GLACIERS OF 
 GLACIER NATIONAL PARK 
 
 
 
 
 
 - *•. • 
 
 
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 DEPARTMENT OF THE INTERIOR 
 OFFICE OF THE SECRETARY 
 1914 
 
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 GLACIERS OF GLACIER NATIONAL PARK . 1 
 
 By Wm. C. Alden, U. S. Geological Survey. 
 
 INTRODUCTION. 
 
 Glacier National Park derives its name and much of its interest 
 from the presence of many small glaciers. Very much of the grandeur 
 of its wonderful Alpine scenery, the final sculpturing of the great 
 mountain valleys and of the amphitheaters at their heads, and the 
 production of the basins of its many beautiful lakes are due to the 
 action of the more extended glaciers of the past. 
 
 There are in the park about 90 small glaciers ranging in size from 
 Blackfeet Glacier, with its 3 square miles of ice, down to masses but a 
 few acres in extent Vet exhibiting the characteristics of true glaciers. 
 The most easily accessible of these from the beaten trails are the 
 Blackfeet and Sperry Glaciers and the small glaciers at Iceberg Lake 
 and at Ahern Pass. Some of the others can be reached bv tourists 
 who are willing to undergo the exertions of mountain climbing. 
 Among these are Grinnell, Chaney, Shepard, Vulture, and Carter 
 Glaciers, and one or two at Brown Pass. (See map facing page 17.) 
 
 After examining these features one can easily picture to himself, as 
 he looks down the valleys, the great rivers of ice which in ages past 
 cascaded from the cliffs below the upper cirques, converged as 
 tributaries from the many branch valleys, and united in great trunk 
 glaciers. In imagination he can see these great glaciers many 
 hundreds of feet in depth filling the great mountain valleys from side 
 to side, and deploying thence upon the bordering plains. He seems 
 to see these mighty engines plucking away the rock ribs of the moun¬ 
 tains, smoothing, grinding, and polishing the irregularities and sweeping 
 away the debris to be spread on the plains below. These glaciers 
 developed and extended three times and, after each development, 
 the congealed masses melted away on the return of milder climatic 
 conditions, until at length only the small cliff glaciers of the present 
 
 1 The descriptions of the glaciers and the discussion of the glacial phenomena presented in this paper are 
 based upon studies by the writer, made during the summers of 1911, 1912, and 1913 for the United States 
 Geological Survey, in and adjacent to the park. He was assisted in 1911 by J. Elmer Thomas; in 1912 by 
 Eugene Stebinger, and in 1913 by Clifton S. Corbett. Not all of the pricipal glaciers have been examined 
 and much of the area of the park remains to be covered by the geological survey. The presentation in this 
 paper is thus only preliminary in character and is intended rather as a popular than a technical discussion. 
 
 For further treatment of the physiographic development of the region one should refer to the companion 
 pamphlet issued by the Department of the Interior, entitled “ Origin of the scenic features of Glacier National 
 Park, Montana,” by M. R. Campbell. This publication may be purchased from the Superintendent of 
 Documents, Government Printing Office, Washington, D. C., for 15 cents. 
 
 3 
 
4 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 day are left lurking in the protected recesses at the heads of the capa¬ 
 cious valleys. 
 
 Many of the rock-walled amphitheaters are no longer occupied by 
 ice, but from all there issue streams fed by the melting snow or ice. 
 These plunge over the cliffs in beautiful foaming cascades and rush 
 on down the mountain gorges. The melting glaciers left many 
 inclosed basins large and small, and in these the waters rest a while 
 and mirror in their crystal depths the dark green of the surrounding 
 forests, the rich colors of the rugged mountain walls, and the deep 
 blue of the cloud-flecked sky. On again from lake to lake the waters 
 flow and finally start down their long courses to the sea to merge at 
 length with the chill waters of Hudson Bay, the balmy tides of the 
 Gulf of Mexico, or the rolling billows of the Pacific. 
 
 Compared in size with the great glaciers of Alaska the glaciers of 
 Glacier National Park are insignificant. They are even surpassed 
 in size by those of the Alps, of the Canadian Rockies, and of Mount 
 Rainier, Washington. They are, however, though small, among the 
 best examples of this interesting type of phenomena now existing in 
 the United States. They have also a splendid setting in magnificent 
 Alpine scenery, unsurpassed hi grandeur anywhere. Hidden away 
 in the recesses of the mighty mountain ranges these rare and won¬ 
 derful features form a climax to many of the interesting trips open 
 to the tourist. 
 
 BLACKFEET GLACIER. 
 
 General relations .—The largest glacier of the park, one of the most 
 readily accessible, and one exhibiting hi fine development most of the 
 features particularly characterizing glaciers is the Blackfeet 1 (title- 
 page and fig. 13, p. 24). 
 
 From Gunsiglit Camp, an easy trail leads southward about 1 mile, 
 with an ascent of about 500 feet, to the foot of the main lobe of the 
 western part of the glacier. Climbing the morainal embankment 
 which obstructs the view one looks out on a scene of surpassing 
 interest and grandeur. The distance across the glacier on a nearly 
 east-west line, is 3.2 miles; the maximum extent southward from the 
 front of the eastern lobe to the crest of the snow-covered Continental 
 Divide on Blackfoot Mountain is 1.6 miles; the distance from the 
 front of the western lobe to the divide southeast of Jackson Mountain 
 is nearly the same; the approximate area of the entire mass H3 square 
 miles. Lying in a depression in the mountain slope, having a greater 
 extent laterally than in the direction of movement, and having no 
 lobate extension down the valley, it is what is known as a cliff glacier. 
 
 i In an article in the Scientific American Supplement, Sept. 23, 1899, George B. Grinnell states that in 
 1891 he took to the head of St. Mary River the first party that had ever visited it so far as known. In 1895 
 in company with a Government commission he again visited the head of the valley. In 1897, in company 
 with J. B. Monroe, he climbed Jackson Mountain, and in 1898 he ascended Blackfoot Mountain and from 
 it beheld the glacier to the south which had been seen in 1883 by Prof. Raphael Pumpelly on a trip across 
 Cut Bank Pass and which since that time has been known as Pumpelly Glacier. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 5 
 
 Banked against the upper mountain slopes is the snow field, or 
 neve, from which the glacier originates. Here what is left of the snows 
 of many* winters has become compacted and changed to granular ice. 
 When such ice accumulates to a sufficient thickness internal move¬ 
 ment begins. Such moving ice constitutes a glacier. High up on 
 the slopes there may be seen, in places, a line of crevasses which 
 marks a break between the moving ice and the stationary part of 
 the neve. Such a crevasse is called the “ bergschrund ” by the 
 Germans. The mam or eastern part of the glacier nearly fills the 
 upper cirque extending almost to the crest of the cliff at the head of 
 the valley southwest of Citadel Mountain. Beneath the western part 
 of the glacier the slope nearly coincides with the inclination of the 
 rock and there is no marked break forming a cliff. 
 
 Moving down this slope, the ice of the western part of the glacier 
 gathers in from all sides to a central stream. The lower 0.7 of a mile 
 of its extent is thus contracted to a narrow lobe about 1,600 feet in 
 width. This part is easily accessible to the tourist and here may 
 be observed most of the typical characteristics of alpine glaciation. 
 7’ Moraines .—Along the front of the glacier throughout nearly its 
 whole extent is a great embankment or moraine of clay and bowlders 
 which was formed by the piling up of rock debris carried forward by 
 the moving ice. The greater part of such material, which is known 
 as drift, is embedded in the lower part of the ice when being trans¬ 
 ported, but a smaller part is borne upon its surface, having fallen 
 from the mountain slopes. When released by melting at the glacial 
 front the drift accumulates and may be crowded up into a ridge. 
 Much of the morainal material piled up along the front of the Black- 
 feet Glacier probably accumulated some time ago when the ice was 
 thicker and somewhat more extensive. A person standing on the 
 moraine where it is most readily accessible from the trail sees the 
 main lobe of the western part of the glacier extending down between 
 two great morainal embankments. The glacier thins to a frontal 
 margin at an elevation of about 5,725 feet above sea level. The 
 moraines, however, continue some distance farther down the slope 
 and there they curve together and join in one continuous loop, show¬ 
 ing that at some earlier date this lobe had a somewhat greater exten¬ 
 sion. The distance from the end of the morainal loop to the front of 
 the ice was not measured, but it is estimated as about 1,000 feet. 
 Across the end of the loop trees are growing, but nearer the ice there 
 is no vegetation and the bare slopes are very steep and in places 
 even precipitous as the result of slumping and sliding of the clay and 
 bowlders. The moraine ranges in height from 20 to 100 feet with an 
 uneven, ridged crest varying from a few feet to a few yards hi width, so 
 that it is a striking topographic feature. For some distance from the 
 lower end of the ice lobe the northwest margin has been melted back 
 50 to 100 yards, from the foot of the inner slope of the moraine, expos- 
 
6 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 ing the bare, smoothly polished, and striated ledges of rock over 
 which the ice formerly extended. Farther west up the slope the thin 
 ice extends to the foot of the moraine. On the east side of the lobe 
 the ice extends to the foot of the moraine but the crest of the latter 
 towers high above it. 
 
 Movement .—That the ice is not stagnant but moving slowly forward 
 may be easily demonstrated. Opposite the sharp curve in the moraine 
 at about 6,350 feet above tide there is a change in the slope. Looking 
 into a low ice cave at this place one can see far under the glacier. 
 Here the ice after passing the crest of the ledge extends free a few 
 feet above the rock over an area of many square rods before breaking 
 down. An iron spike set in the ice at this place on August 19, 1913, 
 showed a movement of 3| inches in the first 24 hours, of three-eighths 
 inch in the next 5 hours, and of 3| inches in the succeeding 25 hours 
 and 25 minutes. This gives an advance of 7 inches in 54 hours and 
 25 minutes. 
 
 Owing to the steepening of the slope at this place the ice is much 
 crevassed. Some distance farther up the slope is another broad 
 zone hi which the ice is much broken by crevasses. A second spike 
 set in the ice wall of a cavity at a point N. 85° W. of the peak of 
 Jackson Mountain and about 6,725 feet above tide near the lower 
 border of the upper crevassed zone, showed an advance of 1J inches 
 hi 24 hours, and in the succeeding 30 minutes an additional advance 
 of one-eiglitli inch, the time behig in the middle of a warm, bright 
 day. 
 
 On August 21, a marked pebble was set in the ice at a point hi 
 front of the glacier N. 75° E. of the peak of Jackson Mountain and 
 six-tenths of a mile northeast of the 6,879-foot bench mark. The ice 
 at this pohit advanced seven-eighths inch in 4f hours during the warm 
 part of a warm day. 
 
