90 ANIMALS OF THE PAST 



so far back of the junction of head with neck as to 

 largely counterbalance the weight of the face and jaws. 

 When we restored the skull of this animal it was found 

 that the centre of gravity lay back of the eye. Several 

 of the bones of the neck are united in one mass to furnish 

 a firm attachment for the muscles that support and 

 move the skull, but as the movements of the neck are 

 already restricted by the overhanging frill, this loss of 

 motion is no additional disadvantage. 



To support all this weight of skull and body requires 

 very massive legs, and as the fore legs are very short, 

 this enables Triceratops to browse comfortably from 

 the ground by merely lowering the front of the head. 



These forms we have been considering were the giants 

 of the group, but a commoner species, Trachodon, 

 though less in bulk than those just mentioned, was still 

 of goodly proportions, for, as he stalked about, the top 

 of his head was twelve feet from the ground. 



Trachodon and his kin seem to have been abundant, 

 for they have a wide distribution, and many specimens, 

 some almost perfect, have been discovered in this 

 country and abroad. We might say that so far as 

 North America was concerned they were during the 

 Cretaceous period what deer are to-day, the most com- 

 mon and characteristic of herbivores. No less than 

 twenty-nine Iguanodons, a European relative of 

 Trachodon, were found in one spot in mining for coal at 

 Bernissart, Belgium. Here, during long years of Creta- 

 ceous time, a river slowly cut its way through the coal- 

 bearing strata to a depth of 750 feet, a depth almost 

 twice as great as the deepest part of the gorge of 

 Niagara, and then, this being accomplished, began the 

 work of filling up the valley it had excavated. It was 

 then a sluggish stream with marshy borders, a stream 

 subject to frequent floods, when the water, turbid with 



