108 SUPERFICIAL GEOLOGY OF DUNDAS VALLEY. 



where it thins outs and is replaced by stratified beds of stiff clay con- 

 taining inter-stratified beds of quicksand. These beds of clay grad 

 ually deepen to the banks of the Grand River. At Middleport on 

 the Grand River, the clay beds are between ten and fifteen feet 

 above the surface of the river, and at Onondago, a few miles further 

 up the river, the beds are about thirty feet higher. At both places, 

 there are inter-stratified beds of sands, containing shells of recent 

 species. At Onondago the drift is 78 feet thick, and the river flows 

 through it about 35 feet above the rock bed. 



In addition to the large swamp already mentioned as lying on 

 the top of the height of land, there are numerous small cup-shaped 

 swamps lying among the sand hills on the eastern side of the ridge. 

 On Fairchilds Creek, at Mud Run, I found shells of recent species 

 in a small bed of sand enclosed in heavy beds of clay. The .sand 

 occupies a position between the white colored and bluish clays. 

 The white is twelve feet thick, and the blue four feet before reach- 

 ing the water level. * There is, therefore, twelve feet of clay above 

 this six inches of sand. This clay and sand is apparently the 

 bottom of an old lake. In the bottom of Lakes Superior and 

 Huron, beds of clay and sand, containing shells of recent species, 

 are being formed, t 



WALLS OF THE VALLEY. 



The escarpment forming the walls of the valley, is composed 

 principally of Medina shales (250 feet, according to Professor Spen- 

 cer)^ These are succeeded by thin beds of the Clinton formation, 

 and the whole surmounted by the beds of the Niagara formation. 

 Sections of the escarpment near Hamilton, Ancaster and at West 

 Flamboro, are given in Logan's " Geology of Canada." || The east- 

 ern escarpment presents in many ways, an aspect considerably diff- 

 erent from the western. From Hamilton to Ancaster, this escarp- 

 ment shews a clear face of hard Niagara limestone, and Niagara 

 shales, lying upon the shale beds of the Clinton and Medina forma- 

 tions, and surmounted for the greater part of the distance, by a thick 



* These measurements were mad6 in December after a long season of heavy rains, 

 t See Lyeli.'s Principles, pages 254 and 758 ; and Dr. Bigsby Jour of Science, No 

 XXXVII, pages 262 and 263. 



§ Ancient River by Prof. Spencer : page 2. 

 II Geology of Canada, page2 313 and 325. 



