DEPARTMENT OF THE INTERIOR I TED STATES GEOLOGICAL SUE \ ; GEORGE OTIS SMITH, Director Water-Supply Papek 221 GEOLOGY AND WATER RESOURCES OF THE GREAT FALLS REGION MONTANA BY CASSIUS A. FISHER WASHINGTON GOVERNMENT PRINTING OFFICE 1909 OassJJtB 7£5 DEPARTMENT OF THE INTERIOR UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, Director Water-Supply Paper 221 GEOLOGY AND WATER RESOURCES OF THE GEEAT FALLS REGION MONTANA BY CASSIUS A. FISHER WASHINGTON GOVERNMENT PRINTING OFFICE 1909 r V FEB n 13 , D.wl ^N. CONTENTS. Page. Introduction 7 Literature S General statements 8 Bibliography 9 Geography 10 General features 10 Plains province '_ 10 Drainage 11 Detailed descriptions of districts . 11 Geology 14 Stratigraphy 14 General outline 14 Carboniferous system 17 Madison limestone 17 Quadrant formation _v 17 Jurassic system 18 Ellis formation 18 Morrison formation IS Cretaceous system 20 Kootenai formation 20 Colorado formation 22 Montana group 23 Eagle formation 23 Claggett formation 23 Quaternary system 24 Terrace deposits 24 Glacial deposits . 25 Alluvium . 26 Structure 26 Little Belt Mountains 27 Highwood Mountains 27 Lewis and Big Belt ranges 27 Water resources ^_ 28 Source 28 Surface waters 28 Streams 28 Missouri River 28 Sun River ,, 30 Smith River 31 Teton River '_ 31 Belt Creek— 32 Otter Creek 32 Other small streams 32 Lakes and swamps _ __„ 34 3 4 CONTENTS. Water resources — Continued. Page. Underground waters 35 General statements 35 Springs 35 Distribution 35 Giant springs _ 37 Wells 39 List of springs 42 List of wells 50 List of artesian wells 58 Artesian conditions 60 Water supply by districts 61 Geyser district 61 Otter Creek district 63 Great Falls district 63 Missouri River valley district 64 Ulm Bench 64 Area south of Sun River 65 Sun River valley 65 Highlands north of Sun River 66 Fort Benton Bench 66 Teton River valley 67 Burton Bench 67 Muddy Creek artesian basin 68 General description 68 Source 69 Water supply of towns and villages 69 Chemical character of water 71 Analyses of waters 73 Water power 76 Description of falls 76 Utilization 76 Undeveloped power 2 77 Irrigation 78 General statements 78 Sun River valley 78 Teton River valley 79 Other valleys 79 Agriculture 80 Climate 80 Temperature 80 General statements 80 Great Falls region 81 Rainfall 82 Culture 84 Index 87 ILLUSTRATIONS, / Page. Plate I. geologic map of Great Falls region, Montana In pocket. liy A, Dry bed of Belt Creek, near Belt, Mont. ; B, Northwest side of Square Butte, showing Eagle sandstone overlain by igneous rock 12 III. A, View 01 dam at Black Eagle Falls and the\ Anaconda Consoli- dated Copper and Mining Company's smelters, Great Falls, Mont.; B, Rainbow Falls of Missouri River, 4 miles below J the town of Great Falls, Mont 28 IV. A, Crooked Falls of Missouri River, near Great Falls, Mont; B, Big Falls of Missouri River, 9 miles northeast of Great Falls, Mont..... 30 V. A, Spring at base of Colorado sandstone, 12 miles south of Great Falls, Mont; B, Giant Springs, near Great Falls, Mont 36 VI) Map of Great Falls, showing preglacial channel of Missouri River and course of underground water, Great Falls district, / Montana 38 VII. Irrigation, agricultural, and water-resource map of Great Falls re- gion, Montana 62 5 GEOLOGY and water resources of the great FALLS REGION, MONTANA. By Cassius A. Fisher. INTRODUCTION. This report is based on field work done during the season of 1906 in connection with a detailed investigation of the geology and coal resources of the Great Falls coal field. It is designed mainly to fur- nish information regarding the general geology of the region and the prospects for underground water. A brief description of the differ- ent geologic formations is given, with statements concerning their structure, general distribution, and water capacity. The surface waters are also described, including their present and proposed uses for irrigation, water power, etc., and the agricultural interests of different parts of the district are briefly discussed. The region considered comprises that portion of the Great Plains bordering the Rocky Mountain Front Range, which extends from about longitude 110° W. to about 112° 30' W., and from about lati- tude 47° N. to about 48° N". It includes the lowlands lying between the Little Belt and Highwood mountains, and extends to the west and north with increasing width to a point about 10 miles north of Teton River. The area comprises about 3,600 square miles, the location of which is shown in the key map in PL I (pocket). It is situated in north-central Montana, mainly in Cascade and Teton counties, but includes portions of Fergus, Chouteau, and Lewis and Clark counties. It is bounded on the south and west by the Little Belt, Big Belt, and Lewis mountain ranges, and on the east and north by the Great Plains and Highwood Mountains. The topographic map used as a base for the geologic map, and also for the water-resources and other maps presented in the report, was, for the eastern part of the district, taken mainly from detailed reconnaissance surveys of the Great Falls coal field, made from a land-subdivision standpoint by the author and his party. Topo- graphic data for the marginal portions of the east half of the map 8 GEOLOGY AND WATEKS OP GREAT PALLS REGION, MONT. were also taken from atlas sheets of the Fort Benton and Great Falls quadrangles surveyed in 1896. The map of the western portion of the field was made in greater part from rapid reconnaissance surveys carried on while the underground-water investigation was being made. Throughout the work valuable assistance was rendered by W. R. Calvert and D. E. Winchester. These gentlemen mapped portions of the area, collected much of the well and spring data, and made field assays of the water. In the areal geologic mapping assistance was given by H. M. Eakin, who measured numerous sections and col- lected structural data. Much valuable information was furnished by S. B. Robbins, engineer of the Sun River reclamation project, regarding both underground and surface waters of the Great Falls region, and aid was also given by O. C. Mortson and John French. LITERATURE. GENERAL STATEMENTS. Previous observers have given but little information regarding the underground water resources of the Great Falls region. The surface waters, particularly the Great Falls of Missouri River and the Giant Springs, are phenomena that have attracted widespread attention since the earliest explorers followed up the course of Missouri River to the westward. Captain Lewis, of the Lewis and Clark expedi- tion, who visited this region in 1804, was the first to give an accurate account of the Great Falls and Giant Springs, and doubtless other early explorers had been attracted by them and made brief mention of their occurrence in describing the Northwest Territory. The work of the geologists of the Hayden and transcontinental surveys was con- fined mainly to the region lying east of Great Falls, and with one or two exceptions did not extend into this district. With the develop- ment of water power at the Black Eagle Falls, which took place in 1893, a number of articles appeared in the engineering journals de- scribing the power which could be generated in this vicinity by the development of all the large waterfalls. In the Fort Benton folio^ published in 1899, which includes a portion of the Little Belt Moun- tains, the Highwood Mountains, and adjoining plains, attention is called to the favorable prospects for artesian water in a portion of the quadrangle. Since the Government irrigation project has been undertaken in Sun and Teton River valleys, a number of scientific and popular articles have been published dealing principally with the surface waters of the region. Following is a chronological list of the more important papers published on the surface-water resources of the Great Falls region, one of which sets forth the prospects for artesian water in the eastern part of the district. LITERATURE. 9 BIBLIOGRAPHY OF THE MORE IMPORTANT PAPERS RELATING TO THE WATER RESOURCES OF THE GREAT FALLS REGION, MON- TANA. Lewis and Clark Expedition, 1804-6. (Coues, 4 vols., 1893.) An account of the journey up the Missouri from St. Louis to the Rocky Mountains, thence to the Pacific coast. Contains description of the region bordering on the Missouri in the vicinity of Great Falls, Mont. The falls of the Missouri were measured and described. Newberry, J. S. Surface geology of the country bordering the Northern Pacific Railroad. In Am. Jour. Sci., vol. 30, pp. 337-347. 1885. Includes a brief description of the surface geology in the vicinity of Great Falls, Mont., with special reference to glacial drift. Newell, F. H. Thirteenth Annual Report U. S. Geological Survey, pt. 3. 1892. The proposed irrigation system of the Sun River valley and the adjacent region is fully described, pp. 371-386, and the rainfall, topography, and amount of reclaimable land are discussed. Nettleton, B. S. Artesian and underflow investigation : Senate Ex. Doc. 41, pt. 2, 52d Cong., 1st sess., pp-78. 1892. Discusses the surface and underground water of Great Falls district in con- nection with an explanation of the source of artesian water in eastern South Dakota. Parker, M. S. Water power of the falls of the Missouri, Great Falls, Mont. In Engineering News, vol. 32, p. 44. 1894. The several falls of the Missouri are described, and estimates are made of available power. Reference is made to the Giant Springs. Parker, M. S. The Great Falls water power. In Engineering Record, vol. 31, No. 16, pp. 274-275. 1895. Gives brief description of the various falls of the Missouri at Great Falls, Mont., and detailed illustrations of the power plant at Black Eagle Falls. Weed, W. H. Fort Benton folio, Montana. Geologic Atlas, U. S., folio No. 55, U. S. Geol. Survey. 1899. Discusses the general geology and mineral resources of the region, also the probability of obtaining artesian water in the area east of Otter Creek. Willis, Bailey. Stratigraphy and structure, Lewis and Livingstone ranges, Montana. In Geol. Soc. America, vol. 13, pp. 305-352. 1902. Describes the physiography of the Lewis and Livingstone mountain ranges and adjoining plains, also character and structural relations of the Algonkian, Carboniferous, Cretaceous, and Quaternary rocks. Newell, F. H, Second Annual Report of the Reclamation Service. 1904. An abstract of a reconnaissance in Sun River valley, Montana, is included. Newell, F. H. Third Annual Report of the Reclamation Service. 1905. The proposed irrigation project of the Sun and Teton rivers district is dis- cussed. The water supply of the streams, the storage reservoirs available, and the territory subject to irrigation are described. Upham, Warren. Outer glacial drift. In Am. Geologist, vol. 34, pp. 151-160. 1904. The glacial drift of the Northwestern States, including Montana, is discussed. Reference is made to its effect upon the drainage of the Missouri River system. Leiberg, J. C. Forest conditions in the Little Belt Mountains Forest Reserve, Montana, and the Little Belt Mountains quadrangle. Prof. Paper No. 30, U. S. Geol. Survey. 1904. a Compiled by W. R. Calvert. 10 GEOLOGY AND WATEKS OF GKEAT FALLS REGION, MONT. The surface waters of the region and their relation to agricultural, grazing, and forest lands, are included in the discussion. Calhoun, F. H. The Montana lobe of the Keewatin ice sheet. Prof. Paper No. 50, IT. S. Geol. Survey. 1906. The glacial history of the Great Falls region is given, with a discussion of the effect of glaciation on the drainage system of the Missouri in that area. Reference is made to artesian conditions near Chouteau. GEOGRAPHY. GENERAL FEATURES. The area treated in this report presents a variety of surface features. It lies in a region which is transitional between plain and mountainous topography and includes portions characteristic of both. Its salient features are broad, gently sloping plateaus bordering the adjacent mountain ranges. These plateaus are traversed by numerous mountain streams, which flow through deep and relatively narrow valleys throughout the eastern portion of the district, but toward the west, where the valleys have been developed in softer rocks, they are usually wide and open. Along the southern margin of the area, from Smith River to the eastern end, the surface of the plains rises grad- ually by sloping plateaus, culminating in a zone of high, hilly coun- try bordering the Little Belt Mountains, which lie farther to the. south. East of Belt Creek and north of the area described the High- wood Mountains rise abruptly above the plains as a cluster of high isolated peaks, reaching an altitude of over 7,000 feet. Between the Highwood and Little Belt mountains is the Otter Creek divide, having at its lowest point an altitude of 4,300 feet. To the east of this divide the country is drained by Arrow Creek and its tributaries and to the west by Belt Creek and its most important branch, Otter Creek, from which the above- described divide derives its name. PLAINS PROVINCE. Thoughout the region which lies to the west of Missouri River the country presents topographic features characteristic of the Great Plains, of which it forms the western margin. It is a region of long, gently sloping plateaus traversed by streams having relatively wide valleys. On the summit of this table-land at many places remnants of higher plateaus occur in the form of isolated buttes or long irregu- lar ridges, of which Teton Ridge forms a notable example. West- ward the surface rises by successive plateaus toward the base of the Lewis Mountains ; the surface features become more diversified ; and there are a number of high isolated buttes south of Sun River which form some of the most conspicuous topographic features of the region. There is a moderate range of altitude in the district. The highest points examined occur along the base of the Little Belt GEOGEAPHY. 11 Mountains, where the more prominent summits rise to an altitude of over 5,000 feet. The lowest point in the district is along Missouri River below Big Falls, where the altitude is 2,900 feet above sea level. The average altitude of the region is between 3,500 and 4,000 feet. The greatest variation in altitude for any locality is about 1,300 feet in a horizontal distance of 1^ miles. This occurs between Belt Creek and the summit of Belt Butte at the town of Belt. In the Plains province the relative altitudes of the summits of the plateaus border- ing the valley bottoms range from 300 to 600 feet. DRAINAGE. The Great Falls region is drained by Missouri River, which crosses its central portion flowing in a northeasterly direction. Its flow varies greatly at different seasons of the year. High water occurs in the late spring and early summer months, when the greatest amount of snow is melted in the mountains, and the low-water mark is usu- ally reached in the month of September. The principal tributary of Missouri River from the north is Sun River, which rises in the Lewis Mountains and, flowing eastward, joins the Missouri at Great Falls. From the south the most important tributaries are Smith River and Belt Creek, the former entering the Missouri about 7 miles above Great Falls and the latter 10 miles below, outside of the area to which this report relates. Smith River drains an extensive country lying between Big Belt and Little Belt mountains, and Belt Creek drains the northern slope of the Little Belt Range (PL II, A). Teton River crosses the northern part of the area, flowing in an easterly direction. Its principal tributaries are Deep and Muddy creeks, both of which carry considerable water. Throughout the Plains province many of the smaller streams are intermittent, but those draining the north- ern slope of the Little Belt Mountains always have more or less water, especially in their upper courses. DETAILED DESCRIPTIONS OF DISTRICTS. East of the low divide between the Highwood and Little Belt mountains the country slopes gradually northeastward toward Mis- souri River. It is traversed by several streams draining the slopes of the adjoining mountains. These streams flow through relatively wide valleys that are bordered by gravel-capped terraces of differ- ent elevations. Stanford Buttes, a prominent ridge lying between Running Wolf and Surprise creeks, is flat topped, being a remnant of an ancient terrace. To the north and east of this ridge gravel-capped plateaus of lower levels occupy interstream spaces. Toward the Lit- tle Belt Mountains the gravel-capped terraces give way to prominent hog-back ridges formed by the sandstone members of the Ellis and 12 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. Kootenai formations, which extend in an irregular line of outcrop along the base of the mountains. Skull Butte, a low dome-shaped uplift situated about 6 miles south of Stanford, rises about 200 feet above the surrounding region. South of Skull Butte there are a num- ber of prominent ridges with long gradual slopes to the north and bold escarpments to the south, which overlook valleys excavated in the soft Quadrant shale. In the southwest corner of T. 16 N, R. 10 E., is located Wolf Butte, a very prominent topographic feature in this part of the area. Broadly viewed, the district lying between the Otter Creek divide and Missouri River is a high plateau sloping northward and deeply dissected by numerous canyons. Belt and Box Elder creeks, Sand Coulee, and Smith River are the principal streams traversing this region. They all flow through deep, narrow valleys. The altitude of the plateau varies from 3,500 feet along Missouri River to 4,500 feet or more along the southern border of the field. The difference in altitude between valley bottom and plateau summit in the northern part of the area is 300 to 400 feet, but toward the mountains this difference increases to over 600 feet. The streams of this district all flow in a northerly direction, except three of the larger tribu- taries of Smith River — Boston, Ming, and Goodwin coulees — which flow nearly west. Sand Coulee, which is formed by the confluence of a number of canyon tributaries southeast of Stockett, Aoavs north- ward for about 10 miles, then turns sharply to the west, and for the remainder of its course meanders through a wide, flat-bottomed valley formed by preglacial erosion of Missouri River. West of the Missouri and south of Sun River the surface rises westward in successive plateaus. The lowest of these plateaus, which lies north of Ulm station and comprises what is locally known as Ulm Bench, has an altitude of about 3,650 feet. West of Ulm Bench is a low saddle separating it from a higher plateau, which in its western extension is surmounted by two isolated buttes forming two of the most conspicuous topographic features of the Plains province. Square Butte, the smaller of the two, is a flat-topped, rectangular- shaped butte, rising abruptly to a height of 500 feet above the sur- rounding plain (PI. II, B). Fort Shaw Butte, which is in reality a ridge trending northwest, is of equal prominence, but has less pre- cipitous sides. It is less than 1 mile wide, is 2^ miles long, and is located about 2 miles west of Square Butte and almost directly south of Fort Shaw. It has an altitude of about 4,500 feet, rising several hundred feet above the surrounding country. About 3 miles south- west of Shaw Butte is a third, known as Crown Butte, which is also very prominent but somewhat smaller than the two above described. Between Shaw and Crown buttes there is a wide, open valley drained by Little Muddy Creek, a large intermittent stream joining the Mis- U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 221 PL. II A. DRY BED OF BELT CREEK, NEAR BELT, MONT. B. NORTHWEST SIDE OF SQUARE BUTTE, SHOWING EAGLE SANDSTONE OVERLAIN BY IGNEOUS ROCK. GEOGKAPHY. 