Art. VI] ScHEKFEL, Orii^in of Sprifi}:; Valley Gorge. 165 



Old Valley on both the west and north exposures, Icavins;" a chan- 

 nel between the rock and ice. This channel would alTord a ready 

 outlet for ice-front waters, and with the ice maintaining a per- 

 manent position, the gorge cutting would proceed rapidly. After 

 a certain period of time, a period determinable by the volume of 

 glacial waters and its cutting tools, a channel would be developed 

 which, by incising the solid rock of the valley wall, might become 

 fixed for an indefinite period. 



The large number of big granite bowlders found, especially 

 near the outlet end of the Spring Valley course, is indicative of 

 the vigor of this late glacial drainage. This circumstance also 

 supports the theory, later elaborated, that Spring \'alley drainage, 

 while the ice maintained its position in Raccoon \'alley. took a 

 course eastward around the north end of the Old A'alley wall ; 

 the lowering in the velocity of the water near the turn would 

 cause the heavier part of its load to be dropped. 



The stratigraphy of the Black Hand rock also favors the late- 

 glacial theory ; of sandy shale-like character, with numerous joints 

 and bedding planes ' both normal weathering and the removal of 

 large blocks of stone would be facilitated.' 



While on the western slope of the east wall of the Old \^alley 

 the waters soon cut a channel into the rock so far that a guarding 

 boundary of ice was no longer essential, it is probable that towards 

 the northern end the ice constituted one bank of the stream for a 

 longer period of time. Here the conditions differed, the stream 

 channel, being parallel to the direction of ice movement in the 

 Raccoon Valley, could maintain its position even while the ice 

 tongue was retreating. 



The theory that this drainage line after emerging from Spring 

 Valley continued its course around the end of the valley wall as 

 before suggested constitutes in itself a problem. There are sev- 

 eral facts in accord with such an explanation. The steepness of 

 this slope indicates but little weathering. If this steep condition 

 had been produced pre-glacially it would present a more mature 

 appearance, and if eroded by ice the tendency would have been 

 to accentuate such a condition. There is, moreover, practically 



' Carney, "Geology of Perry Township, Licking County. O." Bulletins Scien- 

 tific Laboratories, Denison University, Vol. XIII (1900). p. 120, VI?,. 



- Westgate, "Abrasion by Glaciers, Rivers and Waves," Journal of Geology, 

 Vol. XV (1907), pp. 116, 117. 



