Bulletin No. 217 Series B, Descriptive Geology, 32

DEPAETMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

CHARLES B. WALCOTT, DIRECTOR

NOTES

ON THE

GEOLOGY OF SOUTHWESTERN IDAHO AND 

SOUTHEASTERN OREGON

BY

ISRAEL O. HUSSELL

WASHINGTON

GOVERNMENT PRINTING OFFICE

1903
o

OS

LA
CONTENTS.

Page.

Introduction.-.---...___-...---.-----.__..-_--_____._-____.__._._.-__--._. 7

Climate and vegetation .-....-..._......_....__.._________._____.______... 8

Topography ...............................I............................. 12

Mountains -----...----...-.----.-.--.-................................ 13

Valleys................................................................ is

Hydrography............................................................. 21

Drainage slopes.....---..-..-.-.---.-..-...._........................ 21

Streams .--.--.-..-. ....-.....-...........-........... -..-......-... 21

Springs and artesian wells ................_-......................-.... 23

Artesian basins.......................... ............................ 25

Lakes............... ........................... ................_... 27

Cow Creek lakes.--..-.---------------..--..-.-...- ....... ...... 27

Malheur and Harney lakes -..-.-.-.-.---..-..-........--..-.-.... 29

Silver Lake ........................................................ 32

Lakes of Alvord Valley ........................................... 33

Fluctuations of lakes, efflorescences, etc.......................... 34

Geology--------------.----.-..-------..------.-..--....--.....---------- 36

Eecent volcanoes .----.-....-.--.-.----.-.-...-..--..-.-.-..--.-.-..- 36

Cinder b'uttes............^....................................... 38

Breached cinder cones and floated crags.of tuff................. 39

Volcanic bombs.-..--..........-.-..-....-..---.---..-.-.--.. 4.0

Lapilli cones, cinder cones, etc ..---.............-.- ......... 45

Jordan craters. ................................'...'.. ....... ...... 48

Crater No. 4.............. ................................... 49

Driblet cones-and " ovens"-.-.---. .......................... 52

Lava gutters .--.-...-..-..-..-.---......---..-....-.-..-..--.- 52

Lava" flow ...-.....-...-..----...-....-.-.-.-----.----.- -... 58

Diamond craters...-.--.-.-...--. ..--.--...........-..-.-..-.....- 54

Bowden crater..._........-......--....-.-.--...-..-.-.-...-.---- 57

Summary ....................................................... 58'

Tertiary formations.. ---....---.-.-..-.-..--.- .-.-.--.--.-.-..- ...... 59

Sedimentary rocks.........-.....-..--..._--......--.-.-..--....- 60

Igneous rocks ......-..-...-----.-..-.-...--.--.----.....---.---- 64

Volcanic rocks.---.------..----.-------.----------.-.--.---.. ' 64

Dike rocks ....--......--.----.-----..----..----..----.---.-. 66

Structure.-....-............--.------.-.------..-..-.-...-..----.--.- 67

Mineral resources.-............--..--..---..---...-..---.-..-...-.--.--.- 69

Petroleum........... ..........-..-....-...-.....-...--.-.---.-.---.- 69

Conditions favoring natural storage of petroleum, and rock gas .... 69

Index ....................................... ......................... 81

ILLUSTRATIONS.

Page. 

PLATE I. Sketch map of southwestern Idaho and southeastern Oregon...-. 8

II. A, South shore of Malheur Lake, Oregon, Salacornia growing in 

alkali; B, Eolian mounds on border of playa near Iron Mountain, Oregon.._-_-_-_-......__._.__._._..______________._.__._ 30

III. A and B, Crags of tuff on lava flow, Cinder Buttes, Idaho ....... 38

IV. A, Island of lapilli in lava stream, Cinder Buttes, Idaho; B,

Scoria and bomb cones,'' The Ice Wells,'' Cinder Buttes, Idaho. 40

V. Volcanic bombs, Cinder Buttes, Idaho...................---....- 40

VI. Volcanic bomb, Cinder Buttes, Idaho..-.....-.-..---........... 42

VII. Volcanic bombs, Cinder Buttes, Idaho.-...-.,.-.-.--........... 48

VIII. Volcanic bomb, Cinder Buttes, Idaho.................... ...... 48

I.. Sections of vesicular volcanic bombs'....................... .... 44

X. A, Cracked surface of volcanic bomb, Cinder Buttes, Idaho; B, 

Fragment from a cinder cone, showing dense portion due to 

hardening of splashes of liquid lava, Cinder Buttes, Idaho.... 44

XI. A, Driblet cone or "oven," Jordan Craters, Oregon; B, Driblet

cone, Diamond Craters, Oregon .............................. 52

XII. A, Fissured pahoehoe lava, Jordan Craters, Oregon; B, Ad lava

surface, Cinder Buttes, Idaho .-.....----...-.--.-.-..-.'-.--.- 58

XIII. A and B, Margins of lava flows, Cinder Buttes, Idaho. ---....-.. 58

XIV. A and B, Lava gutters, Jordan Craters, Oregon................. 60

XV. A, Pressure domes in recent lava, Jordan Craters, Oregon; B,

Pressure ridge in recent lava, Diamond Craters, Oregon .... 60

XVI. A and B, Weathering of riru rocks of basalt above soft terranes. 60 

XVII. A and B, Exposiires of volcanic dust of Tertiary age near Beulah,

Oreg--.--. .....................i...........................'... 62

XVIII. A and B, Exposures of Tertiary lake beds,.Owyhee River, Oregon. 62 

FIG. 1. An ideal geological section illustrating the manner in which petroleum and natural gas accumulate in anticlines, and also the origin 

of hydraulic pressure on such '' pools " ......'..................... 74

2. An ideal geological section illustrating the manner in which petroleum arid natural gas may be concentrated in horizontal beds.... 75

5

NOTES ON THE GEOLOGY OF SOUTHWESTERN IDAHO 

AND SOUTHEASTERN OREGON.

By ISKABL C. RUSSELL.

INTRODUCTION.

<?*

During the summer of 1902 I made a rapid reconnaissance through 

portions of southwestern Idaho and southeastern Oregon for the purpose, principally, of ascertaining in what localities, if any, the geological conditions are favorable to obtaining flowing water by drilling 

wells. This search was more successful than had been hoped, and a 

preliminary report on the artesian basins discovered has already been 

published/' The explorations referred to were in continuation of 

similar work done the preceding summer in southern Idaho, a report 

on which was published as Bulletin No. 199 of the United States Geological Survey. The aim of the present paper is to put on record such 

observations relating to the general geology of the region traversed 

as it is thought may be of interest, more particularly to the people of 

Idaho and Oregon, and also in certain instances serve to supplement 

the report referred to on artesian conditions.

During the reconnaissance I was assisted by Mr. Scott Turner and 

Mr. Robert H. Dawson, students of the University of Michigan. Our 

journey began at Boise, Idaho, on July 6, and ended at the same place 

on September 6, 1902. The route followed was planned so as to 

traverse as many as possible of the valleys of southwestern Idaho and 

southeastern Oregon, in'which rich agricultural land is plentiful and 

where artesian conditions are most likely to be present. Portions 

of Canyon and Owyhee counties, Idaho, and of Malheur and Harney 

counties, Oreg., were examined; but it is not to be understood that 

anything like a geological survey of the immense territory included 

in these counties was undertaken. This paper is simply an account 

of observations made during a rapid reconnaissance, principally in 

the way of supplementing the study of artesian conditions, and should 

not be judged in any other light.

a Water Sup. and Irr. Paper No. 78, U. S. Geol. Survey, 1903.
GEOLOGY OF SW. IDAHO AND HE. OREGON. [BULL 217.

CLIMATE AND VEGETATION.

The leading characteristics of the climate of the portions of Idaho 

and Oregon here considered are: Small precipitation; generally cloudless skies; hot, dry summers; and moderately cold winters, during 

which there is some rain and snow, but not enough to make the mean 

annual precipitation large. Something of the nature of the prevailing 

climatic conditions may be judged from the following data, compiled 

from the report of the United States Weather Bureau for 1900, which 

pertain to localities within or near the region here discussed.

Weather records for the year 1900.

Locality.

Boise, Idaho. . . . .......

Garnet, Idaho ...'..... . .

Pay ette, Idaho ... . ....

Baker City, Oreg .......

Burns, Oreg ............

Silver Lake, Oreg- ...... 

Vale, Oreg -..----......

Precipitation.

Inches. 

12.77 

8.11 

10.60 

13.84 

6,57 

7.34 

9.21

Temperature.

Minimum.

D&j.F. 

11 

14 

10 

-1 

1 

0 

8

Maxi-. 

mum.

Dag.F. 

104

104 

95

99 

98 

101

Mean.

Deg.F. 

52

53.7 

47.3 

46.1 

46.4 

49.4

Killing frost.

Last in 

spring.

Apr. 23

Apr. 26 

Apr. 13 

May 29 

May 1C

(«)

May 26

First in 

autumn.

Oct. 23 

Oct. 25 

Sept. 25 

Sept. 26 

Aug. 8 

(a)

Sept. 18

Snow.

Inches. 

20.1

19.8 

27.8

12.8 

15.5

"Temperature below 82° F. every month.

All the localities mentioned in the above table are situated in valleys. On the mountains cooler and more humid atmospheric conditions prevail. The snowfall is light in the valleys and, like the mean 

annual precipitation, increases with elevation, but not in a direct and 

simple ratio. The general climatic conditions of both Idaho and 

Oregon vary in a conspicuous manner at different localities. In Idaho 

the northern and more mountainous portion of the State is much colder 

and more humid than the intensely arid southern portion. In Oregon 

aridity is the prevailing condition in the southeastern and central 

parts of the State, with increasing humidity toward the west and 

northeast. The portion of each State here described, while characteristic of its most arid valleys and most desolate mountains, must not 

be considered as representative of the entire political division of 

which it forms a part.

The most conspicuous effect of increase in elevation on climatic 

conditions in the region discussed is an increase in precipitation, 

particularly in snowfall. While in spring and early summer the 

snow lingers on the mountains long after it has disappeared from
U. 6. GEOLOGICAL SURVEY

BULLETIN NO. 217 PL. I

MV. vDe>vey

Areas where artesian water 

can probably be obtained...

Boundary of Great Basin, 

or area of interior drainage

Warm and not springs

SKETCH MAP OF PORTIONS OF OREGON AND IDAHO 

SHOWING, APPROXIMATELY, ARTESIAN AREAS

Scale

10 miles
RUSSELL.] CLIMATE AND VEGETATION". 9

the valleys, there is but one mountain range in the region on which 

it remains throughout the year. On Stein Mountain, Oregon, snow 

banks occur in the shelter of northward-facing cliffs in midsummer, 

and severe snowstorms occur as late as the first week in July and as 

early in the autumn as the middle of September. It is principally 

the melting of the usually abundant snow on this mountain range 

that feeds the many streams which flow from it into the adjacent 

valleys!

On account of the small rainfall in the valleys, agriculture is 

impracticable without irrigation. Throughout much of the region 

agricultural pursuits are restricted also on account of the liability of 

frost, particularly in the more elevated valleys where other conditions, 

such as the composition and texture of the soil are favorable.

At one time both valleys and mountains throughout southern 

Idaho and adjacent portions of Oregon were clothed with nutritious 

bunch grass, but now to a great extent these natural pastures are 

nearly ruined, owing to overgrazing. The valleys are treeless, except 

for the occasional cottonwoods along the immediate margins of 

streams, and the hills and lower mountain slopes are for the most 

part devoid of timber.

Throughout southern Idaho and over the greater portion of Oregon 

east of the Cascade Mountains, the plant which is most characteristic 

is the sagebrush (Artemisici). In common with nearly all of the arid 

region of the United States, the area discussed is a sagebrush, land. 

.At no locality along the route traveled is one beyond recognizable 

distance of this ubiquitous grayish-green shrub, except while crossing the barren mud plains left by the desiccation of ephemeral lakes 

or while standing on the summit of Stein Mountain. Although the 

sagebrush imparts a dreary monotony to the valley and lower 

mountain slopes, every traveler who lives out of doors is indebted to 

it for fuel. Not only does the sage replenish the explorer's camp 

fire, but to a considerable extent it is the ranchman's wood pile. 

Where it grows sturdily there is rich land, which needs only irrigation to make it highly productive.

The first -tree to make its appearance when increase in elevation 

brings about greater precipitation is the juniper. Mingled with the 

scattered juniper trees, and usually beginning at a somewhat greater 

elevation than their lower limit, are thickets and groves of mountain 

mahogany. These grayish-green trees when growing wide apart frequently attain a height of 20 to 30 feet and look not unlike olive 

trees. They add much to the beauty of the land, or, perhaps more 

accurately, detract in a marked way from the desolation of the lower 

mountain slopes. In the deep stream-cut valleys they frequently 

form almost iinpenetrable thickets. On many of the lower mountains, 

as Mahogany Mountain in Oregon, for example, they constitute almost 

the only arboreal vegetation. Abqve the lower limit of the juniper
10 GEOLOGY OF SW. IDAHO AND BE. OREGON. [BULL. 217.

and the mountain mahogany in certain favored ranges pines and firs 

appear and occasionally form valuable forests. The scarcity of trees 

throughout the arid portions of the two States visited is indicated by 

the fact that along the route traveled pines and firs are only seen at 

a distance. It is almost literally true that a traveler over the route 

referred to, about 600 miles in length, is never beneath the shade of 

a tree, unless it is one which has been planted and irrigated. The 

Lombardy poplar is usually chosen as a shade tree in villages and 

about farm houses and to serve as a wind-break on the borders of 

orchards and gardens. So adverse to tree growth are the climatic 

conditions that in the region covered by the reconnaissance there are 

only two areas to be seen which are dark with forests.

Castle Rock, a prominent crag situated in the northwest portion of 

Malheur County, Oreg., is on the southern border of an extensive forest of pines, firs, juniper, mountain mahogany, and other trees, and 

from its commanding summit the mountains to the northwest are seen 

to be black with evergreens. In autumn the somber tone of the 

mountains is relieved by dashes of golden yellow, mostly in the gulches 

on the lower mountain slopes, which mark groves of aspens. Again, 

from the hills and mountains near Harney and Burns, in Harney 

County, Oreg'., a splendid forest may be seen mantling the gradually 

ascending mountain to the northwest. It is in this extensive forested 

region that Silvies River has its source. One of the most noticeable 

features of this forest, a part of which has recently, and very judiciously, 

been set apart as a forest reserve, is the absence, so far as can be 

judged from distant views, of burned areas within it. On account of 

the remoteness of the forests of eastern Oregon, from railroads, they 

have not as yet been encroached upon by lumbermen and still preserve 

their primeval beauty.

One interesting feature in connection with the distribution of trees 

on the mountains which rise from an arid region is the occurrence in 

certain instances of two "timber lines." There is an upper limit of 

timber growth, the true timber line, the position of which is determined principally by the severity of the climate and especially by the 

prolonged cold and icy gales of winter. There is also a lower limit, 

determined principally by lack of moisture, below which trees are 

absent. Each of these borders of the mountain forests is in many 

instances sharply defined. On lofty mountains surrounded by arid 

valleys, when seen from a distance, there is frequently present a dusky 

band appearing not unlike the shadow of a cloud, midway up their 

rugged slopes. The band of shade crosses bold crests and deeply 

sculptured valleys, but on both its upper and lower margins is somewhat more extended in the gorges and ravines than on the intervening ridges. The upper limit of tree growth, or the '' cold timber line," 

as it may be termed, as is well known, declines in elevation when 

traced from equatorial toward polar regions.
RUSSELL.] CLIMATE AND VEGETATION. 11

In Mexico the upper limit of tree growth has an elevation of 

about 17,000 feet; in California it has an elevation of approximately 

12,000 feet; on the slopes of Mount St. Elias, in Alaska, it is at an altitude of 2,500 feet; while in northern Alaska and northern Canada it 

reaches sea level. In the far North it becomes the'continental timber 

line, and to the north of it are the treeless barren-grounds and tundras. The lower limit of tree growth, or the "dry timber line," is 

highest where the climate is most arid, and becomes lower and lower 

when traced to regions enjoying greater humidity/' In regions Avhere 

precipitation in the valleys is too scanty to permit trees to grow, the 

mountains may perhaps rise above the lower or dry timber line and 

become forest clothed. If the mountains are sufficiently lofty, they 

may rise above the upper timber line, in which case their summits will 

be bare of trees, but perhaps rendered glorious by fields of gorgeous 

alpine flowers. In regions of extreme aridity the lower limit of tree 

growth, as determined by aridity, may be so high that it meets the 

similar upper limit, as determined by temperature, and even the most 

lofty mountains will be bare of trees from base to summit. A conspicuous illustration of the rise of the lower limit of tree growth until 

it meets the upper limit at which arboreal vegetation can survive is furnished by the White Mountains in western Nevada, which, although 

over 13,000 feet high, are bare of trees from base to summit. In general, then, the mountains of the arid region in west-central North 

America, of which the portions of Idaho and Oregon under consideration form a part, are in many instances bare of trees because they fail 

to reach above the dry timber line; others, in general more lofty, are 

encircled with a belt of forest; while still others, perhaps even higher 

than those having a belt of trees between the two timber lines, are 

barren, for the reason that the dry timber line rises until it meets 

the cold timber line.

These conditions are well illustrated in southeastern Oregon. The 

mountains northwest of Harney and Burns, probably from 5,000 to 

7,000 feet in elevation, are clothed with a fine forest of pines and other 

coniferous trees, while Stein Mountain, about 100 miles distant to the 

southeast, and rising to an elevation of over 9,000 feet, is, Avith the 

exception of scattered groves in the deeper canyons, Avithout trees. 

The mountains north Avest of Burns and Harney are sufficiently .lofty 

to reach aboA^e the lower limit of timber groAvth or the dry timber line, 

and on their higher portions are completely forest clothed, but do not 

have bare peaks rising above the cold timber line. Stein Mountain 

is bare at the summit on account of severe climatic conditions, 

and the region from Avhich it rises is so arid that the dry timber line 

meets the cold timber line, and even an encircling belt of forest is aba There is another condition which at times becomes dominant in limiting the distribution of 

trees, namely, excess of humidity, as on the borders of swamps, lakes, etc., and it may be found 

convenient to recognize a " wet timber line " in addition to those referred to above.
12 GEOLOGY OF SW. IDAHO AND SE. OBEGOiST. [BULL. 217..'-

sent. On Stein Mountain a few pines, firs, junipers, and cotton woods 

grow in the deep canyons on its western slope, and at a few localities 

along the border of the small streams which descend its precipitous 

eastern escarpment. In each of these instances the elevation is well 

below that of the cold timber line, and water for natural irrigation is 

supplied by streams.

The snow line on mountains, or the lower limit of perennial snow, 

Mke the upper and lower limits of arboreal vegetation, is determined 

 by climatic conditions, mainly temperature. The snow line marks 

approximately the elevation at which the mean annual temperature 

is at the freezing point, namely, 32° F. The snow line, like the cold 

timber line, is high above the sea in equatorial regions, and declines 

toward the poles. In the Andes, near the equator, the snow line has 

an elevation of about 17,000 feet; in the high sierra of California, it 

is at an altitude of about 14,000 feet; on the southern slope of Mount 

St. Elias it has an elevation of 2,500 feet; and in the Arctic-Archipelago it reaches sea level. The snow line is higher than the cold 

timber line, and between the two lies the belt of alpine flowers.

In southwestern Idaho and adjacent portions of Oregon none of the 

mountains are sufficiently lofty to reach the snow line, although Stein 

Mountain, the highest and finest range of the region, makes a near 

approach to the necessary height, and, as already stated, snow banks 

are found on its higher portion throughout the summer, but for the 

most part only in the noontide shadow of northward-facing precipices.

TOPOGRAPHY.

The portions of Idaho and Oregon under consideration have broad 

and, in general, flat-bottomed valleys, separated lay abrupt and deeply 

sculptured hills and mountains. The valleys so situated that the 

streams formed in or traversing them can discharge into lower valleys 

or join Snake River are usually trenched by stream channels and 

canyons, but the A^alleys from which there is no escape of the surface 

water are level floored and either contain lakes or the desiccated 

beds of transient water bodies. The valleys for the most part owe 

their existence to the upraising of the bordering hills arid mountains. 

Their generally flat bottoms are due to 'the breadth of the folds or 

irregular dome-like elevations and depressions resulting from movements in the rocks and to the partial filling of the depressions by 

lacustral and stream-deposited debris.

The greatest valley of the region is the one through which Snake 

River flows. This, as was described in a previous report, a extends 

from east to west across the entire width of southern Idaho, and 

includes an area of about 1,200 square miles in Malheur County, Oreg. 

This valley, known also as the Snake River Plains, is underlain by 

lacustral and stream deposits and by extensive sheets of basaltic

a Bull. U. S. Geol. Survey No. 199.
RUSSELL.] TOPOGKAPHY. 13

lava. The fine, light-colored sediments, mostly of Tertiary age, are 

best developed in southwestern Idaho and the adjacent portion of 

Oregon, while the associated lava sheets are more continuous and 

apparently more numerous in southern Idaho east of Ada County. 

This difference in the rocks is accompanied by marked contrasts in 

the topography. The vast smooth plain through which the Snake 

River flows has been deeply trenched by that river from American 

Falls westward, and where the walls of its canyon are of basalt they 

stand in bold cliffs, and if sedimentary beds are present beneath a 

surface sheet of basalt, there occurs along the borders of the plateaus 

a characteristic feature common in many areas in Oregon. The sheets 

of resistant material, with weak strata beneath, give origin to rim 

rocks, as they are locally termed; that is, precipitous and frequently 

vertical escarpments, surmounting more gentle slopes which are 

sheathed with debris derived from the crumbling margin of the protecting layer (PI. XVI). The details in the valley sides present great 

variety, dependent on the number of alternating strong and weak beds, 

and their variations in thickness. Where the strong, resistant rocks 

greatly predominate, the valley sides due to erosion are bold, and if 

canyons have been excavated they are characteristically narrow, with 

nearly vertical walls. Where weak, easily eroded rocks predominate, 

other conditions being the same, the valleys are wide and have flaring 

sides, perhaps with a few vertical steps, marking the positions 'of 

resistant beds, and narrow canyons with vertical walls are absent. 

Where all the rocks cut through in the excavation of a canyon or 

valley are soft or weak, as for example where lava sheets are.absent, 

and only lacustral beds, stream deposits, or beds of volcanic dust and 

lapilli are present, the valleys have widely flaring sides which are 

sculptured-into a great variety of details, owing to the action of rain, 

rills, and usually ephemeral streams. The results just indicated, 

which depend mainly on rock texture and composition, or perhaps 

more strictly on the varying degree of resistance rocks offer to 

mechanical and chemical erosion, are modified, as is well known, by 

differences in the way the earth's surface is being sculptured, 

dependent on climatic conditions, elevation above sea level or the 

base-level of erosion. In the portions of Idaho and Oregon under 

consideration the climatic conditions are essentially the same throughout, but the elevation and the position of the rocks are markedly 

different from locality to locality.

MOUNTAINS.

The entire region here considered may be designated as mountainous, and although at present not enough is known of the underlying 

structure to permit a detailed description of the manner in which even 

the more, prominent elevations were produced, it is apparent that two 

types of mountains are present.
14 GEOLOGY OF SW. IDA.HO AND SE. OREGON. [BULL.217.

The Owyhee Mountains, in southwestern Idaho and the adjacent 

portion of Oregon, consist of a broad dome-shaped mass, composed of 

sheets of igneous rock and thick deposits of Tertiary lake and stream 

sediments, but as indicated by the debris in the stream beds leading 

away from the central part of the extensive uplift, quartzite and 

granitic rocks are present in its higher portion. The great dome, 

from a cursory examination of a part of its bordering slopes, has been 

deeply dissected by streams and given a rough surface.

Similar to the Owyhee Mountains in their general features are the 

mountains of the northern portion of Malheur and Harney counties, 

but too little is known of that region to permit one to speak with confidence, even of the larger features in the structure. It is evident, 

however, that great erosion has taken place, and that all the secondary features, or those which give diversity and picturesqueness to 

the scenery, are due to the weathering of the uplifted rocks and the 

erosive work of streams.

Mahogany Mountain, in the east-central portion of Malheur County, 

Oreg., is a long, narrow, sharp-crested ridge, trending northeast and 

southwest, and presenting a bold escarpment to the northwest and a 

much more gentle, but still steep slope to the southeast. The rocks 

of which it is composed are to a considerable extent, at least, rhyolitic 

tuffs, which occur in well-stratified beds and are resistant to the 

agencies of erosion. Beneath the beds of tuff there are probably soft 

Tertiary lacustral and stream deposits, and the entire series is inclined 

downward to the southeast at angles varying from perhaps 10° to 15°. 

In short, this uplift has the characteristics of the Basin ranges of Utah 

and Nevada, and, as appears from the evidence in hand, may be considered as a ridge produced by the upheaval and tilting of the rocks on 

one side of a break; that is, the mountain is due to the tilting toward 

the southeast of an elevated fault block. Erosion has roughened the 

slopes of the mountain, but not enough to conceal the leading features 

due to uplift. It is clothed with picturesque groves of mountain 

mahogany, whence its name.

The most prominent mountain in eastern Oregon, and by far the 

most conspicuous of all the elevations of a region, embracing many 

thousands of square miles in Idaho, Oregon, and Nevada, is Stein 

Mountain, in the southeastern portion of Harney County. This conspicuous uplift rises to a height of about 9,000 feet above the sea, 

by aneroid measure, and about 5,000 feet above the desert plaj.n in 

Alvord Valley at its east base. It is a long, narrow range, trending 

in general about northeast and southwest, but its crest line is somewhat curved. On the east, in its highest and most characteristic 

portion, it presents a remarkably bold escarpment, and on the west 

it slopes gradually down to the valley in which Harney and Malheur 

lakes are situated. The crest line of the uplift is near its eastern 

border, the descent on the east° being precipitous and seemingly
BUSSBLL.] MOUNTAIN'S. 15

almost vertical, while the west slope, from 20 to 30 miles in length, 

has an inclination varying from- about 3° at the crest line of the 

mountain to less than 1° at a distance of 15 miles, and continuing to 

decrease still, farther westward. Southwest of the highest portion of 

the uplift the rocks of which it is composed are bent into a'broad, 

gentle syncline that widens out to the northwest and passes beneath 

Harney and Malheur lakes. The longer axis of this synclinal trough 

pitches to the northwest and the inclined basin produced by the 

faulting and folding is drained by Donner and Blitzen River.

