NEGATIVE EVIDENCE. 



445 



have proved to belong to the low organized Marsupialia. The 

 doubt, when it has existed, lies between this and the Insecti- 

 vorous order, also low in the class according to cerebral 









Table of 



Geologic 



al Distribution 



of Mammals. 











J/Evrsw-'\Rcder\t- 

 -pislia,.|-wi.. 



Xnsecft- 

 -vora. 



-%ra°^iB^a. 



Cetacea 



Sirenia. 



Toxo Lor 



-tut. 



Fro los- 

 -adea. 



.Per is s- 



-dcctyLa. 



Arti'j- 

 -dacLyla) 



Carnu 

 •vara ■ 



puo.dru.- 

 -mana.. 



Bimana 





Modern 



m 1 bi 



^ 





1 



m 



1 





4 



A 



WM 



m 



■ 



V 



Jftienv 



Pliocene 



T 



■ 



f 



1 



I 



1 



t 



1 



1 



■ 



f 



■ 





PZiocene 



Miocein, 



f 



1 



I 



1 



1 



■ 



1 





f 



■ 



V 



■ 



r 





■Zkfwcene 



.Eocene 



1 



f 



1 



1 





1 









f 



f 



! 



f 





Eocene 



f 













f 





Creta.- 



.cious 































Creia,- 

 .ceoas 



■WeaUcn 































VSalicTi 



Purlccls. 



• 





1 

























B»i«l 



Oolvfe 



i 



*re 



? 







? 









? 











Oolite 



-Lias 































Zt«a 



IVi'as 



Mtralesfa 



























2nss 



Ferm.Ca.rv 



























l 



.Brmicnv 



Fig. 174. 



characters.* One example only, from Stonesfield oolite, the 

 Stereognathus, may prove to be a minute Ungulate, as is indi- 

 cated by the note of interrogation under Perissoclactyla. The 

 similar mark, under Cetacea, refers to the fossil, probably 

 washed out of an Upper Oolitic bed, mentioned at p. 355. The 

 Marsupialia recur, under distinct generic forms, in the eocene 

 strata, and, according to actual knowledge, presented their 

 fullest development in post-pliocene times, more especially in 

 Australia. The orders Bruta, Perissoclactyla, and Cccrnitora, 

 have become reduced in numbers ; the Proboscidia still more 

 so; the representatives of the singular group Toxoclontia have 

 wholly disappeared. 



The sum of the evidence which has been obtained seems 

 to prove that the successive extinction of Microlcstes, Amphi- 

 th&ria, Spalacotheria, Triconodons, and other mesozoic forms 

 of mammals, has been followed by the introduction of much 

 more numerous, varied, and higher-organized forms of the 

 class, during the tertiary periods. 



* Owen, "On the Classification and Geographical Distribution of the Mam- 

 malia," 8vo, 1859. 



