Pen Formation
The Pen Formation is a Campanian geologic unit in the western United States.
Sharks are well known from the Pen Formation.
Other fishes include Xiphactinus, the ray Ptychotrygon, and
gar.
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Wikipedia
The Pen Formation is a Campanian geologic unit in the western United States.
Sharks are well known from the Pen Formation.
Other fishes include Xiphactinus, the ray Ptychotrygon, and
gar.