This brachiopod was found in the Waldron Shale of Clark County Indiana. It is a Silurian Period brachiopod that appears to be an Eospirifer radiatus. I used the Fossils of Ohio book pages 230-231 to get this identification. The book describes it as being from the Niagaran Series which is synonymous with the Waldron Shale. The brachiopod is not fully intact with one side partial broken off revealing solid shale and calcite crystals. Its dimensions are 3.5 cm long and 3.3 cm wide. The radial lines are fine and very tightly spaced. The specimen needs to be cleaned of residual matrix.
WOW! Check out this Estonian Museum specimen database of an Eospirifer: http://sarv.gi.ee/specimen.php?id=56117 Now this is an impressive museum collections database with a sweet interface. They have 100 Kentucky specimens including three holotypes of a stromatoporoid and 98 Indiana specimens As of this writing the database has 142802 entries with 15060 images.
Different views of the same specimen found in Clark County, Indiana.
The bottom image is from page 231 of the Fossils of Ohio (Bulletin 70, Rodney M. Feldmann Editor, State of Ohio, Department of Natural Resources, Division of Geological Survey, Columbus Ohio 1986) figure 10-12 of specimen from Wenlock Limestone, Dudley, West Midlands, England.
Also check out the nice collection of Eospirifers at the Indiana State Museum on-line database.