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Geohydrologic maps of the Potomac-Raritan-Magothy aquifer system in the New Jersey Coastal Plain

January 1, 1994

The Potomac Group and the Raritan and Magothy Formations of late Early to early Late Cretaceous age form an aquifer system consisting chiefly of interlayered beds of quartz sand, silt, and clay. The aquifer system is the most heavily pumped in New Jersey and contains fresh water over an area of about 2,500 sq mi. This atlas illustrates some of the geohydrologic information available for the aquifer system and its confining units. The maps show the configuration of the bedrock surface and the altitude of the top of the confining unit above the aquifer system. Also included are maps depicting the altitude of the top of the aquifer system, three time-related potentiometric surface configurations, and three head declines of the aquifer system. The area represented by these maps lies within the Coastal Plain physiographic province (Fenneman, 1938) and is almost entirely within New Jersey. The area is a low lying, gently rolling plain that ranges in altitude from sea level to about 390 ft. (Woodard-USGS)