ADDRESS. 29 



southern limit of the sabsidence, or of the line along which the cold 

 currents bearing ice were abruptly cut off by warm surface waters. I 

 am glad to find that these considerations are beginning to have weight 

 "with European geologists in their explanation of the glacial drift of the 

 great plains of Northern Europe. 



Whatever difficulties may attend such a supposition, they are small 

 compared with those attendant on the belief of a continental glacier, 

 moving without the aid of gravity, and depending for its material on the 

 precipitation taking place on the interior plains of a great continent. 



I have elsewhere endeavoured to show, on the evidence found in Canada, 

 that the occurrence of marine shells, land plants, and insects in the glacial 

 deposits of that country indicates not so much the effect of general 

 interglacial periods as the local existence of conditions like those of 

 Grinnel-land and Greenland, in proximity to each other at one and the 

 same period, and depending on the relative levels of land and the distribu- 

 tion of ocean currents and ice drift. ^ 



I am old enough to remember the sensation caused by the delightful 

 revelations of Edward Forbes respecting the zones of animal life in the 

 sea, and the vast insight which they gave into the significance of the 

 work on minute organisms previously done by Ehrenberg, Lonsdale, and 

 Williamson, and into the meaning of fossil remains. A little later the 

 soundings for the Atlantic cable revealed the chalky forcminiferal ooze of 

 the abyssal ocean ; still more recently the wealth of facts disclosed by the 

 Challenger voyage, which naturalists have not yet had time to digest, 

 have opened up to ua new worlds of deep-sea life. 



The bed of the deep Atlantic is covered for the most part by a mud 

 or ooze largely made up of the debris of foraminifera and other minute 

 organisms mixed with fine clay. In the North Atlantic the Norwegian 

 naturalists call this the Biloculina mud. Further south the Ohallenger 

 naturalists speak of it as Globigerina ooze. In point of fact it contains 

 different species of foraminiferal shells, Globigerina and Orbulina being 

 in some localities dominant, and in others other species, and these changes 

 axe more apparent in the shallower portions of the ocean. 



It is also to be observed that there are means for disseminating coarse 

 material over the ocean bed. There are in the line of the Arctic current 

 on the American coast great sand-banks, and off the coast of Norway 

 sand constitutes a considerable part of the bottom material. Soundings 

 and dredgings ofE Great Britain, and also off the American coast, have 

 shown that fragments of stone referable to Arctic lands are abundantly 

 strewn over the bottom along certain lines, and the Antarctic continent, 

 otherwise almost unknown, makes its presence felt to the dredge by the 

 abundant masses of crystalline rock drifted far from it to the north. 

 These are not altogether new discoveries. I had inferred many years ago, 



■ Notes on Pott-Pliocene of Canada, 1872. One well-marked interval only has been 

 established in the glacial deposits o£ Canada. 