 This is a crude method of measuring the rate of movement, and the 
 results can not be regarded as a true index of the rate hi all parts of 
 the glacier. No attempt has yet been made to obtahi accurate 
 measurements of the movement in this or any other glacier within 
 the park, and no estimate of the total yearly advance can be made 
 from measurements as few and so crude as these. The rate of glacial 
 movement varies greatly with temperature and other climatic condi¬ 
 tions, being more rapid on warm moist days than on cold and dry 
 days. 1 
 
 Crevasses and ice cascades .—Ice has little elasticity, so that crevasses 
 are produced in the surface of a glacier by tension at places beneath 
 which are considerable irregularities or steepenings of the rock slope 
 down which the ice is moving. As the broken ice moves slowly forward 
 
 1 The rates of average daily movement of glaciers in the Canadian Rockies and Selkirks range from 2 
 to 20 inches, of the great Alaskan glaciers 1 to several feet, as much as 7 feet on Muir Glacier. In the Swiss 
 Alps the rates range from 1 or 2 inches to 4 feet or more per day. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 7 
 
 a succession of fractures constantly takes place in the same relative 
 positions. There is a regular cycle in the development of crevasses 
 which is well illustrated in the upper crevassed zone on the west¬ 
 ern part of Blackfeet Glacier (title-page). In the upper part of the 
 central belt the cracks appear; farther down the widening of the 
 cracks by melting breaks the surface into flat-topped tables. As the 
 crevasses gradually widen the intervening tables narrow until they 
 become sharp-crested ridges where one can scarcely find footing. Fol¬ 
 lowing this the sharp ridges may be broken into pinnacles or seracs, 
 such as may be seen at one place near the ice front south of Citadel 
 Mountain. Finally the ridges are lowered by the melting and gradu¬ 
 ally disappear. With the closing of the crevasses below, the surface of 
 the glacier thus becomes again smooth and passable. Crevasses are also 
 sometimes healed by being filled with snow or by the freezing of water 
 which may accumulate in them when the bottoms are tightly closed. 
 From the latter result the ice dikes seen on some of the other glaciers. 
 
 These crevasses are dangerous pitfalls in the way of the tourist, 
 even when not treacherously hidden by a slight covering of snow. 
 With competent guides and care, however, the less fractured parts of 
 the glacier may be traversed in safety. 
 
 At many points on the higher slopes the snow and ice may be seen 
 cascading over the ledges. Here the ice is greatly crevassed and 
 broken and great masses stand ready to fall, especially on warm days. 
 Such cascades, though very attractive, are dangerous to approach. 
 On the slope of Blackfoot Mountain (fig. 13, p. 24), where a great 
 ledge intervenes, the continuity of the cascade is broken for some 
 distance by a cliff of bare rock, above which rises a cliff of ice. Here 
 the ice, which is pushed forward above the cliff, may break off and 
 drop to the glacier below, there to be welded by refreezing into the 
 continuous sheet. 
 
 Structure .—The ice composing a glacier is generally stratified in 
 layers as a result of the conditions of original deposition. This struc¬ 
 ture may be indicated by more or less definite dirt zones extending in 
 parallel curving lines across the surface of the glaciers. As the layer 
 of snow which accumulates during one winter is gradually thinned or 
 melted away during the succeeding summer, dust and small rock 
 fragments which have fallen upon it become concentrated in a thin 
 but fairly definite layer. This is later buried beneath the clean 
 snows of the following winter. When compacted to glacier ice, there¬ 
 fore, there are apt to be thin layers of somewhat dirty ice alternating 
 with thicker clean layers. In places where the surface of the snow 
 docs not become soiled by rock debris, melting may cause the forma¬ 
 tion of a crust of nearly clear ice which, when buried by later snows, 
 appears as a blue band. The thicker intervening layers appear white 
 because the unfilled air spaces between the ice granules permit reflec¬ 
 tion of light from the myriad surfaces. The beautiful banded 
 
8 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 structure of alternating blue and white ice may be seen in the sides 
 of the crevasses. As the glacier is thinned by melting, these layers 
 outcrop as zones in the frontal slope. They correspond, in a way, to 
 the annular rings in the growth of a tree. 
 
 Drainage .—During the cool nights and early mornings there is 
 little sound of water on a glacier, but as the day warms little rivulets 
 begin to flow on the surface of the ice; where there is much crevassing 
 the water finds its way quickly to the base of the glacier, and there it 
 may be heard rushing down the slope. From the front of the ice 
 there flow rushing streams white with silt from the rock ground fine 
 beneath the glacier, the “gletschermilch” of the Germans. The main 
 or eastern part of Blackfeet Glacier is somewhat less crevassed and 
 more water flows in rivulets upon the ice. These unite to form 
 streams a foot or two in width, but of high velocity, since the surface 
 of the glacier has toward the front a 15° slope. The sharply sinuous 
 channels cut in the ice reach, in places, depths of 20 to 35 feet. At 
 one point a stream was seen plunging down a vertical well, or moulin, 
 to join the subglacial flow. The depth of such a hole might be 
 measured to ascertain the thickness of the ice. 
 
 Worlc of the glacier. —The work of such a glacier as that being 
 described is manifested in the production of the cirque or amphitheater 
 which it occupies, in the abrasion of the rock floor over which it 
 moves, and in the deposits resulting from the drift which it produces 
 and transports. 
 
 The greater part of the rock composing the mountains of the park is 
 stratified in layers, mostly thin, but ranging in thickness from a 
 fraction of an inch to 30 feet or more. The strata are generally 
 broken at frequent intervals by cracks or joints, and water percolating 
 into these crevices expands on freezing and forces the pieces apart. 
 Alternate freezing and thawing breaks up and loosens the fragments 
 ready to be removed. Many fall or are carried down from the cliffs 
 and upper slopes by avalanches of snow. Others beneath and 
 behind the glaciers become frozen in the moving ice and are plucked 
 from their places and slowly carried away. The ice always advances 
 and never retreats, so that as long as the glacier exists, unless it 
 becomes absolutely stagnant, material is continually being removed. 
 A glacier may thus be said to gnaw continually at the slope and eat 
 its way back into the mountain. 
 
 Some geologists maintain that the breaking up of the rock and the 
 plucking away of the loosened fragments is particularly facihtated by 
 changes in temperature in the air and the water admitted by the 
 yawning bergschrund which is so often seen in the neve at the back 
 of the glacier. Continued sapping steepens the walls until the great 
 amphitheaters or cirques are produced. The Blackfeet Glacier does 
 not occupy such a deep and symmetrical cirque as is seen at many 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 9 
 
 other places in the park. It is probable, however, that this is still 
 being extended back into the mountain slope. 
 
 Only a relatively small amount of rock debris falls from the upper 
 mountain slopes onto the Blackfeet Glacier, and there is little or no 
 drift seen embedded in the ice exposed in the sides of the crevasses, 
 neither is any being carried by the surficial streams. Looking into 
 caverns under the ice, one sees here and there pebbles and bowlders 
 at or in the bottom of the ice, and the undersurface is coated with a 
 thin layer of mud, the product of the grinding of the fragments and 
 of the rock bed beneath the glacier. One sees also the smoothed, 
 polished, and striated rock surface extending back beneath the base 
 of the moving ice. A glacial quarry was observed in the upper part 
 of the bared space between the northwest margin of the Blackfeet 
 Glacier and the moraine. Here the ice has evidently plucked loosened 
 blocks from the exposed edges of the strata as quarrymen remove 
 layer from layer in the process called stoping. Many blocks derived 
 in this way are found incorporated in the morainal embankments. 
 Some of the blocks are but little worn, as though transported on the 
 surface of the ice, but most of them are subangular with polished and 
 striated facets, showing the effects of abrasion beneath the glacier. 
 Much of the morainal material is fine rock flour. The whole con¬ 
 stitutes a heterogeneous deposit of unassorted glacial till. Sharp 
 morainal embankments border nearly the whole frontal margin of 
 the Blackfeet Glacier (fig. 13, p. 24). 
 
 Former extent of the glacier .—The marginal lobes of the main eastern 
 part of this glacier, like the western lobe, are somewhat shrunken 
 from their moraines, an indication that some tune ago the ice had a 
 greater extension. 
 
 On the slope between Gunsight Camp and the glacier the surface 
 of the limestone is in most places somewhat roughened as a result 
 of etching by solution by the water flowing over it. In places, 
 however, the surface is smooth, polished, and scratched the same as 
 the rock surfaces within the moraines. This indicates that at some 
 time the glacier extended beyond the limits now marked by the mo¬ 
 raines. Similar glaciated surfaces are found far down St. Mary 
 Valley, and the valley bottom and lower side slopes carry glacial 
 drift quite to the international boundary, a distance of 38 miles from 
 the divide at Blackfoot Mountain. Such drift extends up the slope 
 east of Lower St. Mary Lake nearly to 5,800 feet above tide; i. e., 
 1,300 feet above the lake. Drift was also found on the slope of 
 Singlcshot Mountain west of Upper St. Mary up to an elevation about 
 1,200 feet above the lake. Moreover, that part of St. Mary Valley 
 within the mountains has not the sharply cut V-shaped transverse 
 profile of a stream-cut mountain gorge, but has the broadly rounded 
 U-shaped profile typical of a glaciated valley. Tributary to St. 
 
 36592°—14-2 
 
10 
 
 GLACIERS OF GLACIER XATIOXAL PARK. 
 
 Mary \ alley above the lower lake are more than 25 cirques, which 
 formerly contained glaciers. From such evidence it is apparent that 
 the whole St. Mary Valley as far down as the international boundary 
 was once occupied by a great glacier, of which Blackfeet Glacier and 
 17 other smaller glaciers remain as the only representatives in this 
 part of the park. (See map facing page 32.) The contours of the 
 valley indicate that the great St. Mary Glacier must have had a 
 thickness of 2,000 to 2,500 feet where is now Upper St. Mary Lake. 
 
 Glacial modification of St. Mary Valley .—Figure 1, A and B, which 
 is based on the contours of Swiftcurrent Valley, illustrates the differ¬ 
 ence between a stream-cut mountain valley and the same valley after 
 it has been subjected to vigorous glaciation. In the paper by Mr. 
 M. R. Campbell on the origin of the scenic features of the park, it is 
 pointed out that the formation of the great mountain valleys was 
 
 A . 
 
 B . 
 
