GEOLOGY OF THE CLIFFS. 107 



like the ibis, which bird indeed, except in colour, 

 it more resembles than anv I have ever seen.* 



Among the trees seen in the course of this ramble, 

 I had almost forgotten to mention one which struck 

 me more than any other from its resemblance to a 

 kind of cotton tree, used by the natives of the South 

 Sea islands in building their canoes. 



Fehruari/ 7. -^The day following we secured several 

 boat-loads of rain-water, deposited in the holes of 

 the rocks, near our temporary observatory, and were 

 the better pleased with our success, as our well- 

 digging had proved unsuccessful. 



There was something particularly striking in the 

 geological formation of the cliiFs that form the wes- 

 tern side of this bay : and which rise from 70 to 90 

 feet in height, their bases apparently resting amid 

 huge and irregular masses of the same white sand- 

 stone as that which forms the cliffs themselves, and 

 from which this massive debris, strewn in all con- 

 ceivable irregularity and confusion around, appears 

 to have been violently separated by some great in- 

 ternal convulsion. 



Some of these great masses, both of the living cliff 

 and ruined blocks beneath, are strangely pierced 

 with a vein or tube of vitreous matter, not less in 

 some instances than 18 inches in diameter. In 

 every place the spot at which this tube entered 

 the rock was indicated by a considerable extent of 

 glazed or smelted surface ; but I am not sufficiently 



* Since ascertained to be au Ibis — the Threskiornis strictipennis. 



