THE CARBONIFEROUS FLORA. 



147 



m 



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 (Vertcbraria, Phyllotheca, Glossoplcris, &c.) 

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

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

 determined, the southern hemis})liere 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 (Rajmahal and Jabalpur 

 groups). 



Blanford has shown that there is a very great similar- 

 ity in this series all over the Australian and I'ldian re- 

 gion, f Ilartt 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 Palceozoic 



i."- 



* Wyley, "Journal Geol. Society," vol. xxiii., p. 1'72; Daintree, ibid., 

 vol. xxviii. ; also Clarke and McCoy. 



f " Journal Geol. Society," vol. xxxL 



