36 



7 miles (11-3 km.) from the south shore of the lake but rises 

 in places 380 feet (115-8 m.) above it, or 625 feet (190-5 m.) 

 above the sea, the elevation of Lake Ontario being 245 or 

 246 feet (74-7 or 75-0 m.). 



The basin of Lake Ontario is not symmetrical, since the 

 deepest soundings occur near the south shore, where depths 

 of 400 or 500 feet (121 -9 or 152 -4 m.) are frequently found. 

 The greatest depth recorded is 738 feet (224-9 m -)> so that 

 the bottom goes 492 feet (151 m.) below sea level. The 

 basin was probably once a river valley, its northeastern 

 end at the Thousand islands having been warped up at the 

 close of the Ice age. 



Lake Ontario to Niagara Falls. 



The Lower Niagara River — Approaching the mouth 

 of Niagara river, the steamer crosses what is supposed to 

 be a submerged delta of Niagara river called Niagara bar. 

 Its front descends to a depth of over 200 feet (60-9 m.) 

 quite steeply. The depth of the water on it varies from 

 less than 15 feet (4-6 m.) to about 40 feet (12-2 m.). 

 Many soundings in the shallower part show "rocky" 

 bottom, so it is not certain that it is all a delta deposit. 



The banks of Niagara river below the gorge are steep 

 and rise from a height of 20 to 30 feet (6 to 9 m.) near the 

 lake to 125 feet (38-2 m.) at Lewiston. The average width 

 is about 2000 feet (610 m.). The banks are red shale with 

 thin drift on top, but two miles (3-2 km.) south of Niagara- 

 on-the-lake the rock disappears and the banks on both 

 sides are wholly of drift for about a mile. This is probably 

 an old river channel of inter-glacial or pre-glacial age and 

 has been regarded by some as a possible continuation of 

 the buried St David gorge. A sharply cut terrace 20 to 

 25 feet (6-1 to 7 • 6 m.) above the river at the Stella Niagara 

 school, two miles north of Lewiston, is an abandoned 

 portion of the old bed where the river flowed at a higher 

 level than now. It is floored with coarse gravel and cob- 

 bles, which show in the bank. Just opposite, on the 

 Canadian side, there is another fragment of old channel at 

 a slightly higher level. This is three-fourths of a mile 

 (1 -2 km.) long, relatively narrow and the outer part of its 

 course is about one-third ( • 5 km.) of a mile from the river. 



