 

fault. A parallel northeasterly fault a short distance to the 

north offsets the northwesterly fault, however. The northeasterly faults at this locality also show that there are two 

generations of northwesterly faults, as both of the northeasterly 

faults are younger than a northwesterly fault whose dip is 

45° SW. and whose throw is about 250 feet. 

Transverse fault at the northern border of the block.-Exposures 

immediately north and west of benchmark 5885 on the Ferber 

Road show that there must be a nearly east-west transverse 

fault in this region. The fault is now concealed through much 

of its course, however, by the tongue of quartz monzonite, or, 

locally, by gravel. In view of the known relation between the 

intrusion and preexistent faults in other parts of the quadrangle, 

it seems probable that this transverse fault may have controlled 

the intrusion of the tongue along the northern border of the 

block. 

The areal 8.8I'lociation of a nearly east-west transverse fault 

and northeasterly faults, both of which are relatively young, 

is similar to conditions near the Garrison Monster mine, 

Structural features in the vicinity of the Western Utah mine.­

The most striking fault near the Western Utah mine is that 

marked by a linear outcrop of jasperoid replacement of fault 

breccia that passes through Gold Hill. Over most of its length 

the fault forms the eontact between the Ochre Mountain limestone and the Manning Canyon formation. Its dip is about 

60° K This is almost the same as the dip of the beds on each 

side of the fault in the vicinity of the mine, and it is only when 

beds of the Ochre Mountain limestone are traced to the north 

and found to change their strike to nearly east-west that the 

considerable throw of the fault is realized. The throw along 

the fault is unknown, but a minimum estimate, based on the 

thickness of Ochre Mountain beds terminated by the fault, is 

about 1,000 feet. 

On the eastern slope of the hill the relations of the Ochre' 

Mountain limestone and the Manning Canyon formation indicate the presence of a synclinal fold. Owing probably in large 

part to the fault described above, the dips on the western limb 

are much steeper than those on the eastern (sec. M-M'). The 

fold is cut by a fault striking N. 30° W. and dipping 65° W., 

whose throw is about 200 feet at its most southeasterly exposure 

but apparently increases to the northwest, as the displacement 

of the Ochre Mountain and Manning Canyon contact in that 

direction is obviously greater. The fault is cut by the eastward-dipping fault that passes through Gold Hill, and it cannot 

be identified on the footwall side of that fault. A smaller fault 

to the north strikes N. 35° W, and dips 70° W. Its throw is 

roughly 150 feet. Both of these faults are older than the 

quartz monzonite intrusion. 

The remaining fault in this region is that which forms the 

contact between the sediments and the intrusive on the east 

side of the southern tip of the roof pendant. This fault cannot 

be recognized at the surface but was found in the tunnel 500 

feet south of the portal of the Copperopolis (Ida Lull) mine. 

In this tunnel the fault contact is exposed 75 feet from the portal and here strikes N. 12° W. and dips 60° W. The sediments 

on the hanging-wall side are. brecciated for 25 feet away from 

the fault, and the quartz monzonite is intensely crushed throughout most of its exposure in the tunnel. It is uncertain how far 

north the fault forms the contact, because of the lack of exposures, and for this reason it is difficult to give even a minimum 

figure for the throw. 

Mutual relations of the structural features.-The Ochre Mountain block furnishes the most complete record of the structural 

history of the quadrangle. 

The first stage of the first cycle is represented by the minor 

thrusts and folds on the south side of Ochre Mountain and by 

the folds in the roof pendant north of Clifton. These localities 

are the only ones in which structural features of this age have 

been recognized. Normal faults belonging to the second stage 

are definitely present on the south side of Ochre Mountain, 

where they are cut by faults of the second cycle. The assignment of other normal faults in the block to this group is less 

certain. 

No major folds that were formed in the second cycle are 

shown in the block, but the prevailing easterly dip suggests 

that the region forms the western limb of a major anticline. 

Several minor transverse faults of this age were also recognized. 

The normal faults formed during the second stage of the cycle 

seem to be characterized by large throws. On the south side 

of Ochre Mountain two of them form a graben. 

The Ochre Mountain thrust is the major structural feature 

of the third cycle. The North Pass thrust of this age is not 

exposed in the block, but the beds of the central facies of the 

Carboniferous, which are above that thrust, are widely exposed, 

and the North Pass thrust must therefore underlie the region. 

Several low-angle transverse faults of this age are exposed on 

Ochre Mountain and offset some of the older faults. The normal faults of the second stage of the third cycle are neither 

numerous nor of large throw. 

East-west transverse faults of the fourth cycle are found at 

both the north and south boundaries of the block. The northern transverse fault is coextensive with a number of .. northeastward-striking faults, some of which are reve~se faults, 

and the two kinds of faults are considered to be contemporaneous, on the basis of evidence from the vicinity of the Garrison Monster mine, to the north. These faults cut off all the 

older ones . 

...-~...--.-----------------------~ 
78 

• 


GOLD HILL MINING DISTRICT, UTAH 

Some large normal faults that affect the sedimentary rocks, 

of this block along the Lincoln Highway south of Gold Hill 

are younger than the structural features of the fourth cycle and 

are thought to be related to the quartz monzonite intrusion. 

They have no influence upon the present topography, however, 

and are therefore older than the western border fault along the 

west base of Ochre Mountain. 

DUTCH MOUNTAIN BLOCK 

The geographically more or less isolated mass of Dutch Mountain is bounded on the west by a gravel-filled valley that conceals a normal fault of large throw and on the south by a wedge 

of quartz monzonite that separates it from the Ochre Mountain 

block. 

The most pronounced structural feature in the Dutch Mountain block is the northern continuation of the Ochre Mountain 

thrust, which can be traced, with only two interruptions, for 

the length of the block. North of Pool Canyon the thrust forms 

the contact between Carboniferous fprmations and earlier Paleozoic rocks (secs. C-C' and D-D'), but south of the canyon 

the central facies of the Carboniferous lies beneath the fault 

(sec. E-E'). A transverse fault earlier than the thrust is the 

cause of the change in the overridden formations. Both the 

Carboniferous and the earlier Paleozoic rocks beneath the thrust 

are cut by numerous normal faults that are also earlier than the 

thrust. A few normal faults, however, are later, but some of 

these have utilized the lines of earlier faulting. At the north 

end of the block the thrust is also displaced by an east-west 

transverse fault. A group of faults striking east-northeast with 

,either reverse or normal relations are associated with this tr&nsverse fault, and faults of similar strike are found to the EOuth, 

where they also cut the thrust fault (secs. A-A' and B-lJ'). 

Relatively few notable faults have been found in the overriding 

block of Carboniferous rocks on the west slope of Dutch Mountain. Those that are present, however, give evidence of a complex history, in that the same fault has been the site of rene'wed 

movements of both reverse and normal character. The teds 

between the faults are generally folded on a small scale (sec. 

F-F'). 

Ochre Mountain thrust 80uth oj Pool Canyon.-The segment 

of the Ochre Mountain thrust east of the normal fault that 

terminated on the north the exposures of the thrust in the Ochre 

Mountain block (p. 73) must be concealed by the gravel west 

of the divide south of Dutch Mountain. The central facies of 

the Oquirrh formation crops out on hill 6286, north of the divide, 

and the western facies is exposed to the northwest and west. 

The exact position of the thrust in the intervening gravelcovered area is uncertain. The thrust outcrop is shifted at 

least a mile eastward by a northwesterly fault that erops out 

about 1,000 feet north of hill 6286. 

The offset segment north of the fault is the most southerly 

exposure of the thrust in the Dutch Mountain block. On the 

east side of hill 6566, three quarters of a mile northeast of benchmark 5885 on the Ferber Road the thrust appears to be of 

minor throw, as Ochre Mountain limestone forms both walls. 

The only difference apparent between the limestones on the 

two sides of the fault is the noticeably greater metamorphism 

of the beds below the thrust. The magnitude of the fault is 

shown, however, by the fact that the Ochre Mountain limestone 

above the thrust is conformably overlain by the western facies 

of the Pennsylvanian formations, but belbw the fault it is associated with the central facies. Sandstone beds belonging to 

the basal portion of the central fa~ies of the Oquirrh formation 

occur beneath the thrust less than 1,000 feet north of the most 

southerly exposure of the thrust, and the Woodman formation 

takes the place of the Ochre Mountain limestone immediately 

above the thrust. These relations continue northward for about 

a third of a mile, to a point where the outcrop of the thrust is 

interrupted by the mass of quartz monzonite at the head of Pool 

Canyon. 

Ochre Mountain thrust in Pool Canyon.-The thrust is also 

exposed northeast of the quartz monzonite mass in Pool Canyon, 

where the Madison limestone lies above the thrust, and metamorphosed dolomites, thought to belong to the Laketown dolomite, below it. The altitude of the thrust also differs on the 

two sides of the intrusive, being about 300 feet lower to the 

northeast. A transverse fault that follows Pool Canyon and 

may be called the Pool Canyon transverse fault appears to have 

produced these changes in the relations of the thrust. The 

contact between this transverse fault and the thrust is concealed 

by the quartz monzonite, but it seems certain that the transverse 

fault is older, for it cannot be found in the beds overlying the 

thrust northwest of the quartz monzonite area. 

The way by which a change in the formations above the thrust 

was aceomplished is shown by the exposures of the Woodman 

formation that surround the quartz monzonite. Northeast of 

the intrusion the Woodman formation conformably overlies the 

Madison limestone and dips at low angles to the north and west. 

At the northwestern tip of the intrusion, which is in line with 

the prolongation of the transverse fault, the beds of the W oodman show abundant minor faulting and shattering and have 

locally erratic dips. To the southeast, along the border of the 

intrusion, the bedding is concealed in most places but is clearly 

vertical at the summit of Woodman Peak. From this point 

southeastward the dip changes to steep southeast and the Ochre 

Mountain limestone is found above the Woodman. In the 

Ochre Mountain the dip continues to decrease to the southeast 

and passes through horizontality to a low northwesterly dip 

where the contact of the Ochre Mountain and the Woodman is 

again exposed on the ridge south of Pool Canyon: There are 

thu!> a sharp anticline and a low syncline southwest of the intrusive and a gentle monocline northeast of it. 

These relations indicate that the overriding thrust plate 

suffered a considerable disturbance where it crossed the older 

transverse fault. There must have been some rupturing in the 

thrust plate along the line of the older fault to account for the 

difference in structure shown on the two sides of Pool Canyon, 

but the absence of a major fracture in the Woodman formation 

along the prolongation of the transverse fault suggests strongly 

that the greater part of the variation was accomplished by 

warping. 

It seems improbable that the Pool Canyon transverse fault 

could have exerted so strong an influence upon the thrust unless 

the thrust plate were moving over a surface whose topography 

had been influenced by the transverse fault. This conclusion 

appears to be confirmed by the fact that the greater disturbance 

in the beds above the thrust is found southwest of the transverse 

fault, the side that is about 300 feet higher. As the sandstones 

and limestones making up thc Oquirrh formation southwest of 

the transverse fault are much less resistant to erosion than the 

massively bedded dolomites to the northeast, it would appear 

that relatively little time could have elapsed between the formation of the transverse fault and the Ochre Mountain thrust. 

Ochre Mountain thru8t between Pool Canyon and the Garri80n 

Monster mine.-North of Pool Canyon the thrust may be readily traced without serious interruption to the north side of Dutch 

Mountain. The Madison limestone overlies the thrust in this 

series of exposures, but various formations of pre-Devonian age 

underlie it. From Pool Canyon to the south side of Tribune 

Gulch the outcrop of the thrust changes its trend from east to 

northeast, and in this distance it is cut by several faults whose 

throws are less than 100 feet and which are not shown on plate 

3. On the south side of Tribune Gulch the thrust is cut by two 

faults with northeasterly strikes. The more southeasterly of 

these has eaused the repetition of the thrust outcrop on the 

ridge at an altitude of 6,555 feet. 
GEOLOGIC STRUCTURE 79 

A northwesterly fault that follows Tribune Gulch offsets the 

thrust about 1,000 feet to the northwest. The vertical movement along this fault required to accomplish the observed offset 

of the thrust is only 300 feet, but the displacement shown by the 

beds beneath the thrust requires a vertical drop of more than 

600 feet. This discordance suggests that there were two stages 

of movement along the fault, but the observed relations might 

equally well be explained by a dominant horizontal movement. 

This explanation is probably the correct one, as exposures of the 

fault in Royal Gulch, to the north, exhibit pronounced horizontal striae (p. 82). 

Another large offset ill the thrust outcrop is found in the 

vicinity of thc Spotted Fawn mine. In this region several 

branches of the Spotted Fawn normal fault cut the thrust. 

The vertical displacements of the thrust along these faults are 

.. small, but some of them have throws of 2,000 feet or more in 

the overridden rocks. These faults are unlike the fault described in the preceding paragraph, however, in that the discordances cannot be reconciled by postulating horizontal 

movement along the faults, and they must therefore have been 

active at more than one period. 

North of the Spotted Fawn mine the thrust is interrupted at 

only a few places by minor faults and may be readily traced to 

a point within a short distance west of the old camp of the 

Garrison Monster mine, where it is cut off by one of the faults 

in the Garrison Monster transverse fault zone. Throughout 

this distance Madison limestone lies above the thrust and Upper 

Cambrian dolomite below it. 

The Madison limestone above the thrust throughout this 

region dips at very nearly the same angle as the thrust. The 

progressive thinning of the limestone northward, however, shows 

that there is a slight discordance. The only place where a 

notable discordance was observed is near the north end of the 

main outcrop of the thrust, in the region between it and the 

exposures of the thrust in Royal Gulch. In this region, which 

is considerably faulted, there is a sharp asymmetric anticline 

in the Madison limestone that has resulted in a considerably 

greater thickness of the limestone than normal being present 

above the thrust. 

Ochre Mountain thrust near Garrison Monster mine.-North 

of the Garrison Monster transverse fault a thrust that is 

probably the continuation of the Ochre Mountain thrust is 

exposed a short distance west of the new Garrison Monster 

camp. In this region the Woodman formation lies above the 

thrust and Upper Cambrian dolomites beneath it. The thrust 

may be traced northward for more than a mile, beyond which 

it is concealed by gravel. 

"Window" in Royal Gulch.-The erosion of Royal Gulch on 

the north slope of Dutch Mountain has provided additional 

exposures of the Ochre Mountain thrust a short distance west 

of the main outcrop (secs. B-B' and C-C'). In this region the 

thrust is cut by northwesterly faults that appear to be continuations of the faults that cut the thrust in the vicinity of the 

Spotted Fawn mine. These faults cause offsets of the thrust 

outcrop of a few hundred feet, but like their probable continuations near the Spotted Fawn mine, have very different effects 

in the overridden formations. At least two northeasterly faults 

related to the Garrison Monster transverse fault also cut the 

thrust in this region. 

Either the Fish Haven dolomite or the Laketown dolomite 

underlies the thrust throughout a greater part of the "window." 

In several places the contact between these two formations is 

transgressed by the thrust. Madison limestone lies immediately 

above the thrust throughout the exposure. 

Ochre Mountain thrust along north edge of Dutch M ountain.-At 

several places west of the mouth of Accident Canyon, on the 

north side of Dutch Mountain, a low-angle fault is exposed 

separating lower Paleozoic formations, ranging from Cambrian 

to Devonian, from the overlying Woodman formation. The 

gravel that covers much of the area enclosing the exposures of 

the fault conceals its outcrop for considerable distances. The 

fault is thought to be a westward continuation of the Ochre 

Mountain thrust, as its stratigraphic relations are the same as 

those shown along the east side of Dutch Mountain, and just 

east of the mouth of Accident Canyon the probable continuation 

of the fault is less than hiill' a mile from outcrops of the thrust 

in the "window" in Royal Gulch. The thrust has a pronounced 

northerly dip in this region, which is probably due to the close 

proximity of the westward extension of the Garrison Monster 

transverse fault, as the dip appears to be steepest in those outcrops nearest the transverse fault (sec. F-F'). Several normal 

faults cut the thrust to the northwest, and one of them terminates the series of exposures on the west. 

Thrust plates associated with Ochre Mountain thrust.-Locally 

relatively thin thrust plates are associated with the Ochre 

Mountain thrust. They il-re in some respects similar to those 

found on Ochre Mountain (p. 73) and to those related to 

the North Pass thrust in North Pass Canyon (pp. 67-68). One 

of these plates, composed of Upper Cambrian dolomite, lies 

beneath the easternmost exposure of the main thrust north of 

the Spotted Fawn mine. Bedding planes are preserved in 

many places in the plate, and their discordance not only with 

the bedding in the Middle Cambrian beneath but also with 

both the upper and lower c~ntacts of the plate shows conclusively that the block has a tectonic origin. The plate has a 

thickness of about 300 feet on the steep slope north of the 

7,333-foot point on the ridge line of Dutch Mountain and near 

the Garrison Monster mine, but elsewhere it is much thinner. 

It appears to have a rather slight areal extent, as it was not 

recognized in the "window" of Royal Gulch. In Royal Gulch, 

however, the Upper Cambrian is beneath the thrust in its 

normal stratigraphic position on the west limb of a northeastward-trending anticline. It seems probable that the thrust 

plate of dolomite is a continuation of these beds which has 

overridden the less resistant underlying Middle Cambrian 

during the period of overthrusting. The relations are closely 

similar to those in North Pass Canyon, where the presence of 

plates of resistant rocks beneath the main North Pass thrust 

is considered to indicate that both the main thrust and the 

plates moved forward over an older erosion surface (p. 57). 

Several minor thrusts in the rocks above the Ochre Mountain 

thrust are exposed in the vicinity of the Garrison Monster mine. 

Some of these thrusts in the Woodman formation can be seen 

along the Lake Bonneville beach at 5,200 feet, west of the portal 

of the tunnel (altitude 4,894 feet) at the new camp. One of 

these thrusts (pI. 7, D) clearly reveals minor folds in the overridden beds. Another thrust, which encircles the summit 

between the old and the new Garrison Monster workings, 

brings Madison limestone over the Woodman formation. It 

may be a continuation of one of the minor thrusts exposed to 

the north. 

Appearance of Ochre Mountain thrust.-In almost all places 

it is difficult to determine the precise horizon of the thrust, and 

the location shown on the map represents a halfway point 

between beds that may be recognized as belonging to formations 

above and below it. The intervening rock, which in many 

places reaches a thickness of 20 feet and is rarely less than 10 

feet, is so thoroughly recrystallized that it is impossible either 

to 'distinguish characteristic sedimentary structure or to choose 

a dividing plane. Angular fragments of any size, or a fault 

breccia, can be distinguished megascopically in only a few 

places, although there is, in many places, a slight streakiness 

parallel to the thrust. A typical specimen from Royal Gulch is 

a light grayish-brown rock in which thin bands and lenses of a 

white coarser-grained calcite alternate with thicker bands of 

grayish-brown fine-grained carbonate. The cleavage planes of 

the white calcite reach an eighth of an inch in diameter, and 

locally tiny remnants of a bluish calcite may be distinguished 
GOLD HILL MINING DISTRICT, UTAH 

within them. Optical tests on crushed fragments of the finergrained material indicate that it is in large part dolomite. 

Under the microscope the coarsely crystalline calcite is seen to 

be the older mineral. Individual crystals are rather turbid and 

are commonly twinned. Curving cleavage planes are strongly 

developed and are characteristic of this stage. The white calcite is embayed and veined by a clear, unstrained carbonate 

mineral, most of which, as noted above, is probably dolomite. 

This is the material that is grayish brown in the hand specimen, 

and the microscope shows that the color is due to the presence 

of a brown mineral, probably iron oxide, around the borders of 

the dolomite crystals. Similar brown material surrounds fragments of the older calcite where it is i:t;l contact with the younger 

crystals. A fcw laths of S;;lricite are present in some places with 

the iron oxides. Small blebs and stringers of fine-grained 

quartz show iiltense shearing and undulose extinction. The 

relation of the quartz to the white calcite is not clear, but it is 

clearly vcined by the dolomite. 

The features observed in this specimen are interpreted as 

follows: The white calcite crystals are thought to be sheared 

and enlarged crystals of the original limestone. Enlargement 

~e:ms required, as thcy are of larger ~iameter than any seen in 

any of the unaltered limestones. The quartz stringers and 

lenses are considered to have formed as a result of the shearing 

of cherty and sandy portions of the limestone. Partial recrystallization of the quartz and enlargement of the white calcite 

crystals resulted in their having somewhat anomalous relations 

to each other. These two components of the rock mark the 

initial stages of the thrusting. As the movement continued, 

shearing became localized along planes parallel to the fault, and 

on these planes recrystallization accompanied by expulsion of 

the impurities in the original grains occurred, resulting in the 

formation of the clear unstrained crystals with their boundaries 

of iron oxides and sericite. The presence of so much dolomite 

apparently indicates that there must have been some transfer 

of material during recrystallization, the magnesium being 

derived from the overridden dolomites. Such a transfer was 

probably accomplished by circulating solutions, as the absence 

of extensive cataclastic structure argues against anhydrous 

conditions during the thrusting. 

Folding of Ochre Mountain thrust.-Variations in the altitude 

of the thrust outcrop that are independent of later faulting 

indicate that it has been warped into several minor folds. A 

well-defined anticline is shown by the thrust north of the 

Spotted Fawn mine, the altitude of the thrust outcrop increasing 

from 6,600 feet or less to about 7,200 feet on the divide between 

Spotted Fawn Gulch and Busby Gulch, and decreasing west of 

the divide, as shown by the "window" in Royal Gulch and the 

Madison limestone outcrops in the gulches to the south. The 

anticlinal axis must strike about northeast and be located 

approximately along the ridge line of Dutch Mountain. 

Beneath Accident Canyon the thrust must have an altitude 

of 4;500 feet or less, as shown by the absence of exposures of 

Madison limestone south of the east-west fault that extends 

along the north side of the mountain here. Farther west, however, the thrust is again exposed at an altitude of about 5,100 

feet, showing that a synclinal fold must occur in the vicinity of 

Accident Canyon. 

The folds in the thrust are thought to be related to the Garrison Monster transverse fault (p. 59). 

Magnitude of the thrust.--The distance between the easternmost and westernmost exposures of the thrust is about 4 miles, 

slightly less than was found in the Ochre Mountain block (p. 74). 

This is a minimum figure for the amount of movement along 

the thrust, however, and the tot.al th{ow must be much larger. 

Pool Canyon trans~erse fault.-The existence of a large fault 

in Pool Canyon is shown by the Qqcurrence of lower Paleozoic 

formations beneath the Ochre Mountain thrust on the north 

side of the canyon and of Carboniferous formations on the 

south side. Exposures of the fault, which has been called the 

Pool Canyon transverse fault, are poor and of small extent, 

most of its projected course being concealed either by gravel 

or by younger intrusive rocks. 

The fault does not cut the rocks above the thrust, but its 

intersection with the thrust in the northwestern part of Pool 

Canyon is concealed by a mass of quartz monzonite. The 

fault is exposed for a distance of about 2,000 feet in the central 

part of the canyon, but the extensive metamorphism of sedi· 

ments on each side makes it difficult to distinguish the fault 

plane. A small intrusion is present along the fault in this 

region, and its linear northern boundary is thought to coincide 

with the fault plane. A prospect pit at this locality shows 

that the contact dips. steeply to the south. In the lower reaches 

of Pool Canyon another body of quartz monzonite has been 

intruded along the fault, but its continuation is shown by the 

beds exposed on each side of the canyon. 

Another group of outcrops is found in the vicinity of the 

Rube mine. The westernmost outcrop of the fault in this 

region is just north of hill 5057. Here the Prospect Moulltain 

quartzite north of the fault is in contact with Ochre MOUIltain 

limestone. A prospect tunnel on the northwest side of the low 

ridge apparently parallels the fault immediately to the soUttl. 

The tunnel shows thoroughly crushed rock but does not give 

any definite indication of the dip of the fault at this point. 

A small outcrop of Ochre Mountain limestone about- 1,200 

feet to the northwest, which is surrounded by, gravel, indicates 

that the transverse fault must be offset to the north at least 

700 feet. The fault causing the offset is shown on the map with 

a north-south strike, but there is no evidence to prove that it 

may not strike northeast. Another offset of about the same 

amount is required by exposures of the transverse fault west 

of the Rube mine. This offset is thought to be the result of a 

westward·dipping fault exposed in the Ochre Mountain limestone on the Ruby claim, to the south. If this fault really 

is the one causing the offset and the movement along it is of 

the normal type, the transverse fault must dip to the south, 

as it does in Pool Canyon. It is possible, however, that the 

offsetting fault may have a northeast strike; if so, it would crop 

out beneath the gravel of Gold Hill Wash. 

Another offsetting fault must be present in the gravel-covered 

slope west of hill 5556, east of the Rube mine. This fault must 

be older than the intrusion of quartz monzonite, as no trace 

of it was found to the south. East of the offset the transverse 

fault cannot be exactly locatcd for some distance. but its 

approximate position is shown southeast of hill 5556 by an 

isolated outcrop of Pennsylvanian limestone in close proximity 

to one of Prospect Mountain quartzite. There are probably 

no further offsets concealed by the gravel in the area to the 

east. The easternmost exposure within the quadrangle is found 

about half a mile west of the Christmas mine. Here the transverse fault is cut off by a fault trending nearly due north, but 

the amount of displacement i& not known. 

There is no evidence by which the amount of movement 

along the Pool Canyon transverse fault can be determined. 

The stratigraphic throw ranges from 10,000 to 20,000 feet, as 

shown by the formations on each side. These figures, however, 

do not take into account the facts that the,Carboniferous rocks 

south of the fault belong to the central facies and lie above the 

North Pass thrust, and that the lower Paleozoic formations to 

the north appear to be a continuation of the similar beds south 

of North Pass Canyon that are below the North Pass thrust: 

Relation of PooZ Canyoo transverse fault to North PaBs thrust.­

The occurrence of the central facies of the Carboniferous formations on the south side of the Pool Canyon transverse fault 

shows that the North Pass thrust must have extended into this 

structural block, but· the quartz monzonite intrusion and the 
GEOLOGIC STRUCTURE 81 

gravel that occurs along the eastern portion of the block combine to conceal its outcrop. As the rocks north of the transverse fault are similar to those that were overridden by the 

North Pass thrust, the transverse fault marks the northern 

limit of the present exposures of the North Pass thrust -plate. 

n the suggestions made on page 78 are correct-that the 

Ochre Mountain thrust moved over the then existing surface 

and is only slightly younger than the Pool Canyon transverse 

fault--the transverse fault must have limited the thrust plate 

on the north at the time of thrusting, for otherwise the segment 

of the North Pass thrust plate north of the Pool Canyon fault 

would have been preserved beneath the Ochre Mountain thrust. 

This conclusion, together with the apparent limitation of the 

North Pass thrust on the south by a parallel transverse fault 

(p. 57), indicates that the North Pass thrust had a relatively 

slight extent along its strike in comparison with the amount 

of horizontal movement that took place along it. 

Folding in rocks beneath Ochre Mountain thrust.-The lower 

Paleozoic rocks along the eastern front of Duteh Mountain 

form the western limb of a major anticline. The axis of the 

fold probably roughly coincides with the eastern base of the 

mountain, to judge from the prevailing flat dips and local east 

dips found there. The scattered exposures of the rocks beneath 

the thrust along the northern base of the mountain suggest that 

a minor anticline and syncline are superposed on the major 

fold in this region. These folds appear to be independent of 

the warping shown by the Ochre Mountain thrust. 

Faulting below Ochre Mountain thrust south of Pool Canyon 

fault.-South of Pool Canyon the rocks underlying the Ochre 

Mountain thrust belong to the central facies of the Carboniferous. The two most prominent faults in this region, which 

strike west-northwest, have acted to enclose a band of the 

Oquirrh formation between two bands of the Ochre Mountain 

limestone. Minor faults, striking west of north, are made 

apparent in the central belt by offsets of the lower contact of 

the Oquirrh formation and are, in part at least. younger than 

the west-northwest fault, which they displace. In the central 

belt the Oquirrh formation and the Ochre Mountain limestone 

are separated by less than 100 feet of black shale that has been 

referred to the Manning Canyon formation. Such a thickness 

is much less than that normally shown by the Manning Canyon, 

and it seems probable that here, as in some other places, it has 

been thinned by overriding during thrusting. The thinning at 

this place may perhaps be correlated with a marked thickening 

to the southwest, just south of the Ferber Road. The two 

west-northwest faults are parallel in strike to the large transverse fault in Pool Canyon and are probably subsidiary fractures developed at the same time as the main fault. The 

northern of the two faults has been the site of movement 

sufficient to give an apparent vertical throw of at least 4,000 

feet. 

Spotted Fawn normal-fault zone.-A branching normal fault, 

which separates Lower and Middle Cambrian beds on the 

northeast from younger formations on the southwest, extends 

in a southwesterly direction from the vicinity of the Spotted 

Fawn mine. It may be traced to the Borth side of Tribune 

Gulch, beyond which it is concealed by gravel. 

At the most southeasterly exposures, near the mouth of 

Tribune Gulch, the fault separates Prospect Mountain quartzite 

on the northeast from Upper Cambrian dolomite on the southwest. Though poorly exposed, it is, without much doubt, a 

single fracture. On the small 5,384-foot hill a 40-foot lenticular 

dike of quartz monzonite has been intruded along the fault, and 

a prospect pit on the southwest side shows the dip of the contact 

to be 58° SW. It is probable that this figure approximates the 

dip of the fault plane in this region. The fault continues as a 

single fracture without change in stratigraphic relations for 

more than 4,000 feet to the northwest. It is offset from 100 to 

400 feet by four northeastward-striking faults that dip to the 

northwest. In all four places the outcrop of the fault is shifted 

to the southwest in the hanging wall of the younger faults, 

indicating a reverse movement along them. 

North of the fourth offset, at a point where the fault is 

crossed by latitude 40°12'30", it splits into two branches-a 

minor one separating the Prospect Mountain quartzite from 

the Cabin shale and· the Busby quartzite and a main branch 

separating those two formations from the Upper Cambrian. 

The contact between the shale and the Busby quartzite in the 

block between the two branches is clearly the result of overriding by the quartzite, as shown by the discordance in dip 

between the two formations and also by the absence of the 

characteristic concretionary bed that normally occurs at the top 

of the shale. 

About 500 feet north of the junction both branches are 

shifted about 100 feet to the west by the northeasterly reverse 

fault that causes a repetition of the outcrop of the Ochre Mountain thrust (p. 78). Two more branches are found north of the 

offsetting fault--one relatively small, within the Busby quartzite, and one that brings in a wedge of Middle Cambrian limestone between the Busby quartzite and the Upper Cambrian. 

The latter branch and the main branch are, a short distance 

father north, shifted about 300 feet to the east by still another 

northeasterly fault, along which, however, the displacement is 

apparently of the normal type. The two eastern branches cannot be confidently distinguished north of the intersecting fault, 

but there are two nearly parallel faults to the west, which are, 

in all probability, new branches. The throw on both of them 

is small, as is shown by the displacement of the Fish Haven 

dolomite. 

Several of the branches cut the Ochre Mountain thrust. 

Along three of them the displacement of the thrust is notably 

at variance with the displacement of the beds beneath the 

thrust, indicating that the Spotted Fawn fault zone has been 

active during more than one structural cycle. Thus the most 

southwesterly branch that cuts the thrust drops the thrust 

several hundred feet to the southwest and drops the beds 

beneath the thrust an approximately equal amount to the northeast. The main branch of the fault that crops out a few hundred 

feet west of the Spotted Fawn shaft at 6,543 feet has a throw of 

200 feet or less as measured by the thrust and at least 2,000 feet 

as measured beneath the thrust. The most easterly fault has 

similar relations. It offsets the thrust less than 100 feet. but 

in the beds beneath the thrust it separates Middle Cambrian 

limestone from Cabin shale and Busby quartzit_relations 

indicating a much larger throw. 

The total throw along the Spotted Fawn fault zone in the 

beds beneath the thrust amounts to about 4,000 feet. 

Faults in Royal Gulch "window."-The branches of the 

northwesterly Spotted Fawn fault are also exposed in Royal 

Gulch. Here, as on the east side of Dutch Mountain, they have 

been the sites of post-thrust as well as pre-thrust movement. 

There are in addition several northeastward-striking faults 

younger than the thrust. Some of these cut the post-thrust 

portions of the northwesterly faults, but others are cut by them. 

The northwesterly continuation of the main branch of the 

Spotted Fawn normal fault illustrates most of the complexities 

of the faulting. Near the head of Royal Gulch it cuts the Ochre 

Mountain thrust and drops the portion to the southwest several 

hundred feet. It also offsets the Madison limestone above the 

thrust in such a way as to exhibit the local flexure in that 

formation (p. 79). Near the prospects on the north side of 

Royal Gulch it is cut and offset by a northeasterly fault with a 

low northwestward dip. The faulted segment causes a repetition 

of the Ochre Mountain thrust outcrop, which is 100 to 200 feet 

lower on the southwest side. Beneath the thrust. however, 

the beds on the northeast side have been dropped; Upper 

Cambrian dolomite is exposed on the northeast immediately 

below the thrust, and Laketown dolomite on the southwest, 

-
82 GOLD HILL MINING DISTRICT, UTAH 

showing a pre-thrust throw that amounts to 1,000 feet or more. 

Near the mouth of the gulch the fault shifts a northeasterly 

fault several hundred feet. The northeasterly fault is similar 

in strike and dip to the one that cuts the Spotted Fawn fault 

to the southwest. 

The probable continuation of the fault in Tribune Gulch 

whose movement is thought to have been dominantly horizontal 

(p. 79) is exposed in Royal Gulch. The tunnel at 5,593 feet 

cuts this fault and follows it for several feet. Throughout this 

distance the polished fault plane shows deep horizontal grooving. 

Minor faults between Spotted Fawn and Pool Canyon faults.­

The triangular area of rocks ranging from Upper Cambrian to 

Silurian between the Spotted Fawn normal fault, the Pool Canyon transverse fault, and the Ochre Mountain thrust show widespread minor faulting. Such faulting is apparently concentrated in the regions in which the Fish Haven dolomite crops 

out (pI. 2), for this dolomite is one of the few reliable horizon 

markers by which faults may be distinguished from zones of 

shattering. It is probable that more intensive field work would 

show the presence of additional outcrops of the Fish Haven 

dolomite in this region, especially in the strip of country between 

the two northeasterly faults on the two sides of hill 6279, on 

the south side of Tribune Gulch. 

The faults in this triangular area strike in three general directions. The northeasterly faults are the youngest and include 

both reverse and normal faults. The other faults strike either 

north or west of north. The relations between these two groups 

are not conclusive, but farther north those striking west of 

north appear to be the younger. They are for the most part 

older than the thrust, however, but along some of them there 

has been renewed movement after the thrusting. These faults 

are essentially parallel in strike to the large normal fault just 

described and may have been formed at the same time. The 

altern:.te hypothesis, however, that some of the faulting was the 

direct result· of the overthrusting whereby original slight elevations of the overridden surface were eliminated by being downfaulted, is suggested by the position of the outcrops of the Fish 

Haven dolomite on the south side of Tribune Gulch. 

Faults beneath the thrust north of the Spotted Fawn fault.­

The rocks beneath the thrust on the footwall side of the Spotted 

Fawn fault are all of Cambrian age, chiefly Lower and Middle 

Cambrian. The Prospect Mountain quartzite forms a large 

part of these rocks, and its uniform character and poor exposures 

prevent any attempt to correlate the faults exposed at its upper 

contact with those along the east base of Dutch Mountain in 

the places where shale members crop out. The exposures of 

the shale are relatively few, and are all partly concealed by 

gravel, but they show the same kinds of faults as are found along 

the upper contact of the quartzite. One of the largest of the 

faults along the east base of Dutch Mountain terminates on the 

south the exposure of the shale member north of the road to the 

Spotted Fawn mine. The shale member was not recognized 

south of the road, and the throw along this fault must therefore 

be about 1,000 feet. 

In the interval between the upper boundary of the Prospect 

Mountain quartzite and the Ochre' Mountain thrust several 

faults have been recognized by means of the distribution of the 

Cabin shale and Busby quartzite. To the north, in the wide 

outcrop of undifferentiated Middle Cambrian rocks, exposures 

are poor and faults are difficult to trace. 

Several faults are exposed in the vicinity of the Spotted Fawn 

mine in addition to the Spotted Fawn normal faults. One of 

these is parallel to and on the north side of the canyon bottom 

southeast ofthe mine workings. It is unusual'in that it is one 

of the few faults on Dutch Mountain that dips to the northeast. 

The fault drops the thrust 150 feet on the east side and causes 

a somewhat smaller but similar displacement of the upper contact of the Prospect Mountain quartzite beneath the thrust. 

Between these two points. however, the Cabin shale forms the 

footwall of the fault, and in the hanging wall are found succes· 

sively Cabin shale, Busby quartzite, and a portion of the Abercrombie formation, representing vertical displacements ranging 

from 0 to about 1,000 feet. This, combined with the presence 

of Middle Cambrian limestones beneath the thrust on the footwall side of the fault, implies that there must have been some 

pre-thrust movement along this fault, in spite of the apparent 

concordance in throw at its intersections with the thrust and 

with the upper contact of the Prospect Mountain quartzite. 

The exposures in the main tunnel of the Spotted Fawn mine 

indicate the presence of a minor thrust that is not readily recog· 

nized on the surface. The rocks exposed are highly metamor· 

phosed beds of the Busby quartzite. The eiposures on the 

surface and in two shallow shafts above the tunnel (see fig. 27), 

however, are Middle Cambrian limestones. The attitude of 

the two sets of exposures, together with the details of their 

distribution, show that they must be separated by a nearly 

horizontal fault. This fault is probably represented by 6 feet 

of breccia exposed at the top of the vertical raise in the northern 

branch of the tunnel, and its outcrop is probably just below the 

dump 100 feet north of the tunnel portal. The flat fault appears 

to offset the most easterly branch of the Spotted Fawn normal 

fault about 100 feet. No such offset was found along the eastward·dipping fault, and it is possible that the minor thrust is 

earlier. 

Other evidences of horizontal movement in this region are 

abundant. In the tunnel the individual beds of quartzite are 

truncated by minor flat faults. Even more striking is the local 

overriding of the Cabin shale by the thin strip of Busby quartzite 

exposed in the footwall of the east branch of the Spotted Fawn 

fault. The best example of this feature was found about 1,400 

feet east of south from the cabin at the Spotted Fawn. 

There are undoubtedly many other nearly flat faults in the 

overridden formations between the Spotted Fawn and Garrison 

Monster mines, but extremely detailed work would be necessary 

to recognize and trace them. The unusually small thickness 

of the Busby quartzite and Cabin shale in Busby Canyon 

(pp. 7-8) points to this conclusion, as does the difficulty that 

was met in attempting to reconcile contradictory evidence as to 

the amount of displacement along many of the minor faults. 

Only two other faults in the overridden block, soutb of the 

Garrison Monster mine, merit detailed description. One of 

these is the northwesterly normal fault about 1,000 feet south 

of the point at 6,785 feet and 2,500 feet northeast of the Spotted 

Fawn mine. This fault is relatively small, for the throw corresponds to a vertical drop of only 100 feet on the southwest side. 

Its chief interest lies in the fact that it cuts three nearly northsouth normal faults, indicating that there is represented on 

Dutch Mountain a period of normal faulting definitely earlier 

than that of the prevailing northwesterly faults. 

The second fault, or rather fault zone, strikes northwestward 

from peak 6264, on the north side of Busby Gulch. This zone 

is cut by several northeasterly faults, the largest of which is a 

reverse fault with a throw of about 100 feet. The fault zone 

has dropped the beds on the southwest side at least 500 feet and 

is the only one of this group comparable in size with the fault 

that terminates the shale member of the Prospect Mountain 

quartzite north of the road leading to the Spotted Fawn mine. 

If, as seems likely, the two faults are the same, they might serve 

as starting points to determine tile fault pattern in the Prospect 

Mountain quartzite, should a more detailed study of the geology 

be undertaken. 

The eastern portions of sections C-C' and D-D' show the 

more striking features of the overridden rocks. They are somewhat diagrammatic, however, particularly in the almost complete omission of the nearly horizontal minor thrusts that are 

probably rather widespread. 

Garrison Monster transverse fault zone.-The fault zone near 

the Garrison Monster mine illustrates the mechanism of trans­
GEOLOGIC STRUCTURE 83 

verse faulting better than any of the other faults of this type in 

the quadrangle. It appears to represent a line of differential 

movement, north of which shortening was accomplished by 

thrusting and to the south by folding (p. 59 and fig. 8) . 

. The fault zone varies in character from a single steep fracture 

to a group of faults with relatively low dip. 

The simple, steep portion of the fault is best seen south of the 

Garrison Monster inclined shaft, where it separates Prospect 

Mountain quartzite on the south from dolomitized Middle 

Cambrian limestones on the north (sec. A-A'). Eastward from 

this point the poor exposures indicate a swing in strike toward 

the northeast, and east of the tunnel at 4,834 feet, the strike, 

as shown by the scattered outcrops surrounded by gravel, must 

be very close to that direction. At the triple-peaked hill 2,000 

feet southwest of bench mark 4382 on the railroad, the eastward continuation of the fault appears to be cut by a fault 

striking west-northwest. 

West of the Garrison Monster incline, on the south side of 

the fault, the Prospect Mountain quartzite is overlain by the 

Cabin shale and the Busby quartzite. The shale shows pronounced drag effects near the fault, its strike swinging to 

nearly east-west and its dip steepening to more than 40° N. 

The Busby quartzite, however, shows no notable drag but has 

overridden the shale along a low-angle westward-dipping fault, 

which is exposed only close to the transverse fault. On the 

north side of the transverse fault the outcrop of Middle Cambrian beds wedges out westward, and the thrust plate of Upper 

Cambrian dolomite above it is adjacent to the fault. The thrust 

plate of dolomite in turn wedges out within a short distance, 

and at the bottom of the gulch leading to the Garrison Monster 

camp the Ochre Mountain limestone is next to the fault. The 

contact between the limestone and the dolomite must represent 

the Ochre Mountain thrust. Gravel flooring the gulch interrupts the outcrops for a few hundred feet. The dip of this 

section of the fault cannot be directly measured, but both the 

dips in the beds on each side and the effect of the topography 

upon its outcrop indicate that it must dip steeply to the north. 

On the west wall of the gulch the Ochre Mountain limestone 

is in fault contact with Middle Cambrian beds, but the fault 

dips at a moderately low angle (about 40°) to the north. This 

fault has several branches with somewhat lower dips, which 

bring in, with various relations, all the formations that intervene 

between the Ochre Mountain limestone and the Middle Cambrian in the region to the south, where the thrust is essentially 

undeformed. The single steep fracture to the east has thus 

been replaced westward by a fault zone of low dip. The change 

in character coincides with the intersection of the transverse 

fault with the Ochre Mountain thrust. A similar coincidence 

was noted on the south side of Ochre Mountain (p. 71), and 

it was suggested that the low dip of the thrust had caused the 

change in dip of the transverse fault. 

About 1,000 feet east of the mouth of Royal Gulch the northernmost of the series of branch faults disappears beneath the 

piedmont gravel. West of this point the projected course of 

the transverse fault is covered by gravel until the west side 

of the gravel-filled area in Accident Canyon is reached. In 

this distance, however, east-west strikes in the Woodman formation to the south and local nearly east-west fracture zones, 

particularly in the two eastern isolated outcrops in Accident 

Canyon, suggest strongly that the fault is not far distant. On 

the west side of Accident Canyon the projected line of the fault 

corresponds with a fault separating Madison limestone on the 

north and the Woodman formation on the south. The Woodman beds are poorly exposed but are thought to be rather 

closely folded, and the Madison limestone shows rather pronounced drag effects. 

West of another gravel-covered interval the fault is again 

exposed along the base of the linear steep slope west of Accident 

Canyon. Here the Ochre Mountain thrust appears on the 

north side, the Woodman formation resting upon the Laketown 

dolomite. At the point where the steep slope curves northward, however, the fault does not cross the spur, as is shown by 

the continuous exposure of the Ochre Mountain thrust. There 

must, however, be some warping along this general line still 

farther west, because the Ochre Mountain thrust as exposed in 

the isolated outcrops to the north is at a much lower altitude 

than to the south (sec. F-F'). 

Nature and amount of movement along Garrison Monster fault 

zone.-In the vicinity of the Garrison Monster mine the rocks 

north of the transverse fault are believed to have moved relatively eastward about 1?~ miles. This belief is based upon the 

assumption that the westward-dipping fauH; separating the 

Woodman formation from the Ochre Mountain limestone exposed west of the Garrison Monster workings is the same as 

the steeply dipping portion of the Dutch Mountain fault (p. 84), 

to the south. This figure is roughly checked by the position of 

the Ochre Mountain thrust on both sides of the transverse fault. 

It is probable that the transverse fault represents a line of 

differential movement, north of which crustal shortening took 

place along a thrust fault, and south of which shortening was 

accomplished by folding (fig. 8). The evidence for this belief 

is as follows: Thrusting of some sort seems required north of 

the thrust, for the Ochre Mountain thrust, which may be used 

as a horizon marker, is relatively undeformed north of the thrust 

except for a gentle westward dip. As the north side has apparently moved eastward, the crustal shortening must therefore 

have been effected by faulting. The northeastward curvature 

in strike shown by the transverse fault as it is followed eastward 

suggests that the transverse fault itself is passing into a thrust, 

but the absence of adequate exposures in that direction makes 

it impossible to prove the suggestion. 

The folding of the Ochre Mountain thrust south of the transverse fault (p. 80) appears to provide the required amount 

of shortening to the south. The scaled distance along the 

folded thrust in a section nearly 2 miles south of the transverse 

fault showed that there had been half a mile of shortening along 

this line. This amount is only a third of the probable movement along the transverse fault and suggests that the amount 

of compression decreased southward, a suggestion that appears 

to be confirmed by the absence of comparable folding of the 

thrust in Pool Canyon, where the thrust is exposed for some 

distance in an east-west direction, and by the northeast strike 

of the axis of the fold, rather than the northerly strike that 

would be expected if the compression were of equal magnitude 

to the south. 

Probable conjugate faulting related to Garrison Monster fault.­

Two groups of faults that are younger than the Ochre Mountain thrust are present on Dutch Mountain, chiefly south of 

the Garrison Monster fault zone. The faults of one of these 

groups strike northeast and dip northwest. Many of them 

show an apparent reverse movement. The faults of the other 

group strike northwest and dip southwest. They commonly 

follow lines of pre-thrust faulting in the beds below the thrust. 

On some of them the movement has been largely horizontal. 

Although the northeasterly faults commonly cut the northwesterly ones, locally, as in Royal Gulch, the reverse is true. These 

relations suggest that the two groups of faults are essentially 

contemporaneous and form a set of conjugate faults. As some 

of the northeasterly faults appear to change their strike to east 

as they approach the Garrison Monster fault zone and to become 

a part of that zone, it seems probable that the conjugate faulting 

was genetically related to the transverse faulting. 

Similar conjugate faults adjacent to the contempo.raneous 

transverse faults to the south are apparently lacking. A possible explanation for the difference in relations may lie in the 

fact that the Garrison Monster fault has a much smaller strike 

length than the other faults of this character, and that for this 

reason the necessary readjustments in the passive block south 
84 GOLD HILL MINING DISTRICT, UTAH 

of the fault were accomplished by both folding and faulting, 

whereas in the longer transverse faults the necessary shortening 

in the passive block could be accomplished by folding alone. 

Because of their abundance, some of the conjugate faults are 

not shown on plate 3. Where the northwesterly faults of the 

system do not cut the Ochre Mountain thrust, it is uncertain 

whether or not the faultwasactive in pre-thrust or post-thrust time 

or in both. For this reason many of the faults shown on plate 3 

are marked with the symbol for two different structural cycles, 

although most of them were probably active at only one time. 

One of the most persistent of the northeasterly faults has a 

low northwestward dip throughout most of the exposures in 

Royal Gulch and Accident Canyon, but at the floor of Accident 

Canyon its dip is almost vertical (pl. 7, C). 

Dutch Mountain thrust.-The contact between the Ochre 

Mountain limestone and the Woodman formation throughout 

the block is a thrust fault. In most of the region the thrust has 

a low dip, and its presence is shown either by a minor discordance 

in dip between the two formations and rather considerable variations in the thickness of the underlying Woodman formation 

in the higher portion of Dutch Mountain, or by the close folding 

of the Woodman formation below the thrust on the west side of 

Accident Canyon. The thrust dips steeply westward, however, 

in the southern part of Accident Canyon. This steeply dipping 

portion almost certainly connects a flatter portion whose outcrop 

encircles the summit of the mountain and another flatter portion 

exposed west of Accident Canyon, for no other faults were recognized that could bring about the observed relations. 

The steep portion of the thrust must be an original feature 

and not due to later folding. This is definitely proved by the 

absence of such folding in the beds beneath the thrust, as is 

shown particularly by small outcrops of Madison limestone 

close to the steep portion of the thrust at altitudes that closely 

approximate those obtained by projecting the outcrops on the 

east side of Dutch Mountain. 

In the exposures of the Dutch Mountain thrust along the 

northwestern edge of the mountain the interval between this 

thrust and the Ochre Mountain thrust is much smaller than to 

the southeast, beneath the higher parts of Dutch Mountain. 

This is due chiefly to the occurrence of the steeper part of the 

Dutch Mountain thrust between the two localities, but in 

addition there appears to have been some minor warping of the 

Dutch Mountain thrust that is not shown by the Ochre Mountain thrust. The Dutch Mountain thrust must therefore be 

the older of the two. This conclusion is confirmed by the relations of the two thrusts to the Trail Gulch fault, described 

below. The Dutch Mountain thrust is cut off by this fault, 

but the Ochre Mountain thrust is not affected by it. 

In addition to the two major exposures of the thrust, there 

are two smaller isolated outcrops that are considered to be 

continuations of it. One of these is on the south side of Pool 

Canyon southeast of peak 7262, where the Ochre Mountain 

limestone rests with fault contact upon the Woodman formation. 

The thrust here dips notably to the east as a result of the disturbance in the beds above the Ochre Mountain thrust by the 

Pool Canyon transverse fault. The second small outcrop is in 

the vicinity of the Garrison Monster mine. Here a westwarddipping fault that separates Ochre Mountain limestone from the 

Woodman formation is believed to be a continuation of the 

steeper part of the Dutch Mountain thrust offset eastward by 

the Garrison Monster transverse fault. 

Trail Gulch fauU.-The fault in Trail GulCh, on the west 

slope of Dutch Mountain, shows rather noteworthy variations 

in strike, ranging from nearly north in the south-central portion 

through northwest to nearly west in the northern portion. It 

has been traced for about 4 miles and through most of this 

distance forms the boundary between the Oquirrh formation on 

the west and Mississippian formations on the east. The dip is also 

somewhat variable but is in general steep to the west or south. 

The total throw along the fault cannot be measured with any 

confidence, because of the lack of definite horizon . markers on 

either side, and also because to the south it includes the throw 

of the steep portion of the Dutch Mountain thrust. Immediately north of its intersection with the thrust, the throw must 

be equivalent to about 1,000 feet or more of the Pennsyl-< 

vanian plus at least 1,500 feet of the Ochre Mountain limestone. 

The throw appears to be considerably less farther north, however. 

At the extreme south end the total throw is about equal to the 

thickness of the Ochre Mountain limestone, but here the throw 

along the Dutch Mountain thrust is included. 

The chief interest of this fault lies in the fact it has been 

active at least three times. The greater part of the movement 

clearly occurred before the formation of the Ochre Mountain 

thrust, because at its south end it is cut off by the thrust. This 

movement was normal. A second normal movement along the 

central portion of the fault appears to have oCllurred at a comparatively recent time, to judge from the topographic discordance at the fault, the notable influence of the fault upon the 

drainage pattern, and the presence of gravels resting upon the 

mature surface adjoining the fault east of knoll 6518. The 

amount of the later movement, as estimated from the topography, is thought to be about 800 feet (sec. D-D'). 

In addition to these two periods of activity, both of which 

resulted in normal faulting, the fault also appears to have been 

the site of reverse movement at the time the Ochre Mountain 

thrust was formed, but it was not possible to obtain a quantitative idea of the amount, as the evidence is indirect. One 

indication is the abundance of minor folds in the Oquirrh 

formation immediately west of the Trail Gulch fault and the 

absence of such features to the east (sec. D-D'). This appears 

to show that the fault acted as a plane of relief along which 

movement took place while the beds to the west were being 

folded, thus protecting the beds to the east from similar deformation. Another indication is that in the region west I)f Pool 

Canyon nei'ther the fault itself nor the Oquirrh formatil)fi in its 

hanging wall have been affected by the notable defl)rmation 

shown by the thrust and the overlying Mississippian beds at 

the point where the Pool Canyon transverse fault was overridden by the thrust. These relations strongly suggest renewed 

movement along the fault, either of a reverse or transverse 

character, by the beds on its hanging wall. 

In summary, the fault appears to have been first formed as 

a normal fault of large throw after the period of thrusting 

represented by the Dutch Mountain thrust but before the 

Ochre Mountain thrust. During the formation of the Ochre 

Mountain thrust it was again active, but the direction of movement was reversed. Finally, renewed normal faulting occurred 

at a relatively rece.l'lt time. 

Minor structural features in the rocks above the Ochre Mountain 

thrust.-In addition to the minor faults that cut the rocks both 

above and below the Ochre Mountain thrust, there are a few 

minor faults that occur only in rocks above the thrust. One 

of these is a small reverse fault south-southwest of Woodman 

Peak and west of the Trail Gulch fault. This fault dips 45° W. 

and has caused the lower beds of the Oquirrh formation to 

override several hundred feet of the Manning Canyon formation. 

Its relation to the Trail Gulch fault could not be determined, 

and whether it is of the same age as the Ochre Mountain thrust 

or the Dutch Mountain thrust is therefore not known. It is 

terminated on the southwest by a younger fault. 

Folding in this area was largely confined to the beds west of 

the Trail Gulch fault. Gentle folds are also found east of the 

fault, as is shown in section D-D', but are of much less intensity. 

Two well-defined folds occur west of the fault--a .syncline near 

the fault and an anticline farther west. The synclinal axis 

strikes a little east of north, passing about 500 feet east of 

summit 6518. Dips on the east limb are in general steeper than 

those on the limb common to both the syncline and the anticline. 

~.-
GEOLOGIC STRUCTURE 85 

The anticlinal axis strikes nearly north, through a point 1,000 

feet east of summit 6230. On the north the axis appears to 

split into several minor folds, one of which is shown in plate 7, B. 

On this fold the steeper dips are on the west limb, where locally 

vertical beds are found. West of the anticline the folding 

apparently increased in intensity but decreased in regularity, 

and no continuous folds could be recognized in the low hills 

that form the northwest spur of Dutch Mountain (sec. F-F'). 

In the minor and discontinuous folds in this region overturned 

beds are locally found. Figure 10 shows the course of a crossbedded dolomitic sandstone west of the anticlinal axis which 

illustrates these points. The position of three summits shown 

on the topographic map is added to aid in the location of the bed. 

It is probable that two stages of folding are represented west 

of the Trail Gulch fault. The two larger and more persistent 

folds are believed to have been formed before the Trail Gulch 

fault became active, as they do not affect the fault and there 

are no comparable folds east of the fault. The smaller, locally 

overturned folds to the north, however, are considered to have 

\ 

\ 

N 

.5552 

r 

• 15230 

FIGURE 10.-Sketch m!lp showing folding of a bed In the Oquirrh formation on 

the northwest side of Dutch Mountain. Elevations ere summits shown on 

plate 2. 

been superposed on the older folds at the time of the reverse 

movement along the Trail Gulch fault. The steep dips on the 

east limb of the larger syncline may also have originated at 

this time, as in the rest of the folded belt the intensity of folding 

increases westward. . 

Fault along west 8ide of Dutch Mountain.-The notably 

straight west side of Dutch Mountain, which transgresses the 

structure at a considerable angle, suggests strongly that there 

has been relatively recent faulting here. Locally the tips of the 

spurs along this line exhibit slickensided surfaces. The throw 

along the supposed fault cannot be determined stratigraphically, but there is a difference in altitude of about 500 feet 

between the linear flat ridges east of the (ault and the flattopped isolated outcrops to the west. To the south the fault 

line changes its strike from southeast to east-southeast. The 

topographic discordance persists into this region, but to a 

somewhat less degree. Rock exposures on both sides of the 

fault, however, show that the movement along this part of it 

has been more complex. 

at t.h~ Qq.uinb. {otuUl.tion on both sides of the fault and the 

The distribution of the central facies 

__......tMnOl1ibeut llide 

, ThfI eonfiicting evidence • beUeYed to JDdlcate that movement along the fault has 

occurred at two different times-an earlier one, in which the 

movement was probably transverse, resulting in the relative 

depression of the thrust northeast of the fault, and a recent one, 

in which the apparent movement was in the opposite direction 

but was not of sufficient magnitude to conceal the older movement. 

Mutual relations of the structural features.-The relations of 

the structural features exposed in the Dutch Mountain block 

to one another are not as clear as in the blocks to the south. 

A group of north-south normal faults on the east side of Dutch 

Mountain appear to be the oldest features that were recognized. 

They are cut by a series of northwesterly normal faults, the 

greater part of whose activity must have preceded the Ochre 

Mountain thrust, and for this reason they are considered 

to have been formed in the second stage of the first cycle. 

None of these faults were found in contact with structural 

features assigned to the first stage of the second cycle, however, 

and their age is therefore in some doubt. 

The initial stage of the second cycle is clearly represented by 

the Dutch Mountain thrust, whose age relative to the Ochre 

Mountain thrust is definitely shown by the intersections of the 

two thrusts with the Trail Gulch fault. This stage appears 

to have been characterized chiefly by folding, however, and at 

least five of the larger folds in the block were formed at this time. 

Normal faults of the second stage of the cycle are abundant. 

The bulk of the movement along the Trail Gulch and Spotted 

Fawn faults was accomplished before the development of the 

Ochre Mountain thrust, and several parallel faults of less 

magnitude are of the same age. 

The dominant structural feature of the block-the Ochre 

Mountain thrust-was formed in the first stage of the third 

cycle. The relatively thin thrust plates beneath it north of the 

Spotted Fawn mine are contemporaneous. A number of transverse faults, of which the PoolCanyon fault is the largest, appear 

to be only slightly older than the Ochre Mountain thrust and to 

be of the same age as the North Pass thrust. Renewed activity 

along the Trail Gulch fault and minor drag folding adjacent to 

the fault also occurred at this time. Normal faulting in the 

second stage of the third cycle appears to have been very slight 

in amount, only one fault being assigned to this stage . 

The fourth cycle was marked by the formation of the Garrison 

Monster transverse fault and its associated warping and conjugate faulting. Several of the northwesterly conjugate faults 

appear to have followed normal faults that first became active 

in the second cycle. 

The youngest faults are the relatively recent normal faults 

to which the elevation of the block is largely due. The two 

faults of this age on the west have utilized older fault lines along 

at least parts of their courses. 

NORTHWESTERN BLOCK 

The northwestern block is west of the Dutch Mountain block 

and northwest of the Ochre Mountain block. Its southern 

boundary is the northern limit of the wide part of the Deep 

Creek Valley. The boundary between this block and the Dutch 

Mountain block coincides with a normal fault of rather large 

throw. There is, however, no structural break between this 

block and the Ochre Mountain block. 

Geologically, the block is one of the simplest so far considered. 

The dominant structural feature in its east half is a recumbent 

anticline, whose ads appears to lie roughly parallel to and 2,500 

to 3,000 feet higher than the Ochre Mountain thrust (secs. F"-F, 

D"-D, and N"-N). The fold is older than the White Sage 

formation, but both are cut by two groups of faults, one striking 

northeast and one northwest. 

The portion of the block west of Bar Creek is separated from 

the eastern portion by a nearly north-south zone, which is to 

the north a gravel-filled valley, and to the south a linear outcrop 

of volcanic rocks. This zone marks the line of a fault or group 
86 GOLD HILL MINING DISTRICT. UTAH 

of faults along which the beds to the west have probably been 

dropped 5,000 feet. There is some evidence to indicate that a 

small part of this throw may have occurred in rather recent 

time. The region west of the fault zone is characterized by an 

open anticlinal fold and abundant small normal faults. Along 

the extreme west edge, however, there are locally rather close 

folds and minor overthrusts. 

Tank lVashfauU.-The fault along the boundary between the 

northwestern block and the Dutch Mountain block is nowhere 

exposed, but one is obviously required in Tank Wash between 

the eastward-dipping White Sage formation at an altitude of 

5,610 feet and the fossiliferous beds high in the Oquirrh formation near benchmark 5544, on the one hand, and the beds low 

in the Oquirrh formation to the east, on the other. The total 

throw along the fault in this region must amount to '1bout 4,000 

feet, which was probably accomplished in stages, as indicated 

by the relations of the fault to the Ochre Mountain thrust. 

To the north the strike of the fault appears to swing to the 

northwest, as is suggested by the fracturing seen in the exposures 

at the road fork southwest of benchmark 5068 on the Ferber 

Road. A fault with similar strike and westward dip in the 

Ochre Mountain block (pp. 76-77) is thought to be a continuation 

of the Tank Wash fault. This fault is clearly later than the 

overthrust and has a throw estimated at 300 feet. In both of 

these respects it differs from the northerly outcrops of the Tank 

Wash fault. The large throw along the 

fault is clearly of pre-thrust age, as the 

nearly continuous exposures south of Dutch. 

Mountain show that the thrust has nowhere 

been cut by normal faults that cause more 

than a few hundred feet of vertical displacement. The main movement along 

the Tank Wash fault must therefore have 

occurred before the development of the 

Ochre Mountain thrust, and the postthrust throw of 300 feet represents renewed 

movement along the older fault. 

Twin Peaks recumbent anticline.-The 

recumbent anticline that is so prominent 

a feature of the east half of the block is 

best exposed just south of the southern 

summit of Twin Peaks. Exposures OIl 

the south side of peak 6147, 4 miles to 

the south, are also convincing and serve 

to justify the extension of the axis of the 

fold between the two points into regions 

where it can be located less easily. As 

FIGURE H.-Generallzed section showing supposed original relations between the Twin Peaks recumbent 

anticline Rnd the Dutch Mountain thrust. The areas enclosed by dashed lines represent in a general 

way the present exposures on both sides of the two normal faults. 

shown on the map and structure sections DJI-D, P"-[<', and 

N"-N, the axial plane of the fold has a low and somewhat 

irregular northerly dip. At both Twin Peaks and peak 6147 

the beds involved in the fold are the massive rather pure limestones that belong in the lower part of the western facies of the 

Oquirrh formation. This indicates that the original strike of 

the axis of the fold was about N. 15° E. The present low northward dip of the axial plane is probably a later development. 

The fold is clearly older than the Eocene (1) White Sage formation, for beds belonging to that formation overlap the axis of the 

fold about a mile west of a point in Tank Wash on the Ferber 

Road at an altitude of 5,610 feet. It is also, of course, older than 

the northeasterly and northwesterly faults that cut that formation. It is believed to be older than the Ochre Mountain thrust 

for. the following reasons: The fold is clearly older than the 

latest movement along the Tank Wash fault, along which the 

bulk of the throw must be of pre-thrust age, although some 300 

feet may represent post-thrust movement. It is also probably 

older than the pre-thrust component of the normal fault. If 

it were younger, some trace of the fold should appear on the 

high ridges on Dutcli Mountain west of the Trail Gulch fault, 

but none has been found. Moreover, if the fold were younger 

than the earliest movement along the fault, the fault could 

scarcely have the linear outcrop it now shows, nor could there 

have been renewed movement along it. If these two features 

can be relied upon, the fold must be considerably older than 

the Ochre Mountain thrust, and the folding must have been 

separated from the thrusting by a period of normal faulting. 

Relations oj recumbent anticline to structural jeatures on Dutch. 

Mountain.-The Dutch Mountain thrust and the larger folds 

west of the Trail Gulch fault on Dutch Mountain, like the 

Twin Peaks recumbent anticline, are older than the Ochre 

Mountain thrust. These features are also older than two westward-dipping normal faults of rather large throw, and it is 

-believed that they were all formed during the same cycle of 

deformation. If this view is correct, the more easterly exposures 

represent the features formed at greater depths, for the two 

younger normal faults, the Trail Gulch fault and the Tank 

Wash fault, have the down-thrown side on the west. The most 

intensive folding, however, is found in the westerly exposures, 

where the recumbent anticline occurs. Folding in the Oquirrh 

formation west of the Trail Gulch fault decreased in intensity 

eastward, and east of the fault folds are essentially absent. 

The strongest folding, therefore, was originally at the higher 

altitudes. Figure 11 shows the supposed relations between these 

E; 

~r---------------------____-' 

I _I l ~ 

------------~~~~--~~ Dutch _ tAountain thrust I I ::z !~ i t 

Ap.Rroximate position .I. - L I 

of Tank Wash fault Appro~ima~p;;;rt~n---= 

of Trail Gulch fault 

_ 

__________________________ 

features before the initiation of movement along the Trail Gulch 

and Tank Wash faults. 

The concentration of the close folding at higher altitudes 

suggests that a thrust fault, now removed by erosion, once 

existed above the highest of the present exposures. The observed structure and stratigraphy west of Bar Creek (p. 88) to 

some extent support this view. 

