Fine Mississippian Bear Gulch Fossil Phyllocarid Dithyrocaris

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 fine example of the phyllocarid Dithyrocaris rolfei. The species is also known from the younger Mazon Creek Fauna of Illinois where it is a rare component.