162 GEOLOGICAL SURVEY 
This list presents a very different result from that obtained from the fossils of the buhr-stone, for 
besides the introduction of the classes Cephalopoda and Pteropoda, there is a great numerical fall- 
ing off in the Gasteropods; and yet the occurrence of oysters in all these beds, and of corals in 
some of them, would indicate a sea of no great depth at the time of their deposition. 
The following are the numerical proportions of the classes. 
Cephalopoda ...... 3 species, or 6 per cent. 
Pteropodat Aiieecrieo = Taletassit 46° 
Gasteropodag-Wy i.) 1 (Olmins: LSS aK 
Lamellibranchiata... 20 “ HORS, 
36 species. 
Eocene Beps oF THE ASHLEY AND Cooper Rivers. 
Next in order above the Santee beds, are those exposed to view on the banks of the Ashley and 
Cooper, and their tributaries. 
The marl of these beds, particularly towards their southern extremity, differs, both in external 
appearance and embedded fossils, from that of the Santee beds. In general, the structure of the 
marl is loose and granular, and the color dark gray, sometimes approaching olive—the latter is par- 
ticularly the case with the Ashley marl, when recently taken from below the surface. This dark 
color is frequently due to minute particles of carbonaceous matter dissemminated through the mass. 
It will be seen that the most remarkable feature connected with the organic forms entombed in 
these beds, is the vast number of the remains of fishes that they include, and hence the very nota- 
ble amount of phosphate of lime in the marl. 
Mr. Ruffin has shown that these beds underlie the city of Charleston, by identifying the spe- 
cimens taken from an Artesian well,* (attempted in the city, in 1824,) with the Ashley marl. He 
also showed that this marl forms the bottom of Charleston harbor, specimens often being brought 
up by the anchors of vessels and the tackle of fishermen. 
From fossils picked up on Beresford Creek, between Cooper and Wandoo, f infer that marl must 
be found on its banks; but the lowest point at which I observed Eocene beds is near Bonneau’s 
Ferry, on the eastern branch of Cooper. At Dr. Prioleau’s mill, marl is exposed to a considerable 
extent, just below the dam, on the sides and bottom of the race. 
It is again laid bare, at low water, below Strawberry Ferry, on the left bank of the river, and a 
short distance above, on the plantation of J. Harleston, Esq. in a fine natural section, which was 
once the river bank, but is now removed from it by the extent of a rice plantation. ‘The marl is 
yellowish and pulverulent, and presents no marks of stratification. 
I found here, embedded in the face of the bluff, nodules rather whiter than the rest, containing 
an amount of chloride of sodium, or common salt, quite perceptible to the taste. I did not visit 
A 
* Since this was written I had an opportunity of examining the borings from the wells at present in progress, in the city and at 
Fort Sumter. The marl brought up has the dark or grey color characteristic of that of the Ashley, and like that, it abounds in 
those beautiful little forms, Polythalamia and Foraminifera. I had the pleasure of finding, through the politeness of Capt. Bow- 
man, that the green sand had been reached, at a depth of nearly 300 feet, at Fort Sumter, confirming the conclusion I had arrived 
at, from observations made elsewhere, on the dip of the beds of the Charleston Basin. 
