APPENDIX, 247 



penetrated by many narrow creeks of deep water; one is 

 twelve miles long, in the form of a hatchet, in which, close 

 to its broad upper end, soundings were not struck with 360 

 feet, and its entrance is only half a mile wide: in another 

 creek of the same nature, but even with a more irregular 

 outline, there was no bottom with 480 feet. The island of 

 Farsan, itself, has as singular a form as any of its surround- 

 ing banks. The bottom of the sea round the Dhalac and 

 Farsan Islands consists chiefly of sand and agglutinated 

 fragments, but, in the deep and narrow creeks, it consists of 

 mud; the islands themselves consist of thin, horizontally 

 stratified, modern tertiary beds, containing but little broken 

 coral, 1 their shores are fringed by living coral-reefs. 



From the account given by Riippell 2 of the manner in 

 which Dhalac has been rent by fissures, the opposite sides 

 of which have been unequally elevated (in one instance to 

 the amount of 50 feet), it seems probable that its irregular 

 form, as well as probably that of Farsan, may have been 

 partly caused by unequal elevations ; but, considering the 

 general form of the banks, and of the deep-water creeks, 

 together with the composition of the land, I think their 

 configuration is more probably due in great part to strong 

 currents having drifted sediment over an uneven bottom : 

 it is almost certain that their form cannot be attributed to 

 the growth of coral. Whatever may have been the precise 

 origin of the Dhalac and Farsan Archipelagoes, the greater 

 number of the banks on the eastern side of the Red Sea 

 seem to have originated through nearly similar means. I 

 judge of this from their similarity in configuration (in proof 

 of which I may instance a bank on the east coast in lat. 22 ; 

 and although it is true that the northern banks generally 



1 Riippell, Reise in Abyssinien, Band, i., s. 247. 2 Ibid., s. 245, 



