3.1" Cretaceous Ammonite (Mortoniceras) in Situ - Texas

Cretaceous Ammonite (Mortoniceras) in Situ - Texas #198224

This is a 3.1" wide ammonite (Mortoniceras) from the Cretaceous, Fort Worth Formation in Texas. The ridges on the shell are well preserved and the suture lines look very nice. The fossil was partially exposed from the rock it was found in and makes for an excellent stand.

Ammonites were predatory cephalopod mollusks that resembled squids with spiral shells. They are more closely related to living octopuses, though their shells resemble that of nautilus species. True ammonites appeared in the fossil record about 240 million years ago during the Triassic Period. The last lineages disappeared 65 million years ago at the end of the Cretaceous.

What an ammonite would have looked like while alive.