18 souri near Riverdale. South of Little Muddy Creek the surface rises rapidly toward the mountains. Between Sun River and Sims Creek a high gravel-capped plateau of irregular outline occurs, which extends 6 to 7 miles westward. It has an altitude of 3,600 feet and is bordered on the south by the wide, open valleys of Sims Creek and its tributaries. To the west the region consists of prominent ridges and detached buttes, presenting bold escarpments to the north over- looking Sun River valley and long gradual slopes to the south. Between Sun and Teton River valleys there is a high, gravel- capped, sloping plateau, which continues from the western margin of the district in a more or less modified form to Muddy Creek of Sun River. The southern edge of this plateau is very irregular from the west boundary of the district to a point about 3 miles north of Lowry, but from this point eastward it becomes sharply defined by a line of bluffs about 200 feet high. In its western ex- tension this plateau increases in altitude and culminates in a high crescent-shaped ridge with a bold north- facing escarpment over- looking Deep Creek valley. Eastward the ridge terminates in a number of isolated hills, the larger of which are locally known as Priest Buttes. From Priest Buttes southward to Freezeout Lake the east face of the plateau is deeply serrated by numerous canyons. Bordering this plateau on the east is a belt of level country, imper- fectly drained, which is locally known as Freezeout Basin. Near the middle of this basin and at the base of Freezeout Butte is Freeze- out Lake, 1J miles wide and about 3 miles long, which contains water only a small portion of the year. East of Freezeout Basin the sur- face rises slightly to a level table-land or plateau, which is locally known as the Freezeout Bench. The elevation of this plateau varies from 3,900 to 4,000 feet. The area between Teton River and its principal tributary from the north, Muddy Creek, is in its central portion a level plateau or bench having an altitude of 3,900 feet. It is locally known as Burton Bench. On the east, where this plateau is crossed by the terminal moraine of the Keewatin ice sheet, its surface is hilly, such as is characteristic of a morainal district, but to the west the surface rises gradually toward the base of the high bluffs occurring on either side of Ralston Gap. West of this prominent line of bluffs the country, which is crossed in its northern part by Muddy Creek, is rolling. North of Muddy Creek there is a low line of bluffs 100 to 200 feet high, the margin of which is included within the area de- scribed. Between Teton River and its most important tributary, Deep Creek, is an area containing in its central portion typical bad- lands topography, with long, irregular ridges culminating in sharp peaks, the most prominent of which are Teton Buttes. On the north 14 GEOLOGY AND WATEKS OF GREAT FALLS REGION, MONT. side of this high ridge the surface slopes away to Teton River, while to the south there is a wide, gravel-capped terrace which borders Deep Creek on the north. GEOIiOGY." STRATIGRAPHY. GENERAL OUTLINE. The formations occurring at the surface throughout the area to which this report relates consist mainly of sedimentary rocks with igneous intrusions in the form of dikes or laccoliths. The latter occur especially in the regions bordering the adjacent mountain ranges. The strata in general lie nearly horizontal or dip at a rela- tively small angle to the northeast away from the mountains. They are representative of Carboniferous, Jurassic, Cretaceous, Tertiary, and Quaternary systems. The distribution of these formations, except the Tertiary and certain members of the Quaternary, is shown on the geologic map (PL I), and their structural relations, particularly those affecting the occurrence of underground water, are illustrated in the cross sections. The table on pages 15-16 sets forth the order, age, characteristic features, thickness, and water capacity of the formations. a A detailed report of the geology of the Great Falls region will appear in Bulletin No. 356 of the Geological Survey. 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MADISON LIMESTONE. The Madison limestone is very conspicuous, bordering the north side of the Little Belt Mountains, but in the greater part it lies out- side of the area here described. The only exposures in the district are found along East Fork of Sand Coulee and its tributaries, where a local doming of the beds exposes about 100 feet of the formation. The distribution of the limestone is shown on the geologic map (PL I). Along the flanks of the Little Belt Mountains, outside of the area to which this report relates, the limestone has a thickness of about 1,000 feet, and three members have been recognized by pre- vious workers. The lower member, which is more or less argilla- ceous, has been called the Paine shale, the more massive limestone of the middle part of the formation the Woodhurst limestone, and the top member the Castle limestone. The Castle limestone forms the " sluicebox canyon," the lower end of which is at Riceville. It is a part of the upper division of Madison limestone, which is exposed at numerous places in the vicinity of Stockett. That portion of the formation exposed in the area here described consists mainly of limestone, interbedded with calcareous clay. The limestone is usually massive and compact, and is of medium to dark gray color, weathering light. It occurs in beds 10 to 12 feet thick, and is generally relatively pure. At Stockett, 15 feet of oolitic limestone was observed, and at another locality on Ming Coulee, where about 110 feet of the limestone was exposed, the lowest mem- ber contains bands of dark-colored chert. Fossils were collected from the limestone at Stockett, also on the head of Ming Coulee, outside the area described. These fossils have been examined by Dr. G. H. Girty, who regards them as of Mississippian age. In the Little Belt Mountains the Madison limestone is said to carry a typical Mississippian fauna. The Madison limestone is believed not to be water-bearing, espe- cially that portion which outcrops within this area. Several wells have penetrated the limestone in the vicinity of Stockett and Sand Coulee, and have invariably failed to obtain water. QUADRANT FORMATION. The Quadrant formation consists of sandstone, shale, and limestone, with beds of gypsum in the lower part. It lies outside of the area studied except in a few localities, notably on Belt Creek, near Rice- ville, on Little Otter Creek, 2J miles above its mouth, along the base of the Little Belt Mountains from Otter Creek to near the southeast corner of the area described, and in the central part of Skull Butte. 54572— irr 22i—09 2 18 GEOLOGY AND WATEKS OF GEEAT FALLS REGION, MONT. In the exposure near Riceville, the basal member of the Quadrant con- sists of reddish sandy shale with an occasional layer of gypsum. Overlying this member, to which Weed a has applied the term Kibbey sandstone, the deposits consist largely of shale with interbedded limestone and some sandstone, designated the Otter shale by the same author. The total thickness of the formation as exposed near Rice- ville is less than 500 feet. The formation is not important as a water bearer, for throughout the greater part of the district it lies too deep to be reached by ordi- nary well borings, and as the upper member is shale and limestone and the lower gypsum-bearing soft sandstone, it is highly probable that if water were obtained it would be considerably mineralized. In the vicinity of Wolf Butte a number of sulphur springs issue from the shale members of this formation, and wherever springs are found in it the water contains a large amount of objectionable salts. JURASSIC SYSTEM. ELLIS FORMATION. The Ellis formation is composed of a basal limestone of variable thickness ranging from 20 to 60 feet, above which lies a coarse con- glomerate that passes upward into a medium-grained sandstone, light brown in color and more or less thin bedded. The limestone and con- glomerate contain Jurassic fossils. Those in the conglomerate are sometimes fragmentary, but more often combined with pebbles of limestone and quartzite several inches in diameter. The component parts of the conglomerate are bound together by a calcareous cement. The total thickness of the formation is about 125 feet, and it rests un- conformable upon the Quadrant and Madison formations. Though no practical tests have been made of the water capacity of the forma- tion, it is probable that the sandstone of the upper part would readily absorb water under favorable conditions. MORRISON FORMATION. The Morrison formation, which is extensively exposed along the Rocky Mountain Front Range in southern Montana and Wyoming, is also believed to occur along the northern base of the Little Belt Moun- tains. In previous investigations in this field the Morrison formation has not been recognized, and the beds comprising it have been in- cluded in the " Cascade " formation. During the field season of 1906 dinosaur bones, believed by C. H. Gilmore to be of Jurassic age, were found at one horizon in many different localities, and at one exposure, Weed, W. H., Geologic Atlas U. S., folio 55, U. S. Geol. Survey, 1899, p. 2. GEOLOGY. 19 about 30 feet below the bone-bearing horizon, a green shale was seen containing a distinctly fresh-water fauna later than the Ellis forma- tion. These sediments, which are here provisionally regarded as con- stituting the Morrison formation, consist of sandstone and bright- colored sandy shale, with an occasional layer of impure limestone, generally in lenticular form. It lies with apparent conformity on the Ellis, and is overlain conformably by the Kootenai. The thickness varies from 60 to 120 feet, but the exact limits of the formation are often difficult to determine. Fragments of bones have been found at different horizons throughout the overlying Kootenai formation, but thus far none have been discovered in this region sufficiently well pre- served for specific determination. It is possible that future investi- gation may prove that the sediments here tentatively regarded as be- longing to the Morrison formation are in reality a basal member of the Kootenai. The formation is generally exposed in a narrow band on the inner rim of a low ridge formed by the harder overlying rocks of the Koo- tenai formation. It outcrops all along the base of the Little Belt Mountains from the east end of the district to Smith River. Good exposures occur along the upper courses of Sage, Skull, Running Wolf, Hazlett, Surprise, Geyser, and Otter creeks, and in the bluffs for some distance back from the mountains along Belt Creek, Sand Coulee, Smith River and its principal tributary, Ming Coulee. The following section will show the succession of the beds : Section of the Morrison formation on the east side of Belt Creek, Montana, in NE. i sec. 30, T. 18 N., R. 7 E. Feet. Gray, thin-bedded sandstone 17 Pebbly conglomerate occurring in lenses 5 Maroon and green shale 52 Green shale capped by 1£ feet of gray sandstone 5 Calcareous sandstone, weathering light brown 5 Green shale , 20 Massive sandstone, weathering light brown 7 Dark-green shale containing thin limestone layers 9 Ellis formation. 120 The so-called Morrison formation is believed not to be an impor- tant water-bearing formation in this general district. It is composed largely of shale and clay, which are apparently not sufficiently porous to absorb or transmit underground water freely. It is possible, how- ever, that some of its sandy members may contain water ; but it is in- ferred from their lithologic character and the absence of springs throughout their exposed areas that they are not water bearing. 20 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. CRETACEOUS SYSTEM. KOOTENAI FORMATION. The Kootenai formation includes the upper third of the " Cas- cade," the Dakota, and the basal red shale included in the Colorado formation as described by W. H. Weed a in the Fort Benton folio. The name Cascade, as referring to a Cretaceous formation, was first used by that author in his description of the rocks of the Fort Benton quadrangle to apply to a series of beds ranging in thickness from 225 to 500 feet. The lower part of the formation, as originally de- scribed, consisted of lavender-tinted sandstone and highly colored shale and clay with massive gray sandstone above containing at its base a workable bed of coal. During the present investigation, as previously stated, saurian bones, believed by some geologists to be of Jurassic age, were dis- covered in the lower half of the so-called " Cascade " formation, which indicates that these beds are probably of Morrison age, although vertebrate remains continue to occur to the top of the Kootenai. Between a horizon 45 feet below the coal bed and the top of the " Cascade " formation, as above defined, fossil plants of Kootenai age were collected at four different horizons, which estab- lishes the lower Cretaceous age of this portion of the formation. On the east side of Spanish Coulee, a tributary of Smith Kiver, at a horizon about 150 feet above the " Cascade " formation, in beds the stratigraphic equivalent of which near Belt are regarded provisionally by Weed as of Dakota age, a large collection of Kootenai plants were secured from dark coaly shale associated with red and green shale and clay. Overlying this plant-bearing bed there is about 200 feet of sediment consisting of red shale and sand- stone, not differing materially in stratigraphy from beds imme- diately underlying the plant horizon. For this reason, together with the apparent absence of the Dakota flora in these beds, this member is provisionally regarded as of lower Cretaceous age and included in the Kootenai formation. It is overlain by dark-colored shale and sandstone of the Colorado formation, in the lower part of which were discovered marine saurian remains. In this report it is not regarded as advisable to employ the name Cascade for the following reasons : The term has not been as exten- sively used in the literature as the older term Kootenai; its usage would necessitate redefining the term in order to separate its lower member, which is now believed to be Morrison ; and the beds imme- diately overlying the formation can not be differentiated paleonto- logically from the " Cascade," both being of lower Cretaceous age, a Weed, W. H., Geologic Atlas U. S., folio 55, U. S. Geol. Survey, 1899. GEOLOGY. 21 rendering it necessary to base the upper limit of the formation in question purely on lithologic grounds. The Kootenai formation is about 450 feet thick and consists of alternating layers of sandstone and shale with the former predomi- nating, especially in the lower half. The sandstone varies in thick- ness from 10 to 80 feet and is more or less massive in character. In the upper part shale predominates and is interbedded with thin layers of impure sandstone. At Belt, on the east side of Belt Creek, where a complete section was measured, the basal member of the formation consists of a sandy shale interbedded with sandstone, the latter pre- dominating, and the whole having a thickness of about 60 feet. This member sometimes consists of firm, massive sandstone, with only a small percentage of shale. It is overlain by coal, which here has a thickness of 6 feet, including a few thin partings. Above the coal there is a dark, coaly shale 5 to 6 feet thick, covered by 38 feet of massive light-gray sandstone. This sandstone is followed in ascend- ing order by 138 feet of beds consisting mainly of alternating layers of sandstone, red shale, and clay, with an occasional limestone lens in the lower part. Above this alternating series of sandstone, red shale, and limestone there is about 200 feet of red shale, which con- stitutes the topmost member of the formation. On the north side of Skull Butte the base of the Kootenai consists of a soft, light-gray, massive sandstone, but in other respects the portion of the formation exposed in this locality agrees closely with the beds exhibited at Belt Butte. A section of the Kootenai on the north side of Skull Butte is given below: Section of the Kootenai formation on the north side of Skull Butte, Mont. Reddish sandy shale. Feet. Gray thin-bedded sandstone 1J Reddish sandy shale with layers of sandstone in the lower part 21 Greenish-gray sandstone, weathering dark, thin-bedded above, clay-ball conglomerate below 4 Reddish sandy shale, with layers of sandstone in lower part__ 27 Gray cross-bedded sandstone, clay-ball conglomerate in lower part 5£ Reddish sandy shale 30 Soft, thin-bedded sandstone , 20 Gray, massive sandstone, clay-ball conglomerate Si Red sandy shale 38 Gray, massive sandstone, clay-ball conglomerate 5 Red sandy shale 24 Calcareous sandstone, alternating with sandy shale 20 Light and dark gray, fine-grained, massive sandstone 86 _ Coal and coaly shale (estimated) 6 Soft, massive, gray sandstone 62 353i 22 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. Next to the Colorado the Kootenai has the greatest areal distribu- tion of all the formations outcropping within the area. It occupies the surface over a great part of the district lying between Smith River and Belt Creek and is the surface formation of the high plateaus south of Otter Creek. Beyond Otter Creek it is exposed as a band of varying width, which narrows eastward. The Kootenai is the principal water-bearing formation of the Great Falls region. As above stated, it consists mainly of sandstone and sandy shale. The sandstone is medium to coarse-grained and porous so that it readily absorbs water when the structural conditions are favorable. Along each side of Otter Creek and its tributaries from the south, also in Sand Coulee and its tributaries, the various sand- stone members of the Kootenai formation are the source of numer- ous springs, and in the eastern part of the territory, where this sand- stone is overlain by impervious Colorado shale, it contains artesian water. COLORADO FORMATION. The Colorado formation is well developed in this general region, being represented by about 1,600 feet of beds. In its type locality in the vicinity of Fort Benton, only a few miles to the north, it is essentially a shale formation, but throughout this region the lower part contains a number of prominent sandstone members. West of Great Falls, where the formation is typically developed, its basal member consists of a soft, massive sandstone somewhat concretionary, which is about 30 feet thick. Above this sandstone there is approxi- mately 35 feet of sediment composed largely of dark-colored shale, with a few sandstone beds. This dark-colored shale is overlain by gray, coarse-grained, massive sandstone, containing concretionary layers and an occasional thin bed of soft, sandy shale, the whole having a thickness of about 80 feet. Above the sandstone for about 300 feet the beds consist mainly of alternating layers of sandstone and shale. These are followed by 700 feet of beds composed largely of uniformly dark-colored shale, which constitutes the uppermost member of the Colorado. The Colorado formation is exposed throughout a wide area extend- ing along the south side of the Highwood Mountains from Belt Creek southeastward to the east border of the district. Its basal sandstone members occupy the summit of Red Buttes and continue westward as a plateau capping to the Missouri River valley. Smith River and its tributaries cut the basal sandstone of the Colorado, exposing the underlying Kootenai rocks. The Colorado formation occupies the surface of the highland lying between Missouri and Sun rivers, also north and west of these streams to beyond the Teton. Its areal distribution is larger than any other formation within the district. GEOLOGY. 