The close folds of relatively small scale and the variations in 

the thickness of individual beds that are thought to lie immediately below the main recumbent ford (fig. 11) appear to be 

rather poorly exposed in the vicinity of hill 5850, west of benchmark 5544, and in the region south and west of the hill toward 

summit 6266. 

Minor jaulting east oj Bar Creek.-Four faults of relatively 

small throw cut the recumbent fold and also the White Sage 

formation. Two of these faults strike northwest and ~re offset 

by two northeasterly faults. One of the northwesterly faults 

is readily recognized on the southwest side of Twin Peaks, 

where the anticlinal axis is dropped on the southwest side. 

The vertical throw amounts to about 800 feet and may be 
GEOLOGIC STRUCTURE 87 

measured rather accurately by the offset shown by the upper 

contact of the series of limestones that form Twin Peaks. Just 

north of peak 5876 this fault is offsct about a quarter of a mile 

to the east by a northeasterly fault. South of this point the 

offset segment is readily traced by reason of the fact that it 

limits on the east a narrow outcrop of the White Sage formation. 

Still farther to the south the fault is concealed by volcanic rocks. 

The second of the two northwesterly faults crops out northeast of the 5,850-foot hill that lies on the north flank of peak 

6266. This fault forms the western boundary of another 

exposure of the White Sage formation. The positions of the 

axial plane of the fold On both sides of the fault indicate that 

the maximum thro;!'v along it does not exceed 40'0 feet. The 

fault is terminated on the south by one of the northeasterly 

faults. The offset portion was not recognized in the lava-capped 

region to the south. 

The northeasterly fault south of Twin Peaks can be definitely 

recognized only on the north side of peak 5876, where it offsets 

the northwesterly fault. The throw of the fault must be rather 

large at this point, with downthrow to the southeast, because 

of the stratigraphic differences on the two sides and also because of the amount of offset of the older fault. The displacement must die out within a short distance to the southwest, 

however, for individual beds that cross its projected strike less 

than a mile southwest of peak 5876 show no offset. The relation 

of the fault to the northwesterly fault along the east boundary 

of the block is unknown, the gravel cover in this region preventing any direct observations. 

The second of the two northeasterly faults is on the north 

and northwest sides of peak 6266, where its presence is indicated 

by the difference in structure on the two sides. To the northwest the axial plane of the fold crops out at an altitude of about 

5,700 feet, arid to the southeast the structure observed at the 

summit of hill 6266 shows that the axial plane must have been 

several hundred feet higher still. The throw along the fault at 

this point must therefore approach 1,000 feet. To the northeast the course of the fault is apparently marked by a region of 

silicification east of hill 5850. Beyond this point the fault was 

not recognized, and the fact that individual beds continue 

unbroken across its projected strike seems to indicate that it 

dies out within a rather short distance in this direction. 

The age of these four faults is not known. On plate 3 they 

are all assigned to the fourth cycle, as they correspond in strike 

with the conjugate faults related to the Garrison Monster 

transverse fault. The apparent throws are somewhat larger 

than those along the other conjugate faults, and the faults may 

therefore represent two unrelated stages of faulting, the northwesterly faults being the older. 

Bar Creek fault.-West of peak 6147 there is a strip of volcanic rocks about three-quarters of a mile in width. This is 

succeeded northward by a somewhat wider valley filled with 

gravel. The gravel and volcanic rocks in this belt must conceal 

a considerable fault or fault zone, because of the differences in 

structure and stratigraphy on the two sides. On peak 6147, 

where prevolcanic rocks crop out nearest to the supposed fault, 

here called the Bar Creek fault, the rocks belong to the thick 

limestone member that occurs near the base of the western facies 

of the Oquirrh formation. At this point, too, the axial plane of 

the recumbent fold is exposed at an altitude of about 5,600 feet. 

West of the concealed zone, however, the beds belong to the 

highest portion of the Oquirrh formation and are overlain by 

the White Sage formation. Furthermore, the structure observed on the west side cannot be correlated with the recumbent 

fold, although the altitudes are such that the axis of this fold 

should be exposed if it continued westward unbroken. These 

two features make it seem certain that the belt is the site of 

notable displacement with north-south strike and with downthrow to the west. The apparent throw along the fault is 

about 5,000 feet, as it includes the thickness of the Oquirrh 

formation above the limcstone member (4,500 feet) plus about 

500 feet of that member. If, however, the region west of the 

fault is underlain by a thrust fault, as there is some reason to 

believe (p. 88), the actual throw may depart widely from this 

estimate. The present distribution of the White Sage formation 

on both sides of the fault is such that a much smaller throw is 

necessary than any that would reasonably explain the structure 

shown by the underlying Carboniferous rocks and suggests that 

the Bar Creek fault, like many others in the quadrangle, has 

been the site of recurrent movement. A rough measure of the 

later movement is suggested by the difference in altitude of the 

old postmature erosion surface on the two sides of the fault, 

which amounts to about 600 to 800 feet, the region west of the 

fault being the lower. This figure is ample to explain the present distribution of the White Sage formation if it was, as 

supposed, deposited in relatively small basins. 

Anticline west of Bar Creek.-West of the Bar Creek fault 

the Carboniferous formations are folded in a poorly defined 

anticline, which is most readily recognized to the south. About 

a mile east of that portion of Deep Creek between benchmarks 

5097 and 5045 the Oquirrh formation strikes west of north and 

dips to the east. Farther north and west the strike swings to 

the northwest. On the west side of Deep Creek the strike is 

somewhat more westerly, and still farther west it changes to 

west with northerly dips. Finally, the most westerly outcrops 

of the Carboniferous formations strike a little east of north and 

dip to the west, completing the fold (sec. D"-D). 

The axis of the fold in this region strikes about N. 150 E. 

through benchmark 5045 and plunges gently to the north. 

North of the hills west of the 5,122-foot depression the projected 

axis passes beneath gravel and could not be further traced. At 

this point the axis is poorly defined and is obscured by faulting. 

Several minor folds and thrusts exposed near the northern 

boundary of the quadrangle may replace the single major fold 

to the north. 

MinOT folds west of Bar Creek.-The most striking of the 

several minor folds west of Bar Creek is an anticline with moderately steep dips on both limbs, which is exposed in the isolated 

hill in the Deep Creek Valley half a mile east of north of altitude 

4,992 feet on the Deep Creek road. Just beyond the northern 

border of the quadrangle dips as high as 850 were observed. 

A syncline must be present in the alluvium-filled valley between 

these outcrops and the hills to the east. 

Southeast of the anticline the erratic east and southeast dips 

north of hill 5434 may indicate the presence of another subsidiary fold on the west limb of the main anticline, but the 

extensive faulting in this region prevents any satisfactory interpretation. 

Two small overturned folds are exposed beneath a minor 

thrust fault in the hills along the western border of the quadrangle west and northwest of altitude 4,984 feet on the Deep 

Creek road. The presence of the folds is shown by the repetition of outcrops of the dark cherty beds in the upper portion 

of the Oquirrh formation, which dips 600 -75° W. on both limbs 

of the folds. The more westerly of the two folds is an anticline. 

It is cut off on the south by a fault striking north of west, which 

just east of the quadrangle boundary swings in strike to nearly 

south and decreases notably in dip. The unfolded beds above 

the fault dip rather gently to the south and include the basal 

beds of the Gerster formation. The stratigraphic hiatus between this hori:aon and the black chert zone is about 2,500 feet. 

The curving fault seems to be best explained as a transverse 

fault that passes eastward into a thrust, a relation that w:as also 

found in several places in the Deep Creek Mountains (p. 67). 

Although these faults are shown on plate 3 as being of the same 

age as the large anticline, it is equally possible that they were 

formed in a later structural cycle. 

There is apparently another fold on the west side of Deep 

Creek. This is an east-west synclinal warp that is indicated 
88 GOLD HILL MINING DISTRICT, UTAH 

by the northerly dips in the hills west of altitude 5,045 feet and 

southerly dips in the region west of altitude 4,984 feet. The 

intervening low-lying area is covered by volcanic rocks and 

gravel, which conceal the structure of the Carboniferous rocks 

beneath them. The syncline cannot be recognized on the east 

side of Deep Creek. The strike of the axis of this fold does 

not correspond to any of the other structural features that have 

been found in the district, and the apparent limitation of the 

fold to the west side of Deep Creek suggests that it may be 

causally connected with the volcanic rocks that now occupy 

its axial portion. Two intrusive plugs were found in this volcanic area, and a careful search might disclose others. The 

syncline might therefore be interpreted as a downwarp resulting from the extrusion of volcanic matter from a source immediately beneath. 

Faulting west of Bar Creek.-Three groups of faults are found 

in the region. A group of northeasterly faults appear to be 

the youngest of the three and are widely distributed. A group 

of northwesterly faults are also found throughout this part of 

the block; they are everywhere cut by the northeasterly faults. 

Two nearly north-south faults northwest of altitude 5,062 feet 

on the Deep Creek road are thought to belong to a third group. 

They are terminated on the south by one of the northwesterly 

faults. 

Two of the northwesterly faults and one northeasterly fault 

have rather large throws. The northeasterly fault cuts the 

northwesterly faults and is believed to shift them three-quarters 

of a mile, the offset being to the northeast on the northwest 

side of the younger fault. 

The two northwesterly faults are both exposed on the east 

side of Deep Creek. The more southwesterly one crops out 

east of benchmark 5097 and has brought the White Sage formation on the southwest into contact with the Oquirrh formation 

on the northeast. By projecting the contact between the two 

formations as exposed on both sides of the fault, the throw is 

seen to be about 1,200 feet. The more northeasterly of the 

two faults is parallel in strike and about three-quarters of a mile 

distant. The relations are similar, but the throw is about 

1,800 feet. 

On the west side of Deep Creek northwesterly faults with 

comparable throws are found some distance to the north. Thus 

just west of benchmark 5062 on the Deep Creek road there is a 

northwesterly fault whose throw is about 1,000 feet and which 

appears to correspond with the more southwesterly of the two 

faults east of the creek. The second northwesterly fault appears 

to be concealed by the gravel north of altitude 5,045 feet on the 

Deep Creek road. The throw along this fault is about 2,000 

feet, as measured by exposures of the White Sage formation on 

each side of the fault, and it is therefore comparable to the 

throw along the more northeasterly of the two faults east of 

Deep Creek. 

The northeasterly fault that is believed to have caused this 

shifting of the northwesterly faults is concealed by the gravel 

and clay that floor the Deep Creek Valley throughout most of 

its course. The exposures on the east side of Deep Creek, east 

of altitude 5,045 feet, permit it to be located rather closely, 

however, as beds in the White Sage formation southeast of the 

fault strike directly into beds well below the top of the Oquirrh 

formation on the northwest. The throw along this fault appears 

to be chiefly horizontal and to amount to about three-quarters 

of a mile. The vertical component of the throw is comparatively small and varies not only in amount but in direction at 

different places along the fault. 

All three faults are shown on plate 3 as having been formed 

in the fourth structural cycle, in the belief that they are a part 

of the conjugate fault system exhibited on Dutch Mountain. 

The throws along these faults are much larger than were observed on Dutch Mountain, however, and these faults may 

therefore be of different age. 

Concealed thrust fault west of Bar Creek.-If, as seems certain, 

the down-faulted continuation of the Twin Peaks recumbent 

anticline underlies the region west of the Bar Creek fault, any 

attempt to project the surface structure downward to connect 

with that fold fails, because of the impossibility of correlating 

the progressively older beds encountered in the core of the fold 

as it is followed westward with the progressively younger formations exposed at the surface westward from the Bar Creek 

fault. The only apparent method by which these conflicting 

features may be reeonciled lies in the assumption that a nearly 

horizontal thrust fault must intervene between the recumbent 

fold and the structural features exposed at the surface. East 

of the Bar Creek fault this hypothetical thrust has been removed 

by erosion, but it provides an explanation of the curious relation 

of the recumbent anticline to the observed structure on Dutch 

Mountain. 

Mutual relations of the structural features.-The faults and 

folds in the northwestern block are not easily dated with relation 

to those in the remainder of the quadrangle. The folding of the 

Twin Peaks recumbent anticline and the major part of the 

movement along the Tank Wash fault are the only two events 

whose chronologic position is certain, and both belong in the 

second structural cycle. The early movement along the Bar 

Creek fault is also thought to have occurred during this cycle, 

as all the other normal faults of large throw found in the quadrangle were formed at that time. If that assignment is correct, 

the large anticline west of the fault was also formed at least as 

early as the second cycle, for it is cut by the fault. The minor 

folds and thrusts associated with the anticline were perhaps also 

formed at this time, but it is equally possible that they were 

developed at some later date. 

The third structural cycle, which produced so many changes 

in other parts of the quadrangle, is very poorly represented in 

this block. The warping of the axial plane of the recumbent 

anticline may have occurred at this time, as may some of the 

minor folds and thrusts shown on plate 3 as belonging to the 

second cycle. The north-south normal faults west of Deep 

Creek are believed to represent the second stage of the third 

cycle. 

The abundant northeasterly and northwesterly faults found 

throughout the block have been assigned to the fourth cycle, 

in the belief that they are similar to the conjugate faults of 

this age on Dutch Mountain. 

The recent movement along the Bar Creek fault and the eastwest synclinal warping west of Deep Creek are the latest events 

recognized. 

QUARTZ MONZONITE BLOCK 

The quartz monzonite block differs from the other structural 

blocks in the quadrangle in that the faults it contains either 

affect only the quartz monzonite or have a causal relation to 

the quartz monzonite. Three groups of faults appear to be 

included by this description. The first group is composed of 

faults that are thought to have formed contemporaneously with 

the emplacement of the intrusive; the second is made up of 

faults of small throw and diverse age that probably are related 

to the cooling igneous mass; and the third includes faults that 

seem to require the action of external forces for their formation. 

Faults related to the emplacement of the quartz monzonite.-The 

faults of the first group cannot be proved to be directly connected with the intrusion, for they do not themselves cut the 

quartz monzonite. The faults that are placed in this group are 

those that displace the Ochre Mount.ain thrust in the roof 

pendants, or in the sedimentary rocks adjoining the stock 

along or near its western boundary. The location and character 

of the two largest faults in this group are described on pages 

75-76, where these faults are correlated with the intrusion on 

the grounds that elsewhere in the district faults of this magnitude did not cut the thrust. 

-

GEOLOGIC STRUCTURE 89 

The distribution of these faults seems to have some significance. They show a localization along the western border of 

the stock, to which they are roughly parallel. Similar faults 

appear to be absent both in the roof pendants to the east and 

in the exposures of sedimentary rocks along the southern and 

northern borders. These spatial relations are the same as 

those of a group of ore deposits that contain considerable 

quantities of such minerals as tourmaline, humite, axinite, 

danburite, and scheelite, the formation of which is commonly 

thought to require relatively high temperatures. 

The coincidence of the belt of faulting with the belt of hightemperature mineralization is thought to indicate that this 

belt marks the location of the primary channel through which 

the quartz monzonite was intruded, the faulting being a secondary consequence of the upwelling magma. As the faulting 

ooourred before the intrusive solidified and the faults were 

utilized by the magma in its asoent, there would be no displacement of the igneous oontaots, and thus there is no direct 

evidence of the relation between the two. 

In several other places the quartz monzonite has used faults 

during its emplacement, but in all of them, so far as can be 

ascertained, the relation is a passive one, the faults being muoh 

older than the intrusive and undergoing no renewal of movement 

during the process. This is certainly the case on the south side 

of Montezuma Peak, where the influence of earlier faulting 

upon the boundaries of the igneous rock is most marked; and 

also in Pool Canyon, where the older Pool Canyon transverse 

fault has served to localize a tongue of the intrusion. 

There is a considerable body of evidence indicating that the 

intrusive did not exert any doming effect on the invaded rooks 

except for the relatively slight uplift in the zone described in 

the preceding paragraphs. This is best shown by the exposure 

of the Ochre Mountain thrust plane in roof pendants at altitudes rather closely concordant with those of the thrust in 

areas distant from the intrusion. On the southern slopes of 

Montezuma Peak, moreover, the intrusion has broken through 

an eastward-dipping monoclinalsequence without any apparent 

effect on the preintrusive strike and dip of the invaded rocks. 

The same lack of concordance between the boundary of the 

intrusive and the structure of the invaded rocks is shown along 

the northern and western contacts but somewhat less olearly 

because of the more complex structure of the sedimentary rocks 

at these places. 

Structural features related to the solidification of the quartz 

monzonite.-The struotural features of the seoond group are 

numerous and wide-spread. They include faults and shear 

zones whose throws can be definitely measured, as well as fractures followed by dikes and veins, along some of which also 

faulting can be definitely proved. The joints that occur in 

the quartz monzonite may also be included, for the evidenoe is 

olear that at least some of them were formed during the same 

period as the other structural features of this group. 

An attempt was made to classify these features according to 

their strikes and dips and to correlate such groups either with 

an areal distribution or with the type of dike or vein that filled 

them or was faulted 'by them-an indirect and approximate 

measure of the age. In this attempt nearly 100 strikes and dips 

were chosen at random, about one half from quartz-sulphide 

veins and the remainder from other ore-bearing veins, from 

dikes, and from unmineralized faults. 

The only conclusion that was reached from this study was that 

unmineralized faults or shear zones showed a strong tendency 

to strike either nearly east or nearly north. For the other 

groups there was no uniformity in strike or dip within a group, 

nor was any pronounced areal pattern of fracturing discernible. 

A graphic compilation of the strikes and dips upon which this 

conclusion is based is shown in figure 12. 

These fractures appear to be of diverse age and throw, as 

well as of diverse orientation, although they were all formed after 

3fi311-3&--7 

the solidification of the quartz monzonite and before the introduction of the material that now fills them. Only a few preserve any evidence whatever of the amount of movement along 

,them. 

Intersecting dikes of different kinds within the stock indicate 

fissuring at different times. They are found particularly northwest of Gold Hill, and also immediately east of hill 5675, on 

the north side of Rodenhouse Wash. There appears to have 

been little or no movement along any of these fractures. 

The relatively early formation of some of the joints in the 

igneous rock is shown by two different sets of phenomena. 

One is the coating of joints by blaok tourmaline or green epidote, 

both minerals characteristic of what are thought to be the earliest of the ore deposits. The other is the transgression of the 

joints at a large angle by quartz-sulphide veins on the old Mammoth claim and also at several prospects on the south side of 

Rodenhouse Wash. 

Less conclusive evidence for different times of fracturing is 

furnished by compound dikes and by the occurrence in the same 

fracture either of two different kinds of veins or of a dike and a 

vein. Compound dikes are not uncommon, and in the Monocca 

mine a carbonate vein follows the same fissure that had been 

filled earlier by a copper-lead sulphide deposit. The presenoe 

of a quartz-sulphide vein along the wall of a granite porphyry 

dike in the Cyclone mine proves that this partioular fracture 

must have been opened at two widely separated times, for quartzsulphide veins were formed relatively late in the sequence of 

mineralization, all of which took plaoe later than the intrusion 

of the dike. 

There are only a few fractures along which the throw can be 

determined. One of these is exposed on the property of the 

Silver & Gold Mining Co., southeast of Calico Hill. Here an 

unbrecciated quartz vein occupies a fissure that displaces the 

contact of the quartz monzonite and the sedimentary rocks 10 

feet. An even more striking example is shown on the Helmet 

claim of the Western Utah Extension Copper Co., where a 

mineralized fissure striking north cuts an augite porphyry dike 

striking east of north and displaces it about 50 feet. The individual mine descriptions include additional information on this 

group of fractUres. 

The differences shown by these fractures in strike and dip, 

and in age, seem rather definitely to eliminate any directed horizontal force as being instrumental in their formation. As they 

are essentially limited to the intrusive, they have evidently resulted from the stresses set up at intervals in the slOWly cooling 

stock. 

Structural features not related to the emplacement or cooling of 

the quartz monzonite.-In addition to the structural features of 

the two groups just described, there appears to be some evidence 

for faulting that requires a cause outside of the stock itself. 

One of the most significant pieces of evidence in this respect was 

observed in a tunnel on the northeast side of Ochre Mountain, 

which cuts the crushed rocks immediately beneath the Ochre 

Mountain thrust. East of the tunnel an uncrushed dike of 

quartz monzonite porphyry is exposed outting the overridden • 

rocks. The dike is about a mile west of the stock--clearly 

well beyond the range of any movements emanating from the 

igneous rocks. What is apparently a continuation of the dike 

in the tunnel, however, is thoroughly orushed, apparently as 

the result of movement along the major thrust. As several 

of the roof pendants included within the quartz monzonite 

show that the Ochre Mountain thrust is older than the intrusion, 

the crushed dike in the tunnel can only be interpreted to mean 

that there has been renewed movement along the thrust after 

the emplacement of the stock and beyond its range of influence. 

EvIdence to the same effect appears to be 1lofforded by the 

intersecting dikes east of hill 5675, on the north side of Rodenhouse Wash. At the summit of the hill and extending westward 

are several quartz and quartz-carbonate veins that dip at a 
90 GOLD HILL MINING DISTRICT. UTAH 

rather low angle to the" west and are exposed at intervals for 

more than 2 miles to the south. One of the dikes on the east 

side of the hill strikes south of east, almost normal to the strike 

of the veins. The other dike, a composite one, strikes south of 

east and is clearly the younger, as it can be traced continuously 

through the first. It has, however, been sheared sufficiently to 

develop a rude cleavage, a feature that is lacking in the older 

dike. Both dikes are cut off by the most easterly quartzcarbonate vein. West of the zone of veins the quartz monzonite 

has been thoroughly chloritized and is seamed by a network of 

thin quartz veinlets. 

evidence of compression movements. Among the most notable 

are two faults exposed a short distance south of the Western 

Utah Copper Co.'s open cut on Gold Hill. Both strike about 

N. 20° E., and one at least definitely dips to the west. The 

more westerly of the two cuts the vein on the Helmet claim of 

the Western Utah Extension Copper Co. in such a way that it 

must either be a reverse fault or a normal fault in which the 

horizontal component of movement is large. The dip on the 

eastern fault was not observed, but its relations to the westwarddipping porphyry dike that extends southward from the summit 

of Gold Hill are the same. Although neither of these faults can 

~N. ----,.. 

IO__~r-~r-~r-__/Oo 

w. 90,>--/--t­

<XI 

<::)

• 

FIGURE 12.-Strikes and dips of various types of fractures in the quartz monzonite. Fractures having dips with an ea8terly component shown at the right, those with a 

westerly component at the left. Strike direction measured along the circum(erence o( the circle; amount of dip measured hy distance outward from center of circle. 

These observations, particularly the selective shearing shown 

by the dikes, suggest that the zone now occupied by the veins 

represents a zone of faulting that resulted from compression. 

The faulting must have occurred after the intrusion of the 

dikes on the east side of hill 5675 and before the formation of 

the quartz and quartz-carbonate veins. 

With the evidence from these two localities in mind, other 

phenomena observed in the intrusive area appear to present 

be definitely said to be a reverse fault, their parallelism in 

strike with the zone to the south would seem to make this the 

most probable explanation. 

Similarly, the fact that all the veins in the district with a 

nearly north-south strike show gouge, in which crushed ore 

minerals are present, on either or both walls, although veins with 

a nearly east-west strike do not, is also suggestive of a directed 

pressure. It is also possible that the numerous small faults of 
IGNEOUS METAMORPHISM 91 

east-west strike and nearly vertical dip that cut both veins 

(as on the Copper Queen Midland group) and dikes (as best 

shown east of the Success workings) may be considered to 

represent small transverse faults that accompanied the reverse 

faulting. 

The normal faults that form the boundaries between sedimentary and igneous rock east of the U.S. mine (p. 76) and 

the Western Utah mine (p. 77) may represent a stage of 

normal faulting that fonowed the reverse faulting. Both the 

normal and reverse faults at the U.S. mine are clearly later 

than the ore. The throws along the normal faults-2DD to 300 

feet at the U.S. mine and probably an equal amount or more 

at the Western Utah mine-are much larger than any deterJnined for the faults belonging to the second group, and this, 

with their postmineral age, makes it difficult to consider that 

they have formed as a result of the cooling of the intrusion. 

IGNEOUS METAMORPHISM 

Throughout the greater part of the quadrangle the 

quartz monzonite stock and the sedimentary rocks 

which it invades have changed in composition or 

texture in varying degrees as a result of the after effects 

of the intrusion. In part these changes may be 

correlated with differences in the original composition 

of the rocks affected, but for the greater part they 

are clearly the result of the addition of material to 

the rock. In both igneous and sedimentary rocks a 

single rock type may have several different altered 

facies, each of which is characterized by some distinct 

mineral or group of minerals. In many places rocks 

containing minerals of different groups were found, 

but microscopic study of such occurrences indicated 

that different groups were not contemporaneous but 

that one set replaced or was replaced by another. 

. Recognition of a series of such progressive replacements 

in both the altered sedimentary rocks and the igneous 

rocks led to the conclusion that the processes causing 

the alteration extended over a considerable time, during which they were continuously changing. 

Ores of gold, silver, copper, lead, zinc, arsenic, 

tungsten, bismuth, and molybdenum are also widely 

distributed throughout the quartz monzonite area 

and in the bordering sediments. These are associated 

with the metamorphosed rocks mentioned in the preceding paragraph, and in many of the occurrences it 

is apparent that some, if not all, of the ore minerals 

closely approximate in age certain of the mineral 

groups that characterize the igneous metamorphism. 

There thus appears to exist a parallelism between the 

progress of the rock alteration and the formation of 

the ore minerals. Additional factors, however, prevent 

a close correlation between the distribution of a particular facies of rock alteration and the ore bodies, 

which are the result of concentrations of ore minerals. 

Perhapi:l the most effective of these factors is the 

presence of crustal movements during the time interval 

in which the alteration and ore deposition took place. 

In localities where no crustal movement has occurred 

the correlation is possible. There is some evidence to 

indicate that in this region fracturing and minor faulting proceeded hand in hand with the processes of 

alteration and to this may perhaps be attributed the 

numerous but disappointingly small concentrations of 

ore minerals in the district. 

ALTERATION OF THE SEDIMENTARY ROCKS 

The metamorphism of the sedimentary rocks as considered here is of four classes-recrystallization, alterations resulting in the formation of silicate minerals, 

alteration to jasperoids, and dolomitization. This 

grouping is in some respects unsatisfactory, for it does 

not permit separate consideration for the effect of the 

original composition of the rock. It lends itself more 

readily to a comparison with the changes undergone 

by the quartz monzonite, however, and has been 

adopted for this reason. Moreover, the greater part 

of the rock affected is made up of limestone. 

Recryslallization.-The most widely distributed type 

of alteration within the quadrangle is recrystallization, 

and the greater part of the metamorphosed area shown 

on plate 2 is underlain by rocks that have been recrystallized rather than changed by the introduction of 

additional material. This appears to have been the 

earliest of the several types of metamorphism, for 

minerals characteristic of the other types have been 

found replacing all varieties of the recrystallized sediments. The distribution of the recrystallized rocks 

and especially the failure to find much evidence of 

alteration of this kind in some of the masses of Ochre 

Mountain limestone occurring as roof pendants within 

the quartz monzonite area appear to require somecausative agency in addition to the heat given off by 

the intrusive rock. The fact that the essentially unaffected limestones lie above the Ochre Mountain thrust 

and are separated by it from highly altered sediments 

beneath would seem to supPJrt the theory that the 

recrystallization was induced by circulating waters, 

either connate or magmatic, that had been started in 

motion by the magma. 

Both limestones and quartzites affected by the recrystallization show an increased gra.in size, which was 

accompanied by the development of an allotriomorphic 

texture and a marked bleaching. In addition, the 

strain phenomena found in both the unaltered calcite 

and the quartz have disappeared. In the rocks made 

up of calcite and quartz there appears to have been 

practically no reaction between these two minerals 

during the period of recrystallization. For example, 

in specimens of strikingly recrystallized limestone from 

the Western Utah Copper Co.'s Gold Hill mine no 

silicate minerals were noted, although solution of the 

rock in dilute acid showed the presence of a small 

percentage of quartz. 

This feature does not seem to be true for the argil~ 

laceous rocks, of which the black shales of the Manning 

Canyon formation are the most abundant examples. 

These rocks have been altered to andalusite hornfels, 

in which biotite and sericite have been formed in 
92 GOLD HILL MINING DISTRICT, UTAH 

abundance, in addition to the andalusite. The several stages in the development of the andalusite, which 

have been illustrated and described by Kemp,2O may 

be observed in a single thin section and, to the writer, 

appear to furnish clear evidence that these minerals 

were formed without the introduction of any new 

material. 

Alteration to silicate minerals.-The type of metamorphism consisting of alteration to silicate minerals is 

frequently referred to as "contact" metamorphism. 

The writer has refrained from the use of this term 

because of the two most striking features in the distribution of rock of this kind in the Gold Hill quadrangle. One of these features is that the silicatemineral alteration has been effected with very little 

regard for the actual igneous contact. Perhaps one of 

the best localities to show this lack of relationship is 

on the southern boundary of the quartz monzonite 

body on the south slope of Montezuma Peak. Just 

east of the road leading up Barney Reevey Gulch the 

rocks in contact with the quartz monzonite are members of the central facies of the Oquirrh formation. 

They have been only slightly affected by the igneous 

rock, and in one place a limestone bed that appeared 

to have escaped even the usual bleaching was found 

essentially at the contact. The same beds as those 

just described are also in contact with the quartz 

monzonite about half a mile to the east, in the vicinity 

of the Midas mine. There appears to be no difference in physical conditions at these two localities, but 

at the more easterly outcrops the limestone beds have 

been almost completely replaced by silicate minerals. 

Alteration of this type was also noted at two localities in Spotted Fawn Canyon, both more than a mile 

from any outcrops of the quartz monzonite. These 

localities may, of course, be underlain by igneous rock 

at no great depth, but the fact remains that alteration 

of this type has occurred here, where there is no contact, and no evidence of it has been found at many 

places along the contact. 

The second feature in the distribution of this alteration is the fact that the rocks lying above the Ochre 

Mountain thrust have suffered essentially no alteration. 

In several places, particularly in the vicinity of the 

Lucy L mine, there are roof pendants in which nearly 

unaltered Ochre Mountain limestone rests upon highly 

altered members of the Oquirrh formation. The sides 

of the pendants are steep, and both formations are in 

equal proximity to the intrusive. 

This lack of rei a tion between the so-called "contact" 

metamorphism and the igneous contact has been 

emphasized by many authors, and the only excuse that 

is offered for bringing up the matter here is that the 

term is still used for alteration of this type, even though 

it is recognized that the term is inappropriate. It 

.. :KA!mp, 1. F., Notes on Oold Hill and vicinity, Tooele County, western Utah: 

Econ. Oeology, vol. 13, pp. 25&-256, 11l1S. 

hardly seems desirable to use so descriptive a term in 

this region where its lack of pertinence is so obvious. 

Individual occurrences of this alteration have several 

different habits. The most wide-spread of these is 

probably the localization of the silicate minerals to a 

single bed, between others that have been affected to 

only a very minor degree. This habit is well shown in 

the 760-foot level of the Western Utah Copper Co.'s 

Gold Hill mine, where two beds of limestone have been 

almost entirely converted to a mixture of silicates but 

are separated by a coarsely crystalline limestone, 

which yielded practically no insoluble matter on testing with dilute acid. In the Midas, Alvarado, and 

Cane Springs mines limestone beds that have been 

altered to silicate minerals have been developed in the 

search for ore i and in all three of these mines the 

altered bed has been the site of minor slipping that 

parallels the strike and dip of the bed. In other localities the silicate minerals are found as small irregular 

masses. At least some of these masses appear to have 

been localized by intersecting fractures, but whether 

or not all of these occurrences can be so explained is 

somewhat questionable. Finally, on the fourth level 

of the Cane Springs mine a tabular mass of silicate 

rock about 1 foot thick was found cutting across the 

bedding of the enclosing rocks nearly at right angles. 

In all these types of occurrence there is, in some 

localities, a suggestion that the alteration has been 

guided by preexistent minor fractures. Something of 

this nature is required in view of the lack of relation 

to the igneous contact. 

Mineralogically, there tend to be two main types of 

rock that are formed by the silicate alteration of the 

limestone beds. One of these is dark-colored and 

heavy and is composed almost entirely of green diopside and a brown garnet, probably near grossularite in 

composition. The other is a strikingly light-colored 

type in which white bladed wollastonite predominates. 

In general the wollastonite-rich rock is more widespread than the garnet-diopside mixture, which appears 

to be more or less confined to regions in which the 

intensity of metamorphism has been at a maximum, 

as indicated by· the nearly complete destruction of 

original minerals and texture in the sedimentary rocks 

and the adjacent quartz monzonite and by the occurrence in these places of tungsten, bismuth, and molybdenum minerals. Several specimens were collected in 

which the three silicate minerals occur together. In 

these specimens the colored minerals occur as rounded 

areas or as bands in the wollastonite, and thin sections 

cut from such areas indicate that the wollastonite was 

the latest mineral to form (pI. 8, A). 

Variations from these two types of alteration are 

rather numerous but are quantitatively of distinctly 

minor importance. Perhaps the most interesting of 

these unusual facies are found in the immediate vicinity of ore bodies. Microscopic examination of garnet­

-

IGNEOUS METAMORPHISM 93 

diopside rocks from such localities shows that locally 

zoisite, humite, and an amphibole near actinolite have 

partly replaced the garnet and diopside. In such 

specimens also microscopic crystals of titanite and 

apatite may be also present. The wollastonite rock 

was not found to contain these later minerals. In 

several of the gold mines, however, wollastonite has 

been replaced almost completely by the hydrated 

magnesium silicate, spadaite (MgO· Si02• 2H20). (See 

pI. 8, 0.) 

A more wide-spread variation, which, however, 

seems to be most abundantly represented near the ore 

bodies, consists of a chloritic replacement of the other 

silicate minerals. Both the garnet-diopside facies and 

the wollastonite facies appear to have been subject to 

such a replacement. Both green and colorless chlorite 

were noted, generally accompanied by either quartz or 

calcite. In many of the specimens the chlorite is in 

the form of microscopic rosettes, which in some places 

are embedded within quartz areas and in others 

embayed by the quartz. 

The silicate alteration of rocks that originally contained minerals other than calcite is an additional 

facies of metamorphism. The sandstone members of 

the Woodman and Oquirrh formations, which have 

only a relatively small content of calcite, characteristically change to a light-colored, heavy rock that is 

composed of diopside and quartz. The brown color 

shown by weathered surfaces of the unaltered rock is 

absent from the metamorphosed equivalent, suggesting 

that the small amount of iron normally present was 

incorporated into the newly formed diopside. 

Many of the metamorphosed quartz-rich rocks were 

also found to contain orthoclase in amounts ranging 

from scattered tiny grains, which had developed in 

quartz near the diopside areas, to aggregates that included only small amounts of other minerals. Biotite 

was found in moderate amounts in some of these 

quartz-rich rocks, and garnet and wollastonite were 

noted in specimens that probably were originally 

rather calcareous sandstones. Sericite and chlorite 

were also found in some specimens, but, as in the 

garnet-diopside and wollastonite rocks, they appear to 

have formed at the expense of the earlier silicates. 

Tourmaline was recognized in only two specimens. 

Both of these rocks were originally sandy shales-one 

from the Cambrian in Spotted Fawn Canyon and the 

other from the Manning Canyon formation near the 

head of Overland Canyon. 

Alteration to jasperoids.-Alteration of the sedimentary rocks to jasperoids has been rather wide-spread. 

This phase of the metamorphism occurred, in general, 

rather near the contact with the quartz monzonite. 

(See pI. 2, on which areas of jasperoid are shown.) 

Its occurrence at the igneous contact is particularly 

striking east of Clifton, in the vicinity of the Minnehaha group of claims, where the interbedded sandstones 

and limestones of the Oquirrh formation have been 

almost completely altered for distances of more than 

100 feet from the contact. 

In other places faults older than the quartz monzonite have localized the formation of jasperoid. One 

of the most striking occurrences of this sort is the linear 

ridge composed of brownish-weathering jasperoid that 

extends north and south from the summit of Gold 

Hill. This mass marks a 'ault that separates the Ochre 

Mountain limestone and the Manning Canyon formation. The workings in the Western Utah Copper Co.'s 

mine have exposed this jasperoid on both the 300­

foot and 700-foot levels. The low jasperoid hill west 

of the Yellow Hammer mine, northwest of Clifton, 

is also clearly the result of alteration along the lines 

of two intersecting faults. 

Bodies of jasperoid probably were also formed in 

the Ochre Mountain limestone where the limestone 

is directly overlain by flat-lying beds of the Manning 

Canyon formation. This is particularly clear near the 

mouth of Barney Reevey Gulch and was probably 

also a contributive factor in the development of the 

abundant jasperoid found in the vicinity of the U.S. 

mine, south of the town of Gold Hill. 

The jasperoids are dense siliceous rocks, which have, 

in general, the appearance of cemented siliceous breccias, owing to the presence of several generations of 

quartz. In many specimens gray quartz is cemented 

by veinlets of white quartz, in the centers of which are 

sporadic vugs lined with terminated quartz crystals, 

but in other specimens white quartz fragments are 

set in a matrix of darker quartz. The cementing 

veinlets, when examined closely, are seen not to cut 

the older quartz sharply but to have gradational contacts, marked by a gradual change in color and a slight 

coarsening of grain outward. Locally similar changes 

may be observed within the older quartz areas around 

small vugs. White, glistening barite is in many places 

abundant in the jasperoids, especially where remnants 

of unreplaced limestone are present. Near the south 

end of the jasperoid mass forming Gold Hill plates of 

this mineral more than an inch in length were observed· 

set in a matrix of green chalcedony. Small quantities 

of sulphides, probably chiefly pyrite, are present in 

most of the occurrences, and weathered surfaces of the 

rock as a result have a deep reddish-brown coloration. 

Under the microscope the jasperoids present many 

interesting features. Quartz forms the great bulk of 

the material, and with it are associated small amounts 

of barite, sericite, calcite, a colorless chlorite (1), chalcedony, and opal. In most of the specimens a very 

finely crystalline quartz predominates. Within it are 

small inclusions of the colorless chlorite or ,sericite, 

splotches or bands of barite, and locally tiny blebs 

of opal (pI. 8, B). Remnants of replaced calcite are 

present in many of the specimens, and in one slide 

cleavage lines of calcite characteristic of the recrystal­
94 GOLD HILL MINING DISTRICT, UTAH 

lized limestones have been preserved (pI. 8, D). The 

fine-grained quartz in some places shows features that 

might be interpreted as desiccation cracks, and these 

appear to have partly controlled localization of the 

veinlets of later quartz that give the ro'Ck its brecciated 

appearance. The later quartz veinlets are more 

coarsely crystalline than the earlier quartz. In plain 

parallel light individual cry~tals appear to have devel- . 

oped normal to the walls of the veinlets, and lines of 

inclusions mark several stages in the growth of each 

grain. With crossed nicols, however, it may be seen 

that the present grain boundaries do not conform to the 

outlines marked by the inclusions. This recrystallization has apparently also extended into the areas of 

older quartz adjacent to the veinlets and accounts for 

the blurred outlines of the veinlets noted in the hand 

specimens. 

The time of formation of the jasperoid was clearly 

later than the initial recrystallization of the sedimentary rock, as the quartz has been found to replace the 

recrystallized limestones. Its relations at the U.S. 

mine indicate that it is also later .than the silicate 

alteration. There the ore minerals are limited in their 

distribution by the silicate rock and are later than that. 

rock. Some of the sulphide minerals, however, particularly arsenopyrite, are shattered and veined by the 

jasperoid, whose age must therefore be relatively late 

in the metamorphic sequence. 

The texture disclosed by the Inicroscope indicates 

that the initial replacement of the limestone by silica 

resulted in a gel-like material which contained at 

least some opal and in which were developed cracks 

resembling desiccation cracks. There is no positive 

evidence that all of the material was originally opal 

and that this changed to fine-grained quartz during 

the drying represented by the cracks, but this view 

seems not unlikely. The origin of the more coarsely 

crystalline quartz in the veinlets and its subsequent 

recrystallization, together with that of the older finegrained quartz, are also not susceptible of definite 

proof, but it might well be the result of slow deposition 

from expelled liquid and subsequent growth induced 

by the continued presence of the liquid. 

Dolomitization.-DoloInitization is one of the most 

widely distributed of the four types of alteration recognized. It does not affect, in general, the limestones 

near the quartz monzonite contact, but rather those 

at some distance from the intrusive. Thus, the Cambrian limestones in the Deep Creek Mountains and 

the northern part of Dutch Mountain have been locally 

converted to dolomite, as have the Ochre Mountain 

limestone on Dutch Mountain and the limestones of 

the Oquirrh formation in the vicinity of Twin Peaks. 

On the other hand, there has been some doloInitization 

of the Ochre Mountain limestone at the Western Utah 

Copper Co.'s mine at Gold Hill rather close to the 

quartz monzonite, but this seems to be of comparatively small extent. 

The Cambrian limestones and to a smaller degree 

the Carboniferous limestones have been changed by 

the alteration from a dense blue limestone to a rather 

coarsely crystalline rock which weathers to shades 

of light brown to chocolate-brown. Blowpipe tests 

on some of these dolomites show that manganese as 

well as iron is present, and it is probable that the 

coloring on the weathered surfaces may be ascribed to 

this metal. The marked distinction in color between 

the unaltered limestone and the dolomite makes it 

possible to prove the dependence of the alteration 

upon lines of fracturing in the limestone beds. This 

is best shown in the Deep Creek Mountains, where 

the alteration is comparatively slight. N ear the Garrison Monster mine, however, doloInitization of the 

Cambrian limestone has been so nearly complete that 

remnants of unaltered limestone are relatively rare. 

The time of dolomitization with respect to the other 

phases of metamorphism is not definitely known, as 

dolomitized bodies are not in contact with the other 

types of altered rocks. Carbonate veins, containing 

dolomite of apparently similar composition to that 

replacing the limestone, are, however, rather abundant 

in the mineralized quartz monzonite and appear to 

represent the latest stages of the magmatic after effects. 

ALTERATION OF THE QUARTZ MONZONITE 

The quartz monzonite stock has been altered over 

much of its extent. Several different facies of alteration may be distinguished in it, but they are not 

spatially so distinct as those recognized in the metamorphosed sedimentary rocks, although it is believed 

that the two groups may be directly compared. The 

oldest facies contains garnet, diopside, orthoclase, and 

other silicates. In many places these minerals, as well 

as the original constituents of the quartz monzonite, 

are altered to sericite and chlorite with some quartz, 

and this grouping is considered to form the second 

facies. it stage in which fine-grained quartz was introduced appears to have been still later and apparently was essentially contemporaneous with the formation of jasperoids . in the sedimentary rocks. The 

second of these three facies appears to occupy the 

largest area. In many specimens two or even all 

three may be observed in contact. 

Diopside-orthoclase alteration.-The alteration that 

introduced diopside and orthoclase was of relatively 

small extent. Most of the exposures are found in a 

linear belt extending from the Reaper and Yellow 

Hammer claims, in Clifton Flat, to the U.S. mine. 

In this zone diopside, orthoclase, and other silicates 

are rather abundant and at a few places have almost 

completely replaced the original minerals of the quartz 

monzonite over large areas. Similarly altered rock 

is found in other localities but in the form of small 

isolated patches, 

Orthoclase is the most abundant and wide-spread 

mineral in this group. In most localities it is asso~ 

-

IGNEOUS METAMORPHISM 95 

dated with other minerals, but in several places it 

appears to occur alone. A short distance north of the 

Yellow Hammer mine irregular veinlets and splotches 

of pink orthoclase have replaced the quartz monzonite 

over a considerable area and constitute almost half 

of its volume. As seen in thin sectiolls, the orthoclase 

is in the form of large crystals, much of it with a 

pseudopoikilitic habit due to the enclosure of incompletely replaced fragments of other minerals. Locally 

the orthoclase is replaced by white, finer-grained albite. 

Diopside is the next most abundant member of the 

facies. It is similar to that found in the metamorphosed sedimentary rocks and replaces all the original 

minerals of the quartz monzonite. Its localization in 

the altered areas of the quartz monzonite shows clearly 

that it has been introduced after the consolidation 

of the intrusive. In many of the occurrences of this 

mineral it is either bordered or invaded along its 

cleavage lines by an amphibole near actinolite. The 

diopside is, in part at least, older than the orthoclase, 

for remnants of similar orientation may be found embedded in a single orthoclase crystal. 

Titanite in euhedral crystals is also wide-spread and 

might almost be considered to characterize the facies 

as well as diopside or orthoclase. In some places it 

has formed as a swarm of tiny crystals, but in others it 

occurs as larger grains adjoining diopside areas. 

Garnet was found only in the vicinity of the Frankie 

and Lucy L mines, where it is locally abundant. Its 

general absence contrasts ",ith its wide-spread occurrence in the altered limestone that contains silicates. 

Scapolite, epidote, and black tourmaline were noted 

. in small amounts. The epidote and tourmaline are 

also found away from the metamorphosed areas coating joints in the quartz monzonite. This habit of the 

tourmaline is especially striking in the bottom of the 

gulch northwest of United States mineral monument 

no. 11. 

In all the areas that have suffered the diopsideorthoclase alteration, minerals characteristic of the two 

other groups have replaced the minerals of this group. 

The diopside appears to have been particularly susceptible to later alteration, and in many places it is 

almost completely altered to chlorite, calcite, or quartz 

or a mixture of these three minerals. 

Sericitization and chloritization.-The most extensive area showing sericitization and chloritization lies 

east of and roughly parallel to the northward-sloping 

portion of Rodenhouse Wash, extending from hill 5675 

on the north to a point about half a mile north of 

Goshute Spring on the south. On the north this area 

extends much farther westward and encloses the 

greater part of the relatively low-lying country west 

of the Climax mine. This area of intense alteration 

is situated immediately west of a series of barren 

quartz and quartz-carbonate veins that dip at a rather 

low angle to the west and are thought to mark a zone 

of reverse faulting in the quartz monzonite after its 

consolidation (pp. 89-90). 

. Evidence of this alteration is also prominently displayedin the quartz monzonite walls of the ore-bearing 

quartz veins, but in these the altered zone does not as 

a rule extend more than a few feet from the vein. The . 

characteristic minerals are also developed in most of 

the exposures of the altered rock of the diopsideorthoclase phase. 

In the Rodenhouse Wash area the igneous texture is 

largely and in places completely destroyed, and the 

resultant rock is a rather pale greenish-gray finegrained aggregate of sericite and chlorite, cut by 

reticulating veinlets of quartz. The microscope shows 

that the dark minerals are the first to be attacked, 

and these are followed by plagioclase, orthoclase, and 

quartz in the order named. In the less altered portions 

the outline of the former feldspar crystals is preserved 

by an aggregate of matted sericite of slightly different 

grain size than that in the remainder of the rock, but 

as the alteration becomes more intense even this 

remnant of the old texture is lost. The altered wall 

rocks of the veins are similar in appearance and 

composition. 

The relation between the sericite and chlorite is 

not clearly understood from the specimens studied. 

In the less altered rocks chlorite tends to be localized 

in the original dark minerals and sericite in the feldspars, but in the more highly altered rocks this is not 

true. From the several specimens in which the two 

minerals are in contact it is difficult to determine their 

relative age. In some places remnants of chlorite 

appear to be enclosed within masses of sericite and 

might therefore be thought to be earlier. In other 

places veinlets of quartz and chlorite cut across sericite 

areas and must be later. Finally, in several specimens 

the relations observed might be interpreted to indicate 

that either one or the other of the two minerals was 

formed first. These relations seem to be most easily 

explained by assuming that the two are essentially 

contemporaneous and that locally, depending upon the 

physico-chemical conditions, either mineral may have 

replaced the other. 

Sericite is the more abundant of the two minerals. 

The proportion varies widely in different specimens, 

and in places either one may be present to the exclusion 

of the other. By a rough estimate, whose only value 

lies in indicating the. order of magnitude, sericite is 

between 5. and 10 times as abundant as chlorite. 

Introduced quartz and calcite are found in many of 

these altered rocks. Almost all of the quartz is clearly 

later than the chlorite and sericite, cutting across them 

as veinlets or replacing them in bulk. It is similar in 

appearance and habit to the jasperoidal alteration 

product next described. 

Silicijication.-8ilicification of the quartz monzonite, corresponding to the formation of jasperoids in 
96 GOLD HILL MINING DISTRICT, UTAH 

the sedimentary rocks, bas occurred, for the most part, 

on a microscopic scale. The only place where it was 

found to have occurred on a large scale was underground in the Western Utah Copper CO.'s Gold Hill 

mine, where a rather large mass is exposed at several 

places along the western contact 6f the limestone with 

the quartz monzonite. The partial replacement of the 

quartz monzonite by microscopic quartz appears to 

have been rather wide-spread in the region between 

Lucky Day Knob and Gold Hill and is shown with 

particular abundance in specimens taken in the 

vicinity of ore bodies. 

The silicified rock differs from the jasperoid texturally. It is almost invariably somewhat coarser 

grained, and only one of the specimens examined 

showed the successive generations of quartz that are 

so marked a feature of the jasperoids. Vugs are 

almost entirely lacking. The silicification produced 

either veinlets cutting the quartz monzonite or 

irregular masses of quartz that form a matrix around 

the remnants of unattacked minerals. In one specimen 

showing almost complete silicification the quartz grains 

instead of having their usual anhedral habit, are in the 

form of laths, which show in some places a subparallel 

orientation (pI. 9, A). 

Sericite, chlorite, barite, and an iron-rich carbonate 

are in places associated with the quartz. The chlorite 

may be either green or colorless in thin section, but 

the colorless variety is the more characteristic. It is 

difficult to determine definitely whether or not the 

sericite and chlorite are invariably earlier than the 

quartz or are in part contemporaneous with it. Some 

of the specimens suggest strongly that small amounts 

of these minerals are of the same age as the quartz. 

Barite was recognized in only one specimen, as 

microscopic crystals within a veinlet of the fine-grained 

quartz. The carbonate, which is in part at least an 

ankerite (index of refraction of CJJ near 1.70), occurs as 

megascopic rhombs in the quartz or as veinlets cutting 

the quartz. Barite and ankerite were both found with 

quartz in the same veinlet and were presumably deposited at the same time. These minerals were not 

seen in quartz containing what was thought to be 

contemporaneous chlorite or sericite, however, and it 

is suggested that the silicification continued over a 

considerable period of time, in the early stages of 

which chlorite and sericite were deposited and in the 

later stages barite and ankerite. 

OOMPARISON OF THE ALTERATION OF THE SEDIMENTARY 

ROOKS AND THE QUARTZ MONZONITE 

In comparing the results of the metamorphism of 

the sedimentary rocks and that of the quartz monzonite, three features may be noted that appear to bear 

upon the process-the phases of alteration bear definite time relations to one another; the phases recognized in the quartz monzonite overlap to a far greater 

extent than those in the sedimentary rocks; and phases 

that are prominent in the one may be absent or unimportant in the other. 

The first of these observations has been emphasized 

in the descriptions of the individual phases, and the 

consistency with which all the specimens collected 

showed the same succession appears to warrant the 

generalization that the metamorphism was accomplished over a relatively long period of time, during 

which the conditions under which the alterations took 

place changed progressively in such a way that periodically groups of minerals already formed were no longer 

stable and were replaced by a new set. 

The three phases that were distinguished in the 

alteration of the quartz monzonite not only overlap 

spatially to a marked degree, but there also appears to 

be a mineralogic overlap between the second and third 

phases. These two features are only rarely observed 

in the altered sedimentary rocks. The cause of this 

distinction is not entirely clear, but it seems most 

reasonable to infer that it is the result of an essentially 

continuous passage of the metamorphosing fluids 

through the major fractures in the quartz monzonite, 

from which they were derived, as opposed to a discontinuous flow through the outlying sediments. 

The fact that phases present in the quartz monzonite may be essentially lacking in the sediments, or 

vice versa, is probably in large part the result of the 

different composition of these two kinds of rock. The 

lack in the igneous rock of a corresponding phase to 

the recrystallization in the sediments obviously cannot 

be explained in this way but is better interpreted as 

indicating that the quartz monzonite was still largely 

molten at the time of recrystallization. The silicate 

alteration of the sedimentary rocks was clearly very 

similar to the diopside-orthoclase alteration of the 

quartz monzonite-so similar, in fact, that it is almost 

impossible to distinguish the intrusive contact in 

places where this kind of alteration has taken place. 

There is, however, a distinction between them that 

appears to have a bearing on the later alterationthe absence of orthoclase in the altered limestones. 

This is clearly the result of the low alumina content 

of the unaltered limestone. Eskola 21 has shown 

that rocks in which the alumina content is too low 

to permit the development of feldspar commonly 

contain garnet. Conversely, the relative rarity of 

garnet in the quartz monzonite appears to show that 

it contained sufficient alumina to satisfy the K20 

content of the solutions causing metamorphism. 

The wide-spread sericite-chlorite alteration of the 

quartz monzonite is for the most part lacking or only 

sparsely developed in the sediments. If this phase is 

considered to be the result of the hydration of older 

aluminous silicates of magnesium, iron, or potassium, 

it is apparent that the explanation may be found in 

the fact that such silicates are far more abundant 

" Eskola, P., The mineral facies of rocks: Norsk. gaol. Tidsskritt, vol. 6, pp. 143­

l~ 192O. 

= 
U.S. GEOLOGICAL SURVEY 	 l'ROFESAIONAL PAPER 177 PLAT}] 8 

A. 	 WOLLASTONITE (w) REPLACING GARNET (g) IN METAMORPHOSED 

OCHRE MOUNTAIN LIMESTONE. 

Jllain light.. 

B. JASPEROm FROM THE U.S. MINE. WITH INCLUSIONS OF 


OPAl, IN QOAHTZ. 


Plain light. Opal is mineral with high relief. 

C. WOLLASTONITE HEPLACED BY SPADAITE. 

Plain light. w+ ",TollMlonite remnants. 

D. PHESERVATION OF CAIJ~ITE CLEAVAGE LINES IN JASPEROm. 
1J.S. GEOLOGICAL S1JRVEY PROFESSIONAL PAPER 177 PLATE 9 

A 

A. ELONGATED QUART7- GRAINS IN SILICIFIED QUART7- MON7-0'lITE, SHOWING TE'>DENCY TOWARD PARALLEL ORIENTATION. 

Crossed nicols. 

B. SUCCESSIVE REPL-\CEMENTS IN A SPECIMEN FHOM THE TlJNGSTEN-BEAHlNG PIPE ON THE REAPER CLAIM. 

PLain light. CJ E-pidote; <1, diopside; u. amphihole; ap, apatite; c, caldLe. 

C. APATITE (ap) AND MOLYBDENITE (m) IN AMPHIBOLE, FHOM HEAPER CLAIM. 
- - - 

 

97 

-1111!'!!!!!!!~=-"~~=~---------~-- -. _.- ..... -. ..~--. .. -----~ 

ORE 	DEPOSITS 

in the igneous rock than they are in either the 

altered or unaltered limestones or sandstones. The 

relation of dolomitization to composition is of course 

obvious. 

The course of the metamorphism may be summarized as follows: Coincident with the intrusion of the 

quartz monzonite, the invaded sedimentary rocks 

were subjected to a wide-spread recrystallization and 

bleaching, which appears to have been induced by 

circulating fluids, probably propelled by the heat of 

the magma and certainly impeded in their progress by 

such relatively impermeable material as the fault 

breccia along the Ochre Mountain thrust. After the 

consolidation of the now exposed portions of the intrusive rock, solutions containing large quantities of 

silica, potash, iron, and magnesia and probably small 

quantities of alumina traveled along fractures and 

reacted with both the intrusive and the invaded rocks, 

forming a group of minerals characterized by diopside, 

orthoclase, and garnet. Smaller quantities of minerals 

containing the so-called tt volatile constituents" of the 

magma, such as scapolite, tourmaline, and axinite, 

were also formed at this time, apparently somewhat 

later than. the bulk of the other minerals. After the 

deposition of these minerals the alteration became 

essentially one of hydration, and large areas in the 

quartz monzonite were converted to rocks containing 

much chlorite and sericite. This phase is almost lacking in the sedimentary rocks, probably because of 

their composition. Still later the solutions, becoming 

cooler, appear to have lost their corrosive power and 

instead deposited silica, much of it apparently in a 

gelatinous form, which afterward largely recrystallized to quartz. The final stage in the metamorphism 

resulted in the dolomitization of limestone, at considerable distances from the intrusive mass but clearly 

related to fracturing. This phase appears to be 

related to veins of quartz and ferruginous dolomite 

that cut the quartz monzonite and are later than the 

other products of alteration. 

ORE DEPOSITS 

The ore deposits found within the Gold Hill quadrangle differ from those of many other mining districts 

in that they are not closely similar deposits, which may 

be described as a group. On the contrary, the greater 

number of the explored ore bodies differ from one 

another to a marked degree, both as to form and as 

to composition. Hence, a general treatment of the ore 

deposits must be in the nature of a series of descriptions of individual ore bodies. As another section of 

this report (pp, 119-168) contains detailed descriptions 

of the mines and prospects, the descriptive part of this 

section is rather more brief than might otherwise be 

considered desirable and is designed to show primarily 

the relations that exist between the several kinds of 

deposits rather than their individual characteristics. 

Readers desiring more information about a particular 

type of deposit are therefore referred to the detailed 

descriptions and also to the sections on superficial 

alteration and mineralogy (pp. 104-107, 110-118). 

CLASSIFICATION 

As the ore bodi~s within the quadrangle include 

representatives of several different kinds of deposits, 

which vary not only in mineralogy but also in form, 

it is desirable first of all to classify them in order that 

they may be described systematically. Three methods 

of classification have been used more or less generallyone based on the metal present, a second based on the 

form of the deposit, and a third that utilized the supposed temperature of formation of the deposit, often 

referred to as a I( genetic" classification. The first of 

these is scarcely applicable to this area, for not only 

do many of the ore bodies contain minerals of several 

different metals, but several of the metals are found in 

utterly unlike kinds of deposits. Neither of the other 

two methods of classification is entirely satisfactory, 

because, if they are applied rigidly, they result either 

in the separation of rather closely related types of 

deposits or in the combination of unlike types. This 

difficulty is, of course, inherent in any system based 

on a single factor that attempts to classify objects 

that vary in several different ways. The following 

classification of the ore bodies found in the quadrangle is essentially a combination of the second and 

third methods noted above, with the primary emphasis 

placed upon form: 

1. 	Pipelike deposits locally containing tungsten and molybdenum. 

2. Veins: 

(a) 	Veins characterbJed by silicate minerals in the 

gangue. 

(b) 	 Veins containing chiefly quartz and metallio 

sulphides. 

(c) 	 Veins containing chiefly carbonate minerals with 

or without quartz. 

3. Replacement bodies: 

(a) Arsenio minerals dominant. 

(b) Copper-lead-silver minerals dominant. 

J'he replacement bodies have furnished by. far the 

greater part of the production recorded from the 

Clifton district. The pipelike deposits yielded small 

quantities of tungsten ores during the period of high 

tungsten prices; small quantities of. tungsten and 

copper and moderate amounts of gold have been 

produced from the silicate veins; and a fair tonnage 

of lead-silver ore was obtained from the quartz veins 

in the earlier part of the district's existence. 

PIPELIKE DEPOSITS 

The ore bodies belonging to the first group are pegmatitic masses in the quartz- monzonite that have a 

tubular or pipelike habit. The few deposits of this 

kind occur almost entirely in the nearly level stretch 

of country immediately north of the town of Clifton, 
98 GOLD HILL MINING DISTRICT, UTAH 

but a few are present in other areas underlain by the 

intrusive rock. 

The largest and best-known representative of the 

group is the tu~sten-bearing pipe on the Reaper 

claim. This ore body had an elliptical cross section 

at the surface, with a long axis of nearly 60 feet and a 

short axis of abou~ 30 feet. On the 50-foot level it was 

considerably smaller and had a circular outline, with a 

diameter of about 20 feet. On this level there are two 

apophyses from the pipe, one extending to the northwest and the other to the north-northeast. The 

pipelike habit persists only a short distance below this 

level, however, for on the bottom or 100-foot level the 

ore shoot has a lenticular shape, striking northeast. 

Smaller pipes were observed on the Centennial, Enterprise, and Doctor claims and on the property of the 

Yellow Hammer mine. In these the tubular form is 

clearly the result of localization of mineralization at 

the junction of two intersecting fractures, along both 

of which apophyses may extend for short distances 

away from the pipe. None of these pipes have been 

sufficiently developed to show whether or not the 

tubular habit changes downward to a veinlike habit, 

but it is perhaps significant that on all these claims 

there are veinlike masses of similar composition. 

The walls of the pipes are not well defined, for not 

only are there numerous irregular projections of 

pegmatitic minerals from the pipe into the wall rocks, 

but in many places there are isolated occurrences of 

these minerals in the quartz monzonite adjacent to 

the pipe. The igneous rock itself is rather thoroughly 

altered for some distance from the ore bodies. Two 

kinds of alteration were recognized. One has resulted 

in the formation of a rock of striking appearance but 

was quantitatively of relatively little importance. It 

consisted in the development in the quartz monzonite 

of pink perthitic orthoclase and a green amphibole 

that is near actinolite in its optical properties. Both of 

these minerals are also found in the pipes, but there 

they are much more coarsely crystalline. This phase 

of alteration, however, was not everywhere closely 

related in space to the pipes but locally took the form 

of irregular replacements of the igneous rocks some 

distance away from the pipes. The second and more 

wide-spref\d kind of alteration produced sericite, 

chlorite, and calcite in the quartz monzonite adjacent 

to the ore body. 

Both Butler 22 and Hess 23 have referred to these 

deposits as pegmatites, and, if variety of minerals and 

a large size for individual crystals are considered as 

characterizing pegmatites, these bodies may well be 

called by that name. 

The two most abundant minerals in the pipes are 

orthoclase and amphibole. Cleavage faces of perthitic 

orthoclase may be more than a foot across. The 

• .. Butler, B. S., Ore deposits of Utah: U.S. Geol. Survey Prof. Paper 111, pp. 47&­

477, 1920. 

.. Hess, F. L., Molybdenum deposits: U.S. Geol. Survey Bull. 761, p. 5,1924. 

mineral is pink, in contrast to the white albite that 

locally has replaced it. The amphibole is actinolit~ 

and occurs as sheds of crystals as much as 4 feet in 

length. Much of it is partly altered to micaceous 

minerals, calcite, and quartz, but even in these the 

amphibole cleavage is preserved. Black tourmaline is 

also abundant but tends to be found near the borders 

of the pipes, where it is generally accompanied by 

clear glassy quartz. Smaller amounts of diopside, 

epidote, titanite, zircon, garnet, and scapolite have 

also been recognized among the silicate minerals 

forming the pipes. 

Scheelite is the most abundant of the nonsilicate 

minerals. Very little scheelite could be found in the 

prospects at the time of this examination, but Butler, 

who examined the district before the active exploitation during the war, writes that on the Reaper claim 

<la body composed largely of scheelite 18 to 24 inches 

in thickness had been exposed for 4 or 5 feet along the 

strike and 3 or 4 feet below the outcrop. The scheelite 

occurs in large crystals, some of which are 4 inches long. 

One block of nearly pure scheelite on the dump was 

estimated to weigh fully 200 pounds." 24 

Apatite is also abundant in euhedral cl!Ystais that 

are commonly embedded in the actinolite, particularly near the base of the sheafs. Much of it at first 

glance resembles scheelite, but it lacks the cleavage 

commonly found in the tungsten mineral. Molybdenite occurs as small rosettes and is locally rather abundant. Chalcopyrite, pyrite, magnetite, and specularite may also be recognized in small amcunts.25 Gold 

is reported to occur in the pipes, and its presence is 

said to have led to the development of the pipe on the 

Reaper claim. 

There is some question as to the propriety of calling 

these deposits pegmatites, for the evidence is clear • that the minerals were introduced by a long series of 

replacements, first of the country rock and later of the 

earlier-formed replacing minerals. The localization of 

the pipes along intersecting fractures alone suggests an 

origin by replacement, and specimens taken at the 

borders confirm this view in that they show the 

minerals of the pipe embaying and replacing the minerals of the quartz monzonite. The fact that isolated 

patches of the introduced minerals are found in the 

walls of .the pipes is also difficult to explain except by 

replacement. 

The exact sequence in which the minerals forming 

the pipe were deposited cannot be ascertained from the 

specimens collected. A fair amount of information is 

available, however, and may be summarized as follows: 

Epidote and titanite were among the first minerals to 

form, as they have replaced the minerals of the quartz 

monzonite and have been replaced by other constit­

" Butler, B. S., op. cit., p. 476. 

" Photographs illustrating the occurrence 01 scheelite and molybdenite in deposits 

of this type in the Gold Hill area are included in two reports by F. L. Hess (Tungsten 

minerals and deposits: U.S. Geol. Survey Bull. 652, pIs. 12, A; 16, A, B, 1907; Molyb 

denum deposits: U.S. Gaol. Survey Bull. 761, pl. 5, B, 1924) • 
ORE DEPOSITS 99 

uents of the pipes. Zircon may be contemporaneous 

with them, and also possibly scheelite, of which Butler 

writes, "The scheelite was one of the earliest minerals 

to form. Much of it is in well-formed crystals, and 

little of it includes the other minerals." 26 The epidote 

and titanite are definitely earlier than diopside in a 

specimen from the Reaper claim, but this mineral is 

relatively rare. It is probable that the equally sparse 

garnet found in the pipes is also of this stage. The 

diopside in turn is replaced by actinolite along its 

cleavage planes (pI. 9, B). In other specimens actinolite appears to have formed immediately after epidote 

and titanite, without an intervening stage in which 

diopside was formed. Apatite and molybdenite are in 

many places associated with the sheafs of amphibole 

and are possibly of about the same age, although they 

generally appear to replace the amphibole (pI. 9, 0), 

as they interrupt and embay individual crystals. 

