Lockatong Formation from the Newark rift basin.Top: Outcrop of cyclical Lockatong Formation from the Eureka Quarry near Eureka, PA, Pennsylvania. Photo by P.E. Olsen. Bottom: Part of the Nursery Core near Princeton, NJ, recovered the gray and black Lockatong Formation. The blackest part of the core are sediments that accumulated at the bottom of a deep, anoxic lake. Each 3-ft-long core box holds 9 feet of core. Photo by R.W. Schlische.