23 The shale of the Colorado formation, which constitutes nearly two- thirds of its entire thickness, is not water bearing, but the sandstone comprising its basal portion, which is medium to coarse grained and porous, carries an abundance of water. Throughout Ulm Bench, which is capped by basal Colorado sandstone, a number of wells have been sunk that furnish a large supply of excellent water derived from this formation. It is also the source of well-water supply on the high- lands between Smith and Missouri rivers. East of Smith River there are a number of small springs situated along the margin of the detached plateaus which issue from the base of the Colorado sand- stone. A typical spring of this character is shown in PL V, A. M0NTAN1 GROUP. The Montana is extensively developed in the western part of the Great Falls region. It is represented within the area examined b}^ the Eagle and Claggett formations. West of the district fossils were obtained from it which are believed to be of Judith River age. No Pierre shale was recognized in this general vicinity, although the formation is probably represented in the steeply dipping beds that skirt the base of the Lewis Mountains. While no careful examination was made of the Cretaceous formations bordering the base of the Lewis Mountains, it is believed that the various members that constitute the Montana group in the Judith River basin are here represented. EAGLE SANDSTONE. The Eagle sandstone consists of massive gray sandstone containing large iron-stained concretions 3 to 10 feet in diameter, which are fossiliferous. Sandstone layers alternate with sandy shale in the lower part. It has a thickness of about 90 feet and is exposed in places underneath the igneous rock capping Square, Fort Shaw, and Crown buttes (see PI. II, B). It occupies, the summits of the bluffs at Lowry where fossils characteristic of the formation were collected. Farther north it caps Freezeout and Priest buttes and gives rise to a conspicuous line of bluffs extending northward west of Chouteau and past Ralston Gap to the northern margin of the district. The distribution of the formation is not shown on the geologic map. The Eagle sandstone is a water-bearing formation, as is shown by the numerous small springs which issue from its base around Fort Shaw and Square buttes. CLAGGETT FORMATION. Overlying the Eagle sandstone is the Claggett formation, which consists of dull green and gray sandy shale, clay, and impure sand- stone; also massive, light-gray and very dark-green, iron-stained, 24 GEOLOGY AND WATERS OF GEEAT FALLS REGION, MONT. conglomeratic sandstone. In the upper part of that portion of the formation exposed in the area examined there is an erosional uncon- formity, which may be local, exhibiting a marked change in the char- acter of the beds immediately above and below the contact. This apparent unconformity is well exposed on the north face of a high bluff on the south side of Sun River about 7 miles below Augusta, where the following section was taken : Section of a portion of the Claggett formation on the south side of Sun River, Mont. a Feet. Sandstone, dark green, conglomeratic, interbedded with sandy, leaf-bearing shale 50 Unconformity? Sandstone, massive, gray, and sandy shale, fossiliferous throughout 125 Sandstone, soft greenish gray 95 Shale, sandy and dark green, interbedded with sandstone layers which are concretionary 100 The Claggett formation occupies the surface south of Sun River and west of Crown Butte, also north of Sun River throughout a part of the district lying west of a line connecting Lowry with Bas Chris- tian's ranch. The areal distribution of the formation is not shown on the geologic map. The sandstone members of the Claggett forma- tion probably contain more or less water, although as far as could be ascertained no wells have been sunk in them. QUATERNARY SYSTEM. TERRACE DEPOSITS. Throughout a great part of the territory lying east of Otter Creek divide and north of Sun River most of the interstream spaces are capped by bench gravel. This deposit consists of gravel and sand ranging in thickness from 10 to 40 feet and having smooth surfaces sloping gently away from the uplift. The component parts of the gravel, especially in the terraces north of Sun River which have their source to the west in the Lewis Mountains, are mainly sand- stone, limestone, and chert, with a small per cent of igneous rock, the whole being sometimes bound together by calcareous cement. In the eastern part of the area the gravel of the terraces is more di- versified, containing a larger percentage of igneous rock derived from the Little Belt Mountains to the south. a Fossils collected from the locality where the above section was measured are regarded by T. W. Stanton as of the same age as forms collected from the Claggett formation in Judith River basin. GEOLOGY. 25 Gravel deposits of four different periods have been recognized. The earlier gravel, which is often cemented into conglomerate, occurs only in limited areas, capping some of the more prominent buttes and ridges, while the later is widely distributed, especially through- out the eastern part of the field. This bench gravel probably ranges in age from Tertiary to later Quaternary age, having been brought down by streams from the Little Belt Mountains and spread by them over the lower plain country as their courses were shifted from time to time. The distribution of the terrace deposits is not shown on the geologic map. The gravel terraces of the Great Falls district usually contain some water. The amount, however, is not large, and a well sunk in them rarely obtains a sufficient quantity for both stock and domes- tic purposes of an average-sized ranch. That these gravels contain water, however, is shown by the fact that wherever they occupy ex- tensive areas they are the source of numerous small marginal springs. The water contained in them is derived from rainfall. GLACIAL DEPOSITS. Glacial deposits of late Wisconsin age occupy a considerable area throughout the Great Falls region. The terminal moraine of the Keewatin ice sheet enters the district at the east end of Burton Bench, extending south to Teton River, where it turns to the east and follows along the northern side of Teton Ridge to the vicinity of Duttcn. From here it extends diagonally southeastward past Benton Lake, across Missouri River to Sand Coulee near Gerber station, where it makes a sharp bend eastward and continues thus past the head of Red Coulee, thence northeastward to Belt Creek, where it passes off the northeast margin of the area. Its location and extent, as worked out by Calhoun, a are shown on the geologic map. The Keewatin ice sheet, extending into the region from the northeast, dammed up Mis- souri River and its tributaries, forcing the former to abandon its channel in many places, some of which were not reoccupied on the retreat of the ice. The abandoned channel, a portion of which is shown on the accompanying map, extends from the mouth of Sand Coulee, 4 miles south of Great Falls, northeastward in meandering course to the mouth of Belt Creek, where it unites with the present Missouri. In addition to the morainal deposits described above, there was deposited during the occupation of this general region by the ice extensive lake sediments in front of the terminal moraine. Much of this material has been removed by post glacial erosion on the higher lands, a Calhoun, F. IT. H., Montana lobe of the Keewatin ice sheet : Prof. Paper U. S. Geol. Survey No. 50, 1906. 26 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. but all the larger valleys in front of the moraine are filled with these sediments. Lake deposits of two different periods have been recog- nized by glaciologists in this region — an earlier and a later deposit. The limits of the earlier lake sediments can be ascertained only by bowlders lodged on the summits of the plateaus, while much of the deposits of the more recent lake still remains as a filling in the larger valleys. The distribution of the lake sediments is not shown sepa- rately, but is included with the valley wash. The glacial deposits — especially the more recent lake sediments fill- ing the valleys — are water bearing, and in some places in front of the terminal moraine they are the source of artesian water. The artesian water of Burton Bench is derived from granitic gravels overlain by impervious glacial clays deposited in front of the terminal moraine, and in Box Elder Creek valley is a flowing well, which is believed to have a similar source. ALLUVIUM. The alluvial deposits of this general region exhibit the usual di- versified character, especially along the larger streams, such as Mis- souri, Sun, and Teton rivers, the deposits varying in width from one-fourth to 1 mile. The material is composed of fine silt, sand, clay, and gravel, which have been transported by streams in times of high water and deposited at different places along their courses. Along Missouri River from the base of the Big Belt Mountains northeastward to the vicinity of Great Falls the river flows in a meandering course through a wide plateau plain of alluvium, but east of that point it flows through a narrow canyon in which only small detached areas of alluvium are found. The alluvial deposits generally contain a large amount of water and are the source of well water along nearly all the valleys in this region. The water in this formation is generally relatively pure, although the alluvium of some of the smaller valleys, especially in the Colorado shale areas, contains highly mineralized water. STRUCTURE. As the movement of water underground is governed to a certain extent by the structure of the formations, a brief description of the structural relations of the rocks of different parts of the district is here given, attention being called to the manner in which these structures affect the prospects for artesian water. Throughout the Plains portion of the region described the structure is relatively simple and the rocks lie nearly horizontal, dipping with a small angle to the north and east away from the mountains ; but in the mountain- ous portion the structure is more complex. GEOLOGY. 27 LITTLE BELT MOUNTAINS. The general structure of the Little Belt Mountains, which border this area on the south, is that of an anticlinal uplift with sharply dipping sides and a flat summit. In the central portion of the range the stratified rocks lie nearly horizontal, while along the northern flanks of the uplift, as shown on the head of Avoca Creek, the lime- stone dips at an angle of 15° to 20° toward the lower Plains country. The simple structure of the northern part of the uplift has been considerably modified by the intrusion of igneous rocks in the form of laccoliths, which have caused local doming of the strata in many places. Only one of these laccolithic domes occurs within the area described, but there are others, such as are found east of Kibbey and in the head of Dry Wolf Creek, whose marginal structure ex- tends into this area. In the vicinity of the larger intruded masses of igneous rock the dips are often steep and variable, but in that portion of the mountain front where local intrusions have not dis- turbed the strata they dip away normally from the uplift at angles of 6° to 12°, lessening gradually toward the lower Plains country, thus producing ideal structural conditions for the occurrence of artesian water on the plains. HIGHWOOD MOUNTAINS. The Highwood Mountains, which border on the north the eastern end of the area described, are structurally different from the Little Belt Range. They consist of a group of isolated peaks which have been formed by igneous intrusion in Cretaceous rocks which were horizontally bedded or slightly inclined eastward. Subsequent to this intrusion stream erosion has removed much of the softer rock, leaving the harder rock standing as a cluster of peaks above the surrounding plain. LEWIS AND BIG BELT RANGES The Lewis and Big Belt ranges, being more remote from the field investigated, were not examined, but their broader structural features, as worked out by previous investigators, are given below. The Lewis Mountains, lying to the west of the district and consti- tuting the Rocky Mountain Front Range of northern Montana, have been formed by an overthrust fault of considerable magnitude, ex- tending along the east side of the range, which superimposes Algon- kian strata on upper Cretaceous rocks. The extent of the thrust in the vicinity of Chief Mountain, which lies to the north, is said to be 7 miles in a horizontal direction. Under these conditions it is ap- parent that rocks occupying the surface throughout the adjoining plains on the east will in their westward extension pass under the higher portions of the mountains instead of extending normally up 28 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. their flanks, thus producing structural relations not favorable to the occurrence of artesian water in the western part of the Great Falls region. From observations made in the vicinity of Cascade, the northern end of the Big Belt Mountains is formed by extensive masses of igneous rock penetrating upper Cretaceous sediments, which are in some places horizontally bedded and in others sharply folded. It is possible that the overthrust fault which extends along the face of the Lewis Eange turns eastward along the northern side of the Big Belt Mountains, but this point was not ascertained in the field. WATER RESOURCES. SOURCE. The source of water supply of the Great Falls region is found mainly in the adjoining mountain ranges. These mountains rise to altitudes of 8,000 to 10,000 feet, where there is a relatively large pre- cipitation and a heavy snowfall. They are covered to a greater or less extent by coniferous forests, and thus serve as natural reservoirs regulating the run-off of the district. The numerous streams travers- ing the Great Falls region head high in the slopes of the adjoining mountains. Here they gather a large amount of water from melting- snow, which is carried out of the mountains into the plains or is absorbed by the upturned edges of the porous rocks over which the streams pass, thus becoming available as artesian water lower down on the plains when the overlying impervious strata are penetrated by well borings. Extensive fires have denuded much of the mountainous land which was formerly densely forested, leaving bare rocks and dead timber and causing the run-off to be more rapid. SURFACE WATERS. STREAMS. MISSOURI RIVER. The principal stream of the district is Missouri River. It enters the area near Cascade and flows in a northerly direction to the vicin- ity of Great Falls, where it changes to a more easterly course, con- tinuing thus to the border of the field. That portion of the stream lying above Great Falls flows in a meandering course through a wide valley, but below this point it enters a narrow valley with precipitous bluffs, passing over a number of cataracts collectively known as the Great Falls of the Missouri River (PL III, A and B, and PL IV, A and B). The drainage area of Missouri River at Cascade, Mont., is estimated at 18,295 square miles. Its largest tributaries from the south are Smith River and Belt Creek, and from the west and north Sun and Teton rivers, the latter entering the Missouri in the vicinity of Fort Benton outside of the area to which this report relates. U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 221 PL. Ill A. DAM AT BLACK EAGLE FALLS AND THE ANACONDA CONSOLIDATED COPPER AND MINING COMPANY'S SMELTERS. GREAT FALLS, MONT. ' ! -im/'.r B. RAINBOW FALLS OF MISSOURI RIVER, 4 MILES BELOW THE TOWN OF GREAT FALLS, MONT. SURFACE WATERS. 29 There are a number of medium to large size intermittent streams with relatively large drainage areas entering the river from either side. Those from the south are Bird Creek, Castner Coulee, Sand Coulee, Box Elder Creek, and Eed Coulee, and from the west Little Muddy Creek. The flow of Missouri River is by no means constant, but varies greatly with the season. According to discharge measure- ments made at Cascade, Mont., during four consecutive years from 1902 to 1905, inclusive, it had a maximum flow of over 22,000 second- feet and a minimum of about 1,800 second- feet, the mean varying from about 2,000 to 18,000 second-feet. As previously stated, the greatest volume of water is carried by the stream during the months of June and July, and the low-water mark is generally reached in the month of September. The results of observations made on the flow of Missouri River at Cascade are given in the following table : Estimated rate of discharge of Missouri River at Cascade, Mont., 1902-1905, by months. [Measurements made by W. W. Schlecht and L. V. Branch.] Date. July 17-31 August September. October November . 1902. April May June July August September. October November . December . 1903. January . February March . . . 