In all the specimens in which actinolite and orthoclase are in contact, orthoclase is clearly later, for it 

corrodes the amphibole and locally includes oriented 

remnants of it. Orthoclase in turn has been replaced 

by albite, in the few places that this mineral was 

recognized. The next mineral to form appears to have 

been tourmaline, with which is generally associated 

some glassy quartz that must have been developed 

somewhat later. The greater part of the tourmaline is 

dense black and rather coarsely crystalline, but locally 

this variety is replaced by a much finer grained blue 

tourmaline. The last stages in the formation of the 

pipe were the introduction of sericite, chlorite, calcite, 

and quartz. The sericite and chlorite are generally 

accompanied by either calcite or quartz or both, but 

these two minerals also continued to form for some 

time afterward. The sulphide minerals are associated 

with this group of minerals. 

The pipes are associated with veinlike bodies of 

similar mineral composition, and the large pipe in the 

Reaper claim changes downward into a deposit of 

veinlike form. This relation of the pipes to veins may 

be a result of proximity to the upper surface of the 

intrusive, which acted to dam the solutions forming the 

pipe and caused them to spread beyond the fissure to 

which they were limited at greater depths in the 

intrusive. That this may be the explanation is indicated by the localization of the pipes in the region 

north of Clifton, where it is clear, from exposures in 

the surrounding hills, that the original, nearly flat top 

of the intrusion must have been only a short distance 

above the present surface. 

VEINS WITH SILICATE MINERALS IN THE GANGUE 

Three subclasses of the veins with silicate minerals 

in the gangue may be distinguished for purposes of 

description, but there are almost continuous gradations 

between them. 

.. Butler, B. S., op. cit., p. 476. 

The first subclass includes the lenticular or veinlike bodies that are associated with the tungstenbearing pipes. They are mineralogically similar to the 

pipes, except that the size of individual crystals tends 

to be smaller and the content of scheelite is probably 

distinctly lower. 

The second subclass is found both in the quartz 

monzonite and in the sedimentary rocks and is characterized by a general fine-grained habit of the silicate 

minerals and by the general dominance of copper over 

tungsten as the valuable metallic constituent. These 

veins are restricted to the region between the Lucy L 

mine on the north and the town of Clifton on the south. 

These veins vary considerably in forni, ranging from 

the rather small lenticular masses found in places on 

the Gold Bond claim and the Copper Bloom group to 

the persistent lode on the Frankie claim, which has 

been developed for several hundred feet. All of them, 

however, appear to have been localized by earlier fractures or narrow sheeted zones. Some of these fractures give evidence of having been reopened over a 

long period of time. Thus the vein on the Frankie 

claim is in a narrow dike of quartz monzonite which 

was intruded along a fault that was active at a period 

long prior to the intrusion. After the intrusion, fissuring along the same line permitted the introduction 

of the silicate minerals, which in turn were cut by 

closely spaced parallel fractures, in which copper minerals are concentrated. 

Mineralogically these veins show a rather wide variation, and one vein may contain one or more minerals 

in abundance that are almost or entirely lacking in 

an adjacent vein. In general, epidote, titanite, and 

scheelite, which are thought to have been among the 

earliest minerals to form in the pipelike deposits, are 

relatively scarce in these veins. Garnet is particularly 

abundant, however, and with diopside appears to have 

been among the earliest minerals to form. Amphibole 

is distinctly later but is irregularly distributed, being 

very scarce in some of the deposits, particularly on the 

Gold Bond claim. Orthoclase also is of rare occurrence.. 

Tourmaline is wide-spread, and in some of the deposits, as in the Keno, Pole Star, and Copper Bloom 

claims, it was the only silicate mineral observed. Most 

of the tourmaline occurs as black bladed crystals, 

similar to those found in the pipes, and there is in 

addition some finer-grained blue tourmaline that is of 

somewhat later development. In the Gold Bond deposits specularite is widespread and is clearly later 

than tourmaline (pI. 10, B). 

The next minerals to be formed are characterized 

by the presence of boron, chlorine, and fluorine and 

include danburite, humite, scapolite, and fluorite. 

These minerals are surprisingly abundant, the veinlike occurrences of danburite in the Gold Bond claim 

being nearly a foot across and similar masses ofhumite 

on the Calaveras claim being several inches thick. 
100 GOLD HILL MINING DISTRICT, UTAH 

These minerals are clearly later than the other silicate 

minerals except sericite, and on the Gold Bond claim 

danburite and fluorite corrode and embay specularite 

(pI. 10, A). 

The final stage in the mineralization consisted in the 

introduction of small amounts of sericite, calcite, 

quartz, and the metallic sulphides, which have all replaced the older silicate minerals. Chalcopyrite is by 

far the most abundant sulphide, and most of the prospecting on these deposits has been for copper. Gold 

is present in small quantities in all of them, and in a 

few properties it has been the sole element present in 

anything approaching economic amounts. Pyrite is 

wide-spread in small amounts, and locally bismuthinite is fairly abundant. Tetrahedrite was recognized 

on the Copper Bloom group, and grains of galena and 

sphalerite were recognized on the Lucy L and Gold 

Bond claims, respectively. 

There is an obvious similarity in mineralogy and 

habit between the veins of this subclass and those of 

the first subclass. The chief differences between them 

appear to be a somewhat finer grain size, a general 

lack in deposits of the second subclass of the earlierformed minerals in the first subclass, and a greater 

variety and abundance of sulphide minerals in the 

deposits of the second subclass. Similarly there is a 

rather close relationship between the veins of this subclass and those of the third subclass. 

The veins of the third subclass have been exploited 

for their gold content. They are more widely distributed than those of the first two subclasses, although 

they appear to be considerably less abundant. They 

are restricted to limestone beds near the contact of 

the sedimentary rocks with the quartz monzonite. In 

all of them the gold ore is found in relatively small 

shoots that appear to be localized along minor structural features, such as linear igneous contacts, as in 

the Alvarado and the Rube mines, or along fractures 

parallel to the bedding, as in the Cane Springs and 

Midas mines. 

The Cane Springs, Alvarado, Midas, and two smaller 

deposits are very similar in character and may be 

considered as a unit. The ore is found in limestone 

that has been almost completely altered to silicate 

minerals and resembles very closely similarly altered 

limestones that are wide-spread throughout the district. 

Zoisite and vesuvianite are relatively rare constituents 

of the rock and appear to have been the first minerals 

to form during the alteration. They were succeeded 

by equally small amounts of garnet and diopside. 

The bulk of the rock in all the mines, however, is made 

up of white bladed wollastonite which is invariably 

later than the other silicates. This in turn has been 

widely altered to spadaite (see pI. 8, B). 

The last stage consisted of the introduction of the 

metallic sulphides with quartz and calcite. The 

observed relations between the quartz and calcite indicate either that there were several generations of each 

or that conditions of temperature and pressure varied 

so that first one and then the other might be deposited. 

Chalcopyrite is by far the most abundant sulphide, 

but the quantity found varies in the different mines. 

It is relatively abundant in the Cane Springs mine 

and rather scarce in the Alvarado. Pyrite, bornite, 

arsenopyrite, and galena have also been recognized in 

the ore specimens. Molybdenite has been reported 

from the upper levels of the Cane Springs mine, but 

its relations to the other sulphides are not known. It 

is extremely probable that the gold in the ores of these 

mines is essentially contemporaneous with the quartz, 

calcite, and sulphides, for all the specimens of ore that 

were examined contained some of these minerals. On 

the 200-foot level of the Alvarado mine several small 

pipes of ore were stoped that were not connected with 

the main shoot, and in these there were apparently 

practically none of the silicate minerals that form so 

large a proportion of the other ore shoots. The gangue 

in these places was composed almost entirely of quartz 

and calcite. Kemp has described ore from the Cane 

Springs mine in which gold was embedded in some of 

the silicate minerals,27 and there may therefore be 

some occurrences of the mineral that are not related to 

the introduction of quartz. It seems very improbable, 

however, that the amount of such gold is very great. 

The ore at the Rube mine is somewhat different from 

that described above. Most of it is composed of limestone, partly or completely replaced by quartz, sericite, 

calcite, and several metallic minerals, among which 

gold, pyrite, and galena are the most abundant, although chalcopyrite, spalerite, pyrrhotite, and arsenical boulangerite have also been recognized. Bismuth 

is shown by analysis of the ore, but no bismuth minerals were recognized in the specimens collected. One 

portion of the new ore shoot in the mine, however, was 

of radically different composition and appears to provide a connecting link between the Rube and the other 

deposits in this subclass. This part of the shoot contains as the earliest-formed minerals small quantities 

of zoisite, scapolite, and muscovite and rather large 

quantities of molybdenite. These have been replaced 

by green and colorless chlorite, which with calcite, 

makes up a large part of the rock. Pyrite is also 

abundant, particularly near the borders of this phase 

of the ore, but quartz is relatively rare. 

The remaining deposit in this subclass is that on the 

property of the Wilson Consolidated Mining Co. Here 

a bed of limestone intercalated between sandstones 

contains a small shoot of ore locally rich in gold and 

bismuth. The bulk of the ore is composed of coarsely 

crystalline white calcite, undoubtedly derived from 

the original limestone, in which are veinlets and 

enhedral crystals of quartz (pI. 10, D). Locally small 

II Kemp, J. F., Notes on Gold Hill and vicinity, Tooele County, western Utah: 

Eoon. Geology, vo1. 13, p. 258, 1918. 
ORE DEPOSITS 101 

quantities of orthoclase and sericite are also found. 

Bismuthinite, scheelite, and native gold were the only 

hypogene metallic minerals recognized. 

This class of veins with silicate minerals in the 

gangue present an almost continuous sequence from 

the pipelike deposits in which silicate minerals are 

dominant and quartz, carbonates, and sulphides are 

relatively rare to deposits like the Copper Bloom or 

Wilson Consolidated, in which the silicates have been 

reduced to a single variety, and the bulk of the ore is 

composed of quartz, carbonates, and sulphides. The 

transition is marked more or less definitely by a 

uniform decrease of the earlier-formed minerals and 

a comparable increase in the younger ones. In all the 

deposits there is a clear dependence of localization 

upon earlier-formed fractures. On the other hand, 

there is relatively little relation between the character 

of the ore and the character of the wall rock, except 

for the obvious restriction of wollastonite and other 

lime-rich silicates to deposits formed in limestone. 

VEINS CONTAINING CHIEFLY QUARTZ AND METALLIC 

SULPHIDES 

, The veins characterized by quartz and metallic 

sulphides are found chiefly in the quartz monzonite, 

but some are known to occur in the sedimentary rocks. 

They have a wide distribution throughout the intrusive 

mass, showing no discernible tendency toward localization. The veins are found along fissures, many of 

which can be definitely proved to be minor faults, or, 

as in'the Cyclone mine, along dikes. Most of the veins 

show a postmineral gouge along one or both walls. A 

general northerly strike and westerly dip are characteristic, but exceptions to both are not uncommon. 

Sericite, chlorite, and quartz have been introduced 

into the quartz monzonite where it forms the wall 

rock of the veins, but it is in most places impossible 

to determine the amount of such alteration that may 

be attributed to vein forma,tion, because of the mineralogically similar regional alteration of the igneous 

rock. There appears to have been essentially no 

alteration of the wall rock adjacent to the few veins 

that occur in the sedimentary rocks. 

Like those of the preceding class, these veins are 

rather variable in mineral composition. The variations, however, are expressed in the metallic minerals 

present, and there appears to be a rather complete 

series showing the stages in the variation. 

A subclass that, appears to be most closely related 

to the veins described in the preceding section is 

typified by the bismuth-bearing gold quartz vein on 

the Lucy L group of claims. This deposit is a lenticular body of quartz containing bismuthinite and native 

gold, enclosed in quartz monzonite. The greater 

abundance of quartz and the absence of orthoclase 

definitely distinguish this ore from the gold-bismuth 

ore at the Wilson Consolidated mine, but there is 

obviously a rather close resemblance between them. 

A second subclass contains arsenopyrite and quartz. 

Such veins are fairly abundant throughout the quartz 

monzonite area, but, except for the one on the Boston 

claim, they have been only slightly developed. The 

Boston vein contains also small quantities of other 

sulphides and in addition is reported to carry $14 to 

the ton in gold. 

The most abundant veins in this class and about the 

only ones that have yielded any significant tonnage 

of ore are the qua,rtz veins containing the sulphides of 

the base metals. The Cyclone, Success, and Southern 

Confederate veins are representa,tive of this subclass. 

They are restricted to the quartz monzonite but are 

scattered over the greater part of its outcrop. Many 

of these veins may be tmced for long distances along 

their strike, but ore shoots have proved to occur rather 

sparingly and to have rather small dimensions. 

The ore contains arsenopyrite, pyrite, sphalerite, 

galena, chalcopyrite, arsenical tetrahedrite or antimonial tennantite, and aikinite, the lead-bismuth sulphide. These sulphides are rather erratically distributed throughout the ore shoot, one predominating 

in some places and another in others. In polished 

sections arsenopyrite is seen to have been the earliest 

sulphide to form, as it has in most pla,ces been thoroughly fractured and cemented by quartz and the 

other sulphides (pI. 10, E). Quartz is the only abundant gangue mineral, but fragments of altered wall 

rock are not uncommon constituents of the veins. 

Veinlets of an iron-rich carbonate cut both quartz 

and sulphides. 

The final subclass of veins in this group has furnished small quantities of rather rich .ore. They are 

quartz-tetrahedrite veins, in which the only metallic 

minerals are arsenical tetrahedrite, which is rich in 

silver, and small quantities of galena. One of these 

veins occurs in the quartz monzonite on the Undine 

claim, but the others are in sedimentary rocks, the 

bulk of them being found on the northern and northwestern slopes of Dutch Mountain. A variety of this 

subclass is represented by a tetrahedrite-galena vein 

on the Reaper claim south of the open cut. This 

contained barite in the gangue, in addition to quartz, 

and is thus a connecting link between these veins and 

those of the next class. 

VEINS WITH CARBONATE OR SULPHATE MINERALS IN THE 

GANGUE 

The veins that have carbonate or sulphate minerals 

in the gangue are of relatively little economic importance but are described here because they appear to 

represent the final stages in the mineralization of 

the area. They are rather widely distributed throughout the quartz monzonite and the adjacent sedimentary 

rocks. Many of the veins follow older structural features. Thus the quartz carbonate veins in Rodenhouse Wash are thought to occupy a zone of probable 

thrust faulting (pp. 89-90); and carbonate veins on the 
102 GOLD HILL MINING DISTRICT, UTAH 

north and south sides of Montezuma Peak follow linear 

contacts of the quartz monzonite with the sediments, 

which in turn were determined by old faults. On 

the Monocco claim a carbonate vein has been introduced along an older lead-bearing fissure. 

The veins with carbonates in the gangue show a 

considerable variety in composition, ranging from those 

in which the carbonate is relatively scarce and quartz 

predominant to those in which carbonates form the 

bulk of the rock and quartz is essentially absent. 

In many places the wall rocks of the veins in which 

carbonate minerals are in excess contain isolated crystals of the carbonate. 

The most striking feature of these quartz-carbonate 

veins is their texture. Almost all of them show a 

banding that is locally parallel to the walls of the veins 

but in most places is rosettelike or colloform. In 

some specimens such curved banding clearly reflects 

the outlines of inclusions of altered quartz monzonite 

(pI. 10, 0), but in many of them no in elusions can be 

found. Thin sections of the veins show remnants of 

different sizes of sericitized and chloritized quartz 

monzonite, replaced by several generations of quartz 

and carbonate. The carbonate is iron-bearing in almost all specimens, but the proportions of iron, magnesium, and calcium in the mineral appear to vary 

widely. For example, one specimen had indices of 

refraction indicating a content of more than 75 percent 

of FeC03, and, at the other extreme, the carbonate 

from a vein in Rodenhouse Wash had much less than 

25 percent. Small quantities of sulphides occur in 

some of the veins, but their presence is unusual. They 

appear to be limited to veins that contain relatively 

small amounts of carbonate. An occurrence of a 

pocket of rich gold ore is reported in one of these veins 

on the Troy claim, but there appears to be some doubt 

as to the validity of the discovery. (See p. 151.) 

Barite veins are not abundant and are limited to 

areas of Ochre Mountain limestone near the quartz 

monzonite contact. The two regions in which they 

were found in any quantity were on the southeast side 

of Ochre Mountain and on the northeast side of the 

large roof pendant north of Clifton. In both of these 

places they are more or less closely associated \vith a 

jasperoid resulting from alteration of the limestone. 

In the Ochre Mountain occurrence the veins are controlled by lines of faulting but in many places spread 

out from the fault and replace the limestone. The 

barite is coarsely crystalline and has a platy habit. 

Where pure it is creamy white, but most of it has a 

dull-gray color due to inclusions. These veins have 

been practically unexplored, but it seems probable that 

a moderate quantity of fairly pure material might be 

exposed by a small amount of work. 

ARSENIC REPLACEMENT BODIES 

The arsenic replacement bodies have been developed 

in only two mines in the quadrangle-the Gold Hill 

mine of the West~rn Utah Copper Co. and the Gold 

Hill mine of the United States Smelting, Refining & 

Mining Co. (locally known as the U.S. mine). The 

ore bodies in these mines are the largest ones in the 

Clifton district and have furnished a large part of the 

ore produced. 

In both mines the deposits are found within the 

Ochre Mountain limestone in roof pendants enclosed 

in quartz monzonite. The preference for the unaltered 

limestone as a site of ore deposition is striking, for 

wherever there has been extensive formation of silicate 

minerals, or where more siliceous rocks, such as the 

Manning Canyon or Oquirrh formation or the quartz 

monzonite, abut against the ore body, there is an 

almost complete lack of arsenic mineralization. Two 

other factors appear to have played an important part 

in determining the localization of the deposits. One 

of these is the presence of a major fracture through 

which the ore-bearing solutions could have traveled 

across the strike of the beds, and the other is the occurrence of one or more fissures essentially parallel to the 

bedding. The second factor appears to be required 

by the fact that locally unmineralized limestone beds 

may be found adjacent to the ore bodies in both mines, 

and that, in the U.S. mine at least, the beds which 

have been replaced are cut by minor faults parallel to 

the bedding. The combination of these two factors 

produces an ore shoot with a roughly triangular plan, 

the base of the triangle being the crosscutting fracture 

and the altitude being represented by the fracture 

parallel to the bedding. It would seem that these 

features show that the ore solutions found it difficult 

to react with the limestone for more than a relatively 

short distance away from the fractures through which 

they could circulate freely. 

Most of these arsenic-rich ore bodies are, in their 

unoxidized portions, made up of arsenopyrite. In a 

few places this sulphide has a bladed structure (pI. 11, 

A), and this habit is also sh9wn by isolated crystals 

of the mineral in unaltered limestone adjacent to the 

ore. No gangue minerals contemporaneous with the 

arsenopyrite have been recognized in this material. 

Most of the massive arsenopyrite, however, lacks the 

bladed habit and is apparently textureless when seen 

underground. Polished specimens of this kind of ore 

show that it is the result of a thorough brecciation by 

which almost all trace of the original bladed habit was 

destroyed. Small amounts of pyrite appear to have 

been introduced during the brecciation, {or in many 

places this mineral also is brecciated, but by no means 

to the extent of the arsenopyrite. Still later, quartz 

was introduced into the brecciated sulphides, accompanied by small quantities of sericite, sphalerite, 

galena, and chalcopyrite (pI. 11, B). The introduction 

of silica appears to have continued over a long period, 

and locally it has largely replaced the arsenopyrite, 

the interior of the sulphide fragments apparently 

being particularly susceptible (pI. 11, 0). In the U.S. 
ORE DEPOSITS 103 

mine the introduced quartz is locally continuous with 

a jasperoid alteration product of the sedimentary 

rocks. 

In both the Western Utah and U.S. mines the 

arsenic ore bodies are associated with ore shoots that 

are valuable chiefly for their lead-silver content and 

contain relatively small amounts of arsenic. Such ores 

are characteristically found either along the wall of 

the arsenic ore or, as in the U.S. mine, replacing the 

same limestone bed in which the arsenic ore occurs, 

but beyond the arsenic ore in a direction away from 

the major fracture through which the mineralizing 

solutions are thought to have traveled. Where the 

relations between the two types of ore have not been 

masked by subsequent alterations it is clear that the 

arsenopyrite ore bodies are invariably the older. 

COPPER-LEAD-SILVER REPLACEMENT BODIES 

Three subclasses of the replacement ore bodies containing copper, lead, and silver may be distinguishedthose associated with the arsenic ore bodies, those in 

the Oquirrh formation, and those characterized by 

barite in the gangue. 

The lead-silver replacement bodies associated with 

the arsenic ore bodies are restricted to the occurrences 

of Ochre Mountain limestone in the Western Utah and 

U.S. mines. They have in many places a peripheral 

position with respect to the arsenic ore and are generally more distant from the mineralizing fissure. The 

relation of these ore shoots to fractures parallel to the 

bedding is particularly well shown by the "lead 

fissure" on the tunnel level of the U.S. mine. In the 

lowest of the three ore bodies in the Western Utah 

mine, ore of this type away from the mineralizing 

fracture is restricted to a single limestone bed 

and is separated from arsenopyrite that has replaced 

a similar bed by several feet of garnet-diopside 

rock. 

All these ores contain some arsenopyrite. This 

mineral is distinctly older than the other sulphides 

and undoubtedly represents material deposited on the 

fringes of the main arsenopyrite ore bodies. Pyrite 

was the next mineral to form and is locally found 

almost to the exclusion of the other sulphides. It is 

in general rather thoroughly fractured and replaced 

by the later sulphides and quartz. Sphalerite is widespread throughout the ores and is invariably later than 

pyrite. It contains in many places inclusions of 

chalcopyrite and pyrrhotite in the form of dots and 

discontinuous veinlets. Chalcopyrite may also be 

found in irregular areas of microscopic size bordering 

the sphalerite, but it" is for the most part relatively 

rare in these ores. Pyrrhotite in large masses was 

recognized only on the 760- and gOO-foot levels of the 

Western Utah mine. On the upper level it was comparatively scarce and appeared to be present only 

adjacent to the mineralizing fracture. On the gOO-foot 

level, however, it was wide-spread and had replaced 

pyrite as the most abundant sulphide. This was the 

only place in the quadrangle where there appeared to 

have been a change in the hypogene mineralization 

with increasing depth. 

Galena was the next sulphide mineral to form. 

Locally it contains inclusions of the copper-bismuthlead sulphide, aikinite. Galena is not found in specimens from the U.S. mine that contain a mineral 

identified by M. N. Short, of the Geological Survey, 

as jamesonite, which, however, has the same relations 

to the other sulphides as galena. The two minerals 

appear to have been mutually exclusive, the formation 

of one or the other seemingly having depended upon 

the local concentration of antimony. Stibnite was also 

recognized in specimens from· the dump of the U.S. 

mine. 

The several sulphides are not uniformly distributed 

throughout these ore bodies. Pyrite or pyrrhotite is 

almost invariably by far the most abundant, but the 

proportions. of the other sulphides vary widely from 

place to place .. In the 234-foot level of the U.S. mine, 

for example, much of the sulphide ore shows a rude 

banding, caused by the separation of the sulphide 

minerals into individual layers. 

Gangue minerals are scarce in these replacement ore 

bodies. Most of them are composed of almost solid 

sulphides with small amounts of interstitial quartz 

and less abundant calcite veinlets. Near the margins 

the replaced limestone also acts as a gangue mineral. 

The factors localizing the ore shoots are the same as 

those that have been described as causing the distribution of the arsenopyrite ore bodies (p. lO2). 

The replacement ore bodies in the Oquirrh formation are more numerous than tho:;;e of the preceding 

subclass, but are much less extensive. They are found 

in the limestone beds of the Oquirrh formation both 

near to the quartz monzonite contact, as at the 

Monocco and Silver King prospects, and at some 

distance from the contact, as on the Walla Walla 

and Mohawk claims. 

These ore bodies occur in thin beds of limestone 

which are rather free from imp~ties and which are 

interbedded with sandstone and siliceous limestone. 

Mineralization extends outward into these beds, which, 

wherever these deposits are found, have dips less than 

30°, from steeply dipping fractures that are themselves 

mineralized. The dimensions of ~uch ore shoots are 

small, ore being rarely found more than 15 or 20 feet 

away from the mineralizing fracture, and at such 

distances it is not uncommon for only a portion of the 

favorable bed to be ore-bearing. The mineralizing 

fissure itself locally contains as much as 2 feet of ore, 

but the average thickness is less than 1 foot. In several 

places more than one favorable limestone bed is cut 

by a single fissure, and in that case all the limestones 

may be mineralized. 
104 GOLD HILL MINING DISTRICT. UTAH 

None of the prospects on deposits of this subclass 

have had sufficient work done to disclose the characteristics of the unoxidized ore. The oxidized ore in the 

fissures is almost invariably higher in copper and 

lower in lead than the ore from the replaced limestone 

beds, and it seems certain that this difference represents an original distinction. Small quantities of 

galena and chalcopyrite have been recognized in these 

ores and are the only remnants of the original introduction of sulphides. Analyses of the ore shipped to 

smelters show also small quantities of zinc, arsenic, 

and antimony, and -it is probable that sulphides of 

these metals were also present originally. The gangue 

of the ore in addition to the replaced limestone consists 

of fine-grained quartz and iron oxides. 

The third subclass of the copper-lead-silver replacement ore bodies is represented by the deposit at the 

Garrison Monster mine. Similar deposits occur at 

several nearby localities on the north side of Dutch 

Mountain: These ore bodies lie chiefly along minor 

reverse faults that generally dip at low angles and are 

essentially parallel to the major thrust faults that are 

so abundant in that region. The deposits occur 

exclusively in limestone or dolomit~, but individual 

beds of this composition have had no apparent influence on the localization of the ore bodies. Ore shoots 

are distributed sporadically along the fissures. They 

are relatively small in lateral extent, none of them 

having a strike length of more than 50 feet, but in the 

Garrison Monster mine, at least, they persist for considerable distances down the dip. In that mine, the 

ore shoots coincide with troughs in the fissure zone. 

Unoxidized ore is found only in the Garrison Monster mine on the tunnel leveL There it consists of 

relatively small amounts of pyrite and sphalerite as 

residual remnants in galena. Like most of the sphalerite found elsewhere in the district, this mineral contains microscopic rounded inclusions of chalcopyrite. 

Associated with the galena in some places, particularly 

near the borders of galena crystals, are small areas of 

an antimonial tennantite. In addition to the limestone 

or dolomite wall rock, the gangue contains small 

amounts of fine-grained quartz and 'considerable quantities of barite. The barite appears to be in large 

part later than the sulphides (pI. 11, D). 

SUPERFICIAL ALTERATION OF THE ORES 

The fact that many ore deposits in unglaciated 

regions have been extensively altered at the surface 

is generally recognized .. This alteration is the result 

of the reaction of oxygen-charged surface waters upon 

the sup hide minerals in the ore body, producing, near 

the surface, minerals cnaracterized ,by a relatively high 

oxygen and low sulphur content, and locally, at greater 

depths, concentrations of redeposited or "secondary" 

sulphides. In many places such concentrations of 

redeposited sulphides are of considerable value, and 

much has been written concerning the mechanism and 

results of the procesS.28 

Several factors influence the character and extent of 

the alteration. Among these are the position of the 

ground-water table, the rate at which erosion of the 

region is progressing, the past climatic history, the 

recency of any differential uplift, and the physical 

character and mineral composition of the ores and their 

walls. The greater number of the ore bodies in the 

Gold Hill quadrangle have not been sufficiently developed to determine adequately the true importance of 

these factors, but from the evidence available it would 

appear that the last one has been the most influential. 

Iri. none of the ore bodies so far developed has there 

been any significant amount of enrichment through the 

formation of secondary sulphides. 

RELA,TION OF THE WATER TABLE TO SUPERFICIAL 

ALTERATION 

Only four mines in.the district have, so far as known, 

reached the ground-water table. These are the Western Utah mine at the 760-foot level, equivalent to an 

altitude of about 5,125 feet; the U.S. mine at the 234­

foot level, altitude about 5,430 feet; and the Success 

and Cyclone mines, in whose shafts the water table 

stands at altitudes of 5,450 and 5,950 feet, respectively. 

The Climax shaft was filled with water at the time of 

examination, but it is not known whether this water 

represents ground water or simply filling of mine openings in relatively impermeable rock. The altitude of 

the water table thus varies considerably in the places 

where it has been determined, and these localities 

also show a comparable variation in the distance from 

the water table to the surface. The data seem to 

indicate, however, that the water surface not only 

has a higher absolute altitude but is nearer.the existing surface in regions where the old erosion surface, 

discussed on page 61, shows a maximum amount of 

dissection. 

In all four of these mines the bottom of essentially 

complete oxidation is higher than the surface of the 

present water table. In the Western Utah and U.S. 

mines the distance betweeen the two is about 100 

feet, in the Cyclone mine from 30 to 35 feet, and in the 

Success mine 20 feet. Oxidation, however, may extend 

down to the ground-water level along fractured zones. 

The somewhat abrupt transition between rather completely oxidized ore and relatively unaltered sulphides 

some distance above the present water table points 

definitely to a recent wide-spread lowering of the 

ground-water level. The relation that appears to exist 

between the level and the old erosion surface suggests 

that such a lowering is the result of the normal faulting 

that is thought to have deformed the old surface. 

(See pp. 61-63.) 

" Emmons, W. R., The enriohment of ore deposits: U.S. Geol. Survey BulL 625, 

1917. Locke, Augustus, Leached outcrops as guides to copper ore, Baltimore, 1926. 
U.S. GEOLOGICAL SURVEY PROFESSiONAL PAPER 177 PLATE 10 

B 

c 

D E A. n~:PLACEMENT OF SPECULARITE (8) BY DANBURITE (d) AND FLUORITE (f), GOLD BOND CLAIM. 

B. HEPLACEMENT OF TOURMALINE (I.) RY SPECULARITE (8), GOLD BOND CLAIM (q, quartz). 

C. QUARTZ CARBONATE VEIN, 7.000 FEET EAST OF CLU'TON. 

V. QUAIlTZ (q) AND ORTHOCLASE (0) REPLACING CALCITE ee), WILSON CONSOLIDATED MINE (plain light). 

E. POLISHED SECTION SHOWING ARSENOPYRITE I"RAGMENTS CEMENTEU BY QUARTZ AND OTHER SULPHIDES, CYCLONE MINE. 
U.H. GEOLOGICAL SI'R\'EY PRO}'ESSIONAL PAPER 177 PLATE II 

B 

c D 

A. BLADED ARSENOPYRITE. TUNNEL I,EVEL, U.S. MINE. 


R. POLISHED SECTION SHOWING BRECCIATED ARSENOPYRITE (FeAsS), VEINED BY PYRITE (py), QUA.RTZ (q), SPHALERITf~ (0), AND GALENA. (g), U.S. MINE. 


r:. POLISHED SECTION SHOWING REPLACEMENT OF ARSENOPYRITE FRAGMENTS BY QUARTZ AND SERICITE, WESTERN UTAH MINE. 


D. THIN SECTION SHOWING BARITE (b) REPLA.CING SliLPHlDES (s), GARRISON MONSTER MIN"~ (pluinligbt; I, limestone). 
U.S. GEOI~OGrCAL SURVEY PROFESSIONAL PAPER 177 PLATE 12 

A 

c 

A. DENSE WHITE SCORODITE WITH ASSOCIATED CRYSTALLINE GREEN SCORODITE, WESTERN UTAH MINE. 

B. BROWN SCORODITE, WESTERN UTAH MINE. 

C. CRYSTALLINE SCORODITE FORMING FROM :\IETACOLLOID. 


Plain light. 

) 

ORE DEPOSITS 105 

RELATION OF THE PHYSICAL AND CHEMICAL CHARACTER I approaches beudantite in composition owing to the 

OF THE ORES TO SUPERFICIAL ALTERATION general occurrence of arsenopyrite in the ores. JaroAlteration site, also arsenical, is likewise widely distributed. The oj the pipelike deposits and oj veins with 

oxidized ore also contains some zinc, probably in the silicate minera(s in the gangue.-The pipelike deposits form of calamine, and copper, chiefly as the basic and the greater number of the veins with silicate 

minerals carbonates and chrysocolla. Small quantities of des­ in the gangue are alike in being relatively cloizite, mimetite, and wulfenite are also present. The little affected by oxidation. This condition arises in 

Cyclone mine was the only one in which the contact part because the silicate minerals are resistant to alterabetween the oxidized and unoxidized ore could be tion, in part because the low content of sulphides pre­ examined, and here there was no evidence of any vents the formation of much sulphuric acid, and in part appreciable accumulation of secondary sulphides at because the toughness and compact texture of the indithe contact. The copper content of the unoxidized vidual minerals do not permit the formation of cracks 

ore is low in this mine, ranging from 0.5 to 1.7 percent, and fissures through which surface waters may percolate and is apparently balanced by a sufficient quantity of and react with the ore minerals. In many places in 

carbonate in the vein to prevent any downward trans­ these ores hypogene sulphide minerals are found at or 

portation of copper. There is certainly no accumula­ near the surface, essentially unaltered. Even in spec­ tion of secondary copper sulphides at the present imens that show some alteration it is generally found 

water table in this mine. that the core of the mineral grain has not been affected. 

The Quartz veins containing arsenopyrite as the metallic changes that have been noted in these deposits mineral are not so thoroughly oxidized at the surface. are the local alteration of scheelite to cuprotungstite,211 

molybdenite Scorodite is widely distributed throughout these veins, to powellite, pyrite to iron oxides, and 

and all stages in its replacement of arsenopyrite may chalcopyrite to copper pitch which in turn is veined by be recognized, but the alteration is far from complete. copper carbonates and chrysocolla. These minerals 

This in part at least appears to be the result of the are locally accompanied by supergene silica in the 

massive character of the sulphide, in which relatively form either of chalcedony or of opal. The general few cracks unhealed by quartz may be distinguished. occurrence of copper pitch in place of the usual oxidaThe quartz veins containing tetrahedrite and galena tion products of chalcopyrite may be explained by the 

are still less altered. The sulphide content of these scarcity of pyrite and a consequent deficit in the 

veins is extremely small, and pyrite is totally absent. amount of sulphuric acid available during the alteraAlteration oj the carbonate and sulphate veins.-The tion. In ores like those found on the Copper Bloom 

carbonate veins are affected by weathering chiefly in group of claims, in which the ratio of quartz and sulthe elimination of carbon dioxide from the iron-rich phides to silicate minerals is higher, the secondary carbonates at the surface. Most of these veins on copper sulphides covellite and chalcocite have replaced weathered surfaces are colored various shades of brown chalcopyrite. This feature appears to be explained by the residual iron oxides. The barite veins are chiefly by the greater abundance of pyrite but is prob­ essentially unaltered. ably also accented by the greater mobility of solutions 

Alteration oj the arsenic replacement bodies.-The ar­ in the more readily fractured quartz. The hypogene senic replacement bodies in limestone provide the most bismuth sulphide, bismuthinite, was recognized only spectacular results of superlicial alteration. The out­ in ores containing small quantities of silicate minerals 

crop at the Western Utah mine consists of the hydrated in the gangue. It was everywhere pseudomorphously . 

iron arsenate, scorodite, with some intermixed iron altered to a mineral of varying appearance and optical . 

oxides, and originally had a length of about 300 feet properties that is probably close to bismutite in comand a width of nearly 200 feet. The ore shoot repre­ position. A small piece of native bismuth was found in 

sented by this outcrop and the next lower one are an area of the supposed bismutite, which in turn was 

both completely altered, and the third and lowest ore thought to be pseudomorphous after bismuthinite. I Alteration shoot is similarly &>ffected for most of its developed oj the quartz-sulphide veins.-Of the veins I' 

with'aquartz extent. The upper portion of the ore shoot at the gangue, those containing mixed sulphides U.S. mine has also been converted to scorodite. are almost completely altered at the surface. Galena 

The scorodite varies considerably in appearance and is the only sulphide that has been found near the surtexture. The greater part of it is Ii fine-grained dense face in these deposits, and it is generally surrounded 

brownish to greenish-brown rock with a conchoidal by rims of varying thickness of anglesite and cerusite. 

The fracture in which are sporadic vugs lined with finely stable lead mineral in the oxidized zone , however, crystalline material (pI. 12, B). In several places, is plumbojarosite, and this mineral probably contains 

however, there are considerable amounts of white mate­ the bulk of the lead in the ore shipped from the oxidized 

rial, which also has a conchoidal fracture. With this parts of these veins. Much of it is arsenical and 

locally is associated crystalline green scorodite (pI. 12, 

.. Hess, F. L., unpublislled notes. A). Thin sections show the relations of these differ35311-35---41 
106 GOLD HILL MINING DISTRICT, UTAH 

ent kinds of material to one another. The dense white 

material, in which remnants of arsenopyrite may locally be distinguished, is a metacolloidal substance 

which has a streaked or colloform habit and which 

is in part isotropic and in part has a fibrous crystallization. The refractive indices and birefringence of 

the nonisotropic portion are both somewhat lower 

than those of scorodite.· In sharp contrast with 

the white metacolloid is fine-grained crystalline green 

scorodite. The textures shown by the metacolloid do 

not pass across the contact into the true scorodite, 

and the grain size of the scorodite increases away from 

the contact, reaching a maximum in the terminated 

crystals that line the vugs (pI. 12, 0). Several specimens show that the green scorodite has formed at the 

expense of the metacolloid, and in a few places, as 

on the l50-foot level of the Western Utah mine, it 

has almost completely displaced the metacolloidal 

material. 

Similar stages may be observed in the brown to 

greenish-brown ore, but in this there are abundant 

microscopic flakes of iron oxide that impose their 

color upon the material. 11 the oxidation of arsenopyrite to scorodite, neglecting intermediate steps, is 

considered as represented by the equation 

it is clear that there is no excess iron to form the iron 

oxide observed in the brown ore, and it is necessary to 

assume that sufficient pyrite must have been present 

in the original ore to provide the excess iron. 

Locally the scorodite has been altered to a micaceous 

golden-brown mineral that appears to be arsenosiderite. 

This alteration involves the addition of lime, which is 

probably derived from the limestone wall rocks. 

The white metacolloidal mineral in the specimens 

studied appears to have been developed essentially 

in place, but there is abundant evidence to prove that 

scorodite has formed in the wall rocks at some distance 

from the hypogene sulphides. Veinlets of scorodite 

cutting the silicate minerals in the wall rocks are 

not uncommon. 

Alterati{)n oj the copper-lead-silver replacement bodies 

associated with the arsenic replacement bodies.-The 

oxidation of the copper-lead-silver replacement bodies 

associated with the arsenopyrite ore shoots has been 

distinctly influenced by the proximity of the arsenic 

ore. The bulk of such oxidized ore consists of mammillary, stalactitic, and powdery iron oxides, members 

of the jarosite group, and a varying quantity of scorodite, depending upon the distance from the arsenic 

ore shoot. The jarosite minerals include both jarosite and plumbojarosite, both of which contain the 

arsenate radicle locally, and in some places qualitative 

tests show that the sulphate radiCle has been almost 

completely displaced by the arsenate radicle. 

Together with this aggregation of minerals in the 

upper ore shoot of the Western Utah mine there was 

apparently a considerable amount of copper in the 

form of copper arsenates. The greater part of this ore 

has been stoped, and the relations and identities of the 

copper arsenates are not known. Small amounts of 

conichalcite were recognized in the lower ore bodies in 

the form of mammillary growths upon iron oxide and 

scorodite mixtures. Small quantities of olivenite and 

clinoclasite were also found in specimens studied by 

W.F. Foshag, of the National Museum. Zinc is present 

in the oxidized ores as the arsenate, adami te, which forms 

white prismatic minerals resting upon the iron oxides. 

The lead-bearing minerals in the oxidized portions 

of these deposits are not disseminated through the 

mass but are generally restricted to rather narrow 

lenticular masses. A jarositelike mineral is the only 

one present in any quantity in such lenses, but in 

composition it appears to range from plumbojarosite 

that is nearly free from arsenate to a hydrous arsenate 

of lead and ferric iron that is nearly free from sulphate. 

Doubtless some of this corresponds to the mineral 

beudantite. Small quantities of a white crystalline 

substance found in this material at the surface proved 

to be the lead chloroarsenate, mimetite. 

Associated with both the oxidized arsenic and copperlead ore shoots are considerable quantities of clay 

minerals. In most specimens these are isotropic and 

have a low refringence and are probably halloysite. 

Some, however, are distinctly birefrigent and probably 

belong to the leverrierite group. Locally masses of 

black wad are embedded in the clay. The greater part 

of the clay occurs in the walls of the oxidized ore, but 

some of it is intermixed with both the iron oxides and 

the scorodite. It appears to represent the product of 

the reaction between the silicate minerals in the wall 

rocks and the sulphuric acid set free during alteration. 

Small quantities of opal and quartz are also found with 

the other oxidation products. 

Several additional minerals are present in the Western Utah and U.S. mines where oxidation has extended 

downward to the present water table. Small quantities 

of secondary sulphides, of which marcasite is the most 

abundant, have developed in these places. Some 

chalcocite was recognized but in insufficient quantities 

to form a copper ore. The most surprising sulphide 

in this group is arsenopyrite, which apparently has 

not been previously recognized as a supergene sulphide. 

The mineral, whose identity was determined by W. 

T. Schaller, was found as a crystalline coating on a 

mixture of scorodite and iron oxides from the 760-foot 

level of the Western Utah mine. In addition to these 

sulphides gypsum is wide-spread at this horizon and 

locally has associated with it small quantities of native 

sulphur. The assemblage of minerals clearly indicates 

that, at this depth, the addition of oxygen that characterized the processes of alteration nearer the surface 
ORE DEPOSITS 107 

was no longer operative and was replaced by an 

abstraction of oxygen. 

On the lower levels of the Western Utah mine also, 

though not associated with the secondary sulphides, 

there are considerable quantities of siderite that has 

replaced the limestone wall rocks. In appearance this 

material is not unlike the smithsonite ores of other 

western mining districts, but chemical tests show that 

its zinc content is extremely low. 

Alteration oj the replacement bodies in the Oquirrh 

jormation.-The replacement bodies in the Oquirrh 

formation are almost completely oxidized. The copper 

ores in the fissures consist dominantly of dark-brown 

to black copper pitch, which contains remnants of 

chalcopyrite and is veined by malachite, azurite, and 

chrysocolla. The lead ores contain sparse remnants of 

galena, from which anglesite, cerusite, and plumbojarosite have been formed. Several specimens show 

that these minerals were formed in the order named, 

and each one at the expense of the preceding mineraL 

The process of alteration has apparently nearly reached 

completion, for plumbojarosite is the most abundant 

lead mineral in these deposits. In both lead and copper 

deposits secondary silica in the form of opal and chalcedony is present. 

Alteration oj replacement bodies containing barite.­

The lead replacement bodies with barite in the gangue 

have also been altered in a similar way. At the 

Garrison Monster mine, however, the proportion of 

cerusite to plumbojarosite is relatively high. 

AREAL RELATIONS OF THE ORE DEPOSITS 

In many mining districts it has been observed that 

different types of ore deposits are arranged in c.oncentric zones with respect to a central area, which is 

commonly occupied by an intrusive rock mass. The 

deposits of the successive zones are held to represent 

deposition at decreasing temperature away from the 

central area, and the mineralogic changes that are 

observed in them are considered to be the same as 

those found at different depths in a single vein, the 

deeper mineral facies in the vein being represented by 

a similar grouping in the inner zones on the surface. 

Emmons 30 has recently summarized the evidence for 

such a zonal distribution of ore. In view of the large 

number of different kinds of ore bodies occurring in 

the Gold Hill quadrangle, it is desirable to bring out 

in what respects the distribution of these deposits conforms to the ideal arrangement, and in what respects 

and for what reasons it appears to depart from a 

uniform zoning. 

Influence oj zoning on the distribution oj the ore 

deposits.-Almost all the ore bodies characterized by 

silicate minerals in the gangue are concentrated in a 

30 Emmons, W. R., Primary downward changes in ore deposits: Am. Inst. Min. 

Eng. Trans., vol. 70, pp. 964-997, 1924; Relations of metalliferous lode systems to 

igneous intrusives: Idem, vol. 14, pp. 29-10, 1926; Relations of the disseminated 

copper ores in porphyry to igneous intrusives; Idem, vol. 75, pp. 191-815, 1921. 

relatively narrow zone extending from a point near 

the town of Clifton to the vicinity of the U.S. mine. 

This zone coincides with a belt of normal faulting that 

is considered to be closely related in age to the intrusion of the quartz monzonite, and it has been suggested 

that the belt represents the primary channel through 

which the igneous rock was intruded (pp. 88-89). 

Such a relation between the site of intrusion and the 

higher-temperature ore deposits seems to be good 

evidence that areal zoning has to that extent been 

operative. 

Within this same zone, however, there are numerous 

representatives of other types of deposits, which 

clearly have been formed at lower temperatures. 

Thus on the Reaper claim, in addition to the tungstenbearing pipe, there is a quartz vein containing tetrahedrite, galena, and barite and a quartz-carbonate 

vein, both less than 300 feet from the pipe. SiInilarly, 

in the areas outside of the zone, deposits of notably 

different mineralogy are found in close proximity. At 

the Western Utah mine, on Gold Hill, for example, 

a gold-bearing lode with silicate gangue, a quartztetrahedrite vein, and arsenic and lead-zinc replacement bodies in limestone are essentially in contact 

with one another. 

There must therefore be some other factor than 

distance from the center of intrusion that has influenced the distribution of the ore deposits. It seems 

probable that this factor lies in the age relations 

between the mineralogic facies characterizing the 

different types of ore deposits. As has been noted, 

there is a demonstrable sequence for the several facies, 

the higher-temperature deposits being the oldest. The 

writer believes that to these differences in age is due 

the lack of zoning shown by the greater number of the 

deposits, and that in this district the time factor 

(resultant from such age differences) has been vastly 

more important in determining the distribution of ore 

bodies than the space or temperature factor that 

causes the zonal distribution. It is not improbable 

that the dominance of the time factor in this area is 

in large part the result of the repeated fracturing 

of the quartz monzonite (p. 89), which provided 

channels for the ore-depositing solutions in regions 

that might otherwise have been closed to them through 

sealing of the earlier-formed fractures by older, highertemperature ore bodies. 

It is obvious that if the time factor is as important 

as is thought, the period during which .ore deposition 

took place must have been a long one, because it 

must have included time enough for the ore-bearing 

solutions traveling through the same stretch of quartz 

monzonite country rock to cool from the temperatures 

at which the tungsten-bearing pipes were deposited to 

those which permitted the carbonate veins to form. 

The proposed relation between the recurrent fracturing in the quartz monzonite and the lack of a general 

zoning pattern in the distribution of the ore deposits 
108 GOLD HILL MINING DISTRICT, UTAH 

would imply that regions in which a zonal distribution 

of the ores is well defined have undergone essentially 

no fracturing during the period of ore deposition. 

Both Hills 31 and Knopf 32 have described districts 

in which the distribution of the ore deposits is markedly 

at vari~nce with that to be expected if there had been 

a simple zonal control. Both men came to closely 

similar conclusions, which may be summarized by the 

following quotation from Knopf: 

The principle that successive ore-forming differentiates 

(" distillates "), each with its own distinctive constituents and 

characteristics, are given off during successive stages of a progressively cooling magma will be found, it is here suggested, to 

be widely applicable in the study of ore deposition. As a modifying factor the principle of zonal distribution is recognized as 

having been operative in some districts, but of and by itself 

the principle of zonal variation in ore deposition is of very 

narrow application. 

The writer prefers the view that recurrent fracturing 

in the intrusive rock is of more importance inchanging 

the character of the ore bodies than distinctive composition of successive differentiates. The evidence for 

"this opinion is given in the section on the origin of 

the ores. 

Influence of the Ochre Mountain thrust on the distribution of the ore deposit8.-A singular feature in the 

distribution of the ore deposits is the barrenness of the 

formations above the Ochre Mountain thrust. In 

several places roof pendants within the quartz monzonite or reentrants of sediments into the intrusive rock 

are made up largely of Ochre Mountain limestone 

lying above the thrust, with only small amounts of the 

overridden beds beneath. The beds below the thrust 

are intensely metamorphosed and contain various 

kinds of ore bodies, but the overlying beds are essentially unaltered and in almost all places contain no 

ore bodies whatever. This difference in behavior cannot be attributed to any lithologic features of the 

overlying beds, because the occurrences of Ochre 

Mountain limestone beneath the thrust contain numerous and locally large ore bodies. It seems probable 

that the barrenness of the rocks above the thrust may 

be attributed to the fact that the thrust plane prevented the continuation upward of fractures that were 

forming in the quartz monzonite and in the rocks 

below the thrust and localized the flow of the solutions 

that were causing metamorphism and ore deposition. 

As' almost all these fractures appear to be genetically 

connected with the intrusive rock, it is likely that the 

zone of weakness represented by the thrust would 

deflect the fractures horizontally along itself and 

prevent their further upward extension. 

81 Hills, Loftus, The zinc·lead sulphide deposits or the Read-Rosebury district· 

Tll8mania Geol. Survey BUll. 23, pp. 86-88, 1915. . 

3> Knopf, Adolph, Geology and ore deposits 01 the Rochester district, Nev.: U.S. 

Geol. Survey Bull. 762, pp. 57-68, 1924. 

GENESIS OF THE ORE DEPOSITS 

The ore deposits within the quadrangle very clearly 

represent the final stages of the intrusion of the quartz 

monzonite stock. The evidence proving the close 

relationship between them lies in the obvious connection between metamorphism and the ore depositsparticularly the pipes and the veins with silicate 

gangue-and the dependence of the metamorphism in 

turn upon the quartz monzonite intrusion. The 

exposures within the quadrangle appear to provide a 

rather complete picture of the ever-changing results 

~ffect~ by the emanations given off by the solidifying 

IntruSIve. 

At the start of this final stage of the igneous activity 

the emanations resulted in the formation of anhydrous 

silicate minerals with, locally, tungstates in the form 

of scheelite. The minerals formed show that all the 

common rock-forming elements were contained in the 

emanations and, as they developed by the replacement 

of either. the wall rocks or the quartz monzonite, lead 

to the VIew that the material was simply a residuum 

of the rock Inagma made highly mobile by the concentration within it of the small quantities of volatile 

constituents originally contained in the magma. These 

constituents do not enter into the earlier-formed 

minerals, however, either because their concentration 

was not large enough to cause precipitation, or, more 

probably, because the temperature was too high to 

permit them to enter a stable solid phase. 

This assemblage of minerals was succeeded by one 

in which the minerals formed are made up not only of 

the rock-forming elements but also of the volatile 

constituents. Amphiboles, tourmaline, axinite, apatite, scapolite, fluorite, humite, and danburite for 

example, were formed during this period, in ~any places at the expense of the minerals of the first stage. 

In addition, iron oxides appear to have been formed 

at this time. 

The initiation of a third period is marked by the 

appearance of quartz and the metallic sulphides. 

Chlorite and sericite are essentially contemporaneous 

with these minerals and show that the emanations 

still contained some of the rock-forming elements, 

even though many occurrences of these minerals suggest that in large part they have developed at the 

expense of earlier-formed silicate minerals. This 

period, like both of the preceding ones, may be subdivided into successive steps. Thus, bismuthinite 

and arsenopyrite appear to have been among the 

earliest sulphides to form. Galena and tetrahedrite, on the other hand, are among the last and appear to 

have been deposited near the end of the period. 

The products of the final period are characterized 

by the almost complete absence of silicate minerals 

and metallic sulphides. During this period the em ana­
ORE DEPOSITS 109 

tions deposited silica (much of it probably in the form 

of a gelatinous substance that later recrystallized to 

quartz), barite, and carbonates. The carbonate minerals contain considerable quantities of iron and magnesium and indicate the persistence of these rockforming elements as constituents of the igneous 

emanations. 

Although the assemblages of these four periods are 

distinct mineralogically, they are by no means separated areally; in many places all four may be found 

in the same ore deposit, where they are intimately 

associated but clearly of different ages. This fact, 

together with the persistence of certain of the constituents, such as iron, magnesia, and silica, throughout 

the series, makes it highly improbable that there have 

been several emissions of distinctive composition from 

• the magma, as postulated by Knopf and Hills (see 

p. 108), but indicates rather that metamorphism 

and ore deposition have been one continuous process. 

The abrupt changes in mineralogy shown by the 

deposits of the four periods appear to have been the 

result of a constantly decreasing temperature, by 

which new mineral groups became the stable phase in 

place of the older minerals that they replaced. This 

view requires that the different elements contained in 

the emanations should have widely different fields of 

stability. Thus, fluorine and boron could have been 

precipitated during only one of the four periods, but 

magnesium, iron, and silicon appear to have formed 

stable compounds throughout the process, although 

it is recognized that the compounds formed differ for 

each period. 

Although it is probable that all cooling igneous 

emanations in general pass through successive periods 

more or less similar to those recognized at Gold Hill, 

it is obvious that the details of the process must differ 

considerably in different places. The individual 

minerals formed reflect not only the original composition of the emanations but also changing concentrations of the different phases contained in them, the 

rate of change in temperature, reaction with the wall 

rocks" and the presence or lack of equilibrium. The 

important feature, it would seem, is that the fluids 

that cause igneous metamorphism and ore deposition 

undergo a differentiation of the same or even a greater 

degree of complexity than that which has been determined for the igneous rocks themselves. 

The chief modifying factor in the progress of ore 

deposition appears to have been the presence of recurrent fracturing in the rocks within which the ores 

were being deposited. The evidence indicating that 

fracturing continued over a long period after the 

intrusion of the quartz monzonite is presented on 

page 89, and to this cause may be attributed many 

of the present features of the ore deposits found in 

the quadrangle. This factor can be used to explain 

the preservation of the pipelike deposits through the 

abandonment of the mineralizing channel by reason of 

renewed fracturing; had this not occurred, the mineral 

assemblages of the early periods would probably have 

been in large part replaced by those of the later periods. 

On the other hand, a channel once sealed by deposition 

of material from the emanations may be reopened and 

again filled by minerals of a much later period, as 

illustrated by the late carbonate veins that cut ore 

deposits of an earlier stage. 

It is possible that the existence of so many small ore 

deposits instead of a smaller number of large deposits 

is to be ascribed to recurrent fracturing. As renewal 

of fracturing may have caused the abandonment of old 

channels and the opening of new ones, it would appear 

that the process, if carried far enough, might easily 

result in so shortening the time during which ore 

deposition was operative at anyone place that the 

bodies of ore thus formed would be so small and of so 

low a grade as to be of relatively little value. 

FUTURE OF THE DISTRICT 

At the time of the last field work by the writer 

(1927) the production of the district had decreased 

to a small part of that made in the years after the completion of the railroad from Wendover. The reasons 

for this decrease were in part economic and in part 

inherent in the ore deposits themselves, but the two 

reasons were of different importance for each class of 

ore body. The future possibilities of the district may 

therefore be most readily discussed by a separate 

consideration of each type of deposit. 

Tungsten-bearing pipes and veins.-The production 

of tungsten from pipes and veins has been small and 

was made only during the war-time period of high 

prices. Although it is probable that similar deposits 

might be developed in the region between Clifton and 

the Lucy L mine-particularly at the upper contact 

of the quartz monzonite stock beneath the roof pendants that conceal much of the igneous rock in this 

region-it is doubtful if such deposits could be worked 

profitably at the prevailing prices for tungsten. 

Veins with silicate minerals in the gangue.-Two 

main varieties of the veins having silicate minerals 

in the gangue have been prospected: in one, copper 

is the valuable metal; in the other, gold. The copperbearing veins have been rather thoroughly prospected 

on the Frankie, Calaveras, Pole Star, and other claims, 

and several shipments of ore have been made from 

them. In general, however, the average copper content is too low and the ore bodies developed are too 

small for them to be worked profitably except when 

prices for copper are unusually high, and owing to the 

nearly complete extraction of these ores at the outcrop, 

where mining has been relatively cheap, it is doubtful if they will ever be of any importance. 

A different conclusion may be drawn concerning the 

veins in which gold is the valuable constituent. At 
110 GOLD HILL MINING 

least four mines have worked ore deposits of this 

type-the Rube, Alvarado, Midas, and Cane Springsand these have shown that the ore shoots, though small, 

contain sufficient gold to make properly conducted 

operations successfuL The known deposits have a 

rather wide distribution in the sedimentary rocks near 

the. quartz monzonite contact, but the outcrops of 

the ore deposits are relatively inconspicuous. It seems 

probable that careful prospecting in the sediments near 

the igneous contact may disclose other deposits of 

this class which contain either direct smelting ore similar to that at the Rube, or lower-grade milling ore. 

The tonnage of milling ore in a single one of these 

veins would probably be insufficient to warrant the 

erection of a mill, but it is probable that ore from several of them would justify the operation of one mill. 

Quartz-sulphide veins.-A large number of the 

quartz-sulphide veins have been prospected more or 

less thoroughly and have furnished some small shipments of ore, valuable chiefly for the content of silver 

and lead. The work that has been done has shown 

rather conclusively that the ore shoots are too small 

for any operations except on the most modest scale, 

and future production from deposits of this type will 

very probably be confined to occasional carload lots 

extracted by lessees. 

Carbonate-sulphate veins.-The carbonate veins have 

essentially no valuable metallic constituents and need 

not be further considered. If the demand for barite 

continues to increase, however, there is a possibility 

that deposits large enough to warrant mining opera:' 

tions may be developed. So little work has been done 

on the deposits containing barite, however, that it is 

difficult to predict their future importance. 

Arsenic replacement bodies.-The two important 

arsenic replacement bodies-in the Western Utah and 

U.S. mines-have, with the lead-silver replacement 

bodies associated with them, provided a large part of 

the district's production. The shipments ·of arsenic 

ore from the two mines were made during the period 

from 19H1 to 1925, when prices of white arsenic (As20 S) 

ranged from 7 to 20 cents a pound. Both mines still 

possess large reserves of arsenic ore, but the prevailing 

prices of 2 to 4 cents a pound for white arsenic since 

about 1925 have been too low to permit profitable 

operations. Should prices improve sufficiently, these 

mines would undoubtedly be able to provide a large 

quantity of ore. According to Clifford F. Rowley, 

manager, the Western Utah mine has 225,000 tons of 

proved ore, averaging 24 percent of arsenic. The 

quantity of arsenic ore developed in the U.S. mine was 

not ascertained but must be of about the same magnitude~ Only a minor amount of exploration has been 

directed toward the development of new arsenic ore 

bodies, but it seems probable that, if due regard is 

given to the factors which were operative in localizing 

the two known deposi1;s, additional ore bodies may be 

DISTRICT, UTAH 

found in regions where the Ochre Mountain limestone 

beneath the Ochre Mountain thrust is adjacent to 

the quartz monzonite. 

Copper-lead-sih,er replacement bodies.-The remarks 

made above concerning the quartz-sulphide veins are 

applicable also to the copper-lead-silver replacement 

bodies, for, except for the lead-silver ore associated 

with the arsenic ore deposits, the exploitation of these 

ore bodies has been, in general, disappointing. Some 

of the deposits, particularly those in the Garrison 

Monster mine, contain rather rich ore, but the ore 

shoots without exception are so small in cross section 

that the quantity of ore available is meager. 

Summary/.-A large tonnage of arsenic ore is developed in the quadrangle, and the possibilities of· increasing the amount are thought to be good. Profitable exploitation of the ore, however, must wait until 

the price of arsenic is higher than that which has 

prevailed in recent years. It is also considered that 

careful prospecting may disclose additional deposits of 

gold ore which, though of small size, may repay the 

discoverer. Possibly the district contains barite 

deposits that may be worked at a profit if the demand 

for this material increases. The remaining types of 

deposits are thought to be too small or too low in 

grade to provide any great future production. Many 

of these deposits, however, offer opportunities to 

small groups of individuals who, working with little or 

no overhead expense, might extract several carloads of 

ore at a satisfactory profit. 

MINERALS OF THE METAMORPHOSED ROCKS AND 

THE ORE DEPOSITS 

In this section the minerals are described in the 

order followed by Dana. 

NATIVE ELEMENTS 

Graphite (C).-Found as small flakes in the altered limestone 

wall rock in the Alvarado mine, associated with muscovite, 

quartz, calcite, and spadaite (?). Opal and a clay mineral are 

also present, but are probably supergene. 

Sulphl1,r (S).-Small quantities of native sulphur were recognized in the Western Utah mine at ground-water level. Marcasite, gypsum, and iron oxides were the most abundant 

associated minerals. 

Bismuth (Bi).-Small quantities of bismuth were found at 

the Wilson Consolidated and Lucy L mines. In the former a 

speck of native bismuth was embedded in bismuthinite; in. the 

latter it was associated with bismutite. 

Gold (Au).-Native gold is present in a number of the mines 

in the district, particularly those in which the gangue consists 

of silicate minerals. Previous observers have considered the 

gold to be contemporaneous with the silicate minerals, but the 

writer's observations indicate that it was introduced somewhat 

later and is more closely associated with quartz and sericite. 

Two varieties of gold were recognized in specimens from the 

Rube mine. One was in the form of microscopic specks widely 

distributed throughout the unoxidized ore. The other was 

coarser-grained and in the form of well-developed crystals and 

was observed in anglesite, cerusite, and other supergene minerals 

a.nd also resting upon iron oxides. The second variety was 

- ._._.._------­
MINERALS OF THE METAMORPHOSED ROCKS AND THE ORE DEPOSITS 111 

clearly formed during the oxidation of the ore. There was, 

however, no apparent enrichment during the oxidation, for the 

unoxidized ore has essentially the same content of gold as the 

oxidized ore. 

Copper (Cu).-Mr. Tiffany, superintendent of the Western 

Utah mine in 1925, reported that some native copper had been 

found on the 760-foot level. 

SULPHIDES, SELENIDES, TELLURIDES, ARSENIDES, AND 

ANTIMONIDES 

Realgar (AsS).-Small quantities of realgar are reported to 

have occurred in the Western Utah mine, but it was not observed 

by the writer. The almost complete absence of realgar and 

orpiment from the ores of the district is rather surprising, in 

view of the abundance of arsenopyrite and the fact that the two 

iron-free arsenic sulphides are generally considered to be supergene alteration products. . 

Orpiment (As2Sa).-AIso said to have been found in small 

amounts in the Western Utah mine. 

Stibnite (Sb2Sa) .-Stibnite is locally abundant on the 234-foot 

level of the U.S. mine. In one specimen, in which it was identified by W. T. Schaller, bladed crystals more than 1 inch long 

were associated with pyrite. 

Bismuthinite (BbS3).-This hypogene bismuth sulphide was 

found in the ores from the Lucy L and Wilson Consolidated 

mines, as rounded blebs in both quartz and calcite. It is 

generally either partly or completely replaced by bismutite, 

which retains the pronounced cleavage of the older mineral. 

Molybdenite (MoS2).-Molybdenite is present in many of the 

ore deposits containing silicate minerals in the gangue and was 

also noted disseminated through altered quartz monzonite in 

the vicinity of the Reaper claim. It appears to have formed 

earlier than most of the other sulphides, for it is embayed and 

replaced by chlorite in specimens from the Rube mine. In this 

mine it is extremely abundant in one portion of the ore shoot. 

Because of its presence in several of the gold ore bodies the 

mineral is thought by some to be gold-bearing. This, however, 

is not borne out by an assay made by E. T. Erickson, of the 

Geological Survey, of a specimen containing 61.6 percent of 

MoS2, in which the gold content was 0.26 ounce to the tonmuch less than is found in the shipping ore. A second assay 

was made of material containing less molybdenite, which may 

be compared with the first as follows: 

Gold Ash (ounce (percent) per ton) 

20.4 79.6 0.52 61. 6 38. 4 .26 

The gold content is thus almost exactly proportional to the 

ash content and bears no relation to the molybdenite content 

whatever. 

Galena (PbS).-Galena is found in almost all the quartzsulphide veins and limestone replacement bodies and is sparingly 

present in some of the veins with silicate minerals in the gangue. 

It has clearly formed later than arsenopyrite, pyrite, and sphalerite, but its relations to chalcopyrite are obscure, as in some 

places it appears to be later and in others to be veined by chalcopyrite. In several places it contains tiny inclusions of aikinite 

and tetrahedrite or tennanite. In specimens from the Garrison 

Monster mine it is replaced by barite (pI. 11, D). Alteration to 

anglesite, cerusite, and plumbojarosite has been wide-spread. 

Chalcocite (Cu2S) .-Small quantities of chalcocite were found 

in several places as supergene replacements of the hypogene 

sulphides. 

