DEPARTMENT OF THE INTERIOR

HUBERT WORK, Secretary

UNITED STATES GEOLOGICAL SURVEY

GEORGE Ons SMITH, Director

______ t

Water-Supply Paper 539

GEOLOGY AND GROUND-WATER RESOURCES

OF

TOWNSEND VALLEY, MONTANA

BY

WASHINGTON

1OVBBNMBNT PRINTING OFFICE 

1925
ADDITIONAL COfIE8

Of THIS PBBUCAKOM HAT BB PKOCtJEED FKOH

THE SUPERINTENDENT OF DOCUMENTS

GOVERNMENT PRINTING O?FK3B

WASHINGTON, D. C.

AT 

16 CENTS PER COPY
CONTENTS

Page

Introduction _________________________...._._________ 1

Field work__________________________________ 1

Summary _______,.______________________.__,____ 2

History of settlement. j. 8

Topography ___________ _ _________,_____._____._ 5

Principal features 5

Benches __-__________._.___._________.____._ 6

 : "Valley bottoms_____________________________ 8

Hilly lands_____________________'-____________ $

Drainage ________________.____________-_,_____ 9

Vegetation ____________________________________ 10

Climate _____________________________^_____________ 10

Geology ___ . ____________ _ _ 18

Pre-Tertiary rocks. ______________________________ _ 18

: Stratigraphy _-___i.________-.'.___~________;__».;_ 18

 Structure ________.;_.____._____________'._.__ 15

Tertiary rocks _____ ________~ __.i !____ 17

Literature ... :__ __ 17

' Stratigraphy ______..____.. ___________ ____^1_ 22

Lower series (OHgocene) ;; __u_____j 22

Upper series (Miocene)________-___________ 20

Structure ________________________________ SO

Folds _______________________________ 81

Faults _______________________________ 82

Age and correlation__________________________ 83

Quaternary deposits ____________________________ 84

Bench gravel______________________________ 85

Valley gravel_____________________________ 36

Glacial deposits____________________.________ 87

Physiography __________._______._________.__.____ 88

Mineral deposits_______________________________.^__ 44

Marble ____________________________________ 44

Diatomaceous earth______________________.______ 44

Oil __________________________________________ 45

Coal _____________________________________ 45

Gold ______________________________________ 45

Ground water __________________________________ 46

Water in pre-Terttary rocks 46

Springs ______.___________________________ 46

Wells ___________________________________ 47

Water in Tertiary and Quaternary rocks ___ _ _______ 48

Wells in the bench lands_______________________ 48

Wells in the valley bottoms .___ _ 51

Public water supplies_________________________ 61

in
IV CONTENTS

Ground water Continued.

Water in Tertiary and Quaternary rocks Continued, Page

Springs __________________________________ 52

Water table______,r^r^r^77T^. _ _ 53

Source of ground waterlJ_____.'_!_'_!_______________ 55

Quality ______________-___________________ 56

Artesian water________'._______________________ 58

General conditions___________________________ 58

Local conditions _____ _ _ _ :_ __:_--___; 59

index ____________________________________ J__ '61

ILLUSTKATIONS

v, .. . . . .,->,.- /« , ., /Page 

i»LATE I. A, Bench No. 1; B, Oligocene beds truncated by bench, ^o.^-^i, 8

* II. A, Marble (Cambrian limestone) southwest of Townsen<J;i , s , i

«)j -B, Lake Sewell and Spokane Hills. .__. __~T»-H* -.; 9 

9JIGT7BE J. Index map showing location of Townsend Valley. _ __ , iu .?

n 2. Variations in precipitation at Helena _ _ _,,.,,J3

;;j 3. Geologic map of Townsend Valley _r___,^wr,..r.t.r.i.^ ( . <\ 14

::j 4. Geologic section north of Sixmile Creek. -^,^^if^^^.^^ 16

/.} 5. Geologic section near Canyon Ferry. tvtrl^P^^ 16

;i 6. Diagram showing water levels between Deep -Creek; and ,

;-i Greyson Creek _ ,r^t^_^(,^_ 54

: 7. Diagram showing water table southeast of Warjn Spring

 " Creek ____ _ _____. . M -,...,1,, -___ 55
GEOLOGY AND GROUND-WATER RESOURCES OF 

TOWNSEND VALLEY, MONTANA

By J. T. PARDEE

INTRODUCTION

The area described herein as Townsend Valley is in west central 

Montana southeast of Helena (fig. 1). It includes the widened part 

of the valley of Missouri River between Canjon Ferry and Toston 

and a broad lowland west of Toston drained by Crow Creek and its 

tributary Warm Spring Creek. This part of Missouri Valley trends 

from north to northwest, is about 45 miles long, is 16 miles wide in 

its southern part, and tapers to a point at the northwest. Near its 

south end it is joined on the west by the lowland that lies west of 

Toston, an area about 15 miles long and 10 miles in average width, 

whose longer axis trends north.

Townsend Valley, as described above, is about 60 miles long and 

600 square miles in extent. Most of it is agricultural land, and 

farming land stock raising are the principal industries. Townsend, 

near the center, is the county seat of Broadwater County and the 

principal trading point. Toston, Winston, and Radersburg are 

small towns near the southeastern, northwestern, and southwestern 

limits of the valley respectively. On Missouri River at Canyon 

Ferry, near the north end of the valley, toe a dam and power plant 

of the Montana Power Co., which form one of the units in a system 

that supplies a large part of the State with hydroelectric power and 

light. The dam impounds a body of water several miles long, 

known as Lake Sewell, which has a picturesque setting east of 

the Spokane Hills. Between Winston and Toston the valley is 

traversed by the Northern Pacific Railway, and between Winston 

and its extreme southwest limit by the automobile highway known 

as the Geysers to Glaciers Trail. Both routes pass through Townsend.

FIELD WORK

Within the period July 10 to August 28, 1921, 'an examination of 

Townsend Valley was made by the writer to obtain information

/ ' .,' 1,
2 GEOLOGY AND GROUND WATEB, TOWNSEND VALLEY, MONT.

about the geology and ground water and in particular to determine 

whether flowing wells could be obtained on the unirrigated " bench 

lands."

O 25 SO 75 iOOMILES

Area covered by this report Principal intermontane valleys

FIGUEBI. Index map showing location of Townsend Valley. 1, Flathead Valley; 2t 

Kalispell Valley; 3, Little Bitter-root Valley; 4, Mission Valley; 5, Missoula Valley; 6, 

Blackfoot Valley; 7, Bitterroot Valley; 8 Flint Creefc .valley; 9, Deer Lodge Valley; 

10, Avon Valley; 11, Prickly Pear Valley; 12, Tovmsend Valley; 13, Smith River 

valley; 14, Gallatin Valley; 15, Madison Valley; 16, Jefferson Valley; IT, Beaverhead 

Valley; 18, Silver Bow Valley; 1&, Big Hole Valley; 20, Lemhi Valley; 21 Pahsimeroi 

Valley; 22, Centennial Valley.

SUMMARY

Townsend Vialley is one of several broad basin-like depressions that 

diversify the mountainous part of southwestern Montana. It includes broad lowlands that adjoin the main streams and moderately 

elevated " benches " that project from the mountains toward the in-
.....If ,; r,- 5EISTOEX OF SETTLEMENT ... ,;.,., 3

terior of the vaUey-. The rocks consist ,of two groups separated by a> 

majpr-iiBconfoaanijty,: The older groi|p jincludes a.greatjhickness of, 

quartzite, sliale, and limestone that range in age from pre-Cambaian. 

to.,Cretaceous aad-,have .been severely defonned and,deeply erode^ 

Associated with these beds are intrusiyeaiid.e^Etrasive igaepus rocks, 

chiefly of .Cretaceous or early Tertiary age. These rooks wmppse the 

mountains and in the valley form, the bedrock. upon; which the 

younger rocks lie. , . . - : . : ,, ; , 

The younger group, which occupies most of the valley, includes 

beds of Oligocene, Miocene, Pleistocene, and Becent age* The Oligocene beds consist chiefly of light-colored and moderately hardened 

clay, composed of fine volcanic ash. The Miocene beds are made up 

chiefly of incoherent sand and gravel. The beds of these two series are 

moderately deformed, are separated by an unconformity, and yield, 

vertebrate fossils that include the remains of extinct species of borses, 

camels, and other animals. The Pleistocene deposits consist chiefly 

of gravel that overspreads the benches and underlies the valley bot-, 

toms. In addition the valley contains a small amount of Becent 

alluvium.

Ground water that is hard but potable and suitable for most ordinary uses is found near the surface in the lowlands and at depths 

ranging from 100 to 300 feet in the bench lands. In most places the 

ground water is abundant; its chief sourcfe is seepage from the mountain streams, and it is extensively used for domestic and public 

supplies.

In the valley generally conditions are unfavorable to the occurrence of ground water under sufficient pressure to produce flowing 

wells.

The valley contains beds of diatomaceous earth, and OB the bordering slopes are outcrops of marble that are undeveloped but doubtless 

are of future value. In one place a small bed of rather poor eoal is 

exposed.

HISTORY OF SETTLEMENT

In 1805 the historic expedition of Lewis and Clark, on its way to 

the Pacific coast, passed through Townsend Valley. On July 20 of 

that year Captain Clark, who with a small party was scouting on 

foot ahead of the expedition, 'entered the valley near Winston over 

practically the same route as that now followed by the railroad and 

the automobile highway. That night Clark and his companions, 

who were the first white men .to enter or see this valley, camped on 

the river above the mouth of Beaver Creek.1 The next day, July 21,

1 Original journals of the Lewis and Clark expedition, 1804-1806, edited by Reuben 

Gold Thwaites,, vol. 2, pp. 254-270, Dodd, Mead & Co., 19O4.
4 GEOLOGY AND GROUND WATER, TOWNSEND VALLEY, MONT.

Captain Lewis with the main party, coming up the river in boats, 

reached a point near Canyon Ferry. In his journal of that date 

Lewis recorded that before Mm stretched a beautiful and extensive 

plain lying between high mountains whose summits still sfeowed 

patches of snow. It took the members of thfc expedition four days 

to work their passage upstream as far as the gorge above Toston, 

During this time they made overnight camps on islands in the 

river below Confederate and Indian creeks and on the west bank 

nearly opposite the mouth of Dry Creek. The explorers referred 

to Beaver Creek as White Earth Creek and named the streams 

now known as Confederate Creek and Crow Creek, respectively, 

Whitehouse Creek and Oass Creek, after members of the expedition. 

In July of the next year, on their return, Sergeant Ordway and 

10 men of the expedition again passed through the valley, descending 

the river in canoes, Lewis and Clark with the remaining members 

having separated, each taking a new route through this part of the 

country.

After the departure of Lewis and Clark nothing oi importance 

occurred in Townsend Valley or its neighborhood, so far as known, 

until 1864, when gold was discovered in gravel on Confederate 

Creek. Other discoveries followed, including the pla<5ers on White 

Creek and Cave Creek and at Radersburg and many other places, 

and for several years the region contained a large but fluctuating 

population engaged chiefly in placer mining.

The gravel along Confederate Creek proved to be the richest 

ever found in Montana. Some of it yielded as much as $1,000 to 

the pan,2 and one season's " clean-up " from the placers on the terrace 

known as Montana Bar is said to have been 2^4 tons of gold, worth 

about $900,000.

During the mining period several towns or villages came into 

existence, of which Diamond City, on Confederate Creek, quickly 

became the metropolis of the general region and one of the most 

celebrated boom mining camps in the West. The less prominent 

settlements included Cavetown, Radersburg, and two small camps ton 

the bench north of Indian Creek that had the suggestive titles 

Hog'em and Cheat'em. Among the stirring events of that time was 

 a bloody battle near Cavetown in which an organized gang of claim 

jumpers was badly worsted by the miners.

A decade after their discovery the placers of Confederate Creek 

had been largely worked out and abandoned, and a few years later 

placer mining in the neighborhood of Townsend Valley had declined 

to relatively small proportions. Of the several mining camps Radersburg is the only survivor, and its persistence is due to the dis2 The amount called by the miners "a pan" was usually two ordinary shovelfuls.
TOPOGBAPHY

covery of m^tal-bearing lodes in tne hills

has dwindled1 to a few deserted cabins, 

to have vanished completely.

Since the early days of mining the de 

proceeded steadily in Townsend. Yalley, 

exceed in aggregate value the tons of 

earlier a\nd more spectacular period, 

chiefly- in' cutting wild hay from the natural 

lowland^. Later, with the aid of irri 

valley became cultivated and a wider 

grains, were grown. There remained 

" bench lands," for which no water was 

years agb hardly any attempt was made 

were used chiefly as pastures and runwa 

the development in recent years of dry-f 

of these unirrigated lands have been oc 

tempts to cultivate them have met wi 

period that began in 1917 was so severe 

ley that several of the dry farmers became

near by. Diamond 

md the other cfanips ttppear

elopment ot agriculture has 

md already its products far 

gold produced during the 

At first farming consisted 

meadows or subirrigated 

atiori, a large Jpart of the 

variety of crops, including 

i considerable area, chiefly 

'available. Until a few 

o cultivate these lands; they 

s for stock. However, with 

rming methods a large part 

upied by settlers, whose ath varying success. A dry 

in parts of Townsend Valliterally starved out.

TOPOGRAPHY

PRINCIPAL FEATURES

a ad

Townsend Valley is a broad depress! 

lies between two moderately high and 

main axis is a curve concave to the west 

the valley ranges from a little east of n 

northwest in the northern part. Along 

side the valley is bordered by the Belt 

unbroken barrier from 2,000 to 4,000 i 

summits of this range, Mount Baldy 

altitude of 9,600 fee.t above sea level. Ch 

of the valley is bordered by the similar 

Elsewhere the rim is comparatively low. 

the Elkhorn Range and the Belt Mountains 

kane Hills, an uneven divide about 1, 

southern third of the basin the rim is a 

from the Belt Mountains between Sixi 

west as far as Toston and thence south 

lowland west of Toston to the south end

South of Toston this ridge.is cut by 

sovtri River enters the basin; at the nortl 

and the Belt Mountains, is another gorge

104142 25 2

>n about 60 miles long that 

;ged mountain ranges. The 

and therefore the trend of 

>rth in the southern part to 

nost of its eastern or convex 

Mountains, which form an 

eet above the valley. Two 

Mount Edith, attain an 

the west the middle stretch 

y elevated Elkhorn Range. 

At the northwest, between 

, it is formed -by the Spofeet high. Around the 

ide, low ridge that projects 

lile and Sixteenmile creeks 

ard and curves around the 

of the Elkhorn Range. 

gorge through which Mis- 

, between the Spokane Hills 

through which the river

,000
6 GEOLOGY AND GROUND* WATER, TOWNSEND VALLEY, MONT.

escapes. Between the Spokane Hills and the north end of the Elkhorn Range is a low, wide gap occupied by the Northern Pacific Kailway and the Geysers to Glaciers Trail. Around the south end of the 

valley southwest of Toston the rim, though unbroken, is low for a 

considerable distance. At the extreme south it is crossed by the 

Geysers to Glaciers Trail.

Townsend Valley is one of several basin-like depressions that 

occur within tne mountain region of western Montana. Its nearest 

neighbors are on the northwest Prickly Pear Valley, in which the 

city of Helena is situated, and on the south the large basin known 

as the Madison-Gallatin or Three Forks Valley. A short distance 

to the east, across the Belt Mountains, is the valley of Smith Eiver 

(sometimes called Deep Eiver), and just across the low,rim at the 

southwest is a smaller basin drained by Boulder Eiver. The more 

distant basins include Jefferson, Beaverhead, an4 Big Hole valleys, 

on the upper waters of the Missouri, and Deer Lodge, Avon, Flint 

Creek, Bitterroot, and Missoula valleys, in the Clark Fork drainage 

area. ,

The general altitude of Townsend Valley is between ,4,000 and 

4,500 feet above the sea. Along Missouri Eiver the altitude ranges 

from 3,650 to 3,900 feet. From both sides of the river the surface 

rises gradually toward the mountains, at the foot of which it is 

from 500 to 1,200 feet higher than at the river.

The most noteworthy surface features of Townsend Valley are 

gently sloping plains at different levels. Together they occupy more 

than half of the valley, and most of them are included in four principal sets or groups that occur one above another. The lowest set 

includes the valley bottoms or lowlanqls that border the streams. 

The other three sets are made up of the more or less higher features 

known as " benches " that occur in the interstream areas and extend 

for greater or less distances out from the mountains. Commonly 

the "benches," together with the slopes or escarpments that separate them from one another or from the lowlands, are spoken of 

collectively as the "bench lands." The lowlands and the bench 

lands together cover nearly three-fourths of the valley. The remainder of its surface may be classified chiefly as uneven or hilly lands*

BENCHES

A large part of Townsend Valley consists of nearly flat areas 

that stand at moderate heights above the lowlands adjoining1 th& 

streams. These are clearly the remnants of ancient river plains, 

alluvial fans, and possibly other nearly flat surfaces. The higher 

ones surmount the divides between the principal streams and com-
TOPOGRAPHY 7

monly take the form of flat-topped ridges and plateaus. Most of 

the lower ones are shelves or terraces. In accordance with, the 

custom of this general region the term " bench " is used herein for 

convenience to include the features mentioned above and in addition 

any other remnants of the ancient plains referred to. As thus used 

the term is practically synonymous with " remnant of an ancient 

moderately elevated plain." In a belt 2 to 10 miles wide that extends 

along the east side of the valley from Canyon Ferry to Toston and in 

a smaller area west of the river that lies north and south of Beaver 

Creek the benches are separated from one another and from the 

valley bottoms by abrupt steep slopes or escarpments. Along the 

west side of the valley between Winston and Indian Creek and in 

the southern part south of Crow Creek .considerable areas are covered 

by smoothly sloping, surfaces that lie above the valley bottoms but 

are not themselves terraced or otherwise separated into plains at 

different levels. Presumably they include the different benches as 

well as the slopes that separate them and therefore are to be classified as bench lands.

Beginning with the highest the different benches described herein 

are designated No. 1,, No. 2, and No. 3. All are remnants of plains 

approximately parallel to one another and to the valley bottoms 

which form the fourth and lowest plain of the series., In most plaices 

bench No. 3 is less than 50 feet higher than the valley bottoms adjacent to it. Bench No. 2 is generally from 100 to 150 feet»above No. 

3, and No. 1 from 50 to 100 feet above No. 2.

Bench No. 1 (PL I, A) occupies considerable areas on the east side 

of the valley south of Deep Creek, where it extends from the mountains well out into the valley. Between Deep Greek and Greyson 

Creek it is a smooth plain that rises toward the mountains at an 

average rate of about 70 feet to the mile. Along Grey son. Creek it 

is parallel to and about 150 feet above the valley bottom. Along 

Deep Creek, however, the valley bottom rises less steeply than the 

bench and lies from 175 to 250 feet below it. Between Greyson Creek 

and Dry Creek bench No. 1 is a generally smooth plain rudely parallel to the valley bottoms on either side and from 150 to 200 feet 

higher. Near the mountains its slope is about 150 feet to the mile. 

South of Dry Creek the bench rises toward the southeast at the rate 

of 100 feet or more to the mile and attains an altitude of 500 feet 

above the bottoms along Sixmile Creek. From Deep Creek north 

to Gurnett Creek bench No. 1 does not extend far out from the mountains. Its slope ranges from 100 to 200 feet to the mile, and at its 

extreme upper limit, at the foot of Mount Baldy, it attains altitudes 

ranging from 5,400 to 5,600 feet. Between Gurnett Creek and Hell-
8 GEOLOGY AND GBOI7ND WAITER, T0WNSEND VALLEY, MONT.

gate Creek, a distance of 18 or 20 miles, : bench No. 1 is practically 

limited to a few small areas along Confederate Creek, 'some of which 

are well within the mountains and- attain slopes ranging from 200 

to 300 feet to the mile and an extreme altitude of 6,200 feet. In the 

north end of the valley adjacent to Cave Creek, tench No. 1 covers 

a small area about 250 feet above the valley bottoms and exhibits 

slopes ranging from 100 to 200 feet to the mile, but it is not very distinctly separated from bench No; 2. West of the river on both sides 

of Beaver Creek bench No. 1 rises westward at the rate of 100 feet to 

the mile and lies from 200 to 300 feet above the adjacent valley 

bottoms.

