HAYDEN'S SUBVEY. 13 



Philadelphia Academy of Natural Sciences,* and in the following year 

 another map was published by him in the Proceedings of the Philadelphia 

 Academy, together with the results of his expedition with Lieutenant 

 Warren to the Black Hills. The most important publication, however, 

 including all his observations to date, was read as a memoir by Dr. Hayden 

 before the American Philosophical Society of Philadelphia in 186 l,f being 

 accompanied by a map. The descriptions by Dr. Leidy of the vertebrate 

 remains collected in these various expeditions appeared at different times 

 in the Proceedings of the Philadelphia Academy of Natural Sciences, and 

 form a most important contribution to our knowledge of these very inter- 

 esting fossils. Much of the same material, with the addition of that since 

 collected in other parts of the Far West, appears in a more accessible form 

 in a quarto publication of the Geological Survey of the Territories. J The 

 molluscan collections of the formations of the Upper Missouri have been 

 described and published through the Philadelphia Academy of Natural 

 Sciences by Messrs. Meek and Hayden and form the subject of one of the 

 memoirs issued by the Smithsonian Institution. § 



In 1 859 Captain (now Colonel) J. H. Simpson, United States Engineers, 

 made a survey for a wagon road across the Great Basin of Utah, and the 

 records of the route from Fort Leavenworth to Fort Laramie and South Pass 

 contain many valuable facts regarding the geology of the southern part of 

 the Upper Missouri region. The geologist was Mr. Henry Engelmann.|| 



In 1866 Dr. Hayden again visited the Bad Land region of the Nio- 

 brara and White Rivers, and in the following year the " Geological Sur- 

 vey of the Territories," in his charge, was begun under the auspices of 

 the Commissioner of the General Land Office. The work was commenced 

 in Nebraska, and in the following year was extended into Wyoming, but 

 it embraced only the southern portion of that Territory and the northern 



* Notes explanatory of a map and section illustrating tlie geographical structure of the country- 

 bordering the Missouri. May, 1857. 



t On the Geology and Natural History of the Upper Missouri, with map. Trans. Am. Phil. Soc. 

 Philadelphia, July 19, 1661. 



t Contribnt ion to the Extinct Vertebrate Fauna of the Western Territories, by Joseph Leidy. 4to, 

 pp. 358, pi. 37. Washiugtou, 1673. 



§ Paleontology of the Upper Missouri. Part 1. F. B. Meek and F. V. Hayden. Washington, 1865. 



|| Exploration across the Great Basin of Utah, 1859, by Capt. J. A. Simpson. (Geology by H. 

 Englemann.) 5to. Engineer Department, 1876. 



