286 REPORT UNITED STATES GEOLOGICAL SURVEY. 



appreciated by referencia to the illustration engraved from a photo- 

 graph. There is no raised crater, but a hole bordered by dark-brown 

 spongy -looking masses of siliceous sinter, or geyserite. They are irregu- 

 larly globular in shape, and the onter edge is bordered with flaky masses 

 like many of the springs. The orifice of the spring is 4^ by 5 feet, and 

 2^ feet deep. In this the water appears very dark, although really clear. 

 If, has a temperature of 181° F. at the surface and 190° at the depth 

 of a foot and a half, an<l rises and falls at intervals not determined. It 

 is a boiling spring, being in active ebullition whenever seen by us. The 

 illustration shows it when the water has receded. Back of the crater is 

 a yellow pool, ct of ]^o. 7 in the table given above. The sinings present 

 no evidence of any connection between them. 



No. v5. Yelloic Sponge. — This spring was named from the irregular 

 yellow masses which line the inside of the basin. It is evidently not a 

 true geyser, although the water spurts to the height of several feet 

 above the top of the crater, or mound, in which it is. The latter is 

 beautifully beaded, rising a few inches above the general level. The 

 water rises and falls in the basin and is in constant agitation, splashing 

 and spouting irregularly. The temperature in this basin was 196 when 

 the water was low and 199 when it was spouting. The temperature, 

 189, given under No. 8 in the table, was taken in the opening immediately 

 back of the Yellow Sponge, which is on the same mound. There are 

 several openings which are smaller. 



No. 11. Velvet Spring (Plate XXXV). — This is a very handsome rect- 

 angular spring with rounded edgesand a crenulated border, or rim, 6 

 inches high. The total length of the sjiriug is 19 feet and the width 

 about 11 feet. The spring has two portions. That in the front portion 

 of the basin is a cavern-like hole 6 J by 11 feet, and 8 feet deep. The 

 water in this appears of a beautiful light-blue tint and has a tempera- 

 ture of 198° F. both at the surface and 6 feet below. Back of this and 

 occui)ying the remainder of the basin is a white, velvety platform, over 

 which the water is only a few inches deep. Scattered over this plat- 

 form are small, yellow, mushroom-like masses of geyserite which reach 

 just above the surface of the water. In front of the spring are a num- 

 ber of small, shallow basins, and back is a terraced w^aterway which 

 carries water from springs 2 and 3 to this one. When the temperatures 

 given in the table were taken the spring was quiet, but it has periods 

 of active boiling and spouting, although not a true geyser. 



No. ] 3. Bead Geyser. — This geyser has a typical basin, which is 16 by 

 20J feet, in the center of which there is an orifice measuring 1^ by 2 feet 

 4 inches. It was seen in eruption three times, throwing the water from 

 10 to 20 feet. The temperature when the water was rising was 188° F. 

 At another time the temperature was 194° F., and when spouting it was 

 196° F. Surrounding the basin are the beaded, cauliflower-like deposits 

 so typical of the true geyser basins, or bowls. Back of the geyser is a 

 circular spring {a of table) 8^ feet diameter ; temperature 193° F. 



No. 15 (small geyser) is a geyser spring throwing water to the height 

 of 2 to 5 feet at intervals of about 1 minute between the end and 

 beginnings of spoutiiigs, which last about 2 minutes each. 



No. 17. Bronze Geyser (Plate XXXVI). — This is a handsome, deep, 

 gold-yellow and reddish-yellow basin, with bronze ornamentation on the 

 outside. There are two openings, one of which [a) is a fluctuating spring 

 of a deep-yellow color in the interior of the basin 5 h is the spouter (shown 

 to the right in the plate), and is more red in color. It spouts 2 or 3 feet 

 when the basin is full. It is constantly agitated, and probably never 

 throws a definite column of water. The spring is remarkable for the 

 bronze color and luster of the surrounding ornamentation. This luster 



