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 colloquially known as “Big Eye”. 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, as well as the characteristic scale pattern.