Stein Mountain is thus a typical monoclinal block of large size. 

The entire length of the uplift is in the neighborhood of 100 miles, 

but its extremities have not been closely examined. It is apparent 

that the main part of the eastward-facing cliff, forming the highest 

portion of the uplift for a distance of over 20 miles, is a fault scarp, 

along the base of which recent movements have taken place, as is 

indicated by the occurrence of hot springs and fresh breaks in alluvial 

deposits. During a visit to this region in 1882 a I believed this fault 

to continue far to the north, but more detailed study must be made 

before this can be considered as fully established. It may be that at 

the north the Stein Mountain fault scarp merges with a similar 

eastward-facing cliff, which may be interpreted as being due to the 

erosion of an anticline. To the east of the great line of cliffs referred 

to there are other monoclinal ridges, which, so far as the evidence 

now in hand is concerned, may be interpreted as remnants of a deeply 

eroded anticline, instead of evidence of extensive faulting, as previously considered.

The rocks of which Stein Mountain is composed are principally 

basalt, in well-defined sheets. The basalt, as is Avell known, was 

poured out in a molten condition, either from fissures, forming what 

are termed massive eruptions, or, what is 'more probable, from welldefined volcanic vents, as has happened in many instances in the same 

general region in recent times. The age of the Stein Mountain basalt 

is probable Middle Tertiary, and it seems to be a part of the great succession of widely extended lava flows, termed in a general way the 

Columbia River lava. In the highest and grandest portion of the 

mountain the layers of basalt are in many instances separated one from 

another by layers of coarse yellowish sandstone, varying in thickness 

from- 4 or 5 to about 15 feet. In one section, obtained while climbing 

the east face of the uplift, which overlooks Alvord Desert, seventeen 

of the sheets of sandstone referred to were observed. The basaltic 

layers average perhaps 60 to 75 feet in thickness, and a large number 

are present. The entire thickness of the great pile of widely extended 

sheets of basalt is about 5,000 feet.

On the west side of Alvord Desert, and for a distance of about 10

aRussell, I. C., A geological reconnaissance In southern Oregon: Fourth Ann. Rept. U. S. 

Geol. Survey, 1884, pp. 431-464.
16 GEOLOGY OF SW. IDAHO AND SE, OEEGON. [BULL. 217.

miles along the east base of the highest portion -of Stein Mountain, 

there are fine exposures of sedimentary rock, mostly shale, beneath 

the basalt composing the main mass of the mountain. These sediments have not, as yet, yielded fossils, but are probably of early Tertiary age. Their exposed thickness is over 1,000 feet. On the west 

side of Stein Mountain, in the vicinity of the east borders of Malheur 

and Harney lakes, there are, again, good exposures of sedimentary 

rocks and of tuff, but these are younger than the Stein Mountain basalt. 

A detailed study of this region can not fail to furnish most instructive results as to the succession of rocks which underlie a great portion of eastern Oregon and the neighboring parts of Idaho and Nevada, 

as well as typical illustrations .of the manner in which the earth's 

crust throughout the same region have been bent and broken and 

otherwise deformed.

Traversing the immensely thick succession of basaltic sheets, in the 

east face of Stein Mountain, there is a number of nearly vertical basaltic 

dikes, ranging in thickness from about 15 to 60 feet. These dikes 

are horizontally columnar in their central portion and are well exposed 

in several instances for distances of a thousand feet or more in the 

walls of nearly vertical cliffs. These dikes, as is well known, are due 

to the filling of fissures with molten rock injected from below. The 

slow cooling of -the intruded magma resulted in producing joints 

which define the sides of the usually six-sided, horizontal columns, 

which forms such a conspicuous feature of the parts of the dikes now 

exposed. The horizontal columns appear not unlike the steps of 

great stairways in the walls of the cliffs traversed by them, and a 

person climbing the mountain finds it convenient to utilize them as 

stepping stones, since in some instances they furnish .the easiest means 

of ascent.

Since the upheaval of 'Stein Mountain it has undergone a large 

amount of erosion, and deep canyons have been excavated in it, 

especially on its western side. From the head of Donner and 

Blitzen River northward to Kieger Creek, a distance of about 25 

miles, each of the principal westward-flowing streams, six in number, 

is situated in a deep canyon of its own making. The boldest and 

most characteristic of these excavations is the one occupied by Kieger 

Creek. This creek has its ultimate source at the crest line of the 

uplift, which, it will be remembed, is on the east margin of the tilted 

block forming the mountain, and flows westward in a steep-sided 

canyon that, for a distance of about 8 miles is over 2,000 feet deep. 

The walls of this canyon, like all the other profound trenches cut in 

the west slope of the mountain, have been excavated in gently dipping 

beds of basalt* None of the westward-flowing streams, however, so 

far as known, has cut through the basalt so as to expose the rocks on 

which it rests. The canyon of Kieger Creek exhibits well-marked 

contrasts on its 'two sides. The north wall is a continuous and
KUSSKLL.] ' MOUNTAINS. 17

remarkably smooth escarpment of basalt, concealed in large part by 

talus, while the south wall is broken by several deep alcoves or side 

canyons, between the mouths of which there are prominent and in some 

instances remarkably picturesque pinnacles and buttresses of black 

basalt. The scenery of the south wall is remarkably fine, and derives 

its principal geological interest from the fact that the bottoms of the 

side alcoves open out into the main canyon to which they are tributary, at a generally uniform horizon, at least 800 feet above its bottom. 

To use a name recently introduced into geographical literature, the 

alcoves referred to are hanging valleys, or valleys which have been 

occupied by and owe their leading characteristics, as is now generally 

conceded, to the work of small glaciers tributary to a much larger ice 

stream. The main canyon of Kieger Greek is broad bottomed, with 

a well-defined U-shape in cross section, due in part, however, to steep 

talus slopes on its side. In brief, the shape of the canyon is such as 

is usually attributed to the work of a stream-like glacier. There is 

an absence of well-marked lateral moraines on the canyon's sides, and 

no polished or striated rock surfaces were observed. In spite of the 

incompleteness of the records, however, it seems safer to conclude that 

the canyon was occupied at one time by a small glacier of the alpine 

type. Four or five small tributaries joined the main glacier on its 

south side, each one being situated in a lateral alcove about 1 mile in 

length. These lateral alcoves have the characteristic shapes of glacial 

cirques, and at the head of each one snow banks at the present time are 

found throughout the summer. With but a slight change of climate, 

prolonging the winter conditions and increasing the snowfall, these 

lateral alcoves would again be occupied by glaciers. There is an 

absence of glacial records on the bold summit portion of the mountain, 

between the deep canyons trenching its gentle west slope, and it 

appears that even during the Glacial epoch the balance of atmospheric 

conditions was only favorable to the accumulation of snow to such an 

extent as to supply small local glaciers in the deeper valleys. Evidently the mountain was deeply trenched by the westward-flowing 

streams before the Glacial epoch, and the canyons excavated at that 

time were subsequently modified in a small way by glacial ice. None 

of the canyons referred to, excepting the one excavated by Kieger 

Creek, was closely examined, but from the descriptions given by residents of the region it seems that several of them, including the one 

in which the principal tributary of Donner and Blitzen River rises, 

may have been modified somewhat by glacial ice. Stein Mountain, 

it will be remembered, is an isolated uplift, and the highest elevation 

in eastern Oregon or the neighboring portions of Idaho and Nevada. 

It is also the only mountain in that great region, so far as we now 

know, that bears evidence of having been formerly occupied by 

glaciers.

Bull. 217 03 2
18 . GEOLOGY OF SW. IDAHO AND SE. OEEGON. [BULL.217.

VALLEYS.

The valleys of southern Idaho and southeastern Oregon are in general broad with nearly flat bottoms and either trenched by stream 

channels or smooth from side to side. The features due to stream 

erosion are found in the vallej^s which have an avenue of escape for 

their waters, such, for example, as discharge to Snake River, but some 

of those which are not completely inclosed are, on account of the 

aridity of the climate, not scored with stream-cut channels. The 

smaller streams from the uplands, on entering a valley, flow less rapidly than in the upper portions of their courses owing, to the flattening 

of their channels. More than this, evaporation decreases the flow, 

and furthermore, also, as the streams enter the arid valleys soil moisture becomes less and there is percolation a^vyay from a stream channel instead of into it, as is normally the case in humid regions. For 

these various reasons the streams drop a large part and in many 

instances all of the material they bring from the uplands, arid thus 

broaden the valley bottoms and tend to give them even surfaces. 

The material brought out of the usually narrow valleys and canyons 

in the uplands and spread over a wide area in the valleys ranges in 

physical character from coarse gravel and even large stones and 

bowlders to fine sand and the finest of silt. The coarser material is 

deposited for the most part near the base of the bordering uplands, 

but under exceptional conditions sometimes is carried far down the 

stream channels, while the finer material, owing to the subdividing of 

the streams in the valleys, and the presence of distributaries on alluvial cones, is spread out over a broad area. By this process deep 

accumulations have been formed over the valley floors. It is to this 

method of deposition that the richness of the soils in the valleys of 

Idaho and Oregon, in common with nearly the entire arid region, is 

due. The streams from the uplands which fail to reach through 

drainage lines to the sea not only deposit their visible loads of Sftlld, 

silt, etc., but their invisible loads as well that is, the material they 

bring from the higher portions of their courses in solution. This 

process is carried on not only by the ephemeral streams, but to a 

considerable extent, as is well known, by the perennial streams, since 

the latter, while flooded, in many instances widely overspread their 

dry-season channels.

In southwestern Idaho and in the northern portion of Malheur 

County, Oreg., the broader valleys are to a great extent floored with 

fine, nearly white silt and volcanic dust the sediment of Lakes Idaho 

and Payette deposited in Tertiary time, and in these instances it is 

sometimes difficult to distinguish the older deposits from the streamdeposited silts laid down on them at a later date. In fact, the material in each instance, to a considerable extent, is essentially the same, 

since modern streams have eroded the Tertiary terranes and redeposited the loads thus acquired on adjacent surfaces.

Throughout many of the valleys of southeastern Oregon the under-
KUSSELL.] VALLETS. . 19

lying formation is fine silt and volcanic dust, essentially the same as 

the material just referred to as having been deposited in Lakes Idaho 

and Payette. Conspicuous examples of such deposits occur in the 

valley of the Owyhee where Jordan Creek enters it, about the eastern 

and southern margins of Malheur and Harney lakes, and in many 

other localities. The picturesque badland sculpturing of the lacustral deposits in the valley of the Owyhee is represented on PL XVIII.

In general, as may be gathered from the statements just made, the 

valleys of the region examined are floored with the deposits of Tertiary lakes and by modern alluvium washed in from the adjacent 

uplands. Another process of filling is through the action of the wind. 

Considerable removal and redeposition of fine material is now going 

on, and in certain localities notable accumulations of sand and dust 

can be easily traced to this cause. Still another process of valley 

filling, which results in giving depressions remarkably level and conspicuously persistent surfaces, is by the accumulation of rock fragments, such as lapilli and volcanic dust blown out of volcanoes during 

explosive eruptions, and the overflow of highly liquid lava from volcanic vents, as will be explained later in describing some of the 

recent volcanoes of the region under consideration.

The wide distribution of fine alluvium over valley floors by ephemeral streams necessitates a delicate adjustment of climatic and 

topographic conditions such as is seldom seen except in regions of 

small rainfall. Before man disturbed the balance of natural conditions, many of the valleys of Idaho and Oregon became deeply filled 

with fine, usually yellowish or nearly white rock debris, and only faint 

stream channels, if any at all, could be distinguished on the surfaces 

of the deposits during the seasons of extreme desiccation. The 

uplands and valleys alike were clothed with an open growth of vegetation, consisting largely of bunch grass. On the uplands and hillsides the grasses serve to bind the soil together, but less completely 

and efficiently than is usually the case in humid regions where a continuous sod is present. In the valleys, owing to the absence in many 

instances of stream channels in the deep alluvium, soil moisture was 

held near the surface at least during a considerable part of the dry 

season, and grasses, notably the coarse rye grass, grew luxuriantly. 

This delicate balancing of conditions, a result of a long period of 

adjustment, was seriously disturbed when stock was introduced and 

grazing on the natural pastures was carried on extensively. The 

introduction of large numbers of sheep, especially, has resulted in the 

nearly complete destruction of the bunch grass over vast areas, and 

in consequence the surface run-off from the uplands has been rendered 

more rapid and rilb have been formed where previously the rain 

water soaked into the ground and percolated slowly away. The 

more rapid surface run-off has caused the hillsides to be deeply 

gullied, much of the soil has been swept into the lowlands, and on 

account of the increased strength of the surface streams the debris
20 GEOLOGY OF SW. IDAHO AND SE. OEEGON. [BULL.217.

taken in suspension and redeposited is coarse as well as more abundant than formerly.- Destructive denudation is thus in process on the 

hillsides and an equally destructive deposition taking place in the 

valleys. Owing'to overgrazing the grasses do not have an opportunity 

to mature their seeds and scarcely to sprout from the old roots, and 

the destruction of the natural pastures is thus for several reasons 

going on at an accelerated rate. One result of the quicker transfer 

of the surface waters from the upland to the valleys is the excavation 

of channels, frequently from 5 to 20 feet deep, in valley floors, where, 

previous to the change referred to, the water spread out over the surface and deposited fine silt instead of eroding as at present. The 

cutting of channels has, in many instances, resulted in a far more 

complete subdrainage of the valleys, and in consequence has caused 

the disappearance of the rye grass which formerly flourished in them 

and its replacement by sagebrush. A conspicuous illustration of the 

process just outlined is furnished in the broad-bottomed valley of 

Willow Creek, northwest of Vale, in the northern part of Malheur 

County, Oreg. This valley, previous to the introduction of stock in 

excessive numbers, is reported to have been without a dry-season 

stream channel, and to have been clothed over great areas with a 

luxuriant growth of rye grass, which was mowed each year for hay. 

Now, owing to the more rapid escape of the rain water falling on the 

upland, a stream channel 8 or 10 feet deep has been excavated for a 

distance of a score of miles through the central part of the valley. 

In summer this freshly cut channel is dry and contains only occasional pools of water, and the rich land adjacent to it is so completely 

snbdrained that the meadows of rye grass have disappeared and been 

replaced by sagebrush.

The cause for the recent changes just referred to is, as stated, over- 

.grazing. The lands that have suffered, but more particularly the

uplands, belong to the Federal Government, and are considered as 

free pastures. The reason for the ruin that has been wrought is the 

greed of the people owning stock. The remedy is the prohibition of 

free grazing on public lands. Now that practically all the land which 

can be irrigated, excepting through the use of artesian water and by 

the construction of storage reservoirs, such as can only be built by 

State or national aid, has passed to private owners, it seems desirable 

that the remaining land, and especially the hills and mountains, 

should be placed on the market at such a figure and under such conditions that they can be acquired in large tracts and cared for as 

private pastures. The beneficial influences of such a system are 

already shown, although illegally and in defiance of Federal laws, 

by the extensive tracts of Government land that have been inclosed 

with fences by numerous individuals and stock companies. If the 

grazing lands pass to private owners the interests of such owners 

would be to decrease and otherwise regulate the degree to which 

they are grazed, and to conserve and regenerate the rapidly vanishing 

grass crop.
KVSBELL.] GEOLOGY OF SW. IDAHO AND SE. OREGON. 21

HYDROGRAPHY.

DRAINAGE SLOPES.

In reference to drainage the portions of Idaho and Oregon traversed 

dining the reconnaissance of 1902 present two principal, divisions. 

All of the part of Idaho visited, together with Malheur County and 

the northeastern part of Harney County, Oreg., belong to the drainage system of Snake River, a branch of the Columbia, the waters of 

which are discharged into the Pacific Ocean. This region is thus a 

portion of the Pacific slope of North America. The.principal part of 

Harney County, however, sends no water to the ocean, but is a part 

of the great region of interior drainage termed the Great Basin. The 

dividing line between these two great hydrographic provinces, in the 

region under review, is indicated by a broken line on the map forming 

PI. I.

STREAMS.

The principal streams tributary to Snake River are the Owyhee and 

Malheur rivers. The Owyhee rises in the bold mountains of Owyhee 

County, Idaho, and the adjacent region on the west which lies in 

Oregon, and has the same general topography and dim ate. It flows for 

the most part through a succession of narrow defiles cut in resistant 

igneous rocks, but at times its canyon opens out into park-like valleys 

where soft laciistral sediment permitted easy excavation. One of 

these wide reaches eroded by the stream is situated where Jordan 

Creek joins it. Here there is a beautiful valley about 6 miles long 

and 2 miles wide, the east and west borders of which are picturesque 

cliffs. The rocks are principally evenly stratified lacustral sediments 

of Tertiary age which are light colored and in part of a delicate-green 

tint. Some idea of the marvelous rain and wind sculpture on the bold 

wall of this little stream-eroded basin may be gathered from PL 

XVIII. The bottom of the valley is sagebrush land, a small portion 

of which is now under irrigation. At the lower end of the valley the 

soft lacustral deposits are absent, and the river has cut a narrow canyon about 200 feet deep with vertical wall through dense igneous rock. 

A favorable site is here furnished for a storage reservoir, in which 

the abundant winter waters of the Owyhee might be retained for use 

on the parched plains near Snake River. This site is certainly worth 

careful investigation by engineers, and as I have been informed by 

settlers in the region, is but one of several similar localities along 

the Owyhee where storage dams might perhaps be constructed to 

advantage.

The Owyhee River, in the lower portion of its course, after passing 

through a narrow, irregular, steep-sided canyon in the Cedar Mountains and emerging into the broad valley excavated by Snake River, 

is bordered by flat lands, where the soil is rich. All of its water in 

summer is used for irrigation.
22 GEOLOGY OF SW. IDAHO AND SE. OREGON. lnuLL.217.

The Malheur River derives by far the greater part of its water from 

its branches, which come in from the northwest and have their sources 

in the forest-covered Strawberry Mountains. Its principal tributaries 

are perennial streams, but in summer all of the water which reaches 

the main channel is used for irrigation along the lower 40 miles of its 

course, and great areas of desirable land still remain uncultivated. 

As in the case of Owyhee, the Malheur demands careful study from 

hydraulic engineers, with the view of storing its winter flow for summer use.

A feature of special geographical interest in the case of the Malheur 

is the fact that it has lost fully one-third of its former drainage basin, 

owing, judged by the observations, to the occurrence of a lava flow 

which dammed its channel in the vicinity of Mule, in Harney County, 

between Stein Mountain and the Crow Creek Hills. It is to this lava 

dam, which obstructs the old river bed for a distance of about 30 

miles, that Harney and Malheur lakes are due. The surface of the 

lava is only about 10 or perhaps 15 feet above the normal level of 

Malheur Lake, but the broad, flat-bottom valley to the west of the 

obstruction permits of the spreading out of the waters which reach it 

until evaporation counterbalances the inflow, and the lakes produced 

have never risen sufficiently to discharge across the lava sheet which 

retains them.

The portion of the former channel of Malheur River now floored 

with a sheet of recent lava is situated about 6 miles north of Mule, 

and leads from the broad basin of Malheur Lake eastward to Camp 

Creek, at present the extreme southern branch of Malheur River. The 

level-floored valley is about 1 mile wide near Mule, with bold bluffs on 

each side, and the essentially level lava sheet now forming its bottom 

is not broken by a stream channel until a point about 6 miles from 

Camp Creek is reached. Near the terminus of the lava stream its

surface is rugged and presents numerous ridges like those so common 

in the Snake River Plains. The valley is treeless, but is covered 

with a strong growth of sagebrush.

The failure of Malheur Lake to rise and overflow the low lava dam 

which confines it is evidence that the climate of the region has been 

arid since the obstruction was formed. The ponding of the waters 

above the lava dam and their failure to rise and cross it caused the 

entire region now drained by Malheur and Harney lakes, aboirt 4,500 

square miles in. area, to be removed from the Pacific slope drainage 

and added to the Great Basin.

The principal streams in the region draining to Malheur and Harney 

lakes are Silvies River, which rises in the forest-covered mountains 

to the north of Burns and Harney, flows south, and empties into Malheur Lake; and Donner and Blitzen River, which has its head branches 

on the west slope of Stein Mountain, flows northward, and also enters 

Malheur Lake. Of these two important streams, Silvies River is 

much the larger. Each of these streams is-utilized to its full capacity
8PBINGS AND AETESIAN WELLS. 23

for irrigation, but there are seemingty favorable conditions for storing 

their abundant winter run-off and thus increasing their efficiency, not 

only for agricultural purposes, but as sources of power. Of the 

numerous small streams which rise on the elevated borders of the 

Malheur-Harney basin, and flow toward its center, there are none 

which reach the lakes in summer. Some of the small streams referred 

to, as Rattlesnake Creek near Harnej7 , and Cow Creek, in summer 

barely enter the broad flat-bottomed basin to which they floAv and 

there expand and are lost in natural meadows. In the majority of 

instances, however, the smaller streams from the mountains flow only . 

during the rainy season or when the snow on the uplands is melting; 

they become dry in summer.

East of Stein Mountain there are several basins, aggregating about 

1,500 square miles in area, from which there is no outflow of water. 

The largest of these is the one in which Alvord Desert is situated. 

Alvorcl, Mann, and Juniper lakes occupy other similar desert valleys. 

This region is a part of the Great Basin, and all the water which 

reaches it is evaporated. The streams are small and wherever land 

is available are fully utilized for irrigation.

Such information as I have been able to gather concerning Snake 

River and. its tributaries, in the portion of its course represented on 

the accompanying map (PL I), is contained in Bulletin No. 199 of 

the United States Geological Survey. A much more detailed account 

of the river, however, and of the water resources generally of southern Idaho maybe found in the reports of the State engineer'of Idaho.

SPRINGS AND ARTESIAN WELLS.

Some account of the warm and hot springs and of the artesian wells 

in the portions of Idaho and Oregon examined in 1902 has been presented in a preliminary report on the work of that season/1 and only 

a brief summary of the results reached in this connection seems 

desirable at this time.

It is to be understood that the streams briefly described above, like 

most streams the world over, are fed by rains or melting snow, but to 

a great extent owe their water supply to seepage from the bordering 

uplands. The seepage referred to is sometimes sufficiently concentrated at definite localities to form hillside springs, the temperature 

of which throughout the year is approximately the same as the mean 

annual temperature of the locality where they are situated. In the 

region under consideration this may be taken as approximately 50° F., 

although in certain localities, as at Burns, Oreg., it is perhaps 2° 

lower.

In addition to hillside springs, there are at numerous localities, as 

indicated approximately on the map (PL I), springs of warm or hot 

water, which rise from deep sources, presumably in most instances

« Water-Sup, and Irr. Paper U. S. Geol. Survey No.- 78,1903.
24 GEOLOGY OF SW. IDAHO AND SE. OEEGON. [BULL.217.

through fissures. These springs range in temperature from a few 

degrees above the mean annual surface temperature up to the boiling 

point of water for the elevation at which they occur, and vary in 

volume from a mere seepage to several cubic feet per second. Good 

examples are furnished in Idaho \yy the hot springs about 44 miles 

east of Boise, the hot spring about 7 miles east of Mountain Home, 

the warm spring 1 mile west of Walters Butte, the copious hot spring 

at Enterprise, and the several springs of warm water near Sands. Ill 

Oregon hot springs occur at Vale, where one has a temperature of 

198|-0 F., so far as known the hottest in the region; in Warm Spring 

Valley between Vale and Westfall; at Beulah; from 1 to 3 miles 

southwest of Burns; near Silver Lake; on the southeast border of 

Harney Lake; a fe^smiles northeast of Malheur Lake; in Alvord 

Valley on the west border of Alvord Desert; near Andrews; and in 

Whitehorse Valley. Such data as are available concerning these 

numerous fountains of heated waters are presented in the Preliminary 

Report on Artesian Conditions,^ already referred to.

The chief interest in reference to these warm and hot springs 

aside from their direct utilization for irrigation, baths, cooking, 

warming houses, etc., is the bearing they have on the question of 

obtaining artesian water. Every fissure spring is essentially a natural 

artesian well, but in most instances the conduits through which the 

water rises are obstructed and much lateral flow or leakage presumably results. The question as to the best way of improving such 

springs and of increasing their flow presents itself to everyone who 

examines them. In a few instances'efforts have been made in this 

direction which are highly promising. Wells drilled in the vicinity 

of the hot springs near Boise have been conspicuously successful, and 

the capital of Idaho now has an excellent supply of both hot water 

temperature from 125° F. to near boiling point and of water with a 

temperature of from 60° to 70° F. derived from artesian wells. Other 

successful artesian wells have been drilled in the vicinity of hot 

springs in Bruneau and Little valleys, Idaho, and again at Vale, 

Malheur County, Oreg. The well at Vale is, however, not utilized 

except for bathing, on account of the large amount of mineral matter 

in solution, much of which is deposited in the casing of the drill hole 

and leads to its obstruction.

The water of this artesian well, or, perhaps more accurately, developed hot spring, should be analyzed in order to learn its medical or 

other properties, and experiments made with reference to preventing 

the precipitation of mineral matter. The precipitation is apparently 

due to the cooling of the water as it rises, and by insulating the casing this could no doubt be decreased and perhaps prevented. Then, 

too, if the waters prove of value, tools for cleaning the well could 

easily be provided and the obstructions formed within it removed as 

frequently as necessary.

a Water-Sup, and IIT. Paper U. S. Geol. Survey No. 78,1903.
HYDROGRAPHY. 25 

ARTESIAN BASINS.

The study of the geological structure that is, the positions the 

stratified rocks occupy together with the information furnished by 

springs and drilled wells, has shown that there are four basins in 

southwestern Idaho and southeastern. Oregon which may be expected 

to yield flowing water when wells are put down. In two of the basins 

referred to drilled wells have already proved the presence of subsurface water under sufficient pressure to cause it to rise to the surface 

and overflow when the drill holes are properly cased. The four basins 

referred to have been described in the Preliminary Report on Artesian 

Conditions already mentioned, and are indicated approximately on 

the map forming PI. I. They have been named the Lewis, Otis, 

Harney, and Whitehorse artesian basins. Their combined areas below 

the artesian head in each instance is estimated at approximately 2,000

square miles. While it is not to be assumed that all of this area can 

be irrigated Dy means of artesian wells, the conditions are such as to 

warrant the careful testing of each basin and a judicious development 

of its water supply.