1904. Discharge in second- feet. Maxi- 6,900 2, 950 2,305 2,950 4,030 9,300 12, 700 22, 700 12, 700 3,420 2,550 3,170 6,300 9,900 Mini- 3,170 1,810 1,915 2,380 2,550 4,730 7,700 12, 100 2,845 2,090 1,970 2,645 3,170 2,740 Mean. 4,847 2,171 2,057 2,720 3,176 6,536 9,958 17,953 7,302 2,372 2,274 3,056 4,470 a 6, 000 a6.000 a 6, 000 Date. 1904. April May June July August September October November December 1905. March April May June July August September October November 1-27 Discharge in second- feet. Mini- mum, mum 12, 830 21,710 20, 600 11, 350 3,480 2,380 3,600 3,600 4,490 3,930 4,320 4, 320 10, 410 10, 070 2.900 2,020 2,600 3,930 5,150 12, 090 11, 350 3,600 2,305 1,915 2,465 3,260 2,740 3,340 3,120 3,450 4,060 2,600 1,800 1,720 1, 720 2,600 Mean. 14, 925 16, 660 7,436 2,898 2,167 2,979 3,416 3, 597 3, 721 3,635 3,944 8.081 4,518 2,147 1,929 2,159 3,158 a Estimated. Discharge measurements of Missouri River at Cascade, Mont., in 1902 and 1906. [Drainage area, 18,295 square miles.] Date. Hydrographer. Second-feet. 1902. July 21 5,537 1,891 3,131 6,190 September 9 . . . November 6 . . . 1906. April 24 G. Edson May 12 do 7,880 14,400 10, 400 June 3 do June 25 Edson and Richards August 20 R. Richards 2,300 September 17 . . Grover and Richards . . 2,620 October 31 R. Richards 3,480 30 GEOLOGY AND WATEKS OF GBEAT FALLS KEGION, MONT. According to measurements of the flow of Missouri River, made by E. T. Nettleton in September, 1891, this stream loses 834 second- feet of water between the town of Great Falls and Fort Benton, a distance of about 45 miles. These measurements are supposed to have taken into account the amount added to Missouri River by Belt and Highwood creeks and by Giant Springs. That from the former two is inconsiderable, but the latter adds materially to the total flow. SUN KIVER. Sun River, the largest tributary of Missouri River in this district, rises high in the Lewis Mountains. The main stream is formed by the junction of North and South forks of Sun River, which takes place about 3 miles northeast of Augusta in the northwest corner of T. 8 N., R. 5 W. From this point the stream pursues an easterly course through an open valley to Great Falls, where it joins Missouri River. The area drained by Sun River comprises the greater portion of that part of the high eastern slope of the Rocky Mountain Front Range extending from parallel 47° 30' to 48° and a portion of the adjoining Plains province 25 to 30 miles wide extending from the base of the mountains eastward to the vicinity of Great Falls. The high moun- tainous portion of its drainage area is covered with snow throughout the greater part of the year, while on the adjoining plains more arid conditions prevail. The principal tributary of Sun River from the north is Muddy Creek, which drains the high plateau between Sun and Teton rivers, emptying into the Sun near Vaughn. It is an in- termittent stream of minor importance. From the south Sims Creek joins Sun River near the town of Sims, and a few miles farther west Spring and Dry creeks come in from the same side. Sun River has a large flow of water, the maximum being reached during the early summer months when the largest amount of snow is melted on the mountains. By far the greater part of the water of this stream comes from North Fork of Sun River, which is several times larger than South Fork, having its drainage area higher on the slopes of the Lewis Mountains. Discharge measurements of Sun River at the town of Sun River, about 20 miles above its mouth, are given below : Discharge measurements of Sun River at Sun River, Mont., 1906. Date. Hydrographer. Second-feet. April 10 April 15 May 3 Morse and Edson 344 H . M . Morse 359 G. Edson 684 May 21 do 1,240 May 22... do 1,160 May 30... do 2,140 1,510 Edson and Richards July 16 . 506 do 74 ...do 204 Follansbee and Richards 396 November 16 . . do hi. 440 " See Bibliography, p. 9. Ice running ; value doubtful. A. CROOKED FALLS OF MISSOURI RIVER, NEAR GREAT FALLS, MONT. B. BIG FALLS OF MISSOURI RIVER, 9 MILES NORTHEAST OF GREAT FALLS, MONT. SUKFACE WATEES. 3±- SMITH RIVER. Smith River has its source far to the southeast in the vicinity of the Castle Mountains, and flowing northwest drains the highland area between the Big Belt and Little Belt mountains. It enters the area described near the center of the south line of T. 17 N., R. 3 E., and flowing in a northeasterly direction joins Missouri River at a point near Ulm. Within the area described the stream flows in a meander- ing course through a deep but narrow valley. The gradient of the lower course of the stream is about 7 feet to the mile. The largest tributary of Smith River is Hound Creek, entering from the west, near Orr. It drains the northern end of the Big Belt Mountains, some of its tributaries extending high up the slopes of that range. From the east three intermittent streams enter Smith River — Boston, Ming, and Goodwin coulees. Smith River has a flow of nearly 400 second-feet during the months of May and June, but in the late fall its flow is very much smaller, as is shown by the following discharge measurements : Discharge measurements of Smith River at Truly, Mont., 1905-6. Date. Hydrographer. Second-feet. 1905. March 7 Porter and Bird 163 May 11 125 September 1 . . . A. P. Porter 31 1906. April 9 Morse and Edson 423 May 11 G. Edson 397 July 12 R. Richards 317 November 28 . . .....do a 79. 9 Wading section. TETON RIVER. The northern portion of the area treated in this report is drained by Teton River. This stream has its source on the eastern slope of the Lewis Mountains, but it does not extend far back into the uplift. After leaving the mountains it pursues a southeasterly course to the vicinity of Chouteau, where it makes a pronounced bend and flows northeastward past Collins and joins Missouri River in the vicinity of Fort Benton. Its largest affluents are Muddy and Deep creeks, the former entering from the northwest below Collins, and the latter from the south near Chouteau. These streams both rise in the foot- hills of the mountains and have a continuous flow throughout the year. The flow of Teton River is not large, especially in the vicinity of Chouteau, but near the mountains the amount is greater. At a point about 7 miles above Chouteau the stream bed is often dry throughout the late summer months, but, while the surface flow of this portion t)2 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. of the stream is small, there is apparently a very strong underflow. Spring Creek, a tributary of this stream, is formed by a number of springs having their source in the valley wash. It rises in Teton Val- ley in the northwest part of T. 24 N., E. 5 W., and flows roughly parallel to Teton River at a distance of one-half to three-fourths of a mile from it for about 10 or 12 miles to where it enters the main stream. Discharge measurements of Teton River have been made near Belleview and in the vicinity of Chouteau. These are given in the following tables : Discharge measurements of Teton River near Belleview, Mont., 190-'{-1906. Date. Hydrographer. Second-feet. 1904. A. P. Porter 58 1905. May 8 Stockman and Porter 48 October 12 Gordon Edson 56 do 51 1906. April 12 May 9 G. Edson.' 25.2 do 43.1 June 22 17 Discharge measurements of Teton River near Chouteau, Mont., 190J/-5. Date. Hydrographer. Second-feet. 1904. A. P. Porter 7.3 1905. May 9 Stockman and Porter 8 October 13 . . . 3 1906. April 13 Mav9 7.2 G. Edson 4.6 7.8 BELT CREEK. This stream rises in the northern part of the Little Belt Moun- tains, flows north across the east-central part of the district, draining the territory lying west of the Highwood Mountains, and entering the Missouri about 12 miles northeast of Great Falls. It is a vig- orous mountain stream, which carries a large flow of water in its upper course throughout all seasons of the year, especially near the mountains, but at the town of Belt all this water sinks to an under- flow (see PI. II, A) during the late summer months, leaving the stream bed dry. The loss is probably due to the fact that soft porous sandstone forms the floor of Belt Creek valley. A view of the dry SUKFACE WATERS. 33 bed of Belt Creek is shown in PL II, A. From a short distance below the town of Belt to its mouth the stream has a small but con- tinuous flow. Discharge measurements above the town of Belt are as follows: Discharge measurements of Belt Creek near Belt, Mont., in 1905-6. Date. Hydrographer. Second-feet. 1905. 8.0 May 12 7.8 A. P. Porter 578 1906. April 20 May 18. G. Edson 4.62 do 160 May 19 do 155 do 357 July 14... 190 November 10 . . Follansbee and Richards 3.55 OTTER CREEK. Otter Creek is one of the largest tributaries entering Belt Creek from the east. It rises on the northeastern slope of the Little Belt Mountains near Barker and flows north for about 6 miles, thence northwest, joining Belt Creek near Armington. It receives several small spring-fed tributaries from the south, including Little Otter Creek, Bundy Coulee, Swan Coulee, and Ford Creek. Its branches from the north, which have their source in the Highwood Mountains, are Williams and Cora creeks — the former entering near Spion Kop and the latter 2 miles above its mouth. No discharge measurements have been made of Otter Creek, but it has considerable water through- out all seasons of the year, which is supplied mainly by a number of large springs along its course. OTHER SMALL STREAMS. The area lying between Belt Creek and Smith River is drained by Box Elder Creek and Sand Coulee. Box Elder Creek rises on the high plateaus about 3 miles west of Riceville, flows northward in a direction roughly parallel to Belt Creek, and enters the Missouri about 9 miles northeast of Great Falls. This stream carries only a small flow of water. Sand Coulee, an intermittent stream with a large drainage area, is formed by the union of several small canyon tribu- taries southeast of Stockett. It continues northward to a point about 6 miles below Stockett, where it makes a sharp turn to the west and meanders through a wide level-floored valley for about 7 miles, enter- ing Missouri River about 4 miles above Great Falls. That portion of its valley through which the stream flows from the point where it makes the sharp turn to the west is a part of the preglacial valley of 54572— irr 221—09 3 34 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. the Missouri, which extends from the mouth of Sand Coulee eastward to Box Elder Creek and then northeastward to near the mouth of Belt Creek, where it reunites with the present channel. East of Otter Creek there is a prominent ridge constituting a low divide between the Highwood and Little Belt mountains which has been named the Otter Creek divide. East of this divide the drainage is all to the northeast into Arrow Creek, which is a small tributary of the Missouri, entering a short distance above the mouth of Judith Eiver. Arrow Creek, which has its source on the southern slope of the Highwood Mountains, flows eastward, passing out of this district in T. 18 N., R. 11 E. Its principal affluent is Surprise Creek, which rises at the base of Wolf Butte and pursues a northeasterly course, uniting with the main stream outside of the area here described. Running Wolf Creek rises higher up the slopes of the Little Belt Mountains farther to the southeast and flows northeasterly past Stan- ford Buttes, joining Judith River outside of the district. East of Running Wolf Creek there are several small creeks crossing the ex- treme southeast corner of the district which belong to the Judith River system. These are Skull, Willow, and Sage creeks. LAKES AND SWAMPS. The lakes occurring within the Great Falls district are of two kinds — those on the table-land, which hold flood water during a small portion of the year, and the artificial lakes, which are used as storage reservoirs for the most important irrigation systems. The largest of the natural lakes is Benton Lake, located on the highlands about 9 miles nearly due north of Great Falls. It is about 1 mile wide and 2^ miles long, and is said to have formerly held water all the year. At present the flood water which it receives during the spring sinks away, leaving the lake bed dry throughout the entire summer. It is situated in front of the terminal moraine of the Keewatin ice sheet and is probably of glacial origin. Freezeout Lake, situated in the center of an area of glacial lake deposits in Freezeout Basin, holds a small amount of water a portion of the year. There is also another small, dry lake on the plains about 3 miles southeast of Dutton. Northeast of Priest Buttes are two artificial lakes, known as Priest Lakes, which are formed by seepage water from the Cascade Land Company's canal, and south of Ralston Gap there is a small lake used as a storage reservoir. Lakes or reservoirs are of frequent occurrence throughout the district. One of considerable size is found on the table-land north of Lowry, and another, now abandoned, south of Square Butte, in the Little Muddy Creek valley. Many other smaller lakes of this character are found throughout the district, the locations of which are given on the geologic map. On Burton Bench, near UNDERGROUND WATERS. 35 Teuchot home ranch, there are a number of small lagoons or lakes fed by springs which contain water throughout the year. To the west of the area treated in this report and along the base of the Lewis Mountains there is a zone in which local mountain glaciers have deposited morainal material over wide districts bordering the larger streams. Throughout these glaciated areas there are innumer- able small lakes and swamps which furnish water to the mountain streams crossing them. UNDERGROUND WATERS. GENERAL STATEMENTS. The water-bearing rocks of the Great Falls region are confined mainly to the basal Colorado and the Kootenai formations, where a number of sandstone beds occur which are porous and imbibe water freely when conditions are favorable. There are other formations within the district that have sandstones that probably contain more or less water. These are the Eagle and Claggett sandstones of the Montana formation and the coarse-grained conglomeratic sandstone of the Ellis formation. Around the sides of Square and Fort Shaw buttes a number of small springs issue from the base of the Eagle sandstone. In the Kootenai formation several water-bearing horizons are found. The massive gray sandstone overlying the coal, which ranges in thickness from 25 to 80 feet, is the source of a number of springs along Otter Creek, and wherever the coal is mined, especially where the sandstone forms the roof, considerable difficulty is en- countered with water from this formation. Above the sandstone overlying the coal there are a number of massive sandstones inter- bedded with red shale, which, when they occupy summits of plateaus, have numerous small springs issuing from their base. These Kootenai sandstone beds are the sources of numerous small springs wherever they are exposed from the eastern margin of the field to Smith River. West of Stockett, however, they are overlain by basal sandstones of the Colorado, which cap the plateau summits west and south of Sand Coulee, extending to beyond Missouri River and in- cluding the bench land north of Ulm. Throughout this area springs are of frequent occurrence at the base of the Colorado sandstone, and wherever well borings on the summits of the plateau have entered this sandstone a good supply of water has usually been obtained. SPRINGS. DISTRIBUTION. One of the most valuable sources of domestic and stock water supply in the Great Falls district is found in the numerous springs which occur along the upper courses of the smaller mountain streams 36 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. and in the valleys of the larger streams throughout the lower Plains country. Along the northern slope of the Little Belt Mountains springs are very abundant. The zone bordering the mountains is essentially a plateau region traversed by numerous mountain streams which flow through deeply cut valleys. In the bottom of these val- leys and along their sides at different elevations above the streams springs of moderate flow occur at frequent intervals. Their source is the various water-bearing sandstones of the Kootenai formation, which extend southward far up the slopes to the high hilly zone bor- dering the mountains where there is an increased precipitation, and the sandstones absorb a large amount of water. Lower down on the plains the mountain streams cut and expose these sandstones, leaving the water free to escape as springs in the sides of the plateaus and in the lower portions of the valleys. Springs of this character are most abundant along Otter and Belt creeks, Sand Coulee, Smith Eiver, and their principal tributaries (see PI. V,A). They are usually not large, but afford a steady supply of good water when properly developed. West of Missouri River springs are less numerous. Several are found issuing from the base of the Eagle sandstone on the sides of Square and Fort Shaw buttes. At one locality on the west side of Square Butte water from a number of these small springs which have been developed is piped 2 miles to the Toman stock ranch, where it is utilized for domestic purposes (see PL II, B). On the north side of Sun River the high gravel-capped plateau is more or less dissected by canyons leading southward. In these canyons and in the heads of coulees tributary to them springs are frequent. They have their source in the gravel terrace which caps the plateau, or in the under- lying Eagle sandstone. The flow, though not large, is continuous, the water being used mainly for stock purposes by the Flowerree Cattle Company. A few small springs are found along Muddy Creek of Sun River northwest of Vaughn and along the base of the bluffs at the upper end of Burton Bench. In Sun and Teton River valleys there are a few large springs which derive their water from the underflow of these streams. Probably the largest spring of this character is found in Teton Valley about 7 miles above Chouteau, where a sufficient amount of water issues from the valley wash to supply a stream of considerable size, known as Spring Creek. In Sun River valley at Lowry is a spring of similar size, which is utilized for both irrigation and stock purposes. This spring has a large flow of excellent water, which enters Sun River a short distance below Lowry. Another spring, somewhat smaller, is found on the opposite side of the river at Skinner and Heikie's ranch, and farther down the river, a short distance above the intrusive dike which crosses Sun River valley about 1 mile west of Fort Shaw, there is a small area where numerous springs issue U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 221 PL. V A. SPRING AT BASE OF COLORADO SANDSTONE, 12 MILES SOUTH OF GREAT FALLS, MONT. B. GIANT SPRINGS, NEAR GREAT FALLS, MONT. UNDERGROUND WATERS. 