1) Cretaceous ammonite
Found on
https://www.crosswordclues.com/clue/pachydiscus
Pachydiscus is an extinct ammonite genus from the Upper Cretaceous with a world-wide distribution, and type for the desmoceratacean family Pachydiscidae. Its type is P. neubergicus. Altogether some 28 species have been described. The shell of Pachydiscus is compressed and high-whorled, with an oval or flat sided section. Ribs tend to be differenti...
Found on
http://en.wikipedia.org/wiki/Pachydiscus
No exact match found.
