BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 12, pp. 129-146 March 25, 1901 



MARINE AND FRESHWATER BEACHES OF ONTARIO 



• BY A. P. COLEMAN 



{Read before the Society December 28^ 1900) 

 CONTENTS 



Page 



Marine deposits 129 



Shell-bearing gravels 132 



Old water-levels to tlfe west 1.34 



Climate, and age of the marine beds 13(5 



High-level beaches in southern Ontario 138 



Beaches farther north 139 



Conclusions 143 



Marine Deposits 



The Pleistocene marine beds of Ontario have been studied for many 

 years and have yielded a great number of fossils at different points along 

 the Saint Lawrence and Ottawa and in the country between these two 

 rivers, as well as along the rivers flowing north into Hudson bay,* prov- 

 ing that the sea once occupied these regions for a length of time sufficient 

 to form beds of clay and sand often more than 100 feet thick. Sir William 

 Dawson has divided these deposits into "Leda clay "and "Saxicavasand," 

 the names being derived from the commonest fossils occurring in them. 

 The Leda clay usually rests on boulder-clay, and the Saxicava sand 

 usually overlies the Leda clay, so that in general one may say that the 

 stratified marine beds were formed later than the last retreat of the ice 

 from the region mentioned. 



Probably the beds most productive in fossils of any of these deposits 

 in Ontario are those in and about Ottawa, and these may be described as 

 typical. The Leda clay is well disclosed in the city itself, and at Greens 



*Geol. Can., 1863, pp. 915-928; Can. Ice Age, Sir Wm. Dawson, pp. 203, etcetera; Reports of Dr 

 Bell in the Geol. Survey Can., 1871-'72, p. 112 ; also 1875-'7G, p. 340. Dr Ami also has collected many 

 species, some of which are enumerated in the Ottawa Naturalist, vol. xi. no. 1, pp. 20-2G. 



XIX— Bum,. Geoi,. Soc. Am., Vol. 12, 1900 (129) 



