Discovering Dinosaur Footprints

The Connecticut River Valley forms the border between Vermont and New Hampshire and then bisects Massachusetts and Connecticut, eventually emptying into Long Island Sound. During the earliest time of dinosaurs (Late Triassic/Early Jurassic), the land was still part of the supercontinent Pangaea. Fossil evidence shows a tropical environment located much nearer to the Equator than today, with shallow pools and lakes, sandy beaches, and tropical plants. The valley was created as a result of stretching pressures as Pangaea began to pull apart and what became Africa moved southeast, what became North America moved northwest, and what became the Atlantic Ocean filled in between them. At various times, the region has been tropical, mountainous, volcanic, and glacial.

For thousands of years, the Native Americans living in what is now western Massachusetts and Connecticut probably noticed what looked like bird footprints in the sandstone layers exposed through erosion by the river. The first record we have of European colonists noticing tracks is Pliny Moody’s discovery of several footprints in sequence when he was plowing his father’s farm in South Hadley, Massachusetts, around 1801. His family used the slab of footprints as a doorstep by the house and regarded them as a novelty. A few years later, it was sold to a local doctor, Dr. Dwight, who called them the prints of Noah’s Raven, alluding to the raven that flew from the ark and never returned; perhaps the tracks had been made as the waters receded during the flood described in Genesis in the Bible. It is not clear whether Dr. Dwight took this literally, as he certainly could have, but it is possible some of his neighbors did.

In 1835, however, a discovery about 30 miles north in Greenfield had a different effect. A day laborer named Dexter Marsh noticed the foot imprints when he was building a new sidewalk. He showed them to his friends and neighbors, including a young physician named James Deane. The slabs were set aside, rather than used as sidewalk, and instead of assuming biblical origins, Marsh and Deane thought the world of science might be interested, particularly that very new science called geology. Dr. Deane wrote to Edward Hitchcock at Amherst College, who was also official state geologist, describing what had been found and positing that the “bird tracks” had been made at a time when the stone was in a “plastic” state. Eventually, Hitchcock traveled the 20 miles to Greenfield and confirmed that the tracks were new to science and that they appeared to have been made by prehistoric birds. (We now call those birds dinosaurs.)

Hitchcock studied these tracks for the rest of his life. He dug up new ones, and people all up and down the valley gave or sold him tracks they found in quarries or on their farms. As far we we can tell, these were the first dinosaur tracks ever to be thoroughly studied by a scientist. (Fossil tracks had been found in Scotland just a little before this, but the research on them had not gone very far.) Hitchcock developed a new subscience in paleontology that he called ichnology, which means “the study of fossil traces.” Hitchcock’s collection can be seen today at the Beneski Museum of Natural History, on the Amherst College campus. A substantial part of the collection was amassed by Dexter Marsh and purchased by Amherst College at Marsh’s far too early death.

Therefore, while the discovery in Greenfield was by no means the first time human eyes had seen dinosaur footprints, it was a “first” in the sense that it was the beginning of a new science — not only in America, but for the scientific tradition that began in Europe and now is used all over the world. It was thus the first scientific discovery of dinosaur tracks.

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