NATURAL HISTORY OF CREATION. 89 



to have formed a link lietween the pk^siosaurus and the 

 crocodile. We know of at least six species of the flying 

 saurian, the pterodactyle, in this formation. 



Now, for the first time, we find remains of insects, an 

 order of animals not well calculated for fossil preservation, 

 and which are therefore amongst the rarest of the animal 

 tribes found in rocks, though they are the most numerous 

 of all living families. A single libellula (dragon-fly) was 

 found in tlio Stonesfield slate, a member of the lower 

 oolitic group quarried near Oxford ; and this was for 

 several years the only specimen known to exist so eai-ly ; 

 but now many species have been found in a corresponding 

 rock at Solenhofen in Germany. It is remarkable that 

 the remains of insects are found most plentifully near 

 the remains of pterodactyles, to which undoubtedly they 

 served as pre}-. 



The first glimpse of the highest class of the vertebrate 

 sub-kingdom — mcuiimaVia — is obtained from the Stones- 

 field slate, where there have been found several specimens 

 of the lower jaw-bone of a quadruped evidently insecti- 

 vorous, and inferred, from peculiarities of structure, 

 to have belonged to the marsupial family (pouched 

 animals).* It may be observed, although no specimens 

 of so high a class of animals as mammalia are found 

 earlier, such may nevertheless have existed : the defect 

 may be in our not having found them ; but other things 

 considered, the probability is that heretofore there were 

 no mammifers. It is an interesting circumstance that 

 the first mammifers found should have belonged to the 

 marsupialia, when the place of that order in the scale of 

 creation is considered. In the imperfect structure of 



* Fragments attributed to a cetaceous animal, another humble 

 form of the mammal class, have likewise been found in the great oolite, 

 near Oxford. 



