INTRODUCTION. 



1. BOTANICAL AFFINITIES OF THE GLOSSOPTERIS 



FLORA. 



In order to understand the botanical affinities of the Glossopteris 

 flora it will be necessary to compare it somewhat closely with 

 the Northern type of Pernio - Carboniferous vegetation, and also 

 with its immediate predecessor in geological time, the flora of 

 the Upper Devonian and Lower Carboniferous rocks, which, as 

 we have pointed out, was characterised by worldwide uniformity 

 of distribution. 



The plant-remains of the Upper Devonian period are un- 

 fortunately scanty, but within recent years our knowledge of 

 these ancient types of vegetation has been considerably increased. 

 It is interesting to note that beds of this age within the Arctic 

 regions have been found to furnish more valuable material in 

 this respect than those developed elsewhere. The Devonian floras 

 of several Arctic lands are now known, thanks especially to the 

 researches of Nathorst. 1 Among the other sediments of this age 

 which have yielded plant-remains, the more important are those of 

 Southern Ireland, 2 Belgium, 3 Austria, 4 Russia, 3 and Canada. 6 



In the Lower Carboniferous deposits of Europe and North America, 

 plant-remains are more numerous and less fragmentary, and con- 

 sequently the flora of this period is better known. It appears, 

 however, to be essentially similar in type to that of the Upper 

 Devonian rocks, and in all probability we may regard the Upper 

 Devonian and Lower Carboniferous floras as constituting one great 

 botanical epoch. Plant-remains belonging to the latter period 



1 Nathorst (94), (00), (02 1 ), (04). 



2 See Kidston (86), pp. 228-236. 



3 Crepin (74), (75). 



4 Stur (81) ; Potonie & Bernard (04). 



5 Schmalhausen (94). 



6 Dawson (59), (71). (81). 



