The fossil and rock records of the Chignik preserve both marine and terrestrial environments. The
mollusk fossil record of the Chignik Formation indicates its age as a late
Campanian to early
Maastrichtian deposit. At least two
bivalve species of the genus
Inoceramus (
I. schmidti and
I. balticus), and the
ammonite Canadoceras newberryanum, demonstrate the formation to be of this age. (The actual genus
Trapa includes water chestnuts, and is not a fern.) Dinosaurs are known from the Chignik formation exclusively from fossil trackways, of which 93.6% are from
hadrosaurids, including both juvenile and adult individuals. The remainder belong to
ankylosaurs of uncertain taxonomic placement,
avians (an ichnospecies of
Magnoavipes similar to
M. denaliensis, and
Aquatilavipes swiboldae), and a single large
theropod footprint attributed to a
tyrannosaur similar to
Nanuqsaurus. ==See also==