j 





I 





/ 



Ph. IX.] 



AT SUCCESSIVE GEOLOGICAL PERIODS. 



1G5 



' 



man m 



bon, discovered in the South of France, r 

 stature. If in the Pliocene strata, which followed next 

 in the order of time, no quadrumana have been detected, 

 we may attribute their absence to the diminished warmth 

 of the Pliocene climate, which began to resemble that now 

 enjoyed in the south of Europe, instead of being, like that 

 of the Upper Miocene, sub-tropical. For evidence of the 

 gradual development of the monkeys, apes, and orangs, and 

 of the first appearance of man, the progressionist will natu- 

 rally look to those countries which escaped the rigours of 

 the Glacial Period, whereas our most careful investigations 

 have hitherto been confined to the temperate latitudes of 

 the northern hemisphere, whether in the Old or New World. 

 However slender therefore may be the foundation of facts 

 on which such grand generalisations are built, and however 

 anxious we may be not to place too much reliance on the 

 soundness of our inferences, we may yet say that the direction 

 in which the facts point are decidedly towards the theory of 



progression. 



We have been fairly led by paleontological researches to the 



conclusion that the invertebrate animals flourished before 



the vertebrata, and that in the latter class fish, reptiles, birds, 



and mammalia made their appearance in a chronological 



order analogous to that in which they would be arranged 



zoologically according to an advancing scale of perfection in 



their organisation. In regard to the mammalia themselves, 



they have been divided by Professor Owen into four sub-classes 



modifications 



In the two low- 



est, called Lyencephala and Lissencephala, are included the 

 marsupials and insectivora, 



met 



Next 



fossil in the secondary rocks, 

 the Gyrencephala, in which Cetaceans, Proboscidians, Rumi- 

 nants, Carnivora, and Quadrun 

 found fossil in tertiary strata. 



Quadrumana 



nior 



lead in organisation and instinct among the Quadrumana, 

 coming also last in the order of time. To crown the whole, 

 the series ends with the fourth great sub-class, the Archen- 





man 