The Lewis artesian basin, situated along Snake River, between 

Glenns Ferry and Weiser, and including Bruneau and Little valleys 

and the lower portion of Boise Valley, has an area below the known 

artesian head of not less than 1,000 square miles. Wells have been 

put down in it at several localities, as in Bruneau Valley, Little Valley, and near Guffey, Central, and Enterprise, in Idaho, and at Ontario, in Oregon. These wells are from 200 to somewhat more than ] ,000 

feet deep, and with one exception near Central are all successful so 

far as demonstrating the presence of artesian conditions is concerned, 

and in the majority of instances furnish a strong surface flow of 

water. The water in all cases in. which temperature measurements 

have been made is warm and in general ranges from 60° to 100° F. The 

exceptional well at Vale, which is strictly speaking a developed hot 

spring, has a temperature of 198-^° F. The artesian wells near Central 

and Enterprise exhibit an increase in their temperature gradients 

that is, the rate of increase in temperature with depth as the large 

hot spring at Enterprise is approached. This and other similar 

although less definite instances indicate that the Lewis artesian basin 

is supplied in part at least by water rising through fissures from a 

considerable depth.

. The greater number of borings that have been put down in the 

Lewis artesian basin were drilled with the hope of obtaining petroleum. 

In this respect they were failures, although they attained a more desirable result in demonstrating the existence of artesian water. The 

reasons for the failure to discover petroleum and the conditions which 

lead to the accumulation of that substance will be discussed later.

The Otis artesian basin, in the region drained by Otis Creek, about 

6 miles northeast of Drewsey, Oreg.. has not been tested with the 

drill, and will merit the name here given it only after such demon-
26 . GEOLOGY OF SW. IDAHO AND SE. OEEGON. [uuLL.217.

stration. The reasons for predicting the presence of subsurface water 

under pressure are the basin-like structure the-rbcks exhibit and the 

presence within the basin of strong springs of warm water. The area 

throughout which it is probable that artesian water can be had is in 

the neighborhood of 20 square miles.

The Harney artesian basin embraces the extensive region draining 

Malheur and Harney lakes, and as shown by its geological structure may be expected to yield flowing wells throughout an area of 

perhaps 1,000 square miles. Two drill holes, one near Harney and 

the other near Burns, have been put down and have demonstrated 

the existence of subsurface water under sufficient pressure to force it 

to the surface where wells are drilled to the requisite depth" and properly cased. The artesian head, as indicated by these wells, has an 

elevation of about 4,100 feet. The thickness of rocks involved in the 

formation of the basin, however, probably exceeds 10,000 feet, and 

water-bearing horizons at a greater depth than those now known may 

reasonably be expected to be present. Several warm and hot springs in 

the Harney basin, as already mentioned, lend support to the prediction 

that success will follow a careful exploration of the basin with the drill 

where the surface elevation is less than that of Harney or Burns.

The Whitehorse artesian basin is located about 20 or 25 miles east 

of the higher portion of Stein Mountain, and includes the valley in 

which the former military post known as Whitehorse was located. 

Here again the geological structure and the presence of warm springs 

are sufficiently strong indications to warrant a careful exploration 

with the drill with the hope of obtaining a surface flow of water. The 

artesian head, as shown by the warm springs about 6 miles south of 

Whitehorse ranch, is well above the flat lands of the valley's bottom. 

The area throughout which one is seemingly justified in predicting

success in case wells are drilled Is not less than 30 square miles.

The four artesian basins briefly described above contain about 2,000 

square miles of rich agricultural land, throughout which the conditions justify the opinion that flowing water may be obtained. It does 

not follow from this that all or even the greater part of the tracts 

referred to can be irrigated, as it is to be presumed that the water 

supply will not be adequate to meet all the dema,nds that will be 

made upon it. The expense involved in drilling a well, and. the 

certainty that the water supply even under the most sanguine 

expectations which may seem warrantable is not inexhaustible, make 

it imperative that there should be the strictest economy in the use 

of the water and rigid restrictions with reference to its waste. Suggestions in this direction have been offered in the Preliminary Report 

on Artesian Conditions, to which the reader is referred for a more 

detailed record of the facts available concerning the artesian basins 

of the region under review and the best means to be employed in the 

development and care of their water resources.
RUSSELL.] HYDROGRAPHY. ' . 27

LAKES.

As previously stated, the portions of Idaho and Oregon shown on 

the accompanying map (PI. I) have undergone long erosion, since 

the youngest of the more extensive, geological formations occurring 

there were spread out as lacustral sediments or lava flows, and during 

or since these same formations were folded and faulted. As a result 

of such a well-advanced stage in topographical development, the land 

would be expected to be well provided with drainage channels, cascades and waterfalls should be rare, and all lake basins should have 

been either filled with sediment or drained on account of the cutting 

of channels by their overflowing streams. These expectations are fulfilled throughout the greater part of the region referred to, and the 

exceptions are due to special occurrences which are seemingly accidents, and which have interrupted the normal course of events. The 

SO-Called accidents referred to are of t\vo classes, namely, lava flows, 

and decrease in precipitation accompanied by an increase in the rate 

of evaporation. Locally conditions dependent on each of these causes 

have acquired control in the processes of stream erosion and denudation, and lakes appear in situations where they would otherwise be 

absent.

There are three localities in the region under consideration where 

lakes are present, all of which are in Oregon. These are on Cow 

Creek, a branch of Jordan Creek, in the eastern part of Malheur 

County, where the Cow Creek lakes are situated; the Harney Valley, 

in Harney County, which is occupied in part by Malheur, Harney, 

and Little Silver lakes; and Alvord Valley, also in Harney County, 

and east of Stein Mountain, where there are about 8 lakes during rainy 

periods, most of which evaporate to dryness during summer seasons.

COW GREEK LAKES.

In the valley of Cow Creek, about 12 miles northwest of Jordan 

Valley village, there are several small lakes, with markedly irregular 

outlines. These lakes are due to the damming of the waters of Cow 

Creek by recent lava flows. As will be described later, not less than 

four small volcanic craters of recent origin, which it is convenient to 

term the Jordan Craters, occur in what was previous to their formation 

a well-drained valley. The craters referred to are situated approximately on a north-south line, a little to the west of the former course 

of Cow Creek, and from each crater have been poured out what may 

be truthfully stated to be immense lava flows, in comparison with the 

size of the craters from which they came. Each of these flows acted 

as a dam to the waters of Cow Creek and led to the formation of one or 

more lakes. The most characteristic example of the lakes formed in 

this way is the most northerly in the series, which is held in check 

by the last lava flow from the Jordan Craters. . This lava sheet has an-
28 GEOLOGY OF SW. IDAHO AND SE. OKEGON. [BULL.217.

area of about 50 square miles and entered the'channel which Cow 

Creek had eroded through a previous lava sheet. The recent lava 

flowed up the old canyon for about a mile and now terminates with 

a low, irregular slope. The lava forms a dam, above which a lake 

about 4 miles long has been caused to form. The lake extends into 

lateral valleys so as to have an irregular outline, but on an average 

is perhaps half a mile wids. During high-water stages it overflows 

across basalt and supplies other lakes to the south. In summer it is 

lowered by evaporation, leaving broad areas exposed about its eastern 

and northern borders. These lands are covered with wild grass, and 

form natural meadows from which several hundred tons of hay are 

cut each year. The la,ke has never been known to evaporate to dryness, and is only slightly alkaline. Its water, as is common with 

many playa lakes (that is, lakes which evaporate each summer so as to 

leave large portions, or as is most common, their entire beds, exposed 

as mud plains or play as), is always turbid with fine silt in suspension.

South of the lake just described, which is the largest of the sei'ies 

of which it is a member, there are seven or eight other similar water 

bodies and several small ponds. The irregularities of these lakes and 

ponds and their indefinite or rather variable number are due to the fact 

that the water fluctuates in volume, and as the surface of the lava, 

which is in part submerged, is irregular, marked changes in the outlines and in the number of lakelets to be seen occur between the rainy 

and-dry seasons. The more southern of the Cow Creek lakes, like the 

one at the north, fluctuates greatly in volume, and in summer leaves 

broad natural meadows exposed on its eastern border, from which 

large quantities of naturally irrigated wild grass are cut each year. 

Cow .Creek, south of the lakes in which it is ponded, flows through an 

irregular, ill-defined channel, and near Jordan Creek its waters are 

utilized for iiTigation.

About the Cow Creek lakes the creek which supplies them flows 

through a rather deep canyon which is joined by well-defined branches, 

thus demonstrating that the process of stream adjustment and of erosion was well advanced before the Jordan Craters sent out lava which 

invaded the medial portion of the valley it entered, and buried its 

previous stream-sculptured surface.

The Cow Creek lakes furnish a fresh and unmodified illustration of 

the effects of lava flows on drainage, and present typical examples of 

lava-dammed lakes. Other lakes of the same character occur about 

the Diamond Craters, at the west base of Stein Mountain, in Harney 

County, but are much less extensive, and in fact swamps instead of 

open water mark the presence of obstructions to the escape of, the 

surface waters. The Bowden Crater, as will be described later, also 

sent out a broad lava sheet, which obstructed the drainage and caused 

a lake to form, but in this instance the outflowing stream has cut a 

drainage channel, and the lake, which once existed, has been drained.
EUSSELL.] LAKES. ; . . 29 

MALHEUR AND HAKNBY LAKES.

These two water bodies, situated in the central part of Harnejr 

County, present several features of geographical interest. Harney 

Valley-is situated in an arid climate, and is 'one of the many valleys 

in the region of interior drainage termed the Great Basin which now 

fail to send streams to the ocean. Malhenr Lake is flat bottomed, 

with low, indefinite shoi'es, and although fluctuating greatly in area 

with seasonable changes in precipitation and the rate of melting of 

snow on the neighboring mountains, is probably at no time over 10 

feet deep in its deepest part. When most broadly expanded it is 

about 23 miles long by 5 or 6 miles wide and has an area of approximately 135 square miles, but as it is bordered on nearly all sides with 

swamps, and large areas even in its central parts are occupied by 

rank growths of tnles and other aquatic plants, its precise area would

be difficult of determination even if surveys were made for that purpose. Its water supply comes mainly from Silvies River, which rises 

in the forest-covered mountains to the northwest and has a length, 

not including its minor bends, of about 75 miles, and from Donner 

and Blitzen River, the sources of which are on Stein Mountain, 50 or 

60 miles to the southeast. Before their waters were utilized for irrigation these streams probably never failed, even in summer, to send 

a large volume of water to the lake. In addition, there are several 

streams which reach the lake only in winter, and a few springs, which 

add in a small Avay to the lake's resources.

Harney Lake, situated southwest of Malheur Lake, is rudely circular, with a diameter of about 10 miles and an area of from 50 to 60 

square miles. Its northern and western shores 'are low and gently 

sloping, but the water line is well defined, and swamps are absent. 

On the southeast side of the lake cliffs rise precipitously from its 

margin during high-water stages, and near the shore the waters have 

a considerable though as yet unmeasured depth: Judging from the 

appearance of the lake when seen from adjacent hills, and from the 

ineffectual attempts to sound it made by fishermen, it is to be expected 

that a depth varying from 50 to 100 feet throughout a large portion of 

its central and. southwest portions will be discovered when an accurate survey is made. A large volume of water is contributed to the 

lake by Silver Creek, which in midsummer, when its supply conies 

entirely from springs in the lower portion of its course, discharges 

about 10 cubic feet of water per second. In winter and spring Silver 

Creek is greatly extended head wards and becomes a drainage channel 

for a region 80 or 100 square miles in area. At such times it is a 

veritable river with a broad, swift current, and discharges a great 

volume of water into the lake at its mouth. . There are also ephemeral 

streams which flow to Harney Lake during the rainy season, and hot 

springs on its border make some contribution to its water supply.
30 GEOLOGY OF SW. IDAHO AND SB. OEEGON. [BULL.217.

None of the springs rising in the neighborhood of Malhenr and 

Harney lakes, it may be noted, are highly charged with mineral matter in solution, and all their tributary streams are of clear, sweet 

water, unless it is in late summer, when they are greatly reduced in 

volume by evaporation.

Malhenr and Harney lakes are without outlet, except that during 

high-water stages'the former sometimes overflows into the latter 

through a recently formed channel. The two'lakes during their winter 

stages are separated by a narrow irregular ridge of sand dunes, which 

extends westward and borders Harney Lake for several miles. These 

dunes are composed of quartz sand, blown up from the shore of the 

lake during low-water stages by the prevailing westerly winds, and 

make a conspicuous range of hills in general about 100 feet high, 

in part grass covered, with steep-sided basins among them. Previous 

to the formation of these hills of wind-drifted sand the basins of Malheur and Harney lakes were not separated one from the other, at least 

during high-water stages, and but one lake existed. The water in this 

lake at the locality where the basin is now divided was shallow and 

during summer seasons, or at intervals of unusual desiccation, the bottom was exposed. During such a low-water stage, as seems evident, 

the winds drifted the exposed sands and formed a ridge which divided 

the preceding water body into two lakes. This was before white men 

visited the region. It is reported that during an unusually high-water 

stage in 1877, and aided, as I have been informed, by a furrow plowed 

for the purpose, the water of Malheur Lake broke across the ridge of 

sand referred to above and rapidly scoured out a channel leading to 

Harney Lake. This channel is now about a quarter of a mile long, 

30 to 40 yards wide, and from 6 to 10 feet deep. At the time of my 

visit, August 6, 1901, the channel was dry and the water of Malheur 

Lake had shrunk until only a few hundred acres to the south of The 

Narrows (a constriction in the lake near.its southern end, now crossed 

by a bridge) were flooded; the water of Harney Lake had also been 

diminished by evaporation so that the lake's surface was from. 8 to 10 

feet below the ridge of sand and gravel marking its preceding winter 

stage. The gravel ridge or beach line referred to was about on a level 

with the highest point in the newly formed channel, but the ridge, it 

will* be understood, marks the upper limit of the waves generated during storms arid not the usual level of the lake. In summer, when Malheur Lake is low, nearly the whole of the portion of its basin south of 

The Narrows is dry and converted into a play a over which broad areas 

are white with alkaline salts, or overgrown with the familiar plant of 

alkaline valleys known as Salicornia (PL II, A). Nearly every winter 

season, as I have been informed by persons living in the vicinitj^, 

Malheur Lake rises and overflows into Harney Lake. Each lake is 

alkaline, but, owing to the delicate adjustment described above, Harney Lake is more strongly charged with mineral matter in solution
U. S. GEOLOGICAL SURVE

A. SOUTH SHORE OF MALHEUR LAKE, OREGON. SALACORNIA GROWING IN

ALKALI.

11. EOLIAN MOUNDS ON BORDER OF PLAYA, NEAR IRON MOUNTAIN, OREGON.
KUSSELL.J. LAKES. '31

than its companion which occasionally discharges into it. A sample 

of water from Harney Lake collected August 5,1902, gave the following results on analysis:

Analysis of tli,e ivater of Harney Lake, Oregon.

[Analyst. George Steiger.]

Parts per 

million.

Silica, SiOj................. .............................. 28.7

Aluminum, AL........................................... None.

Iron. Fe.----...-......-..... ........... .................. None.

Magnesium, Mg ....--.....--.....-... ^.'.. 1................ 6.8

Calcium, Ca ................................................ None.

Sodium, Na .................. .'.......................... 3,604.5

Potassium, K................................ .............. 192.8

Carbon trioxide, CO3 .............. ... ......... ........... 2,974.7

Hydrogen, H (required in formation of bicarbonate) ...... 32.3

Sulphuric anhydride, SO^................................. 773.3

Chlorine, Cl...................................:.......... 2,771.3

Bromine, Br..--.-.-.-.....--........-.-..-.-.--...-.--.... None.

Iodine, I.................................................. None.

Boracic acid, B4O7 .-.......-..-...-..---...-.------- -.--.. 92.8

Total........................................."...:.. 10,477.2

Specific gravity, 1.081.

NOTE. Reaction strongly alkaline. The computation shows that no free carbonic acid is present above that required to form bicarbonates.

Judging from the analysis given above, the most abundant salts 

contained in the lake waters are sodium chloride or common salt, 

sodium carbonate or bicarbonate, and sodium sulphate. Potash and 

borax are present, but as the total amount of saline matter in solution 

is only 1.04 per cent by weight, the lake waters can not be considered 

as being of commercial value. The low degree of 'salinity, and the 

absence of iodine and bromine, together with the low percentage of 

magnesia, furnish evidence that the lake as it exists at the present 

day is not the result of a long period of concentration by evaporation.

The water of Malheur Lake is a weaker saline solution than its companion, as it is being freshened by overflow. While this renders it 

evident that it is of no economic importance, so far as. its contained 

salts are concerned, it is of interest in reference to the proposed use 

of its water for irrigation, as it is not too highly saline for that purpose. The manner in which Malheur Lake is contributing its. salts 

to Harney Lake, by the process of occasional overflow described 

above, is also of much interest to geologists, as it illustrates one 

method by which a Jake may be freshened, while at the same time a 

companion lake is growing more and more saline. a

« The occasional outflow of water from Malheur Lake into Harney Lake, from which it escapes 

solely by evaporation, is a counterpart on a small scale of the process, now well advanced, by 

which the Caspian Sea Is being relieved of a part of the saline matter it holds in solution. The 

Caspian is an inclosed lake, 181,000 square miles in area, the waters of which vary in chemical 

composition in different parts, but remote from the mouth of the Volga and other tributary 

streams contain 0.6494 per cent of total salts in solution. On the east side of the Caspian there is
32 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BULL.217.

The inner slopes of the valley in which Malheur and Harney lakes 

are situated are not scored with old beach lines or terraces, as is thecase in so many of the similar valleys of the Great Basin. This is 

consistent with the low elevation of the old river channel leading 

eastward from the valley to the headwaters of Malheur River. As 

already stated, the present hydrographic basin of Malheur and Harney lakes was formerly a part of the Malheur River drainage system, 

and was cut off by a lava flow which entered the channel of the former 

and greater Malheur River. On account of the small precipitation 

and active evaporation in the region above the broad lava dam, the 

water in the basin thus cut off has never been able to rise sufficiently 

to cross the obstruction which retains it. The evidence thus furnished, 

tending to show that Malheur and Harney lakes are not remnants of 

a former large water body, is also in harmony with their chemical 

composition. Their present degree of salinity indicates but a comparatively short period of time since the dam which retains them was 

formed. The lava sheet referred to is, however, covered with a thin 

soil, and supports a rank growth of sagebrush, indicating that it is 

much older than the very recent lava flows about the Diamond, Bowden, and Jordan craters, to be described later. -

SILVER LAKE.

In the valley of Silver Creek, about 11 miles northwest of Harney 

Lake, there is a small, shallow water body, termed Silver Lake, and 

sometimes referred to as Little Silver Lake to distinguish it from 

another and larger water body of the same name situated in Lake 

County, Oreg. The basin in which Silver Lake is situated is broad 

and flat, with indefinite boundaries, and during high-water stages 

becomes a wide expansion of the creek which flows through it. In 

summer the creek ceases to flow, and the lake is kept from evaporating to dryness by the contribution received from a hot spring on its 

southern border.

Several basins along the somewhat indefinite course of Silver Creek 

between Silver and Harney lakes become flooded in winter and completely desiccated in summer. When dry the floors of these shallow 

basins become absolutely'barren mud plains or playas, some of which 

are 3 or more miles across. These yellowish floors of dried mud are 

sufficiently hard in summer to be crossed with a loaded wagon withabay, about 100 miles in diameter, known as the Karaboghaz, or "bitter lake," which is connected with it by a strait 450 yards wide and 5 feet deep. The Karaboghaz has no inflowingstreams and no outlet. The climate is arid, and on account of the loss from its surface by evaporation a current sets into it from the Caspian at a rate of from l£ to 3 miles per hour. As computed by Van Baer, the amount of saline matter carried by this current is 330,000 tons per day. 

The Caspian is thus losing saline matter probably at a greater rate than it is being supplied, and 

the water of the Karaboghaz has been concentrated to such an extent that it is a saturated 

solution, and contains something like 24 per cent of saline matter, and from it common salty is 

being deposited. An instructive example is thus furnished of one method by which a saline 

lake may be relieved of its salts, and of one method also by which saline matter is concentrated 

and deposited in a solid form.
RUSSELL.] LAKES. 33

out leaving more than a faint trail. Their smooth surfaces are usually 

intersected in every direction by a network of shrinkage cracks, and 

about their borders there is in some instances a white incrustation of 

saline matter, which is left as the water which seeps down from the 

neighboring uplands is drawn to the surface by capillary attraction 

and evaporated. The characteristic vegetation about the borders of 

these and many other similar playas in the Great Basin region is the 

common greasewood. This shrub frequently attains a height of 4 to 

6 feet, and, like most desert plants, grows in isolated clumps. These 

. bushes encroach on the playas, and occupy an advanced picket line, 

where the conditions leading to survival or death are nearly evenly 

balanced. One result of this delicate adjustment is that during the 

periods when the playas are desiccated the wind blows away the dried 

sediment from between the clumps of bushes, and also drifts fine 

de'bris about them, so that rudely circular mounds are formed, which 

in many instances are 8 or 10 feet high and from 12 to 20 feet in diameter. (PL II, B.) The roots of the greasewood serve to retain the 

material forming the mounds, and the obstruction to the wind afforded 

by their branches also tends to preserve them. That the mounds are 

dependent on the greasewood for their preservation is well shown by 

the fact that when the bushes die the mounds soon disappear. In 

some instances a complete sequence can be observed, from large 

mounds crowned with a vigorous growth of greasewood through similar mounds on which the bushes are dead, and from those to others 

partially denuded by the wind, in which only the roots of the plants 

which formerly grew in them can be found, and from these again to 

low, indefinite hillocks on the desert, and even flat, circular areas 

which reveal the former presence of a mound solely by the fact that 

the surface is slightly softer and perhaps a little more moist than the 

broad, flat area about it. Although greasewood mounds of the nature 

just described are seemingly transient features of the borders of 

playas, they might, in certain situations, survive a change to more 

humid climatic conditions and the areas they occupy, becoming grass 

covered, be transformed into "mound prairies."

THE LAKES OF ALVOKD VALLEY.

At the foot of the precipitous eastward-facing escarpment of Stein 

Mountain there is a well-defined valley, trending in general about 

northeast and southwest, which is fully 75 miles long, and about 8 

miles wide in its widest part. This valley was evidently at some 

former time a part of a river system, but the topgraphic history of the 

extensive region of which it is a representative part remains to be 

deciphered.

In the widest part of Alvord Valley, and east of the highest portion of Stein Mountain, is situated Alvord Desert. This is a mud 

plain or playa throughout most of the year, but in the winter and 

Bull. 217 03 3
34 GEOLOGY OF SW. IDAHO AND SE. OKEGON. [BULL. 217.

spring it becomes covered with a few inches or possibly 1 or 2 feet of 

water and transformed into a lake, which when f iilly expanded covers 

an area of between 50 and 60 square miles. The water supply for 

this winter lake is furnished principally by the small streams which 

descend the precipitous east face of. Stein Mountain, but a small contribution is made by a hot spring on its southwest border. In summer the desiccated bed of the lake is a smooth, even, hard mud plain, 

crossed in every direction by a rather fine network of small shrinkage 

cracks. Scattered over the smooth and frequently glossy surface 

there are, at intervals usually of several rods, fragments of rock, some 

attaining a diameter of perhaps an inch. The manner in which these 

angular fragments reached their present resting place is obscure, but 

it is probable that they were transported and deposited by floating 

ice. Frequently on clear, hot summer days the delusive effects of 

the mirage relieve the desolate monotony of the desert and the surface is seemingly flooded with water. To the south of Alvord Desert 

and in the same valley or basin is another and smaller playa lake, 

known as Alvord Lake, which is supplied during the wet season by 

Trout Creek, and also receives the waters from a constantly flowing 

hot spring.

North of Alvord .Desert the valley adjacent to the east base of 

Stein Mountain becomes narrow, its general width being about 2 miles, 

and the streams from the bordering mountains have deposited large 

alluvial cones, some of which extend entirely across the depression 

and meet the debris on its eastern side. In this manner the valley 

has been divided into a number of shallow basins, four of which hold 

small playa lakes, of which Juniper and Mann lakes are representative examples.

The basin in which Juniper Lake is situated was formerly more 

deeply flooded, as is shown by beach lines about its borders, and contained a lake about 7 miles long, 2 to 3 miles wide, and 100 feet deep. 

About the little valley in which Mann Lake occurs there are also 

faint beach lines which show that it formerly contained a lake 

approximately 150 feet deep and about 4 miles long and 2 miles wide. 

Several of the small basins between the sharp-crested ridges to the 

east of the two lakes just mentioned are occupied by mud flats in 

summer and by ephemeral lakelets in winter."

FLUCTUATIONS OF LAKES AND EFFLORESCENCES.

The lakes of Harney and Alvord valleys, and other places described 

above, are similar in many ways to a large number of lakes scattered

a As the facts concerning a few of the inclosed lakes of Oregon here presented may perhaps 

lead the reader to wish to continue the study further, references are given to some of the more 

accessible reports, books, etc., bearing on the subject:

Russell, I. C., Geological history of Lake Lahontan: Mon. U. S. Gieol. Survey, vol. 2,1885.

Russell, I. C., Quaternary history of Mono Valley, California: Eighth Ann. Kept. U. S. Geol. 

Survey, 1889, pp. 261-394.

Gilbert, G. K, Lake Bonneville: Mon. U. S. Geol. Survey, vol. 1,1890.

Russell, I. 0-., Lakes of North America, 1895.
RUSSELL.]- LAKES. 35

throughout the Great Basin, "but occurring principally in its northern 

half. The reason for the presence of more lakes in the valleys of the 

northern than in similar inclosed basins in the southern part of the 

Great Basin, is evidently due principally to a slightly greater mean 

annual precipitation and a slight decrease in evaporation as one 

journeys from the south toward the north in that region. The 

lakes of southeastern Oregon furnish an instructive contribution to 

the study of -the delicate balancing of conditions referred to, and 

illustrate the manner in which mountains may become the controlling 

condition on which depend the existence of the lakes in neighboring 

valleys. For example, if mountains had not been upraised about the 

Harney Valley to act as condensers and give origin to streams, it is 

evident that the basins of that region would not have had lakes 

developed in their deeper portions.

Another feature in which the portion of Oregon here considered is 

representative of the Great Basin in general is the deep filling in the 

valleys. In a region which has no outflowing streams, all the material brought from the bordering or included uplands and mountains 

by the rain wash, rills, brooks, etc., is deposited in the valleys. For 

this reason, the depressions normally become deeply filled with streamdeposited alluvium and with the sediments spread out in lakes. 

