Marshalltown Formation

The Marshalltown seqeunce is comprised of three formations: the Marshalltwon, Wenonah and Mount Laurel. The Marshalltown Formation, at the base, is a burrowed, clayey glauconite sand deposited during a marine transgression. The Wenonah is a slightly glauconitic, micaceous, shelly, woody, clayey silty sand to sandy clayey prodelta silt. The Mount Laurel Formation generally coarsens upsection from glauconitic silty fine sand to a slightly clayey, glauconitic fine to medium quartz sand, with common ovoid phosphate grains near the top of the formation. The Wenonah and Mount Laurel together make up the highstand deposit. The contacts between the Marshalltown and Wenonah and between the Wenonah and the Mount Laurel are gradational.