In the unglaciated area of southern Ohio, tributaries reflect the adjacent hills, which are considerably reduced: low gradients, broad valleys for the size of the modern streams, and dendritic patterns, all features of maturity. The largest of the tributaries in Ohio are the Marietta River, Hamden Creek, Albany River, Barlow Creek, Portsmouth River, Logan River, Bremen Creek, Putnam Creek, Cambridge River, Groveport River, Mechanicsburg Creek, and Wapakoneta Creek.[1] The Cincinnati River flows northeastward from the southwest corner of Ohio to Dayton, to join the Teays River.[3] That a divide existed between the preglacial Teays and the Miami watershed.