Ch. XVtt] CEETACEOUS ROCKS. 255 



a lower bed in the cretaceous series in New Jersey, appears to rest on 

 better evidence.* 



From New Jersey tbe cretaceous formation extends southwards to North 

 Carolina and Georgia, cropping out at intervals from beneath the tertiary 

 strata, between the Appalachian Mountains and the Atlantic. They then 

 sweep round the southern extremity of that chain, in Alabama and Mis- 

 sissippi, and stretch northwards again to Tennessee and Kentucky. They 

 have also been traced far up the valley of the Missouri, as far north as lat. 

 48°, or to Fort Mandan ; so that already the area which they are ascer- 

 tained to occupy in North America may perhaps equal their extent in 

 •Europe, and exceeds that of any other fossiliferous formation in the United 

 States. So little do they resemble mineralogically the European white 

 chalk, that in North America, limestone is upon the whole an exception 

 to the rule ; and even in Alabama, where I saw a calcareous member of 

 this group, composed of marl-stone, it was more like the English and 

 French Lias than any other European secondary deposit. 



At the base of the system in Alabama, I found dense masses of shingle, 

 perfectly loose and unconsolidated, derived from the waste of paleozoic (or 

 carboniferous) rocks, a mass in no way distinguishable, except by its position, 

 from ordinary alluvium, but covered with marls abounding in Inocerami. 



In Texas, according to F. Romer, the chalk assumes a new lithological 

 type, a large portion of it consisting of hard siliceous limestone, but the 

 organic remains leave no doubt in regard to its age, the Baculites anceps 

 and ten other European species occurring there. 



In South America the cretaceous strata have been discovered in Colum- 

 bia, as at Bogota, and elsewhere, containing Ammonites, Hamites, Inoce- 

 rami, and other characteristic shells.f 



In the south of India, also, at Pondicherry, Verdachellum, and Trin- 

 conopoly, Messrs. Kaye and Egerton have collected fossils belonging 

 to the cretaceous system. Taken in connection with those from the 

 United States, they prove, says Professor E. Forbes, that those powerful 

 causes which stamped a peculiar character on the forms of marine animal 



* In the Principles of Geology, ninth ed. p. 145, I cited Dr. Leidy, of Philadel- 

 phia, as having described (Proceedings of Acad. Nat. Sci. Philad. 1851) two 

 species of cetacea of a new genus which he called Priscodelphinus, from the 

 greensand of New Jersey. In 1853, 1 saw the two vertebrae at Philadelphia, 

 on which this new genus was founded, and afterwards, with the aid of Mr. Con- 

 rad, traced one of them to a Miocene marl pit in Cumberland county, New Jersey. 

 The other (the Plesiosaurus of Harlan), labelled " Mullica Hill" in the Museum, 

 would no doubt be an upper cretaceous fossil, if really derived from that 

 locality, but its mineral condition makes the point rather doubtful. The tooth 

 of Stenorhynchus vetus, figured by Leidy from a drawing of Conrad's (Proceed. 

 of Acad. Nat. Sci. Philad. 1853, p. 377), was found by Samuel R. Wetherhill, 

 Esq., in the greensand l£ miles southeast of Burlington. This gentleman re- 

 lated to me and Mr. Conrad, in 1853, the circumstances under which he met 

 with it, associated with Ammonites placenta, Ammonites Delawarensis, Trigonia 

 thoracica, <fcc. The tooth has been mislaid, but not until it had excited much 

 interest and had been carefully examined by good zoologists. 



f Proceedings of the Geol. Soc. vol. iv. p. 391. 