Bench No. 2 covers a considerably greater total area than bench 

No. 1 and next to the valley bottoms is the most extensive of the 

plainlike surfaces being considered. East of the river it occupies 

most of the bench lands between Gurnett Creek and Hellgate Creek. 

Here it lies from 50 to 100 feet below adjacent areas of bench No. 1 

and is from 100 to 150 feet higher than the valley bottoms. South 

of Gurnett Creek bench No. 2 is composed of terraces that lie in 

front of bench No. 1 and are from 75 to 100 feet lower. Along Cave 

Creek this bench occurs at a level about 50 feet below bench No. 1 

and consists of narrow terraces or " bare " that have been mined for 

gold. The famous Montana Bar and other gold-bearing terraces 

along Confederate Creek are probably parts of bench No. 2. West 

of the river this bench was not identified unless it is represented by a 

narrow terrace north of Beaver Creek at a level 200 feet below bench 

No. 1.

Bench No. 3 occupies comparatively small areas on the east side 

of the valley between Gurnett Creek and Toston and on the west 

side of the valley below Beaver Creek. It consists of shelves or 

terraces a few rods to 8 miles wide that lie in front of bench No, 2 

and are from 50 to 100 feet lower than that bench and 80 or 40 feet 

higher than the valley bottoms.

VAI«LEY BOTTOMS

Nearly one-third of the area of Townsend Valley consists of low 

lands that border the streams. Along Missouri Kiver, Crow Creek, 

and Warm Spring Creek these lands range from 1 to 5 miles in 

width. Along the other streams they are much narrower. Their 

slope varies in agreement with the gradients of the streams they 

border. Those along Missouri River descend northward at an average rate of 5 or 6 feet to the mile. Those along the tributary streams 

descend eastward or westward, as the case may be, at rates ranging 

from 40 or 50 to 100 feet or more to the mile. In addition they rise
U. S. GEOLOGICAL SURVEY [WATER-gUPPLY[>APER 539 PLATE I

'A. BENCH NO. 1

5. ; clay

'. *...*..! i j*i

Miocenes 

No. 2 bench, gravel 

* ° i 

i

i

B. OLIGOCENE BEDS TRUNCATED BY BENCH NO. 2
t,. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 539 PLATE II

A. MARBLE (CAMBRIAN LIMESTONE) SOUTHWEST OF TOWNSEND

B. LAKE SEW ELL AND SPOKANE HILLS
DRAINAGE 9

gradually away from the streams. Small parts are subject to overflow, but most of them are above the 'reach of floods and are therefore hardily to be regarded as flood plains. For convenience the 

term " valley bottoms," which is in common use in this region, is applied to them herein. Together the valley bottoms compose a continuous plain, the larger part of which forms a belt that extends from 

one end of the valley to the other and li«s considerably to the west 

of the valky's axis. The remainder of the plain is made up of the 

narrow branches that extend from the main part up along the side 

streams to the points at which they issue from the mountains.

HILLY LANDS

On" the sides of the valley near the mountains are some areas of 

rough or hilly lands, the largest of which is a chain of hills that extends from Gurnett Creek to Confederate Creek and rises slightly 

above bench No. 1. A low rounded hill east of Winston, a rather 

high and prominent butte south of Radersborg, known as Lone 

Mountain, and a small but rugged knob southeast of Warm Spring 

Creek stand well out in the valley. A small but noteworthy feature 

is the canyon or gorge of Missouri Kiver at Canyon Ferry. Here the 

river leaves the open valley for a short distance and passes through 

a narrow trench that is cut from 100 to 200 feet deep across a short 

spur of the Spokane Hills. If the trench were filled the river would 

be forced to flow through the open valley and around the end of the 

spur. The river cut this trench at a time when the valley, as explained on page 43, was obstructed by sediment that since then has 

been eroded away.

DRAINAGE

Missouri River enters Townsend Valley through a gorge at the 

southeast above Toston and leaves it through another at the northwest below Canyon Ferry. Between these points its course lies near 

the west side of the valley, and it receives several tributaries whose 

sources are in the neighboring mountains. At Toston the altitude 

of the river is approximately 3,900 feet. Between that point and 

Canyon Ferry, a distance of 48 miles measured along its somewhat 

winding course, the stream descends 250 feet, or a little more than 

5 feet to the mile.8 Measurements at Toston during the years 1911 

and 1913 to 1915 show the mean annual flow of the river to range 

from 5,060 to 6,990 cubic feet per second, the average being about 

5,800 cubic feet per second. The maximum and minimum flows were 

29,800 and 1,100 cubic feet per second.4

8 U. S. Geol. Survey Water-Supply Riper 367, pi. 1, 1914.

* U. S. Geol. Surrey Water-Supply Papers 306, 356, 386, and 406.
10 GEOLOGY AND GROUND WATEBj TOWNSEND VALU3Y, MONT.

Nine or ten perennial streams issue from the Belt Mountains on 

the east side of the valley,' and two from the Elkhorn Mountains on 

the west. All of them have steep gradients. Deep Creek, for «xample, in its course of 12 miles between the mountains and the river, 

* falls 600 feet, as determined by aneroid barometer, or at an average 

rate of 50 feet to the mile. Similar determinations show the gradient of Crow Creek to be 50 fget to the mile, Greyson Creek 68 

feet, Beaver Creek 100 feet or more, and the remaining streams from 

50 to 100 feet. Detailed surveys would show that the profiles of 

these streams are slightly concave upward; their gradients generally 

become somewhat steeper upstream as the mountains are approached. 

So far as known these streams have not been systematically measured, but their average aggregate summer flow is estimated 5 .to 

range from 65 to 100 cubic feet per second. About two-thirds, of 

this amount is discharged by the streams on the east sicje., Deep 

Creek on.the east and Crow Creek on the .west are about equal in 

size and together discharge about half of the total estimated volume. 

JJetween the mountains and the river all the streams lose more or 

less water by seepage into the gravel beneath their beds, and during 

the dry season they are reduced a little by evaporation but most 

of them maintain a perennial surface, flow to the river,

VEGETATION

The mountains are partly covered with a forest of pine! and fir. 

The valley is practically bare of timber, except for cottonwoods and 

willows that line the streams and scattering cedars or junipers on 

some of the steep and sunny slopes. In most places the predominant 

vegetation is of the bunch-grass type or was until destroyed by overgrazing or plowing. Sagebrush and similar shrubs are plentiful 

in some areas, and two or more species of cactus or prickly pears 

are rather widely distributed. Where the land has been overgrazed 

or abandoned after cultivation the place of the native bunch grass 

is taken by weeds of comparatively small forage value.

CLIMATE

The Townsend Valley possesses a dry temperate climate characterized by abundant sunshine, bracing atmosphere, cool summer nights, 

and other attractive features. Records of the United States Weather 

Bureau at Helena and Three Forks, Mont., which are near the Townsend Valley and have similar climate, show the following averages 

and extremes:

6 Holloway, T. L«., Townsend, Mont., personal communication.
CLIMATE 

Climatic data at Helena anA Three JPorfcs, Mont.

11

Normal monthly 

temperature (°|y:

Three Forks. 

Highest temperature on record 

("*.):

Three Forks . 

Low,e$t temperature 'on record 

(°F.):

Three Forks . 

Normal rainfall 

(inches):

Three Forks. 

Normal snowfall 

(inches):

Three ForksAverage number 

of days with 

measurable 

amount of precipitation:

Three Forks .

Length 

of 

record

(years)

26

19 

40

5

no

5 

41

9 

29

5

00

5

Jan.

M

20 

BS 64 J

A9

-30

ft Q9

.31

11,5

4.0

4

Feb.

99 '

24 

65

67 

-41

-29 

fl| 66

.34 

8,0

4.7

7

4

Mar.

11

, 32

7O

79

on

-19

0,76

.40

9

K

2.9

4

Apr.

49 '

43

8675' 

6

10 

1 06

.88 

5 8

2.7

5

May

5?,

53

Q1

95 

22

22

9 1 e

1.62 

1 4

1.9

19

8

June

61

62 

102

100

*>1

29

3 -in

2.46

I1 rap A

0

19

6

July

67

67 

103

Ml

Qfi

32

O QA

1.39 

0

0

4

Aug.

66

65

OR'97

90

28 

0.69

 66 

0

0 

5

6

Sept.

56;

55

GO

91 

20

23

1.25

1.44 

0.6

.2

7

6

Oct.

44

43 

'83 84

-1

-9

A QA

1.02 

3.1

2.3 

6

6

Nov.

so

30

71

68

99

-21 

0.71

.61 

6.6

4.9

7

4

Dee.

26

. 22 

64

59 

_ 40;

-43 

0.76

.49 

8.1

4.4

17

Annual

43

,43 

103

 ior

__4*Tj

-43

13.81

11.53

54.7

28.0 

97

74

Average date of last killing frost in spring:

Helena___________________ ... . _ __________________May 7 

Three Forks_._._........._.____...__......_________ .*_______May 29

Average date of first killing frost in autumn:

Helena..._________________________________________ September 28 

Three Forks________________________________________ September 11

As a rule the extremes of heat and cold are easily endurable because of the prevailingly dry atmosphere. In the summer refreshing 

local showers or thunderstorms of shortt duration are moderately 

frequent. Generally these storms cross the valley from west to east, 

and occasionally they cause washouts or damage by hail. In any 

one season they may be more frequent in one part of the valley than 

another, but in the course of time they appear to cover all parts 

about equally. In the area considered arid in the surrounding region 

as well it is evident without the aid of detailed records that the 

mountains receive a much greater precipitatiori than, the valleys. 

A large part of the excess falls as snow during the winter, but in 

summer also it rains more frequently and copiously on the mountains than in the valley. "Within the valley itself the precipitation 

appears to be greater near the foot of the mountains than elsewhere. 

This inference is supported by the records, which snow that Helena, 

situated at the foot of a mountain range, receives about 2 inches more 

precipitation annually than Three Forks, which is near the middle 

of a wide valley.
12 GEOLOGY AND GBOUND WATER, TOWNSEND VALLEY, MONT.

So far,as dry-farming methods have been developed in Townsend 

Valley it appears that, other conditions being favorable, the average 

annual rainfall here is barely sufficient for the growing of profitable 

crops. Therefore, the cyclic variations in precipitation described 

below have to a great extent controlled the growth of dry farming 

in this region. The time covered by the records at Helena may be 

divided into alternating wet and dry periods, each of which is about 

nine years long. (See fig. 2, a.) Two successive periods form a 

cycle that includes the changes through dry to wet and back to dry 

again. The record begins in 1881 at the beginning of a dry period, 

comprehends two complete cycles, and ends (1922) in the middle of a 

dry period that apparently is to form the first half of a new cycle.

FIGUBB 2. Variations In precipitation at Helena

Within each period there are minor fluctuations that tend to modify 

but do not alter its dominant character. Among other variations in 

distribution, the most noticeable is a yearly wet season that may 

extend through parts or all of May, June, and July but generally 

reaches its height early in June. (See fig. 2, b.) The recorded rainfall for this season ranges from more tihan 10 inches to less than 2 

inches and averages nearly 6 inches or about two-fifths of the mean 

yearly total. The seasons that show more than average rainfall and 

those that show less can be grouped to correspond with the periods 

of wet and dry years (fig. 2, b.) Exceptions are shown in 1917, 

when the spring rainfall was less than the average, though the rainfall for the year was more; and in 1913 and some earlier years, 

when the reverse was true.
PRE-TERTIAB.Y ROCKS 18

Before the latest wet period began dry farming had not been undertaken extensively in Townsend Valley. The results obtained 

since then indicate that generally fair to good crops may be expected 

during the wet periods and rather poor crops or none at all during 

the dry period. The fact that the wet season comes in the spring is 

favorable, and occasionally the rainfall at that time is enough to 

overcome the effect of a dry year. Whether the cyclic variations 

described will continue can not he predicted, owirfg to the uncertain 

character of weather changes generally. '

GEOLOGY

PRE-TEBTIARY BOCKS 

8TRATIGBAPHY

Rocks ranging in age from pre-Cambrian to late Cretaceous or 

possibly early Tertiary form the mountains and probably constitute 

a, bedrock floor that extends across Townsend Valley beneath the 

Tertiary and later deposits. (See fig. 3.) Shale and sandstone belonging to the pre-Cambrian Belt series crop out in the Spokane 

Hills, in the canyons of Greyson Creek and Deep Creek, and at many 

other places around the edge of the valley. At the mouth of Deep 

Creek canyon is an exposure of dark-colored shaly rocks and quartzite that belong to the Greyson shale, a formation named by Wal-

 cot^ 8 from Greyson Creek and of particular interest because it 

contains pre-Cambrian, (Algonkian) fossils. On the ridge between 

Deep Creek and Greyson Creek this formation has a measured thick* 

ness of 3,000 feet. The Spokane shale, so named by Walcott 7 

because of its occurrence in the Spokane Hills, near the northwest

 end of Townsend Valley, lies stratigraphically next above the Greyson shale. In the canyon of White Creek east of the Spokane Hills 

this formation attains an estimated thickness of 1,500 feet. It consists chiefly of deep-red shale with some laj^ers of green shale and 

ripple-marked sandstone and varieties of these rocks that may be 

termed argillite and quartzite.

Rocks of Paleozoic age appear on the lower slopes of the Belt 

Mountains, on the spur southwest of Townsend, and at other places 

around the edge of the valley. On the spur southwest of Townsend, 

west of the area of red Spokane shale, are several conspicuous outcrops of Paleozoic limestone, with which some layers of quartzite 

and shale are interbedded. The exposures include beds of Cambrian, 

Devonian, and Carboniferous age that aggregate 4,000 feet or more

« Geol. Soc. America BtilL, vol. 10, p. 206, 1899. 

'Idem, p. 207.

104142 25 3
14 GEOLOGY AND GROUND WATEB, TOWNSEND VALLEY, MONT.

TERTIARY- CRETACEOUS TO 

1 Miocene md PRE-CAMBRIAN

Valley gravel Bench gravel Sand, gravel, clay, Sedimentary Strike and Horizontal bed Trace of fault

and volcanic ash rocks and ittttti- dip of strata flj, upthrow;

sive granitic Q downthrow)

rocksandlava Arrow d»W8direeno1** tkm of overthrust

FIGURE 3. Geologic map of Townsend Valley. A-A', Line of section In Figure 5
PB&~ZEBXZAS7 BOCKS . ,- ':.. §

in thickness; Altogether five different beds of limestone appear 

that range from black to light gray or wMte in color, ami in inaay 

places possess the texture of fine-grained marble (PI. II, 4K 

the slope facing Townsend Valley north and south of 

Creek the Madison limestone appears in rough and «onspieu^ua outcrops and forms the imposing walls and crags at the mouth of Avalanche Creek canyon.

Bocks of Mesozoic age are rather poorly exposed along the southwest margin of Townsend Valley, in the western part of T. 3*N., B. 

1- E. Here they consist chiefly of gray to red sandstone and sandy 

shale that probably belong to the Ellis (Jurassic) and Kootenai 

(Cretaceous) formations. In the hill south of Sixmile $reek, about 

3 miles east of Toston, variegated shale and sandstone that probably 

belong to the Kootenai are exposed.

Bocks of igneous origin are associated with the pre-Tertiary sediments at several places around the margin of the valley. The butte 

south of Badersburg, known as Lone Mountain, and the mountain 

slopes west of Badersburg and Winston are formed of an andesitic 

lava of probable Cretaceous age that came to place as flows, tuffs, 

and breccias. Generally this rock is heavy and dark colored, and 

commonly it shows small porphyritic crystals of light feldspars or 

dark hornblende or pyroxene. At several places, including the 

neighborhoods of Badersburg and Winston, the andesite contains ore 

deposits that are valuable for gold, silver, and -other metals.

Granitic rocks intrusive into the pre-Tertiary sediments occupy a 

considerable area at the eastern margin of the valley north of Ray 

Creek. At Canyon Ferry a granitic rock (monzonite or granodiorite) of rather coarse texture and medium-gray color forms a natural 

foundation and supplies the material for the Montana Power Co.'s 

dam and power house. A light-gray fine-grained granite or related 

rock projects as a small ragged knob above the bench lands southeast of Warm Spring Creek. At the mouth of the canyon of Sixmile 

Creek, east of Toston, is a large dike or sill of. a dark greenish-gray 

crystalline rock( diorite or diabase) that has shared in the deformation of the inclosing sediments and therefore is probably older than 

the other igneous rocks mentioned.

The limestone, shale, and other bedded rocks mentioned in the foregoing paragraphs are everywhere severely def ormed. , As a result of 

extensive $arth movements the beds, which originally were horizontal, 

have been bent into arches and troughs, broken and dislocatecj .by 

faults, and in general made to incline at angles nearer the vertical
16 GEOLOGY AND GROUND WATEB, TQWNSEND VALLEY, MONT.

than the horizontal. (See figs. 4 and 5.) On the mountain spur 

southwest of Townsend the Spokane shale is bent into an arch whose 

east side dips moderately toward the valley. The west side is steep 

and involves a great thickness of beds in addition to the Spokane, 

including the Cambrian marbles, most of which stand practically on 

edge. In the Spokane Hills, the type locality of the Spokane shale, 

the beds are bent into an open trough or syncline. On the east side 

of the valley beds of Paleozoic limestone exposed at the mouth of 

Gave Greek canyon are bent into a sharp arch that trends northwest 

(fig. 5). White Greek cuts through a similar arch, and at many 

places from that point south to Sixmile Creek steeply tilted beds are 

exposed. Along the southern edge of the valley southwest of Toston 

the dips are westward at moderate angles.

FIQDBB 4. Geologic section north, of Sixmile Creek, showing faults ia Tertiary sand, clay,

and conglomerate

A'

BELT MTS.

FIGUBB 5. Geologic section near Canyon Ferry, along line A-A', Figure 3. Q. Quaternary ; T, Tertiary; l£, Cretaceous to pre-Cambrian

A large overthrust fault described by Haynes 8 extends through 

the hills south of Toston and is well exposed in the gorge of Missouri 

Biver at the double horseshoe bend below Lombard. It trends northward, dips moderately to the west, and has been traced for- a distance 

of 13 miles. West of this break the rocks have been thrust upward 

and over the rocks east of it so far that in one place Belt rocks overlie beds of Cretaceous age. The extensive displacement thus indicated is thought to have occurred at the end of Cretaceous time or the 

beginning of the Tertiary.

Faults that appear to be normal, or in other words faults whose 

hanging walls appear to have fallen relative to their footwalls, were 

observed near the margin of the valley at Gave Creek, White Creek, 

and Sixmile Creek. Those at Cave Creek and White Creek trend 

northwest and cause Belt rocks on the east to abut against Paleozoic 

rocks-on the west that is, the blocks on the valley ward sides of the 

faults are downthrown (fig. 5). The fault on upper Sixttrile Creek

8 Haynes, W. P., The Lombard overthrust: Jour. Geology, vol. 24, pp. 269-280, 1916.
38OCKS * 17

shows a downward displacement on the valley side and is otherwise of interest because it cuts both Paleozoic and Tertiary rocks. 

Presumably these normal faults are all of the same age, and the one 

last mentioned is evidently Tertiary or later.

TERTIARY ROCKS

LrrERATURE

Previous descriptions of the Tertiary rocks of TownsenA Valley 

are limited to reports by Douglass (see Nos. 11,13,16, and 18 below), 

which deal chiefly with the vertebrate fossils, and a report by Jennings (No. 23), which gives a small list of fossil plants and discusses 

their relations. The Tertiary beds of Townsend Valley, however, 

are similar to those of the neighboring valleys in the mountainous 

region of western Montana, and as a guide in studying them the 

principal reports describing the Tertiary of all these valleys are 

listed below in the order of their publication:

1. Hay den, F. V., U. S. ,Geol. and Geog. Survey Terr. Fifth Ann. Rept., p. 33, 

1871. Mentions the occurrence of light-colored marl and sandy clay in the 

valley of Red Rock Creek, southwestern'Montana. The beds attain a thickness of several hundred feet and dip 5° W. They were found to contain fossil 

remains of a small three-toed horse (AncMtherium) and a snail (Helix).

