42 Phosphate Rocks of South Carolina, 
A CHAPTER ON THE ASHLEY MAEES. 
We have said that the Ashley Marl and Sands com- 
pose the Fish-bed of the Charleston Basin, because 
from them the varieties of Sharks’ teeth were obtained, 
that are now taken from the Phosphate Beds. The 
Marl proper, contains but a small percentage of Phos- 
phate of Lime, it is larger near the surface than at 
greater depths, and it is reasonable therefore, to infer, 
that the juices from the upper beds of Phosphate-rocks, 
being in excess, passed through the intervening sand 
and clays, percolated the soft Marl below, and was 
absorbed by its upper layers; hence we find such 
Marls as are or have been covered by Phosphate- 
rocks, phosphatic for a few feet below the surface, whilst 
others not thus covered contain only a small amount 
of this substance, and which was derived from marine 
animals imbedded in this great Eocene formation, 
deposited at the bottom of the Ocean. 
