136 GEOLOGICAL SURVEY OF THE TERRITORIES. 



The hot-spring area extends about five miles along the lake shore, and 

 is about two miles wide. Steam Point has been, at one time, covered 

 with very active springs, but now they are fast becoming extinct. Two 

 steam-vents are now in operation, sending forth steam with a noise 

 like that of the escape-pipe of a steamboat. A number of small sim- 

 mering springs are scattered around these vents. There is here a thick- 

 ness of 200 feet of conglomerate, which is made up largely of hot-spring 

 deposits. The lake seems to have beaten against the shore, and worn 

 away a large portion, leaving a bluff wall 50 feet high above water-level. 

 A large mass of the conglomerate has been cut off by the waves, and 

 left in the lake 100 feet from the bluff' shore. South of Steam Point, 

 on the shore of the lake, are about twenty or thirty springs of various 

 temperatures, from llOo to 192^. Some are quiet, some bubbling quite 

 briskly, and others are true boiling springs. The little steam-vents are 

 lined with sulphur. About a mile east of the point, around a little lake, 

 there is an extensive group of springs. The ground is covered with 

 sulphur, alum, common salt, &c., tinged with oxide of iron. Thick de- 

 posits of silica, often tinged with oxide of iron or sulphur, attest the 

 former existence of a much larger system of springs than we find here 

 at the present time. At one point, in the bed of the little creek that 

 flows into the small lake, which is 10 feet wide and 2 feet deep, there is 

 a large spring that boils up very fiercely, and yet the temperature is not 

 above that of the water of the creek itself. The agitation of the water 

 must be due to the escape of gas alone. At Steamboat Point, and around 

 the little lake, the ground is in i)laces perforated, like a cullender, with the 

 little simmering vents, which denote, I think, the last stages of a system 

 of larger springs. 



Proceeding southward along the shore of the lake, we meet with 

 the springs and steam-vents, in greater or less numbers, scattered 

 along the shore — 186°, 183°, 185°, 178° will, perhaps, give the aver- 

 age temperatures — all quiet, bubbling, or boiling springs. 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. In 

 the valley near Pelican Creek, a few springs are issuing from beneath 

 the crust, distributing their waters over the bottom, and depositing the 

 oxide of iron, sulphur, and silica, forming the most beautiful blending 

 of gay colors. Although the waters of the springs are 160°, yet the 

 channels are lined with a thick growth of mosses and other plants, and in 

 the water is an abundance of vividly green algous vegetation. The great 

 mass of hot-spring material built up here cannot be less than 400 feet 

 in thickness. A large portion of it is pudding-stone and conglomerate. 

 Some of the rounded masses inclosed in the fine white siliceous cement 

 are themselves pure white silica, and are eight 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 j)eriod not very remote ; 

 that the steam-vents, which are very numerous, are only the dying 

 stages. These vents or chimneys are most richly adorned with brilliant 

 yellow sulphur, sometimes a hard amorphous coating, and sometimes 

 in delicate crystals that vanish like frost-work at the touch. It seems 

 that it is during the last stages of these springs that they adorn them- 

 selves with their brilliant and vivid colors. 



We will now bid farewell to this remarkable lake-basin, and, taking a 



