LIFE ON THE EARTH. 119 



come the Insectivora of Stonesfield, which in part 

 belong to the Marsupialia 1 , and one, the latest of 

 the discoveries there, the Stereognathus Ooliticus, 

 which belongs to an artiodactylous order 2 . Next 

 come the Insectivora and Rodentia of Purbeck 3 , also 

 in part Marsupial. Then as far as yet discovered 

 a blank follows; there is no Mammal known of the 

 Cretaceous period, but the Tertiary Strata reveal 

 several successive groups. The whole series stands 

 thus, if we include more than the British Fauna: 



Pleistocene and Pleiocene. Full series of orders of mammalia. 

 Meiocene...Pachydermata and other families. 



Eocene Pachydermatous prevail. 



Purbeck ...Marsupial Insectivora, Rodentia. 

 Stonesfield. .Marsupial Insectivora, Artiodactylous genus. 

 Trias Marsupial Insectivora. 



ANTIQUITY OF THE EARTH. 



Geologists have been much censured for vainly 

 endeavouring to assign measures of time to the 

 seemingly vague and shadowy ages of the Trilobites 

 and Belemnites; nor have they escaped censure for 



1 Buckland, Bridgewater Treatise and Owen, Brit. Foss. Mam- 

 malia. 



2 See for the latest Classification of Mammalia the Rede Lec- 

 ture by Prof. Owen, 1859. 



3 The capital discovery of Mr Beckles. 



