ANTARCTIC ADVENTURE AND RESEARCH 



rangement, whereby the lands and seas are opposed, as 

 indicated in the following table : 



Antarctica opposite Arctic Ocean 



Eur-Africa " Pacific Ocean 



America " Indian Ocean 



Australia-E. Asia " Atlantic Ocean 



The narrow southern portion of South America is 

 the only notable exception to the general rule. Hobbs ^ 

 has pointed out that if we add the drowned continental 

 margins, then the land areas are increased by ten mil- 

 lion square miles, and in some respects the antipodal 

 arrangement is emphasized. Around Antarctica the 

 continental shelf presents some special features, show- 

 ing evidence of greater drowning than usual, as we 

 shall see in a later chapter. On the other hand, the 

 Arctic Ocean is surrounded by a remarkably broad 

 and shallow series of shelf seas. It may be mentioned 

 that when a hollow glass sphere is blown by the glass- 

 maker it has a strong tendency to collapse to a per- 

 ceptible tetrahedral shape as it contracts on cooling. 

 Something of this sort may have given rise to the plan 

 of the earth. It is clear that the mobile waters of the 

 oceans would accumulate on the ''faces" of the tetra- 

 hedron, since here the gravity pull is greatest. So also 

 the projecting edges of the tetrahedron would con- 

 stitute the main land masses. This is possibly the basis 

 of the ring of lands round the Arctic Ocean, and of the 

 three south-pointing land masses of Eur-Africa, Amer- 



3W. H. Hobbs, Earth Evolution (New York, 1921). 



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