Geology Cahaba River Walk

Coal Seam at Landing
- Photo Credit: Francesca Gross
find the fossils
- Photo Credit: Francesca Gross
Fossils along the river
- Photo Credit: Francesca Gross

The topography of the Cahaba River Walk consists of small rolling hills typical of the Birmingham area.  The Alabama Ridge and Valley created these curls of land when the African Plate collided with the North American Plate in the Paleozoic era. Just across the street from the Cahaba River Walk parking area is an exposed cross section of sandstone with a thin and brittle stratum of visible coal.

The watershed geologic unit is Pottsville Formation (Ppv) with with river alluvium (Qal) under the bed of the river. Just to the southeast of the Grants Mill Bridge, a major fault known as the Hogpen Branch Fault lifts the river bed causing areas of rapids upstream. Part of the Appalachican thrust belt, the fault dips to the southeast. The fault roughly parallels the southeast fault of the Cahaba Coal Field.