Natural Features & Ecosystems
Pinnacles National Park gets its name from rock spires and crags that are remnants of an ancient volcanic field, which eroded over millions of years as portions of the field moved northward along the San Andreas Fault. Rock debris in the form of boulders has weathered and settled, leaving behind spires of volcanic rock and talus caves.
Did You Know?
National monuments are created by a presidential proclamation, and national parks are set aside by acts of Congress. Other units of the National Park System include recreation areas, seashores, national historic sites, and memorials.