352 -''>..' 



the Tonawanda and other large tributaries coming in at right angles to the 

 consequent streams are the subsequent streams and some of their valleys 

 are now the basins of the Great Lakes. 



Short gullies, or tributaries to the subsequent streams, called obsequent 

 streams, worked headward into the cliffs of the cuestas. Such a stream 

 was the St. David's gorge, which, however, was not the pi-eglacial Niagara, 

 as was once believed by Scovell, Pohlman (84) and others. 



The direction of preglacial drainage postulated by the theory above is 

 in accord with the theories of Upham (128), Westgate (137), Russel (88), 

 and also A. W. G. Wilson, who has worked the preglacial drainage of the 

 region east and north of Lake Ontario in detail (140) (Plate VI). 



