Geologic map of northern NJ. The Newark rift basin is highlighted in blue. Rock units in the Newark basin inclide Triassic- and Jurassic-age siltstone, shale, and sandstone and conglomerate; Jurassic basalt (lava flows); and Jurassic diabase (intrusive igneous rock). NB is New Brunswick, NJ. Modified from NJ Geological Survey (1994).