 Fig. 1.— A , Sketch of stream-cut valley; B , sketch of same valley after 
 
 MODIFICATION BY GLACIATION. 
 
 due primarily to the work of streams which cut deeply into the moun¬ 
 tain mass. When climatic conditions became such as to result in 
 the vast accumulation of snow great glaciers developed in each of 
 the mountain valleys. As the glaciers gradually extended all of the 
 loose rock debris which had accumulated on the lower part of the 
 slopes and at their feet became frozen into the base of the ice. Par¬ 
 tially loosened blocks were also plucked away bodily and moved 
 forward down the valleys. A mass of ice 2,000 feet in thickness 
 exerts a pressure of 56 tons per square foot on the bed upon which it 
 rests. The rock-shod ice thus became in effect an enormous rasp, 
 which scored and polished and wore away all the minor irregularities 
 of the slopes and bottoms of the valleys. Such enormous masses 
 of moving ice do not adjust themselves to the sinuosities and irregu¬ 
 larities of the valleys as readily as does water in its liquid state. In 
 consequence of this and of the enormous weight of the moving mass, 
 every opposing ledge and mountain spur were subjected to vigorous 
 abrasion; the valley bottom was broadened and the side slopes were 
 steepened until the whole became a broad open trough. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 11 
 
 The attitude of the rock strata and the resistance which they 
 offered to removal as a consequence of differences in hardness or in 
 massiveness of bedding determined in some degree the depths to 
 which the valley was deepened in various parts. Thus a particularly 
 resistant stratum, such as the massive ledge of limestone which crosses 
 St. Mary Valley at the narrows in Upper St. Mary Lake, was not 
 worn away to the same extent as were the softer rocks farther down 
 the valley or the thinner-bedded rocks above. Broader basins were 
 thus developed above and below this ledge, and when the ice melted 
 away these basins were filled with water, forming a lake. The failure 
 to cut as broad a channel through the limestone ledge caused the 
 constriction or narrows in Upper St. Mary Lake. In some of the 
 other valleys, such as Swiftcurrent Valley, a lake was formed above 
 the ledge, but no channel was cut through, so that the escaping waters 
 plunge in a foaming cascade over the obstruction to the valley below. 
 Moraines and other deposits of drift were left on the melting of the 
 great valley glaciers, and in some places lakes, such as Bowman Lake 
 and Quartz Lake, are due, in part at least, to the blocking of the 
 valleys by such accumulations of drift. 
 
 HARRISON GLACIER. 
 
 One of the interesting trips from Gunsight camp is southwestward 
 up the smooth, snow-covered surface of the upper western part of the 
 Blackfeet Glacier to the crest of the Continental Divide in the notch 
 southeast of Jackson Mountain. Looking westward from this point 
 one gets a magnificent view of the cascading lobes of Harrison Glacier 
 (fig. 2). The main glacier, which lies high in the upper northern part 
 of the great cirque at the head of Harrison Creek, is seven-tenths of 
 a mile wide from east to west and nearly a mile long from north to 
 south. From this a series of ice lobes spill over and cascade down 
 the steep slope to benches in the great cirque wall. Of these the one 
 nearest the observer and the one farthest away appear to extend to 
 well-marked moraines, the one near by does not reach the highest 
 and outermost of the ridges, but ridged drift is spread over the space 
 between the ridge and the ice front. The front of the fourth is some 
 distance back from the end moraine, from which two finely developed 
 laterals extend up the slope. The fifth lobe breaks off at the top of 
 a cliff over which its morainal material is pushed. 
 
 SPERRY GLACIER. 
 
 General relations .—High up in the upper cirque at the head of 
 Avalanche Basin lies Sperry Glacier 1 (fig. 12,p.24). This is next in size 
 to Blackfeet Glacier, having a maximum width at the front—i. e., from 
 
 1 In January, 1896, there was published in Appalachia (Vol. VIII, pp. 57-69) an article by Lyman B. 
 Sperry on Avalanche Basin, Montana Rockies, in which he described explorations of this basin made in 
 May and July, 1895, by a party of which he was a member. An effort was made at this time to reach the 
 upper cirque and find the source of the waters which were seen to be milky with glacial silt. It was not, 
 however, until 1896 that Dr. Sperry succeeded in reaching the glacier which now bears his name. (See 
 Glaciers in the Montana Rockies, by L. W. Chaney, jr., Science, new ser., Vol. IV, pp. 761-762,1896.) 
 
12 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 Fig. 2.—Harrison Glacier, showing the cascading frontal lobes. 
 
 Photograph by W. C. Alden. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 13 
 
 northeast to southwest—of 1^ miles—and a length—i. e., from north¬ 
 west to southeast—of about 1 mile. Its area is estimated as about 1 
 square mile. The great cirque at the head of Snyder Creek between 
 Edwards Mountain on the south and Mount Brown on the north was 
 excavated so far back into the mountain mass that the upper part of 
 the divide between Snyder Valley and Avalanche Basin was cut 
 away, leaving a broad notch between Edwards Mountain and the 
 small pyramidal peak known as Little Matterhorn. Through this 
 col some of the water from the eastern part of Sperry Glacier goes 
 to Snyder Creek. A similar notch was also developed between 
 Edwards Mountain and Gunsiglit Mountain. It is through this 
 latter notch that the trail climbs from the creek at the crossing below 
 
 Fig. 3.—Moat at east side op Sperry Glacier, showing stratification in 
 
 THE ICE WALL ON THE RIGHT. 
 
 Photograph by W. C. Alden. 
 
 Sperry Camp, about 6,200 feet above tide, to the southwest side of 
 the glacier at 7,700 ± feet above tide. 
 
 The surface of the ice is for the most part smooth and not crevassed 
 and may be crossed in any direction. With care one may also de¬ 
 scend the slope to the frontal margin. At the southwest side, the 
 front is about 450 feet lower than the top of the iron ladder. It is 
 at and near the front of the ice that the most interesting phenomena 
 arc to be observed. 
 
 Structure .—In the front slope soiled zones mark the outcropping of 
 the dirty surfaces of successive ice strata, each the residuum of one 
 or more year’s snowfall. Other than this the surface of the glacier is 
 almost entirely clean of debris excepting on the lower part of the 
 frontal slopes immediately adjacent to the ice margin where there is 
 a scattering of pebbles and bowlders with a little clay. The stratifi- 
 
14 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 cation may also be seen in the sides of the few open crevasses. The 
 best view, however, of the bedded structure of the glacier is to be 
 had where the east side of the glacier rounds a salient of the cirque 
 wall at a point about two-fifths of a mile south-southeast of the front 
 
 Fig. 4.—Sperry Glacier, bergschrund on slope of 
 Edwards Mountain. 
 
 Photograph by W. C. Alden. 
 
 of the most easterly marginal lobe of the glacier. On the northwest 
 side of the point of the salient instead of the ice crowding against the 
 rock slope there is a great chasm, or moat (fig. 3), one side of which 
 is formed by the rock wall. The other is a smooth, curving wall 
 of stratified ice, 150 feet or more in height. This moat is probably 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 15 
 
 due, in part, to the fact that the ice passing the rock salient does not at 
 once spread laterally after passing the point. The lower part of the 
 cliff thus exposed is warmed by the afternoon sun and radiates a cer¬ 
 tain amount of heat which, melting the ice, tends to prevent its closing 
 up the moat until it has passed on some distance around the point 
 or may even actually enlarge it. The water resulting from the melting 
 escapes laterally beneath the glacier so that the moat, at least when 
 visited by the writer in August, 1913, contained no stream or ponds. 
 
 Ice caves and glacial movement .—In the upper part of the neve on 
 the slope of Edwards Mountain a bergschrund (fig. 4) yawns as the 
 result of the ice moving away from the mountain slope. At several 
 points along the front of the glacier there are small caverns. Instead 
 of breaking down immediately after passing the highest part of a 
 ledge, the ice projects forward as an arch fluted in correspondence 
 with the inequalities of the ledge surface. One such ice cave 
 was seen into which a person could walk a distance of 50 or 60 
 feet from the entrance, and probably one could proceed an equal dis¬ 
 tance farther if disposed to crawl on his hands and knees on the wet 
 rock. In these caverns the fact that the ice is really in motion may 
 readily be demonstrated. Markers were placed in the ice walls and 
 upon the ledges, and the distance between the marker in the ice and 
 that on the ledge was carefully measured with the following results: 
 
 Movement of ice in ice cave No. 1, at point S. 37° E. of Little Matterhorn. —12.15 p. m., 
 August 15, to 11.15 a. m., August 16; advance of one-fourth inch in 23 hours. 11.30 
 a. m., August 16, to 10.25 a. m., August 17; advance of one-half inch in 24 hours. 10.30 
 a. m., August 17, to 11.15 a. m., August 17, advance of one-eighth inch in 45 minutes; 
 11.15 a. m to 4 p. m., advance of one-eighth inch in 4f hours. 
 
 Movement of ice in ice cave No. 2 at point S. 43° E. of Little Matterhorn. —Noon, Au¬ 
 gust 16, to noon, August 17, advance of one-half inch in 24 hours. 
 
 Movement of ice in ice cave No. 3, west side of middle ice lobe, at point S. 87° E. of Little 
 Matterhorn. —1.15 p. m., August 16, to 1.15 p. in., August 17, advance of three-fourths 
 inch in 24 hours. 
 
 Movement of ice in ice cave No. 4 at west side of eastern ice lobe at point S. 45° E. of 
 Heavens Peak. —2.30 p. m., August 16, to 2.30 p. m., August 17, an advance of about 
 one-half to three-fourths inch in 24 hours; markers loosened by melting. 
 
 The measurements have not been continued over a sufficiently long 
 period to warrant basing upon them an estimate of the average daily 
 or total yearly advance. The measurements made in cave No. 1 
 show the variations in the rate of motion due to difference in tempera¬ 
 ture. On the first day, August 15, when the weather was cold and 
 blustering, with some snow falling, an advance of but one-fourth inch 
 was noted. During the following 24 hours the weather became bright 
 and warm, there was much melting of the ice, and the advance noted 
 then was one-half inch. 
 
 ' Moraines .—The front of the glacier is bordered by well-marked 
 terminal moraines. These are sharp, narrow, and uneven-crested 
 embankments 20 to 50 feet in height, composed of intermingled clay, 
 
16 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 or rock flour, pebbles, and bowlders. Generally there is an interval 
 of a few rods between the ice and the mam ridges, showing that the 
 glacial margin has retreated somewhat since the formation of the mo¬ 
 raine. The foot of the glacier, for the most part, rests on nearly bare 
 rock, but in one place it appears to lie on top of a morainal accumula¬ 
 tion nearly 50 feet hi height (fig. 5). Here one sees the moraine hi 
 process of construction. It is possible that the drift here merely 
 covers the margin of the glacier so that the core of the ridge is of ice* 
 The southwest half of the glacier is underlain by banded red and 
 white quartzite and argillite, while the floor of the northeast half of 
 the cirque is composed of the grayish to buff limestone. As a result 
 the southwest half of the terminal moraine is composed principally of 
 
 Fig. 5.—Moraine at front of Sperry Glacier. 
 
