108 EXTINCT MONSTERS. 
why should they not have been able to go a few steps further, 
and actually decome mammals?” The Evolutionist, if confronted 
with such a question, would say, that there is no evidence of 
Dinosaurs turning into mammals, but that both may have branched 
off at an early geological period (say the Permian) from a 
primitive group of reptiles, or even of amphibians. 
It must be borne in mind that, during the “‘age of reptiles” 
(Mesozoic period), the mammalian type was but feebly represented 
by certain small and humble forms, probably marsupials. As far 
as we know, there were no big quadrupeds such as flourish to-day ; 
therefore reptiles played their part, and in so doing acquired some 
of their habits and structural peculiarities. It is difficult for us, 
living in an age of quadrupeds, to realise this, and to picture to 
ourselves reptilian types posing as “lords of creation,” or, to use 
a homely phrase, “strutting in peacock’s feathers.” 
Leaving now the English herbivorous Dinosaurs, we pass on to 
those still more wonderful forms discovered of late years by Pro- 
fessor Marsh. The former have been treated at considerable 
length, first because they are English, and, as such, the history of 
their discovery possesses considerable interest ; secondly, because 
their elucidation reflects the highest credit on our great pioneers 
in this fruitful field of research, and illustrates the manner in 
which great naturalists have been able to draw most important 
and wonderful conclusions (afterwards verified in most cases) from 
material apparently far from promising. For example, Cuvier’s 
prophecy of the Iguanodon from a few teeth is a striking example 
of the result of reasoning from the known to the unknown, an 
example which seems to us worthy to be ranked with the 
discovery of Neptune by Adams and Leverrier, or, to take a more 
recent case, the discovery by Mendeleef of the Periodic Law, by 
means of which he has foretold the discovery of new chemical 
elements. 
Whatever may have been the origin of the great mammalian 