These two processes of deposition are frequently in operation at the 

same time, and it is extremely difficult in many instances to determine frcmi a study of the accumulations whether they were made by 

flowing or by still water. In general the valleys throughout the 

Great Basin have been deeply filled with fine silt-like material having 

a light-yellow color, deposited in part by streams and in part in lakes. 

The vaJleys have thus been given nearly level floors in their central 

parts, and on their borders slope upward in gentle curves to meet the 

bordering hills and mountains. This is the case in the Harney and 

neighboring valleys, and the surface deposits of fine silt form rich 

soil, which needs only water to make it highly fruitful.

In a region devoid of outflowing streams all of the material brought 

to the valleys by streams in solution their "invisible loads" as well 

as all of the debris they carry in suspension their visible loads is 

left as the waters evaporate. Hence not only the lakes of such regions 

are characteristically alkaline, but the soils are apt to contain easily 

soluble salts. Within each inclosed basin there is an assorting and 

concentration of saline matter, and as frequently happens the lower 

lands are strongly alkaline. At times, as the waters evaporate, surface incrustations or efflorescences are formed, consisting principally 

of common salt, sodium sulphate, sodium carbonate, Qtc., but in rare 

instances they also contain boracic acid, and are valuable as sources 

of borax.

Several of the small playas in southeastern Oregon are covered in 

summer with white incrustations of the nature just described. A
36 GEOLOGY OF SW. IDAHO AND SE. OREGON. '[BULL. 217..

sample of one of these from near Dog Mountain, about G miles west 

of Narrows, gave the following result on chemical .analysis:

Analysis of efflorescence from near Narrows, Or eg. 

[Analyst, George Steiger.]

Insoluble in hot water _._.--.-.-..-..-_.-..._.__..__,_.._.__ 1.25

Sodium oxide, Na2O '...,.. .........'..............,.-.......^. 47.49

Water, H2O (of crystallization) ...... ....................... 10.08

Sulphuric anhydride, S03 ........... .......-_--.....-.--...-- 11.76

Chlorine, Cl................................ ............... 2.90

Carbon dioxide, CO2 (carbonic acid gas)...................... 26.33

Boracic acid, B203 .............. .-.:......................... .28

Total.................................................. 100.09

PROXIMATE COMPOSITION.

Insoluble in hot water .................................... . 1.25

Sodium carbonate, Na2C03 ........----.-..-.-._..-.-....--.. 55.91

Sodium bicarbonate, NaHCO3 ............................... 5.98

Sodium sulphate, Na2SO4 ....-...-...---..-..-,..-.-......... 20.88

Sodium chloride, Nad........................................ 6.17

Sodium biborate, Na2B4O7 (borax)............................... .46 . Water, H2O (of crystallization) .............................. 9.44

Total..-....-..-.-.-.--.-.--..-..-..-.-. ............. 100.09

Judging from the above analysis, the efflorescence from which the 

sample examined was obtained, if in sufficient quantity and commercially accessible, would be of value for the sodium carbonate and 

sodium bicarbonate it contains, but not for its borax.

Every surface incrustation of the nature described above, when of 

sufficient quantity to be of commercial value in case it contains 

sodium bicarbonate, borax, etc., should be carefully sampled and a 

representative portion analyzed. In every playa also auger holes 

should be bored for the purpose of discovering if deposits of valuable 

salts exist below the surface. The clays and silts in a playa should 

also be tested, as they may have absorbed sufficient borax or other 

salts to make them of commercial value.

GEOLOGY.

RECENT VOLCANOES.

. Some account of the recent but now extinct volcanoes of southern 

Idaho was presented in my report on field work done in 1901, a and 

additional data in this connection were obtained during the reconnaissance which furnishes the basis of the present report. In 1902 

the Cinder Buttes, the most instructive group of recently extinct volcanoes thus far discovered in Idaho, were revisited, and three separate 

centers of recent volcanic activity in southern Oregon, not previously

a Bull. U. S. Geol. Survey No. 199.
.RUSSELL.] RECENT VOLCANOES. " 37

known to geologists, also examined. The facts observed in connection .with these four modern and still well-preserved volcanoes or 

groups of volcanoes, when taken in connection with the studies already 

made of many other similar examples in the same region, not only 

contribute to a better understanding of volcanic phenomena in general, but aid in an important way in the interpretation of the records 

of the far more extensive lava flows of greater age in the same region.

The more instructive features of the recent volcanoes of Idaho, 

described in the report referred to above, may be briefly summarized 

as follows: The lava extruded is in all instances a dark basic rock, 

and may all be classed as basalt. In physical characteristics it ranges 

from compact, columnar rock to highly scoriaceous and even pumicelike material. The lava was extruded from the volcanic conduits in 

two ways: part, and by far the larger part, flowed out in a highly 

liquid condition and spread widely over the surface before cooling 

and hardening, and part was blown into the air as angular fragments 

or as clots, bombs, etc., which fell on the adjacent surface and built 

more or less conspicuous elevations. The material extruded in each 

of these ways presents many variations in its physical condition, 

dependent on secondary influences.

Of the lava which flowed out in streams two principal varieties 

may be recognized; one division includes the rocks formed by the' 

cooling of the molten material on land, which, although at times highly 

scoriaceous, especially at the surface of the sheets, is in general a 

dense, compact rock, and on account of the formation of joints as it 

cooled is frequently columnar; the other division contains the lavas 

which entered surface water bodies and became expanded and 

" shredded," or shattered by the resulting steam explosions. The lava 

which was blown into the air presents an interesting series of forms, 

ranging from angular fragments produced by the shattering of the 

material after it had become cool and rigid, through clots, bombs, 

lava cakes, etc., formed of more and more plastic lava, to splashes of 

the magma which were still highly liquid when they fell.

From the two principal variations in the manner in which the volcanoes discharged their lava, two types of elevations about the mouths 

of their conduits resulted. The explosive eruptions led to the building of lapilli and cinder cones, a considerable range in the forms produced resulting from the degree of rigidity or plasticity of the projected fragments and the extent to which they cooled before striking 

the surface. These elevations are usually steep sided and contain 

depressions or craters in their summits, and as a class may be termed 

cinder cones. The lava overflows occurred for the most part quietly, 

without explosions, although in general, as it is believed, following 

explosive eruptions which opened the volcanic conduits for the free 

discharge of the molten rock which rose later and was poured out in 

such volume that the extruded material cooled in a mound above the
38 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BuiL.217.

orifice from which it came and flowed outward in all directions, forming what it is convenient to term lava cones. The cinder cones-are 

high in reference to their diameters, with steep and normally concave 

slopes, while the lava cones are usually low, with gentle and at times 

convex sides and immensely expanded bases.

One of the most notable facts connected with the volcanoes in question is the vastness of the lava fields spread out about them in comparison with the size of the cinder or lava cones found at the summits 

of the conduits from which the material came.

On the surfaces of the lava flows there are two principal features, 

which are dependent<on the ratio between the motion of the lava and 

the degree of rigidity of the crust formed on its surface as cooling 

progressed. When the cooling and stiffening of the surface occurred 

without marked disturbance from the flow of the still liquid material 

beneath, smooth, swelling, convex surfaces resulted, which at times 

were wrinkled and even forced upward into hollow folds. These folds 

show the characteristics of pahoehoe, as such surfaces are termed in 

the Hawaiian Islands. (PL XII, A.) When, however, the underflow 

beneath a brittle crust caused it to become fractured, and the fragments thus produced were tossed about in much the same manner 

that the cakes of ice in an ice jUm are crushed together and piled up, 

'a rugged surface, simulating what is termed aa in the Hawaiian 

Islands, resulted. (PL XII, B.)

The numerous instructive features just referred to, which were 

described and discussed in some detail in the report on the observations made in 1901,« were found in the crater and lava flows of southeastern Oregon examined in 1902, and still other phenomena belonging to the same general category were observed. The reexamination 

of the Cinder Buttes enabled me to verify and extend the results 

previously recorded.

CINDER BUTTES.

The Cinder Buttes are situated on the west side of the Snake River 

Plains, about 70 miles west of Blackfoot, Idaho. They are not conspicuous on account of size, as the highest crater in the group rises 

but 600 feet above the adjacent plain, but are remarkable for the 

vast amount of lava that flowed from them and for the many instructive details they present in reference to the behavior of volcanoes 

which erupt basic and easily fusible lava. ,

The additional facts concerning this most interesting group of craters and lava flows, at least in a measure supplementing the account 

of them already published," relate principally to the floating away of 

large fragments of a ruptured tuff cone on the surface of the outflowing lava stream, a greater variety in the volcanic bombs occurring 

about the crater than was previously known, and the occurrence of

a Bull. U. S. Geol. Survey No. 199.
U. S. GEOLOGICAL SURVEY

CRAGS OF TUFF ON LAVA FLOW, CINDER BUTTES, IDAHO.
RUSSELL.] RECENT VOLCANOES. 39

distinct beds of compact lava in the walls of cinder cones, due to the 

running together and hardening into a single mass of many splashes 

of liquid lava, etc.

Breached cinder cones and crags of tuff floated on lava streams. 

There are several well-defined craters built of lapilli and scoria among 

the Cinder Buttes, which were breached by the lava that escaped from 

them, and in one instance of this nature large masses of the parent 

crater were floated away on the surface of the lava stream which 

escaped through an opening in its wall. The floated masses range in 

general from 20 to 50 feet in diameter and from 40 to 50 feet -or more on 

a side. They occur in a well-defined train, extending down the lava 

stream which escaped from a breach in the parent crater for a distance 

of about 2 miles. The masses are always angular and are bounded 

by rough surfaces that have resulted from fracture. They consist of 

reddish tuff, formed by the partial consolidation of lapilli, or of adhering clots of lava that were plastic when they were brought together. 

In color and composition they correspond with the portion of the cinder and lapilli cone still remaining intact, and differ from all other 

rock in their vicinity. They are in striking contrast with the black, 

generally smooth but in places wrinkled or fractured lava surface on 

which they occur. About the base of nearly every one of the crags 

the surface of the sustaining lava is depressed so as to form a moatlike trough which completely encircles it. Some of the features just 

described, including the depressions encircling the bases of the crags, 

may be recognized in the accompanying photographs. (PL III.)

It is of interest to note that the surface of several of the lava streams 

about the Cinder Buttes, for a distance of a mile or two from. their 

sources, has subsided since it hardened, owing to an outflow of the 

still liquid lava from beneath a rigid crust. The amount of this 

subsidence is in several instances from 50 to 70 feet. As a result of 

such subsidence in the central part of a lava stream its marginal 

portions are sometimes left stranded, and a precipitous broken 

escarpment, facing the subsided area, borders the portion of the 

stream from which the lava outflowed. On the border of a lava 

stream which has been lowered at times large blocks of the stranded 

crust slope downward toward the subsided area.

In the case of the Northwest lava flow, i. e., the one on which the 

crags of tuff, etc., described above, occur, there has been a subsidence 

of the surface of the flow throughout the first mile or more of its 

course, and a lowering of the crust formed on its central part of 50 to 

70 feet. A portion of the flow, a square mile or more in area on the 

west side of the stream, was left stranded by this subsidence at a 

higher level than the surface of the lava, which continued to flow to 

the north.

From the facts briefly described above it seems evident that the 

crags of tuff, etc., on the surface of the Northwest lava streams are
40 GEOLOGY OF SW. IDAHO AND SE. OREGON. [uuLL.217.

fragments of the breached crater from which the lava came, and that 

they were floated on the surface of the plastic lava. The floated fragments are composed of rock which, on account of its porous and usually 

scoriaceous condition, is lighter than the usually compact lava on 

which they occur, but they depressed the viscous surface on which 

they rested in the same manner that a brick might depress the surface of pitch. The floated fragments were not carried to the end of 

the lava flow, for the reason that a crust was formed on the stream 

of molten rock from beneath which the still liquid material escaped. 

Owing to -the outflow beneath, the crust remained stationary and 

with its freight of tuff was gradually lowered to the position it now 

occupies. That the crags to which attention has been directed are 

not islands in the lava stream is clearly shown by comparing them 

with well-characterized occurrences of that nature, one of which is 

shown on PL IV, A. The stranded blocks of lava about an island in a 

lava stream which has subsided are inclined away from it, as may be 

seen in an example of this nature shown in the photograph just 

referred to. In such instances the result is much the same as may be 

observed on the borders of a river which has subsided after a sheet of 

ice had formed on its surface; in instances of this nature, as is well 

known, cakes of ice left stranded on the banks of the stream are 

inclined downward toward its center. About the islands in a lava 

stream which has been lowered by the outflow of the liquid rock from 

beneath a solid crust, the portions of the crust left stranded slope 

away from the central part of the island and nothing resembling the 

moat-like depression observed about the floated crags described above 

is even suggested.

In some instances observed about the Cinder Buttes, the subsidence 

of the central part of a lava appear to have been so gentle that the 

surface sheet of stiffened but still somewhat plastic material was not 

seriously broken, and still remains in the condition of pahoehoe. At 

other times a more rapid lowering of the surface, or the presence 

of a rigid and brittle crust, caused a large amount of fracturing and 

the heaping up of the pieces produced so as to make a characteristic 

aa surface. About the bases of the floated crags on the Northwest 

lava flow, described above, typical examples of each of these classes 

of lava surfaces are to be found. In some instances the crags rise 

from smooth, swelling, and frequently corrugated pahoehoe surfaces, 

and at other places are surrounded by the chaos that is characteristic 

of aa surfaces.

Volcanic bombs. The volcanic bombs strewn about the Cinder 

Buttes are so abundant that in several instances they form a large 

part of the material of which the craters are composed and present 

several well-characterized varieties.

The term "volcanic bomb" is usually employed to designate the 

class of projectiles blown out of volcanoes, which, on account of their
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. IV

.-t. ISLAND OF LAPILLI IN LAVA STREAM, CINDER BUT7ES, IDAHO.

Ji. SCORIA AND BOMB CONES, "THE ICE WELLS," CINDER BUTTES, IDAHO.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. V

VOLCANIC BOMBS, CINDER BUTTES, IDAHO. 

Four-tenths natural size.
RUSSELL.] KECENT VOLCANOES. . 41

revolving about au axis during their flight and while still plastic, 

assumed more or less regular spherical or ellipsoidal shapes. Typical 

examples of such bombs, ranging in form from nearly perfect spheres 

to elongated oval bodies with projections or "ears" at the ends of 

the longer axis, were obtained in abundance. The central body as 

well as the projections in those examples are marked by spiral lines 

and ridges, produced by the rotation of the mass while yet hot and 

viscous or plastic. Illustrations of such forms which preserve unmistakable .evidence of having rotated while yet plastic are presented on 

Pis. V-VI. The bombs which most nearly approached the typical 

shapes just referred to range in size from less than an inch in length 

to masses that are 9 feet long and 12 feet in circumference in the 

center. In addition to the bombs with characteristic spherical or 

ovoid shapes, many other forms, some of them conspicuously irregular, were noted.

In some instances, as illustrated on PI. VI, a mass of plastic lava, 

after being fired into the air and acquiring the common " foot-ball" 

shape, seems to have fallen straight downward, and the projecting 

ends or ears, being still plastic, were bent inward and perhaps flattened on the central portion of the mass. A great variety of bombs 

of this description, with recurved and infolded ears, was observed. 

Examples are also common of masses of lava which were projected 

into the air, and on falling acquired a pear-shaped or tear-drop form. 

These bodies, which seem to have fallen straight downward, as is indicated by their shapes, are of all sizes up to 2 feet or more in diameter. 

In many instances the tapering end is curved, or even folded down 

onto the body of the bomb, so as to produce shapes curiously like 

certain varieties of squash with curved necks .These pear-shaped 

and squash-shaped bombs were in many observed instances evidently 

still plastic when they struck the ground, as is shown not only by the 

fragments of lapilli, etc., adhering to their lower surfaces, and partially embedded in their outer crusts, but by a bulging at the base or 

flattening due to a change of shape on striking.

In addition to the bombs with more or less symmetrical forms, due 

to masses of plastic lava cooling and stiffening while rotating in the 

air or falling from aloft, there are many irregularly shaped bodies 

which originated in a similar manner. These are frequently greatly 

elongated, loosely twisted shreds, perhaps several feet long and only a 

few inches in transverse diameter in the thickest part. One of the 

most bizarre of these irregular forms is represented on PL VIII. This 

ram's horn-like body of dense light-colored lava measures 13 feet in 

length and 8 inches in diameter in the thickest portion. It lies on the 

west side of the highest of the Cinder Buttes, about one-third of the 

way from its base to the top, and was hurled through the air to a distance of about one-half mile. On striking, it was still sufficiently 

plastic to become indented by the stones on which it fell, some of
42 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BULL.217.

which still adhere to its lower surface. On account of its plastic 

consistency it did not break when it fell, but has since been fractured, 

probably on account of changes of temperature.

Many projectiles, either complete or more or less shattered, of the 

same general character as the one shown on PL VIII, occur about the 

Cinder Buttes, and in most if not all instances they are composed of 

dense, compact, light-colored rock, which on freshly fractured surfaces looks not unlike hard-burned stoneware and resembles the 

material forming the immediate borders of basaltic dikes or, the whole 

of very thin dikes of similar character. It is evident that the lava 

forming the irregular shred-like bombs cooled quickly from a liquid 

or highly plastic condition, and that the steam and gasses contained 

in the original magma escaped, for the most part, without leaving 

vesicles..

When the bombs are broken so as to expose their interiors they 

present at least three well-defined variations in structure. Certain 

ones, including the elongate, twisted forms described above, are 

compact throughout or exhibit only irregular and, frequently, much 

extended cavities, such as steam or gases leave in cooling lava, and 

are either light, and in fact almost white, or glossy black in color. 

In sections at right angles to the longer axis something of a spiral 

arrangement of the steam cavities, cracks, etc., is apparent, and on 

their exterior there is more or less evidence of the influence of rotation while the mass was still plastic. The. bombs having these characteristics seem to have been formed of highly plastic or nearly liquid 

lava, from which the contained steam and gases escaped freely.

Bombs of a second variety, characterized by their rudely spherical 

shapes, rough exteriors, and highly vesicular and frequently nearly 

hollow interiors, but without surface crusts, spiral lines or ridges, or 

projecting ears, occur in abundance, especially in the walls of parasitic cones or what may perhaps be termed driblet cones of large size. 

These rough spheres range in diameter from a few inches up to 2 feet 

or more, and the walls of the large cavities within frequently present 

the appearance of "pulled dough," as if marked expansion of the 

steam cavities had occurred while the material was viscous. (PL 

VII.) The bombs of this variety are sometimes flattened and bear on 

their under surfaces impressions of the material on which they fell. 

At times they adhere one to another, and in some instances were sufficiently plastic to flow after coming to rest. The occurrence of these 

bombs in chimney-like piles, about openings in lava streams, and in the 

walls of the so-called ovens to be described later, indicates that they 

were tossed out of openings in the crusts of lava streams, but did not 

make any considerable journey in the air. They form a connection 

between projected clots of vesicular lava, such as are commonly 

termed "cinders," and true bombs, which were thrown to a considerable height and cooled while rotating.
U. S. GEOLOGICAL SURVEY 

VOLCANIC BOMB, CINDER BUTTES

Four-tenths natural size.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. VII

VOLCANIC BOMBS, CINDER BUTTES, IDAHO. 

Three-tenths natural size.
U. S. GFOLOGICAL PURVEY 

VOLCANIC BOMB, CINDER BUTTES, IDA

Length, 13 feet; greatest diameter, 8 inches.
RUSSELL.] ' RECENT VOLCANOES. '43

The third common type of bombs includes those which are cellular 

within the vesicles diminishing gradually in size from center to circumference and inclosed in a thin rind or crust. In some instances 

there is a thin layer of cellular lava on the outside of the hard rind, 

but more frequently the surface is smooth, glossy black, and in many 

examples broken by shrinkage cracks which have been widened by 

the expansion of the material within after a thin surface crust had 

formed. (PL X, A.)

The interior structure of these bombs closely resembles that of 

certain bombs found on Ascension Island and described by Charles 

Darwin. In order to show this resemblance more definitely, a figure 

of a partial section of. one of .the bombs referred to, published by 

Darwin,a is reproduced on PL IX by the side of a similar specimen 

from the Cinder Butte's! In each case there is a conspicuous and 

gradual increase in the size of the vesicles in the central scoriaceous 

mass, from the inner side of the inclosing .rind to the center. The 

explanation of this peculiar internal structure advanced by Darwin 

is as follows: . .

This structure is very simply explained, if we suppose a mass of-viscid, scoriaceous matter to be projected with a rapid, rotatory motion through the air, for 

while the external crust, from cooling, became solidified (in the state we now see 

it), the centrifugal force, by relieving the pressure in the interior parts of the 

bomb, would allow the heated vapors to expand their cells; but these being 

driven by the same force against the already hardened crust would become, the 

nearer they were to this part, smaller and smaller or less expanded until they 

became packed into a solid, concentric shell. As we know that chips from a 

grindstone can be flirted off when made to revolve with sufficient velocity, we 

need not doubt that the centrifugal force would have power to modify the structure of a softened bomb in the manner here supposed. Geologists have remarked 

that the external form of a bomb at once bespeaks the history of its aerial course, 

and we now see that the internal structure can speak with almost eqtial plainness 

of its rotatory movement.

As stated in my report on a reconnaissance in Idaho in 1901, b the 

observations then made concerning the cellular bombs strewn about 

the Cinder Buttes are not in harmony with the explanation quoted 

above. Later studies serve to strengthen this conclusion aiid to lend 

additional support to the hypothesis advanced in the bulletin referred 

to. In brief the explanation of the cellular condition of the bombs in 

question, and the increase in the size of the vesicles they contain 

from beneath the crust to the center, which apparently best satisfies 

the observed facts, is that masses of steam-charged lava, tossed into 

the air from pools of liquid rock in craters, cooled quickly at the surface and formed a dense crust, which prevented further escape of 

steam from within, and as the lava continued to cool, the change 

gradually progressing from the circumference inward, there was an

a Darwin, Charles, Geological observations on volcanic islands visited during the voyage of 

H. M. S. Beagle, London, 1844, p. 36. 

«>Bull. U. S. Geol. Survey No. 199.
44 GEOLOGY OF 8W. IDAHO AND SE. OEEGON. [BULL. 217.

extrusion from the cooling lava of steam or gases previously held in 

solution in the molten rock. The regeneration of steam or gases in 

this manner would tend to expand a bomb, thus leading to a cracking 

of the first formed crust-and a widening of the cracks, as is illustrated 

on PL X, A. The change referred to would also favor the formation 

of larger and larger vesicles within a bomb as the cooling and stiffening of the material composing it progressed. In addition to the 

facts referred to tending to support the hypothesis here restated, it 

may be noted that the bombs seen about the Cinder Buttes which 

show the internal structure, neither in their forms nor in their surface markings exhibit evidences of rapid rotation, and moreover occur 

on the crests and inner slopes of craters or in situations that do no. 

indicate a long aerial flight. The impression that one gains from see 

ing large numbers of these bombs in the position in which they fel"! 

is that they are formed of masses of plastic lava which were tossed 

out of craters with only sufficient rotary motion to give a spherical 

form, but were not fired high in the air and did not acquire the spindle shape with twisted projections at either end, so characteristic of 

bombs that rotate rapidly while cooling.

Bombs of the various external shapes and with the wide range in 

interior structure described above occur in great numbers about the 

Cinder Buttes, and in fact furnish a very considerable portion of the 

fragmental material of which they are composed. Mingled with the 

bombs in the walls of many of the craters, as previously described, a 

are great quantities of thin, nearly flat, cake-like masses of lava, 

which were formed by the cooling and hardening of small bodies or 

splashes of lava that had been projected into the air and were still 

liquid when they fell. These flat cakes furnish illustrations of one 

extreme of the many variations presented by the material thrown out 

by volcanoes during explosive eruptions; a series which includes 

scoria, clots, several varieties of volcanic bombs, and angular fragments, such as lava blocks, lapilli, volcanic dust, etc. This wide 

range in the products of volcanic explosions in reality presents an 

orderly sequence, dependent on the degree of fluidity, plasticity, or 

rigidity of the material at the time it was blown into the air.

If the material forming the summit portion of the column of lava 

within the conduit of a volcano becomes rigid before steam explosions 

beneath cause it to be fractured and the fragments blown into the air, 

angular blocks of lava, lapilli, dust, etc., are produced. If the material is plastic or viscous, clots may be blown out, and cool as scoriaceous masses, or so-called cinders, which have rough, irregular, but 

not fractured surfaces. If such clots are projected high in the air 

and cool while rotating, bombs result. Should the lava be still more 

thoroughly fused at the time it is projected into the air, it may still 

be liquid on striking, and form lava cakes, or even spread over the

a Bull. U. S. Geol. Survey No. 199.
U. S. GEOLOGICAL SURVEY

BULLETIN NO. 217 PL. IX

-f

i

r

SECTIONS OF VESICULAR VOLCANIC BOMBS. 

Fig. 1! is one-third natural size.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. X

A. CRACKED SURFACE OF VOLCANIC BOMB, CINDER BUTTES, IDAHO. 

Four-tenths natural size.

. FRAGMENT FROM A CINDER CONE, SHOWING DENSE PORTION DUE TO HARDENING OF SPLASHES OF LIQUID LAVA, CINDER BUTTES, IDAHO.

Four-tenths natural size.
RUSSELL.] BEOENT VOLOANOEO. 45

surface and, additional material of the same character being supplied, 

form tile-like sheets. This entire sequence is admirably illustrated 

by the projectiles which accumulated to form the Cinder Buttes.

The occasional presence of balls of dense lava on the surfaces of lava 

flows, described by J. D. Dana in the case of certain lava streams in 

the Hawaiian Islands, and observed by me in Idaho,® as well as the 

presence of analagous spherical masses of lava in the crater walls of 

certain of the Cinder Buttes, suggest, as a tentative hypothesis, that 

during the boiling of lava in a crater, masses of fused rock may become 

cooled, and, owing to rotation produced by the movement of the molten 

or plastic material about them, acquire a spherical form before being 

blown out or carried away by outflowing lava. The compact, roughsurfaced, spherical balls sometimes found about volcanoes appear to 

have originated in some such manner, and not from the rotation of 

plastic material projected into the air.

