248 Frof. 0. C. Marsh — Restoration of Triceratops. 



which offers other points of resemblance in its skull and skeleton. 

 These features, however, indicate only a very remote affinity, and 

 it is among the Dinosaurs alone that this group can be placed, as a 

 distinct family, in the order Ornithopoda. 



The CeratopsidcB resemble, in various points, the Stegosauria of 

 the Jurassic, especially in the vertebrae, limbs, and feet. The 

 greatest difference is seen in the skull, but the pelvic arch, also, 

 shows a wide divergence. In the Geratopsidce, there is no marked 

 enlargement of the spinal cavity in the sacrum, and there is no 

 post-pubis. 



The characters above given are based upon fossils which I have 

 personally investigated, including the type specimens of Ceratops 

 and Triceratops, on which, mainly, the family Geratopsidce was 

 established. The material now at my command includes the 

 remains of many individuals, among which are portions of about 

 twenty different skulls, and some of these are nearly perfect. In 

 the memoir now in preparation, I shall fully describe and illustrate 

 all the more important of these specimens, and likewise discuss their 

 relations to allied forms. 



The generic names, AgatTiaumas, Cratmomus, Monoclonius, and 

 one or two others, have been given to fragmentary fossils, which 

 may belong to this group, but these remains, so far as made known, 

 appear quite distinct from those here described. 



In conclusion, let me say a word as to how the discoveries here 

 recorded have been accomplished. The main credit for the work 

 justly belongs to my able assistant, Mr. J. B. Hatcher, who has 

 done so much to bring to light the ancient life of the Eocky 

 Mountain region. I can only claim to have shared a few of the 

 dangers and hardships with him, but without his skill and energy, 

 little would have been accomplished. If it is borne in mind that 

 two of the skulls weighed nearly two tons each, when partially 

 freed from their matrix, and ready for shipment, in a deep, desert 

 caiion, fifty miles from a railway, you will appreciate one of the 

 mechanical difficulties overcome. When I add that some of the 

 most interesting discoveries were made in the hunting grounds of 

 the hostile Sioux Indians, who regard such explorations with super- 

 stitious dread, you will understand another phase of the problem. 

 I might speak of even greater difficulties and dangers, but the 

 results attained repay all past efforts, and I hope at no distant day 

 to have something more of interest to lay before your readers. 



11. — Appendix. — Eestoration of Tkicekatops. 



By Prof. 0. C. Marsh, Ph.D., LL.D., P.G.S., etc. 



(PLATE VII.) 



TN previous numbers of this Magazine, the writer has given the 

 principal characters of the gigantic Geratopsidce, or horned 

 Dinosaurs, from the Laramie, with figures of the more important 

 parts of the skull and skeleton.^ The abundant material now 



1 See Geol. Mag. 1890, January Number, pp. l-o, and Plate I. Geol. Mag. 

 1891, April Number, PL IV. May Number, PI. V. pp. 193-199, ante, pp. 241-248. 



