206 Lull — Development of Vertebrate Paleontology. 



world. Leidy's interest in the horses, for the forward- 

 ing of which he made a large collection of recent mate- 

 rial, extended over many years, as his first paper on the 

 subject bears the date of 1847, the last that of 1890. 



Next came the discovery of Eocene material from the 

 vicinity of Fort Bridger, Wyoming, geologically older 

 than the Nebraska and Dakota formations. This, 

 together with specimens from the Green River and 

 Sweetwater River deposits of Wyoming and the John 

 Day River (Oligocene) of Oregon, was also referred to 

 Leidy, and added yet more to the list of newly discov- 

 ered species with which he had already become familiar 

 in his earlier researches. The results of this study were 

 published by the Hayden Survey in 1873, under the title 

 "Contributions to the Extinct Vertebrate Fauna of the 

 Western Territories. ' ' This was the last of Leidy's 

 major works, but he continued up to the time of his death 

 to report to the Academy concerning the various fossil 

 forms that were submitted to him for identification. Of 

 such reports the most important was one on the fossils 

 of the phosphate beds of South Carolina, published in 

 the Journal of the Academy in 1887. 



As a paleontologist, Leidy ranks with Cope and 

 Marsh high among those who enriched the American lit- 

 erature of the subject, but it must be remembered that 

 this was but a single aspect of his many-sided scientific 

 career, for he made many contributions of high order to 

 botany, zoology, and general and comparative anatomy 

 as well, nor did his knowledge and usefulness as an 

 instructor of his fellow men keep within the limitations of 

 these subjects. 



Othniel Charles Marsh (1831-1899). 



The sixth decade of the nineteenth century saw the 

 beginning of the labors of several paleontologists who, 

 like Leidy, were destined to raise the science of fossil 

 vertebrates in America to the level of attainment of the 

 Old World. They were, among others, Othniel Charles 

 Marsh and Edward Drinker Cope. Of these the names 

 of Marsh and Cope are linked together by the brilliance 

 of their attainments, their contemporaneity, and the 

 rivalry which the similarity of their pursuits unfortu- 

 nately engendered. Marsh produced his first paleon- 



