THE NEBRASKA VERTICAL SECTION. 319 



Fort a la Corne, thence north-westerly. Cretaceous 

 rocks were recognized by Dr. Hector * at the Snake 

 Portage, in lat. 54° long. 111° 30'; also on Little Bed 

 Deer Eiver, at the base of the Eocky Mountains, in long. 

 114°. 



This important series, as it occurs in Nebraska, has 

 been carefully studied by Messrs. Meek and Hayden. In 

 the notes explanatory of a map and section illustrating 

 the geological structure of the country bordering on the 

 Missouri Eiver, Dr. Hayden has described the rocks of 

 Nebraska Territory f , where the Cretaceous Series is best 

 developed ; and as this division, styled the Nebraska Sec- 

 tion, forms the standard to which the Cretaceous rocks of 

 the north-west are referred on the American Continent, 

 the following division of the series in Eupert's Land is 

 based upon the Nebraska Section. 



The vertical section of the geological formations of 

 Nebraska Territory, with their extension into Eupert's 

 Land, as far as determined, is given on pp. 320, 321. 



FORMATION NO. 1, OF VERTICAL SECTION. 



The following excellent descriptions, enclosed in 

 brackets, of the formations constituting the Nebraska 

 Section, are from the clear and concise " Notes Explana- 

 tory of a Map," &c, by F. B. Meek and F. V. Hayden, 

 M.D. They are introduced here for the purpose of com- 

 parison with the development of the same formations in 

 Eupert's Land. 



* Papers relative to the Exploration of British North America. Blue 

 Book, 1859. 



f Notes explanatory of a Map and Section illustrating the Geological 

 Structure of the Country on the Missouri River from the Mouth of the Platte 

 River to Fort Benton, in lat. 47° 30 / N., long. 110° 30' W., by F. V, 

 Hayden, M.D. Proc. Acad. Nat, Sci. Phil., May, 1857. 



