﻿102 Dr. J. L. Smith on the Marl from Ashley River. 



have been sent to Prof. Bailey of West Point, who has already 

 subjected them to microscopic examination, and a short account 

 of his results will be found in the accompanying note. # A fuller 

 detail may be expected from him at some future time, and when 

 it does come it will no doubt be a rich feast for the naturalist of 

 this country, prepared as it will be by a skillful hand. 



* Extract of a letter from Prof. Bailey to J. L. Smith. — u Charleston is built upon 

 a bed of animalcules several hundred feet in thickness, every cubic inch of which 

 is filled with myriads of perfectly preserved microscopic shells. These shells 

 however do not, like those beneath Richmond and Petersburg, &c, belong to the 

 siliceous infusoria, but are all derived from those minute calcareous-shelled crea- 



tures, called by Ehrenberg Polythalamia, and by D'Orbigny the Foraminifera. 

 You are aware that Ehrenberg proved chalk to be chiefly made up of such shells, 

 and you will doubtless be pleased to learn that the tertiary beds beneath your city 

 are filled with more numerous and more perfect specimens of these beautiful forms 

 than I have ever seen in chalk or marl from any other locality. " 



"The following are some of the results I have obtained : 



"1. The marls from the depth of 110 feet to 193 feet are certainly tertiary de- 

 posits, for I found them to contain Polythalamia of the family Plicatilia of Ehren- 

 berg, (Agathestegens of D'Orbigny,) which family as far as is yet known occurs 

 in no formation older than the tertiary. 



" 2. The beds from the depth of 193 feet to 309 feet contain so many species in 

 common with the beds above them, that although I have not yet detected the Pli- 

 catilia, I yet believe they must also belong to the tertiary formation. 



"3. The forms found in these beds agree much better with those detected by me 

 in the eocene marls from Panumkey River, Virginia, than they do with miocene 

 Polythalamia from Petersburg, Va., and I am consequently inclined to believe that 

 they belong to the eocene epoch. 



" 4. All the marls to the depth of 236 feet present the Polythalamia in vast 

 abundance, and in a state of surprising preservation. The most delicate markings 

 of the shells are perfectly preserved, and some of the forms are so large that they 

 may be easily seen with a common pocket-lens. 



"5. The lithological characters of the marls from 236 feet to 309 feet differ from 

 those above, and although the Polythalamia are still abundant, and many of the 

 species appear to be the same as in the strata above, yet they are less easy to ob- 

 serve on account of the greater compactness of the marls, and the adherence of 

 crystalline calcareous particles to the shells. 



"6. The marls which you sent from the Cooper River, 35 to 38 miles above 

 Charleston, also abound in Polythalamia, and so many of the species are identical 

 with those found beneath Charleston, that they most probably belong to the same 

 formation. This place on the Cooper River may be the outcrop of the very slight- 

 ly inclined beds which exist under Charleston. [In this conclusion Prof. Bailey is 

 correct. — J. L. S.] 



"7. The Polythalamia to whose labors South Carolina owes so large a portion of 

 her territory, are still at work in countless thousands upon her coasts, filling up 

 harbors, forming shoals, and depositing their shells to record the present state of 

 the sea-shore, as their predecessors, now entombed beneath Charleston, have done 

 with regard to ancient oceans. The mud from Charleston harbor is filled not only 

 with beautiful Polythalamian shells, but is also very rich in siliceous infusoria." 