3. Leidy, Joseph, U. S. Geol. Survey Terr. Rept., vol. 1, pp. 251, 252, 323,1873. 

Describes the fossil horse (Anchitherium agreste) found by Hayden in the 

valley of Red Rock Creek. (See No. 1.)

, 3. Grinnell, G. B.. and Dana, E. S., On a new Tertiary lake basin: Am. Jour. 

Sci., 3d ser., vol. 11, pp. 12&-128, 1876. Describes Tertiary beds, found in the 

valley of "Deep Creek" fnot the Deep Creek of Townsend Valley But Smith 

River, sometimes called Deep River] in the neighborhood of Camp Baker 

[Fort Logan, just east of the area shown on fig. 3]. The beds are horizontal, 

consist chiefly of homogeneous cream-colored clay, and closely resemble the 

Miocene beds at Scotts Bluff, near North Platte River in Nebraska. In bluffs 

about 3 'miles southeast of Camp Baker a lower and an upper series of beds 

are exposed. The lower beds [later named Fort Logan beds] attain a thickness of 200 feet, the upper beds 50 feet, and the two are separated by 6 feet 

of hard sand with layers of small pebbles. In the lower beds were found a 

species of rhinoceros, several species of Oreodon and Eporeodon, a canine 

tooth, and remains of turtles. In the upper beds the principal fossils found 

were a species apparently of Merychyus, a small horse, and turtles. The 

authors refer to the lower beds as Miocene and to the upper as Pliocene.

4. Cope, E. D., Descriptions of new Vertebrata from the upper Tertiary 

formations of the West: Am. Philos. Soc. Proc., vol. 17, 1878. Describes (pp. 

219-223) several mammalian species from the upper beds in the Smith River 

valley which he correlates with the "Loup Fork" of Nebraska. ("Loup 

Fork" is no longer used as a formation name because in the early reports it 

was applied to several distinct units.)

5. Cope, E. D., The relations of the horizons of extinct Vertebrata of Europe 

and North America: U. S. Geol. and Geog. Survey Terr. Bull., vol. 5, pp. 50- 

52, 1879. The author divides the "Loup Fork" into lower and upper parts 

which he calls, respectively, " Tichoteptus beds " and " Pror&melw beds"; the 

former is the upper part of the Tertiary beds on Smith River called Pliocene 

by Grinnell and Dana. (See No. 3.)
18 GEOLtfGY AND GROUND^ WATBB, .'HQWNSEND' VALI^EY, MONT.

6. Oope, E. D., On two new species, of three-toed horses from the upper 

Miocene, with notes on the fauna of the Ticholeptus beds: Am. Philos. Soc. 

Proc., vol. p. 539, 1886. Gives a list of mammalian species from the " Deep 

Eiver " [Smith River] " Ticholeptm beds," including a deer, a horse, a camel, 

a mastodon, and several oreodonts.

7. Scott, W. B., Mammalia of the Deep River beds: Am. Philos. Soc. Trans., 

new ser., vol. 18, pp. 56-185, 6 pis., 1895. Describes the results of the Princeton 

geologic expedition of 1891 to the valley of "Deep River" [Smith River]. 

The two formations mentioned by Grinnell and Dana (see No. 3), to which the 

Deep River beds belong, differ widely in lithologic character, the upper being 

chiefly incoherent sand and the lower very hard clay. The two are separated 

by an eroslonal unconformity that probably represents a considerable lapse of 

time. In the lower beds (the Miocene of Grinnell and Dana) were found JO 

species of extinct mammals which were regarded as indicating a correlation 

with the John Day formation of Oregon. From the upper beds (the Pliocene 

of Grinnell and Dana and the. " TioHoleptus beds " of Cope) several new forms 

were obtained which, together with those previously reported by Cope, make 

a total of more than 20 species. The author concludes that these beds form a 

well-marked unit at the base of the " Loup Fork."

8. Peale, A. C., U. S. Geol. Survey Geol. Atlas, Three Forks folio (No. 24), 

1896. Describes the Bozeman " lake beds," which occupy an area of about 900 

square miles in the Gallatin and Madison valleys and neighboring basins, and 

assigns them to the Neocene. The lowest beds are made up of conglomerate 

containing pebbles of local origin. Above these is a great thickness of rusty 

or discolored volcanic dust with a few layers of pure-white dust, consisting 

of sharp, angular fragments of pumiceous glass. The upper beds, especially 

near the edges of the basins, contain materials derived from the erosion of 

the older rocks. In the main (Madison-Gallatin) basin the beds dip a few 

degrees eastward or northeastward. A thickness of 800 to 1,000 feet is shown, 

and-a total ttiickness of 2,000 to 2,500 feet is indicated. The beds are regarded 

as having been deposited in fresh-water lakes held.in basins that were practically the same as the basin-like valleys of to-day. In the summit of the 

bluffs along lower Madison River were found immense quantities of opalized 

wood and fossil bones indicating the Pliohippus zone of Marsh.

9. Douglass, Earl, The Neocene lake beds of western Montana, Montana University, 1899. The author points out the general similarity of the Tertiary 

lake beds in the different valleys of western Montana and observes that the 

presence of layers of pure volcanic ash is an almost constant feature. In 

several of the valleys fosils of White River and " Loup Fork " age have been 

found. In the lower Madison Valley the " Loup Fork beds," to the extent that 

they are exposed, include rather soft cream-colored clay and fine sand that 

form an upper part, and clay, sand, and gravel with layers of volcanic ash that 

form a lower part the whole about 500 feet thick. The lower part contains 

fossil wood and the remains of turtles, birds, clams, and fossil mammals, of 

which several new species are described. In a neighboring area are exposed 

beds that underlie the " Loup Fork." These aggregate 600 feet in thickness; 

the upper 400 feet consists of soft light-colored marl, volcanic dust, and fine 

sand; the remainder (200 feet) is made up principally of rather hard gray 

and yellow clay, fine sand, volcanic ash, and conglomerate. Fossil snails are 

found in the upper part, and mammals and turtles in the lower. Both girts 

are regarded as of White River age.

10. Douglass, Earl, A new species of Merycochoerus in Montana: Am. Jottr. 

Sci., 4th ser., vol. 10, pp. 428-438, 1900. Describes the skull of Merycbchoerus 

laticeps found in clay bluffs near New Chicago, Mont. A similar form was 

found in the " Loup Fork beds " of the lower Madison Valley.
TEBTIARY BOCKS 19

11. Douglass, Earl, Fossil Mammalia of the White Biver beds of Montana: 

Am. Philos. Soc. Trans.j new set., vol. 20, pp. 238-279, pL 9, 1902. Describes 

18 new species of mammals regarded as Oligocene, the fossils of which, together with the remainp of turtles, were found in light-colored clays of the 

" Pipestone beds " near (Whitehall, the " Thompson Creek beds " northwest of 

Three Forks, the " Blaoktail Deer Creek beds" southeast of Dillon, aind the 

"Toston beds" (pp. 242» 248), which are exposed in Townsend Valley a short 

distance northeast of Toston. Eight species from the "Toston beds" are 

listed namely, Hyaenofton montanus, Oreodon robustum, Eucrotaphus helenae, 

Colodon cinttulattts, Colod-on sp., Mesohippus, Titanotherinm, and Caenopus? 

The author concludes that the " Thompson Creek beds" apparently belong 

to the lower White Biver or Titanotherium zone, and that part at least of the 

"Toston beds" correspond more nearly to the younger Oreodon zone. In 

addition north of Avon in Avon Valley were found bone fragments regarded 

as Oligocene, and near' Drummond in Flint Creek valley fresh-water snails 

and plant remains in be«ls resembling the Oligocene and the remains of "Loup 

Fork" mammals in the overlying beds. The report contains a map (p. 241) 

showing approximately the - areas occupied by the Tertiary beds in southwestern Montana. ,

12. Matthew, W. D., The fauna of the Titanothenum beds at Pipestone 

Springs, Mont.: Am. Mus. Nat. Hisfc. Bull., vol. 19, pp. 197-226,1903. Describes 

more than 20 species of mammals the remains of which were found in soft 

reddish-brown to greenish-white clay with cross-bedded sandy layers.. Associated with the mammalian fossils are the remains of lizards and tortoises. 

At this locality the beds mentioned are steeply tilted and lie upon ancient 

crystalline rocks. Above them stratigraphically are the " Oreo&on beds," con* 

sisting of somewhat harder, less sandy, and more calcareous buff clays in which 

only a few determinable fossils were found. A lithologic distinction between 

the lower or " Titanotherinm beds" and the upper or "Oreo&on beds" was 

observed at other places in the neighboring region. The author concludes 

that the "Pipestone (TUanotherium) beds" are at the base of the Oligoeene 

but above the Eocene and are probably of about the same age as the White 

Biver beds of Swift Current Creek, Canada.

18. Douglass, Earl, New vertebrates from the Montana Tertiary: Carnegie 

Mus. Annals, vol. 2, pp. 145-200, pi. 2, 1903. Describes fossil remains representing more than 30 Species of mammals, two reptiles, and a fish. Most of 

the mammalian remains! were found in the "Madison Valley beds" south of 

Three Forks and the "Flint Creek beds" near New Chicago, both of which 

are regarded as Miocene. Two species from a locality northwest of Three 

Forks are described as White Biver Oligocene, four species, from beds exposed east of Drummond are regarded doubtfully as upper Oligocene, and his 

Sage Creek beds near Lima are regarded doubtfully as Eocene.«- The remains 

of one of the reptiles came from the White Biver beds on Pipestone Greek near 

Whitehall, the other came from " Loup Fork " Miocene in the lower Madison 

Valley, and the fish was* found in the Miocene " Flint Creek beds " near New 

Chicago. The author introduces the name Fort Logan beds for the lower part

of what had previously teen called the Deep Biver beds (Miocene of GrinneE

and Dana) and correlated by Scott with the John Day (Oligocene and Miocene) of Oregon. At several places fossil plants were found in the White 

Biver beds, and the tracks of birds and ripple marks were observed at that 

same horizon in the lower Madison Valley. Beds exposed in Townsend Vafley 

east of WInston and regarded as of White Biver age are estimated to be about 

5,000 feet thick (p. 148)1 Near Big Bound Top, in the lower Madison Valley, 

about 9 miles north (south?) of Logan, is an exposure, illustrated by Douglass's
20 GEOLOGY AND GROUND WATEB, TOWNSEND VAJJLEY, MONT.

Plate 2, showing an erosional unconformity between the " Loop Fork " and the 

"White River. The author observes that the White River beds in Montana.are 

made up of lake, marsh, and river deposits; that commonly the fiaer materials 

are distinctly stratified; that the fauna includes fresh-water diatoms, mollusks, 

and fish; and that the mammalian remains are usually fragmentary and occur 

near hills of the older rocks, which formed the shores of lakes or marshes. He 

also conceives the idea that the drainage obstructions that caused the deposition of the Tertiary beds may have been lava flows or mountain-building 

movements.

14. Douglass, Earl, The Tertiary of Montana: Carnegie Mus. Mem., vol. 2, 

pp. 203-233, pi. 22, 1905. Describes several mammals, chiefly moles, from the 

lower White River or " Titanotherium beds" at McCarty's Mountain, north 

of Dillon.

15. Douglass", Earl, Merycochoerus and a new genus of merycoidodonts: 

Carnegie Mus. Annals, vol. 4, pp. 84-98, 1907. Gives a history of the generic 

term Merycochoerus and discusses the sequence of the later Tertiary formations. Proposes the name Pronomotheriivm for a new genus, the type of which 

is the skull from clay beds near New Chicago that he had previously described 

as Merycochoerus laticeps. The " Flint Creek betis " and the " Madison Valley 

beds " are both regarded as belonging to the " Loup Fork."

16. Douglass, Earl, Some new merycoidodonts: Idem, pp. 99-109, pis. 22-30, 

1907. Describes eight species from Montana, one of which was found near 

Woodin on Divide Creek, one on Grasshopper Creek 10 miles above Bannack, 

one in a soft sandy deposit that overlies the lower White River beds at Stubb's 

old ferry on Missouri River, 11 miles northeast of Helena, and 5 at a locality 

near Canyon Ferry in Townsend Valley. Those from the Canyon Ferry 

locality (pp. 101-106, pis. 24-28) are Merycoides cursor, Hesorcvdonf latidens, 

PromerycoGhoerus hatcheri, P. grandis, and P. hollandi.

17. Douglass, Earl, Rhinoceroses from the Oligocene and Miocene deposits of 

North Dakota and Montana: Idem, pp. 256-266, pis. 63-54, 1908. Describes 

one species from the "Flint Creek beds" (upper Miocene), exposed on the 

west (east?) side of Flint Creek valley near New Chicago, and two species 

from the lower Madison Valley, one of which was found in a bed of sand 

near the bottom of the upper Miocene ("Loup Fork") exposed on the east 

side of the valley.

18. Douglass, Earl, Fossil horses from North Dakota and Montana: Idem, 

pp. 267-277, pis. 65-68, 1908. Describes five species from Montana. Of these, 

two are from the lower White River (" Titanotherium beds") on Pipestone 

Creek near Whitehall, and one from the Miocene beds exposed at Woodin on 

Divide Creek. The two remaining species were found; in Townsend Valley 

One, MerycMppusf missouriensis (p. 295, pis. 61, 67, fig. 5, and 68, figs. 1-2), 

came from the upper Miocene ("Loup Fork") beds exposed in the bluffs east 

of Missouri River, north of Confederate Creek and east of Winston; the other, 

MerycMppus msignis (pp. 275-276, pis. 67, figs. 1-2, and 68, figs. 3-5), wag 

found in Miocene deposits on Deep Creek southeast of Townsend.

19. Douglass, Earl, Some Oligocene lizards: Idem, pp. 278-285, 1908. Describes one species from the lower White River (" Titanotherium beds ") north 

of Big Hole River at the southeastern base of McCarty's Mountain, about 

15 miles north of Dillon.

SO. Douglass, Earl, Description of a new species of Procamelus from the 

upper Miocene of Montana, with notes upon Procamelvs madteonius Douglass: 

Carnegie Mus. Annals, vol. 5, pp. 159-165, pis. 9-11, 1908. The new species 

is named Procamelus elrodi. It was found in a " pinkish fine-grained stratum
TERTIARY BOOKS 21

beneath river deposits of conglomerate and sand, which are exposed in the 

bluffs on the east side of the lower Madison Valley in Montana nearly east 

of Hyde post office." Refers to* the comparative size and points out the most 

striking features in the skull of ffrocamelus madisomus, which the author had 

previously described. (See No. 9.)

21. Douglass, Earl, DromQweryx, a new genus of American ruminants: 

Idem, pp. 457-479, pis. 59-63, 1909. Proposes this name for certain of th«i 

fossil mammals previously described under the generic terni Elastomerj/x, asi 

follows: Blastortkeryss borealis Cope, B. antiloptwis Scott, and perhaps! 

Palaeomery® americanus Douglass and P. madisonius Douglass. Remains o^ 

the first two species from the upper Deep River beds between Port Logan am. 

White Sulphur Springs are described by Scott. (See No. 7.) The other two, 

described by Douglass (see No. 9), are found in the "Loup Fork" of the lower 

Madison Valley.

22. Pardee, J. T., <3oal in the Tertiary lake beds of southwestern Montana 

U. S. Geol. Survey Bull. 231, pp. 229-244, pi. 14, 1913. Gives a map showing 

the area occupied by the Tertiary lake beds in southwestern Montana west o:! 

the Continental Divide and a generalized section (p. 233) of the beds in 

the Flint Creek valley south of Dtummond. The lake beds are confined to the 

basin-like valleys. In Flint Creek valley beds that are regarded as of White 

River Oligocene age consist mainly of light-colored fine tuff or ash and clay, 

with interbedded layers of fine gravel, pure volcanic ash, limestone yielding; 

fossils of fresh-water mollusks, and shale containing plant remains. Above 

these are beds of somewhat darker shades that consists of tuff, clay, sand 

and fine gravel and are identified with the Miocene "Flint Creek beds" o:C 

Douglass. The Oligocene beds are estimated to attain a thickness of 2,100 

feet and the Miocene beds 1,000 feet or more. As a rule the beds dip gently 

trom the sides ijoward the interior of the valley. In places around the side*; 

of the valley they are considerably disturbed. The coal is found hi several 

of the valleys but apparently is limited to comparatively small areas near 

their sides. The coal beds that have been developed in the Flint Creek and 

Missoula valleys occur in the lower part of the Oligocene.

23. Jennings, O. B., Fossil plants from the beds of volcanic ash near Missoula, western Montana: Carnegie Mas. Mem, vol. 8,^ No. 2, pp. 385-427, 

pis. 22-33, 1920. Describes 23 species from collections made by Earl Douglass 

at localities north of Missoula in Missoula Valley and northeast of Winston 

in Townsend Valley. The fossiliferous beds near Missoula are interbedded 

with coal and occur about 1% miles north of the city. Their flora contains 

20 species and appears closely related to the flora of Florissant, Coio., and somewhat allied to the Mascall flora of Oregon. On the other hand, the flora 

from Missoula contains several genera in common with the floras of Yellowstone National Park; Green River, Wyoming and Utah; Bridge Creek, 

Oregon; and the Payette formation of Idaho. The author concludes that 

there is no reason why the beds of Missoula Valley should not be regarded 

as Oligocene and that the fossils might readily have been contributed to an 

Oligocene lake in a climate somewhat warmer than now prevails in that 

region, by plant associations ranging from those characteristic of wet meadows 

to those growing on rather dry rocky or sandy shores. The flora from Winston 

apparently belongs to the same general age as that from Missoula. It consists of Equigetum i/nsGidptum,, Equisetwm sp. undet., and AraMa longipetiolorta, 

(pp. 388, 398; pis. 22, flg& 1-2 j^, figs. 1-2). The Equisetwm, and Ara.Ua, both 

indicate a moist environment the one an area of shallow water, the other 

a wet meadow or moist woods. 

104142 25 4
22 GEOLOGY AND GEOUND WATER, TOWNSEITO VALLEY, MONT.

STRATIGRAPHY

Beds of moderately hardened clay and incoherent or weakJy 

cemented sand and gravel, commonly known as Tertiary lake beds, 

are exposed at many places in the ravines that cut into the benches 

and on the steep slopes or escarpments (PL'1, B) that separate the 

benches from one another and from the valley bottoms. Over most 

of the benches these beds are concealed by later gravel, though it is 

evident from the distribution and extent of their exposures that they 

extend beneath this cover and form the btdk of the material of which 

the bench lands are composed. It is probable also that they occur 

beneath the alluvium of the valley bottom and therefore extend 

throughout Townsend Valley. The Tertiary beds lie upon the upturned and eroded edges of the older rocks and in turn are partly 

covered and concealed from view by the later or Pleistocene gravel 

and the Recent alluvium. They include a lower series of Oligocene 

age and an upper series of Miocene age.

LOWEB SERIES (OLIGOCENE)

The lower series of Tertiary deposits in this area consists largely 

of moderately hardened light-colored fine claylike sediments with 

more or less fine-textured gravel or conglomerate. Apparently it 

underlies most of the valley, arid its thickness in places ranges from 

800 to 1,000 feet or more. The claylike beds consist chiefly of fine 

volcanic ash with a few layers of diatomaceous earth. In one place 

the series contains a few thin beds of coal, and in the neighborhood 

of Beaver Creek a thick lens of rather coarse-textured eruptive volcanic material. In the neighborhood of Toston the clay beds yield 

fossils of Oligocene age. The lithologic details available for this 

series are as follows:

Section of Oligocene rocks exposed 3 miles northeast of Toston, on the ridge 

north of Sixmile Creek, in sec. 12, T. 5 N., R. 2 E.

