104 THE CEEATOPSIA. 



The following year Marsh recognized the true affinities of this species and placed it in the 

 genus Ceratops. His remarks at this time were as follows: 



The specimen recently described by the writer under the name Hadrosaurus paucidens should probably be referred to the 

 genus Ceratops, as a comparison with more perfect specimens indicates a much closer affinity with that genus than at first 

 supposed. In addition to the maxillary described, one of the premaxillaries is in good preservation. This agrees in general 

 features with the corresponding bone in Triceratops, but is less specialized. Its inner surface is deeply concave, showing that 

 the two premaxillaries did not meet each other closely, as in Triceratops, but apparently only in front. This species, as well 

 as the. type of the genus Ceratops montanus, represents smaller, less specialized forms of the family, and may be from a lower 

 geological horizon than the gigantic reptiles which the. writer has recently made known. 



It is not at all unlikely that the type of the present species pertained to one of the several 

 species of Ceratopsidas already described as from the Judith River beds. Since, however, the 

 teeth, the maxillaries, and the premaxillaries of all these are imperfectly known, it is at present 

 impossible to determine to which of them this specimen should be referred. Marsh's statement 

 that this, species, as well as the type of the genus Ceratops montanus, represents smaller, less 

 specialized forms, from a possibly lower geological horizon than the gigantic Ceratopsidas from 

 the Laramie of Converse County, Wyo., is significant, considering that the present type was 

 recovered from near the summit of the Judith River beds, and should be taken as additional 

 evidence in favor of the view long held by the present author, that the Judith River beds repre- 

 sent a horizon decidedly older than the beds of Converse County, Wyo., the correctness of 

 which was conclusively demonstrated in 1903 by the stratigraphic work of Messrs. T. W. 

 Stanton and J. B. Hatcher. 6 



SPECIES ERRONEOUSLY REFERRED TO CERATOPS. 



The two species Ceratops (Bison) alticornis and C. Jiorridus, although originally referred by 

 Marsh to Ceratops, certainly do not pertain to that genus. Their affinities are more nearly with 

 Triceratops, in which genus the latter was subsequently placed by Professor Marsh, though for 

 some reason unknown to the present writer, or perhaps by oversight, the former was left by 

 Marsh in the genus Ceratops. In the present volume they will be considered as belonging to the 

 genus Triceratops, and their description will be deferred until we come to treat of the species 

 of that genus. 



From the above description of these earlier, smaller, and more primitive forms from the 

 Judith River beds we will pass on to the larger, later, and more specialized forms from the 

 Laramie of southern Wyoming and of Converse County in east-central Wyoming, from north- 

 western South Dakota, eastern Montana, and from the possibly later deposits, known as the 

 Denver beds, of Colorado. 



REVIEW OF THE SPECIES OF LAEAMIE CERATOPSIA. 



GENERA AND SPECIES DESCRIBED BY PROFESSOR COPE. 



AGATHAUMAS Cope. 



Type species is A. sylvestris. 



Original description of genus, Proc. Am. Philos. Soc, vol. 12, pp. 481-483. 

 Baur, G., Science, vol. 17, 1891, pp. 216-217; Am. Naturalist, vol. 25, 1891, pp. 448, 450, 452. 

 Cope, Ann. Rept. U. S. Geol. and Geog. Surv. Terr, for 1873, pp. 435, 438, 442, 444-446; Bull. U. S. Geol. and Geog. Surv. 



Terr., vol. 1, No. 2, 1st ser., pp. 16, 17; Rept. U. S. Geol. and Geog. Surv. Terr., vol. 2, 1875, pp. 41, 53-54, 248; Am. 



Naturalist, vol. 12, 1878, p. 246; Proc. Acad. Nat. Sci. Phil, 1883, p. 99; Am. Naturalist, vol. 23, 1889, p. 715; Syl. 



Lectures on Pal., Univ. of Pennsylvania, 1891, p. 43; Am. Naturalist, vol. 26, 1892, pp. 757-758. 

 Dana, J. D., Manual of Geology, 1895, p. 847. 

 Editor Am. Geologist, Am. Geologist, vol. 8, 1891, p. 56.. 

 Lydekker, R., Nature, vol. 48, 1893, p. 304. 

 Lambe, L. M., Sum. Rept. Geol. Surv. Canada, 189S, p. 187. 

 Marsh, O. C, Am. Jour. Sci., 3d ser., vol. 41, Feb., 1891, p. 176; vol. 43, Jan., 1892, pp. S3 and 84; vol. 50, Dec, 1895, 



p. 497; Sixteenth Ann. Rept. U. S. Geol. Survey, 1896, pt. 1, pp. 217, 243. 

 Nopcsa, F. Baron, Foldtani Kozlony, vol. 31, Budapest, 1901, p. 270. 



" Am. Jour. Sci., vol. 39, 1890, p. 83. b Bull. U. S. Geol. Survey No. 257, 1905. 



