Lake Bonneville:

i

Geology of Southern 

Cache Valley, Utah

GEOLOGICAL SURVEY PROFESSIONAL PAPER 257-C
Lake Bonneville: 

Geology of Southern 

Cache Valley, Utah

By J. STEWART WILLIAMS

GEOLOGICAL SURVEY PROFESSIONAL PAPER 257-C

Cenozoic geology of a part of the area 

inundated by a late Pleistocene lake

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1962
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington 25, D.C.
CONTENTS

Abstract-__-_-__-____-_____--_-_-_-________-_-_____

Introduction.______________________________________

Stratigraphy.______________________________________

Pre-Tertiary rocks_______-_-_-_-_-_-_.__________

Tertiary system. _______________________________

Wasatch formation__________________________

Salt Lake formation...______________________

Lower conglomerate unit________________

Tuff unit.---_-----_---------------_--_

Upper conglomerate and sandstone unit___ 

Quaternary deposits.._____---____-__--_____-___-

Pre-Lake Bonneville deposits-________________

Fan gravel-_-_-_-----___-_--____-_-____

Concealed deposits._____________________

Landslides _____________________________

Lake Bonneville group. _____________________

Alpine and Bonneville formations, undifferentiated__ _ ________________________

Gravel. ___--_-_____-_______-_____-

Silt and fine sand-__________________

Provo formation._______________________

Gravel and sand member. ___________

Silt and clay member___________-_-__

Page 

131

131

132

132

132

132

133

133

134

134

135

135

135

135

136

137

137

137

139

140

140

142

Page 

Stratigraphy—Continued

Quaternary deposits—Continued

Landslides of Lake Bonneville and post-Lake

Bonneville age____________________________ 142

Post-Lake Bonneville deposits________________ 142

Fan graveL____________________________ 142

Flood-plan alluvium_____________________ 142

Alluvial sand in natural levees of the Bear

River----.-----------.-------------- 142

Slope wash___________________________ 143

Eolian sand________-__--_-_--___---__-_ 143

Spring tufa cones _______________________ 143

Interpretation of well logs. _ _________________ 143

Outlet of Lake Bonneville at Red Rock Pass.__________ 143

Structural geology. _________________________________ 146

Engineering geology_______-____-_-_-_-___--_--__-_-- 148

Ground water._________________________________ 148

Construction materials.___________-____-__--__-_ 149

Engineering applications-.----------.--.-.------- 149

References cited..__________________________________ 150

Index._____-_____-__-___-_____-__-_-_-__--_---_--. 151

ILLUSTRATIONS

PLATE 6. Geologic map of southern Cache Valley, Utah_________________________________-___-_------_------ In pocket

7. Generalized isopiestic map of Cache Valley._____-___-_________________________----------_--__------ In pocket

	Page 

FIGURE 38. Index map of Lake Bonneville___-____________-______-_____--_____-__---_---_-----_----------------- 131

39. Diagrammatic cross section of Cache Valley_-__----------_-----_-------------__------------------------ 136

40. Embankments of gravel of the Alpine and Bonneville formations at Wellsville___--------------------------- 138

41. Eroded embankment of silt and fine sand of the Alpine and Bonneville formations_____________-__---_------ 139

42. Sterling bar of gravel and sand of the Provo formation.__________________________-_--__---_--_----_----- 141

43. Correlation of lake beds in Cache Valley between Cornish and Lewiston.______________-_____--_-____--_--- 144

44. Correlation of lake beds in Cache Valley between Cache Junction and Smithfield- _____--____---_---_-__---- 145

45. Correlation of lake beds in Cache Valley between Richmond and Smithfield--_________--_--_--__----------- 146

46. Correlation of lake beds in Cache Valley southwest of Logan________________---_-___-----_--------------- 147

47. Correlation of lake beds in Cache Valley from Logan toward Wellsville_______________----_---------------- 148

TABLES

Page 

TABLE 1. Paleozoic formations in the mountains adjacent to southern Cache Valley__-______________---___--.--__----- 132

2. Past usage in stratigraphic nomenclature in the Salt Lake formation in Cache Valley, Utah and Idaho. _______ 133

3. Particle-size composition of silt and clay member of Provo formation._____________________---------------- 142

LAKE BONNEVILLE: GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH

By J. STEW ART WILLIAMS

ABSTRACT

This report, covering about 450 square miles in southern 

Cache Vally, Utah, is one of a series dealing with the geology 

of Pleistocene Lake Bonneville. The report summarizes in tabular form the Paleozoic formations that are exposed in the 

mountains adjacent to Cache Valley amd describes briefly the 

Tertiary formations—the Wasatch and Salt Lake formations— 

which are exposed in the valley. Most of the report deals with 

the Quaternary deposits.

Fan gravel and landslides of pre-Lake Bonneville Quaternary 

age are exposed in a few places at the edges of the basin, and 

well logs indicate a deep fill of this age in the subsurface 

of the basin interior. The sediments of Lake Bonneville 

comprise the Lake Bonneville group. The oldest of the unconsolidated deposits are the Alpine and Bonneville formations, 

which were mostly mapped together in southern Cache Valley. 

These formations are composed mostly of silt, but they include 

some gravel in embankments and small deltas. Their thickness 

ranges from about 50 to 100 feet.

Overlying the Alpine and Bonneville formations is the Provo 

formation 50 to 75 feet thick. In Cache Valley, as elsewhere in 

the Lake Bonneville basin, the Provo includes extensive gravel 

deposits in bars, spits, and deltas. It is the surface formation 

in much of Cache Valley. Deposits younger than the Provo, 

mostly of Recent age, include alluvial flans, flood-plain alluvium, 

natural levee deposits along the Bear River, slope wash, eolian 

sand, and cones of spring tufa. Several faults, active in Tertiary time, are mapped.

Well logs indicate that the pre-Lake Bonneville deposits of 

Quaternary age are surprisingly thin in Cache Valley, suggesting 

that the valley had exterior drainage during mostof Pleistocene 

time. The logs show two main aquifers of gravel and sand— 

the upper one between the Provo formation and the Alpine 

and Bonneville formations and the other directly beneath the 

Alpine and Bonneville deposits. These aquifers probably are 

alluvium deposited during interlake intervals.

The shore embankments and deltas of the Lake Bonneville 

group are abundant sources of gravel and sand for construction. Much of the gravel is suitable for concrete aggregate.

INTRODUCTION

Cache Valley is a narrow elongate basin lying at the 

northeast corner of the Great Basin (fig. 38). The 

northern half of the valley is in Idaho, the southern 

half in Cache County, Utah. This report covers the 

Utah part of the valley, which extends over approximately two-thirds of two 15-minute quadrangles constituting the west half of the 30-minute Logan quadrangle.

FIGURE 38.—Index map of Lake Bonneville showing the areas covered 

in Professional Paper 257. 1, Northern Utah Valley (chap. A). 

2, Southern Utah Valley (chap. B). 3, Cache Valley (chap. C). 

Red Rock Pass, outlet of the Pleistocene lake, is at the north end of 

Cache Valley in Idaho.

The interior of Cache Valley is covered mainly by 

deposits of former Lake Bonneville. In the foothill 

areas around the valley Tertiary rocks of the Salt Lake

131
132 LAKE BONNEVILLE

formation, aggregating several thousand feet thick, are 

fairly well exposed. The higher mountains bordering 

the valley are composed of Paleozoic rocks.

Mapping was begun in September 1946 and was continued intermittently until June 1948. About 200 days 

of fieldwork resulted in mapping about 450 square 

miles. The base map is a planimetric compilation from 

aerial photographs. Geologic boundaries were drawn 

in the field on acetate overlays covering the photographs and subsequently transferred to the base (pi. 6).

STRATIGRAPHY 

PBE-TEBTIABY BOCKS

Paleozoic rocks aggregating more than 30,000 feet 

thick are well represented in the mountains adjacent to 

southern Cache Valley. They were the source of most 

of the detrital material that makes up the Tertiary and 

Quaternary deposits in the valley. The most abundant 

rock type is sandstone, followed, in turn, by limestone 

and dolomite. The Paleozoic formations are summarized in table 1.

TABLE 1.—Paleozoic formations in the mountains adjacent to southern Cache Valley

[After Williams, 1948]

System

Pennsylvania!!

Mississippian

Devonian

Silurian

Ordovician

Cambrian

Formation

Wells formation ———— Unconformity ———— 

Brazer limestone

Madison limestone

Jefferson formation

Water Canyon formation

Laketown dolomite

Fish Haven dolomite

Swan Peak formation

Garden City limestone

St. Charles formation

Nounan dolomite

Bloomington formation

Blacksmith dolomite

Ute formation

Langston formation

Brigham quartzite

Lithology

Brown- weathering calcareous sandstone and gray limestone____ __

Gray limestone and silty limestone, and black shale and black 

phosphatic shale.

Thin-bedded fo&siliferous gray limestone; some black shale near 

base.

Thin-bedded buff sandstone and siltstone, and dark-gray dolomite 

and limestone.

Thin-bedded buff, sandy and silty dolomite, sandy shale and 

sandstone.

Dark-gray thin-bedded limestone and shaly limestone, weathering 

olive buff.

Massive gray dolomite and thin-bedded limestone; drab quartzite 

member at base.

Neutral-gray dolomite and dolomitic limestone, generally massive.

Citrine-drab shale interbedded with brown-weathering sandy and 

silty limestone, gray oolitic limestone, algal limestone, and intraformational limestone breccia.

Gray dolomite, tan- weathering; black, green, and gray shale ; some 

limestone.

Thickness (feet)

1, 000-6, 140+

1, 500-3, 700

845

0-2, 120

150-540

1,510

140

340

1,400

1, 015-1, 130

825-1, 125

1, 050-1, 500

325-800

665

310-485

1, 800-4, 800+

Probably a considerable thickness of Triassic rocks 

and also some Jurassic sediments were deposited over 

the Cache Valley area, but these were removed when, 

near the close of Jurassic time, northwestern Utah was 

raised in a broad geanticline. This uplift held the 

Cretaceous shoreline east of the future site of Cache 

Valley. The rise of this ancient landmass may be considered the onset of the Laramide orogeny which completed destruction of the Cordilleran geosyncline by 

folding its sediments into a great mountain system. As

a result of the Laramide orogeny the rocks in this region 

were folded and broken by thrust faults. Broad anticlines and synclines were formed in the mountains east 

of Cache Valley.

