|Description: The giant ground sloth, Megalonyx, is represented at Big Brook by its claw bones. There have been only a few of these claws recovered. They are flattened and curved, gradually forming a blunt point. The claw cores are always missing the claw sheaths, made of chitin. They are 19 cm (about 7.5 in) long and about 10 cm (about 4 in) wide.
There have been other parts of the skeleton, such as vertebra, have been found in other parts of the state. So far, there has been no other identifiable material found at Big Brook or at least recognized.
Commonality: Any material from the ground sloth is rare.
Similar fossils: There are no similar fossils.
Size: Judging from the size of the claw core and comparing with complete skeletons found in other southern states, the giant ground sloth was about the size of a modem horse, about 2.5 meters (about 7.5 feet) in length.
Notes: The presence of the giant ground sloth is inconsistent with the usual Ice Age fauna and probably existed during the interglacial periods when the temperature was much like it is today. Even during the warm periods, New Jersey represented the northeastern range of Megalonyx. A claw that was found at Big Brook is presently on display in the New Jersey State museum in Trenton.