Mesozoic and dtinozolc Oeology and Palaeontology. iJlS 



by any currents of water sweeping over the surface, under some great 

 general cause, but that it has all been quietly and silently effected by 

 the simple agency of rain and frost, acting uninterruptedly through a 

 vast period of time. 



3d.' That a large portion of the superficial detritus of the West, even 

 in those regions where drift bowlders are met with, must have had its 

 origin in the subserial destruction of the rocks, the soluble portion or 

 them having been gradually removed by the percolating water, while 

 that which I'emains represents the insoluble residuum, the sand and 

 cla}', which was originalh' present in smaller quantities in the strata 

 thus acted on. 



Bowlders of Laurentian rocks* are found in considerable numbers 

 scattered over the high tableland of western Canada, south of Georgian 

 bay. A portion of this region attains an elevation of 1,760 feet above 

 the sea. These blocks are generally more angtilar than those from a 

 similar source found at lower levels, and are associated with man}' 

 others of local origin. 



The stratified drift is separable into two divisions in western 

 Canada, the lower of which, called the Erie clay, had been partially 

 worn away betore the deposition of the upper so as to produce un- 

 conformability. The Erie cla}' is commonly more or less calcareous, 

 and always holds bowlders in greater or less abundance. The thick- 

 ness at any one place does not exceed 200 feet, but clays belonging to 

 this division occur at various levels from 60 feet below the surface of 

 Lake Ontario to 100 feet above Lake Huron, showing differences in 

 level of about 500 feet. It occurs along the north shore of Lake Erie 

 from Long Point westward to the Detroit river, and appears to under- 

 lie the whole country between this part of the lake and the main body 

 of Lake Huron. It is found at Owen sound, and along Nottawasaga 

 river, and along the shores of Lake Ontario as far east as Brockville. 

 The upper division is called the Saugeen claj', because it is well ex- 

 posed along the Saugeen river. It consists of a thinly-bedded, brown 

 calcareous clay, generally containing but few bowlders or pebbles. 

 This division occurs also at all levels from Lake Ontario to 100 feet 

 above Lake Huron, showing differences of level almost equal to that 

 of the lower clay. 



At the oil wells, on the 13th and l4th lots of thelOtli range of Ennis- 

 killen, two beds of gravel, of four and five feet respectively, have been 

 met with in the clay, at depths of ten and forty-four feet from the sur- 



* Geo. Sur. of Canada, 1863 



