This is an area of very rugged, heavily wooded hill country with the greatest landscape relief in the state. It is a typical Appalachian hill country dominated by high hills and deep, steep-walled bedrock valleys. Some hill tops are 1200 -1400 feet above sea level. Much of the exposed bedrock is erosion resistant Mississippian and Pennsylvanian age sandstone including the famous Blackhand Sandstone formations of the Hocking Hills Region. Further east of Hocking, the Pennsylvanian Age bedrock is comprised of repetitive layers of sandstone, shale, coal, and clay with an occasional thin layer of limestone. Because of the ruggedness of the landscape and its ancient, infertile soils, this region is less populated and developed than most of the rest of Ohio thus providing a more wilderness-like setting. Accordingly, there are possibly more plants and animals occurring here than in any other region of the state. Some of the very rarest species of plants found growing here are disjuncts, normally found growing in the Appalachian Mountains far to the south of Ohio. They owe their presence in Ohio to the ancient, preglacial Teays River which had its headwaters in the Blue Ridge Mountains of North Carolina and provided a corridor for their northerly range expansion for 200 million years or so before the beginning of the Ice Age. Other typically Appalachian species of plants found within the Unglaciated Appalachian Plateau are normally found growing in this type of terrain which has never altered by continental glaciation, or are simply growing at the northern edge of their more southern range. Although this region of Ohio was heavily disturbed and denuded by the more than 40 charcoal iron furnaces of the early 1800s and later by surface and deep coal mining, the forests have made a remarkable come back. Today, second growth forest covers more than 70% of the region, more than in any other part of Ohio. The forests here are largely dominated by mixed oak woodlands and mixed mesophytic woodlands along with a limited number of Yellow Pine, Pitch Pine, and Virginia Pine which favor the dry acidic soils of the ridge tops and south facing slopes.