THE HISTORY OF THE NORTH ATLANTIC 83 



The bed of the deep Atlantic is covered, for the most part, 

 by a mud or ooze, largely made up of the debris of foramini- 

 fera and other minute organisms mixed with fine clay. In the 

 North Atlantic the Norwegian naturalists call this the Biloculina 

 mud. Farther south, the Challenger 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 are more apparent in the shallower portions of the 

 ocean. 



On the other hand, there are means for disseminating 

 coarse material over parts of the ocean beds. 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 off 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, 

 from stones taken up by the hooks of fishermen on the banks 

 of Newfoundland, that rocky material from the north is dropped 

 on these banks by the heavy ice which drifts over them every 

 spring, that these are glaciated, and that after they fall to the 

 bottom sand is drifted over them with sufficient velocity to 

 polish the stones, and to erode the shelly coverings of Arctic 

 animals attached to them. 1 If, then, the Atlantic basin were 

 upheaved into land, we should see beds of sand, gravel and 

 boulders with clay flats and layers of marl and limestone. 

 According to the Challenger reports, in the Antarctic seas S. 

 of 64 there is blue mud, with fragments of rock, in depths 

 1 "Notes on Post-Pliocine of Canada," 1872. 



