Ice sheets advanced and retreated across northern New Jersey three
times during the Quaternary. During each glacial advance, sea level
fell nearly 100 meters as water was trapped in the large ice sheets.
Mastodons, mammoths, and other large mammals roamed the newly exposed
land, and their skeletons have been recovered from Pleistocene-age
swamps and peat bogs
that formed during the last glaciation. Fishermen have also dredged the
bones of these mammals from the deep continental shelf off the coast of
New Jersey. This map indicates that the primary exposures of Quaternary
rocks are found along the eastern and southeastern coastal regions.
North American Paleogeography: In North America, glaciers swept
down across Canada several times during the Quaternary, extending south
into the U.S. as far as present-day Kansas. As the glaciers moved
south, they picked up sediment, gouging out features like the Great
Lakes and Finger Lakes, and dropped it in different places, forming
features like Long Island, Cape Cod, and many of the hills from
Pennsylvania to South Dakota.