Brachiopod fossil found yesterday in the Waldron Shale in Clark County, Indiana. It appears to be some sort of
Atrypa brachiopod. This post originally labeled it a
Homoeospira evax (Hall) using the Indiana State Museum as an identification. Note the Waldron Shale was formerly the Niagara Group. This creature existed in the Silurian Period.
Here is a link to the Indiana State Museum collections showing a Silurian brachiopod.
http://museumcollections.in.gov/detail.php?record=0&v=2&s=Indiana%2C+Shelby+County%2C+Waldron&type=browse&t=objects&f=place_made&d=