The sequence of events in the history of the Cinder Buttes, as 

recorded by the,accumulations of projectiles still remaining and by 

the extensive lava flows which were discharged from the same volcanic 

vents, is briefly as follows: The eruptions in a large number of 

instances began, so far as can be judged from the evidence now available, with explosions which caused considerable quantities of cool - 

and rigid lava in the form of lapilli, dust, etc., to be projected into the 

air. Later came similar violent discharges of plastic lava which formed 

scoria and volcanic bombs, and later still, liquid lava was ejected. 

This fell before cooling, and spreading over the surface where it 

struck formed lava cakes. Following these explosive discharges, 

or accompanying the later ones, great volumes of highly liquid lava 

were poured out. This lava was extruded quietly and flowed over the 

surface of the surrounding plain so as to form sheets many square 

miles in area. The close of the eruptions, in several instances at 

least, was not characterized by a return of the conditions which produce explosions, but the outflow of liquid lava decreased gradually 

and finally ceased, the craters being left with nearly level floors of 

highly vesicular rock having the surface characteristic of pahoehoe.

Lapilli cones, cinder cones, etc. The term cinder cone is commonly 

used to designate the piles of projectiles which have accumulated 

about volcanic vents, irrespective of their precise character. While 

the cones and'craters referred to are in general composed of irregular scoriaceous masses of lava, usually referred to as "cinders,"it 

will be seen from the brief description given above of the wide range 

in the nature of the projectiles of which they are composed that several varieties of '' cinder cones " should be recognized.

When angular fragments of hard lava, such as blocks of rock, lapilli, 

dust, etc., are blown out of volcanic vents, they usually fall about 

the opening from which they come and accumulate in a conical pile

« Bull. U. S. Geol. Survey No. 199, p. 114.
46 GEOLOGY OF SW. IDAHO AND SB. OEEGON. [BULL.217.

with a depression or crater at the summit. The outer slopes of these 

cones frequently form angles of 30° to 35° with a horizontal plain, 

the angle being essentially the angle of repose of the fragments 

of which they are built, but their profiles are concave instead of 

straight lines. The reason for the downward curves presented by 

the sides of such cones is not definitely understood, but seems 

to depend on the fact that the structures are built of fragments 

of different sizes and shapes. Vertical sections through such piles 

commonly show, as is well known, two series of beds, one series 

dipping away from the crater in the summit, and forming the outer 

slopes of the cones, and the other series dipping from the rim of the 

crater toward its bottom. The junction between these two series of 

opposite-dipping beds in the rim of a crater is not a sharp angle, as 

sometimes represented, but a curve, convex upward. The cones 

referred to are symmetrical when built of fragments projected vertically, unless the influence of the wind in carrying the material in one 

direction more than another made itself felt. Cones or craters built 

of angular fragments with surfaces produced by fractures are sufficiently distinct from the similar structures built of other kinds 

of projectiles to be specially designated, and may with propriety be 

termed lapilli craters, or lapilli cones in case a depression in the summit of the pilejs absent.

When the material projected into the air from a volcanic vent is 

plastic, and falls in irregular clots and rough scoriaceous masses, it 

frequently forms steep-sided piles with chimney-like openings within. 

Owing to the frequently large size of the masses which fall, their 

rough surfaces, and also to the fact that they are in many instances 

still plastic when they come to rest, the slopes of the structures produced, both on the outside and within, are commonly steep, and in 

some instances are nearly vertical, but the outer slopes of these hollow 

piles are normally less steep than the walls of the openings within. 

Piles of congealed clots of this nature present several instructive 

variations. At times they are steep-sided chimney-like forms, such 

as are illustrated on PI. III. In other instances their encircling walls 

are contracted at the top so as to leave only small openings, and in 

extreme examples of this nature a complete roof is formed by the 

adhering of the clots blown out, and a beehive or oven-like structure 

results, such as is shown on PI. XI. The chimney-like elevations produced in the manner just referred to have been designated driblet 

cones by J. D. Dana, but for the entire series of cones, craters, etc., 

built of scoriaceous or cinder-like clots of lava the term cinder crater 

or cinder cone seems appropriate.

For the sake of avoiding a lengthy discussion of the classification 

of elevations produced by the accumulation of volcanic projectiles 

about the vents from which they were blown out, I may briefly state 

that in certain instances well-characterized volcanic bombs form the 

greater portion of an elevation with a crater in its top, and in some
RUSSELL.] RECENT VOLCANOES. 47

instances similar elevations are composed principally of lava cakes 

formed, as already explained, by the cooling of splashes of liquid lava 

after coming to rest. Examples of cones or craters formed exclusively or in large part by the two methods just cited, however, are so 

rare that special names for them do not seem to be necessary.

It frequently happens that a volcanic hill or mountain is composed 

of projectiles of all the classes considered above, as, for example, when 

large angular blocks of lava are ejected, together with lapilli and dust, 

and at some time in the life of the volcano plastic or liquid lava is blown 

into the air and forms scoria, bombs; lava cakes, etc. Such composite 

cones or craters built of the products of explosive eruptions are illustrated by several characteristic examples among the Cinder Buttes.

There is one feature of lapilli and scoria cones which does not seem 

heretofore to have attracted attention. Interbedded with the fraginental material in the walls of such craters there are sometimes irregular sheets of compact and usually reddish lava, ranging in thickness 

' from a few inches or less to many feet, and presenting all variations 

in extent from, a few square inches to several hundred square yards, 

and resembling true lava flows. These compact layers occur both in 

the outer and inner slopes of a crater, and at times a single bed in 

one part belongs with the steeply sloping layers of the inner cone, and 

changing its dip in the part beneath the crater's rim, passes into the 

outward-dipping series of beds. As may be seen at the Cinder Buttes, 

such beds of compact lava sometimes contain scoriaceous masses, and 

on their edges become thin and terminate irregularly in accumulations of lapilli or scoria. Some of these features may be recognized 

in the small sample from the wall of a cinder cone, shown in PI. X, B.

The range in size of the compact beds just described, the presence 

in them, of scoriaceous masses, and the manner in which they terminate, etc., show that they are due to an accumulation of liquid or 

highly plastic splashes and clots of lava, which united one with 

another as they fell. In harmony with this explanation is the fact 

that in many instances a sheet of lava of the nature under consideration is completely inclosed in lapilli or scoria. In sections of lapilli 

and scoria cones to be seen among the Cinder Buttes numerous 

examples of interbedded sheets of compact lava may be seen which 

are due to the running together of liquid or highly plastic splashes 

and clots in the manner just explained, and similar occurrences were 

seen elsewhere, particularly at the Jordan Craters described below.

The notes presented above are intended as a supplement to the 

more general account of the Cinder Buttes contained in Bulletin No. 

199 of the United States Geological Survey, and I trust will be followed by a detailed survey of that unique region. In the publication 

just referred to, several isolated craters and groups of craters situated in southern Idaho are described, and the list of these recent volcanoes is here extended by an account of three similar centers of 

eruption in southeastern Oregon.
48 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BULL. 217.

JORDAN CRATERS.

In the east-central part of Malheur County, Oreg., and from 18 to 20 

miles west of the Idaho-Oregon boundary, there are four recently 

extinct volcanoes, which are here termed, collectively, the Jordan 

Craters. They are situated to the north of Jordan Creek, and to the 

west of its tributary known as Cow Creek. The four craters referred 

to are nearly on a line bearing a little west of north and are approximately 3 to 5 miles apart, although the distance of the one at the 

north from its next neighbor is somewhat greater than the spaces 

between the others in the series. While but four recent craters are 

here referred to, there are certain rounded hills to the west of the 

south end of the series which .are probably of volcanic origin, and 

perhaps represent ancient craters, but these have not yet been 

examined.

Three of the four craters referred to that is, all but the most 

northerly in the series are situated in a valley, and the lava which 

flowed from them spread in all directions and built up lava cones with 

broad bases and low surface slopes. Each crater rises about 500 feet 

above the plain, but by far the greater part of this elevation is gained 

in the broad, low lava slopes surrounding the small buttes which mark 

the centers of eruption. The central elevations are in general about 

150 feet high, and are composed of lava which occurs mostly in thin 

sheets. There is an absence of scoria in detached clots and of lapilli 

or other ejected material, such as is blown into the air during explosive 

eruptions. In. short, they are elevations formed by the cooling and 

hardening of lava which overflowed from the summits of volcanic conduits in all directions, so as to form low cones with immensely 

expanded bases. When seen in profile, especially at sunrise or sunset, they are at once recognized as typical examples of what I have 

ventured to term lava cones in distinction from elevations built by 

the accumulation of projectiles.

The central and summit portion of each of the Jordan Craters is 

usually circular, with steep outer slopes, and in one instance contains 

a crater-like depression. This cavity in the summit of the cone, as 

in 'the case of many similar lava cones in Idaho and Oregon, is due to 

the falling in of a dome-like structure composed of thin lava sheets, 

the subsidence being caused by the escape of still liquid lava laterally 

from beneath a rigid crust.

It is convenient to designate the Jordan Craters by numbers, beginning at the south end of the series and proceeding northward. A 

brief examination serves to show that No. 1 is the oldest in the series; 

next in age is No. 3, then No. 2, and last and youngest of all, No. 4. 

Their relative ages are shown by the degree to which their surfaces 

are weathered and the extent to which they are covered with soil and 

vegetation. The slopes of the oldest crater are smooth, with but few
RUSSELL.] BECENT VOLCANOES. 49

rocky crags visible, and are covered with soil mostly of eolian origin, 

in which a strong growth of sagebrush, etc., is conspicuous. Crater 

No. 3 is less completely concealed beneath accumulations of atmospheric dust than No. 1, and is less densely overgrown with sagebrush, 

while No. 2 presents a rough surface of hard black lava, on which 

pressure ridges are conspicuous, although notable quantities of atmospheric dust have accumulated in the depressions, and bushes and 

bunch grass grow in cracks and crevices on seemingly bare cindery 

crags and ridges.

While Craters Nos. 1, 2, and 3 are instructive on account of the 

many square miles of lava poured out from them and the various 

stages reached in its change to smooth pasture land, the chief interest 

of the general locality centers about Crater No. 4, at the north end, 

the youngest of the series.

Crater No. 4- This very modern crater, unlike its companions, 

came into existence on a somewhat steep-sloping hillside, which was 

trenched by erosion channels previous to the volcanic outburst, and 

the great flood of extruded lava flowed away in one principal direction. Owing to the freedom afforded for the escape of the lava down 

the slope below the orifice from which it came, a large portion of the 

cinder and ]apilli crater, built during an early stage in the history of 

the volcano, has been spared,'and furnishes important evidence as to 

the general sequence of events, which, as it now appears, normally 

accompany the building of lava cones.

Crater No. 4, as it exists to-day, is inr p^rt a cinder and lapilli cone, 

and in part a lava cone, and extending over an area of about 50 square 

miles on its southeastern side is a black lava field entirely bare 

of vegetation (PL XII, A). Although differing conspicuously in its 

details from the associated craters in the same series, the one here considered was evidently built in the same manner as its companions, 

but owing to its being located on a sloping surface, the products of 

the earlier stages of the eruption which built it were not buried by 

the great effusion of highly liquid lava poured out later, as was the 

case in numerous observed instances, where, similar eruptions have 

occurred on a plain.

Throughout about one-half of the periphery of the cinder and lapilli 

cone forming Crater No. 4, the older rocks, consisting mainly of Tertiary rhyolite, are without a covering other than a thin layer of soil, to 

within a distance of 800 or 1,000 feet of its base. This fact suggests 

that some evidence may perhaps be obtainable as to the nature of the 

break or opening through which the eruption that built the crater 

reached the surface. The testimony in this connection, however, is 

meager. On the hillside, where the crater is situated, and extending 

in an essentially straight line from it, both to the north and south, 

there is a faint escarpment averaging perhaps ] 5 feet in height, and 

facing east. This escarpment has the general appearance of a fault

Bull. 217 03 4 ' ~ .
50 GEOLOGY OF SW. IDAHO AND SE. OEEGOIST. [BULL.217.

scarp, but is by no means certainly of that nature. The only unquest 

tionable evidence of a break in the rocks on which the crater stands 

is furnished by a row of about 12 driblet cones, situated in a line 

extending west from the principal center of eruption and up the slope 

of the hill at right angles to the faint escarpment referred to above. 

The portion of the break on which the driblet cones are located; 

situated at a distance of about 1,000 feet from the center of the main 

crater, shows no evidence of a differential movement of its walls. 

There is then but slight evidence of a shattering or faulting of the 

country rock preceding or following the birth of the volcano.

The portion of the original pile of cinder and lapilli remaining at 

Crater No. 4 is highest on the south side of the crater, where it rises 

about 100 feet above its outer base and somewhat more above £he irregular pit it partially inclosed. The cone has lost much of its symmetry, 

owing to the falling of its inner surface, and on the south side of the 

crater presents a fairly good section of outward-dipping layers of lapilli 

and of compact reddish lava. The compact layers referred to are 

among the more interesting features of the section, and while having 

the appearance of lava flows which descended the outer slope of the 

lapilli and scoria cones when it was but partially completed, are in 

reality due to the flowing together and cooling in one mass of many 

splashes of liquid lava. This mode of origin of the dense compact layer 

is shown by it containing angular fragments of lapilli and by small, 

isolated, lenticular masses of the same nature completely embedded 

in lapilli, with which it forms a complete gradation. More than this, 

the surrounding surface of rhyolite, adjacent to the base of the cinder 

and lapilli cone, where not concealed beneath lava flows, and to a 

distance of about 800 feet, is thickly strewn with reddish clots of lava, 

which were liquid when they fell and in general ran together, so as to 

form a tide-like sheathing to the surface. This material spattered 

out of the crater and falling well beyond, its base is of the same character as the layer of dense lava built into its wall and covered by 

subsequent showers of lapilli. The preservation of the rough, angular pavement, composed of congealed splashes of lava about the crater, 

which fell in a liquid condition, thus serves to explain the history of at 

least certain compact layers in the walls of the cinder cone, the most 

noticeable of which has a thickness of between 10 arid 20 feet. Similar compact, usually reddish, layers of lava in cinder cones have been 

observed at the Cinder Buttes and elsewhere, as already explained, 

and are evidently a common feature of the walls of cinder and lapilli 

craters built by volcanoes which discharged highly liquid lava.

After a small cinder and lapilli crater had been built by the volcano 

under discussion, it is evident from the records still remaining that 

liquid lava rose within it and breached its wall, both on its west and 

southeast borders. The lava which escaped westward was small in 

amount and now forms a pool-like sheet of black pahoehoe about 600 feet
BTJSSELL.-] . RECENT VOLCANOES. 51

across. Some of the lava in this pool, however, came from the crack 

mentioned above, along which there is situated a row of driblet cones. 

After the opening of a breach in the west side of the crater the opening was partially closed by a discharge of lapilli, but not rebuilt to 

its former height. On the southeast side of the crater the portion of 

its wall which has disappeared includes about one-third of its original 

extent, and through the break there was outpoured a flood of lava 

which inundated an area of about 50 square miles. The lava cooled 

in the breach it had formed in thin sheets, so as to produce a steepsided ridge, which completely occupies the break and unites with the 

remaining fragments of the lapilli and cinder cone at each end. This 

ridge of lava is of the same nature as the walls of typical lava cones, 

being formed of thin sheets of highly vesicular rock, each one seemingly formed by the congealing of a thin overflow from the crater and 

succeeded by another similar overflow, until a steep ridge composed 

of overlapping lava sheets was produced. The main discharge of lava 

took place beneath the crust thus formed, after the manner so common 

in highly liquid lava streams, and escaped through tunnels.

The final' drawing off of the molten material, which once filled 

Crater No. 4 up to the level of the top of the rim of congealed lava on 

its eastern side, allowed the crust of scoriaceous and ropy pahoehoe 

lava formed within it to subside, and although in part broken it still 

rests at the bottom of the irregular pit it left about 100 feet lower 

than its former position. Since the subsidence of the floor of the 

crater there has been some tumbling in of its unsupported walls, but 

the cakes of corrugated lava on its floor are still to a large extent 

unconcealed.

The rise of liquid lava within a cinder and lapilli cone, as in the 

example just described, the building of a raised rim in the breach in 

the crater walls composed of fragmental material, and the subsequent 

lowering of the. lava crust formed on the pool within the crater are all 

features which are found in numerous volcanoes in Idaho and Oregon 

which built lava cones. The greater number of the lava cones that have 

been examined, however, are situated on generally plain surfaces, 

and the floods of outwelling highly liquid rocks, which were extruded 

from them, spread in all directions, and the cinder and lapilli cones, 

which probably in all the instances referred to were formed at an 

early stage in the eruptions, were completely destroyed or buried. In 

the instance here considered, however, owing to the inclination of the 

surface on Avhich the volcano originated, the lava extruded flowed 

almost entirely in one direction, leaving a large portion of the preceding cinder and lapilli cone intact. No. 4 of the Jordan Craters is 

thus in part a cinder and lapilli cone and in part a lava cone. Had 

the slope down which the lava flowed been steeper it is probable that 

the liquid rock would have flowed away too quickly for a lava ridge 

to have been formed about the pool in the summit of the conduit from
52 GEOLOGY OF SW. IDAHO AND 8E. OEEGOW. [BULL.-217.

which it came, a condition illustrated by the Martin lava stream and 

other similar outwellings of lava in mountainous regions,described in 

Bulletin No. 199.

Driblet cones and '' ovens.'1 '' The extrusion of liquid or highly plastic 

lava from cracks or other openings in the crusts formed on lava, as in 

the craters of certain of the Hawaiian volcanoes, has been described 

by J. D. Dana, a and the hollow cones, towers, etc., produced by drops 

or clots of ejected material which adhered one to another, have been 

designated driblet cones. Interesting examples of structures of this 

general nature occur along the fissure mentioned above, which extends 

westward from the most northern of the Jordan Craters.

Situated on the fissure referred to are 10 or 12 oven-shaped piles of 

lava clots, some of which are more or less confluent, so that a definite 

count is impracticable. These piles are nearly circular j with rounded 

summits, and range in height from 15 to probably 25 feet, and are hollow 

within. Some of the examples are still unbroken, and are either completely roofed over or have rudely circular openings at the top, while 

others are broken and prevent free examination of their interiors. 

One characteristic example, shown in PL XI, A, is about 20 feet high 

on the exterior, between 40 and 50 feet in diameter at the base, and 

within contains a symmetrical level-floored chamber, with domeshaped roof, measuring 14 feet in diameter at the bottom and 17 feet 

in height. The walls of this " oven" are about 12 feet thick at the 

base, and diminish gradually toward the roof, which is from 4 to 6 

inches thick. This beehive-like pile, and others similar to it, are 

plainly of the nature of driblet cones, but on account of their shapes 

may perhaps be termed driblet ovens. Their formation, as has been 

explained by Dana in reference to similar structures observed in the 

Hawaiian Islands, is due to the blowing out of plastic lava from an 

orifice and the piling up of the adhering clots about the place from 

which they came. The hollow chimney-like forms thus produced 

were gradually contracted at the top until, in some instances, they 

became completely roofed over. On the interior of these structures 

the lava hangs in pendant stalactite-like masses, usually of a deepreddish color, and from a few inches to 2 feet or more long.

Examples of similar driblets cones of smaller size occur on a lava 

flow that came from the Diamond Craters, to be described later, two of 

which are shown on PI. XI, B. Driblet cones are also present at the 

Cinder Buttes, but in.this case are chimney-like piles, termed on a 

previous page parasitic cones. One example at the Cinder Buttes, 

however, now partially destroyed, has the oven-like shape so 

characteristic of the example present at the Jordan Craters.

Lava '' gutters. " About the bases of the driblet ovens associated 

with Crater No. 4 of the Jordan series, and also at the east base of 

the crater itself, there are localities where lava flowed in narrow

a Characteristics of Volcanoes, New York, 1890,
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. XI

A. DRitsLEI CONE OR OVEN, JORDAN CRATERS, OREGON.

;. DRIBLET CONE, DIAMOND CRATERS, OREGON,
RUSSELL.] RECENT VOLCANOES. ' 53

streams down moderately steep slopes and made for itself well-defined 

channels. These channels are, in general, about 3 feet wide, 3 to 4 

feet deep, with the crests of their bordering ridges elevated about 3 

feet above the adjacent surface, and from 50 to 150 feet long. One 

example of these troughs or gutters, situated at the south base of the 

driblet cone shown on PL XI, A, is about 50 feet long, 14 to 16 

inches wide, and ,3£t'o 4£ feet deep; the crests of the bordering ridges 

are, in general, 3 feet above the adjacent surface. Near its distal 

extremity the trough is completely roofed over, as may be seen in the 

illustration just referred to. The largest example observed is situated on the east side of Crater No. 4, and is about 150 feet long, 3 feet 

wide, with well-defined walls, which rise approximately 3 feet above 

the neighboring surface. These and other similar gutters usually 

begin abruptly at their upper ends and retain a nearly uniform width 

and depth to near thei-r distal extremities, where their walls become 

lower and the troughs merge with broadly expanded, low, dome-shaped 

elevations on a general pahoehoe surface. In some instances the 

liquid lava, as it flowed through one of these gutters, became cooled 

at the surface so as to form a crust, which was left as a slightly 

arched roof above a tunnel as the still-liquid lava beneath flowed out. 

These gutters with roof are in fact tubes or tunnels. In the instance 

shown in PL XIV, a well-defined gutter was formed, in which the 

lava flow decreased until the surface of the current was about 3 feet 

below the crest lines of the inclosing ridges; a crust was then formed, 

and the lava below it flowed out, leaving a roof spanning the gutter 

throughout its length.

The mode of formation of lava gutters seems to be that a narrow 

stream of liquid lava cools at its margins and forms a slight ridge, 

more lava spreading laterally over this ridge, in turn cools and stiffens, 

and then adds to its height, and so the process continues until a welldefined gutter with raised borders is formed. These parallel ridges 

on the borders of a narrow, high-grade lava torrent are in a measure 

analogous to the natural levees built by alluvial-depositing streams.

Lava flow. The lava from Crater No. 4 of the Jordan series, as 

already stated, flows southeastward over a previously stream-eroded 

surface. The lava, just after leaving the crater from which it came, 

formed a stream 545 yards wide, and increasing rapidly in width 

reached a distance of about 8 or 10 miles. The entire flow is by estimate between 50 and 60 square miles in area. The average depth 

may perhaps be taken as approximately 100 feet. These statements, 

it must be remembered, are rough estimates, as no surveys have been 

made, and no maps of the region are available. The lava as it advanced was guided in a conspicuous way by the preexisting topographj*, and in several instances progressed short distances up lateral 

valleys tributary to the main depression down which it flowed. One of 

these small offshoots went nearly due north for one-half mile up a small
54 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BULL.217.

stream valley until its progress was checked by the rising gradient. 

-In places the fresh, black lava is bordered by rims of older rock, 

showing that small canyons in the preexisting surface had been nearly 

filled. Near the eastern limit reached by the lava it ascended the 

small canyon of Cow Creek for about 1 mile, and on cooling formed 

a dam, which now retains the largest and most northern of the Cow 

Creek lakes, as has been described on a previous page. About its 

southeastern margin there are several other lakes.

This great lava stream or lava sheet came from a small crater, 

termed above Crater No. 4, the bottom of which is approximately 300 

feet across. Seemingly the actual conduit must be of still smaller 

diameter. This effusion of highly liquid lava, with only mild explosions at the beginning of the discharge, is a typical illustration of the 

manner in which many extensive lava sheets of Idaho, Oregon, and 

Washington were poured out. The lava from Crater No. 4 seems to 

have progressed mainly by flowing beneath a stiffened crust, and in 

this manner was prevented from cooling quickly, thus permitting it to 

advance far and spread widely. Tunnels in the lava were produced 

by the outflow beneath the crust, formed on its surface, and in certain 

places, as near the source of the stream, the roofs of such tunnels 

have fallen in, leaving irregular pits with overhanging walls from 50 

to 70 feet deep.

In many portions of the lava flow pressure ridges and domes like 

those so common in the immense lava sheets about the Cinder Buttes, 

in the older sheets of Snake River lava, and at other places, are well 

displayed. A photograph of one of these domes, .situated near the 

northern border of the lava sheet, and midway between its source and 

the most northerly of the Cow Creek lakes, is reproduced on PI. XV, A. 

A similar ridge on a lava sheet of somewhat older date, which came 

from the Diamond Craters, is shown on PI. XV, B. That the lava in 

each of these instances was horizontal before being pressed up into domelike ridges, is shown by the corrugation on the surface of the dome, 

to be seen in PI. XV, A, and of the columnar structure in PL XV, B.

DIAMOND CRATERS.

A group of recently extinct volcanoes which it is convenient to term 

the "Diamond Craters" is situated in the east-central part of Harney 

County, Oreg., about 6 miles west of Diamond post-office. The craters, 

about 20 in number, occupy an area of about 5 square miles, and are 

surrounded by at least 30 square miles of rough lava which flowed 

from them.

The Diamond Craters are situated near the base of the long west 

slope of Stein Mountain, and came into existence after the land over 

which they discharged their lava had been deepty dissected by erosion. The lava entered the valleys and canyons and obstructed the 

drainage so as to cause swamps to form. A significant fact in this
RUSSELL.] .' -RECENT VOLCANOES. - 55

connection is that the basins above some of the lava dams are still 

unfilled and have never been occupied by water bodies except ephemeral or plaj7 a lakes. This evidence seems to show that the climate of 

the region has been as arid as at present ever since the lava streams 

obstructed the drainage.

The Diamond Craters are of two types, namely, lapilli cones and 

lava cones, the lapilli cones situated in the southwest and the lava 

cones in the northeast portion of the group. The lapilli craters are 

mostly low, and range in size from one measuring about 2,500 feet 

across to small conical piles of brownish debris. Within the largest 

crater there are hills and mounds of lapilli of the same character as the 

material forming its encircling rim, but rising to a height of from 50 

to 75 feet above it. This great accumulation of fragmental material 

presents an uneven surface consisting of hillocks and crater-like hollows and bears evidence of the occurrence of weak explosions in a 

crater so abundantly charged with debris that it could not clear itself. 

From analogy with streams, the volcano may be said to have been 

overloaded with debris. The fragmental material was blown up into 

hills, and crater-like pits opened in it, but the escaping lava did not 

have sufficient force to eject it from the crater.

