Glacial Boundaries

Boone County

The glacial deposits over the northern part of Boone county are unmistakable in character. On ascending the hill along the line of the Covington and Petersburg pike from Ludlow to Hebron, we encountered about one mile east of Hebron, and about 450 feet (B) above the river, a deposit of till, twelve or more feet of which in depth is exposed by a little stream running to the north. The whole surface of the country about Hebron is covered with a loamy deposit containing occasional scratched stones and granitic boulders. On ascending the hill from Taylorsville to Hebron small granitic boulders abound all along the bed of the little stream, and are found of considerable size in the clay upon the summit. On the pike between Florence and Burlington, and two miles west of Burlington, where a small tributary of Gunpowder Creek, which runs to the south, crosses the pike, a large number of granitic boulders are collected, they having been washed out of the till which caps the hills. The elevation above the river is 400 feet (B). Three-fourths of a mile to the east the elevation is 575 feet (B), and the headwaters of this tributary, a mile and a half or two miles north, near Hebron, are 500 feet (B.) I counted within a few rods of each other 15 granitic boulders, one of which measured 2$ feet in diameter. There were three or four boulders composed of metaphoric conglomerate, containing the beautiful red jasper pebbles characteristic of the eastern shore of Lake Superior, and of the region north of Lake Huron. They are identical in composition with boulders that are scattered over Michigan, Northern Indiana, and with one in the Oberlin Museum, found by Professor Allen in Brownhelm. Colonel Whittlesey brought a mass of this rock from its native ledge, near Lake Superior, on the west side of St. Mary's River, and has adorned the yard in front of his residence with it. These boulders in Kentucky are found about five miles south of the Ohio River, and south of the watershed in that part of the county.

In a drive from Petersburg to Hebron, the hills were found to be covered with till to a height of several hundred feet. The barometer read about 400 feet above the river. The redness of the soil was everywhere noticeable, showing that the iron was thoroughly oxidized. A detour to the south, from Florence to Union, and from Union across Gunpowder Creek, towards Bellevue (now called Grant P. 0.), demonstrated the absence of glacial deposits until reaching the headwaters of Middle Creek, about half way between Burlington and Bellevue. Here the tops of the hills are covered with a gravelly deposit, containing occasional granitic pebbles several inches in diameter. Near the headwaters of the southern branches of Middle Creek, and especially at Rock Spring, the deposits are of very coarse material, are of great extent, and are cemented together by an infiltration of lime like that already spoken of at Flag's Spring, and soon to be described at Split Rock. This conglomerate consists largely of pebbles of limestone, but contains also granitic pebbles. It was noticed as early as 1845 by Professor Locke, and described in the Cincinnati Gazette, and more recently by Dr. Sutton, of Aurora, who specially notices its great elevation above the river. D*r. Sutton's paper may be found in the proceedings of the A. A. A. S. for 1876, and reprinted, with additional information by Prof. E. T. Cox, in the Geological Survey of Indiana for 1878, pp. 108-113.

The most accessible place in which to study this deposit is near the mouth of Woolper Creek, about four miles northwest of the headwaters of Middle Creek, and about four miles south of Petersburg. The formation is here known as "Split Rock," and rises directly from the Ohio River, both above and below the mouth of Woolper Creek. Professor Locke "regarded this conglomerate as evidence of the destruction of a great arch of rocks which united the coal-fields of Ohio with those of Indiana and Kentucky." Mr. Robert B. Warder, in the Geological Report of Indiana, for 1872, also directs attention to this Split Rock conglomerate, and suggests, possibly, it is the terminal moraine of an ancient glacier. With this view Dr. Sutton and Professor Cox substantially agree. But Dr. Sutton and Prof. Cox suppose that the deposits upon the highland above Middle Creek are far more ancient than those in the valley of the Ohio about the mouth of Woolper Creek. As we read the facts, however, now, in the light of the most recent investigations, these deposits upon the highlands of Boone county, and at Split Rock, are probably contemporaneous, the ice of the glacial period extending down to a continuous line which crosses the river at Woolper Creek. The vast current of water which flowed down at the melting of the continental glacier, was not determined in its course by the present channels as now, for these were in many cases filled with ice, and for a time the southward flowing currents were borne completely across the channel of the Ohio, flowing in a trough of ice, whose bottom was as high as the summit of Boone county.

The pebbles in the cemented mass of Split Rock are mostly of limestone, and are very coarseā€”individual pebbles frequently being from three to four feet in diameter. Granitic pebbles are infrequent. One was found, however, measuring two feet in diameter. The cliffs of this conglomerate, at the mouth of Woolper Creek, rise not far from one hundred feet above the river, and the material is cemented together by an infiltration of lime. Kame-like ridges extend for two miles south of Woolper Creek, on the way to Bellevue. These are composed of rather fine material, and are 160 feet above the river. The terrace upon this, the Kentucky side of the river, is, for two miles or more below Woolper Creek, remarkable for its height, being more than 100 feet above the river, and 56 feet higher than the high-water mark of January 1883.

Campbell County

The glacial boundary enters Kentucky in CAMPBELL COUNTY, crossing the Ohio River about two miles north of the Pendleton county line. I have not examined sufficiently the northern part of Campbell county, and I can only fix the limit near the river. We crossed the river from New Richmond, in Ohio, and ascended through the channel of a small brook to the summit of the Kentucky hills, near Carthage. These hills are about four hundred feet above the river, and the ascent is very steep. Granitic pebbles were numerous in the bed of this small stream, and, upon reaching the summit, we found the surface covered with till to the depth of ten or fifteen feet, in which granitic boulders a foot through were numerous, and in which it was not difficult to find beautiful specimens of scratched stones. From this point we went south, keeping upon the summit of the plateau from one and a half to three miles from the river. Indications of glacial action continued, but in a somewhat diminishing degree, until reaching Flag's Spring, where they ceased entirely. But to make sure, we went on in the same direction about four miles farther, and came down to the river at Motier, without seeing any farther glacial marks. At Flag’s Spring there is an extensive accumulation of post-glacial conglomerate like that at Split Rock, soon to be described.

Kenton County

My examination of Kenton county has been too brief to be very satisfactory, but what I have seen may serve as a guide to others. Three miles southwest of Covington the hills are covered with loam from 15 to 40 feet deep, at an elevation of 400 feet (B) above the river. There are occasional small quartz pebbles in this loam; but I saw no sure signs of the actual presence of ice. In my notes I have said: "This seems like the bottom of a temporary lake when the ice dammed the river below." On going across from the pike a little south of this, so as to strike the Licking River, two miles south of Covington flats, no glacial marks were observed. At Erlanger, however, the first station south of Ludlow, on the Cincinnati Southern Railroad, a railroad cut shows clay to a depth of six feet or more containing pebbles of quartzite, limestone, and occasionally granite, near the bottom. All, however, were small, none of them more than three inches in diameter. The elevation is about five hundred feet above the river.


from George Frederick Wright's The Glacial Boundary in Ohio, Indiana, and Kentucky, 1884