TERTIARY SYSTEM

WA.SATCH FORMATION

A few tiny exposures of conglomerate and sandstone 

on the western side of Cache Valley are assigned to the 

Wasatch formation. Two small areas on Wellsville
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 133

Mountain are pebble and cobble conglomerate, with a 

matrix of coarse red sand. Here the Wasatch deposits 

are unconformable upon the Paleozoic strata and are 

overlain by the younger Tertiary rocks of the Salt Lake 

formation. The pebbles and cobbles are mostly sandstone, calcareous sandstone, and limestone from the 

Carboniferous formations. Another tiny area on Newton Hill is conglomerate composed of subangular fragments of pebble and cobble size (90 percent of the 

rock), derived from the Madison, Water Canyon, and 

Wells formations, in a red matrix (10 percent) of sand 

and calcium carbonate. In the extreme southern end 

of the mapped area are several unmapped exposures 

of soft reddish sandstone, beneath limestone of the Salt 

Lake formation, that are tentatively assigned to the 

Wasatch formation because of their color. These exposures occur west of Paradise in Tps. 9 and 10 N., R. 

1 E., in the short north tributary to McMurdie Hollow, 

NWi/4 sec. 30, T. 10 N., R. 1 E.; in Big Spring Hollow, 

NE% sec. 6, T. 9 N., R. 1 E.; and in the West Fork of 

Big Spring Hollow, NEi/4 sec. 7, T. 9 N., R. 1 E.

SALT LAKE FORMATION

The light-colored poorly consolidated rocks that crop 

out in Salt Lake and Morgan Valleys, 50 to 100 miles 

south of Cache Valley, were named the Salt Lake group

by Hayden (1869, p. 92). He thought them to be of 

late Tertiary age. Similar rocks were discovered 

shortly thereafter by Peale (1879, p. 588) in Cache 

Valley, Bear Lake Valley, and other valleys in southeastern Idaho. Mansfield (1929, 1927) designated and 

mapped similar rocks in southeastern Idaho as the 

Salt Lake formation of Pliocene (?) age. Later workers in northern Utah and southern Idaho have continued to use the name Salt Lake formation (or group) 

for these diverse volcanic-derived rocks. They have 

variously considered them to be partly Oligocene 

(Eardley, 1944), mostly or entirely Miocene and Pliocene (Adamson and others, 1955; Slentz, 1955), and 

probably Pliocene (Hunt, 1953; Bissell, 1962).

Rocks of the Salt Lake formation are widely exposed 

in the pediments and foothills around the margins of 

Cache Valley in an almost continuous belt that commonly is 1 mile or more wide and in places 2,000 feet 

above the valley floor. A comprehensive discussion of 

these rocks over the whole of Cache Valley has recently 

been published (Adamson and others, 1955). They are 

here divided into three units, from oldest to youngest— 

the lower conglomerate unit, the tuff unit, and the upper 

conglomerate and sandstone unit. Table 2 shows the 

correlation of these units with those previously named 

by other geologists who have published on this area.

TABLE 2.—Past usage in stratigraphic nomenclature in the Salt Lake formation in Cache Valley, Utah and Idaho

Williams (in Smith, 1953)

A

3

8

so

<D •a ^

102

Cache Valley formation

West Spring formation

Collinston conglomerate

A. S. Seller (1952) 1

Mink Creek 

formation

Conglomerate 

member

Tuff member

Adamson and others (1955)

§• 

1

C5 M 

03 

J 

-M"08 

02

Mink Creek conglomerate

Cache Valley formation

Collinston conglomerate

Present report

090

Lake Saltformation Upper conglomerate and 

sandstone unit

Tuff unit

Lower conglomerate unit

1 Geology of the Mink Creek region, Idaho: Unpublished master of science thesis, Utah Univ.

LOWER CONGLOMERATE UNIT

The lowermost unit of the Salt Lake formation in the 

Utah part of Cache Valley is here designated the lower 

conglomerate unit. It consists of boulder and cobble 

conglomerate having a white matrix, distinctive from 

conglomerate of the Wasatch formation, which has a 

reddish matrix. This unit crops out in the foothills 

near Mendon and Wellsville, on the southwestern side 

of Cache Valley. It apparently is continuous with a 

conglomerate unit in the lower part of the Salt Lake 

that crops out in a belt about a mile wide around the 

northern end of Wellsville Mountain from Mendon to 

Collinston (outside the mapped area), that was previously designated the Collinston conglomerate (Williams, in Smith, 1953; Adamson and others, 1955). 

West of Mendon and outside the mapped area the conglomerate is thinly mantled by loose round stones and 

is too poorly exposed to show its exact attitude, but it 

appears to dip valley ward more steeply than the present 

ridge crests. Assuming a 30° dip and no repetition by 

faulting, the unit is about 2,500 feet thick; however, the 

dip may be less and the unit correspondingly thinner; 

also it may be faulted. A boulder conglomerate tentatively correlated with this unit is exposed about 3 miles 

west of the mapped area in the bank of the West Side 

Canal, near Wheelon, in the SW1^ sec. 27, T. 13 N.,
134 LAKE BONNEVILLE

R. 2 W.; it overlies Paleozoic dolomite and contains 

large fragments of conglomerate of Wasatch age.

Traced from the north end of Wellsville Mountain 

into the mapped area, the conglomerate unit is believed 

to underlie most of the foothill belt between Mendon 

and Wellsville. It is mantled with loose cobbles and 

pebbles, but the hummocky undulatory surface suggests 

weak bedrock rather than Quaternary fan gravel.

Southeast of Wellsville, a boulder conglomerate, presumed to be this unit, underlies both the low ridge in 

sees. 14 and 23 and the arcuate hill in sees. 1, 2, 11, and 

12, T. 10 N., R. 1 W. In the ridge the conglomerate 

overlies calcareous sandstone of the Wells formation. 

On the hill there is no clue to the material that underlies 

the conglomerate. At these localities the conglomerate 

is composed largely of cobbles and boulders of sandstone, calcareous sandstone, and cherty limestone from 

the Wells formation, and some large boulders of brown 

and white quartzite, probably Precambrian.

TUFF UNIT

The tuff unit of the Salt Lake formation was formerly 

the West Spring formation of Williams (in Smith, 

1953) and later was placed in the lower part of the Cache 

Valley formation of Adamson, Hardy, and Williams 

(1955). In the report area it is restricted to Hyrum 

Bench and consists mostly of soft earthy-gray tuff that 

weathers to smooth drab-gray slopes. It also contains 

a minor amount of pebble conglomerate. It is estimated 

to be about 1,200 feet thick on the ridge north of West 

Fork and is overlain unconformably by the upper conglomerate and sandstone unit.

At the base of the tuff unit are two distinctive limestone beds. The lower one is buff, pinkish buff, or white 

compact commonly siliceous fresh-water limestone, 

about 10 feet thick and unconformable either on Paleozoic rocks or on the red Wasatch formation (p. 133). 

The upper is a 1- to 2-foot bed of gray stromatolitic 

limestone that is separated from the lower limestone by 

a few feet of tuffaceous sandstone. Small patches of 

these limestones west of the main body of the tuff unit 

are scattered over the Paleozoic rocks in Hyrum Bench, 

particularly in sees. 25 and 36, T. 10 N., R. 1 W.; and 

suggest that this unit once covered a much larger area.

UPPER CONGLOMERATE AND SANDSTONE UNIT

Overlying the tuff unit on Hyrum Bench is a succession of pebble conglomerate and tuffaceous sandstone 

beds that probably belong in the upper part of the Salt 

Lake formation. This succession is broken by the 

Willow Grove fault so that its total thickness cannot be 

measured, but it is estimated to be 1,000 to 2,000 feet. 

This unit is herein referred to as the upper conglomerate and sandstone unit of the Salt Lake formation. It 

is believed to be equivalent in age to the beds that were 

first included in the Cache Valley formation (Williams, 

in Smith, 1953), and later limited to the upper part of 

this formation (Adamson and others, 1955).

It is not possible to trace the upper conglomerate and 

sandstone unit by continuous exposures from Hyrum 

Bench either northward or eastward. Even the conglomerate in Paradise Bench is separated by younger 

deposits for a distance of nearly 2 miles. There is some 

fossil evidence, however, to support the theory that the 

rocks on Newton and Bergeson Hills on the west side of 

the valley, as well as those near Richmond and Paradise 

on the east side, are correlative with the upper conglomerate and sandstone exposed on Hyrum Bench. Plants 

collected on the east side of Hyrum Bench near the 

Little Bear River in SEty sec. 20, T. 10 N., R. 1 E., are 

thought by Roland W. Brown (1949) to be late Pliocene 

in age. Yen (1947) studied a molluscan fauna containing 3 species of pelecypods and 17 of gastropods, from 

the Junction Hills directly west of Newton, in sec. 15, 

T. 13 N., R. 2 W., 3 miles beyond the west boundary of 

this map, and concluded that it was of Pliocene age, 

probably late Pliocene. Swain (1947) studied ostracodes (12 species, of which 11 were new) from the same 

locality, and, although not able to determine the age 

from the ostracodes, he pointed out the modern character of the fauna and the close resemblance of most of 

the species to modern forms.

The sedimentary materials in the conglomerate and 

sandstone unit are clearly of local origin and are confined to the valley and to the low passes that lead to 

adjacent valleys. These deposits, therefore, are younger 

than the valley and accumulated within it.

The unit contains a wide variety of rock types, both 

fluviatile and lacustrine. Four fairly distinct facies are 

present, which are locally differentiated on the geologic 

map.

A f anglomerate f acies, presumably deposited as alluvial fans, occurs along the east side of the valley from 

the Idaho line to the mouth of Green Canyon northeast 

of Logan. It underlies gently sloping ridges that are 

remnants of a pediment developed on the weak Tertiary 

rocks and extending as far as 3 miles into the valley 

from the mountain front. The ridges weather to smooth 

surfaces mantled with residual fragments from the 

underlying fanglomerate. The fanglomerate typically 

consists of angular to subrounded pebbles and cobbles 

of limestone and dolomite cemented by calcium carbonate. There is little or no interstitial fine clastic material. 

