SOME OBSERVATIONS ON NIAGARA, 223 



vortex can wear away the hardest rock ; " pot-holes " and deep cylin- 

 drical shafts being thus produced. An extraordinary instance of this 

 kind of erosion is to he seen in the Val Tournanche, above the village 

 of this name. The gorge at Handeck has been thus cat out. Such 

 water-falls were once frequent in the valleys of Switzerland ; for hardly 

 any valley is without one or more transverse barriers of resisting ma- 

 terial, over which the river flowing through the valley once fell as a 

 cataract. Near Pontresina, in the Engadine, there is such a case, the 

 hard gneiss being now 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, de- 

 rived from the glacier of the Aar, and over the barrier the lake poured 

 its excess of water. Here the rock, being limestone, was in great part 

 dissolved, but, added to this, we had the action of the solid particles 

 carried along by the water, each of which, as it struck the rock, 

 chipped it away like the particles of the sand-blast. Thus, by solution 

 and mechanical erosion, the great chasm of the Fensteraarschlucht was 

 formed. It is demonstrable that the water which flows at the bottoms 

 of such deep fissures once flowed at the level of what is now their 

 edges, and tumbled down the lower faces of the barriers. Almost 

 every valley in Switzerland furnishes examples of this kind ; the un- 

 tenable hypothesis of earthquakes, once so readily resorted to in ac- 

 counting 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 Europeans had taken 

 possession of the country, the conviction appears to have arisen that 

 the deep channel of the river Niagara below the Falls had been exca- 

 vated by the cataract. In Mr. BakewelPs " Introduction to Geology," 

 the prevalence of this belief has been referred to : it is expressed thus 

 by Prof. Joseph Henry in the Transactions of the Albany Insti- 

 tute : " In viewing 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 race-way has been formed 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 pres- 

 ent site." * The same view is advocated by Mr. Hall, by Sir Charles 

 Lyell, by M. Agassiz, by Prof. Ramsay indeed, by almost all of those 

 who have inspected the place. 



A connected image of the origin and progress of the fall 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 northeast, and, after a little time, gradually resume our 



1 Quoted by Bakewell. 



