198 FBAGMENTS OF SCIENCE. 



by the continued action of the irresistible Niagara, 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 Earn- 

 say, 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 reach the whirlpool, trend to the north-east, 

 and after a little time gradually resume our northward 

 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 Ontario. The de- 

 clivity 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 



