252 APPENDIX. 



found with 252 feet ; there is only one entrance into it, half a 

 mile wide, and with an island in front. The submerged banks 

 on the eastern -coast, within the same latitudes, round Far sail 

 Island, are, likewise, penetrated by many narrow creeks of deep 

 water ; one is twelve miles long, in the form of a hatchet, and 

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

 feet ; 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 surrounding banks. The 

 bottom of the sea round the Dhalac and Farsan Islands con- 

 sists chiefly of sand and agglutinated fragments of coral, but, 

 in the deep and narrow creeks, it consists of mud ; the islands 

 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 Ruppell 2 of the manner in 

 which Dhalac is 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 this irregular form, as well 

 as that of Farsan, may have been partly caused by unequal 

 elevation ; 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 currents having drifted sediment over an uneven bot- 

 tom. It is almost certain that their form cannot be attributed 

 to the growth of coral. The greater number of banks on the 

 eastern side of the Eed Sea seems to have originated in nearly 

 the same manner, whatever this may have been, as the 

 Dhalac and Farsan archipelagoes. I judge of this from their 

 similar configuration (in proof of which I may instance a 

 bank on the east coast in lat. 22°) and from their similar com- 

 position. The depth, however, within the banks northward of 



1 Eiippell, Reise in Abyssinie, band i. s. 247. 2 Ibid. s. 245. 





