Lockatong Formation from the Newark rift basin. Top: 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. Bottom: Outcrop of the Lockatong Formation from the Haines and Kibblehouse Quarry near Chalfont, Pennsylvania. Like the core above, the Lockatong Formation in this outcrop is mostly gray and black and accumulated in a lake. Photos by Roy Schlische.