Page:Popular Science Monthly Volume 45.djvu/206

192 shallowness of the present rocky gorge of the Ohio between Cincinnati and the mouth of the Great Miami. The relative narrowness also of the latter opening between the rocky escarpments is readily visible to the transient traveler. Mill Creek Valley being about twice as wide as that of the Ohio for fifteen or twenty miles below the mouth of the creek; while a low passage joins Mill Creek at Ludlow Grove which sweeps around north of Walnut Hills, and enters the Ohio through the valley of the Little Miami—Walnut Hills, Mount Auburn, and Mount Lookout, the principal residence portions of the city, being upon a high, rocky pedestal completely surrounded by a depression which has at some time been produced by river erosion.

This valley from Cincinnati to Hamilton is now filled with gravel and clay to a great depth. Upon inquiring for the extent to which the old channel had been filled, it was found by the wells which had been sunk in it that the rock bottom descends from Cincinnati to Hamilton, and is considerably lower than the rock bottom of the present Ohio below Mill Creek. Near Ludlow Grove the bed rock is at least sixty feet below present low water in the Ohio. A few miles farther north, at Ivorydale, on Mill Creek, the bed rock where reached was found to be thirty-four feet below low-water mark in the Ohio, while there was nothing to show that in other portions of the valley the gravel was not still deeper. At Hamilton the bed rock was found to be at least ninety-one feet below the bottom of the Ohio River, showing that there is a deeply buried channel through Mill Creek Valley from Cincinnati to Hamilton; while, according to the inspector, Mr. C. J. Bates, upon building the piers for the great bridge of the Cincinnati Southern Railroad, which crosses the Ohio River near the west end of the city, it was found that the rock bottom was everywhere within a few feet of the low-water mark; thus fully justifying the inference of Prof. James, which can best be given in his own words:

". . . Previous to the Glacial period a barrier of land extended from Price Hill on the north to the mouth of the Licking River on the south, preventing the westward flow of the Ohio, and forcing it north and northwest along the channels of Mill Creek and Duck Creek. These met at Ludlow Grove (near Cummingsville) and together continued north to Hamilton. Here entered the Great Miami, and the united streams continued in great volume southward to the present channel of the Ohio, at Lawrenceburg.

"At the coming on of the Glacial period a tongue of ice projecting down the valley from the north and surrounding the Cincinnati Island, as we may call that high land now covered with