Fig. 234. Terrace and Cones of Siliceous Sinter deposited by Geysers, Yellowstone National Park
Carbonated springs. After all the other signs of life have gone, the ancient volcano may emit carbon dioxide as its dying breath. The springs of the region may long be charged with carbon dioxide, or carbonated, and where they rise through limestone may be expected to deposit large quantities of travertine. We should remember, however, that many carbonated springs, and many hot springs, are wholly independent of volcanoes.
Fig. 235. Mount Shasta, California
Fig. 236. Mount Hood, Oregon