26 



known as the Old Narrow section and is a little more that 

 a mile long. Its average top width is about 1,300 feet 

 (400 m.). The talus slopes are fully twice as wide in 

 these two old sections as the average in the newer sections. 

 This is partly due to greater age and longer weathering, 

 partly to thinner capping limestone and partly to the 

 exposure of nearly 100 feet (30 m.) more of shale in the 

 gorge walls here than in those above the head of Foster's 

 flats. Spencer's soundings show a depth of 150 feet (45.7 

 m.) about 1,000 feet (304 m.) from the mouth of the 

 gorge in the middle of the first section, but the Old Narrow 

 section, judged by the few soundings available and by the 

 behaviour of the water, is on the average less than 100 feet 

 (30 m.) deep. In these older parts of the gorge the recent 

 rise of the level of Lake Ontario has backed the water up 

 into the gorge, slackening the current and increasing the 

 depth. On this account the water stands somewhat 

 higher and covers the lower part of the talus slopes. In 

 the lake history this section of the gorge correlates with 

 the Kirkfield stage of Lake Algonquin. It was originally 

 made narrow and not so deep as now, for the cataract 

 then carried only the discharge of Lake Erie, and Lake 

 Iroquois stood about 75 feet (23 m.) higher than the 

 present surface of Lake Ontario. 



The Lower Great Gorge. 



This section extends from the bend below Niagara 

 university, where the gorge widens, to the upper side of 

 the Eddy basin, but does not include the whirlpool. Its 

 width between the cliff lines from the bend up to a point 

 about 1,000 feet (30 m.) above the head of Foster rapids 

 averages more than 1,600 feet (490 m.), and at the widest 

 is about 1,825 feet (560 m.). It is also characterized 

 by shallowness to the upper end of Foster's flat. Above 

 the north end of Wintergreen terrace the width is 1,300 to 

 1,500 feet (400 to 460 m.), and shallowness gives 

 place to greater depth at the upper end of Foster's flat. 

 Frbm the point of view of gorge characters alone, these 

 variations of width and depth are not easily explained. 

 But in the light of the lake history their causes 

 seem clear, and although they might seem to furnish 

 good ground for subdividing this section, the lake 

 history shows that they are not of that order 



