On the Secondary and Tertiary Formations. 339 



cemented together by a ferruginous cement, forming a solid 

 ledge on the edges of the water. This is the farthest point 

 to the south where I observed this deposit ; but I was told it oc- 

 curs again on the Waccamaw river. 



In treating of the tertiary formations of our country, I have 

 preferred using the conventional names adopted by Mr. Conrad, 

 of upper, medial, and lower tertiary, to those of pliocene, mio- 

 cene, and eocene, applied to similar formations in Europe. The 

 former merely indicate relative position, and are therefore suffi- 

 cient at present ; the latter imply a relative proportion, of course 

 not very exact, of extinct and recent shells ; and though our own 

 formations may now each give about the same proportion with 

 the English formations, still when two hours' work may discover 

 more than twenty undescribed species in one locality, besides some 

 recent species not before noticed in the formation ; and when our 

 knowledge of the living shells of our coast is so imperfect, it 

 certainly proves that the adoption of these new names would 

 now be hasty. It would be at once taking it for granted, (as it 

 is certainly not proved,) that our strata will be readily divisible 

 into the same three formations as those of Europe ; and all diffi- 

 culties, if any are hereafter encountered, will be too apt to be 

 made to bend, or to be neglected, for the sake of keeping to this 

 favorite but unproved system of classification. This subject, I 

 hope, will be more fully discussed by Mr. Conrad, and sustained 

 by more complete details than I am able to furnish. 



At the locality last mentioned, near the boundary line, are 

 found through the fields singular deposits of oyster shells, each 

 extending over several feet square and about two feet deep. No 

 account is preserved of the time or cause of these collections. 

 They were made centuries ago, probably by the Indians. Corn 

 does not grow well by these heaps, at which I was rather sur- 

 prised. 



There is a well known locality of the secondary limestone at 

 the Eutaw Springs, near Nelson's ferry over the Santee, in the 

 western part of Charleston district. The striking similarity of 

 this rock to that in Jones county, N. C. first attracted my atten- 

 tion. Like it the limestone rose above the surface in heavy rag- 

 ged ledges, here at least fifteen feet high ; it was of the same 

 light yellow color, and contained similar fossil shells. Similar 

 springs too rise among the ledges of the rock, and they contain 



