W. A. E. Ussher — Historical Geology of Cornwall. 27 



compelled to give up all hope of succeeding, and returned to the 

 beach. Further evidence of the hurricane was there afforded by 

 numerous fragments of a wreck which had been thrown up on the 

 sand. Subsequently this storm was identified with one which took 

 place on the 26th of October, 1872, and did much damage in the 

 Cocos Islands and other parts of the Bay. 



The only rock seen where we landed was a conglomerate, or 

 boulder-bed, some 50 feet thick. The boulders consisted of a trachytic 

 porphyry which contained sanidine, augite, and mica, in grey or 

 pinkish matrices. We discovered no evidence whatever of recent 

 lava or basalt occurring, though either or both may exist, as our 

 observations were confined to one small bay. There is no historical 

 record, so far as I am aware, of smoke ever having been observed to 

 issue from Narkondam. It has, therefore, long been dormant, if not 

 absolutely extinct. 



Notwithstanding the luxuriance of the jungle, which included 

 species of Ficus, Palms (Caryota), Acacia, Calosanthes, etc., no fresh 

 water was discovered. 



Much remains to be done in the exploration of this most interest- 

 ing volcanic island. It is particularly desirable to ascertain whether 

 there is really a crater at the summit, and whether there are any 

 traces of recent lavas. 



Future visitors would do well to provide themselves with some 

 wood-cutters. They should land near the northern spur, and getting 

 then on the steady rise, they will probably find no insuperable 

 obstacle on their way up. 



Owing to the fact of the physical geology of the Andaman and 

 Nicobar Islands being, as yet, imperfectly known, I have not here 

 discussed the connexion which in all probability exists between their 

 elevation and this adjacent line of volcanic activity. 



III. — Historical Geologt of Cornwall. 1 

 By W. A. E. TJssher, F.G.S. 



TO ascertain the most recent movement to which a country has 

 been subjected, and by careful comparison with the past to 

 discover what insensible changes are now progressing, is of the 

 utmost importance in approaching its Quaternary History. 



By a recourse to such occasional observations as have been re- 

 corded by historians or monkish chroniclers, gleaned perhaps in 

 few cases from actual investigation, and exaggerated, no doubt, 

 in an age delighting in the marvellous, some information may be 

 gained ; but when we consider that these notes were made rather 

 for the gratification of the curious than with a view to ascertain 

 their causes or to forecast their effects, and that the facts of one 

 century may become the legends of the next, it behoves us to 

 sift the evidence, retaining only such bare and unvarnished state- 

 ments as by incidental mention and simple relation appear most 



1 The Chart to accompany this paper, of the soundings around the coast of 

 Cornwall, not being executed in time, will appear in next month's number with 

 the concluding historical part of this article. — Edit. Geol. Mag. 



