Of the Vicinity of Montreal. 411 



These facts, to whicli many others might probably be added, 

 from the Reports of the Geological Survey and other sources, 

 rudely mark out parts of the shores of a larger and older gulf 

 probably contemporaneous with the newer portion of the Leda 

 clay of the lower plateau. In this condition of the St. Lawrence 

 Valley, it would still be a land locked gulf, and while we might 

 expect shore ice and breakers to mix many boulders with the gravel 

 at its margin, only a few large stones would be dropped into the 

 clay in its deeper parts by drifted ice cakes. The Leda clay, for 

 this reason, contains few boulders. 



There are, however, still higher terraces on the mountain: and 

 one of these 470 feet above Lake St. Peter, contains shells, and 

 is the highest fossiliferous deposit of this period known in Canada, 

 This beach is best seen on the property of D. Davidson, Esq.,. 

 above Cote des Neiges. It has been well described by Sir C. 

 Lyell, who recognized at once its littoral character. An excava- 

 tion kindly made for me by the proprietor, shows the following 

 succession, in descending order : 



1. Angular stones and sand 8 feet. 



2. Fine gravel, with inclined layers of shells, principally Saxicava 



regosa, 5| feet. 



3. Stratified Sand, few shells, 6 feet. 



These beds are of very limited breadth, and rest against the 

 steep side of the mountain, fronting the mouth of the Ottawa. 

 They are evidently the remains of a beach thrown up at the 

 mouth of a little cove or perhaps strait, intervening between the 

 greater and lesser summits of the mountain, which must then 

 have been rocky islets of very small size. 



The sea that washed up this beach may have reached the 

 escarpment of Niagara, and communicated with the ocean over 

 the whole of the lower lands of Lower Canada and New England. 

 It was, however, limited on the North by the high lands extend- 

 ing along that side of the St. Lawrence Valley ; and on the 

 Ottawa, *in the 4th concession of Nepean, Sir W. E. Logan has 

 observed a similar beach at a height of 410 feet. On the west, 

 the highest terrace observed by the TJ. S. Geologists on the south 

 side of Lake Ontario, appears to correspond with this sea level ; 

 and the gravel and sands containing elephantine remains near 

 Hamilton, may have been washed into its western extremity from 

 the neighbouring land. It does not appear, however, that marine 

 shells have yet been found west of Kingston. 



