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 mineral character to our Upper Cretaceous system; which we can, nevertheless, recognise as referable, palæontologically, to the same division. That they were about the same age generally as the European 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 colour, 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, O. vesicularis, Gryphæa costata, Pecten quinque-costatus, Belemnitella mucronata._ As some of these have the greatest vertical range in Europe, they might be expected more than any others to recur in distant parts 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 Fig. 252) and other bivalves, have a decidedly cretaceous 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 opposite sides of the Atlantic. Fish of the genera _Lamna, Galeus,_ and _ Carcharodon_ are common to New Jersey and the European cretaceous rocks. So also is the genus _Mosasaurus_ among reptiles. It appears from the labours of Dr. Newberry and others, that the Cretaceous strata of the United States east and west of the Appalachians are characterised 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. [1] For particulars of structure see p. 318. [2] Geol. Trans., 1st Series, vol. iv, p. 413. [3] In this and subsequent remarks on fossil plants I shall often use Dr. Lindley’s terms, as most familiar in this country; but as those of M. A. Brongniart are much cited, it may be useful to geologists to give a table explaining the corresponding names of groups so much spoken of in palæontology. [4] D’Archiac, Sur la form. Crétacée du S.-O. de la France Mém. de la Soc. Géol. de France, tome ii. [5] D’Orbigny’s Paléontologie français, pl. 533. CHAPTER XVIII. LOWER CRETACEOUS OR NEOCOMIAN FORMATION.