Here are two pictures of a pyritized Strophodonta brachiopod fossil. It was found in the Silica Formation of Sylvania, Ohio USA. The creature lived in the Middle Devonian Period. Learn more about where these fossils are found at Olander Fossil Park web site.
Thanks to Vic for the pictures of this fossil.
My friend Dave has a blog with a special section for the fossil from this area. Click this to go to Views of the Mahantango blog.