222 THE CANADIAN NATURALIST. [Vol. X. 



Dundas Marsh. — The eastern end of the Dundas valley con- 

 tains a large swamp, nearly three miles long, with a breadth of 

 about three-fourths of a mile, known in the early settlement of the 

 country by the name of Coote's Paradise. 



This marsh was formerly connected by a small rivulet with 

 Burlington bay, but this was subsequently closed by the G. W. 

 Kailway, when the cutting of Desjardin's canal through Burling- 

 ton heights was completed. Into this marsh all the drainage of 

 the Dundas valley is deposited, causing it to fill up at the rate of 

 one-tenth of a foot per annum. 



Burlington Heights. — Across the eastern end of the Dundas 

 swamp and some of its branches, are the Burlington heights, 

 varying from a few hundred yards to nearly a quarter of a mile 

 in width, and over 100 feet in height, which have been an old 

 beach, at a time when the lake level was at the same elevation, 

 for we find that a lake beach extends alono" the flanks of the 

 escarpment, both eastward and northward for a considerable dist- 

 ance at the same level. This is mentioned here as forming a 

 most conspicuous terrace, and as changing the physical character 

 of the western extremity of Burlington bay, and the outlet of 

 the Dundas valley. Various terraces and beaches are found, 

 both at lower levels, and also fragments at higher altitudes along 

 the side of the '- mountain," until some attain a height of 500 

 feet above Lake Ontario. 



The Grand River Valley. — The Grand river of Ontario rises 

 in the County of Grey, not more than twenty-five miles from 

 Georgian bay. Thence it flows southward, and at Elora the 

 river assumes a conspicuous feature. Here it cuts through the 

 Guelph dolomites to a depth of about 80 feet and forms a canon 

 about 100 feet in width with vertical walls. At tliis place it is 

 joined by a rivulet from the west, which has formed a tributary 

 canon similar to that of the Grand river itself. 



The country in this region is so flat that it appears as a level 

 plain. Farther southward the river winds over a broader bed, 

 and at Gait the present river valley occupies a portion of a broad 

 depression in a country indicating a former and much more exten- 

 sive valley. In fact, the old river valley existed in Preglacial 

 times, for the present stream has re-excavated only a part of its 

 old bed at Gait, leaving on the flanks of one of its banks (both 

 of which are) composed of Guelph dolomites, a deposit of Post 

 Tertiary drift, in the form of a bed of large rounded boulders 



