68 , FEANK D. ADAMS ON THE 



by the sandstones, etc., of the " Waverly Group," which marks the base of the Carbonifeï- 

 ous, and which in its turn is overlaid by the carboniferous limestone and coal measures 

 occupying the central portion of the state. 



The distribution of these formations is shown in the accompanying geological map. 

 The entire area, however, both in Ontario and Michigan is heavily drifted, so that over 

 long stretches of country no outcrop can be seen. 



This drift in Ontario has not been as yet carefully studied. In the early years of the 

 Canadian Oeological survey it was examined iu a general way, and in the ' G-eology of 

 Canada,' published in 1863, was classified as follows, in descending order : — 



Recent Alluvia. 



Artemesia Gravel and Algoraa Sand. 



Saugeen Clay and Sand. 



Erie Clay. 



Boulder Clay. 



There is reason to believe, however, that the Saugeen clay and, perhaps, some of the 

 other members of the series are secondary deposits whose material was derived from the 

 underlying boulder clay. 



The following extract from a report prepared by Dr. Bell, of the Canadian Geological 

 survey, for the Royal Commission on the Mineral Resources of Ontario, gives a general 

 description of the Saugeen and Erie clays : — 



" West of the points above mentioned, south of the height of the land, the marine 

 deposits are replaced by others which appear to be in part, at least, of fresh water origin. 

 One of the most important of these is an extensive blue clay deposit which we have called 

 the Erie clay, and which has as yet yielded no organic remains of any kind. It burns to 

 white bricks, while the marine clays to the east burn red. The Erie clay is often very 

 calcareous, and is seldom or never entirely free from pebbles and stones, more or less 

 thickly disseminated through it. Indeed, it often seems to merge into the underlying 

 boulder clay. It covers the whole of the southwestern part of the western peninsula, 

 and is locally developed in many other parts of the province, as far east as the line of rail- 

 way from Brockville to Ottawa. Its greatest known depth is about 200 fet^t, but it is 

 found at differences of levels amounting to 500 feet. When seen iu fresh sections it pre- 

 sents lines of stratification, and often a transversely jointed structure. In some localities 

 its upper parts have been unevenly denuded before the deposition of the next higher 

 formation, which consists of brownish clay yielding red bricks. This unconformable 

 formation is well developed in the valley of the Saugeen River, and hence it has received 

 the name of the Saugeen clay. Its thickness appears to be less than that of the Erie clay, 

 but it is found in broken areas iu all parts of the province, except the most easterly and 

 northerly. When seen in fresh sections it is usually found to be very distinctly stratified 

 in thin layers ; sometimes with partings of fine sand between them. Beds of sand and 

 gravel are occasionally found between the Erie and Saugeen clays, and these are of im- 

 portance as aflbrding good wells of water. Fresh water shells have been detected in a 

 few instances in the Saugeen clay." 



The "marine clays " above mentioned are those found in the valley of the St. Law- 

 rence east of Brockville and known as the Leda clays, being probably the eastern equiva- 



