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 fish is a palaeoniscoid of uncertain affinities. The detail for a specimen nearly a third of a BILLION years old is remarkable. Note particularly the detail to the skull, vertebral column, and tail. It is found here in association with an ammonite of the genus Anthracoceras. Typically these two members of the fauna are not found together, making this a most unusual piece. The most unusual feature is that the jaws are preserved within the shell of this fine example.