The hills and rings of lapilli among the Diamond Craters present 

many variations. Some are simple conical piles of the normal type, 

with depressions in their summits; in others lava rose and, breaching 

the inclosing wall, overflowed. In one instance the lava, after rising 

in a crater and outflowing, was drawn off beneath the crust formed 

on its surface and within the bowl of lapilli, about 600 feet across, 

causing the crust to fall in and leaving a black, irregular gulf 30 

feet deep, and one lapilli ring or crater has another, composed of the 

same kind of material, within it, thus recording two stages of activity. 

In one instance a small crater is composed of compact, spherical lava 

balls or bombs, ranging in size from about 2 inches to the size of small 

shot. These bombs are rough, of a dull-red color, not cellular, and 

exhibit no evidence of rotation excepting their well-rounded shapes. 

Bordering the lapilli craters on all sides are the broad, rough surfaces 

of recent lava fields, which in most instances are covered to some 

extent with sagebrush and other vegetation.

To the north, of the lapilli craters and merging with them as topographic forms are rounded hills composed of lava sheets, which furnish examples of lava cones. The highest of these hills rises about 

400 feet above the adjacent plains and is the highest and most conspicuous summit in the group of which it is a member. This central 

dome is about 1£ miles in diameter, and so far as is indicated by the 

exposures is composed throughout of lava sheets, which occupy its 

summit and descend its sides in all directions to the surrounding 

plain. There is no true crater to be seen, but at the summit of the 

hill there is a gulf, due to the falling in of a large block of lava of
56 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BULL.217.

which the surface of the hill is composed. This gulf has a nearly 

vertical wall from 40 to 70 feet high, runs about east and west, is from 

500 to 800 feet across, and fully 2,000 feet long. Within it are several 

irregular ridges formed by the edges of large tilted blocks of the fallen 

crust. The lava exposed in the walls of the break is irregularly 

columnar, and the topmost layer, which arches over the summit of 

the hill, is about 40 feet thick. This sheet is continuous from one 

side of the hill to the other, passing over the summit, but in the central part of the dome thus formed the rock is highly scoriaceous and 

the bedding less distinct than at the sides. From the gulf in the summit of the hill branching fractures extend down its sides to the east 

and southeast, and in part these radiating breaks are gulfs produced 

by the subsidence and tilting of large blocks of the surface layer. To 

the north of the hill just described there are other elevations of a 

similar nature, but lower and less broken, and about the group there 

are rough lava flows, which came from it and spread over the previously eroded land. On one of these lava sheets there are small 

driblet cones, two of which are represented on PL XI, B.

The interpretation of the facts in reference to the domes of lava 

briefly described above seems to be that from certain of the Diamond 

Craters, which were probably lapilli cones like those of that nature 

still remaining, great quantities of lava were extruded in a liquid or 

plastic condition, which buried or carried away the preceding craters 

of lapilli and, thickening about the opening from which it came, built 

up rounded hills. The outwelling lava flowed down the sides of the 

hill and a thick crust was formed on its surface. After this, the outflow continued beneath the stiffened surface, and finally, when no 

more lava rose from the conduit beneath, a considerable portion of 

the surface crust fell in, leaving the black gulf now forming such a 

conspicuous feature of the summit and eastern side of the largest 

dome. The smaller lava cones or domes to the north of the principal 

cone were less fractured than the main one of the series, and retain 

nearly all of their constructional features unmodified by either fracture, subsidence, or erosion. In fact but slight changes by erosion are 

anywhere visible throughout the entire group of craters.

The rounded hills of lava among the Diamond Craters are, as may 

be judged from the description just given, examples of lava cones, 

and are similar to many other elevations in Idaho and Oregon, which 

were produced in each case by the escape of lava in large volume 

from a volcanic conduit. The chief differences between the lava 

cones here considered and those of the normal type are the prominence of the rounded central hills and the comparatively small extent 

of the surrounding lava fields with which they merge. The usually 

characteristic profile presented by lava cones, consisting of long, gentle slopes leading up to a low central flat-topped butte, is not present. 

In this connection "it may be suggested that the lava poured out to
RUSSELL.] KEOENT VOLCANOES. 57

form the hills referred to was less liquid and did not flow away so 

readily, as in many other similar instances, but thickened in a more 

conspicuous manner than normally about the openings from which it 

came.

In the formation or lava cones, as is the case with the flow of lava 

streams generally, an important condition, and the one which makes 

it possible for a small hill to form with a sheet of lava extending completely over its summit, is the subsurface flow of liquid or plastic lava 

beneath a stiff crust. The degree to-which lava escapes in this manner from a deep accumulation determines the extent to which its surface will be fractured and the amount of surface change which will 

result from tne subsidence of fragments of the crust.

BOWDEN CKATER,

Situated in the south-central part of Malheur County, Oregon, and 

'about 6 miles northeast of the former post-office of Bowden, there is 

an isolated volcanic crater surrounded by an extensive lava flow, 

which it is convenient to designate the Bowden Crater.

The region about Bowden Crater is composed largely of Tertiary 

lacustral deposits, and was deeply eroded before the eruption which 

built the crater. The region, in fact, had all of its present erosion 

features at the time referred to, and has been but slightly modified 

since the volcano ceased to be active..

Bowden Crater and the lava flow about it are composed of basalt. 

There is, so far as observed, a complete absence of the products of 

explosive eruptions, such as lapilli, volcanic bombs, etc. The crater 

rises 600 feet by aneroid measure above the plain at the margin 

of its lava flow, but the lava flow and crater merge with each other, 

and the rise from the outer margin of the lava to the base of 

the cone in the center of the broad, black, desolate tract of fresh rock 

is exceedingly gradual. The upward slope for the first 3 or 4 miles 

is less than 1°; then for about 2 miles it gradually increases to perhaps 2° or 3°, and on the sides of the central and circular elevation 

becomes about 10°. The height of the central elevation above the 

surrounding lava is approximately 200 feet. The walls of the crater 

are of lava of the same general character as that forming the extensive sheet about it, but is perhaps somewhat more scoriaceous. The 

raised rim of the central elevation inclosed a steep-sided circular 

basin, 600 feet in diameter and about 40 feet deep. The bottom of 

the depression is level floored and consists of fine light-colored silt, 

most probably of eolian deposition. During the wet season this 

depression is converted into a shallow lake, which evaporates to dryness in summer.

When standing on the summit of Bowden Crater no other similar 

elevation is in sight, and no other volcanic vent has as yet been discovered nearer than the Jordan Craters, situated about 30 miles to
58 GEOLOGY OF SW. IDAHO AND SE. OREGON. - [BULL.217.

the northeast. It is thus evident that the surrounding lava flow came 

entirely from this single and relatively small center of eruption. The 

lava flow referred to surrounds the crater on all sides, but extends 

farthest to the northwest, or in the direction of drainage of the region 

before the lava was spread out. The area of the lava field is by estimate fully 100 square miles. The thickness, on the supposition that 

it was spread out on a nearly level .plain which was apparently the 

case varies from but a few feet at the margin to about 400 feet at 

the center. The surface of the lava is rough, and many pressure 

ridges are present, particularly within a radius of 2 to 3 miles of the 

crater. Considerable weathering has occurred, and in general the 

entire lava flow, as well as the sides and bottom of the crater, is overgrown with sagebrush, bunch grass, and other -vegetation. On its 

southern border the lava field dammed Rattlesnake Creek, and caused 

a lake of considerable size to form. The bed of this lake has been filled 

to a depth of at least 40 feet with fine alluvium, and, owing in part 

also to the lowering of its outlet by erosion, is now dry and occupied 

by natural meadows of rj-e grass.

Bowden Crater, as may be judged from the facts just mentioned, is 

a typical and most instructive example of a lava cone of the variety 

having a crater at the top. This crater is circular, and not an irregular gulf, produced by the breaking and partial subsidence of a dome 

of lava, as in the case of the highest of the Diamond Craters. The 

precise manner in which the crater's rim was built up is not clear, but 

apparently it was formed by the radial overflow of lava in thin sheets. 

The central part is perhaps due to a drawing off of the molten rock 

which once occupied it, through tunnels in the surrounding lava. 

It is possible, in this and other similar instances, that a circular cinder riin was formed about the summit of the conduit from which the 

lava rose by the cooling and running together of splashes of liquid 

lava. Craters formed in this manner would furnish a* connection 

between those composed of lapilli and scoria and true lava domes, 

like the highest of the Diamond Craters.

SUMMARY.

The various phases of volcanic eruptions illustrated by the Cinder 

Buttes and by the Jordan, Diamond, and Bowden craters are such as 

pertain in general to volcanoes which, for the most part, discharge 

highly liquid lava. At each of these volcanic centers it seems that 

the first eruptions were of the explosive type, and that the elevations 

produced by the accumulation of projectiles whether solid, plastic, 

or liquid first formed were, to a considerable extent, and in some 

instances completely, buried by the subsequent quiet effusion of vast 

quantities of liquid lava. Among the more interesting of the minor 

phenomena associated with them are the craters which were built of 

ejected angular fragments which were blown out from the cooled and 

rigid lava at the summits of the volcanic conduits, and similar struc-
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. XII

J.. FISSURED PAHOEHOE LAVA, JORDAN CRATERS, OREGON.

JS. AA LAVA SURFACE, CINDER BUTTES, IDAHO.
U. S. GEOLOGICAL SURVEY iULLETIN NO. 217 PL. XIII

MARGINS OF LAVA FLOWS, CINDER BUTTES, IDAHO.
RUSSELL.] TEETIAEY FORMATIONS. 59

tures formed of material which was ejected in various conditions 

ranging from extreme viscosity to liquidity, and which formed scoria, 

bombs, lava cakes, and splashes of lava which became confluent 

after falling. The elevations built by the accumulation of such projectiles range, as has been stated, from lapilli cones or craters, due 

to the piling up. of solid angular fragments, through similar craters 

composed in part or perhaps wholly of clots of plastic lava, volcanic 

bombs, and lava cakes to driblet cones and "ovens." The range in 

angle of slope on the exterior of these structures is from the neighborhood of 30° for the loose angular fragments to nearly vertical for 

the adhering clots; the range in slopes of the interior of the crater 

walls is about the same as for the exterior. When the driblet cones 

are roofed over, their inner slopes, both on the outside and within, 

pass beyond the vertical and approach the horizontal.

The lava flows also present a wide range in the resulting details, 

such as typical pahoehoe (PI. XII, A) with corrugated surfaces, and 

even hollow folds due to the influence of an underflow beneath a 

plastic crust, and equally typical aa (PI. XII, J5), due to the breaking 

of a rigid crust on account of the energetic flow of still liquid lava 

beneath it. The occurrence of lava gutters (PL.XIV) and the presence, in numerous instances, of prominent pressure ridges on the 

recent lava sheets (PI. XV, J5) are also instructive features. The thin 

margins of liquid lava streams and the conspicously abrupt and rugged 

extremities of highly viscous lava flows are illustrated on PL XIII.

All the material extruded from the volcanoes described above is 

basalt, and represents the more easily fusible of lavas.

In many ways these modern volcanoes serve to illustrate the nature 

of the far larger outporings of molten rock which, on cooling, formed 

the Snake River Plains and the still vaster, but, in part at least, 

somewhat differently erupted Columbia River lava. In a general 

discussion of volcanoes the Cinder Buttes, etc., maybe considered as 

representing volcanoes of the quiet type, or such as erupt without 

energetic explosions, but their periods of activity were in all cases, so 

far as can be judged, initiated by explosions sufficiently violent to 

blow out projectiles, which on falling formed conspicuous elevations. 

They may be considered, therefore, as furnishing a connecting link 

between volcanoes of the explosive and those of the quiet type. These 

intermediate examples indicate, as has long been recognized, that the 

classification of volcanoes under two types, viz, explosive and quiet, 

is largely for convenience and that no sharply defined boundary separates the two.

TERTIARY FORMATIONS.

Besides the products of recent volcanoes, briefly described in the 

preceding pages, there are, in the portions of Idaho and Oregon under 

consideration, widely extended sheets of rock which may be classified 

according to their mode of origin in two broad groups of terranes, one 

of which includes the rocks composed of material that was deposited
60 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BTJLL. 217.

by water and the other the rocks which have cooled from a molten 

condition. The former includes the material laid down in lakes and 

by streams, aided in each case in a minor way, no doubt, by the 

transporting action of the wind; and the latter embraces the various 

products of volcanoes or volcanic rocks, and the similar magmas 

which have cooled in fissures, below the earth's surface, forming 

dikes. These more general groups of rocks are naturally subdivided 

in reference to mode of origin, composition, etc., as is indicated in the 

following table:

I Conglomerates, sandstones, shales, unconsolidated gravel,

1. Sedimentary rocks-J sand, clay, etc. (together with beds of volcanic dust 

and volcanic gravel or lapilli).

2. Igneous rocks.

a. Volcanic rocks .

b. Dike rocks

Lava flows.

Fragmental

rBasalt. 

\Rhyolite. 

Basaltic scoria, bombs,

products of lapilli, etc. 

volcanoes. Rhyolitic lapilli and

dust.

Magmas like the molten material discharged by volcanoes, but which 

cooled in fissures below the earth's 

surface, forming dikes.

All the rocks referred to above are placed provisionally in the Tertiary division of geological history, excepting, as already noted, in 

the case of certain of the products of volcanoes which are of later 

date, and belong to the Pleistocene and recent times. The sedimentary rocks of Tertiary age also grade into more recent deposits of 

similar character and like mode of origin. At present it is impracticable to designate any well-defined boundary between either the volcanic or sedimentary rocks of the Tertiary and the similar terranes of 

more recent origin. While terranes older than the Tertiary are certainly present, beneath the areas occupied by rocks of that age, they 

are believed not to be exposed at the surface along the route followed 

during the reconnaissance which furnished the data for this report.

SEDIMENTARY ROCKS.

The stratified rocks of the region examined or those composed of 

fragments of older rocks, spread out in layers or strata by the waters 

of lakes and streams comprise conglomerate or pudding stone, sandstones, soft, highly calcareous, usually nearly white, shales, and loose 

gravel, sand, white volcanic dust, and dark usually yellowish volcanic 

gravel or lapilli. These beds were for the most part deposited in 

lakes, and belong to the Tertiary division of geological history.

Examples of the conglomerate and sandstone referred to may be 

seen in the hills near where the Owyhee joins Snake River, in the 

isolated hills near Yale, and in the conspicuous bluffs to the southeast 

of Malheur and Harney lakes, as well as many other localities. These
U. S. GEOLOGICAL SURVEY ULLETIN NO. 217 PL. XIV

LAVA GUTTERS, JORDAN CRATERS, OREGON.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. XV

A. PRESSURE DOME IN RECENT LAVA, JORDAN CRATERS, !_ .._ ,..

,B. PRESSURE RIDGE IN RECENT LAVA, DIAMOND CRATERS, OREGON.
U. S. GFOLOGICAL SURVEY

A. WEATHERING OF THIN SHEET OF BASALT ABOVE SOFT STRATA, MULE, OREG.

It. WEATHERING OF THICK SHEET OF BASALT ABOVE THICK BEDS OF SOFT 

MATERIAL, SNAKE RIVER CANYON, OPPOSITE ENTERPRISE, IDAHO.
RUSSELL.] TEETIAEY FOEMATIONS. 61

rocks are usually dark yellow, but occasionally, as near Narrows, are 

nearly white, and in some instances are sufficiently compact to be 

used for building stone. . Associated with the layers of consolidated 

.pebbles and sand just referred to, and having a wide extent in both 

Idaho and Oregon, are soft unconsolidated light-colored shales and 

marls and thick beds of nearly white sand and light-colored clay. 

Beds of this general nature aggregating more than a thousand feet 

in thickness underlie the Snake River between Glenns Ferry and 

Weiser and form the conspicuous white bluff along each side of that 

stream. Similar beds occur also in the lower portion of the valley of 

Malheur River and beneath the rim rocks of the canyons on the west 

slope of Stein Mountain. Light-colored and in part greenish shales 

outcrop on the west side of Alvord Valley, where they pass beneath 

the sheets of basalt, forming the bold eastern face of Stein Mountain. 

Fine exposures of rain-sculptured lacustral sediments, usually of a 

peculiar light-greenish tint, occur on the border of Owyhee River, 

near the mouth of Jordan Creek (PI. XVIII). Similar beds are 

present also in the mountains of Owj^hee County, Idaho, and are a 

southward extension of the thick sediments exposed along Snake 

River. This same formation extends northward from Snake River 

and is exposed near Boise and in the valley of Payette River. From 

its abundant exposures along the last-named stream it has been 

named by Waldemar Liudgren the Payette formation.

While the Payette formation has a wide extent in Or.egon, and possibly reaches to the John Day River, where other similar beds outcrop 

and have been independently named, it is not positive that all the 

exposures of similar material as far south as Harney and Silver lakes 

were deposited in the same lake basin. The lacustral sediments 

beneath the basalt of Stein Mountain reveal a thickness of fully 

1,000 feet, and, as seems probable, are of. older date than the Payette 

formation.

Interbedded with the sandstone and shale, of the formations just 

mentioned, and frequently forming a considerable and at times 

seemingly the major part of their thicknesses, are beds of exceedingly 

fine white volcanic dust. This dust was blown out of volcanoes 

while in a state of violent eruption, and, falling in lakes, or being 

washed into them by streams, became interbedded with other sediments or intimately commingled with them. Examples of pure 

white volcanic dust from 10 to 20 or more feet thick may be seen 

in the hills on the lower course of Owyhee River, a few miles south of 

Owyhee, and are also splendidly exposed near Beulah (PI. XVII). 

Outcrops of material of the same nature, conspicuous on account of 

their whiteness, occur beneath the rim rock near Diamond, in the 

borders of the small valleys in the northern portion of Owyhee 

County, Idaho, as well as at a large number of localities in the bluffs 

bordering Snake River.
62 GEOLOGY OF SW. IDAHO AND SE. OKEGON. [BULL.217,

An interesting fact in connection with the stratified beds briefly 

described above is that they contain the bones of animals which are 

now extinct, but which lived in large numbers in and about the 

ancient lakes in which the sand, clay, volcanic dust, and other rocks 

now exposed and eroded into hills and valleys were deposited. In 

these same beds, but most abundant in the thinly laminated white 

silts and sheets of fine volcanic dust, occur fossil leaves, frequently 

in great abundance, and less commonly the fruits of the plants to 

which they belonged.' These plant remains differ from the vegetation living on the earth to-day, and reveal the nature of the luxuriant 

forests that flourished in the now arid portions of the far West during the Tertiary period of geological history. The fossil bones and 

impressions of leaves and fruits referred to are of great scientific 

interest, as they furnish evidence in reference to past climatic changes 

and the gradual evolution of life on the earth, and also enable geologists to determine the relative age of the beds in which they occur.

Small collections of beautifully preserved fossil leaves were obtained 

from beds of fine white silt near Beulah, in the northwestern portion of 

Malheur County, Oreg., and from well-exposed and in part indurated 

sediments of Lake Payette, on Succor Creek, in Oregon, about 2 miles 

west of Rockhill, in Idaho. These specimens have been studied by 

F. H. Knowlton, paleobotanist of the U. S. Geological Survey, from 

whose manuscript report the following facts and interpretations of 

their meaning have been taken:

"The fossil plants collected contain, in addition to several species 

not as yet described, examples of broad-leaved trees, such as the oak 

(Quercus), of which there are several species, maple (Acer), plane 

tree or button wood (Platanus), willow (Salix), together with representatives of the bearberry (Barberis), wax-myrtle (Myrica), senna 

(Cassia), and others. . The genera of plants represented are nearly all 

still living in America, but the species and varieties differ almost 

wholly from their modern descendants. The genera named above, as 

will at once be recognized by the inhabitants of the arid portions of 

Idaho and Oregon, are not now characteristic of that region. The 

leaves discovered in the rocks indicate that the trees and plants on 

which they grew required a more humid and in general less 'changeable climate than now prevails where their fossil remains are entombed. 

The nearest analogy of the flora they represent is seemingly furnished 

by the varied and beautiful vegetation of the Lower Mississippi Valley. 

Among the most conspicuous of the leaves spread out in the finegrained lacustral sediments, in which they have been preserved for 

countless years, as if in the presses of an herbarium, are broad, 

strongly-veined, deeply-lobed leaves of an ancient maplej and in association with them are finely preserved winged seeds belonging to the 

same genus and possibly the same species. Several species of oak, 

etc., show that the uplands were clothed with hardwood trees, inter-
U. S. GEOLOGICAL SURVEY BULLETIN NO. 217 PL. XV

EXPOSURES OF VOLCANIC DUST OF TERTIARY AGE, NEAR BEULAH, OREG.
EXPOSURES OF TERTIARY LAKE BEDS, OWYHEE RIVER, OREGON.
RUSSELL.] TERTIAKY FOKMATIONS. 63

spersed among which were evergreens, as may be judged from the 

evidence furnished by impressions in the rocks of the cones of Q-liJptostrobus, a genus of conifers not now found living in America, but 

still surviving in China." The species from this varied and beautiful 

flora identified by Knowlton are as follows:

FromBeulah: Acer, sp. ?; Cassiaobtusa? Knowlton; Q-lyptostrobus? 

species probably new; Salix day ana Knowlton; Salix perplexa Knowlton. From Succor Creek: Acer sp. ? Berberis simplex Newberry; 

Myrica lanceolata Knowlton; Quercus breweri Lesquereux; Quercus 

. consimilis Newberry; Quercus simplex Newberry; Quc.rcus sp, near 

Q. idahoensis Knowlton; Platanus aspera Newberry; Sapindus sp-. ? 

and several apparently new species.

From the evidence furnished by these fossils, it appears that the. 

plant-bearing beds on Succor Creek are a part of the Payette formation, named and described by Waldemar Lindgren, a which is now 

placed in the Upper Eocene instead of Upper Miocene as formerly. 5 

.The plant-bearing beds at Beulah are younger than the Payette, and, 

although the evidence is not all that could be wished, are referred to 

the Upper Miocene (corresponding with the Mascall beds of Merriam, 

in John Day Valley, Oregon).

The significance of the fossil plants catalogued above can perhaps 

be best suggested to the general reader by directing attention to an 

instructive, but now nearly forgotten, essay on the ancient lakes of 

the western portion of the United States, by J. S. Newberry, c one of 

the distinguished pioneers who made known the marvels of the Pacific 

mountain region.

The graphic pen picture given in the following quotation applies to 

the now arid valleys of Idaho and Oregon, in which the plant-charged 

sediments of ancient lakes are preserved, and should serve to awaken 

a deep interest in the minds of the people inhabiting that region in 

reference to the history of the-land of their birth or adoption.

The pictures which geology holds up to our view of North America during the 

Tertiary ages are in all respects but one more attractive and interesting than 

coiild be drawn from its present aspects. Then a warm and genial climate prevailed from the Gulf to the Arctic Sea. The Canadian highlands were higher, 

but the Rocky Mountains lower and less broad. Most of the continent exhibited an 

undulating surface, rounded hills and broad valleys, covered with forests grander 

than any of the present day, or wide expanses of rich savannah, over which roamed

"Descriptions of the Payette formation, together with discussions as to its geological age, may 

be found in the following publications by Waldemar Lindgren: The mining districts of the 

Idaho Basin and the Boise Ridge, Idaho: Eighteenth Ann. Rept. U. S. Geol. Survey,pt. 3,1898, pp 

617-736; The gold and silver veins of Silver City.De Lamar,and other mining districts in Idaho: 

Twentieth Ann. Rept. U. S. Geol. Survey, pt. 3, 1900, pp. 65-256; The gold belt of the Blue Moun. 

tains of Oregon: Twenty-second Ann. Rept. U. S. Geol. Survey, pt. 2, 1903, pp. 551-776.

6 The evidence which necessitated a revision of the conclusions presented in the papers by 

Lindgren, just referred to, in reference to the geological position of the Payette formation, is 

presented by F. H. Knowlton in Bull. U. S. Geol. Survey No. 204.

cThe ancient lakes of Western America; their deposits and drainage: Preliminary report 

of the U. S. Geol. Survey of Wyoming and portions of contiguous Territories, by P. V. Hayden, 

Washington, 1872, pp. 338-339.
64 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BULL. 217.

countless herds of animals, many of gigantic size, of which our present meager fauna 

retains but a few dwarfed representatives. Noble rivers flowed through plains 

and valleys, and sea-like lakes, broader and more numerous than those the continent now bears, diversified the scenery. Through unnumbered ages the seasons 

ran their ceaseless course, the sun rose and set, moons waxed and waned over this 

fair land, but no human eye was there to mark its beauty nor human intellect to 

control and use its exuberant, fertility. Flowers opened their many-colored petals 

on meadow and hillside and filled the air with their perfumes, but only for the 

delectation of the wandering bee. Fruits ripened in the sun, but there was no 

hand there to pluck nor any speaking tongue to -taste. Birds sang in the trees, 

but for no ears but their own. The surface of lake or river was whitened by no 

sail, nor furrowed by any prow but the breast of the waterfowl, and the farreaching shores echoed no sound but the dash of the waves and the lowing of 

the herds that slaked their thirst in the crystal waters.

Life and beauty were everywhere, and man, the great destroyer, had not yet 

come; but not all was peace and harmony in this Arcadia. The forces of nature 

are always at war, and redundant life compels abundant death. The innumerable 

species of animals and plants had each its hereditary enemy, and the struggle of 

life was so sharp and bitter that in the lapse of ages many genera and species were 

blotted out forever.

The herds of herbivores which included all the genera now living on the earth's 

surface, with many strange forms long since extinct formed the prey of carnivores commensurate to these in power and numbers. The coo of the dove and 

the whistle of the quail were answered by the scream of the eagle, and the lowing 

of herds and the bleating of flocks come to the ear of the imagination mingled 

with the .roar of the lion, the howl of the wolf, and the despairing cry of the 

victim. Yielding to the slow-acting but irresistible forces of nature, each in succession of these various animal forms has disappeared, till all have passed away 

or been changed to their modern representatives, while the country they inhabited, by the upheaval of its mountains, the deepening of its valleys, the filling 

and draining of its great lakes, has become what it is.

IGNEOUS ROCKS.

Volcanic rocks. The rocks which came from volcanoes are by far 

the most conspicuous of any of the formations in southwestern Idaho 

and adjacent portions of Oregon, and are apparently of greater extent 

and thickness than the associated sedimentary beds. They may, with 

sufficient accuracy for the purpose in hand, be classified as basalt and 

rhyolite, but a more critical study than has as yet been practicable 

will perhaps show that each of these divisions, and particularly the 

one here termed rhyolite, includes material that can with greater propriety be otherwise classified.

