220 
PROCEEDINGS OF THE ACADEMY OP 
In 1855, Mr. Marcou published, in the Bulletin of the Geological Society of 
France, an account of the Geology of the United States, in the cretaceous di- 
vision of which, (page 70,) after giving to Prof. Vanuxem the credit of being 
the first to detect this group in the United States, he says that it may be di- 
vided provisionally into " three great groups," which have been named in Eu- 
rope, 1st, le Neocomien ; 2d. le gres vert superieur et la craie marneuse ; 3d, 
la craie blanche. 
In March, 1856, Mr. Meek and Dr. Hayden, published their section of the 
Cretaceous formation of Nebraska, in the Proceedings of the Academy of Natural 
Sciences, which they republished more fully in the following November, also in the 
Academy's Proceedings. 
5. Gray and yellowish arenaceous clays, with great numbers of marine mol- 
lusca, few land plants and bones of Mosasaurus. 
4. Bluish and dark plastic clay, containing numerous marine Mollusca. 
3. Lead gray calcareous marl, with scales of fishes. Ostrea congesta, Inocera- 
musj &c. 
2. Dark gray laminated clay, with scales of fishes, small ammonites, &c. 
1. Heavy bedded yellowish sandstone, with water-worn lignite. This forma- 
tion they say may not belong to the cretaceous system. 
Prof. Hall in his Geological Report, August, 1856, 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 suscinctly given : — 
8, Green Sand, 3d or upper bed. 
7. Quartzose Sand, 
i fa. Green Sand, 2d bed— (a) JEschara, &c. 
w I (b) Gryphcea, &c. 
52 J d j (c) Cucullea, &c. 
^5 .2 j 5. Quartzose sand, highly ferruginous — Exogyra^ &c. 
oS ^ I 4. Green Sand, 1st or lower bed — Ezogyra^ Ostrea, &c. 
>^ L 3. Dark colored clay, containing green sand — AvimonitesDelawarensis^hc. 
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 Academy, 
continued their valuable papers on the Tertiary and Cretaceous formation 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 " Expla- 
nations 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 ascertain, 
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 Cretaceous group. 
Sir Charles Lyell says, that the New Jersey " strata consist chiefly of green 
sand and green marl, with an overlying coraline limestone of a pale yellow col- 
or, and the fossils, on the whole, agree most nearly with those of the upper Eu- 
ropean series from the Maestricht beds to the gault inclusive." ^' 
Professor 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 green sand formation, so called, of Europe" (page 178). "Nor 
are we able," he says, " positively to decide, merely by the relationship of the 
genera, whether the cretaceous period embraces both the commencement and 
termination of the American green sand series" (page 179). 
M. D'Orbigny f considers the chalk formation of North America to belong to 
* Manual, third edition, page224. 
t Cours Elementaire, page 671. 
[Dec. 