The size of the fragments increases upslope, and large 

boulders are common near the mountain front. No 

fossils were found.
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 135

A conglomerate facies, characterized by rounded 

fragments, is widely exposed in the south end of Cache 

Valley, on both sides of the Little Bear River, and 

locally on the south end of Newton Hill and on Bergeson Hill. It generally consists of rounded pebbles and 

cobbles in a matrix of calcium carbonate and tuffaceous 

sand. The pebbles and cobbles are chert, sandstone, 

calcareous sandstone, and limestone, mostly from Carboniferous formations. West of the area mapped, in 

the Junction Hills, the conglomerate grades into calcareous oolite. In Bergeson Hill it is interbedded with 

tuff and tuffaceous sandstone. In the hills at the south 

end of Cache Valley it is interbedded with oolite, 

tuffaceous sandstone, tuffaceous marl, and a few beds of 

compact limestone.

On West Fork a conspicuous conglomerate marks the 

base of the upper conglomerate and sandstone unit. It 

contains cobbles of purple, brown, and buff Precambrian 

quartzite, also cobbles from the Carboniferous formations of the area, and cobbles of stromatolitic and compact limestone from the underlying tuff unit of the Salt 

Lake, indicating lack of conformity between the two 

units.

On the west side of the valley from the Idaho line to 

the south tip of Newton Hill the rocks of the upper 

conglomerate and sandstone unit are largely thinbedded tuff and tuffaceous sandstone interlayered with 

a few beds of conglomerate and compact limestone, 

which are differentiated as the tuff and tuffaceous sandstone facies. On the southeast slopes of Bergeson Hill 

the tuff has been silicified into a chertlike rock. This 

facies crops out' locally southward; in a quarry west of 

Newton, thick-bedded tuff is interbedded with calcareous oolite; in the south end of Cache Valley conglomerate predominates, but along the Little Bear Eiver west 

of Paradise are several outcrops of calcareous tuffaceous 

sandstone, tuffaceous marl, and compact limestone, 

bearing ostracodes, imprints of grass roots, and many 

impressions of a small clam. Remains of fishes, 

terrestrial plants, and, insects have been found in SE^ 

sec. 20, T. 10 N., R. 1 E.

The upper conglomerate and sandstone unit also includes massive beds of oolitic limestone differentiated 

as the oolitic limestone facies at several localities: the 

north end of Cache Butte; a small isolated hill in sec. 

19, T. 12 N., R. 1 W., 2 miles south of the butte; and 

south and west of Hyrum Reservoir. The oolitic limestone is porous, with no fine interstitial material and 

little cement. Commonly it contains many small snail 

and clam shells, which weather out on exposure, leaving 

molds. In Junction Hills (west of the area mapped) 

the oolite intergrades with conglomerate; in the south 

end of Cache Valley, thinner beds of oolite are inter634448 O—62———2

layered with sandstone and conglomerate; in the quarry 

west of Newton massive beds of oolite are interbedded 

with thick beds of tuff and tuffaceous sandstone.

QUATERNARY DEPOSITS

In southern Cache Valley the exposed Quaternary 

deposits are predominantly sediments of Lake Bonnevine and younger alluvium. Fan gravel and landslides 

of pre-Lake Bonneville age are locally exposed at the 

margins of the basin. Well logs indicate at least several 

hundred feet of fluviatile and lacustrine sediments in 

the subsurface of the basin interior, overlying the Salt 

Lake formation and underlying the Lake Bonneville 

group, which are mainly or entirely of Quaternary age.

PRE-LAKE BONNEVIXiUE DEPOSITS

FAN GRAVEL

In the foothills along the east side of the valley between Blacksmith Fork and Green canyons, the gently 

sloping surface beneath the embankments and deltas of 

Lake Bonneville is interpreted as a piedmont of coarse 

alluvium, that is, a series of coalesced alluvial fans deposited at the mouths of the numerous gullies along the 

mountain front. The only exposure that shows this 

material to appreciable depth is along the lower road at 

the mouth of Logan Canyon, in the gravel pit directly 

across the road from the college hydroelectric plant, in 

the NW!/4 sec. 36, T. 12 N., R. 1 E. Here a few feet of 

coarse, angular, and poorly sorted alluvium crop out 

beneath well-sorted nearly horizontal beds of sand and 

gravel of the Lake Bonneville group. The alluvium 

contains much silt and clay and was deposited by muddy 

water. It includes a block of Paleozoic limestone several 

feet in diameter. Similar material is exposed along a 

canal bank for several hundred feet to the west. These 

exposures probably are representative of the pre-Lake 

Bonneville fan gravel to the north and south in this 

area. Elsewhere, the fan surfaces are rather steeply 

sloping (3°-6°) and are characterized by large angular 

blocks, largely buried and surrounded by finer angular 

alluvium.

CONCEALED DEPOSITS

Logs of a few wells give limited information on the 

buried pre-Bonneville deposits of Quaternary age overlying the Salt Lake formation (figs. 39, 43^7). The 

contact of these sediments with the Lake Bonneville 

group is irregular and lies from 60 to 160 feet below the 

present ground surface. Few wells have gone entirely 

through the pre-Bonneville beds, but several have penetrated 75 to 130 feet of them without reaching the basal 

contact. One well (B3, fig. 39) which was sunk deep 

into the Salt Lake formation logged about 250 feet of
136 LAKE BONNEVILLE

FEET 

5200-,

5000-

4400-

4200-

4000-

3800-

3600-

3200-1

Level of Bonneville shoreline

PALEOZOIC

SALT FORMATION

4 MILES

DATUM IS MEAN SEA LEVEL

EXPLANATION

PALEOZOIC

Peat and muck Clay and silt Gravel

Well-bedded gravel, sand, and silt 

in deltas and shore embankments

Sand and silt

Location of wells shown on piezometric 

map

FIGURE 39.—Diagrammatic cross section of Cache Valley from Cache Butte through Amalga to Smithfleld.

pre-Bonneville deposits of Quaternary (?) age. Both LANDSLIDES

lacustrine and fluviatile sediments are represented in the Several landslides older than Lake Bonneville are

logs. Most prominent are comparatively thick clay exposed around the edges of the valley especially along

zones that may have been laid down in earlier deep the steep east flank of Wellsville Mountain. Most inlakes. Interbedded with these are gravelly and sandy volve weak rocks of the Salt Lake formation, but one

zones that probably are either alluvial or deltaic is composed of calcareous sandstone of the Wells

deposits. formation.
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 137

One of the larger slides is situated on the east side 

of Newton Hill. This slide is about 1 mile long and 

is composed of tuffaceous sandstone of the Salt Lake 

formation. Its pre-Lake Bonneville age is shown by the 

Bonneville and other shorelines carved on its upper part 

and by the lake-bottom sediments which cover all of 

its lower part, except a few low hills at its toe.

A similar but smaller slide from the west side of 

the hill serves as an abutment for the Newton Dam in 

sec. 5, T. 13 N., R. 1 W. Northwest of Avon, along the 

east side of Hyrum Bench, is another landslide which 

is more than a mile wide. The Bonneville shoreline is 

carved on its lower part, showing that this slide antedates this lake level. Similar but smaller slides occur 

north of the main slide.

LAKE BONNEVILLE GROUP

ALPINE AND BONNEVILLE FORMATIONS, UNDIFFERENTIATED

Hunt (1953, p. 17) proposed the name Alpine formation for the oldest deposits of Lake Bonneville, exposed 

below the Bonneville shoreline and mainly above the 

Provo shoreline, and he proposed the name Bonneville 

formation (op. cit., p. 20) for somewhat younger deposits laid down while the lake stood at its highest level, 

marked by the Bonneville shoreline. The Alpine formation consists of lacustrine gravel, sand, silt, and clay; 

but the Bonneville formation is mostly gravel. The 

Alpine probably extends to an altitude of about 5,100 

feet in southern Cache Valley, and the Bonneville about 

35 feet higher, to the Bonneville shoreline, about 5,135 

feet. Exposures generally are too poor in southern 

Cache Valley to show details of stratification and evidence of unconformity between the two formations, 

such as Hunt (1953) andBissell (1962) have inferred in 

Utah Valley. In some areas the highest level deposits 

thought to be Alpine are silty, whereas the Bonneville 

formation is mostly gravel. Although the silt could be 

interpreted as Alpine formation and the gravel as Bonneville, there is uncertainty whether some of the silt is 

a silty f acies of the Bonneville, and some of the gravel 

a gravel facies of the Alpine. In this report, therefore, I have not separated the two formations, except 

for a local selvage of gravel of the Bonneville formation along the Bonneville shoreline.

GRAVEL

Lake gravel of the Alpine and Bonneville formations 

occurs in small local and discontinuous patches along 

both the eastern and western sides of the basin, mainly 

as constructional shore-terrace embankments. On the 

eastern side the gravel embankments overlie embankments of lake silt, but on the western side the silt generally is absent (fig. 40).

The embankments in the southwest corner of the 

valley consist of coarse gravel, derived from coarse 

resistant detritus from Tertiary conglomerate exposed 

on the piedmont west of Wellsville, from the Wells 

sandstone exposed from Wellsville to Sardine Canyon, 

and from Pine and Brushy Canyons, whose upper 

reaches held valley glaciers. Boulders and cobbles of 

blue-gray limestone from the Brazer limestone and buff - 

weathering calcareous sandstone from the Wells formation were washed from these canyons onto the piedmont 

and thence transported by waves southward into the 

embankments. Part of the debris from the canyons may 

have been deposited on the piedmont as terminal 

moraines; but if so, the moraines have been completely 

removed or reworked by wave action. These embankments of coarse gravel are undissected, in marked contrast to the embankments of fine-grained sediments. A 

series of embankments at the mouth of Wellsville Canyon includes several that sweep away from the shore and 

then recurve to meet it, thereby enclosing a depression 

between embankment and shore. Here, as at Reservoir 

Butte, in the western part of Lake Bonneville (Gilbert, 

1890, p. 110), the embankments appear to have been 

built as the lake rose.

Eighteen feet of embankment gravel are exposed in a 

pit on the north side of Newton Hill, SE14 sec. 33, T. 

