The 90-foot cliff of the gorge of Sharon Creek found in this preserve has been known to professional and amateur paleontologists and geologists for many years as an excellent exposure of Ordovician fossils. More than 450 million years ago, this region of Ohio was covered by a vast inland sea.
The fossilized remains of the marine creatures which inhabited this sea have been revealed by the eroding force of Sharon Creek during the formation of the gorge. The floor of the creek bed still shows the wave or ripple marks formed when the present-day rock was the mud floor of the ancient sea. The forest above the gorge is mainly beech, maple and ash with scattered tulip-poplar, oaks, walnuts, hickories and many shrub species.