[1] The water from the aquifer is generally fresh, acidic, corrosive, and low in dissolved solids.
It is believed that the mercury detected in certain wells in the aquifer is due to human activity, and is not thought to occur naturally.
[1][4] The aquifer covers about 3,000 sq mi (7,800 km2) of the New Jersey coastal plain, reaching as far north as Monmouth County, and extending to the south along the Atlantic coastline, and west to the Delaware Bay.
[1] During the Middle Miocene epoch – about 11.6–16 million years ago – the Atlantic Ocean covered what is now New Jersey from the Raritan Bay to the Delaware River.
During this time, the ocean retreated and advanced, which deposited a 780 ft (240 m) layer of minerals that became known as the Kirkwood Formation.
Much of the feature is below sea level, and few sections are observed near the surface, primarily in pits and along roadcuts.
It consists largely of sand, with localized areas of gravel and clay, making it prone to erosion.