DRAGONS OF OLD TIME 151 
water, and could use its powerful tail in swimming, we may 
perhaps find a way out of the difficulty by supposing that, when 
alarmed by dangerous flesh-eating foes, it took to the water, and 
found discretion to be the better part of valour. Although 
apparently stupid, the Brontosaur probably possessed a good deal 
of cunning, and we can fancy it stretching its long neck above 
reeds, ferns, and cycads to get a view of the approaching 
enemy. 
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, 
Colorado. 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 during the Jurassic period — probably in an old 
estuary. They consist of shale and sandstone. 
Besides the numerous Dinosaurs, Professor Marsh’s colleagues 
have found abundant remains of crocodiles, tortoises, and fishes, 
with one Pterodactyl, a flying reptile (see Chap. XI.), and several 
small marsupials. The wonderful collection of American Jurassic 
Dinosaurs in the Museum of Yale College includes the remains 
of several hundred individuals, many of them in excellent pre- 
servation, and has afforded to Professor Marsh the material for 
his classification already alluded to. 
For a good many years past the State of Wyoming has been 
