208 PICTURESQUE SKETCHES 



bility of other quadrupedal associates. The animals 

 in question were no doubt insectivorous ; and, as the 

 remains of insects have been frequently obtained from 

 the same beds, this is a point of some interest. It 

 was certainly the case that a group of animals, the 

 undoubted representatives of the highest class of 

 created beings, was introduced into the world before 

 or during this oolitic period, and it would be strange 

 if such group, having been introduced, remained un- 

 important or actually disappeared. But judging only 

 from the negative evidence before us, something of 

 this kind must be assumed, since there is subsequently 

 frequent and distinct proof of the near presence of 

 land, without any mammalian remains. It should 

 not be forgotten, indeed, that of all animal remains, 

 those of small quadrupeds inhabiting islands in a wide 

 ocean, are the most likely to be lost, and that, in a 

 case like this, negative evidence is really of very 

 little value. 



The bones of true birds have not yet been found 

 in any formation older than the chalk, but we have 

 already seen that there is good reason to believe in 

 the existence of such animals at least as early as the 

 new red sandstone, the footmarks in beds of that age 

 both in America and England affording evidence to 

 this effect. Now, if birds existed during the new 

 red sandstone period, it is most likely that they also 

 were continued from that time without interruption. 

 With regard to this subject, it must, however, be 

 acknowledged as one on which it is easy to specu- 

 late, but on which speculations are nearly useless. 



There is nothing in the distribution of the fossils 

 which entitles us to assume the total completion of 



