NIAGAKA. 197 



a hard gneiss being there worn away to form a gorge, 

 through which the river from the Morteratsch glacier 

 rushes. The barrier of the Kirchet above Meyringen is 

 also a case in point. Behind it was a lake, derived 

 from the glacier of the Aar, and over the barrier the 

 lake poured its excess of water. Here the rock, being 

 limestone, was in part dissolved; but added to this we 

 had the action of the sand and gravel carried along by 

 the water, which, on striking the rock, chipped it 

 away like the particles of the sand-blast. Tims, by 

 solution and mechanical erosion, the great chasm of the 

 Finsteraarschlucht was formed. It is demonstrable 

 that the water which flows at the bottoms of such deep 

 fissures once flowed at the level of their present edges, 

 and tumbled down the lower faces of the bairiers. 

 Almost every valley in Switzerland furnishes examples 

 of this kind ; the untenable hypothesis of earthquakes, 

 once so readily resorted to in accounting for these 

 gorges, being now for the most part abandoned. To 

 produce the Canons of Western America, no other cause 

 is needed than the integration of effects individually 

 infinitesimal. 



And now we come to Niagara. Soon" after Euro- 

 peans had taken possession of the country, the con- 

 viction appears to have arisen that the deep channel of 

 the river Niagara below the falls had been excavated 

 by the cataract. In Mr. Bakewell's ' Introduction to 

 Greology,' the prevalence of this belief has been referred 

 to. It is expressed thus by Professor Joseph Henry in 

 the c Transactions of the Albany Institute : ' l 'In view- 

 ing the position of the falls, and the features of the 

 country round, it is impossible not to be impressed with 

 the idea that this great natural raceway has been formed 



1 Quoted by Bakewell. 



