208 THE STORY OP THE EARTH AND MAN. 



our modern days, while tlie birds were compelled to 

 assume some reptilian traits. 



Yet, strange to say, representatives of tlie liiglier 

 creatures destined to inherit the earth at a later date 

 actually existed. Toward the close of the Mesozoic 

 we find birds approaching to those of our own day, 

 and almost at the beginning of the time there were 

 small mammals, remains of which are found both in 

 the earlier and later formations of the Mesozoic, but 

 which never seem to have thriven; at least so far as 

 the introduction of large and important species is 

 concerned. Traversing the Mesozoic woods, we might 

 see here and there little hairy creatures, which would 

 strike a naturalist as allies of the modern bandicoots, 

 kangaroo rats, and myrmecobius of Australia; and 

 closer study would confirm this impression, though 

 showing differences of detail. In their teeth, their 

 size, and general form, and probably in their pouched 

 or marsupial reproduction, these animals were early 

 representatives of the smaller quadrupeds of the 

 Austral continent, creatures which are not only small 

 but of low organisation in their class. 



One of these mammals, known to us only by its 

 teeth, and well named MicrolesteSy the ^'^ little thief,'' 

 sneaks into existence, so to speak, in the Trias of 

 Europe, while another very similar, Dromatherium, 

 appears in rocks of similar age in America ; and this 

 is the small beginning of the great class Mammalia, 

 destined in its quadrupedal forms to culminate in the 

 elephants and their contemporaries in the Tertiary 



