34 I oicanoes in the Buy of Bengal '. 



The minerals found at Aden are very numerous. We have 

 almost every variety of lava, compact, earthy, vesicular, 

 amygdaloidal, and porphyritic ; obsidian in all its forms, 

 from dull coarse green and blush green to beautiful jet 

 black. Pumice is found, but it is not plentiful. It is mostly 

 of a dark reddish-brown colour, and is heavier and more 

 coarse in its texture than the mineral of commerce, and less 

 suited for the finer purposes of the polisher. Sulphur is 

 sometimes found, but rarely. Rock crystals in veins next, 

 and crusts are very plentiful everywhere. On many parts of 

 the volcano chalcedony in various forms abounds ; in some 

 cases it appears in thin crusts, in button-shaped encrusta- 

 tions, or in drops or studs, occasionally covered over with 

 delicate rock crystals. They are of a beautiful bluish-white, 

 and take a prominent place in any cabinet. On these are 

 occasionally found small crystals of purple fluor-spar, from 

 the size of a mustard seed to that of a small pea. Carbonate 

 of lime appears as calcareous spar, frequently filling veins and 

 cavities of a slightly-crystallized veined variety of marble, 

 of various tints of brown, exactly like the Gozo marble seen 

 at Malta, and the portions of the rock of Gibraltar from 

 which ornaments are mostly cut. Sulphate of lime is found 

 in veins in the form of beautiful fibrous gypsum, semi-trans- 

 parent, and colourless. It also occurs in plates. Specimens 

 of all the minerals here described I have in abundance in 

 my own cabinet. They have been mostly collected for me 

 by Dr Malcolmson, Mr Moyes, and Mr Adie ; the duration 

 of my own visits to Aden precluding me from procuring the 

 rare minerals. 



Right across the bay to the westward, at a distance of 

 five miles, are the magnificent remains of another crater, 

 called Gibbel Hasson. It is nearly of the same size and form 

 as Aden, but rests on the mainland. The centre peak at- 

 tains an altitude of 1237 feet, and on sailing round it from 

 Aden, it, in certain aspects, presents the appearance of a 

 stupendous Gothic cathedral. Two peaks of 700 feet, close 

 beside each other, have obtained the very unpicturesque 

 name of " The Asses' Ears," from the appearance presented 

 by them far out at sea ; while 7 miles beyond this, and 17 



