276 Organic Remains of the Ferruginous 
Deal to Salem ; let the Atlantic ocean connect the eastern, and the 
Delaware river the western points of these two lines. This irregu- 
lar oblong tract encloses nearly the whole of the marl region of New 
Jersey, so far, at least, as it has hitherto been explored; though 
there is reason to believe that this formation occupies a great propor- 
tion of the triangular peninsula south of the Raritan river. Much of 
the ferruginous sand region, however, is overlaid by deposits of clay, 
containing lignite, which have been referred, with apparent correct- 
ness, to the plastic clay formation. Above these clay beds is an al- 
most uniform covering of gray sand; yet in many places, however, 
the marl, with its peculiar fossils, is found immediately beneath the 
In Maryland commences a vast deposit of sand and clay, extend- 
ing coastwise to the Mississippi; this tract abounds with tertiary fos- 
sils, which appear chiefly to belong to the upper marine formation of 
the European geologists.* The secondary strata are occasionally 
met with beneath it, and sometimes approach so near the surface as 
to be readily identified by their fossils, as in Maryland, S. Carolina, 
Georgia,t &c. as already quoted. It is therefore reasonable to sup- 
pose that the beds of ferruginous sand extend nearly the whole length 
of the Atlantic frontier of United States south of Long Island, though 
Jor the most part concealed by the different members of the tertiary 
class. 
In all its localities this formation has been identified by similar gen- 
era and species of organic remains, though all the genera do not ex- 
ist in every locality. Thus, at the Deep Cut of the Chesapeake and 
Delaware Canal, the strata are characterized by great numbers of 
ammonites, baculites and other multilocular univalves. The same 
remarks will apply to various parts of Burlington and Monmouth 
counties in New Jersey. Near Egypt, in the latter State, we find 
_ ten or twelve beds one above the other, with the genera terebratula 
and gryphea. (Ostrea, Say.) Near Hornerstown the marl is ex- 
tremely indurated, and contains terebratule exclusively. Near 
Walnford, also in New Jersey, the fossils are chiefly exogyre and 
belemnites ; while at Mullica Hill, in Gloucester county, the beds 
. : : 
d Vide a paper by me in Jour. Acad. Nat. Se. Vol. VI. p. 116. 
and Mr. Peirce (Amer. Jour. Sc. Vol. XI. p. 54) mentions that gryphites and belem- 
‘Rites occur in that portion of Maryland and Virginia, marked alluvial on Mr. Ma- 
clures map, but he docs not give the particular localities. - 