37 from the valley wash. Springs are not infrequent in Sun River val- ley between Lowry and Augusta. At Sam Larkin's ranch, 6 miles below Augusta, a spring issues from the base of a low gravel-capped terrace, and has a strong flow of water throughout the year. Other springs of a similar character examined in this part of Sun River valley are given in the table on pages 42-50, with their source, quality, and approximate yield. A few springs are found along Missouri River between Cascade and Great Falls which are used for domestic and stock purposes, although in the majority of cases in this vicinity the water supply is derived from shallow wells. Along the base of the Big Belt Mountains on the east side of the river springs are more numerous, and in many instances they have been given the chief consideration in locating ranches. GIANT SPRINGS. Near Great Falls are some very large springs which present unique geologic features and an interesting question as to the source of the water (see PL V, B). These springs, locally known as Giant Springs, are located on the south bank of Missouri River about 3 miles below Great Falls. They have a very large flow of relatively pure water, which appears at the surface through large joints in a medium to coarse-grained sandstone belonging to the Kootenai or lower Cre- taceous rocks. On either side of the main spring for a short distance are smaller springs flowing from the joints, and directly opposite it in the bed of the river there is a large spring, which is apparent during low water. The Giant Springs were discovered by Captain Lewis, of the Lewis and Clark Expedition, in 1804, and in his description were spoken of as the " largest fountain in the United States." According to measurements made by E. T. Nettleton a the flow of these springs is approximately 638 cubic feet per second, an amount which, converted into gallons, is the equivalent -of over 400,000,000 gallons every twenty-four hours — a veritable underground river. The fact that the water of Giant Springs issues from rocks at the water's edge and in the bed of the river renders it difficult to measure their exact flow. In order to ascertain this amount, meas- urements were taken of the total flow of Missouri River above and below the springs; the difference between these two measurements is assumed to be the quantity furnished to the river by the- springs. It is readily seen from the above figures that these springs rank among the largest in the United States. The water, which boils up with considerable force, is clear, blue, and relatively pure, containing no more dissolved salts than the average well water of the region. It has a temperature of about 50° F. a See Bibliography, p. 9. 38 GEOLOGY AND WATEES OF GREAT FALLS REGION, MONT. No spring deposits occur in the immediate vicinity of Giant Springs, and the water is not generally regarded as possessing thera- peutic value. It is not utilized at present, but is alloAved to flow into the river. There are, however, a few improvements, such as sidewalks, etc., which make it possible for tourists to view the springs from the most advantageous points. A chemical analysis of the water was made several years ago by James A. Dodge, of the University of Wisconsin, and a field analysis of the water was made during the past field season by W. R. Calvert. These analyses are given below. Analyses of water of Giant Springs near Great Falls, Mont. MINERAL ANALYSIS. [Grains per gallon. 1 CaSO* 14. 04 CaC0 3 4. 38 Mg00 3 4. 98 NaCl . 56 Traces of borates and potassium and lithium. FIELD ANALYSIS. [Parts per million.] Turbidity Color Iron _ Calcium Moderate. Total hardness 97 Total alkalinity 340 Alkaline carbonates Alkaline-earth carbonates , 339 Sulphates 300 Chlorides 10 From a careful study of the geologic relations in the vicinity of Great Falls, it is believed by the writer that the water of Giant Springs is derived from the subriver flow of the Missouri which leaves the valley of that stream near the mouth of Sand Coulee as an underflow and passes down its preglacial channel, which extends up Sand Coulee, into Gibson Flat, an oxbow in the old river channel. From here by a subterranean passage through porous Cretaceous sand- stone and sandy shale, which dip in a favorable direction for its trans- mission, it makes its escape to the present Missouri River, where it appears in the form of Giant Springs (see Pis. V, B, and VI). It is further believed by the writer that the jointing, which is here well developed with the major joint planes extending in a north-south direction, is an important factor in the underground movement of the water. It is also possible that a fault in this vicinity further facilitates the underground passage of the water, but no positive U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER NO. 221 PL. VI MAP OF GREAT FALLS DISTRICT, MONTANA, SHOWING PREGLACIAL CHANNEL OF MISSOURI RIVER AND COURSE OF UNDERGROUND WATER. UNDERGROUND WATERS. 39 evidence of this was seen. Well borings in lower Sand Coulee and Gibson Flat demonstrate that the materials filling the old valley are largely coarse river sediments, well adapted for rapid percolation of water. From the above it is readily seen that along the supposed under- ground course of the water from the mouth of Sand Coulee to where it appears at the surface as springs, the physical conditions are such as to permit the passage of a large volume of water, an amount be- lieved to be equivalent to that furnished by the Giant Springs. WELLS. While springs are the principal source of domestic water supply in the Great Falls region, there are a number of localities, especially in the larger valleys, where the greater part of such water is derived from shallow wells rarely exceeding 20 feet in depth. On the sum- mits of some of the plateaus bordering the Little Belt Mountains, where dry farming is successfully practiced, wells obtain water at depths varying from 100 to 300 feet, depending on the locality. To the west and north of Great Falls, throughout the highland districts, wells are usually shallow, rarely being sunk below the base of the gravel terraces, which vary from 25 to 40 feet in thickness and cover extensive areas. In the larger valleys traversing the western part of the district wells are usually shallower than those on the highland, and water is more abundant. Throughout Burton Bench, north of Teton River, they vary from 20 to 100 feet, the deeper ones being artesian. A few deep wells have been dug in the vicinity of Great Falls, three by the Great Falls Meat Company on the table-land east of Great Falls, two by the Copeland Brothers near the south end of Sun River bridge, and others farther up Missouri River, one on Odell ranch and another at Ulm. The deepest boring in this portion of Montana occurs about 6 miles east of Dutton, where an oil prospect hole, known as the Banatyne well, has been sunk to a depth of 1,500 feet. Records of the Copeland Brothers, Banatyne, and Odell wells are given below, and on subsequent pages occur well tables giving the location, depth, quantity, and quality of water of a number of representative wells in the Great Falls district. Records of Copeland Brothers' wells near the south end of Sun River bridge, Great Falls, Mont. WELL NO. 1. Feet. Fine sand 0- 4 Gumbo 4-15 Blue clay 15-31 Sand and gravel, water bearing 31-33 Red sandstone- 33-43 40 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. Records of Copeland Brothers' wells near the south end of Sun River bridge, Great Falls, Mont — Continued. WELL NO. 1— Continued. Feet. Ferruginous sandstone 43- 47 Blue shale 47- 59 Gray shale 59- 85 Gray sandy rock 85-100 Light-red rock 100-105 Dark-red rock 105-112 Gray compact sandstone 112-122 Blue shale i 122-134 Red rock 134-144 Sandstone with shaly layers 144-147 Light-red rock— __ 147-157 Soapstone 157-227 Impure sandstone 227-229 Gray shale 229-244 Impure sandstone 244-247 Gray shale i 247-252 Impure sandstone 252-255 Gray shale. 255-263 Impure sandstone 263-265 Gray shale. 265-277 Sandstone and shale. 277-282 WELL NO. 2. Fine sand 0- 8 Medium fine sand 8- 25 Gumbo 25- 36 Blue clay 36- 52 Red rock 52- 62 Ferruginous sandstone. 62- 66 Blue shale 66- 81 Red rock 81-103 Fine gray sandstone 103-107 Light-red rock 107-123 Blue shale 123-131 Gray sandstone 131-143 Brown shale 143-157 Gray shale 157-167 Soapstone 167-207 Light-red rock 207-219 Impure sandstone 219-223 Dark-red rock 223-233 Black shale 233-247 Light-red rock 247-250 Gray shale. 250-260 Impure sandstone 260-263 Gray shale. 203-265 Impure sandstone 205-260 Blue shale 266-274 Impure sandstone 274-276 UNDERGROUND WATERS. 41 Records of Copeland Brothers' wells near the south end of Sun River bridge, Great Falls, Mont — Continued. WELL NO. 2— Continued. Feet. Dark shale. 276-280 Impure sandstone 280-283 Gray shale_ 283-289 Blue sandstone. 289-297 Brown shale 297-300 Blue sandstone 300-310 Impure limestone 310-318 White limestone 318-370 Brown limestone 370-417 White limestone 417-459 Blue limestone 459-519 Impure limestone 519-541 Brown limestone 541-569 Blue limestone 569-581 White limestone _■ 581-643 Record of Batiatyne well, 6 miles east of Dutton, Mont. Feet. Yellow clay 0- 74 Shale 74- 280 Sand, containing salt water and gas 280- 285 Sandy shale 285- 358 Black sand 358- 365 Shale 365- 500 Sand, containing salt water 500- 509 Sand and gritty shale 509- 605 Soft, white conglomerate 605- 780 Hard conglomerate 780- 870 Fine blue sand 870- 880 Hard blue shale 880- 900 Hard shale in thin layers 900- 950 Dark-blue shale 950- 975 Black shale 975-1,040 Hard bluish sandstone 1,040-1,130 Black shale -_ 1,130-1,160 Red limestone 1,160-1,200 Red sandstone 1,200-1,240 It is believed that the so-called red limestone encountered at a depth of 1,160 feet below the surface represents the upper part of the Kootenai formation. Record of Odell well in Missouri River, south of Great Falls, Mont. Feet. Alluvium 0- 20 Sand 20-145 Clay 145-205 Gravel 205-212 42 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. ha*- ■3*3 § 303 go o . 00 05 o a o s S3.93 w ificofl A 02 GO ' • O O S o fi«3 CD M §9 Po2 I . . 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TJ 'OTJ T3 oS ; : : '• "O'O'O'O'OTS'U'O T3T3 h j : j : £ pi 3 O c O O O 00000000 O O "O Xl "O t3 TJ X) "D "D 73 T3 +j ; ; j j H : : : : •i5t^0005O^cNe>0 •* 10 fe " ^Hrt " 1-1 1-1 UNDERGROUND WATERS. 59 o o mi . -P 03 fto pj O £ Oil) £ £ cs o o o o as O bD I CO CO i-l rH OOCOCOCOCOIMCOCNC^ I CO O COM coco i-H &3 2fl oooooooo S o o' hOib CB 6 ffl O S co « a ftg iz; £ w ^ ^ s ^ ^ £ £ fc Eh ^ Eh n (N t-h - co ^ hh^ V.2 £P3 :PhHPh 0 X MOXTAXA UNDERGROUND WATERS. 63 OTTEE CREEK DISTRICT. The Otter Creek district is arbitrarily taken to include the area between Otter Creek divide and Belt Creek. It has an abundant w ater supply, which is derived largely from springs. A few shallow wells are found along Belt Creek valley and its tributaries, especially in the vicinity of Belt. Shallow wells are also not infrequent on the higher slopes bordering the Highwood and Little Belt mountains. Along Otter Creek numerous springs from the Kootenai sandstone occurring at frequent intervals either in the bottom of the valleys or on the sides of the bluffs furnish an ample amount of good water and make it generally unnecessary to sink wells. The tributaries of Otter Creek from the south, which drain the high plateaus, are also well supplied with spring water from the same source. North of Otter Creek, especially on the higher slopes bordering the Highwood Moun- tains, there is a strong underflow in the bottom of all the coulees, which is derived from melting snow higher on the mountain slopes. The water thus absorbed in the heads of the coulees high on the slopes appears at the surface lower down in their course in the form of small springs, or it can be easily reached by shallow wells. GREAT FALLS DISTRICT. Under the Great Falls district is described the territory lying south of Missouri River between Belt Creek and Smith River. As stated above it is essentially a plateau region more or less dissected by can- yons. Throughout the lower part of the district, on the plains east of Great Falls, water for domestic purposes is apparently difficult to obtain, excepting along Box Elder Creek valley, where a number of shallow wells furnish a large amount. Several wells have been dug by the Great Falls Meat Company immediately east of Great Falls. The depths of these vary from 150 to 300 feet, and in no instance has the quality and quantity of the water been entirely satisfactory. Farther to the south and east springs are the chief source of water supply, although a few wells have been sunk. As a .rule wells in this portion of the district are not successful, and it is believed that the most satisfactory source of domestic water supply is to be found in the development of the small springs which are more or less abundant. At Stockett and Sand Coulee a few wells have been bored, which are described on page TO, and on the high plateaus southeast of these towns deep borings have been made, which usually failed to secure a satisfactory amount of water. In the vicinity of Stockett there is a local doming of the formations, which exposes the Madison limestone for a considerable distance along Sand Coulee and in Cottonwood and Straight coulees. Wells sunk in this limestone fail to find water, for the upper part of the formation is not water bearing. The Juras- sic and Cretaceous formations overlying the Carboniferous limestone 64 GEOLOGY AND WATEKS OF GREAT EALLS REGION, MONT. in this vicinity are relatively thin, but they thicken to both the east and the west. Wells bored on the plateaus penetrate the water-bear- ing sandstone of the Kootenai formation within a distance of 200 to 300 feet from the surface. This sandstone in the vicinity of Stockett and Sand Coulee is not heavily saturated with water, notwithstanding that it is the source of many small springs. The scarcity of water is probably due to the fact, as previously described, that in its southern extension the sandstone caps the higher hills, where the only water which it can absorb is from rainfall and melting snow. In sinking a well in this general region whenever the limestone is reached the boring should be discontinued, for it indicates that all the water- bearing rocks of the region have been penetrated. Along the west side of the district, where the plateaus are capped by the basal sand- stone of the Colorado, springs are abundant along the side of the plateaus (see PL V, A), and in the valleys good water is obtained from shallow wells. Representative wells and springs in the Great Falls district are listed on pages 43-44 and 53-55. MISSOURI RIVER VALLEY DISTRICT. Along Missouri River valley from the base of Big Belt Mountains to a point about 2 miles above Riverdale there is a wide, open valley on the east side of the river in which an abundance of good water is obtained from wells at depths varying from 15 to 25 feet, depending on the distance from the river. A few wells in this valley have been sunk to greater depths in order to obtain a larger supply of water, but generally they have not been successful. Several unsuccessful attempts have also been made to secure artesian water in the valley. This is not practicable, owing to the adverse structural relations de- scribed on page 27. The water of shallow wells is derived from allu- vial sands and gravel, which have a variable thickness. To the east, on the summit of the high plateau bordering Smith River on the west, water is secured from wells at a considerably greater depth. Here the principal water-bearing horizon is the basal sandstone of the Colorado formation. Wells along this plateau vary from 50 to 150 feet, and a sufficient quantity of water is usually obtained. The ex- tent of the basal Colorado sandstone in this region is shown on the geologic map (PL I). ULM BENCH. Throughout Ulm Bench, which lies southwest of Great Falls be- tween Missouri and Sun rivers, dry farming is extensively practiced, and the district has been divided into a number of small farms. On these farms wells have been bored which invariably obtain good water at depths rarely exceeding 100 feet. The water is derived from the lower part of the basal Colorado sandstone which caps Ulm Bench. Along the western margin of Ulm Bench, where the over- UNDERGROUND WATERS. 65 lying Colorado shale occupies the surface, the well water is generally more or less mineralized and unfit for domestic purposes. AREA SOUTH OF SUN RIVER. West of Ulm Bench throughout the district lying south of Sun River the prospects for underground water are not favorable. The formation occupying the surface in this region is the Colorado shale, which rarely if ever contains pure water. The principal drainage of the area is Little Muddy Creek, a large intermittent stream draining a considerable district south of Square and Fort Shaw buttes. From several field analyses which have been made of water from wells in this valley it has been found to contain an unusually large amount of magnesium and other harmful salts. The well water in this region is so highly mineralized that it is rendered unfit even for stock purposes. The Eagle sandstone, which with the overlying igneous rock caps the prominent buttes in this region, is the only near source of potable water supply. West of Crown Butte throughout the lower part of the territory drained by Sims Creek prospects for underground water are more favorable. Here the Eagle sandstone underlies the surface, and, while no practical tests have been made, it is believed that wells sunk in this sandstone will probably secure good water. SUN RIVER VALLEY. Along the valley of Sun River water for domestic and stock pur- poses is derived from wells and springs or taken directly from the river. In the lower part of the valley between Sun River and Great Falls many shallow wells have been sunk which furnish a good supply. These derive their waters mainly from the valley wash. Farther up Sun River valley throughout the lower land water is obtained from shallow wells, but back from the streams the depth increases. At Fort Shaw a well was recently drilled and good water found at a depth of 101 feet. This, however, was at the mouth of a small coulee entering Sun River from the south, and it is possible the well did not penetrate the valley filling. In the vicinity of Augusta water is secured from wells at depths varying from 10 to 15 feet, but here the greater part of the domestic water supply is taken directly from Sun River, where, owing to the nearness to Lewis Mountains, it is relatively pure. The prospects for water from deep wells in Sun River valley are very poor, especially in the lower part. Between Manchester and Sims well borings extending through the valley filling will enter the nonwater-bearing Colorado shale, which has a thickness increasing from zero at Manchester to over 800 feet at Sims. Between Sims and Augusta wells sunk below the bottom of the valley 54572— irr 221—09 5 66 GEOLOGY AND WATEKS OF GREAT FALLS REGION, MONT. filling would enter the lower part of the Montana, which consists of sandstone and shale in alternating succession. The basal sandstone, comprising the Eagle formation, probably contains water, but the shale overlying the sandstone is believed not to be water bearing. HIGHLANDS NORTH OF SUN RIVER. Throughout the high plateau region between Sun and Teton rivers the prospects for underground water are not generally favorable. On that portion of the region lying west of Freezeout Lake no wells, so far as could be ascertained, have been bored which would test the water capacity of the extensive gravel terraces capping the highland, but it is evident from the numerous springs along their eastern mar- gin that they contain more or less water. Underneath the gravel of this district occur the Eagle and Claggett sandstones, which are also water bearing, so that it is believed little difficulty would be encoun- tered in securing a good supply of water from wells in this part of the field. On Freezeout Bench, however, a number of shallow wells have been sunk, which, with one exception, do not furnish a satisfac- tory amount of water. At Zimmerman's ranch a well 30 feet deep supplies only a small amount of alkali water, while 3 miles to the southwest, at Kruck's ranch, a good well of potable water was secured at about the same depth. Freezeout Bench is composed geologically of a thin veneer of gravel lying on the nonwater-bearing Colorado shale, consequently the only water which can be expected from wells on this bench is at the base of this gravel, which has a thickness vary- ing from 25 to 40 feet. The amount of water available at the base of the gravel will probably not be large, although this may vary locally, and in many cases it is apt to be hard, as the gravel carries consider- able lime as a cementing material. Wells penetrating the gravel and entering the Colorado shale would probably obtain alkali water, as this shale rarely furnishes good water. North of Freezeout Bench in some of the coulees tributary to Muddy Creek of Sun River there are small springs fed by the gravel terraces, and here and there a success- ful shallow well. FORT BENTON BENCH. East of the Montana and Great Northern Railway, between Great Falls and Collins, is an area of featureless plains comprising several townships and locally known as Fort Benton Bench, in which the prospects for underground water are very poor. Although this area was not examined in detail, it is known that over a great part of the district the surface formation is Colorado shale. The results of the Banatyne boring, 6 miles east of Dutton, demonstrate that the surface formation and the formations underlying to a depth of at least 1,500 feet are not water bearing. Along Teton Valley, which crosses the UNDEBGKOUND WATEKS. 