Gray Shale Red Sandstone & Red Shale tream Hillside Spring Glacial Erratics Surface of Lava Flow Puddingstone Boulder Carriage Road Erosion at Parking Lot Trailside Basalt Outcrop Trailside

Geological Cross-Section of the Watchungs.

The cross section below shows the rocks of the Watchung Reservation and surrounding area, revealing the relative positions of the lava flows that erupted in this region and the sedimentary rock layers between them.

Illustration by Susan Anderson