 Photograph by W. C. Alden. 
 
 maroon-red argillite and quartzite, and the water in the brooks and 
 morainah ponds is reddish from the silt held in suspension. The 
 northeast half of the moraine, on the contrary, is composed mostly 
 of grayish limestone, and the water of the ponds and streams issuing 
 here is white, the typical “gletschermilch.” 
 
 At two places marginal lobes of the ice project forward in trougli- 
 like depressions in the rock floor of the cirque. Where these ice- 
 tongues occur the moraine bends sharply and extends parallel to the 
 sides of the lobes as lateral moraines. These laterals are connected 
 in a large loop about the end of each ice lobe. 
 
 A short distance outside the inner morainal belt is one of earlier 
 formation disposed hi loops indicating that the ice margin was for¬ 
 merly somewhat more lobate than at present. This outer moraine 
 is subdued in contour, the irregularities of crest and slope having been 
 
I 
 
11420 ' 
 
 114 10 ' 
 
 113 ' 50 ' 
 
 113 40 ' 
 
 113 30 ' 
 
 113 20 ' 
 
 
GLACIERS OF GLACIER NATIONAL PARK. 17 
 
 partially washed away, and is covered in part by a scanty growth of 
 dwarfed trees. 
 
 y Rock scoring and plucking .—In the ice caverns the observer gets an 
 excellent idea of the abrasive work done by the glacier. The surface 
 
 Fig. 6.—Glaciated groove near front of Sperry Glacier. 
 
 Photograph by W. C. Alden. 
 
 of the bed rock is beautifully smoothed, polished, and striated. This 
 surface is seen to extend back under the moving ice whose under¬ 
 surface is plastered with a thin coating of wet mud or rock flour, and 
 set with fragments of rock. This is the abrasive material with which 
 the work is done. There seems to be no considerable amount of 
 36592°—14-3 
 
18 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 gravel or rock fragments in the base of the ice, as removal of the sub- 
 surfieial coating shows clear, clean ice above. Here may be seen 
 how the ice, melting under pressure against inequalities of the rock 
 surface, is fluted with grooves corresponding to those irregularities, 
 while at the same time all the small projections are being worn away. 
 
 Not only does the surface of the rock floor of the cirque within the 
 moraines show the effects of glaciation, but between the outer moraine 
 and the lip of the cirque, below which the great cliff drops to form the 
 head of Avalanche Basin, the rock is smoothed, polished, striated, 
 and grooved in a remarkable manner. In places the ice has been 
 forced along more or less tortuous grooves, which were probably first 
 worn by water running beneath the ice (fig. 6). 
 
 The method of glacial quarrying known as plucking is also well 
 illustrated. At one place east of Little Matterhorn the striated floor 
 is cut by a vertical northeast-southwest joint face. Beyond this a 
 lower level was in process of being developed by stoping when the 
 ice was melted away. Some great blocks of rock 10 by 15 by 20 feet 
 in size have been loosened along the joints and moved distances 
 ranging from a few inches to several feet. Others have been moved 
 50 to 100 yards or more and left stranded between the quarry face and 
 the lip of the upper cirque. Still others, doubtless, were forced on 
 over the cliff to be dashed in fragments on the ledges below. At one 
 point the opposed faces of a joint, now 3 to 5 feet apart, are striated 
 in a direction transverse to that of the striae of the main ice movement 
 on the floor above as though the basal ice had squeezed laterally into 
 the crack and gradually forced the block on the northeast away from 
 its original position. One joint but a few feet back from the crest 
 of the cliff at the head of Avalanche Basin has been broadened 
 several feet to a considerable depth. Had the disrupting action 
 continued but a little farther a great mass of the upper part of the 
 cliff would have been tipped over into the great cirque below. It is 
 largely by such processes of glacial plucking or stoping that the 
 great cirques have been excavated. It seems probable that only a 
 subordinate amount of material was removed by abrasion beneath 
 the great rasp formed by the rock-shod ice. 
 
 Former extent of the glacier .—The relations are such that there can 
 be no doubt that in comparatively recent time, geologically speaking, 
 though thousands of years ago, Sperry Glacier not only occupied the 
 whole of the upper cirque but filled Avalanche Basin and was con¬ 
 fluent with a great glacier in the canyon of McDonald Creek (see 
 map facing p. 32). 
 
 At its southwestern end the terminal moraine is near the crest of 
 the cliff at the head of Snyder Creek. Some of the water from the 
 western part of the glacier flows over this cliff. The trend of the 
 striae outside the moraine also indicates that some of the ice formerly 
 passed through the gap between Edwards Mountain and Little Matter- 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 19 
 
 horn and joined a glacier in Snyder Creek Akalley. It is also probable 
 that some of the ice went through the gaps between Edwards Moun¬ 
 tain and Gunsight Mountain to a glacier in Sprague Creek Valley. 
 
 All over the rock shelf on which stands Sperry Camp and on the 
 ledges along the trail to Sperry Glacier there is a fine exhibition of 
 the polishing and striating action of the glacier which formerly 
 occupied the valley. Striae on some vertical faces beside the trail 
 slope steeply, in places nearly or quite vertically, showing how the 
 ice descended from ledge to ledge. 
 
 SWIFTCURRENT GLACIERS. 
 
 Grinnell Glacier .—The largest of the glaciers at the heads of tribu¬ 
 taries of Swiftcurrent Valley is the Grinnell Glacier, so named in 
 honor of Mr. George B. Grinnell, one of the first to explore these moun¬ 
 tains. This occupies the upper cirque on the north side of Gould 
 Mountain. From Sherburne Lakes, 10 miles distant, the white and 
 glistening glacier may be seen nestling at the foot of the Garden 
 Wall in the cirque between Gould and Grinnell Mountains. While 
 not so readily accessible as some of the other glaciers this one can be 
 reached from Many-Glacier Camp by going up Cataract Creek trail 
 along the west shore of McDermott Lake and then climbing up and 
 along the south slope of Grinnell Mountain (figs. 7 and 8), or one may 
 get a fine view of it from above by a climb from Granite Park to a 
 notch in the Garden Wall. 
 
 This glacier has a width from northwest to southeast of about 1§ 
 miles and a length from southwest to northeast of about 1 mile. 
 Its area is a little over 1 square mile. It consists of a neve-covered 
 upper part, lying on an upper bench in the western part of the cirque, 
 and the main glacier, whose lowest point is not far from the crest 
 of the cliff which rises abruptly nearly 1,000 feet from the valley 
 floor above Grinnell Lake. Through most of its lateral extent the 
 upper mass of ice ends at the crest of the bare rock ledge below the 
 upper bench. South of this, however, the ice cascades over the ledge 
 with a much crevassed surface to the main glacier below. From the 
 encircling cliffs the ice flow converges toward the lowest point in the 
 lip of the cirque. A large part of the surface is crevassed, showing 
 that the ice is moving down over an uneven bed, and nearly the whole 
 surface is banded with the soiled zones which mark the outcropping 
 of the ice strata. A morainal embankment, consisting of narrow 
 sharp-crested ridges of drift 30 to 100 feet in height, closely borders 
 the ice margin on the east and north. (Figs. 7, 8, and 9.) This is in 
 part lateral and in part a terminal moraine. 
 
 In a little niche at the side of a deep notch in the crest of the Gar¬ 
 den Wall back of Gould Mountain, a thousand feet or more above the 
 main glacier, is a fine example of a cliff glacier (fig. 8). This glacier 
 is short and relatively thick. From the crest of the rock cliff its 
 
20 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 nearly vertical face of glistening stratified ice rises 100 feet or more 
 to the smoothly rounded, snow-covered crest (fig. 10). 
 
 On the north side of Grinnell Mountain lies another small glacier on 
 a rock shelf at the top of a 1,500-foot cliff. This is in view of tourists 
 
 Fig. 7.—Gould Mountain and Grinnell Glacier. 
 
 Morainal ridge at left and in foreground. 
 
 Photograph by T. W. Stanton. 
 
 traversing the trail to Swiftcurrent Pass. The ice, which is much 
 crevassed, extends to the crest of the cliff in places and dumps some 
 of its morainal drift into the abyss below. 
 
 In the next cirque north of Swiftcurrent Pass there is a notable 
 development of steps or benches due to the stoping action in cirque 
 
GLACIERS OF GLACIER NATIONAL PARK 
 
 21 
 
 formation being carried on at several different levels. These arc good 
 examples of steps in a so-called “ glacial staircase.” There are two 
 
 Fig. 8. —Grinnell Glacier, upper part, crest of moraine in foreground. 
 
 Gem Glacier above at left. 
 
 Photograph by T. W. Stanton. 
 
 Fig. 9.—Moraine of Grinnell Glacier. 
 
 Piegan Mountain in background. 
 
 Photograph by T. W. Stanton. 
 
 of these benches in the upper part of the cirque, and on these lie four 
 distinct little glaciers (fig. 11). 
 
22 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 Iceberg Lake and Glacier .—The charm of the view at the head of the 
 North Fork of Swiftcurrent Creek lies in the combination of the 3,000- 
 foot, vertical, encircling wall of the amphitheater, the small glacier 
 lying at its base, the beautiful little lake of deepest blue, and the daz- 
 
 Fig. 10.—Front of Gem Glacier; on the Garden Wall 
 
 ABOVE GrINNELL GLACIER. 
 
 Photograph by T. W. Stanton. 
 
 zling whiteness of the small icebergs usually floating in the lake (fig. 
 14). With these masses of glacier ice there are usually cakes of lake ice 
 floating even in August. Along the east shore of the lake is an “ice 
 rampart” of bowlders probably pushed up by the forward crowding 
 of the ice when the lake is frozen over in the winter. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 23 
 
 Crossing the shallow outlet stream one finds a way along the talus 
 slope and over the ledge around the north shore of the lake. There 
 is a considerable accumulation of angular and unworn rock fragments 
 piled on the ice at the north side. This has evidently fallen from the 
 cliffs and has been handled by the glacier only enough to pile up sharp 
 morainal ridges 30 to 40 feet in height. Crossing these one reaches 
 
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 the main part of the glacier (fig. 15), upon which there is also a sprink¬ 
 ling of rock fragments. Toward the front the ice is broken by 
 crevasses (fig. 16), and much of this drift must fall into these yawning 
 cracks, and thus reach the base of the ice, there to be ground and 
 polished beneath the moving glacier and pushed forward into the lake. 
 In the ice walls of these crevasses the banded, stratified structure of 
 the ice is well displayed. In that part south of the morainal ridge 
 where seen by the writer, the banding is longitudinal, i. e., parallel to 
 
Fig. 12. —Sperry Glacier from Little Ma' 
 
 Fhotograp 
 
 Fig. 13. —Blackfeet Glacier, eastern part, Black] 
 
 Photograph 
 
RHORN, GUNSIGHT MOUNTAIN IN BACKGROUND. 
 
 W. C. Alden. 
 
 t Mountain and Jackson Mountain in background. 
 
