THE HISTORY OF THE NORTH ATLANTIC 79 



summed up the known facts as to Arctic geology in a series of 

 articles in Nature, from which it appears that this area pre- 

 sents from without inwards a succession of older and newer 

 formations from the Eozoic to the Tertiary, and that its extent 

 must have been greater in former periods than at present, 

 while it must have enjoyed a comparatively warm climate from 

 the Cambrian to the Pleistocene period. The relations of its 

 deposits and fossils are closer with those of the Atlantic than 

 with those of the Pacific, as might be anticipated from its wider 

 opening into the former. Blandford has recently remarked on 

 the correspondence of the marginal deposits around the Pacific 

 and Indian oceans,^ and Dr. Dawson informs me that this is 

 equally marked in comparison with the west coast of America, 

 but these marginal areas have not yet gained much on the 

 ocean. In the North Atlantic, on the other hand, there is a 

 wide belt of comparatively modern rocks on both sides, more 

 especially toward the south and on the American side ; but 

 while there appears to be a perfect correspondence on both 

 sides of the Atlantic, and around the Pacific respectively, there 

 seems to be less parallelism between the deposits and forms of 

 life of the two oceans, as compared with each other, and less 

 correspondence in forms of life, especially in modern times. 

 Still, in the earlier geological ages, as might have been antici- 

 pated from the imperfect development of the continents, the 

 same forms of life characterise the whole ocean from Austraha 

 to Arctic America, and indicate a grand unity of Pacific and 



^ Journal of Geological Society, May, 1886, Blandford's statements re- 

 specting the mechanical deposits of the close of the Palaeozoic in the Indian 

 Ocean, whether these are glacial or not, would seem to show a correspond- 

 ence with the Permian conglomerates and earth movements of the Allan- 

 tic area ; but since that time the Atlantic has enjoyed comparative repose. 

 The Pacific seems to have reproduced the conditions of the Carboniferous 

 in the Cretaceous age, and seems to have been less affected by the great 

 changes of the Pleistocene. 



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