252 APPENDIX. 



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

 foundly deep. 



West Indies. — My information regarding the reefs of 

 this area, is derived from various sources, and from an 

 examination of numerous charts ; especially of those lately 

 executed during the survey under Capt. Owen, R.N. I lay 

 under particular obligation to Capt. Bird Allen, R.N., one 

 of the members of the late survey, for many personal com- 

 munications 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 joining Yucutan 

 and Florida. The area of deposition seems less intimately 

 connected with the debouchement of the great rivers, than 

 with the course of the sea-currents ; as is evident from the 

 vast extension of the banks from the promontories of 

 Yucutan and Mosquito. 



Besides the coast-banks, there are many of various dimen- 

 sions which stand quite isolated ; these closely resemble 

 each other ; they lie from 2 or 3 to 20 or 30 fathoms 

 under water, and are composed of sand, sometimes firmly 

 agglutinated, with little or no coral; their surfaces are 

 smooth and nearly level, shelving only to the amount of a 

 few fathoms, very gradually all round towards their edges, 

 where they plunge abruptly into the unfathomable sea. 

 This steep inclination of their sides, which is likewise 

 characteristic of the coast-banks, is very remarkable : I may 

 give as an instance, the Misteriosa Bank, on the edges of 

 which the soundings change in 250 fathoms horizontal 