14 N., R. 1 W. Most of the gravel is in layers averaging 

a few inches thick and extending completely across the 

top of the embankment; but a few layers are two to three 

times the average thickness. Only the thicker layers 

are crossbedded, which also suggests that the embankments were built while the lake level was steadily rising.

Deltaic gravel was deposited at or near the mouths of 

the larger canyons on the eastern side of the valley. 

The mouths of most of these canyons were graded below 

the higher lake levels, and they were drowned for some 

distance upstream when the lake stood at these levels, 

causing deltaic deposition to be largely confined within 

the canyons. These intracanyon deltas subsequently 

have been eroded, except for local remnants. Examples 

of such deltas are those of Smithfield and High Creeks 

(the Smithfield Creek delta contains an unusually large 

amount of silt). No deltaic deposits remain in the 

canyons of the Logan River and Blacksmith Fork, but 

unusually thick shore-terrace embankments of gravel 

bordering the mouths of these canyons suggest that their 

deltas reached the edge of Cache Valley. Deltas were 

built into Cache Valley where the canyon mouths were 

graded to the higher shorelines, notably at the mouths 

of Millville and Providence Canyons. Such deltas are 

asymmetric, lying mostly south of the canyon mouths, 

attesting to southward-flowing longshore currents. At 

Green Canyon (north of Logan) the gravel was entirely
138 LAKE BONNEVILLE

FIGURE 40.—Embankments of gravel of the Alpine and Bonneville formations. Oblique aerial view to northwest from Wellsville; Wellsville 

Mountain at left. Qab, Alpine and Bonneville formations, undifferentiated; Qbb, Bonneville formation; Qpb, Provo formation; Qlm, 

landslide ; Qlw, post-Lake Bonneville slope wash. Photograph by Bert Alien.

transported into shore embankments and no delta was 

formed.

The gravel mapped as Bonneville formation along 

the Bonneville shoreline is thin and discontinuous. The 

thickest deposits are bars of coarse and rather angular 

gravel, formed at the ends of wave-cut terraces where 

the shoreline extends from a ridge or headland across a 

small canyon or bay. Where the bay was deep, an

epaulet-shaped bar was formed on the side of the ravine; 

where the bay was shallow, a crescentic bar was built 

completely across the mouth of the bay.

The only delta at the Bonneville level is at the mouth 

of Providen«3e Canyon, which now has a perennial 

stream. The large gravel embankments at the Bonneville level on both sides of Pine Canyon, west of Wellsville (fig. 40), reflect the large amount of debris that
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 139

moved down this canyon, much of it perhaps glacial outwash. Strong shore currents moved the debris laterally 

into the embankments and no delta was formed.

Gravel referred to the Alpine and Bonneville formations crops out locally in small hills that project above 

lowland benches mantled by lake-bottom silt and clay 

of the Provo formation; the gravel appears to stratigraphically underlie the Provo. In a hill north of 

Mendon, in sec. 5, T. 11 N., R. 1 W., the lake gravel 

largely mantles a buried hill of conglomerate of the 

Salt Lake formation and appears to have been derived 

by wave erosion of the bedrock. On the eastern side of 

the valley are three occurrences: in North Logan at 

Greenville (sees. 22 and 23, T. 12 N., R. 1 E.); north of

Smithfield, in sec. 21, T. 13 N., R. 1 E.; and south of 

Providence, on the line between sees. 10 and 15, T. 11 

N., R. 1 E. In all these occurrences the gravel is well 

sorted, crossbedded, and comparable in lithology, fragment size, and degree of sorting to the gravel in nearby 

deltas of Provo age.

SLLT AND FINE SAND

Current-built embankments of buff silt and fine sand 

are the outstanding feature of Lake Bonneville deposits 

at levels between the Provo and Bonneville shorelines 

(fig. 41). The deposits may have been derived from 

erosion of the pre-Wisconsin soil that presumably 

thickly mantled the hills and valley before Lake BonneFIGCRE 41.—Eroded embankment of silt and fine sand of the Alpine and Bonneville formations. Oblique aerial view southeast from 1 mile 

southeast of Hyrum showing Provo delta of Blacksmith Fork and Little Bear River in foreground. Photograph by Bert Alien.
140 LAKE BONNEVILLE

ville time (Hunt and Sokoloff, 1950). The embankments extend almost continuously along the east side of 

the valley and are well developed along the west side 

from Cornish to Mendon. Here they provide patches 

of arable land, in the midst of rocky or stony ground 

that was formed by the older and underlying rocks. 

These embankments have been severely dissected by 

closely spaced generally parallel gullies consequent upon 

the soft and only moderately permeable silts, forming a 

subdued "badland" topography. At many localities, 

particularly along the east side of the valley, embankments that once were continuous for miles when first 

uncovered by the shrinking lake are now represented by 

scattered low mounds and parallel ridges (transverse to 

the valley side), as a result of being cut by streams from 

the mountains.

The wide embankment in sec. 15, T. 10 N., R. 1 E. 

(fig. 41) appears to preserve its original configuration 

on the interstream ridges, except at their upper ends 

where the silt has been removed. This embankment 

is half a mile wide, 30 feet thick, and lies upon a pediment sloping 10°. Other embankments, such as those 

between Logan and Providence, thicken valley ward and 

end in steep slopes, which may approximate the original 

shape of their lakeward edges.

Stratification in the silt embankments does not 

parallel the underlying surface, but is for the most part 

horizontal. Presumably the constituent sediments were 

moved into place by traction rather than in suspension, 

a conclusion also indicated by the occurrence of the 

sediments in distinct embankments or terraces at the 

shore. Embankments of uniform height around the 

valley sides presumably indicate deposition during 

steadily rising water level. In places the silt also appears to lie upon lake gravel of the Alpine and Bonneville formations, a relationship that further suggests 

overlap by a rising lake. This kind of an overlap is 

exposed in sees. 27 and 33, T. 11 N., R. 1 E., northwest of 

Wellsville and northeast of Paradise in sees. 22 and 27, 

T. 10 N., R. 1 E. Also, on High Creek, in sec. 7, T. 14 

N., R. 2 E., silt overlies deltaic gravel.

The preponderance of silt and fine sand in the embankments can be explained in two ways:

1. Where the lake transgressed foothill slopes of soft 

and deeply weathered rocks of the Salt Lake formation, 

waves stirred up much silt and fine sand, which was 

transported by shore currents onto the embankments. 

This seems to have been the source for the embankments 

between the major canyons of the east side of the valley 

north of Green Canyon, on Hyrum Bench south of 

Hyrum Reservoir, and on Junction Hills (west of the 

mapped area) and Bergeson Hill.

2. In the principal tributary streams, slack water extended far up the canyons and most of the gravel was 

deposited there; only fine-grained detritus was transported to the open lake to contribute to the embankments being built by the shore drift. The extensive 

embankments between Green Canyon and Paradise on 

the east side of the valley probably were derived in this 

manner.

FROVO FORMATION

Hunt (1953, p. 21) defined the Provo formation in 

northern Utah Valley as the deposits that were laid 

down while Lake Bonneville stood at what Gilbert 

(1890, p. 126-134) called the Provo stage. This usage 

is followed in this report.

The Provo is the most extensively exposed formation 

in the Lake Bonneville group in Cache Valley. It is 

subdivided into two members, the gravel and sand member and the silt and clay member, which are intertonguing and intergrading lithof acies units of virtually 

similar age.

GRAVEL AND SAND MEMBER

The gravel and sand member makes up numerous 

deltas, bars, and spits; the largest of such features are 

in the valley. The deltas are the most important shore 

deposits of Lake Bonneville, in bulk as well as in area. 

They cover nearly 15 square miles in the mapped area 

and reach a maximum thickness of about 70 feet. Most 

of their sediment was deposited while the lake stood at 

the Provo level; minor increments were deposited when 

the lake receded from this level. Each of the principal 

streams entering the east side of the valley formed a 

large delta of the Provo formation, and several of these 

deltas coalesced with adj acent ones. The delta of Blacksmith Fork coalesced with those of Little Bear River 

and Millville Canyon, the delta of Logan River merged 

with the small delta of Green Canyon, and the deltas of 

High and Cherry Creeks also joined. On several deltas, 

coeval fan gravel intergrades with the lacustrine gravel 

and sand and is mapped with the gravel and sand member of the Provo formation. The fan gravel locally 

extends considerably above the Provo shoreline—clear 

up to the Bonneville shoreline on the composite delta 

and fan below Providence Canyon.

The smaller deltas are composed entirely of gravel; 

but the larger ones of Logan River, Blacksmith Fork, 

and Little Bear River contain considerable amounts of 

sand and silt. A road cut of the Logan River delta at 

Logan, where Sixth East Street descends toward Logan 

River, exposes 20 feet of laminated silt and fine sand. 

Eastward from this locality along a canal and westward 

in other road cuts the same fine-grained sediments are
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 141

exposed for nearly a mile. Two wide patches of sand 

on the delta at Logan contain no pebbles. There are 

similar but less extensive exposures on the south side of 

the river.

The deltas of Blacksmith Fork, sec. 34, T. 11 N., R. 

1 E., and of Little Bear River at Hyrum Reservoir, 

sec. 8, T. 11 N., R. 1 E., also contain fine-grained sediments. Three large patches of sand on the surface of 

the Blacksmith Fork delta contain no pebbles.

The largest bar of gravel and sand of the Provo formation crosses the south end of the valley from the dam

at Hyrum Reservoir to the Pisgah Hills at the mouth 

of Wellsville Canyon, a distance of 3% miles (fig. 

42). The bar attains a maximum width of 1 mile near 

its east end. It is called the Sterling bar, from Sterling 

Bench, a farming area on its west half, and is composed of sand and fine gravel swept westward from the 

edge of the Provo delta of Blacksmith Fork. Behind 

and south of the bar are two shallow depressions floored 

with Recent slope wash and silt.

A spit of the gravel and sand member extends southward from Cherry Creek in sec. 23, T. 14 N., R. 1 E.,

FIGURE 42.—.Sterling bar of gravel and sand of the Provo formation. In upper left are eroded embankments of silt and fine sand of the 

Alpine and Bonneville formations. Oblique aerial view is to southwest from Hyrum Reservoir. Photograph by Bert Alien.
142 LAKE BONNEVILLE

and another spit of this member, nearly 1 mile long and 

100 feet thick, extends southward from the edge of the 

piedmont west of Wellsville. The gravel appears to 

have been derived from the Tertiary conglomerate in the 

piedmont. Several fairly large embankments of similar 

lithology flank Newton Hill at the Provo and lower 

levels. The gravel came from conglomerate of the Salt 

Lake formation.

