306 THE CANADIAN NATURALIST. [Vol. X. 



The beaches at the higher levels are composed of much more 

 local dehrls thaa those at 116 feet and at the present water level, 

 about the western end of Lake Ontario now to be described. 



BurUngtou Heights and Burlington Beach. — The lower part 

 of the Duodas valley and the site of Burlinjiton bay were exca- 

 vated out of the Erie clay during the period of elevation of land 

 that followed that epoch, and the interglacial Grand river flowed 

 down this valley in the same way that the Niagara river flowed 

 down the St. David's valley. These valleys became closed, how- 

 ever, during the deposits of the Saugeen clay and the terraces 

 (the visible surface for a depth of 200 feet in the St. David's 

 valley shows only stratified sand, and was not closed up by glacial 

 action as has been suggested). Therefore the deposits of Bur- 

 lington heights (and the 116 feet terrace) were not brought down 

 the Dundas valley. Moreover, I have never seen a solitary 

 Niagara pebble in this terrace, though sought for. Again, the 

 Hudson river pebbles in the Dundas beaches at higher levels are 

 all very small, whilst both the 116 feet terrace and the present 

 lake beach contain some strata of cobble stones from four to six 

 inches in diameter, with oval (water-worn) slabs from one to two 

 feet lonu'. The materials of these beaches have all been derived 

 from the debris of Hudson river rocks and contain a small quan- 

 tity of crystalline pebbles of moderately small size. The nearest 

 exposures of Hudson river rocks is at Oakville (20 miles distant), 

 but at a lower level. However, at Weston (30 miles distant) west 

 of Toronto, the same rocks occur at 179 feet (and lower) above 

 Lake Ontario. The shape of the pebbles is flattened oval, they 

 were evidently derived from these northern exposures and trans- 

 ported around the whole western end of the lake to form the 

 conspicuous terrace of 116 feet and the present beach. This 

 transportation has been efl"ected by the action of the waves and 

 floating coast ice when the water was at the respective levels. 

 The present beach may have been in part derived from the 

 denudation of that 116 feet. 



Burlino-ton Heights forms the extreme western end of the bay 

 of the same name and the Burlington beach, the end of Lake, 

 Ontario. The Heights, varying from less than a quarter of a 

 mile to a few hundred yards in width, separates the Dundas 

 marsh (at the same level) from Burlington bay. The width of 

 the marsh here is about half a mile. At the northern end, it 

 was formerly connected with the bay by a ravine partly filled by 



