114 REPOET UNITED STATES GEOLOGICAL SUEVEY. 



Bide a powerful stream has issued at one time, draining off the surplus "water Toy a series 

 of interesting cascades. Throughout the whole section hetween this spot and Green 

 Spring [on Pelican Creek] there has been, during a recent geological period, and 

 probably within the historical epoch, a degree of activity greater than is at present 

 manifested anywhere in this vicinity ; and yet it does not appear that the existing 

 phenomena are materially less than they have been for very many years * * * The 

 history of the accumulation of the extensive deposits, here forming a mass several 

 square miles in area and fully 200 feet in thickness, is not to be read in an hour, but 

 it will require the patient labor of years to unravel the intricate problems which 

 arise even Avhile viewing hastily a single section like this, which is but one of the lesser 

 of a hundred of this nature * * * Thesnow-whiteaspectof the hills, which enables 

 them to be distinguished from a great distance, is due to the silica which forms the 

 great bulk of the deposit. Sulphur exists in broken masses, mostly amorphous, with 

 some sublimated crystals about the active springs. Occasional brick-red spots are 

 visible, caused by the presence of iron. The mass of the siiicious deposit is a fairly 

 compacted white rock, fine grained, and much jointed ; but there is much of a very 

 beautiful tough quartzite, with a conchoidal fracture, and having a pearly luster, or 

 it is sometimes iridescent in a favorable light. 



Between 12 m, and 1 p. m. of the 4th of August a heavy cloud of vapor Was ob- 

 served ascending from this spot while passing along our main trail, one mile distant. 

 I visited the locality about 2 o'clock in the afternoon of August 7, and also had 

 several other good opportunities of observing such emission, if it had occurred, but 

 not neai" midday. Had I not seen it I could not have believed it possible for such a 

 quantity to be emitted by such a small number of apparently unimportant springs aa 

 were afterward found to occupy this section. Judging from this accidental circum- 

 stance, it may not be unfair to suppose that these fumeroles are periodically agitated, 

 though nothing can be predicated concerning the regularity of the action, nor the 

 duration of the quiescent intervals.* 



TURBID LAKE GROUP. 



Turbid Lake is a small, heart-shaped body of water, about a half mile 

 long by a quarter of a mile in width, and was named from the muddi- 

 ness of its water, through which sulphurou* gases bubble constautly 

 It is back of Steamboat Point, about 2 miles from the lake. Two small 

 streams flow into it, and the region bordering the lake, near the en- 

 trance of the one from the east, is the seat of quite a number of im- 

 portant springs. These were first visited in 1871, while we were in camp 

 at Steamboat Point. 



The lake is 400 or 500 feet above the level of Yellowstone Lake, and 

 has a temperature of 60° or G5°. It tastes strongly of alum. 



On the south side of the mouth of the creek from the east the princi- 

 pal springs are located. They are of all sizes and descriptions; some 

 have raised vents and others are turbid springs. The surface is per- 

 forated like a colander, with simmering vents from a few inches in 

 diameter to several feet. The temperatures here were as follows : Sul- 

 phur Mud Spring, 178° ¥.-, White Turbid Spring, 190° F.; Turbid 

 Springs, 176° F., 190° F., 182° F., 176° F., and 190° F. Back of these 

 the side of the hill was composed of sulphur, alum, and clay deposits, 

 which made unsafe footing, a step being apt to cause a new spring to 

 burst forth. In the bed of the creek, east of these springs just described, 

 is the most powerful spring in the group. It is 10 feet wide and 2 feet 

 deep, and boils up furiously. Although the water is milky, the tem- 

 perature is not greater than in the creek above and below the spring. 

 Farther down the creek, below the sulx^hur vents and mud springs, were 

 two more, close to the stream, having a temperature of 186° F. On the 

 north side of the creek are several muddy springs. One of these is 

 black (sulphide of iron?) and the other white. Suli)hur is abundant in 

 the deposits near them. The black spring is about 30 feet in diameter, 

 and the muddy water has a strong alum taste. 



* Report of Reconiiaissance of Northwestern Wyoming, by Capt. W. A. Jones, in 

 1873, pp. 194, 195. 



