148 EXTINCT MONSTERS 
localities where the animal had evidently become mired, just as 
cattle at the present day sometimes become hopelessly fixed in a 
swampy place on the margin of a lake or river (see p. 19). Each 
track made by the creature in walking occupied one square yard 
in extent ! 
The Sauropoda, or lizard-footed Dinosaurs, show in many ways 
a decided approach to a simple or generalised crocodile ; so much 
so, that Professor Cope is inclined to include crocodiles and sauro- 
podous Dinosaurs in the same order. Vertebree, limb-bones, 
skulls, and teeth have all been discovered through the zeal and 
energy of Professor Marsh and his comrades, in the far west of 
America, as well as by the researches of English geologists, assisted 
by the labours of many ardent collectors of fossils, in this country. 
Some of these may now be briefly considered. 
In Plate XVIII. we have endeavoured to give some idea of a 
huge thigh-bone (femur) belonging to the truly gigantic Dinosaur 
called Atlantosaurus. It is six feet two inches long, and a cast 
of it may be seen in the fossil reptile gallery of the British 
Museum of Natural History. It should be mentioned, however, 
that the original specimen is partly restored, so that its exact 
length to an inch or so is not quite certain. In our illustration 
it is shown to be a little taller, when placed upright, than a full- 
grown man. Professor Marsh, the fortunate discoverer of this 
wonderful bone, calculates that the Atlantosaurus must have 
attained a length of over eighty feet! and, assuming that it 
walked upon its hind feet, a height of thirty feet! 
It doubtless fed upon the luxuriant foliage of the sub-tropical 
forests, portions of which are preserved with its remains. Besides 
this thigh-bone, Professor Marsh has procured specimens of 
vertebree from the different parts of the vertebral column; but no 
skull or teeth. The vertebre are hollowed out much in the same 
