FAUNA OF NOBTH ATLANTIC 17 



the arctic flora had originated in Greenland in pre -Glacial 

 times and had been scattered east and west across the exist- 

 ing land bridges on the advent of the Glacial Epoch, during 

 which the maintenance of life was no longer possible in that 

 country. 



Sir Joseph Hooker * long ago expressed the opinion that, 

 although many Greenland plants were possibly destroyed 

 during the Ice Age, the existing remnant of a much richer 

 flora had survived in the southern parts of the country, whence 

 it subsequently spread northward again. 



One of the biological arguments I adduced in favour of a 

 former north Atlantic land bridge was derived from the well- 

 known fact that deposits of dead marine shallow-water species 

 had been dredged in deep water in various localities such as 

 Kockall Bank and off the coast of Iceland. This peculiar 

 circumstance has been applied by several authorities in sup- 

 port of the theory of a gradual sinking of the land, the 

 shallow-water species having thus been moved to a position 

 in which they are no longer able to live. It is this part of 

 the biological argument on the land bridge theory which has 

 received most of the adverse criticism. Dr. Johansen,f for 

 instance, pointed out that the evidence derived from the 

 marine shallow-water shells is untrustworthy, because their 

 presence in great depths in the northern Atlantic is not due 

 to a sinking of the land, but mainly to various casual or 

 accidental activities of transport. The theory of the north 

 Atlantic land bridge, in so far as it is founded upon the occur- 

 rence of shallow-water marine shells at great depths, does 

 not, therefore, meet with his approval. 



Similarly, Dr. Appell<f J insists that the most recent dis- 

 coveries on the " Faroe Bank " are of considerable zoogeo- 

 graphical significance, since they are opposed in some 

 measure to the theory of the sinking of the land. He informs 

 us that among the thick layer of dead shallow shells found 

 on the Faroe Bank living specimens of several of the species 

 were met with. 



* Hooker, J. D., " Distribution of Arctic Plants," pp. 252255. 

 f Johansen, A. C., "On the Sinking of Sea-beds," p. 403. 

 I Appeltyf. A., " Norwegian Fisheries," Vol. II., pp. 8389. 

 L.A. Q 



