6 4 



falls at that time was extremely flat and broad. A shallow 

 trough leads southwest and south from Smeaton ravine 

 to the old river floor north of Foster's flats. Across 

 this a part of the river found its way for a long enough time 

 to carve out the small ravine which was in all probability 

 300 or 400 feet (90 to 120 m.) longer than now, when it 

 was first made, the main gorge walls having weathered 

 back this much since then. It does not seem possible 

 that this side ravine could have been made during the 

 preceding Kirkfield stage of Lake Algonquin, when the 

 volume of Niagara river was small. 



The Oldest Gorge Section. — At about one-quarter 

 of a mile (-4 km.) north of Smeaton ravine, the cliff line 

 and the railway turn towards the northwest. Fine views 

 into the gorge and out of its mouth over Lewiston and the 

 Ontario plain are obtained here. The cliff lines are more 

 irregular north of this point and the top width of the gorge 

 is a little greater. Near the mouth of the gorge the walls 

 are about 350 feet (106 m.) high, the capping limestone 

 is only about 20 feet (6 m.) thick and over 100 feet 

 (30 m.) more of shale is exposed. All of these factors 

 favour more effective weathering and cliff recession and 

 have produced wider talus slopes than in the newer parts 

 of the gorge. The average top width for a little more than 

 a mile north of the university is only a trifle less than the 

 average width of both of the great gorge sections above. 

 But the narrowness of this section at its bottom, coupled 

 with the characters mentioned, indicates that it was origi- 

 nally narrow and not so deep, having been deepened largely 

 in later times by the long wearing action of rapids or small 

 cataracts and not by a great cataract. The gorge charac- 

 ters indicate that the river had a relatively small volume 

 while making this section, which corresponds with the 

 Kirkfield stage of Lake Algonquin, when Niagara had only 

 the discharge of Lake Erie. 



There is no great change in the characters of the 

 gorge north of Smeaton ravine, but the point where it 

 widens slightly [about 2,000 feet (600 m.) south of the 

 mouth] is taken as a division point, not only on account 

 of the slight widening and more irregular cliff line, but 

 because other facts, showing the divided volume of the 

 first flow of Niagara and the relatively brief duration of 

 that condition, point to the same place. This point, if 

 correctly identified, marks the time in the lake history 



