434 J. W. SPENCEK ^RELATION OF NIAGARA TO GLACIAL PERIOD 



channel to the edge of the Niagara escarpment, 3% miles northwest of 

 the Whirlpool. During the next 40 years it seems this view was not ques- 

 tioned. However, in 1881, I showed there was a lower preglacial depres- 

 sion from Lake Erie than that over the rocks of Niagara Falls, and 

 accordingly the Whirlpool-Saint Davids Valley could not have been 

 the former outlet of the Erie basin, and that Niagara is a modern river 

 throughout.^ This was the revival of the study of the science of Niagara, 

 but it is now known that there are at least three lower depressions across 

 the belt of Niagara limestones than at the falls — all of which lie beneath 

 the drift — and that the main buried outlet of the Erie basin is from 12 

 to 14 miles west of Niagara.^ At one time I conjectured that the Whirl- 

 pool-Saint Davids A^alley was preglacial. Then Dr. Julius Pohlman 

 and Prof. E. W. Claypole* wrote on this buried valley. Later I modified 

 my hypothesis and considered the buried channel as preglacial,^ which 

 view I have since maintained. However, as late as 1901, Dr. G. K. Gil- 

 bert thought that the gorge had been developed back to the Whirlpool 

 during interglacial days.^ Let us see what light is thrown on the subject. 



Features of the Whirlpool-Saint Davids Gorge 



The head of this buried canyon, for such it is, occurs at the south end 

 of the Whirlpool, some 3 miles from the edge of the escarpment. Above 

 this point is a smaller and shallower channel heading in the rocky divide 

 2 miles farther south. Be3^ond this ridge is another ancient valley, trend- 

 ing in the southward direction and deepening to 66 feet in a mile and a 

 half, at the site of the falls themselves. In this distance the buried valley 

 broadens from less than a quarter of a mile to over a mile, and gradually 

 descends a more gentle gradient throughout a longer course than that of 

 the Whirlpool-Saint Davids Gorge. This course is by way of the Falls- 

 Chippawa and Erigan valleys, as described in "Evolution of the Falls of 

 Niagara." 



2 Proceedings of the American PhilosopBiical Society, vol. xix, 1882, pp. 300-337 

 (read March 18, 1881). It was due to the inspiration of Prof. J. P. Lesley that all my 

 subsequent investigations of the physical history of the Great Lakes. Niagara, and, in- 

 deed, of the submarine valleys, were made. He was the father of the science of topogra- 

 phy and of its offsprinsr. geomorphology. 



3 .7. W. Spencer : Falls of Niagara ; their evolution and varying relations to the Great 

 Lakes : characteristics of the power and effects of its diversion. Geologic^.! Survey of 

 Canada. 1907, pp. xxxl, 490. map. 46 plates. 30 figures. 



* Pohlman : Proceedings of the American Association for the Advancement of Science. 

 1883-1887. and Transactions of the American Institute of Mining Engineers, 1889, and 

 Claypole in Science. 1886. p. 236. 



5 American Naturalist. 1887, pp. 269-271. ' 



« Gilbert : Map of Niagara River, 1901. 



