Polygonal Rock Face

Erosion has caused polygonal rock faces to form in the sandstone and shale along the southern slope of Chandler Mountain at Horse Pens 40 in St. Clair County.

Erosion-caused polygonal rock faces in the sandstone and shale along the southern slope of Chandler Mountain at Horse Pens 40 in St. Clair County.
Photograph by Mike Neilson
Erosion-caused polygonal rock faces in the sandstone and shale along the southern slope of Chandler Mountain at Horse Pens 40 in St. Clair County.