 W. C. Alden. 
 
 
26 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 the direction of the ice flow, and it is seen in the sides of the crevasses 
 to dip southward at an angle of from 30° to 45°. In the front 
 of the glacier this dip is seen to decrease southward and become nearly 
 horizontal or slightly undulating and to extend thus across the glacier. 
 
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 Toward the south side the banding appears to curve again downward 
 at a high angle which decreases again townrd the south wall. 
 
 The front of the glacier is now nearly a mile back from the crest of 
 the cliff over wdrich the trail climbs to the upper cirque. Striations 
 on the rock ledges east of the lake show that at some former time the 
 ice extended across and beyond the rock basin in wdiich the lake now 
 lies. Loosened and partially removed blocks of rock at and near the 
 cliff between the lower valley and the upper cirque suggest the method 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 27 
 
 Fig. 15.—Front op glacier at Iceberg Lake. 
 Photograph by W. C. Alden. 
 
 Fig, 16, —Glacier at Iceberg Lake showing crevasses and rock debris on 
 
 the ICE. 
 
 Photograph by W.C. Alden. 
 
28 
 
 GLACIERS OF GLACIER NATIONAL PARK 
 
 DUE TO GLACIATION. 
 J’holograph by M. R. Campbell. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 29 
 
 by which the more extended moving ice was stoping back the cliff 
 face when the melting of the ice ended the operation. 
 
 Canyon Creek Glacier .—Above the beautiful lake at the head of Can¬ 
 yon Creek one may cross the alluvial fan and climb the steep slope of the 
 moraine which is being built up by a small glacier. The glacier, which 
 is almost covered with rock fragments fallen from the great encircling 
 cirque wall, is considerably crevassed as though crowding forward over 
 the lip of the cirque. A still higher bench in the back of the cirque 
 holds a small crevassed glacier and high up upon the west side in a 
 niche above a projecting ledge is a third. 
 
 Former extent of the ice .—The broadly rounded, U-shaped profiles of 
 the valley (fig. 17), the oversteepened side slopes with small amount 
 of talus, the glaciated rock ledges, and deposits of glacial drift, to¬ 
 gether with other general relations, indicate that during the last, or 
 Wisconsin, stage of the glacial period, Swiftcurrent Valley and all its 
 tributaries were occupied by a great glacier which was in turn tribu¬ 
 tary to a former glacier which may be called the St. Mary glacier (see 
 map facing page 32). The small existing glaciers described above are 
 the diminutive remnants of this great stream of ice. The height to 
 which Swiftcurrent Valley was filled by this glacier is not definitely 
 known, but it probably reached 2,000 or 2,500 feet. High upon the 
 mountain slope to the north, about 1,600 feet above the outlet of 
 McDermott Lake, the writer observed rock ledges which had been 
 polished and striated by ice moving eastward down the valley. Simi¬ 
 lar striae were also seen on the northwest slope of Allen Mountain at 
 about the same height above the lake. About 5 miles farther east 
 where this glacier joined the trunk of the former St. Mary glacier the 
 ice must have been at least 1,000 feet thick, judging from the eleva¬ 
 tions of the moraine which incloses Duck Lake, 3 to 6 miles east of the 
 village of Babb. 
 
 BELLY RIVER GLACIERS. 
 
 Glaciers at Ahern Pass .—From Granite Park a trail leads northward 
 to Ahern Pass. By this route one may cross the divide and descend 
 Belly River Valley. From the pass down to the upper lake the trail 
 is passable for pedestrians using caution but is not in condition for 
 saddle or pack animals. August 22, 1890, Lieut. George P. Ahern 1 
 led a party, consisting of a detachment of soldiers from the Twenty- 
 fifth Infantry, Mr. G. E. Culver and two prospectors, with packers, 
 Indian guides, and a pack train, up Belly River Valley and across the 
 pass which bears his name. 
 
 One interesting feature of this trail is that after passing the divide 
 it leads down across the upper part of the sloping surface of a small 
 glacier and then passes out along the steep valley side, which is cov- 
 
 1 Notes on a little known region in northwestern Montana, by G. E. Culver, Trans. Wis. Acad. Sci., 
 vol. 8, pp. 185-205, 1888-91. 
 
30 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 ered with loose sliding rock excepting where there are precipitous 
 rock ledges. The surface of the small glacier descends steeply about 
 500 feet to the crest of a cliff which drops down thence 1,000 feet to 
 the head of the valley below (fig. IS). The angle of slope of the ice 
 for several hundred feet above its foot is about 45°, and this steep 
 slope is in part scored by open crevasses. It is not a suitable place 
 for coasting. This glacier occupies a niche in the upper south wall of 
 the great cirque just below the pass. The main head wall of the 
 amphitheater is one of the most imposing in the park. The peak at 
 its crest north of the pass stands nearly 3,600 feet above the upper 
 lake. Of this the upper 2,500 feet stands almost vertical. Below 
 this some small glaciers, with their neve banked against the base of 
 the cliff, spread out slightly on the rock bench above the lake. These 
 
 Fig. 18.—Glacier at Ahern Pass. 
 
 Photograph by T. W. Stanton. 
 
 are bordered by comparatively large moraines. One of these as seen 
 from above surrounds the narrow end of the glaciers as a sharp V, 
 like the nose of a snow plow (fig. 19.) The ice appears to be thinned 
 as the ridge stands up abruptly from its debris-covered surface. A 
 short distance outside this is an earlier moraine covered with vegeta¬ 
 tion and encircling a pond of water. 
 
 At the top of the vertical northwest wall of the cirque is another 
 glacier about 2,600 feet above the lake. This lies 500 feet or more 
 above the level of Ahern Pass so that only its front edge can be seen 
 from that point. To one looking down upon it from the mountain 
 top above it appears as a considerable mass of ice with a width from 
 north to south of seven-tenths of a mile and a length from northwest 
 to southeast of one-half mile. The frontal margin is pushed forward 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 31 
 
 quite to the crest of the cliff and in places appears to overhang so 
 that the drift as it is thrust forward, and doubtless some of the ice 
 also, falls over the precipice and the streams hang on the dark rock 
 wall like silvery threads. 
 
 Chaney Glacier .—From a camp on Flattop comparatively easy 
 access to the glaciers at the head of Middle Fork of Belly River is 
 
 Fig. 19.—Glaciers and moraines near Ahern Pass. 
 
 Photograph by W. C. Alden. 
 
 gained by climbing to the potch in the crest of the mountain wall at 
 the head of Mineral Creek. All five of these glaciers occupy scallops 
 in the great upper cirque, above the tops of the cliffs against which 
 head the main floors of the two branches of the Middle Fork. 
 
 From the notch, which is at about 7,950 feet above sea level, one 
 sees Chaney Glacier spread out at his feet. This glacier was named 
 
32 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 in honor of Prof. L. W. Chaney, jr., 1 of Carleton College, of North- 
 field, Minn., who visited it in 1895. 
 
 Chaney Glacier (fig. 20) has a width from northwest to southeast 
 of about 1 mile. From its upper edge, about 15 or 20 feet below the 
 
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 notch in the divide, the smooth surface of the ice slopes northward. 
 At the top the slope is gentle, but toward the front it is steeper, 
 descending about 1,200 feet in a distance of one-half mile. At the 
 north side of the eastern part of the glacier the ice extends as a nar¬ 
 rowing tongue down into a notch in the lip of the upper cirque. 
 
 1 Appalachia, Vol. VIII, 1896-1898. 
 

ALBERTA 
 
 MONTANA 
 
 C lit b (vh 
 
 ‘owinnnmi 
 
 ' V . . \ if ■ <V I 
 
 Jpl* y ' 1 H 11: 
 
 .jfof EASTERN PORTION OF 
 
 V* GLACIER NATIONAL PARK 
 
 j AND ITS ENVIRONS 
 
 DURING THE GREAT ICE AGE 
 
 iffflaciprlPstrk'' 
 
 PSiummimt 
 
 Extent of Rocky Mountain glaciers and Keewatin ice sheet 
 during the last or Wisconsin stage of glaciation. 
 
 Areas in which deposits of the earlier or pre-Wisconsin 
 mountain glaciers and associated gravel are preserved on 
 remnants of the older high-level plains. 
 
 Mountain crests and rock surfaces that were probably not 
 covered by the Rocky Mountain glaciers. 
 
 .lijHeart Butte 
 
 Areas in which glaciers exist at present 
 
 Wm. C. Alden and Eugene Stebinger, U. S. Geological Survey. 1914. 
 
 0 
 
 i 
 
 i£. 
 
 '± 
 
 20 MILES 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 33 
 
 The smooth surface of the glacier is banded from side to side by 
 curving zones of darker color. These are the soiled zones due to the 
 concentration of dust and small rock fragments which accumulated 
 on the surface of each successive winter’s snowfall. They thus dif¬ 
 ferentiate the outcropping edges of the ice strata of which the glacier 
 is composed. 
 
 When seen by the writer in 1911 and 1913 the ice was but very little 
 crevassed, though a few cracks were open near the front of the lobe 
 and in the upper part the latter were partially filled with snow. 
 Interesting features seen in a few places were ice dikes 6 or 8 inches 
 thick. These are formed by water freezing in the cracks. When 
 subsequently there has been a little melting at the surface the parallel 
 crystals may be raked out loosely with a pick. Similar but radial 
 structures are seen in several places where circular cavities several 
 inches in diameter have been filled by ice crystals growing converg- 
 ently from the encircling ice wall toward the center of the cavity. 
 Such features were called “gletschersternen,” or “glacier stars,” by 
 Prof. Agassiz. 
 
 About 250 yards below the notch in the divide by which the 
 glacier is reached from the south there is a zone extending laterally 
 part way across the glacier in which there are many ice wells or 
 moulins. These are vertical holes hi the ice varying in diameter 
 from 1 to 6 feet. Many of them, especially those into which stream¬ 
 lets of water plunge after flowing on the surface of the ice, appear 
 to extend to the bottom of the glacier. Others from which the 
 streams have been diverted are partially filled with snow. Sound¬ 
 ings made by the writer in several of the wells with a cord and stone 
 show depths ranging from 25 to 74 feet, the deepest being near the 
 center of the main ice stream. These are regarded as measures of 
 the thickness of the ice at these several points, since it seems prob¬ 
 able that the water descends to the rock floor of the cirque before 
 flowing away beneath the ice. These wells are arranged in lines 
 transverse to the direction of ice flow and appear to have been 
 developed along cracks which now at least are tightly closed though 
 visible. At points where cracks were opened across the course of 
 rivulets, or where rivulets developed across cracks already opened, 
 percolation of water down the cracks may have initiated the thaw¬ 
 ing of holes which were gradually enlarged to their present dimen¬ 
 sions. These wells were not noted farther down the slope in the 
 central part of the glacier. It may be that along this zone is a posi¬ 
 tion where successive cracks develop, though there are no open 
 crevasses at this place. After one set of cracks and moulins have 
 developed and moved a short distance down the slope the opening 
 of new cracks in the former position may lead to the development 
 
34 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 of a new set of moulins, giving new apertures by which the w T ater is 
 diverted to the base of the ice above the former line of wells. Sub¬ 
 sequently these latter may become filled with snow and contracted 
 by pressure until no openings remain. In a direction somewhat 
 west of north from the notch in the divide, at the 'west side of the 
 main current to the frontal lobe of the glacier is a mound of buff 
 argillite fragments. About the head or south side of this are clus¬ 
 tered many of these ice wells, so that this part of the glacier must be 
 crossed with care. 
 
