| Two Great Basin explorers examine an exposure of fossiliferous limestone in the vicinity of Little Antelope Summit, White Pine County, Nevada, that produces beaucoup fresh water coiled gastropods from a middle Eocene geologic rock unit that is correlated statigraphically with an Eocene sedimentary section of the upper Cretaceous to middle Eocene Sheep Pass Formation, White Pine County, Nevada. The Sheep Pass deposit yields abundant fresh water gastropods, pelecypods (AKA, the bivalves), and ostrocods (a minute bivalved crustacean--sometimes colloquially called a seed shrimp)--in addition to roughly 40 species of vertebrate remains: amphibians (spectacular complete frog skeletons, in particular), reptiles, birds, and early extinct mammals--the first confirmed Eocene vertebrate fossil-bearing geologic rock unit recognized from the Great Basin district. |