Sphalerite (ZnS).-The distribution of sphalerite is similar 

to that of galena. It was noted in quartz-tourmaline rock at 

the Gold Bond claim and is moderately abundant in the quartzsulphide veins and in the limestone replacement deposits. It 

replaces arsenopyrite and pyrite and is generally replaced by 

quartz and the other sulphides. Tiny rounded inclusions of 

chalcopyrite and pyrrhotite are present in most of the specimens. In several of the mines sphalerite occurs in masses 1 

inch or more across and has a nonmetallic appearance. The 

color is dark brown to black, and the cleavage is well marked. 

A thin section from the footwall of the Rube vein contained 

some dark sphalerite embedded in dolomite. Several quartz 

veinlets cut the section and in one place a veinlet impinges 

upon the sphalerite. Adjacent to the quartz the dark sulphide 

has been bleached to a colorless sphalerite whose index of 

refraction is sHghtly lower than that of the older darker 

sphalerite. 

Covellite (CuS).-Covellite was recognized in a few specimens 

as a supergene alteration product of the hypogene sulphides, 

chalcopyrite, galena, and tetrahedrite. 

Pyrrhotite (FeS\+).-Pyrrhotite is abundant only on the 900­

foot level of the Western Utah mine, where it appears to have 

taken the place of the pyrite that is found on the upper levels. 

It was also noted as inclusions in sphalerite in specimens from 

other mines. 

Bornite (CusFeS4).-Bornite was noted in small quantities in 

ores from the Alvarado, Midas, and Cane Springs mines. 

Chalcopyrite (CuFeS2).-Chalcopyrite is found in small 

amounts in all th!" different types of ore deposits except the 

carbonate and sulphate veins. It occurs both interstitial to 

other sulphides and silicate minerals and as tiny rounded 

inclusions in sphalerite. Much of it has been altered to copper 

pitch, in which remnants of the sulphide are generally abundant. 

Pyrite (FeS2).-Pyrite is found both in many of the ore 

deposits and disseminated through the altered quartz monzonite. 

It was one of the earliest sulphides to form in the ore deposits. 

It is probably later than molybdenite and has definitely replaced 

arsenopyrite but has been replaced by all the other sulphides. 

Marcasite (FeS2).-Marcasite was noted in several specimens 

from the Western Utah mine that were collected at about the 

present ground-water level. It has replaced pyrite, from which 

it may be readily distinguished in polished specimens by reason 

of its anisotropism in polarized light. 

Arsenopyrite (FeAsS).-Arsenopyrite occurs in very large 

quantities in the ores of the district, both in the quartz-sulphide 

veins and in the limestone replacement bodies, locally being 

present to the almost complete exclusion of the other sulphides. 

The arsenopyrite masses in the Western Utah and U.S. mines 

are probably the largest bodies of this mineral that have thus 

far been discovered. Where arsenopyrite has replaced limestone it appears to have formed originally as bladed radiating 

crystals (see pI. 11, A), but in most of the occurrences this 

habit has been destroyed by later fracturing and subsequent 

cementation and replacement by quartz, sericite, pyrite, and 

other sulphides. The arsenopyrite has been altered in many 

places to scorodite. Another mode of occurrence was noted on 

the 760-foot level of the Western Utah mine, at ground-water 

level, where tiny crystals of supergene arsenopyrite rest upon 

a mixture of iron oxides and scorodite. 

Calaveritef (AuT~).-Kemp 33 has described a mineral from 

the Lucy L mine that" afforded the characteristic and unmistakable test for tellurium and sweated under the blowpipe 

little beads of gold. Traces of lead and antimony were also 

indicated. The mineral is a silvery, thin-bladed brittle variety 

and would suggest a telluride or stibnite to an observer." 

SULPHOSALTS 

Jamesonite (4PbS.FeS.3Sb2S3).-Identified by M. N. Short, 

of the Geological Survey, in several polished specimens of ore 

from the U.S. mine. In the sections it appears as a bladed 

13 Kemp. J. F., Notes on Gold Hill and vicinity, Tooele County, Utah: Econ. 

Geology, vol. 13, p. 260, 1918. 
112 GOLD HILL MINING DISTRICT, UTAH 

mine~ with a galenalike color that has replaced arsenopyrite, 

pyrite, and sphalerite. No galena was found in the specimens 

containing jamesonite, and the two appear to have been 

incompatible. 

Boulangerite (Pb5Sb4S11).-Identified by Mr. Short in a specimen from the wall rock of the Rube mine. It was rather abundant as small particles in limestone. Microchemical tests by 

Mr. Short showed that it contained appreciable amounts of 

arsenic. 

Aikinite (2PbS.CuzS.BizSa).-Small amounts of the bismuthbearing sulphide aikinite were identified by Mr. Short in specimens from both the Cyclone and U.S. mines. It is associated 

with galena and appears to have formed relatively late in the 

sequence of sulphide minerals. 

Tetrahedrite and tennantite (5CuzS.2(Cu,Fe,Zn)S.2SbaSa; 

5CuzS.2(Cu,Fe,Zn)S.2AszSa).-Microchemical tests by Mr. 

Short showed that both tetrahedrite and tennantite are present 

in the ores of the district. Neither, however, is free from varying quantities of the other mineral, and it is probable that all 

gradations between the two end members could be found. No 

correlation could be made between the content of arsenic or 

antimony and the type of deposit ill which the mineral was 

found, although thc amount of material tested was not sufficient to make this conclusion a certainty. Small quantities 

of these two minerals were found in the veins having silicate 

minerals in the gangue, but they are most abundant in the 

quartz-sulphide veins and in the limestone replacement bodies, 

where they appear to be of nearly the Bame age as galena. 

Quartz veins containing tetrahedrite (or tennantite) as the chief 

sulphide are widely distributed, particularly in the vicinity of 

Royal Gulch. In these veins the minerals contain considerable 

amounts of silver, specimens from the Undine claim being said 

to run as high as 409 ounces to the ton. 

HALOIDS 

Fluorite (CaFa).-Small amounts of purple and white fluorite 

are associated with danburite on the Gold Bond claim. 

OXIDES 

Quartz (SiOz).-Quartz, as is usual, is the most abundant and 

widely distributed mineral in the ore deposits and was also 

introduced in considerable amounts in the metamorphism of 

both the sedimentary rocks and the quartz monzonite. It is 

relatively rare in the pipelike deposits; becomes more abundant 

in the veins with silicate minerals in the gangue (some of which 

contain only a few remnants of silicates surrounded by quartz) ; 

is the dominant constituent of the quartz-sulphide veins; and 

becomes progressively less abundant in the carbonate and sulphate veins. It is the chief gangue mineral, except for the 

replaced limestone, in the replacement deposits. 

Much of the quartz found associated with the ore deposits 

characterized by silicate minerals is relatively coarse-grained 

and contains numerous fluid inclusions, within which are gas 

bubbles. This habit is also found in much of the quartz that 

has replaced the quartz monzonite. In the quartz-sulphide 

veins the grain size is also relatively large, but the fluid inclusions were not observed to be so abundant. Much of the quartz 

associated with the limestone replacement bodies and composing 

the jasperoids, however, is extremely fine-grained and apparently free of the fluid inclusions. This material locally is 

associated with contemporaneous opal and barite, and much of 

it has apparently rosulted from the crystallization of a gel-like 

materiaL (See pp. 93-94.) 

In several specimens there is good evidence for the presence 

of some supergene quartz. One from the Rube mine, for example, is made up of quartz molded on pyromorphite and containing euhedral crystals of plumbojarosite. 

Chalcedony (SiOz).-All the occurrences of chalcedony are 

considered to be supergene. It was found on specimens colleeted near the outcrops of different types of ore bodies and 

occurred both as veinlets and as cavity fillings. It is locally 

associated with both opal and quartz. 

Opal (Si02.nH20).-Some opal that is definitely hypogene 

was noted in thin sections of the silicified wall rock in the U.S. 

mine. The opal occurred as irregular microscopic inclusions 

in fine-grained quartz. (See pI. 8, C.) All the other occurrences of this mineral, however, are probably supergene, and it 

is generally associated with chalcedony. Opal was locally 

abundant on the Undine claim and in the Alvarado mine, but 

elsewhere it was noted only in small quantities. 

Hematite (Fe20a).-The specular variety of hematite was 

found on the Reaper claim and in several of the veins with 

silicate gangue, notably on the Gold Bond claim, where it clearly 

replaced tourmaline (see pI. 10, B) and was replaced by 

danburite. 

Hematite is undoubtedly present in the oxidized portion of 

many of the ore bodies, but no attempt was made to distinguish 

it from goethite, and the two have been grouped together and 

described as iron oxides throughout this report. 

Spinel (MgAlz0 4).-A green isotropic mineral of high relief, 

recognized in a thin section of altered rock from the Undine 

claim, was identified as spinel. It was partly replaced by 

muscovite. 

Magnetite (FeaOt).-Small quantities of magnetite were found 

in several deposits of different types. For the most part it 

has replaced calcite that appears to have formed relatively 

late, but on the Doctor cJaim it has replaced apatite and amphibole. In much of the altered quartz monzonite it is also abundant and has apparently formed as a result of the alteration. 

It is suggested that this mineral tends to form as a result of 

the attack of the later stages of mineralizing or metamorphosing 

solutions upon earlier-formed iron-bearing minerals. On the 

Undine claim there is a considerable amount of magnetite that 

has replaced limestone. This mate'rial was reported by the 

owner of the claim to carry 0.96 ounce of gold to the ton. 

Rutile (Ti02).-In several specimens of an altered quartz 

monzonite porphyry dike from the Western Utah mine the 

original biotite was found to be altered to chlorite, sericite, calcite, and an acicular mineral that has the habit of rutile. 

Wad (amorphous brown manganese oxide of indefinite composition).-8mall black nodular masses embedded in a clay 

mineral were found in the walls of the oxidized ore bodies of 

the Western Utah mine. The material gave off chlorine when 

dissolved in hydrochloric acid, left a large insoluble residue, 

and gave a strong test for manganese, all of which indicate that 

it is probably wad. 

Copper pitch (amorphous cupric oxide of indefinite composition, usually containing silica and manganese).-Much of the 

chalcopyrite in the district has been altered to a dark-brown to 

black resinous-appearing substance that has been called copper 

pitch. Remnants of chalcopyrite are found in most of the 

material, and veinlets of chrysocolla and other oxidized copper 

minerals are generally associated with it. Some of this material 

from the Silver King claim was reported to contain 62 percent 

of copper and must therefore be composed largely of copper 

oxides. 

CARBONATES 

Calcite (CaCOa).-Calcite is a wide-spread constituent of both 

the metamorphosed rocks and the ore deposits. Considerable 

quantities are found in the pipes and veins with silicate minerals 

in the gangue, in which it appears in general to be later than 

all the silicate minerals. Its relations to quartz are contradictory, as in some places it is earlier and in others later. Locally 

it is closely associated with either magnetite or specularite and 

appears to be roughly contemporaneous with them. In most of 

the limestone replacement ore bodies and in the quartz-sulphide 

veins calcite is rare, its place being taken by ankerite or siderite. 

-
MINERALS OF THE METAMORPHOSED ROCKS AND THE ORE DEPOSITS 113 

A peculiar habit of the calcite was observed in a thin section 

from the ore of the Rube mine. A veinlet shown in the slide 

was composed of calcite crystals developed normal to the walls 

of the veinlet. These showed. an extinction inclined to the 

direction of growth, however, and the crystals must therefore 

be elongated parallel to the rhomb faces rather than the prism 

faces. 

Calcite is also wide-spread as a supergene mineral, and in 

several places it was observed associated with supergene opal 

or as well-formed crystals on iron oxides. . 

Dolomite «Ca,Mg)CO.) and ankerite (CaCO.(Mg,Fe,Mn) 

CO.).-Veinlets of pink carbonate cutting the quartz monzonite in the vicinity of the Midas and U.S. mines were found to 

have", near 1.70 and are therefore ferrodolomite, or ankerite. 

Carbonates of similar appearance were also found cutting 

several of the quartz-sulphide veins. Very large quantities of 

dolomite were also formed in the limestones of the quadrangle, 

probably during the final stages of metamorphism. In most 

places these weather to shades of brown, indicating that they 

are ferruginous. Some of the dolomitized rock near the Garrison Monster mine weathered to a deep chocolate-brown, and 

blowpipe tests showed that this material contained also some 

manganese. 

Siderite (FeCO.).-Rather large quantities of siderite are 

found on the 700- and 760-foot levels of the Western Utah mine. 

The mineral resembles closely the "dry-bone ore" of many 

mining districts, but chemical tests show that it is almost pure 

siderite and contains less than 1 percent of zinc. This siderite 

has replaced the limestone beds immediately north of the lower 

ore body of the mine and is limited downward by the groundwater level. It is clearly supergene. 

In several of the quartz-sulphide veins some hypogene siderite 

is present as thin veinlets cutting the sulphides. One of these 

veinlets in ore from the Copper Queen Midland prospect was 

tested microscopically and found to have", near 1.83, indicating 

an FeCOa content of 75 percent. It is probable that there are 

all gradations between this material and the ferrodolomite 

found at the U.S. and Midas mines. 

Large crystals of an iron-rich carbonate are also found in 

many of the carbonate veins. At the surface, however, these 

have largely weathered to iron oxides, but the preservation of 

the carbonate cleavage lines indicates their original nature. 

Smithsonite (ZnC03).-Small quantities of smithsonite are 

present in the Garrison Monster mine, and probably it can also 

be found in the oxidized ores of some of the other limestone 

replacement ore bodies. 

Cerusite (PbC03).-Small quantities of cerusite were found 

in almost all the mines containing lead ore. Most of the occurrences of this mineral are coarse-grained gray masses associated 

with galena but generally separated from it by a zone of anglesite. In the Garrison Monster mine, however, the mineral is 

in the form of the familiar "sand carbonate" and is unusually 

abundant. Locally small cream-colored terminated crystals of 

the mineral were observed. In almost all places the cerusite 

has been partly replaced by plumbojarosite. 

Malachite (CuC03.Cu(OHh).-Veinlets and small crystals of 

malachite can be found in all the mines that have copper sulphides in the hypogene ore. It is generally associated with 

azurite, chrysocolla, and copper pitch. 

Azurite (2CuCOa.Cu(OHh).-Azurite is relatively rare, but 

small quantities of it were noted as an oxidation product of 

copper sulphides at several localities. 

Bismutite (Bi20 3.COz.H,O?).-The mineral referred to bismutite is a common constituent of the ores in the Wilson Consolidated, Lucy L, and Copper Bloom claims. It has formed 

as a result of the oxidation of bismuthinite. In places the material is pseUdomorphous after the sulphide, preserving the old 

cleavage planes perfectly. This variety of the mineral is gray 

in color and is for the most part isotropic with an index of refraction greater than 2.15. It is apparently not of homogeneous 

composition, for in thin section it is streaky and of variable 

color. The gray color is possibly due to the content of tiny 

bismuthinite remnants, because in specimens in which the mineral is not pseudomorphous but is 10caUzed along fractures of 

quartz or calcite it is granular in habit and is either green or 

yellow. Some of this material has a rather high birefringence. 

No optical distinction could be made between the yellow and 

green varieties, and it is possible that the green color may be 

caused by relatively small amounts of admixed malachite. 

SILICATES 

OrthoclaslJ (KAISiaOs).-Orthoclase feldspar is one of the most 

abundant silicate minerals that were formed during the metamorphism of the quartz monzonite and of the intruded sandstones and calcareous sandstones. In the vicinity of the Wilson Consolidated mine, for example, a sandstone bed in one 

place is almost completely converted to orthoclase; and near 

the Yellow Hammer mine the quartz monzonite in several 

places was found to contain as much as 50 percent of introduced orthoclase. The mineral is also present in large amounts 

in the pipelike deposits, where single crystal faces more than 

1 foot across were observed, and in smaller quantities in many 

of the veins with silicate gangues. The color in most occurrences is pink. 

The orthoclase is generally perthitic and locally has been 

replaced by rather coarse-grained white albite, particularly in 

the pipelike deposits, but this feature has also been observed 

in the metamorphosed quartz monzonite. The mineral appears 

to h!1ve been, except for albite, one of the last of the anhydrous 

silicates to form, as it has replaced garnet, diopside, epidote, 

and amphibole. In several localities it has been replaced by 

minerals characterized by the presence of mineralizers, such as 

tourmaline and danburite, and replacement by quartz and serieite has been very common. 

Albite (NaAlSiaOs).-Noted in several specimens from the 

pipelike deposits and in the altered quartz monzonite, where 

it has replaced orthoclase. It is also present in the orthoclase 

in the form of perthitic inclusions. 

Oligoclase (albite with 10 to 30 pcreent of CaAbSi,Oa).­

Small amounts of a fine-grained mineral identified as oligoclase 

were found in altered limestone at the Alvarado mine. 

Diopside (CaMg(SiOah).-Diopside is an abundant constituent of both the metamorphosed quartz monzonite and the altered 

sedimentary rocks. Where the mineral is found in the igneous 

rock it may be readily distinguished in thin sections from the 

augite that is a sparse original constituent by the larger size of 

the crystals, their euhedral habit, and the fact that they have 

replaced all the original constituents. The mineral is particularly abundant in the altered limestones and sandstones, in 

some of which it is present to the almost complete exclusion of 

other minerals. It is relatively rare in the pipelike deposits 

but is abundant in many of the veins with silicate gangue. It 

is probable that in some occurrences the mineral is aluminous, 

as much of it has replaced garnet. It has also been observed as 

a replacement product of zoisite, epidote, and titanite. Locally 

the diopside has been replaced by amphibole, the alteration 

starting along the cleavage lines. Orthoclase has also replaced 

this pyroxene, and in the altered limestone wollastonite has 

. developed at its expense. 

Wollastonite (CaSi03).-Wollastonite is one of the most abundant silicates in the metamorphosed limestones. It occurs 

as bladed crystals that may be an inch or more in length, and 

locally it has almost completely replaced a thick limestone bed. 

It is generally associated with small quantities of garnet and 

diopside, both of which have been replaced by it. Wollastonite 

itself in many places has been altered to the mineral spadaite, 

particularly in the vicinity of the gold-bearing veins having 

silicate minerals in the gangue. The wollastonite can be readi­
114 GOLD HILL MINING 

ly distinguished optically from tremolite, which it closely resembles, by the fact that it has a transverse optic plane. A specimen from the Cane Springs mine gave the following optical 

data: a near 1.618, 'Y near 1.628, optically negative, rather 

small 2V and transverse optic plane. 

Tremolite (CaMga(SiOa).).-Tremolite was recognized microscopically in two specimens of hornfels from the Lucy L claim. 

These specimens werealtered members of the Oquirrh formation. 

The mineral was not found in any of the specimens of altered 

Ochre Mountain limestone. 

Actinolite (Ca(Mg,Feh(SiOa).) and hornblende (similar to 

actinolite but containing alumina, ferric oxide, and alkalies).­

Monoclinic amphiboles are wide-spread both in the metamorphosed sedimentary and igneous rocks and in the pipes and the 

veins having silicate minerals in the gangue. In the altered 

rocks amphibole has generally replaced diopside and locally 

garnet, a common mode of occurrence being along the cleavage 

lines of the older pyroxene. This habit is also found in many 

of the silicate veins, and in both modes of occurrence the amphibole has been partly replaced by calcite, chlorite, sericite, 

and quartz. Orthoclase, tourmaline, apatite, humite, and 

scapolite have also replaced the amphiboles. In the pipelike 

deposits the mineral is a conspicuous constituent. Here it has 

a sheaf-like habit, and individual clusters of crystals more than 

3 feet in length may be observed. Remnants of diopside have 

been found in these crystals, but it is uncertain to what extent 

these giant crystals have formed at the expense of a preexistent 

pyroxene. The same minerals have replaced the amphibole in 

the pipes as in the other occurrences. 

There appears to exist a nearly continuous gradation between 

a strongly colored hornblende and a nearly colorless (in thin 

section) variety that is probably actinolite. The darker varieties are the older and in many specimens are altered along 

cleavage planes to the lighter and nonpleochroic actinolite. 

The large crystals found in the pipe on the Reaper claim seem 

to have a composition intermediate between pargasite and 

common hornblende, as is shown by the following optical data: 

a near 1.628, 'Y near 1.645; optically negative; 2V large; pleochroism, X =pale yellow-green, Y =deep green, Z=blue-green. 

Garnet (R"aR"'2(SiO.)a).-Garnet is an abundant constituent 

both of the metamorphosed rocks and of many of the ore 

deposits. It appears to have been one of the first minerals to 

form during the postmagmatic stage of igneous activity and 

generally has been more .or less completely replaced by younger 

minerals. There is a rather wide variety of composition represented by the specimens collected, as the indices of refraction 

range from 1.777 to 1.91. Most of the specimens tested, however have n near 1.88, indicating a dominance of the andradite 

molecule. The specimen (from the Lucy L mine) whose index 

was 1.91 was associated with titanite and is probably titaniferous. 

Where the age relations of the different varieties could be 

determined, the garnet with the higher index of refraction was 

generally thought to be older. This variety also seemed to show 

fewer optical anomalies than the garnets of lower index. The 

birefringence of some of the garnets was close to 0.008, and 

those specimens that were tested were found to be optically 

positive. Twinning and zonal growth were also observed in 

many of the garnets, and skeleton crystals in calcite are rather 

abundant. 

ScapDlite group (Ca.AleSie0 2,-Na.AlaSiaOuCl).-Minerals belonging to this group were recognized microscopically in 

specimens from the Rube, Doctor, and Gold Bond claims. In 

the specimen from the Rube the mineral is associated with 

calcite and chlorite. The birefringence is about 0.030, a being 

about 1.55, and 'Y near 1.58. This indicates a composition near 

the meionite end of the series. In the other two specimens the 

scapolite has replaced garnet and hornblende. The material 

from the Doctor claim shows a well-developed prismatic cleavage, has a small optic angle, is optically negative, and has 

DISTRICT. UTAH 

a = 1.539 and 'Y = 1.549. In this occurrence, therefore, the 

composition is rather close to the marialite end member. 

V ~8uvianite (complex calcium-aluminum silicate containing 

OH and F).-Vesuvianite was noted in thin sections of the gold 

ore from the Midas and Cane Springs mines. In the Cane 

Springs specimen it occurred as large crystals in association with 

zoisite, from which it was distinguished by its uniaxial negative 

character. In this occurrence it was older than diopside and 

wollastonite, having been partly replaced by these minerals. 

Zircon (ZrSiO.).-Abundant crystals of zircon were noted 

under the microscope in several specimens of metamorphosed 

rocks and also in a specimen from the pipe on the Reaper claim. 

They showed the simple combination of prism and pyramid 

faces, were optically positive, and had a moderately strong 

birefringence. 

Danburite (CaB2(Si04h).-Flesh-colored massive danburite 

is abundant on the Gold Bond claim, where it was found in 

veins as irregular or lenticular masses that were more than ] 

foot across. The mineral had replaced specularite and was 

itself partly replaced by calcite. The following optical data 

were determined by W. T. Schaller and E. P. Henderson: 

Orthorhombic, optically positive, 2E large, a=1.627, j$"=1.629, 

'Y=1.632. 

AndaZusite (AI,SiOs).-Andalusite was noted in several specimens taken from the Manning Canyon formation near the 

quartz monzonite stock. An extended description of the occurrence of the mineral near the Cane Springs mine has been given 

by Kemp.84 

Zoisite (Ca2(AIOH)AI2(SiO.)a).-Greenish-brown zoisite was 

recognized in several specimens of altered limestone and also 

in the gold ores from the Cane Springs, Rube, and Bonnemort 

claims. It is locally associated with vesuvianite. Where it 

has formed in calcite, euhedral crystals a quarter of an inch in 

diameter may be found. In other specimens the mineral has 

formed at the expense of garnet and ha.. itself been replaced by 

diopside, wollastonite, spadaite, and chlorite. The index of 

refraction near 1.72, low birefringence, biaxial positive character, 

parallel extinction, and small optic angle are characteristic. 

Clinozoillite (Ca2(AIOH) AI2 (SiO.)a) .-Brownish-green radiating fibrous crystals of clinozoisite were found in a specimen of 

metamorphosed limestone near the Frankie claim. 

Epidote (HCa2(Al,FehSi30 13).-Two varieties of epidote were 

recognized in the specimens collected. A normal green epidote 

was found in the pipe on the Doctor claim and in the wall rock 

of the silicate vein on the Frankie claim. The other variety was 

in the form of black euhedral crystals 3 millimeters in maximum 

length in the tungsten-bearing ores on the Reaper, Yellow 

Hammer, and Lucy L claims and in the wall rock of the Gold 

Bond claim. The mineral had the following optical properties: 

Biaxial negative; 2V large; strong dispersion (r> v on material 

from the Lucy Land r<v on specimens from the Gold Bond); 

a near 1.745, 'Y near 1.772; twinned and strongly zoned; notably 

pleochroic, X=pale yellow to nearly colorless, Z=deep greenish 

brown to nearly opaque. The pleochroism is unlike that 

reported for other epidotes and is similar to that of allanite, 

but the indices are much too high for allanite. These crystals 

were among the first minerals to form in the deposits in which 

they are found, being associated with titanite and garnet. It 

is possible that the unusual properties of the mineral may be 

due to the presence of titanium, as the garnet in some of these 

deposits has properties suggesting that they also are titaniferous. 

Axinite (a borosilicttte of aluminum and calcium).-Axinite 

was found by Butler 311 at several localities. It was not recognized by the writer in any of the specimens collected by him, 

.. Kemp, J. F., Notes on Gold Rill and vicinity, Tooele County. Utah: Econ. 

Geology, vol. 13, pp. 254-257. 1918. 

31 Butler. B. S., Ore deposits or Utah: U.S. Geol. Survey Prof. Paper 111, p. 479, 

1920. 
115 

r 

MINERALS OF THE METAMORPHOSED ROCKS AND THE ORE DEPOSITS 

but its presence in Butler's specimens was checked by optical 

determinations. 

Humile group (Mg(F,0H)2.MgSiO.Mg(F.OH2).Mgl(SiO~)!).­

Considerable quantities of a pale flesh-colored mineral thought 

to be humite were found on the Calaveras and Frankie 

claims. The mineral has replaced garnet, tourmaline, orthoclase, and other silicates and appears to have been the last 

silicate to form. It has been extensively replaced by calcite 

and some quartz. A similar mineral was recognized in the 

altered wall rock of the lower ore body in the Western Utah 

mine. The. following optical data were determined: Biaxial 

positive, large axial angle, parallel extinction, 4 near 1.619, 

'Y near 1.652. 

Calamine (H2ZnSiO~).-Sman crystals of a mineral determined optic/tlly and chemically as calamine were found in the 

oxidized ore of the Garrison Monster mine. It was associated 

with clay minerals and iron oxides. 

Tourmaline (complex silicate of boron and aluminum).­

Tourmaline is of wide-spread occurrence in the district. It 

has been no.ted along joints in the quartz monzonite, as a constituent of the metamorphosed rocks (particularly in the Manning Canyon formation, in which it forms stubby black crystals 

as much as an inch in length), and as a common mineral in 

many of the ore deposits with silicate minerals in the gangue. 

It was formed relatively late, for the only minerals noted as 

having replaced it are danburite, specularite, quartz, sericite, 

and calcite. The tourmaline is generally found in sheafs of 

acicular crystals, which, on the Reaper claim, reach a length 

of several inches. In these occurrences the color of the mineral 

is a brilliant black, and under the microscope its indices were 

found to be E=1.655 and ",=1.695, and the pleochroism pale 

yellow-green to almost opaque. In several places the black 

variety was replaced by a fine-grained aggregate of sericite, 

calcite, quartz, and blue tourmaline, in which the pleochroism 

was ",=pale blue-green and E=colorless. 

Muscovite (H2KA1a(SiO.h).-Muscovite, particularly the finegrained variety sericite, is widely distributed in both the altered 

sedimentary and igneous rocks and in all types of the ore 

deposits. The mineral formed relatively late and has replaced 

all the other silicate minerals. It is generally associated with 

chlorite, quartz, and calcite. It is probably also in part at least 

contemporaneous with many of the metallic minerals, although 

in the Western Utah mine it has clearly replaced arsenopyrite. 

It occurs with quartz in all the gold ores of the district and is 

present in the wall rocks of the quartz-sulphide veins. The 

more coarsely crystalline form known as muscovite was recognized'in several of the ore deposits with silicate minerals in the 

gangue. 

Biotite «H,Kh(Mg,FehAI2 (SiO.h).-Biotite is an abundant 

constituent of the metamorphosed shales of the Manning 

Canyon formation and is associated with quartz and andalusite. 

It was also observed in small quantities associated with muscovite in the pipe on the Reaper claim and in vein material from 

the Gold Bond claim. 

Chlorite group (H8M~AhSi30Is).-Two varieties of chlorite 

were distinguished. The more .abundant variety is nearly black 

when viewed in the mass and is green and pleochroic under the 

microscope. Much of it is either isotropic or has an extremely 

low birefringence. This variety is a wide-spread constituent of 

the metamorphosed rocks, particularly the quartz monzonite, 

and is generally found in association with sericite and quartz, 

having replaced the older minerals. It is also abundant in many 

of the ore deposits that contain silicate minerals. The second 

variety is colorless in thin section and has an appreciable birefringence. Material from the Rube mine was biaxial positive 

and had the following indices of refraction: 4= 1.549, 'Y= 1.553. 

The relations of this variety to the green chlorite are not known, 

Jefferisi!e (complex magnesium-aluminum silicate).-The 

vermiculite known as jefferisite was found in several places in 

the low-lying region north and west of the town of Clifton, 

either in the limestone at the quartz monzonite contact or in 

some of the silicate veins near the contact. In the veins it was 

associated at several places with magnetite. The mineral 

occurred as dull-green plates that were as much as 1~ inches 

in diameter in the occilrrences in limestone. fJ and 'Y were close 

to 1.575, and C. S. Ross determined 2V to be about 110. 

Talc (H2Mg3(Si03)•.)~-Talc was identified by C. S. Ross in a 

thin section of ore from the Rube mine, in which it was present 

as fibrous fine-grained patches associated with calcite in muscovite. 

Spadaite (MgO.Si02.2H20).-The unusual mineral spadaite 36 

was found to be relatively abundant in the gold ores of the 

Alvarado and Cane Springs mines and was also recognized ill a 

specimen of ore from the Midas mine and in metamorphosed 

limestone near the Monocco claim. In all the occurrences it 

has replaced wollastonite (see pI. 8, B) and has itself been 

locally replaced by quartz. It occurs as a fine-grained aggregate 

of fibers and in mass has a yellowish or pinkish color. The 

following analysis was made on a specimen from the Cane 

Springs mille that was largely composed of this mineral: 

Analysis of spadaite from Gold Hill, Utah 

[W. T. SchaJIer, analystI 

Insoluble_ _ ____________________ 8.68 

Si02 soluble in Na2C03_ _______________.41 Si0 __________________________________ 43.28 2 

Fe203_________________________________ .22 

FeO____________________ _____________ .27 

CaO_ _ _ ___ __ __ _____ ____ ______ __ _ 1. 58 

MgO_________________________________ 24. 72 

H 0- ___________ _ __________________ 10.36 

H20+ __ _______________ ______ _ ________ 10. 51 2 

100. 03 

Deducting from this the impurities-8.68 percent insoluble 

residue (diopside and garnet), 3.27 percent wollastonite (based 

on the CaO percentage), 0.41 percent opaline silica (soluble in 

10 percent Na2COa solution), 10.36 percent water at 1100 , and 

0.22 percent Fe20a as limonite-and recalculating to 100 percent gives the following figures for the composition of the mineral, with which may be compared the analysis of the original 

material from Italy: 

Italy 

66.00 

.66 

30.67 

11.34 

.66 

99.33 

Clay minerals (hydrated aluminum silicates).-Clay minerals 

are found in the vicinity of many of the oxidized ore deposits 

in the district. In many places they occur as a sort of casing to 

the oxidized ore, a relation that is well illustrated by the body 

of clay that surrounds the lower portion of the gold-bearing 

quartz lens on the Lucy L claim. These minerals are commonly 

associated with iron oxides, and in one place they enclose masses 

of the mineral wad. They have apparently been formed as a 

result of the reaction between the sulphuric acid generated by the 

oxidation of the sulphides in the ore body and the silicate minerals in the wall rocks. At least three varieties of clay minerals 

but it is probably somewhat later, as it is a constituent of ae Schaller, W. T., and Nolan, T. B., An ()()Cllrrence ofspadaite at Gold HUl, Utah: 

jasperoid in several localities, particularly in the U.S. mine. Am. MIIlel'RlogIst, vol. 16, pp. 231-236. 1931. 
116 GOLD HILL MINING DISTRICT, UTAH 

were recognized under the microscope, and in many places these 

may occur together. One variety has an index of refraction 

near 1.57 and a low birefringence--properties that correspond to 

those of the kaolinite group; another has indices lower than 

canada balsam and a distinctly higher birefringence than the first 

variety and is possibly related to beidellite. The third variety 

is isotropic, and different specimens have indices ranging from 

1.51 to 1.55. This variety has been referred to as halloysite. 

Nontronite (F~0a.3Si02.2H20).-Nontronite, which is isomorphous with the clay mineral beidellite, was found as a yellowgreen powdery coating on ore specimens from several mines in 

the district. 

Chrysocolla (CuSiOa.2H20).-Chrysocolla was noted in 

specimens from several mines and prospects as thirl veinlets 

cutting copper pitch or as coatings on ore or wall rock. In 

the Western Utah extension mine it was in turn coated by the 

Msenic-bearing conichalcite. 

TITANOSILICATES 

Titanite (CaTiSi05).-Titanite was found to be an abundant 

constituent of some of the specimens of metamorphosed quartz 

monzonite and was also found in the ore of several of the tungsten-bearing pipes and veins. It occurs as swarms of small 

euhedral crystals from 0.1 to 1 millimeter long and is in many 

places associated with epidote and diopside. The diopside has 

locally replaced the titanite, and danburite, specularite, and 

orthoclase have also been noted as being distinctly later. 

PHOSPHATES, ARSENATES, VANADATES, AND ANTIMONATES 

Apatite (Ca5(F,Cl) (P04)a) .-Considerable quantities of a pale 

flesh-colored or yellowish apatite are present in the tungsten 

pipes north of Clifton. In these occurrences the mineral tends 

to have crystal outlines, and crystals nearly an inch across are 

not uncommon. It is normally embedded in amphibole and 

clearly has replaced that mineral. On the Doctor claim it has 

been replaced by magnetite. Flakes of iron oxide along irregular cracks in the mineral in places give it a distinctly pinkish 

color. On the Copper Bloom claim the ore contains numerous 

small crystals of yellow or greenish crystals of apatite that are 

about an eighth of an inch in diameter. These appear to have 

replaced tourmaline. The mineral has also been recognized 

microscopically in some of the gold-bismuth ore. 

Pyromorphite (Pb5Cl(POv3).-Pyromorphite was identified by 

E. P. Henderson in a thin section of oxidized ore from the Rube 

mine. It occurred both in large prismatic crystals and in massive aggregates coated by supergene quartz and was partly 

replaced by plumbojarosite. 

Mimetite (Pb5Cl(As04)a).-Creamy-white crystals of mimetite were identified chemically by Mr. Henderson in oxidized 

ore from the Western Utah mine. He also recognized the mineral in oxidized ore from the Red Jacket claim, but at this 

locality the color was greenish. 

Olivenite (Cu2(OH)As04).-Deep olive-green olivenite was 

recognized by W. T. Schaller and W. F. Foshag and was also 

identified by the writer in oxidized ore from the Western Utah 

Extension mine, where it was coated or partly replaced by conichalcite. Under the microscope the mineral was seen to have a 

high birefringence and 2V near 90°. fJ is a little higher than 1.80. 

Adamite (Zn2(OH)As04).-Adamite was identified chemically 

by Mr. Henderson in oxidized ore from the Western Utah mine. 

It occurred as tiny white prisms with scorodite and iron oxides. 

Under the microscope the indices were seen to be near 1.73. 

The mineral has a prismatic cleavage, parallel extinction, and 

is optically positive. 

Descloizite «Pb,Znh(OH) VO.) .-Small crystals of descloizite 

were determined by W. T. Schaller in oxidized lead ore from the 

New Baltimore claim. 

Olinoclasite (CuSAs20S.3Cu(OH)2).-Clinoclasite was identified by W. F. Foshag in oxidized ore from the upper ore body of 

the Western Utah mine. 

Arseniosiderite (CII.3Fe(AsO~)a,3Fe(OH)3).-Several specimens 

of arsenic ore from the Western Utah mine were found to contain considerable quantities of arseniosiderite. In some specimens it appears to have formed. at the expense of massive scoroditej in several, however, it is not associated with scorodite 

but contains blebs of jarosite or is coated with beudantite and 

mimetite. The mineral is found in aggregates of fine-grained, 

rather fibrous crystals that have a lustrous pale greenish-brown 

color and a reddish streak. Specimens gave qualitative tests 

for calcium, iron, and the arsenate radicle. The following 

optical data were also determined: Indices of refraction between 

1.82 and 1.88, birefringence moderate, slightly pleochroic in 

reddish browns. 

Ferrisymplesite1 (3Fe20a.2As,Ois.16H20) .-A bright-yellow 

powdery mineral coating a mixture of quartz and arsenopyrite 

from the U.S. mine was submitted to W. T. Schaller for identification. He writes, "The yellow coating contains ferric iron 

and arsenate with some lime and sulphate (probably due to 

gypsum). There is no uranium present. Ammonia does not 

turn it red, like pharmacosiderite. It may be related to ferrisymplesite,37 which has the formula 3Fe20a.2As20s.16H20. 

Refractive indices 1.650 ±. Strong birefringence." 

Scorodite (FeAsO•.2H20).-Scorodite is by far the most abundant oxidation product of the large masses of arsenopyrite that 

occur in the district. The largest quantities of the mineral are 

found in the Western Utah mine, in which the upper and middle 

ore bodies are composed almost completely of this mineral and 

also the lower ore body down to the 700-foot level. The amount 

in the U.S. mine is considerably less, because here oxidation 

extends only locally below the adit level. Scorodite is also 

present in the oxidized portions of all the other ore bodies in 

which arsenopyrite is one of the hypogene sulphides. The 

material that has been called scorodite varies widely in color and 

appearance. (See pp. 105-106 and pI. 12, A, B.) Most of it 

is extremely fine grained and breaks with a conchoidal fracture. 

Thin sections of such specimens show that it is composed of an 

isotropic streaked mineral that may be either white or brownish. 

The isotropic mineral is in many places in sharp contact with 

crystalline scorodite, much of which, however, is so fine grained 

that it has an appearance not unlike that of the isotropic substance. In most places this crystalline scorodite contains an 

admixed iron oxide, and the color of the mixture is brown of 

various shades, depending upon the amount of iron present. 

Where the iron oxides are absent the scorodite is deep green. 

In a few places the size of grain increases and crystals as much 

as an eighth of an inch in diameter may be found. A specimen 

obtained just above the 150-foot level of the Western Utah 

mine was composed almost entirely of crystalline material 

from which the following optical data were determined: Biaxial positive, moderate 2V, dispersion r>v; indices, a= L788, 

fJ=1.797, ,),=1.818. Foshag, Berman, and Doggett 38 have 

recently studied the crystalline scorodite from the Western Utah 

mine and give the following optical properties: 

"The mineral is optically negative S9 j 2V=54°±5°. r>v 

(easily perceived in the interference figure but not sufficiently 

strong to measure on the Fedorow stage). The indices of refraction for yellow light, as determined by the Merwin dispersion 

method, are as follows: a=1.784±0.001, fJ= 1.796± 0.002, 

-y=1.814±0.00l. Dispersion F-C=0.03±0.005." 

"Walker, T. L., and Parsons, A. L., The arsenate of cobalt, nickel, and iron observed in the silver·bearing veins at Cobalt, Ontario: Toronto Univ. StudIes, Geol. 

IIOr., no. 17, p. 17, 1924. 

" Foshag, W. F., Berman, Harry, and Doggett, R. A., Scorodlte from Gold Hill. 

Tooele County, Utah: Am. MineralogIst. vol. 15, pp. 300-391, 1930. 

39 Obviously II misprint for posltlve.-T. B. N. 
MINERALS OF THE METAMORPHOSED ROCKS AND THE ORE DEPOSITS 117 

Foshag's analysis of the mineral is as follows: 

Analysis of scorodite from Gold Hill, Utah (U.S.N.M. 94821) 

Fe 0a_______________________________ _ 2 34. 13 AI 0 _______________________________ _ 2 a None 

FeO________________________________ _ .84 CaO________________________________ _ .38 

MgO _______________________________ _ .01 

AS 0 _______________________________ _ 2 6 48. 42 

PZ None 0 6--------------------------------­ H2

0+ --- ____ ---- __________________ -- 15.73 

H 20 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --- .23 

Insoluble ___________________________ _ .42 

100. 14 

Conichalcite «Cu,CahAs20S.(Cu,Ca) (OHMlH20).-The basic 

copper arsenate conichalcite appears to be the most widespread of the several green copper arsenates found in the 

oxidized ores of the district. It was recognized in specimens 

from the Western Utah and Western Utah Extension mines, 

in both of which it occurs chiefly as a mammillary coating on 

scorodite, iron oxides, or other minerals. It was also observed 

in one specimen as a replacement product of the olivenite. The 

mineral has a distinctly fibrous habit and under the microscope 

was seen to be nonpleochroic, with parallel extinction, with 

the slow ray parallel to the elongation, and optically positive. 

It is either uniaxial or has a very small optic angle and has a 

(or w) near 1.76 and 'Y (or .) near 1.80. 

Pharmacosiderite (6FeAsO,.2Fe(OH)a.12H20).-Heikes '0 writes 

that the ore of the Western Utah mine is a "cellular mass 

of scorodite and brownish oxidized mineral (pharmacosiderite?)." 

Beudantite (3Fe20a.2PbO.2S0a.As206.6HaO) .-A j~rositelike 

mineral containing lead and arsenic is present in large quantities in the district, particularly in the Western Utah mine. 

It is probable that there are all gradations between pure plumbojarosite and beudantite. The mineral Is in all places very 

fine grained and appears to have been one of thc.mostrecent 

of the oxidation products to form. The color is generally 

yellow-brown, but one specimen was greenish. Under the 

microscope the mineral is seen to occur in well-formed crystals, 

either as flat hexagonal plates or as positive and negative rhombs 

combined with the basal face. 

SULPHATES, CHROMATES, AND TELLURATES 

Barite (BaSO,).-Barite is present in small ql.lantities in 

almost all the jasperoid masses. It has also been recognized 

in several of the quartz-tetrahedrite veins. The mineral is 

particularly abundant in the Garrison Monster mine, where it 

is found in the vein itself and in the limestone wall rock. At 

this place it is later than the sulphide minerals and locally has 

replaced them. Large quantities of barite are also present in 

the barite veins and limestone replacement bodies at several 

places in the quadrangle. In these the barite appears to have 

been the only mineral introduced. 

Anglesite (PbSO,).--,-,-Anglesite was noted in almost all the 

lead-bearing ore deposits of the quadrangle, It was developed 

as the first stage in the oxidation of galena and generally borders and veins the sulphide. It has itself been replaced by 

cerusfte and plumbojarosite. In the Rube mine native- gold 

was observed embedded in anglesite in several specimens. 

Gypsum (CaSO,.2H20) .-Considerable quantities of crystalline gypsum were found at the ground-water level in both the 

U.S. and Western Utah mines. 

to Heikes, V. C., Arsenic In 1923: U.S. Geol. Survey MineraI Resources, 1923, 

pt. 1, p. 166, 1924. 

Chalcanthite (CuSO,.5H20) .-Blue and greenish-blue glassy 

crystals of chalcanthite half an inch in maximum length were 

found embedded in copper pitch on the bottom level of the 

Alvarado mine. The mineral was also recognized in the Cyclone 

mine, where it occurred on the walls of the drift and had obviously formed since the workings had been driven. 

Siderotil (FeSO,.5HaO) .-Siderotil is associated with chalcanthite and copper pitch in the Alvarado mine. It is a palegreen fibrous fine-grained mineral that occurs in areas of rectangular outline. These areas, however, are cut by numerous 

desiccation cracks, and the mineral is probably pseudomorphous 

after melanterite. It is soluble in water and gives qualitative 

tests for iron and sulphate. The indices of refraction are a 

near 1.52, 'Y ncar 1.54. 

Jarosite (K2FeG(OH)12(SO,),).-Because of the difficulty in 

distinguishing members of the jarosite and related groups from 

one another except by chemical tests, it is uncertain how widespread the occurrence of pure jarosite is in the oxidized ores of 

the district. Most of the specimens tested contained lead, but 

several were lead-free and gave flame tests for potassium, so 

that jarosite is definitely present in at least some of the ores. 

One specimen from the U.S. mine contained no lead but did 

contain arsenic, so that there is probably a series comparable 

to the plumbojarosite-beudantite series in the lead-free minerals. 

Natrojarosite (Na2Fe6(OHha(SO,),).-A specimen of a jarosite 

mineral from the Western Utah mine was found on testing to be 

free from lead and potassium and gave a strong flame test for 

sodium. It is probably natrojarosite. 

Plumbojarosite (PbFe6(OH) 12 (SO,),) .-Plumbojarosite or gradations between it and its arsenic-bearing analog, beudantite, 

is probably the most abundant lead mineral in the oxidized ore 

of the district. It is found in all the lead-bearing veins and 

is clearly later than either anglesite or cerusite, and in many 

places it also veins and coats iron oxides. In the Rube mine 

the mineral is embedded in supergene quartz. Variations in 

the arsenic content may be found in the same mine. In the 

Western Utah mine, for example, a specimen from the south 

end of the open cut contained almost no arsenic, and another 

less than 100 feet away contained a considerable percentage of 

it. The mineral is found in various shades of brown and is 

always very fine-grained. At the Monocco mine lessees shoveled all run of mine ore through a screen and shipped the screenings, which were composed largely of plumbojarosite. Like 

beudantite, the mineral is seen under the microscope to be in 

the form of well-developed crystals, either as the common flat 

hexagonal plates or in crystals made up of combinations of 

rhomb faces and the base. 

TUNG STATES AND MOLYBDATES 

Wolframite «Fe,Mn)WO,).-Hess found wolframite on the 

Keno claim, according to his unpublished notes. 

Scheelite (CaWO,) .-Only s~all quantities of scheelite can 

now be found in the district, but it has been recognized in several 

of the pipes and veins having silicate minerals in the gangue. 

The numerous large crystals on the Reaper claim described by 

Butler" are no longer there, having been mined during the 

World War when the demand for tungsten was at its height. 

Similar deposits nearby have also been almost completely 

stripped of the visible scheelite. In the specimens collected by 

the writer from the Wilson Consolidated, Reaper, Centennial, 

Yellow Hammer, and Copper Bloom claims the scheelite 

appears as a dull-white or yellowish mineral of rather greasy 

appearance and in places is very similar to the apatite that also 

occurs in these deposits. The two may be readily distinguished 

11 Butler, B. S., Ore deposits of Utah: U.S. Gaol. Survey Prof. Paper 111, p. 476. 

1920. 
118 GOLD HILL MINING DISTRICT, UTAH 

under the microscope, however, by reason of the high index of 

refraction of the scheelite, as well as its higher birefringence. 

In all the specimens studied the scheelite was seen to have formed 

relatively early, and it has been replaced in different specimens 

by amphibole, tourmaline, chlorite, sericite, quartz, and 

sulphides. 

CupTotungstite (CuW04).-Hess recognized cuprotungstite 

on the Keno claim, according to his unpublished notes. 

Powellite (Ca(Mo,W)04).-Powellite was found as white 

porcelaneous pseudomorphs after molybdenite at several 

places on the Reaper claim. 

Stolzite (PbW04) .-The stolzite was questionably identified 

by Butler 42 in a specimen from the Wilson Consolidated mine. 

Wulfenite (PbMoO.).--Small brilliant orange-colored crystals 

of wulfenite are present in the oxidized ore of several of the 

quartz-sulphide veins north and northwest of Clifton, such as 

the vein on the Red Jacket claim, in which it is associated with 

mimetite. 

MINES AND PROSPECTS 

The mines and prospects in the quadrangle are 

included in the Clifton and Willow Springs mining 

districts. The Clifton district is by far the more 

productive of the two. Its outlines are not well 

defined but are approximately those of the area shown 

on plate 2. The boundary between the two districts 

has never been fixed, so far as known, but in practice· 

the line of Overland Canyon is used to separate them. 

The Willow Springs district extends for some distance 

beyond the southern boundary of the quadrangle, . 

but the prospects outside of the quadrangle were not· 

examined during this survey. 

The descriptions of individual mines and prospects 

in the Clifton district are arranged in the same order 

as that in which the different types of ore bodies were 

described. Several of the mines contain more than 

one type of deposit however, and for such mines, the 

more productive type was used to determine the 

position of the description. 

It is probable that the names here used for some of 

the prospects no longer apply, because each year many 

of the unpatented claims are allowed to lapse by . 

omission of the required assessment work. Many of 

these claims are then restaked under new names. 

CLIFTON DISTRICT 

HISTORY OF MINING AND PRODUCTION 

The following account of the early history of the 

Clifton district is quoted from Heikes: 43 

The first discovery of mineral is said to have been made in 

1858, but the hostility of the Indians retarded development 

until 1869, when the first mining operations were begun and the 

district was organized (on October 18). Huntley 44 reviews the 

conditions in November 1880 as follows: 

itA smelter was built in 1871 and was moved in 1876 to a spot 

6 miles distant by the St. Louis Consolidated Co. Probably 

150 tons of bullion were produced. * * * About 50 claims, 

.. Butler, B. S., Ore deposits of Utah: U.S. Gool. Survey Prof. Paper 111, p. 482, 

1920. 

.. Heikes, V. C., Ore deposits of Utah: U.S. Geol. Survey Prof. Paper Ill, p. 475, 

1920. 

.. Precious metals: Tenth Census U.S., vol. 13, p. 4ll6, 1885. 

of over 500 located, are still worked occasionally. Little has been 

done since 1877." 

The smelter built in 1871 is reported by an old resident .1 and 

mine owner of the district to have been a stack furnace 

operated with three blacksmith bellows. Three tons of lead 

bullion represented the results of the first operations. In 1872 

Gilbertson & Berry's furnace was built at Clifton to treat the 

ores from the Gilbertson mine at Gold Hill. About 30 tons of 

lead bullion .6 shipped to Salt Lake averaged $93 in silver per 

ton. A few years later this furnace was moved to Gold Hill 

by J. W. Harker. The crude ore smelted carried about $4 in 

gold, 30 ounces of silver per ton, and 25 to 30 percent of lead. 

Activity in mining did not again assume importance until 1892, 

when a. mill was put in operation at Gold HilL The ores treated 

were from the Cane Springs, Alvarado, and Gold Hill claims, 

which were credited with a total gold production of $207,986 

from September 1892 to November 1895. Of this total probably 

half the ore and more than three-fifths of the gold came from 

the Alvarado mine. No complete record of the amount of 

ore handled exists, but a partial record shows 9,475 tons of ore 

milled from August 1892 to May 1894, assaying $14 per ton 

and yielding $97,393, or $10.28 per ton. At the same rate, the 

total ore worked was about 19,000 tons.n The gold produced 

was very pure, some of it 0.946 fine. 

The Midas property is about 3 miles southeast of Clifton. 

In 1896 and prior to that year 95 tons of ore averaging $56 in 

gold and a trace in silver per ton were treated at the Cane 

Springs mill and shipped to the smelter. In 1902 a 40-ton 

cyanide mill was c;onstructed and treated 622 tons with a reported saving of $15 per ton in gold. In 1904 the mill was 

operated again, but the results were unfavorable, and the 

property was practically abandoned. 

In 1906 the Western Utah Copper Co. acquired the 

principal properties on Gold Hill, and during the 

succeeding 10 years this company confined its efforts 

to development work in anticipation of the construction of a branch line of the Western Pacific Railroad 

from Wendover. In this period there was no production from the district except for small lots from a few 

prospects. 

Construction of the long awaited branch railroad 

was finally started in 1916 and completed in 1917; in 

that year the production of the district amounted to 

33,960 tons of ore valued at $705,957. Over half of 

this came from the Western Utah Copper Co.'s Gold 

Hill mine. From this initial production shipments 

gradually decliIied, except for a slight J,ise in 1920, 

until in 1922 o~y 211 tons of ore was $ipped. In 

1923 and 1924, however, a demand for arsenic, which 

had been discovered in large quantities at the Gold 

Hill mine, caused a temporary revival. The collapse 

of the arsenic market in 1925 caused a curtailment of 

activities, and the production for the following year 

declined sharply. Since 1926 the production has been 

made up chiefly of small and intermittent shipments. 

The following table shows the production of gold, 

silver, copper, lead, and zinc in the district from 1901 

to 1932, the figures being obtained from the annual 

" Dunyon, Isaac, Salt Lake City, personal Interview • 


" Fabian BenthQIll, Resources of Utah, 1872, p. 16. Salt Lake City, Utah, 1873. 


(1 Daggett, Ellsworth, unpubllllhed mining notes. 


-----------._._-­

r 

------------ ----------------------

- -- - -- - ---

------------ ---- -----

---------

----------

----------

----------

-- ------- ----------

----------

----------

----------

----------

----------

---------

---------- ----------

MINES AND 

statistical reports by V. C. Heikes (1905-25) and 

C. N. Gerry (1926-32) in Mineral Resources of the 

United States. It is not complete for the years before 

1914, but the omissions are probably of no great 

importance. There have been in addition small shipments of tungsten, bismuth, and molybdenum ore, 

but nothing is known as to their monetary value. 

PROSPECTS 119 

The production of arsenic ore is also uncertain, for 

most of it was shipped on the basis of a flat rate 

per ton. Rough estimates, however, indicate that the 

arsenic ore contained about 9,000 tons of metallic 

arsenic, which, when converted to AS20 5, would have 

had a value of abo1,lt $2,500,000, on the basis of the 

average prices during the years of production. 

Gold, silver, copper, lead, and zinc produced in the Clifton district, 1901-32 

Year lore (tons) Gold (Ollll.C!lS) ISilver (ounces) Copper (pounds) 

--------..-----------------------------1----­

1901________________________________ 18 ___________ _ 68 1902_____________ _____ _ _________ 651 48220 641 1903_______________________________________________ ._. ___ _ (a) 1904________________________________ 1,660 969.00 92 

(a) 

<a) - - }4-- - - - - - - ­ i8gg====================================================== <al 

