On a Gigantic Saurian from the Dakota epoch of Colorado. 

 By E. D. Cope. 



Not long since I was informed by the Superintendent of Public Scbools 

 of Fremont County, Colorado. Mr. O. W. Lucas, that he had discovered 

 the bones of an enormous saurian at an outcrop of the rocks of the Dakota 

 group, not far from Canyon City. I encouraged him to proceed with the 

 exploration, and asked him to send some specimens which should explain 

 the character of his discovery One of the first objects sent is a fragmentary 

 lower jaw of a carnivorous dinosaurian, which he found on the surface of 

 the ground. This fossil was found to belong to a species heretofore un- 

 known, which I referred to the genus Lcelaps under the name of Lcelaps 

 trihedrodon* The second sending included a number of vertebrae, which 

 apparently represent a much more gigantic animal, and I believe the 

 largest or most bulky animal capable of progression on land, of which we 

 have any account. 



The vertebra? comprise a cervical, three dorsal and four caudal vertebrae. 

 The dimensions of the animal to which they belonged may be inferred from 

 the fact that the first is twenty inches in length, and twelve in transverse 

 diameter ; and that one of the dorsals measures three and a half feet in the 

 spread of its cliapophyses, two and a half feet in elevation, and the centrum 

 thirteen inches in transverse diameter. Another dorsal is two feet ten 

 inches in elevation. 



The centra of these vertebrae have a ball and socket articulation of the 

 opisthocoelian type, the cups and balls being well pronounced. Just be- 

 neath the diapophysis is situated a huge foramen. A broken centrum from 

 which Mr. Lucas removed the matrix, shows that this foramen communi- 

 cates with a huge internal sinus, which occupies almost the entire half of 

 the body of the vertebra. Those of opposite sides are separated by a sep- 

 tum which is thin medially. Thus the centra of the dorsals are hollow. 

 The neural arches are remarkable for their great elevation, and the great 

 expanse of the zygapophyses. They are more remarkable for the form of 

 the neural spines, which are transverse to the long axis of the centrum. 

 That of one of the vertebrae is strongly emarginate so as to be bifurcate. 

 The widely extended cliapophyses support the rib-articulations, and there 

 are no capitular articular facets on the centra, but such are found on the 

 basal region of the cliapophyses in some vertebrae. 



The supposed cervical vertebra is depressed, the anterior or convex ex- 

 tremity of the centrum the most so. It is remarkable for its elongate form 

 exceeding the proportions found in known Dinosauria and Crocodilia, and 

 resembling that seen in some fiuviatile tortoises. Near the anterior ex- 

 tremity a short, robust parapophysis has its origin, from which it extends 

 outwards and downwards, and soon terminates in a truncate extremity 

 which presents downwards. A deep fossa occupies its upper base, and above 



* Bullet. IT. S. Geol. Surv. Terrs. Ill, 1877. 



