Description: The Bear Gulch Limestone is a deposit of some 70 square km in extent and 30 m in depth that has been a source of one of the most diverse assemblages of fossil fish with some 110 species having been described over the past 30 years. Most were new to science, and provided a unique view of the marine environment of Mississippian times. Fine preservation of both fish and invertebrates is a hallmark of these deposits, presumably due to an anoxic depositional environment. This is a good example of a Paleoniscoid fish known as Phanerosteon. The paleoniscoids were the first ray-finned fish, a feature readily seen here. Some 40 or more families appeared during the Carboniferous and Permian Periods. This superb example shows the teeth and fin rays to good advantage on this fine part/counterpart example. The genus went extinct during the early Permian.