 Near the w 7 est side of this mound was seen a larger hole about 15 
 feet long shaped like a bathtub. This w’as filled with water to 
 within a few feet of the surface and in the w’ater floated a tiny ice¬ 
 berg. This is a good example of the cavities designated “ baignoires,” 
 or “bathtubs,” by Prof. Agassiz. 1 Soundings showed this “bath¬ 
 tub” to be 12 feet deep. It is not evident what would cause the 
 development of so deep a cavity in the ice, as it appears not to be 
 due to running water, at least the bottom and sides are now so 
 tightly closed that the water is retained. Possibly it was once a 
 moulin like those farther up the slope, which after being abandoned 
 by the stream of w T ater became partly filled with snow and tightly 
 closed by refreezing. Prof. Agassiz describes baignoires in which 
 there is no debris as probably due to the closing up of crevasses. 
 
 “Dust wells” are seen frequently. They are small vertical 
 holes in the surface of the ice, a few’ inches in diameter, and a few’ 
 inches deep with a little dirt at the bottom. At points w’here a 
 small thin patch of dirt lies on the ice this dirt absorbs more heat 
 from the sun than the surrounding ice and causes more rapid melting. 
 Settling of the dirt with the melting of the ice deepens the hole until 
 it reaches the limit of depth to which the sun’s rays can penetrate 
 the cavity. 
 
 The opposite, or protective, effect of rock debris upon the surface 
 of the ice is w ell illustrated by the mound of rock fragments referred 
 to above. This mound, which is 15 or 20 feet high, is probably 
 principally of ice, but is completely covered by the rock fragments. 
 Prof. Chaney 2 mentions such a “surface moraine of yellow slate,” 
 evidently the same rock-covered ice mound, as having been seen by 
 him in 1895. Apparently many years ago a mass of rock fell onto 
 the ice from the cliff at the back of the glacier and with the advance 
 of the ice this has gradually moved forward. Meanwhile the sur¬ 
 rounding ice surface has been lowered by melting while the ice 
 beneath the rock pile has been protected from melting. As the 
 surrounding ice disappeared, rock fragments slid down the sides of 
 the mound so as to cover the ice core. From this mound a belt of 
 scattered drift extends forward like a medial moraine to the front 
 of the glacier. 
 
 1 System Glaciare, 1847, p. 100. 
 
 2 Op. cit., p. 796. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 35 
 
 Excepting at the point of the lobe, the glacier is bordered by a 
 strongly marked marginal moraine 20 to 30 feet in height. At the 
 extremity of the ice tongue the drift has been pushed over the cliff, 
 though at present the ice is a short distance from the crest. One 
 part of this moraine is largely composed of large and small fragments 
 of lava (amygdaloidal trap rock). At a place west of the notch in 
 the divide a bed of this rock extends to the top of the divide and 
 there yields fragments which fall onto the ice. Such lava blocks 
 are scattered all the way across the glacier from the place where 
 these blocks fall to the morame. 
 
 September 6, 1913, the writer attempted some crude measure¬ 
 ments on the rate of movement hi the glacier. On the west margin 
 of the frontal lobe at a point about opposite the curve in the moraine 
 a spike was set at 10.35 a. m. hi the ice 45 inches in advance of a 
 mark placed on the rock ledge. At 4.15 p. m. the distance, as 
 nearly as could be determined, the spike having been slightly dis¬ 
 placed by melting, had increased to 45J inches, an advance of one- 
 eighth inch in 5 hours and 40 minutes. This was at the side of the 
 lobe where it would seem that the movement would be much less 
 rapid than in the center of the stream. 
 
 At a point near the extremity of the narrowed lobe a spike was set 
 at 10.50 a. m. in the ice 37| inches in the rear of a mark on the rock 
 ledge. At 4.03 p. m. this distance had decreased to 37^ inches, 
 indicating an advance of one-eighth inch in 5 hours and 13 minutes. 
 
 Sue Lake and Glacier. —Going westward from Chaney Glacier past 
 the spur of the mountain one finds a beautiful little lake of blue lying 
 in a rock basin in the next scallop of the great cirque. At the head of 
 the lake is a tiny glacier lying at the foot of the great cirque wall. A 
 strongly marked moraine 30 to 40 feet high borders the front of the 
 ice at the edge of the lake, excepting for an interval where a narrow 
 tongue of the ice projects through and into the lake. From this 
 ice small bergs break off and float in the lake. A narrow cliff glacier 
 lies on a bench in the south wall high above the lake. The outlet 
 stream from the lake flows a few rods over rock ledges and then 
 plunges 300 to 400 feet down the cliff to a lower compartment of the 
 great cirque. 
 
 Shepard Glacier. —Crossing the creek which flows from Sue Lake 
 and climbing over the ledges west of the outlet one reaches Shepard 
 Glacier (fig. 21). This glacier was named for E. 11. Shepard, of 
 Minneapolis, who visited this region in company with Prof. L. W. 
 Chaney in 1895 and subsequently. 
 
 This small glacier has an extent from northwest to southeast of 
 about one-half mile and from southwest to northeast of about three- 
 tenths of a mile. It occupies two levels of the cirque, the northern 
 part being divided by a rock cliff. The main part cascades over 
 
36 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 this cliff and in so doing is broken by great yawning crevasses which 
 are closed again in the steeper slope below. 
 
 The front of each of the northern arms of the glacier is bordered by 
 a morainal embankment, for which there is barely room at the tops 
 of the cliffs. At the south side of the main glacier is a moraine piled 
 5 to 25 feet high. In places the ice margin is melted back 50 to 70 
 feet from this moraine. The dirt bands marking the edges of the ice 
 strata show plainly. From the lower ice front a stream of water 
 plunges several hundred feet down the cliff to the lower cirque floor. 
 
 Glacier southeast of Clianey Glacier. —Across the mountain wall on 
 the southeast side of Chaney Glacier is another small glacier poking 
 its nose into a little lake, which lies in a rock basin behind the lip of 
 
 Fig. 21. —Shepard Glacier. 
 
 Photograph by W. C. Alden. 
 
 the upper cirque. When seen by the writer from the top of the 
 cirque wall in August, 1911, this lakelet was dotted with floating 
 masses of ice which had broken off from the glacier front. The 
 water which overflows the lip of the cirque plunges 1,500 feet to a 
 second lake in the head of the valley. 
 
 Former extent of the ice in Belly River Valley. —There are several 
 other small glaciers in the heads of tributaries to the Middle and 
 North Forks of Belly River Valley, last remnants of the great Belly 
 River Glacier. 
 
 From an examination of the valley and of the deposits therein 
 north of the international boundary it is known that at the last stage 
 of the Glacial Period Belly River Valley was occupied by a great 
 glacier extending from the Continental Divide northeastward across 
 the international boundary into southern Alberta, a distance of at 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 37 
 
 least 30 miles (see map facing p. 32). No detailed study of the 
 glacial phenomena has yet been made throughout this valley and its 
 several tributaries, but there is reason for thinking that at a point 3 
 miles south of the forty-ninth parallel, or 10 miles from the Conti¬ 
 nental Divide, the ice in the valley was at least 800 feet thick. 
 
 GLACIERS IN THE NORTHWESTERN PART OF THE PARK. 
 
 Vulture Peak Glaciers .—An interesting area of glaciers and glacial 
 phenomena is accessible either from a camp site in the upper 
 part of Little Kootenai Creek Valley or from one at the head of the 
 South Fork of Valentine Creek. From either site one can reach the 
 top of the ridge between these two valleys by trail and go thence 
 west over the divide. A somewhat more difficult and precarious 
 climb may be made up along the face of the cliffs on either the north 
 or the south side of the lake at the head of Little Kootenai Creek to 
 the notch in the divide, from which the glaciers on the east slope of 
 Vulture Peak are easily reached. The latter courses, however, are 
 hot to be recommended to inexperienced tourists. Between Vulture 
 Peak and the ridge on the east is a considerable bench or rock floor 
 whose relations suggest that it is part of the floor of an old cirque 
 developed by a glacier in the Quartz Creek Valley from which the 
 south wall was cut away by the headward stoping of glaciers which 
 occupied Little Kootenai and Logging Creek Valleys. Three small 
 lakelets occupy basins in this rock floor, and on the mountain slope 
 to the west are the glaciers. The upper and larger one occupies two 
 or more levels. The upper part has a steep surface and is much 
 crevassed, and it extends down to the crest of a cliff and pushes its 
 drift over to fall to the bench below. Farther south a narrow and 
 much crevassed portion of the ice extends down over the cliff to that 
 part of the glacier which spreads out on the bench around to the 
 east. This part extends to the crest of a lower cliff or ledge and 
 thrusts its load of drift over to fall below. The surface, especially 
 near the front, is much broken by transverse and longitudinal crev¬ 
 asses. A morainal embankment extends from the foot of the ledge 
 to the northwest side of the upper lakelet, showing that the ice has 
 been more extensive. Below the south end of the ledge a separate 
 tiny glacier extends down to the water in the upper little lake. The 
 drainage from these glaciers is tributary to Quartz Creek. 
 
 On the ledges just east of this body of ice there is a fine display of 
 the results of glacial abrasion in the form of smoothing, polishing, 
 striating, and grooving (fig. 22). This is to be seen both on northcast¬ 
 dipping rock surfaces and on vertical joint faces. Upward-curving 
 striae show where the ice rode up over ledges which projected in its 
 path. 
 
 Farther south at the foot of the northeast slope of the mountain 
 spur lies another small glacier. This is unique in that the water 
 
38 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 from the northern part escapes across the upturned rock ledges and 
 finds its way to and over the cliff at the head of Little Kootenai 
 Valley, thus being tributary to Hudson Bay. The water from the 
 southern part of the glacier flows southeastward along the strike 
 behind a rock ridge and finally plunges down the cliffs at the head 
 of Logging Creek Valley and becomes tributary to Columbia River 
 and the Pacific Ocean. Because of this relation the proposal has 
 been made to call this Two Ocean Glacier. Striae on the ledges in 
 front of this glacier show that it was formerly larger, and extended 
 southeastward to the saddle between the heads of Little Kootenai 
 
 Fig. 22.—Glacial grooves, Vulture Peak. 
 
