And the “ Great Carolina Marl Bed.” 71 
As you approach the edges of the Phosphate-rock 
basins the stratum thins out. The outlines of these 
basins are as irregular as those of the ponds and lakes 
of the present period. The upheaval of the coast of 
South Carolina was very gradual, not sudden. The 
Ashley Basin was lifted and rent near its centre; and 
thus a channel for the river was made, as seen in Plate 
Ill. The stratum underlies the City of Charleston, 
and is reached at the depth of sixty feet. 
Plate IV is an illustration of the relative position of 
the Eocene Marl; sands and clays, with imbedded 
shells of the Post-Pleiocene period, the strata of Phos- 
phate-rocks in situ, under the marsh, and also as cov- 
ered by the sedimentary formation of river mud. 
The shells in beds are found sometimes above the 
Phosphate-rock stratum. 
Why vtrVALUE OP THESE: BEDS WAS 
NOE DISCOVERED THIRTY YEARS AGO, 
How often have we heard this question, and per- 
haps we will hear it again and again! There is but 
one answer, and that was given in our description of 
the Phosphate Beds of South Carolina, before the 
American National Academy of Science at Washing- 
ton, as follows: 
A few years ago the lands in Western Pennsylvania 
were selling at ‘sheriffs’ prices ;’ the forests had all 
or nearly all been cut down and consumed, and every 
source from whence fuel could be obtained exhausted. 
