202 MAN AXD THE GLACIAL PERIOD. 



vation was more than four hundred feet greater than 

 now. 



The existence of an outlet at that depth seems to be 

 proved also by the fact that at Syracuse, where numerous 

 wells have been sunk to obtain brine for the manufacture 

 of salt, deposits of sand, gravel, and rolled stones, four hun- 

 dred and fifty feet thick, are penetrated without reaching 

 rock. Since this lies in the basin of Lake Ontario, it fol- 

 lows that if the basin itself has been produced by river 

 erosion, the land must have been of sufficient height to 

 permit an outlet through a valley, or canon, of the required 

 depth, and this outlet must now be buried beneath the 

 abundant glacial debris that covers the region. 



Professor Newberry, who has studied the vicinity care- 

 fully, is of the opinion that there is ample opportunity 

 for such a line of drainage to have extended through the 

 Mohawk Valley to the Hudson Eiver. But, at Little Falls, 

 a spur of the Adirondack Mountains projects into the 

 valley, and the Archaean rocks over which the river runs 

 are so prominent and continuous that some have thought it 

 impossible for the requisite channel to have ever existed 

 there. Extensive deposits of glacial debris, however, are 

 found in the vicinity, especially in places some distance to 

 the north, and in Professor Newberry's opinion the exist- 

 ence of a buried channel around the obstruction upon the 

 north side is by no means improbable. 



The preglacial drainage of Lake Huron has not been 

 determined with any great degree of probability. Pro- 

 fessor Spencer formerly supposed that it passed from the 

 southern end of the lake through London, in the western 

 part of Ontario, and reached the Erie basin near Port 

 Stanley, and so augmented the volume of the ancient 

 river which eroded the buried cafion from Lake Erie to 

 Lake Ontario. But he now supposes, though the evidence 

 is by no means demonstrative, that the waters of Lake 

 Huron passed into Lake Ontario by means of a channel 



