136 SUPERFICIAL GEOLOGY OF DUNDAS VALLEY. 



upper beds of the Onondaga group, while the southern side would 

 be partially left open for the connection with Lake Erie by the Grand 

 river, to which, we have already seen, all the streams in the district 

 are tributaries, 



The deposits forming the upper beds of drift in the valley pro- 

 per correspond very nearly to those in the region which we have 

 just shown to be the bed of the post-glacial lake. The sands and 

 clays, brown and blue, are present in many places in regular order> 

 thus showing in a pretty conclusive manner that the operations con- 

 cerned in the formation of the one were also actively engaged in the 

 construction of the other. 



This district has also its bounds shown — the three sides, the 

 escarpment, and the fourth we have already assumed to be Burlington 

 Heights partially, or it may have been occasioned by the retiring 

 glacier damming up the waters in the valley and forming a lake. 



The valley proper has, however, several features altogether want- 

 ing in the district to the west. In the western district just described, 

 I have not in any instanee seen any boulders or fragments of native 

 rocks. Boulders of any kind are not very plentiful and those generally 

 found are altogether rounded and water-worn granites. 



Well-diggers and the farmers of the district assure me that the 

 underlying clays whenever pierced are absolutely free from stones. 

 Of course, in a wide district like this and the small holes usually made 

 by the diggers, it would be a strong assumption to say there were no 

 stones to be found in the clays. On every farm there is at least one 

 well, and on some farms two or three, many or most of which have 

 entered the blue clay. When these numerous diggings fail to show 

 stone, we may assume that stones are by no means ot frequent occur- 

 rence in the district. Beds ot gravel are also reported as being absent. 



Now, the condition ot the underlying blue clays of the valley is 

 altogether different. 



The borings in many places report the underlying clays to be 

 literally packed with stone, and limestone fragments in nearly every 

 case. 



Beneath the upper bed of the blue clay, gravel and shingle are 

 of frequent occurrence. These again in some places are underlaid 

 by a lower bed of blue clay. The blue clays in the head of the valley 

 lie upon the rock, while the beds of the same material towards the 



