1) Cretaceous ammonite
Found on
https://www.crosswordclues.com/clue/polyptychites
Polyptichites is the perisphictacean ammonite genus from the Lower Cretaceous of Russia. The shell is subinvolute and coarsely ribbed; ribs bifurcate or trifurcate mid or low on the flanks and cross over the rounded venter. The umbilicus is relatively small and deep. Outer whorls partially envelop the previous leaving a fairly deeply impressed dor...
Found on
http://en.wikipedia.org/wiki/Polyptychites
No exact match found.
