Side A: Draining the Great Black Swamp. The landscape of northwest Ohio was formed by melting ice and the glacial lakes left behind in its wake. Because of the low gradient (3 feet fall per mile) to the northeast, the flat lacustrine plain evolved into a large swamp. A massive swamp forest with huge hardwoods, broken only sporadically with intermittent wet prairies and savannahs, dominated the landscape. Both prehistoric and historic Indians farmed the flood plains of the Maumee River and its tributaries: Auglaize, Tiffin, and Blanchard rivers. (continued on other side) Side B: Same. (Continued on/from other side ) to texts. The geography of the swamp retarded major settlement up to the Civil War. The 1859 Ohio Ditch Law, a harbinger of drainage legislation nationally, created a cooperative system for individuals to petition county government to surface drain the area. Simultaneous to the surface drainage projects, a massive effort was underway timbering the former swamp forest. Virgin timber for the fleets of America and Europe, grade lumber for the farms and the emerging cities of the area, stave wood for the barrel and stave mills, and the left-over slabwood to fuel the hundreds of clay tile mill kilns dotting the counties of the swamp nearly denuded the landscape of these giant trees. The family-owned clay tile mills allowed underdrainage to transform the swamp into Ohio's most contiguously farmed and productive region.