ghalef.J 228 [March 2, 



shore must have been quite powerful. It has been clearly shown 

 by Professor Agassiz that the Florida coral reefs are but the last 

 stages in the building of that great natural breakwater, and that the 

 whole peninsula is probably the product of the work of the existing 

 species of polyps and acaleplis, working during the last geological 

 period. If this be so, then it follows that before the erection of the 

 Florida mole the Gulf Stream must have swept against the shore of 

 the Carolinas in a more direct way than it does at present. The 

 removal of the southern half of Florida would certainly increase the 

 violence with which the stream presses against the Carolina shore. 

 There is, furthermore, no doubt that the region swept by the inner 

 edge of the Gulf Stream is composed of materials calculated to wear 

 very rapidly when submitted to the action of a current of water. Al- 

 though these considerations are not calculated to give us any decided 

 assurance concerning the part which the Gulf Stream has played in 

 the erosion of this shore, they still make it probable that it has had 

 no unimportant share in the shaping of the coast. 



It may be remarked, in passing, that there seems to be no clear 

 evidence of recent subsidence on this coast. I am satisfied that the 

 many facts which seem to indicate such action, and which have even 

 deceived the remarkably acute Sir Charles Lyell, are really to be 

 attributed to a variety of minor accidents, such as the undermining 

 of the coast by the action of the waves, or to the rotting away of a 

 considerable thickness of vegetable matter beneath the surface of 

 the ground. This view of the meaning of these supposed evidences 

 of subsidence is ably defended by Professor Tuomey in his report on 

 the Geology of South Carolina. 1 



The Geology of the Phosphate Beds. 



The effort to identify accurately the formations of North America 

 with those of Europe has led in some cases to the hasty use of the 

 names which have been applied to certain beds in the European sec- 

 tions, to designate American rocks. 



In the nomenclature of the South Carolina beds, we have what 



1 Dr. Ravenel thinks that he has recognized the phosphate beds at the depth of 

 about sixty feet below the surface, at Charleston. If this should be verified, we 

 would be compelled, as will be seen hereafter, to suppose that after the formation 

 of the phosphate bed under atmospheric agencies, the shore had been depressed 

 to the depth of at least sixty feet below its present position. It would be difficult 

 to account for such a great subsidence at this point, while beds at a distance of 

 nine miles to the westward have not changed their position. 



