PRELIMINARY LOOK AT TRACE FOSSILS IN THE LATE CRETACEOUS COLERAINE FORMATION; HILL ANNEX STATE PARK, CALUMET, MINNESOTA

There has been little mention of trace fossils of the Coleraine Formation in the literature discussing the Cretaceous outcrops in Minnesota. The paleontological work to date has focused primarily on the marine invertebrate and ichthyological assemblages that have been recovered. The Coleraine formation is made up of conglomerates, shales, and sandstones that are considered Cenomanian to Turonian in age. The paleo environment for the Coleraine Formation is characterized as a sequence of transgressions and regressions of the Western Interior Sea. The trace fossils found at Hill Annex State Park consists of burrows of Ophiomorpha and possibly Thalassinoides, along with others showing evidence of crustaceans that have not been described. Borings in the fossilized wood show evidence of Teredolites sp. and a wood boring Gastropod of unknown type.