428 PROCEEDINGS OP THE ACADEMY OP 



I 

 Hind's Exploring Expedition in the British Possessions, on the South Branch of 

 the Saskatchewan ; and, what is a little remarkable, they occur in a green 

 sand matrix, much like that in New Jersey, excepting that it is more in- 

 durated. 



At the Black Hills, and along the Rocky Mountains west of there, the Fox 

 Hills Beds are generally well developed. They also occur at Deer Creek on the 

 North Platte, and along the mountains southward at least to the region of 

 Pike's Peak. South of this they have not yet been certainly identified as a 

 distinct rock. 



As already stated, we had pointed out, in Nov., 1856, and in May, 1857, that 

 this rock is represented by the upper portion of the Cretaceous beds in New 

 Jersey, (the beds b, c, d and e of the section on page 426 of this paper,) and by 

 the Rotten Limestone of Alabama. 



The intimate relations between the Fox Hills Beds and the Fort Pierre Group, 

 already mentioned, make it necessary, when we undertake to trace out the rela- 

 tions between our Cretaceous rocks and those of the Old World, to view these two 

 formations together as one series. Their synchronism with particular portions of 

 the Cretaceous system, at British and other foreign localities, will also be more 

 clearly understood by keeping in view, as a half-way ground, their representa- 

 tive beds in New Jersey, which certainly coutain a few foreign species. The 

 evidence of the equivalence of our Upper Cretaceous Series of Nebraska with 

 the upper four divisions of the Cretaceous in New Jersey, b, c, d and e of the 

 section on page 42G of this paper, (which we must also take collectively, when 

 we wish to compare them with particular horizons of the Cretaceous abroad), 

 will be more clearly understood by consulting the following list of species com- 

 mon to the New Jersey and Nebraska Upper Cretaceous Series : 



New Jersey Species. Position in Nebraska Upper Series. 



Mosasaurus Missouriensis Ranges through the whole Upper Series. 



Nautilus Dekayi Upper zone Ft. P. G. and in F. H. Beds, 



Scaphites Conradi Fox Hills Beds. 



Ammonites placenta Upper zone Ft. P. G. and F. H. Beds. 



A. complexus , Lower zone Ft. Pierre Group. 



A. lobatus Fox Hills Beds. 



Baculilcs ovatus Ranges all through Ft. P. Group. 



Amauropsis paludina-fdrmis* Lower zone Ft. P. Group. 



We have reason to believe several other species are common to the Upper 

 Series in Nebraska and New Jersey, but we only include in this list those about 

 which there can be no doubt. A list of the closely allied representative species 

 at these distant localities, would, if accompanied by figures, still more clearly 

 illustrate the synchronism of the rocks under consideration. 



RELATIONS OF THE UPPER CRETACEOUS SERIES OF NEBRASKA TO EUROPEAN DIVISIONS. 



Before expressing any opinion in regard to the parallelism of our Upper Cre- 

 taceous Series of Nebraska, with particular portions of the Cretaceous of the 

 old world, it is proper that we should give a brief statement of the views of 

 others on this point, as well as in relation to the age of equivalent beds in New 

 Jersey, and in the States farther south. 



As is now well known, the Cretaceous strata of New Jersey were first referred 

 to that epoch by the lamented Prof. Lardner Vanuxem ; who did not, however, 

 attempt to trace out close parallels between particular beds of the New Jersey 

 strata, and their exact equivalents in the old world. Dr. Morton, to whom we 

 are indebted for figures and descriptions of a large number of the New Jersey 

 fossils, regarded these rocks and their equivalents in Nebraska and the South- 



* This species has been identified in New Jersey by Dr. Isaac Lea. 



[Dec. 







