156 Bulletin of Laboratories of Denison University. Vol. xill] 



the Old \'alley referred to above, wliich includes within its bound- 

 aries nearly all the data given. 



THE OLD VALLEY.' 



That the Old Valley is of pre-glacial origin is obvious. If the 

 walls were of glacial debris, a post-glacial theory might obtain ; 

 but while the floor is covered with a heavy glacial deposit, rock 

 of the Black Tland formation outcrops in corresponding horizons 

 near the Raccoon ends of the east and west walls, and also at 

 points on the western side near the valley head. It is equally 

 clear that originally the valley was deeper than at present, as it 

 has been partially filled with drift.' Its situation was particularly 

 favorable for such accumulation. Overridden by ice, as shown 

 by glacial accumulations on the highest parts of its walls, the situ- 

 ation with respect to glacial-motion ( from the north and north- 

 west) was particularly favorable for holding a mass of ice as in 

 a pocket, retarding onward progress, and admitting continuous 

 accessions to take the place of the ice melted. 



That such a process continued during a long period of time, 

 and very effectively from a depositional standpoint, is evidenced 

 by the great depth of debris in the valley. Data for many portions 

 was not available. Among such portions may be included the val- 

 ley divide on its eastern wall and also the southern end of this 

 wall which present peculiar phases suggestive of old and new 

 drainage complications, a discussion of which would not be rele- 

 vant to this article. Above the exposed rock walls a thin deposit 

 of drift varying in depth in accordance with simple topographic 

 laws is found. At the point marked W on Fig. 1, where a 145 

 foot well was drilled two years ago, 136 feet of drift was 

 penetrated before rock was reached. The point mentioned is but 

 a short distance from the valley wall where rock outcrojis in a 

 drainage bed, with only about 15 ft. of debris above it. This 

 would indicate a far greater thickness of deposit in the lower part 

 of the valley course. None of the wells in this section abenit which 

 information was obtained are as deep as the one above mentioned, 

 nor do they reach the rock, but a gas well drilled in the flood plain 



1 Levorott, U. S. Moiionrai)!! XL! (1!K>2|, p. 172. 



' AVrig-ht refers to drift about Granville in liis "The loe Age in North 

 America" (1891), pp. 468, 493. Cut on p. 284. 



