NATURAL SCIENCES OF PUILADELPHIA. 117 



Explorations cmdee the War Department. 



Descriptions of new Species and Genera of Fossils, collected by Dr. F. V. Hayden 

 in Nebraska Territory, under the direction of Lieut. G. K. Warren, U. S. 

 Topographical Engineer ; with some remarks on the Tertiary and Cretaceous 

 formations of the north-west, and the parallelism of the latter with those 

 of other portions of the United States and Territories. 



BY P. B. MEEK and P. V. HAYDEN, M. D. 

 (Communicated by permission of the Secretary of War.) 



Most of the fossils, and many of the notes and memoranda upon -which this 

 paper is based, although collected previous to the presentation of our last com- 

 munication to the Academy, arrived in the States since that paper was in print. 

 Consequently, we have now not only the means of adding many new and in- 

 teresting species to the list of ancient moUusca previously knoAvn from Nebraska, 

 but the late explorations of Lieut. Warren have also brought to light some 

 additional information in regard to its general geology, which we have embodied 

 in the following remarks. 



Before presenting these facts and conclusions, justice to former explorers re- 

 quires that we should at least give a brief statement of the results of such 

 expeditions as have contributed to the development of the geology of this region. 



The first reliable accounts we have of the general physical characters of the 

 upper Missouri country, were given to the world in the report of Lewis and 

 Clark's expedition to the Columbia in 1804—5—6. The explorations of these 

 gentlemen, in addition to bringing out a large amount of information of a dif- 

 ferent character, established the fiict of the occurrence of Cretaceous rocks at 

 the Great Bend of the Missouri below Fort Pierre, and of the existence of what 

 was supposed to be " stone coal" (Lignite,) in the Mandan country. Various 

 beds of clay, sand, sandstone, &c., were mentioned in their report, but without 

 any suggestions respecting their age. 



In 1832, the Prince of Neu Wied and party also ascended the Missouri to its 

 sources ; and the results of his explorations, embodying a great amount of 

 highly interesting information respecting the geography, natural history, &c., 

 of the country explored, has been published in the form of a large quarto 

 volume, accompanied by a magnificent folio atlas of plates, illustrating the 

 scenery of the country, and the manners and customs of its native tribes, in a 

 style of art rarely equalled on this side of the Atlantic. Respecting the geology 

 of the country, however, the Prince's expedition added little of importance be- 

 yond the discovery of Mosasaurus Missouricnsis, to the results of Lewis and 

 Clark's expedition.* 



Mr. Nicollet, the well known Geographer, visited this country in 1839, as- 

 cending the Missouri to Fort Pierre, and making on his way up a fine collection 

 of Cretaceous fossils at the Great Beud.f Although passing rapidly through 

 the country, he formed a tolerably correct idea of its geology, and gave in his 

 report a vertical section of the Cretaceous rock seen below Fort Pierre, which 

 is correct, excepting that he seems to have had no knowledge of No. 2, and as 

 we think, without sufficient reason, represented two of the subdivisions of No. 3 

 as distinct formations ; No- 1 he appears to have referred to the carboniferous 

 system. As he did not go above Fort Pierre, he probably Saw nothing of No. 5, 

 though some of its characteristic fossils were presented to him by gentlemen 

 connected with the Fur company. 



♦The Prince lost nearly all of his gco'ogical specimens by the burning of the Far 

 Company's steam boat. 



f Th. se, togetiiei with others given to him at Fort Pierre, were inTPstigated by Dr, 

 Morton, and pubUshed in the Jour. Acad. Nat. Sc. Philada., Vol. 8, p. 207. 



1857.] 9 



