THE TERTIARY TO THE MODERN PERIOD. 227 



In Canada, in the Pleistocene beds known as the Leda 

 clays, intervening between the lower boulder clay and 

 the Saxicava sand, which also holds boulders, there are 

 beds holding fossil plants, in some places intermixed with 

 sea-shells and bones of marine fishes, showing that they 

 were drifted into the sea at a time of submergence. 

 These remains are boreal rather than arctic in character, 

 and with the remains of drift-wood often found in the 

 boulder deposits serve to indicate that there were at all 

 times oases of hardy life in the glacial deserts, just as we 

 find these in polar lands at the present day. I condense 

 from a paper on these plants * the following facts, with a 

 few additional notes : 



The importance of all information bearing on the 

 temperature of the Post - pliocene period invests with 

 much interest the study of the land-plants preserved in 

 deposits of this age. Unfortunately, these are few in num- 

 ber, and often not well preserved. In Canada, though 

 fragments of the woody parts of plants occasionally occur 

 in the marine clays and sands, there is only one locality 

 which has afforded any considerable quantity of remains 

 of their more perishable parts. This is the well-known 

 deposit of Leda clay at Green's Creek, on the Ottawa, 

 celebrated for the perfection in which the skeletons of 

 the capelin and other fishes are preserved in the calcareous 

 nodules imbedded in the clay. In similar nodules, con- 

 tained apparently in a layer somewhat lower than that 

 holding the ichthyolites, remains of land-plants are some- 

 what abundant, and, from their association with shells of 

 Leda glacialis, seem to have been washed down from the 

 land into deep water. The circumstances would seem to 

 have been not dissimilar from those at present existing 

 in the northeast arm of Gaspe Basin, where I have dredged 

 from mud uow being deposited in deep water, living 



* "Canadian Naturalist," 1866. 