Top eroded. Feet

1. Gravel or conglomerate; red clay matrix_________- 100+

2. Clay, cream-colored to pale pink, rather soft___ ___ 80

3. Clay, pale yellow or brown, hard; contains numerous 

small branching or dendritic veinlets. of manganese 

oxides and small cylindrical concretions of clay_ 5

4. Clay, cream-colored to pale pink and pale brown, poorly

exposed__________ _________________ 200

5. Sandstone, light gray, rather soft '. , 1

6. Clay, cream-colored to pale brown 60

7. Clay, cream-colored, hard + 5

8. Clay, cream-colored to pale brown ._______ 50

9. Sandstone, light gray, rather soft \__________________ 3

10. Clay, cream-colored to pale brown - ,_ 50

11. Gravel, gray sandy matrix. 70

Spokane shale. 

624
' BOCKS

Thes strike of these beds is N. 20°~26° W., and 

NB. Bed 1 is made up of smooth pebbles from ; Shta finches in 

diameter inclosed in an abundant matrix of red <jl«y>«' Thfe* pebbles 

consist chiefly of Belt red shale (Spokane) and (jttartzite aaid 

Paleozoic limestone. These materials are cemented- together; with 

lime (calcium carbonate). Beds 2 to 10 consist mostly of volcanic 

ash or glass with a moderate amount of lime cement and here and 

there small pebbles or grains derived from the older rocks. The 

beds designated clay are composed largely of very fine glass particles that are more or less clouded with decomposition products; The 

two sandstone layers, beds 5 and 9, consist of fine-grained, waterlaid tuff or volcanic ash. They contain a few grains of the ©leter 

r<*oks and a small amount of lime cement. The pebbles in bed 11 

are from 2 to 5 inches in diameter^ are very smoothly washed, 'and 

consist mainly of quartzite, argillite, and limestone* These <and the 

pebbles in bed 1 are evidently derived from rocks that crop ^out; in 

the hills and mountains from 2 to 6 miles away on the sou$i and 

east.

The above-described beds are identified as the " Toston beds " of 

Douglass, in which he found the remains of White River (Oligocene) 

mammals, including horses, tapirs, and rhinoceroses, as, listed in 

paragraph 11, page 19.

About 2 miles southeast of the exposure just described a cut at the 

entrance of a caved adit on the south side of Sixmilfe Creek exposes 

gray and brown clays made up largely of volcanic ash and interbedded with thin layers of coal. The details of this exposure are as 

follows:

Section of Oligocene rooks exposed, in open cut south of Sixrnile Creek in,

sec. 11, T. 5 N., R. 8 E.

Top eroded. . Ft. in. 

Shale and sandstone (volcanic ash)_____________ 20+ 

Goal and clay___________________________ 6 

Clay and ash___________________________ 1 

Coal_________________________________ 6 

Clay_________________________________ 1 

Coal_________________________________ 3 

* Clay______________________________^__ I 

Coal____________________________,_1__', 8 

Clay__________________________________ 6 

Coal.:________________________________ 5 

Clay with five beds of coal from 1 to 2 inches thick I__ 2 11 

Coal______________________:_____:______ 1 9 

Clay____________ ____^___:_-,r_ -_i,_ __ , -,8> 4 ; 

Coal and clay_____,_____________^;___^_ .1 4, 

Brown clay __,_____,_____________,________ 5+ :

These beds strike N. 35°-40° W. and dip 18b-20° NE. Apparently 

they belong to the same horizon as the- section last described, the coal
24 GEOLOGY AND GBOUND WATER, TOWFSEND VALLEY, M02JTT.

being of only local extent. The coal is black and mostly of s subbitumiaous variety similar to that found in Oligocene beds in some 

of the other valleys of western Montana.9

Between the coal prospect and the mountains conglomerate is exposed here and there in the slopes or terrace escarpments on either 

side of Sixmile Creek. These beds consist of rather smoothly washed 

pebbles of limestone and other rocks, most of which are from 1 to 

4 inches in diameter, in a matrix of sand, the whole cemented rather 

firmly with calcium carbonate. Their composition indicates that 

they were derived from rocks that form the adjoining mountains on 

the east. They show dips ranging from the horizontal to 20° E., 

and their thickness is estimated to be at least 700 feet. The relation 

of these beds to the sections described is not clear, but from the 

degree of hardening and deformation they show, they are thought 

to belong to the same horizon.

In a ravine that cuts into the bench between Sixmile Creek and 

Dry Creek, from 2 to 3 miles north of the exposures described, the 

following section is shown:

fltec$on of Oligocene rocks exposed south of Dry Greek along a ravine in

sec. 36, T. 6 N., R. 2 E. 

Top eroded. Feet

1. Clay, pale pink, in alternating hard and soft layers__ 100

2. Sandstone, light gray, rather soft_____ ___ 1

3. Clay, soft, light colored_______________,___ 10

4. Sandstone like No. 2_____________________ 1

5. Clay like No. 3____________________ -___ 10

6. Sandstone like No. 2_________*.___________ 1

7. Clay, soft, cream-colored to pale brown__ ____ 80

8. Gravel or conglomerate, gray sandy matrix- ____ 10

9. Clay, soft, pale buff, with streaks of light-gray sandstone____________________________ 70

10. Gravel, gray sandy matrix___1_____ 1_ 20

11. Clay, soft, cream-colored__________________ 20

12. Clay, hard, cream-colored__________ . 5

13. Clay, soft, cream-colored________-_ 10

14. Sandstone, light gray, soft__ ________ 5

15. Clay, soft, light colored______________ 9

16. Sandstone, light gray, rather soft_____ 1 %

17. Sandstone and fine gravel in alternating layers (poorly

exposed) ___________________ _ 504- 

Bottom not exposed. : 

403

All the beds designated clay in the above section are composed 

chiefly of very fine volcanic ash. In the lighter-colored beds the glass 

particles are generally clear; in the darker beds they are more less 

cloudy or opaque with decomposition products. The harder beds con9 U. S. GeoL Survey Bull. 531, pp. 237-243, 1913.
. ; -.- TEBTIARY WJCKS : ' "^ '" 

tain a coasitteEable amount of lime. Layers 2, 6, 14, and 16f ealted 

sandstone, are composed of coarser volcanic ash-and little else ^eiofcjxt 

a few grains derived from the older rocks and a moiierttto-wnaetint

O , '

of lime cement. They appear to be water-laid tuffs. The gravel beds 

8, 10, and 17 contain very smoothly washed pebbles of quartzite an 

inch or two in diameter in an abundant matrix of sand with, little or 

no cement. The composition of the gravel layers indicates they were 

derived from the mountains 6 miles or more to the east This section 

appears to be almost exactly equivalent to that north of Sixmile 

Creek. Its gravel layers are a little finer, and it contains a somewhat 

larger amount of the coarser volcanic ash. About 5 miles farther 

north the folio wing, section is exposed in the bench lands north of 

Greyson Creek:

Section of Oligocene rocks exposed north of Greyson -Creek along east Une of

sec. IS, T. 6 N., R. 2 E. 

Top eroded. Feet

1. Clay, light brown______________________ 20

2. Sandstone, gray ___________________ 20

3. Gravel ___,__________<__________^_ 50 

, 4. Clay, soft, buff_______________________ 20

5. Gravel ___+________________________ 20

6. Clay, soft, buff______________________ 30

7. Gravel____L_______________"-_______ 10

8. Clay, soft, buff:______________________ 40

9. Shale, pale, cream-colored_________________ 10

10. Gravel____\____________________,___ 20

11. Clay, soft, buff_______________________ 30

12. Gravel___',_____________________________'______ 10

13. Mostly clay -frith a few interbedded layers of gravel

(poorly exposed). _______________ 180

14. Sandstone, Ugbt gray, rather soft ____________ 1

15. Clay, soft, ligjit buff_____________________ . 50

16. Sandstone, ligiht gray, rather soft __________ 3

17. Clay, light buff _____________________ 50

18. Sandstone, light gray________:__________ 1

19. Clay, light buff______________________ 10+ 

Bottom not exposed. _____

. 575

Here, as in the preceding sections, the clay beds are made up 

chiefly of very fine partly decomposed volcanic ash, cemented with 

small or moderate amounts of lime (calcium carbonate). The sandstone layers are composed of coarser-tenured ash with a few grains 

and pebbles of qnartzite and argillite. They show evideitces of having been assorted by ! water and are lightly cemented with lime: 

Bed 9 consists of minute silideous >skeletons of diat6ms, with, a little 

lime and glass. It is a somewhat'impure diatomaeeous eartH. 'Th4 

several gravel beds of the upper part of the section are'fine' Wf tureS,
26 GEOLOGY-AND GROUND WATER, TOWNSEND VALLEY, MONT.

well washed, and lightly cemented with, lime, and their pebWes 

consist oj rocks common to the neighboring mountains on the east-. 

In the bluffs north of Deep Creek, about 2- unites north, of the 

exposure last described, the following*beds are shdwn: « :

Section of Oligocene rocks exposed north of Deep Creek, in sec. SO, T, Y; N.,

R. 3 E. 

Top eroded. ****

1. Conglomerate or gravel with interbedded layers of

sandstone; gray sandy matrix_____-__________ 60 : ;

2. Clay, cream-colored, to buff, with sandy layers____ 40

3. Conglomerate, like No. 1_________________ 50

4. Clay, like No. 2_______________________ 30

5. Conglomerate, like No. 1_________________ 15

6. Clay, cream-colored to buff, with thin layers of conglomerate; exposures imperfect_______-__ 140

7. Clay, cream-colored to buff___________ 80+ 

Bottom not exposed. 

415

Conglomerate beds 1, 3, and 5 consist of pebbles and grains of 

quartzite, argillite, and other rocks characteristic of the mountains 

at the east, cemented with lime (calcium carbonate). Most of the 

pebbles are waterworn and less than 2 inches in diameter, but 

scattered cobbles and boulders appear here and there, the larger 

of which are as much as 1 foot in diameter. These consist of 

limestone and other rocks that appear in place on a mountain spur 

about 3 miles to the southeast. The conglomerate associated with 

clay bed 6 is uniformly fine textured. One layer is made up largely, 

of small rolled pebbles of clay similar to the clay of its associated 

beds. The clays, like those of the preceding sections, consist chiefly 

of very fine particles of volcanic glass that have become more or 

less clouded by decomposition. Most of the beds contain a considerable amount of calcium carbonate.

A comparison of the different sections so far described indicates that 

that part of the section northeast of Toston below bed 1, all of the 

section south of Dry Creek, and that part of the section north of 

Greyson Creek below bed 18 are more or less equivalent to one another, Their beds are arranged in similar sequence and are characterized by a great preponderance of light-colored clay composed' 

of volcanic ash. The thickness of this part of the section as exposed 

northeast of Toston is somewhat more than 500 feet. Bed I ofLth». 

section northeast of Toston, beds 1 to 12 of the section north of 

son Creek, and beds 1 to & of the section north of Deep Creek 

wise form a correlated series occupying a higher position 

aqterized by a rather large amount of gravel,or conglomerate. .,,&$ 

 exposed in the section north of Greysoa Creek the .thickness- ol->ibi&
. ; ; TEBTXARY BOCKS , . 27

upper part is nearly SjJOO f«et, which added to the tMekness obtained 

for the lower part gives .800 feet as the! total minimum thickness of 

the Qligoeeae beds eixposed in the southeastern part of Towasead 

Valley. '

In the bluffs along Beaver Creek and the adjacent part.ol Missouri Kiver, about 1^ miles northwest of the section last described, 

are extensive exposures of Oligocene beds of which the following is a 

generalized description:

Section of Oligocene rocJts exposed along Beaver Creek from 1* to 3 miles northeast of Winston, in the southeastern part of T. 9 N., R. IE.

Top eroded. Feet

1. Volcanic ash or tuff; light gray to pale yellow With several dark-graiy and brown layers; two thin layers of 

diatomaceousi earth in, the lower part____ __ 800

2. Volcanic conglomerate.; coarse bouldery gravel interbedded and fiaixed with gray, brown, and olive-green 

tuffs____I_________________________ 1,200

3. Volcanic ash or tuff, chiefly light gray; exposures imperfect; thickness estimated____________1__ 700

4. Clay, pate yellow or buff, exposures imperfect; thickness

estimated___________________________ 100

2,800

The beds strike N. koo-^0° W., dip from the horizontal to 30° NE., 

and rest unconformably upon andesite and quartzite.

This section differ^ strikingly from the others in Townsend Valley in its unusual thickness, which is due to the presence of a great 

mass of tuff and volcanic conglomerate that do not appear elsewhere. Bed 1 consists mostly of moderately fine volcanic ash with 

a few layers made up of coarser fragments of porous glass and 

denser lava. The layers of diatomaceous earth consist of very 

minute skeletons of siliceous diatoms. One layer is white and practically unmixed with other materials; the other is pale brown and 

contains a little glas£ and. a few plant remains and shells of freshwater snails. The votcanic conglomerate, bed 2, is indistinctly stratified, and most of it apparently came to place like a flow of mud or 

wet earth. Its cobbles and boulders are more or less angular, range 

from a few inches to 3 feet or more in diameter, and consist chiefly 

of andesitic lava, with a little quartzite. The matrix appears to be 

a tuff. It readily weathers to a product that when dry is a loose 

mealy powder and when wet an excessively soft and slippery mud. 

Probably it is made Up partly of bentonite, a variety of clay having 

the property of absorbing much water and swelling to many times 

its original bulk. Bed 4 consists of very fine, partly decomposed 

fragments of volcanic, glass like s those that form the bulk of fh,e 

light-colored clays i& the other sections described.
28 GEOLOGY AND GROUND WATER, TOWNSEND VALLEY, MONT.

Along the bluffs east of Lake Sewell, between Beaver Creek and 

Canyon Ferry, light-colored clay consisting mostly of .fine partly 

clouded volcanic glass cemented with lime crops out in many places. 

These beds attain a thickness of at least 150 feet and appear to lie 

stratigraphically above the uppermost beds of the Beaver Creek 

section. At several places in the distance of a mile, extending northeast from a point a quarter of a mile east of the Canyon Ferry dam, 

light-colored clays are exposed that dip 10Q -16° NE. At the beginning of this series of outcrops east of the dam a natural exposure 

shows the Tertiary beds resting upon granodiorite, a member of 

the older rock group. The two formations are separated by a few 

feet of greenish-gray material consisting of angular grains and 

fragments of the granodiorite embedded in a claylike matrix, the 

whole evidently an old soil or surface mantle produced by weathering of the granodiorite before the Tertiary beds were deposited. 

Both the old surface and the overlying Tertiary beds dip 15° NE., 

and the total thickness of the Tertiary in this section is estimated at 

1,000 feet. Along Cave Creek northeast of Canyon Ferry gravel 

or conglomerate is exposed that consists chiefly oi grains and pebbles 

of red and gray argillite and quartzite in an abundant matrix of 

lime (calcium carbonate). Most of the rock fragments are angular 

and less than 2 inches in their greatest dimension and evidently were 

derived from Belt (Spokane) shale and other rocks that form the 

adjoining mountains. The different exposures show that the conglomerate gradually takes the place of clay beds as the mountains 

are approached and is equivalent to the upper part of the Canyon 

Ferry section. Near the foot of the mountains a bed of light-gray 

tuff similar to some of the tuffs in beds 1 and 3 of the Beaver Creek 

section lies upon a surface cut across the older rocks. Above the 

tuff is conglomerate. Apparently the tuff overlaps the lower beds 

of the Tertiary section and is in turn overlapped by the conglomerate. The dip of the surface on which the tuff beds lie is about 25° 

SW., and the tuff and the overlying conglomerate dip 15°-20° SW. 

The total thickness of the Tertiary beds in this locality is estimated 

to be not more than 500 feet.

Except for the volcanic conglomerate and tuff exposed at Beaver 

Creek, which apparently form a lens of local extent, the beds in the 

foregoing sections are similar in appearance and composition to 

those in the southeastern part of the valley determined as Oligocene 

and are therefore correlated with them.

In the middle and southwestern parts of Townsend Valley beds 

that presumably are to be correlated with those described above 

appear here and there but form no very extensive exposures. In this 

categ6ry are beds of pale-yellow or buff clay exposed at the east side
TERTIARY ROCKS 29s

of the valley betwebn Gurnett Creek and Kay Creek that rest on an 

eroded surface of the older rocks and are themselves overlain by 

sand and gravel of local derivation; the thickness of the whole series 

is less than 100 feet. These beds and the surface beneath dip gently 

southwestward, or toward the axis of the valley. Half a mile out in* 

the valley the beds dip 7° in the opposite direction, or toward themountains. On the west side of the valley, in the bluffs facing the 

river 3 miles soutlk of Beaver Creek, 4ft or 50 feet of the lightcolored clay appears. The beds dip 10° or less toward the northwest and are overlain unconformably by later gravel. Opposite 

Townsend are a few very small exposures of similar clay. West and 

south of Kadersburg clay is exposed over a considerable area from 

which the overlying alluvium has been stripped by placer mining. 

Here it rests upon a somewhat uneven surface of andesite and varies 

in attitude from thfi horizontal to a dip of 5° E.

UPPER SERIES (MIOCENE)

The upper or Miocene series of Tertiary beds of this area is 

poorly exposed. Apparently it lies in valleys eroded in the lower 

(Oligocene) series 'and is of less extent than that series. It occupies 

a small area south of Deep Creek and a comparatively large one 

north of Confederate Creek and probably extends over part of the 

bench land and area on the west side of the valley south of Winston. 

The series attains 'a thickness of at least 500 feet and consists chiefly 

of incoherent sand and gravel derived from the older rocks that 

compose the neighboring mountains. Presumably it yielded the 

Miocene fossils listed in paragraphs 16 and 18, page 20,

The best exposures observed of the Miocene beds occur a short 

distance south of Deep Creek in a ravine known as Dry Gulch, in 

sees. 11 and 14, T. 6 N., K. 2 E. Here most of the beds consist of 

light-brown to buff incoherent sand and gr&vel; a' few contain more 

or less clay and are lightly cemented with calcium carbonate. Some 

of them exhibit the cross-bedding characteristic of sediments deposited by streams in slack water. In places the gravel contains 

cobbles or boulders as large as 1 foot in diameter, but most of it is 

fine textured. Thei cobbles land pebbles are more or less angular 

and consist chiefly of quartzite, limestone, and other rocks common 

in the mountains about 4 miles away on the east. The beds dip 8°- 

12° SW., and their total estimated thickness is between 500 and 700* 

feet. A short distance east of this area beds typical of the lower orOligocene series appear, and their attitude strongly suggests ant 

angular discordance or difference in dip of 4° to 8° or more betweeni 

them and the upper series.

The remains of a Miocene horse (Merychippus insignia, referred! 

to in paragraph 18^ p. 20), described by Douglass as having come* 

104142 25 5
30 GEOLOGY AND GROUND WATER, TOWNSEND VALLEY, MONT.

from deposits on Deep Creek southeast of Townsend, are assumed 

to have been found in this upper series of Tertiary beds and probably within or near the area here considered.

In the bench lands north of Confederate Creek are several small 

exposures that apparently belong to the Miocene series of Tertiary 

beds. One of these, in a ravine half a mile southeast of Brown's 

ranch, in sec. 27, T. 10 N., R. 1 E., shows, beneath a thin layer of 

later gravel, about 10 feet of fine pale-yellow sand that tends to 

stand in vertical faces. Below the sand is 10 feet or more of finetextured gravel composed of flat pebbles of Belt rocks in a rather 

firm and dense matrix of clay and fine sand. The bedding is nearly 

horizontal. In the bluffs east of Missouri River, at the county bridge 

south of Beaver Creek, is exposed 50 feet or more of lightly cemented, 

rather fine gravel that consists of smoothly washed pebbles in an 

abundant light-colored dense matrix of sandy clay. The remains 

of a Miocene horse (Merychippus missouriensis, referred to in paragraph 18, page 20) described by Douglass as having come from the 

bluffs east of Missouri River north of Confederate Creek and east 

of Winston were probably found in these beds or in beds associated 

with them. On the bench west of Cave Creek, about three-quarters 

of a mile north of Canyon Ferry, placer-mining excavations expose 

beneath the gold-bearing bench gravel 40 feet or more of loose or 

incoherent sand and fine gravel. The composition of these beds indicates that they were derived from the mountains at the northeast. 

