2 



MALLET : ADEN AND VICINITY. 



struck the liills. From thence I returned to Aden which I reached on 

 the first of December, and sailed for Calcutta on the third. 



The country viewed with regard to water suppl}^, as indeed in an 

 Geological division of ordinary geological point of view, naturally divides 

 the country. itself into three sections, 1^^, the volcanic penin- 



sula of Aden itself, to which may be added the hills of Little Aden on the 

 opposite side of the harbour ; '^nd, the plain which stretches northward 

 to the foot' of the hills, a distance of about five and thirty miles ; and 

 thirdly, the hill ranges to the north, which are composed of stratified rocks 

 and run in an east and west direction. It wag to the second of these, 

 ' the country between the sea and the mountains near Aden^ that the 

 Government suggested that attention should be directed, and -it was to 

 this plain that I devoted most time, but it will be well to indude the 

 peninsula and the hills also in the enquiry. 



Before describing the geological structure of Aden and _ the 



country to the north, it may be convenient to 

 Geiieral condition!? re- "^ '' 



quired for Artesian wells, allude for the sake of comparison, to the general 

 conditions of stratigraphy under which artesian borings can be made 

 with success. The circumstances most favorable to such an under- 

 taking are, when a thick bed of material (b) highly porous and permeable 

 to water, such as sand or gravel, is intercalated between two beds 



Fig-, i, Sketch section slicTFing- genefal couditiouii I'avoi'able for al'tesian wells.. 



( 2.58 ) 



