WEST INDIES. 255 



we have seen, may be due simply to the growth of corals on 

 an irregular abraded foundation. But between lat. 18° and 

 20° there are so many linear, elliptic and extremely small 

 reefs, rising abruptly out of profound depths, that the same 

 reasons which led me to colour a portion of the west coast 

 blue, have induced me here to do the same. There are some 

 small outlying reefs on the east coast, north of lat. 20° (the 

 northern limit coloured blue), which rise from deep water ; 

 but as they are not numerous, and as scarcely any of them 

 are linear, I have left them uncoloured. 



In the southern parts of the Eed Sea, considerable spaces 

 o£ the main land, and some of the Dhalac islands, are skirted 

 by reefs, which, as I am informed by Captain Moresby, are of 

 living coral, and have all the characters of the fringing class. 

 As there are here no outlying linear or sickle-formed reefs, 

 rising out of unfathomable depths, I have coloured these parts 

 of the coast red. On similar grounds I have coloured the 

 northern parts of the western coast (north of lat. 24° 30') 

 red, and likewise the shores of the chief part of the Gulf of 

 Suez. In the Gulf of Acaba, as I am informed by Captain 

 Moresby, there are no coral-reefs, and the water is profoundly 

 deep. 



West Indies. — My information regarding the reefs of this 

 area is derived from various sources, and from an examina- 

 tion of numerous charts ; especially of those lately executed 

 during the survey under Captain Owen, E.N. I lie under par- 

 ticular obligation to Captain Bird Allen, R.N., one of the mem- 

 bers of the late survey, for many personal communications on 

 this subject. As in the case of the Red Sea, it is necessary to 

 make some preliminary remarks on the submerged banks of 

 the West Indies, which are in some degree connected with 

 coral-reefs, and cause considerable doubts in their classification. 

 That large accumulations of sediment are in progress on the 

 West Indian shores, will be evident to any one who examines 

 the charts of that sea, especially of the portion north of a line 



