The course of the Teays River, a large Tertiary stream, including the present Kanawha and New Rivers and their tributaries, has been traced from its source in the Piedmont region, westward to the Illinois River. This stream, more than 800 miles long, crossed the entire Appalachian region, passing through the abandoned valley, from a point near St. Albans to Huntington, West Virginia. From Chillicothe, Ohio, the buried valley of the Teays has been traced, by means of well records, in a westerly direction across Ohio, Indiana and Illinois to the_ Mississippi. The Teays River was a mature stream and drained a maturely dissected region. An early glacier, Kansan or pre-Kansan, dammed its westerly course in Ohio, ponding the waters, forming lake-like expanses in southeastern Ohio. In the ponded areas, slack-water deposits were laid down. The broad valley of the Teays (Kanawha-New) River was an avenue for the migration of plant life from the Piedmont region to southeastern Ohio.