Paleontology in Delaware

There are no local rocks of Precambrian, Paleozoic, Triassic, or Jurassic age, so Delaware's fossil record does not begin until the Cretaceous period.

[3] One of the most common Cretaceous invertebrate species found in the state is the crab Callianassa mortoni, whose claws are abundant in the Merchantville Formation.

[1] Delaware continued to be largely covered by seawater during the Cenozoic era, although its level rose and fell over time.

On land, the local inhabitants included beavers, a possible saber-toothed cat, chalicotheres, deer-like animals, rabbits, peccaries, hornless rhinoceroses, and small primitive horses.

[6] Folklorist Adrienne Mayor has mused that the depiction of the grandfather of the Monsters in the Delaware myth resembles modern portrayals of Tyrannosaurus rex as a fearless, superlative predator.

Delaware women once collected "uki rocks" which were imprinted with the tracks of small dinosaurs attributed to mythical Little People.

[8] In the summer of 1991, highway workers digging for a construction project near Smyrna made a major Miocene fossil deposit.

Although most of its fossils were of marine life, researchers have regarded its mammal remains as the best discovered north of Florida in the eastern United States.

The site's famous mammals included beavers, a possible saber-toothed cat, chalicotheres, deer-like animals, rabbits, peccaries, hornless rhinoceroses, and small primitive horses.

The deposit may have formed as terrestrial animal carcasses bloated and drifted downstream and out to sea, mingling their remains with those of marine life.