SUPERFICIAL GEOLOGY OF DUNDAS VALLEY. 1 23 



present, the waters would be washing away the clay and gravel beds 

 in the neighborhood of Dundas. The softer materials, such as silt 

 and clay, forming these beds, would be carried down to the lake, 

 while the pebbles and gravel, being heavier, and requiring a greater 

 force to move, would be gradually rolled down towards the mouth 

 of the valley, afterwards to be heaped up into the position they now 

 occupy, by the storms affecting the lower and less sheltered waters 

 of what, at that time, would be Lake Ontario. 



The western slope of the beds is accounted for, by the water 

 washing over the top af the ridge and gradually moving the materials 

 over to the western side. This may also account for the wedge- 

 shape of the beds formed here and there through the ridge. 



The abrupt termination of the beds at the northern end of the 

 ridge, would lead the observer to conclude that the current down the 

 valley at the time the ridge was being laid down, set in close to the 

 eastern and southern shores of the valley, and gradually worked its 

 way over to the position it now holds at present, throwing the ridge 

 and other materials close to the eastern shore, filling up the old bed 

 with materials derived from the new. 



Another proof of this beach or ridge being laid down in com- 

 paratively deep water, is the conglomerate composing the beds and 

 also found underlying the clay, in different parts of the valley. 



This conglomerate is formed by the infiltration of the beds of 

 gravel and sand with carbonate of lime, and as the carbonate could 

 hardly pierce the heavy clays, lying in some places above the con- 

 glomerate, without leaving some traces of its having done so, it may 

 reasonably be inferred that the waters charged with the lime, were 

 flowing through the valley and depositing their charge before the 

 upper clay beds were formed. 



The carbonate of lime was derived, without doubt, from the con- 

 tinued washing of the waves against the limestones of the escarp- 

 ment, some streams of the present day being so highly charged with 

 this material, as to act upon the mosses and other vegetable matter, 

 growing within reach of their spray. It could, therefore, only be 

 after the action of the waves upon the cliffs had ceased that the 

 heavy clay deposits lying upon the conglomerate throughout the val- 

 ley were laid down. 



As no conglomerate has been found beneath the blue clay, it can 



