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XXX. — Sketch of the Geology of Aden, on the Coast of Arabia. 



By FREDERICK BURR, Esq. 

 Communicated by JOHN TAYLOR, Esq., Treas. G.S. 



[Read .lanuary 6, 1841.] 



Xt is not I believe generally known to English geologists, that we have now within 

 the limits of the British dominions perhaps the finest example in the world of ex- 

 tinct volcanic action — I allude to Aden, our new settlement on the coast of Arabia, 

 where I had an opportunity of spending a short time in the early part of the 

 present year. Imperfect as the following description, the result of hasty examina- 

 tion, may be, it will still embrace a few principal facts respecting this interesting 

 locality, and serve at the same time to direct towards it the attention it so well 

 deserves. 



North. 



The promontory of Aden is situated about eighty miles eastward of the Straits 

 of Bab-el-Mandel, in latitude 13° north ; and it consists of a bold cluster of volcanic 

 rocks rising into lofty and jagged peaks, which are connected with the main land of 

 Arabia by a low sandy isthmus. The extreme length of the promontory may be 

 about six miles, the breadth half as much. The loftiest and most prominent por- 

 tions of the whole mass are volcanic, and the lower portions are partly volcanic also, 

 but exhibit many beds of consolidated sea-sand, which have been more or less ele- 



