Thursday, July 19, 2012
Similar fossils like are shown in Plate III Figures 17-19 (page 45) in Cincinnati Fossils An Elementary Guide to the Ordovician Rocks and Fossils of the Cincinnati, Ohio, Region edited by R.A. Davis 1998. The guide describes the fossils as "characteristic flat, blade shape, and the pattern of diamond-shape apertures." The text goes on to say they are found in the Mt. Hope and Fairmount subdivisions (Cincinnatian Series, Maysvillian Stage).
Thanks to Herb for the fossil and identification help.
Next image is of the fossil wet which highlights predation on its surface.