NATURAL SCIENCES OP PHILADELPHIA. 425 



been discovered on the Saskatchewan by an expedition sent out by the Cana- 

 dian Government in 1858, under the direction of Prof. S. J. Dawson.* 



Several of the characteristic fossils of this formation were also discovered, in 

 1858, on the South Branch of the Saskatchewan, as well as on fie Assiniboine 

 and Little Souris Rivers, by another Canadian Government expedition, under 

 the charge of Prof. Henry Y. Hind.f 



This formation is also known to be well developed at the Black Hills and 

 along the Rocky Mountains west of there in Nebraska, and extends southward 

 a"t least as far as the region of Pike's Peak. It also exists in Texas, though it 

 probably only occurs as thin local patches in the country between the Rocky 

 Mountains and the Mississippi south of Nebraska. We had pointed out its pro- 

 bable existence in Texas in 1856 ;J and Dr. Shumard has, as we think, correctly 

 placed on a parallel with it the " Austin Limestone" and " Fish-bed" of his 

 section of the Texas Cretaceous rocks. 



The Fort Pierre Group is also known to be represented on the western bor- 

 ders of North America, or more properly, on Vancouver Island, as well as on 

 Sucia Islands in the Gulf of Georgia. || 



Coming eastward we find it again represented in New Jersey, and extending 

 thence through into Alabama and other Southern States. As long back as 

 1834, Dr. Morton had suggested in bis Synopsis of Organic Remains, p. 25, 

 that the beds at the Great Bend of the Missouri, are probably on a parallel 

 with the Green Sand of New Jersey. The identity of a few of the Nebraska 

 Cretaceous fossils with New Jersey species, was also pointed out by Prof. Hall, 

 and one of the writers (F. B. M.) in a paper published in the Memoirs of the 

 American Academy of Arts and Sciences, vol. 5, N. S., p. 406, 1854; though 

 too little was then known in regard to the range of the fossils in the Nebraska 

 beds, to warraut any attempt at drawing parallels between subdivisions. 



In Nov., 1856, after we had ascertained with some degree of accuracy the 

 position and range of particular species in tbe Nebraska series, and had learned 

 from the New Jersey Reports and from Prof. Cook, the range of the same forms 

 in New Jersey, we remarked that " the occurrence of several of the more 

 common and characteristic fossils of the upper two Nebraska formations, [Fort 

 Pierre Group and Fos Hill Beds,] such as Ammonites placenta, Scaphites Co?i- 

 radi, Baculites ovalus, Nautilus Dekayi" &c, in the first and second Green Sand 

 beds, and the intervening ferruginous stratum in New Jersey, as well as in the 

 " Rotten Limestone" of Alabama, clearly indicates the synchronism of these 

 deposits, notwithstanding their widely separated geographical positions.^" 



In May, 1857, we also submitted to the Academy another paper in which we 

 discussed more at length the relations of the Nebraska Cretaceous rocks 

 to those of New Jersey and other States, giving at the same time for com- 

 parison a section of the Cretaceous strata of Alabama, furnished by Prof. 

 Winchell, another of those in Northeastern Kansas, by Mr. Hawn, and a third 

 of the same in New Jersey, compiled from the Reports of Prof. Ketchell and 

 Prof. Cook.** 



* See Report Exploration of the Country between Lake Superior and the Red River 

 Settlement. Toronto, 1859, page 18. 



t For figures and descriptions of these fossils, see a paper by one of the writers in 

 Professor Hind's Report of the Saskatchewan and Assiniboine Expedition, page 182. 

 Toronto, 18o9. 



\ See note appended to the extra copies distributed by us, of a paper read before the 

 Academy, in JNov., 1856. 



Observations upon the Cretaceous Strata of Texas, by B. F. Shumard, M. D./State 

 Geologist- Trans. St. Louis Acad. Sci., vol. 1, page 583. 



|| See paper by F. B. Meek, describing Cretaceous fossils from Vancouver Island, in 

 Trans. Albany Institute, read Dec, 1856. Also another paper by same, in Proceed. 

 Acad Nat. Set. Phila., tor Oct., 1861. On the Collections uf N. W. Boundary Survey. 



f Proceed. Acad. JNat Sci. Phila., November. 18 >6, p. 267. 

 ** Proceed. Acad. Nat. Sci. Phila., May, 1857, p. 117. 



1861.] 



