Stunning, 3.5" Dactylioceras Ammonite Cluster - England
This is a cluster of Dactylioceras (Orthodactylites) tenuicostatum ammonites from the Grey Shales of North Yorkshire, England. The ammonites are Lower Jurassic (180 Million Years Old) in age and preserved in a cluster. There are 6 complete ammonites in this cluster and the rock has been prepped in an artistic fashion that allows for aesthetic presentation of the ammonites. The rock matrix has been cut flat so the specimen sits nicely on a flat surface.
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.