 Photograph by M. R. Campbell. 
 
 and Logging Creeks. The southerly trend of striae in this saddle 
 
 Oo O J 
 
 indicates that the ice joined a great Logging Creek glacier. 
 
 From the crest of the southeast spur of Vulture Peak there is a fine 
 view of Vulture Glacier, which lies in an upper cirque in the south 
 side of the mountain mass more than 3,000 feet above the lakes in 
 the head of Logging Creek Valley. From the notch in this creek one 
 can easily reach this glacier. The glacier and neve have a width 
 from southwest to northeast of about four-fifths of a mile and a length 
 from northwest to southeast of about seven-eighths of a mile. From 
 the neve at the back the ice descends with a slope of 15° to 20°, which 
 increases rapidly toward the front where several lobes cascade down 
 over the ledges into notches in the lip of the upper cirque. The total 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 39 
 
 descent from the gaping bergschrund near the top of the neve slope 
 to the end of the lowest lobe is 1,000 feet or more. The surface of 
 the ice is smooth and banded from side to side with soiled zones 
 marking the outcropping of the glacial strata. 
 
 That part of the glacier south of the end of the bifurcating ledge 
 is so broken by crevasses as not to be readily crossed. 
 
 In places there are morainal deposits some distance below the ends 
 of the frontal lobes. One of the small lobes has been considerably 
 larger, as shown by the fact that there is a lateral moraine lying on 
 a bench 50 or 60 feet higher and several rods farther south than the 
 edge of the ice. The front slope of this lobe is about 27°. 
 
 On August 27, 1913, several attempts were made to measure the 
 rate of ice movement. Not far from the end of the main lobe a spike 
 was set in the ice at 2.30 p. m., 26J inches in advance of a mark on 
 the underlying rock. At 3.30 p. m. the distance had increased to 
 26f inches, an advance of one-half inch in one hour. Markers set at 
 the northeast side of the same lobe several hundred feet higher up 
 showed no advance between 2.20 and 3.35 p. m. of the same day, 
 thus indicating retardation of movement at the side of the lobe. 
 Markers set at each side of the ledge which projects through the ice 
 showed no appreciable advance between 1 and 2 p. m. of the same 
 day. Evidently the flow lags about this ledge just as the recurved 
 dirt bands seem to indicate. Near the southeast end of the ledge 
 which bifurcates the glacier, markers were set at 1.30 p. m. on this 
 day, and when reexamined at 2 p. m. the ice had moved one-lialf 
 inch. 
 
 Carter Glaciers .—On the upper slope at the head of Valentine Creek 
 near Jefferson Pass are two small glaciers designated the Carter 
 Glaciers, in honor of the late Senator Carter of Montana. The most 
 southerly one is about one-fourth mile in extent from back to front 
 and about three-fourths of a mile wide from northwest to south¬ 
 east. The surface is smooth and shows but few crevasses. Though 
 so small a glacier, the front is bordered by a morainal embankment 
 rising in places 50 feet above the ice on the inside and 100 feet 
 above the rock on the outside. The ice front has, in part, been melted 
 back 200 feet from the summit of the ridge, but elsewhere it is pressed 
 snugly against the moraine. 
 
 A short distance farther north there is a somewhat larger compound 
 glacier consisting of a lower main body, much crevassed because of 
 the steepness and irregularity of slope, and two distinct smaller ones 
 higher up on the cliff. The upper glacier cascades down to the lower 
 one. Along the north front of this is a strong moraine with reliefs 
 of 60 to 70 feet on the inside and 80 to 100 feet on the outside. At 
 the center of the front the ice thrusts its load of drift over the crest 
 of a 50-foot cliff. The height and position of the moraine on the north 
 
40 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 side indicate that at some time the glacier has had considerably 
 more bulk than it now has. 
 
 On the north slope of Mount Carter is a small glacier more resem¬ 
 bling the valley type in that it extends through the contracted open¬ 
 ing of the cirque and cascades down the steep slope in a long, narrow 
 
 tongue. The ice has shrunken away from its strong lateral moraine. 
 At the front of the cascading tongue the drift is dumped down the 
 steep slope. It is this glacier which furnishes most of the glacial 
 silt which renders so milky the South Branch of Bowman Creek 
 as seen from the trail leading to Brown Pass. 
 
 Photograph Gy M. U. Campbell. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 41 
 
 Rainbow Glacier .—From the mountain ridge east and north of 
 Vulture Peak there is a fine view across the head of Quartz Creek 
 Valley to the Rainbow Glacier nestling in an upper cirque which 
 scallops the mass of Cerulean Eidge on the east flank of Rainbow 
 Peak (fig. 23). 
 
 This glacier and its neve has a breadth from northeast to southwest 
 of nearly 1 mile and a length from northwest to southeast of 1-J- miles. 
 The entire lower half is much crevassed as though it were moving 
 do mi over a steep and irregular slope broken by steps or ledges. The 
 maximum descent of the ice is about 2,000 feet. At about the 
 middle of the front of the glacier a tongue about 100 yards wide 
 extends by cascading down to a ledge about 200 feet below the main 
 front. Excepting in the south part, where a moraine embankment 
 borders the ice, the glacier crowds forward to the very verge of the 
 cliff. The ice in places seems to overhang the edge, and abrupt ice 
 cliffs suggest that great masses of ice break off and are precipitated 
 to the abyss over 2,000 feet below. 
 
 Olson Creek glaciers .—Looking southward from Brown Pass one 
 sees in the great upper cirque a glacier which has a width of nearly 
 seven-eighths of a mile and which descends about 1,200 feet or more 
 in the three-fourths mile of its length. This may be reached by an 
 easy climb of a few hundred feet from the pass. When somewhat 
 larger than it was when seen by the writer in August, 1913, this glacier 
 pushed its terminal moraine near the crest of the cliff which drops to 
 the head of the valley below. Since that time the ice lias shrunken 
 somewdiat from the moraine. More or less detached portions of the 
 glacier lie on benches in the cirque wall above the main mass. Rear 
 the front the ice is broken by crevasses, some of which are 10 to 15 
 feet wide at the top and 15 to 20 feet deep. In the walls of these 
 crevasses the banding of the ice is seen to dip backward upstream at 
 low angle. The ice exposed here carries little or no included drift. 
 At one point where the foot of the glacier is just at the top of a ledge 
 the ice rides free a foot or so above the rock for a distance of at least 
 25 to 30 feet back from the margin. Looking into this space one sees 
 but little drift in the bottom of the ice. Where the ice is grinding 
 polishing, and scoring the rock ledges there appear, so far as can be 
 seen, to be but a thin layer of fine rock flour and small fragments 
 between the clear ice and the rock surface. 
 
 These and other small glaciers in the cirques farther east are the 
 only remnants of the great glacier which during the last great exten¬ 
 sion of the ice occupied Olson Creek Valley and was tributary to the 
 one in Little Kootenai Creek Valley. To this were also tributary 
 the glaciers occupying the head branches of this valley and the val¬ 
 leys of Valentine and Boundary Creeks. It is known that at the last, 
 or Wisconsin, stage of glaciation this great trunk glacier extended 
 northward into southern Alberta. Ten or twelve miles north of the 
 
42 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 boundary line the deposits of this glacier pass under those of the great 
 continental ice sheet. Observations of glacial striae high upon the 
 mountain slopes at the head of Waterton Lake indicate that the ice 
 was at least 1,500 feet thick opposite the mouth of Olson Creek and 
 it was probably even thicker than this. 
 
 Boulder Glacier .—Looking westward from Brown Pass across the 
 great cirque at the head of Bowman Creek Valley, one sees, high up 
 at the top of the great cirque wall, two small glaciers. The larger 
 one of these is Boulder Glacier (fig. 24). This may be reached from 
 the pass, but the route is somewhat hazardous and is not to be recom¬ 
 mended for inexperienced climbers. The bench on which this glacier 
 rests is formed by a lava bed. This rock emerges from beneath the 
 
 Fig. 24.—Boulder Glacier, Kintla Peak in background. 
 
 Thotograph by W. C. Alden. 
 
 eastern margin of the ice and extends thence to the crest of the wall 
 of the lower cirque. In this interval there is a remarkable exhibi¬ 
 tion of the effects of glaciation produced when the ice had a some¬ 
 what greater extent. The ledges are scored with striae and so 
 smoothly rounded and polished as to offer in many places precarious 
 footing (fig. 25). The glacier extends westward through the gap in 
 the mountain crest. The disposition of the zones marking the strati¬ 
 fication and also the general surface slope indicate that the ice now 
 moves toward the cliff on the north side of the gap. For a short dis¬ 
 tance in the midst of the gap there is a strong morainal embankment 
 piled 25 to 35 feet high near the foot of the mountain ridge on the 
 north. This moraine, which is composed of intermingled rock flour 
 and partly worn and partly angular rock fragments ranging in size 
 from a fraction of an inch to 6-foot blocks, is continuous around the 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 43 
 
 west side of the mountain ridge and also about the western part of 
 the glacier. 
 
 Emerging from beneath the western part of the glacier the lava 
 bed extends westward and northward as the floor of two broad gaps 
 until it is cut off at the crests of the walls of two lower cirques in 
 which head branches of Kintla Creek. The surface of this uneven 
 textured, vesicular rock is finely glaciated, exhibiting strke, gouges, 
 and beautifully rounded and polished roches moutonnees. 
 
 Boulder Glacier, together with four tiny glaciers in scallops high 
 up in the walls of the great cirques farther southwest and the cascad¬ 
 ing glacier on the northeast slope of Mount Carter, are the only rem¬ 
 nants of the great glacier which once occupied the vaUey of Bowman 
 
 Fig. 25.—Glaciated lava bed in front of Boulder Glacier. 
 
 Photograph by W. C. Alden. 
 
 Creek and Lake. On the north slope facing the lake, opposite Bain- 
 how Peak, the writer observed horizontal glacial stride evidently pro¬ 
 duced by the great valley glacier 1,100 feet above the lake. The lake 
 opposite tliis point is 150 feet deep, so that it is known that the great 
 valley glacier must have had a thickness of at least 1,200 or 1,300 
 feet opposite Bainbow Peak. 
 
 AGASSIZ AND KINTLA GLACIERS. 
 
 From the mountain slope west of Boulder Glacier one gets a dis¬ 
 tant view of Agassiz Glacier, one of the finest in the park, on the 
 northeast slope of Kintla Peak (fig. 26). This glacier has a breadtli 
 of 1.3 miles. From the broad main part of the mass a narrow 
 tongue extends nearly 1,200 feet lower down the slope. This gives 
 the glacier a length from southwest to northeast of 1.8 miles. The 
 
44 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 ice in this lower tongue is much crevassed. West of this lobe a mo- 
 rainaj embankment borders the ice. Agassiz Glacier has a vertical 
 extent of about 2,000 feet, the lowest point being about 5,800 feet 
 above sea level. The glacier is said to be accessible from Upper 
 Kintla Lake. 
 
