6" Cretaceous Ammonite (Simbirskites) Cluster - Russia
This is a very aesthetic cluster of Simbirskites ammonites from the Volga River in Russia. There are also a few Rhynchonella brachiopods associated with the ammonites. The largest ammonite is 3.4" wide and the entire piece is 6" wide and 4.7" tall It has been very nicely prepared and the base has been cut flat so that it displays aesthetically on a flat surface. These ammonites are Cretaceous in age.
Ammonites were predatory mollusks that resembled a squid with a shell. These cephalopods had eyes, tentacles, and spiral shells. They are more closely related to a living octopus, though the shells resemble that of a nautilus. Ammonites appeared in the fossil record about 240 million years ago and they barely survived several major extinction events. The last lineages disappeared 65 million years ago at the end of the Cretaceous.