3.9" Polished, Agatized Ammonite - Madagascar

Polished, Agatized Ammonite - Madagascar #59915

This is a beautiful, 3.9" wide, polished ammonite fossil from the Mahajanga Province of Madagascar. It's Early Cretaceous (Albian Stage) in age, or approximately 110 million years old and of the genus Cleoniceras. The fossil itself was replaced by agate and has been polished to reveal the beautiful, "oak leaf" shaped suture pattern of the animal.

Ammonites were predatory mollusks that resembled squids with shells. These cephalopods had eyes, tentacles, and spiral shells. Though their shells resemble that of a nautilus, they are actually more closely related to living octopuses. Ammonites appeared in the fossil record about 240 million years ago, barely surviving several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.

Artist's reconstruction of an ammonite, by Nobu Tamura

More about ammonites