GEOLOGICAL SURVEY OF THE TERRITORIES. 243 



S'lpply apparently comes from the flow of the numerous small ponds 

 amouo- the hills before mentioned. 



Showers for two days had softened the soil so much that portions of 

 ground immediately about the springs, which are perfectly safe in dry 

 weather, were now too soft for passage, often letting one down a foot or 

 so, and that, too, in places where at that depth one was likely to find 

 scaldiiig-hot mud. Fortunately, no serious accidents occurred. 



After a short interval of timber, another small meadow-like basin 

 opens to view, occupied by a few small warm springs of no importance. 

 Again the mountains close in ; so that the stream flows for nearly a 

 mile through a narrow rocky caiion, with sharp ridges rising from 1,000 

 to 1,200 feet high on either side, down whose almost precii)itous elopes 

 beautiful cascades rushed to the river. The banks are mostly composed 

 of obsidian sandstone in tumbling masses ; so that I had great difficulty 

 in leading my horse through it, while the train was obliged to climb 

 over the bounding ridge on the east. The strata are mostlj^ upturned 

 at various angles through the caiion, but become more nearly horizontal 

 at its upper end, where we approach the level of the last flat basin 

 about the head of the river. Sir. Bechler reports a large amphitheater, 

 resembling a crater, passed by the train as it reached the top of the 

 ridge on the east side of the caQon. 



The basin surrounding the head of the river is occupied by quite a 

 large meadow, tolerably dry in the middle, where the stream winds 

 along, but very swampy all around its borders, where numerous cold 

 springs escape from the rocky hills. The sites of a few old hot springs, 

 long since extinct, are marked by patches of the much-disintegrated 

 white geyserite, now mostly buried under the tall grasses and sedges 

 which cover the meadow. A small lake, covering perhaps sixty acres, 

 occupies the southern end of the valley, where it bends to the eastward; 

 and, as the ultimate lake-source of the Madison Eiver, is the only proper 

 possessor of the name Madison Lake, which has heretolore been applied 

 by the hunters to a large sheet of water upon the other side of the 

 divide, under the mistaken idea that it was the head of this river. The 

 lake once occupied the entire extent of the basin, having then covered 

 a curving area about two miles long by about a half mile wide, but has 

 been mostly drained by the erosion of the last caiion. The terrace- 

 borders of the old lake are faintly indicated at some points, but not so 

 plainly that their elevation could be definitely determined. The present 

 border of the timber, from 20 to 30 feet above the stream, in the lower 

 part of the basin, marks the lowest level at which the lake stood for 

 any considerable time. Though the basin receives only three small 

 brooks, supplied by the banks of snow which constantly rest upon 

 portions of the divide, yet the main stream, where it leaves the basin, 

 carries a good body of water, mostly supplied by the large springs 

 already mentioned. Some of these are large pools, from 10 to 20 feet 

 across, with a strong flow of water boiling up from b-^neath, sometimes 

 through quicksand, sometimes through numerous large openings in the 

 stiff clay bottom. 



A storm of mingled snow, sleet, and rain detained us here for one day, 

 Sei)teraber .5; but next morning it cleared, the snow rapidly melted, 

 and we went on. Our hunter, Frank Mounts, had reported a valley 

 about two miles south of us, through which a stream flowed westward. 

 Accordingly, while the train moved about three miles nearly due east, 

 to a new camp on Shoshone Lake, Mr. Bechler and I crossed the south- 

 ern divide to the head of the newly-reported river. We found it to be a 

 large stream, formed, within a short distance, from the abundant flow of 



