| A seeker of Paleozoic paleontology investigates the prime fossil locality in the Upper Mississippian Chainman Shale, as exposed in the vicinity of Cerro Gordo ghost town near the crest of the Inyo Mountains. Ammonoids, orthocone nautiloid cephalopods, pelecypods, shark teeth, and even fragments of terrestrial plants occur in a 50-foot section of dark gray to black, commonly fissile, slighly metamorphosed shale; bluish-gray rocks at upper left of picture, just below the blue sky, belong to the Lower Mississippian Tin Mountain Limestone. |