Pen Formation

The Pen Formation is a Campanian-age geologic unit in the western United States.

Sharks are well known from the Pen Formation.

[1] Other fishes include Xiphactinus,[1] the ray Ptychotrygon,[1] and gar.

[1] The nodosaurid ankylosaurs Acantholipan and CPC 273 have also been found in the Pen Formation.

[2]