/. Hall on the Cretaceous Strata of the United States. 79 



bama, while we have yet no evidence that Nos. 2 and 3 do occur 

 in either of these States. 



The beds Nos. 3, 4, 5 and 6, of the New Jersey section, given 

 on a preceding page, correspond in their fossils with Nos. 4 and 

 5, of the Nebraska section; leaA^ing the 3d greensand of New 

 Jersey (No. 8 of that section) unrepresented in the northwest, 

 so far as known at the present time. 



The New Jersey beds Nos. 1 and 2, which are marked only 

 by fossil wood and impressions of leaves^ appear to be repre- 

 sented by No. 1 of the Nebraska section, judging from the gen- 

 eral character of the remains yet known in the two. Should this 

 ^ inference prove to be correct, the beds Nos. 2, and 3, of the Ne- 



braska section, will hold a position between Nos. 2 and 3 of the 

 New Jersey section; but I do not regard this question as yet 

 determined. 



The relations of the beds Nos. 2 and 3 of the Nebraska sec- 

 tion, and their characteristic fossils, become very important when 

 we undertake the comparison of the cretaceous formation of 

 Texas and New Mexico, with those of Nebraska, Alabama and 

 New Jersey. 



The persistence and wide distribution of Inoceramits prdblemat- 

 tcuSj and its restriction to beds Nos. 2 and 3, and their equiva- 

 lents so far as at present known, render it of great value in 

 determining a geological horizon. This species was brought from 

 the Missouri Kivcr by Mr. Nicollet.* It was collected by Capt. 

 now Col. Fremont,! upon the Smoky Hill Fork; where it occurs 

 in a gray or buff-colored, and also in a blue, slaty limestone, in 

 great numbers; and being extremely flattened, gives to the rock 

 a slaty structure, as described by Mr. Nicollet. 



The specimens collected by Lt. Abert^: at Poblazon, are 

 doubtless of this species ; and are referred to by Prof. Bailey to 

 the same species as those of Fremont's Report. The same spe- 

 cies was brought by Capt. Staiisbury§ from between the Big and 



-*, 



* Report on the Upper Mississippi River, by J. N. Nicollet, 1843. 



•f- Report of the Ibcploring Expedition to the Rocky Mountains, by Capt. J. C. 

 Fremont, 1845. Appendix Geological Formations and Organic Remains, by James 

 Hall. At the time of my examination of Capt, Fremont's collection, I had an op- 

 portunity of comparing the specimens of Inoceramus with those brought from the 

 Missouri by Mr. Nicollet, and identified the specimens in the two collections as the 

 same species. The collections of Mr. Nicollet were at that time broken up, and I 

 saw some of them in Prof. Ducatell's possession in Baltimore, and others in George- 

 town. The information given me was, that they were from near the Great Bend of 

 the Missouri ; but from the examination of Mr. Nicollet's Report, it is very clear, 

 from his statements, p. 36, that this Inoceramus occurs at Dixon's Bluff and not at 

 Great Bend, since Mr. Nicollet refers to the former locality as exliibiting the base 

 of the formation. 



X Report on a Geographical Examination of Xew Mexico, by Lieut. J. W. Albert, 

 1848. Notes concemmg the minerals and fossils by Prof. J. W. Bailey, page 547. 



^ Exploration of the Valley of the Great Salt Lake by Capt. Howard Stansbury, 

 1852. Appendix Geology and Palaeontology, by James Hall; page 402. 