SFLT AND OLAY MEMBER

The silt and clay member of the Provo formation 

represents sediment that settled from suspension in the 

lake water onto the lake bottom. This member underlies much of the lowlands of Cache Valley, but it is 

rarely exposed to depth, owing to its low position and 

susceptibility to erosion. The best exposures are along 

the low bluffs bordering the flood plains of the Bear 

Eiver and its tributaries. About 20 feet of the member 

is exposed in bluffs along the river northwest of Cache 

Junction, in NW^4 sec. 30, T. 13 N., E. 1 W. About 10 

feet of the member is exposed west of Richmond on the 

north side of State Highway 170, where it rises through 

the bluffs west of Cub Eiver, near the west boundary of 

sec. 28, T. 14 N., E. 1 E. About 15 feet is exposed in 

a deep gully north of Smithfield, along the lane that 

follows the north boundary of sec. 16, T. 13 N., E. 1 E.

Table 3 shows mechanical analyses of composite samples of the sediment from these localities, over the 

intervals indicated. A bottom withdrawal tube was 

used to make the particle-size separations. The samples 

are largely silt; 75 to 87 percent of the particles is 

smaller than sand size and only 8 to 15 percent smaller 

than silt size.

TABLE 3.—Particle-size composition of silt and clay member of 

Provo formation

Particle size (mm)

0.1250____ _________

.0625.. __ ________

.0442_____________

.0312_____________

.0221... __________

.0156----_________

.011-_____________

.0078__----____--_

.0055____ ___ ____

.0039_____________

North of 

Cache Junction 

(Interval, 3-15 ft)

85.0

75

69

41. 5

26. 5

22. 5

18. 5

14. 5

9. 2

7. 8

West of 

Richmond 

(Interval, 3-9 ft)

100. 0

87

76

47.5

m e

39.5

26. 8

23. 5

16. 5

14.8

North of 

Smithfleld 

(Interval, 3-6 ft)

100.0

83. 8

68. 5

54. 2

41. 3

31. 5

24. 2

18

13. 2

11. 5

NOTE.—Figures in columns 2-4 show the percentage of particles smaller than the 

particle sizes given in column 1.

LANDSLIDES OF LAKE BONNEVILLE AND POST-LAKE 

BONNEVILLE AGE

Several post-Bonneville shoreline landslides are 

mapped along the piedmont between Mendon and Wellsville. The largest is a rockslide, more than a mile long

and a quarter of a mile wide, that extends across the 

piedmont surface from Wellsville Mountain where it 

originated. It is a tongue-shaped mass too rocky to 

farm and still covered with native brush. It resulted 

from undercutting the steep dipslope of the mountain 

face when the lake sto6fl at the Bonneville level.

Smaller landslides involve the ends of gravel embankments at levels between the Bonneville and Provo shorelines. For example, the large embankments of the 

mouths of Brushy and Pine Canyons (fig. 40) were 

built with their distal ends over lake-bottom silt and 

clay. The foundation sediments were unable to support 

the thick piles of gravel, causing the ends of the embankments to collapse into slides. These slides may have 

been active any time after the embankments were built.

POST-LAKE BONNEVILLE DEPOSITS

FAN GRAVEL

Numerous alluvial fans, composed of coarse angular 

poorly sorted fan gravel, have been deposited over the 

Lake Bonneville sediments along the mountain fronts. 

The streams have trenched the deltas and shore embankments of gravel and sand of the Provo formation and 

have redeposited the sediment in fans at lower elevations, over the silt and clay member of the Provo. High, 

Cherry, Smithfield, and Providence Creeks have built 

the largest post-Provo fans, but even these are small 

compared with the deltas of these creeks of Provo age.

FLOOD-PLAIN ALLUVIUM

The modern flood plains are floored with coarse 

gravel to slightly beyond the distal edges of the deltas 

of Provo age; farther downstream gravel becomes increasingly finer and admixed with sand until 4 or 5 miles 

beyond the deltas even the stream channels are sandy 

and largely free of pebbles. The flood plains of the 

Bear Eiver and the lowermost parts of the Cub and 

Little Bear Eivers are underlain mainly by sand and silt, 

some interbedded clay, and perhaps a little gravel 

locally.

ALLUVIAL SAND IN NATURAL LEVEES OF THE BEAR RIVER

No postlake deposit in Cache Valley is as widespread 

or as important economically as the natural levees of 

sand along the Bear Eiver. These levees border the 

channel of the Bear Eiver throughout its course in 

Cache Valley, comprising about 40 square miles of sandy 

well-drained ground that includes some of the best 

agricultural land in the valley. From Trenton southward through Amalga they are y2 to 1 mile wide, near 

Benson Ward they are somewhat wider, and between 

Cornish and Lewiston they border multiple channels 

and have a total maximum width of about 4^ miles.
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 143

The sand probably was derived mainly from the 

Provo delta of Bear River, in northern Cache Valley. 

When the lake level dropped below the Provo shoreline, 

Bear River incised its channel through the delta and 

moved large quantities of the sand onto the lake-bottom 

clay and silts. The earliest sand deposits were covered 

by lake-bottom silt and clay as a result of a minor readvance of the lake, and the channel through the delta 

was partly refilled with sand. After this interruption, 

the process was repeated. The river spread widely to 

the south and east, carrying sand as far as the Cub 

River, and creating the sandy area about Lewiston.

SLOPE WASH

Post-Lake Bonneville slope wash is mapped in two 

areas: At the south end of the valley it floors two closed 

basins behind the Sterling bar (p. 141). The eastern 

basin has received wash from a large area of silt of 

the Alpine and Bonneville formations; the western one, 

from surrounding hills of sandstone of the Wells formation. The other area is along the west side of the valley 

from Newton Hill to the Idaho line. Here the slope 

wash came from thin embankments of the Provo formation on the steep valley side.

EOLIAN SAND

Small patches of eolian sand are mapped north and 

east of Cornish. The sand is reworked from nearby 

sandy post-Lake Bonneville levees of the Bear River 

and forms small dunes.

SPRING TUFA CONES

West of Trenton, in Tps. 13 and 14 N., R. 1W., several 

small low cones of porous limestone have been deposited 

by warm springs that are alined along the face of Newton Hill and north-northwestward for more than a mile. 

This alinement, close to and, parallel with the face of 

Newton Hill, suggests the presence of a fault, which is 

called the Dayton fault zone. The cones are still growing. The outer and older parts of some of the larger 

cones are tilled, but the newer parts commonly are obstacles to cultivation.

INTERPRETATION OF WEIjL LOGS

Numerous water wells have been drilled into the 

Quaternary sediments in southern Cache Valley. Those 

drilled before 1946 are reported by Peterson (1946) in 

a review of the ground-water resources of the valley. 

Records of 16 other wells drilled between 1946 and 1952 

were obtained from the office of the Utah State Engineer. Dr. O. W. Israelsen kindly provided logs of three 

test wells drilled in the Lewiston area as part of a 

drainage study made by him.

The well logs are shown in five cross sections, figures 

43 to 47, whose locations are shown on plate 7. As no 

collar altitudes are available for the wells, the actual 

vertical position of the aquifers and lake-bottom members can only be inferred. Also, the spacing between 

logs is not proportional to the distances between wells; 

hence, the cross sections are largely diagrammatic.

Almost all these logs show an aquifer of sand or 

gravel at a depth between 50 and 100 feet, underlying 

an upper zone of clay and silt. This aquifer is interpreted as an interlake alluvial or deltaic deposit, and 

probably records recession of Lake Bonneville between 

the Provo and an earlier high-lake stage. Thus, the 

clay zone above the aquifer may represent the Provo 

formation, and the clay zone beneath it may belong to 

the Alpine and Bonneville formations.

In the wells southwest of Logan (figs. 46, 47) in the 

area traversed by the Logan River, Blacksmith Fork, 

and Little Bear River, a second distinct aquifer underlies the lower clay zone. This presumably represents 

an interlake episode earlier than Lake Bonneville, and 

perhaps is correlative with the "shallow Pleistocene 

artesian aquifer" of Thomas (1953, p. 83-84) in northern Utah Valley. This deep aquifer is also apparent in 

wells Al and A4 in the Cornish-Lewiston section (fig. 

43) and in three of the wells of the Cache JunctionSmithfield section (fig. 44). It is not so readily distinguished in the wells west of Smithfield (fig. 45), 

where all the sediments are finer and there is less contrast between aquifers and aquicludes.

In several logs of the section from Logan toward 

Wellsville (fig. 47), a thin gravel unit is shown near the 

surface, beneath less than 20 feet of silt and clay. These 

wells are adjacent to the present courses of the rivers of 

the area, and this high gravel may mark a late interlake event when the stream flood plains had slightly 

different boundaries which was followed by a brief 

expansion of the lake.

The well logs indicate that the Quaternary deposits 

in Cache Valley are very thin, suggesting that the valley 

had exterior drainage during most of Quaternary time.

OUTLET OF LAKE BONNEVILLE AT RED ROCK PASS

A brief examination was made of Red Rock Pass, at 

the north end of Cache Valley in Idaho (fig. 38) where 

Lake Bonneville overflowed to the Snake River. The 

pass is across a low east-trending ridge connecting the 

Northern Malad, Range (west of the pass) with the 

Portneuf Range (east of the pass). The ridge consists 

of resistant Paleozoic dolomite, limestone, and shale, 

flanked by conglomerate and tuff of the Salt Lake formation. The highest point in the central part of the 

ridge is at an altitude of 5,560 feet. A pass near the
144 LAKE BONNEVILLE;

Well Al

Sec. 4, 

T.I4N., R.IW.

Well A2

Sec. 6,

T.I4N., R.IE.

Well A3

Sec. 17, 

T.I4N., R.IE.

Well A4

Sec. 10, 

T.I4N., R.IE.

