GEOLOGICAL SUEVEY OF THE TEKEITOEIES. 103 



alkali flat. The springs which issue from the base of the mountains on 

 either side cause the bottom to be marshy or boggy, in many places 

 rendering the traveling difficult. The plateau ridges which wall the 

 valley in on either side rise to the height of 1,000 to 1,200 feet, and are 

 covered with a de"hse growth of pines, not large, seldom more than 24 

 to 30 inches in diameter, averaging not more than 10 inches, but rising 

 as straight as an arrow to the height of 100 to 150 feet, and growing 

 so thickly together that it was with great difficulty we could pass among 

 them with our pack-animals. 



Among the foot-hills on the south side of the East Fork, about two 

 miles above our camp, we found quite an interesting group of springs 

 in a more or less active state. The basis material of the deposit is the 

 silica, snowy white; but here and there, are quite extensive deposits of 

 sulphur. All the steam vents are lined with sulphur, and the little 

 streams which flow along tbe valley with, the aggregated waters are lined 

 witb the silica, or tinged with the most delicate cream color. There are 

 perhaps thirty or forty springs in this group. I will note a few of them : 

 1. A sulpbur spring, 128°. 2. Boiling spring with a circular basin 5 feet 

 in diameter, 172°. 3. An impulsive spring that rises and falls about once 

 a second with a jerking noise, 192°. 4. Throws out quite a stream 

 of w^ater, 12 inches wide and 2 inches deep ; the basin and channel 

 are most delicately lined with sulphur, 182°. 5. A boiling sulphur 

 spring, 189°. 6. A boiling spring, 199°. 7. 183°. There are a great 

 number of steam vents with the orifices lined with sulphur. Underneath 

 the crust also are found crystals of sulphur of a vivid yellow. We were 

 not able to explore this stream to its source in the high plateau, but 

 there are undoubtedly many of these groups of springs which we did 

 not see. We followed the valley down to the Fire-Hole Basin, about six 

 miles, and found scattering springs all the way. At one point we found 

 the temperature of the water of the creek 76°. It was remarkably clear, 

 but it was insii^id, like ordinary water that has been boiled. ]3ut the 

 abundance as well as the luxuriance of the vegetation in and around the 

 stream was almost marvelous. 



About two miles below our first camp, we passed a pretty little stream 

 flowing down from the hills, with the channel lined with a delicate veil 

 of creamy sulphur. We followed it up the valley a half a mile and came 

 to another group of springs similar to those just described. There 

 were a number of steam vents, with the same variety of delicate linings 

 and shades of coloring. In Fig. 36. 



some of the springs iron pre- 

 dominates over the sulphur, ' //^ ^ ^ 

 and to these we gave the name , vU''//. 

 of Iron Springs. In others 4 MM^S^^im.^ 

 the sulphur is in excess, and 

 those we called Sulphur 

 Springs. We passed springs 

 of various kinds and temper- __ 

 ature every few yards, on either ^^^ 

 side of the creek 5 some depos- "^^'^ 

 ited great quantities of iron, 

 others sulphur, but most of 

 them large quantities of both. 



The grades of coloring are as varied, though not as vivid. The basins of 

 the springs are of a great variety of shapes; the tendency, howe^'er, is 

 to a circular form. The basin of one spring is funnel-shape.d, circular, 5 

 feet in diameter, the water as clear as crystal, and 30 feet in depth. 2. 



