128 GEOLOGICAL SUKVEY OF THE TEERITORIES. 



and silicified. Imbedded iu the rock we find numerous cylindrical 

 masses of chalcedony a foot and more in diameter. In some of these 

 masses we can still trace the form of the woody libers, while others 

 have bits of silicified wood that has not been changed to chalcedony. 

 In the center of many of these cylinders we find crystals of amethyst. 

 They are large and have a fine color. If we had been able to penetrate 

 to a greater depth there is no doubt but that we would have found still 

 handsomer specimens. In other si)€cimens the wood seems to have 

 formed a nucleus around which the quartz has crystallized, chalcedony 

 forming the center and milky quartz the exterior. In one place on this 

 hill I found a great variety of jaspers, with also agates and semi-opal. 



The following is a complete list of the minerals found at this locality : 

 Amethyst, (amethystine quartz,) limpid quartz, milky quartz, (ferruginous 

 quartz,) chalcedony, carneliau, chrysoprase, prase, banded agate, liiut, 

 red, yellow, gray, blue, and black jas3)ers, semi-opal, and calcite. 



The calcite is found in the center of agate-geodes. The jaspers are 

 very fine, containing three and four colors in some of the pieces. The 

 crystals of quartz and amethyst are all large and fine. 



Throughout the entire valley of the Yellowstone qunrtz, chalcedony, 

 agate, and obsidian-chips are common, while almost all the trachytes 

 contain crystals of sanidine. Among the specimens brought from 

 Clarke's Fork were argentiferous galena ; and the blue and green car- 

 bonates of copper from the Clarke's Fork mines. 



We left Elk Creek on the 4:th of August, and made our next camp at 

 the foot of Mount Washburne, on the eastern side, in a small, densely- 

 timbered valley bordering the Grand Caiion. Close to our camp there 

 was a small gulley containing some springs, of which I recorded the 

 temperatures. A small stream ran through the gulley, aud throughout 

 the entire bed there were springs whose i)resence was revealed by the 

 bubbling of carbonic acid and sulphuretted hydrogen through the water. 

 On either side of the stream there are abundant dejiosits, of a white 

 color, containing lime, silica, and sulphur, giving evidence that at some 

 past time this place was the seat of a large group of active springs, of 

 which those now existing are a mere trace. It may not be many years 

 before they will be entirely extinct. The specific description of these 

 springs is as follows : No. 1 is eight feet by five, aud gave off' sulphuretted 

 hydrogen abundantly. The temperature was only 52° F. No. 2 is 

 three by four feet, and has a temperature of 53° F. ISTos. 4 and 5 were 

 merely small holes in the deposit on the bank of the stream. The tem- 

 perature of the former was di° F. and that of the latter 115° F. The 

 remaining springs were as follows : No. 6. 188° F. ; No. 7, J 88° F. ; and 

 No. 8, l'JO° F. The boiling-point here would be 1980.3 F. The tem- 

 perature of the air during these observations was 7G° F., the time being 

 about 7.30 a. ni. The elevation above sea-level was 8,117 feet. From 

 this group of springs we caught a glimpse of a white spot through the 

 trees, which indicated that there were more springs to the north of 

 these. Toward this place we turned our heads, and while riding along 

 through the woods we came to a pool of water which would measure 

 probably thirty yards by fifty. The surface of the water was almost all 

 iu agitation from the number of points of evolution of carburetted 

 hydrogen. Tlie temperature of the water was only 54° F., while the 

 air still remained at 70° F. This i)ool was on about the same level as 

 the springs mentioned above. A short ride from this pool brought us to 

 the spot we were seeking, and we found ourselves iu the midst of an 

 active group of mud springs or salses. The springs are distributed over 

 the side of a hill which steams from top to bottom. It was a most hor- 