(aJ 1909____________________________________________________ _ t~g~====================================================== (aJ 1910_____________________________________________________ _ 

~~~i==================:=======:==========:==:= 1913________________________________________ _ -----------­ _=========== 1914________________________________

1915____________________ ___________ 1916_______________________________ 

1917_______________ -- -------------1 1918________________________________ 

1919________________________________

1920__________________ ._____________ 192L__________ ____________________ 1922________________________________ 

1923________________________________

1924____ _____ ___ ___ ____ __ _ _ _ _ _ __ _ _ __ 1925________________________________ 

1926________________________________ 1927_____ __________________________ 

1928________________________________ 

1929________________________________

1930____ _ _ __ _ _ _ __ __ _ _ __ ____ ___ ____ __ 1931._______________________________ 

1932________________________________ 

66c 5~25 

16 5.21 

67 8.90 

33,960 564.31 19,714 449.56 

14,257 233.89 39,656 77.43 

11,627 266.09 

211 27& 61 

13,237860.60

33, 094 511. 05 

13,721 808.90 

1,382 1,129.20 526 926.04 

195 3.24 

415 480.27 

I, 009 77. 84 

2,259 1,142.40 

2,915 2,361. 00 

'. Not recorded. 

MINES AND PROSPECTS 

PIPELIKE DEPOSITS 

REAPER 

The Reaper group of claims, owned by the Seminole 

Copper Co. and managed by the Wilson Brothers, of 

Salt Lake City, is about three-quarters of a mile west 

of north from Clifton. The group appears to have 

made the largest production of all the several tungsten 

prospects in the Clifton district, but the total amount 

is not known. It must have been very much less than 

100 tons of 60 percent ore, for that figure represents 

the total production from Utah during the period 

1914-18 and includes ore shipped from several other 

districts. 

The ore body was developed by a vertical shaft 

105 feet deep, from which were driven 2 levels, 

one at the 'bottom of the shaft and one 56 feet 

higher. The upper level was driven beneath the outcrop, from which the ore body was removed by means 

of an open stope to the surface (fig. 13). There are 

in addition several other shallow prospect holes on 

(aJ 


(al 


(aJ 


(a) 

146 5,054

149 1, 470 

645 10,547

161,204 1,894,731 

97, 241 828,658 

53, 706 194,476 

89,578 92,913

23,208 3, 194 

2,974 4,521 

41, 195 33,040

147,786 3,615 

111,372 54,459

13,772 13,826 

4,413 2,396 

1,578 2,995

I, 229 40,001 

3, 704 47,885

2,384 22,046 

I, 207 6,473 

Lead (pounds) Zinc (pounds) Value 

--~--.;-.---!----

174,084 

666 $69 

6,000 10,554 

20,085 

- - - -- -- _ ... --­ - - - - - - - - - -

1,924 ---------... 4, 782 

513,929 

1,204,472 ... --------­ 778, 869 

I, OW, 833 

336,292 

16,524 

291, 554 

1,840,453 

1,960,853

267,083 2, 243 

53, 701 14, 754 

50,233

1,237 1---------­ 280,480 

458, 723 

1,936

530 

3,532

705,957 

396, 730 

142,439 

197,204

44, 253 

10,252 

76,836

257, 290 

272, 339 

55,416 

26,286 

4,355

17,703 

23, 284 

43,285 

the property. Those adjacent to the main workings 

are shown in figure 14. 

The country rock of the vicinity is quartz monzonite. 

Where unaltered, this appears to be normal mineralogically but of rather finer grain than the average specimens. Locally the rock has a distinctly pink color, 

due to the introduction of feldspar. A green pyroxene 

has also replaced the rock in some places. In a specimen of wall rock from the 100-foot level the original 

plagioclase of the quartz monzonite had been partly 

altered to albite and calcite, and the dark minerals 

had been completely replaced by calcite, sericite, and 

iron oxides. Some orthoclase has been introduced into 

the rock, giving it a distinctly pink color in the hand 

specimen, and in addition there are several areas of 

clear, glassy quartz and black tourmaline. Locally 

also veinlets of an iron-rich calcite with some finegrained quartz cut the quartz monzonite. The quartz 

monzonite at this locality must have been about at 

the upper boundary of the stock, for at the higher 

altitudes to the northeast and southwest are sedimentary rocks whose contacts with the igneous rock are 

nearly horizontal. 
120 GOLD HILL MINING DISTRICT, UTAH 

Two thin basic dikes were found in this vicinity and 

are shown in figure 14. Neither was traced for any 

distance because of the poor surface exposures, but 

they appear to have had no influence upon the ore. 

A light-colored quartz carbonate vein is also exposed 

nearby. It strikes a little west of north and may be 

traced for several hundred feet by means of its conspicuous light-colored float. 

The ore body was an irregular pipelike mass of 

pegmatite with a north-northeast trend and a nearly 

vertical dip. At the surface the mass had an elliptical 

shape with a long axis of nearly 60 feet and a short 

axis of about 30 feet. On the 50-foot level it was 

considerably smaller and had a circular outline about 

N 

j 

25 6 25 50 Feet ~~.~.~.~I----~I----~I 

FIGURE la.-Plan 01 main workings, Reaper claim. 

20 feet in diameter, from which two apophyses extended, one to the northwest and one to the northnortheast. On the bottom level the pipelike character 

is not apparent, and the pegmatite minerals are found 

in a lenticular zone striking northeast. Near the north 

end of the lens a blunt apophysis extends to the northwest. The deposit thus shows on a small scale a form 

characteristic of many larger bodies of ore-bearing 

material, a pipelike shape at the surface, which contracts in size downward and eventually changes into 

a tabular form. 

The walls of the pegmatite are not sharp and definite, as they simply mark the limit of replacement of 

quart~ monzonite by the pegmatite minerals. In general the boundary between wall rock and ore body is 

not notably irregular, but locally bunches of pegmatite 

minerals may be found beyond this boundary and 

entirely within the quartz monzonite. The apophyses 

noted in the preceding paragraph represent accelerated 

replacement of the wall rock along preexistent fractures. On the 50-foot and 100-foot levels small discontinuous stringers of pegmatite minerals in the 

quartz monzonite are the only indications of the 

approach to the blunt south end of the pegmatite. 

The two most abundant minerals in the pegmatite 

appear to have been green amphibole and pink orthoclase. The amphibole is found in sheafs as much as 

4 feet in length. It has been locally replaced along 

the cleavage planes by chlorite, biotite, muscovite, 

calcite, or quartz. Orthoclase is also found in large 

crystals, single cleavage faces as much as a foot across 

being noted .. It is later than the hornblende, which 

it has replaced. White albite is found with the orthoclase in some places. Apatite is surprisingly abundant. Much of it has a pink coloration due to films 

of iron oxide along fractures in the crystals, but a 

large proportion has a light cream color and closely 

resembles scheelite. Molybdenite and its oxidation 

product, powellite, are also found in many places. 

Black tourmaline, in many places accompanied by 

glassy quartz, occurs in considerable quantities around 

the edges of the pegmatite and is also present in 

bunches in the quartz monzonite wall rock. 

Small aggregates of sulphides, now largely oxidized, 

are locally conspicuous within the pegmatite. They 

are especially abundant at the north end of the bottom level, where with quartz they form much of this 

part of the pegmatite lens. Chalcopyrite appears to 

have been the most abundant sulphide but is now 

represented by copper pitch and malachite. In addition to these minerals, epidote, titanite, diopside, and 

zircon were identified microscopically. Subhedral 

magnetite was also found, a specimen from the dump 

showing the mineral embedded in a white calcite. 

Tungsten was present in the form of scheelite. Very 

little of this mineral can now be found either underground or on the dump. It is reported, to have occurred abundantly in the stope from the 50-foot level 

to the surface, in the central portion of the ,pipe. 

Butler examined this property during its development and writes as follows 48 concerning the occurrence 

of the scheelite: 

Adjacent to the shaft 49 a body composed largely of scheelite 

18 to 24 inches in thickness had been exposed for 4 or 5 feet 

along the strike and 3 or 4 feet below the outcrop. Deeper 

in the shaft other apparently smaller bodies of Bcheelite were 

exposed. The scheelite occurs in large crystals, some of which 

are 4 inches long. One block of nearly pure seheelite ore on the 

dump was estimated to weigh fully 200 pounds.. 

.. Butler, B. S., Ore deposits of Utah: U.S. Geol. Survey Prof. Paper 111. p. 476. 

1920. 

.. Tblssbaltwasin tbe part oftbe ore body removed during tbestoplng.-T. B. N~ 
MINES AND PROSPECTS 121 

The bodies of high-grade ore appear to occur as lenticular 

masses in the vein and suggest segregations of the scheelite 

through the pegmatite material of which the scheelite is an 

essential part. The scheelite was one of the earliest minerals 

to form. Much of it is in well-formed crystals and little of it 

includes the other minerals. 

According to the Wilson brothers, who developed 

the deposit, the ore also contained some gold. No 

bismuth minerals were found during mining, however. 

Pits 1 and 4 expose quartz veins that carry minor 

amounts of sulphides. Galena and tetrahedrite are 

the most abundant, but some chalcopyrite was observed. Malachite and other oxidized copper minerals 

are present, and some of the galena has been replaced 

by covellite. Xn specimens from pit 1 the quartz included irregular areas of barite and also a few euhedral crystals of this mineral. 

I I PI r NO.7 , 

"I 

I ~ Hornblende, quar tz, , specularite vein 'J 

Quartz 

monzonite 

PIT NO.1 

q ,~-Quartz-barite- 'S galena vein 

Rather similar pegmatites were present in pits 2, 5, 

7, and 8 (fig. 14), but little or no scheelite has been 

found in them. In all but pit 8, which is caved, the 

pegmatites had a distinctly veinlike habit and thus 

resembled the relatively barren lower portion of the 

main ore body. Pit 7 showed in addition to the usual 

pegmatite minerals a considerable amount of specularite, and much of the quartz in this body had a purple 

color, due to finely disseminated hematite. 

353l1-M--1l 

Feet 

Basic \ dike 

Quartz 

monzonite 

E.XPLANATION 

Vein 

)}SO 

St.rike and dip of vein 

strike vertical vein 

FIGURE 14.-Prospect pits and mineralization adjacent to Reaper open cut. 

About 1,000 feet northwest of the main shaft, on 

the adjoining Rex claim, also owned by the Seminole 

Copper Co., there is a smaller body of pegmatite 

that is of similar character to the main body of the 

Reaper. Some scheelite has been found at this place. 

In the altered wall rock of this body there are 

moderate amounts of disseminated sulphides, of which 

those recognized were pyrite, chalcopyrite, bornite, 

and molybdenite. 
122 GOLD HILL MI~ING DISTRICT, UTAH 

YELLOW HAMMER 

The Yellow Hammer property includes three claims 

about three-quarters of a mile northwest of Clifton. 

The Reaper group adjoins it on the east, and the Centennial on the west. The claims are owned by the 

Western Utah Copper Co. The property is developed 

by several shallow workings and by a shaft that was 

inaccessible at the time of the survey. The only 

recorded production was made in 1917, when 1,646 

pounds of scheelite that averaged 69.5 percent of WOa 

was shipped. 

The claims are all in the quartz monzonite, but sedimentary rocks are found nearby in every direction 

except to the southeast. As in the adjoining Reaper, 

the present surface at the Yellow Hammer is thought 

to be very near the original upper surface of the intrusive. The quartz monzonite where unaltered shows no 

pecularities, biotite or biotite and hornblende being 

the dark minerals. In many places, however, it shows 

a rather striking alteration to a pink fine-grained rock 

with numerous green splotches. Orthoclase appears 

to be the most abundant mineral in the pink portions 

of the rock, and the green mineral is an amphibole 

that is similar to those found in the ore bodies. A 

specimen of the wall rock of one of the tungsten-bearing 

ore bodies showed none of this alteration, however. 

In this specimen calcite, sericite, and chlorite were 

moderately abundant, and in addition it contained small 

quantities of a brown pleochroic epidote resembling 

allanite and numerous small crystals of titanite. 

The ore bodies that were seen on these claims are 

more tabular than pipelike and thus resemble the lower 

part of the Reaper deposit. The walls, like those of 

other deposits of this type, are not sharp. The vein-' 

like or tabular habit seems to be controlled by a major 

fracture, along which the ore-depositing solutions 

entered and from which they extended for varying 

distances into the walls. In many of the deposits 

mineralization has extended along other fractures at 

angles to the main one. All the deposits that were 

examined are of small size, having a length of less than 

25 feet and a width of less than 5 feet. 

The minerals forming the ore bodies are similar to 

those of the Reaper. Green hornblende, in many 

places altered to quartz and calcite, pink orthoclase, 

black tourmaline, albite, apatite, chlorite, muscovite, 

quartz, and sulphides, more or less oxidized, are readily 

recognized. Scheelite is rather irregularly distributed 

in the deposits. It was observed in several places in 

the prospect about 400 feet south of the main shaft. 

It can be readily recognized by its good cleavage, dullgray color, and greasy luster. In this deposit the long 

sheafs of hornblende show a strong tendency to occupy 

the central part of the ore body, and tourmaline is 

generally found near its borders. 

Copper, chiefly in the form of copper pitch, chalcopyrite, and malachite, is locally abundant in most of 

the ore bodies. Custer 50 writes that "samples from 

the ore exposed gave 0.40 to 0.62 ounce gold, 1.40 to 

3.80 ounces silver and 1.36 to 1.68 percent copper." 

DOCTOR 

The Doctor claim is just south of the junction of 

the branch road to the Yellow Hammer mine with the 

road from Clifton to Gold Hill, about three-quarters 

of a mile northwest of Clifton. It was owned in 1917 

by Duncan MacVichie, of Salt Lake City. ang, so far 

as known, still belongs to him. The developments 

consist of a shallow shaft, now inaccessible, and several 

surface cuts. A small amount of tungsten ore is 

reported to have been shipped from the claim. 

The claim includes the contact between the quartz 

monzonite and poorly exposed sandstones and limestones of the Oquirrh formation. The two principal 

openings, however, are in the quartz monzonite about 

50 feet east of the contact. In the more northerly one 

the ore seems to have occurred in a small pipelike 

body that has a diameter of about 5 feet and dips 

65°-70° W. The walls of the pipe are poorly defined, 

and bunches of silicate minerals occur in the surrounding igneous rock. In the southern prospect the ore 

zone is more veinlike. 

The ore was composed of scheelite, qU!1rtz, calcite, 

magnetite, and sulphide and silicate minerals. The 

silicates recognized include green crystalline epidote, 

pale-greenish scapolite, partly altered actinolite, abundant brownish-green garnet, black tourmaline, orthoclase, albite, chlorite, and sericite. The sulphide 

minerals occur chiefly with the quartz and include 

chalcopyrite, bornite, and pyrite. Copper pitch and 

malachite are plentiful as oxidation products. The 

sulphides are more abundant in the more southern of 

the two workings. No scheelite was observed bv the 

writer, but Hess,S! who examined the deposit in '1917, 

notes that "the scheelite is nearly white in pieces 

reaching more than 2 inches through. * * * A 

couple of hundred pounds of good ore is said to have 

been taken from the hole." He also notes the presence 

of bismuth in the deposit. 

CENTENNIAl, AND EN'fERPRISE 

The Centennial and Enterprise claims are about n 

mile northwest of Clifton, west of the Yellow Hammer 

mine and north of the road from Clifton to Gold Hill. 

The claims are reported to be owned by M. E. Jones; 

of Salt Lake City. The developments consist of 

several cuts and shallow shafts. Only one shipment 

from the property is recorded. This was made in 1917 

and consisted of 47 tons of ore that assayed 0.05 ounce 

of gold and 1.6 ounces of silver to the ton and 5.4 percent of copper. Scheelite is found in some of the 

'" Custer, A. E., Dool' Creek:, Clifton mining district, Utah: Eng. and Min. Jour.. 

vol. 103, p. 916, 1917. 

41 Hess, F. L., unpublished notes. 
MINES AND PROSPECTS 123 

prospect holes, but it is not known whether or not any 

tungsten ore was shipped. 

The claims cover the contact of the quartz monzonite with the Oquirrh formation. The trend of the 

contact here is irregular in detail, and both igneous 

and serumentary rocks have been considerably metamorphosed. Just west of the Enterprise claim the 

sedimentary rocks have been replaced by jasperoid, 

.and to the greater hardness of this rock is due hill 6455. 

The ore lies close to the contact in both the sedimentary and the igneous rocks. The pit near the south 

end of the Enterprise claim is on a pipelike mass in 

the quartz monzonite, whose position seems to have 

been controlled by the intersection of two fractures, 

one striking N. 7° E. and dipping 70° E. and the other 

striking N. 60° W.· and dipping south. Green amphibole, black tourmaline, apatite, calcite, quartz, and 

sulphide were recognized, in addition to much iron 

oxide and splotches of blue tourmaline, which together 

with sericite, quartz, and calcite is pseudomorphous 

after large crystals that were probably originally black 

tourmaline. In the prospect hole in quartz monzonite 

on the Enterprise claim the zone strikes N. 75° W. but 

apparently does not cross the contact into the sedimentary rocks. Black tourmaline is the most abundant 

mineral; green amphibole, jefferisite, quartz, muscovite, 

iron oxides, copper pitch, and malachite also occur. 

In the prospect in the Oquirrh formation on the 

Centennial claim the copper minerals are fOlmd in 

belts on a band of silicate rock that strikes northeast. 

The silicate minerals appear to be chiefly diopside and 

green amphibole. Magnetite is unusually abundant 

here, and with it are crystals of the green micaceous 

mineral jefferisite. Copper is found as copper pitch, 

malachite, and chalcopyrite. In one specimen 'Composed largely of porous green amphibole a poorly defined pinkish-gray patch proved to be chiefly scheelite. 

VEINS WITH SILICATE MINERALS IN THE GANGUE 

FRANKIE 

The Frankie mine is immediately west of the Lucy 

L mine and north of the Calaveras claim. It is owned 

by the Woodman estate. In addition to a number 

of surface cuts and pits, it is developed by a tunnel, 

whose portal is at the 5,972-foot point shown on the map 

and from which several stopes extend upward to the 

surface. The mine was actively worked in 1917~19, 

during which 3,056 tons of ore was shipped that had 

an average content of 0.08 ounce of gold and 1.5 ounces 

of silver to the ton, 4.8 percent of copper, and 0.7 percent of lead. The lead ore seems to have been obtained from a different deposit than the copper ore 

and to have contained relatively more silver and less 

gold. The writer was informed that some scheelite 

was found on the property and that a small quantity 

of it was shipped. 

The geologic relations at the Frankie are rather 

similar to those at the Calaveras, which adjoins it on 

the south. Metamorphosed limestones and sandstones of the Oquirrh formation cap the ridge above 

the mine workings and are limited on both the east 

and the west by dikelike masses of quartz monzonite. 

The dike on the east side is the narrower of the two, 

being from 200 to 500 feet across, and ends abruptly 

near the north end of the claim. On its east side it is 

intrusive into the Ochre Mountain limestone, and from 

the exposures to the north it is seen that this dike has 

followed the line of a normal fault separating the Ochre 

Mountain limestone from the Oquirrh formation. The 

outcrops of the Oquirrh formation in the region between the two masses of quartz monzonite are rather 

widely altered to garnet, diopside, clinozoisite, humite, 

and wollastonite. The quartz monzonite is also 

altered, a specimen taken from the southern pit at 

the contact with the sediments containing garnet, 

titanite, epidote, calcite, and chlorite as introduced 

minerals. 

The ore is found in a zone 20 feet or less in width at 

the contact of the eastern dike of quartz monzonite 

with the Oquirrh formation. The zone strikes west 

of north and dips about 65° E. at the north but steepens to nearly 90° at the south. Ore has been found 

for a distance of over 250 feet along the contact, chiefly 

in the metamorphosed sedimentary rocks and to a 

small extent in the quartz monzonite. 

The ore has a gangue of generally fine-grained silicate minerals. Black tourmaline and a green garnet 

are the most striking of these, possibly because in 

many places they occur, unlike the other silicates, in 

rather large, euhedral crystals. Diopside, amphibole, 

apatite, and humite also appear to be abundant, and 

calcite alone or with fine-grained quartz forms a matrix 

in much of the rock. The ore minerals are pyrite, 

bornite, and chalcopyrite with their oxidation products, chiefly copper pitch, chrysocolla, and malachite. 

The sulphides and to a less extent the silicate minerals 

show a pronounced tendency to occur in sheets parallel 

to the contact. This habit is probably the result of a 

preexistent sheeted zone parallel to the normal fault 

that apparently localized the dike of qnartz monzonite. 

A moderate amount of the sulphide, however, is found 

in blebs within the silicate rock. Thin sections of 

such ore show that the sulphides are almost invariably 

embedded in the calcite matrix rather than intergro\V'Il 

with the silicates. 

The copper content of the ore mined appears to 

have been rather constant throughout the stoped portion of the ore body. No scheelite was recognized 

in the field, and the average content of this mineral 

is not known but is presumably low. The deposit 

from which the lead ore was shipped was not examined 

during the survey. 
124 GOLD HILL MINING DISTRICT, UTAH 

CALAYERAS 

The Calaveras claims, owned by the Western Utah 

Copper Co., are about 2 miles south of Gold Hill, 

south of t.he Frankie claim and west of the Gold Bond. 

The developments consist of 4 shallow pits on the 

ridge line southeast of summit 6266 and 2 tunnels 

on the slope west of the ridge. Some shipments of 

ore are reported from the claims, but their grade and 

quantity are not known. 

The area covered by the claims includes part of a 

narrow band of the Oquirrh formation extending southward from the Frankie that is irregularly embayed by 

quartz monzonite. The igneous rock is a part of the 

dikelike mass that lies west of the main stock. Both 

sedimentary and igneous rocks have been extensively 

altered, and in many places it is extremely difficult 

to locate exactly the contact between them. 

Ore bodies are exposed both in the quartz monzonite 

and in the sediments. Those in the igneous rock are 

small pipelike shoots composed largely of quartz. In 

the northernmost pit in the quartz monzonite black 

tourmaline is abundant, but in the southernmost pit 

this mineral appears to have been replaced by a very 

fine-grained aggregate of blue tourmaline, sericite, and 

quartz. Blebs of copper pitch, in which are locally 

remnants of sulphides, are scattered through these 

gangue minerals, as are coatings of chrysocolla, azurite, 

and malachite. The specimens collected from these 

shoots contain a considerable amount of supergene 

chalcedony. 

The ore body in the sedimentary rocks strikes northeast and appears to be localized at the contact with 

the quartz monzonite. The gangue minerals are considerably more varied than in the quartz monzonite. 

Both a green and a reddish-brown garnet are abundant, together with a green amphibole, black tourmaline, orthoclase, and specularite. A flesh-colored 

fine-grained mineral that appears to have replaced all 

the gangue minerals just named was determined microscopically as humite. Quartz is not abundant. Pyrite 

and chalcopyrite are the most plentiful sulphides and 

in many places show comparatively little oxidation. 

Custer 52 reports that samples from the property 

assayed 0.11 to 0.20 ounce of gold and 0.20 ounce of 

silver to the ton and 1.99 to 9 percent of copper. 

POLE STAB CO.PPEB CO. 

The Pole Star Copper Co. formerly owned about 

15 claims in the vicinity of Lucky Day Knob, about 

halfway between Clifton and Gold Hill. All but two 

of these were unpatented and haye been abandoned. 

The two remaining claims are the Keno and the Pole 

Star, the former lying to the west of Lucky Day Knob 

and the latter to the east. The writer understands 

" Custer, A. E .• Deep Creek, Clifton miningdlstrlct, Utah: Eng. and Min. Jour., 

vol. 103, p. 916, 1917. 

that the Western Ut.ah Extension Copper Co. was 

under the same control. 

A considerable amount of development work has 

been done on the property. The chief openings are 

an inclined shaft on the Keno claim about 500 feet 

west of Lucky Day Knob, an inclined shaft on the 

Pole Star claim on the eastern slope of the knob at. an 

altitude of 6,075 feet, and two tunnels, one about 300 

feet south of the latter shaft and another about 800 

feet west-northwest of it. The recorded production 

from the company's claims amounts to shipments of 

313 tons in 1917. These averaged 0.096 ounee of gold 

and 3.65 ounces of silver to the ton and 2.96 percent 

of copper. 

Quartz monzonite underlies the greater part of the 

two claims. It has suffered a wide-spread but not 

especially intense alteration, during which sericite, 

chlorite, locally some orthoclase, and fine-grained 

quartz have been developed in the rock. Adjacent to 

the ore bodies sericite appears to be the most abundant 

of the introduced minerals. The summit of Lucky 

Day Knob is eomposed of Ochre Mountain limestone, 

and this formation is also found in several other places 

in the vicinity, suggesting strongly that the roof of the 

quartz monzonite stock was here close to the present 

surface. 

On the Keno elaim there are a few surface pits aud 

an inclined shaft. The shaft is now caved, but it 

appears to have been sunk on the intersection of two 

veins, one striking about N. 30° W. and dipping 70° W. 

and the other striking nearly west. The quartz monzonite wall rock is intensely sericitized at the shaft. 

The gangue minerals of the two veins observed were 

green hornblende, black tourmaline, quartz, and muscovite. The ore consists of oxidized iron and copper 

minerals, the latter being chiefly malachite, azurite, 

chalcedony, and copper pitch. Except for small 

amounts of pyrite, no sulphides were found in the ore 

on the dump. 

On the Pole Star claim the most thoroughly prospected vein strikes N. 40° W. and dips 35° SW. The 

wall rock is quartz monzonite that is thoroughly 

crushed and sericitized. At the inclined shaft the 

vein is from 3 to 5 feet wide, with local short spurs 

into the walls. 'V'here the tunnel south of the shaft 

intersects the vein the thickness is somewhat less and 

is notably variable, pinches and swells alternating 

within short distances. The ore is similar to that on 

the Keno clairi:l, tourmaline and quartz being the 

most abundant minerals. At the surface the oxidation 

of the ore minerals is complete, but on the tunnel level 

some sulphides still remain. F. L. Hess 53 during a 

visit to the property in 1917 recognized wolframite, 

scheelite, cuprotungstite, and ferberite (?) in this 

vein. 

R Unpublished notes. 
MINES AND PROSPECTS 125 

Published descriptions of the property 54 include 

assays that indicate the presence of local concentrations of copper-rich and silver-rich material; but t,he 

grade of the ore shipped seems to show that these 

concentrations must have had a rather slight extent. 

COPPEROPOLIS (IDA LULL) 

The Copperopolis or Ida Lull group of 6 patented 

and 20 unpatented claims lies on the southeast slope 

of Gold Hill, about three-quarters of a mile southeast 

of the portal of the Western Utah mine. The property 

in 1919 was owned by the Copperopolis Mining Co., 

161 South Main Street, Salt Lake City. It is also 

known locally as the Bamberger mine, after its principal owners. Nearly 550 tons of ore was shipped from 

1917 to 1919, the average metal content of which was 

0.11 ounce of gold and 5.5 ounces of silver to the ton, 

5.6 percent of copper, and 0.6 percent of lead. 

The south end of the mass of sedimentary rocks that 

occurs as a roof pendant in the quartz monzonite and 

underlies Gold Hill is included within the boundaries 

of the group of claims. The jasperoid mass that was 

formed along the fault passing through the crest of 

Gold Hill makes up most of this portion of the pendant. 

The Ochre Mountain limestone, which to the north 

is extensively exposed west of the jasperoid, is almost 

completely lacking at the surface in this region, quartz 

monzonite being in contact with the jasperoid over 

most of the distance. The only known outcrop of the 

Ochre Mountain limestone in this vicinity is at the 

southern tip of the pendant, where there is a small 

mass of lime-silicate rock, to which the limestone has 

been altered. Other small masses of altered Ochre 

Mountain limestone are !!xposed in the adit tunnel, 

whose portal is at an altitude of .5,517 feet. 

East of the jasperoid zone both the Manning Canyon formation and the Ochre Mountain limestone are 

exposed to the north. To the south, however, the 

Manning Canyon formation is cut out, owing to the 

more southeasterly strike of the jasperoid. The Ochre 

Mountain limestone outcrop is itself limited on the 

east by a westward-dipping fault that separates it 

from the quartz monzonite. The fault is well exhibited 

in a tunnel on the east side of the low knoll that marks 

the south end of the roof pendant. 

The ore bodies occur in lime silicate rock formed as 

a result of the metamorphism of the Ochre Mountain 

limestone. Three separate shoots have been developed. The largest and the one from which the bulk of 

the ore shipped was obtained is on the west side of 

the small knoll at the southern tip of the roof pendant. 

The ore shoot was localized along a nearly vertical 

shear zone in garnet-diopside rock that was 2 or 3 

feet wide and had a strike a few degrees east of north. 

The ore consisted of oxidized copper minerals and some 

.. Custer, A. E., Deep Creek, Clifton mining district, Utah: Eng. and Min. 

• Jour., vol. 103, p. 919,1917. Higgins, W. C., Flourishing conditiQIl of Clifton mining 

district: Salt Lake Min. Jour., vol. HI, pp. 21-26, July 15, 1917. 

blebs of the copper sulphides, chalcopyrite and bornite, 

in a matrix of silicate minerals. 

Two smaller ore shoots were found in the adit tunnel (fig. 15). One of these was very near the portal, 

in what was apparently a small mass of altered Ochre 

Mountain limestone on the footwall side of the jasperoid zone. The dimensions of this shoot were small, 

and the ore has been completely stoped out. Carl 

Bailey, of Gold Hill, reports that some scheelite was 

found in this ore shoot. The other ore shoot occurred 

near the face of the tunnel along a narrow fracture zone 

that here forms the contact between the quartz monzonite and the altered limestone. An interior shaft 

has been sunk to an unknown depth on this shoot, and 

two small stopes extend upward. Not much ore is 

exposed at this locality on the tunnel leveL A mass 

of nearly solid chalcocite more than 2 inches in diameter 

was found on the tunnel dump, but it is not known from 

which of the two ore shoots it was obtained. 

NAPOLEON MINING CO. 

The principal workings on the property of the N apoleon Mining Co. are about a mile north of the Western 

Utah mine, on the northwest slope of the small but 

prominent peak known locally as Calico Hill. The 

seven patented claims of the property have also been 

known as the Incas group and were at one time controlled by the Red Copper Queen Mining & Milling 

Co. Several small shipments of ore have been made 

from the property. Lots aggregating 135 tons that 

were shipped in 1917-18 averaged 0.11 ounce of gold 

and 2.6 ounces of silver to the ton and 6.4 percent of 

copper. 

The ore occurs in a small body of Ochre Mountain 

limestone that on the west and south is irregularly 

embayed by the quartz monzonite and on the east is 

separated by a fault from beds belonging to the central 

facies of the Oquirrh formation. The limestone is for 

the most part bleached and recrystallized, but locally, 

particularly near the contact with the intrusive, it 

is altered to silicate minerals. In other places it has 

a pronounced pinkish-brown color due to the widespread presence of small quantities of iron oxides. 

Locally the iron oxides are concentrated into "iron 

blowouts." Such masses, however, are shown by several prospect pits to have relatively small dimensions. 

The ore bodies have been developed by several shallow pits or short tunnels and also by two shafts, both 

of which are now inaccessible. 

The ore shoots consist of small lenses of copperbearing lime-silicate rock within a few feet of the quartz 

monzonite contact. The ore minerals are all oxidized 

copper compounds, chiefly copper pitch, malachite, and 

chrysocolla. No sulphide minerals were observed. 

GOLD BOND 

The Gold Bond claim is in Lucy L Gulch, about 

1,500 feet south of the main Lucy L tunneL It is 

-
 •
126 GOLD HILL MINING 

now reported to be owned by the Galinske brothers, 

of Sioux City,Iowa, but in 1917 it appears to have 

been the property of the Babcock Mining Co. One 

shipment, presumably of copper ore, is said to have 

been made from the property some time ago, but the 

amount and grade are not known. The developments 

on the claim consist of a tunnel, whose portal is 800 

feet west of the cabin at an altitude of 6,053 feet, and 

several shallow pits. The claim appears to have been 

actively worked in 1917-18. 

The country rock consists of altered quartz monzonite, in which the dark minerals have been replaced 

by calcite and chorite and much of the remainder of 

Ochre Mountain limestone 

largely altered to 

lime-silicate rock 

'" 

EXPLANATION 

Fracture 

60° 

~ Stri ke and dip' of' -fault 

-+-­

Strike of vertical contact 

DISTRICT, UTAH 

ularite are the most abundant minerals. The specularite has been locally altered to a reddish powdery 

oxide and in such places is generally associated with 

quartz or chalcedony. Coarsely crystalline glassy 

quartz is also found in parts of the vein, and much 

of the copper ore is associated with it. Diopside, 

amphibole, biotite, a white scapolite in part sericitized, orthoclase also locallysericitized, and purple 

and white fluorite are found less abundantly. Danburite, the calcium borosilicate, is surprisingly abundant in the vein but in many places has been partly 

replaced by calcite. In the pit on the vein southeast 

of the tunnel portal danburite makes up a large part 

5.... P-'-.1-,-,--,-I....9___'--__-'-__-'110 Feet 

Stope a.nd raise to surface 

in lime -silica.te rock? 

FIGURE l5.-Plan ot Bdit tunnel, Copperopolis group. 

the rock by a fine-grained mixture of quartz, orthoclase, 

and albite. The quartz monzonite is near the eastern 

edge of an irregular mass that lies west of the main 

stock. Ochre Mountain limestone underlies the eastern part of the claim. 

The largest vein on the claim is exposed in the tunnel. It strikes N. 50° W. and dips 45° SW. The vein 

zone is about 5 feet wide, but this figure includes nearly 

1 foot on each wall that is composed of quartz monzonite largely replaced by massive dark epidote and 

smaller amounts of other silicate minerals that are 

also found within the ore-bearing portion. In the 

cen tral portion of the vein black tourmaline and specof the vein and has clearly replaced the other silicates 

and specularite. The ore minerals are copper pitch, 

in which are remnants of chalcopyrite, and other oxidized copper minerals, chiefly chrysocolla and malachite. Much of the copper pitch is found within 

quartz, but some of it is embedded in the silicates. 

It!was ~reported [that during t,he~ period,:of activity at 

this mine the ore taken out carried 2 to 4 percent 

of copper.55 The writer's observations indicate that 

the distribution of the copper minerals in' the'. vein is 

irregular. 

"Schwalenberg, L. G., Mining In the Deep Creek region: Salt La.ke Min. Rev., 

vol. 19, p. 43, January 15, 1918. 

-
MINES AND PROSPECTS 127 

There are three other veins on the claim that have 

a similar strike. All three, however, appear to have 

a small horizontal extent and might better be described 

as pipelike. They carry ore of a similar type but 

show rather less diversity in the number of minerals 

present. 

COPPER BLOOM 

The Copper Bloom group of claims is about halfway 

between the towns of Clifton and Gold Hill, adjoining 

the Keno claim on the west and south. It is owned 

by the Copper Bloom Mining Co., in which the Wilson 

brothers, of Salt Lake City, are the guiding spirits. 

Shallow shafts and cuts constitute the developments, 

but, so far as known, there has been no production. 

The quartz monzonite that forms the walls of the 

ore bodies is a part of the main Gold Hill stock. The 

area covered by the claims is near the western border 

of the stock, which is, in plan, highly irregular. Several roof pendants composed chiefly of Ochre Mountain limestone are found east and northeast of the 

claims within the quartz monzo,nite. 

Four ore bodies have been exposed on the claims. 

In all of them black tourmaline with a sheaf-like habit 

and smaller amounts of coarsely crystalline quartz 

are the most abundant minerals. The two more westerly deposits are about 1,500 feet south of west of the 

old Keno shaft. One of these is a vein striking N. 

45° E. and dipping about 65° SE. The vein filling 

consists of black tourmaline with some quartz. Abundant pulverulent iron oxide fills areas formerly occupied 

by sulphides. Some chalcedony veinlets and coatings 

of yellow-brown jarosite were also recognized. The 

iron oxide is said to be rather rich in gold, with the 

result that locally assays of $50 a ton have been obtained. Some bismuth is also reported from this vein, 

but none was recognized in the specimens collected. 

Nearby a shaft has been driven on a vein that strikes 

north and dips east. Black tourmaline and quartz 

• 	 are the most abundant minerals, as in the other deposit, 

but instead of the iron oxides there are splotches of 

copper pitch, which contain remnants of chalcopyrite 

and pyrite. In one specimen a pseudomorph of bismutite after bismuthinite has the same relations to 

the gangue as the copper pitch. Azurite, malachite, 

and a clay mineral that is probably beidellite occur 

in small quantities. Tungsten minerals and gold are 

reported also to be present. This vein is not persistent downward. 

A few hundred feet east of these two veins a similar 

vein is exposed. This strikes N. 10° W. and dips 

45° E. and is about 3 feet in width. Near the bottom 

of the shaft the vein is displaced about 2 feet by a 

westward-dipping normal fault. The vein filling consists chiefly of tourmaline and quartz, in which are 

local concentrations of muscovite. Unreplaced remnants of the bleached and altered quartz monzonite 

that forms the walls also occur within the vein. In 

this gangue are found patches of the ore minerals. 

Those observed include pyrite, chalcopyrite, tetrahedrite, and gold. Oxidation products are chalcocite, 

covellite, copper pitch, malachite, azurite, bismutite, 

and a dark-gray copper-bismuth mineral that is 

probably a very intimate mixture of bismutite and 

chrysocolla. Specimens rich in these ore minerals are 

reported to assay as high as 60 ounces to the ton in 

silver and $20 to the ton in gold. 

Still farther east, about 500 feet south of the old 

Keno shaft, a fourth ore body has been prospected. This 

has a pipelike form, in contrast to the other deposits, 

and pitches steeply to the southeast. It is mineralogically similar to the vein deposits except that sulphide 

minerals are somewhat less abundant and that apatite 

and scheelite are both present, locally in considerable 

quantity. Apatite was found both as small creamcolored crystals and as large greenish masses that had 

replaced the tourmaline. Scheelite occurs as large 

greasy-appearing grayish crystals partly replaced by 

tourmaline. Bismuth minerals are reported to occur 

in this deposit, but none were recognized in the speci-­

mens collected. 

VICTORY NO. 1 

The Victory No.1 claim, owned by the Hudsons, 

of Gold Hill, is about 1,500 feet southeast of the road 

fork at an altitude of 5,783 feet on the Lincoln Highway south of the town of Gold HilL Several surface 

workings have been opened on the claim, but so far as 

known no ore has been shipped. 

The claim is near the contact of a broad tongue of 

quartz monzonite from the main stock, with limestone 

and dolomite of the Oquirrh formation. The sedimentary rocks have been locally replaced by jasperoid. 

The ore body is a vein that strikes about N. 50° W. 

and dips vertically within the quartz monzonite, but 

at its intersection with the sedimentary rocks it changes 

its course to follow the contact. Quartz and black 

tourmaline with some cream-colored apatite are the 

most plentiful gangue minerals. Pyrite, chalcopyrite, 

and tetrahedrite occur in blebs and patches throughout the rock; the pyrite and chalcopyrite are more 

abundant in the tourmaline, and the tetrahedrite is 

localized in the quartz. "Limonite," azurite, malachite, chalcocite, and chrysocolla are o:lI,:idation products. No assays of the ore are available, but it is 

certain that the average grade is low. 

MINNEHAHA 

The Minnehaha group of 13 claims lies along 

Goshute Wash about a mile east of Montezuma Peak. 

The claims, of which three are patented, are owned 

by P. H. Robinson, of Gold Hill. Mr. Robinson 

reports that small shipments of ore were made from 

one of the patented claims, the Albert, in 1912 and 

1925. These contained $1.60 in gold and 6 or 7 ounces 

of silver to the ton and from 5 to 16 percent of copper. 
128 GOLD BILL MINING DISTRICT, UTAH 

The claims cover a considerable distance along the 

contact between the quartz monzonite and the Oquirrh 

formation. The contact in this region dips to the 

east-southeast at a moderately low angle. The 

Oquirrh formation has been conv~rted to jasperoid 

for as much as 50 feet above the contact. The ore is 

found in the jasperoid in shMtlike layers 5 to 10 feet 

above the contact. Over much of the distance the ore 

zone is essentially barren and consists of jasperoid 

very rich in iron oxides, much of it carrying 20 percent or more in iron. Locally, however, the material 

is cupriferous, and the most abundant copper mineral 

is a siliceous copper pitch, in which are not uncommonly remnants of chalcopyrite. Chrysocolla and the 

basic copper carbonates are locally conspicuous but 

are probably unimportant as ore minerals. One specimen from the Albert claim contained considerable 

arsenopyrite, but this mineral was not noted elsewhere. 

There has been considerable post-ore shearing in the 

vicinity, both along the ore horizon and at the underlying contact of the jasperoid with the quartz monzo­

. nite. 

Another small copper prospect on the group is a 

short distance southwest of Mr. Robinson's house, 

within a small block of limestone surrounded by quartz 

monzonite. The limestone has been largely converted 

to lime-silicate rock, in which there has been a slight 

copper mineralization similar to that at the Frankie 

mine. 

OZARK 

The Ozark group of claims, about a mile southeast 

of Montezuma Peak, is reported to be owned by F. 

M. Johnson, of Wendover. A shipment of 12 tons of 

ore from this group in 1917 contained 0.11 ounce of 

gold and 5.1 ounces of silver to the ton and 3.2 percent 

of copper. 

In the vicinity of the claims a small triangular plug 

of quartz monzonite, satellitic to the main stock, is 

intrusive into the Oquirrh formation. The sedimentary rocks here are composed of interbedded thin 

limestones and sandstones. The limestone beds in 

particular have been thoroughly altered in the vicinity 

of the workings, in part to silicate minerals and in part 

to jasperoid. 

Two ore shoots are present on the property, both 

in the sedimentary rocks near the quartz monzonite 

contact. The larger one is a vein striking N. 20° W. 

and dipping 60° E. The hanging wall of the vein is a 

dark porphyry dike and the footwall a mass of jasperoid 25 feet in width. The ore mined contained 

abundant iron oxides and various copper minerals, of 

which copper pitch appears to have been the most 

plentiful. In the more westerly workings on the claim 

scorodite and arsenopyrite appear to be the only ore 

minerals present. 

COPPER HILL 

The Copper Hill group of unpatented claims is on 

the west and southwest side of hill 5852, a little less 

than 2 miles north of west from the town of Gold Hill. 

In 1926 it was owned by J. C. and H. V. Hicks, of 

Salt Lake City. 

The ore shoots are in lime-silicate rock produced by 

the alteration of limestone beds in the Oquirrh formation. They occur near dikelike masses of quartz 

monzonite that were intruded in part along a northwestward-striking fault that brings the Manning 

Canyon formation into contact with the Oquirrh 

formation. The mineralization was rather scanty, 

copper pitch and other oxidized copper minerals being 

found locally in ore shoots of small dimensions. 

ALVARADO 

The Alvarado mine is about 1 mile east of the town 

of Gold Hill and half a mile northwest of the Western 

Utah Copper Co.'s Gold Hill mine. It is now owned 

by the Woodman Estate. The writer was informed 

that difficulty in securing united action by the large 

number of heirs to the estate has prevented recent 

attempts to work the mine. The mine workings consist of an inclined shaft about 250 feet deep and about 

1,500 feet of tunnels, in addition to short raises and 

winzes (fig. 16). A shaft house and a bunk house, both 

in need of repair, are on the property, which adjoins 

the spur of the railroad to the Western Utah property. 

The bulk of the production from the mine was made 

in the period from 1892 to 1895, during which it is 

supposed to have produced about $120,000 in gold. 

Since that time the mine has been idle for the most 

part, although several small shipments of ore have 

been made. One lot of 25 tons is reported by William 

Darnell to have been shipped in 1909 and another of 

35 tons in 1916. 

Since the field work for this report was completed 

some ore has been extracted froin the mine by lessees. 

Toward the end of 1931 the Aurum Mining Corporation 

was reported to have obtained control of the property. 

Two formations are recognized near the Alvarado 

mine-Ochre Mountain limestone and quartz monzon· 

iteo '}'he thick beds of limestone are generally bleached 

to a dazzling white color and are coarsely crystalline. 

Locally silicate minerals have replaced the limestone; 

the most wide-spread is wollastonite in bladed crystals as much as an inch in length. One notable exposure of this mineral was found a short distance southeast of the shaft house. The beds strike rather uniformly a little west of north and dip steeply to the 

east. 

The quartz monzonite is not notably different from 

the average for this formatioh. Biotite appears to 

be the most abundant of the primary dark minerals, 

-
MINES AND PROSPECTS 129 

but diopside, partly altered to hornblende, has been 

introduced into the rock in many places. In a specimen from the east end of the 200-foot level magnetite 

2" 0 I! II I I 

FIGURE I6.-Plan of Alvarado mine workings. Blank areas are limestone. 

and smoky apatite are unusually abundant sw. 

accessory minerals and quartz is relatively rare. 

Calcite and pyrite are secondary minerals in 

this place; as in several others. 

The quartz monzonite is a part of the main 

stock, and its contact with the limestone beds, 

about 150 feet southwest of the shaft, is 

approximately parallel with their strike. This 

contact is also exposed on the 100-foot level, 

where the dip is steep to the northeast. A 

dike from the main body about 20 feet wide 

is also exposed at the surface. At the shaft 

the dike has a course that is approximately 

the same as that of the bedding and dips 

steeply to the northeast. It does not extend 

to the northwest much beyond the mine workings but may be traced with the same strike 

about 200 feet to the southeast. There the 

strike swings sharply to the south, and the 

width increases rapidly until a junction with 

the main body of the stock is effected. 

Underground the dike is found to have some 

minor irregularities. On the 40- and 60-foot 

levels, for example, it cuts across the bedding 

of the limestone at a low angle, thereby terminating 

the main are body. On the 100-foot level irregularities 

also appear. The hanging-wall crosscut just south of 

the shaft shows a mlillmum thickness of 60 feet for 

the dike, although only 20 feet was found at the 

surface. Further, near the shaft the contact of limestone and quartz monzonite on the 100-foot 

level is almost vertically beneath the contact 

on the 60-foot level, indicating that here the 

dike transgresses the dip of the beds. Finally, 

at the south end of the 100-foot level, a hanging-wall crosscut discloses 25 feet of limestone 

between walls of quartz monzonite. These 

features indicate that the dike branches at this 

altitude near the shaft, and that the southwesterly branch is a spur that extends upward 

so short a distance that it is not exposed on the 

60-foot level (fig. 17). The block of limestone 

between the two branches apparently reaches 

a greater depth to the south than it does near 

the shaft. 

The 200-foot level adds little to the knowledge of the dike except that its dip must flatten 

notably below the 150-foot level. The extension 

of the shaft below the 200-foot level, however, 

again cuts quartz monzonite and strongly suggests a reversal of dip, as shown in the section. 

The bottom level also shows three other 

exposures of quartz monzonite in the workings northwest of the shaft. All of these 

are rather irregular lenticular masses with 

relatively small cross sections. The limeHE. 

? 

Feet 

FIGURE I7.-Geologic cross section through Alvarado shaft. 

stones surrounding these masses have undergone a 

rather extensive replacement by silica. Much of this 

is in the form of fine-grained quartz that has veined 
130 GOLD HILL MINING DISTRICT, UTAH 

or irregularly replaced the calcite, but locally thin 

lenses of chalcedony, which are bordered by quartz, 

are present. In many places the altered rock is colored a deep brown by specks of a finely disseminated 

mineral of that color. The several exposures of quartz 

monzonite on this level and the abundant silicification, 

together with the apparent reversal of dip of the dike 

indicated by the presence of the igneous rock in the 

bottom of the shaft, lead the writer to the belief that 

the limestone will be bottomed at no great distance 

below the level. 

The ore bodies of the mine consist of irregular shoots, 

carrying a minable amount of gold in limestone that 

has been almost completely replaced by silicate minerals. Two chief ore bodies have been exploited. 

One, which may be called the main ore body, is 

much larger than the other, here designated the footSE. 

200'LEVEL 

25 0 100 Feet ~!lUI~I~I~I__ __ __ __~1 

FIGURE IS.-Stope projection on plane through shaft, Alvarado mine. 

wall ore body. (See fig. 18.) It has been followed 

from the surface down to the 200-foot level and has 

been stoped over a width as great as 40 feet, with an 

average between 5 and 10 feet. The stope length 

reaches a maximum of about 120 feet on the 60-foot 

level and decreases considerably on the lower levels. 

The dike of quartz monzonite forms the hanging wall 

of this deposit almost throughout its extent, except 

for the portion below the 150-foot level, where limestone forms both walls. In this region the tabular 

form of the ore body is replaced by a roughly pipelike or cylindrical shape. On the upper levels the 

stopes indicate a pitch to the northwest. This may 

be the result, at least on the 60-foot level, of the transgression of the limestone bedding by the dike. Westtures were found in the pipelike bodies on the 200-foot 

level. The "'Titer feels that they have played a much 

more important part in localizing the ore shoots than 

the presence of the dike of quartz monzonite, for, as 

noted in a previous paragraph, most of the pipelike 

ore bodies and some parts of the tabular bodies may 

be found within walls of limestone. 

Where quartz monzonite forms the hanging wall of 

the ore body the line between ore and waste is sharp 

and is found at the igneous contact. The limestone 

walls, however, are not sharp and appear to have been 

determined by assay, rather than by any obvious 

mineralogic change, for silicate replacement of limestone extended far beyond the limits that have been 

reached by the stoping. 

ward-dipping cross fractures, however, may also have 

influenced the pitch. The division of the ore body 

into two parts below the 60-foot level also appears to 

be the result of the position of the dike, as the unstoped 

region corresponds in position with the junction of the 

two branches of the dike that has interrupted the orebearing bed. 

The footwall ore body is comparatively small and 

was stoped only from the 60-foot level to a point a 

few feet above the 40-foot level. Its maximum stope 

length was about 30 feet. The northwestern part of 

this shoot had the dike of quartz monzonite for a hlmging wall, but the remainder had limestone on both 

walls. A minor amount of stoping was done on the 

60-foot level along the limestone and quartz monzonite 

contact in a way to connect the two ore bodies. It 

could not be ascertained, however, whether the mateNW. 

rial removed contained gold or whether 

the work was done in the expectation 

that the ore should be found along the 

contact. 

In addition to these two main ore 

bodies there appear to have been several 

pipes of ore on the 200-foot level, for 

moderate amounts of stoping have been 

done from the several winzes and raises . 

shown on the map. One of these pipes 

is entirely within a lenticular mass of 

quartz monzonite. The remainder are 

in the limestone. 

A notable feature of most of the stoped 

areas is the general presence of cross 

fractures, striking somewhat east of 

north and dipping steeply, for the most 

part to the west. These are locally filled 

with wollastonite and other silicates, 

quartz, which is in part chalcedony, and 

oxidized iron and copper minerals. In 

most places the stope width appeared to 

reach a maximum where these cross fractures were intercepted. Similar frac­
MINES AND PROSPECTS 131 

The greater part of the ore mined consisted of sili- I 

cate minerals that had replaced limestone, with which 

were associated considerable amounts of quartz, small 

amounts of sulphide minerals with their oxidation 

products, and native gold. The most widespread 

silicate mineral appears to be wollastonite, which in 

many places has been largely replaced by fine-grained 

fibrous spadaite. This alteration resulted in a massive, 

almost porcelaneous rock of a cream or pale-pink color. 

Smaller amounts of green diopside and brown garnet 

are also abundant, and Kemp 56 in addition mentions 

zoisite, vesuvianite, tremolite, and serpentine. The 

relations between the tremolite and serpentine as 

described by Kemp are similar to those noted between 

wollastonite and spadaite. 

The silicate minerals have been replaced or cut by 

irregular areas or veinlets of quartz. .Both megascopically crystalline and very fine-grained quartz have 

been recognized, and the latter is the younger. In 

addition, chalcedony is 'of frequent occurrence, but 

it seems in most places to be the result of weathering. 

Calcite veinlets of several ages with respect to the 

quartz are also abundant. 

The sulphides recognized are pyrite, galena, chalcopyrite, bornite, and chalcocite. They are relatively 

rare in this mine but have been found both in the silicate rock and quartz veins. The occurrences in association with quartz are the more abundant. The 

most striking occurrence of sulphides is on the 200-foot 

level just south of the shaft. This exposure is not on 

either of the two chief ore bodies, and as it has not 

been stoped, presumably it is not rich in gold. This 

body has been thoroughly oxidized and now consists 

of brown resinous copper pitch with a few remnants 

of sulphides, which shows local alteration to iron oxides, 

a lighter-brown jarosite, blue crystalline chalcanthite, 

and a pale-greenish mineral that has the optic properties of siderotil, a hydrous iron sulphate. 

Native gold is said to have been locally very abundant and to have bee~ found in pieces" as large as a 

bean." William Darnell, who has worked in the mine, 

says that it was especially abundant in the spadaite 

areas, particularly where that mineral contained copper minerals or quartz veinlets. No gold was collected in the mine by the writer, but in specimens 

which he has seen the native gold is crystalline and is 

associated with oxidized copper and iron minerals and 

with chalcedony. The enclosing rock in these specimens was quartz and spadaite. Kemp 57 described 

native gold from this mine associated with zoisite, 

limonite, and malachite. 

In the pipelike ore bodies on the 200-foot level the 

silicate minerals appear to be much less abundant. 

Small quantities of diopside and a very fine-grained 

mineral that is probably spadaite were recognized in 

'~Kemp, r. F., Notes on Gold Hill and vicinity, TooeJe County, Utah: Econ. 

Geology, vol. 13, pp. 258-259, 1918. 

" Kemp, J. F., op. cit., pp. 258-259. 

the thin section studied, but the bulk of the rock is 

composed of calcite replaced by fine-grained quartz. 

No sulphides were noted in these pipes. Oxidation 

products are much more abundant near the ore bodies 

on this level than elsewhere, perhaps because of the 

greater abundance of easily replaced calcite. 

The grade of the ore is reported to have been rather 

variable. No figures are available for the Alvarado 

mine alone. An examination of the assay records of 

the mill that treated ore from the Alvarado, Cane 

Springs, and Gold Hill mines, showed that the heads 

assayed from $4 to $35 a ton, of which about 80 percent was recovered. The average content during a 

period of slightly less than two years was $10.28 a ton. 

Bullion assays indicated a fineness of 0.750 to 0.850. 

Some of the gold, however, is reported to have been 

0.950 fine. CANE SPRINGS 

The Cane Springs mine is about 2,000 feet southwest of the town of Gold Hill and 250 feet west of 

U.S. Mineral Monument No.7. Like the Alvarado, it 

is owned by the Woodman Estate, and similar difficulties are reported to have been met in attempts to 

reopen the mine. The development consists of an 

inclined shaft 150 feet deep, two short winzes, and 

about 1,000 feet of drifts and crosscuts (fig. 19). A 

vertical shaft connects the most easterly workings with 

the surface but appears to have been little used. 

In 1931 work was resumed at the Cane Springs 

mine by G. H. Short, of Salt Lake City, under a 

3-year lease with an option to purchase the property. 

Toward the end of the year the Aurum Mining Corporation was organized to operate this lease together 

with one on the Alvarado. Development was actively 

prosecuted, and at the end of 1932 it was reported that 

25 tons of ore a day was being mined, of an average 

grade of about $12 a ton. 

The production of the Cane Springs mine is not 

accurately known. Its period of greatest activity 

appears to have been from 1892 to 1895, when the 

gold production was probably between $50,000 and 

$70,000. A shipment of 46 tons reported from the 

Cane Springs claim in 1914 contained 1.07 ounces of 

gold and 3 ounces of silver to the ton and 5.5 percent of copper. 

The mine is in a rather narrow northwestwardstriking belt of Ochre Mountain limestone. This is 

separated from the Oquirrh formation on the southwest by a normal fault of rather large throw, whose 

strike cuts that of the limestone at a small angle, with 

the result that individual beds are progressively cut 

out to the northwest, the uppermost one disappearing 

just southeast of the wash in which Cane Spring is 

located. The limestone is overlain by the Manning 

Canyon formation. Two small plugs of quartz monzonite cut the limestone belt, one about 1,000 feet northwest of the main shaft and the other, larger one a 

similar distance to the southeast. The main body of 
132 GOLD HILL MINING DISTRICT, UTAH 

the quartz monzonite stock crops out only a slightly 

greater distance to the east. 

The limestone is similar to that exposed at the 

Alvarado-massively bedded, bleached and recrystallized, and locally altered to silicate minerals. It 

has a rather constant northwest strike and dips 

550 -650 NE. The Manning Canyon formation above 

is not well exposed but appears to have been rather 

generally metamorphosed to a dark andalusite hornfels. 

The only igneous rocks found in the mine are two 

dikes, each a foot or so thick. These occur along two 

fault planes, one exposed on the third level and the 

N 

t 

l 

passes into either a sheeted zone in metamorphosed 

limestone, as near the portal of the tunnel level, or a 

tight barren fissure within silicate minerals. The 

greatest stope length is on the first or tunnel level 

and amounts to about 125 feet. 

Cross fractures are prominent within the ore shoots. 

These strike nearly east and dip steeply to the south. 

Mineralization similar to that of the ore body has 

occurred along these fractures and extended outward 

into the walls. One such fracture is excellently displayed in the winze connecting the third and fourth 

levels. 

EXPLANATION 

~A<0,£» 

Stope 

Fault or fissure 

so'y 

Strike and cl.p 

-estrike of vertical fissure 


F;;:stlevel 

Third and lower levels 

s' 

c· 

vERTICAL SHAFT 

TO SURFACE 

Approximate contact?' 

:\. Ochre Mountain lime­

/i'VERTICAL stone.and Manring Canyon formabon 

FIGURE 19,,-Plan of Cane Springs mine workings. For sections on lines A-A', B-B'. and C-C' see figure 20. 

other on the fourth level. The dike rock is a dull 

brownish-gray fine-grained rock in which flecks of iron 

oxide are the only constituents readily recognizable. 

The microscope shows that it has been thoroughly 

altered and is now composed chiefly of fibrous pleochroic hornblende and sericite, together with smaller 

amounts of apatite, chlorite, calcite, and iron oxides. 

There is also a greenish isotropic mineral of high relief 

that is probably spinel. RectangUlar areas of sericite 

apparently represent former feldspar phenocrysts. 

The ore body is found in a thick bed of limestone 

that has been almost completely replaced by silicates, 

quartz, and sulphides. The walls appear in large part 

to have been assay walls, and the width stoped ranges 

from about a foot to 20 feet. Laterally the ore shoot 

The continuity of the ore shoot is broken by six or 

seven low-angle faults (figs. 20 and 21). These have 

rather widely different strikes that range from northnortheast through east-west to north-northwest, considerable variations in strike being observed in a single 

fault. They are all alike, however, in having a low 

dip-25° to 35°-which always has a northerly element 

in its direction. The sections in figures 20 and 21 show 

an apparent gap in the ore above the third level, 

but it seems probable that this was actually stoped, 

for the ore shoot is shown by Billingsley 58 to be essentially continuous through this section. These workings 

if they are present, are probably now concealed by the 

.. Billingsley. Paul. Notes on Gold Hill and vicinity. Tooele County, Utah: Econ. 

Geology, voL 13, p. 272, 1918. 
MINES AND PROSPECTS 133 

filling at the bottom of the raise connecting the second 

and third levels. . 

The offsets of the ore shoot by the faults are not 

consistent among themselves. Some, particularly 

?

-,\ 
 Thjrdlev~ \ \ 

on section A A ~ '7, , 

\ , 

\ \ 

\ Third lavel on section 88' 

rn 

Vein 

[§] 

Fault 

FIGURE 20.-Composlte section along lines A-A', B-B', and 0-0', figure 19, through 

Cane Springs mine. Sections B-B' and 0-0' have been shifted both vertically 

and horizontally relative to A-A' so that individual faults appear continuous. 

those on the higher levels, require reverse movement 

,,\li.th a large horizontal component, but others show 

equally large offsets that require the normal type of 

movement, though also with horizontal components. 

These relations of the faults 

suggest that they were formed SE. 

before ore deposition and that 

the apparent displacement of 

the ore by the faults is rather 

the result of a control of ore deposition by the faults. The reasons for this 'view are as follows: 

The two dikes described in a 

preceding paragraph are intruded along the faults and thus 

are clearly younger. The dikes 

are themselves metamorphosed, 

and if it is held that faulting 

followed the deposition of the 

gold ore it becomes necessary to 

assume two periods of silicate 

metamorphism separated by an 

epoch of both reverse and normal faulting. This is difficult to accept in view of the 

fact that in other parts of the district mineralization 

has clearly followed dike formation. 

The shapes of the portions of the ore shoot between 

faults offer some evidence. Although it is realized 

that the stoped areas had very different gold contents, 

a rough approximation to similarity in dimensions on 

both sides of a fault might be expected, but figure 21 

shows that such a similarity is not present. Furthermore the extension of the stopes upward along the 

fault plane, as shown especially well by the stope above 

the end of the second level, suggests very strongly a 

greater age for the fault, which thus dammed and 

directed upward the incoming ore-forming material. 

The apparent displacement of the ore shoots by the 

faults is difficult to accept on the theory that both 

reverse and normal faults, which are roughly parallel 

in attitude, could have formed in the interval between 

ore deposition and dike formation and be unrecognized 

elsewhere in the quadrangle. It is much more probable that the ore solutions entered along the closely 

related cross fractures and that .deposition was controlled by preexisting faults, whose present attitudes 

may be quite different from their original ones. 

The ore is similar to that of the Alvarado and Midas 

mines. Wollastonite, which is locally fibrous, is the 

most abundant silicate mineral and in many places 

has been altered to spadaite. Pinkish-brown garnet, 

green diopside, and greenish-brown vesuvianite and 

zoisite are also found. Fine-grained quartz and calcite 

cut the silicates in veinlets and more irregular masses. 

Sulphides and their oxidation products are relatively 

more abundant in the mine and consist of pyrite, 

chalcopyrite, bornite, chalcocite, CQvellite, and molybdenite. The molybdenite is reported to have been 

found very plentifully near the surface. These minerals occur in veinlets cutting the silicate minerals. 

NW. 

50 0 50 Feet ~I~.~~~~I______~I 

FIGURE 21.-Stope projection, Cane Springs mine. 

• No gold was observed in the specimens collected by 

II the writer. William Darnell, who worked in the mine, 

informed the writer that the best ore was found near 
134 GOLD HILL MINING DISTRICT, UTAH 

concentrations of copper minerals. Kemp,59 however, 

has described the occurrence of native gold embedded 

in silicate minerals. 

No data are now availa'ble as to the grade of the ores 

other than those quoted in the description of the 

Alvarado mine-namely, that the mill heads, on ore 

from the several mines, ranged from $4 to $35 in gold 

to the ton and the recovery averaged $10.28 a ton 

over a period of 2 years. It is said that the Cane 

Springs ore was somewhat more refractory than that 

from the other mines because of the higher content of 

sulphide minerals. Either for this reason or perhaps 

because of a generally lower grade, the stoping in this 

mine shows that only the most accessible material 

was mined. MIDAS 

The Midas mine is on the south side of Montezuma 

Peak, just east of Hopkins Gulch and a little more 

than a mile east-southeast of Mineral Monument 

No.9. Four patented claims are owned by the Midas 

Gold Mining & Milling Co., of Salt Lake City, Utah. 

The mine developments consist of an adit tunnel in 

which about 1,100 feet of work has been done (fig. 22) 

and several stopes at the surface. It is said that the 

stopes were connected with the tunnel level by means 

of four raises, but it is not now possible to pass from 

one to the other. The tunnel is badly caved in several places. Water draining from it is piped to the 

location indicated by the spring symbol on the map 

and is utilized occasionally to water sheep. The ruins 

of a 40-ton cyanide mill are about 500 feet south of 

the tunnel portal. 

Concerning the production Heikes 60 notes that "in 

1896 and prior to that year 95 tons of ore averaging 

$56 in gold and a trace in silver per ton were treated 

at the Cane Springs mill and shipped to the smelter. 

In 1902 a 40-ton cyanide mill was constructed and 

treated 622 tons with a reported saving of $15 per ton 

in gold. In 1904 the mill was operated again, but the 

results were unfavorable, and the property was praccally abandoned." 

The operations in 1904 resulted in the recovery of 

somewhat less than $20,000 in gold, and the grade 

appears to have been lower than that of the ore previously treated. The total production of the mine is 

about $35,000. So far as known no work has been 

done since 1904. 

The mine workings are in metamorphosed sedimentary rocks belonging to the Manning Canyon and 

Oquirrh formations, which are cut by quartz monzonite. The Manning Canyon formation is exposed 

at the portal of the tunnel and for several hundred 

feet to the south and southwest. It is composed of 

" Kemp. J. F., Notes on Gold Hill and vicinity, Tooele County, Utah: Econ· 

Geology, vol. 13, pp. 257-258, 1918. 

" Heikes, V. C., Ore depOSits of Utah: U.S. Geol. Survey Prof. Paper ill, p. 475, 

1920. 

black shale and dark sandy shale and quartzite. Biotite, andalusite, and tourmaline in microscopic crystals 

are present in many beds. The Oquirrh formation 

overlies the Manning Canyon formation southeast of 

the tunnel portal. North of the tunnel it is in contact 

with quartz monzonite at the surface, but the mine 

workings disclose the Manning Canyon formation beneath it. Sandstone beds form the bulk of the part 

of the formation here exposed. Interbedded with 

N 

50 o 50 100 Feat ~,~'~~~'----~'----~' 

FIGURE 22.-Plan of tunnel level, Midas mine. 

them are several beds of limestone. Both rocks arc 

thoroughly bleached and contain varying amounts of 

silicate minerals, chiefly wollastonite, garnet, and diopside, as the result of metamorphism. 

The beds have a rather general strike west of north 

and dip 30°-45° E. About 1,100 feet south of the 

tunnel portal the succession of beds exposed near the 

mine is terminated by an east-west transverse fault, 

whose throw is somewhat uncertain but appears to be 

more than a mile. Another fault exposed just north 

----'--~-----'~ ....---.... ~-~--
MINES AND PROSPECTS 135 

of the tunnel portal brings the Manning Canyon formation on the south into contact with ths Oquirrh 

formation on the north. This fault may be traced up 

the hill to the east in a direction north of east until 

the crest is reached, where the course swings to east 

of north. The same fault is exposed in the tunnel 

along the hanging wall of a dike of quartz monzonite. 

Its strike is sinuous but averages a few degrees east 

of north. The dip is about 30° W., and this feature 

appears competent to explain the change in course on 

the surface. The throw is estimated to be about 200 

feet, to judge from the position of the upper Manning 

Canyon contact on the two sides of the fault. The 

west side is down thrown. 

Another fault is exposed in the tunnel at the interior inclined shaft. This strikes east of north and 

dips 30°-50° SE. It was not recognized on the surfaee. The relation of this fault to the one just described is not clear. It is probably cut by the westward~dipping fault, because it cannot be conneeted 

directly with the similar eastward-dipping fault in the 

eastern drift north of the shaft. However, if the two 

are the same, it indicates that there has been only a 

small displacement of a reverse character along the 

the westward-dipping fault, which directly opposes 

the stratigraphic evidence. On the other hand, the 

westward-dipping fault cannot be recognized to the 

north, either in the two drifts or in the crosscut connecting them. The writer suspects that the true relations 

between the two faults are that the eastward-dipping 

fault is younger than the bulk of the movement along 

the westward-dipping fault, but that there has been 

a slight renewed movement along the latter (for which 

there is some evidence, as noted below). 

The quartz monzonite near the mine is at the southeastern tip of the triangular outcrop of this rock on the 

south side of Montezuma Peak. The contact at the 

mine trends roughly north and south but is irregular 

in detaiL It is exposed underground near the north 

end of the tunnel workings and there dips 70° E. 

South of the tunnel a broad hook-shaped mass of the 

intrusive extends into the sedimentary rocks. An 

isolated mass of quartz monzonite crops out along the 

ridge east of the mine workings. On the surface its 

shape is that of a flattened triangle, whose base has a 

north-south direction and whose northwestern limb is 

the westward-dipping fault previously described. This 

mass is also exposed in several. places in the tunnel, 

where the fault everywhere forms its hanging wall. 

To the north it apparently has a dikelike form, but to 

the south its lower boundary seems to be very irregular. (See fig. 22.) There has been some movement 

along .the boundary fault after the emplacement of the 

quartz monzonite, as can be seen from the gouge along 

the fault, but the lack of displacement at the contact 

of the fault and the intrusive rock on the surface indicates that this movement must have been very smallfar less than the 200-foot throw shown by the sedimentary rocks. Furthermore, at several other places 

in this region the quarti monzonite has utilized preexistent faults of similar strike and dip to this one during its intrusion. The evidence available therefore 

suggests strongly that the greater part of the movement 

along this fault preceded the intrusion. 

The ore at the Midas mine was found in a bed of 

limestone that has been almost completely replaced 

by silicate minerals. The limestone is interbedded 

with the predominantly sandy beds that here make up 

the Oquirrh formation. The ore body in this bed is 

in the exposure of this formation on the hangingwall side of the westward-dipping fault and cropped 

out on the east side of the gulch in which the tunnel 

is located, the contact with the main mass of monzonite 

being on the west side. The ore body had an average 

thickness of a bout 4 feet and was found in shoots for 

several hundred feet along the strike of the bed. A 

vertical depth of about 100 feet seems to have been the 

limit of the ore body, for it is not exposed on the tunnel 

leveL Locally it is said that it was terminated above 

the level by a fault on whose footwall was found 

"granite", and it seems probable that the fault on the 

tunnel level is the one that terminated the ore. It 

was not possible, however, to examine the bottoms of 

the stopes to ascertain if this view is correct. If it 

is, it would appear that the reported effort to discover 

the faulted portion of the ore bed was foredoomed to 

failure, for, as shown above, the faulting preceded the 

intrusion of the quartz monzonite, which in turn is 

older than the ore. It would probably be more profitable to search for a new ore body in one of the limestone 

beds in the hanging wall of the fault. 

The ore, like that of the Alvara~o and· Cane Springs 

mines, was composed chiefly of wollastonite, in part 

altered to spadaite, and less abundant diopside and 

garnet. Butler 61 also reports vesuvianite. Sulphides 

are not abundant and consist of pyrite and various 

sulphides of copper. Butler notes in addition arsenopyrite. No free gold was observed by the writer. 

The grade of the ore appears to have been somewhat 

higher than the average in the Alvarado and Cane 

Springs mines. 

BONNEMORT 

The Bonnemort claim is about 2,000 feet southeast 

of the C.S. mine and adjoins the Uridine group on the 

northwest. It is owned by the Woodman Estate. 

Gold ore is reported to have been mined some years 

ago from the inclined shaft 350 feet west of hill 5901, 

but the amount and grade are unknown. The shaft is 

now considerably out of repair. 

The country rock consists of sandstone and limestone belonging to the Oquirrh formation. These 

et Butler, B. S., Ore deposits of Utab: U .8. Geol. Survey Prof. Paper 111, p. 479, 

1920. 
136 GOLD HILL MINING DISTRICT, UTAH 

rocks make up the south end of the roof pendant of 

sedimentary rocks in which the U.S. mine is located. 

The sediments in the vicinity of the ore body are almost completely bleached and recrystallized, and many 

of the limestone beds have been altered to silicate 

minerals. In addition to the quartz monzonite on 

each side of the roof pendant, a dike of this rock occurs 

about 25 feet west of the inclined shaft. It strikes 

nearly due north over most of the exposure, but at 

the thicker south end it changes its strike abruptly to 

nearly due east. The portion of the dike with this 

strike does not extend far beyond th.e bend. 

The ore body appears to be similar in several respects 

to that of the Cane Springs and Alvarado mines, but 

the inaccessibility of the workings prevents any close 

comparison. A bed of limestone more or less replaced 

by silicates was mined. This bed strikes N. 5° W. and 

dips 60° E. Gold is said to have occurred in thin 

seams 'within the bed as well as being disseminated 

through it. Factors such as cross fractures that may 

have localized the ore shoot could not be certainly 

recognized at the surface. 

Specimens from the dump that were said to resemble 

the ore consisted of coarsely crystalline white calcite 

in which were scattered abundant laths of wollastonite 

or of dense greenish diopside. Brown zoisite was observed in a few specimens. Specks and patches of 

chalcocite and copper pitch with remnants of chalcopyrite were rather abundant in some specimens. 

Spadaite, which is so wide-spread at the Cane Springs, 

Alvarado, and Midas mines, was not recognized. 

RUBE 

The Rube mine, formerly owned by Lemer Palmer, 

of Gold Rill, is l}f miles northeast of the town on the 

southeast side of Gold Rill Wash. The mine, which 

produces a high-grade direct-smelting gold ore, in 1927 

was developed by a I 50-foot inclined shaft from which 

two levels have been driven, in addition to a group of 

shallow workings east of the shaft. A small compressor and hoist engine were utilized. From April 1921 to 

July 1927,22 shipments of gold ore that averaged more 

than 7 ounces of gold to the ton had been made. 

In May 1932 the mine was sold to the Gold Rill 

Mines, Inc., and since then it has been actively worked. 

At the end of 1932 it was reported that 2 cars of ore 

a week were being shipped, the grade of which ranged 

from $12 to $30 a ton. 

The wall rock shown by the mine workings is a white, 

massively bedded, finely crystalline limestone or dolomite, .locally shattered and iron-stained. It is 

thought to be a portion of the Ochre Mountain limestone that is in part dolomitized. Comparatively little 

alteration to silicate minerals has occurred. The 

strike and dip of the bedding is difficult to determine. 

From several exposures the strike is rather confidently 

thought to be northwest and the dip is with -considerably less assurance considered to be steep to the northeast. 

About a quarter of a mile north of the shaft Prospect 

Mountain quartzite crops out with a nearly east-west 

strike and a moderate northerly dip. The contact 

between the quartzite and the Ochre Mountain limestone is a fault, the movement along which is thought 

to have been chiefly horizontal. The fault is cut and 

displaced by a later fault, which probably extends 

through the eastern part of the Rube No.3 claim, 

although it is possible, as noted on page 80, that the 

offset is due to a northerly fault following Gold Rill 

Wash and concealed by the gravel in the floor of the 

wash: 

Quartz monzonite crops out at the surface about 

1,000 feet west of the shaft and at an equal distance 

to the south, but none has been found in the underground work. The outcrop west of the shaft is at 

the eastern edge of the body of igneous rock along the 

south side of Dutch Mountain; the other is at the 

north end of the main stock. 

The only igneous rock found in the underground 

workings is a thin dike of hornblende andesite that 

forms the hanging wall of the ore bodies. This rock 

in most of the exposures is a dull brownish-gray rock 

composed of a paler fine-grained indeterminate matrix 

flecked with numerous areas of "limonite." It effervesces briskly with dilute hydrochloric acid, not only 

in the numerous veinlets of calcite that streak the rock 

but also in the matrix. At the bottom of the winze 

from the lower level of the western workings much 

fresher material is found. This is a fine-grained grayish-green rock of pepper and salt appearance. It is 

much jointed, with some calcite filling the joints, but 

the microscope shows that the hornblende and plagioclase that are the original minerals have been relatively 

little altered. The rock found on the upper levels, on 

the other hand, has been almost completely replaced 

by calcite. 

The dike ranges in thickness from a few inches to 

5 feet· and has an average though variable strike of 

about east-west and dip of about 60° N. The hanging 

wall is generally a slickensided surface and the contact 

with the footwall sulphide-bearing dolomite is in many 

places a thin crushed zone or joint plane. Locally the 

andesite shows a faint banding parallel to these walls, 

but in other places small apophyses into the walls may 

be found. 

Two small faults cut and offset the dike a few feet 

at the foot of the main shaft, and a third fault appears 

to terminate it about 110 feet east of the shaft on this 

level. The offsets along the two other faults and the 

presence of the dike in the eastern shallow workings 

indicate that the easterly continuation should be found 

south of the present workings. 
MINES AND PROSPECTS 137 

The ore occurs chiefly in two pipelike shoots, known 

as the east and west ore bodies (figs. 23 and 24). The 

hanging wall of both these ore shoots is the hornblende 

andesite dike. The contact of the ore with the dike is 

in the eastern workings, a little ore has been found in 

the hanging wall of the dike. 

The east ore body was the first to be discovered. 

The cross-sectional dimensions of this pipe average 

Br-eccia and silicification 

6'o:r 

Lim,!stone with irregular and 1enttcular masses of Iron oxides 

~ Crushing' and .ilicification: 8 no value 

~ 

EXPLANATION 

F~s-;u;-" 

Hornblend~ '~di~~ite dike. 

Vein infootwall 

20' 

Strike '>;;nd dip 

J!5 0 7S Feet Ll~'~'_'~'~'______-L______ ______~! 

FIGURE 23.-Plan of mine workings, Rube mine. From map furnished by Letller Palmer. 

w. E. 

EAST DRIFT 

\ 

I 

\ 

FIGURE 24.-Longitudlnal section through Rube mine. Furnished by Lelller Palmer. 

sharp. Sulphide-bearing dolomite forms the footwall close to 3 feet in a direction normal to the andesite 

of the ore bodies, and there is generally an abrupt hanging wall and 15 feet parallel to it. The shoot 

contact between the two. Locally, as near the surface rakes 35° W. and has been followed for a distance of 

35311-36--10 

r ~~---~---~------ ~ ..,..­
138 GOLD HILL MINING DISTRICT, UTAH 

135 feet along the rake. The new or west shoot is 

somewhat larg'er in cross section than the eastern one 

and also extends to a greater depth, having been stoped 

for a distance of 230 feet down the rake, which averages 

about 45°. On the bottom level the rake is locally 

extremely variable, being 90° at the level and flatten. 

ing to about 30° in the winze below. It is probably 

a coincidence that the flatter portion if projected 

upward would join the east ore body. Ore of good 

grade was still present in the lowest workings in 1927. 

The hanging wall of the ore bodies is marked by a 

pronounced sheeted zone which in the western ore 

body strikes northwest and dips 60°-80° SW. Similar 

directions are shown by thin bands of sulphides in the 

footwall dolomites. The constant association of the 

sheeting and ore probably has a genetic significance, 

but there are several places where apparently similar 

jointing is not accompanied by a concentration of gold. 

Northeast of the eastern workings there is a promi. 

nent outcrop of brecciated dolomite with quartz. This, 

like the main ore zone, has an approximate east.west 

strike. Both might be considered to have been formed 

at about the same time as the large transverse fault 

farther north and to represent sympathetic fractures. 

The ore mined has several different facies. The 

most abundant variety so far has been a brownish 

fine-grained rock of siliceous appearance but having a 

notable content of calcite, as shown by its effervescence 

with dilute acid. Pseudomorphs of "limonite" after 

pyrite and of anglesite and cerusite after galena and 

veinlets of cerusite are abundant, and locally unaltered 

galena may be seen. Native gold in small partly 

crystalline aggregates is found in the iron and lead 

oxidation minerals and in one specimen was superposed on a "limonitic" coating. In a specimen of a 

heavy grayish-green fine·grained rock from the east 

ore body pyromorphite and plumbojarosite cemented 

by supergene quartz were found. 

In thin sections quartz and calcite are found to be 

the most abundant minerals. The quartz grains are 

full of calcite inclusions and in most places contain 

numerous liquid. inclusions, each with a tiny gas 

bubble. Calcite also occurs in larger grains and as 

veinlets cutting the rock. Its cleavages are usually 

deeply iron·stained. In a specimen of very rich ore 

from the east ore body sericite was abundant and was 

veined by anglesite and cerusite, as well as calcite. In 

this specimen the native gold was localized in the 

anglesite. 

Ore of this type is seen to pass, in the lower portion 

of the western workings, into much less oxidized material. This is a blue-gray fine-grained rock locally 

splotched by brown oxidation products that in places 

shows a faint banding. Galena and less abundant 

pyrite are only partly altered, and locally native gold 

may be found either in galena or in the matrix, 

although most of it occurs in the supergene minerals. 

The banding is shown by the microscope to be due 

to varying proportions of calcite and quartz, which 

still form the bulk of the rock. Veinlets of coarsergrained clear calcite are abundant and in some places 

are closely associated with the gold and sulphides. In 

other places, however, the metallic minerals are without visible relation to the veinlets and appear as 

isolated areas in the matrix, surrounded by a rim of 

coarser-grained and clear calcite. 

A third type of ore was found in the western ore 

body just above the second level, in the position 

marked "sulphide ore" on figure 24. The hangingwall portion of this ore is composed chiefly of shattered 

crystalline pyrite that is cut by quartz and calcite 

veinlets containing small amounts of galena, chalcopyrite, and sphalerite. The remainder of this ore 

contains abundant molybdenite with some pyrite in a 

greenish or black fine-grained matrix, which the 

microscope shows to be composed of calcite, talc, 

slightly pleochroic muscovite, scapolite near meionite, 

zoisite, and two varieties of chlorite. This facies of 

the Rube ore appears to offer a sort of connecting link 

with the gold ore of the Alvarado, Midas, and Cane 

Springs mines. 

Sulphide minerals are present in the footwall limestone or dolomite of the ore bodies. They are associated with relatively small 1uantities of quartz and 

sericite and locally contain some gold, although not 

enough to warrant mining at the time of examination. 

The metallic minerals recognized in the two specimens 

of this rock studied under the microscope inelude 

native gold, pyrite, pyrrhotite, deep-red and colorless 

sphalerite, galena, and arsenical boulangerite. Sphalerite is by far the most abundant. 

The grade of the ore mined varies from place to 

place in the stopes,>-.,The carloads shipped up to June 

1927 ranged in gold c~tent from 2.83 to 24.42 ounces 

to the ton and averag~d over 7 ounces. The silver 

content is generally lowe;r and is roughly proportional 

