GLACIAL SUCCESSION IN OHIO. 139 



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 con- 

 tents of this muck -bed seem, therefore, to indicate an inter- 

 glacial 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 thick- 

 ness 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, there- 

 fore, 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 form- 

 ation 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 gaster- 

 opod shells obtained from this silt by Dr. Welch await specific 



