NO. 3 SMITHSONIAN EXPLORATIONS, IQI5 9 
Fic. 12.—Small geyser and hot spring on bank of Firehole River, showing 
geyser and hot-spring deposit side by side. Small vents on side of spring erupt 
quite frequently. Photograph by Walcott. 
Fic. 13.—Sulphur Mountain Geyser boiling, prior to small eruption. Coloring 
in mouth and throat of geyser varies from rich cream above to deep red and 
buff below. Minor details of siliceous deposit about area flooded by hot sili- 
ceous water are most beautiful. Photograph by Walcott. 
