PEALE.] YELLOWSTONE LAKE SULPHUR HILLS. 113 



In the report of the survey for 1872 Professor Bradley says : 



The first map which, so far as known, represents the lake with anything like its true 

 form is a manuscript one by Jedediah S. Smith, who hunted thiough the mountains 

 from California to the British Possessions during the years from 1821 to 1830. The 

 original was purchased in Oregon for the War Department, hut is supposed to have 

 never reached Washington. A copy taken in 1853 exists in the hands of Mr. George 

 Gibbs, of New Haven, Conn. 



The present lake is the remnant of one that formerly extended over a 

 much larger area, and which had a more regular shape, the arms to the 

 southeast being then merged in the main body. One extension also 

 occupied what is now called Hayden's Valley. 



The water of the lake is always cold, averaging about 60° F,, and has 

 frequently quite a strong surf dashing on its beach, a strong westerly 

 wind usually ruffling its surface in the afternoons. The surrounding 

 rocks are mainly volcanic, rhyolites predominating. On the immediate 

 confines of the lake the lacustrine formations deposited by the old lake 

 are found. 



On the west, southwest, and south the country is plateau-like, and the 

 divide or watershed between Yellowstone Lake and the Shoshone Lake 

 is only 300 feet above the level of the former. On the east is the 

 Yellowstone Eange, whose peaks rise from 2,000 to 3,500 feet above the 

 lake. This range, with the mountains southeast of the lake, form the 

 impassable ("?) barrier that prevented Boiieville in 1833 and Raynolds 

 in 1860 from reaching the lake. It can, however, be crossed in two 

 places at least, as was proved by Captain Jones's expedition of 1873, viz, 

 from the head of Wind Eiver to the Upper Yellowstone Kiver, and from 

 the head of the Stinking- Water Eiver to the head of Pelican Creek. 

 The springs on the margia of the lake are comparatively inactive, those 

 of the west being the most important. 



SULPHITE HILLS, 



This name has been somewhat inappropriately given to a mass of old 

 spring deposits on the north side of the lake, which are made up mainly 

 of silicious materials, although sulphur is present in small quantity. I 

 have never visited the hills, and therefore present the descriptions of 

 those who have visited them. Dr. Hayden, in 1871, writes of the local- 

 ity as follows : 



Sulphur Hills, on the north side of the lake, is another of the magnificent ruins, of 

 ■which only a few steam vents now remain. The deposit, however, is a large one, 

 and covers the side of the mountain for an elevation of 600 feet along the lake shore, 

 the huge white mass of silica covering an area of about half a mile square, and can be 

 seen from any position on the lake shore, and appears in the distance like a huge bank 

 of snow. 



The great mass of hot-spring material btult up here cannot be less than 4C0 feet in 

 thickness. A large i)ortion of it is pudding-stone and conglomerate. Some of the 

 rounded masses inclosed in the fine, white silicious current are themselves pure white 

 silica, and are 8 inches in diameter. It is plain, from the evidence still remaining, 

 that this old ruin has been the theater of tremendous geyser action at some period not 

 very remote ; that the steam vents, which are very numerous, are only the dying 

 stages. These vents or chimneys arc most richly adorned with brilliant yellow sul- 

 phur, sometimes a hard amorphous coating, and sometimes in delicate crystals, that 

 vanish like frostwork at the touch. It seems that it is during the last stages of these 

 springs that they adorn themselves with their brilliant and vivid colors.* 



Professor Comstock, writing of this locality, says : 



At this point there are three deep basins or hollows between ridges of the old 

 spring deposits, in each of which there is a small group of springs. From the west 



* Eeport U. S. Geol. Surv. of the Terr, for 1871, 1872, p. 136. 

 8 H, PT II 



