HISTORY OF DISCOVERY 



CERATOPSTA REMAINS DISCOVERED IN COLORADO BY PROF. E. D. COPE. 



The next discovery of remains now known to pertain to the Ceratopsia was by Cope. a 

 The remains described by him as Polyonax mortuarius undoubtedly pertain to a member of 

 the Ceratopsia, and those parts referred provisionally to the ischia are certainly fragments of 

 frontal horn cores of one of the larger members of this group of dinosaurs. This material was 

 discovered by Cope during the summer of 1873 in Colorado (no more definite locality being 

 given) while he was working under the auspices of the United States Geological and Geographical 

 Survey. The remains are now in the American Museum of Natural History, New York, and 

 consist of portions of horn cores and limb bones in an extremely fragmentary condition. 



DISCOVERIES BY DR. G. M. DAWSON IN CANADA. 



It is also quite possible that some of the dinosaurian remains collected by Dr. G. M. 

 Dawson on Milk River, British America, in the early seventies of the past century, pertained 

 to the Ceratopsia, notwithstanding that all of these remains were referred by Cope to Hadro- 

 saurusfi A figure of a caudal vertebra from this collection, given by Cope in PI. VIII, figs. 9, 

 9a, of the volume just cited, appears to pertain to a member of the Trachodontidae. 



EXPLORATIONS IN JUDITH RIVER BEDS BY PROFESSOR COPE. 



In 1876 Cope undertook an exploration of the Judith River badlands of the upper Missouri 

 River. On this expedition he was assisted by Messrs. Charles H. Sternberg and John C. 

 Isaac. The expedition was especially successful in securing reptilian 

 remains, including a considerable number of Dinosauria belonging 

 to several new genera and species. Among these were remains of 

 several species of which, on account of the fragmentary condition of 

 the material, Cope was at that time unable to determine the nature, 

 but which are now known to pertain to the Ceratopsia. The first 

 notice of this material appeared in the Proceedings of the Philadel- 

 phia Academy of Natural Sciences for 1876, e pages 248 to 261, and 

 on pages 255-256 the genus and species Monoclonius crassus are 

 briefly described from material belonging partly to the Trachodontidae 

 and partly to the Ceratopsidae. From the description given by Cope 

 it is evident that the skeletal material pertains to the Ceratopsia, 

 while the teeth are those of Trachodon. Of the skull only the parie- 

 tals are mentioned, and they are described as the episternum. 



The following year, 1877/ Cope described and figured the supra- 

 orbital horn core and occipital region shown here respectively in figs. 

 3 and 4. Although Cope was at that time unable to determine the homology of the part shown 

 here in fig. 3 or to refer either bone with certainty to any known dinosaur, we now know that 

 they both pertain to Monoclonius or a closely allied genus. They likewise were from the Judith 

 River beds and were found by Professor Cope in 1876 associated with other bones on the north 

 side of the Missouri River, opposite the mouth of Dog Creek. 



Thirteen years later, 6 after Professor Marsh had made known the principal characters of 

 the skull in these dinosaurs from the abundant material collected by me in Wyoming and 

 Montana, Cope was able to determine with accuracy the nature of his material, and he then 

 briefly described three additional species from his Judith River collections and referred them to 

 the genus Monoclonius. These were M. recurvicornis, M. sphenocerus, and M.jissus. Figures of 



a Report on the vertebrate paleontology of Colorado: Ann. Rept. TJ. S. Geol. and Geog. Surv. Terr, for 1873 (pub. 1875) , pp. 429-533. 

 b Cretaceous Vertebrata: Rept. XT. S. Geol. and Geog. Surv. Terr., vol. 2, 1875, p. 56. 



c Descriptions of some vertebrate remains from the Fort Union beds of Montana: rroe. Acad. Nat. Sci. Phila., 1876, pp. 248-261. 

 d Report on the geology of the region of the Judith River, Montana, and on vertebrate fossils obtained on or near the Missouri River: Bull. 

 TJ. S. Geol. and Geog. Surv. Terr., vol. 3, pp. 565-597. pis. 30-34. 



« The horned Dinosauria of the Laramie: Am. Naturalist, 1889, pp. 715-717. 



Fig. 3. — Postfrontal, with supra- 

 orbital horn core, of Monoclonius 

 recurvicornis. Figured but un- 

 identified by Cope in 1877. A, 

 Superior view; B, lateral view. 

 One-fourth natural size. After 

 Cope. 



