306 GOSSIP THE AFFINITY OF RACES. 



Dana observes, — "The Coral Islands of the Pacific are proofs 

 of a great secular subsidence of that Ocean. The line CCC (Phy- 

 siographic Chart) between Pitcairn's Island and the Pelews, 

 divides coral islands from those not coral ; over the area north of it 

 to the Hawaian Islands all the islands are atolls, excepting the 

 Marquesas and three or four of the Carolines. If then the atolls are 

 registers of subsidence, a vast area has partaken of it, measuring 

 6000 miles in length (a fourth of the earth's circumference) and 

 1000 to 2000 in breadth. Just south of the line there are extensive 

 coral reefs ; north of it the atolls are large, but thej diminish 

 tovrards the equator, and disappear mostly north of it ; and as the 

 smaller atolls indicate the greater amount of subsidence, and the 

 absence of islands still more, the line A A may be regarded as the 

 axial line of the great Pacific disturbance. The amount of the sub- 

 sidence may be inferred from the soundings near some of the is- 

 lands to be at least 3000 feet. But as 200 islands have disappeared, 

 and it is probable that some among them were at least as high as 

 the average of existing high islands, the whole subsidence cannot be 

 less than 6000 feet. It is probable that this sinking began in the 

 Post-tertiary period. Since this subsidence ceased, for the wooded 

 condition of the islands is proof of its having ceased, there have been 

 several cases of isolated elevations."* 



Although there is much less evidence extant of connecting links 

 by the Atlantic between the two hemispheres, than by the Pacific, 

 notwithstanding that the latter is the more expansive ocean, it is 

 probable that a continuous land, or a chain of islands stretched 

 from the Canaries to the Antilles in the remote past, where there is 

 now a wide extent of ocean. The Canaries and the Cape de Verds 

 lie in the same parellels with the West Indies and with the Pacific 

 Islands. Hypotheses and tradition must here be largely drawn 

 upon to supply the place of positive proof. The geological facts 

 presume that the West India Islands are the high lands of a sub- 

 merged continent. If so the subsidence must have been immense 

 that once took place over this wide tract of ocean ; but there is also 

 evidence of compensating elevations even in the vicinity of the line 



• See Dana's Geology, p. 587. 



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