THE CARBONIFEROUS FLORA. 



147 



be inferred from the vegetation, this in the northern 

 hemisphere presented a greater expanse of swampy flats 

 little elevated above the sea than we find in any other pe- 

 riod. As to the southern hemisphere, less is known, but 

 the conditions of vegetation would seem to have been es- 

 sentially the same. 



Taking the southern hemisphere as a whole, I have 

 not seen any evidence of a Lower Devonian or Upper Si- 

 lurian flora ; but in South Africa and Australia there are 

 remains of Upper Devonian or Lower Carboniferous 

 plants. These were succeeded by a remarkable Upper 

 Carboniferous or Permian group, which spread itself all 

 over India, Australia, and South Africa,* and contains 

 some forms ( Vertebraria, Phyllotlieca, Glossopteris, &c. ) 

 not found in rocks of similar age in the northern hemi- 

 sphere, so that, if the age of these beds has been correctly 

 determined, the southern hemisphere was in advance in 

 relation to some genera of plants. This, however, is to 

 be expected when we consider that the Triassic and Ju- 

 rassic flora of the north contains or consists of intruders 

 from more southern sites. These beds are succeeded in 

 India by others holding cycads, &c, of Upper Jurassic 

 or Lower Cretaceous types (Eajmahal and Jabalpur 

 groups). 



Blanford has shown that there is a very great similar- 

 ity in this series all over the Australian and Indian re- 

 gion, f Hartt and Darby have in like manner distin- 

 guished Devonian and Carboniferous forms in Brazil akin 

 to those of the northern hemisphere. Thus the southern 

 hemisphere would seem to have kept pace with the north- 

 ern, and according to Blanford there is evidence there of 

 cold conditions in the Permian, separating the Palaeozoic 



* Wyley, "Journal Geol. Society," vol. xxiii., p. 172 ; Daintree, ibid., 

 vol. xxviii. ; also Clarke and McCoy. 



f " Journal Geol. Society," vol. xxxi. 



