From Ohio History Central
Conkle's Hollow is part of the Hocking Hills State Park near Logan, Ohio. It is one of Ohio's most popular natural history attractions.
Conkle's Hollow is a gorge. Water slowly eroded away Blackhand Sandstone, creating the ravine. Sandstone is a very porous substance and much more susceptible to erosion than many other types of rocks. Cliffs, standing approximately two hundred feet in height, surround three sides of Conkle's Hollow. Near the end of the ravine, the cliffs are only three hundred feet apart. Plant life, including hemlock and birch trees and various types of wildflowers, thrive in the gorge.