Both the basalt and the rhyolite present two conspicuously different phases, due to the manner in which the material was spread out 

on the earth's surface. In each case the rock while molten was in 

part extruded by volcanoes so as to form sheets which, in many 

instances, flowed far and wide over the surface of the land before cooling; and in part the lava while yet in the conduits cooled sufficiently 

to become rigid and was shattered by steam explosions. The fragments thus produced were blown into the air and widely distributed
RUSSELL.] TEETIAEY FOEMATIONS. . 65

through the action of the wind, as sheets of volcanic dust, volcanic 

gravel, or lapilli, and angular, fragments frequently of considerable 

size. .

The basalt was spread over the surface of the land mostly in a 

molten and even highly fluid condition,, and the-beds of fragmental 

material produced are relatively small; while the rhyolite ifco a great 

extent was shattered at the time it was erupted, and the resulting 

beds of fragments were probably of greater extent and thickness than 

the sheets of the same material which were spread out as lava flows.. 

This difference in the behavior of the volcanoes from which the comparatively fusible basalt was erupted, and of the volcanoes from which 

the more refractory rhyolite was discharged, is of much significance 

in reference to the nature of volcanoes, but can not be discussed at 

this time.

The basalt is a black, compact rock, but is frequently cellular on 

account of the presence of steam cavities, and in many localities is

columnar. In the region under review it occurs in widely extended 

sheets which in general vary in thickness from about 20 to 80 feet. 

Fine examples m&y be seen all along Snake. River, but more especially on the northern side of its canyon, in the canyon of Bruneau 

.River, and in the hills and mountains of Malheur and Harney counties, 

Oreg. The finest exposure of basalt in the region visited by me in 

1902, if not the most remarkable in the world, is to be seen in Stein 

Mountain. The eastern slope of that splendid mountain is composed 

of the broken and eroded edges of sheets of basalt, which dip westward at an angle of about 3° and present an aggregate thickness of 

not less than 5,000 feet. Between the sheets of basalt, as already 

noted, there are in at least 18 instances beds of coarse sandstone, 

varying in thickness from a few inches to 6 feet. Where the beds.of 

sandstone occur the sheets of basalt are in general about 60 feet thick. 

From this and other similar evidence the total number of lava flows 

which occur in Stein Mountain is estimated at between 80 and 100.

The widely extended sheets of basalt just referred to, like the sedimentary beds with which they are intimately associated the sheets 

of basalt and the beds of sandstone, shale, clays, etc. belong prin- 

' cipally to the Tertiary period of geological history and, as seems evident, form the lowest member of the widely distributed formation 

termed the Columbia River lava. Volcanoes have been active, however, in Idaho and Oregon at intervals from the time the oldest sheets 

of basalt were poured out in a molten condition down to almost the 

present day, as is shown by the Cinder Buttes, Jordan Craters, and 

other volcanic features already briefly described.

The rhyolite, like the basalt, occurs both as massive sheets, formed 

by the cooling of molten rock, and as fragmental deposits, which also 

form well-defined beds. Of the layers of .rock originating in these two 

ways, the sheets composed of angular fragments, now in many

Bull. 217 03 5
66 GEOLOGY OF SW. IDAHO AND SB. OEEGON. [BULL.217.

instances firmly cemented, and forming a rhyolite tuff, are far more 

numerous and more extensive than the associated rhyolitic lava sheets. 

The beds of white volcanic dust described above as forming a part of 

the sedimentary deposits are composed of the finest of the fragments 

blown into the air by the volcanoes from which came the material 

now forming the sheets of rhyolite and of rhyolitic tuff.

The compact massive rhyolite is lighter colored than basalt, and in 

Idaho and Oregon is usually purplish on fresh, surfaces, but weathers 

to a rich brown or red. It contains conspicuous crystals and grains 

of quartz, feldspar, and other mineral, and hence usually appears 

spotted. Frequently the crystals, and grains referred to exhibit a 

linear arrangement, such as would be produced by a flowing motion 

in the glassy base in which they were embedded. At times the molten 

material cooled too quickly for crystals to form and produced a compact black glass, termed obsidian, fragments of which occur thickly 

over hundreds of square miles in eastern Oregon.

The rhyolitic tuff is composed of angular fragments of the rock just 

describedj which, in most instances, are firmly cemented, so as to form 

sheets that are nearly, if not fully, as resistant to atmospheric conditions as the rock which cooled from fusion without being shattered, 

and frequently forms "rim rocks" on the sides of canyons and 

valleys.

Extensive exposures of rhyolite and of rhyolitic tuff occur in the 

mountains on the northeast side of Harney Valley, sometimes termed 

the Crow Creek Mountains. The conspicuous rim rocks on each side 

of Rattlesnake Creek, near Harney, are of rhyolitic tuff, while certain 

of the beds lower down in the walls of the same canyon, usually cavernous on the weathered outcrops, are of rhyolite, which has a peculiar concentric or spherulitic structure. Again, in the bluffs of Silvies 

River, to the west of Burns, the edges of a thick sheet of compact tuff 

are well exposed, and similar rock has a wide distribution in the 

forest-covered mountains in which Silvies River rises. Other outcrops of tuff and of compact rhyolite occur about Silver Lake at Iron 

Mountain and in the Mahogany Mountains. The conspicuous rim 

rocks in the vicinity of Diamond are composed of tuff, and similar 

rock has a wide distribution in the hills near Smith and Mule.

An interesting fact in connection with the sheets of rhyolite and of 

rhyolitic tuff in southeastern Oregon is that they are younger than 

much of the basalt of the same region, and overlie it. There have 

been eruptions of basalt also since the youngest observed sheet of 

rhyolite or of rhyolitic tuff was spread out, as rim rocks of basalt 

above the thick deposits of rhyolitic tuff are of common occurrence.

Dike rocks. The molten magmas which rise in volcanoes and in 

part overflow, so as to form lava sheets, also in part cool below the 

surface in the conduits of volcanoes and in fissures. Many distinctive features in the rocks produced from the same molten magma arise 

in this way, which it is unnecessary to consider at this time.
BUSSELL.] STEUCTUEE. 67

Both the basalt and the rhyolite which form such extensive outflows 

in Idaho and Oregon came to the surface through openings, as fissures, 

for example; and below the present surface it is to be expected that 

there are many fissures in which molten rock has cooled so as to form 

what are termed dikes. A few dikes were observed in the bold 

eastern face of Stein Mountain, and indicate what may be present in 

other localities. The dikes referred to are nearly vertical, vary in 

width from 20 to 60 feet, and are horizontally columnar. As is well 

known, dikes have frequently led to the hardening of the walls of the 

fissures they occupy, and for this and other reasons their presence in 

an artesian basin might introduce serious difficulties in the way of 

obtaining flowing wells. If in drilling a well the locality chosen should 

chance to be directly above a dike, it is probable that the well would 

be a failure, even if the difficulty of penetrating the usually compact 

and hard rock of the dike could be overcome. Where the country 

rock is concealed beneath deep sheets of soil, alluvial deposits, etc., 

it is frequently impossible to detect the presence of a dike in the rocks 

beneath the surf ace-cover ing, unless they are encountered in drilling 

or making other excavations. So far as can now be judged, however, 

the dikes in the artesian basins described in this report are not numerous, and the chances of striking them in drilling are small. A greater 

danger lies in the fact that they may cut a water-bearing stratum, so 

as to prevent the percolation of water through it.

STRUCTURE.

By geological structure is understood, in part, the positions occupied by stratified or bedded rocks in the earth's crust. For example, 

sandstone, shale, etc., originally laid down in horizontal sheets, are 

now found to be inclined, folded, and in many instances occupy a 

vertical position.

The rocks, both sedimentaiy and volcanic, which underlie southwestern Idaho and southeastern Oregon, were at the time of their 

formation spread out in nearly horizontal layers, but subsequently 

they have been depressed in one locality and raised in another, and 

in certain instances crushed together so as to form great upward and 

downward folds. In other instances they have been broken along 

nearly vertical planes, and the portion of the strata on one side of 

the break upraised or depressed in reference to the corresponding 

strata on the opposite side; that is, have been faulted. Examples of 

the gentle tilting of previously horizontal sheets of rocks throughout 

great areas are furnished in the broad Snake River Plains between 

Glenns Ferry and Owyhee. North of Snake River the rocks are 

now gently inclined upward to the north, but south of the river the 

same beds rise when followed southward, and in the Owyhee Mountains are more than a thousand feet above the position the same 

strata occupy beneath Snake River. This uptilting of stratified beds 

is well displayed in the hills near where Snake River first crosses the
68 GEOLOGY OF SW. ID.AHO AND SE. OKEGON. [BULL.217.

Idaho-Oregon boundary. These remnants of formerly much more 

widely extended strata indicate the great amount of denudation that 

has occurred throughout an extensive region.

Broad and comparatively gentle elevations and depressions of the 

once horizontally stratified rocks occur also in other portions of the 

region examined, as, for example, in the neighborhood of Harney and 

Burns. The rocks beneath the extensive valley in which Malheur 

and Harney lakes are situated slope upward in the hills and mountains about the borders of the basin, as is well shown in the walls of 

the canyons on the west side of Stein Mountain, in the Crow Creek 

Mountains, on the border of the canyon of Rattlesnake, in the hills 

to the west of Burns, and at several other localities in the same region. 

In general, all about the Harney Basin as it is convenient to term 

the great depression in which Malheur and Harney lakes are situated, 

and of all of the country drained by them the rocks are upraised. 

This basin, however, is not a simple saucer-shaped depression, but has 

irregularities, and is due to the association of several upheavals and 

depressions. The broad, gentle undulations in the rocks just referred 

to are, in some instances, a hundred or more miles across, and are 

promising structural features in reference to the hope of obtaining 

an artesian water supply.

In addition to the broad and usually somewhat indefinite swells 

and depressions referred to above, and others of similar nature but of 

smaller size, are certain well-defined upward folds or anticlines, and 

equally characteristic downward folds or synclines. These are similar 

in shape and analagous in the manner in which they were produced to 

the folds or corrugations that may be made by pushing one side of a 

pile of rugs toward its center, or, on a still smaller scale, by forcing 

together the sides of a pile of newspapers so as to compress them into 

folds. In the region under consideration there are several examples 

of such folds, but, as is commonly the case on all land areas, the 

relief of surface produced in the manner referred to has been greatly 

modified by erosion. The upward folds particularly have been cut 

away, leaving for the most part only their basement portions.

A striking illustration of a great upward bend, involving bedded 

lava sheets with an aggregate thickness of fully 5,000 feet, and also 

a great but unknown thickness of stratified sedimentary deposits 

beneath them, is furnished by the northern portion of Stein Mountain and the several parallel nearly north-south ridges to the east 

of it, and north of Alvord Desert. The larger features of the rugged belt of country referred to are seemingly due to the erosion of 

a great anticlinal fold, the longer axis of which trends about northeast and southwest, but this conclusion is here stated tentatively, 

as sufficient time was not available for more than a hasty examination of a part of the region. The hard layers of compact basalt in 

the truncated remnant of the fold now form the sharp-crested ridges
PETROLEUM. 69

to the east of Juniper and Mann lakes, which have a gentle surface 

slope on one side and a steep escarpment on the other.

A characteristic example of a broad downward fold or syncline may 

be see.n from the summit of Stein Mountain on looking so.uthwest 

over the region drained by Donner and Blitzen River. The longer 

axis of this basin trends in a north-south direction, and is inclined 

downward or pitches north ward.

Accompanying the deformation of .rocks, breaks sometimes occur, 

and the edges of the broken layers on the opposite sides of a fracture 

are upheaved or depressed with reference to each other. In this and 

yet other ways what are termed faults are produced.

Breaks in the earth's crust of the nature just referred to, Avhen they 

affect the relief of the surface, produce bold escarpments. The strata 

frequently dip away at gentle angles, thus producing what it is convenient to term mouoclinal ridges or mountains that is, elevations 

Avith steep descents on one side and gentle slopes, corresponding 

^closely with the inclinations of the component beds, on the other. 

Examples of such monocliual mountains are furnished, as seems evident from such studies of them as it has been practicable to make, by 

Stein Mountain and Mahogany Mountain, in Oregon.

MINERAL RESOURCES.

PETRODEUM.

Search for petroleum has been carried on in the vallej^ of Snake 

River in southwestern Idaho and adjacent portions of Oregon, but 

these attempts have proved failures so far as the discovery of the 

material sought is concerned. In all of the instances referred to that 

have come under my notice, it is!evident that little if any study of the 

geological conditions was made previous to drilling, and little if 

any appreciation of the conditions governing the accumulation 

and storage of petroleum seems to have been entertained by the 

persons who "promoted" the various oil ventures. As much time 

and money has been spent in the region mentioned in fruitless attempts 

to discover petroleum, and as additional efforts will no doubt be made 

in the same direction, more conservative methods may perhaps be 

favored if a plain statement of the general principles pertaining to 

the occurrence of petroleum, and of gas with which it is commonly 

associated, be laid before the reader.

CONDITIONS FAVORING THE NATURAL STORAGE OF PETROLEUM AND

ROCK GAS.

The geologist in searching for oil and gas pools, as subterranean 

accumulations of petroleum and natural or rock gas are commonly 

termed, must of necessity be guided mainly by the physical properties of these substances; by the occurrence of water, with which they
70 GEOLOGY OF SW. IDAHO AND SE. OEEGON. iBULL.217.

are commonly associated; and. by the characteristics of the strata in 

which they occur. An attempt is here made to state in nontechnical 

language the conclusions that have presented themselves in reference 

to the natural storage of petroleum and gas, as search for these 

substances has been carried on in various, parts of the world. No 

originality is claimed for what follows, as it is simply a rearrangement 

of widely current knowledge.

The physical properties of petroleum, gas, and water are well 

known, and of these properties the ones of special significance to the 

geologist are their specific gravities. The specific gravity of petroleum in most all instances is below 1 that is, it is lighter than an 

equal volume of water. The range in specific gravity for American 

petroleum is from about 0.771 for the highly liquid yellow or ambercolored varieties to 0.945 for the thicker and frequently black material, valued principally as a lubricant. The only instance known, so 

far as the writer is aware, of petroleum wmch is heavier than water 

is that obtained at. Zante, in Greece, which has a specific gravity of 

1.02. Natural gas is far lighter than the lightest petroleum, its density being about one-half that of air. The principal physical differences between petroleum and gas are those that constitute the 

distinction between a liquid and a gas. The gas has the property of 

indefinite expansion, and when put under pressure diminishes in volume, at the same time acquiring greater expansive energy or tension.

It is the occurrence in nature of petroleum and gas with these widely 

different physical properties, and each of them lighter than water, 

with which they are usually associated, that the geologist has to consider. Not only this, but attention needs to be given to the occurrence of these substances singly or together, and of one or both of 

them in association with water. The physical properties of petroleum 

and gas thus determine some of the conditions on which success in 

the search for commercial quantities of these substances depends..

If water, petroleum, and natural gas be placed in a corked bottle 

and the receptacle be allowed to rest for a brief time, they arrange 

themselves in the order of their respective specific gravities, the water 

being at the bottom, the petroleum next above, and the gas at the 

top. This conclusion is self-evident, and there is no reason for thinking that the law it illustrates is violated when the three substances 

named are present in a cavity in the earth, or what is much more 

common, contained in the pores of a loose-textured rock. Then, too, 

the water present in the rocks is never pure, but contains more or less 

mineral matter in solution, and not infrequently it is highly saline. 

Its specific gravity is, therefore, greater than if it was pure, and its 

ability, under certain conditions, to displace petroleum and cause it 

to rise is correspondingly increased.

The displacement by water of petroleum contained in the pores of 

rock has certain limitations, however, which at times become important. Petroleum in porous rocks adheres to the surfaces with which
BTJSSELL.] PETROLEUM. l

it comes in contact, this tendency being greater in the heavier than 

the lighter varieties, and may be only in part or not at all displaced 

by water. If the oil refuses to flow under the pressure of water, 

however, it can not be separated except by methods which at present 

are commercially impracticable.

Another important consideration in reference to the occurrence of 

petroleum and gas in .the interstices of rocks, is the porosity of the 

rocks themselves. It has been shown by wide experience that water, 

petroleum, and gas, as they occur in the rocks, are generally contained 

in the small interstices and minute cavities between the grains or 

crystals, and not in caverns or open fissures. This is the nearly universal rule, not only in reference to water in artesian basins, but also 

for petroleum and gas in practically all the areas where they occur. 

Although cistern-like bodies of these substances may exist, they are 

certainly rare, and their presence beneath the surface can not be 

foretold. Their accidental discovery by the drill is a lucky chance.

The porosity of rocks varies through all degrees, from loose sand, 

which may absorb one-half or more of its own volume of oil, to dense, 

compact quartzite, granite, and limestone, which are practically 

impervious.

The three substances under consideration are contained in porous 

rocks in the same manner that water is held in a sponge or in a brick, 

and in the same manner, also, that water passes through a sponge or 

may be forced under pressure through a brick, so petroleum percolates or flows through porous rocks.

The conditions under which water, petroleum, and gas exist in 

porous rocks may be illustrated by packing a bottle with sponges and 

pouring in water and petroleum; the water, being heavier than the 

petroleum, will evidently find its way to the lower portion of the receptacle, and the petroleum will gather above it. If the bottle charged 

in this manner is placed in a warm room, or a gentle heat be applied 

to hasten the process, some of the petroleum will evaporate and form 

a gas, which will rise above the oil. If the application of heat is continued, more and more gas will be generated, and a strong gas pressure be produced. The application of the principle thus demonstrated 

will be considered later.

The porosity of rocks varies, as stated above, but those most commonly charged with petroleum or gas so as to act as reservoirs are 

sandstone, conglomerates, and certain open-textured limestones. It 

must not be concluded, however, that these are the only rocks that 

may act as storage reservoirs in this connection; any rock that has 

an open texture, from whatever cause, may serve the purpose. A rock 

may be crushed and so filled with crevices as to permit of the ready 

percolation of liquids; even volcanic rocks with an open scoriaceous 

texture might fill the role. In general, also, the rocks which permit 

of the passage of petroleum and gas are permeable by water.
72' GEOLOGY OF SW. IDAHO AKD SE. OEEGON. [BULL.217.

The impervious rocks met with in stratified beds, which are the 

usual ones containing water, petroleum, and gas, are mainly shale 

and clay. These rocks were once in the condition of mud and silt, 

and are composed of very small fragments, and, moreover, on account 

of their consistency, are rendered compact by pressure and are frequently impervious even to gases.

The porosity of rocks thus depends on the size and shape of the 

grain, or crystals of which they are composed, and on the nature and 

amount of the cement which unites the grains; the smaller the grains 

and the. more perfectly they are cemented together, the less the size of 

the interspaces between them. Pressure tends to compact the granules of rocks, and the smaller the granules the more thoroughly they 

may be made.to fit together. The search for petroleum and gas, 

therefore, demands a study of the rocks in reference to their porosity. 

As will be shown below, the most favorable conditions, so far as rock 

texture is concerned, occur when a thick kyer of open-textured rock, 

say coarse sandstone, is covered.by a layer of fine-grained rocks like 

shale.. An additional reason why sandstone and certain limestones 

make favorable reservoir rocks, and shales efficient covers for the 

reservoirs, is because the sandstones and limestones are rigid, and if 

fractured or jointed the cracks remain open unless the beds are under 

excessive pressure, while the shales, if fractured, tend to flow, even 

under moderate pressure, and thus close the fissures.

The source of the water with which nearly all rocks near the earth's 

surface are more or less thoroughly charged, is primarily the rain, 

although essentially all stratified beds were deposited in water and 

for that reason were at first water charged, but this primary water 

has in most instances been' flooded out by subsequent underground 

percolation.

The source of the petroleum, as conceded, I believe, by all geologists, 

is organic matter contained in the rocks, but other theories to account 

for its presence have been suggested. The chemistry of the change 

undergone by organic matter when excluded from the air is not well 

known, but the evidence seems conclusive that plant or animal 

remains buried in the rocks, usually in the presence of saline water, 

undergo a slow spontaneous change at low temperatures, one result of 

which is the production of petroleum. A higher degree of heat 

hastens the process, but within moderate limits seemingly does not 

vary the nature of the result.

Petroleum at ordinary surface temperature evaporates and gives 

origin to inflammable gases, and an increase in temperature hastens 

the change, but, except at what may be termed a high degree of heat, 

does not vary the nature of the result. What is of special interest to 

the geologist in this connection is that the evaporation of petroleum 

and the production of gas go on at the ordinary temperatures observed 

in the surficial portions of the earth's crust. As light, highly liquid
RUSSELL.] PETROLEUM. 73

petroleums evaporate, they become more and more dense and change 

to heavy oils; still greater loss by evaporation leads to the production 

of highly viscous substances, like mineral pitch; and a further change 

in the same direction furnishes a large variety of solid hydrocarbons.

In a general way, then, petroleum furnishes natural gas as a " distillate " and viscous and solid hydrocarbons as residues. This is as 

far as we need attempt at present to penetrate the wide and but partially explored field of the origin and chemistry of petroleum and its 

derivatives.

If we assume, as stated above, that petroleum is derived from the 

organic matter contained in rocks, then it follows that we may expect 

to find it in sedimentary rocks of any geological age which were 

deposited after life appeared on the earth. This conclusion is abundantly sustained by the many discoveries of petroleum and gas that 

have been made in rock ranging in age from the lower Paleozoic to 

the Tertiary and even recent time. Any series of stratified rocks, 

therefore, so far as its geological age is concerned, may be expected 

to yield hydrocarbon sin one form or another, and, as has already been 

suggested, even igneous and metamorphic rocks may serve as reservoirs.

Fluids and gases contained in subterranean chambers, or in the 

interstices of porous rocks, are first of all subject to the force of 

gravity. Water in porous rocks will descend under the pull of gravity 

and displace lighter fluids, as well as gases, thus causing them to rise 

if avenues for escape are available. Petroleum alone, in a porous 

rock, will descend and seek the lowest attainable position, although the 

thicker varieties, owing to their high degree of viscosity, would move 

sluggishly.

Hence, water, petroleum, and gas in a porous rock will, as already 

stated, arrange themselves in the order of their respective specific 

gravities, the water being at the bottom and the gas at the top, and 

the water will be subjected to the pressure of the lighter substances 

resting on it. When porous rocks charged with the three substances 

named are confined by impervious beds, so that an escape for the gas 

is impossible, the water and the oil must be pressed on by the gas, 

owing to its tension or expansive force; and should gas continue to 

'be generated, it will acquire such a tension as to exert a great pressure on the fluids imprisoned with it. The fluids and gases contained 

in the rocks may therefore be subjected to gas pressure which, as is 

well known, may equal thousands of pounds to a square foot.

When a porous rock is inclosed between two impervious beds and 

the series is inclined, the natural arrangement of the three substances 

under consideration will be the same as just stated, but under certain 

conditions the petroleum and gas may be brought under hydrostatic 

pressure. To illustrate the requisite conditions for producing hydrostatic pressure, reference is made to the following diagram, which
74 GEOLOGY OF SW. IDAHO AND SE. OKEGON. [BTJLL. 217.

represents a section of the earth's crust, say, 20 miles long and 1,000 

feet deep, where the rocks have been gently folded. In the section 

two bodies of shale are shown, \vith an included layer of porous sandstone. If the sandstone is charged with petroleum and gas generated 

in the shales beneath, or possibly in its own mass, it is evident that 

these light substances will in-part be flooded out by water entering 

where the layer comes to the surface in the eroded fold at the right. 

Under such conditions indications of petroleum and gas should occur 

at a, of the nature of springs of these substances or as a general 

exudation of heavy oil," since the freedom of escape would facilitate 

evaporation of the petroleum and its consequent concentration. The 

petroleum in the porous layer beneath the unbroken fold b would be 

above the water and subjected to a pressure equal to the height of 

the water in the porous layer above the base of the petroleum. An 

'' oil pool" would therefore form beneath the fold b, which would be 

subject to the pressure of the water in the higher portion of the same 

bed. The outcrop of the porous bed, where it receives water, may be 

scores or hundreds of miles distant from the oil pool, and the height 

of the source of water supply scores or hundreds of feet above the

FIG. 1. An ideal geological section' illustrating the manner in which petroleum and natural 

gas accumulate in anticlines, and also the origin of hydraulic pressure on such "pools."

reservoir on which it presses. Gas generated from the petroleum in 

the oil pool beneath b would collect above it and form a gas pool, also 

under hydrostatic pressure. In computing the pressure exerted by 

water in cases like the one just cited, account must be taken of the 

density of the water, -since, if highly saline, its weight will be materially increased. Under the conditions just assumed the oil and gas 

pools beneath b may enlarge until their bases extend laterally below 

the downward fold between a and b, when a limit would be reached, 

as an .avenue of escape through the porous bed to the outcrop at a 

would then be furnished. . Under the conditions shown in fig. 1 a well drilled at b and reaching 

the porous layer would yield gas under pressure, which would escape 

without diminution of pressure until it was exhausted, providing the 

porous .bed was sufficiently open textured to admit of the ready flow 

of water through it, otherwise the gas might escape more rapidly than 

the water could flow in, so as to maintain a constant pressure. After 

the gas had passed off the petroleum would rise in the well to a little 

above the level of a, depending on its specific gravity, and the gas 

well would be transformed into a "pumping" oil well.

Great variations in the sreneral conditions illustrated above occur in
RUSSEU,.] -x PETKOLEUM. 75

nature. The locality a may be much higher than the surface at 6, in 

which case the gas first escaping would be followed by a flow of petroleum, and when that failed, water would follow and form an artesian 

well. Under the conditions shown in fig. 1, wells put down between 

c and a, with the hope of finding either petroleum or gas, must evidently 

result in failure.

Another source of pressure which may be brought to bear upon 

fluids and gases in a porous rock has been suggested, namely, the 

weight of the overlying rocks, but this hypothesis may evidently be 

discarded unless, after the rocks have been charged with water, petroleum, or gas, the weight of the superimposed strata causes compression, which diminishes the volume of the interstices in the porous bed. 

Such a change might evidently take place, but in general must be of 

such small amount in comparison with other causes of pressure on the 

contained fluids and gases that it need not be considered.

Geologists have found that it is not a scarcity of petroleum or gas 

that makes the occurrence of commercial quantities of the substance 

so valuable, but their concentration into what are termed ''pools" or 

natural reservoirs. In this concentration the position in which the

FIG. 2. An ideal geological section illustrating the manner in which petroleum and natural 

gas may be concentrated in horizontal beds.

layers of rock in the earth's crust occur is in the highest degree 

important.

