HiYDEX.J GEOLOGY MOKAIXAL DEPOSITS. 57 



terrace, as it may be called, is very irregular, varying from 20 to 80 or 

 100 feet above the valley, and is full of irregular depressions like small 

 lake-basins, but without any apparent outlet. Fragments of glaciers 

 must have remained in this place which melting away, formed reservoirs 

 of water, which finally dried up, the morainal matter accumulating all 

 around them. Sometimes these depressions are oblong and tortuous like 

 the old bed of a stream, and continue for a mile or so, and then close up 

 in a sort of pocket. The surface is covered all over with worn bowlders 

 of granite of various sizes, sometimes 20 or 30 feet in diameter. When 

 streams have cut through it so that sections can be seen, which is not 

 common, it appears to be composed of rather fine earth, evidently the 

 result of the grinding of the granite rocks by ice, and more or less 

 rounded granitic masses of all sizes from a small pebble to a mass of 

 many tons' weight. The position of the morainal deposits would indi- 

 cate that on the west side of the range also there was, during the glacial 

 period, a vast mass of snow and ice filling up the open valley and run- 

 ning up the gorge like valleys on either side. The valley of Taylor's 

 Creek, which will average a mile in width, is covered over with isolated 

 morainal mounds or ridges, never more than 50 feet high. The enor- 

 mous accumulation of the morainal matter on the west side of the range 

 would seem to show that the great body of the glacier was there, though 

 extending far westward are abundant signs of glacial action. 



We shall speak of this subject again in describing the Mount of the 

 Holy Cross and its surroundings. Far to the south, looking down tlie 

 broad, open vallej^ of the Gunnison Eiver, we can see the modern lake- 

 deposits much eroded near the junction with the Grand Eiver. Still 

 farther southward is the Uncompaghre range dimly seen on the horizon. 

 To the west is a portion of the Elk range, with the wonderful mass of 

 red rock and the great group of sharp peaks, which show a remarkable 

 chaos of strata. To the northwest are the sources of the Gunnison, with 

 the rounded granite mountains which have been so distinctly glaciated. 

 Here and there the stratified rocks may be seen resting on the granites, 

 and inclining at different angles. To the north is a wilderness ck peaks, 

 which form the Sawatch range, some capped with, igneous rocks, others 

 projecting their ragged, sharp, granitic points or crests high up among 

 the snows, 14,000 feet and upward. The quite irregular ranges of 

 mountains on the west side of the Gunnison show most clearly that they 

 are subordinate portions of the great anticlinal we have been describing. 

 The abrupt side or face is toward the east, while on the west side the 

 slopes are usually gentle, and whenever the sedimentary beds occur they 

 incliuQ toward the west. The basis rock of the Gunnison Valley, under- 

 neath the great thickness of morainal detritus, is granitic, resembling 

 very closely the granite rocks of Salt Lake Valley, Utah. The gray 

 granitic rocks are full of black, apparently rounded masses, as seen in 

 Cottonwood Caiion, which indicates that they were originally conglom- 

 erates, so changed by metamorphosis that only indistinct traces of the 

 included bowlders are now visible. 



The irregular range west of the Sawatcli is undoubtedly, as I have 

 before stated, a subordinate portion of the anticlinal on the west side. 

 Fragments of the great mass of sedimentary rocks can be found at differ- 

 ent elevations, especially on the west side, though the granite rocks pre- 

 dominate. About four miles up one of the small side-valleys of Taylor's 

 Creek, to the west, we find low down in the bottom a patch of massive 

 dark-blue carboniferous limestone with corals and stems of crinoids. 

 Some of the layers are made up of fragments of organic forms. The 

 whole is about 50 feet in thickness, inclining west 12°. It is simply a 



