202 Geoloyical Survey of the Territories in 1872. 
including several geysers of moderate size. One of these showed 
more plainly than common how dependent the eruptions are 
upon the supply of water. In this, which was called the Minute 
writer, but he is not now prepared to cet present his own 
e n 
should be constantly returned, and the eruption be made con- 
tinuous or dependent upon the will of the exhibitor. 
Shoshone Lake is surrounded by the remnants of an old 
gravel terrace, reaching 112 feet or more above its present level. 
About the mouth of the Geyser Creek, the sand and gravel 
materials of this terrace are more or less firmly cemented into 
conglomerate, porous sandstones and perfect quartzite, by de- 
posits from the hot springs evidently made while the lake 
covered the terrace, the pressure of its waters probably being 
/ j + so 
erosion by the springs has gone on quite extensively, an 
still progressing. Perforated bits of the terrace rocks and of 
the surrounding voleanic sandstone, like those before men 
as occurring in the Firehole Basins, are abundant in the 
crater-like hollows north of the principal springs, which we 
show many sulphur-vents. 
