516 GEOLOGY OF THE DENVER BASIN. 



This restoration gives a correct idea of the general proportions of the 

 entire skeleton in the genus Triceratops. The size, in life, would be about 

 .25 feet in length and 10 feet in height. 



This specimen was found by J. B. Hatcher^in the Ceratops beds of 

 ( 'on verse County, Wyo. 



CLAOSAURUS. 



Another large herbivorous dinosaur, Claosaurus, has left its remains in 

 the same horizon as the gigantic Ceratopsidse, but owing to their smaller 

 size and more delicate proportions they are much less conspicuous, aud 

 hence appear to lie less abundant. The best-known species of the present 

 genus is Claosaurtis annectens, and a restoration of the type specimen will 

 be found on PI. XXVIII. This animal was bipedal in locomotion and had 

 very small anterior limbs. The head was comparatively large and the tail 

 long and massive. 



The skull of Claosaurus is long ami narrow, with the facial portion 

 especially produced. The anterior part is only moderately expanded trans- 

 versely. Seen from the side. li^'. SI (p. 517), the skull shows a blunt, rugose 

 muzzle, formed above by the premaxillary and below by the predentary, 

 both probably covered iii life with a thick, corneous integument. 



Behind the upper part of this muzzle is an enormous lateral cavity, 

 which includes the narial orifice, lint was evidently occupied in life mainly 

 I iv a nasal gland, somewhat like that in the existing Monitor, and also seen 

 in some birds. This cavity is bounded externally by the nasal bone and 

 the premaxillary. The median septum between the two narial orifices 

 was onlv in part ossified, the large oval opening now present in the skull 

 probably having been closed in life by cartilage. 



The orbit is very large and subtriangular in outline. It is formed 

 above by the prefrontal, frontal, and postfrontal, and below mainly bj^ the 

 jngal. There are no supraorbital bones. A distinct lachrymal forms a 

 portion of the anterior border. 



The lower jaws are long and massive. The predentary bone is robust 

 and especially iitted for meeting the strong beak above. The dentary 

 bones are large and powerful, with elevated coronoid processes. The 



