Shaler.] 230 [March 2, 



and the Cooper Rivers, that there is to doubt the identity of the age 

 of the latter beds and the buhr-stone. The identity of the first 

 named beds does not seem to be sufficiently proven; the contempora- 

 neous origin of the last named is at first sight so improbable that 

 it cannot be accepted without direct proof, which has not been pre- 

 sented. The level character of a large part of the surface over 

 which these beds in question extend, makes it extremely difficult to 

 trace by natural sections the relations of these several series of rocks. 

 The palaeontological evidence not being clear, the matter must re- 

 main in some doubt until we have artificial sections which artesian 

 wells, tapping the abundant subterranean waters of this region, will 

 doubtless soon give. 



Overlying the Santee beds and the beds of the Ashley and Cooper 

 Rivers, there are found at various points marls which are probably to 

 be regarded as of a Pliocene age. This is the aire assigned to them 

 by Mr. Tuomey, and if we must make a division of the tertiary sec- 

 tion, assigning a part to each of these three names, Eocene, Miocene, 

 and Pliocene, there seems no reason to protest against the term. 

 The extent of country covered by these beds is so small, and their 

 disposition so irregular, that it seems necessary to suppose that a great 

 amount of erosion has acted upon the surface, and that only patches 

 of the ftmnation as it once existed, have remained to the present day. 

 These beds are of great value to us, however, merely as evidence of 

 long continued exposure of the low lands of this part of the Atlantic 

 shore. 



The bed of phosphate of lime which we have been preparing to 

 study, lies immediately on top of the " marls of the Ashley and 

 Cooper Rivers," as they have been generally termed, though these 

 beds are not limited to the basins of these streams. The whole of 

 the workable material lies in a single bed, from six inches to three 

 feet in thickness. Although it varies in its chemical and fossil com- 

 ponents, it retains everywhere certain marked features. It is always 

 more or less nodular; the nodules vary much in size, some being no 

 larger than a pea, some a foot or more in diameter. These nodules 

 contain, generally, one or more fragments of shells or corals, appar- 

 ently all Eocene species, which seem to have been the aggregating 

 points of the matter contained in the nodule. So far as my knowl- 

 edge goes, there have been few, if any, nodules found containing traces 

 of vertebrate remains. Many of the nodules show traces of wearing, 

 not exactly what would be expected from their being rolled as by a 



