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of black muck, several inches in thickness, overlain by till, and underlain by a yellowish sandy clay. The exposure only extends a foot or so beneath the muck, hence but little is known as to the character at this point of the underlying drift sheet. Dr. Welch, of Wilmington, has found pieces of coniferous wood imbedded in the soil in this and other exposures in that vicinity. He has preserved one piece which shows beaver cuttings. He has also discovered seeds of various plants imbedded in the muck, some of which now flourish only in higher latitudes. The contents of this muck-bed seem, therefore, to indicate an interglacial climate less genial than the present.

In his report on Montgomery county, Ohio, Professor Orton described a buried peat-bed exposed in the bluff of Twin creek, near Germantown. This peat contains the berries and fine twigs of cedar. At the time of Professor Orton's visit, in 1869, the peat was exposed for a distance of forty rods, and had a thickness of twelve to twenty feet. It was underlain by a bed of gravel. At the time of my visit, in 1889, its exposed thickness above the creek bed was about eight feet. It would seem, therefore, that the peat deposit has a somewhat lower altitude where now exposed than where Professor Orton saw it. Professor G. F. Wright, who has also seen the peat-bed, has suggested (Bull. U. S. Geol. Survey, No. 58, pp. 96-97) that it occupies a large kettle-hole, and that the higher portions of the peat-bed were near the rim. This peat-bed is overlain to a depth of 90 to 100 feet by a fresh-looking drift, mainly till, and evidently of the newer drift series. This locality is north of a later moraine than the one under discussion. It is not known whether the peat was accumulated during an interval of deglaciation between the formation of that moraine and the later one, or at an earlier time. The later interval seems to have been sufficiently protracted for the accumulation of this amount of peat.

Several wells in the east part of Wilmington have passed through a fossiliferous silt between the newer till and an older drift-sheet at a depth of about thirty feet. A few minute gasteropod shells obtained from this silt by Dr. Welch await specific