Well A5

Sec. 2,

T. 14 N., R.IE.

FEET

50

100

ISO200-

ALPINE AND 

FORMATIONS

EXPLANATION

Silt and clay

Sand

Gravel

FIGURE 43.—Correlation of lake beds in Cache Valley between Cornish and Lewiston. Wells are located on plates 6 and 7. Altitudes of 

well collars are not accurately known and not the same, but they differ by no more than 20 feet. Spacing between logs not to scale.

east end of the ridge is 5,180 feet in altitude, but it shows 

no evidence of having ever served as an overflow channel. The floor of the pass is at 4,770 feet, virtually the 

Provo level of the lake.

The outlet channel is about 4,300 feet wicle at the 

Bonneville shoreline level where it cuts the Paleozoic 

core of the ridge, but only half that wide at the bottom 

of the pass, that is, at the Provo level. The channel 

is cut in Paleozoic rocks for 2 miles and trends northnorthwest, parallel to the strike of these rocks. These 

rocks dip steeply, as much as 60°, eastward. On the 

west wall is olive-drab shale interbedded with thin limestone layers; on the east side is little shale but much gray 

dolomite (probably the transition zone between the 

Bloomington formation on the west and the Nounan 

limestone on the east). A conspicuous conical hill rises 

from the channel bottom near the west side. It is composed of Tertiary conglomerate, probably the lower
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 145

Well Bl

Sec. 31, 

TI3N., R.IW.

Well B2

Sec. 28, 

TI3N., R.IW.

Well B3

Sec. 25, 

TI3N, R.IW.

Well B4

Sec. 20, 

TI3N., R.IE.

Well B5

Sec. 16, 

TI3N., R.IE.

FEET 

0-1

50-

100-

I 50-

200

EXPLANATION

Silt and clay

Sand

Gravel

PROVO FORMATION

AND BONNEVILLE 

FORMATIONS

Peat and muck

FIGURE 44.—Correlation of lake beds in Cache Valley between Cache Junction and Smithfleld. Wells are located on plates 6 and 7. Altitudes 

of well collars are not accurately known and not the same, but they differ by no more than 50 feet at extremes of section. Spacing 

between logs not to scale.

conglomerate unit of the Salt Lake formation and may 

be either an old cay on fill in the pre-Tertiary surface of 

the ridge, or it may be an inf aulted block.

The highest traces of the channel at the pass are approximately at an altitude of 5,135 feet, the same as the 

nearest marks of the Bonneville shoreline south of the 

pass, and probably the original elevation of the overflow point was near this figure. East of the channel in 

the northeast corner of sec. 32, and in the W^NW^ sec.

29, are several abandoned channels in bedrock that probably represent temporary stands during lowering of the 

outlet.

A large alluvial fan, built by Marsh Creek, heads 

about 3 miles north-northeast of the outlet. Projected 

southward, the gradient of this fan falls well below the 

Bonneville shoreline, and thus the fan played no part 

in controlling the lake overflow, contrary to Gilbert's 

(1890, p. 175-178) interpretation.
146 LAKE BONNEVILLE

Well Cl

Sec. 34, 

T.I4N., R.IE.

Well CZ

Sec. 16,

T.I3N., R.IE.

wen C3

Sec. 29, 

T.I3N., R.IE.

Well C4

Sec. 4, 

T.I2N., R.IE.

FEET

50H

IOOH

5(H

Gravel

FIGURE 45.—Correlation of lake beds in Cache Valley between Richmond and Smithfleld. Wells are located on plates 6 and 7. Altitudes 

of well collars are not accurately known and not the same, but they differ by no more than 25 feet. Spacing between logs not to scale.

STRUCTURAL GEOLOGY

Southern Cache Valley probably is a graben bounded 

by high-angle normal faults similar to those that bound 

other basins of the Basin and Range province. 

Although earlier folding and faulting in the surrounding mountains is assumed, the evolution of the present 

features of the valley apparently began in the middle 

Tertiary and has continued to the present. The major 

faults displace Wasatch and older units and, locally, 

beds of the Salt Lake formation. No displacement of 

the Lake Bonneville group was recognized.

In most of southern Cache Valley the beds of the 

Salt Lake dip moderately to steeply. In some areas,

dips change markedly in direction and magnitude over 

short distances, presumably because of faulting; elsewhere, strikes and dips are fairly uniform for miles. 

Some of the faults of post-Salt Lake time lie basinward 

from the mountain fronts, causing foothill benches of 

Tertiary rock above the general level of the valley floor. 

Only the major faults are mapped. Intermittent or 

fairly continuous faulting and tilting during deposition of the Salt Lake formation is indicated by unconformities between the various units of the group.

On the west side of the valley are the Clarkston and 

Dayton fault zones and the Wellsville and Willow 

Grove faults; along the east side of the valley is the
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 147

Well Dl

Sec.14,

T.IIN, R.IW.

Well D2

Sec.14, 

T.IIN., R IW

Well D3

Sec. 12,

T.IIN, R.IW.

Well D4

Sec. 7,

TUN, R.IE

WellDS

Sec. 5, 

T.IIN, R.IE.

Well D6

Sec. 5, 

T.IIN, R.IE.

Well D7

Sec. 4, 

T.IIN, R.IE.

FEET O-i

50-

100-

150-

200-

250J

Gravel

Sand

FIGUHE 46.—Correlation of lake beds in Cache Valley southwest of Logan. Wells are located on plates 6 and 7. Altitudes of well collars 

are not accurately known and not the same. Altitude along section increases from 4,435 feet at west to about 4,500 feet at east. 

Spacing between logs not to scale.

East Cache Valley fault zone. Only the Willow Grove 

fault is actually exposed in the area mapped; the others 

are concealed by Salt Lake or Quaternary deposits, but 

are inferred from physiographic evidence to lie close to 

the foot of the steep mountain slopes.

The Clarkston fault zone extends from north of 

Cache Junction southward along the base of Cache 

Butte. The fault is inferred from the escarpment at 

Cache Butte, which rises several hundred feet from the 

valley floor and exposes both Paleozoic rocks and oolitic 

limestone and tuff of the Salt Lake formation. The 

Dayton fault zone borders Newton and Bergeson Hills 

on the east and extends far to the north beyond the 

boundary of the map to Eed Rock Pass, the outlet 

of former Lake Bonneville. Kocks of the Salt Lake exposed on the east side of Bergeson Hill and on Newton

Hill are brecciated because of movement in this fault 

zone, although massive beds of oolitic limestone in the 

isolated hill in sec. 19, T. IS? N., R. 1 W., are undeformed. In sees. 28 and 33, T. 14 K, R. 1 W., and sec. 

3, T. 13 N., R. 1 W., small warm springs, marked by 

low tufa cones, are alined at the based of an escarpment 

along the main fault. Several small faults of similar 

trend, but small displacement, appear along Bergeson 

Hill.

The Willow Grove fault extends northward along 

Hyrum Bench, parallel to the inferred fault at the 

eastern margin of Paradise Bench. The beds on the 

east side of the fault appear to have been downdropped 

and rotated until they lie nearly horizontal against 

the moderately dipping beds on the west side. The 

beds west of the fault, in the upper conglomerate and
148 LAKE BONNEVILLE,

FEET 

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FIGURE 47.—Correlation of lake beds in Cache Valley from Logan toward Wellsville. Wells are located on plates 6 and 7. Altitudes of 

well collars are not known and not the same, but they differ less than 100 feet from east (highest) to west ends of line. Spacing 

between logs not to scale.

sandstone unit of the Salt Lake formation are fairly 

regular in attitude from the Hyrum Reservoir south 

into Big Spring Hollow, a distance of 5 miles. Their 

strike averages K 45° W. and their dip 25° to the 

northeast.

ENGINEERING GEOLOGY 

GROUND WATER

Cache Valley is well watered. At least five major 

perennial streams cross the valley, and several smaller 

ones contribute substantially to surface and subsurface 

water supplies. The Lake Bonneville group and preLake Bonneville sediments of Quaternary age constitute the ground-water reservoir of the valley, and the 

underlying much better consolidated and less permeable 

rocks of the Salt Lake form the sides and bottom of

the basin. The ground-water supplies have been reported on by Peterson (1946).

Beneath the central lowlands the water table is within a few feet of the surface throughout the year, and 

in many places is so shallow as to create serious drainage problems. On the deltas and shore embankments 

of the Lake Bonneville group, however, the depth to 

water is locally 100 feet or more. The high water table 

makes shallow wells possible everywhere on the valley 

floor, but such wells are uncommon because of the ease 

of obtaining artesian water that is more potable and 

less likely to be contaminated. Artesian water is obtained from two principal aquifers of gravel and sand 

(p. 136, and figs. 39, 43^7), which are separated 

by relatively impermeable clayey zones. The map (pi. 

7), showing the artesian piezometric surface, probably
GEOLOGY OF SOUTHERN CACHE VALLEY, UTAH 149

represents a composite pressure surface, as many wells 

tap both aquifers. The isopiestic lines show that recharge to the aquifers is by perennial streams where 

they emerge from canyons onto the alluvial fans or lake 

deltas.

East and north of Newton Hill are several warm 

springs marked by low cones of porous tufa (p. 143).

CONSTRUCTION MATERIALS

The delta, bar, and Recent flood-plain deposits in 

Cache Valley are sources of sand and gravel for construction materials. The principal and preferred 

sources for sand and gravel are the deltas of the Provo 

stage that are adjacent to the larger canyons and larger 

towns along the east side of the valley, but gravel shore 

embankments and stream-channel deposits also have 

been utilized; thus, gravel pits are rather evenly and 

widely distributed in the valley.

The largest sand -and gravel operations are near 

Logan. Here the sand is screened from the pebbles and 

cobbles, crushing the latter down to the maximum diameter suitable for concrete aggregate. Both the sand 

and coarse aggregate are washed. At the smaller pits 

elsewhere the demand does not justify crushing or 

washing, and the sand and gravel are merely separated 

by screening without further processing. In sec. 14, T. 

