Sand Formation of the United States. 277 
contain all the bivalves of which we have spoken, and quantities of 
belemniies. 4 ; 
The calcareous beds of Gloucester county contain gryphwa, tere- 
do, aleyonium? spatangus, and several species of Linnean madre- 
pores. Crossing the Delaware river into the state of Delaware, we 
find at St. Georges and its vicinity, great numbers of the genera 
gryphea, exogyra, and ostrea.* We have already adverted to the 
multilocular shells of the deep cut of the Chesapeake and Delaware 
canal, to which we may add the genus spatangus, and several other 
genera of echinidee. The green sand below Annapolis, in Mary- 
land, contains aleyonia. At Lynch’s Creek, in South Carolina, exo- 
gyre occur, specifically the same with those of New Jersey and 
Delaware. At Cockspur Island, in Georgia, the formation is recog- 
nized by a prodigious quantity of belemnites. ‘The localities here 
enumerated will serve to convey a good idea of the productions of 
nearly all the others. 
Mineralogical Characters. | 
These vary considerably ; but our marl most frequently presents 
itself in minute grains, loose and friable, and of an uniform dull bluish, 
or greenish color, often with a shade of gray. A hundred grains of 
this variety gave Mr. Seybert the following constituents: - 
ex, == - - - 49.83.--27:, 
Alumine, = - - - - =~ B09 -- 
Magnesia, - - - - 1.83: 
Potash, - - nome | - + 182: 
Water, - - -— - - ny GBD <0 
Protoxide of Iron, = - - - o=; 21.68.25, 
hoes, =.= - " - 89. 
100.00 
In a less cautious analysis by Mr. J. P. Wetherill and myself, of 
an apparently similar marl from another locality, we obtained silex 
49.00, protoxide of iron 30.00, alumine 5.50, lime 4.70, the re- 
mainder being chiefly water and carbonic acid. Hence it appears 
the predominant constituents of these varieties of marl, are silex 
and iron. ‘They ofien contain beds of a dark bluish, tenacious clay ; 
*The same fossils appear to abound at Middletown Point, and its vicinity in N.S. 
This locality, however, I have not been able to visit. 
