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Re-elevation of the land. Between the deposition of this silt and the formation of the outer moraine of the later drift, the altitude appears to have become about as great as at the present, since, as shown below, the gravels deposited at that time along valleys leading away from the ice margin bear witness of vigorous drainage.

Outer moraine of the later drift. Since the position of this moraine is indicated on the accompanying map, it need to be outlined. It should, however, be stated that this moraine is overridden by a later one a few miles east of Hillsboro, Ohio, and has not been recognized in the eastern part of the State. The moraine consists of a ridge of drift one to two miles or more in width, standing, as a rule, but twenty to forty feet above the outer border plain. Its surface is gently undulating, there being but a few sharp knolls or ridges, such as characterize the surface of a later series of moraines described below. It is composed mainly of till, though gravel deposits are not infrequent, either in the low knolls or in beds or pockets incorporated in the body of the drift.

Striæ are numerous in the district immediately north of this moraine, and since the usual bearing is toward the moraine and not toward the glacial boundary, it seems evident that they were produced at the time of the later invasion. Some striæ near Cambridge City, Indiana, appear to be out of harmony with the ice-movement of the later invasion, and may, therefore, be older.

The older drift was but partially removed by this later invasion, and it is frequently encountered in wells and exposed in bluffs of streams. It is harder and dryer than the newer drift. In a few places, notably at Marshall and Martinsville, in Highland county, and in the vicinity of Wilmington, in Clinton county, a black soil is found at the base of the newer drift. I have seen it only at Wilmington, but Prof. Orton, in his report on Highland county, calls attention to its occurrence at Marshall, and I was told by well diggers of its occurrence in Martinsville. In Wilmington it is exposed in a railway cutting near the public school building, in the west part of the village. It consists