NATURAL SCIENCES OF PHILADELPHIA. 
221 
his " etage senonien" (the upper chalk of Morris) and not to the "gres verts," 
as supposed by Dr. Morton and others. 
Dr. Mantell consideied that the teeth of the Mosasaurus, found in the green 
sand formation of New Jersey, described by Dr. Harlan, were in every respect 
analogous to those of the Maestricht reptile, and that the deposit was equivalent 
to the Maestricht bed. 
The Blackdown green sand of Dr. FittonJ has in its fossil mollusca a very 
strong resemblance to our green sand fossils, and as D'Orbigny makes this for- 
mation an equivalent to his Cenomanien, there is some evidence that the New 
Jersey green sand may be on the same horrizon; for according to D'Orbigny's ta- 
bles the genus Belemnites ceases with the Cenomanien, and we have abundance 
of that genus in our green sand formation. If he be correct as to the decadence 
of the Cephalopoda, then we could not place this formation higher up in the se- 
ries than his Cenomanien, which is the " Glauconie crayeuse " of Brogniart, found 
at Cap le Heve in France, the Blackdown green sand of Fitton and the Upper 
green sand of Mantell in the south of England. 
Under all the information, we have, however, from the various investigations 
made by so many distinguished geologists, T think the evidence is in favor of 
D'Orbigny's opinion, that the green sand formation, from which these fossil re- 
mains were exhumed, belong to his Senonien, but it may prove upon further ex- 
amination to be a little lower ia the Cretaceous series. 
That portion of the grey micaceous clay at Haddonfield, in which the Mol- 
lusca^ all marine, were generally found, was some ten feet from the surface of 
the soil. The declination of the layer is very gentle and towards the south 
east. The bones and coniferous wood were so near or interspersed with the 
shells as to tend to prove that they must have lived in the vicinity of the shores 
which the Mollusca inhabited, for these show that they were deposited in a 
sediment totally and completely at rest. The most tender and delicate forms 
remain without abrasion, and usually, in the case of the bivalves, the two valves 
are attached. The great tenacity, however, of the clay, and the extreme ten- 
derness of the shells, render it almost impossible to get out perfect specimens, 
and when they come under the action of the atmosphere, and become de- 
siccated, the calcareous matter crumbles to pieces, the base membrane compos- 
ing the animal portion of the shell having been previously entirely absorbed. 
I propose here to give a hasty list of the genera which were collected, reserv- 
ing for a future time, when more at leisure, the specific diflFerences of those 
which are new. It will be observed that the Lamellibranchia greatly prevail 
over the Gasteropoda. 
List of Genera : — Pinna, I species ; Inoceramus, 2 do. ; Ostrea, 3 do. ; Anomia, 
1 do. ; Corbula, 2 do. ; Area, 1 do. ; Cardita, 1 do. ; Exogyra, 1 do. ; Siliquaria, 
2 do. ; Nucula, 3 do. ; Trigonia, 1 do. ; Tellina, 2 do. ; Pecten, 2 do. ; Turritella, 
1 do. ; Dentalium, 1 do. ; Natica, 1 do. ; Buccinum, 1 do. , Pterocera, (?) 1 do. ; 
Ammonites, 2 do.; Scaphites, (?) 1 do.; Echinus, 1 do., (spines of); Eschara, 1 
do. ; 1 Ooprolite ; 2 small vertebrae of fishes. 
Dr. Hammond observed in relation to the fragments of fossil wood found in 
the same locality as the bones and shells described this evening by Dr. Leidy 
and Mr. Lea, that he had submitted them to a careful examination, the details 
of which might prove of interest to the Academy. 
Upon inspecting the pieces of this wood placed upon the table, it will be per- 
ceived that they are all of an intensely black color, but differ greatly in degree 
of hardness. One specimen is so soft as to crumlble readily on the slightest 
handling; whilst another is dense and hard, and capable of receiving a high 
polish. Several of the fragments exhibit teredo perforations, a circumstance of con- 
siderable interest. These perforations are so completely filled with sulphuret of 
iron that casts of them are readily obtained. All the fragments are more or less im- 
1858.] 
X strata below the Chalk. 
