Ammonites and Nautiloids - Jack Co., TX

Kingdom: Animalia, Phylum: Mollusca, Class: Cephalopoda, SubClass: Ammonoidea, Order: Goniatitida

Kingdom: Animalia, Phylum: Mollusca, Class: Cephalopoda, SubClass: Nautiloidea, Order: Nautilida

In Jack Co., TX near Jacksboro, we found a large straight cephalopod Pseudorthoceras. In addition, we found several Gonioloboceras, showing their typical suture patterns, and several other ammonoids and nautiloids including Tainoceras, Metacoceras, and the straight Euloxoceras greeni. We also found many Rugobactrites similar to the one shown below. These specimens are from the Pennsylvanian, Graham Formation, Finis Shale member (c. 300mya).  Special thanks to Dr. Royal Mapes, retired professor from Ohio University, and contributor of the Royal Mapes Collection of the American Museum of Natural History, for helping me with the identification on this page.

Click on images to enlarge.  All measurements are in centimeters unless otherwise shown.

Jack County, TX