Massachusetts: dinosaur tracks (state fossil)

Whereas dinosaur bones are lacking in the state of Massachusetts, tracks are common. Several types of dinosaur prints are known from the state, including Eubrontes, Grallator, Anchisauripus, and Otozoum. Rather than pick a single one of these, the legislature designated the generic "dinosaur track" to cover them all.

These tracks are found in Jurassic Period sediments from about 200 million years ago. At that time, the supercontinent of Pangea was rifting apart and the Atlantic Ocean was beginning to form. Mudflats along the western shore of this new seaway provided the perfect environment for the preservation of the footprints of dinosaurs that passed along the beaches.

Trace fossils such as tracks are given different scientific names from the animals that made them, because it is difficult or impossible to be sure which animal made which track. However, structure of the foot and shape of the footprint can allow some educated guesses. Some scientists have suggested that Eubrontes is the footprint of Dilophosaurus, and Grallator is the track of a small theropod dinosaur like Coelophysis or Podokesaurus. These tracks exhibit three toes, like those of birds, and were originally thought to have been bird tracks. Since today it is recognized that birds are the descendants of small meat-eating dinosaurs, this was not far off.

The first dinosaur tracks in Massachusetts were discovered in 1802, and more have been discovered during the subsequent two centuries. The Dinosaur Footprint Reservation at Mt. Tom near Holyoke preserves a particularly good trackway record.

The state legislature declared "dinosaur tracks" the Massachusetts state fossil in 1980.

For further information:

Massachusetts symbols

Triassic-Jurassic Footprint Project

Connecticut River Geology