Geologic Map of New Jersey

The traprock deposits of New Jersey are of late Triassic, early Jurassic age.
During Mesozoic times the region was dominated by Lake Lockatong, a huge body of water covering much of the region. Volcanic activity produced igneous deposits of several different types. These included intrusive sills of diabase and extrusive flows of basalt.
Igneous features of the area include the Watchung Mtns., the Palisades and the Bergen Hill/Snake Hill rock in Secaucus

Click on the Map For Details on the Traprock Formations