14 N., R. 1E., at Merrills, and in sec. 21, T. 11 N., R. 1E., 

at Nibley, pits have been opened in post-lake stream 

gravel. Between Richmond and Smithfield and also 

east of Paradise are small pits in embankments of 

Alpine and Bonneville sediment. Just west of Wellsville a pit utilizes gravel from the large spit at the 

Provo level (p. 142), but the large embankments of 

gravel of the Alpine and Bonneville formations farther 

from town have not been utilized. Small quantities of 

gravel have been excavated from a pre-Lake Bonneville 

deposit north of Mendon and from three gravel embankments on the south side of Newton Hill, at and 

below the Provo level. On the north end of Newton 

Hill, pits have been opened in embankments of the 

Alpine, Bonneville, and Provo formations; but here 

the gravel is crumbly, for the pebbles and cobbles consist of soft tuff and tuffaceous sandstone of the Salt 

Lake formation.

Much of the gravel has been utilized for road metal. 

Every pit has supplied some gravel, and some pits have 

been operated solely for road-building material. 

Through the years large quantities of gravel have been 

distributed along the roads not only to raise the grades 

and provide better drainage, but also to improve the 

road surfaces. The first pavements of concrete utilized 

large quantities of gravel for aggregate, and: the most 

common form of paving today, a bituminous mix, requires finely crushed stone. Both the gravel and the 

stone have been supplied largely from the gravel deltas 

and embankments of the1 Provo formation.

The crumbly gravel from the west side of the valley 

near Trenton and Cornish, in which the pebbles and 

cobbles are composed of soft tuff and tuffaceous sandstone, provides a satisfactory surface on secondary 

roads. It breaks down to a degree just sufficient to make 

a desirably smooth surface on little-traveled lanes and 

farm-access roads.

The lake-bottom sediments on the floor of Cache 

Valley include a large quantity of clay suitable for the 

manufacture of bricks, but only one brick kiln, in the 

northwestern part of Smithfield, has been operated in 

the valley. Here, to 1957, most of one city block has 

been excavated to a depth of about 15 feet. During the 

present building boom (1957) much brick used in Cache 

Valley is being brought from larger plants at Ogden 

and Salt Lake City. Clay that appears identical with 

that at Smithfield extends northward for 6 miles in a 

belt 2 miles wide, and this area represents but a small 

part of the clay underlying the whole valley floor.

ENGINEERING APPLICATIONS

In Cache Valley at least 35 percent of the farmland 

lies below irrigation canals, and about 75 percent of the 

total crop value is produced from irrigated land. 

Water is obtained from every perennial stream entering the valley; but Bear, Little Bear, Logan, and Blacksmith Fork Rivers furnish most of the supply, particularly late in the growing season. The canals cross all 

the geologic formations in the valley, and their seepage losses range widely, from negligible to as high as 

50 percent of the total flow in a distance of 1,800 feet. 

Generally speaking, seepage losses are high to moderate 

on the deltas and lake embankments of gravel and sand, 

gravel flood plains, and alluvial fans, and sandy natural 

levees of the Bear River; they are moderate to low on 

pediments and foothill slopes on the Wasatch and Salt 

Lake formations; and low to negligible on the embankments of silt and fine sand of the Alpine and 

Bonneville formations and on silt and clay of the 

Provo formation in the valley bottom. Improved efficiency in maintenance and improvement of the agricultural lands require the elimination, as far as practicable, of seepage losses by lining the canals where they 

cross permeable deposits. The best natural material 

in the valley for lining canals is clay of the Provo 

formation, and it is available throughout the valley 

within a mile or two of where it will be required.

Three types of areas require drainage to be productive cropland. Most of the poorly drained areas occur 

where silt and clay emerge from beneath more per-
150 LAKE BONNEVILLE,

meable deposits of gravel and sand in shore embankments, deltas, or alluvial fans. Water, infiltrating the 

gravel, travels downward to the water table perched 

on the clay, then percolates valleyward to seep out at 

the toe of the gravel deposit and saturate a strip of land 

below. Irrigation on the gravel deltas, fans, and embankments increases the discharge of the seeps. The 

largest of these seep areas are on the east side of the 

valley, below the large deltas and fans. On the west 

side of the valley, however, from Trenton to the Idaho 

line, is an almost continuous line of seeps, along the 

contact of gravelly colluvium and fan gravel overlying 

silt and clay of the Provo formation. Seep areas of this 

type can be corrected or ameliorated by reducing canal 

seepage losses from canals crossing the overlying gravel 

deposits, by reducing irrigation of these areas, and 

by constructing drainage canals just downslope from 

the contact of the gravel and underlying clay.

The sandy natural levees along the Bear River comprise about 40 square miles of excellent cropland in the 

north end of the valley. Water seeping from Bear 

River, from irrigation canals, and from irrigated fields, 

sinks rapidly to the base of the sand where it forms a 

water table perched on the underlying clay, and then 

emerges at the outer edge of the sand deposit. Over 

the thinner outer parts of the levees farming is possible only where open or subsurface drains have been 

constructed.

An area northwest of Logan, between U.S. Highway 

91 and the Logan-Cache airport, is waterlogged by 

artesian water moving upward from a gravel aquifer 

about 40 feet below the ground surface (Israelsen and 

McLaughlin, 1935).

Two small earthfill dams have been constructed by 

the U.S. Bureau of Reclamation, one near Hyrum in 

sec. 7, T. 10 N., R. 1 E., the other near Newton in sec. 5, 

T. 13 N., R. 1W. The dam near Hyrum is 500 feet long, 

90 feet high, and impounds the Little Bear River. The 

stream's course at this point is along the contact between 

deltaic gravel of the Provo and Salt Lake formations. 

Fill for the dam consisted of silt and fine sand, with 

some small pebbles, from a Provo level bar half a mile 

west of the damsite. Blocks of massive oolitic limestone, from a bedrock hill half a mile south of the damsite, were used for facing the dam.

The dam near Newton is on the west side of Newton 

Hill, which is underlain by thin-bedded tuff aceous sandstone of the Salt Lake formation. The abutment of the 

dam is in a pre-Lake Bonneville landslide composed of 

this sandstone, and fill for the dam was obtained from 

the slide mass. The dam is faced with blocks of oolitic 

limestone from an outcrop of the Salt Lake formation 

2 miles west of the town of Newton. Gravel from the

large bars of the Alpine and Bonneville formations just 

north of the dam were unsuitable for concrete aggregate 

because they contain too much soft tuffaceous sandstone.

REFERENCES CITED

Adamson, R. D., Hardy, C. T., and Williams, J. S., 1955, Tertiary

rocks of Cache Valley, Utah and Idaho, in Utah Geol. Soc.

Guidebook 10, p. 1-22. 

Bissell, H. J., 1962, Lake Bonneville—Geology of southern Utah

Valley, Utah: U.S. Geol. Survey Prof. Paper 257-B, p.

101-130. 

Brown, R. W., 1949, Pliocene plants from Cache Valley, Utah:

Washington Acad. Sci. Jour., v. 39, no. 7, p. 224-229. 

Eardley, A. J., 1944, Geology of the north-central WasatchMountains, Utah: Geol. Soc. America Bull., v. 55, no. 7, p.

819-894. 

Gilbert, G. K., 1890, Lake Bonneville: U.S. Geol. Survey Mon.,

v. 1, 438 p. 

Hayden, F. V., 1869, Preliminary field report of the United

States Geological Survey of Colorado and New Mexico:

U.S. Geol. and Geog. Survey of the Terr. (Hayden),

3d Ann. [Prelim.] Field Rept., 155 p., [rep. 1873, p.

103-261]. 

Hunt, C. B., 1953, in Hunt, C. B., Varnes, H. D., and Thomas,

H. E., 1953, Lake Bonneville—Geology of northern Utah

Valley, Utah: U.S. Geol. Survey Prof. Paper 257-A, p.

11-47. 

Hunt, C. B., and Sokoloff, V. P., 1950, Pre-Wisconsin soil in the

Rocky Mountain region, a progress report: U.S. Geol.

Survey Prof. Paper 221-G, p. 109-123. 

Israelsen, O. W., and McLaughlin, W. W., 1935, Drainage of

land overlying an artesian ground water reservoir: Utah

Agr. Expt. Sta. Bull. 259. 

Mansfield, G. R., 1920, The Wasatch and Salt Lake formations of

southeastern Idaho: Am. Jour. Sci., 4th ser., v. 49, p.

399-406. 

———1927, Geography, geology, and mineral resources of part

of southeastern Idaho: U.S. Geol. Survey Prof. Paper 152,

409 p.

Peale, A. C., 1879, Report on the geology of the Green River district [Wyo.]: U.S. Geol. Geog. Survey Terr. (Hayden)

Ann. Rept. 11, p. 509-646. 

Peterson, W., 1946, Ground water supply in Cache Valley, Utah,

available for domestic use and irrigation: Utah State Agr.

College Ext. Service, N.S. 133. 

Slentz, L. W., 1955, Salt Lake group in lower Jordan Valley,

Utah, in Utah Geol. Soc. Guidebook 10, p. 23-36. 

Smith, N. J., 1953, Tertiary stratigraphy of northern Utah and

southeastern Idaho, in Inter-mountain Assoc. Petroleum

Geologists, 4th Ann. Field Conf., p. 73-77. 

Swain, F. M., 1947, Tertiary non-marine Ostracoda from the

Salt Lake formation, northern Utah: Jour. Paleontology,

v. 21, no. 6, p. 518-528. 

Thomas, H. E., 1953, Water resources, in Hunt, C. B., Varnes,

H. D., and Thomas, H. E., 1953, Lake Bonneville—Geology

of northern Utah Valley, Utah: U.S. Geol. Survey Prof.

Paper 257-A, p. 60-92. 

Williams, J. S., 1948, Geology of the Paleozoic rocks, Logan

quadrangle, Utah: Geol. Soc. America Bull., v. 59, no. 11,

p. 1121-1163. 