 On the opposite, or west, side of Kintla Peak is Kintla Glacier 
 (fig. 27), having a breadth of more than 2 miles, but an area about 
 the same as Agassiz Glacier. 
 
 EARLY GLACIAL HISTORY OF THE REGION. 
 
 Wisconsin stage .—In the above descriptions of the glaciers of the 
 park reference has been made to former greater extension of the ice. 
 
 Fig. 26. —Kintla Peak and Agassiz Glacier. 
 
 Photograph by W. C. Alden. 
 
 The geological studies in and adjacent to the park have developed 
 evidence that there were at least two and possibly three different 
 times when the glaciers extended far down the valleys and out onto 
 the neighboring plains. These extensions of the mountain glaciers 
 were probably contemporaneous with the development and deploy¬ 
 ment of the great ice sheets which covered so large a part of the 
 North American Continent during the several stages of the Glacial 
 Period, or the Great Ice Age. As is the case in the study of the phe¬ 
 nomena of the continental ice sheets, so also the study of Rocky 
 Mountain glaciation has developed evidence showing that the epochs 
 when climatic conditions were such as to cause great extensions of 
 the glaciers alternated with epochs when conditions were similar to 
 those of the present so that the glaciers melted away and the valleys 
 were occupied as now by streams. 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 45 
 
 On the map facing page 32 an attempt lias been made to repre¬ 
 sent graphically conditions as they were in the mountains and on the 
 plains east of the park during the maximum of the last great stage, 
 known as the Wisconsin stage, of glaciation. On this map the moun¬ 
 tain valleys are shown filled with ice 1,500 to 2,500 feet thick, the 
 
 
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 HH 
 
 P 
 
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 r\» 
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 M 
 
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 hH 
 
 r- 
 
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 glaciers heading in the many cirques and extending thence down the 
 valleys and out onto the plains. The crests of the dividing mountain 
 ridges are represented as bare, although they were probably hi reality 
 more or less mantled with snow and ice. The map shows the general 
 relations of the mountain glaciers to the border of the great Keewatin 
 glacier which centered on the Keewatin plateau west of Hudson 
 
46 
 
 GLACIERS OF GLACIER NATIONAL PARK. 
 
 Bay, and also the temporary lake, Cut Bank glacial lake, which re¬ 
 sulted from the blocking of Cut Bank Creek by the ice. 
 
 Streams of ice heading in the mountain valleys now drained by 
 Two Medicine and Badger Creeks and their tributaries coalesced and 
 spread out on the plain as a great piedmont glacier, known to geolo¬ 
 gists as the Two Medicine glacier. This glacier had a maximum 
 length of about 48 miles and a breadth of 30 miles. The knolled and 
 pitted surface of its morainal deposits may be seen between the rail¬ 
 way and the flat-topped ridge 5 miles north of Glacier Park station. 
 North of this, ice in Lake Creek Valley coalesced with a glacier in 
 Cut Bank Valley. Morainal deposits of these glaciers are crossed by 
 the automobile road leading from Glacier Park station to St. Mary 
 Lakes. 
 
 St. Mary Valley was occupied by a great trunk glacier which so 
 nearly filled the valley where the lakes now lie that it deposited a 
 well-marked lateral moraine at the top of the ridge on the east 1,200 
 foot or more above the lower lake. So effectually did this ridge serve 
 as a diverting dam that the greater glacier, instead of extending 
 directly eastward onto the plains, was turned northward into south¬ 
 ern Alberta. Where the ridge is lower, east of Babb, the ice did 
 extend onto the upland, and a lobe deposited a strongly marked 
 moraine, enclosing the basins of Duck and Goose Lakes. In St. 
 Mary Valley about 1 mile south of the boundary the drift of the 
 St. Mary Glacier, which is composed entirely of material from the 
 mountains, is overlapped by drift of the continental, or Keewatin, 
 glacier, which contains granite boulders from the region of Hudson 
 Bay. Tributary to St. Mary Glacier were glaciers in the valleys of 
 Kennedy, Swiftcurrent, Boulder, Bed Eagle, and Divide Creek Val¬ 
 ievs. 
 
 Drift of the glaciers which at the same time occupied Belly Kiver 
 and Waterton Lakes valleys is also overlapped by drift of the conti¬ 
 nental glacier, in the one valley about 9 miles and in the other about 
 12 miles north of the international boundary. 
 
 The phenomena in the western part of the park indicate that the 
 valleys of Kintla, Bowman, Quartz, Anaconda, Dutch, and Camas 
 Creeks and those farther south were also occupied by great valley 
 glaciers during the Wisconsin stage of glaciation. The actual ex¬ 
 tent of these glaciers has, however, not yet been fully determined. 
 Terminal moraines have been found in Bowman, Quartz, and Ana¬ 
 conda Creek valleys, but it has not been determined that those seen 
 farthest downstream mark the limit of extension of the glaciers at 
 the Wisconsin stage. The best examples of these deposits are the 
 moraines crossed by the trail below Bowman Lake and above and 
 below Middle Quartz Lake. 
 
 The great intramontane basin which is represented by West Flat- 
 top, Flattop, and Granite Park and similar tracts, and into the bot- 
 
GLACIERS OF GLACIER NATIONAL PARK. 
 
 47 
 
 tom of which are cut the valleys of McDonald and Mineral Creeks, 
 is believed to have been occupied by a great central mass of ice 
 which discharged principally southwestward by the McDonald 
 Creek Valley. 
 
 To this stage of glaciation was probably due some deepening of 
 the previously-existing stream-cut valleys and the broadening and 
 smoothing of sharp V-shaped cross profiles, produced by stream 
 erosion, to the wider and beautifully rounded U-shaped profiles 
 now seen (fig. 1, A and B). Also most of the excavation of the 
 remarkable cirques which scallop the slopes of the great mountain 
 masses was accomplished at this stage. 
 
 Pre- Wisconsin glaciation .—The Wisconsin stage of glaciation was 
 preceded by a long period during which the glaciers were probably 
 absent or much reduced in size, a time during which the streams 
 were actively engaged in sculpturing the great mountain mass, in 
 deepening the valleys, and in eroding and washing away the soft 
 rocks underlying the adjacent plains. 
 
 Prior to this period of valley cutting, the plains bordering the 
 mountains on the east were in general some hundreds of feet higher 
 than at present and not so much broken by hills and valleys. In 
 the area between the Great Northern Railway and the international 
 boundary there are numerous remnants of the former high levels of 
 the plains. These are the flat tops of the ridges which stand between 
 the several branches of Milk River, St. Mary River, and Cut Bank 
 Creek (the stippled tracts shown on the map facing page 32). Ex¬ 
 amination of the deposits which underlie these flat tops and which 
 overlie the upturned and beveled edges of the sandstones and shales 
 forming the bulk of the ridges shows that a large part at least are of 
 glacial drift derived from the mountains. The relations show that 
 long ago, before the valleys which now separate these ridges were 
 eroded and when the various remnants yet formed a continuous, 
 nearly flat plain, there was a stage of glaciation when the ice heading 
 in St. Mary Valley and the tributary valleys was not diverted north¬ 
 ward by St. Mary Ridge and the great trough in which the St. Mary 
 lakes and river now lie, but that the tributary glaciers united in a 
 great piedmont glacier, which spread directly eastward onto the 
 uneroded plain. Ice from Cut Bank and Two Medicine Valleys 
 probably also joined in this extension. Over a large area south of 
 the railway, however, no remnants of these early glacial deposits 
 have been found. They were probably almost entirely removed 
 during the long interval when stream erosion was going on or were 
 obscured by being overrun by the great Two Medicine glacier of the 
 Wisconsin stage. 
 
 In places, as, for instance, on the ridge north of Lower Two Medi¬ 
 cine Lake and on St. Mary Ridge, the long exposure of this old drift 
 
48 
 
 GLACIERS OF GLACIER NATIONAL 
 
 J. n.uxx, 
 
 3 0112 072879023 
 
 to the weather has resulted in the limestone pebbles and bowlder; 
 being removed from the upper part by solution and the calcium car 
 bonate being carried down by the percolating waters and deposite 
 as a cement, binding the lower part of the drift into a hard con 
 glomerate. 
 
 The relatively great age of this early glacial drift may be inferred 
 from the fact that even those tributaries of Milk River which received 
 none of the mountain water have cut valleys several miles in widtf 
 and hundreds of feet deep below the horizon of the former high-level 
 drift-covered plains. It is believed that St. Mary Valley was deep 
 ened at least S00 or 1,000 feet during the interval between the earlie 
 and the Wisconsin stages of glaciation, that the tributary mountai 
 gorges and other valleys were correspondingly eroded, and that a| 
 considerable part of the sculpturing of the great mountain mass wa 
 accomplished during this period of stream activity. Compared wit 
 the time which has elapsed since the Wisconsin stage of glaciatio 
 the interval of deglaciation must have been very long. 
 
 In the above discussion the pre-Wisconsin interval has bee 
 referred to as a single uninterrupted epoch of deglaciation and ero 
 sion. There is, however, definite evidence that it was not such 
 There are, east of the mountains in the Blackfeet Indian Reservation 
 remnants of three sets of plains above the levels of the present drain 
 age lines, all of these older than the drift of the Wisconsin stage o 
 glaciation, and on two of these are deposits of pre-Wisconsin glacia 
 drift. The third set of these plains comprises the broad valley bot 
 toms, onto which the glaciers of the Wisconsin stage encroached an 
 into which the present streams have cut their sharp narrow channels 
 
 It is thus probable that there were two distinct earlier stages o 
 glaciation of the mountains separated from each other and from th 
 Wisconsin stage by long intervals of deglaciation and stream erosion 
 Some of these stages may have resulted from or have been accom 
 panied by general elevation or depression of the region. 
 
 Within the limits of this brief paper there is not opportunity t 
 discuss all the evidence bearing on this question. For furthe 
 details reference should be made to other papers by the presen 
 writer and others . 1 
 
 i Pre-Wisconsin glacial drift in the region of Glacier National Park, Mont., by Wm. C. Alden, BullJ 
 Geol. Soc. Am., vol. 23, pp. 687-708, 1912. 
 
 Ditto, by Wm. C. Alden and Eugene Stebinger, Bull. Geol. Soc. Am., vol. 24, pp. 529-572, 1913. 
 
 The Montana lobe of the Keewatin ice sheet, by F. II. II. Calhoun, Prof. Paper U. S. Geol. Survey, NoJ 
 50, 1906. 
 
 lip;? 
 
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