to the lead content, rang\ng from 2 to 3 ounces to the 

ton for each percent of l~ad. One shipment from the 

east ore body carried mqre than 6 percent of arsenic. 

The presence of antimony and small quantities of 

bismuth and tellurium mthe ore has been proved by 

analysis. One picked specimen, which the writer did 

not see, is reported by Mr. Palmer to have contained 

7 percent of bismuth. 

WILSON CONSOLIDATED 

The Wilson Consolidated mine is on the northeast 

side of Clifton Flat, about 2,500 feet south-southwest 

of the prominent jasperoid hill at an altitude of 6,455 

feet north of the road to Clifton and immediately 

west of hill 6266. The headquarters of the company 

is in Salt Lake City. Production from the property 

appears to be eonfined to several small shipments of 

high·grade ore in 1914 and 1917. Relatively little 

......... 
r

I I 

MINES AND 

work has been done since 1917. The mine workings 

aggregate less than 500 feet, chiefly in the form of 

crosscuts and shallow winzes. The vertical range of 

the workings is abo.ut 75 feet (fig. 25). 

The rocks exposed in the mine workings are metamorphosed sandstones and limestones belonging to 

the central facies of the Oquirrh formation. About 

200 feet west of the portal of the tunnel these beds are 

separated from limestones thought to belong to the 

western facies of the same formation by a normal 

fault of unknown but probably considerable throw. 

The most pronounced effect of the metamorphism 

upon the sediments of the central facies is a nearly 

• 

• 

r 

complete bleaching to white or pale cream color. 

There has also been a marked mineralogic change in 

many of the rocks, and the resulting hornfels is in 

many places difficult to distinguish from bleached 

quartzite. In the two specimens of hornfels examined 

under the microscope diopside and orthoclase had been 

abundantly developed. Bedding can be distinguished 

with difficulty in this series, owing in part to the metamorphism and in part to the widespread shattering. 

So far as observed the bedding strikes a little west of 

north and dips about 30°-40° W. The prevailing 

A 

SHAFT 

\ 

\, , 

" 

... .... 

N 

SECTION ALONG LINE A-B 

1'''-..1 

Fault 

LEVEL 

TUNNEL 

pT.:;a;N 

50 0 250 Feet ~I~I~I~I_I~I--__ ____ ______L-____ __~I 

FIGURE 25.-Sketch plan IlJld section of Wilson Consolidated mine. 

PROSPECTS 139 

dip in the region southeast of the mine, however, is to 

the east, and it is thought that the westward dip may 

be a local feature peculiar to the zone bordering the 

large fault immediately to the west. Igneous rocks 

are almost lacking in the immediate vicinity of the 

mine. A dike of volcanic breccia was observed about 

50 feet from the portal of the adit. This is thoroughly 

crushed and much altered, chiefly to chlorite with 

minor amounts of a clay mineral. Locally the texture has been preserved in some of the rock fragments, 

and there is little doubt that the dike is related to the 

outcrops of volcanic rocks that occur along the borders 

of Clifton Flat in this region . 

The bismuth-gold ore is found in what is locally 

known as a vein but what appears to be nothing more 

than a bed of coarsely crystalline bleached limestone. 

Like the barren wall rocks, it dips about 30° W. The 

contacts of the bed are sharp but show no signs of 

movement or replacement. The limestone has a maximum thickness of 6 feet at the south end of the drift 

on the tunnel level but is usually nearer 3 feet in thickness. The ore-bearing bed is cut by at least nine 

north-south normal faults. These dip 30°-70° E. and 

all have throws of less than 50 feet. Of the two faults 

._--------------------------------------------------------------­
140 GOLD HILL MINING DISTRICT, UTAH 

that are shown in the tunnel level, the throw along the 

more easterly appears to be negligible and that along 

the more westerly to be about 25 feet. The throw 

along the fault that cuts off the limestone in the winze 

connecting the tunnel and middle level must be about 

15 or 20 feet, as the three small faults exposed on the 

middle level displace the ore zone as it is exposed in 

the raise from the south drift on this level scarcely 

more than a foot apiece. The throw along the fault 

that terminates the ore at the bottom of the winze 

leading to the bottom level is easily determined as 

being close to 15 feet by reason of the exposure of the 

faulted segment in the crosscut to the west. This 

exposure of the ore zone is also cut by a fault striking 

north of west and dipping steeply to the south. The 

throw along it is about 5 feet. Both the fault and the 

ore zone are. cut off a short distance to the west by 

another north-south fault dipping 45° E. Thethrow 

along this fault as well as along another a short distance t.o the west that has a similar strike but dips 

70° E. is somewhat uncertain. If the southward-dipping fault which is exposed to the west of t.he more 

westerly of these two faults and which is cut off by it 

is the same as the fault of similar dip to the east, the 

combined throw along the two faults amounts to about 

25 feet. On the other hand, the ore zone is reported 

to be reached in the shaft at a depth of 30 feet from 

the surface, and no faults were recognized between the 

shaft and the faults in question-facts which require 

a combined throw of about 50 feet. This figure is 

perhaps the closer to the truth, because to correlate 

the two southward-dipping faults would require horizontal movement along either or both of the northsouth faults, and if this were admitted, the divergent 

figures for the vertical displacement could be readily 

explained. 

The ore contains gold, bismuth, and a little tungsten. 

The chief gangue mineral is quartz, which is preEtmt 

either as euhedral crystals 1 millimeter or less in diameter, distributed through the limestone, or as veinlets 

of very fine grained allotriomorphic material. In one 

specimen from the south drift on the tunnel level the 

limestone is also cut by veinlets of orthoclase. This 

mineral was not found in any of the other ore specimens, however. 

The ore minerals observed were native bismuth, 

bismuthinite, bismutite, and scheelite. Copper sulphides and a l~ad-tungsten mineral, probably stolzite, 

are also reported from this mine by Butler.52 Bismuthinite and its oxidation product, bismutite, are by far 

the most abundant. The sulphide is found as rounded 

specks as much as a quarter of an inch in diameter embedded in the limestone. Much of the bismutite forms 

pseudomorphs after bismuthinite, as is shown by the 

preservation of cleavage lines, but a moderate amount 

" Butler, B. S., Ore deposits 01 Utah: U.S. Geol. Survey Prof. Paper 111, p 482, 

1920. 

is clearly transported, for it is found also in veinlets of 

supergene opal and chalcedony and along cleavage 

planes of the calcite matrix. Native bismuth was 

found in only one specimen, which was taken from 

the stope leading to the surface from the east end 

of the tunnel level. The mineral was found in the 

center of a grain of bismuthinite. Scheelite was also 

recognized in only one specimen, which was taken from ' 

the open cut about 50 feet south of the stope to the 

surface. Its occurrence is similar to that of the bismuthinite. Scheelite is reported to have been rather 

abundant in the raise from the south drift on the 

middle level. Native gold also occurs in the ores, but 

none was found in the specimens collected. The two 

stoped areas were mined chiefly for their gold content. 

Butler 63 notes that the gold is closely associated with 

bismuthinite, and in one of his specimens the writer 

observed gold adjacent to several copper minerals. 

The grade of the ore is variable. The distribution 

of gold and scheelite is apparently limited to rather 

small shoots in the vein. No figures are available as 

to the grade of the scheelite-rich portions, but the 

shoots of gold ore seem to have averaged somewhat 

less than 1 ounce to the ton. Bismuth minerals, 

however, are rather widely distributed throughout the 

ore zone, although the amoUht is far from being constant. The only figures as to grade that are available 

apply to a shipment of 4.33 tons of concentrates that 

contained 12.43 percent of bismuth. This lot presumably came from the stope from the surface to the 

tunnel leveL It contained about $9 a ton in gold. 

These figures are probably considerably higher than 

the average of the vein. 

VEIRS CONTAINING CliIIEFLY QUARTZ AND 


JDTALLlC SULPHIDES 


LUCY L 

The Lucy L mine is in Lucy L Gulch about 2 miles 

south-southeast of the town of Gold Hill. It includes 

a group of seven patented claims that are owned by 

the Lucy L Mining Co. The Wilson Brothers, of Salt 

Lake City, have directed the past operations of the 

company. Exploration of the gold-quartz ore body 

had been effected prior to Kemp's visit in 1908, and 

the tungsten deposit on the property was being developed at the time of Butler's examination in 1912. 

The property was idle during the period of the writer's 

field work. It is developed by about 1,300 feet of 

workings from two adits (pI. 13), in addition to several 

shallow surface pits. No figures are available as to 

the production, but it is believed that a few small lots 

of gold ore and possibly one or more of tungsten ore 

have been shipped. 

The most prominent formation in the vicinity of the 

Lucy L mine is the Ochre Mountain limestone. Massively bedded members of this formation make up 

03 Butler, B. S., op. cit., p. 482. 
r 


PLATE is 

i 

GEOLOGICAL SURVEY 

A 

o Gold.bearing 60~lcrU!lhed rock '.' . \t, '"""I' \ 0 7. +-.,......1::. qu' A. '1_, '-. ''''''''...... It'f'r, 

I I I I """ ........ _ f'Of' 

' ...... '-. I'l7a' Crushed dar!< '-':-.. t/o/') porphy~ ~. 

EXPLANATION 

Quartz outcrop on level 

-

Stope 

Fault 40·,.,­

Strike and dip 

Tunnel level 

Lower level 

Lower level 77'below 

70~.' tunnel level 

~ .., ~v "> .. _ .. 

._._.. -..,v ~- to 

\7 1r'.J \v .., V 

V 

Feet 

N 

r 

PROFESSIONAL P.\PER 177 

£1.5946' 

r..... I I 

I I I I , I 

, I 

'I I Tungsten

! \ workings 

I \ 

I I

I I 

I ) 

~_/ 

PLAN OF WORKINGS, LUCY I, MINE. 

.. _---------------------------­
MINES AND 

the greater part of the hill (altitude 6,125 feet) on 

whose slopes the mine workings are found. The limestone is shattered and locally bleached but shows 

practically no development of silicate minerals. 

Strikes and dips are almost impossible to determine 

by reason of the thickness of the beds and the widespread shattering. Those that were obtained, however, 

suggest that minor warping or folding has been 

widespread. 

Two other sedimentary formations are exposed on 

the lower slopes of the hill. One of these is the Manning Canyon formation, which crops out in the gulch 

on the south side of the hill and is also seen at the 

portal of the south tunnel. In the tunnel the formation is composed of badly crushed and crumpled 

black shale, with thin rusty sandy partings. On the 

surface southeast of the portal reddish quartzites are 

also found in the formation. About 20 feet from the 

portal the black shale is succeeded by a zone of 

intensely crushed shale in which are included blocks of 

Ochre Mountain limestone, and this in turn is followed 

by 60 feet of the massive limestone (pI. 13). A nearly 

vertical normal fault again exposes the breccia. These 

relations clearly require that the breccia zone represent 

a thrust fault, and on page 73 it was indicated that 

it is an eastern continuation of the Ochre Mountain 

thrust. The other formation is found on the eastern 

slope of the hill in and near the northern of the two 

tunnels. Here relatively thin bedded rocks crop out, 

which resemble closely the metamorphosed sandstones 

and limestones of the central facies of the Oquirrh 

formation that are exposed a short distance to the 

north. A specimen of a metamorphosed sandstone 

taken from a point near the tunnel portal was composed largely of quartz that was presumably recrystallized, as' the grains were rimmed by fine dustlike 

material. Scattered throughout the quartz were 

smaller crystals of diopside and less abundant grains 

of orthoclase. Veinlets of tremolite cut the rock. 

Other beds, presumably with a higher original content 

of calcium carbonate, have been altered to garnetdiopside rock or to one composed chiefly of wollastonite. These beds are exposed throughout the greater 

part of the northern workings and must therefore 

underlie the Ochre Moulltain limestone, which crops 

out at the surface. The contact between the two is 

not well exposed on the surface, but, in view of the 

presence of the thrust in the southern tunnel, it seems 

certain that this contact represents the same fault. 

Quartz monzonite terminates the sedimentary rocks 

on the north and east, and small lenticular masses 

of the same rock occur on the south and west. The 

mine workings show that the quartz monzonite also 

underlies areas where sedimentary rocks are exposed 

at the surface, and it seems rather certain that igneous 

rock is present at no great depth beneath the whole 

hill. The upper surface of the quartz monzonite must 

be rather flat, although in detail it is very irregular 

PROSPECTS 141 

'q: 

(fig. 26). Two dikes are cut by the northern tunnels, 

for example, that do not appear at the surface, although 

the section suggests that they must join the main mass 
142 GOLD lULL MINING DISTRICT, UTAH 

of the intrusive not much more than 100 feet below 

their apices. A specimen of relatively unaltered 

quartz monzonite taken from the western workings 

from the southern tunnel is of the normal type of 

biotite-quartz monzonite but shows some slight metamorphism by the presence of a few idiomorphic diopside crystals. Near the ore bodies the rock is as a 

rule considerably altered. A specimen from the southern tunnel workings about 75 feet east of the shaft has 

been largely replaced by garnet, diopside, and hornblende, and these minerals in turn have been partly 

altered to quartz, sericite, and calcite. Another specimen adjacent to the ore body on the bottom level of 

the southern workings has been bleached to a dull 

cream-colored rock in which the igneous texture can 

be recognized only locally. The dark minerals have 

been completely and the feldspars partly replaced by 

calcite, sericite, and quartz. Butler 64 noted that adjacent to the tungsten deposits on the southeastern 

slope of the hill diopside, a green hornblende, carbonate 

minerals, epidote, and a few crystals of allanite have 

been introduced. Underground the quartz monzonite 

locally includes blocks of the sedimentary formations. 

One of the Manning Canyon formation was observed 

in the long crosscut southeast of the shaft in the 

southern workings, and another, probably of the 

Oquirrh formation, which was found to be calcitetremolite rock, was found at the extreme east end of 

these workings. 

Two kinds of ore have been mined from the Lucy L 

property. These are gold-bismuth ore and tungstencopper ore. The largest body of the gold-bismuth ore 

was found in the south workings about 225 feet from 

the portal of the tunnel and took the form of a lenticular mass of quartz 50 to 75 feet long and 10 feet in 

maximum thickness. The ore body has a crescent 

shape in horizontal section, with the concavity to the 

northwest. The dip is 40°-50° NW. Quartz monzonite forms both walls of the ore. On the tunnel 

level it is separated from the ore on the hanging-wall 

side by a well-defined slip and on the footwall side by 

a zone in which dark silicates are abundant. Both 

of these features are absent on the bottom level, where 

the quartz monzonite walls are thoroughly bleached. 

Locally minerals resembling kaolinite and halloysite 

have been developed in this rock as a result of weathering. On this level the dimensions of the ore body 

appear to be considerably smaller. 

The ore is relatively simple mineralogically. It is 

composed almost entirely of quartz, which has been 

thoroughly shattered. The fracture planes in almost 

all places have been filled with a dark-brown iron oxide, 

with which yellow-brown jarosite is only locally associated. The microscope shows that the quartz has 

been formed at two 'stages. The earlier: quartz is 

" Butler, B. S., Ore deposits of Utah: U.S. Geol. Survey Prof. Paper 111, p. 477, 

1920. 

glassy and coarsely crystalline and ~nds to be euhedral. It forms the greater part of the ore body, The 

younger quartz is found chiefly in the interstices of 

the older crystals and is generally separated from them 

by a layer of chalcedony fibers. It is very fine grained. 

Locally this fine-grained material is found in relatively 

large areas where it has clearly replaced the older 

quartz. Sericite occurs in association with much of it. 

The metallic minerals observed were bismuthinite 

and native bismuth (both largely oxidized to bismutite), pyrite (also oxidized), and native gold. 

Specimens containing these minerals were not abundant, but the impression was gained that they occur 

either in or near the areas of fine-grained quartz. All 

the gold seen was embedded in bismutite. Kemp 66 

has described a gold telluride from this mine, but none 

was found by the writer. A copper mineral was also 

probably present in the primary ore, as a small amount 

of malachite was observed. The bismuth minerals 

and gold are of rare occurrence in the quartz body 

and appear to be limited to relatively small shoots 

that are roughly outlined by the stoped areas shown 

in plate 13. No figures are available as to the content 

of gold or bismuth in the shoots. 

Gold-bearing rock is also reported to occur in two 

zones near the west end of the bottom level of the 

northern workings. (See pI. 13.) This is a shattered 

grayish-green rock in which large cleavage plates of 

calcite may be seen that are interrupted by dark minerals. There are a few pseudomorphs of "limonite" 

after pyrite and some copper stains. The microscope 

shows in addition to calcite, green hornblende, garnet, 

and apatite, together with numerous veinlets of finegrained quartz. No gold was observed in the slide. 

Tungsten-copper ore is found in a vein about 400 

feet south of the north tunnel portal. The vein has a 

width of 4 feet or so and is exposed for a length of about 

100 feet by a series of shallow pits in which it strikes 

about north and has a nearly vertical dip. The walls 

are both of quartz monzonite and are roughly parallel to 

the intrusive contact, which is less than 50 feet distant 

to the west. Some slickensides may be. seen along the 

walls. The ore extended downward only about 15 

feet. The eastern workings from the south tunnel 

underlie the northern extension of the vein about 100 

feet below the surface but show no sign of similar 

mineralization. 

The ore consists chiefly of dark silicates in a scant 

matrix of calcite. The calcite is coarsely crystalline 

and, though largely replaced by the silicates, is readily 

recognized by the reflection of light from the large but 

interrupted cleavage surfaces. Locally the calcite is 

relatively unreplaced, and in these areas the adjoining 

silicates show good crystal faces. Pyrite and chalcopyrite are more abundant in these calcite areas than in 

.. Kemp, 1. :r.• Notes on Gold Hill and vicinity, Tooele County. western Utah: 

Econ. Geology, vol. 13, p 260, 1918. 

-
MINES AND 

the rock rich in silicates. The distinguishing feature 

of the ore is the presence of crystals of yellowish-gray 

scheelite, which may reach an inch in length. 

The silicate minerals present include andradite 

garnet, diopside, epidote, titanite, green hornblende 

(partly altered to actinolite), and orthoclase. There 

appears to be a definite sequence in their formation, 

and the scheelite appears to belong to one of the early 

stages. Quartz and calcite veinlets with associated 

sericite and chlorite cut all the other minerals. In 

addition to the minerals cited, axinite and zoisite were 

noted in specimens collected in 1912 by Butler from 

this property. 

Picked specimens of the ore are rich in scheelite or 

in chalcopyrite or its oxidation products, but the small 

extent of the deposit and the rather erratic distribution 

of the valuable minerals in it have prevented any 

recent development. It is thought that a small lot of 

tungsten ore was shipped some years ago from this 

property, but no data as to the grade were obtained. 

A similar mineral assemblage but without any 

scheelite is exposed at the surface contact of the quartz 

monzonite by a prospect pit west of north from the 

tungsten workings and also within the sedimentary 

rocks in the northern tunnel. The copper present in 

these occurrences is far too low for them to be of value. 

BOSTON 

The Boston claim is south of the Linco]n Highway 

about 6,000 feet east-southeast of the summit of 

Gold Hill. It is said to be owned by the Boston-Utah 

Mining Co., whose headquarters are at Los Angeles, 

Calif. No shipments are known to have been made 

from the property. 

Quartz monzonite forms the wall rock of the vein 

on the claim, which has been explored by several 

shallow surface cuts and by an inclined shaft of no 

great depth. To the north the vein strikes N. 40° W. 

and dips about 45° SW. Toward the south the strike 

swings to nearly due north and the dip steepens. The 

vein is offset for a few feet by several minor faults and 

is apparently terminated to the south by a larger one. 

The vein filling is from 1 to 3 feet thick and consists 

of crushed quartz monzonite together with quartz, 

arsenopyrite, and oxidized minerals of iron, lead, and 

arsenic. Locally arsenopyrite and scorodite are present 

to the almost complete exclusion of the other minerals. 

At the surface the results of all stages of the alteration 

of the sulphide to scorodite may be observed. The 

arsenopyrite is reported by W. M. Lamb, of Gold Hill, 

to carry $14 in gold to the ton. Near the south end of 

the vein, at the inclined shaft, some lead-silver ore is 

said to occur. Specimens of plumbojarosite or the 

related arsenic compound may be seen on the dump 

and presumably were the source of the lead. 

NEW YORK 

The New York claim, on the southwest side of Dutch 

Mountain about half a mile north of altitude 5,963 feet 

PROSPECTS 143 

on the Ferber Road, is owned by Messrs. Bailey and 

Delmonico, of Gold Hill. In 1927 some assessment 

work was being done on the claim in developing a small 

mass of lead-arsenic ore that was found along a fault 

that separates the Pottsville portion of the Oquirrh 

formation from higher beds in that formation. The 

ore exposed was entirely oxidized and appeared to 

consist chiefly of scorodite. Assays of the ore were 

said by Mr. Bailey to show a content of $4.40 in gold 

and 12 ounces of silver to the ton and 8 to 9 percent of 

lead. 

SILVER ... GOLD MINING CO. 

The Silver & Gold Mining Co., Inc., whose headquarters are in Spanish Fork, Utah, owns five claims 

about a mile northeast of the Western Utah mine and 

east of Calico Hill. So far as known no shipments 

have been made from the claims. 

In 1926 the company was engaged in exploring a 

vein that cropped out in limestones and sandstones of 

the Oquirrh formation about 2,000 .feet east of the summit of Calico Hill. The sedimentary rocks are very 

close to the northern contact of the quartz monzonite 

stock, and the igneous rock was cut at a shallow depth 

in the inclined shaft that was being sunk on the 

vem. 

The vein occupies a fault fissure, the movement along 

which occurred before the mineralization. The throw 

along it amounts to about 10 feet, as is shown by the 

displacement of the quartz monzonite contact. The 

dip is about 55° W. at the surface but steepens to 65° 

after it enters the igneous rock. In the portion of the 

vein enclosed by sedimentary rocks the vein is as 

much as 4 feet in width and is almost completely oxidized. Quartz, scorodite, and oxidized minerals of 

iron and lead are the most prominent minerals in this 

portion. In the quartz monzonite the vein is much 

thinner (3 to 12 inches) and has been much less affected 

by oxidation. Pyrite, arsenopyrite, galena, and sphalerite were recognized in sulphide-bearing specimens 

from this part of the vein. The operators reported 

that the vein as exposed in June 1927 had an average 

content of $10 in gold and 3 ounces in silver to the ton. 

In places high gold assays were obtained. 

MASCOT 

The Mascot group of claims, in the quartz monzonite 

area north of Overland Canyon and west of Barney 

Reevey Gulch, is owned by Frank J. Guilmette, of 

Gold Hill. A small amount of development work has 

been done on several quartz-sulphide veins that strike 

about north and dip on the average 45° W. The metal 

present is chiefly arsenic, in the form of both arsenopyrite and scorodite, but locally there are small shoots 

of lead ore. On the Mascot No.2 claim a small pegmati tic pipe is exposed, which is reported to contain 

small amounts of scheelite. The surface dimensions 

of this pipe are about 5 by 3 feet. 

l 
-----------

144 GOLD HILL MINING DISTRICT, UTAH 

MONTE DEL RET 

The Monte del Rey group of four patented claims 

is in Hopkins Gulch a short distance northwest of the 

Midas mine. It is owned by P. H. Robinson, of Gold 

Hill. A long cross-cut tunnel has been driven westward in quartz monzonite from a point about 100 

yards south of the spring to cut several veins that are 

exposed on the surface. The veins contain chiefly 

arsenic minerals but locally carry small quantities of 

lead minerals. No production is known from the 

group. FORTUNA 

The Fortuna group of three claims is in Hopkins 

Gulch about three-quarters of a mile northwest of the 

Midas mine. The claims are owned by Mrs. Emma 

C. Thompson, of Denver, Colo. Several surface cuts 

and pits have been made on a quartz-arsenopyrite 

vein in quartz monzonite similar to the other veins in 

this region. Locally it contains small quantities of 

lead minerals. No shipments have been made from 

the property. BONANZ.A 

The Bonanza group of claims, owned by Mrs. Emma 

C. Thompson, of Denver, Colo., covers most of the 

ridge north of the Cyclone mine. In 1926 it was under 

lease to Frank J. Guilmette, of Gold Hill. So far 

as known, no shipments have been made. 

The ore is found as small shoots in a wide shear zone 

in quartz monzonite that has a general strike of about 

N. 20° E. and dips 65° W. The ore 'shoots, which are 

locally as much as 5 feet in width, contain chiefly 

arsenic ore, in the form of arsenopyrite and scorodite, 

but in some places a large proportion of the ore is 

composed of lead and zinc minerals. Mr. Guilmette 

was developing one such shoot in 1926. 

The 170-foot tunnel on the claim exposes a dike of 

dark porphyry that has been cut by numerous minor 

faults. CYCLONE 

The Cyclone mine is about 1,600 feet south-southeast 

of U.S. Mineral Monument No.9, in Barney Reevey 

Gulch, on the south side of Montezuma Peak. The 

mine takes its name from the Cyclone claim, which is 

one of the six claims owned by the Engineers Development Co., of Salt Lake City. This company acquired 

the claims in 1925 and since that time has established 

a camp and done a moderate amount of development 

work. The workings consist of an inclined shaft on 

the vein, from which, at a depth of 80 feet, a drift has 

been extended to the north more than 400 feet. Several 

raises extend upward from the drift, and the inclined 

shaft has been extended down the dip an unknown 

distance. The vein has also been explored by a tunnel 

whose portal is north of the shaft collar. Shipments of 

lead-silver ore are reported to have been made from 

the property in 1926. 

Only two formations are exposed in the vicinity of 

the mine. Quartz monzonite underlies most of the 

surface. It does not differ notably from exposures of 

this rock elsewhere. The quartz monzonite is cut by 

a dike of granite porphyry, a light greenish-gray rock 

that weathers in many places to shades of brown. This 

rock contains numerous phenocrysts of quartz 1 to 2 

millimeters in diameter and less abundant phenocrysts 

of biotite and feldspar. The microscope shows that 

the feldspar phenocrysts include both orthoclase and 

albite. The groundmass of the rock is very finely 

crystalline and is made up of qua.rtz, feldspar, and 

biotite. The dike strikes a little east of north and 

dips 50° W. 

The quartz vein that contains the ore minerals 

follows the hanging wall of the granite porphyry dike. 

It is not continuous, stretches of quartz and sulphides 

alternating with stretches in which a foot or more of 

gouge takes the place of the vein. The alternation 

appears to be correlated with changes in the strike of 

the vein. In general, the portions with a nearly 

north-south strike are occupied by gouge, and those 

that strike east of north contain quartz and sulphides. 

Similar variations along the dip of the vein are exposed 

in the raises from the level. In at least one place the 

barren stretches may be correlated with a local steepening in the dip of the vein. 

Gouge is also found on either wall of the quartz or 

on both. About 300 feet north of the shaft, for 

example, there is a few inches of gouge between the 

vein and the footwall granite porphyry and about a 

foot of gouge and crushed quartz monzonite on the 

hanging wall. The gouge contains fragments of quartz 

and sulphides and was reported to contain in one 

place 17 percent of arsenic. 

Adjacent to the vein the granite porphyry has been 

considerably altered. The feldspar phenocrysts have 

been changed to a soft claylike mineral and the 

groundmass to a fine-grained aggregate of quartz and a 

little sericite. The quartz monzonite hanging wall, on 

the other hand, has been but little affected. 

The drift from the inclined shaft has disclosed five 

shoots of quartz-sulphide ore. The most southerly of 

these is the longest, extending about 100 feet northward from the shaft. In the succeeding 200 feet to 

the north three small shoots are exposed, two of them 

having lengths of about 15 feet and one of 30 feet. 

The fifth shoot starts about 300 feet north of the shaft 

and has a length of about 60 feet. The thickness of 

the shoots reaches a maximum of about 3 feet, but the 

average thickness is between 18 inches and 2 feet. 

The vein filling, as shown on the drift from the shaft 

consists of a mixture of quartz and sulphides in which 

the proportion of each varies, locally the one or the 

other predominating. The sulphides recognized are 

pyrite, arsenopyrite, galena, chalcopyrite, aikinite, and 

sphalerite. Small quantities of an iron-rich dolomite 

replace the sulphides locally. In most places the sul­
MINES AND PROSPECTS 145 

phides are fine-grained and intermixed, but ina few 

places concentrations of a single mineral are found in 

which the grain size is considerably greater. 

A series of 11 samples taken at 5-foot intervals 

along the southern ore shoot showed the following 

variations in content: 

Gold (average) _____ ounces to the ton__ 0.03 

Silver (average) ______________do____ 6 

Lead _______________________ percent__ 0.4-8.2 

Copper_______________________do____ 0.5-1.7 

Zinc ________________________do__ -- 0.5-3.8 

Arsenic_______________________do____ 0.5-7.3 

The ground-water level corresponds closely with the 

level of the drift, but there is comparatively little 

sign of oxidation in the vein at this horizon. The 

bottom of complete oxidation was found to be about 

35 feet above the drift level in the shaft and about 30 

feet above the level in a raise 300 feet north of the 

shaft. About 100 feet north of the shaft, at a point 

that corresponds with the position of a stream channel 

on the surface, the ore is partly. oxidized and contains 

much greenish-blue chalcanthite. Near the surface 

yellow-brown powdery jarosite and plumbojarosite, 

both of which probably contain a little arsenic, are 

abundant. 

SUCCESS 

The Success mine is about 2 miles southeast of the 

Western Utah Copper Co.'s Gold Hill mine and 6,000 

feet due west of bench mark 5060 on the Lincoln Highway. It is owned by W. F. Peters, of New York City, 

but in 1926 the property was being worked under lease 

by D. C. Scott, of Park City, Utah. In 1927 Messrs. 

Sevy & Wilkins, of Gold Hill, were lessees. Several 

shipments of lead-silver ore have been made from the 

property. In 1920 a lot of 94 tons of ore .contained 

0.06 ounce of gold and 32.3 ounces of silver to the ton, 

1.55 percent of copper, and 8.96 percent of lead. 

Smaller shipments were also made in 1926 and 1927, 

but their grade is not known. 

The country rock at the mine is quartz monzonite, 

which is rather thoroughly crushed and altered. 

Surface exposures of the rock near the mine are 

relatively few. In a specimen taken from the footwall of. the vein all the original minerals of the rock, 

except quartz and the accessory minerals, have been 

almost completely replaced by sericite, calcite, and 

chlorite. 

The ore is found in a quartz vein cutting the igneous 

rock. As exposed in the inclined shaft on the vein, 

the strike is northwest and the dip 30°-45° W. In the 

shaft the thickness of the vein ranges from a few inches 

to about 4 feet. There has been considerable movement after the formation of the vein, which has resulted 

in the presence of gouge on either or both walls. During the visits to the mine in both 1926 and 1927 the 

greater part of the workings from the shaft were 

inaccessible, but on one short drift on the vein north 

of the shaft considerable variations in the strike of 

the vein were observed. The writer is informed that 

the vein was cut off at one place by an east-west fault 

and that the faulted segment was never found. 

Although the fault was not observed in the mine, the 

offsets of the dike east of the mine workings as shown 

in plate 2, suggest that there has been a relative shift 

to the east on the south side of the fault. 

Oxidation of the ore minerals is complete at the 

surface, jarosite and plumbojarosite being abundant. 

Sulphides are found in the shaft about 90 feet below 

the collar (about 45 feet vertically), although the 

ground-water level is at 125 feet (about 65 feet 

vertically). The primary ore consists of white coarsely 

crystalline quartz, pyrite, arsenopyrite, galena, sphalerite, and tennantite. Polished sections show the 

presence also of thin veins of a carbonate mineral. 

As in other veins of this type in the district, both the 

ratio of the sulphides to the quartz and their relative 

proportions to one another vary considerably from 

place to place. Locally there are concentrations of 

cleavable black sphalerite that has a distinctly nonmetallic appearance when slightly weathered. 

SPOTTED FAWN 

The Spotted Fawn group of claims, now located 

under the name of the Silver Hill group, is in Spotted 

Fawn Canyon, on the east side of Dutch Mountain. 

+83' AT 

so· SURFA~e 

N 

VEIN t+54' 

0' 

PORTAL 

FIGURE 27.-Plan of tunnel and surface workings on north side of gulch, Spotted 

Fawn mine. 

The Gold Hill Mines CO., of Salt Lake City, is the present owner. Shipments amounting to 78 tons were 

made from the property during 1901-17. These had 

an average content of 0.038 ounce of gold and 25.1 

ounces of silver to the ton and 18.1 percent of lead. 

The main workings on the group are on the northeast 

side of the canyon, where a tunnel has been driven 

beneath two shallow shafts (fig. 27). Some work has 
146 GOLD BILL MINING DISTRICT, UTAH 

also been done on the southwest side of the canyon, 

in another shallow shaft from which some short drifts 

have been driven. A well-built bunkhouse and a 

machine shop in which an air compressor is housed 

are situated just below the mine workings. These 

buildings may be reached by a wagon road following 

the bottom of the canyon. This road is passable by 

automobiles to a point within a quarter of a mile of 

the mine. 

The mine workings are in much faulted Middle 

Cambrian rocks that lie a short distance beneath the 

Ochre Mountain thrust. The ore bodies on both sides 

of the gulch occur in thin-bedded limestones, locally 

dolomitized, but in the tunnel only the Busby quartzite was observed. South and east of the mine workings 

the contact between the limestone and the quartzite 

is a fault striking west of north that is a branch of the 

Spot~ed Fawn fault, the main branch of which lies 

about 500 feet west of the tunnel portal. The branch 

fault, however, cannot explain the presence of quartzite 

in the tunnel immediately beneath limestone exposed 

on the surface. To account for these relations (see 

p. 82) a nearly flat fault must intervene between the 

two. Such a fault is not readily recognized on the 

surface. The breccia exposed in the top 10 feet of the 

raise near the north end of the tunnel probably represents the fault breccia, and the fault must therefore 

dip gently to the south. Several nearly horizontal 

fractures that cut the quartzite beds exposed in the 

tunnel must be subsidiary to the major fault. 

The ore is found along fissures striking east of north 

and dipping 50°-65° W. It consists of rather coarsegrained white quartz with some barite and local concentrations of galena in which are found small amounts 

of pyrite and other sulphides. Oxidation of the galena 

to anglesite and cerusite in most places has been rather 

complete, but unaltered sulphide nodules are not uncommon. The flat fault that must separate the quartzite from the limestone must also limit the ore downward, 

for no evidence of comparable mineralization was found 

in the tunnel. It was not asc~rtained whether the lack 

of ore in the tunnel was the result of movement along 

the fault subsequent to mineralization or whether the 

fault was formed earlier than the ore and the unfavorable character of the quartzite prevented any 

deposition of ore minerals. 

WESTERN UTAH EXTENSION COPPER co. 

The group of 15 patented claims owned by the Western Utah Extension Copper Co. extends to the southeast from the open cut of the Western Utah Copper Co. 

The ownership is reported to be the same as that of 

the Pole Star Copper Co. Superficial explorati'on has 

been carried on at several places on the group, but on 

only one claim, the Helmet, has any considerable 

amount of underground work been done. In 1917 

and 1918 nearly 200 tons of ore was shipped from this 

claim. It had an average content of 0.026 ounce of 

gold and 5.4 ounces of silver to the ton and 4.08 percent of copper. The property appears to have been: 

idle since 1918. 

The workings on the Helmet claim consist of amain 

tunnel and several higher levels, on all of which some 

Dike 

SHAFT 80" 

50 0 SO 100Feet !L..;!L..;!L....!...'IL..;!'---_...J...!_-...J' 

FIGURE 28.-Plan of tunnel level, Western Utah Extension Copper Co. 

stoping has been done. Nearly 1,000 feet of drifting 

has been done on the tunnel level (fig. 28), and from 

it two interior shafts have been sunk. The tunnel 

at an altitude of 5,751 feet is more than 250 feet lower 

than the summit of the east-west ridge beneath which 

it is driven. 

N 
MINES AND PROSPECTS 147 

The claim is near the central part of the quartz 

monzonite stock, and this rock forms the walls of the 

ore. Both underground and on the surface a dark 

greenish-gray altered porphyry is exposed as a dike 

cutting the quartz monzonite. It is about 4 feet wide 

and strikes east of north. 

The ore is found in a quartz vein that strikes approximately north and has a normal dip of 60°-70° W. 

The fissure occupied by the vein is clearly a fault fissure, for it cuts and displaces the porphyry. This is 

clearly shown in the tunnel about 150 feet from the 

portal, where the dike is present in the hanging wall 

of the vein but not in the footwall. The exposures of 

the dike on the surface indicate that the throw along 

the fissure is normal and amounts to about 50 feet. 

The vein and the dike are cut by another fault about 

500 feet south of the portal of the tunnel. This fault 

strikes about N. 20° W., dips to the west, and is marked 

by considerable brecciation. North of its intersection 

with the vein a crosscut shows 10 feet of gouge along 

the fault, the footwall of which dips 30° and the hanging wall about 85°, As the vein approaches the fault 

its strike swings to northwest and its dip flattens to 

30°. The offset due to the fault on the tunnel level 

amounts to about 40 feet, the portion of the vein in 

the footwall of the fault being to the north. This 

implies either that the fault is reverse or that it is a 

normal fault with a large horizontal component. 

The ore is almost completely oxidized from the surface to the tunnel level. It consists of quartz, altered 

quartz monzonite fragments, and various copper, iron, 

and arsenic minerals. The thickness of the vein ranges 

from a few inches to 3 feet, but in some of the thicker 

portions the ore mineralS occupy only part of the vein. 

In a few places sulphide minerals had been preserved. 

Those recognized were arsenopyrite, pyrite, and sphalerite. The oxidized ore minerals appear to have been 

chiefly copper pitch and a deep-brown fine-grained 

scorodite. In many places, however, there are striking 

concentrations of blue-green chrysocolla, bright-green 

clinoclasite, and olive-green olivenite. The sulphide 

that was the source of these copper minerals was not 

recognized in the few specimens of unoxidized material 

that were collected. 

At several places on this group of veins prospecting 

has disclosed veins in which arsenopyrite and scorodite 

are the most abundant constituents. 

CLIMAX 

The Climax group of 12 patented claims is in Rodenhouse Wash. The greater part of the work on the 

group has been done a short distance west of the prominent hill at an altitude of 5,675 feet on the north side 

of the wash. J. P. Gardner, of Sarasota, Fla., is 

reported to be the owner. The property has been 

idle for several years. A partly caved vertical shaft 

filled with water and the remains of a shaft house are 

about the only signs of former activity. Custer 88 

reports that the shaft was 150 feet deep and that from 

it 250 feet of drifts and crosscuts had been driv.en. 

He further records the shipment of two cars of ore that 

contained 29 ounces of silver to the ton and 27 percent 

of lead. 

Chloritized and sericitized quartz monzonite forms 

the wall rock of the ore bodies. East of the vertical 

shaft this rock is cut by prominent quartz and quartz 

carbonate veins that strike nearly north and dip at 

rather low angles to the west. So far as could be told 

the ore does not extend through or beyond them. 

The vertical shaft is sunk on a vein striking N. 82° 

W. From the scant exposures on the surface and from 

small amounts of ore on the dump, the vein filling 

appears to have consisted of quartz, pyrite, arsenopyrite, galena, and sphalerite. The sphalerite appears 

to have been particularly abundant. These minerals 

are all cut by veinlets of a brown-weathering siderite. 

SOUTHERN CONFEDERATE 

The patented Southern Confederate claim, one of 

the oldest in the district, is on the high ridge southeast 

of the town of Clifton, the end of the wagon road at 

an altitude of 6,742 feet marking the present camp 

site on the claim. It is owned by the Southern Confederate Mining Co., Inc., of Salt Lake City, and in 

1926 was under lease to T. E. Wessell. Much of the 

ore utilized by the old Clifton smelter is reported to 

have come from this property. Small shipments have 

been reported for the years 1918, 1919, and 1926. 

These shipments have averaged about 30 percent of 

lead and 30 ounces of silver to the ton. Small quantities of zinc, copper, and arsenic are also present. 

The ore is found in a shear zone as much as 20 feet 

in width that strikes about N. 50° E. aJtd dips 75°-80° 

SE. The wall rock is quartz monzonite altered to a 

dense greenish rock in which only small quartz grains 

can be recognized with the hand lens. The microscope 

shows that the alteration consisted of both sericitization and the introduction of fine-grained quartz and 

chlorite. In this ore zone lenses of lead ore as much as 

2 feet in width and, exceptionally, 50 feet in strike 

length have been found. A shaft on the vein is said 

to reach a depth of 150 feet, but less than 50 feet of it 

is now accessible. 

The ore minerals in these lenses consist almost en .. 

tirely of the oxidized lead minerals anglesite, cerusite, 

and plumbojarosite, of which the anglesite is by far 

the most abundant. Unoxidized remnants of finegrained galena are not uncommon, but no other sulphides were recognized. Limonite pseudomorphs after 

pyrite are found in many places in the wall rock. 

Coarsely crystalline quartz is the chief gangue mineral. 

Small quantities of azurite and malachite are distributed throughout the ore. 

ea Custer, A. E., Deep Creek, Clifton mIning dIstrict, Utah: Eng. and Min.101D'•• 

vol. 103, p. 920. 1917. 
148 GOLD HILL MINING DIS'!'RICT, UTAH 

There is abundant evidence of movements along 

the vein since the ore was deposited. These have 

formed coarse breccias in the portions of the vein rich 

in quartz, and gouge walls to the ore shoots were noted 

in several places. 

RED JACKET 

The Red Jacket claim is immediately north of the 

Southern Confederate claim, less than half a mile 

southeast of Clifton. The owner of the claim is said 

to be R. W. Young, and in 1926 J. H. Allen and associates were at work under a lease and bond. Like the 

Southern Confederate, the Red Jacket is reported to 

have furnished ore to the old Clifton smelter. The 

only recent production known is that made by the 

lessees in 1926. The grade of the lead-silver ore 

shipped is not known. 

As on the adjacent claim, the ore is found in a shear 

zone in altered quartz monzonite. The shear zone 

is about 4 feet wide, strikes northeast and dips steeply 

to the southeast. The workings on the vein are on the 

east side of the ridge line and consist of several tunnels 

and cuts on the vein. In one of the tunnels a winze 

was sunk on the vein and, at a depth of about 180 feet, 

is said to have struck an eastward-dipping fault that 

terminated the ore. This winze could not be examined 

at the time of this survey. 

. The ore is found in lenses in the shear zone and consists of coarse white quartz with galena and a little 

pyrite, together with oxidation products of the sulphides. Anglesite is the most abundant of these and 

forms the bulk of the ore. Other lead minerals present 

include cerusite, plumbojarosite, and, near the surface, 

rather considerable amounts of green crystalline mimetite. Small orange-colored crystals of wulfenite are 

also found in the oxidized ore. 

COPPER QUEEN MIDLAND MINING CO. 

The Copper Queen Midland Mining Co., whose 

headquarters are at Grantsville, Utah, owns a group 

of unpatented claims on the southwest side of Montezuma Peak, a short distance east of benchmark 5855, 

at the head of Overland Canyon. Prospecting has 

been done on several veins, chiefly by shallow cuts or 

pits. On one of the veins, however, a tunnel more 

than 600 feet long has been driven. Small shipments 

of ore were made from this group of claims in 1916, 

1918, and 1919, which averaged 17.4 ounces of silver 

to the ton, 0.56 percent of copper, and 15.35 percent 

of lead. 

The ore is found within the small triangular outcrop 

of quartz monzonite that lies to the west of and is 

connected with the larger intrusive mass on the south 

side of Montezuma Peak. The quartz monzonite contains both biotite and hornblende, in addition to the 

feldspars and quartz, and does not differ in any respect 

fI:om the rock that forms the greater part of the main 

stock. Both the southern and northwestern borders 

of this small intrusive area are controlled by older 

faults and, because of this, three different sedimentary 

formations are in contact with the igneous rockthe Oquirrh formation on the northwest, the Manning 

Canyon formation on the east, and the Ochre Mountain limestone on the south. 

The ore occurs in veins within the quartz monzonite 

that strike N. 15°-30° E. and dip 25°-40° W. Several 

of these veins have been developed, but the most 

persistent one appears to be that followed by the 

Midnight tunnel, whose portal is about 3,000 feet east 

of benchmark 5855. The vein is exposed throughout 

the length of the tunnel, a distance of 620 feet. The 

width of the vein ranges from 1 to 5 feet. As in other 

veins of this sort in the district, a moderate thickness 

of gouge is usually present on either the hanging wall or 

footwall, or both. In a few places nearly east-west, 

steeply dipping faults cut the vein and displace it for 

distances as great as 5 feet. In many places the quartz 

monzonite wall rock has been rather completely altered 

to sericite as much as 5 feet from the vein. Locally, 

however, the alteration was much less intense, and 

specimens taken less than a foot away may be essentially unaltered. 

In the tunnel much of the ore is unoxidized and is 

seen to consist of white coarse-grained quartz, in 

which are fragments of sericitized wall rock, and a 

variable content of sulphides. Among these, arsenopyrite, pyrite, galena, sphalerite, and chalcopyrite have 

been recognized. The proportions and total quantity 

of these sulphides differ in different parts of the vein. 

Veinlets of a brown-weathering carbonate cut across 

the quartz and sulphides. Optical tests prove this to 

contain about 75 percent of the FeCOa molecule. In 

the surface workings oxidation of the sulphides has 

been nearly complete. In some places the oxidation 

products have migrated into fractures in the wall 

rocks, giving the appearance of spurs from the vein. 

Jarosite and plumbojarosite are among the most 

abundant of these later minerals. 

CASH BOY (MAMMOTH) 

The Cash Boy group of four claims is on the northeast slope of hill 5696, east of the Success mine. Two 

of the claims are owned by L. H. Sevy and C. H. Abercrombie, of Gold Hill, and the other two (comprising 

the old Mammoth claims, owned by J. P. Gardner) are 

under lease and bond to them. Some ore was being 

mined at the time of visit in 1926, and it is reported 

that several shipments had been made in the past. 

The only one of which there is record was made in 

1915 and consisted of 4 tons, which contained 0.02 

ounce of gold and 26 ounces of silver to the ton, 0.8 

percent of copper, and 13 percent of lead. 

Two shallow shafts 2,200 feet apart have been sunk 

on shear zones in quartz monzonite that contain shoots 

of lead-silver ore. At the northern shaft an ore shoot 

strikes N. 80° W. and dips 60° SW. At the southern 

-----!.

-

MINES AND PROSPECTS 149 

shaft the strike of the ore is N. 50° W. and the dip 

40°-60° S. It is not known if the two shear zones 

exposed in the shafts are connected, but the strikes 

recorded are similar to those shown by a continuous 

porphyry dike that crops out a few hundred feet west 

of both localities. 

The ore shoots in the shear zones have relatively 

small dimensions and appear to be limited to regions 

in which abundant quartz has been introduced. At 

the surface the ore is completely oxidized, but in 

specimens on the dumps some sulphide minerals were 

observed. Galena, sphalerite, arsenopyrite, and pyrite 

were recognized in these specimens. The oxidized 

minerals include a lead-bearing jarositelike mineral, 

angle site, cerusite, and locally considerable amounts of 

orange-colored wulfenite. 

NEW BALTIMORE 

The New Baltimore patented claim covers the 

slopes of hill 5625 in Rodenhouse Wash, about half a 

mile west of the Climax mine. It is owned by J. P. 

Gardner, of Sarasota, Fla., but in recent years has been 

worked in a small way under lease by Swan Moline. 

Several small shipments have been made since 1923. 

One of 22 tons in that year contained 0.02 ounce of 

gold and 53 ounces of silver to the ton and 47 percent 

of lead and is representative of the other shipments. 

The developments consist of shallow surface cuts and 

shafts. 

The wall rock is the rather thoroughly altered quartz 

monzonite that is found over so much of the region 

drained by Rodenhouse Wash. Chlorite, sericite, calcite, and quartz have largely replaced the original 

minerals of the igneous rock, although in many places 

the alteration has preserved textures characteristic of 

the quartz monzonite, especially outlines of the old 

feldspar crystals. In one of the tunnels a dark altered 

porphyry was seen, but it could not be recognized on 

the surface. 

The ore is found as thin lenses in an east-west zone 

of fissuring that dips almost vertically. The ore shoots 

in this zone range in thickness from a few inches to a 

foot or so and are succeeded by lower-grade material 

within short distances along thl( strike. Galena, showing relatively little alteration to anglesite, forms the 

greater part of the vein filling in the ore shoots. Near 

the surface it is found as rude nuggets coated with 

powdery calcite. Small amounts of pyrite, arsenopyrite, and quartz are present with the galena and 

have largely replaced it in the vein beyond the ore 

shoots. Locally the galena has been more completely 

oxidized, and in such places the ore consists of anglesite, 

cerusite, plumbojarosite, mimetite, and descloizite, 

together with small amounts of copper minerals. The 

fissure zone, together with the ore shoots, is cut in 

several places by north-south faults that dip to the 

west. The throw on all of them is small, but they are 

accompanied by a considerable amount of gouge. In 

one place an eastward-dipping fracture intersected the 

vein, and it is said to have contained some very rich ore. 

BIRD 

The Bird claim, which is unpatented, is owned by 

Ollie Young, of Clifton. It adjoins the Southern 

Confederate on the northeast and encloses the continuation of the fissure on that claim. A small lot of 

ore from the claim was included in a shipment by 

Young in 1926 that also contained ore from others of 

his properties. 

The relations of the ore are the same as those in the 

Southern Confederate. A drift tunnel driven southwestward on the vein showed about 2 feet of ore in 

1926. 

SHAY 

The Shay claims are near Goshute Spring, about a 

mile east of Montezuma Peak. In 1926 some prospecting was being done on a northeastward-striking 

vein in altered quartz monzonite that contained 

stringers of lead ore in a mixture of quartz and altered 

wall rock. The ore exposed was completely oxidized 

and was composed chiefly of a mineral resembling 

plumbojarosite. Numerous small orange-colored crystals of wulfenite were also observed in the ore. 

GOLD HILL STANDARD MINING CO. 

In 1926 the Gold Hill Standard Mining Co. owned 

18 unpatented claims east of the town of Gold Hill. 

Several exploratory workings were being driven in that 

year on the Max No.1 and Max No.2 claims of the 

group, to expose a number of short linked veins in 

quartz monzonite that had a northwest strike and a 

dip of 30°-60° SW. The vein filling consisted of 

quartz, altered wall rock, galena and its oxidation 

products, and oxidized iron and arsenic minerals. The 

distribution of the several minerals is very erratic. In 

some places lenses of solid galena a foot wide and 

several feet long may be found, and in other places 

galena is entirely absent, and arsenopyrite and scorodite are the only metallic minerals present. Much of 

the galena has not been oxidized, but locally it has 

been converted to anglesite, plumbojarosite, and 

wulfenite. The galena-rich ore is said to contain 2 

ounces of silver to each percent of lead. 

GOLD BELT 

The Gold Belt claim, owned by W. F. Cummings, 

of Gold Hill, covers the small outcrop of Prospect 

Mountain quartzite that occurs at bench mark 4293, 

on the edge of the Great Salt Lake Desert. The 

bedding at this locality strikes N. 30° E. and dips 30° 

SE. The ore has replaced a breccia zone striking 

N. 60° E. and dipping 50° SE. It consists of white 

coarsely crystalline quartz with local splotches of 
150 GOLD HILL MINING DISTRICT, UTAH 

galena and minor amounts of other sulphides. It 

is only partly oxidized. 

PAY ROCK 

The Pay Rock group of three claims is on the south 

side of Spotted Fawn Canyon, a short distance west of 

its entrance. In 1926 it was owned by L. H. Sevy and 

C. H. Abercrombie, of Gold Hill. In that year work 

was being done on the ridge line a short distance west 

of summit 5729. Here a thin streak of cerusite and 

plumbojarosite was found along a brecciated bedding 

plane in the Prospect Mountain quartzite. Its width 

ranged from a fraction of an inch to several inches. 

UNDINE 

The Undine group of four unpatented claims and a 

fraction is half a mile southeast of the U.S. mine and 

half a mile north of the Lucy L. It is owned by W. 

M. Lamb, of Gold Hill. There are several relatively 

shallow workings on the claims that are grouped in 

two areas-north and northwest of hill 6081 and north 

and east of hill 5882. Three or four shipments of ore 

have been made from the group, but at the time of 

visit only assessment work was being done. 

The rocks exposed on the claims are metamorphosed 

sandstones and limestones of the Oquirrh formation and 

quartz monzonite. The sedimentary rocks are found 

in relatively small and very irregular patches capping 

the higher summits. The igneous rock surrounds them 

and crops out in all the valley bottoms. These 

relo.tions indicate that in this region the present surface approximates the original upper contact of the 

qU8:rtz monzonite. The sedimentary rocks are for the 

mo~st part poorly exposed, but many of the limestone 

bed!J have clearly been replaced by silicate minerals. 

Ga~et, wollastonite, amphibole, and a green muscovite were recognized in the field, and a careful study 

would doubtless show many others. Chlorite and 

sericite are abundant in places in the quartz monzonite. Weathering has been more intensive here than 

in many other places, and this in part accounts for 

the poor exposures. A large part of the outcrops of the 

sedimentary rocks and the nearby igneous rocks have 

been converted to a white powdery calcite that on 

casual inspection appears to be a clay mineral. Locally 

this is veined by dense reddish opal. 

The most extensively explored ore body is that about 

700 feet northeast of hill 6081. This is in a small patch 

of sediments at their contact with the quartz monzonite. The ore body is a nearly flat tabular mass and 

appears to be a. bedded replacement deposit extending 

outward on both sides of a nearly vertical north-south 

fissure. Copper minerals, for the most part copper 

pitch and chrysocolla, are concentrated along the 

fissure, but away from it the limestone bed appears to 

have been replaced chiefly by magnetite, which is now 

partly oxidized to "limonite" and nontronite. A 

hand sample of the magnetite is reported by Mr. 

Lamb to have assayed 0.96 ounce of gold to the ton, 

and he believes that most of the gold in the two 

shipments made from this deposit was also contained 

in magnetite. One shipment, said to be a carload, he 

reports to have carried $8 a ton in gold and 7~ percent of copper and the other, of 12 tons, $9 a ton in 

gold and 8 percent of copper. 

A different type of deposit is found to the southeast 

near the blacksmith shop, about 250 feet north of 

hill 6081. This is a thin quartz vein in quartz monzonite. It strikes N. 5° W. and is nearly vertical. 

The width varies, but the maximum observed was 14 

inches. The vein appears to be moderately persistent 

along both strike and dip, as it has been followed to 

a depth of about 50 feet by two vertical shafts 50 

feet apart, which did not reach its end. The vein 

filling consists of rather coarsely crystalline white 

quartz containing sporadic bodies of a black sulphide

whICh . M. N. Short, of the GeologICal .'Survey, determined to be an arsenical tetrahedrite. Less common 

are patches of galena. The tetrahedrite is for the 

most part altered to green and blue oxidation products. 

Mr. Lamb states that a shipment of 3 tons returned 

$300 a ton, largely in silver, at a time when that 

metal was selling at $1 an ounce. Specimens of the 

sulphide alone were said by him to run as high as 409 

ounces of silver to the ton. 

Northwest of these deposits two veins have been 

prospected east of hill 5882. Both are in quartz monzonite just below the contact with the sediments. 

The more northerly vein strikes N. 15° W. and dips 

55° W. It consists of sheared quartz monzonite impregnated with oxidized copper minerals, chiefly copper pitch and chrysocolla. Remnants of chalcopyrite 

may be seen in the copper pitch. The quartz monzonite in the hanging wall of the vein is iron-stained and 

streaked with white powdery calcite. A shipment 

thought to have been made from this prospect in 1918 

yielded 0.03 ounce of gold and 5.8 ounces of silver to 

the ton, 3.05 percent of copper, and 1.02 percent of 

lead. The second vein, about 100 feet to the south, 

strikes N. 60° W. and dips about 70° SW. As exposed 

it is 2 to 3 feet in width and is filled by arsenopyrite, 

almost completely altered to green scorodite with a. 

relatively small content of quartz. No other metallic 

minerals were observed. 

The prospects north of hill 5882 lie along a ja.speroid 

vein that follows a thin highly altered dike that cuts 

the sedimentary rocks. This vein is reported to carry 

about $1 a ton in gold. 

REA 

The workings on the Rea claim are on the floor of 

Accident Canyon just below the cabin at an altitude 

of 6,051 feet. In 1927 the claim was staked by Messrs. 

Parker & Hager, of Gold Hill, but at one time it was 

owned by the Brewer Gold & Copper Mining Co. 

----"- -----------------­
MINES AND PROSPECTS 151 

The small amount of development work is reported to 

have been done about 1900. No shipments are known 

to have been made from this claim. 

The ore occurs along a fault between the Madison 

limestone and the Woodman formation. At the bottom of the canyon the fault strikes N. 550 E. and dips 

almost vertically, but a short distance up the side of 

the canyon where the Woodman formation is on both 

sides of the fault, the dip is much lower. (See pI. 

7,0.) The ore consists of veinlets and irregular masses 

of quartz and coarsely crystalline calcite, which have 

replaced the wall rocks and with which is associated 

silver-bearing tetrahedrite. Material rich in this sulphide is said to have assayed 150 ounces of silver to 

the ton. Most of the ore now exposed is rather completely oxidized, malachite and azurite being the two 

most abundant secondary minerals. 

CHRISTMAS MINING CO. 

The Christmas group of 12 patented claims is near 

the eastern border of the quadrangle a little over 2 

miles east-northeast of the Western Utah mine. So 

far as known, the company, whose headquarters is at 

Salt Lake City, has made only one shipment of ore, a 

lot of 11 tons produced in 1917 containing an average 

of 0.08 ounce of gold and 18.8 ounces of silver to the 

ton, 0.5 percent of copper, and 4.4 percent of lead. 

The claims cover a series of outcrops of the Oquirrh 

formation that are irregularly embayed by quartz monzonite. To the north the exposures of the Oquirrh 

formation are terminated by the eastward extension 

of the Pool Canyon transverse fault, north of which is 

the Prospect Mountain quartzite. Much of the surface in the vicinity is covered by the gravel slopes that 

extend down to the Great Salt Lake Desert. The 

Oquirrh formation in this region consists of metamorphosed limestone and dolomite with some interbedded 

quartzite, which have been assigned to the central 

facies of the formation. 

Several prospect pits have been sunk in the western 

part of the group on quartz stringers that follow shear 

zones. The· quartz contains local concentrations of 

galena and tetrahedrite, and these two minerals are 

also found embedded in the wall rocks. Considerable 

quantities of barite are also present in the walls of 

some of the veins. 

The main workings seem to have been about half a 

mile farther east, where a vertical shaft about 100 feet 

deep has been sunk in a small outcrop of the Oquirrh 

formation that is entirely surrounded by gravel. The 

shaft was sunk on a narrow quartz vein, in which galena 

and tetrahedrite are locally abundant. At the surface 

the ore appears to have been considerably oxidized. 

VEINS WITH OARBONATE OR SlJLPHATE lIIIINlmALS IN THE GANGUE 

TROY 

The old Troy claim is on the east side of Rodenhouse 

Wash, about 2,000 feet south-southwest of the Climax 

mine. In 1926 it had been restaked by Perry Erickson 

and Amy Hicks under the name of Sam K. No.!. 

The claim is underlain by quartz monzonite and covers 

the western part of a zone of quartz and quartz carbonate veins which are thought to mark a belt of reverse 

faulting in the quartz monzonite. (See pp. 89-90.) 

One of these veins striking N. 75 0 W. and dipping 

400 N., composed almost entirely of quartz in which 

are numerous fragments of altered quartz monzonite, 

has been rather extensively explored on the surface, as 

a result of the supposed discovery some years ago of a 

pocket of rich gold ore. Doubt as to the actual presence of gold in the vein was expressed by some of the 

older prospectors in the district, as the time of discovery coincided with a period in which "high-grading" 

was prevalent at the Cane Springs and Alvarado mines. 

No other occurrences of gold ore are known from either 

this vein or other similar veins. Small specks of a 

mineral thought to be chalcopyrite were observed in 

a few specimens of the ore. 

IMMENSE 

The Immense claim, owned by P. H. Robinson, 

encloses a large mass of jasperoid projecting into the 

quartz monzonite about 2,000 feet southwest of 

Minnehaha Spring. The jasperoid mass strikes nearly 

north and dips about 500 E. It appears to have been 

formed by a replacement of a projecting arm of the 

Oquirrh formation into the intrusive. No information 

was obtained regarding the presence of any valuable 

minerals in the iasperoid. 

ARSENIO REPLAOElIONT BODIES 

GOLD HILL MINE OF WESTER~ UTAH COPPER CO. 

Location, history, and development.-The Gold Hill 

mine of the Western Utah Copper Co., sometimes 

called the Western Utah mine, hits produced a large 

part of the copper, lead, and arsenic ore credited to 

the Clifton district. It comprises a group of nine 

claims and fractions, more or less overlapping, that 

cover the northwest slope of Gold Hill, about 1* miles 

east of the post office. Two of the claims were among 

the first staked in the district and appear to have made 

a small production of gold ore and oxidized silver-lead 

ore. It is said that some placer mining was done on 

the hill slope also. The activity at the Alvarado and 

Cane Springs mines in the early nineties resulted in 

renewed activity on. these claims, and some gold ore 

from them was treated at the Cane Springs mill. Then 

followed a period of inactivity until 1906, when title 

to the group of claims was taken over by the Western 

Utah Copper Co., of which Duncan McVichie, of 

Salt Lake City, was the guiding spirit. 

In the succeeding 10 years a considerable body of 

copper ore was developed above the 150-foot level 

and smaller bodies of lead-silver ore on a lower level. 

No ore was shipped in these years, however. Production began early in 1917, shortly after the com· 

pletion of the Deep Creek Railroad, the construction 
--------

152 GOLD HILL MINING DISTRICT, UTAH 

of which was largely effected by those interested in 

this mining company. 

Shortly thereafter control of the company passed to 

Frank G. Rowley, of Providence, R.I. After the first 

year lead surpassed copper in value in the ore shipped. 

The discovery that the ore contained a large percentage 

of arsenic resulted in the continued operation of the 

mine in the face of a decreasing content of silver, copper, 

and lead, and a considerable tonnage of arsenic ore was 

shipped from 1923 to 1925. Much of this ore was 

shipped at a flat rate per ton, without regard for its 

metal content other than arsenic. The drop in the 

price of arsenic early in 1925 resulted in the virtual 

shutdown of the mine and after a short period during 

which lead ore was shipped company work ceased 

and the production of the mine has since been confined 

to small shipments by lessees. 

Production from Western Utah mine, 1917-29 

[Figures furnished by C. N. Gerry, U.S. Bur. Mines] 

I Silver Copper Lead Ore (tons) Gold I (ounces) (ounces) (pounds) (pounds) 

1917_______ 32, 023 421. 00 1150, 767 1,715, 189 371,418 1918_______ 15, 893 233. 99 86, 716 420, 610 1, 062, 432

1919_______ _13, 787 197.33 49, 825 181, 786 652, 980 1920_______ 39,297 64. 70 83, 581 81,928 958, 189 

192L______ 11,557 150.24 22, 479 3,172 329,866 1922_______ 74 1. 00 819 616 4,178 1923_______ 13,049 7. 00 38,487 28,363 254, 854 1924_______ 32,780 82. 50 145,034 3, 144 1, 753, 698 1925_______ 12, 802 131. 60 107, 480 48,101 1, 659, 613 

1926_______ 122 .90 891 1,681 22, 506 1927_______ 76 1. 30 345 1,033 5, 121 1928_______ 145 .72 792 480 42,117 1929_______ a33 1. 16 2,033 : _________ 

• Dump are. 

The amount of arsenic recovered from the ores is 

not definitely known, but it appears to have been 

between 7,000 and 8,000 tons of metallic arsenic. 

Two shafts, one vertical and one inclined, provide 

access to the deeper workings, on which the greater 

part of the mining was being done during the time of 

examination. Both of these have been sunk from the 

adit or 300-foot level, whose portal is at an altitude of 

5,579 feet. The vertical shaft is near the portal and 

is 400 feet deep. From the bottom of it the 700-foot 

level has been driven. (See pI. 15.) This level is also 

cut by the inclined shaft, which is 700 feet farther 

south. From the inclined shaft the 400, 600, and 760 

foot levels have also been driven. From the 760-foot 

level a winze about 150 feet deep has been sunk and a 

short drift, known as the 900-foot level, turned from 

it. Above the 300-foot level are several tunnels, 

designated on the mine maps as the 80-foot level, 

150-foot level, etc. Only one of these, the 150-foot 

level, is at present extensive. The remainder have 

been largely destroyed by the caving operations in the 

glory hole that now marks the original outcrop. 

Geology.-The geology in the vicinity of the mine is 

epitomized by plate 14, which is in brief a series of 

interconnected plans and lo'ngitudinal and cross 

sections. 

The oldest of the formations shown in this diagram 

and also the most important economically is the Ochre 

Mountain limestone, which in most places forms the 

walls of the ore bodies. On the surface, north of the 

300-foot level portal, the limestone is thick-bedded, 

white, and recrystallized. South of the tunnel portal 

and in most of the exposures underground much of the 

limestone has been either altered to silicate minerals 

or partly replaced during the oxidation of the ore 

minerals. White bladed wollastonite is the most 

common of the silicate minerals, but a greenish-brown 

garnet is also widely distributed. In some places 

diopside and zoisite are locally abundant. In many 

places, however, crystalline limestone may be found 

in close proximity to the ores, and such specimens of 

this as were tested proved to be remarkably free from 

impurities. The limestone beds have a rather constant 

northwest strike. Near the surface they dip steeply 

to the east or even vertically, but on the lower levels 

of the mine the dip is 45° or less, because of the approach to a synclinal axis to the ·east. (See p. 77.) 

The next younger formation near the mine is the 

Manning Canyon formation, which occupies the 

eastern slope of the ridge beneath which lie the mine 

workings. It is made up of dark quartzite and black 

shale and is not exposed underground. 

Between the Manning Canyon formation and the 

Ochre Mountain limestone there is a wide belt of 

jasperoid that has been called in previous reports 

quartzite or silicified limestone. It is reddish brown 

on weathered surfaces and forms the prominent jagged 

outcrops that make up the ridge line. Much of the 

rock has the appearance of a breccia, owing to the 

presence of several generations of quartz, each of 

which has a slightly different texture and color. Vugs 

lined with crystalline quartz are common, and in 

several places green chalcedony and plates of barite 

are present. In a few places fragments of limestone 

were, found embedded in it. Thin sections show that 

the rock has a typical jasperoid texture, and this, 

together with the megascopic evidence,'leaves little 

doubt that the rock is the result of replacement by 

silica along the limestone-shale contact. Butler 67 suggested that the contact was a fault, and the evidence 

indicating that it is one is mentioned on page 77. 

The thickness of the jasperoid is not exactly known. 

As shown on plate 14, it appears to be in excess of 100 

feet, but this figure may be too large by reason of the 

difficulty in determining the exact location of the 

debris-covered contact with the Manning Canyon 

formation. 

Underground the continuation of the surface exposure of the jasperoid is seen on the 300- and 700-foot 

67 Butler, B. S., The are deposits of Utah: U.S. Geol. Survey Prof. Paper 111, 

p. 481, 1920. 
U. S. GEOLOGICAL SURVEY 

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U.S. GEOLOGICAL SURVEY 

PROFESSIONAL PAPER 177 PLATE 15 

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IZI SHAFT WINze RAISE 
MINES AND PROSPECTS 153 

levels. On both levels the rock was cut by the easterly crosscuts from the vertical shaft. On the 300-foot 

level only a small amount of the jasperoid was penetrated by the crosscut before a drift into the footwall 

limestones was started. On the 700-foot level, however, the contact of the jasperoid with the limestone 

was followed for several hundred feet. Here the contact is extremely sharp. The strike is N. 35°-55° W. 

and the dip 35°-45° E. The dip of the jasperoid, 

like that of the limestone beds, must decrease down­ i 	 ward, for the average dip obtained by connecting the 

exposures on the 300-foot and 700-foot levels is 60° E., 

and at the surface the dip is even steeper. l Smaller masses of jasperoid are also found both on 

the surface and underground. On the surface a short 

spur from the main mass extends northwesterly from 

the mineral monument on peak 5901. On the 300-foot 

level similar material containing abundant residual 

calcite is found in the easterly crosscut north of the 

main ore body. This is directly beneath the spur on 

the surface and may be a continuation of it. .Also 

on the 300-foot level typical jasperoid containing barite 

and some oxidized copper minerals has been developed 

at the contact between quartz monzonite and limestone 

near the end of the long combined drift and crosscut 

west of the ore body. Similar relations were observed 

on the 600-foot level. There appears to be a close 

relation between this contact jasperoid and the quartztetrahedrite veins in the limestone nearby. In these 

two places part of the jasperoid appears to have 

replaced quartz monzonite, rather than limestone. 

Quartz monzonite occupies the largest area in the 

vicinity of the mine. It shows no unusual features 

here. Underground much of the rock is seen to be 

altered, rarely to jasperoid as noted above, or widely 

to a quartz-sericite-calcite aggregate, in which the 

outlines of the old crystals, particularly the feldspars, 

are commonly preserved. 

The quartz monzonite is a part of the main Gold 

Hill stock and almost completely surrounds the block 

of sedimentary rocks in which the mine is located. 

North of the open cut it has a rather regular contact, 

with the Ochre Mountain limestone, which strikes~ 

more northwesterly than the jasperoid, with the result 

that the width of the limestone outcrop increases to 

the north. South of the open cut, however, the igneous rock cuts off the limestone and at the surface 

is in contact with the jasperoid. The termination of 

the limestone is not the result of the convergence in 

strike of the jasperoid and the limestone and quartz 

monzonite contact but is rather accomplished by the 

penetration of the limestone by three blunt wedgeshaped dikes of the igneous rock. 

The most westerly of these dikes is the widest at 

the surface and appears to widen rapidly downward. 

The dip of its eastern or hanging-wall side, however, 

is greater than the average dip of the jasperoid, so 

36311-86-11 

that limestone is exposed on the bottom levels of the 

mine directly beneath places on the surface where 

the intrusive is in contact with jasperoid. This same 

conclusion may be reached from the fact that limestone is found in the long Ida Lull tunnel, to the south. 

The middle dike is about 30 feet wide at the surface 

and ends northward somewhere within the open cut. 

Near the surface it dips steeply to the east, but between 

the 300- and 400-foot levels it is nearly vertical, and 

below the 400-foot level it must reverse its qip and join 

the larger mass to the west. 

The third dike is narrower than the other two. It 

ends bluntly on the northeast side of the open cut. 

A dike of similar width and position was recognized 

on the 300-foot level but was not traced confidently 

below it. On the 700-foot level a narrow dike that 

may be its continuation was found, but the gap between them was too great to warrant their connection 

on plate 14. If the two are actually the same, the 

dip must steepen to nearly vertical in the intervening 

distance. 

The contact of the quartz monzonite with the east 

side of the sedimentary block is a westward-dipping 

fault. These relations are similar to those at the 

U.S. mine, but here the dip of the fault is so steep that 

there is no danger of its terminating the ore zone 

downward. 

Another locality in which quartz monzonite is apparently exposed is in the south end of the 700-foot 

level in the hanging wall of the ore body, where a 

somewhat iron-stained rock of granitic appearance is 

found. A thin section of this rock showed that it was 

chiefly composed of a pale-green pleochroic amphibole 

and colorless humite, together with minor amounts of 

pleochroic apatite, titanite, iron oxides, and quartz. 

The rock is thus obviously a product of metamorphism, 

and it is not at all clear from the meager exposures 

whether or not it was originally a sedimentary or an 

igneous rock. Similar mineral assemblages have been 

found in other places in both sedimentary and igneous 

rocks. 

A dike of quartz monzonite porphyry is exposed 

both on the surface and on the 150- and 3DO-foot levels. 

Megascopically, the rockis dull greenish gray or light 

green and at the surface is dotted with brown limonite 

pseudomorphs after pyrite. Rectangular phenocrysts 

of dull feldspar as much as a quarter of an inch long 

are abundant but in most places are not conspicuous 

because of the prevailing light color of the rock. 

Smaller, irregular phenocrysts of quartz and a few 

glistening areas of white mica can also be recognized. 

Under the microscope the rock is found to be considerably altered. The feldspar phenocrysts have been 

entirely replaced by calcite and sericite; the mica, 

which was originally biotite, has gone over to sericite 

and chlorite and is locally crowded with sagenite 

(rutile) needles that have the characteristic stellate 
--

154 GOLD HILL MINING DISTRICT, UTAH 

arrangement; and the quartz phenocrysts show a slight 

veining by sericite. The groundmass is a finely crystalline aggregate of calcite, sericite, and quartz. 

In the vicinity of the mine the dike in places is near 

the contact between the sedimentary rocks and the 

intrusive, and the exposures are in general rather poor. 

For these reasons, and possibly also because of the 

local enlargement of orthoclase crystals in the quartz 

monzonite itself, some of the previous observers have 

considered, the dike to be a porphyritic marginal facies 

of the main intrusive. That it is a separate intrusion, 

however, is shown by the distinctive texture, linear 

trend, and independence of the sedimentary contact 

except near the mine. As the dike is followed to the 

south, it is found to be enclosed within the main intrusion, and three-quarters of a mile south of the open 

cut apophyses from the dike extend into the walls of 

quartz monzonite. 

Near the mine the dike strikes nearly north and dips 

45° or less to the west. Unlike the quartz monzonite, 

it is not susceptible to silicification and therefore 

appears to cut through the jasperoid without alteration 

(see pI. 14), although the jasperoid was undoubtedly 

formed at a later time. 

Another dike was found at the south end of the 

400-foot level, but it was not recognized elsewhere in 

the mine and is not shown on plate 14. It is a finegrained pale-gray rock in which are scattered rectangular crystals of calcite 1 millimeter long and a few of 

quartz. A thin section showed that the matrix consisted of fine-grained quartz and feldspar partly 

replaced by calcite and sericite. The calcite crystals 

probably represent former feldspar phenocrysts. The 

rock is too much altered to permit determination of 

its original composition. 

Ore bodies.-Three kinds of ore bodies are present 

in the mine-veins with silicate gangue, quartztetrahedrite veins, and large replacement deposits 

valuable chiefly for their arsenic content. 

Veins with silicate gangue: In the central of the 

three limestone wedges extending southward from the 

open cut there are several prospect holes on an altered 

limestone bed paralleling the eastern contact. The ore 

is similar to that at the Alvarado and Cane Springs 

mines, consisting chiefly of silicate minerals, especially 

wollastonite, that have replaced the limestone, together with small amounts of oxidized copper minerals 

and native gold. It is reported that the earliest work 

in the district was done on this deposit. So far as 

known it was last worked in 1892-95, when some ore 

was milled at the then active Cane Springs mill. No 

information is available as to the grade of ore mined, 

but the amount must have been comparatively small. 

Quartz-tetrahedrite veins: On the 150- and aOO-foot 

levels a quartz vein containing copper minerals is 

found in the limestone immediately west of the arsenic 

ore bodies and a few feet east of the quartz monzonite 

contact. Both exposures strike a little east of north 

and dip to the east. If the two are the same, as seems 

probable, the vein must cut across the quartz monzonite porphyry dike, as shown in plate 14. A similar 

quartz vein at the surface near the west wall of the 

open cut is probably the upward extension of the 

exposures underground. The vein ranges in thickness 

from a foot or less to about ao feet on the aOO-foot 

level, but the average thickness and the one most 

commonly found is about 5 feet. On the aOO-foot 

level the vein appears to terminate southward and its 

place to be taken by a zone of jasperoid in which copper 

minerals are disseminated. The contact between the 

two, however, is not exposed by the mine workings. 

Several small faults cross the vein on both levels and 

and offset it as much as 10 feet. The vein filling consists of coarsely crystalline white glassy quartz in 

which are numerous inclusions of altered wall rock. 

Disseminated through the quartz are specks and small 

blebs of pyrite and an arsenical tetrahedrite. The 

tetrahedrite in many places has been altered to a 

black sooty chalcocite, and films of chrysocolla, malachite, and azurite are found throughout the quartz. 

The quartz vein itself does not appear to have been 

mined at any place, but, to judge from the character 

of the two lower arsenic ore bodies, the higher copper 

content of the upper one (now represented by the open 

cut) must have been largely the result of oxidation 

and transportation of copper minerals originally 

present in this quartz-tetrahedrite vein. 

Arsenic replacement ore bodies: Three distinct 

arsenic-rich ore bodies have been developed in the 

mine. The first of these to be explored extended from 

the surface to the 150-foot level, being terminated 

downward by the dike of quartz monzonite porphyry. 

The middle deposit was found beneath the dike on the 

150-foot level and was followed downward to a few 

feet below the 400-foot level, where it appears to have 

been ended by the reversal in dip of the middle of the 

three wedges of quartz monzonite. The third ore body 

was found about 50 feet above the 600-foot level, 

below the quartz monzonite, and has been followed to 

the lowest workings. 

The outlines of the upper ore body are roughly 

those of the open cut although, as shown on plate 14, 

there is a triangular cropping of gossan extending 

northward beyond the pit. At the surface the pit has 

a length of 300 feet and a width of nearly 200 feet, and 

these dimensions are probably only slightly greater 

than the ore~bearing zone. . 

The middle ore body on the 300-foot level is nearly 

circular, with a diameter of nearly 100 feet. On the 

150-foot level the shape is similar but the dimensions 

are somewhat larger. On the 400-foot level, bowever, 

the circular form has changed to a tabular one, with a 

length of about 150 feet and a width of 10 to 30 feet. 

The lower ore body on the 600-, 700-, and 760-foot 

levels has a pear-shaped section with the bulbous end 

to the south. The maximum length of this lower ore 
MINES AND PROSPECTS 155 

body is somewhat over 200 feet, and the maximum 

width in the enlarged southern portion is nearly 100 

feet. On the 760-foot level there are two northerly 

prongs to the wider south end of the ore body, rather 

than a single one, as on the 600- and 700-foot levels. 

On this level, too, several faults displace the boundaries 

not more than 5 feet. A similar split in the ore body 

and minor faults are also indicated by the meager 

exposures on the gOO-foot level. The apparent localization of these two phenomena on the two lower levels 

is probably due to the fact that the ore bodies on the 

higher levels are thoroughly oxidized, and during the 

process of oxidation sufficient quantities of material 

have migrated through the original walls to mask the 

former position effectually. 

The location of the ore shoots is controlled by sev­

• eral factors. All the ore bodies when traced northward are found to be in beds of crystalline Ochre 

Mountain limestone. The easy replaceability of this 

rock makes it the most important single cause of ore 

localization. Obviously, anything that limits the limestone must also be considered as a factor. The quartz 

monzonite porphyry dike and the wedge of quartz 

monzonite that cut the limestone have clearly been 

unfavorable for ore deposition, as is shown by their 

lack of strong mineralization adjacent to the ore bodies. 

In a similar way the alteration of the limestone to 

lime-silicate rock has' been a negative factor in ore 

deposition, for this rock also must have been essentially 

immune to attack by the ore-forming solutions. On 

the 760-foot level, for example, lime-silicate rock occupies the space between the two northern prongs of the 

ore body. It also forms the walls of the ore in several 

places on higner levels. 

Two more direct factors in localizing the ore are , 	 suggested by the present exposures in the mine, but 

neither could be definitely proved because of the extensive surficial alteration. One is fissuring within and 

essentially parallel to a favorable limestone bed. This 

is illustrated on the 760-foot level by the occurrence of 

a pronounced sheeted zone that forms the footwall 

of the ore body and separates it from crystalline 

limestone. Unless a pre'liminary fracturing of the 

limestone were favorable or even necessary for ore· 

deposition, there would appear to be no reason for the 

sharp contact observed between the barren, unfractured limestone and the ore. The other factor is 

largely hypothetical. Plate 14 shows that the ore 

bodies individually and as a group pitch to the southeast, and that on several levels, particularly the lower 

ones, the south ends of the ore shoots are blunt and 

much wider than the north ends. These features suggest that there is some sort of a controlling or limiting 

fracture at the south ends of the ore bodies that 

strikes about at right angles to the ore and dips to the 

south. A fracture of this description appears to limit 

the ore southward on the 760-foot level but could not 

be recognized on the higher levels, where the ore is so 

thoroughly oxidized. Billingsley has reported that the 

upper ore body, now inaccessible, was controlled by a 

northeasterly fracture that dips to. the northwest.68 

This fracture obviously has not affected the two lower 

ore shoots, and this may mean that there is more than 

one cross fracture that controls the ore. 

The three kinds of ore that have been mined from 

the large ore bodies--copper, lead-silver, and arsenichave all been almost completely oxidized. Remnants 

of sulphides were found in several places on the 700­

foot level, but the 760-foot level was the only one on 

which the relations of the sulphides to one another 

could be adequately studied. The west prong of the 

ore shoot on this level is composed almost entirely 

of arsenopyrite, and the east prong is made up of a 

mixture of sulphides in which pyrite greatly predominates and arsenopyrite is extremely rare. Farther 

south, partial oxidation masks the relations between 

the two types of ore, but there seems to be a gradual 

in termixture. 

The arsenopyrite in the western prong has locally a 

