F. V. Hayden—Hot Springs and Geysers. 105 
Art. XVII.—The Hot Springs and Geysers of the Yellowstone 
and Firehole Rivers; by F. V. HayDEN. With maps. 
(Published by permission of the Secretary of the Iuterior.) 
WE shall not attempt in this article to do more than to give 
a brief description of the hot springs and geysers of this 
wonderland. Their origin does not differ from that of similar 
springs which have been so often described in Iceland, New 
ealand, and on a small scale in other portions of the world. 
ut it was not until comparatively recent date that it was 
known that such a wonderful region existed in our own coun- 
e party under the command of Col. Wm. F. Reyno s, U. 
Engineers, in 1859 and ’60, endeavored to enter the Basin by 
Before entering upon a description of the hot springs. it 
may be well to present a brief summary of the principal geo- 
logical features of the Yellowstone Basin. We may remark 
at once that nine-tenths of the area is covered with volcanic 
material in some form. The basis rocks are the usual metamor- 
i rt 
It is doubtful whether any unchanged rocks older than the Car- 
niferous occur there. The Triassic is probably wanting. The 
Sedimentary rocks occur in patches, covering very r te 
areas, yet presenting evidence that, up to the period of the Eocene 
have existed during the Pliocene period. Below the first cafion 
near the mouth of Shields river, there is one of these basins ten 
