Only fragmentary remains of dinosaurs have been found in Delaware. All of these have come from the Chesapeake and Delaware Canal, mainly from the spoil piles created by the dredging of the Canal. Various nature groups in Delaware lead trips to the Canal for collecting. Most of the fossils found are those of marine invertebrates (primarily bivalves and gastropods with some remains of sponges, ammonites, and belemnites).
These fossils date to the late Cretaceous (97 to 65 million years ago) and come from the marine sediments of the Marshalltown and Merchantville Formations. Of the dinosaur remains, none have been complete enough for genus and species identification. At least two hadrosaurid (duck-bill dinosaurs such as Maiasaura) teeth have been found. Several toe bones of ornithomimosaur (small and agile theropod predators that look something like plucked ostriches with long tails and arms) dinosaurs and a partial hadrosaurid vertebra have been recovered.
In addition to the dinosaur remains, other vertebrate fossils that have been recovered include: teeth of the marine reptiles Mosasaurus, Globidens, and Tylosaurus; part of a jaw and plates (scutes) of the giant crocodile Deinosuchus; a pleisiosaur vertebra; remains of bony fishes; and shell fragments of the turtles Trionyx, Toxochelys, and other forms. One of the most unique remains found in Delaware is that of a neck bone and a wing bone from a pterosaur (a flying reptile).