radiating habit, but the great part of it is apparently 

massive and without crystal habit, a feature that 

polished sections show to be the result of a thorough 

brecciation on a small scale. Much of this ore contains little except the arsenopyrite. Near the hanging 

wall of the prong, however, euhedral crystals of arsenopyrite occur in a gangue of coarsely crystalline calcite; 

and near the south end of the ore body there is abundant fine-grained quartz, which has replaced both the 

calcite and arsenopyrite. The attack on the sulphide 

was most intense in the central portions of the crystals, 

and in many places the arsenopyrite remaining is simply a thin shell around a core of quartz. 

In the eastern prong arsenopyrite is either absent 

or is found only as widely scattered crystals. Pyrite 

is by far the most abundant sulphide in this portion 

of the ore body. It is veined by varying but usually 

small amounts of pyrrhotite, sphalerite, chalcopyrite, 

and galena. Pyrrhotite is especially abundant in the 

ore on the gOO-foot level. Calcite and quartz are 

sparse gangue minerals. At the south end of the ore 

body, where this assemblage of sulphides joins with 

the arsenopyrite ore, the arsenopyrite has been veined 

and replaced by them. 

The oxidized arsenic ore above the 760-foot level 

consists chiefly of the hydrated ferric arsenate, scorodite, and iron oxides. Its appearance varies greatly 

from place to place, depending on the amount of iron 

oxides present and the presence or absence of crystallinity in the scorodite. If iron oxides are absent 

from the ore, the color may be either white or green. 

The white material is shown by the microscope to be 

amorphous or cryptocrystalline matter in which collo­

.. BUlingsIey, Paul, Notes on Gold Hill and vicinity, Tooele County, Utah: 

Econ. Geology, vol. 13. p. 269, 1918. 
156 GOLD HILL MINING DISTRICT, UTAH

form textures are well developed. This material 

grades rather sharply into fine-grained crystalline green 

scorodite. Increase in the size of the scorodite crystals does not appear to affect the color greatly. A 

brown color is characteristic of most of the ore and is 

caused by the presence of small flakes of iron oxide. 

There appear to be all gradations of mixtures between 

pure scorodite and pure iron oxide (goethite?). .Although these two minerals are largely confined to the 

space once cocupied by sulphides, in many places the 

lime-silicate wall rock has been veined and impregnated 

by them. 

In addition to these two minerals, arseniosiderite 

and jarosite were recognized in several specimens, and 

pharmacosiderite is reported to be locally present. 

The green copper arsenate, conichalcite, was found in 

the stopes above the 400- and 600-foot levels, and W. 

F. Foshag has identified the similar minerals,olivenite 

and clinoclasite. The zinc arsenate adamite was found 

in hairlike crystals in the open cut. Halloysite and 

another clay mineral of similar appearance but anisotropic occur throughout the ore, and manganese, probably entirely in the form of wad, is in many places 

associated with them. 

The copper ore was found almost entirely in the 

upper ore body and has now been completely stoped. 

From the descriptions of Butler 6V and Billingsley 70 

the ore probably consisted of copper arsenates and 

carbonates in a gangue of iron oxides and scorodite. 

The copper content of the ore was close to 3 percent.71 

The writer considers it probable that the bulk of this 

copper was derived from the quartz-tetrahedrite vein 

that is now exposed on the west side of the open cut. 

The reasons for this view are, first, that no similar 

concentrations of copper were found in either of the 

two lower ore bodies, although they are otherwise 

similar mineralogically, and second, that the quartztetrahedrite vein was not recognized below the 300­

foot level. 

Lead-silver ore has been found in a number of places 

from the surface down to the 760-foot level, as small 

lenses within the arsenic ore. There appears to be a 

strong tendency for such lenses to be situated either at 

the south ends of :the ore shoots or near the hanging 

wall. A fine-grained powdery yellow-brown or greenishbrown material that appears to be made up of varying 

proportions of plumbojarosite and beudantite is the 

principal source of lead. Smaller quantities of mimetite, anglesite, and cerusite have also been found in the 

gangue of scorodite and iron oxides. 

A rather unusual assemblage of minerals was found 

at the south end of the 760-foot level and also at the 

bottom of the two south winzes from the 700-foot level. 

so Butler, B. S., The ore deposits of Utah: U.S. G601. Survey Prof. Paper 111, 

p.481,lm. 

70 Billingsley, Paul, Notes on Gold Hill and vicinity, Tooele Oounty, Utah: EOOD. 

Geology, vol. 13, p. 266, 1918. 

11 Butler, B. S., op. cit., p. 481. 

r 


At both of these places the bottom of the zone of surficial alteration is exhibited. In addition to minerals 

found both in the unaltered sulphide ore and in the 

completely oxidized ore, marcasite, chalcocite, supergene arsenopyrite in tiny crystals upon iron oxides, 

native sulphur, and abundant gypsum were recognized. 

Siderite appears to be rather widely developed at this 

horizon, not only at the two points cited but also 

north of the ore body on the 760-foot level. It closely 

resembles the smithsonite found in other western mining districts, but qualitative tests showed that it contained only a trace of zinc. Mr. Tiffany, who was in 

1925 superintendent of the mine, informed the writer 

that small quantities of native copper, orpiment, and 

realgar had also been found at this level. 

GOLD HILL MINE OF UNIT.ED STATES SMELTING, REFINING "" 

MINING CO. 

Locatwn and development.-The mine of the United 

States Smelting, Refining & Mining Co. is called by the 

company the Gold Hill mine but in the district is 

always spoken of as the U.S. mine to distinguish it 

from the Gold Hill mine of the Western Utah Copper 

Co. It is about 3,500 feet south of Gold Hill post 

office, east of the Lincoln Highway. The original 

claim, the Last Dollar, was developed by J. J. Gerster 

and in 1923 yielded a small shipment of copper ore.72 

In that year, however, a vertical shaft was sunk on 

the! claim and passed through 42 feet of scorodite ore 

that contained from 2 to 15 percent of arsenic. The 

Grasselli Chemical Co. obtained an option on the claim, 

but a continuation of the shaft disclosed' 30 feet of 

massive arsenopyrite, below which was found a mixture 

of arsenopyrite, galena, pyrite, and sphalerite in a 

quartz gangue.72 The United States Smelting, Refining 

& Mining Co. about this time took over the option 

from the Grasselli Chemical Co. and continued the 

development work on the Last Dollar and adjacent 

claims. In 1924 this company mined about 10,000 

tons of ore. Some of it averaged 38 percent of arsenic 

in carload lots, but the general average was 25.8 percent of arsenic, 30 percent of insoluble matter, 20 

percent of iron, 12 percent of sulphur, 0.5 percent of 

lime, 0.4 percent of zinc, 0.02 percent of copper, and 

0.86 percent of lead. Gold amounted to 0.03 ounce 

and silver 1.6 ounces to the ton. In addition several 

carloads were shipped that contained 10 to 16 ounces 

of silver to the ton and 6 to 13 percent of lead. These 

lots averaged 7 percent of arsenic.73 In 1925 arsenic 

ore of similar composition was shipped during January and February, but the drop in the price of arsenic 

prevented any further shipments. In that year, in 

addition, a carload of lead ore was shipped that contained 10.8 percent of lead; and in 1926 lessees shipped 

10 cars of similar ore reported to have averaged about 

12 percent of lead and 15 ounces of silver to the ton. 

7J Heikes, V. C., U.S. Geol. Survey Mineral Resources, 1923, pt. 1, p. 167, 1927. 

n Heikes, V. 0., U.S. Bur. Mines Mineral Resources, 1924, pt. 1, p. 41, 1926. 
MINES AND PROSPECTS 157 

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The principal workings at the mine (fig. 29) include feet of drifts and crosscuts that constitute the tunnel 

a crosscut tunnel to the ore body, which is the chief level. About 20 feet above this level is another series 

means of access. This adit connects with about 800 of workings known as the working level, but a larger 
158 GOLD HILL MINING DISTRICT, UTAH 

part of it is no longer accessible owing to stoping. In 

the vertical shaft that extends from this level to the 

surface the original discovery was made. An inclined 

shaft extends downward from the working level and 

ends at the 234-foot level, on which nearly 700 feet of 

work had been done in 1927. 

Geology.-Five formations are exposed in the vicinity 

of the mine. The oldest is the Ochre Mountain limestone, which crops out at the surface east of the portal 

of the adit and also to the north near benchmark 5416. 

It is a continuation of the outcrop in which the Cane 

Springs mine is located. Almost all the mine workings 

are in this limestone, although in most of them metamorphism and ore deposition have completely altered 

its original aspect. In the surface exposures as well as 

in the adit tunnel east of the quartz monzonite, the 

formation appears as a bleached and recrystallized 

coarse-grained limestone in which bedding planes are 

distinguished with difficulty. Silicate minerals are 

locally present in some beds. On the 234-foot level, 

east of the ore body, the limestone appears to have 

been almost completely replaced by pale-green garnet. 

In other places adjacent to the ore body, however, 

the limestone has been altered to a fine-grained palegray jasperoid. This rock at the surface weathers to 

a reddish-brown resistant rock that forms prominent 

outcrops. 

The Ochre Mountain limestone is overlain by the 

Manning Canyon formation, consisting of black shale 

and dark quartzite. The beds of quartzite are the 

only ones that are exposed at the surface, and in places 

where the Ochre Mountain limestone has been silicified 

it is difficult to locate the contact between them 

exactly. Small patches of the formation are exposed 

underground that show the black shale characteristic 

of the formation. In the exposures of the contact 

between the Manning Canyon and the Ochre Mountain limestone at the north end of the tunnel level and 

at the 234-foot level there is evidence of faulting, but 

from the essential concordance between the two formations on the surface, the faulting is thought to have 

been relatively slight. 

The Oquirrh formation is exposed south of the mine 

workings. It is made up of moderately thin bedded 

quartzites and limestones, some of the limestones 

silicified. It is not exposed underground. It is 

separated from the two preceding formations by a 

normal fault striking north of east. The beds that 

crop out just south of this fault must be near the base 

of the formation, for the fault is exposed at the south 

end of the tunnel level, and here the Manning Canyon 

formation is found in the hanging wall. 

The next younger formation is the quartz monzonite. 

It underlies the gulch west of the adit portal and is 

part of a bulbous outcrop that is connected with the 

stock by a narrower mass extending to the south. 

The main mass of the stock is exposed about 850 feet 

east of the adit portal on the eastern slope of the ridge 

and also about an equal distance to the north. A 

narrow dike of similar character crops out along the 

road leading to the old vertical shaft and is approximately at the Ochre Mountain and Manning Canyon 

contact. The intrusive is also exposed at several 

places in the mine workings. In the adit it is found 

for a distance of 150 feet from the portal. This is a 

part of the body exposed in the gulch below the mine. 

At the contact with the Ochre Mountain limestone 

there has been a slight copper mineralization on the 

south side of the adit. On the 234"-foot level quartz 

monzonite was struck about 60 feet south of the shaft 

crosscut and continued to the end of the drift. A 

raise near the end passed through the igneous rock in 

about 20 feet. The intrusive is also present in the 

northern workings. What appears to be the top of 

a dikelike mass was cut about 30 feet east of the 

massive sulphides, and at the end of this same crosscut another mass was found. The latter mass is 

separated from the sedimentary rocks by a fault with 

low southwesterly dip that is without doubt the same 

as one exposed at the surface east of the ridge above 

the mine workings. The quartz monzonite observed 

underground is all more or less altered. That on the 

tunnel level has been partly replaced by a later generation of orthoclase and quartz, and the dark minerals 

have been altered to actinolite, calcite, chlorite, and 

titanite. Moderate amounts of sericite are also found. 

On the bottom level dark silicates such as garnet and 

diopside have replaced the rock, and in the southern 

part of the level it is difficult to draw the contact with 

the metamorphosed limestone. The northern exposures are somewhat less altered but are badly crushed 

and contain veinlets of a pink ferruginous dolomite. 

The youngest rock formation exposed is a quartz 

porphyry dike 2 feet thick that is seen in the adit. It 

has been highly altered and is now a soft pale-gray 

fine-grained rock in which are phenocrysts of quartz 

as much as a quarter of an inch in diameter and of 

feldspar that reach a length of nearly an inch. The 

microscope shows that the matrix is composed of laths 

that were probably at one time plagioclase crystals 

but are now made up of a fine-grained clay mineral. 

The interstices between the laths· are composed of 

another clay mineral that has a lower index of refraction and a much lower birefringence. A little sericite 

and a few crystals of zircon and apatite are also present. 

This same dike appears to be exposed at the surface 

near the prospect hole 200 feet northeast of the adit 

portal. 

The Ochre Mountain limestone and the Manning 

Canyon formation, being essentially conformable, 

both strike west of north and dip 600 E. They are 

separated from the Oquirrh formation to the south by 

a normal fault that strikes north of east and dips south. 

This fault also is exposed in the most southerly work­

-
MINES AND PROSPECTS 159 

ings on the tunnel level, where the dip is seen to be 60°. 

It is of some economic importance in that it terminates 

on the south the beds of the Ochre Mountain limestone 

that contain the ore. 

A fault that is of much greater economic importance 

however, is the one cut near the end of the most easterly workings on the 234-foot level. This separates 

the sedimentary rocks from the main mass of quartz 

monzonite exposed east of the mine. On the bottom 

level the fault, along which there is nearly 4 feet of 

gouge, strikes N. 65° W. and dips 35° SW., but the 

trace of the fault on the surface indicates that its 

average strike must be closer to N. 25° W. For the 

reasons given on page 76 in the discussion of the 

structure of this part of the quadrangle, the fault 

probably has normal relations. If this is so, the fault 

must terminate the ore-bearing portion of the Ochre 

Mountain limestone at a rather shallow depth below 

the 234-foot level. From its average strike and a dip 

of 35°, it should be found about 200 feet below the 

bottom of the inclined shaft. Furthermore, the fact 

that quartz monzonite forms the footwall of the fault 

at the surface indicates that the faulted portion of 

the limestone has been eroded away. 

A similar fault is exposed on the 234-foot level about 

150 feet in the hanging wall of the fault just described 

which cuts off the massive sulphide ore. This fault 

strikes N.40o W. and dips 40° W. in the short drift 

and strikes N. 50° W. and dips 50° W. in the main 

crosscut. Projecting the Ochre Mountain and Manning 

Canyon contact that is exposed in the footwall of the 

fault, on the south end of the tunnel level, and the 

same contact exposed in the hanging wall, on the 234­

foot level, indicates that the dip slip approximates 

100 feet (fig. 30). 

The fact that the several exposures of quartz monzonite on the 234-foot level are not represented at the 

surface raises a question as to the probable abundance 

of the intrusive rock on still lower levels. Quartz 

monzonite forms the footwall of the fault exposed in 

the northeasterly workings on the 234-foot level, and 

the low dip of the fault must cause a rapid encroachment upon the ore-bearing limestone in depth. In 

addition, the southeastern continuation of the block 

of sedimentary rocks in which the mine is located 

shows conclusively that it is a part of a roof pendant 

in the quartz monzonite and that it is underlain to the 

southeast at a shallow depth by the intrusive. The 

Western Utah mine at Gold Hill, however, proves 

that such pendants may locally have a very considerable depth in proportion to their width. Proximity to 

the bottom of a pendant, as at the Alvarado mine and 

in the country to the north, seems to be indicated by 

an abundance of small plugs and dikes of monzonite. 

In one sense the two exposures of intrusive rocks on 

the 234-foot level, neglecting that in the footwall of the 

eastern fault, could be interpreted as suggesting such 

proximity. On the other hand, they might be correlated with the dike on the surface that approximately 

follows the contact between the Ochre Mountain limestone and the Manning Canyon formation. This dike 

cannot be traced southward to the region of the mine 

workings, and its top is presumably below the surface 

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in that direction. The more northerly of the two exposures underground might thus be interpreted as the 

top of the dike at that point, and the larger southerly 

exposure as a part of the dike that here extends more 

nearly to the surface but does not quite reach it. The 

only evidence in favor of this view is that the three 

are more or less in alinement, but considerably more 
160 GOLD HILL MINING DISTRICT, UTAH

extensive mine workings would be necessary to prove 

it. In figure 30 this interpretation has been accepted, 

and the dike is shown as being offset by the fault that 

terminates the sulphides, on the assumption that the 

fault is of the same age as that to the east which cuts 

the igneous rock. 

Several small faults can be recognized on the tunnel 

level by reason of the displacement of the quartz 

porphyry dike. At least four faults cut the dike in the 

25 feet between the two drifts that branch from the 

adit. The displacements are all small, and their 

algebraic sum is equal to zero, for the dike has the 

same position east of the fault zone as west of it 

(fig. 30). The largest throw appears to be along the 

so-called "lead fissure," and adjacent to it the dike .. changes its strike nearly 90°, becoming approximately 

parallel to the fault. Other fractures were recognized 

at different points underground, but the absence of any 

distinctive horizon in the beds cut by them prevented 

any estimate of their importance. To judge from 

surface exposures, however, their throws must be 

slight. 

Ore body.-The ore body of the mine is a replacement deposit in a belt of Ochre Mountain limestone 

which is at least 100 feet wide and whose eastern 

boundary appears to be the contact with the Manning 

Canyon formation. The limits of the ore are not well 

defined except where quartz monzonite or a later fault 

is adjacent. On the tunnel level arsenic or leadarsenic ore extends for more than 300 feet along the 

strike of this zone and for nearly 100 feet normal to 

the strike. The width appears to be at a maximum 

to the south and decreases to the width of the ,"lead 

fissure" at the north. On the 234-foot level the 

exposed mineralized area has considerably smaller 

dimensions. N early solid sulphides were cut for a 

distance of about 30 feet in the more northerly of the 

two east crosscuts and are terminated to the east by 

a fault. Disseminated sulphides, however, are found 

on this level over a strike length of about 175 feet 

and a width of nearly 100 feet. If the occurrence 

of sulphides cut in the raise at the south end of the 

level is considered, the strike length would be increased 

about 75 feet. On this level the apparent maximum 

width is much farther north than on the tunnel level. 

The walls of the ore bodies are of different character 

in several parts of the mine. The fault on the 234­

foot level is clearly later than the ore and is readily 

recognized. The quartz monzonite at the south end 

of the level is equally distinct. On the bottom level 

also a pale-greenish rock, which the microscope shows 

to be composed chiefly of garnet, is almost completely 

devoid of sulphides, except for thin veinlets and 

sparsely disseminated molybdenite. This rock may 

therefore be considered a well-defined wall rock, in 

that it has been distinctly unfavorable for the deposition of the sulphide ore. It is exposed on the east 

side of the drift for more than 50 feet north and south 

of the shaft and also makes up the stretch between 

the fault that terminates the nearly massive sulphides 

and the Manning Canyon formation. 

In most places, however, the walls are gradational 

contacts between nearly solid masses of sulphide and 

fine-grained jasperoidlike quartz with a very minor 

content of metallic minerals. Much of the ore zone 

on the 234-foot level is occupied by such siliceous rock 

with only a moderate content of ore minerals. On 

the tunnel level similar rock separates areas of highgrade arsenic ore and in such places might be considered as in the nature of "horses" of low-grade material 

between the more valuable bodies. Microscopic study 

of the siliceous material shows that locally it contains 

considerable amounts of a colorless chlorite and also 

of opal which in most of the occurrences seems certainly 

to be contemporaneous with the quartz. On the north 

end of the tunnel level, particularly adjacent to the 

"lead fissure", silicification has been much less prevalent, and in the hanging wall of the stope at the north 

end crystalline marble is found adjacent to the ore. 

On figure 29 the intensity of the stippling indicates 

approximately the relative amount of the ore minerals 

to the gangue. 

Ore.-Two classes of ore have been shipped from 

the mine-arsenic ore and lead-silver ore containing 

arsenic. On all the levels the arsenic ore is found to 

the south and the lead-bearing material to the north 

in the ore zone. 

The hypogene arsenic ore mineral is arsenopyrite. 

The southern part of the ore body in the tunnel level 

is made up almost entirely of this mineral. Locally it 

occurs as long, slightly radiating bladed crystals that 

are generally found near the hanging wall, though 

some are within the ore body. For the most part 

masses of the arsenopyrite are almost structureless 

as viewed in the mine. Polished specimens of this 

kind of ore, however, disclose that it has been thoroughly brecciated and later cemented by quartz. The 

chief gangue mineral in the arsenic portion of the ore 

body is fine-grained quartz. This not only cements the 

fractured arsenopyrite but also forms rather linear 

bands within the ore body, like the jasperoidlike material that acts as the walls in many places. On the 

bottom level the portion of the ore body that contains 

chiefly arsenic has a much higher content of quartz 

than is found on the tunnel level. Small quantities 

of pyrite and even less abundant sphalerite are found 

in the arsenic ore. They normally occur near the 

edges of the ore body. Polished sections show that 

the sphalerite contains microscopic inclusions of chalcopyrite, jamesonite, and pyrrhotite. 

The greater part of the arsenic ore on all three levels 

shows relatively little surficial alteration. Locally on 

the working and tunnel levels the sulphide is veined 

by thin seams of greenish massive scorodite, and in a 
MINES AND 

few places small vugs filled with crystalline scorodite 

were found. On the bottom level the arsenopyrite 

appears to be essentially fresh, but the approximate 

coincidence of the level with the water table has caused 

it to be locally coated by gypsum, nontronite(?), and 

a yellow-green fine-grained mineral that appears to be 

an undescribed hydrous iron arsenate. In the hanging-wall crosscut from the shaft on this level a reddishbrown ooze that contained considerable quantities of 

arsenic was being deposited. 

On the two upper levels about 25 feet north of the 

inclined shaft there is a rather sharp contact between 

) nearly fresh sulphides and ore that is almost completely 

oxidized to scorodite. This is associated with an abundant white chalky-appearing mixture of opal and 

quartz. The occurrence of oxidized ore at this point .. 	 is rather puzzling, because the vertical distance from 

the level to the surface here is somewhat greater than 

it is in the unoxidized area to the south. The explanation perhaps lies in the fact that there is much less 

of the relatively impervious jasperoid adjacent to the 

ore body here than there is to the south. 

The lead ore on the tunnel level is thoroughly 

oxidized, and as a result its primary relations to the 

arsenic ore are not definitely known. The wide lead 

stope just north of the shaft'immediately adjoins the 

scorodite portion of the arsenic ore, and in it, as well 

as in the small stopes on the working level above, both 

arsenic and lead minerals are found. A fine-grained 

pale-brown member of the jarosite group that is probably beudantite occurs in considerable quantities, in 

addition to varying quantities of cerusite, scorodite, 

and jarosite. In the large stope mentioned the ore 

appears to form a continuation of the wide body of 

rather poorly defined arsenic ore, and the arsenic con­ ., 	 tent is relatively high. North of the stope the ore is 

limited to relatively narrow veinlike zones in which the 

arsenic content is probably somewhat lower, as some 

of the specimens of the jarosite minerals occurring • to the north are found when treated to be nearly free 

of the arsenate radicle. 

On the 234-foot level the massive sulphides terminated by the northwesterly normal fault probably 

represent the downward extension of the lead ore on 

the tunnel level. In polished specimens of this ore 

arsenopyrite, pyrite, sphalerite, chalcopyrite, galena, 

jamesonite, aikinite, and stibnite are the metallic minerals recognized and are set in a quartz or calcite 

gangue. Pyrite and arsenopyrite are the most abundant of the sulphides. Both are thoroughly fractured, 

and the angular fragments are cemented by quartz and 

the other sulphides. The arsenopyrite is the more 

thoroughly fractured of the two, and in some places 

angular and cracked fragments may be seen that are 

surrounded by unfractured pyrite. Sphalerite is the 

next most abundant sulphide. It appears to be essentially contemporaneous with the quartz and shows no 

PROSPECTS 	 161 

sign of fracturing, It contains locally tiny dots and 

stringers of chalcopyrite, in addition to rounded remnants of the pyrite that it has replaced. Chalcopyrite 

was recognized only as small inclusions in the sphalerite. Jameaonite and galena are both somewhat later 

than the sphalerite, for they embay and vein it as well 

as the pyri~ and arsenopyrite. They appear to be 

mutually eX4jlusive, specimens that contain one being 

free from the other. Galena is readily recognized in 

polished sections by reason of its cleavage. It contains 

small inclusions of a darker-gray mineral that is aikinite, a copper-lead-bismuth sulphide. The relations 

between galena and jamesonite suggest that the formation of the one or the other was dependent on the local 

relative concentration of antimony with respect to lead 

at the time of ore formation. 

The only gangue mineral in the massive sulphide ore 

is quartz in very small quantities. In the lower-grade 

ore to the west the sulphides, chiefly pyrite and arsenopyrite, have replaced coarsely crystalline calcite which 

the microscope shows to have suffered considerable 

deformation. Locally a white soft claylike mineral 

that has some of the optical properties of kaolinite 

veins and coats the lower-grade sulphide ore. 

The relative proportions of the sulphides vary within 

the ore body. Pyrite or arsenopyrite or a mixture of 

the two generally predominates and in some places is 

present to the almost complete exclusion of the other 

sulphides. 	 Sphalerite appears to be somewhat more 

widely distributed and more abundant than the leadbearing sulphides. N ear the eastern boundary of the 

high-grade sulphide mass differing proportions of sulphides have caused a rude banding that strikes nearly 

north and dips about 500 W. 

There appear to be several factors that have controlled the ore deposition in this mine. The Ochre 

Mountain limestone is obviously the most important, 

in that it has provided an easily replaceable rock. The 

fault that terminates the limestone to the south and 

the quartz monzonite exposed on the bottom level 

both affect the continuity of the limestone. The rela­

. tively greater difficulty in the replacement of the formations thus brought into contact with the limestone may 

perhaps account for the large dimensions of the south 

end of the ore body. The alteration of the limestone 

to garnet and other silicate minerals is also unfavorable 

to ore deposition, as is clearly shown on the bottom 

level. 

These factors are negative ones in that they limit 

the ore body. A more positive factor in its localization 

is thought to be a series of fractures or minor faults that 

are essentially parallel to the strike and dip of the 

limestone. 	 The most evident of these is the so-called 

"lead fissure", which has faulted the quartz porphyry 

dike. Another parallel fracture that is closely related 

to the lead ore is exposed in the lead stope and at the 

north end of the working level. Its relation to the 
162 GOLD HILL MINING DISTRICT, UTAH 

dike was not observed. These fractures were not 

observed in the arsenic-rich portion of the ore body, 

but the linear nature of the siliceous horses in the 

arsenic ore and the apparent gradation between arsenic 

and lead ore may indicate that similar fractures were 

utilized by the arsenic-bearing ore solutions. 

The occurrence of the lead ores north of the arsenic 

ore is perhaps the result of the later introduction of 

the lead sulphides and the fact that the unreplaced 

rock to the north was more readily attacked than the 

nearly massive arsenopyrite. 

OREGON 

The Oregon group of 10 unpatented claims, owned 

by J. J. and Ada Gerster, of Gold Hill is west of 

benchmark 5416 on the Lincoln Highway, south of 

the town of Gold Hill. The workings consist of shallow 

pits and cuts, chiefly along or near a fault that separates the Ochre Mountain limestone from the Oquirrh 

formation. The fault strikes west of north and dips at 

a moderately low angle to the west. Along it the limestones have been crushed and thoroughly silicified 

and crop out as reddish-brown jasperoid. The footwall side of the fault line has been the site of two small 

intrusions of quartz monzonite in this vicinity. The 

work done has been in the nature of exploration for 

ores similar to those in the U.S. mine, to the east, or 

in the Cane Springs mine, to the northwest, both of 

which are in the same belt of Ochre Mountain limestone, rather than a development of any specific 

ore-bearing outcrops. 

HERAT 

The principal workings of the Herat mine are on the 

south side of the low hill about 1,000 feet northeast of 

Clifton. The mine was the scene of some of the earliest 

work in the district, and the inclined stack of an old 

smelter that treated the ores may still be seen extending up the side of the hill. In 1920 the owners of the 

mine were reported to be Messrs. Watson & Chandler, 

of Bingham, Utah. 

The early production from the mine is not known. 

In recent years several shipments, mostly of slag and 

speiss from the smelter dump, have been made by 

lessees. One of 156 tons was made in 1920 and had an 

average content of 0.025 ounce of gold and 11.1 

ounces of silver to the ton, 0.3 percent of copper, and 

7.4 percent of lead. Another shipment of 47 tons in 

1923 contained 0.021 ounce of gold and 16.0 ounces 

of silver to the ton, 0.15 percent of copper, and 11.4 

percent of lead. 

The mine workings are all in a mass of Ochre 

Mountain limestone that occurs as a blunt northward 

extending arm into quartz monzonite. The limestone 

near the mine has been rather thoroughly altered to 

lime-silicate rocks, and the detailed structure in the 

vicinity is not discernible. 

The ore bodies appear to have replaced the limestone, 

but the original outlines of the ore shoots and their 

structural relations have been almost completely 

destroyed. Ore apparently cropped out both north 

and south of the road that runs along the south side 

of the hill, to judge from the old stopes and workings 

that are found there. 

The ore that was seeninthe old workings and on the 

dumps was thoroughly oxidized. In only one specimen were any sulphide areas noted, and these were all 

composed of arsenopyrite. The bulk of the ore now 

visible consists of brown and greenish scorodite, 

with which are large amounts of dark-brown to black 

massive iron·. oxides. Small quantities of plumbojarosite or its arsenic-bearing analog and minor 

amounts of other oxidized lead minerals are present. 

Vein quartz in small quantities was also found on the 

dumps. It resembles closely the quartz of the tetra.;. 

hedrite-bearing veins, and the small copper content 

of the shipments may have been derived from this 

source. 

The scanty evidence that is now available indicates 

that this deposit is in many respects similar to the 

oxidized portions of the arsenic-rich ore bodies in the 

Western Utah and U.S. mines. There is some doubt 

as to any future importance of the mine, however, for 

the contact of the quartz monzonite with the sedimentary rocks in this region has in most places a very 

low dip, and as. the igneous rock is exposed at the 

surface only a short distance away, it probably cuts 

out the favorable limestones at no great depth. 

COPPEB.·LEAD·SlLVElI REPLACEMENT BODIES 

MONOCCO 

'rhe Monocco claim is about 1,000 feet west-northwest of Montezuma Peak and is reached by the northern branch of the central road leading eastward from 

Clifton Flat. The claim has been patented for many 

years and is now reported to be owned by the heirs 

of a Mr. Kimball. In recent years the claim has been 

worked by lessees. From 1917 to 1920 shipments 

amounted to 786 tons of copper and lead-silver ore, 

which had an average content of 0.002 ounce of gold 

and 3.52 ounces of silver to the ton, 10.17 percent of 

copper, and 0.88 percent of lead. In 1926 the claim 

was under lease to Richard Lyman, J. R. Driggs, and 

G. R. Steele. At the time of visit they had made a 

shipment of copper ore and one of lead-silver ore. 

The copper ore contained 0.01 ounce of gold and 3.6 

ounces of silver to the ton, 11.1 percent of copper, 15.9 

percent of iron, and 38.8 percent of insoluble matter. 

The lead.silver ore assayed 0.045 ounce of gold and 11.4 

ounces of silver to the ton, 8.8 percent of lead, 1.Q 

percent of copper, 2.0 percent of zinc, 3.5 percent of 

arsenic, 0.5 percent of antimony, 3.0 percent of sulphur, 3.8 percent of. lime, 2.5 percent of insolubl~ 

matter, and 25.6 percent of iron, Shallow cuts and 

tunnels are scattered over the surface of the claim, 

the only concentrated work being found in an incline 

200 feet long on the southern slope of the ridge south 

of the cabins. 

-

MINES AND PROSPECTS 163 

The workings are all in interbedded sandstone and 

limestone of the central facies of the Oquirrh formation. 

In the vicinity of the mine these beds strike N. 10°_ 

20° W. and dip gently to the east. No igneous rocks 

are exposed on the claim, but the western contact of 

the quartz monzonite stock crops out about 1,500 feet 

to the north and a slightly greater distance to the east. 

The ore is found both in fissures cutting the sedimentary rocks and as replacement deposits in rather 

pure limestone beds adjacent to the fissures. At least 

three fissures are exposed on the claim. They strike 

northeast and their dip ranges from 75° W. to nearly 

vertical. The thickness of ore in the fissures is generally less than 2 feet. Locally quartz-carbonate veins 

have been introduced along the older ore-bearing fissures. Eight ore-bearing limestone beds are cut by 

these fissures. Their average thickness is less than 3 

feet, and in many places only a part of the limestone 

has heen replaced by ore. Replacement has extended 

only a short distance away from the fissures, 15 feet 

being the maximum observed. Cherty limestone beds, 

sandstones, and limestone altered to silicates appear 

to have been unfavorable for ore deposition. At several places the ore beds are displaced a few feet by 

northwesterly faults that dip to the northeast. 

The copper ore is found either in or very close to the 

fissures. It is almost completely oxidized and consists 

chiefly of copper pitch in which remnants of chalcopyrite may locally be observed. Chrysocolla, azurite, 

and malachite are less abundant sources of copper. 

The lead ore is found chiefly in the limestone beds, 

although small concentrations of unoxidized galena are 

not uncommon in the fissures. Plumbojarosite appears to be the most wide-spread lead mineral, but 

where superficial alteration has been. less intense anglesite and cerusite are found, in places surrounding 

a core of galena. Fine-grained quartz and iron oxides 

are abundant gangue minerals, and in some places 

mammillary opal fills vugs in the ore. 

SILVER lONG 

The Silver King group, which has also been known 

as the Mineral Hill, is on the western and northern 

slopes of Montezuma Peak. It is said to enclose about 

200 acres of ground, which almost completely surround;; 

the Monocco claim. The owners of the claims are 

F. C. Little, of Moroni, Utah, and Ollie Young, of 

Clifton. Small shipments have been made from the 

group at different times. One shipment of 10 tons of 

ore containing 6 ounces of silver to the ton and 18 

percent of copper prior to 1912 is reported by Dick,74 

and one of 64 tons in 1917 contained 9.3 ounces of silver to the ton and 8.1 percent of copper. Shipments 

of less than a ton that were valuable chiefly for their 

silver content were made in 1920 and 1921. In 1922 

and 1923 shipments aggregating 132 tons had an aver­

.. Dick, J. C., unpublished mining report. 

age content of 0.035 ounce of gold and 18.1 ounces of 

silver to the ton, 2.77 percent of copper, and 5.19 percent of lead. 

The greater part of the development on the group 

has been done a short distance west of the Monocco 

camp. Here the interbedded sandstones and limestones of the Oquirrh formation strike N. 40° W. and 

dip 20° NE. These beds are cut by three ore-bearing 

fissures that strike northeast and dip 85° NW. Ore 

is also found adjacent to the fissure in two thin limestone beds which are unusually free from impurities 

and which are separated from each other by 10 feet 

of thin-bedded cherty limestone, which has been partly 

replaced by wollastonite. An inclined shaft has been 

driven down the intersection of the strongest fissure 

with the higher of the limestone beds for about 200 

feet, and from it have been extended several short 

drifts and stopes along the mineralized limestone. At 

the bottom of the shaft a fault striking N. 60° W. and 

dipping 30° SE. brings the ore bed into contact with 

cherty limestone similar to that in the footwall. If 

the two are the same, the throw along the fault cannot 

be much more than 5 feet. 

The ore is almost completely oxidized. In the fissures a deep-brown to almost black copper pitch is the 

chief copper mineral. Some of the black pitch is said 

to assay 62 percent of copper. Chrysocolla, malachite, and azurite vein the copper pitch in most places. 

Comparatively little lead ore is found in the fissures. 

It occurs chiefly in the adjacent limestone bed and consists of cerusite, anglesite, and plumbojarosite. Although the limestone is about 2 feet thick, in many 

places the ore is present in only a part of the bed, the 

remainder being unmineralized. 

Fine-grained quartz and iron oxides are the most 

abundant gangue minerals. In addition to being 

mixed with both copper and lead minerals, they also 

form a casing to the lead ore, extending beyond it in 

the replaced limestone bed. 

Other parts of the group show similar copper and 

lead-silver deposits, though none so far developed are 

as extensive. A moderate amount of shallow work 

has been done on these other deposits, particularly on 

the Searchlight claim, which is north of the Monocco. 

MOHAWK 

The Mohawk group is on the eastern slope of hill 

5852, about 1% Iniles west-northwest of the town of 

Gold Hill. In 1926 the claims were owned by Hicks 

& Hudson. Development work on these claims has 

beep directed toward the exploration of lead replacement ore bodies in limestones of the Oquirrh formation. The limestone has been bleached and recrystallized to a white marble but shows almost no development of silicate minerals. The ore shoots are for the 

most part rather small and contain considerable quantities of quartz and iron oxides in addition to the 
164 GOLD EILL MINING DISTRICT, UTAH 

oxidized lead minerals. There are numerous minor 

faults on the property. A small dike of quartz mon~ 

zonite crops out a short distance east of the workings. 

WALLA WALLA 

The W alIa Walla claim is on the eastern slope of 

hill 5702 about a mile and a quarter west of Gold Hill. 

It is oWned by Hicks & Hudson. The ore on the claim 

has replaced a limestone bed in the Oquirrh formation 

that strikes N. 20° W. and dips 30° W. A fissure 

striking N. 80° E. and dipping 65° N. appears to have 

afforded a channel for the mineralization. The lime~ 

stone bed is about 3 feet thick but has not been completely replaced by the ore minerals. The ore consists 

of quartz, iron oxides, a mineral resembling plumbojarosite, and scorodite. Some unoxidized remnants 

of galena were also observed. 

GARRISON MONSTER MINING CO. 

The Garrison Monster group of 27 patented claims 

is on the northeastern tip of Dutch Mountain. The 

property is owned by J. P. Gardner, of Salt Lake City, 

but during the period of examination it was being 

worked by lessees. The first locations are reported 

to have been made in 1882. The earliest recorded 

production, however, was in 1917. In that year and 

the succeeding two years 700 tons of ore was shipped 

that averaged 0.004 ounce of gold and 2.38 ounces of 

silver to the ton, 0.63 percent of copper, and 15.33 percent of lead. Production began again in 1924, and 

from the end of that year until July 1927 about 35 

carloads of ore were shipped. These shipments had 

a silver content that ranged from 1.16 to 6.2 ounces 

to the ton and a lead content from 6.70 to 40.40 percent. 

An old camp, consisting of a bunk house and several 

smaller buildings, is 1 %miles south-southwest of Garrison Monster siding on the Deep Creek Railroad and 

is reached by automobile along a road that branches 

from the Gold Hill-Wendover road a quarter of a mile 

north of the siding. The road branching from the 

main road south of the siding is passable by automobile 

~nly as far as the new camp near the tunnel portal at 

an altitude of 4,894 feet. 

Activity on this group of claims has been concentrated at three places-the Uncle Sam claim, three~ 

quarters of a mile southwest of the old camp in Royal 

Gulch; the New Year claim, at the old camp; and 

the Consolidated and adjacent claims, half a mile east 

of the old camp. The latter locality has provided 

almost the entire production credited to the company, 

and the tunnel at 4,894 feet, to the north, was driven 

with the idea of more fully developing the ore there 

exposed. 

Oonsolidaied claim.-The Consolidated claim is on 

the south side of the low hill (altitude 5,750+ feet) 

that has at times been known as Wilson Hill. The 

hill is separated from Dutch Mountain proper by a 

gulch eroded along a transverse fault. On the south 

side of the fault the Prospect Mountain quartzite is 

exposed. North of it are a series of nearly horizontal 

outcrops of formations that range in age from Middle 

Cambrian to Carboniferous. These are, for the most 

part, thrust plates related either to the Ochre Mountain thrust or to the transverse fault. (See structure 

sec. A-A', pI. 2.) 

The lowest outcrop in the vicinity of the claim consists of thin-bedded limestones and shales of Middle 

Cambrian age. In many places the limestones of 

this group have been altered to dolOInite. The portions thus changed have lost all of their original texture 

and weather to a deep-brown color. Next above is a 

plate of Upper Cambrian dolomite. This rock is normally deep bluish black and is thick-bedded, but in a 

few places individual beds have been bleached to a 

cream color. A 10-foot zone of thin-bedded limestone 

is interbedded with the dolomite near the mine workings. This plate is about 300 feet thick on the south 

side of Wilson Hill but is more than 500 feet thick on 

the north side. Both upper and lower contacts are 

faults, as is shown not only by the stratigraphy but 

also by the striking discordance between the bedding 

of the formations on both sides of the two faults and 

between the bedding planes and the contacts. The 

contact between the dolomite and tha underlying limestones is well exposed at several places on the east 

side of the hill at an altitude of about 5,300 feet and is 

made conspicuous by the contortions in the thinbedded limestones. The upper fault is not as striking, but close observation readily reveals its presence 

on the south side of the hill a short distance higher up 

the slope from the line of prospect holes on the ore. 

Overlying the dolomite is a plate of variable but 

small thickness, composed of interbedded brownweathering sandstone and blue limestone. Its lithology and fossil content are those of the upper portion 

of the Woodman formation. It in turn is overlain by 

100 feet or more of fossiliferous Madison limestone, 

the contact between the two being obviously a thrust 

fault. This fault is well exposed near the southwest 

shoulder of Wilson Hill at an altitude of about 5,650 

feet. The limestone is overlain conformably by about 

50 feet of reddish-brown sandstones and sandy shales 

that are characteristic of the basal portion of the Woodman formation. 

Igneous rocks are not abundant near the mine. The 

most prominent is an exposure of thoroughly altered 

porphyry in which the "porphyry incline", or main 

shaft, is driven. This is a white, irregularly ironstained rock in which a few quartz phenocrysts can 

be seen. Under the microscope a few laths of sericite 

after biotite are shown to be present, together with 

accessory apatite and zircon. The remainder of the 

rock is a fine-grained aggregate of quartz. The dike 

is exposed at intervals for more than 500 feet to the 

west. Another series of exposures of a porphyry is 
MINES AND PROSPECTS 165 

N 

\ 

40feet 

below collar 

\\~ 

\~ 

\\~ \ ~ \ v=5 

\ \~ 

\\'=5 

\ \«1­

\ \ 

)'­

FIGURE-gI.-Mine workings on Consolidated claim, Garrison Monstar mine. From sketch furnished by the lessees. 

present higher on Wilson Hill, along the thrust fault 

that separates the Madison limestone from the W oodman formation. 

In addition to the thrusts that separate the several 

plates, other faults occur in the vicinity of the mine. 

In the long tunnel, for example, two steep reverse 

.. rl 
166 GOLD HILL MINING DISTRICT, UTAH 

faults can be recognized at distances of 685 and 800 

feet from the portal, by reason of the repetition of 

exposures of the Middle Cambrian limestone. In 

other places minor faults are made apparent by offsets 

of particular beds or contacts. 

The ore appears to be localized in still another minor 

fault, for the wall rock is thoroughly brecciated, and 

its northeast strike and low northwest dip make large 

angles with the strike and dip of the adjacent sedimentary rocks. The fault fissure at the surface crops out 

within the plate of Upper Cambrian dolomite, about 

75 feet below its upper limit. Several prospect holes 

along it show that it has a strike length of about 

1,000 feet. The average strike as shown by these 

workings is east-northeast, but notable variations from 

this direction are shown by the mine workings (fig. 

31). The dip is also somewhat variable but averages 

close to 30°, as shown not only by direct measurements 

on the vein but also by the point of intersection of the 

vein in the long tunneL The fault is clearly later 

than the thrust between the Upper and Middle Cambrian, for the ore occurring in the tunnel has partly 

dolomitized Middle Cambrian limestones as its wall 

rock. 

In the main workings from the porphyry incline 

the ore is thoroughly oxidized. Gray sandy cerusite 

and yellow-brown powdery plumbojarosite are by far 

the most abundant lead-bearing minerals. They 

occur, in many places relatively free from impurities, 

in lenticular masses as much as 3 feet in width and 

10 to 20 feet along the strike. Such occurrences have 

a casing of banded reddish-brown iron oxides, in which 

are masses of a white clay mineral that appears to be 

largely halloysite. Smaller quantities of calamine, 

malachite, plumbojarosite, and other oxidized minerals are also included. The walls of the vein are 

composed of a thoroughly brecciated and bleached 

dolomite, in which there is locally a considerable 

amount of barite, and also isolated crystals of galena 

and limonite pseudomorphs after pyrite. In several 

places oxidation of the dolomite has converted the 

normally dense rock to a sandy aggregate of dolomite 

grains that closely resembles the sand carbonate (cerusite) found in the mine. The difference in weight of 

the two minerals, however, provides a ready means 

of distinguishing them. The rather scant exposures 

in these workings suggest that the shoots or concentrations of lead minerals may be correlated with synclinal warps in the vein. 

The continuation of the vein struck in the long 

tunnel nearly 1,000 feet from the portal shows very 

little oxidation. It consists of a zone of dolomitized 

limestone 5 feet or more in width that is impregnated 

with sulphides and white barite. Galena is by far the 

most abundant sulphide. Small quantities of pyrite 

may also be recognized in hand specimens, but the 

microscope is required to prove the presence of small 

quantities of sphalerite and tennantite. Another 

galena-bearing zone was struck about 150 feet nearer 

the portal. 

The exposures of the ore zones in the tunnel are 

much less veinlike than in the porphyry incline workings. This may be the result of the change in wall 

rock, for the thinner-bedded Middle Cambrian would 

probably not fracture as cleanly as the higher dolomites. The change might also be due to the fact that 

the exposed ore shoots on the higher levels pitch to 

the west and would at this altitude lie some distance 

westward along the strike of the ore zone. 

New Year claim.-On the N ew Year claim, a short 

distance west of the old camp, a long tunnel has been 

driven to the south with the expectation not only of 

tapping several small veins on the hillside but also of 

eventually reaching the vein on the Uncle Sam clainl, 

in Royal Gulch. The tunnel is now largely caved and 

could not be examined, but the writer was informed 

that nothing of consequence was found in it. 

Uncle Sam claim.-The workings on the Uncle Sam 

claim are about 1,500 feet southeast of the cabin in 

Royal Gulch, on the northeast side of the gulch. As 

shown on plate 2, the structure in this vicinity is 

extremely complex. A number of thin and discontinuous thrust plates are exposed beneath the Ochre 

Mountain thrust. 

The ore on the Uncle Sam claim was found in a vein 

essentially parallel to the bedding of the Madison limestone that forms one of these thrust plates. The ore 

mineral exposed at the surface is plumbojarosite, and 

the gangue is composed of barite and the limestone. 

A chute extending down to the gulch bottom seems to 

indicate that some shipments have been made from 

this claim, but the quantity and grade are not known. 

EVANS 

The Evans group of 21 claims, all of which are said 

to be patented, covers a large part of Royal Gulch 

other than that enclosed within the boundaries of the 

Garrison Monster property. Shallow pits, shafts, and 

tunnels are located at various places on the property, 

but so far as known there have been no shipments of 

ore. 

The workings are concentrated for the most part 

either in the "window" of pre-Carboniferous rocks 

exposed in the gulch beneath the Ochre Mountain 

thrust or in the Madison limestone immediately above 

the thrust. The geologic structure in this region is 

unusually complex. (See pp. 81-82). The ore bodies 

developed include both galena-barite replacement 

deposits in limestone, similar to those on the adjoining 

Garrison Monster property, and quartz-tetrahedrite 

veins like those on the Undine and Rea claims. The 

replacement bodies are for the most part in the 

Madison limestone, and the quartz-tetrahedrite veins 

in the pre-Carboniferous dolomites. 

-

MINES AND 

WILLOW SPRINGS DISTRICT 

HISTORY AND PRODUCTION 

The Willow Springs district was organized May 

21, 1891. Only a few claims in the district are within 

the Gold Hill quadrangle, and most of these, except 

for those of the Sunday group and the Dewey group, 

are unsurveyed. The production from the part of the 

district here considered appears to have been limited 

to a few small shipments of high-grade ore. 

PROSPECTS 

DEWEY 

The Dewey group of five patented claims is on the 

north side of Sevy Canyon about half a mile westsouthwest of South Peak, which is on the ridge line of 

the Deep Creek Mountains. Swan Moline, of Gold 

Hill, reports that a shipment of 800 to 900 pounds of 

. ore was made from the property between 1890 and 

1900 and yielded about $1,800, the valuable metal 

being silver. 

The country rock in this vicinity is the upper portion 

of the Laketown dolomite, of Silurian age. A strike 

fault of low westward dip cuts the dolomite and has 

resulted in considerable brecciation. The fault has 

caused a repetition of beds in the dolomite and is 

therefore of the reverse variety. The throw was not 

determined but probably amounts to a few hundred 

feet. 

The dolomite breccia along the fault has been 

cemented and partly replaced by fine-grained quartz 

across a width that is locally as great as 20 feet. In 

places the quartz is vuggy, and the vugs are lined with 

terminated quartz crystals. In the lower portion of 

the zone there is abundant coarsely crystalline white 

dolomite in the breccia. Several small prospect pits 

and stopes have been opened in this quartz-rich zone, 

and this material apparently constituted the ore. The 

only signs of mineralization other than the quartz are 

a few copper stains and small quantities of iron oxides. 

It is probable, in view of the copper stains and the 

high silver content of the ore shipped, that the valuable 

mineral was tetrahedrite and that the deposit is related 

to the quartz-tetrahedrite veins in the Clifton district. 

SUNDAY 

The Sunday group of 16 claims is in Bagley Gulch, 

on the south side of North Pass Canyon. The claims, 

some of which were being surveyed for patent in 

1926, are owned by the Bullion-Bagley Mining Co. of 

Salt Lake City. A camp had been established at the 

point marked" 7058" on the topographic map, within 

a short distance of which the prospecting activities of 

the company were concentrated. 

The Abercrombie formation underlies the surface 

in the vicinity of the claims, and almost all of the 

prospecting has been done in the dolomitized massive 

limestones of that formation. The group of claims is 

PROSPECTS 167 

about halfway between two northwestward-striking 

transverse faults, and the minor faults and fractures 

in the region, including those followed by the veins, 

are apparently related to them, as they have parallel 

strikes. 

Prospecting has been done at several places on the 

group of claims. What appears to be the most 

promising deposit is a quartz vein exposed a short 

distance north of the camp. The vein is from 1 to 3~ 

feet wide, strikes N. 65° W. and has a dip that ranges 

from vertical to about 80° S. The vein mling consists 

of coarsely crystalline white quartz that contains 

numerous vugs lined with terminated quartz crystals. 

In this are local concentrations of galena and tetrahedrite 

with their oxidation products. Some of this sulphidebearing ore is reported to contain as much as 1,700 

ounces of silver to the ton, but so far as known no 

shipments have been made. 

South of the camp a shallow shaft has been sunk to 

explore several "watercourses" in the limestone that 

are mled with barren iron oxides. No valuable minerals had been found in this material at the time of 

examination. 

LEAD CARBONATE 

The Lead Carbonate claim is in the south fork of 

Dry Canyon, at an altitude of about 7,200 feet. The 

present ownership of the claim and whether or not it 

is patented are unknown. The ruins of small buildings 

below the workings indicate the site of the former 

camp. The claim was worked in 1917 by W. J. 

McLaughlin, of Salt Lake City. 

The workings are all in mottled limestones that are 

dolomitized here and there in the vicinity of the claim. 

The beds at this point strike a few degrees east of north 

and dip 35°-40° W. A large transverse fault, striking 

east, is exposed about a quarter of a mile north of the 

ore shoot. 

The ore has replaced one of the limestone beds and 

is localized in a shoot that has a strike length of about 

10 feet and a width of 2 to 3 feet. It appears to pitch 

to the southwest. An inclined shaft has been driven 

on the shoot, and a tunnel, whose portal is 40 feet 

below the outcrop, extends toward its projected 

position in depth. No transverse mineralizing fracture, such as was observed at other replacement bodies 

of this type, was recognized at the surface. 

The ore appears to have been completely oxidized 

at the surface, but some specimens of relatively 

unaltered ore, presumably from the lower part of the 

ore shoot, were found on the dump. They showed 

veinlets and blebs of galena and tetrahedrite embedded 

in limestone or dolomitized limestone that contained 

a considerable amount of quartz, much of which was 

in the form of terminated crystals as much as a quarter 

of an inch in length. At the surface much of the carbonate has been leached out, leaving a skeleton of 
168 GOLD HILL MINING DISTRICT, UTAH

quartz, with which are associated various oxidized 

lead, copper, and iron minerals. 

One shipment of 8 tons of ore was made from the 

claim in 1917. This contained 18 ounces of silver to 

the ton and 37 percent of lead. It is probable that 

some other small shipments have also been made. 

SILVER 

The unpatented Silver claim, which in 1926 was the 

property of Alvin Trippe, is on the south side of Dry 

Canyon a short distance east of summit 8182, at an 

altitude of about 8,000 feet. . 

The ore is found in fissures cutting dolomitized 

limestone in the lower part of the Abercrombie formation. The fissures strike about N. 70° W. and dip 

very steeply to the northeast. They are from 2 to 6 

inches in width and are filled with quartz, fragments 

of wall rock, and oxidized copper, lead, and iron 

minerals. The wall rock shows minor amounts of 

silicification away from the fissures. Only a relatively 

small amount of shallow work has been done on the 

claim, and apparently no ore has been shipped. 

OTHER PROSPECTS 

There are several other prospects in the part of the 

Willow Springs district that is included within the 

quadrangle, particularly near the mouth of Dry 

Canyon. These do not differ in any important respect 

from the prospects already described, and as the names 

of the claims could not be ascertained they are not 

described here. The name of the claim upon which is 

located the shaft shown on the map near summit 

6954, on the north side of North Pass Canyon, is alsd 

unknown. The shaft is an incline sunk on a few 

parallel joints that strike N. 85° E. and dip 75° S. 

No valuable minerals were observed in the shaft or 

on the dump. 

I 

L 

::;)::::::s: = 
INDEX 


A 

Page Abercrombie formation, age and correlation oL___________________ •••• _. ___•• '10 


distribution of___ •••••• ___ •__ ••______••_••_•• ________ •_____________•____• 8 


fossils of_••_._. ______ ••••___ ••___ •______ ••• _. _•••____•••••••••_••..•_.... 10 


lithology oL•..•' •.•••_••••'•••••• _"'..•••••..._...............•••••••••• S-9 


section oL••••.--_•• __ -••.•.••••••••••: ._•.•..•••.•.•.•••••_""""" _.. 9 


thickness of. ••,•.... _•.••__•.•••___ "'___ .•• __ •..__ ._._._". _____ • ____ OM 9 


Abstract of report:••••_•••••.... __ ..___ •__•• ____________ •.._. _____ . _. __ •__ vn-vrn 


Accesslbillty of the area__ ._•.•.•_._. __ ._•••_•• ______••__ .••________ •__ •__••• 1 


Acknoyv\edgments for ald._._._. _______ •••_••• _••• __ ••••••••••• _•• _______ .... 4 


Actinolite, occurrence of•••_-.-________ ._._••_.••___ ._._. _. ______•• ____ ______ 114 


Adamite, occurrence of___•___ .--__ -------_______•__________ •____ ._ ••_._.____ U6 


,(I.lkinite, occurrence of_•••_. ____••••••"._•••• __ •___ ••• _. __ •••_•••• _,_""_,, 112 


Ajax limestone, correlation oL••• _••••_•••••. __ ..____ ._._._••••••••••._.••_. 15 


Albert claim, features of.••••••••••••••• _••.. ___ .'" _.. ______ ... __ ••••• "" 127-128 


Albite, occurrence 113 


Alkali baslllt, partlalaualysis ot.•...••..••.• _••....•.. ____.•".............. 52 


petrography of••. ___ ••_.....••••_••••••••• _'" __._..••••.._._._ ••• ___ ••• 52 


Alteration of ores, relation of physlcoJ and chemical character to superllcilll•• 105-107 


relation of water table to superllcilll________ •••• __ •••_•••• __ .•_........... i04 


Alvarado mine, features of__•______ •__ ...._._••.••••__ ••••••__•..• __ •___• __ l2s-UIl 


Ampbibole, apatite and molybdenite In__ ._......___•••••••_••••_•._____ ._.~ pI. 9 


Andalusite, occurrence of.._________ ••• __ . ___ •___._.._._._ •••••••••:••• _~.. ~~ 114 


Andesite, biotite and hornblende, petrography oL._••• __ ._._____• __ ._._.... 50 


Anglesite, occurrence of____•_••__ .•_•••.__________ .••_. _______ ••• ___ •••_._... 117 


Apatite, occurrence of. _•• __ •• ___ ••• _••.• ___ ••• ___________ •_______•_______ MO. 116


Aplite dikes, features ot._._ •••.•_. ___ •___ .........___ ._. ___._.••..___ ••••••• 48 


Arseniosiderlte, occurrence oL__ ._......__ •.••• _•••. _._._. __ ._•.______ ._ .••__ 116 


Arsenopyrite, occurrence of••_. __ •________ .•• __ ••_••••••. ___••_._••_______ ••• 111 


Axinite, occurrence ot. ____ •• __ •___ ._ . ___ •• __ ._••••••••.• __. __ ._. __•___ . ___ . _ 114 


Azurite, occurrence ot. _________ •_--. -- ___ -- _------- _____ --c-- _._••• _____ .. __ 113 


B 

Bamberger mine, features of__________• ________ ._. ________ •••• __ •__ •••_..____ 125 


Bar Creek, anticline west 01. _____ •• ___ • _______ • _______ . _____.._________ ._ ••• 87-88 


concealed thrust fault west oL•••_•••• _.•••••••_•• _._ •.•••••••••••_••••_ 88 


faulting west of.••• _••••.•......_...•..•••_•••••••••• __ ••••.••••••••• ___ • 88 


minor faulting east oL__ . __•_________._••_____ ._. ___ ._....___ .._._ •••••• 86-f!7 


minor folds west oL._•••••••••••.••_.•••••••••••••••••••_•••••.•.•••.•.. 87-88 


Bar Creek fault, rela tions ot.••_...._••.•••.•.••••..••..••.••_•....••.......• 56,87 


Barite, occurrence ot...._..._.•..•_......__ ._................................ 117 


Beudantite, occurrence or.•••. _••• __•••••••••__ •..__••••••_••_...._••_•••._._ 117 


Bighorn dolomite, correlation of••••••••••-­ ..-.-...•.....-••--.".-••• -•••-.. 17 


Biotite, occurrence of_........_••..•_•••••••••••••_. ___ ...••_._ •••••••••_•••_ 115 


Bird claim, features of._•......._.•.••• _•••••_••••... _.•........_...••• __ •••_ 149 


Bismuthinite, occurrence oL. __ ...•••••.•• _••••• _•••. _. ____ •.•._•••_._._.... 111 


Bismuth, occurrence oL••• __ ._ •.•• _._...._•..__ ._ ••• __ ••• _•• ___ .._••••••••_. 110 


Bismutite, occurrence of_.• _•...•....... __ .._.••••_.• _•••. __ .•• _.•. _....__._. 113 


Blood Canyon, normal faulting in._._...._.••_._ •• _....._._ •.•._._.• _....... 70 


Blood Canyon fault, direction and amount of movement Illong••_. _•• ______ .•• 69 


relations 01. .••...... _.••_._ •••••• __ .. __ ... _•. _. _. _..• __ ._._.._•••••• _. _. ~\I, 67 


Blood Mountain, minor structurlll features on. __ ...•._••••••__ •••••• _•.•_•.. 68-69 


Bluebird dolomite, correlation of..•_•• ___ •• __.._••...._.•...._..•••••••••• __ 11 


Bonanza claims, features ot.•••.•••• _••••••.•_..._......_•• __•••• __ ••_....... 144 


Bonnemort claim, features 01.......•.•••••• _•••••••• _••• _._ •.••••••••••_•• 135-136 


Bonneville beach and spit, view or. •••. _.•.•_._ ••_,•.. _.•. _._.._.........••• pl. 4 


Bornite, occurrence of_. _••••_••• _•••..•••••••• __ .•••• _••_•._._ ••_••• _•.•_... III 


Boston claim, features of.............. ___.••_..._•••• _.•_. __ ••••••_......... 143 


Boulangerite, occurrence of.••••••.••••._••.•.•••.__ •.•••••••_............... 112 


Bowman limestone, correlation of••••••••••_..•_•••_•• _••••••..• _._•.•.... _. 10 


Brazer limestone, correlation of•••• __ ...._••_•••. _•..•.••.••••• ____••••••••.. 28,30 


Burling, L. D., fossils collected by••_•• __ ._...•___ ..•._.....•._••.••• _._..... 27 


Busby quartzite, age and correlation of_ •••••••••••••••._•••• __ ._•••••• __ .~.. 8 


distribution of•••••••_•••.......•_••••••• __ •• __ ..•.••.._........••• _••••• 7-8 


lithology of•••••••• ___ ..•.•••...__ ._••••.•••••••...._.• _•.•..••_. __ .• _'" 8 


thickness of. •••• _.••••••_._ ••.•••• __ ._•• _••• _.'••..•••._._. _. _•••_.. .... 8 


C 

Cabin shale, age and correlation of_._._.•••••_•••••.••••. __ .................. 


distribution or...•_•••••••••• _••••• __ •••_••••••• _•••_•••••••••• _....._... 6 


lithology ot.••••..•......•..._..................._....................... 6-7 


thickness of••_____••.••_••••••••_•• •• __•____ •••••..• __••_._.__ •••_..... 7 


8Ill11-3G--12 

r 

Page Calamine, occurrence of__ •••••.•••••.•_.•..._•.•_••••• __.................... 115 

ClllaverllS claims, features of••_............_•••_••••••••••__•____••.•••••...• 124 

CoJaverlte?, occurrence of. •__ ••••_•••• __......_•.• _•..... _........___ ....... III 

Clllcite, occurrence ot.._.__ ....•_•••_•••• _••••••••. _.••.•••.•.__ ••_..._._•• 112--113 


Cambrian beds, U:nconformity at top of upper _•.. _._•••_••_••••••••_•• _._. __ 14--15 


Cambrian system, formations of••••• __ ••••_. _____ •._........•._•••..•••••••_ 4--15 


Cane Springs mine, features oL.•......•••• _••••••__.•••••.•.•. __ •••••.• __ 131-134 


Carbonate·sulphate. veins, alteration or. ..•••_...__................_••••• _... 105 


features ot.••_.__•••••••• _•.• _•.•.•_......._••_••.••.• _............._.. 101-lO2 


,mines. and prospects in........................ __••••••.••_.............. 151 


outlOOk for mining....._..........__....._..•.• __ ............._••••_..._. 110 


Carboniferous beds, unconformity at base oL.. ___ ._ ••••, •••_••• _••..•...... 21-22 


Carboniferous system, formations of_•••••...... _.....••••_••••••••_...._.•_. 23·42 


formations of, correlations of.............._._ ••• _................. __ •••• 41-42 


Cash Boy claims, features oL__ •.•..••••••• _•.• _••_...__._.•.. _.._••_..... 148-149 


Centennial claim, features ilL •.•••.••••• __ •••••• _•• _•••••.._...•••....•••_ 122--123 


Cerusite, occurrence of.••••.__..._•• _._............,_...__ " ________ •• _••__ • 113 


Chalcanthite, occurrenoo of........_••.•...•••••--............." •._, _.. ..... 117 


Chalcedony, occurrence of•._...._. _•••••.•.•_._. _._ ............._•....• __ • _. 112 


ChalCOCite, occurrence of.. __•••.••• _._.•___• __ ••••••.•••_•. _..•••••••_._.... III 


Chalcopyrite, occurrence ot._._•••••.-­......_..._.•••••___ •_. ___ ....._.....• 111 


Ghisholm shllle, correlation or. •••••••• ____ . __ ._•.•....••• _•• _...•___ ..•••___ 10 


Chlorite group, occurrence 01. ••••••• _•••___._ •._...__ ._ •.• ___ ....._. ____ ..._ 115 


Chloritization, Illteratlon of qUllrtz monzonite by•••• _................._..... 9~ 

Chokecherry dolomite, age and correlation of._..._. __ .......••__ ......_._... 15-16 


distribution oL._..•.....•.• _••• _. """ _•.•.•_. _____ ..........._•.• __ . _ 15 


fossils of•.• _....................-.-.•.•• _•• __ ••_••••••_••_•••_........._. 15 


lithology ot.•••••. __••••..•-..-..•----.......................__ •• _. ___ •_. 15 


thickness ot. •.••••• ___ .,........-••.- __ ••••••• __ •• _••• __ .•.._........... 15 


Christiansen and Sheridan Qulches, minor structural features between•._••• __ 69 


Christmas Mining Co., cllllms of........... ______......._•••••••••. _........ 151 


Chrysocolla, occurrence ot. __•••••••_._••____ ...•..••••••.•_. __ •• _••••• _. ___• 116 


Claron limestone, correlation oL....._._••..........••... _..•_.............. 43 


Clay and gravel, older, occurrence and cbllfllCter oL..._._._._.•_•••••_•••_._ M 


Clay minerllls, occurrence oL._•....•__ •••• __••••• _..........._•.__•••••.• 115-116 


Clifton district, history of minlng ill_.•_........... __ ••••••••.•• ___••••_..... 118 


mines and prospects In•..••_......................__ ...•.••••••••••••• 119-166 


production ot.._•.••••••_................__ ••••••_..........._•. _._. ... US-U9 


Clifton Flat, major anticline south oL.•.•_•.•.•_••••••_•••_._.............. 70 


minor faults west and southwest or.. ___ .•_. __ ._••••••••••••••••••••.• _.. 70 


view of, from the southwest......._••• _•.••• __•. __•• __ •••••••••.. __ .••.. pI. 4 


Clinoclasite, g::e~I::S~~~t;;~·~f~ occurrence of. == ~== ======:================ =:=:==::=======:=:=:: ...............__ ••_••..••_"""'.,_. _•••••••• ___ i~; 116 


Clinozoislte, occurrence ot.•• _•.•••••••_._...._____ .._._....'_'" ,_•••••_•••_ 114 


Cole Canyon dolomite, correlation ot...•••.• ___ .••__ •••.•._•.._. ____ ..__•..• 12 


Conichlllc!te, occurrence of. ••••• __ .............._••••_•••••..•_...•.••.•_. _. 117 


Consolidated claim, features of__ ._._•••.•.•••••••••••••• _. __•..... ___ ••••• 164--1tl6 


Copper Bloom claims, features of_._.•. _•.• _._ ••••.•.••••._••. _.• __._._.•• _.. 127 


Copper Hill claims, features of.___ •••....•.. _..._.....•_••• ___ ........._••. _. 128 


Copper, occurrence of..._.•••••••,. _.._........._..••••••••••••. __ ••_....••• 111 


Copperopolis claims, features oC •••• _••••_••.••••..•.••••.• _••.• __ ._ •••. _... 125 


Copper pitch, occurrence oL...._•••• __ •••••.--..._..........._._. __ •••_•••__ 112 


Copper Queen Midland Mining Co" claims of. ___ .•••_.•.•.• _••_•.• __•__••• 148 


Covellite, occurrence of.•.••• _........_........._••• _••••••••.••••••••_•• ____ 111 


Cuprotungstite, occurrence 01. .. _.••__ ••..••••.••••• __••....•.•••.•••••••••• 118 


Cyclone mine, features of.......... __ .•_.••••••••••_.........___ •••...•._•• 144-146 


polished section showing arsenopyrite fragments cemented by other sulphides lind qUllrtz from.•••.__ .•••_._ ..........__..__ .•••••..••. pI. 10 


D 

Dagmar limestone, correlation of••••••••••••_•.. __ ••••••••••_••••• __ •••••••• 10 


Danburite, occurrence 01. .•_•••••••••••••• _••••••••••.•• ___ •.• __ •••••••_.... 114 


Deep Creek Mountllln block, mutual relations of structurlll features of•••• _. 69 
 structure of••__••••• ___________ •__ . _. _••••• ___ ..._••••••••..• _•.•. __..... 66-69 


Deep Creek Mountlllns, fault Illong east base of..._••••___•••••• _._ ••• _..... 56 


fault Illong east base of, relations oL...•.....•••••__ •••_..•.•. __ .•••_... 68 


structure of..•.•••••: _•••••••.•••••__._•••_••.. __ .•••.• _......: _.___ ..•.• 55 


Deform.ation of the beds, progressive variation in character of•••••••••••. _.•. 60-61 


Descloizite, occurrence of..•__•____...__••••....._..•...•.•• oo ......_ •• __ ••• _ 116 


Deseret limestone, correlation of••• __ .........____ •. _........................ 28 


Devonian system, formations of•••••••••••••••••••••••••.••••._•••••__ ...... 1S-21 


Dewey claims, features oL....................___ •.•__. ___ .•••.•••_......... 167 


169 


m 
170 INDEX 

Page 

Dikes, porphyry, appearance of. _____________ ••..._••....___ ...•••_......... 46 


porphyry, distribution and size of. _______ . _____ • ___• ___ ._ •• _•• ___ . ____ •• 46 

microscopic features oL._. __ . ____ . ___._... ___ ...._.•._••.._.•_.•...• 46-47 

relations of, to one another ......_.. ____• ___ ._•. __ •••••_______•• __•.. 47-48 

relations of, to other rocks. ___ . __ •. ___ . __._.... __ . ___ .•__ ._•••• _.._.. 47 

Diopside, occurrence ot. •• __ ..• __ ..... ______ ._._••• _. ____ . ____ . __ .•.•.•_..___ 113 

Diopside-orthocIase alt<lration, features oL____••.._____ .. ____ ._•..•_.__ •.... 94-95 

D~tor claim, features of ____ .....___... __ ...__ •• __ . __ ••• ___________ ._.•_..._. 122 

Dolomite, occurrence of. .....____•. ____ .•__ ••._._. __ ... _.. __ . ___ .._..____ ..• 113 

Dolomitic formations, origin of the pre·Carboniferous. __ •••.•__ ••• _. __._•. __ • 22-23 

Dolomitization, features oC __ ..._•. __ .•. _•. ______ •. _._._... _. ______ ..._..... 94 

Dry Canyon and Sevy Canyon faults, minor faults between •••.. _._ •••.J.... fIi 

Dry Canyon fault, relations oL.___ •••. __ ._._....__ ........_..._._.._.•_•.. _ 58,66 


minor faults south 66 

Dutch Mountain block, structural features of, mutual rele.tlons 85 

structure of.. ______ .,••.• _._ •.....•••_..._•.....•.._•••• __•••••.••••••.._ 78-85 

Dutch Mountain, fault along west side of. __ •••._••••_...................._.. 85 


faults on___._. __ ....•••., __ ••__ .••_...._•...•••.• _••._._....._.•_._...... 56 

-relations of recumbent anticline to structural features on._. __ •••..••••..• 86 

view of, from the southeast_•. _..•_.•••.._.••_..•_•.. "~ ••.•..••_•.. _•.• _. pI. 4 

Dutch Mountain thrust, features ot. __ . __ ..__ ._...._•. _•...• _..•.....•_._... 54 

relations ot.. _______•.•_____ • _ •.. _._. ___•___ .. ___ ... ____ . ___ . _____....._. 84 

E 

Ely Springs formation, correlation ot. __ . __ . ____ ._•.•_._. __ .•_.., ....___ •._.. 17 

Enterprise claim, features oL____ .•.... __ ..._._...••••__ •• _. __ ••••• __ ••_•• 122-123 

Eocene (1), unconformity at base ot._ ...•• ___.••.•_..•__•• _..._._._.••_..... 42 

Erosion surface, dissected postmature_._ ••__ .•...._. _____ .•____ •• ___ ••• ___._. pI. 6 

Epidote, occurrence of ___ .•.•__ ..._..____ . _.•___• _. __ . ___ . _..•. _. __ .•_.___ ••• 114 

Evans claims, features of. .••..•.•_••. __ .•••• _..._....•.•.._. _•.._. __ .. ___ ••• 166 

F 

Fairchild, J. G., chemical analyses by..__ . __ .• _.•___ ......___ .•_. __ .. ___ • 50,51,52 

Faulting, late normal, characteristics oL.____ ... __ •..._•••.•.• _•.. ___ ••. ___ • 63 

late normal, relation 01, to present topOgraphy ____ ._.. ____ . __ . _____ ._ •• __ 61-{l3 

Fanlts in Gold Hill quadrangle, map showing_•.._. _____ .••.. pI. 3 (in pocket) 

Ferrisymplesite?, occurrence 01.•...••_.•••••_.. _____ . __ ._ •••••_._ ._•••••_... 116 

Field work ..____•._••.•. ___ .•___ ••._•••.....• _...• _.•.._•.. _..__ ._. _. __ .... 3-4 

Fl&h Haven dolomite, age and correlation ot.__ .._._ ...___ •_____. ____ ...___ .. 16-17 

distribution of_.•••••••.•.•._.............._..............._..._.... ..... 16 


fossils or. •• _..........,. __ ............._•••• __..............._. __ ...... _. 17 


lithology of ••._......_•••••_•••.••.. _.........._......................... 16 


thickness of._ ..._................_....._.._._ •___ ._._._ .. _.'_"'_.'''.'' 16 


Fluorite, occurrence ot._........ __ ........._••••.••.•.•• _._._•...••_....._.... 112 


Fortnna claims, features of ....._........._.._•••.•_._ •• _...... __ ••_._....... 144 


Frankie mine, features ot.._._..._•• __ .........,...__ ........................ 123 


Fusselman limestone, correlation ot................_..........._.._.......__ • 18 


G 

Galena, occnrrence 01.._..... ___ •.._._ ••._. __ •• _.••••_......._............._. 111 


Garden Oity limestone, correlatIon of ___........................._........... 15 


Gardner dolomite, correlation 01._...__ ._••• _......._••_._................... 27 


Garrison Monster fault, probable conjugate faulting related to..._......._..• 83-84 


relations of. .•..•_.....•_.._.• _. __•••. __.• _•._.............. ___ ....__.•. _ 59 


Garrison Monster fault zone, nature and amount of movement along .. ___ ••• 8.~ 

relations of •. "..__ ..•_..•_•••.._•••••_•.•.•_.. __ ...._......_••. _.• _ •.• _•• _ 82-£3 

Garrison Monster mine, thin section from, showing barite replacing sulphides. pI. 11 

Garrison Monster Mining Co" claims oL•• ___ ..____ ._ .. __ .. _._........._. 164-166 


Geologic formations, age ot...._.......__ ...•......._...._.._._ .....•_._..... 4 


Geologic map and sections of Gold Hill and vicinity_..._. _•.. pI. 2 (in pocket) 

Geologic map and sections of Gold Hill qnadrangle, Utah_._._. __ pI. 1 (in pocket) 

Gerster formation, age and correlation 01._•••.•.••• _._....._.••••_._....._••• 40-41 

distribution of_ ••• ___ ••. __ ._..._. ___•.• _..•••_..•.•••_•••.•_.••••...••• _. 39 

fossils of. __._ •• _..•••...•__ .. _._ •.. _••••__•. _......_......._. _. _•.._..... 40-41 


lithology of.. _•• _.~ •• _•.. _•.•.._....._.••.__ ..• _•.._....._.••••_.._.•_.._ 39 

thickness of. ••...•...••..._•••.._•••.. __ •••. _.•••._.................._.• 39-40 

Girty, G. H., fossils identified by._ ••. '.__ " •___ •••.... _...... 26,28-29,30-31,32,33 

quoted ...._.....__ .••._..•_•••_.......... ___ .• _..._....._••• 26,32,35-36,39,42 

Gold Belt claims, features oL............. _. __ •....__ ._ ...__ ....__ ..... _._ 14~150 

Gold Bond claim, features ot. .. __ ._. ___ •.• __ .•• ____ .• _....___ . __ .• ___ ..•__ 125-127 

replacement of minerals in specimens from ....._..........._..........__ pI. 10 

Gold Hm mine of United States Smelting, Refining & Mining Co. See U. S. 

mine. 

Gold Hili mine of Western Utah Copper 00., block diagram ot._ ......_._. pI. 14 

geology of _. _•• __.• _. __ ...._..•__..••.• _..•.•.._•.._'.•'.' __ ._•. _.••••• 152-154 

level map 01.. __ ._ .•. ____ .. ___ •• __.•••• __ .•__ ...._•.•_.• __._..._. ___ • ____ pI. 15 


location, history, and development oL......__................_....... 151-152 


ore bodies ot. __._... __ ._....•...._.•..._.••..__ ••.__••••._. __ ........_. 154-156 


Gold Hill, northellSterly faults west and northwest oL...................... 77 


Gold Hill Standard Mining Co., claims oL••._._ ••... __ ••..••••.. _._....... 149 


Gold, occurrence of.._._._ ..._..........................___ •••.••.•.. _._...._ 111 


Grampian limestone, correlation ot. ..._.••.._. __ ...._._ ..._._. ___•. ____ ..._. 16 


Graphite, occurrence 01.._ •.• __ ••• _•• _........._._...... __ ••• _••••• _......... 110 


Gravel and clay, older, occurrence and character ot............_.._.. _....... 54 


younger, occurrence and character or. •••._.................._........_.. 54 


Page .. Great Blue" limestone, correlation of. _....._........._.. __ ........._...... 30 

Guilmette lormatlon, age and correlation oL..._••••. ___ ..... __ .•.. ____.•_.. 21 

distribution 01..._ •.. _.••....••••._.•••...•••.. __ ••••..••'.""" ..•. _'" 20 

fossils of. __ ••.• _..• __ ...._••_.••_......_•__ ....._•. __ •___ •••....••.•._... 21 

lithology of ....•.._.•••..._•..• _.. __ ..._. __ ._........., .•__ •.•...• _._.... 26-21 

section of. ___ .._•._•..•____ . _•• ___ .•...___ ...._••.••.. _••_____ ._•._..•... 26-21 

thickness of. __ .._.... ___ .... ____ .• __ .• _.....••• _......_. __ • _.••. _.....•• 21 

Gypsum, occurrence of. ... __ ••_..._•• _•_______ ..... ____ ._ ....._........__ ._. 117 

H 

Hartmann limestone, correlation ot. __ . ___ .. _. ___ .••._..... _____ • ___ ._.__ .._ 10 

Heikes, V. C., quoted. __._ .. __..••___ ..._._.....__ • __ ._.•_..........___ ..c.. 118 

- Hematite, occurrence of. •._...._...... __ .•.•__ ._..._.•..• _......._••._.. __ •. 112 


Herat mine, leatures of. _•. __ .• _. ___ ••. ___ ..__ . __ ••. ____ ••._.........._.. __ .• 162 


Herat shale member 01 Ochre Mountain limestone, lithology of._ ... _.• ___ ._. 30 


Herkimer limestone, correlation of ____._....._•.••. __ ...._........._......... 10 


Hicks lormation, age and correlation 01.._••••• _.••• ___ .............._•••.••_ 14 


distribution of..•.. _•••.....••._.••••..•••• _._ ....._..• _.._.............. 14 


lossils ot._...._......_•.•_........._.........._.............__._......... 14 


lithology of. __ .•._._. _......._. _. _._. __ ........_._•••.•_.. .......••.....• 14 


pisolltic dolomite from •••. _............__ ...._.•••_............_.••__ ..• pI. 5 
 r.f 

section of._ •. _._ .••...._••_..._.....____ . __ .... __ • _•. ___ •.. _._...... .•••. 14 

thickness of _. ___ .•_•.•_.... __ ._..._. __•.• __ . _••• __........._.... __ ••_... 14 


Highland Peak limestone, correlation of. ...._•. __ •••....• __ ................. 10 


Hornblende, occurrence of..... _.•• _••_..... _............................_... 114 


Humbng formation, correle.tlon 01. .• _.....••.. __ •• _.................._...... 28 


Humite, occurrence ot.. ___ ._ ..._._ .. _•.•.. _...................._......_..... 115 


Ida Lull claims, features ot. ...••_....•_.................................._.. 125 


Igneous metamorphism, features of •..•.••. _....._.................__ •••.•.__ 91-97 


Igneous rocks, older, age 01._ ..._. __ ................................._....... 48 


older, general features ot...•..•._..__ .•..._...•. __ .......___ ._........... 43 


younger, dlstribntion and relations oL__ .• _..........................._. 49 


petrography of_. _.••• __ .•• __ . __ ._ •.. ' •• '_' ..___ . __ ._....... _._...... 4~53 

Immense claim, features 01.._ ........_.• _..•.....• __._ ..••.•.. __ ..__ ••••._.. 151 


Incas group of claims, features of ..................._........................ 125 


J 

Jame&Onlte__ •.• __ ._••..••••_......................................._.••.•• 111-112 

Jarosite, occurrence oC ...._..........._.••_............__ •• _ •._._........... 117 

Jasperoid, alteration to._ .........__ ......_•••. __ .•••...•.•.•.• _•. __ ._ •.• __ •• 93-94 

calcite cleavage lines in••..••••.. _____ ._.•••. _~ ••••_..•••__ ._ ......._•..• pl. 8 


Jeiferisite, occurrence of..........._._ •. ___ •• __ .•••.__ .... .....__ .••.•...••• 115 


K 

Keno claim, features 01.....•••••._......_•.._....._••• _._._ •••__ ._ •• _._••_ 124-125 

Kirk, Edwin, fossils identified by_..._._............___ ••. __ ....._. 15,17,18,20,21 

quoted. _.•.•_.. _••...•••. __ •••.• _..•.•.. _•.....__ ...____ ....•... _.••.._. 21 

Knopf, Adolph, quoted•• _ ..••..•_•••_........................._........._... lOS 

L 

Lake Bonneville beds, occurrence and cbaracter of........................... 54-55 

Laketown dolom\ie, age and correlation oL_••.._•••...•_•..•.•.•..•_••.•.._ 18 

distribution ot.._ ..............___ • _......_._ ....._..••••• .• __ ••.••••_.. 17 r.i. 

fossils oL .•_•. '" ••••_._. _....._••• _........•__ .._.•• _•••• _.•.•••.._..... 18 


lithology of. __ ._..........._•.. _.•_•__ •••.••••, •.•. _•••••_.•••• _.... ..... 17 t 


"marble cake" dolomite near base of .._.___ .~ ..••_...•••.•___ ......._._. pI. 5 '~ .\ 


thickness ot. . ..........._._..._......_.._.••...._..........._.._...• __.. 17-18 


Lamb dolomite, age and correlation oL....._.........._.•....___ ...•.•....• 13 


distribution oc. ._....__ ....• _._ ..__ ••._. _......._. __ •• _.......,•..•_. __• 12-13 


lithology ot. _______ .•..••.••.__ ....__ ...... _......._...........__ ......•• 13 


thickness 01. . _ ... _.• _•....••.....__ ._••• ____ ............_..__ ..• __ ."'.. 13 


Langston (?) formation, correlation or. .............._....................... 8 


Latite, biotite and hornblende, petrography 01..•••••• __ ••._•••••••••• _...... 50 

biotite'augite, analysis ot. .........................._..........._._ ...._. 50 

hypersthene·augite, analysis ot. . .....__•. __ ... ____ ... ___ •.••..•..•____ .. 51 

petrogra.phy of.. ___ •••.._......_...._...._...•__........._••.....••• 50-51 

Lead Carbonate claim, features of_ .•_•.... _••._••• ___ ••• _._.• __ ._ .•••••••• 167-168 

Lincoln Highway, minor thrust east of bench mark 5684 on•. _.•••....•••... 6I}-70 

Location of the area_ ...................._._....._..........._.••.• _••.. _.... 1 

Lone Mountain limestone, correlation ot.........._........_................. 17,18 

Lucy L mine, features oL_•.....•__ ......... __ ••. __ •••._..... __ ............ 140-143 

plan of workings ot.._._ •••• _.•__ ......................................._ pI. 13 


M 

Madison limestone, age and correlation ot.. __ ..•..•.. _._ ••..•.. _..........._ 26-27 

distribution 01. _••...••••••••••...••....• _...___ ...__ ..._._ ••..._•••. ____ 24-25 

fossils of, .•••.._•.. _. ____ .._.•••.__ •.•. __ •. _., ....... __ ••.._•..•....••.• _ 26-27 

lithology 01.. ___ . __ ._ ............ _._ .••••.... _•.... __ .... _._ .•_•• _. '.'." 25-26 

variable dip of fault between, and Woodman lormation..............._•• pI. 7 


Magnetite, occurrence oC ............_.•••...••.....••..••• _........__ •• _... 112 


Malachite, occurrence oL_..••.. _. __ ..___ • ___ ......._................._..... 113 


Mammoth claims, featll!'\l\l oC••..· ............· ......· .•_····..· ......··· 148-149 


I 
___ _ 

I 

I ( 


INDEX 171 


Manning Oanyon formation, age and correlation or. _________________________ 

distribution oC ________________________________ ------- ____ --------- ___ --­

fossils 01. ____________________________________ -______ - ---------- ---------­

lithology of ______________________________________ ------ -------------- ____ plunging minor anticline in______________________________________________ 

thickness of. _________________________________________.._-- ______ --__ 

Marcasite, occurrence of. _______________________________________ ---- _______ -_ III 


Mascot claim, features or. _____________________________________ -- ___ _____ ____ 143 


Mendhe. formation, correlation 01. ___________________________________________ 13,14 


Midas mine, features of ____________________________________________________ 134-135 


Mimetite, occurrence or. ________________________________________ ----___ _____ 116 


Mineral Hill claims, features of______________________________________________ 163 


Minerals, list of, in metamorphosed rocks and ore deposits ________________ 11o--U8 


Mines and prospects- _______________________________________________ ---- __ 118--168 


Mining, outlook for __________________________________________________ ----- 109--110 


Minnehaha claims, features of _____________________________________________ 127-128 


Mississippian beds, contact of, with Pennsylvanian beds____________________ 33
 Mohawk claims, features oC _______________________________________________ 163-164 


Molybdenite, ooourrence oL___ ___ ____ _____ _________ ____ ____________ ________ 111 


Monocco claim, features of ________________________________________________ 162-163 


Monte del Rey claims, features 144 


Montoya limestone, correlstion 17
 Muscovite, occurrence 01__ ___ _______________________________________________ 115 


N 


Napoleon Mining 00., property oL_________________________________________ 125 


Natrojarosite, occurrence 01.____________________________________ - --- _______ -- 117 


Nevada limestone, correlation oC____________________________________________ 21 


New Baltimore clsim, leatures 01____________________________________________ 149 


New Year claim, features or.________________________________________________ 166 


New York clsim, features oL_______________________________________________ 143 


Nontronite, occurrence 01._________________________________________ ---------- 116 


North Pass Oanyon, plunging anticline in...__________________________________ 67 


thrust plates on north side 01.. __________________________________________ 67-68 


North Pass thrust, features 01...____________________________________________ 57-58 


relations of. _________________________________________________ ------------ 70 


warping 01-_____________________________________________ ----------------- 71 


North Pass transverse fault, relations or.____________________________________ 67 


Northwestern block, mutual relations of structural features of_______________ 88 
 structure 01___.-- __ •_____________________________________________ -------- 85-88 

o 

Ochre Mountain, crumpling beneath nearly 11at fault on west side 01._______ pI. 7 


faults 01 ftrst cycle on____________________________________________________ 55 


minor thrusts and fold on south side of _______________________________ "__ 75 
 normal faults on_ _____________ ____ _______________________________________ 75 


northward-dipping transverse faults on__________________________________ 74 
 slopes of ______________________ •______________________ -_.---.------------- pI. 6 


southward-dipping transverse laults on _______________________________ ••• 740-75 


transverse fault on south side 01_________ •_______ · ________ •·_____________ 71-72 


Ochre Mountain block, mutual relations 01 struotural features 01.. __________ 77-78 


structure 01________________________ •• ________________ ---------.---------. 72-78 


transverse fault at northern border of_.__________________________________ 77 


Ochre Mountain limestone, age and correlstion of. __ ••••_______ __ •_________ 30-31 


distribution of________________ . ___________________________ •.• __ ---------- 29 ­

lossils of. _____________________________________________ -------.----------- 30--31 


