6Q THE CANADIAN NATURALIST. [Vol. X. 



Basin of Lake Erie. The exceedingly shallow basin of Lake 

 Erie has its bottom as near a level plane as any terrestrial tract 

 could be. Its mean depth, or even maxima and minima depths 

 from its western end for more than 150 miles, scarcely varies 

 from 12 or 13 fathoms for the greater portion of its width. The 

 eastern 20 miles has also a bed no deeper than the western por- 

 tion. Between these two portions of the lake, the hydrography 

 shows an area with twice this depth (the deepest sounding being 

 35 fathoms). This deepest portion skirts Long Point (the ex- 

 tremity, a modern peninsula of lacustrine origin), and has a 

 somewhat transverse course. An area of less than 40 miles Ions; 

 has a depth of more than 20 fathoms. The deeper channel seems 

 to turn around Long Point, and take a course towards Haldimand 

 county, in our Canadian Province, somewhere west of Maitland. 

 The outlet of the lake, in the direction of the Niagara river, has 

 a rocky bottom (Corniferous limestone). 



The study of this lake at first appears less practicable than 

 that of Ontario, but, when its former outlet and its tributary 

 rivers are described, the writer trusts that he will have made 

 some observations, that may help to clear the darkness that hangs 

 about the history of our interesting lake region, before the advent 

 of the Ice Age. 



The Dimdas Valley and adjacent Canons. We may consider 

 that the Dundas valley begins at the "bluff" east of the Hamil- 

 ton reservoir, and extends westward, including the location of the 

 city of Hamilton and the Burlington Bay, at least its western 

 portion. With this definition, the width at the Burlington heights 

 (an old lake terrace 108 feet above present level of the water) 

 would be less than five miles. At a mile and half westward of 

 the heights, the valley suddenly becomes narrowed (equally on 

 both sides of its axis of direction, by the Niagara escarpment 

 making two equal concave bends, on each side of the valley, 

 whence the straight upper portion extends, the whole resembling 

 the outline of a thistle and its stem), from which place it extends 

 six miles westward to Copetown, on the northern side ; and three 

 and a half to Ancaster, on its southern side. The breadth be- 

 tween the limestone walls of this valley varies somewhat from 

 two to two and a half miles. The summit angles of the lime- 

 stone walls on both sides are decidedly sharp. 



Dundas town is situated in this valley, its centre having a 

 height about 70 feet above Lake Ontario, but its sides rise in 



