and the Geology of the Surrounding Country. 127 



river, requires for its elucidation the existence of water stand- 

 ing at a level somewhat higher, in order to allow of the de- 

 posit being made in the bed of the stream. To accomplish 

 this, a barrier is required further north than the whirlpool, 

 and about the height of the surface of limestone between this 

 and Lewiston. The occurrence of successive terraces below 

 this one, proves that the drainage to the present point was not 

 effected suddenly. 



There is another fact which should be noticed, as proving 

 the existence of a current from south to north, during the de- 

 position of the materials forming Goat Island. The pebbles, 

 at least large numbers of them, are of the limestone of Black 

 Rock, and the harder layers of the saliferous formation, like 

 the rock in place at the upper end of Grand Island. The 

 surface of the rock, on which the deposit forming Goat Island 

 is made, is smoothed and scratched, as are the surrounding 

 surfaces both in the rapids and on either bank of the river. 

 The deposit is of greatest thickness towards the fall, and thins 

 entirely out at its eastern extremity. 



There is another indentation on the eastern bank of the 

 Niagara, below the whirlpool. This has been cited as a case 

 where the small stream coming in, is insufficient to account 

 for such an excavation.* It occurs at the junction of Bloody 

 run and the river, and bears the strongest evidence of having 

 been produced by the common agents, frost and water. The 

 wearing action of the stream alone is probably insufficient to 

 produce this short ravine, which extends a few rods back from 

 the margin of the river bank ; but when we take into con- 

 sideration the fact that the water penetrates all the fissures of 

 the rock, and then, during fall and winter, expands by freez- 

 ing, we shall find means of explaining the mode of operation. 

 At the falls, the recession is by the undermining and breaking 

 down of the upper masses ; the action of frost is not to be 

 taken into consideration, as the water never freezes. Now I 

 consider it as an established fact, that small streams, which 

 freeze during winter, will excavate their beds more rapidly 



• Am. Journal of Jscience, Vol. XXXV, No. I. 



