Ely Springs Dolomite

The Ely Springs Dolomite is an Ordovician period geologic formation in the Southwestern United States.
The Dolomite formation is exposed in areas of the northern Mojave Desert in Inyo County, California, southern Nevada including the Ely Springs Range, and southwestern Utah.
Fossils.
It preserves fossils dating back to the Ordovician period of the Paleozoic Era.