322 ASSINNIBOINE AND SASKATCHEWAN EXPEDITION. 



[In the order of superposition, formation No. 1 rests 

 directly upon the true limestones of the coal measures. 

 Its first exposure seen along the Missouri is at Wood's 

 Bluffs, right bank, about eighty miles above the mouth of 

 the Platte, and it dips beneath the water level of the 

 Missouri, a few miles below the mouth of the Vermilion. 

 Its general character is a coarse grained, friable sand- 

 stone, very ferruginous, of a yellow or . reddish-yellow 

 colour, with thin beds of impure lignite and various 

 coloured clays. It contains very few fossils, mostly of 

 the genera Solen, Cyprina and Pectunculus, also fossil 

 wood, and numerous impressions of dicotyledonous 

 leaves, similar to the common willow. Its entire thick- 

 ness is estimated at ninety to one hundred feet, but it 

 may be more.] 



This formation has not yet been recognized in Eupert's 

 Land. In Nebraska it reposes upon the upper members 

 of the Carboniferous Series near the mouth of the Platte 

 (lat. 41° 40'), and it overlies Jurassic rocks at the Black 

 Hills.* 



FOKMATION NO. 2 OF VERTICAL SECTION. 



[This formation is first revealed in thin outliers below 

 the mouth of Big Sioux Eiver, and on that stream six 

 miles above its mouth, it caps the bluffs, apparently 

 mingling to some extent with the succeeding bed, and 

 containing at this locality large numbers of Inoceramus 

 problematicus and fragments of fishes. Near the mouth 

 of Iowa Creek and above, it shows itself worthy of a 



* Descriptions of the Species and Genera of Fossils collected by Dr. F. 

 V. Hayden in Nebraska Territory, under the direction of Lieut. 0. K. 

 Warren, U.S. Topographical Engineer, with some Remarks- on the Tertiary 

 and Cretaceous Formations of Nebraska, and the parallelism of the latter 

 with those of other portions of the United States and Territories, by F. B. 

 M., and F. V. Hayden, M.D. 



