Science, Geology and Physics 



" Guide to the Geology and Paleontology of Niagara Falls and 1903 

 Vicinity," prepared by Grabau, summarizing the conclusions of u P hwn 

 all preceding geologists, for the many visitors who came to the 

 exposition and to Niagara during last year, I have to add 

 to these and to my own former studies another factor in the 

 Niagara history, namely, that the erosion of the gorge below 

 the whirlpool had been partly accomplished by a small preglacial 

 stream, which flowed along nearly the entire length of that earliest 

 part of the gorge, after draining at its head farther east probably 

 nearly the same area as the present Fish creek. Joining the St. 

 David's channel at the whirlpool, this eastern tributary undoubt- 

 edly had cut a deep ravine, with falls and cascades, along its last 

 mile or more. At the east end of the Foster flats and farther 

 upstream, the preglacial Fish creek had merely a very shallow 

 valley, slightly hollowing but not trenching the bed rocks. 



Under this view we see readily how the Niagara river with- 

 drew its waters from the low cataract at the Foster flats. On 

 reaching the head of the preglacial ravine in the gradual recession 

 of the falls, the main current, which passed on the southeast side 

 of the flats, speedily eroded a deeper channel, far below its 

 former bed above that cataract, because the drift filling the old 

 ravine was easily swept away. Along a distance of nearly two 

 miles, adjoining the Foster flats and northeasterly, the river flowed 

 afterward in powerful rapids, eroding this part of the gorge into 

 the rock strata to its present depth; and the greater depth, with 

 slow and smooth current, for a half a mile between the flats and 

 the whirlpool may be due to such deep erosion by the preglacial 

 stream there, its ravine having been cut down nearly to the bottom 

 of the St. David's channel before coming to their junction. 



Evidently the preglacial brook that coincided somewhat 

 nearly with the present Fish creek could not have passed north- 

 ward through the Niagara escarpment in the course of the river 

 gorge. The crest of the escarpment there is higher than the land 

 stretching south and southwest to the whirlpool. The gorge has 

 no widening, such as is a most remarkable feature of the old 



647 



