A dip into the deep past

Another dip into my Cabinet of Curiosities, a.k.a an old shoe box. These are fossils from the beach at Whitby in Yorkshire. 
The one on the left shows a number of belemnites and the one on the right is a single ammonite.
Belemnites belong an extinct order of marine squid-like cephalopods that existed from the Late Triassic to Late Cretaceous, 200 to 65 million years ago. Unlike true squid, belemnites had an internal bullet-shaped skeleton.
Ammonites are a group of extinct marine molluscan animals with a spiral shell. They lived in the Devonian and Cretaceous from 409–66 million years ago. The name ammonite has an interesting history. Pliny the Elder (who died in 79 AD near Pompeii) called these fossils ammonis cornua ("horns of Ammon") because the Egyptian god Ammon was typically depicted wearing ram's horns.