Knowledge Bank

Stratigraphically significant compression floras have been found in lower Conemaugh ironstone beds and lower Conemaugh dark argillaceous shales in the 7-11 Mine, Columbiana County, Ohio. The known fauna associated with the ironstone beds is limited to branchiopods, myriapods, and a single arachnid. The dark argillaceous shales yielded both invertebrate and vertebrate fossils including freshwater sharks, fish, ostracods, branchiopods, myriapods, arachnids, and insects. The absence of any marine fauna supports the contention that both the ironstone beds and the dark argillaceous shales were deposited in a freshwater environment.