Ammonites

From the press release:
7th Annual Palace Gem & Mineral Show

New Mexico History Museum

Among the samples you're likely to see at the Palace Gem & Mineral Show are ammonites, fossils of extinct marine animals that thrived in the Paleozoic and Mesozoic Eras, some 400 to 65 million years ago. Ammonites were cephalopods, related to squid, octopus, cuttlefish, and the chambered nautilus. Photo by Natalie Baca, New Mexico History Museum.

Note: Representative image at left is often cropped for display purposes. Downloaded high-resolution images are not cropped.