MESOZOIC TIME — CRETACEOUS. 



84^ 



1416. 



the beaked moutli of a Turtle, or rather of the Ehynchocephs of the Trias. 

 They are from the same Laramie beds in Wyoming that afforded the Clao- 

 saurus, and occur also in the Denver beds, near Denver, Col. (where the first 

 specimen was found), at Black Butte, Wyoming, and in the Judith River 

 beds, Montana. The restoration by Marsh (Fig. 1412), one sixtieth the 

 natural size, shows the general character of the skeleton of these strange 

 but stupid inhabitants of the waning Mesozoic. The broad cranium (over 

 eight feet long in one species) projects far over the neck, like the posterior 

 flap of some forms of helmet, and sometimes has a degree of decoration in 

 its pointed posterior margin. 



The teeth had two prongs (Fig. 1413), a Mammalian feature not known 

 in other Reptiles. The skull of another species of the genus is shown in 

 Fig. 1414 ; and of a third, but of a distinct genus, Torosaurus, in Fig. 1415. 

 J. B. Hatcher, who procured many of the bones described by Marsh, gives 

 evidence (1893) that the great Dinosaurs lived in the region where they 

 died ; and he speaks of one skeleton of Claosaurus annectens Marsh (Fig. 

 1408), as found in a partially erect condition, the limbs extended, the 

 ribs in natural position about the abdominal and thoracic cavities, and every 

 bone in its natural place, showing that the animal had been mired in the 

 quicksands. Some of the Ceratopsid skulls, 

 although seven to eight feet long, make the 

 centers of sandstone concretions, weighing many, 

 tons. 



Other genera of Ceratopsids described by 

 Cope are AgatJiaumas, Monodonius, and Polyo- 

 nax, severally from Wyoming, Montana, and 

 Colorado. Agathcmmas sylvestris is from the 

 Laramie of Black Butte station in southern 

 Wyoming, 



Carnivorous Dinosaurs were represented by a 

 number of species. Loelaps aquilunguis of Cope 

 (1869), from the Upper Greensand, New Jersey, 

 is about 24 feet long; it probably could stand 

 nearly erect. L. incrassatus is reported by him 

 from Montana, and also from the Laramie beds 

 of Red Deer River in British America. The 

 Oniithomimus of Marsh is a small species from 

 the Laramie Ceratops beds of Wyoming, remark- 

 ably bird-like in its skeleton, as illustrated in 

 the figure (Fig. 1416). It probably could stand 

 erect like a bird. 



The Mosasaurids, or Sea-serpents, of the era, 

 PytJionomorphs of Cope (after the genus Pytho), 



were eminently characteristic of the Upper Cretaceous. Previous to the 

 American discoveries of their remains, knowledge of them was confined 



1416 a. 



Dinosaur. — Fig-. 1416, Ornithomi- 

 mus velox, 2d, 3d, and 4th meta- 

 tarsals, natural size ; 1416 a, 

 phalanges of 2d digit. Marsh. 



