The Discovery

In 1964, two students conducting a hydrological survey stumbled upon a trail of large fossil footprints 50 metres (165 feet) offshore from Horton Bluff, Nova Scotia. They were exposed at extreme low tide when a storm had swept away the overlying mud. The discoverer, Dr. David Mossman, is now a professor of Geoscience at Mount Allison University in Sackville, New Brunswick.

Dr. Mossman eventually mapped 27 footprints spanning a distance of 20 metres (65 feet). Their preservation in Lower Carboniferous Period rock made them, at the time, the oldest vertebrate tracks in the fossil record. They remain the oldest vertebrate fossil trackways ever found in Canada.

Learn more about the science of trackways.

A Mysterious Trackway

Not only was the trackway old, it was of unprecedented size. Each footprint was 30 cm (1 foot) long and they were spaced 30 cm (1 foot) apart. The tracks are deep with raised edges, suggesting that the animal was heavy and the mud very soft when it waddled by approximately 350 million years ago. The absence of claws and the width of the trackway show it as having been made by an amphibian.

It is impossible to identify the animal, as no bones of an amphibian large enough to have made these tracks have ever been found in Canada. We can only guess its identity.

One candidate is the semiaquatic predator Eryops. This bulky amphibian grew to be over 2 metres (6 feet) in length. Its size and powerful jaws made it a formidable predator in water. On land, however, it lumbered along on short legs and was itself vulnerable to predation.

It is also possible that the animal that made these large tracks was a type of extinct amphibian more related to crocodiles than to living frogs or salamanders. If so, it probably had fangs and would have been a most feared carnivore in the Carboniferous swamp.

Preserving the Fossil Record

Late in the summer of 1979, a team from the Nova Scotia Museum cast this spectacular trackway in fibreglass to provide a permanent record. By 1991, roughly half the tracks had vanished as the beach rock fell prey to the eroding action of the tides.