254: CRETACEOUS ROCKS. [Ch. XVII 



situated, and the Pyrenees, the space B intervenes. (See Map, fig. 292.) 

 Here the tertiary strata cover, and for the most part conceal, the cre- 

 taceous rocks, except in some spots where they have been laid open by the 

 denudation of the newer formations. In these places they are seen still 

 preserving the form of a white chalky rock, which is charged in part with 

 grains of greensand. Even as far south as Tercis, on the Adour, near 

 Dax, cretaceous rocks retain this character where I examined them in 

 1828, and where M. Grateloup has found in them Ananchytes ovata 

 (fig. 253), and other fossils of the English chalk, together with Hipjmrites. 



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 our Upper 

 Cretaceous sj^stem ; which we can, nevertheless, recognize as referable, 

 paleontologically, to the same division. 



Thf.t they were about the same age generally as the European chalk 

 and greensand, was the conclusion to which Dr. Morton and Mr. Conrad 

 came after their investigation of the fossils in 1834. The strata consist 

 chiefly of greensand 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. vesicularis, Gryphcea costata^ Pecten quinque-costatus, Belemnites 

 mucronatus. 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 are different, the generic forms, such 

 as the Baculite and certain sections of Ammonites, as also the Inocera- 

 mus (see above, fig. 274) and other bivalves, have a decidedly cretaceous 

 aspect. Fifteen out of the sixty shells above alluded to Avere 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 oj^posite sides of the Atlantic^' 



Fish of the genera Lamna, Galeus, and Carclmrodon are common to 

 New Jersey and the European cretaceous rocks. So also is the genus 

 Mosasauims among reptiles. The vertebra of a Plesiosaurus, a reptile 

 known in the English chalk, had often been cited on the authority of 

 Dr. Harlan as occurring in the cretaceous marl, at Mullica Hill, in New 

 Jersey. But Dr. Leidy has since shown that the bone in question is not 

 saurian but cetaceous, and whether it can truly lay claim to the high 

 antiquity assigned to it, is a point still open to discussion. The discovery 

 of another mammal of the seal tribe (Stenorhynchus vetufi, Leidy), from 



* See a paper by the author, Quart. Journ. Geol. Soc. vol. i. p. 79. 