67 northern part of the district, shallow wells can probably be obtained from the valley wash, although no detailed examination was made of this portion of the field, and it is believed that shallow wells furnish- ing a moderate supply of water could be secured in some of the small coulees draining northwestward into Teton River. TETON RIVER VALLEY. From the west margin of T. 25 N., R. 6 W., eastward as far as the investigation was carried, and especially to the mouth of Deep Creek, there is a strong underflow in Teton Valley. Wells at Chouteau ob- tain water at three distinct horizons, the first at 7 feet, the second at 27 feet, and the third at 48 feet beneath the surface. There is no marked dissimilarity in the chemical character of the water found at these depths, and in many respects it resembles the water of Teton River. Springs occur in abundance in Teton Valley above Chouteau. Deep Creek Valley, a tributary of the Teton from the south, has a strong underflow, and an abundance of water is found at depths of 10 to 20 feet below the surface. At the head of Deep Creek are numerous small swamps and glacial lakes, which add materially to both the surface flow and the underflow of Deep Creek valley. North of Deep Creek there is a wide gravel-capped terrace extend- ing toward the mountains, throughout which water could probably be secured from wells not exceeding 30 feet in depth, the water occur- ring at the base of the gravel. North of this broad terrace there is a badlands district surrounding Teton Buttes, in which there is a scarcity of water. BURTON BENCH. Springs are not abundant in the vicinity of Chouteau outside of Teton River valley, and water for domestic purposes is sometimes difficult to obtain. An exception is found in Burton Bench, an area comprising about four townships, which lies north of Chouteau. Bench gravel, loosely cemented, caps this area, thinning gradually from a depth of 30 feet on the southwest to a mere sprinkling on the northeast. Immediately beneath this cap is impervious shale, causing the gravel to act as a reservoir for surface water. Before irrigation ditches had crossed Burton Bench water was obtained at a depth cor- responding to the thickness of the gravel, but the water plane has been gradually rising under the influence of irrigation until now an abun- dant supply is found at 10 to 12 feet beneath the surface. Outside the gravel-capped area water for stock and domestic purposes is taken di- rectly from the ditches, although it contains a considerable quantity of undesirable mineral matter. The average well has a depth of about 68 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. 60 feet, but is often too strongly impregnated with alkali to be pota- ble. A limited artesian basin of about 20 square miles occurs in the northeastern part of Burton Bench. It is described in detail in the next section. MUDDY CREEK ARTESIAN BASIN." General description. — Within an area extending about 6 miles west from where the terminal moraine of the Keewatin ice sheet crosses Muddy Creek valley in T. 25 N., K. 3 W., and having a width of about 3 miles, artesian water is obtained from coarse granitic gravel, overlain by impervious lacustrine clay, at moderate depths below the surface. The writer examined twenty-two flowing wells in this district, all of which furnish a good quality of water. Others that formerly flowed have become clogged by caving where the well was not cased. The water resources of this basin have not as yet been utilized to any great extent, partly because much of the area is used only for grazing and partly because water for irrigating purposes is readily available from the ditches crossing Burton Bench. In many cases the water is allowed to flow from the wells and no use is made of it, but in many instances outside of the ditch system it is utilized for irrigation as well as for stock and domestic purposes. Two wells in sec. 6, T. 25 N., R. 3 W., water 30 acres of alfalfa, and a group of wells in sec. 11, T. 25 N., R. 4 W., irrigate 100 acres of hay land. In general the wells are 2^ or 3 inches in diameter, as it was found b}^ experiment that a pipe of that size yielded the same flow as a larger one. The smaller size is the more advantageous, since wells of that diameter may be drilled by hand where the depth does not exceed 75 or 80 feet. The method of drilling used in this vicinity is simple. A 1-inch iron rod twisted at one end into a spiral of the diameter desired is used as an auger. The stiff clay which must be penetrated is sufficiently adhesive to allow the drill to bring up a clean core several feet in length. The wells vary in depth from 16 to 100 feet, the deeper being as a rule along Muddy Creek. The variation in depth of these wells indicates that this stream is following rather closely its preglacial channel. Although practically all the artesian wells are south of Muddy Creek, it is probable that there is likewise a considerable area north of that stream where flowing wells might be obtained if, as seems probable, the preglacial valley extends later- ally in that direction as well as south. The eastern limits of the basin are defined by the moraine, and since the head of the artesian flow is in no case great, the largest reported being 35 feet, it is not probable " The description of artesian conditions in the Muddy Creek artesian basin is by W. R. Calvert. UNDERGROUND WATEKS. 69 that a flow can be secured much farther west than the wells located in sec. 15, T. 6 N., E. 4 W., where the pressure is very weak. Source. — Brief mention has already been made (p. 61) of the prob- able source of the artesian water of Muddy Creek basin. The geologic structure of the region and the small head of the flowing wells pre- clude the theory of a distant or high source. That the artesian flows of this area are due to local conditions is evident from a study of the field. Some water may be supplied by Muddy Creek in its course through T. 26 N., E. 6 W., where the water sinks to an underflow, leaving the stream bed dry for a distance of several miles during the greater part of the year. Since apparently the entire flow reappears at the surface near Bynum, and the stream has not there cut through the lacustrine clays, it is not probable that Muddy Creek contributes much of the artesian water to Muddy Creek basin. On the contrary, the evidence indicates that the artesian basin is connected more di- rectly with the Teton through Ealston Gap. To the observer looking southwest through Ealston Gap it seems probable that the depression was once a large stream valley, and since river sand and gravel are found there the conclusion is further strengthened. From the base of the mountains until it reaches the southeast corner of T. 25 N., E. 6 W., Teton Eiver is not intrenched, but flows in a wide gravel-fillecl valley. Considerable water is absorbed by this gravel, and it is believed that there is an underflow from Teton Eiver through Ealston Gap to Muddy Creek valley. Springs in sec. 16, T. 25 N., E. 6 W., vary in their flow with the flow of Teton Eiver, the rise in the river increas- ing within a short period of time the flow of the springs. This phenomenon has been observed even during the dry season of the year, hence it is difficult to attribute this increase in the flow of the springs to any other source than the increase of Teton Eiver. A small stream north of Teton Eiver at present flows toward Ealston Gap, but as it reaches the vicinity of the gap it sinks to an underflow and prob- ably soon passes beneath the impervious lacustrine clay into the porous granitic gravel and becomes available as artesian water to the east when the overlying impervious, clay is penetrated by well borings. WATER SUPPLY OF TOWNS AND VILLAGES. There are comparatively few towns in the Great Falls region. Great Falls, the largest, derives its city water supply from Missouri Eiver about 1 mile above the business center. From the pumping station, which is located in the NW. \ sec. 14, T. 20 N., E. 3 E., the water is pumped directly to a standpipe, located on a prominent hill in the eastern part of town, which has a capacity of 560,000 gallons. From this point it is distributed by a system of 6-inch mains to the 70 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. different parts of the city. A field assay of the water taken from one of the hydrants in the main part of the city is as follows : Analysis of a sample of the Great Falls city water. [Parts per million.] Source * Missouri River. Color Iron Total hardness 125 Alkalinity 180 Alkaline carbonates 32 Alkaline-earth carbonates 160 Chlorides 25 Chouteau, the next town in importance within the district and the county seat of Teton County, depends entirely upon shallow wells for its water supply. Here water is obtained from valley filling at three distinct horizons, which, as previously stated, occur at depths below the surface of 7, 27, and 48 feet, respectively. The largest supply is usually found at a depth of 7 feet below the surface, but wells are generally sunk to the lower horizons in order to obtain water less liable to surface contamination. There is no general town system. The water supply for the town of Sand Coulee is derived from wells which show considerable variation in depth. In the valley wells are considerably over 100 feet deep. The well owned by Louis Dahn, situated in the valley in the northern part of town, is 168 feet deep. On the slope of the hills bordering the valley water has been secured at depths of 25 to 30 feet, but the supply is variable. In the sides of some of the small coulees in the vicinity of this town there are many water seeps, as previously described, which if properly developed might afford a good domestic water supply. Considerable difficulty has been encountered in obtaining water for the town of Stockett. In the northern part of the town the people depend for water largely on small springs issuing from the base of sandstone in the sides of the coulee. It has been found by experiment that these small seeps in the hillside, when properly developed, often furnish a good steady flow of potable water. Farther up the coulee, in the main part of town, the Cottonwood Coal Company has sunk a well in the bottom of the main coulee to a depth of 50 feet. From the bottom of this well a tunnel 4 feet wide by 5J feet high has been dug 90 feet to the east and 125 feet to the west, thus obtaining the greater part of the underflow of the coulee in which Stockett is built. During the driest season of the year the well has furnished 65,000 gallons per day, and the average capacity is over 100,000 gallons a day, most of which is used by the CHEMICAL CHARACTER OF WATER. 71 Cottonwood Coal Company. Wells sunk in the sides of the coulees furnish small quantities of water at varying depths. The present supply of water for both Sand Coulee and Stockett might be materially increased by the proper improvement of the numerous moist places occurring along the sides of many of the coulees. These moist places or seeps are generally indicated by the deeper green color of the vegetation. In many such localities if shallow excavations were made, water in considerable quantity would probably be obtained, which could easily be piped to houses situated in the valley, thus affording an excellent domestic water supply. The practicability of such a source of water has been demonstrated at a few places in the vicinity of Stockett and at many places along Otter Creek, where springs occur under similar conditions. It is believed also that on many of the small farms in the vicinity of Stockett and Sand Coulee a careful examination of the sides of the coulee might result in the location of moist or seepy places where by inexpensive development water could be procured. CHEMICAL CHARACTER OF AVATER. During the course of the investigation of the water resources of the Great Falls region samples of water were collected from representa- tive wells and springs for the purpose of analysis. These analyses or assays were made in the field in accordance with the method em- ployed by the water resources branch of the United States Geological Survey. This method is fully described in Water-Supply Paper No. 151. Knowledge was also desired concerning the variation, if any existed, in the quality of waters from the several formations repre- sented in the district. Although a complete analysis of the samples was not possible by the methods employed, the chief characteristics and chemical constituents were determined. These include physical properties, color and turbidity, and those depending more directly upon chemical quality, namely, the amount of iron, calcium, alkaline and alkaline-earth carbonates, sulphates, and chlorides present, and the hardness. The waters throughout the district are remarkably free from tur- bidity, only one sample possessing more than a trace. In only a few instances was the presence of coloring matter noted, and iron is a rare constituent in the waters examined. In the region east of Missouri River the great majority of springs issue from the sandstone or sandy shale of the Kootenai formation. In general the calcium and sulphate content of waters from this for- mation is high owing to the presence of gypsum in the shale. Near the southern border of the eastern portion of the district examined many springs issue from the Quadrant shale, and these are impreg- nated to a considerable extent with salts of magnesium and many are 72 GEOLOGY AND WATEKS OF GKEAT FALLS KEGION, MONT. charged with hydrogen sulphide, which renders them unpleasant for drinking. In the district where the surface formation is Colorado shale wells and surface springs are likewise apt to contain consider- able magnesium and the alkalinity is high. In the area west of the Missouri and south of Sun River, with the exception of Ulm Bench, water is relatively scarce and is obtained chiefly from the sandy members of the Montana. As above stated, the water of this district, especially in the Colorado shale area, is characterized by an abundance of magnesium salts, and the alkalinity is often so great as to render it unfit to drink. Several samples of wells and springs from this area also indicate the presence of a large amount of chlorides. In Sun River valley water is usually obtained from alluvium and is not so highly mineralized as that in the area to the south. To the north between Sun and Teton rivers but few sam- ples were taken. There are few wells in this region and springs are not abundant. The samples analyzed, however, indicate that the various members of the Montana group afford water containing more or less mineral matter. In the valley of the Teton, where water is obtained from alluvium, the mineral content, while not especially high, is considerable. On Burton Bench the chief water supply is from the gravel capping consisting principally of limestone pebbles. This gravel contains a large amount of soluble salts. The chlorine content is especially high. In spite of the mineralization, however, it is of better quality than that from wells or springs in the region to the east, where the gravel capping is absent and Colorado shale occu- pies the surface. From the artesian basin in Muddy Creek valley two samples of water were analyzed. These samples show considerable variation. No. 1, from the eastern portion of the basin, is not so highly mineralized as No. 2, obtained farther west, the difference being chiefly in the calcium and sulphate content. The following table shows the results of the analyses of waters from the various parts of the area investigated. The results are expressed in parts per million. CHEMICAL CHAEACTEE OF WATEE. 73 •anuomo 05 uj^ioo •(>os) ' £ O0^N sb sajBUoqjBO aniiBsnv • £ 00^3 sb ^inqBJH'B p^oj, sb ssaupjBq pno£ •nmioiBO •uoji •ioioo •Anpiqmj, 13 00O (M HMCN HONiOCX CO r^ lO -> 03 b o 03^ G t-i £.S>Q3W Ioob 5 9, QS>-sW oo — CQ 03 ft 03 ^coooooooooooo ft GO cs i-f (NCO^lO 74 GEOLOGY AND WATERS OP GREAT FALLS REGION, MONT. •auuomo 0)01010)010 01 OlO^Ol^O ^010101010001 t^ OS OS c^^oooo •Cos) T co o o cd co co cm lONOnno CO CMCM.