Yen, Teng-Chien, 1947, Pliocene fresh-water mollusks from

northern Utah: Jour. Paleontology, v. 21, no. 3, p. 268-277.
INDEX

Page

Alluvial fan, Marsh Creek____________________________ 145 

Alluvial fans.——.__—————————————————— 134,135,142,149,150

Alluvial sand, in natural levees of the Bear River_______________ 142-143 

Alluvium, flood-plain_______-___—__—._—_——_______ 142 

Alpine formation______________________________ 137,143,149,150 

Amalga...__________________-___--__——————-____ 142

Analyses, mechanical, composite samples of silt and clay member of Provo

formation___________.___--__—_-___—____ 142 

Artesian water.___________-__—__--__——...__——_. 148,150 

Avon___________________________________________ 137

Bear Lake Valley..——._-__.-__————.—..___.——___- 133

Bear River, alluvial sand in natural levees..__________________ 142-143 

natural levees of alluvial sand____________________ 142-143,149,150 

Provo delta..._._———..._———————— ———_..._..... 143

Benson Ward....___________________________________ 142

Bergeson Hill.........._._.....—_...——.—....._.......... 134,135,140,147

Big Spring Hollow— -_——....„——_————————_.......... 133,148

Blacksmith Fork.— „_—————————.——————— 137,139,143,149

Blacksmith Fork canyon.______________________________ 135 

Blacksmith Fork delta....._........___._____.__._......__ 140,141

Bloomington formation__________._____________________ 144 

Bonneville formation.___._.__-______.________ 137,138,143,149,150 

Bonneville shoreline————————————— 137,138,139,140,142,144,145

Brazer limestone__—--------_—.-.—————_——.—_.___.___-._ 137

Brushy Canyon..__________________________________ 137,142

Cache Butte....__.——..———......................_............... 135,147

Cache Junction...___.——.„.——.——.-—...—_._. 142,143,145,147 

Cache Valley formation.._——_—__——.——_—__—————_... 134 

Calcareous oolite...____..__-______—_______________ 135 

Canals, seepage losses___——_—__.-__——_—__--_..—-__- 149,150 

Cherry Creek...—————————————————————- 140,141,142

Clarkston fault zone. —....——_———_—.__--------_______ 146,147

Clay suitable for manufacture of brick______________ -________ 149 

Collinston, Utah--....--___________.__________________ 133

Collinston congolomerate__..___________________________ 133 

Construction materials, sources._.___-.__.__.___..__.__... 149 

Cornish.._____—— ________.____.__________ 140,142,143,144,149 

Cub River————————————————.——_—.._.—.. 142,143

Dams, earthflU--.___-__________-...____.........._-___.. 150

Dayton fault zone..____-___..._________..________ 143,146,147 

Deltas, composition.--------------_-----__-_ ———___..-.------. 140-141

gravel-.-.----.-----------------.--------.--.---.---------------.--- 137,140,150

intracanyon.-------------------_...--__---_----------------_. 137,140

Provo formation.. — ....................................... 139,140-141,143,149

Dip of beds...------.----.-------_-----.,-------.--------------_-----.- 146,147,148

Drainage...........——— — — —.. — - — ..—. — ...-...........- 143,149-159

Dunes, eolian sand.,.---------------_----------------_....----.-----.-... 143

East Cache Valley fault zone-. —._---------__--------_--------------- 147

Embankments of buff silt and fine sand, Alpine and Bonneville formations.-- 139-

140,141,142 

Eolian sand, post-Lake Bonneville------_..__..__-.__.._-------- 143

Fan gravel, post-Lake Bonneville deposit_.- — -— — - — ——— — _..- 142

pre-Lake Bonneville deposit-----___. — -——.- ——-- — _------- 135

Provo formation.-------_------_----_---.-.---_................_------ 140

Farmland, irrigation_-....---.-----....----...-...._------------------- 149-150

Faults, normal-----__----_---.__.___-------_.-_.--.__-------- 146

Fleldwork—... ———— —— ——— — ._ —__— — — — _ ——— __ — — _ 132

Fossil plants—...... —— ........ —................................. — . 134,135

Gravel of Alpine and Bonneville formations.--_-- — .____--__. — — 137-139,150

Gravelpits.—- ————— ——————— —————— ——— __—————— 135,149

Green Canyon.-..---------------.-----..--.....--................. 134,135,137,140

Greenville__..........._____..____.__........._.-____...- 139

Ground-water reservoir of Cache Valley._-.__.__.._._---_-_-.__-. 147 

High Creek............................................................. 137,140,142

Page 

Hyrum, dam near._--------_-____-________.__________ 141,150

Hyrum Bench, Utah----.___________..____._______ 134,137,140,147 

Hyrum Reservoir.—_ — _________-______. ________ 140,141,148

Irrigation canals.---__-__---________._______________ 149-150 

Junction Hills._---------_-________________________ 134,135,140

Lake Bonneville--..---------------------.--..-.._......_. 131,135,137,140,143

Lake Bonneville group----.--..-.--...----_..._._...... 135,137,146,148

Landslides, post-Lake Bonneville age__ —.____---___...__... 136,142

pre-Lake Bonneville age____..._..____________... 135,136,137,150

Laramide orogeny.._----------------_....._____._..._..._.. 132

Lewiston...—— — — — —— ------- —— _ ———_____________________ 142,143,144

Little Bear River——-------------------------- 134,135,139,140,141,142,143,149,150

Little Bear River delta----------------------------.----..----—.---. 140,141

Location of Cache Valley.----..---------------------_..-._...__-------- 131

Logan. —— .-..............————————.. ————...... 140,141,143,147,149,150

Logan Canyon.__._.___-__-__....___.___._______ 135

Logan River...———_———————..„.._____———— 137,140,143,148,149 

Logan River delta___________________________________ 140

McMurdie Hollow..—---—-—_.___.______.___.______ 133 

Madison formation__________________________________ 133 

Marsh Creek—. ____________________________________ 145 

Mendon, Utah-......._-.————————————_____ 133,134,139,140,142,149

Merrills...———————..————._..—_.___.......__......__ 149

Millville Canyon._....._—............._......_......_____.... 137,140

Molluscan fauna, Junction Hills———_._„———_.._.____________ 134 

Morgan Valley.--___________________________________ 133

Newton Dam.——.______.__.______________________ 137,150 

Newton Hill——_.... ...... .....__.____.. 133,134,135,137,142,143,147,149,150

North Logan..._______.......___-____________________ 139

Northern Malad Range__—————————-——_.....____________ 143

Nounan limestone_____————————————.—_.„______.____ 144

Ostracodes, Junction Hill__......._______________________ 134

Paleozoic formations in the mountains adjacent to southern Cache Valley__ 132 

Paradise, Utah......._-__.......__....._—————— 133,134,135,140,149

Paradise Bench.___________________________._______ 134,147

Piedmont, between Mendon and Wellsville...__________________ 142

on Salt Lake formation..————————————————————————____ 139

west of Wellsville-______________________________ 142

Pine Canyon._..__———_——__..___—___...... 137,138-139,142

Pisgah Hills———___........_______....__—___.________ 141

Portneuf Range..______———.„...————_———.——.._____ 143 

Providence___________________________________ 139,140 

Providence Canyon....___._..._________...__..._____ 137,138

Providence Canyon delta_____._______________—______ 138

Providence Creek..._________________________________ 142

Provo formation__________________________________ 139,149,150

gravel and sand member.—————————————————————__.__ 140-142

silt and clay member....———.._———.——_..———_____ 14.2,149

Provo shoreline...—..—__..„—.—__....___ 137,138,139,140,142,143,144

Red Rock Pass.____.____________________________ 143-145,147 

Reservoir Butte.______———.._———...._______________ 137 

Richmond—————————____————————————— 134,142,146,149

Salt Lake formation———_——..._————————_... 131-132, 133-135.

136-137,139,140,141,142,143,145,146,147,148,149,150

conglomerate facies.__—————...—_...__.____________ 135 

fanglomerate facies_._————————————_„—......____..___ 134

lower conglomerate unit_______________________ 133-134,144-145 

oolitic facies.-_____________________________ 135,137,147,150 

tuff unit-.__________________-____________--__ 133,134,147 

stromatolitic limestone..-_________________________ 134 

upper conglomerate and sandstone unit..___________-„„.— 133,134-135

151
152 INDEX

Page

Salt Lake group..___________.__—________________ 133 

Salt Lake Valley...——————......————.....—.....————........ 133

Sardine Canyon_________________._______________ 137

Seepage losses from canals..____....__......_——_——___.___ 149,150

Silt and fine sand, Alpine and Bonneville formations...___________ 139-140 

Slope wash, post-Lake Bonneville-...___—-__—___-_______ 143 

Smithfleld.————.————————————... 139,142,143,145,146,149

Smithfield Creek...——.....———————————————————— 137,142

Snake River-_________.________-________________ 143 

Spit of gravel and sand member of Provo formation...____.____ 141-142,149 

Sterling Bar.____...._____._____________________ 141,143

Sterling Bench....______.__________.___.___._____ 141

Thomas, H. E., quoted.—.__________.__.___.___.____ 143 

Topography, badland...._____________________________ 140 

Trenton.________________....________________... 142,149,150

Page 

Water Canyon formation________„___.___„_...__...___ 133

Watertable...——————————————————————.___. 148

Warm-spring tufa cones, post-Lake Bonneville.________..__—. 143,147,149 

Wasatch formation. ———..........................————..... 132-133,146,149

Well logs—_————————————————————— 135-136,144-148; pis. 6,7

interpretation.._——.————————————————————.———— 143; pi. 7 

Wells formation... — ...—————................... ———— 133,134,136,137,143

Wells sandstone...._—————————————————————————————— 137

WeUsville, Utah— ——————————————— 133,134,137,140,142,143,148,149

Wellsville Canyon————————————————————————__ 137,141

Wellsvillefault.—————————————————————————— 146

Wellsville Mountain.——————————————————— 133,134,136,138,142

West Fork————————————————_._—.—————-—. 134,135

West Fork of Big Spring Hollow.———————————————————— 133

West Side Canal, near Wheelon...———....................——...——... 133

West Spring formation..____——_—__——_—————————————— 134 

Willow Grove fault————————————————____—..—— 134,146,147
Lake Bonneville

GEOLOGICAL SURVEY PROFESSIONAL PAPER 257

This professional paper was 

printed as separate chapters A— C

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1962
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEW ART L. UDALL, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director
CONTENTS

[Letters in parentheses designate the separately published chapters]

(A) Lake Bonneville: Geology of northern Utah Valley, Utah, by C. B. Hunt, H. D.

Varnes, and H. E. Thomas _______________________________________________ 1

(B) Lake Bonneville: Geology of southern Utah Valley, Utah, by Harold J. Bissell____ 101

(C) Lake Bonneville: Geology of southern Cache Valley, Utah, by J. Stewart Williams. 131

in

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