FOREWORD TO THE MONOGRAPHS ON VERTEBRATE PALEONTOLOGY. 



By Henry Fairfield Osborn. 



While vertebrate paleontologist of the United States Geological Survey Prof. Othniel 

 Charles Marsh originated the large conception of a series of paleontological monographs worthy 

 of the remarkable nature and preservation of the ancient life of North America. His plan was 

 to make very complete collections of certain orders and families of vertebrates, to illustrate them 

 in the most artistic manner, and to describe and discuss them in detail. At the time of his 

 death, in 1899, the execution of this great plan was left in the following condition. 



1. Odontornitkes Published in 1880. 



2. Dinocerata Published in 1884. 



3. Sauropoda. _ . Incomplete ; preliminary bulletins published. 



4. Ceratopsia. .Unpublished: preliminary bulletins published. 



5. Stegosauria Unpublished; preliminary bulletins published. 



6. Brontotheriidse Unpublished; preliminary bulletins published. 



In 1900 the Director of the United States Geological Survey invited me to take general 

 oversight of the preparation of the four incomplete monographs, and all the unpublished work 

 which had been prepared by my distinguished predecessor was put into my hands after revision 

 and report by a special committee. It was found to consist entirely of 204+ carefully prepared 

 lithographic plates, of drawings and wood engravings, some partial bibliographies, and about 

 100 pages of rough pencil notes and memoranda. The supervision and execution of these illus- 

 trations had involved years of labor. There was no manuscript whatever. All record of the 

 numerous and important observations which Professor Marsh had made of these groups of 

 animals he had already published in preliminary bulletins, chiefly in the American Journal of 

 Science and in his two contributions to the Survey publications, "The dinosaurs of North 

 America" (1896), and "Vertebrate fossils of the Denver Basin" (1897). 



The entire text of the four monographs therefore remained to be written. To treat 

 exhaustively the materials which had been collected under Professor Marsh's direction and to 

 cover the progress of the many succeeding years of exploration and research by other authors 

 constituted only a part of the work which remained to be done. Many new plates and sup- 

 plemental illustrations were evidently necessary. Geological as well as paleontological explor- 

 ation in the field was absolutely needful in order to supplement the very meager data which 

 had been preserved as to the geological conditions and stratigraphic distribution of these ani- 

 mals — data hardly less essential to their philosophical comprehension than the data afforded 

 by the fossils themselves. 



After very considerable thought I decided upon the following as the most desirable uniform 

 plan of treatment for each volume and each group : 



Section 1 . History of discovery and of the gradual development of knowledge of the struc- 

 ture and affinities of the group. 



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