They lie nearly horizontal, and their altitude is less than that of 

some of the beds of the lower series exposed in neighboring areas 

facts which indicate them to be in a valley eroded in the lower series 

after it had been slightly tilted. The remains of several species of 

Miocene mammals (see par. 16, p. 20), described by Douglass as 

coming from Canyon Ferry, are presumed to have been found in 

these or similar beds near by.

In the bluffs west of the river, 2 or 3 miles south of Beaver Creek, 

near Hahn's ranch, is exposed 30 to 40 feet of rather fine horizontally bedded gravel with streaks and lenses of sand and clay. 

The deposit lies unconformably upon light-colored clay beds of the 

lower series and appears to form the lower end of a group of coalescing alluvial fans that, in this part of the valley, cover most of the 

bench-land area. Whether it is to be correlated with the Miocene or 

the still later Pleistocene deposits is not clear. Possibly it is 

equivalent to parts of both.

STRUCTURE

When newly deposited the beds of clay and other fine sediments 

must have lain horizontal or nearly so. Possibly the layers of 

stream-deposited gravel had a slight inclination, and the coarser
t TERTIARY ROOKS 31

 volcanic products ini the Beaver Creek section may have assumed a 

'Considerable dip. In general, however, the beds are regarded as 

having been essentially flat-lying at first, their present attitude, 

which commonly departs 20° or more from the horizontal, being the 

result of subsequent movements within the crust of the earth. The

 outstanding structural features are a zone of anticlines that extends 

northwestward across the valley from the neighborhood of Toston 

to the Spokane Hills and a monocline or persistent dip toward the 

: northeast shown over most of the area east of this zone. Less promi- 

:nent features include small synclines and steplike faults that, locally 

;at least, cause the outcrops of the different beds to be repeated.

FOLDS

From a point south of Dry Creek in sec. 30, T. 6 N., R. 3 E., an 

^anticline may be traced northwestward to the bench north of Deep

 Creek in sees. 35 and 36, T. 7 N., K. 2 E., a distance of about 6 miles.

.Dips on its east side range from 10° to 20° and on its west side 

from 8° to 15° (fig. 3). Along its axis the light-colored clays of

;the lower or Oligocene series appear, and at a considerable distance

rto the east these give place to conglomerate. The beds forming the 

west side of the anticline are generally concealed from view. Along 

Dry Gulch south of Deep Creek they belong to the upper or Miocene

 series, as described on page 29. South of Dry Creek the anticline

 ends in an area occupied by several small folds that rise toward the 

south and disappear in that direction. North of Deep Creek it is

 concealed by gravel and other alluvium younger than the Tertiary. 

About 2 miles north of Winston an exposure of horizontal beds of 

buff clay belonging to the lower series or Oligocene appears to mark 

the crest of another northwestward-trending anticline. On the

 eastern flank of thi$ fold the dip, as shown by numerous exposures 

in the bluffs west of Missouri Kiver, is 15°-25° NE. The beds forming its west side are generally concealed, but an exposure about 8 

miles northwest of 'Winston shows a dip of 15°-20° SW. This fold 

and the Deep Creel$ anticline have about the same trend, and their 

axes are nearly in line. Both are included in a rather narrow zone 

extending northwestwar4 across the valley from Sixmile Creek to 

the Spokane Hills. Between these two areas is a space of 15 miles 

or more, forming a middle section of the zone in which the Tertiary 

beds are concealed. However, the attitude of beds exposed to the

 east of this section indicates that the anticlinal structure probably

persists throughout the zone. '

Throughout most of Townsend Valley east of the zone described

the lower series of Ijertiary beds shows a persistent eastward dip that 

:ranges from 10° to 20°. As a rule, no change from this attitude is
32 GEOLOGY AND GROUND WATEB, TOWNSEND VALUEY, MONT.

apparent to a point within a mile or two of the mountains. Beyond 

this point, however, the beds gradually decrease in dip, become horizontal, and in places incline in the opposite direction. Along Cave 

Creek and Magpie Creek at the foot of the mountains the beds dip 

20° or more toward the valley (fig. 5). Half a mile below they become horizontal, and a little farther on they assume the usual dip 

to the northeast. The trough or syncline thus shown trends nearly 

east and extends for a distance of at least 3 or 4 miles. At the edge 

of the valley east of Canton a similar small syncline is indicated, 

but on Sixmile Creek the Tertiary beds dip eastward near the foot 

of the mountains and are in fault contact with the older rocks..

West of the anticlinal zone the attitude of the beds is indicated only 

at Radersburg, at the western edge of the valley, where the dip is 

gently eastward. Presumably the beds are bent into a shallow

syncline.

FAULTS

Faults that cut and displace the Tertiary beds appear in the section exposed northeast of Toston (fig. 4). Here a fault is shown 

that strikes N. 30° E., dips 45° W., and cuts through layers of gravel 

and light-colored clay belonging to the Oligocene. Its walls are 

smooth and regular, being separated by only an inch or even less of 

gouge. The western or hanging wall has fallen at least 40 feet, 

bringing a bed of gravel opposite one of clay. In the adjoining area 

repeated outcrops of the same beds together with sudden changes in 

the dip make certain the presence of at least four faults within the 

distance of a quarter of a mile. Apparently the faults strike northwestward and dip steeply to the southwest, and their west or hanging walls have dropped relatively. The displacement on each fault 

ranges from 50 to 150 feet or more and on all aggregates at least 350< 

feet. One effect of this faulting is to reduce the apparent thickness 

of the Tertiary beds.

At the point where Sixmile Creek leaves the mountains Tertiary 

beds that dip 20° E. abut against the older rocks. The boundary between the two is a fault (fig. 3) that strikes north and has caused a 

relative downward displacement of the block on the west or valleyward side.

Elsewhere within the valley no definite evidence of faulting was 

obtained, but it is considered probable that step faults like those 

northeast of Toston occur in other areas. East of the anticlinal zone 

the thickness of the Tertiary beds, as indicated by the persistent dip 

in one direction, is excessive. For example, in the bench north of 

Deep Creek a northeastward dip of 15° is shown for a distance of 6 

miles or more. Therefore, unless the effect of this'dip is offset by 

faulting or some other unsuspected structural feature, the beds must
TERTIAKY ROOKS 33

be assumed to attam the improbable thickness of 7,000 or 8,000 feet 

and.fill ftstreneh or basin of equally improbable depth. Int the west* 

era part of the valley south of Winston a northwestwtord*tr©ndin^ 

fault is possibly indicated by a line of springs.

AGE AND CORRELATION

i

The lower or Oligocene series of Tertiary beds in Townsend Val* 

ley is similar in Appearance and composition to the beds in the 

neighboring basin-like valleys of the mountainous region of western 

Montana regarded i as of Oligocene (White River) age and is apparently their general equivalent in time. It includes the fossiliferous beds near Tosron which are regarded by Douglass10 as corresponding in part tb both the lower or Titanotherium zone and the 

middle or Oreodori zone of the White River. In the other valleys 

beds belonging to the Titanotherium zone have been identified, as 

described in the reports listed on pages 19-20 (Nos. 11-14), at Thompson Creek northwest of Three Forks, at Pipestone Creek near WTiitehall, and east of IjtcCarty's Mountain, north of Dillon. Beds determined with more or less certainty as White River without indicating the subdivisions to which they may belong occur in lower 

Madison Valley south of Three Forks, in Beaverhead Valley on 

Blacktail Creek southeast of Dillon, in Blackfoot Valley near Helmville, in Flint Cre^k valley southwest of Drummond, and in Missoula Valley north of Missoula:

The correlation pf the beds under consideration with the White 

River formation oil Nebraska and South Dakota has been indicated. 

In addition they correspond closely with the Oligocene deposits of 

the Cypress Hills ito southwestern Saskatchewan, Canada., The Cypress Hills deposits attain a thickness of 5000* feet at the east 

and consist of conglomerate, usually formed of quartzite pebbles 

cemented together with carbonate of lime, associated with beds of 

sandstone, sand, cl^ny, and marl.11 Fossils found in these beds consist of more than 50 vertebrate species, including fishes, reptiles, and 

mammals, of whidhj the mammals preponderate in numbers and variety. Among them are Titanotherium, rhinoceroses, oreodonts, 

horses, dogs, rodeiits, and a cat. These deposits are regarded by 

Matthew12 as probably of about the same age as the " Titanotherium

beds" at Pipestone Springs, Mont., $nd by Lambe13 as belonging, in

a general sense, to liie Titanotheriwm zone of Montana, though some 

of their upper members may be synchronous with the Oreodon zone.

10 Douglas*?, Earl, Am. 

"Lambe, L. M., The 

Contr. Canadian PaleontoljOgy, 

12 Matthew, W. D., Am, 

w Lambe, L. M., op. d

Soc. Trans., Hew ser., vol. 20, p. 243, 1902.

vrtebrata of the Oligocene of the Cypress Hills, Saskatchewan j 

, Vol. 3, pt. 4, p. 5, 1908-. 

. Nat/Hist. Ball;, vol. 19, p. 202, 1903.

 t, p. 8.
34 GEOLOGY AND GROUNfr WATER, TOWNSEND VALLEY, MONT.

/

The upper or Miocene series of Tertiary beds in Townsend Valley 

bears a strong resemblance in compositionj occurrence, and. .ojbher 

features to the " upper beds " in the neighboring Smith River (Deep 

River) valley as described by Scott.14 The fauna from Townsend 

Valley is referred by Douglass to the middle or upper Miocene and 

that from Smith River valley is regarded by Scott to mark a distinct horizon at the base of the " Loup Fork." Compared with those 

in Townsend and Smith River valleys the "Loup Fork beds" in 

most of the other valleys differ noticeably in appearance and composition, owing to the fact that they generally contain a large 

amount of clay or volcanic ash. Whether these differences mean 

that the beds represent more than one horizon apparently has not 

been determined. Miocene fossils have been found most plentifully 

in lower Madison Valley near Hyde post office and in Flint Creek 

valley n^ar New Chicago, and the beds are regarded as generally 

corresponding in time to the Miocene beds of Nebraska and neighboring regions. Parts of them may prove to be equivalent to the 

Flaxville gravel in northeastern Montana, described by Collier and 

Thorn.15

The " lower beds " in Smith River valley are correlated by Scott 16 

with the summit (lower Miocene) of the John Day formation of Oregon and therefore appear to be rather widely separated in age from 

the lower series (Oligocene) in Townsend Valley.

Concerning the differences between the Tertiary fauna of the 

mountain province and that of Nebraska and neighboring parts of 

the Great Plains, Douglass " observes that the evidence thus far obtained seems to show either that the two regions during Oliogicene 

and Miocene time were faunally distinct or that the preservation 

of mammalian remains seldom, if ever, exactly coincided in time in 

the two areas.

QTJATEBNABY DEPOSITS

Townsend Valley is Overspread generally witti. a layer of loose 

or unconsolidated gravel, sand, and silt that was deposited by streams 

upon surfaces eroded across the deformed Tertiary and older rocks. 

Most of the deposits on the two higher benches, which evidently are 

older than those at lower levels, are described herein as bench gravel. 

The deposits that underlie the valley bottoms and bench No. S form 

a younger group called valley gravel. Associated with both groups 

are a few deposits classified as of glacial origin. Except the soil

u Scott, W. B., Am. Phlloa Soc. Trans., new ser., vol. 18,. p 58, 1895. 

M Collier, A. 3., and Thorn, W. T., jr., TJ. S. Geol. Survey Prof Paper 108, pp. 179-184, 

1918. . , , 

*> Scott, W. B., Am. Philoa Soc. Trans., vol. 18, p, 59, 1895. 

» Douglass, Earl, Carnegie Mus. Annals, vol. 4, p, 268, 1908.
QtTATERNABY DEPOSITS'

that forms the present surface, deposits younger 

.are of comparatively small extent. They inelwi te 

viran on the- valley i>ottoms and on the benches 

and wind-blown sand that occupies a small area so»th of

than the Pleistocene 

some of the aUu* 

the mountains 

Crow Creek;

next to

.BENCH GBAVEL

this

Creek

On the higher beltches north of Deep Creek a 

10 to 20 feet thick is exposed near the mountain; 

rough and moderately waterworn boulders thai 

feet in average diameter, and its matrix is an 

It lies on a surface of erosion that cuts across th 

rocks, and the pebb us it contains are of the 

that crop out in the g.djoining mountains. Away 

the gravel becomes thinner and finer textured. 

gravel is exposed on the be,nch south of Confed 

point at which the »tream lea'ves the mountains 

hood of Diamond City, several miles above 

lies on narrow benches bordering Confederate 

sively mined for gold. The benches apparently 

with Nos. 1 and 2 of Townsend Valley. The 

dently deposited by a stream, is not as a rule hi 

except for the presence of a few large boulders, 

It consists mainly oi quartzitic rocks similar to 

Belt formation of ihe surrounding area. In 

mouth of Boulder Creek this gravel is overlain 

gravel that is barren of gold and is made uj 

material. This .gravel is much fresher looking 

presumably belongs to the younger valley grave

For a considerable distance north of Confederate 

of the bench lands is thinly overspread with 

ently was brought out from the adjoining mount 

recent time. Probably the most of it is to bo 

bench gravel. Neaf the north end of the vall< 

and Cave Creek, th«! bench gravel has been mined 

a rule, it is of moderately coarse texture, moderately 

as elsewhere, made, jp of materials derived froir 

by. The gravel adjacent to Cave Creek, however, 

by the presence^of i usually large boulders

for a distance of a mile or more out from the feot

These boulders am 

and range froms 4 t

rough or subangular, consist 

8 or liO feet in. average diameter,

incloses them. that

so much out of agreement wit^i the general texture,of

,«oulA hardly have*been

ayer of gravel from 

It contains many 

range from 1 to 3 

abundant sandy clay. 

»^Tertiary and older 

e kinds as the rocks 

from the mountains 

Somewhat similar 

rate Creek near the 

In the neighborpoint, gravel that 

has been extenare to be correlated 

gravel, though evifhly waterworn nor, 

rery coarse textured, 

hose common, in the, 

i low bench at the 

>y a coarse-textured 

chiefly of granitic 

than the other and

Creek the surface 

alluvium that apparinsin comparatively 

.classified with tjie 

^,jOn Magpie Creek 

for gold. Here^ as 

waterwora, and, 

mountains near 

is distinguished 

distributed here and there 

of the mountains, 

mainly of quartssite, 

Their .size is 

the.gravel that 

transported, and. $e-
36 GEOLOGY AND GROUND WATER, TOWNSEND VAIJUEY, MONT.

posited by the same stream. Probably they were carried out from, 

the mountains by some unusual flood or by a glacier, and in that 

event they composed part of a deposit that was afterward reworked 

by streams into the gold-bearing gravel described.

In the western part of the valley rather coarse gravel is exposed 

by placer-mining excavations on the benches north of Indian Creek 

and west and south of Radersburg. It is composed of materials 

carried out from the adjacent mountains and otherwise is like the 

bench gravel described. South of Winston th^ bench lands are 

covered with a sheet of gravel composed of extensive coalescing fans 

deposited by ephemeral streams from the adjoining mountains. 

Probably the upper part of this sheet is made up c[f bench gravel and 

later deposits. ;

The bench gravel was deposited after the Tertiary beds had been, 

deformed and eroded and therefore is consideribly younger than 

Miocene. Because of its close association with a relatively old glacial 

moraine described on the following pages, it is Regarded as chiefly 

of early Pleistocene age.

VALLEY GRAVEL

The valley bottoms and the lowest or No. 3 bench are composed of 

gravel derived from a number of sources, including the bench gravel, 

the Tertiary beds, and the older rocks of the mountains. In general 

this gravel is very open textured and much more loose or incoherent 

than the bench gravel. Along the middle part of the valley it is 

rather fine textured and smoothly waterworn; toward the mountains 

it becomes coarser and more angular. As exposed in a road cut in 

No. 3 bench about a mile east of Townsend this formation consists 

of smoothly washed pebbles and cobbles of quartzite and other re-< 

sistant rocks in a loose and open sandy matrix. In places it is 

lightly cemented with calcium carbonate; elsewhere it falls apart 

freely. Similar material is exposed by wells in most of the lowlands 

adjacent to Missouri River, where its minimum depth is from 20 

to 40 feet. Probably its total thickness is considerably greater.

Toward the mountains this gravel becomes coarser, though along 

several pf the streams, including Deep Creek and Greyson Creek, it 

decreases in thickness and within the mountains is as a rule of comparatively small bulk. Along Confederate Creek, however, a rather 

thick sheet of coarse gravet extends 5 or 6 miles within the mountains 

to Boulder Creek and thence continues up that stream. Unusually 

thick and coarse bouldery gravel occurs also along Beaver and 

Crow creeks for considerable distances above and below the'points 

at which they issue from tne mountains. ;

In areas whei?e few or no permanent 1 streams crosg >the'bench 

lands alluvial cones and fans deposited by short-lived streams are
' QUATERNABY DEPOSITS , 87

spread out for considerable distances from the mountains, In the 

stretch of 10 or 12 miles between Indian Creek and Winston fans 

of this kind cover practically all the bench lands to a considerable 

"but unknown depth. An incomplete section of this formation exposed in the bluff west of Missouri River about 3 miles south of 

Beaver Creek, described on page 80, shows 30 feet or more of rather 

fine stratified subangular gravel containing streaks and lenses of 

«and and clay. The beds dip about 3° E., or practically the same as 

the slope of the surface. Toward the mountains the gravel becomes

 coarser and thicker, and the fragments more angular. Apparently 

it has been accumulating without interruption for a long time and 

probably is equivalent in age to parts of the upper or Miocene series 

of Tertiary beds, the bench gravel, and the valley gravel. North

 of Confederate Creek and in places elsewhere small gravel cones 

or fans, corresponding in age with the valley gravel, occur on bench: 

ISo. 1 where it adjoins the mountains.

Because it includes outwash from glaciers of a late stage the valley 

gravel is thought to be late Pleistocene. Gravel that evidently is of 

Eecent age includes a few small areas of alluvium and wind-blown 

«and.

GLACIAL DEPOSITS

Near Smith's ranch, at the foot of Mount Baldy, in sec. 13, T. 

8 N., E. 3 E., a small moraine lies on top of bench, No. 1. It forms a 

^semicircular ridge about half a mile long and 50 feet high that shows 

the uneven topography, unassorted rock d&bris, and large boulders

 characteristic of glacial material. The exposed material appears

 considerably weathered, and no striated surfaces were seen. At the 

wack or east of the deposit a small valley extends jiart way up Mount 

Baldy. At the north and south are longer valleys, occupied respectively by branches of Gurnett and Ray creeks that are cut well 

oelow the bench level. If at the present time a glacier should form 

on the upper slope of Mount Baldy, it would flow down either of 

these valleys rather than the one leading to the moraine. Therefore 

it is concluded that the moraine was deposited at an early stage of 

glaciation, before the deeper valleys were cut. Though no direct

 evidence of glaciation was found in the neighborhood of Cave Creek, 

the unusually large boulders in the bench gravel adjacent to that 

stream suggest the possibility of glaciation at a similar early stage. 

The mountains surrounding Townsend Valley have not been examined in detail, but it is evident from distant views and available 

maps 18 that they contain several cirques from which at a late stage

 small glaciers may have descended for moderate distances. Glaciers

18 XI. S. Cteol. Survey topographic inap of FoiJ; Logan quadrangle, 1914; IT. S. General 

JLand Office plat of T. 9 N., R. 3 E. Montana meridian. :
38 GEOIX)GY AND GROUND WATER, TOWNSEND VALLEY. MONT. 4 

of this type are indicated to have existed at the heads of Boulder 

Creek, Crow Creek, and Beaver Creekr and the unusually coarse <and 

bulky gravel along the lower courses of these streams is thought tobe chiefly outwash of the late stage.

I

PHYSIOGRAPHY

Townsend Valley and the adjoining mountains have been fashioned from an ancient surface, part of which is yet preserved beneath the Tertiary sediments.

