Art. VI] ScHEFFEL, Orii^i/i of Sfin'/ig I'alley Gorge. 157 



of Raccoon X'allev at a point alxnit one-half mile east of S])rino; 

 Valley struck rock 'l\'^ ft. below the surface, a (k'])th (|uiti.' likely 

 approximatins^- the greatest thickness of aggraded material (smnc 

 of which, however, may represent the pre-giacial Hood ])lain), in 

 the tributary "( )1(1 X'alley." 



Spring \ alle\-, then, can not be e.\])lained as coincident in 

 origin with the devel()])ment of the ( )ld X'alley, for such an ex- 

 planation would present the incongruil\- of two ])arallel streams, 

 one tlowing- near the axis of the valley, with normal tributaries, 

 the other elevated ])ossibly over two hundred feet tlowing laterallv 

 along the eastern side in a rock gorge, if an\- possibilties of struc- 

 tural weakness or of topography could even permit the formation 

 or origin of such a stream, its course would not be maintained for 

 any long period of time. Soon a \ulnerable point in the relativclv 

 narrow west bank separating it from the old valley would be 

 discovered, and the w^aters released to take a natural course trib- 

 utary to the stream occupying the axis of the ( )ld N'alley. 



Before dismissing the topic "The Old \'alley" it mav be re- 

 marked that a theory of glacial origin due to erosional i)rocesses 

 of glacial ice is not tenable. The thickness of debris in this section 

 and its low percentage of local constituents suggest the erosional- 

 inactivity of the enclosed ice during at least the later stages of the 

 Ice Age, while protecting hills of rock in height about the same 

 as the walls of the Old X'alley, lying on the farther side of Raccoon 

 \^alley and opposite to the entrance of the Old \"allcv into the 

 latter, as well as the trend of this valley transverse to ice-move- 

 ment, oft'er irreconcilable difficulties to any theory of active ero- 

 sional processes in this section during anv glacial epoch. 



Also the topography of the valley, its great width relative to 

 its length, and the great depth to bed rock, is indicative of an 

 earlier drainage line, a line continuing daring such a long interval 

 of time that this area was ])robably reduced to a mature conditioii 

 with erosional processes declining in a rapidly changing ratio as 

 cutting ])roceeded. At the period of its history just before gla- 

 ciation this Old X'alley may be regarded as having about as nearlv 

 approximated a condition of base-level as its distance from the 

 sea would permit.' This evidence of maturity in the Old X'allev 



1 Davis, "Base Level. <?i-iHle niid I'eneplnin," .Tmirnal of Geology, Vol. 10 

 (1902), pp. 77-111. 