~~~~::s ~-:__:____________ :::::::::::::::::::::::::::::::::::::::::::::::::::: 29-: 

wollastonite replacing garnet in metamorphosed ___ •_____ •_____ , _________ pI. 8 


Ochre Mountain- thrust, appearance 01. _____________ • _______________________ 71h'lO 


exposures of, east of Lincoln Highway._____ . __ •.•______ ·________________ 78 


features of _________________ • __________________________ -----------.---- 57-58, 59 


!~i~:~ :_~~~~_~~~~~t_~::::::::::::::::::::::::::::::::::::::::::::::::: ~ inftuence of, on distribution of ore deposits----_ ..------------------_---- 108 

:::~~!~~-~i'-.-::__ ::::::::::: ::::: :::::::::::::::::::::::::::::::::::: ;;~ minor structural features in rocks above ____ •____. ______ •________________ 84-85_ 


northwesterly normal faults east of main outcrop 01..____________________ 76-77 


relations of _____________ •_____________________________ ------------------- 71 


along north edge of Dutch Mountain ______________________ •___ ·_____ 79 


between Pool Oanyon and Garrison Monstsr mine __________________ 78-79 


:!~la~~:O~~~~t;-~;;;___-_____~~:::::::::::::::::::::::::::::::::: ~: south of Pool Oanyon _______________ •___ •________________________ ·__ 78 


thrust plates associated with__________________ . ___________ ·_____________ 79 


south of Pool Oanyon fault, laulting below _____________ .________________ 81 


warping of_________ ._. _______________________________ -------------------- 71 


"window" west of main outcrop 01._____________________________________ 73 


Ochre Springs, transverse fault north of_____________________________________ 713 


Oligoclase, occurrence 01. ___________________________________ --_-------.-.---- 113 


Olivenite, occurrence of. _______ •________________________________________ ----- 116 


Opal, occurrence of _____________ • ______________________ • __•________ ---------- 112 


Opex dolomite, correlation ot._______________ ••_.____________________________ 13 


Ophir shale, correlation of ______________________________ •___ ••________ ·______ 7 


Page 


32-33 


3i-32 


33 


32 


pI. 7 


32 


Page 
 Opohonga limestone, correlation 01.. _________________________ • _____________ • 15 


Oquirrh formation, age and correlation 01.. ______________________ • ___________ 35-39 


alteration of replacement bodies in__ •._______. _______________ .___________ 107 


chert-pebble conglomerate with oolitic matrix from ____________ • ______ • __ pI. 5 
 distribution of. __________ • ___________________________________. ______ •• ___ 33 


fossils of_________________________________________________________________ 31>-39 


lithology 01. ___ • ________________________________________________________ • 34-35 


thickness 01.. _______________________________ . ____________________ • _____ _ 35 


Ordovician beds, unconlormity at base 01 Upper---------------•• --.--------- 16 unconformity at top of Upper___ ._______________________________________ 17 


Ordovician system, formations 01- ____ . _______________________ • __ . ___________ 15-17 


Ore deposits, areal relstions 01. ____________________________________________ 107-108 


classification of _________________________ ..______________________ .____ ____ 97 


genesis of __________________ . ____________..__________ . _" _______ •________ 108-109 


intJuence of zoning on distribution 01. ___________________ • ____ • _________ 107-108 


Oregon claims, features 01. _______________________________ • ___________ ._ _____ 162 


Orpiment, occurrence 01. .._____________________ ..___________________________ - 111 


Orthoclase, ooourrence ot.__ _______ . ________.._____ ______ ____ ________________ 113 


Overland Oanyon, faults east 01..____________________________________________ 69 


normal faults north of_____ _ _ ___ ______ ______ ____ ______________ __ __ _______ 71 


transverse fault north of __________________________ •_____________ •________ 70--71 


Ozark claims, features 01. __________________________ . _______________________ ._ 128 


P

Pay Rock claims, features of ___ •_______________________________ ..____________ 150 


Pharmacosiderite, occurrence of _______________ ._____________________________ 117 


Physical features of the area__________________________ .__ ____ ____ _________ ___ 1-2 


Pine Canyon limestone, correlation 01.__ . _______ .__ __ _______________________ 27 


Pioche shale, correlation 01._._________________ ____ __ __ ______________________ 7 


Pipelike deposits, alteration 01. ________________ •• ____ ______ ___ ___ _____ __ __ ___ 105 


features 01. ______ •_______________________________________________________ 97-99 


mines and prospects in________________________________________ . _______ 119-123 


Pliocene(?) sediments, occurrence and character 01. __________________________ 48--49 


Plumbojarosite, occurrence of ___ •__ . _________________ ._______________________ 117 


Pogonip limestone, correlation 01. ________________ • ________ ._________________ 16 


Pole Star Oopper Co., claims of __________ • __________ •_____________________ 124-126 


Pool Canyon transverse fault, features of. __________________ . _______ ._. ___ 57,58,80 


relation 01, to North Pass thrust______________________ • __________________ 80-81 


Powellite, occurrence of. ________________ . ___________________________ ._____ __ 118 


Pre-Carboniferous sedimentary rocks in eastern Nevada and western Utah, correlation 01____. ______________________ . ________ . ___________ ..__ 23 


Prospect Mountain quartzite, age and correlation of_. _________ ._____________ 6 
 distribution 01..____ __ ___ ____ __________ ____ ____ _ _ _ ___ __________ ____ ___ ___ 4-5 


lithology of _______________________________________________ . __ -_____ __ ____ l> 


section of. _______________________________ . _____.. __ ._ __ ___ ___ ____ __ ___ ___ II 


shale members of ___________________________..________ _____ __ __________ __ 6 


thickness of ______________________ .•______________________________ •_____ __ 6 


Pyrite, ooourrence of. ______________________________________ • _________ ._ ___ __ III 


Pyroclastic rocks, petrography oC _____ • ___________________ •_________________ 52-53 


Pyromorphite___ ._.____ . ________________________ ._.__________________ -______ 116 


Pyrrhotite, occurrence of ______________________ . _______________________ ._____ 111 


Q 

Quartz carbonate vein east of Clifton, specimen from ________________ . _______ pI. 10 


Quartz monzonite, alteration 01..__________ . ___________ - _____________________ 94-96 


areal extent 01. ____ . ________________ . ______________ - - - ___ -_ - ------------- 43-44 


chemical analysis 01. ________________________________________________ ._ __ 44 


comparison of alteration 01, with alteration of sedimentary rocks _________ 96-97 


factors inftuencing the localization 01.. _________ . _________________________ 45-46 


petro~raphlc and chemical character of. ______ • _____________________ . ____ 44-45 


silicifted, elon!!ated quartz grains in___ . _________________________________ pI. 9 


structural features not related to emplacement or cooling 01.. _____ . ______ 89-91 


structural features related to solidification of ___________ ..________________ 89 


Quartz monzonite block, laults.related to emplacement 01.. _______________ • __ 88-89 


structure 01.. ______________________________ . ____ -- ___ ----. --------------- 88-91 


112 


Quartz-sulphide veins, alteration 01____ . ______________________ ·______________ 105 


leatures of. _______ . ___________________________________ -__ -___ ------------ 101 


mines and prospects in __ . ___________ . ___________________________ ------ 140-151 


outlook lor mining ___________________ . _______________ --- --- ------------'- 110 

Quartz, occurrence 01._____ - - - ----- --- ---- ---- - -- ----- - - --. -----------------­

R 

Rea claim, features oC____________________________________________________ - 150--151 


Realgar, occurrencc of. ___________________ . ___________ ----_ ----------.--.---- 111 


Reaper claims, features of. _____________________ . __ . _________ -------------- 119-121 


specimen from tungsten-bearing pipe on _________________ • _______________ pI. 9 


Red Jacket claim, features of ________ . _________________________ • _____ ----- --- 148 


Reeside, J. B., Jr., fossils identified by:_____________________________________ 43 


Replacement bodies, arsenic, alteration of ______ • __________________________ 108-106 


arsenic, features oL ___________________________ . _____ ---- __ ------------ 102-103 


mines and prospects in. ________ • ______________ ..__________________ 151-162 


outlook for mining. ___________________________ . _______ . ____ ---- ------ 110 

barite, aiteration of ________________________________________ ---------.---- 107 

copper-lead-silver, alteration of.. ____________________ , _________________ lOCI-1M 

1 
DEC 3 1958 


172 INDEX 

R"eplacelIlllnt bodies, copper·lead·silver, features '.1," . 

mines and prospects in............................ 'G~'(; 

outlook for mining .•••••••••••_••••••••.••••_•••_.................... 110 


Resser, O. E., fossils identified by•.•••••••••.......•.•.•••••••••••••••..•••• 10,14 


Rhyolite, partial analysis of ••c~::.....~...................................... 51 


Rhyolite, petrography of••• ••..•••••••__ •••••••_............................ 51 


Royal Gulch, "window" in••••••••...••...•••••••.___ . _______.•_._ ••_•••• __ 79 


"window" in, faults in._ •• ___ ._._ •.••••••••••••••••••••_._ •••••••••••••• 81-82 


Rube mine, features of ••• _••••••••••••••.••••••:••••••••••••_. __. __ ••••_ •• 13&-138 


Rutile, occurrence of_. _••• __ ••••••_••••••___ •___ •••••••.••••••••••••.....••• 112 


S 


sani":K:. No.1 claim, features of ••••••••••.•••••.....••••••••••••••••_........ 151 


Scepolite group, occurrence of ••••••_•• __ ••_••••• ___•.•.....••_•••••• __ .•...• 114 


Scheellte, occurrence of. ___ •__•.._...••••••••••... .....••••••••_••••••.... 117-118 


Scorodlte, crystalUne, forming from metacollold•••••.••....•••••••••••••••••• pI. 12 


occurrence of .......................................................... 116·117 


Searchlight cla.lm, work on.................................................. 163 


Secret Ca.nyon shale, correlation 01.......................................... 14 


Sedimentary rocks, alteration 01..•••••••••••••.•.•••••••••••••••••.•.•.•.••• 91-94 


comparison of alteration of, with alteration of quartz monzoniUt.••••••••• 9&-97 


recrystallization 01.......••••••••••••••••••..••••••••••••••••••••.•.••••• 91-92 


Sericitization, alteration of quartz monzonite by............................. 95 


Sevy Ca.nyon, strncture in, south of Blood Oanyon faulL................... 67 


transverse fault In, relations of .•••••••••••••••••_........................ 66-67 


Sevy dolomite, age a.nd correlation oC...................................... 19 


distribution of .......................................... ••••••••••••••,. IS 


lithology of .•••••.__ ••••••._••••••••••.•••••••••••••••••.•.•.•••••.• ..... 18-19 


thickness of. ••..••••••••••••••••••••••.••.•.•••••••••.•.•••.•...•...••••• 19 


Shay cla.tlDll, featuresor................................... __••.•._........••• 149 


Siderite, ooourrence of. ...•••••••••""""" ..•••••••••• ____•••••••..•.••••• 113 


Siderotll, occurrence of ........................................_____ •._...••• 117 


SUlcate·gangue veins, alteration of._. __ •••••_." ••••••_•••••_••••••••. __ .._... 105 


features 01.••_•••••••..••.• ____ ••••••••••••••••___ . __....._._ ••••••.••_. 99-101 


mines and prospects 1n., .•••.•__..______ ••.•••....... c •••••••••••••••• 123--138 


outlook for mining ..................................................... 109--110 


SlIIcate minerals, alteration to .............................................·,. 92-93 


Silicification, alteration of 'laartz monronlte by.••••• _....................... 9&-96 


Silurian beds, unconformity at top of........................................ 18 


Silurian system ••••.....•••••••••••.••••••..•..••••••••••••, •••••••.•.••••••• 17-18 


Silver &: Gold Mining Co., Inc., claims of, features of........................ 143 


SUver claim, features of ••••.......••••••••••...•....•••_...._c............... 168 


Silver King claIms, faatures oL.................................._.......... 163 


Simonson dolomite, age a.nd correlation ot............................_...... 20 


distribution of._...........••.••••••••..............•.••••............... 19 


fossils of_••.• ........._•.••••..•.•••••••.•••••••••••.....•••.•••••••_... 20 


lamlnated.••••_..............................."" ••.•.•.....•.•.•••_... pI. 5 


lithology oL...........................................................,. 19 


section of.. ...•.•.••••••••••••••••.••••••.••••••••••••••••••••....••••••• 19 


thIckness of ..•"'" •••_.......__._...............•••••••••.•••.•••.•.••• 20 


Smithsonlte, occurrence 01....•.••••••••••....•.•.•••••••••••••_.........•••. 113 


Southern Confederate claim, features of ••••••••_•...••••••• __ ••••••••••_••• 147-148 


Spadalte, occurrence of ••••_...............................................". 115 


wollastonite replaced by..............................................._. pl. 8 


Sphalerite, occurrence of.••••••••••••••••••••••••••••••••••..•_.............. 111 


Spinal, oocmrence 01.................................. ~ .•.•.•.•...•••.•_••• __ 112 


Spotted Fawn cla.ims, features of •..•••.•••••••_••••••••••••••_.••••••••••• 145-146 


Spotted Fawn fault, faults beneath thrust north of••••••••••••••••••_....... 82 


minor faults between Pool Canyon fault Md.•••••••••_................. 82 


relations of •••..•.•••.••••• _•• " •••••••••••••••_........................_. 56 


Spotted Fawn normal·fault zone, features ot. •••••• _•.•..._.•.•.•••.•_._.__•• 81 


Stibnite, occurrence of •• _ .•.....•••••••••••••__ ..••••••••••.•••••••••••••.•.• )11 


Stolzite, occurrence of..•.•••••.•............••••••••••••••••••••••••••••.••• 118 


Strnctural cycles, stages of •••••••••__ ...•••••••••••_..............._•••_.•••• 65-61 


Strnctural features, age of •••••.• c ..................................._••••••• 63--84 


correlation ot. •••••••• __•••••••••••.•••.•. •••_••••••••••• _ •.•••.. __ .._... 66 


local descriptions of_•••••••••_........................................... M-1l1 


Success mine, features of..................................................... 145 


Sulphur, ocoorrence oL__~.................................................. 110 


Sunday claims, features of .••.•.•_••_••••••.••••••......_.................... 167 


T 


Talc, occurrence of ••• _ •• _ ........................._......................•••• 116 


Tank WRSh fault, relations oL~•••c.·-•••-••••••••••••••···•• _ •••_·••__ ••••• 56,86 


Tennantite, occurrence or.................................................... 112 


Tertiary system, formations or. ••••••.•••..•••••••••••••••.•.•.•••••••••••••• 42-48 


Tetrahedrite, ocoorrence of ••••••••••.•••••••_............................... 112 


Teutonic limestone, correlation of ••••••••••••••_••••••••••••••••••• __ .••••••• 10 


Tintic quartzite, correlation 01..•••••••••". _ .••••.••.•••••••••••••.•_ ••••_. 1\ 


Tlta.nite, occurrence of ..............._••_.................................... 116 


Pall'e 

. (maline, vccurrence of ..••••••••• __ ••••••••••••••••_••••••••••••••••_.... 118 


il ;hyte, r~rtial analysis of..........•••••••••••••.•.•••••••.••••••••••••••• iiI 


petrography of.......................................................•••• iiI 


Trail Gulch fault, rela.tlons ot..••••.••••••••••••••••••••••••••••••••••••••••• 56,84 


Tremolite, occurrence of •••.•••••••.•...•.••.••••••••••••••.••..•••••••••••_. 114 


Triassic limestones, Lower, occurrence andfassils of •••••••••·_............... 42 


Trippe limestone, age and correlation of •••.••_•••••••••••_•••_••••••••••••_. 12 


distribution of.......••••••••••••••••••••.•.•....•••••••••••••••••••••••• 11 


laminated............................................................... pI. Ii 


lithology of ••.•••.••..••..•••••••••••••••.•••••••_••••••••••••••••••.•••• 11-12 


section of.....•••.••••••...••••••••••••••••••••••••••••••••••••••.•.•••.• 12 


thickness of...••••••••••••••.......••••••••.•.•••••.••••.••••••••••••••• 12 


Troy claim, features 01...................................................... 151 


Tungsten, outlook for mining................................................ 109 


Twin Peaks, recumbent anticline on•••••..•..••••••••••••••••••••••••••••••• 56,86 


U 

Uiyabl Oanyon block, structural features of.. ..••....•••_•••••••_ •••••••••• 69-72 


Uiyabi Oanyon, minor foMain .•_••••••••••••.•....••••••_.................. 70 


Uncle Sam claim, features 01..•••••••••__ •••_••••••.••.••••••••••••••._...... 166 


Undine claims, features of.................................................... 150 


U. S. mine, bla.ded arsenopyrite h-om .Tunnellevel oL•••••••••••••••••••••• pI. 11 


faults near ..•••••••••••••••••••_••••••••••••••••••_...................... 76 


geology of. _•••.••.••••••••••••••••••.•.••••••••••••••••.••••••••••• "_ 156-100 


Jasperold from, with inclua.toDll of opal in quartz•••••.•.•••.•.•.•.••••••• pI. 8 


location and development of •••••••••••.••• __ ••.••••••.•••••••••••• __ •• 156-158 


ore 01.••••..•.•••.••_•••_•••••••••••••• _•• __ ••••••••••••••••••••••••••• 160-162 


polished sectIon from, showing brecclated arsenopyrite veined by pyrite, 


quartz; sphalerite, and galena•...•....••••••••••••••_••••••••••• pI. 11 


structural featares east of •• _ •••••••••••••••••.•_.•••••••••••••••••••••••• 7&-76 


V 


Vegetation...._•••••••••. ' •• "'._'.'••••••• _••••••••.•..•_.................. 3 


Vesuvianite, occurrence 01." •••••••••_•.•.__ ••_.............................. 114 


Victoria quartzite, correlation of .•_••.•••.••••••••••••••_.................... 27 


Victory No.1 Claim, featuresof•••••••_....................................... 127 


Volcanic rocks, age oL•..•..•: ••••••••••••.••.•......••_••••••••:•••••••••_.. 58 


alteration of .••.......••.••••••••••••......••••••_••••._•••••••••••••,... 58 


W 


Wad, occurrenoc of •••••••••••••••• _••••.••••••••••••.••••• •••••••••••••._.. 112 


Walla Walla cla.im, features of .••••••••••••_•••••••••••.•••••••••••_......... 164 


Wells, R. 0., chemical analysis by........................................... 44 


Western Utah Extension Oopper 00., claIms of ••••••••••••••••.••••••••••• 146-147 


Western Utah mine, polished section from, showing replaeenlent of Ill'IKlIlOpyrite fragments by quartz and serlcite••••••••••.•••••_......... PI. 11 


specimens of scorodite from .•••••••_••••....•••••••••••••••••••••c••••••• pl. 12 


structural features in vicinity of •••••••••_•••.•_......................... 77 


White Sage formation, age and correlation of................................ 43 


distribution of •••..••.•......• __ •••••••••••••••••.•.••• cc•• 0' ••••,....... 
 42


fossils oL .•.•••••..••...•.•.• _•••...•••••..••_............•••••••••••••••• 43 


lithology of .•.••••_••••..............•••••••••••.....••...•.••••••••••••• 42-43 


thickness of•••_••••••••• 0 ••• _ •••••••••••••••••••••••••••••••c............ 43 


unconformity above •.•••••_............•...•••••••••••••••••••••• ••• •••• 43 


Willow Springs district, history and productions of.......................... 167 


prospects oL•.••...•_••_.•••_•••••••••....._••••_•••.••••••••••••••••• 167-168 


Wilson Oonsolidated mine, features of •••••..••••_•••.•.•••.•.•••••.••_. __• 138-140 


quartz and orthoclase replacing Calcite in•....••.••••••••••••••••••••.••• pl. Ie 


Wolframite, ocqurrence of .••••••••••••••••••...••••••••••••••••••••_••••••_.. 117 


Wollastonite, occurrence of. ••••••• _•••••_•••• •••••••••••••••••••••••••••• 113--114 


Woodman formation, age and correla.tion of ••••••••••...••••••••••_•••_••••• _ 28-29 


distribution of..••••••••••• "'_.•••••_••••••••••••••••••••c ••••••••••••_. 27 


fossils of .••.•••••••.••••••••••••••..•_•••••••••••••••••••••••••_••••••••• 28-29 


lithology of •.••••....••••••_............•.•.•••••••••••••••••..•••••••••• 27 


minor thrust in, north of Garrison Monster new camp•••.•.••••••••••••• pl. 7 


section 01.. _•••••••••.•.•.•••••••••••••••••••••__••••••••••••••.•••••_... 28 


thickness' of •._•••••.•.•.•.•.•••_......•••••••••••••••••••••••••••••.••••• 28 


Wulfenite, occurrenoc of ..••••••.••••_....................................... 118 


Y 


Yellow Hammer cIa.tms, features of •.•••••••••••••_..••••••~................. 122 


Yellow HilI limestone, correlation oL..••• _•.••••.••_....................... 16 


"'Young Peak dolomite, age and correla.tion of. .•••••••••••••••••....__••••••• 11 


distribution 01.._.•__ ••••••••••••.•.•.••••••••: ••••••••_...........•••••• 10 


lithology of ••••••.••••..• ____ ••••..•.•••_.•__•••••••••••••••••••••••••••• 16-11 


mottled••.••••............••_••••••••••••••..••••••••••••••, .•••....__ .• pl. 5 


Z 

Zircon, occurrence of_*"'..... _________ .. ________ .. ______ .. _______ .. _.. _.. __ ... _______ .- ":14 

Zoisite, occurrence of. ........."""""" •••_.•..•_.•.•••.....••••_•• 


o