470 THE CANADIAN NATURALIST. [Vol. vii. 



gravels, and sands, from the lake, in the more quiet waters, 

 where the opposite currents of the river and lake met. 



The ridge of Burlington Heights is not a moraine caused by 

 the deposition of boulders and pebbles carried down the valley 

 by glaciers and field-ice ; but the material was brought from the 

 Hudson River deposits on the north side of the lake westward 

 by the waves, or assisted by the action of field-ice drifting on the 

 waters of the lake. 



In the excavation through this ridge, during the construction 

 of the Desjardins canal, the antlers of a wapiti (iJervus Canaden- 

 sis) and the jaw of a beaver {Castor fiber') were obtained at a 

 height of 77 feet above the lake, while seven feet below, several 

 bones of the mammoth (^Euelephas Jacksoni) were found. 



Farther eastward is the Burlington Beach, the present lake 

 shore, separating the bay of that name from Lake Ontario. This 

 consists of a sand-bar, half a mile wide, extending across the 

 bay, with an opening for the discharge of the waters into the 

 lake, by means of the Burlington canal, which is the enlarge- 

 ment of a former outlet. The pebbles of the gravel are not 

 usually large, and consist mostly of oval Hudson River frag- 

 ments, together with small ones of Laurentian age. 



The streams flowing down tributary ravines, which in several 

 places are deeply cut into the Niagara escarpment, have swept 

 away any of the deposits of Erie clay which may have filled them 

 at a former time. The erosive action did not cease when it had 

 formed the beds of the streams, but is constantly wearing away 

 the soft Medina and Clinton shales, and allowing the harder 

 dolomites of the Niagara to fall, so that the beds of the streams 

 are strewn with masses of rock, the largest of which would prob- 

 ably weigh as much as fifty tons. In some of the gorges calca- 

 reous tufas are being formed, and in places mosses, leaves, and 

 fragments of wood are being calcified. Some of the tufa beds 

 have attained a thickness of no less than from one and a half to 

 two feet. 



From the difi"erent water-margins which exist so much above 

 the present lake shore, it is evident that there has been a gradual 

 recession of the waters, due either to a subsidence of the lake 

 from a deepening of its outlet, or to an elevation of the land. 

 The evidence obtained goes to show that it is due chiefly to the 

 latter cause. During the deposition of the Erie clay, the land 

 must have subsided about 400 feet, and the subsequent re-eleva- 

 tion appears to have been about 300 feet. 



