The rock layers of the 60-foot-tall Brandywine Falls can be read like a book. Each chapter covers millions of years, as ancient seas left behind sediments that were compressed by added layers. The rocks here at the base of the falls were formed more than 400 million years ago.
Brandywine Creek and the"bridalveil" cascades began about ten thousand years ago after the last glacial retreat. The falls have now exposed the harder, yellow-brown Berea Sandstone looming over the softer, deep red Bedford Shale. Since sandstone is more resistant to erosion, the shale below is frequently undercut. As these layers wear away, the story of the earth continues to be revealed.
An exhibit near the falls includes a photo of the waterfalls, a map of the area, and a cross-sectional drawing of the rock with Berea Sandstone (320 million years), Bedford Shale (350 million years), and Cleveland Shale (350 - 400 million years) labeled.