maesh.J DRYPTOSAURID.E. 203 



PART III. 

 CRETACEOUS DINOSAURS. 



During Cretaceous time in North America the dinosaurs were still 

 abundant, and most of them were much more specialized than those 

 that lived in the preceding periods. Some of the Cretaceous forms 

 were the strangest of the whole group, of gigantic size and bizarre 

 appearance. Others were diminutive in size and so bird-like in form 

 and structure that their remains can be distinguished with difficulty, 

 if at all, from those of birds. 



Of the carnivorous dinosaurs known from Cretaceous deposits the 

 family Dryptosauridse is especially conspicuous, on account of the large 

 size and ferocious nature of all its representatives. In the later Creta- 

 ceous a second family, the Ornithomimidse, was also abundant, and 

 among its members were some of the most minute and bird-like of 

 dinosaurs hitherto discovered. Of the herbivorous forms the huge, 

 horned Ceratopsidav, the most remarkable of all dinosaurs, were for a 

 limited period the dominant reptiles in western North America. Liv- 

 ing at the same time with these were the Olaosauridfe, large bipedal 

 dinosaurs, of sluggish disposition, that dwelt along the shores of the 

 lakes and rivers of that time. Besides these were still others related 

 to the Jurassic Stegosaurus, among them the Nodosauridae, quadrupedal 

 forms with heavy dermal armor. All these became extinct at the close 

 of the Cretaceous, and no remains of dinosaurs have been found in 

 place in any later deposits. 



THEROPODA. 

 DRYPTOSA URIDJi. 



This family is well represented throughout the Cretaceous in "North 

 America, but up to the present time only fragmentary remains have 

 been found, so that little is known about the skull, pelvis, and feet, the 

 most characteristic portions of the skeleton. So far as now determined 

 they appear to be nearly allied to Megalosaurus of Europe and include 

 Allosaurus from the Jurassic of this country. 



Remains of the genus Dryptosaurus (Lselaps) have been found at 

 various localities on the Atlantic Coast, especially in the marl region of 

 New Jersey. Many of these fossils have been described by Prof. Cope. 1 



ORNITHOMIMIDM. 



This family can be separated sharply from all other dinosaurs by the 

 hind feet, which contain three functional metatarsals, the middle one, or 

 third, of which has its proximal end much diminished in size and crowded 

 backward behind the second and fourth, as in many existing birds. 



1 Extinct Batrachia, Reptilia, and Avea of North America, p. 100, 1870. 



