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GEOLOGY. 339 



with great numbers of marine mollusca, few land plants, and bones of Mo- 

 sasaurus. 4. Bluish and dark plastic clay, containing numerous marine 

 Mollusca. 3. Lead-gray calcareous marl, with scales of fishes. Ostrea con- 

 gesta, Inocenunus, etc. 2. Dark-gray laminated clay, with scales of fishes, 

 small ammonites, etc. 1. Heavy bedded yellowish sandstone, with water- 

 worn lignite. This formation, they say, may not belong to the cretaceous 

 system. 



Prof. Hall, in his Geological Report, August 1836, connected with Major 

 Emory's Mexican Boundary Survey, gives an excellent table, prepared by 

 Prof. G. H. Cooke, of the New Jersey Survey, which divides the whole of 

 this system in New Jersey into eight members, which may be thus succinctly 

 given : 



8. Greensand, 3d or upper bed. 



7. Quartzose Sand. 



6. Greensand, 2d. bed (a) Eschara, etc. 



(b) Gryphcea, etc. 



(c) Cucullea, etc. 



5. Quartzose Sand, highly ferruginous Exogyra, etc. 

 4. Greensand, 1st or lower bed Exogyra, Ostrea, etc. 

 . 3. Dark-colored clay, containing greensand Ammonites, Ddaicaren- 

 { sis, etc. 



2. Dark-colored clay Fossil wood, no animal remains. 

 1. Fire Clay and Potter's Clay Fossil wood and leaves, no animal 



remains. 



In May 1857, Mr. Meek and Dr. Hayden, in the Proceedings of the Acad- 

 emy, continued their valuable papers on the Tertiary and Cretaceous forma- 

 tion of Nebraska, and gave a table of equivalents with the New Jersey 

 deposits ; and Dr. Hayden, in June of the same year, made a communication 

 entitled " Explanations of a second edition of a geological map of Nebraska 

 and Kansas," in which the whole series of formations is reviewed, including 

 the cretaceous system. 



It is a very important matter, in discussing these organic remains, to as- 

 certain, as nearly as possible, the horizon on which this particular formation 

 would stand in regard to its parallelism with those of Europe, where so 

 much has been written on the subject of the various members of the Creta- 

 ceous group. Sir Charles Lyell says that the New Jersey "strata consist 

 chiefly of greensand and green marl, with an overlying coraline 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.* 



Prof. Rogers, in his New- Jersey Report, does not seem to agree with this 

 idea ; he " does not regard these strata as the equivalents, in the strict sense 

 of the word, of the greensand formation, so-called, of Europe " (page 178). 

 ' Nor are we able," he says, " positively to decide, merely by the relation- 

 ship of the genera, whether the cretaceous period embraces both the com- 

 mencement and termination of the American greensand series " (page 179). 

 M. D'Orbigny f considers the chalk formation of North America to belong 

 to his " e'tage senonicn " (the upper chalk of Morris), and not to the " gres 

 verts," as supposed by Dr. Morton and others. Dr. Mantell considered that 

 the teeth of the Mosasaurus, found in the greensand formation of New Jer- 



* Manual, third edition, p. 224. t Cours Elementaire, p. 671. 



