Lake Ohio
Prof. G. Frederick Wright, Oberlin, O., who has obtained a world-wide reputation, as authority on gla- cial phenomena, says that at one time, when the ice began breaking, it formed a dam at Cincinnati, to the height of about 550 feet. This would cause the water to back up the trough of the Ohio and its tributaries, to the height of the dam. It is estimated that this dam covered an area of 20,000 square miles. During the summer months the dam would break and the floods would sweep down the valley with terrible velocity. It is interesting to note that the northern tributaries of the Ohio have their sources in the glaciated region. This accounts for the presence of glacial pebbles along many of our streams, beyond the ice covered tract. There are evidences of streams that then existed and poured a vast volume of water and deposited "till" on their ancient shores. The channels of these old streams are now known as "gaps." This Lake Ohio extended into Perry county. Prof. Wright's map marks Logan as the northern limit of the lake, on the Hocking river. Judging from this level, the lake reached to Maxville on Little Mondaycreek, to near Shawnee and McCuneville on Big Mondaycreek, and to Corning on Sundaycreek. It must have backed up a considerable distance on Jonathan's Creek, at least to the Perry county line.8