Raritan Formation

Raritan Formation (Cook, 1868) - Consists of upper clayey-silt (Woodbridge Clay Member) and lower sand (Farrington Sand Member) in map area. Woodbridge Clay Member is palered-orange weathering, grayish-black to dark-gray micaceous silt, very clayey; interbedded and locally interbedded with light-gray, very clayey, fine- to very-fine-grained micaceous sand containing primarily quartz and feldspar. Abundant layers of small, pyrite-coated wood fragments. Siderite in discontinuous beds and in flattened slab concretions as much as 1 m (3 ft) in diameter are common. Mollusk casts common in siderite near top of formation. Typically about 24 m (80 ft) thick. Farrington Sand Member is white, fine-to medium-grained, very micaceous, crossbedded sand, interbedded with thin to thick, darkgray, silty beds. Exposed only in pits dug below the overlying Woodbridge Clay Member. Typically about 8 m (25 ft) thick. Fossils include late Cenomanian ammonites Metoicoceras bergquisti and Metengonoceras sp. in upper part of Woodbridge (Cobban and Kennedy, 1990) and pollen of the Complexipollis-Atlantopollis assemblage zone (= Zone IV) of late Cenomanian to early Turonian age (Christopher, 1979; 1982).