278 REPORT UNITED STATES GEOLOGICAL SURVEY. 



DESCRIPTION. 



The Western Group occupies an area of about 200 yards by 300 yards. 

 The first springs met with are about 900 feet from the mouth of the creek, 

 from which they are distant about 500 feet, at the foot of a hill, on the 

 side of which there are mudholes and old steam vents. These springs, 

 Nos. 1 to 7, form a subgroup, which needs no further description than 

 has been given in the catalogue just presented. The drainage from the 

 springs flows directly south to the creek over a gently sloping, area of 

 geyserite, joining the drainage from No. 43, which is further east, and 

 that from the subgrouj) next to be described, which is the one in which 

 No. 8 is the principal spring. This subgroup is on a higher level than 

 the one just described, and a strong stream of warm water proceeds 

 from it, flowing in a brilliantly-colored water-way, which has a vigorous 

 growth of confer voids. The springs worthy of particular mention are 

 the Boiling Caldron, the Great Crater, and the Cream Spring. 



The Boiling Caldron (IsTos. 8 and 9) is composed of two basins sepa- 

 rated by a very narrow strip of yellowish geyserite. No. 8 is the principal 

 spring. It is an almost rectangular basin 10|^ by 17 feet. At the south 

 end of the spring is a black shelf of deposit, and on the west side a small 

 yellow mound, in which the water is boiling vigorously, and from which 

 huge volumes of steam escape. This escape of steam seems to be much 

 greater in the evening, and about 6 p. m. each day we noticed from 

 camp a large column ascending. The water spouts from 3 to 5 feet dur- 

 ing the escape of the steam, which has periods of greater violence fol- 

 lowed by lulls. The water in the pool has a greenish-blue tint, and there 

 are two centers of ebullition. The temperature on the spouter was 201^ 

 F., and in the pool 199° F. at the surface and 202° F. at the bottom. 

 No. 9 is' longer than No. 8, measuring 24 feet, but is only from 11 to 15 

 feet in width. Water connects from one to the other. It has a yellowish- 

 white basin, which appears to be simply a sort of crust over a deep basin. 

 The holes broken through it are black, and number 9 or 10. There are 

 three important ones that are strong spouters, being in action whenever 

 observed ; the temperatures were 200°, 201°, and 201^. The water-way 

 leading from the Caldron is beautiful, lined with white and orange col- 

 ored cakes or plates of silica. The Boiling Caldron belongs to the class 

 of constantly agitated springs, although it has periods of increased ac- 

 tivity alternating with those of less action. 



The Great Crater (No. 17) occupies a crater-like depression, 6 to 8 

 feet below the general surface. The spring is approximately circular, 

 measuring 40 by 45 feet. In the center is a basin 20 feet deep, in which 

 the water has a deep-greenish tint; bordering the basin is a yellow shelf- 

 like projection; near the outlet is an opening through this shelf, where 

 the temperature is 162° F., while in the main basin it is 105^ F. The 

 central basin steams slightly, and occasionally a few bubbles rise to the 

 surface, but generally the spring is quiet. At one side there is a bub- 

 bler, in which the temperature is 190° F. A strong stream flows out 

 from the spring through a yellow-lined water-way which descends to 

 the creek level. The overflow of No. 18 finds its way into the crater, 

 and whenever there is any overflow from No. 16, it pours into it also. 



Cream Spring (No. 18). — This is a beautiful creamy-white basin with 

 a fine scalloped border 3 or 4 inches in height. The center of the spring 

 has a bluish tint, and there are three or four centers of slight bubbling. 

 The total length of the spring is 28 feet, but one end is a shallow red 

 lined basin, the main spring being 19^ feet by about 13, the shape being 

 ovaL The temperature is 160°, and the spring belongs to the class 

 of quiet springs. 



