214 PEOCEEDINaS OF THE GEOLOGICAL SOCIETY. 



broad reach, like that above the Ealls. It is on a continuation of 

 this platform, about a quarter of a mile below Clifton House, be- 

 tween the drift-terrace and the edge of the gorge, that the strata 

 containing existing river-shells occur (fig. 6). 



Fig. 6. — Section showing the position of the Freshwater beds above 

 the Gorge of the Niagara. 





1. Freshwater beds. 



2. Drift, with boulders. 

 'y~'^^*r 3. Niagara Limestone. 



-^ 4. Niagara Shale. 



5. Talus. 



This drift-terrace Sir Charles Ljell has shown to be as old as the 

 Mastodon-period. The freshwater beds lie in a shallow hollow on 

 the limestone. They consist of remodelled drift, and some of the 

 stones are scratched ; but whether the scratches made in the older 

 drift-period have not been worn away, or whether the stones were 

 scratched by river-ice is uncertain. The floor of Niagara limestone 

 is here deeply furrowed, the striations and minor scratches crossing 

 each other at various angles ; but the majority runfS. 30° "W. They 

 foUow the general direction of the other striations of the country, 

 that underlie the drift. 



On Goat Island, Sir Wm. Logan and I observed that the fluviatile 

 strata lie on drift, — a circumstance, I believe, not previously noticed. 

 It consists, at the base, of sand; and above, of clay horizontally and 

 evenly bedded, containing scratched stones and boulders. As shown 

 in Sir Charles Ly ell's diagram*, at the eastern end of the island the 

 Magara limestone rises a few feet above the river, in the still re- 

 cesses of which are numerous living shell-fish. Between this point 

 and the summit of the island overlooking the Palls, there is a gradual 

 fall of 15 feet, showing the slope of the river-bed when Goat Island 

 was covered with water. The drift at this point is 29 feet thick, 

 and the freshwater beds above 10 feet, giving 39 feet for the height 

 of the island above the water at the edge of the Falls. Allowing a 

 dip of '2^h feet in a mile for the general dip of the limestone. Goat 

 Island was covered with water when the Falls were probably about 

 one mile and a haK further down than at present. With regard to 

 the retrocession of the fall, as might be expected, its rate is fastest 

 when the body of falling water is greatest, this cause of waste 

 being far more powerful than the winter's frost. Towards the base 

 of the edges of the Horse-shoe FaU, and at the American Fall, 

 blocks of limestone are accumulated in great heaps, while in the 

 middle of the Horse-shoe Fall the turmoil is so great that it scoops 



*■ Travels in North America, vol i. p. 37. 



