Catalog Number: CG-0091

Update: Royal Mapes has helped me identify this as Schistoceras. After sketching the suture pattern, this was the best genus in my opinion, but I did not know based on the shell ornamentation and the size. Mapes confirmed my suspicion based on suture pattern, conch width and ornamentation.

I have had this specimen since last year. Upon closer inspection, I learned that this is in fact an Ammonoid. The unique suture pattern on the exposed portion of the shell is a dead match for identification. Early on, I had the genus narrowed to a few candidates. I considered Wellerites or Schistoceras. I ruled out Wellerites as the suture pattern, however it’s really close.

I am aiming to prep the specimen much better. I want to try and show a more clear suture pattern to showcase the beauty of this genus. The shell itself is very flat, very thin compared to something like metacoceras.

Suture Pattern

This is my drawn suture pattern while examining under a microscope.

Schistoceras suture

Schistoceras Specimen Photos

This has been a hard specimen to photograph. The eroded suture structure and fossilized shell erosion has given it a lot of complex shapes. I am still in the process of prepping it, so hopefully better photos can follow.

Comparison with specimen KUMIP 262484

Below is a specimen of Schistoceras missouriense from the Drum Limestone of Montgomery County, Kansas. It is identified as KUMIP 262484 at the University of Kansas Natural History Museum.The shape is somewhat similar to my specimen, however the real 1:1 match is the shell pattern. The wavy black shell is exactly what I see on my specimen CG-0091.

KUMIP 262484 from the Pennsylvanian Atlas of Ancient Life


  • Mapes, R.H. et al, 1997, Pennsylvanian Cephalopods of Ohio, Part 2 Ammonoid Cephalopods, P. 214-215, P. 242-243
  • McKinzie, M, McLeod, J., 2003, Pennsylvanian Fossils of North Texas, P. 42
  • Moore, R.C. et al, 1957, Treatise on Invertebrate Paleontology, Cephalopoda Ammonoidea, Part L, Mollusca 4, P. L63-65.
  • Shimer, H.W, Shrock, R.R., 1944, Index Fossils of North America, P. 566 & P. 573

More online for Schistoceras