As described on page 28, the Oligocene beds lie upon a surfacethat cuts across strongly deformed rocks of the older group, which 

range in age from Cretaceous to pre-Cambrian. Hear the Canyon 

Ferry dam and at a few other places natural exposures show that 

this old surface, though somewhat uneven, is without sufficient relief 

to class it as mountainous. The line that separates the Oligocene 

and older rocks around the margin of Townsend Valley is nearly 

everywhere the trace of this old surface where it meets the present 

one. This trace shows some broad curves where it passes around 

projecting mountain spurs, but in most places its course is free from 

crooks or indentations such as it would show if the old surface were 

roughened by hills and valleys of sharp or considerable relief. Evidently the old surface is the product of erosion that continued for a 

long time without interruption. It was cut across a variety of 

rocks, from which an aggregate thickness of several thousand feet 

must have been removed. The youngest of the eroded rocks aremiddle or perhaps late Cretaceous. Therefore, so far as the records 

in Townsend Valley show, all of Eocene time, at least, was available 

for this work, including the preliminary folding and elevation of 

the rocks.

The present general form of the old surface is like that of a dish 

or shallow bowl. At all its exposures around the margin of the 

valley it dips toward the interior. Thus near Canyon Ferry, at 

the northwest side of the valley, the dip is about 15° E. (fig. 5). 

At Cave Creek, on the opposite or northeast side, the dip is 20°-25° 

SW. At the east along the middle strech of the valley the dip is 

about 12° W., and in the southwestern part, south of Kadersburg^ 

the old surface dips 5° or more toward the northeast. If these dipsare projected inward and decreased somewhat as tliey approach one 

another they carry the old surface to a depth of 2,000 feet or more 

in the central part of the valley (figs. 4 and 5). There appears to 

be no deep channel leading away from this basin through which it 

could have been drained, and its hollow or dishlike form is therefore thought to be the result either of downwarping or depression 

of this particular part of the earth's surface or an upward move-
 ' ' PHYSIOGRAPHY 3f

ment of the surrounding lands. The truth of thistsapposition is 

indicatedHby the fact that the overlying Oligocene beds now dip inward around the margin of the valley, the same as the old surface, 

except that in places their inclination is somewhat less. Evidently 

the Oligocene beds, Vhieh were horizonal when.they were deposited, 

and the old surface iaave been depressed or otherwise deformed together. Additional evidence that the old surface has been deformed 

by structural movements is afforded by an exposure along Sixmile 

Creek near the foot of the mountains. Here a fault, described on 

page 32, eu$s both tke old surface and the overlying Tertiary beds, 

causing them to be dropped on the west or valleyward side or elevated on the other side (fig. 3). It is probable that in the interior 

of the basin the old jsUrface has been deformed in the same manner 

as the Oligocene beds. Doubtless the small step faults northeast of 

Toston dislocate it, a; ad there is reason to think that in the anticlinal 

zone that extends from Sixmile Creek northwestward to the Spokane Hills the old surface is arched or otherwise elevated the same 

as the overlying bedg. In fact, definite proof of this appears to be 

given by the section exposed across the Spokane Hills from Canyon 

Ferry to Prickly Pear Valley (fig. 5). On the east side of the hills 

both the old surface and the overlying beds dip eastward. On the 

west side the beds dip westward toward Prickly Pear Valley and, 

though the old surface is not here directly exposed, its trace along 

the foot of the hills near, by indicates a similar dip. Thus the Spokane Hills appear to be an arched portion of the old surface from 

which the overlying Oligocene beds have been worn away.

If the irregularities described as caused by structural movements 

were smoothed out .and, the Tertiary beds removed, or, in other 

words, if the conditions at the beginning of Oligocene time were 

restored, the old surface would appear as a wide lowland surface 

sloping gently upward along the east, where now is the foot of the 

Belt Mountains. Doubtless it would show a similar upward slope 

along the west, at uhe 'foot of the present Elkhorn Eange. The 

Spokane Hills and the ridge that now bounds the valley on the 

southwest would not be tin vusw, and the low surface would extend 

without mterruptioiL into Prickly Pear Valley on one hand an4 

Madison-Gallatin VjJley on the other, but the conical hill south of 

Kadersburg known as Lone Mountain, the small ragged granite 

ridge southeast of Warafr Spring Creek^ and part of the hills southwest of TostoB were in existence.

Beneath the Tertiary beds of the other basin-like valleys of 

western Montana arn old surfaces that ase similar to that in Townsend Valley and ar<r thought to be generally courelatable with it: 

The information so farj available suggests that most if not all of 

these valleys were preceded in Oligocene time by lowlands like the
40 GEOLOGY AND GROUND WATER, TOWNSEND VALLEY, MONT.

old surface beneath Townsend Valley, and that these lowlands were 

originally continuous with one another but later, aS a result of earth 

movements, became more or less definitely separated into parts, as at 

present. Presumably the Oligocene lowlands were bordered by 

mountains that occupied essentially the same positions as the principal ranges of to-day. An elevated area along the east of Townsend Valley corresponding to the present Belt Mountains is indicated by the fact that before the post-Oligoeene folding the old 

surface rose in that direction. Later on, when sediments were accumulating on the oH surface, gravel was washed in from the east, 

giving further indication of the existence of high land. Similar 

evidence elsewhere indicates that the Oligocene lowlands were bordered by mountains. Little information tending to reveal the contour of these ancient mountains is available. Because no coarse 

gravel was carried into the lowlands it is thought that the Oligocene 

streams had low gradients, which in turn, may be regarded as evidence that the mountains had become well dissected and worn down 

to a moderate height.

While the lowlands and mountains described were being carved, 

the region had free and unobstructed drainage. $o deposits representing this period of erosion are known within the region. Apparently the streams were able to carry all the products of .erosion far 

beyond its borders. In Oligocene time, however, conditions changed 

so greatly that sediments began to accumulate on the hitherto cleanly 

swept lowlands. The deposition may have been the result of a 

change from a moist to an arid or desert-like climate such as would 

cause the streams to become intermittent and therefore un&ble to 

remove the sediments from the valleys as fast as they brought them 

in, or the deposits may have been caused by obstructions to the 

drainage, either lava flows or barriers elevated by structural movements. Whatever the true explanation, it is evident th'at the sedimentation began and continued without interruption until 1,000 

feet or more of beds had accumulated in the central parts of the 

valleys. The features of these beds, as previously described, show 

that during the time they were accumulating the valleys contained 

alternately ponds, marshes, and areas of dry land on which lived 

strange species of lizards, rodents, camels, rhinoceroses, and other 

animals. When the Oligocene beds had attained their maximum 

thickness they overspread the valleys completely *and lapped up on 

the flanks of the mountains, though there is no evidence that they 

ever submerged the mountains completely or covered the region 

generally as a blanket. On the contrary, there is much gravel in 

the upper part of the beds that evidently was derived from the
PHYSIOGRAPHY , 41

erosion of the mountains, which therefore must have remained well 

above the areia of deposition.

One of the most significant features of the Oligocene beds is the 

large amount of volcanic ash or tuff they contain. Most of this 

material is as fine grained 'as silt or clay and doubtless was brought 

from a distance suspended in the air. Part of the deposit in Town<- 

send Valley, however, is coarser and came from a local volcano 

situated apparently near Winston. Some of the beds consist of 

pure or unmixed ash that remains as it fell. The others are mixed 

with sand or pebbles and are thought to represent material that fell 

upon the surrounding elevated or mountainous areas and was later 

washed into the basins.

It is significant as indicating a basin surrounded by highlands 

that fine materials like clay are more abundant in the central parts 

of the valleys and relatively coarse materials such as gravel are 

more plentiful around the sides. At this time, while the drainage 

was generally obstructed in southwestern Montana, a vigorous stream 

was transporting gravel from the mountains in the region of Glacier 

National Park eastward to the Cypress Hills, a distance of nearly 

200 miles. This difference in drainage conditions between the two 

areas is puzzling and not easily explained.

After 1,000 feet or more of the Oligocene beds had 'accumulated in 

southwestern Montana the streams for some reason became more 

active and cut valleys in them, removing considerable material. 

Later the excavated areas were refilled with sediments that .generally 

were coarser and in Townsend Valley consisted almost wholly of 

gravel and sand. With them were buried the remains of animals 

indicating a Miocene age and showing that considerable time had 

been covered by the preceding interval of erosion. As explained 

under " Structure " (p. 30), the Oligocene beds had been moderately 

tilted before the Miocene beds were laid down. After the Miocene 

deposits had accumulated to the depth of 500 feet or more in Townsend Valley the structural movements were resumed, and mountain 

building and erosion became the most active of the geologic processes. At first, no doubt, the structural forces were dominant. The 

Tertiary beds and the old surface on which they lay were together 

arched and faulted. Existing mountains grew higher, parts of the 

valleys became relatively depressed, and new ridges such, as the 

Spokane Hills and the divide soutjh of Warm Spring Creek were 

elevated. There is no evidence available to fix the date of this 

period very closely. Probably it occupied part or all of Pliocene 

time.

After the mountain-building movements died out there followed a 

period of rest or crustal stability during which erosion produced a 

plain over the area of Townsend Valley, the remnants of which
42 GEOLOGY AND GROUND WATEB, TOWNSESTD VALUEY, MO2STT.

now form bench No. 1. In most places this bench is 300 or 400 

feet higher than the present streams and exhibits about the same 

slopes. Evidently the drainage of this plain escaped, northward 

through a valley having the same position as the present gorge of 

Missouri Kiver, north of Canyon 'Ferry. At an earlier time the 

Belt Mountains, as suggested by Atwood,19 may have formed the 

Continental Divide; if so, Townsend Valley drained southwestward. 

Before it became dissected the plain composing bench No., 1 covered 

the entire area of Tertiary beds in Townsend Valley and, in addition, extended for short distances across the older rocks at the foot 

of the mountains. To some extent its remnants lean up against the 

mountains but do not pass over them nor merge with their .slopes. 

Nearly everywhere the break between plain and mountain slope is 

sharp and distinct. During the erosion that produced this plain 

more or less of the Tertiary material was cut away, but as no remnants of it are now to be found above the plain the thickness removed 

is not apparent. It may have been considerable. Part, at least, of 

the plain was cut by the mountain streams working from side 

to side and reducing the area to grade at a level determined by the 

height of the drainage outlet at that time. While engaged in this 

work the streams brought out from tlie mountains considerable 

material described herein as bench gravel and spread it over the 

newly eroded surface, and at one place a email glacier from Mount 

Baldy descended upon the plain. Afterward the drainage outlet of 

the valley became lowered or the climate changed to such an extent 

that the streams were enabled to cut away most of bench No. 1 and 

develop a new plain about 100 feet lower, the remnants of which 

are described as bench No. 2. In time bench No. 2 was largely 

destroyed by renewed downcutting, ^tiich continued until the 

streams finally reached a point somewhat below their present level. 

After valleys had been excavated at this low level several of the 

streams, at whose heads were small glaciers, regarded as belonging 

to the latest or Wisconsin stage, brought in thick deposits of gravel. 

^Finally, after the glaciers had disappeared, the streams reworked 

part of the gravel, producing the valley bottoms and the low terraces that compose bench No. 3.

The small gorge of Missouri Biver at Canyon Ferry, which forms 

an excellent dam site that has been utilized by the Montana Power 

Co. (fig. 5; PI. II, 5), is a result of the river having become intrenched or superimposed on the side of the Spokane Hills while 

bench No. 2 was in process of being dissected. Apparently just 

before the downcutting began the river, meandering across the plain,

18 Econ. Geology, vol. 11, p. 702, pi. 27, 1916.
' ' PHYSIOGRAPHY . 4$

had set in against the hills at this particular point. As it deepened 

its channel the stream uncovered a small sgur of resistant rock 

(granodiorite) that until then had remained buried beneath the 

softer Tertiary beds. As a result deepening of the channel at ;fchis 

point was delayed, and for a time no doubt a considerable fall 

 existed. Eventually the stream cut through this difficult stretch, and 

the excavation of the valley was resumed and completed. During 

the last stage of erosion bench No. 2, in the valley alongside the 

gorge, has been worn away in places so that now if the gorge did not 

exist the river could not take its present course but would be compelled to remain out in the valley.

On the north side of the valley between Winston and Indian Creek 

and in some other areas no perennial streams issue from the mp.untains. Here the surface is covered with gravel deposited by ephemeral streams, which masks more or less completely whatever other 

features may have been developed. Apparently this gravel has been 

accumulating during most of the time represented elsewhere by the 

different benches and the valley bottoms.

Benches that in general are similar to those in Townsend Valley 

and probably are to be correlated with them are prominent features 

in most of the neighboring valleys in the mountainous region of 

southwestern Montana. In the Great Plains northeast of this region 

is a series of benches, described by Alden,20 that resemble the benches 

'.of Townsend Valley sufficiently to make their correlation seem plausible, though a gap of 70 miles or more between the nearest known 

remnants of each remains to be bridged.

The presence of a moraine on bench No. 1 in Townsend Valley has 

been referred to. In Deer Lodge and Flint Creek valleys similar 

glacial deposits occur on the highest bench, and in the Great Plains 

near Glacier National Park the highest bench is extensively overlain 

by till. The plain represented by the highest bench must have been 

completed before these deposits, which are regarded as early Pleistocene, came to place. How much time was consumed in its making 

is not indicated by the information available, but it was not begun 

until after the Miocene beds had been tilted. From the evidence at 

hand it appears quite plain that the trenching of bench No. 1 and 

the development and trenching of bench No. 2 took place between 

early and late stages of the Pleistocene and that in Townsend Valley 

at least bench No. 3 and the present valley bottoms are of postWisconsin age.

20 Alden, W. C., and Stebinger, Eugene, Pre-Wisconsin glacial drift in the region of 

Glacier National Park, Mont.: Geol. Soc. America 'Bull., vol. 23, pp. 687-708, 1912; vol. 

24, pp. 52^-572, 1913, Alden, W. C., Physiographic development of tfce northern Great 

Plains ((in preparation).
44 GEOLOGY AND1 GROUND WATER, TOWOSTSEHD VALLEY, MONT. 

MINERAL DEPOSITS 

MARBLE

Several of the Paleozoic limestones that form conspicuous reefs on 

the mountain spur that projects into the west side of the valley^

opposite 

marble.

Townsend show the texture and other features of decorative 

Specimens from the claims of D. P. Mumbrue are fine?

grained, show several attractive shades and patterns, and when polished appear remarkably pleasing and handsome. A common variety has a background of dark gray faintly mottled with brown 

and decorated witji splotches and threads of white and pinkish bufL 

Other varieties exhibit shades of yellow, red, and pink. In many 

of the beds grays that range from almost black to almost white predominate.

The deposits are practically undeveloped, but the natural exposures show large faces of clean marble (PI. II, A), and large blocks 

without cracks or flaws apparently could be quarried at several 

places. From points at which quarries could be opened the distance 

to a point on the Northern- Pacific Railway 2 miles north of Townsend ranges from 4 to 8 miles. A down grade exists all the way from 

the deposits to the railway.

DIATOMACEOUS EARTH

Diatomaceous earth, a substance composed of the siliceous sheaths; 

or skeletons of diatoms, a variety of extremely minute water plantsr 

was observed at tAvo places in Townsend Valley. It occurs in layers 

interbedded with the Oligocene clay and tuff and apparently accumulated at the bottom of a pond. One of the places is about a mile 

north of Beaver Creek, in a bluff facing Missouri River in sec. 27y 

T. 9 N., R. 1 E. Here two beds, each about a foot thick, crop out. 

In one the earth is almost chalk-white, of noticeably light weight,, 

and unmixed with any foreign material. In the other it is pale 

brown as the result of a small amount of impurities. The remaining" 

deposit is exposed north of Greyson Creek near the east line of sec. 

13, T, 6 N., R. 2 E., about 5 miles southeast of Townsend. It consists, 

of a bed 10 feet thick, light gray and thinly laminated like shale. 

Specimens show the earth to be mixed with a little lime and other 

substances. Possibly purer material exists below the surface, and it 

is likely that more extended search, particularly in the Beaver Creek 

area, will disclose additional deposits.

The uses of diatomaceous earth include the refining of sugar, deadening sound in walls, heat insulation in ceilings, boilers, etc., and the, 

manufacture of light-weight partition tile.
MINEKAL DBPOSITS . ; 45 

OIL

Information on which to base a positive conclusion as to the 

presence or absence of oil in Townsend Valley is not available, but 

the following facts and considerations bear more or less directly 

on this subject.

The .Belt series and all the granites and similar crystalline rocks, 

because of their age, metamorphism, or origin, may be excluded as 

possible sources of oil. Many of the remaining formations of the 

older group, however, which range from Cambrian to Cretaceous, 

are of the same age as formations that in other areas yield oil, but 

in Townsend Valley these rocks have undergone more severe folding 

and metamorphism than is common in the oil-bearing regions. The 

youngest (Cretaceous) and therefore presumably the most likely 

of these formations to contain oil crop out in places around the 

southern rim of the valley. Here they are moderately tilted, dislocated by faults, and intruded by igneous rocks.

Oil has not yet been found in deposits that correspond to the 

Oligocene and later formations in Townsend Valley. It is conceivable, of course, that oil might enter them from rocks with which 

they are in contact, such as the older group, but in Townsend Valley 

the two groups are separated by an unconformity that represents a 

long period of time during which the older group was deformed and 

deeply eroded. Presumably most of its oil escaped during this 

period and before the Oligocene beds were laid down.

COAL

A 21-inch bed of coal and several thinner layers are exposed in an 

open cut in sec. 17, T. o N., R. 3 E., on the south side of Sixmile 

Creek about 3 miles east of Toston. The coal is black, shows a few 

grains of amber-colored resin, and upon drying by exposure to the 

air slacks to a powder. It resembles the coals found in Tertiary beds 

elsewhere in southwestern Montana and probably is to be classed 

as subbituminous. Details of the exposure are given on page 23.

Formerly, as described on page 4, gold derived from placer 

gravel was the chief product of Townsend Valley and the neighboring hills. Many years ago, however, placer mining in this region 

declined to relatively small importance. The last work of noteworthy extent was the dredging .of a strip of valley gravel along 

the lower course of Magpie Creek east of Canyon Ferry. At present 

little is done except reworking or gleaning here and there in the 

old diggings. The total yield of gold in Townsend Valley and
46 GEOLOGY AND GROUND WATER, TOWNSEl$ri> VALLEY, MONT.

vicinity is estimated by persons familiar with the history of mining 

in that region to be several millions of dollars. ;

Since the decline of placer mining considerable quantities of gold 

and other metals have been produced from quartz lodes in the mountains that adjoin Townsend Valley. Most of the lodes are near 

Eadersburg and Winston and in other parts of the Elkhorn Mountains, described by Stone.21

GROUND WATER

WATER IN PRE-TERTIARY BOCKS

Although the rocks of the older groups (Cretaceous to preCambrian) are comparatively dense they contain numerous cracks, 

fissures, openings along bedding planes, and solution channels that 

allow water to circulate through them more or less freely and in 

the aggregate form capacious reservoirs. In the mountains surrounding Townsend Valley springs that issue from these rocks are, 

during the dry season at least, the chief source of the streams, which 

in turn supply most of the ground water contained in the Tertiary 

and later formations of the valley.

SPRINGS

Within the valley and just outside its limits are several springs in 

the older rocks, the most noteworthy of which are Big Spring, 

known also as Mammoth Spring, on the right bank of Missouri 

River about 5 miles south of Toston ; Bedford Spring, on the bench 

north of Indian Creek, about 4 miles northwest of Townsend; and 

Mockel Spring, at the head of Warm Spring Creek, about 12 miles 

southwest of Toston.

Big Spring, which includes the water escaping at several places 

along a distance of 200 feet or more, issues from talus and gravel below a steep slope and collects in a beautiful transparent blue pool 

alongside the track of the Northern Pacific Railway. Its flow, which 

is said to remain fairly constant throughout the year, amounted in 

May, 1922, to 64.4 cubic feet a second, or considerable more than 3,000 

miner's inches.22 In July, 1921, the temperature of the water discharged at one of the larger openings was 59° F. By means of a 

concrete dam and a canal part of the water is diverted to irrigate 

lands near Toston; the remainder falls directly into Missouri River. 

