302 LEADING AMERICAN MEN OF SCIENCE 



outgrowth . . . Professor Marsh gave an example of his excep- 

 tional shrewdness in working from fragmentary material. As 

 seen in [the] Plate, there remains only the basal portion of the 

 great crest once borne by the type skull. From the evidence offered 

 by this he was able to anticipate later discovery by figuring and 

 describing an enormous crest that formed about one-third the 

 entire length of the skull." It was during recent researches on 

 these pterodactyls that the "enormous crest" mentioned in the 

 quotation was disclosed in the matrix. The previous conjectural 

 restoration of this part of the skull by Marsh is of interest in con- 

 nection with a remark often made by him to one of his graduate 

 students: "Young man," he would say, "remember that we don't 

 any of us know much about this business." 



The Cretaceous chalks of western Kansas further yielded 

 remains of numerous sea-serpents, described by Marsh in a series 

 of papers also beginning in 1871. Mosasaurs, though compara- 

 tively rare in other parts of the world, were remarkably developed 

 in eastern and western sections of the United States. Marsh 

 cleared up many obscure points in the structure of these marine 

 reptiles, and was the first to determine some of the essential 

 characters of the skeleton. New genera and species of other types 

 of swimming reptiles were established by him, among which were 

 a few forms allied to Ichthyosaurus. 



Although Marsh's toothed birds and toothless pterodactyls, 

 together with his fossil horses, may seem to constitute the more 

 brilliant of his discoveries, yet probably the vertebrates that have 

 added most to his fame are those comprised in the reptilian group 

 called Dinosauria. Beginning in 1877, the notable discoveries 

 of these monsters of antiquity in both Jurassic and Cretaceous 

 deposits of the West, and later in the Triassic of the Connecticut 

 Valley; the description and illustration of various suborders, 

 families, genera, and species and the portrayal of their many pe- 

 culiar characters were brought out in numerous papers contributed 

 to the American Journal of Science, fourteen of which were re- 

 printed in the Geological Magazine of London. In the Dinosaurs 

 of North America, his third notable volume, which appeared in 



