These images show an interesting fossil combination. The fossil ensemble was found in the Kope Formation (Latonia (Eden) Shale) of Carroll County, Kentucky, USA. The main fossil appears to be a Prasapora simulatrix (Ulrich, 1886) bryozoan. The colony grew on top of the shell of a Hormotoma gracilis (Hall, 1847) gastropod. The imprint of the shell's spiral looks intact. These fossils existed in the Ordovician Period. I have found that when in an area with Kope Formation fossils that bryozoans tend to cover other fossils and preserve details on the fossils they cover. See the cephalopod fossil in this 2010 posting.
See more examples of Prasapora simulatrix bryozoan fossils:
http://www.drydredgers.org/thumb_by_bryozoan.htm#Prasapora
The Latonia Formation consists of three members: McMicken, Southgate, and Economy.
