and the Geology of the Surrounding Country. 113 



stream. At one place, however, about a mile below the fall, 

 and where the channel is narrowest, the stream glides along 

 with comparative quiet, while below this, where the channel is 

 broader, it is thrown into great confusion. Again, below the 

 whirlpool the surface of the river is more smooth, and the 

 current more gentle, though the channel is narrower than 

 above. The cause of these appearances, which have seemed 

 inexplicable upon the common theory, and have been used as 

 arguments against the recession of the falls, is to be sought in 

 the geological structure of the place. It will be seen that 

 below the whirlpool there are no hard rocks in the bed of the 

 river, and consequently the channel is deeper than where such 

 rocks exist. At the whirlpool, and above that place, the hard 

 sandstone, No. 2, is at and near the level of the river, and 

 consequently the channel is not worn so deep. Again, after 

 this hard mass has dipped beneath the surface, the channel is 

 excavated in softer rocks ; hence the narrow channel and 

 smooth water a mile below the falls. Near the falls, the 

 higher beds of sandstone and the Protean limestone come to 

 the level of the river, and thus cause a wider, shallow channel, 

 and more tumultuous water. Such, simply, I conceive to be 

 the explanation of the variable width of the chasm, and the 

 greater or less violence of the water. 



Upon the west bank of the river, at the whirlpool, there is 

 a depression, and a deflection in the course of the river to the 

 right, as will be seen by referring to the map. Standing 

 upon the east bank of the river, this depression has the ap- 

 pearance of having been worn by the eddying current of the 

 stream ; but on farther investigation it proves to be of differ- 

 ent origin. During a recent visit, in company with Mr. Lyell, 

 we examined this place, and found it to be an ancient gorge, 

 filled with drift, except a narrow ravine through which a 

 small stream flows into the river. This stream may be traced 

 in a north-west direction for two miles, where it comes to the 

 level of the surrounding country. In one or two places, near 

 the river, the bed of this stream has laid bare the rocks, 

 which proves that they are not excavated so deeply as the bed 

 of the Niagara. From the termination of this ravine, upon 



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