38 



shoe fall, being not over three feet (-9 m.) deep in the 

 deepest part and over much of the central part one foot 

 (•3 m.) or less. This fall is about 168 feet (51-2 m.) high, 

 but is about two feet (-6 m.) higher at its south edge than 

 at its north. The water does not plunge directly into the 

 great caldron or pool below, but falls upon a mass of great 

 blocks which have fallen from above. Some of these are 

 of huge size. One known as the Rock of Ages lies below 

 the southern end of the fall. 



The American Fall from Prospect point, looking south. The Horseshoe Fall in the 



distance. 



These blocks are fragments of the Lockport (Niagara) 

 limestone from the cliff over which the American fall now 

 passes ; and they rest mainly on a bench of Clinton lime- 

 stone which projects about 300 feet (90 m.) out from the 

 foot of the fall. The edge of this shelf is in line with the 

 edge of the same shelf both north and south of the American 

 fall, but except under the fall it is covered with a heavy mass 

 of talus. Under the fall the material has all been car- 

 ried away and only the great blocks remain. Elsewhere 

 the talus contains much fine material which largely con- 

 ceals the blocks. 



