^. 



**- 



1 





Mt 







•^^ of tie,' 



1 





sea, 



•1 



uiues 



did 



■i on all sii 

 •'liar elilfe ake 



■^ more or fe 



ti 



1 



ktrdening into a 

 tLe f^ '-ire of 

 uuikyoK ink- 



appear on * 



• bt 'do til* 



of » ^"' J 



beeJ 



beg»^ 



ed 



;i 



r. 





:.t^*^ 



I 



I 



Ch. XLIX.] 



MR. DARWIN'S THEORY OF SUBSIDENCE. 



599 



me by Lieutenant Smith, of the Blossom, that the trees 

 came down to the beach towards the centre of the island, 



resemblin 



& 



fe) 



the openings which nsiially lead into lagoons ; but the trees 

 stand on a steep slope, and no hollow of an ancient lagoon 

 was perceived. Beechey also remarks, that the surface of 



Hender 



Q 



Charlotte'^ 



Island, one of the same group, but under water, there was 

 no lagoon, the coral having grown up everywhere to one 

 level. The probable cause of this obliteration of the central 

 basin or lagoon will be considered in the sequel. 



That the bed of the Pacific and Indian oceans, where 



mi 



Mr 



efficient 



flourish in the ocean at a greater depth than 120 feet ; and, 

 secondly, that there are spaces occupying areas of many 

 hundred thousand square miles, where all the islands consist 

 of coral, and yet none of which rise to a greater height than 

 may be accounted for by the action of the winds and waves 

 on broken and triturated coral. Were we to take for granted 

 that the floor of the ocean had remained stationary from the 

 time when the coral began to grow, we should be compelled 

 to assume that an incredible number of submarine moun- 

 tains of vast height (for the ocean is always deep, and often 



ihomable 



mountain 



risen above water. But no sooner do \ 

 subsidence than this great difficulty 



admit 



However 



may 



of particular mountain-chains, aU may 

 t one uniform level by the 



level by the gradual submer- 

 gence of the loftiest points and the additions made to the 

 calcareous cappings of the less elevated summits as they 



subsided to great depths- 



Openings into the lagoons.— In the general description of 



atolls and encircling reefs^ it was 



almost always a deep narroAV passage opening into the 

 lagoon, or into the still water between the reef and the 



men 



