Fly Ranch Geyser, Washoe County. This is not a natural geyser but a leaking geothermal well that was drilled in 1964. The hot-spring deposits consist of siliceous sinter and travertine, and the red and green colors are caused by thermophilic algae. (Information from Road Log for Field Trip to San Emidio Desert, Gerlach, Fly Ranch Geyser and Orient Farms, by Dennis T. Trexler and Michael B. Stewart, High Rock Holding LLC.)