The Soda Butte and other small wonders
Somewhere on the NE Entrance Road stands out a small conical hillock with the funny name 'Soda Butte'. There used to be a hotspring here, now only producing some hot water and 'rotten eggs gas' (H2
S), that build this mound of travertine. More than a century ago, it bubbled and steamed and grew into this butte. Then the steam and sulfur found another way out of the earth...
Mammoth Hotspring Terraces
At the entry of Mammoth village, there is a white mountain. It is so white (with also some brownish parts) that you wonder what material it is made of. Well, it's travertine, a kind of limestone, made from the calcium and bicarbonate that come to the surface with the hot water from the spring. The Terraces were first described by the Hayden Survey in 1871 as White Mountain Hotspring.
Fresh travestine is white, but algae and cyanobacteria may give it bright colours.
There is also a strange hillock, Liberty Cap
(a reference to the cap worn by partisans of independence during the American Revolution). The cone was made by a hotspring that put layer on layer of travertine, much like a stalagmite in a limestone grotto. The hotspring found another outlet, so the spring is now inactive.