This Brevispirifer gregarius (Clapp, 1857) is almost a textbook example of a fossil specimen. Included with this posts are the illustrations from Henry Nettelroth's Fossil Shells of the Silurian and Devonian of Kentucky from 1889. That book referred to this fossil as a Spirifera gregaria (Clapp, 1857). These fossils are used as identification markers for the stratigraphic layers in the Jeffersonville Limestone. Devonian fossil was found in Jefferson County, Kentucky, USA.
