FOSSIL PLANTS AS RECORDS 175 



being submerged and appearing again as debris drifted 

 and collected over them. Such a land area must have 

 differed greatly from the Europe now existing, in all its 

 features. But the whole continent did not consist of 

 these flats; there were hills and higher ground, largely 

 to the north-east, on which a dry land flora grew, a 

 flora where several of the Pteridosperms and Cordaites 

 with its allies were the principal plants. These plants 

 have leaves so organized as to suggest that they grew 

 in a region where the climate was bright and dry. 



A fossil flora which has aroused much interest, 

 particularly among geologists, is that known as the 

 Glossopteris flora. This Palaeozoic flora has in general 

 characters similar to those of the European Permo- 

 Carboniferous, but it has special features of its own, in 

 particular the genus Glossopteris and also the genera 

 Phyllotheca and Schizoneura, 



These genera, \vith a few others, are characteristic 

 of the Permo-Carboniferous period in the regions in the 

 Southern Hemisphere now known by the names of Aus- 

 tralasia, South Africa, and South America, and in India. 

 These regions, at that date, formed what is called 

 by geologists " Gondwanaland ". In the rocks below 

 those containing the plants there is evidence of glacial 

 conditions, and it is not impossible that this great 

 difference in climate accounts for the differences which 

 exist between the flora of the Gondwanaland region and 

 the Northern Hemisphere. Unfortunately we have: not 

 microscopically preserved specimens of the Glossopteris 

 flora, which could be compared with those of our own 

 Palaeozoic.^ 



To describe in detail the series of changes through 

 which the seas and continents have passed belongs to 

 the realm of pure geology. Here it is only necessary to 

 point out how the evidence from the fossil plants may 

 afford much information concerning these continents, 



1 The student interested in this special flora should refer to Arber's British 

 Museum Catalogue of the Fossil Plants of the Glossopteris Flora. 



