CRETACEOUS ROCKS OE AMERICA. 
307 
Cretaceous Rocks in the United States. —If we pass to the 
American continent, we find in the State of New Jersey a 
series of sandy and argillaceous beds wholly unlike in min¬ 
eral character to our Upper Cretaceous system; which we 
can, nevertheless, recognize as referable, palseoiitologically, 
to the same division. 
That they were about the same age generally as the Euro¬ 
pean chalk and Neocomian, was the conclusion to which Dr. 
Morton and Mr. Conrad came after their investigation of the 
fossils in 1834. The strata consist chiefly of green sand and 
green marl, with an overlying coralline limestone of a pale 
yellow color, and the fossils, on the whole, agree most nearly 
with those of the Upper European series, from the Maestricht 
beds to the Gault inclusive. I collected sixty shells from the 
New Jersey deposits in 1841, five of which were identical 
with European species— Ostrea larva^ 0, vesiciilaris^ Gryplima 
costata^ Pecten qumque-costatus^ Pelemnitella mucronata. As 
some of these have the greatest vertical range in Europe, 
they might be expected more than any others to recur in 
distant jDarts of the globe. Even where the species were 
different, the generic forms, such as the Baculite and certain 
sections of Ammonites, as also the Inoceramus (see above, 
Fig. 252, p. 295) and other bivalves, have a decidedly creta¬ 
ceous aspect. Fifteen out of the sixty shells above alluded 
to were regarded by Professor Forbes as good geographical 
representatives of well-known cretaceous fossils of Europe. 
The correspondence, therefore, is not small, when we reflect 
that the part of the United States where these strata occur 
is between 3000 and 4000 miles distant from the chalk of 
Central and Northern Europe, and that there is a difference 
of ten degrees in the latitude of the places compared on op¬ 
posite sides of the Atlantic. Fish of the genera Lamna^ 
Galeus^ and Gcifcliarodon are common to New Jersey and 
the European cretaceous rocks. So also is the genus Mosa- 
scmriis among reptiles. 
It appears from the labors of Dr. Newberry and others, 
that the Cretaceous strata of the United States east and west 
of the Appalachians are characterized by a flora decidedly 
analogous to that of Aix-la-Chapelle above mentioned, and 
therefore having considerable resemblance to the vegetation 
of the Tertiary and Recent Periods. 
