Cornulitid attached to a strophomenid brachiopod valve (Upper Ordovician, southeastern Indiana).
Photograph taken by Mark A. Wilson (Department of Geology, The College of Wooster). <a rel="nofollow" class="external autonumber" href="http://www3.wooster.edu/geology/MWilson.html">[1]</a>
<span class="int-own-work" lang="en">Own work</span>