416 Othniel Charles Marsh. 



to refer them to the Jurassic, a formation which had been con- 

 sidered as absent in eastern North America. 



There yet remains for consideration the real work of his 

 life, — his publications on the Fossil Vertebrates, and it is at 

 once evident, from a glance at the bibliography, that his chief 

 researches were upon the Reptiles, Birds, and Mammals. 

 There are three papers on Fossil Fishes, containing notices of 

 several new forms, but no real research in this class was ever 

 undertaken by him. The Amphibians also claimed but little 

 attention, and his observations on the metamorphosis of the 

 recent Siredon into Ambly stoma, and two brief notices of 

 amphibian footprints in the Devonian and Carboniferous, com- 

 prise the whole. 



It is with extreme hesitation and a sense of inadequacy that 

 the writer ventures to review, even in the briefest and most 

 superficial manner, the work which undoubtedly constitutes 

 the literary essence of his life-work. Future investigators 

 alone can critically estimate the great mass of facts which 

 Marsh brought out and which he wove into the departments 

 of fossil Reptiles, Birds, and Mammals. 



His most comprehensive work, and in many ways the most 

 masterly, is the address delivered before the American Asso- 

 ciation for the Advancement of Science, at Nashville, in 1877. 

 In this paper, entitled the "Introduction and Succession of 

 Vertebrate Life in America," he traced the introduction of the 

 various types of vertebrate life then known in America, begin- 

 ning with the lowest fishes and ending with man. The amount 

 of knowledge on the lower classes of vertebrates, including the 

 reptiles, was then too meager to, enable him to give more than 

 occasional hints as to their phylogeny. But his handling of 

 the Mammalia showed the clearest insight into the develop- 

 ment and affinities of many of the important types, and marked 

 him as a true philosopher. 



A glance at the modern text-books of Geology and Paleon- 

 tology reveals how much America has done for the fossil ver- 

 tebrates in the three classes of Reptiles, Birds, and Mammals. 

 It will also show that Marsh contributed more than any other 

 investigator toward the prominence now accorded to the 

 American forms. 