The talus and gravel from which the water escapes evidently form 

a shallow deposit that overlies limestone belonging to the older

R. W., 43eologie relations «f ore deposits in tfce Elfcbosii Mountains, Mooit. : 

U. S. GeoL gurregr Bull, 470, pp. 75-r99, 19H. , ,

88 The discharges of Big Spring, Bedford Spring, ami Mockel Spring, as glVen herein, 

were measured May 18, 1922, by W. A. Lamb, of the TJ. S. Geological Survey.
WAT8B IK PBE-TEE.TIABY BOOKS - 4$T

group. Doiibtless the water is discharged from an extensive solution 

channel in this rock. The spring is at the-lower end @f a horseshoe 

bend in Missouri River, the upper end of which is at Lombard, a 

distance of 1^4 miles in a straight line or 5% miles following the 

course of the river. At Lombard is the mouth of Sixteenmile Creek, 

which drains the country back of the spring. Beds of limestone occur in the area between the spring and Lombard and extend into tfce 

area crossed by Sixteenmile Creek. At Lombard Missouri River is 

about 30 feet higher than the spring. These relations suggest that 

most of the water discharged by thjs spring may come through underground channels that tap the river or Sixteenmile Creek in the 

neighborhood of Lombard.

Bedford Spring includes several points of discharge distributed 

over an area of about an acre, but most of the flow comes from three 

openings spaced about 100 feet-apart. The flow, which is used for 

irrigation and is said to remain practically constant throughout the 

year, aggregated in May, 1922, 3.09 second-feet, equivalent to about 

150 miner's inches. During the last 30 or 40 years, however, the 

flow is said to have decreased gradually by an amount equal to about 

one-fifth the present discharge. In July, 1921, the temperature of 

the water coming out of the principal openings ranged from 73^° 

to 74° F. Although this spring issues from gravel that rests upon 

Tertiary beds, its temperature and constancy of flow indicate that 

its source is in the older rocks, far below the probable depth to 

which the younger formations extend.

Mockel Spring includes the water issuing at several places around 

a small area in which, by means of an artificial dam, it is collected 

in a pond. The flow, which is said to remain nearly constant 

throughout most of the year, amounted in May, 1922, to 9.7 cubic 

feet a second, or about 485 miner's inches. The water rises from 

the Madison limestone, a member of the older rock group, from 

which it gushes somewhat vigorously, as if it were confined under 

pressure. In July, 1921, the temperature at the principal points of 

exit was 62'° F., a fact that indicates a rather deep source. The 

water is used for irrigation.

The analyses given on page 57 shows that the waters of these three 

springs are similar to most of the spring waters from limestone and 

dolomite such as occur among the older rocks. The waters may be 

classified as hard or moderately hard, but they are of excellent 

potable quality and suitable for most ordinary uses.

WEM.8 

Few wells have been made in the older rocks., One. 100 feet deep, 

on the land of Hannah Harrison aorth of Crow :CJr§ek, penetrates the 

Spokane shale and yields a moderate amount <f water. The shale
48 GEOLOGY AND GBOTJND WATEB, TOWFSEND VALLEY, MONT.

*

dips 20° toward the valley, and the water it yields is probably contained in the bedding planes. No other wells in the older rocks were 

examined.

WATEB IN TERTIARY AND QUATERNARY ROCKS

Except the clay or other fine-grained beds of the Oligocene series, 

most of the younger group of rocks contain within the saturated 

zone large amounts of water that is readily yielded to wells of 

ordinary size. Some of the Miocene beds and the valley gravel are 

very open textured and capable of yielding almost a third of their 

volume of water. The Oligocene sandstone and conglomerate are 

partly clogged with clay, but in places they are comparatively open 

and yield water rather freely.

The bench gravel is open textured, but because of its relatively 

high position it is devoid of ground water in most places. West 

of Missouri Kiver, however, in the area between Beaver Creek and 

Indian Creek, gravel that probably ranges from Tertiary to Recent 

contains ground water that is the source of Antelope Springs and 

a few other small springs mentioned on page 53. The water-bearing layer rests upon Tertiary beds that, as indicated by the well of 

Clark Dewell, about 3 miles south of Antelope Springs, are dry. 

Similar perched bodies of ground water probably exist in the gravel 

that overlies the different benches next to the mountains between 

Deep Creek and Confederate Creek.

WELLS IN THE BENCH LANDS

More or less information concerning the ground water is given 

by the well records available, of which a number are listed in the 

accompanying tables.

The wells listed below are situated in the bench lands and derive 

water from sand and gravel in the Oligocene and Miocene beds. 

This "table includes about three-fourths of the wells on the bench 

lands. Nearly all are drilled wells 5 or 6 inches in diameter, cased 

with iron pipe, and equipped with pumps operated by gasoline engines or windmills or, at a few, by both. Most of them were drilled 

within the period 1911 to 1919, at a cost for drilling and casing 

that ranged from $2 to $2.50 a foot. The wells south of Deep Creek 

end in gravel beds, some of which contain water under a slight pres-' 

sure that causes it to rise a few feet. Most of the wells are on 

bench No. 1, from which the depth to water ranges from 150 feet to 

250 feet or more. The yield of all may be rated as satisfactory in 

amount that is, it equals or exceeds the capacity of the pumps installed, of which the most effective raise the water at the rate of 

about 6 gallons a minute. As shown by an analysis of the water
WATER IN TERTIARY AST> QUATERNARY ROCKS

from the well of John Doherty (No. 11, p. 57), the water, though 

moderately hard, is of good quality for domestic use and for irrigation.

The wells of the group southeast of Warm Spring Creek end in 

gravel beneath a layer of hardened clay or "cement rock," apparently a member of the Oligocene beds, and at several places the waterbearing layer rests upon the bedrock or surface of the older rock 

group. The ground water appears to be under little or no pressure. 

The wells are distributed over a surface that rises gradually from a 

low terrace bordering the valley bottom toward a range of hills and 

probably corresponds in part to benches Nos. 1 and 2. The depth to 

water ranges from less than 100 feet to more than 300 feet. With 

one exception all the wells listed yield as much water as their 

pumps, ranging in capacity from about 2 to 7 gallons a minute, can 

handle. The well of W. H. Hunt has only a small yield, apparently 

owing to the fact that it enters quartzite that forms a high point of 

the bedrock. An analysis of the water from the well of John A. 

Peugh (No. 10, p. §7) indicates .that, though moderately hard, the 

water from these wells is suitable for all ordinary uses.

The wells between Duck Creek and Canyon Ferry penetrate waterbearing layers of sand and gravel, some of which belong to the Oligocene and others to the Miocene. The wells of Jeff Doggett, Todd 

& Lessing, J. A. Graveley, and W. H. Brown are on bench No. 2. 

Those of P. G. Gross and J. C. Thomas are on lower surfaces. All 

yield ample amounts of water for the needs of household and stock, 

except that at the time of examination the well of Mr. Graveley had 

become choked with sand. The analysis of water from the well of 

Todd & Lessing (No. 12, p. 57) is much like the other analyses and 

shows that the water is of good quality.

Records of wells in the bench lands

South of Deep Creek

«*

Owner

Mrs. W. J. Boone _

G. W. Gilham... .... 

John Doherty ___

Harry McCray^- .... 

J. C. Smith _____

Geo. Kamspeck ......

P. J. Meloy ____ .

Location

Sec.

14

12 

6

6 

9 

4 

4 

8 

18 

17 

16

T.

6N.

6N,

6N.

 6N. 

6N. 

6N. 

6N. 

6N. 

6N. 

6N. 

6N.

K.

2E.

2E. 

3£.

SE. 

3E. 

3E. 

3E. 

3E. 

3E. 

3E. 

3EDepth 

of 

well

Feet 

142

130 

235

210 

210 

210 

300 

190 

105 

153 

253

Depth 

to 

water

Feet 

112

100 

200

160 

160 

190 

280 

170 

66 

125 

190

Yield6.3

L

6+

L

7db 

6 

L 

L 

L 

L 

L

Bemarks

On bench No. 2. Penetrates Miocene 

gravel. 

In gulch below bench No. 1. 

0*t bench No. 1. Temperature 51° F. 

(Analysis 11, p. 570 

Bench No. 1. 

Do. 

Do. 

Do. 

Do. 

In gulch below bench No. 1 

Below bench No. 1. 

On bench No. 1.

« L, M, and S indicate, respectively, yields estimated between 6 and 4, 4 and 2, and less than 2 gallons 

a minute. -Figures give rates in gallons a minute at which the wells hare been pumped.
50 GEOLOGY AND GROUND WATER, TOWNSEND VALLEYj MONT.

Records of wells in the bench land» Continued 

Southeast of Warm Spring Greek

Owner

D. W. Jenklns.. ..... 

G. F. Watkins.......

Fred Sohrader.: __

Fred Sharman .......

W. H. Hunt... __ .

J. A. Peugh... .......

G.A.Tfflson........

H. H. Peugh.........

Location

Sec.

8 

35 

20 

4 

10 

30 

10 

16 

10

T.

4N. 

5N. 

4N. 

4N. 

4N. 

4N. 

4N. 

4N. 

4N.

..!..'

R.

2E. 

2E. 

2E. 

2E. 

2E. 

2E. 

2E. 

2E. 

2E.

Depth 

of 

well

Feet 

104 

168, 

163 

168 

178 

213 

23S 

300 

303

Depth 

to 

water

 Feet 

64 

140 

140 

148 

158 

160 

215 

220 

280

Yield"

L 

L 

L 

L 

L 

B 

7 

L 

L

Remarks

Temperature 51° F. (Analysis 10, p.

57-)

Between. Duck Creek and Canyon Ferry

Jefl Doggett .........

P.O. Gross ____ .

J, C. Thomas __ ...

Todd & Leasing. .....

W..H. Brown... __

33

18

31

6

3528-

9N.

9N.

9N.

9N.

ION.

ION.

2E.

2E.

2E.

2E.

IE.

IE.

60±

do

75 91 n

144

100

50

20

57

200

130

95

M

L

M' L

6

L

Temperature 50>i0 F,

sand.

0 L, M, and S indicate, respectively, yields estimated between 6 and 4, 4 and 2, and less than 2 gallons 

a minute. Figures give rates in gallons a minute at which the wells have been pumped.

Elsewhere there are but few wells that penetrate the Tertiary 

beds. One of the wells of Mrs. Elizabeth Hartop at Canyon Ferry, 

in sec. 11, T. 10 N., E. 1 W., is just above the valley bottom, and ends 

at a depth of 57 feet in hard Oligocene clay. This well receives an 

abundant supply of water from an open fissure in the clay. A 

well near by belonging to the school district is dug at the edge of 

the valley bottom and ends at a depth of 32 feet in water-bearing 

sand and gravel that lie below a bed of clay. The summer temperature of the water is 4Xy2° F. The well of Frank De Witt, in sec. 

34, T. 9 N., E. 1 E., at the foot of the bench lands east of Winston, 

is 100 feet deep and is in the tuff and volcanic conglomerate of the 

Beaver Creek section described on page 27. It yields a moderate 

amount of water which is noteworthy as being strongly mineralized 

and objectionable to the taste. The well of Charles Jacobs, in sec. 

22, T. 6 N., E. 3 E., half a mile south of Greyson Creek, is in a 

gulch below bench No. 2 and ends at a depth of 120 feet in waterbearing gravel of the Oligocene beds. The water stands at about 

the same height as the creek. The well is drilled, cased with 6-inch 

iron pipe, and equipped with a windmill and gasoline engine and is 

estimated to yield 5 or 6 gallons a minute. The temperature of the 

water is 50° F.

A bored well belonging to C. E. Stevenson, in sec. 8, T. 5 N., E. 1 

E., at Eadersburg, is 3 inches in diameter, passes through yellow 

and brown clay of the Tertiary beds, and ends at 50 feet in a water-
WATER IN TERTIARY AND QUATERNARY ROCKS 51

bearing layer of sand. It yields an ample supply of water which is 

shown by analysis No. £ (p. 57) to be of good quality for general use. 

The temperature of the water as determined in July is 50° F.

The drilled well of Philip Mockel, in sec. 10, T. 4 N., B. 1 E., on 

a low tench south of Crow Greek, is cased with 5-inch iroto pipe and 

ends at a depth of l%&/2 feet in gravel belonging to the Tertiary 

beds. It is equipped with a gasoline engine and it is said to yield 

continuously as much water as the pump can raise, estimated at 4 

or § gallons a minute.

WELLS IN".THE VALLEY BOTTOMS ,.;

The valley bottoms and bench No. 3 contain a large number of 

shallow wells that receive practically inexhaustible supplies of water 

from the valley gravel. Most of them are dug w&Qs 3 or 4 feet in 

diameter; the remainder are drilled or driven wells of small size. 

The kinds of casings include wood, stone, brick, tile, and iron pipe. 

Many of the wells are equipped with windmills or gasoline engines; 

in others the water is raised by hand power applied to pumps of 

different types, and at a,few wells the old-fashioned sweep, windlass, or pulley was still in use. The summer temperature of the 

water determined in several wells is 47^° F., or a little more than 

4° above the average annual temperature of the region. Twelve 

representative wells are listed in the following table. Analyses of 

samples from three of these wells (Nos. 6, 7, and 8, p. 57) show that 

the water is somewhat hard but is suitable for all ordinary uses.

Records of wells in the valley bottoms and on bench No. S

Owner

Parks Trail ranch.. 

John Hossfeldt ...... 

John Rothfus .......

B.G.Norton--- 

Viola Hahn... ......

G. N. Mires 

W.C.DanielW.J. Gaab... ... ...

Mrs. W. F. Fisher.. 

C. J. Sheriff..... _ .

Location

Sec.

14 

8 

' 28 

33 

23 

6

6

29 

8 

26 

15 

10

T.

4N. 

4N. 

5N. 

7N. 

8N. 

8N.

8N. 

8N. 

8N. 

9N. 

9N. 

ION.

R.

IE. 

2E. 

2E. 

2E. 

IE. 

IE.

2E. 

2E. 

2E. 

IE. 

IE. 

1 W.

Depth 

of 

well

Feet 

60 

36 

40 

16 

25 

50

30

35 

87 

12 

20 

16

Depth 

to

water 

Feet 

45 

33H 

30 

12 

20 

20

20 

10

75 ± 

10± 

14 

14±

Remarks

Temperature 47J#> F. (Analysis 6, p. 67.) 

Near slough. 

Temperature 47Ji° F, Water leyel raised by,- Irrigation. (Analysis 8, p. 57.)

Temperature 47V£° F. (Analysis 7, p. 57.) Water level raised by irrigation. 

Water level rises and falls with the river.

. >,,- 1

PUBLIC WATER SUPPLIES

Townsend obtains its public water supply from the valley gravel 

beneath the bed of Deep Creek by means of drains or infiltration 

galleries near the east line of sec. 36, T. 7 N., E. 2 E., about 5
52 GEOLOGY.AND GROUND WATER, TOWNSEND VALLEY, MONT.

miles east of the town. The galleries, which are lined with 24-ineh. 

split drain tile, aggregate 200 fleet in length and lie a few feet 

below the stream level. They discharge into concrete-lined chambers 

or wells from which the water flows by gravity through a tile 

pipe into two open concrete reservoirs that have a combined capacity 

of 360,000 gallons. The reservoirs are -about 220 feet above the town, 

to which the water is delivered under the pressure of gravity. This 

waterworks was constructed ia 1912 at a total cost, including 3 

miles of mains and several fire hydrants, of about $60,000, The 

daily consumption of water in 1921 ranged from less than 200,000 

to nearly 300,000 gallons, practically all of which was used by the 

inhabitants for ordinary household purposes, including the watering 

of lawns and gardens. The amount of water yielded by the infiltration galleries was estimated to range from 240,000 gallons a day 

in the winter to 380,000 gallons a day in the summer, the summer 

increase probably being .due to irrigation. Apparently the yield 

could be largely increased by extending the. galleries and constructing a dam or using other means to cut off the flow that doubtless 

escapes through a lower layer of the gravel. The quality of the 

water is satisfactory, although the analysis "(No. 4, p. 57) show^ more 

dissolved solids and hardness than are found in most of the other 

waters analyzed. On account of the high sulphate the water will 

form hard scale in steam boilers if used without treatment.

The Toston public water supply is furnished by the underflow of 

Sixmile Creek, an intermittent stream. The water is diverted by 

a bedrock dam and drain at a point about 2 miles east of the town 

and flows by gravity to a covered concrete reservoir having a capacity 

of about 50,000 gallons. It is distributed to the town, which is about 

150 feet lower than the reservoir, by the pressure due to gravity. 

The total cost of the waterworks, including mains and fire hydrants, 

was about $17,500. The amount of water available at the source 

varies from time to time but is estimated to average about 50,000 

gallons a day during the summer. The chemical character of the 

water is shown by analysis (No. 5, p. 57) to be very similar to that of 

the Townsend supply.

SPRINGS

At many places in the valley bottoms the ground water rises, 

forming seepage areas and springs that in the aggregate discharge 

a considerable volume. Several springs of this kind in the bottom 

adjoining Missouri Eiver west of Canton post office are estimated to 

discharge in all from 10 to 15 cubic feet of water a second; the 

flow is larger during or after the irrigating season than at oth$r 

times. Springs in sec. 27, T. 8 N., E. 2 E., 2^ miles east of Canton, 

rise from the valley gravel and form a small creek. Water rising
IN - TEETIABY AND QtrATEBSSAEY EOGKS 53

into the valley bottom adjoining the lower course of Crow Creek 

forms swampy areas in several places, two of which are the sources 

of considerable streams. A spring on the land of Adnah Kimpton in 

sec. 24, T. 5 N., E. 1 E., about 5 miles west of Toston, was estimated 

in July, 1921, to be discharging about 100 gallons a minute, or about 

0.2 cubic foot a second. The water issues from sand and gravel 

and forms a shallow pool in which bubbles of an inert gas, ap,- 

parently carbon dioxide (CO2 ), are continually rising. The temperature of the water was 64° F., and its source is probably rather 

-deep in the gravel or the Tertiary beds. On the south side of the 

valley bottoms adjoining Greyson Creek in sec. 17, T. 6 N., E. 3 E., 

is a developed or dug out spring that, at the time of examination, 

was estimated to be discharging about 60 gallons a minute. The 

temperature of the water was 47^° F., the same as that of the 

ground water generally at shallow depths.

Antelope Springs, on the A. B. Cook ranch, in sec. 27, T. 8 N., E. 

1 E., west of the river, and two small springs 1^ and 3^ miles 

northwest of them rise in boggy areas. They discharge comparatively little water, and apparently their supply comes from the 

gravel that overlies the Tertiary beds in this area. The distribution of these springs along a northwest line suggests that they mark 

the position of a fault or fold that elevates a water-tight bed and 

thus cuts off the ground flow toward the river. Near the mouth of 

Avalanche Creek, in sec. 29, T. 10 N., E. 1 E., a small spring that 

rises at the edge of the bench lands yields water that tastes slightly 

bitter and upon evaporation deposits thin crusts of white " alkali." 

The temperature of the water was 49° F., and its apparent source is 

the valley gravel.

WATER 'TABLE

In Townsend Valley the water table or upper surface of the saturated zone is nearly level but generally slopes gently in the same 

direction as the land surface. The water table is continuous with 

the surface of Missouri Eiver and, except possibly at flood stages, 

rises gradually from that stream toward the mountains. It is continuous also with the surfaces of most of the perennial streams that 

join the river, but instead of rising under the lands that border them 

It generally either slopes gradually downward away from the streams 

or maintains the same level. For a short stretch near Winston 

Beaver Creek lies wholly above the water table, being separated 

from it by an aerated zone of considerable depth. Possibly some of 

the other perennial streams and probably all the intermittent and 

ephemeral streams are similarly perched. In most places in the 

valley bottoms bordering Missouri Eiver,, Deep Creek, Crow Creek, 

and several other streams the position of the water table ranges
54 GEOLOGY AND GROUND WATER, TOWFSEND VALLEY, MONT.

from the surface to a depth of 20 feet. At 

Winston, in the flat adjoining Beaver Creek,, 

however, the depth to ground water is, or was 

before irrigation became general, as much as50 feet below the surface. As it passes from, 

the valley bottoms under bench No. 3 thewater table does not change in form or slope, 

and its depth therefore ranges from 30 feet 

to 70 feet or more.

