GEOLOGICAL SURVEY OF THE TERRITORIES. 89 



engine, and hence its name of Locomotive Jet. The aperture is about 

 6 inches in diameter, a sort of raised chimney, and all around it were 

 numerous small continuous steam-vents, all of which were elegantly 

 lined with the bright-yellow sulphur. The entire surface was covered 

 with the white siliceous crust, which gives forth a hollow sound beneath 

 the tread ; and we took pleasure in breaking it up in the vicinity of the 

 vents, and exposing the wonderful beauty of the sulphur-coating on the 

 inner sides. This crust is ever hot, and yet so firm that we could walk 

 over it anywhere. On the south side of these hills, close to the foot, is 

 a magnificent sulphur-spring. The deposits around it are silica j but 

 some places are white, and enameled like the finest porftelain. The thin 

 edges of the nearly circular rim extend over the waters of the basin 

 several feet, yet the open portion is 15 feet in diameter. The water is in 

 a constant state of agitation. The steam that issues from this spring is so 

 strong and hot that it was only on the windward side that I could ap- 

 proach it and ascertain its temperature, 197°. The agitation seemed to 

 affect the entire mass, carrying it up impulsively to the height of 4 feet. 

 It may be compared to a huge caldron of perfectly clear water some- 

 what superheated. But it is the decorations about this spring that lent 

 the charm, after our astonishment at the seething mass before us — the 

 most beautiful scolloping around the rim, and the inner and outer sur- 

 face covered with a sort of pearl-like bead work. The base is the pure 

 white silica, while the sulphur gave every possible shade, from yellow to 

 the most delicate cream. I^o kind of embroidering that human art can 

 conceive or fashion could equal this specimen of the cunmng skill of na- 

 ture. On the northeast side of the hills, extending from their summits, 

 are large numbers of the steam-vents, with the sulphur linings and de- 

 posits of the sulphur over the surface. These hills are entirely due to 

 the old hot springs, and are from 50 to 150 feet in height. The rock 

 is mostly compact silica, but there is almost every degree of purity, from 

 a kind of basalt to the snow-white silica. Some of it is a real conglom- 

 erate, with a fine siliceous cement inclosing pebbles of white silica, like 

 those seen around the craters of some geysers. Although at the pres- 

 ent time there are no true geysers in this group, the evidence is clear 

 that these were, in former times, very powerful ones, that have built up 

 mountains of silica by their overflow. The steam-vents on the side and 

 at the foot of these hills represent the dying stages of this once most 

 active group. Quite a dense growth of pines now covers these hills. 

 They rise up in the midst of the plains, and from their peculiar white 

 appearance are conspicuous for a great distance. At one point there is 

 a steam-vent so hot that it is difticult to approach it, emitting a strong 

 sulphurous smell, and within two feet of it there is a larger spring, boil- 

 ing like a caldron. So far as I can determine, there is no underground 

 connection of any of the springs with each other. Sometimes the rims 

 of these craters, as well as the inner sides of their basins, have a 

 beautiful papulose surface, the silica just covered with a thin veil of 

 delicate creamy sulphur. At this locality are some very renuirkable 

 turbid and mud springs, on the south portion of this singular group, 

 as can be seen by reference to the chart. One of them has a basin 20 

 feet in diameter, nearly circular in form, and the contents have almost 

 the consistency of thick hasty-pudding. Tlie surface i.s covered all over 

 with puffs of mud, which, as they burst, give off a thud-like noise, and 

 then the tine mud recedes from the center of the puiTs in the nu)st per- 

 fect rings to the side. This nuul-pot i)resents this beautiihl picture ; 

 and although there are hundreds of them, yet it is very rare that the 

 mud is just in the condition to admit of these peculiar rings. The kind 



