July 29. 1897] 



NATURE 



301 



SOME PROBLEMS OF ARCTIC GEOLOGY. 



I. The Polar Basin.^ 



T TNTIL the return of the Fra/n from its epoch-making drift, 

 ^ the belief was ahnost universal "^ that the Arctic Ocean is a 

 shallow, island-strewn sea ; and the evidence for this view 

 was thought to be so conclusive, that theories of Arctic geology 

 might be safely based upon the hypothesis. Facts inconsistent 

 with the theory were not unknown. Scoresby had let out two 

 miles of line west of Spitsbergen, and Parry had sounded with a 

 500-fathom line at his furthest north, and on neither occasion 

 was the bottom reached; Nordenskjold, in the Sofia, had found 

 that the sea at 8l° 32' N. and i7°3o'E. was 1300 fathoms deep. 

 But this direct evidence did not shake the widespread belief in 

 the general shallowness of the areas where no direct evidence 

 was available. This theory was originally based on the notion 

 that ice cannot be formed on the sea except where it is shallow ; 



HI Camozoic 



l:---i Mesozoic 



WSk Devonian & Carbomkrous\ oF 



WM Silurian jyUiierica, 



^^a Paleozoic of Furasia 



lt-t-l| Ardiean & ? Camirian , 



Yolcenic Rocks omitted 



Fig. 



-Geological Sketch Map of Polar Regions. 



ind after this view was proved to be mistaken, the old conclu- 

 sion was maintained by various authorities from many different 

 considerations. Thus Petermann, the great German Arctic 

 geographer, deduced the extension of (}reenland across the Pole 

 to Wrangel Land near Behring Straits, from the distribution of 

 drift-wood. It is well known that the Siberian rivers carry 

 down vast quantities of tree-trunks, which float across the Arctic 

 Ocean, and are cast upon its shores. But there is very little of 

 this drift-wood in the Robeson Channel, and at the northern 

 end of Smith's Sound. Petermann, therefore, concluded that 

 there caq be no direct sea communication between that strait 

 and the coast of Northern Asia. While Petermann inferred the 

 existence of a land connection between Greenland and the 



1 As limits of space prevented the insertion of adequate references to 

 authorities, it has been thought advisable to omit them altogether. 



2 The principal opponent of this view was Dr. J. Murray. 



Asiatic islands from the discontinuity of the sea. Sir Allen 

 Young, even as late as 1893, held that there is direct evidence 

 of its actual existence ; for the Governor of Upernivik, the most 

 northern Danish settlement in Greenland, received from a 

 native hunter a reindeer skin which had been branded with one 

 of the marks used in Siberia; hence Young argued that this 

 reindeer must have walked across from Siberia, which it could 

 only have done along a line of continuous land, or, at least, a 

 chain of i.<;lands. The existence of land to the north of Green- 

 land was also maintained by Captain Tyson, the chronicler of the 

 Hall Expedition, owing to the very moderate current that flows 

 southward down Robeson Channel, which, it was said, could 

 only be explained by the assumption that a northern archipelago 

 acted as a weir. Again, Admiral Sherard Osborn contended 

 that the sea to the north of the Parry Islands is a land-locked 

 basin, as its characteristic icebergs never pass out through either 

 Smith Sound or along the eastern coast of Greenland ; and the 

 occurrence of land to the north of Spitsbergen 

 was asserted, as flocks of birds fly northward 

 as if on their way to a safer breeding- place. 



How firmly ingrained this view of the 

 shallowness of the Arctic Ocean had grown, 

 cannot perhaps be more strikingly illustrated 

 than by the fact that the Fram was only 

 supplied with apparatus for sounding in 

 comparatively slight depths. Accordingly, 

 geologists and biologists were permitted to 

 introduce great changes in the size and position 

 of the Arctic Ocean without any objections 

 being raised. Thus Sir J. D. Hooker was 

 allowed to call up great land areas from the 

 Arctic deeps, to account for the apparent 

 eccentricities of plant distribution. When Sir 

 Chas. Lyell explained the vicissitudes of Arctic 

 climates by a different arrangement of land and 

 water in the North Polar regions, no h priori 

 protests were made. But the sounding-line of 

 the Fram has changed all that, for it has intro- 

 duced into Arctic geology the theory of the 

 permanence of oceanic basins. If that theory 

 be true, then throughout the ^ons of geological 

 time a large part of the Polar area has been 

 occupied by a vast, deep reservoir of water. 

 In that case many of the problems of British 

 geology require solutions, different from those 

 which have hitherto been deemed satisfactory. 

 The question whether the Polar Basin has 

 been permanent, and, if not, at what age it 

 has been formed, is the problem of greatest 

 geological importance raised by the voyage 

 of the Fram. 



In the case of the other oceans, biological 

 evidence is fortunately available. Thus a map 

 of the world marked off into botanical regions, 

 shows that in the tropics and the southern 

 hemisphere the ocean basins separate distinct 

 floras. Thus South America, Africa, and 

 Australia now belong to different botanical 

 regions, so that these three continents must 

 have been separated from one another for a 

 very long period. But palteo-botanical evi- 

 dence shows that in Triassic times they were 

 inhabited by the same flora ; and therefore, 

 during or immediately preceding that period, 

 they were not so completely separated by ocean barriers as 

 they are to-day. But in the case of the Arctic Ocean we 

 get no such assistance from biological evidence, for one 

 flora and one fauna extend uninterruptedly through all the 

 Arctic lands. This uniformity may have resulted from the 

 original development of this flora and fauna in some land around 

 the Pole, whence they spread radially into Europe, Asia and 

 America. But, on the other hand, it may have resulted from 

 an east or west diffusion along the circum-arctic belt of land. 

 That this land has not always been arranged as it is at present, 

 ! is rendered almost certain by the minor differences that occur in 

 ' the floras of different parts of the Arctic zone. For example, 

 I the line of separation between the American and European sub- 

 I divisions of the Boreal botanical realm does not run between 

 I Greenland and Iceland, but between Greenland and the rest of 

 1 the American archipelago. In fact, according to Hooker and 



NO, 1448, VOL. 56] 