-I ^HCOCM ^S! £-*< 00 CM CO OS 00 CM CMOO OXO-*^ CM -tfi H 00 CO CO t^ CM CO CM i-H O CO OOCOiOlOOS i-l CM CM i-HOi-l CM COCO -J'bd maBO-aunBJiiv Ol OS OS Ol CM CO -tf OSOIOSCOCOO CO ■* CM LO LO CO Tfi i-H OS ■"*< i-l CM lO ^H r-l t^- t^ CO CM rr CM t^ Ol CO 00 -^ CM OOHOOO^CNI 1 N(MO) O CM CM i-l CM CM CM CM CM CO CM rH CM CM CM CM CM CO CM •* rp CM CO r-i CM CO i-l ,-1 -* r-l CM OCO CM ■"*! •*> CM CMCM oooooc OOO '(MO OOOOOOOO OOO MHO sb ^itni^Jije ib;ox > Ol OS CM CO -"# OIOIOICOCOO CO tt CM lO 10 CO Tf i-( OS TP i-H CM lO i-H O CM lO CO t-OSCOOOOOCM 00 >-l O O O r* CM "* f- CM OS O^CMCMf- CM i-H CM CM CM < ) CM -^ -^ CM CO i Ol CM CM i-H CM CM • g oo«o sb ssaapj'Bq r^oj, CO lO CM i-H CO 00 00 CMHNiONCX) t^oooooot^r--i-~t- co oo r~- t^OOOOt^t^ 0000 00 J> CM i-l 00- CM ^ OS i-H t-- Tti N^^)i-*IOIO>0' 00 ti io io ■* CO lO CO •ainpi'BO d u fid d d r ^ d d "Ed dd ddddd^dfl ,H d d d^ddd dd 0H.2P000H oo.r^ooo ooooooo.S^ Hoo ooooo oo S WSSS SSMaSS §£££SW§K §§ §WSS£ §§ •uoji •joioo OOOOOOO OOOO ^O 0000000.-H OOO ooooo oo EH ONCN OONOIO OO OOOOOOO OOOOSOO O^-^OOOOI •l^ipiqmx OOOOOOO OOOOj^O OOOOOOOO OOO 0000£ oo CH H •8in^'Baadra8j J s w SB 5o r >T3 c6 JWfic ',0 cp-^^W H o^ > o curs o • mTS ° . o303^ .^jS • 3 S 3S S' • fe ° *E y <5h :d^ :°f !K^m, bX) PI o» w pq I < a W 9W ^ I W HObcHW PQ> H H « :w« ^,w^ %a , -^1 ^ oi ^j ^ t- oi cm ^EH Ol CM CQ lOCDcO ■^fH rH p» COCO, CO HI-* <" HH |' _I , : w I^oo^Phi-i c5Eh'^ . cv ,teH h" CM ^ oOCQCB .WWW w ^co 2W* lOOl 1^1 :cHen ss Hold cJ^tS u; CU , O) s>yZzl WW OcD^^ i PhPh'SS' W CO %&% Ph h whw pjpitf « r ^ WW PhP, ^2^' ^00 00 00 ri . . - ^OOOi-l » r/l r/i r/i t-- CO ee S^wgs w'^wg °4S : :w : : ° SJ o o^ o o T3 "S ^ ^ oS 'O "O q o : :g : : CfitC :o £« :u PP CHEMICAL CHARACTER OF WATER. 75 to O -*i o ■* O O O St*Ot>«5>OiO lo >o ON o 10 n o ■* IN ^ CM O 00 ■* CO CO N CON CD O MlOHH to . 1-1 r-i coco oq i-i co co OCOCS Tft 00 CO CMi-l §8 CO Sig (M CO cO OOOOOOOcO INH CO CO i-l CMCOCNCMCM CO 03 CO CM CM CM ■ ^■a-s *■&& ^^fte^ & vv •&* -Ste-Ste u.ow o O.S^.ShO o o 'W^ S ^WW SJsJHHSSS M SS W2 K£WS OOO OO O -O OO 'OOOO o oo oo oooo ooo OO ^fOO OOOOOOO O OCO oo oooo COIO^M • >0 ■ :B ; : : =i,o.2 ~ oo = .S S : : J •§ CO O Mo o o : 5Po O O 'O ^ =! & T3 ^ 'O ft 3.s J °3 R « cD^S gW 8 OS Kigali cicoP&HPn^S :2 aicd » CD P 55 £o %% W(^ c o O t-< .Ss 00 ' tJ ° WcO £wfc _£ioo COl^H *o oo cm i-H CO d dH . hHchH^OO HHP? oooo r ««§ 00 00 „ HHffi W W W w H W r fflffl0> 00?i H &H d£ . hWhHiOO s£ CM co 1 d CD (L, NCO ^1 H^ go CD CD Cx] CO CO CO CO M hHihH; CDh^*^ CD CD g^ M Hl4 H^_ A ^ Z 2 co co co co £ ?i coco £co ^coco?; o o ooo o«2 -O T3 T3 x) T3 T3 fl OX)^ NN NN 76 GEOLOGY AND WATERS OF GREAT FALLS REGION, MONT. WATER POWER. DESCRIPTION OF FALLS. The water power of the Great Falls region is undoubtedly one of its most valuable assets, although at present it is practically unde- veloped. Between the Great Northern Railway bridge at Great Falls and the mouth of Belt Creek, a distance of approximately 10 miles, Missouri River has a total fall of G12 feet. Of this amount the greater part occurs at five different places, Black Eagle, Coulters, Rainbow, Crooked, and Big falls, which are collectively known as the Great Falls of Missouri River. (See PL III, A, B, and PL IV, A, B.) The remainder of the fall which takes place between the above-mentioned points is in the form of rapids occurring at varying intervals between the cataracts. Conflicting reports are current re- garding the exact height of the different falls. According to the first measurements, which were made by Lewis and Clark in 1804, Black Eagle Falls have a drop of 20 feet, Coulters 14 feet 7 inches, Rainbow 47 feet 8 inches, Crooked 19 feet, and Big Falls 87 feet J inch. In M. S. Parker's description of the falls, published in 1894, the follow- ing measurements are given, which are somewhat at variance with those above quoted, although in a previous article by Parker, pub- lished in 1892, favorable comment is made on the accuracy of the Lewis and Clark measurement. Parker ascribes to Black Eagle Falls a drop of 20 feet, to Coulters 14 feet, to Rainbow 37 feet, to Crooked 19 feet, and to Big Falls 75 feet 4 inches. No careful meas- urements of these falls were made by the author while in the field, but according to the best information which can be obtained from local engineers familiar with the region the height of Black Eagle Falls, the first of the series, located at the Boston and Montana smelters, is 41 feet, including the masonry dam, which has been built on their crest. Coulters Falls, which are about 1 mile farther down- stream and just above the Great Northern Railway bridge, have a drop of 14 feet. A short distance below the railroad bridge and about one-eighth of a mile from Coulters Falls, are Rainbow Falls, which have a drop of 37 feet. Crooked Falls, so named from their irreg- ular shape, which occur about one-fourth of a mile farther down- stream, drop 20 feet, and 4 miles still farther down the Missouri the water at Big Falls plunges over a precipice 75 feet high. Views of Black Eagle, Rainbow, Crooked, and Big falls are shown in Pis. Ill, A, /?, and TV, A, /?, respectively. UTILIZATION. At present power from only Black Eagle Falls has been developed. The Boston and Montana Smelter Company have constructed a large masonry dam which develops sufficient power, supplemented by an WATER POWER. 77 auxiliary steam plant, to supply the large smelters owned by that company on the north side of Missouri Biver at this place. The amount of horsepower developed at Black Eagle Falls varies from 6,000 to 12,000, depending on the season. In addition to the large power plant located on the north side of the river there is also a smaller power plant on the south side, which is used as an electric station for power for street railways, electric-light plant, Royal Mill- ing Company's flour mills, and a number of smaller factories. UNDEVELOPED POWER. Coulters, Rainbow, Crooked, and Big falls are wholly undeveloped, although they are apparently more favorably situated for power development than Black Eagle Falls. The following table shows the available horsepower of the different falls : Available horsepower of the Great Falls of Missouri River. Name. Height. Discharge. Horsepower. Black Eagle Falls Feet. 41 14 37 20 75 Second-feet. 1,800 2,400 2,400 2,400 2,400 6,545 3 272 8,072 Crooked Falls 4,333 Big Falls 16, 363 38, 585 The above statements are based on a minimum flow of Missouri River above Black Eagle Falls of 1,800 second-feet, as shown by Government discharge measurements extending over a period of four years, from 1902 to 1905, inclusive. These measurements were taken at Cascade, where the Geological Survey has maintained a gaging station for a number of years. To the measurements of this gaging station is added an average minimum flow of Sun River, which empties into the Missouri a short distance above Great Falls and between Cascade and Black Eagle Falls. Below Black Eagle Falls Giant Springs add to the flow of the river approximately 600 cubic feet per second, which apparently does not vary at different seasons of the year. Taking this amount into consideration Coul- ters, Rainbow, Crooked, and Big falls would have a minimum flow of about 2,400 second-feet. This amount has been used for calculating the available horsepower at these cataracts. > Of course it should be borne in mind that by the proper development of any one of these falls the amount of available horsepower could be materially in- creased. It is possible also that by constructing suitable dams the fall of the numerous small rapids which occur between the cataracts could be made to furnish considerable power, but as such questions depend entirely on the nature and extent of the development, no esti- 78 GEOLOGY AND WATEKS OF GKEAT FALLS KEGION, MONT. mate as to the total horsepower which could be developed under ideal conditions of improvement in the vicinity of Great Falls is here given. IRRIGATION. GENERAL STATEMENTS. Irrigation has been practiced along the valleys of the larger streams in the Great Falls region for many years, but its growth and develop- ment have been necessarily slow until recently. Prior to the building of railroad lines into the district, which was in 1886, and for some time afterwards, the inhabitants of the region were principally en- gaged in cattle raising and mining, and only small tracts were irri- gated here and there along the valleys. With the growth in popula- tion and the increased demand for agricultural produce, irrigation began to be more generally practiced along the larger streams, result- ing eventually in the construction of several large canals by private individuals or small companies organized among the ranchmen. Extensive preparations are now being made, both by the Government and by private enterprises, to reclaim larger tracts of land along Sun and Teton rivers and the highland lying between these two streams. (See PL VII.) SUN RIVER VALLEY. Sun River valley is one of the most extensively irrigated valleys in the Great Falls region. There are a large number of small ditches covering the lower lands along each side of the river from the vicinity of Great Falls to the base of the Lewis Mountains. In addition to these several large canals have been constructed by individual ranch- men and small companies organized among the farmers. The largest of these is the Flowerree Trustee ditch, which is taken out of North Fork of Sun River near the center of sec. 20, T. 21 N., R. 6 W., and extends for about 25 miles eastward, covering a large territory of table-land bordering Sun River on the north. Another and some- what smaller ditch occurs on the same side of Sun River farther downstream, known as the Sun River canal. Its headgate is located near the east end of old Fort Shaw Reservation, and it furnishes water to an area nearly a mile in width, extending east as far as Muddy Creek of Sun River. One of the largest canals on the south side of Sun River is the Crown Butte canal, constructed by individual enterprise, which leaves the river in the southeast corner of sec. 6, T. 20 N., R. 4 W., and extending eastward crosses Sims Creek in a big loop, and passing through a low divide north of Crown Butte empties into the head of Little Muddy Creek valley. A number of smaller ditches are found along the south side of the river, including, from east to west, Campbell, Eder, and Richling Company, Bickel Burk, IRRIGATION. 79 Butler, Clemens, Phyllip, Mayer, and others farther up South Fork of Sun River. The Government irrigation project along the south side of Sun River, known as the Fort Shaw canal, covers about 16,000 acres in the vicinity of the Fort Shaw Reservation. The larger features of irrigation along Sun River valley are shown on the map (PL VII) . TETON RIVER VALLEY. Irrigation is not extensively practiced along the valley of Teton River in the vicinity of Chouteau. A few small farms are irrigated around Chouteau and near the head of Spring Creek, but, with these exceptions, irrigation is confined to Burton Bench, where a number of large canals have been constructed. Burton Bench, which is one of the largest, if not the largest, irrigation district in the area described, is supplied with water by three large canals, the Burton, Cooperative, and Eldorado canals. These canals are all taken from the Teton River 10 miles above Chouteau. Their approximate loca- tion and the land irrigated by them is shown on PL VII. The Cascade Land Company's ditch, which is taken out of Deep Creek on the south side about 3 miles above its mouth, extends around the east side of Priest Buttes, crosses by siphon flume the north end of Freezeout Basin, and continues to the Cascade Land Company's home ranch, where it furnishes water for several hun- dred acres of land situated in the southwestern part of T. 23 N., R. 3 W. A short distance below the headgates of the Cascade Land Company's ditch there is another ditch which is owned by the S. T. Cattle Company. It extends down the river about 6 miles, where it supplies Avater for over a thousand acres of land in T. 24 N., Rs. 3 and 4 W. The location of the above-described ditches and the approximate limits of the land to which they supply water are shown on PL VII. OTHER VALLEYS. Along the east side of Missouri River in the vicinity of Cascade, irrigation has been practiced for many years. No large canals have been constructed in this region, but a number of small ditches carry water some distance out from the river to scattered ranches along the valley. In Smith River valley are a number of irrigated ranches, but only a relatively small portion of the valley land is now culti- vated. Hound Creek, one of its principal tributaries from the west, has a few small irrigated ranches along its course. Considerable irrigation is carried on all along Belt and Otter Creek valleys. No large canals have been built along these streams, owing mainly to the fact that the valleys are narrow and the amount of irrigable land small. Short ditches which occur at frequent intervals supply 80 GEOLOGY AND WATEKS OF GREAT FALLS REGION, MONT. water to small fields. Throughout the eastern portion of the district the streams carry only a small flow of water, all of which has been appropriated for irrigation purposes. In some cases private reser- voirs have been constructed to increase the available supply by stor- ing flood waters. AGRICULTURE. Throughout the lower Plains portion of the Great Falls region the aridity of the climate renders tillage without irrigation impracticable, but in the plateau region bordering Little Belt and Highwood moun- tains dry farming is extensively practiced far up the slopes of these ranges. The cultivated portions of the area examined comprise a relatively small part of the entire district, the remainder being util- ized for pasturage of cattle — an important industry of the region, to which the upland areas are well adapted. Among the chief agri- cultural products are wheat, oats, barley, rye, spelt, flax, alfalfa, tame hay, potatoes, and a variety of garden vegetables, most of which are consumed by workers in the mines and smelters surrounding Great Falls. The main crop is wheat, which has a yield varying from 20 to 40 bushels per acre. Both winter and spring wheat is raised, but the preference seems to be for winter wheat at present. Oats have a large yield, ranging from 35 to 45 bushels per acre, and the yield of potatoes and other vegetables is unusually large. Cascade County, Mont., is one of the most important grain centers in the State. Fruit raising is a growing industry, and many young, well-kept orchards are to be found throughout the district ; currants, gooseberries, and strawberries are among the important fruits. The seasons are ordinarily of sufficient length to insure the maturity of all cultivated crops, except on the higher slopes bordering the inclosing mountain ranges, where the time between killing frosts is short. The distribution and extent of the land irrigated, also the area in which dry farming is practiced, are shown on PL VII. CLIMATE. TEMPERATURE. General statements. — The temperature records of this general re- gion present a very wide range between extremes — a feature which is apt to cause an erroneous impression. Though the annual range is probably as large as in any other part of the United States, the periods of low temperature are of short duration and are generally attended by dry, calm atmosphere. Under these conditions the low winter temperatures are not so severe on life in general as much higher temperatures would be under less favorable conditions. Owing to this fact stock can successfully winter on the range without shelter. The summer temperatures, although high, are not so oppressive as \\\\ equivalent temperature would be in more humid atmosphere in CLIMATE. 81 low altitudes. The summer days are long and often very hot, but as evening approaches the air cools rapidly by radiation, and the nights are cool and comfortable. Great Falls region. — Very few meteorological data are available regarding the mountainous districts surrounding the Great Falls region, but there are a number of places lower down on the plains where systematic observations have been carried on for a number of years. The first meteorological station was established at Chouteau in 1890, and in December of the following year a similar station was placed at Great Falls. The observations begun at Chouteau were continued for only one year, but the station was reestablished at this place in January, 1905. Climate data began to be collected in a systematic way at Sun Kiver in March, 1895, and a station was estab- lished at Augusta in July, 1896. Records of the temperature have been collected at Cascade, Mont., since May, 1891, but observations during the first two months are not quoted below. At Great Falls, where the most systematic information has been procured, and where the results are in a measure representative of the district, the mean monthly temperatures from 1893 to 1903, inclusive, are as follows : Mean monthly temperatures for ten years at Great Falls, Mont. °F. January 26 February 26 March 32 April 45 May 55 June 62 °F. July 68 August 67 September 56 October 49 November 33 December 30 Throughout the above-described period the mean of the maximum temperatures at Great Falls varied from 36° in January to 83° in July. The absolute maximum temperatures range from 60° in December to 106° in August, the mean of the minimum from — 11° in January to 51° in July, and the absolute minimum from — 38° in January to 35° in July. Although the climatic observations made at Great Falls may be regarded as in a measure representative of the district, yet for the purpose of comparing the variations between stations located near the base of the mountains and those farther out on the plains, the following comparative table is introduced. The highest tempera- ture ever recorded at the Great Falls station is 106°, which occurred in August, 1892. The minimum temperature recorded was — 38° in January, 1893. The average date of the first killing frost in autumn is in the latter part of September, while the average date of the last killing frost in spring is about the first of May. The direction of the prevailing wind is southwest, except in June, when it is west. 54572— irr 221—09 6 82 GEOLOGY AND WATEKS OF GREAT FALLS REGION, MONT. Comparative temperatures (°F.) at Augusta, Great Falls, Cascade, and Chouteau for five years (1902-1906, inclusive). Maximum. Minimum. Mean. 1902. 1903. 1904. 1905. 1906. 1902. 1903. 1904. 1905. 1906. 1902. 1903. 1904. 1905. 1906. January: Augusta Great Falls... 58 60 63 56 54 52 55 47 56 60 53 -30 -23 -14 - 2 -10 - 7 -28 -21 -21 -26 -24 -28 -21 -14 -10 - 9 -10 -35 -24 -31 -28 14 25 20 22 19 30 28 22 30 40 37 35 38 45 48 38 31 44 38 39 23.9 27.6 31.0 31.8 27.4 29.4 18.2 18.2 19.4 28.2 29.2 61 63 55 60 63 70 68 72 71 86 82 86 85 85 87 88 90 82 80 85 80 88 92 98 94 93 96 94 97 28.5 February: Augusta Great Falls... 