8 THE CEEATOPSIA. 



embedded in a hard sandstone concretion, weighing not less than 2,000 pounds, that lay in the 

 bottom of a deep canyon about 35 miles north of Lusk, Wyo. Observing my interest in the 

 specimen, Mr. Guernsey very kindly assured me that if I wished to see the skull he would at 

 some future time conduct me to the locality, from the immediate fulfillment of which favor 

 he was then prohibited by pressing business engagements. 



Having completed my season's work in the White River badlands, I returned to New 

 Haven on January 3, 1889. In the meantime I had written Professor Marsh several letters 

 concerning this peculiar horn core and he had published, in December, 1888, his description 

 of Ceratops montanus, from the material which I had collected in the early part of the season 

 in Montana and which for the first time demonstrated the presence of horned dinosaurs in the 

 Judith River beds. This, together with the fact that Cannon, Eldridge, and Cross had already 

 recovered undoubted dinosaur remains from the Denver beds, where the type of Bison alticornis 

 had been found in situ, caused Professor Marsh to doubt the mammalian nature of the pair of 

 horn cores which constituted the type of the latter and of which I had as yet only seen figures. 

 When I examined these horn cores, soon after my arrival in New Haven, I at once recognized 

 the striking similarity between them and the horn core in the collection of Mr. Guernsey. I 

 also expressed an opinion that the latter could have come only from Upper Cretaceous beds. 

 I immediately wrote Mr. Guernsey requesting him to send on his specimens for further exam- 

 ination and comparison. He very kindly and promptly complied with this request, and on its 

 arrival in New Haven Professor Marsh at once recognized the remarkable similarity between 

 the two specimens, and, after his characteristic nature, became immediately possessed with a 

 burning desire to secure the skull and learn the exact geological horizon from which it came. 

 Accordingly, on February 20, 1889, I left New Haven for Lusk, Wyoming, and although long 

 delayed by inclement weather, the season being midwinter, succeeded in securing the remainder 

 of the skull, our party having been conducted to the exact locality by Mr. Wilson, the original 

 discoverer of the specimen. The skull was found embedded in a large sandstone concretion at 

 the bottom of a deep canyon, exactly as had been described by Mr. Guernsey. 



The incidents connected with the procurement of this skull are here thus fully related for 

 the twofold purpose of giving full credit to all concerned and of illustrating the manner in which 

 one of the most important localities for vertebrate fossils was made known, for it was in this 

 immediate vicinity, in Converse County, Wyoming, that the remarkable collection of Ceratopsia 

 and the scarcely less remarkable collection of remains of other reptiles, as well as several 

 thousand isolated jaws and teeth of diminutive mammals, were procured by me and my 

 assistants, Messrs. Peterson, Utterback, and Sullins, during the years 1889-1892, while working 

 in the interests of the United States Geological Survey and under the direction of Prof. O. C. 

 Marsh. As the work of exploration in this newly discovered locality progressed the exact 

 nature of this remarkable group of dinosaurs was rapidly brought to light and the real affinities 

 of those remains, which had for a long time proved so puzzling to both Cope and Marsh, became 

 apparent. The supposed ischia of Polyonax mortuarius, described and figured by Cope, were 

 seen to be portions of the supraorbital horn cores, while the element considered by the same 

 author as an episternal of Monoclonius crassus proved to be a parietal. The horn cores described 

 by Marsh as pertaining to a bison proved to belong to a dinosaur, and the supposed dermal 

 plates mentioned by him in his description of the type of Ceratops montanus became the squa- 

 mosals of that animal. Nor should these errors in identification be taken as a reflection upon 

 the sagacity of either of these authors, but rather as additional evidence of the remarkable 

 nature of these newly discovered dinosaurs, so different in so many osteological characters 

 from anything hitherto discovered or suspected among representatives of that group. They 

 are, however, striking examples of the many pitfalls that beset the path of the paleontologist 

 when attempting to describe from insufficient or fragmentary material new genera and species — 

 and especially new families — of extinct animals. They are, moreover, striking examples of 

 that axiom so often disregarded in vertebrate paleontology, namely, that one observed fact is 

 worth any amount of expert opinion. 



