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 

 soil. 



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, •]■ &;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 

 for 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 C'ut 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 gryphsea. (Ostrea, Say.) Near Hornerstown the marl is ex- 

 tremely indurated, and contains terebratulae exclusively. Near 

 Walnford, also in New Jersey, the fossils are chiefly exogyrse and 

 belemnites ; while at Mullica Hill, in Gloucester county, the beds 



* Vide a paper by me in Jour. Acad. Nat. Sc. Vol. VI. p. 116. 



I Mr. Peirce (Amer. Jour. Sc. Vol. XI. p. 54) mentions that gryphites and belem- 

 nites occur in that portion of Maryland and Virginia, marked alluvial on Mr. Ma- 

 clures map, but he does not give the particular localitie?. 