In some places in the bench lands between 

Deep Creek and Greyson Creek a water table 

is not present, owing to the occurrence of 

water-tight layers that confine the ground 

water. In these places the water rises in thewells to about the level of the water table in 

adjacent tracts. In the area between these 

streams the water in wells stands from 160* 

to 250 feet or more below bench No. 1 (fig, 6) 

and the head decreases toward the river with, 

about the same gradient as Greyson Creek 

and also decreases away from Greyson Creek 

and toward Deep Creek, which flows at a 

lower level. Southeast of Warm Spring 

Creek the water table extends horizontally 

or with a slight descent under a rising surface (fig. 7). Between Duck Creek and 

Canyon Ferry the water table so far as known: 

lies somewhat below the local streams, particularly in the area north of Confederate 

Creek, which is watered by several intermittent streams. As shown by existing wells it 

ranges from 100 to 200 feet below the surfaceof bench No. 2, and within a small area at 

least it stands 150 feet higher than Missouri 

River at a distance of 3 miles from that 

stream. In the remaining areas of bench 

lands little definite information concerning; 

the water table is available. Between Greyson and Sixmile creeks its level as indicated 

by the well of Charles Jacobs, described on; 

page 50 is near that of the local streams*. 

West of Missouri River, in the area between Beaver Creek and Indian Creek, Antelope Springs and other small springs mentioned on page 53- 

rise from gravel that overlies the Tertiary beds. The distribution

fe
WATEB IF TEBT1ABY AHD QTJATEBNABY BOCKS:;

than 

on

of these springs along a 

position of a fault or fold 

tween the springs and the 

but its upward slope is less 

ground water, as mentioned 

tiary beds. Whether anothe 

in the Tertiary is not known.

In the area south of Bade 

the water table as indicated 

low as Crow Creek or lower.

In the valley bottoms the 

throughout the year. It rises 

seasons and falls at other 

5 to 15 feet or more. In many 

table has occurred since i

northwest line suggests that they mark the 

elevates a water-tight layer. Bemo intains the water table doubtless rises, 

that of the surface. This body oi 

page 48, is perched above dry Terwater body exists at a lower level

times

rrigE.tion

NW.

 sburg and southwest of Crow Creek 

by a few widely scattered wells is as

height of the water table is not constant 

during the high-water and irrigating 

i, the total fluctuation ranging from 

places a permanent rise of the water 

was introduced. As a result cer^ 1

SE.

m^tsm^^^^z^sz-z

fEET

 4,500

 4,000

 $500

FIG0BJB) 7. Diagram snowing water table Southeast of Warm Spring Creefe

tain areas that are said to have been formerly well drained are now 

too wet for cultivation. A permanent rise in the water table of 30 

ieet is shown by the well of G. N. Mires at Winston. .In the bench 

lands the water table appears to be not yet affected by irrigation, 

and, so far as known, its level does not change much with the seasons.

SOURCE OF GROUND WATER - ,

In humid regions most of the ground water is derived directly 

from rain or snow, a part of which sinks until it reaches what is 

called the zone of saturation. In these regions the water table conforms in a general way with the surface of the land. It is elevated 

and depressed, respectively, where there are hills and valleys, but its 

differences in elevation are somewhat less than those of the land 

surface. In Townsend Valley, owing to the comparatively dry climate, the amount of rain water that enters the ground is generally 

too small to sink very far, and, except where the water table is near 

the surface, it does not reach or add to the ground-water body at all 

but is soon absorbed by plants or drawn back by capillary attraction 

and evaporated. In this area the chief sources of the ground water 

are streams that flow from the mountains or other areas of greater 

rainfall, and in addition water probably enters the Tertiary beds?
56 GEOLOGY AND GROCER WATER, TOWNSEND VALLEY, MONT.

from springs in the older, rocks beneath them. As a result the water 

table is independent of the land surface, its slope and position being 

controlled chiefly by the streams. Between the mountains and Mis-- 

souri River many of the streams lose considerable water to the 

gravels composing the valley bottoms. Several small streams, including Sixmile, Ray, and Gurnett creeks, sink entirely before they 

reach the river. Presumably all the larger streams contribute in 

the same way a part of their flow to the ground water, and since the 

settlement of the valley irrigation has added much water to the 

saturated zone.

In the bench lands between Deep Creek and Greyson Creek the 

head of the water in wells indicates that the ground water moves 

from Greyson Creek diagonally downward through the bench to^ 

ward both Missouri River and Deep Creek. Therefore Greyson 

'Creek appears to be the chief source of the ground water in this areaSoutheast of Warm Spring Creek the height and relation of the 

water table (fig. 7) indicate that that stream is one of the sources 

of the ground water, another being small springs that rise in the 

neighboring hills and sink at the edge of the valley. Between Duck 

Creek and Canyon Ferry the ground water evidently is derived 

from a number of mountain streams, most of which are either intermittent or ephemeral. On the west side of the valley between Beaver 

Creek and Indian Creek a number of small springs and ephemeral 

streams from the mountains supply ground water to the gravels, 

overlying the bench lands. The summer flow of Indian Creek, said 

to be as much as 75 miner's inches, or 1% cubic feet a second, sinks 

before the stream leaves the mountains and doubtless forms a body of 

ground water, as yet undiscovered, in the bench lands below.

Springs are fairly plentiful in the older rocks where they are not 

covered or concealed by rocks of the younger group. Within the 

covered area, which comprises most of Townsend Valley, at least 

one spring, Bedford Spring, breaks out of the older rocks and makes 

its way to the surface through the overlying beds. It is probable 

that other springs issue within the covered area and add their flow 

to the ground water, though there is no basis for estimating the 

amount thus contributed.

QUALITY

The analyses given below show about the average composition of 

the ground water in most of Townsend Valley, The samples were 

collected in midsummer. Earlier in the season many of the shallow 

wells in the valley bottoms are said to yield softer water, chiefly as 

a result of irrigation with the water from snow-fed mountain 

streams. The wells in the bench lands probably show little or no 

change with the seasons.
-IIT 9CEETIARY AXO> QUATERNARY BOCKS ,

Analyses of waters from, springs and from public auppHes <fc» &otcns4»& 

[Analyzed by C. S. Howard. Parts per million]

Silica (SKh) .... » ...... .. ,... .. . . .

Iron(Fe) . _ . __ ...

Calcium (Ca). ., . ........ .. .» 

Magnesium (Mg) __________________

Sodium and potassium (Na+K) (calculated) _ - __

Sulphate radicle (SOt) ________________

Chlorfderadicle (Cl) .._................. .... ___.

Nitrate radicle (NOs). ......... ................ ...

Total dissolved solids at 180° C.. . .... _____ ..

' 1'

- 30

46

17

17

0

183

579 n

.49

259

185

Jan. 25,

1922.

2

16

0.08

60

19

18

0

151

127

ao

^tafi

228

Aug. 27,

1921.

3

32

a 10

70

34

32

0

332

92

11

408

314

Aug. 18 .

1921.

4

Stt

0.06

109

37

60

0

331

241

23

Trace.

706

424

1921.

5

46

0.10

108

37

45

0

329

192

35

Trace.

6S7

422

1921.

1. Big Spring, SE. M sec. 6, T. 4 N., R. 3 E., 5 miles southeast of Toston, on right bank of Missouri 

River near Northern Pacific Railway.

2. Bedford Spring, NE. M sec. 23, T. 7 N., R. 1 E., about 4 males northwest of Townsend.

3. Mockel Spring, NE. J£ sec. 27, T. 4 N., R 1 E., about 12 miles southwest of Toston.

4. Townsend public water supply. Infiltration gallery below bed of Deep Creek, near east line of sec. 

36, T. 7 N., R. 2 E., about 5 miles east of Townsand,

5. Toston public water supply. Drain below bed of Sixmile Creek in sec. 13, T. 5 N., R. 2 E., about 

2 miles northeast of Toston.

Analyses of water from wells in Townsend Valley 

[Analyzed by C. S. Howard. Parts per million]

Silica (SiOs).. . ........ .

Calcium (Ca) ..................

Sodium and potassium (Na+ K) 

(calculated) ____ , __ ..

Bicarbonate radicle (HCO») ..jf.

Chloride radicle (Ol) ...........

Nitrate radicle (N03) . __ -

Total dissolved solids atltSO" C. 

Total hardness as CaCOg (calculated) . __ .... ... ____ .

6

14 

Trace. 

48

22

21 

0

188 

87

ao

.50 

306

210 

Aug. 25

7

26 

0.11 

80 

24

26 

0 

325 

63 

15 

2.8 

407

2% 

Aug. 26

8

17 

0.14 

61 

 14

21 

0 

132 

46 

67 

5.6 

340

210 

Aug. 23

9

26 

0.09

 57 

19

52 

0 

170 

148 

21 

13 

437

220 

Aug. 24

10

29 

0.10

41 

15

40 

0, 

179 

73 

27 

.46 

336

164 

Aug. 22

11

19 

 0.08. 

36 

19

13 

6.0 

189 ' 

25 

3.0 

.96 

221

188 

July 22

12

14 

0.09 

41 

36

16 

0 

265 

60 

40 

.58 

306

250 

Aug. 19

6. Driven well 16 feet deep of B. Q. Norton, in SW. M see. 38, T. 7 N., B. 2 E., about 2 mil«s east of 

Townsend.

7. Driven well 35 feet deep of W. J. Gaab, in SE. M sec. 29, T. 8 N., B. 2 E., at Canton.

8. Dug well 50 feet deep of G. N. Mires, in SW. M sec. 6, 8 N., R. 1 E., at wlnston.

9. Bored well 50 feet deep of C. R. Stevedson, in SW. Y& sec. 8, T. 5 N., B. 1 E., at Radersburg.

10. Drilled well 235 feet deep of John A. Peugh, in SW. M sec. 10, T. 4 N., R. 2 E.

1L Drilled well 235 feet deep of John Doherty, in SE. M sea 6, T. 6 N., R. 3 E., about 6 miles east of 

Tcwnsend.

12. Drilled well 144 feet deep of Todd & Lessing, in SE. M sec. 35, T. 10 N., R. 1 E, about 10miles 

southeast of Canyon Ferry.

The analyses show that there are no unusual features in the composition of the waters examined. These waters contain the substances that are dissolved from rocks and soil by all natural waters. 

The main constituents are calcium, magnesium, bicarbonate, and 

sulphate. The calcium and magnesium cause the iiardness that i& 

the principal characteristic of the waters,

In Townsend Valley waters that have between 150 and 200 part?' 

per million of hardness are generally regarded as slightly hard, and
38 GEOLOGY AXJJr GROUNDi WA37EB, TOWNSEND VAIJUBY> MONT.

those with 200 to ,300 parts as moderately hard. In some, parts1 ot 

the United States, where the hardness o| the water regularly used 

for public and priyate suplies is less than 50 parts per million, water 

with 200 parts per million of hardness would be considered ver^ 

hard. It is generally profitable for <x>mmercial laundries to install 

.apparatus for softening water that has more than 100 parts per 

million of hardness. Softening of hard water is necessary for the 

efficient operation of steam-boiler plants. So far as .the samples

 cover the area the softest water is found in the bench landls and the 

hardest in the gravels beneath Deep Creek and Sixmile Creek.

Except for hardness the waters for which analyses are given in 

the tables should be entirely satisfactory for all ordinary uses, both

 domestic and industrial. They are also suitable for use in irrigation.

ARTESIAN WATER 

GENERAL CONDITIONS

Artesian water is ground water under sufficient pressure to rise 

above the water-bearing layer if, for example, this layer is penetrated by a well. Like ordinary ground water, artesian water usually 

occurs in the pores and cavernous spaces in an open-textured rock. 

The pressure, which is the distinguishing feature, is caused by the 

water being confined between impermeable beds or otherwise prevented from escaping from the layer that contains it. Commonly 

artesian conditions exist where a bed of sandstone or other permeable rock crops out on relatively high land and extends beneath 

.an adjacent lowland. If the permeable bed is exposed at its outcrop 

to abundant rain or to the seepage from streams and if it is elsewhere properly incased or covered by layers of shale or other watertight material, it may become filled with water under artesian pressure. It is evident that little or no artesian pressure can arise in any 

part of a bed that lies above the lowest point of the outcrops or 

above the lowest point at which there is free leakage. It follows as 

.a matter of course that flowing wells will be restricted to areas that 

are lower than such outcrops or leakages.

It appears that the Miocene beds, the bench gravel, and the valley 

gravel, because of their open texture and lack of confining layers, 

are generally incapable of holding artesian water. On the other 

hand, the Oligocene beds consist largely of clay in which are incased 

a few layers of sandstone and conglomerate of sufficiently open texture to hold considerable water and allow it to pass through them 

freely. These layers dip gently below the surface, and their outcrops are crossed by streams from which they doubtless receive
ARTESIAN WATER , , , . , 59

abundant seepage. Therefore at least part ol the ccwjjtiote 

«ary to produce artesian pressure are present, and in places, 

by wells in the bench lands south of Deep Creek* the? water .rises a 

little above the water-bearing beds., Nearly everywhere that they 

are to be seen, however, these beds crop out at levels lower thfcn the 

lands they dip under. Along the zone of anticlines described op 

page 31 the water-bearing beds either crop out at the surface or beneath permeable gravel that underlies the lowest parts of the valley, 

and it is thus evident that in general they can not hold water under 

.sufficient pressure to produce flowing wells. Possible exceptions to 

this condition may exist in small areas, such as the bench lands 

^between Indian Creek and Winston, where the structure and other 

features of the Oligocene are obscure.

The fact that Mockel Spring gushes out somewhat vigorously suggests that bodies of water under artesian pressure probably exist here 

and there in the fissures or caverns of .the older rocks. Except as their 

presence is indicated by springs, however, the discovery of such 

bodies, especially where the rocks are concealed by the Ternary deposits, would be difficult if not impossible.

LOCAL CONDITIONS

Between Deep Creek and SisemUe Creek. The Tertiary beds are 

"bent into an arch, or anticline, along an axis that lies about 5 miles

 east of Townsend and that extends from Deep Creek to Sixmile 

Creek. East of this arch the beds dip toward the mountains, so 

that the outcrops of possible water-bearing beds are lower than the 

surface of the bench lands under which they dip, and therefore they

-evidently could not supply these lands with artesian water. West of 

the arch the beds dip westward, and where their outcrops are crossed 

t>y Deep Creek and other streams they doubtless receive abundant 

seepage. An artesian area therefore possibly lies west of the arch, 

but it is limited to the lowlands in the middle part of the valley, 

which are already irrigated. Townsend is in this possible artesian 

area.

North of Deep Creek. From Deep Creek northward to the end

 of Townsend Valley, at Canyon Ferry, the possible water-carrying 

formations dip eastward, or toward the mountains, so that most of 

the points at which the outcropping beds could receive much water 

are lower than the lands for which flowing wells are desired. West 

of Missouri River along Beaver Creek below Winston the beds dip

-eastward, pass under the gravel flat along Missouri River, and extend beneath the bench lands beyond. Farther east they become 

thinner and finer textured and gradually give place to layers of
$0 GEOLOGY AND GROUND WATER, TOWNSEND VALLEY, MONT.

sand and gravel that were brought down from the mountains. The 

lowermost beds, which cr$p out along Beaver Creek about 4 miles 

above its mouth, may carry water under artesian pressure eastward 

beneath Missouri River said under the bench lands beyond, though 

tbe tendency of the beds to thin omt And the possible ooeiirrencfe of 

faults or other causes of leaks make the limits of the possible artesian area decidedly problematic. In the benches immediately east 

and west of Missouri River die depth to the supposed water-bearing 

beds is estimated at 2,000 feet or more.

West of Missouri River. Between Bedford Spring and Winston 

a rather thick sheet of gravel, which was evidently spread out by 

streams that issued from the mountains on the west, covers and 

conceals the Tertiary beds so effectually that their structure is not 

apparent. A clue to it is perhaps afforded by Antelope Springs and 

two'other small springs, which break out along a line that trends 

northwestward and that probably marks the outcrop of an impervious bed which prevents farther movement of the ground water 

eastward. The ground water probably has its source in several 

small intermittent or ephemeral streams that head in the mountains 

at the west, and artesian wells may possibly be obtained in a part 

of the gravel slope between the springs and the mountains, though 

this is very uncertain.

The area south of Crow Creek comprises a wide flat along the 

stream and rather extensive low bench lands south of it. Tertiary 

lake beds appear to underlie most of this area, but as the older rocks 

project through them in places, their thickness is evidently not great. 

The structure of the Tertiary beds is concealed everywhere except 

on the western edge of the area, near Radersburg, where they dip 

gently eastward beneath gravel that covers the flat along Crow 

Creek. Within this flat, therefore, they may possibly contain artesian water.
INDEX

Pag

Antelope Springs, description of. _. 53 

Artesian water, conditions governing.._ 58-60

Bedford Spring, description of________ 47,57 

Bench gravel, nature and deposition of.__ 35-36 

Bench No. 1, origin of .__... . 41-42

plate showing_________ __.. 8 

Bench No. 2, origin of____________ 42

plates showing ...._.. . 8,9 

Bench No. 3, origin of- ._... 42 

Benches, description of ____ __ 6-8

wells in . . . .. . 48-51 

Big Spring, description of.. . 46-47,57

Climate of the valley _____________ 10-13 

Coal, exposure of..________...._... 23,45

Diatomaceous earth, deposits of _______ 44 

Drainage of the valley____________ 9-10

Exploration and settlement ... . 3-5

Faults that cut the beds.. . 16-17,32-33 

Field work, record of._______ __- 1-2 

Folds in the beds_______________ 31-32

Geographic features of Townsend Valley._ 1

Glacial debris, deposition of ___ _ 37-38

Gold, development of mining.. _ ., 4-5

occurrence in the bench gravel ____ 35-36

production of_______________ 45-46

Hills of the area_______ *_______ 9 

Industries of the valley ___________ 4-5

Lake Sewell, plate showing_________ 9 

Literature on the Tertiary rocks of the valley. 17-21

Marble, deposits of ______________ 44 

plate showing . 9 

Mineral deposits of the valley _... 44-46 

Miocene rocks, nature of ._________ 29-30 

Mockel Spring, description of________ 47,57

Page

Oil, possibility of its presence.___. ___. 45

Oligocene rocks, deposition of __..___ 40-41

nature of.. _ 22-29

Physiography of the valley ___ ___. 38-43

Pre-Tertiary rocks, stratigraphy of ___ 13-15

structure of . 15-17

water in_____.___ . 46-48

Quality of the ground water ____ ___ 56-58

Quaternary deposits, nature of... __.. 34-38

water in . _ .......__ 48-58

wells in..____._____ .. 51

Rainfall in the valley 11-13

Source of the ground water___ ... 55-56

Spokane Hills, plate showing________ 9

Springs, analyses of water from 57

in pre-Tertiary rocks..___ __.. 46-47

in valley gravel. ___ 52-53

Summary of the report 2-3

Surface, old, origin of . 38-39

Tertiary rocks, age and correlation of..... 33-34

literature of 17-21

stratigraphy of...-_ ..._ . 22-30 

structure of _ 30-33

water in_____________ ___. 48-58 

Topography of the valley________ 5-9,38-43 

Toston, public water supply of 52,57 

Townsend, public water supply of 51-52,57

Valley bottoms, description of 8-9 

wells in_____________ - __ 51

Valley gravel, nature and distribution of. 36-37 

springs in. 52-53

Vegetation of the valley.. ___ .. 10

Water supplies, public.._.... 51-52

Water table, depth to ___ ....... 53-55

Wells, analyses of water from 57 

in pre-Tertiary rocks...._ 47-48

in Tertiary rocks ... . 48-51

61

O