344 On Areas of Subsidence In the Pacific. 



was either more rapid or carried on for a longer period in the 

 former region than in the latter, where they are nmnerous and 

 large ? 



Near the boundary line pointed out, stand some of these 

 coral rings, enclosing mountain tops as islets, — as at the Gam- 

 bier group. Does not this indicate, that the subsidence was 

 less here than among the islands purely coral to the north ? 

 And greater, than south of the line, where the reefs are more 

 contracted, and the high islands larger and more elevated \ 

 Washington Island (coral), in lat. 5° N., is the last spot of land 

 as we recede from our boundary line to the north-east. Be- 

 yond is a bare sea, to the Sandwich Islands. Is not this an 

 area where the subsidence was too rapid for the corals to keep 

 the islands at the surface ? 



It appears that, during this era, the Pacific from 30" N. to 

 80° S., and perhaps beyond, was one vast region of subsidence : 

 that subsidence took place most rapidly over the bare area 

 between the Sandwich Islands and the Equator, and less and 

 less so, as we go from this to the south-south-west. At the 

 boundary line pointed out, it was not sufficient to submerge 

 many of the mountain summits ; and south of this, the effect 

 was still less. 



This area covers at least 5000 miles in longitude, and 3000 

 in latitude. The seas about the north-west coast of New Hol- 

 land, shew by their reefs a contemporaneous subsidence, and 

 they should probably be included, as well as some parts of the 

 East Indies. Fifteen millions of square miles is not, then, an 

 over-estimate of the extent of the region that participated in 

 this subsidence. 



The region of greatest subsidence lies nearly in a west-north- 

 west line, for we may trace it along by Washington Island, far 

 towards the Arctic Coast. The whole broad area of subsidence 

 has nearly the same direction ; for this is the course of the 

 boundary line we have laid down as separating the high basal- 

 tic and the low coral islands. It is highly interesting to ob- 

 serve, that the trend of the principal groups of islands in the 

 Pacific corresponds nearly with this course. The low or co- 

 ral Archipelago, the Society Islands, the Navigators, and the 

 Sandwich Islands, lie in the same general direction, nearly west- 