Stratified rocks, when first formed, were in nearly all cases essentially horizontal, but, owing to subsequent movements in the earth's 

crust, are now in many instances variously inclined, folded, and broken. 

In strictly horizontal beds it is evident that the conditions for concentrating the petroleum and gas they may contain are unfavorable. 

This, however, is not equivalent to saying that horizontally bedded 

rocks are of necessity destitute of oil and gas pools. For example, 

as in the section shown on fig. 2, the upper surface of a porous bed 

inclosed between two sheets of shale may be irregular, and the elevations in. its upper surface might supply conditions similar to those 

furnished by an upward fold. In the diagram, oil and gas might 

accumulate at a and b under gas pressure and be of sufficient volume 

to yield valuable returns. Again, in horizontal, impervious beds 

there may occur irregular, porous, masses of rock as sandy patches 

in shale or porous regions in limestone, for example which would 

serve as reservoirs, and on becoming charged with petroleum and gas 

yield one or the other of these substances, according to the shape of 

the pool and the place where it chanced to be penetrated in boring. 

An illustration of such a possibility is shown, to the right in fig. 2.
76 GEOLOGY OF SW. IDAHO AtfD SE. ORfiGOlSf. [BULL.41/.

The influence of an inclination of the strata and of folds has already 

been briefly considered, but the importance of structure, to use a 

general term to designate the position in which the beds occur, is so 

important in the concentration of oil and gas into productive pools 

that it needs to be well understood by all who search for these 

substances.

In many regions the rocks are crumpled or corrugated into a series 

of up and down folds, termed, respectively, anticlines and synclines, 

as shown in fig. 1. Under the structural conditions'there indicated 

it is evident that if petroleum and gas occur in the clotted stratum, 

assumed to be a porous sandstone between two thick beds of shale, 

and water is present, the petroleum will accumulate beneath the 

anticlines, and if evaporation occurs, as is the rule, gas will be 

generated, and both gas and hydraulic pressure will be present. 

These-anticlinal folds, it will be remembered, have a length usually 

much greater than their width, and may measure scores of miles 

in their various dimensions. The longer axes of the folds maybe 

horizontal or inclined, or pitch toward one end or the other. If the 

axes are horizontal it is evident that a well put down anywhere 

along the crest of a fold, as at b in the above cross section, should 

admit of a flow of gas. followed by a rise of oil in the well, or its 

discharge, fountain-like, at the surface, according to "the pressure. 

Should the anticlines have a pitch, however, one end of the fold being 

depressed or the other elevated, with reference to a horizontal plain, 

then it is manifest that the petroleum and gas would be concentrated 

near the upper portion of the pitching anticline and the area of the 

resulting "pool" consequently lessened. Other complexities of structure may be present, as, for example, where one series of folds crosses 

another series, thus producing conditions favoring the accumulation 

of several relatively small pools. Sometimes the rocks, instead of 

being folded into long, narrow anticlines, are elevated in certain 

regions so as to assume dome-like forms. A broad, low dome in a 

series of oil and gas charged beds, with the requisite succession of 

porous and impervious strata, would form the ideal conditions for the 

concentration of the substances named.

The conditions briefly explained above form the basis of the wellknown "anticlinal theory" of the occurrence of oil and gas pools, so 

ably worked out by Prof. Edward Orton in Ohio and Prof. I. C. White 

in Pennsylvania and West Virginia.

A variation of the conditions just considered occurs when the strata 

are gently inclined over broad areas, and the rocks are bent along 

certain axes without being folded so as to form true anticlines, but 

produce flat terrace-like areas in a region of gently-inclined beds. 

Such "terraces" or " arrested anticlines" occur in Ohio and have been 

described by Professor Orton. For example, oil-bearing rocks about 

2,500 feet thick enter the Macksburg oil field, dipping gently south-
EUSSELL.] PETEOLEUM. 77

east, at a rate of 20 to 30 feet to the mile, but they suddenly cease their 

descent and for about 3 miles there is no appreciable fall. The amount 

of territory included in the terrace appears to be 15 or 20 square miles. 

Beyond this the regular dip is resumed. It is difficult to understand 

how the petroleum and gas are retained in a "terrace" if it is really 

horizontal, but the conditions regulating the storage of these substances are so delicately adjusted that a difference of a very few feet 

in the height of the top of the porous layer may determine the success 

or failure of a well drilled to it. The difficulty of ascertaining the 

actual position of the surface of the porous layer when gently inclined 

is shown by the fact that a thickness of a thousand feet or more of 

overlying strata has frequently to be penetrated to reach the necessary 

rock. It is well known, however, that the nearly flat areas, as the 

drill shows them to be, in certain regions where the rocks are gently 

inclined in the same direction on each side, sometimes contain commercial quantities of liquid and gaseous hydrocarbons.

In the above consideration of the influence of structure and texture 

on the storage of petroleum and gas we have assumed that water is 

also present in the rocks. While this is the normal and practically 

universal condition, yet it may happen that water is absent from a 

porous layer containing the other two substances named. In the 

absence of water, petroleum would accumulate in the downward folds 

or would descend until arrested by an impervious stratum, and gas 

would occupy the remainder of the porous bed. An increase in the 

amount of gas would be accompanied by an increase in pressure. 

Under these scarcely to be expected conditions, a well penetrating a 

syncline Avould yield oil under gas pressure which might be great, while 

a well drilled in the course of an adjacent anticline would yield gas 

only, the oil not rising unless the relation of the well to the inclination of the porous layer was such that the oil itself could produce 

"hydraulic" pressure. In such a case the flow of petroleum would 

not be followed by water, and when the outflow ceased the well would 

still be filled with petroleum.

Certain modifications or limitations of the general principles above 

stated need to be kept in mind by persons searching for commercial 

supplies of petroleum and gas, lest valuable pools of exceptional 

character be overlooked.

One of the exceptional conditions referred to is the absence of a 

pervious stratum to act as a reservoir or receiver. For example, a 

bed of shale which is impervious too water may be of such a texture as 

to permit of the slow percolation of petroleum and the ready passage 

of gas. Should such an oil-charged shale occur in thick masses, as in 

the Cretaceous system, in the great plateaus, without interbedded 

porous beds and not having an impervious cover, the gases generated 

would pass off, leaving heavy petroleum, which would descend to the 

bottom of the generating layer or until it-was arrested by an impervi-
78 GEOLOGY OF SW. IDAHO AND SE. OREGON. [BULL.217.

ous stratum. A well drilled in such a bed should furnish petroleum, 

but not under pressure. A small but long-continued yield bjr pumping might be expected, the petroleum slowly percolating into the well 

from the adjacent country rock in much the same way that an ordinary surface well is supplied with water. Under the conditions just 

postulated, but petroleum as well as water being absent, a well might 

yield a moderate but long-continued supply of gas.

Another consideration which may perhaps have economic importance is that the presence of petroleum, especially the heavier varieties, in a porous rock retards the passage of water. The outcrop of 

a porous bed, in which heavy oil has been produced by the evaporation of a lighter variety, might seal the pores of the rock and thus 

prevent the inflow of water, and therefore the cessation of the outflow 

of petroleum. These results might come about especially in a warm 

climate and modify the conditions under which petroleum and gas 

are usually stored. The formation of solid hydrocarbons in porous 

beds and in fissures is but a further step in this same direction. 

Bodies of petroleum-bearing sandstone or other rocks above the surface drainage of a region might, on account of the formation of 

viscous or solid hydrocarbons in their superficial portions, be made 

to yield heavy oil if penetrated by horizontal wells.

The opening of fissures communicating with the surface above an 

oil pool is considered fatal to it as a reservoir of commercial value, 

but if the oil is not under hydraulic pressure or if the pressure is not 

sufficient to cause it to overflow and be replaced by water, the petroleum may not rise in the fissure, or if it does rise not reach the surface, and on evaporating, seal the breach and renew the conditions 

favorable for natural storage. Fissures filled with solid hydrocarbons 

may therefore be considered as favorable indications of the presence 

of oil pools in their vicinity. While the conditions under which petroleum and its derivations occur in nature are simple and easily understood, the application of theory to practice is beset with difficulties 

and uncertainties. The information that is wanted is the texture of 

the rocks, the order of their occurrence, and their structure at a depth 

of several hundred or perhaps several thousand feet below the surface, and this, too, when the surface is usually -covered with vegetation and soil, alluvial deposits, and possibly a thick sheet of glacial 

drift. While the geologist is better able than anyone else to judge 

of the conditions to be expected within the earth's crust, it must be 

confessed that the only practicable way to secure the desired facts in 

untried regions, is in many instances, to put down test wells at what 

seem the most favorable localities. One important duty of the geologist is to discourage ventures in regions where the rocks are so greatly 

disturbed and broken that gas or water-tight reservoirs can not exist, 

or when other conditions such as the metamorphism, preclude 

the probability of success. The conditions which have led to the
RUSSELL.] PETROLEUM. 79

accumulation and storage of petroleum and gas are in general the 

reverse of those which lead to the accumulation of water in artesian 

basins. The most promising localities in the search for relatively 

light hydrocarbon, are in upward folds or anticlines and the most 

favorable localities for storing water in the rocks under pressure are 

in downward folds or synclines. This difference in the conditions 

leading to accumulation of oil and water, as an effort has been made 

above to explain; is due to the differences in the specific gravities (or 

weight of equal volumes) of the substances named. If a fluid heavier 

than water should be present in the rocks, the other conditions considered being the same, the water would be forced upward and would 

accumulate in anticlines, and the most favorable localities for searching for artesian water would be in the upward folds, instead of as now, 

in the downward folds.

APPLICATION.

In attempting to apply the principles just considered in Idaho and 

Oregon, it is evident that the search for petroleum should be confined 

to regions where the rocks have been but moderately disturbed, and 

in such regions drill holes should be put down in the crests of anticlinal folds. The downward folds or synclines should be avoided, as 

water is everywhere present in the rocks and all the downward folds 

may be expected to be filled with it. Experience in southern Idaho 

has fully sustained these deductions, and much time and expense 

might have been saved if they had been given proper consideration 

when the search for petroleum began. All of the drill holes thus far 

put down with the hope of obtaining petroleum are located in broad 

synclinal basins, and in nearly all instances have resulted in obtaining a surface flow of water. Even after several artesian wells had been 

obtained, the drilling of holes for petroleum was continued in the 

same basin, as in Snake River Valley, between Guffey and Weiser, 

and uniformly with the same result. Although there has been a total 

failure to obtain petroleum, what in the end will prove to be a much 

more valuable result, so far as the development of the region is concerned, has .been secured, namely, the demonstration of the value of 

the Lewis artesian basin.

While the region crossed by Snake River in western Idaho and the 

adjacent portion of Oregon, in the vicinity of Owyhee, Vale, and 

Ontario, is a broad syncline, nearly flat in its central portion, it does 

not follow that the entire region is a single great fold. There may be 

secondary wrinkles, and beneath the small upward folds, if such are 

present, petroleum and gas might occur, and be under the pressure of 

the water in the broader and in general trough-shaped depression.

The only locality in the Snake River Valley in western Idaho, so 

far as I can judge from the explorations I was enabled to make, at 

which one would be justified in drilling for the purpose of prospecting 

for petroleum, is the southern part of Canyon County, in the vicinity
80 GEOLOGY OF SW, IDAHO AND SE. OBEGON. [BULL.217.

of Pickles Butte. I was not able to visit the region referred to, but 

views of it obtained from a distance suggested that the rocks there 

rise into a small anticline, the longer axis of which trends about northwest and northeast. A careful study of the region referred to should 

show whether an anticline is present or not, and if discovered a drill 

hole put down to a depth of 1,000 or 1,200 feet would furnish a crucial test as to the presence of petroleum or gas. So far as can be 

judged, the Payette formation, which, together with- sheets of basalt, 

underlies the Snake River Plains, is notably free of organic matter, 

and the chances seem to be that even if anticlines or other conditions 

favoring the storage of petroleum or gas are present, but little hope 

of obtaining commercial quantities of these substances can reasonably 

"be entertained. 
INDEX.

Page. 

Aa lava, view of.-......----...--------.--.. 58

Alluvium, occurrence of.................. 19

Alvord Desert, Oregon, location and character of............................ 33-34

Alvord Valley, Oregon, lakes and playas

in................................... 34

location and character of............. 33-34

Andes, snow line in, altitude of........... 12

Anticlines, manner in which petroleum 

and natural gas a'ccuinulate, figure showing....................... 74

petroleum in, occurrence of.......... 76

Artesian basins, hot springs in ........... 25-26

location and extent of................. 25

Artesian wells at Boise, temperature of . 24 

Ascension Island, bomb from structure

of................................... 43

Baker City, Oreg.. weather record at, for

1900...--....-.....-..-.-....-....... 8

Basalt, occurrence and character of...... 65

of Stein Mountain ..................... 15

Beulab, Oreg., fossil leaves collected near. 62 

volcanic dust near, plate showing .... 62

Boise, Idaho, hot springs and wells near. 24 

weather record at, for 1900............ 8

Bombs, volcanic, occurrence, shape, structiire, character, etc.,of............ 40-45

sections of ...---.........-..........:.. 44

views of................................ 40,42

Bowden Crater, Oregon, location, structure, etc.,of........................ 57-58

Burns, Oreg., forest near .................. 10,11

weather record at, for 1900............ 8

California, snow line in. altitude of...... 12

tree growth in, upper limit of........ 11

Caspian Sea, loss of saline matter by..... 31-32

Castlerock, Oreg., forest near ............ 10

Cinder Buttes, Idaho, aa lava at, view of. 58 

cinder cones of, features of........... 45-47

craters among, structure of .......... 39-40

lapilli, cones, and bombs at, views of 40,42,44 

lava flows at, view of margins of..... 58

location of ............................. 38

sequence of events in.................. 45

tuff on lava flow at, view of...........' 38

volcanic bombs of..................... 40-45

Cinder cone, fragment of, view of........ 44

Climate, characteristics of................ 8

Cone, fragment from, view of............ 44

Cones, view of............................. 40

Cow Creek Valley, Oregon, lakes in...... 27-28

Craters. (See Jordan Craters; Diamond 

Craters; Cinder Buttes.)

Bull. 217 03- -6

Page. 

Dana, J. D., reference to....:.......... 45,46,52

Darwin, Charles, quoted on bomb from

Ascension Island .................. 43

Dawson, E. H., reference to .............. 7

Denudation,increase in................... 19-20

Diamond Craters. Oregon, driblet cone tit,

view of............................. 52

location, structure, lava, etc., of..... 54-57

pressure ridge in lava at, view of.... 60

Dike rocks, occurrence and character of. 66-67 

.Dikes of Stein Mountain.................. .16

Dog Mountain, Oregon, efflorescence from

near, analysis of ................... 36

Domes in lava, occurrence of............. 54

view of........................_...... 60

Donner and Blitzen River, Oregon, course

of.....................:.........--.. 22

Drainage, directions of-------------------- 21

Driblet cones, views of ...................' 52

occurrence of...-...----.....-....--... 52

Eolian mounds, occurrence of............ 33

view of................................. 30

Erosion, increase in....................... 19-20

Fissures, effect on storage of petroleum. 78 

Forests, occurrence and extent of........ 9-12

Fossils, occurrence of..................... 62-63

Frost, dates of first and last, i n 19CO...... 8

Garnet, Idaho, weather.record at, for 1900 8 

Gas, conditions favoring storage of petroleum and .......................... 69-80

physical properties of................. 70

Gilbert, G. K., cited on Lake Bonneville. 34 

Grasses, effect of overgrazing on......... 19-20

Grazing, effect of........................... 19-20

Hanging valleys, occurrence of .......... 17

Harney, Oreg., forest near................ 10,11

Harney and Malheur lakes, Oregon,

streams tributary to.............. 22

Harney artesian basin, Oregon, location,

extent, and water supply in ...... 26

Harney Lake, Oregon, existence of, cause

of.-.................---.-.--..-.-..- 22

location, area, and water supply,etc.,

of-.....-.......-.-.--.-....----.---. 29-32

water from, analysis of............... 31

Horizontal beds, petroleum and natural

gas in, concentration of, figure

showing-......-..-----...-.-....--. 75

Hot springs, location of................... 24

Igneous rocks, occurrence and character

of................................... 64-66

Iron Mountain, Oregon, eolian mounds

near, view of....................... 3!)

81
82 INDEX.

Page. 

Jordan Craters, Oregon, domes in lava at,

view of.--...........-.----.----..-. 60

. driblet cone at, view of ............... 52

lakes caused by lava flow from....... 27

lava gutters at, view of--------------- 00

location, age, structure, character,

etc., of .........-..-.. -.-------- ''5-54

pahoehoe la va at, view of ------------- 58

Jordan Creek, Oregon, craters near...... 48

Jordan Valley village, lakes near ........ 27

Juniper, occurrence of.........---.------- 9

Zeiger Creek Canyon, Oregon, features of 16-17

Knowlton, P. H., quoted on fossil plants. 62

Lake beds, exposures of, plate showing.. 62

occurrence of.____......_..._...------- 18-19

Lake Payette, Oregon, fossil leaves from. 62 

Lakes, efflorescences left by__.....-..--.- 35-36

fluctuations of------------------------- 34-35

location of--------.----.------.-------- 27-38

Lapilli, island of, view of.......--....-..- 40

Lava, varieties and manner of extrusion of 37 

Lava flows, view of margins of........... 58

Lava gutters, occurrence and character of 52-53 

views of--........---------------------- 60

Lava streams, tuff floated on.-...--...--- 39-40 

Lewis artesian basin, Idaho, location,

area, and water supply of -------- 25

Lindgren, Waidemar, reference to ...... 61,63

Mahogany Mountain, Oregon, location

and structure of-........--.......- 14

Malheur and Harney lakes, Oregon,

stream in region of, draining to.. 22-23 

Malheur Lake, Oregon, existence of,

cause of-.-.------.-.---..-.-------- 22

location, area, and water supply, etc.,

of ............- . . ...-.29-32

view of south shore of ---.......-.. 30

Malheur River, Oregon, former channel

of ...... -. .. 22

Mexico, tree growth in, upper limit of... 11 

Mineral resources, description of ........ 69-80

Mountains, structure, extent, etc., of.... .13-17

Mule, Oreg., lava dam, former channel of

Malheur Eiver near............... 22

Narrows, Oreg., efflorescence from near,

analyses of-------.................. 36

Newberry, J. S., quoted on life in Tertiary period ..................I..._. 63-64

Orton, Edward, reference to ............. 76

Otis artesian basin, Oregon, location and

area of............................. 25-26

" Ovens," occurrence and character of .. 52 

Owyhee Mountains, structure of......... 14

Owyhee Eiver, Oregon, course of, rocks

exposed on, and reservoir site on. 21

Tertiary lake beds on, plate showing. 62

Pahoehoe lava, view of ................... 58

Fayette, Idaho, weather record at, for

1900................................. . 8

Payette formation, extent and character

of .................................. 61

Petroleum, conditions favoring storage

of .................................. 69-80

physical properties of................. 70-7.1.

source of............................... 72

Pickles Butte, Idaho, petroleum at, possible occurrence of................ 79-80

Page. 

Playas, occiirrence of....... . ..... 32-33

Porosity of rocks, effect on storage of petroleum ............................ 71

Pressure ridge in lava, occurrence of.... 54

view of.. ............................... 60

Rainfall, amount of.....-.....--..--..--.. 8

Rhyolite, occurrence and character of... 65-66 

Ridge in lava, occurrence of.............. 54

Rim rocks, occurrence of................. 13

weathering of plate showing......... 60

Rocks, porosity of, effect on storage cf petroleum............................ 71-72

subdivisions of ......_.....-_..__--.... 60

Russell, I.C., cited 011 laker,...__...___._. 34 

cited 011 recent volcanoes............. 36

Sagebrush, occurrence of................. 9

St. Elias, Mount, Alaska, snow line on,

altitude of ......................... 12

tree growth on, upper limit of -_._-__. 11 

Sedimentary rocks, occurrence and character of ............--.-.--...--.... GO-64

Sheep, overgrazing by, effect of......--.. 19-20

Silver Creek Valley, Oregon, lakes and

playas in........................... 32

Silver Lake, Oregon, location of -.----.... 32

weather record at, for 1900............ 8

Silver Lake Valley, Oregon, vegetation in 33 

Silvies River, Oregon, course of.......... 22

source of-...--------..-..--.....-...... 10

Snake River, Idaho, tributaries of....... 21

Snake River Plains, Idaho, extent and

character of........................ 12-13

Snake River Valley, Idaho, petroleum in,

search for.......................... 69

Snow, amount of....--...---...-......---- 8

Snow line, altitude of ......-----.......... 12

Springs, hot, locations of .-----........... 24

temperature of........................ 23-24

Steiger, George, analysis by ............. 31,33

Stein Mountain, Oregon, anticline in.... 68

basaltof................................ 65

basinseastof ........................... . 23

dikes in..__....................... 67

location,'structure, and stratigraphy

of................................... 14-16

tree growth on ..............".......... 11-12

Streams, character and occurrence of.... 21-23

Structure, discussion of .................. 67-69

Temperature, record of................... 8

Tertiary formations, occurrence and extent of .............................'59-67

Tertiary lake beds, exposures of plate

showing..................._...... 62

Tertiary lakes, deposi ts of................ 18-19

Tertiary period, climate, topographic and

f aunal conditions during.......... 63-64

Timber line,occurrence and altitude of.. 10-12 

Topography, features of .... ..-...'...... 12-20

Trees, growth, upper and lower limits of 10-12 

Tuff, cragsof,view of .................. 38

Turner, Scott, reference to............... 7

Vale, Oreg., hot spring at, temperature of 24 

weather record at, for 1900............ 8

Valleys, character and extent of .......... 12-13

deposits in, features of................ 18-20

hanging, occurrence of. .-.....-.-. 17

Vegetation, characteristics of ............ 9-12
INDEX. 83

Page.

Volcanic bombs, occurrence, shape, structure, character,etc.,of.-.-..---.-... 40-45 

sections of ___...--.......I............. 44

views of........'...........---...-.-. 40,42,44

Volcanic dust, exposure of plate showing 62 

occurrence of--..-.--....--...-..----.. 61-62

Volcanic eruptions, various phases of.... 58-50

Volcanic rocks, occurrence and character 

of..................................

Volcanoes, discussion of ................

Page.

Water, analysis of, from Harney Lake... 3J.

Weather, record of, for 1900, table showing ............................'..... 8

White, I. C., reference to ................. 7l!

Whitehorse artesian basin, Oregon, location and area of..................... : 26

structure of.......,......---..-..-...-- 20

Willow Creek Valley, Oregon, vegetation

in, effector overgrazing on....... 20

Wind, deposits caused by................. . 19

o

PUBLICATIONS OF UNITED STATES GEOLOGICAL SURVEY.

[Bulletin No. 217.]

The serial publications of the United States Geological Survey consist of (1) Annual 

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SERIES B, DESCRIPTIVE GEOLOGY.

B 23. Observations on the junction between the Eastern sandstone and the Keweenaw series on

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B 33. Notes on geology of northern California, by J. S. Diller. 1886. 23 pp. (Out of stock.) 

B 39. The upper beaches and deltas of Glacial Lake Agassiu, by Warren Uphara. 1887. 84 pp., 1 pi.

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B 137. The geology of the Fort Riley Military Reservation and vicinity, Kansas, by Robert Hay.

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B 144. The moraines of the Missouri Coteau and their attendant deposits,' by .1. E. Todd. 1896. 71

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B 158. The moraines of southeastern South Dakota and their attendant deposits, by J. E. Todd.

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B 159. The geology of eastern Berkshire County, Massachusetts, by B. K. Emerson. 1899. 139 pp.,

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B 165. Contributions to the geology of Maine, by H. 8. Williams and H. E.°Gregory. 1900. 212 pp.,

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WS 70. Geology and water resources of the Patrick and Goshen Hole quadrangles in eastern Wyoming and western Nebraska, by G. I. Adams. 1902. 50 pp., 11 pis. 

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I
II ADVEETISEMETSTT.

PP 1. Preliminary report on the Ketchikan mining district, Alaska, with an introductory sketch of 

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PP 2. Reconnaissance of the northwestern portion of Seward Peninsula, Alaska, by A. J. Collier. 

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PP 10. Reconnaissance from Fort Hamlin to Kotzebue Sound, Alaska, by way of Dall, Kanuti, 

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PP 11. Clays of the United States east of the Mississippi River, by Heinrich Ries. 1903. 298 pp., 9 pis.

PP 12. Geology of the Globe copper district, Arizona, by F. L. Ransome. 1903. 168 pp., 27 pis.

PP 13. Drainage modifications in southeastern Ohio and adjacent parts of West Virginia and Kentucky, by W. G. Tight. 1903. Ill pp., 17 pis.

B 208. Descriptive geology of Nevada south of the fortieth parallel and' adjacent portions of California, by J. E. Spurr. 1903. 229 pp., 8 pis.

B 209. Geology of Ascutney Mountain, Vermont, by R. A. Daly, 1903. 122 pp., 7 pis.

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PP. 15. Mineral resources of the Mount Wrangell district, Alaska, by W. C. Mendenhall and F. C. 

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B 217. Notes on the geology of southwestern Idaho and southeastern Oregon, by I. C. Russell. 1903. 

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Correspondence should be addressed to

THE DIRECTOR,

UNITED STATES GEOLOGICAL SURVEY,

WASHINGTON, D. C. 

SEPTEMBER, 1903.
LIBRARY CATALOGUE SLIPS.

[Mount each slip upon a separate card, placing the subject at the top of the 

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Russell, Israel C.

. . . Notes on the geology of southwestern Idaho and 

southeastern Oregon, by Israel C. Russell. Washington, Gov't print, off., 1903.

83, III p. 18 pi. (incl. fold, map), 2 fig. 23f". (U. S. Geological survey.

Bulletin no. 217.)

Subject series B, Descriptive geology, 32.

Russell, Israel C.

. . . Notes on the geology of southwestern Idaho and 

southeastern Oregon, by Israel C. Russell. Washington, Gov't print, off., 1903.

83, III p. 18 pi. (incl. fold, map), 2 fig. 23£cm. (U. S. Geological survey. 

Bulletin no. 217.)

Subject series B, Descriptive geology, 32.

U. S. Geological survey/

Bulletins.

3 no. 217. Russell, I. C. Notes on the geology of southI western Idaho and southeastern Oregon. 1903.

U. S. Dept. of the Interior.

see also 

U. S. Geological survey.