THE DRAGONS OF OLD TIME DINOSAURS. 71 



Morosaurus, another important genus, is known from a large 

 number of individuals discovered in the now famous Atlantosaurus 

 beds of Colorado, including one nearly complete skeleton. The 

 head of this creature was small ; the neck elongated ; and the 

 vertebrae of the neck are lightened by deep cavities in their centra, 

 similar to those in birds of flight. The tail, also, was long. When 

 alive, this Dinosaur was about forty feet in length. It probably 

 walked on all fours ; and in many other respects was very unlike 

 a typical Dinosaur. The brain was small, and it must have been 

 sluggish in all its movements. The nearly complete remains of 

 Morosaurus grandis were found together in a very good state of 

 preservation in Wyoming, and many of the bones lay just in 

 their natural positions. 



Diplodocus, of which several incomplete specimens have been 

 discovered, was intermediate in size between Atlantosaurus and 

 Morosaurus, and may have reached when living, a length of forty 

 or fifty feet. Its skull was of moderate size, with slender jaws. 

 The teeth were weaker than those of any other known Dinosaur, 

 and entirely confined to the front of the jaws. Professor Marsh 

 concludes from the teeth that Diplodocus was herbivorous, feeding 

 on succulent vegetation, and that it probably led an aquatic life. 

 Fig. ii shows its skull. 



The remains of this interesting Dinosaur (Brontosaurus), which 

 in several ways differs from other members of the " lizard-footed " 

 group, were found in Upper Jurassic beds, near Canon City, Colo- 

 rado. A second smaller species was also discovered near Morrison, 

 Colorado. All the remains lay in the Atlantosaurus beds. These 

 strata the tomb in which Nature has buried up so many of her 

 dragons of old time can be traced for several hundred miles on 

 the flanks of the Rocky Mountains, and are always to be known 

 by the bones they contain. They lie above the Triassic strata 

 and just below the Sandstone of the Dakota group. Some have 

 regarded them as of Cretaceous age; but, judging from their 

 fossils, there can be but little doubt that they were deposited 



