3i6 CORALS AND CORAL LS LANDS. 



have been bending downward over the vast central area of the 

 great ocean. 



The changes which took place, cotemporaneously, in the 

 Atlantic tropics are very imperfectly recorded. The Bahamas 

 show by their form and position that tliey cover a submerged 

 land of large area stretching over six hundred miles from 

 north-vvest to south-east. The long line of reefs and the 

 Florida Keys, trending far away from the land of southern 

 Florida, are evidence that this Florida region participated in 

 the downward movement, though to a less extent than the 

 Bahamas. Again, the islands of the West Indies diminish in 

 size to the eastward, being quite small, in a long line that looks 

 out upon the blank ocean, just as if the subsidence increased 

 in that direction. Finally, the Atlantic beyond is water 

 only, as if it had been made a blank by the sinking of its 

 lands. 



Thus the size of the islands, as well as the existence of 

 coral banks, and also the blankness of the ocean's surface, all 

 appear to bear evidence to a great subsidence. 



The peninsula of Florida, Cuba, and the Bahamas look, as 

 they lie together, as if all were once part of a greater Florida 

 or south-eastern prolongation of the continent. The north- 

 western and south-western trends, characterizing the great 

 features of the American continent, run through the whole 

 like a warp-and-woof structure, binding them together in one 

 system ; the former trend, the north-west, existing in Florida 

 and the Bahamas, and the main line of Cuba; and the latter 

 course, the west-southwest, in cross lines of islands in the 

 Bahamas (one at the north extremity, another in the line of 

 Nassau, and others to the south-east), in the high lands of 

 north-western and south-eastern Cuba, and in the Florida Hne 

 of reefs, and even farther, in a submerged ridge between 

 Florida and Cuba. This combination of the two continental 

 trends shows that the lands are one in system, if they were 

 never one in continuous dry land. 



We cannot here infer that there was a regular increase of 

 subsidence from Florida eastward, or that Florida and Cuba 



