APPENDIX. 255 



is now accumulating ; for instance on the northern part 

 of Yucutan, and on the N.E. part of Mosquito, where the 

 land is low, and where extensive banks appear to be in 

 progressive formation. Hence, also, the origin of the 

 Great Bahama Banks, which are bordered on their western 

 and southern edges by very narrow, long, singularly shaped 

 islands, formed of sand, shells, and coral-rock, and some 

 of them about a hundred feet in height, is easily explained 

 by the elevation of banks fringed on their windward (western 

 and southern) sides by coral-reefs. On this view, however, 

 we must suppose either that the chief part of the surfaces 

 of the great Bahama sandbanks were all originally deeply 

 submerged, and were brought up to their present level by 

 the same elevatory action, which formed the linear islands , 

 or that during the elevation of the banks, the superficial 

 currents and swell of the waves continued wearing them 

 down and keeping them at a nearly uniform level : the 

 level is not quite uniform ; for, in proceeding from the 

 N.W. end of the Bahama group towards the S.E. end, 

 the depth of the banks increases, and the area of land 

 decreases, in a very gradual and remarkable manner. The 

 latter view, namely, that these banks have been worn down 

 by the currents and swell during their elevation, seems to 

 me the most probable one. It is, also, I believe, applicable 

 to many banks, situated in widely distant parts of the West 

 Indian Sea, which are wholly submerged ; for, on any other 

 view, we must suppose, that the elevatory forces have acted 

 with astonishing uniformity. 



The shores of the Gulf of Mexico, for the space of many 

 hundred miles, is formed by a chain of lagoons, from one 

 to twenty miles in breadth {Columbian Navigator, p. 178, 

 etc.) containing either fresh or salt water, and separated 

 from the sea by linear strips of sand. Great spaces of 