58 60 55 55 54 52 65 62 63 64 70 71 75 69 73 74 76 72 78 78 82 81 83 88 88 84 91 93 95 98 89 93 96 95 85 86 -19 -16 -21 -18 -20 -16 -43 -30 -38 -34 - 7 9 1 6 4 19 14 11 26 31 28 25 30 35 33 31 31 48 44 34 31 42 40 35 27 32 26.6 27.5 24.0 25.9 15.8 15.1 18.6 20.2 22.3 19.9 37.0 40.8 42.0 37.8 41.2 44.6 45.5 41.6 46.6 50.6 51.3 47.2 53.8 58.0 58.4 55.6 67 68.4 68.5 65.3 62.9 70.2 70.2 65.6 55.1 59.6 29.2 30.1 33.0 30.0 March : Augusta Great Falls... 55 56 62 63 58 45 -16 - 6 -13 - 7 -21 -13 29.2 35.0 25.7 27.2 22.8 16.6 23.2 26.2 27.2 24.3 April: Augusta Great Falls... 66 68 72 72 79 72 15 20 10 20 16 20 39.8 43.7 39.5 43.8 44.8 48.2 45.6 49.0 50.8 47.4 May: Augusta Great Falls... 86 86 84 89 77 82 25 30 24 27 20 30 50.8 56.2 47.2 51.0 49.5 54.2 46.6 50.1 51.0 48.6 June: Augusta Great Falls... Cascade 83 86 86 87 90 94 27 34 32 40 32 41 53.2 57.4 60.0 65.0 56.4 62.0 53.0 57.7 59.4 55.4 July: Augusta Great Falls... 87 92 93 92 "97" 99 36 42 34 42 "48" 41 59.9 65.4 60.0 65.6 '69.' 5" 68.6 63.4 69.8 71.4 66.4 August : Augusta Great Falls... Cascade 86 89 92 94 91 86 100 35 43 32 42 31 17 35 61.1 67.0 60.3 65.5 60.8 53.6 67.4 60.2 65.4 63.4 62.5 September: Augusta Great Falls... 83 83 80 80 88 90 95 23 28 20 30 19 30 26 49.9 56.7 50.6 56.1 55.6 57.8 60.4 Chouteau ... 87 78 77 85 78 74 64 69 75 56 51 27 - 2 2 3 - 4 -28 -18 -21 -24 -10 -16 57.2 40.6 41.0 45.0 40.6 35 36.7 October: Augusta Great Falls... 80 77 80 78 81 80 86 19 22 20 25 11 28 22 45.8 48-8 48.8 51.8 47.8 50.6 48.4 November: Augusta Great Falls... 54 58 72 70 74 65 66 - 2 6 -39 -25 10 17 13 28.9 32.6 27.0 31.6 43.0 45.8 47.6 37.1 32 31.4 December: Augusta Great Falls... Cascade 52 52 61 56 60 54 67 -17 -10 -14 -12 -26 -20 -24 24.2 23.6 33.0 33.8 29.7 31.4 33.3 Chouteau 58 - 9 33.0 RAINFALL. There is only a moderate amount of rainfall throughout the Great Falls region, especially in that portion bordering the adjacent moun- tain ranges. On the lower lands farther out on the plains more arid conditions prevail. A characteristic of the annual precipitation in this legion, as in other parts of Montana, is that a large percentage falls during the growing season. The amount of rainfall received during the four summer months nearly equals that for the remainder CLIMATE. 83 of the year — a feature peculiarly favorable for agriculture. The mean monthly precipitation at Great Falls for a period of ten years, 1893 to 1903, inclusive, is as follows: Mean monthly precipitation at Great Falls, Mont. January 0. 6 February .5 March .7 April 1. 2 May 2. 6 June 2.8 July August September October __. November . December . During the period of ten years above described the total rainfall for the driest year was 6.7 inches, while the total for the wettest year was 17.3 inches. The average depth of snow for this period is 39.6 inches, and the heaviest snowfall in twenty-four hours is 9.3 inches. In order to show the relative precipitation of the regions adjacent *^to the mountains and those farther out on the plains, the following comparative table is introduced; Relative precipitation at Augusta, Great Falls, Cascade, and Chouteau for five years (1902-1906, inclusive) . Rain and snow (melted) . Snow. 1902. 1903. 1904. 1905. 1906. 1902. 1903. 1904. 1905. 1903. January: Augusta Great Falls. 0.14 .16 0.19 .08 0.21 .17 0.40 .32 .23 0.51 .32 .20 .12 .45 .77 .85 .08 .70 .73 .63 .31 3.3 1.6 1.5 .7 2.5 1.7 4.0 5.0 Cascade 4.5 7.1 Chouteau February: Augusta .49 1.02 .18 .35 .15 .51 .40 .17 .31 .12 2.27 .66 ,55 -56 1.78 .68 .84 -55 1.52 1.99 2.30 1.45 4.97 4.23 5.48 2.63 1.70 .67 1.04 1.25 1.44 .82 2.05 .70 8.2 2.0 9. 8 3. 5 1.0 4.9 4.0 4.5 Great Falls Cascade 9.0 2.4 1.5 10.0 Chouteau Tr. March: Augusta Great Falls .76 .19 1.00 .89 2.18 2.20 14.0 1.6 10.0 8.0 18.0 22.0 7.0 Cascade 8.5 4.6 10.0 "ii.'s" 9.1 Chouteau April: Augusta .35 .05 1.71 2.00 .50 .62 .92 1.17 1.16 .56 6.43 5.03 5.79 4.47 .97 5.59 2.69 1.57 1.00 .88 .80 1.14 2.18 2.66 3.15 2.75 13.0 1.5 Tr. Great Falls Tr. Cascade Chouteau . May: Augusta . . . 4.16 5.93 2.48 1.84 .92 1.16 2.5 8.0 6.0 Great Falls. Tr. Tr. 2.0 Cascade .1 Chouteau June: Augusta .79 4.02 1.36 2.19 .99 1.06 Great Falls Cascade Chouteau July: Augusta 3.54 2.74 "".'97' 29 | Great Falls 2.14 Cascade. . Chouteau August: Augusta .77 .55 1.51 •74 .32 1-18 .12 | ■ Great Falls Cascade Chouteau a A portion of the data above and in the statements immediately following are for the period from 1893 to 1903. The remainder is computed from the establishment of the station in 1891. 84 GEOLOGY AND WATERS OP GREAT FALLS REGION, MONT. Relative precipitation at Augusta, Great Falls, Cascade, etc. — Continued. Rain and snow (melted.). Snow. 1902. 1903. 1904. 1905. 1906. 1902. 1903. 1904. 1905. j 1906. September: Augusta .36 .74 .75 .99 .16 .14 .13 .07 .18 Great Falls Tr. i Cascade Chouteau .27 .47 .26 .38 .10 .60 1.25 1.50 .26 .10 .18 .20 Tr. October: Tr. .07 .27 .45 .10 .44 .29 2.2 Tr. 1.0 Tr. Tr. 5 Great Falls Cascade 4.0 Chouteau November: .32 .45 1.71 .83 Tr. .01 .02 16.0 8.3 Tr. 6 Great Falls Cascade 10.3 Chouteau December: 1.00 .39 .69 .91 .40 .54 .38 6.0 9.1 4.0 8.0 1.0 1.8 2.0 Tr. Great Falls Cascade Chouteau CULTURE. Settlement here as elsewhere is determined by geologic and cli- matic conditions. Along all the larger stream valleys where surface water for irrigation purposes is available settlements are numerous, but much of the upland and grazing districts is thinly populated. On the higher slopes bordering the mountains in the zone of in- creased rainfall many small farms occur, some of which are among the best improved places found in the district. One relatively large town, three medium-sized coal-mining towns, and a number of smaller trading points are in the district. Great Falls, a town of 18,000 inhabitants and a thriving business center, is located on Missouri River near the north-central portion of the district. Although at present none of its railroad lines are trans- continental, they are the most important connecting lines between the main lines of the Great Northern and the Northern Pacific, and when the Billings and Northern road, now being constructed between Billings and Great Falls, is completed it will open up a new trans- continental route through Great Falls to the northwest coast. At present railroad lines extend in four directions from Great Falls: The Great Northern southwestward to Helena and Butte; the Mon- tana and Great Northern northwestward to Shelby Junction, a point on the main line of the Great Northern ; the Great Northern extend- ing northeastward to Havre, another point on the Great Northern main line ; and the Neihart branch of the Great Northern connecting Great Falls with Neihart, a silver-mining town in the Little Belt Mountains about 100 miles to the southeast. This road has a short branch line leaving it at Gerber station for Stockett and Sand Coulee, two of the larger coal-mining camps. The Boston and Montana Consolidated Copper and Silver Mining Company's smelters and CULTURE. 85 refineries are located at Great Falls; also the Eoyal Milling Com- pany, besides a number of smaller business enterprises. The ore handled at the smelters comes from Butte and Anaconda; this, to- gether with the coal and limestone used in the operation of the plant, makes a relatively large freight traffic for Great Falls, while it also furnishes employment for a large force of men. Belt, one of the largest coal-mining towns in the region, has a population of about 1,000, composed mainly of employees of the Anaconda Copper Mining Company, the largest operators at this place. It is located on Belt Creek, about 20 miles southeast of Great Falls, on the Neihart branch of the Great Northern road, and is the oldest coal-mining town in this region. About 10 miles west of Belt and about 10 miles from Great Falls are the two coal-mining towns of Stockett and Sand Coulee. At Stockett, the larger of the two places, is located the Cottonwood Coal Company, which is one of the two largest coal-mining companies operating in the district. Stockett has a population of about 800, composed largely of coal miners employed by the Cottonwood Coal Company. Sand Coulee, about 2|- miles northwest of Stockett, is a smaller mining town of about 400 inhabitants. It is situated in Straight Coulee, a branch of Sand Coulee, and owes its existence mainly to the Nelson and Gerber coal companies, which are operating at this place. The other towns in the district are mainly supported by a ranch population. Chouteau, the most important of these and the county seat of Teton County, is located on Teton River, about 40 miles northwest of Great Falls. It has a population of about 400, and is bordered on the north by one of the oldest and best-developed irri- gated districts in the Great Falls region. Along Sun River there are a number of small towns and trading- points. The largest of these is Augusta, in Lewis and Clark County, on South* Fork of Sun River, about 3 miles above its mouth. Sun River, somewhat smaller, although one of the oldest towns in this region, "is located in Sun River Valley, about 20 miles west of Great Falls. Two towns have recently been laid out in Sun River valley by the Reclamation Service engineers — one at Fort Shaw Indian School, which will be known as Shaw, and another at the mouth of Sims Creek, which is called Sims. At Flowerree home ranch there is a large company store and another at Sunnyside, owned by the Sun River Stock and Land Company. Along the Great Northern Railway line the prin- cipal town within the area described is Collins, located on the north side of Teton River. From this place stage lines connect with Chou- teau through Farmington, a post-office and store in the middle of Burton Bench. Bynum, another small trading point, is located in the northwest part of Burton Bench. 86 GEOLOGY AND WATEES OF GEEAT EALLS EEGION, MONT. There are no towns along Missouri River below Great Falls within the area described, but above that town are Wo small stations, Ulm and Cascade, the latter, located near the base of the Big Belt Moun- tains, with a population of about 200. It is supported by a large ranch trade from each side of the river. On Smith River there is a post-office known as Truly, about 5 miles above its mouth ; another, Orr, farther up the river, has recently been discontinued. In Belt Creek valley, about 2 miles above Belt, is the small town of Armington, which is situated at the junction of the new Billings and Northern and the Neihart branch of the Great Northern. It is mainly a small railroad town, which receives a portion of the ranch trade of the surrounding country. Along the new railroad there are a few small stores, located at intervals of 12 to 15 miles ; these are Spion Kop, Geyser, and Stanford, the latter being an important trading point for a large ranch district along Skull, Running Wolf, and Sage Creek valleys. While the Great Falls region is at present a sparsely settled dis- trict, it is believed that the Government irrigation projects now under way which will reclaim millions of acres of fertile farming land, the almost unparalleled advantages for the development of water powder, and the increasing railroad facilities will cause the population to increase rapidly within the next decade. INDEX. Agriculture, condition of Alluvium, character and distribution of water in Altitudes, statement of Anaconda Consolidated Copper and Mining Co., smelters of, view of Armington, description of Arrow Creek, description of Artesian wells, data on distribution of Augusta, description of rainfall at springs near temperature at water of, analyses of wells near Belt, description of rocks at water of, analyses of well near Belt Creek, description of 11, flow of rocks on 17-18, section on springs on view of Benton Lake, description of Big Belt Range, structure of Big Falls, description of view of Black Eagle Falls, development at 8, description of view of Box Elder Creek, flow of wells on Burton Bench, description of lakes on springs on water of, quality of wells on 39, Bynum, location of Calvert, W. R., work of Carboniferous rocks, character and distribu- tion of Cascade, description of flow at irrigation near springs near rainfall at temperature at wells near Cascade formation, correlation of 18, Castle limestone, occurrence of Chief Mountain, fault at Page. 80 j 15,26 26 I 10-12 ! 28 86 34 58-59 60-61 85 83-84 37,42 82 73 51,65 85 21 74-75 59 32-33 33 19,21 19 36 12 34 27-28 76-77 30 76-77 76-77 28 33 63 13,67 34-35 36 72 67-68 85 16-20 86 29 79-80 43 83-84 82 52 20-21 17 27 Page. Chouteau, description of 85 irrigation near 79 rainfall at 83-84 springs near 36, 42 temperature at 82 water supply of 70 analysis of 73 wells near 50-51, 67 Claggett formation, character and distribu- tion of 15, 23-24 section of 24 water of 24, 66 Climate, data on 80-84 Collins, description of 85 Colorado formation, character and distribu- tion of 15, 22-23 spring from, view of 36 water in 23, 35, 64, 65, 66, 72 Cora, water of, analysis of 74 Coulters Falls, description of 76-77 Cretaceous rocks, character and distribution of 15-16, 20-24 Crooked Falls, description of 76-77 view of 30 Crown Butte, description of 12 rocks of " 23. Culture, description of 84-86 Deep Creek valley, wells in 67 Dinosaurs, discovery of 18-19 Drainage, description of 11-14, 28-34 Drilling, method of 68 Dutton, wells near 39, 51, 66 wells near, record of 41 Eagle formation, character and distribution of .- 15,23 view of 12 water in 23, 35, 36, 65, 66 Eakin, H. M., work of 8 Ellis formation, character and distribution of 16,18 water of 18 Farmington, wells near 58-59 Faults, occurrence and character of 27-28 Fort Benton, rocks at 22 Fort Benton Bench, description of 66-67 wells in 66-67 Fort Shaw, springs near 36 well at 65 Fort Shaw Butte, description of 12 rocks of 23 springs at 36 Freezeout Basin, description of 13 Freezeout Bench, description of 66 wells in 66 87 88 INDEX. Page. Freezeout Lake, description of 13, 34 springs near 66 French, John, work of 8 Geography, description of 10-14 Geology, account of 14-28 Geyser, location of 86 springs near 47-49 water of, analyses of 75 wells near 57, 61-62 Geyser Creek, rocks on 19 Giant Springs, description of 37 flow of 37 analysis of 38 source of 38-39 view of 36 Gilmore, C. H., on dinosaur fossils 18 Girty, G. H., fossils determined by 17 Glacial deposits, character and distribution of 15, 25-26 water in 26' Gravels, character and distribution of 15, 24-25 water in 25 Great Falls (town), description of 84-85 irrigation near 78-79 map of 36 rainfall at 83-84 rocks near 22 springs near 43-44, 63-64 temperature at 81-82 water powers at 76-77 water supply of 69-70 analysis of 70, 73, 74 wells near 39, 53-55, 59, 63-64 records of 39-41 Hazlett Creek, rocks on 19 Hepler, springs near 42 water of, analyses of 73 wells near 51 Highwoods Mountains, description of 10 structure of 27 Irrigation, status of 78-80 Jurassic rocks, character and distribution of . 16 Keewatin ice sheet, extent of 25 Kibbey sandstone, occurrence of 18 Kootenai formation, character and distribu- tion of 15,20-22 section of 21 water in 22,35,64,71 Laccoliths, occurrence and character of 27 Lake deposits, occurrence and character of. . . 15, 26 Lakes, description of 34-35 Lewis, Meriwether, on Great Falls region 8 Lewis Range, structure of 27-28 Literature, list of 8-10 Little Belt Mountains, description of 10-11 structure of 27 Little Otter Creek, location of 10 rocks on 17 Lonetree Creek, artesian water on 62 Lowry, springs near 36 Madison formation, character and distribu- tion of 16,17 water in, absence of 18 Map, geologic, of region Pocket. Ming Coulee, description of 12 rocks on 17, 19 Page. Missouri River, description of 28-29 falls of ' 28 views of 28, 30 flow of 11, 29-30 old channel of 25 springs on 37, 64 water powers on 76 wells on 64 Montana group, character and distribution of 15,23-24 water in • 72 Moraines. See Glacial deposits. Morrison formation, character and distribu- tion of 15, 18-19 section of 19 water of 19 Mortson, O. C, work of 8 Muddy Creek, artesian water on 61, 68-69 artesian water on, quality of 72 source of 69 springs on 36 Orr, location of 86 Otter Creek, description of. .... . 33 rocks on 19 springs on 35, 36, 63 wells on 63 Otter Creek divide, description of 10 Paine shale, occurrence of 17 Plains province, description of 10-11 Priest Buttes, description of 13 Priest Lakes, description of 34 Quadrant formation, character and distri- bution of 16, 17-18 water of 18, 72 Quaternary deposits, character and distri- bution of 15, 24-26 Railroads, distribution of 84 Rainbow Falls, description of 76-77 view of 28 Rainfall, data on 82-84 Red Buttes, rocks of 22 Riceville, rocks on 17-18 Robbins, S. B., work of 8 Running Wolf Creek, description of 34 rocks on 19 Sage Creek, artesian water on 62 rocks on 19 Sand Coulee, description of 12, 33-34 rocks on 17, 19 springs on 36 wells in : 63-64 Sand Coulee (town), water supply of 70, 71 water supply of, analysis of 74 Shaw, founding of 85 Sims, founding of 85 Skull Butte, description of 12 rocks of 17, 21 section at 21 Skull Creek, artesian water on 62 rocks on 19 Smith River, description of 11, 31 flow of 31 irrigation near 79 rocks on 19, 22, 23 springs on 36 wells near 64 INDEX. 89 Page. Spanish Coulee, fossils in 20 Spion Kop, location of 8G Springs, occurrence and character of 18, 35-39 view of 36 Square Butte, rocks of 23 springs at 36 view of 12 Stanford, description of 86 springs near 49-50 water of, analysis of 75 wells near 57-58, 59 Stanford Buttes, description of 11 Stockett, rocks on ' 17 springs near 44-47 watersupply of 70-71 wells in and near 55-57, 63-64, 70 analysis of 74 Stratigraphy, account of 14-26 Streams, description of 11-14, 28-34 Structure, description of 26-28 Sun River, description of 11, 30 flow of 30 irrigation on 78-79 section on 24 springs on 36, 42 wells near 51, 61, 65-66 water of, analyses of 72 quality of 73 Sun River (town), description of 85 Surface waters, description of 11-14, 21-35 Surprise Creek, description of 34 rocks on 19 Swamps, description of 34-35 Temperature, data on 80-82 Terrace deposits, character and distribution of 24-25 Page. Terrace deposits, water in 25 Tertiary deposits, character and distribution of -15 Teton Buttes, location of 13 Teton River, description of 11, 31-32 flowof 32 irrigation on 79-80 springs on 36 water of, quality of 72 wells near 66-67 Towns, water supply of 69-71 Truly, location of 86 springs near 43 wells near 52-53 Ulm, location of 86 Ulm Bench, description of 12 rocks of 23 wells on 64-65 Underground waters, chemical character of. . 71-75 description of 35-75 description of, by districts 61-69 Villages, water supply of 69-71 Water, analyses of 73-76 Water powers, description of 76-78 Water resources, chemical character of 71-76 description of ...... '. 28, 78 development of 71 source of 28 Waters, underground. See Underground wa- ters. Wells, distribution of 39 list of and data on 42-59 records of 39-41 Winchester, R. D., work of 8 Wolf Butte, location of 12" Woodhurst limestone, occurrence of 17 o 54572— irr 221—09- * I