THE SUCCESSION OF DEPOSITS. 31 



Land plants found in the beds holding these marine shells 

 are of species still living on the north shore of the St. 

 Lawrence, and show that there were in certain portions of 

 this period considerable land surfaces clothed with vegeta- 

 tion. The upper Leda clay is probably contemporaneous 

 with the so-called inter-glacial deposits holding plants and 

 insects discovered by Hinde on the shores of lake Ontario.* 

 On the Ottawa it contains land plants of modern Canadian 

 species, insects and feathers of birds, intermixed with 

 skeletons of Capelin (Mallotus) and shells living in the 

 gulf of St. Lawrence. 



The changes of level in the course of the deposition of 

 the Leda clays must have been very great ; fossiliferous 

 marine deposits of this age being found at a height of at 

 least 600 feet, and sea-beaches at a much greater eleva- 

 tion, while at other times there must have been large 

 land areas and even fresh-water lakes. Littoral gravels 

 and sands of this period niay also be undistinguishable, 

 except by their greater elevation, from those of the-Saxi- 

 cava sand. I have described the bones of a large whale 

 (Megaptera longimana) from gravel north of the outlet of 

 lake Ontario and 420 feet above the level of the sea, 

 which is not improbably contemporaneous with the Leda 

 clay of lower levels, and much higher than deposits near 

 lake Ontario regarded as of lacustrine origin.-)- These 



* Proceedings of Canadian Institute, 1877. Dr. Hinde in this 

 paper incorrectly states that the Leda clay belongs to the "close of the 

 glacial period," and that boulder-drift is not found above it. In 

 truth, as Admiral Bayfield, Sir Charles Lyell, and the writer have 

 shown, boulder-drift is still in progress in the gulf and river St. 

 Lawrence, though in a more limited area than in the pleistocene 

 period ; but any considerable subsidence of the land might enable it to 

 resume its former extension. 



t Canadian Naturalist, Vol. X., No. 7. 



