364 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



ice slieet, and has published a photograph showing the section of drift over- 

 Ijdng the peat, which is here reproduced (PI. XIV, A). In this section the 

 peat is greatly concealed b}^ talus from the till, but is exposed in one place 

 up to a level several feet above the stream. Among other interesting facts, 

 Orton called attention to the occurrence of cedar berries and fragments of 

 coniferous wood in the peat and of undecomposed sphagnous mosses, grasses, 

 and sedges in its uppermost layers. Beneath the peat is a gravelly deposit, 

 in view only at the eastern or right end of the exposure, and there it is in 

 beds which dip westward at an angle of about 30°, soon passing with the 

 peat below the level of the creek bed. Wright remarks, concerning this 

 deposit, that "the appearance is that of a saucer-shaped deposit of peat, 

 such as would form in a kettle hole, and which was subsequently filled 

 and covered over with the advance of the glacier." 



At the time of the writer's visit, in 1889, no exposure of the underlying 

 gravel could be found, and no further data concerning it can be given than 

 appear in the reports by Orton and by Wright. It is not evident from 

 these descriptions whether the gravel beneath the peat is of glacial origin, 

 though there appears to be no reason for doubting- that it is, and Wright 

 evidently so considers it. The peat appears to be in situ, since its layers are 

 undisturbed and have a continuous outcrop for about 75 yards. It seems 

 scarcely probable that so large a mass would suffer removal and deposition 

 by the ice sheet without being in a more disturbed or frq,gmentary condition. 

 The drift deposits resting on the peat have a thickness of nearly 100 feet 

 and are well exposed by the undermining action of the stream. Tlie drift 

 presents a peculiar variation in color and also abrupt variations in structure. 

 The exposure is nearly one-fourth of a mile in length and extends about an 

 eighth of a mile west from the point where the peat disappears. Near its 

 western end the following series of beds are exposed: 



Section of Twin Creek Blvff, near Germantoivn, Ohio. 



Feet. 



Yellow till 8-10 



Blue till, lens-shaped in outcrop, disappearing in either direction within a few rods 0-6 



Yellow till 6-8 



Blue till 12-15 



Yellow till, local, soon passing horizontally into blue till 5-6 



Blue till 10-12 



Yellow till, local, soon replaced by sand and gravel 3-4 



Sand and gravel 10-12 



Creek bed, gravelly. 



Total, about 70 



