198 FRAGMENTS OF SCIENCE. 



the idea that this great natural raceway has been 

 formed by the continued action of the irresistible Niag- 

 ara, and that the falls, beginning at Lewiston, have, in 

 the course of ages, worn back the rocky strata to their 

 present site.' The same view is advocated by Sir 

 Charles Lyell, by Mr. Hall, by M. Agassiz, by Professor 

 Ramsay, indeed by most of those who have inspected 

 the place. 



A connected image of the origin and progress of 

 the cataract is easily obtained. Walking northward 

 from the village of Niagara Falls by the side of the 

 river, we have to our left the deep and comparatively 

 narrow gorge, through which the Niagara flows. The 

 bounding cliffs of this gorge are from 300 to 350 feet 

 high. We reached the whirlpool, trend to the north- 

 east, and after a little time gradually resume our north- 

 ward course. Finally, at about seven miles from the 

 present falls, we come to the edge of a declivity, which 

 informs us that we have been hitherto walking on 

 table-land. At some hundreds of feet below us is a 

 comparatively level plain, which stretches to Lake On- 

 tario. The declivity marks the end of the precipitous 

 gorge of the Niagara. Here the river escapes from its 

 steep mural boundaries, and in a widened bed pursues 

 its way to the lake which finally receives its waters. 



The fact that in historic times, even within the 

 memory of man, the fall has sensibly receded, prompts 

 the question, How far has this recession gone? At 

 what point did the ledge which thus continually creeps 

 backwards begin its retrograde course? To minds 

 disciplined in such researches the answer has been, and 

 will be At the precipitous declivity which crossed the 

 Niagara from Lewiston on the American to Queenston 

 on the Canadian side. Over this transverse barrier the 

 united affluents of all the upper lakes once poured their 



