INTRODUCTION. xli 



and New South Wales, and possibly also in South Africa. "\Ve 

 are able therefore to trace to some extent the fate of the various 

 elements of the Palaeozoic flora as recorded in rocks of Triasso- 

 Ehaetic age. We find that by this time some members of the flora 

 had become extinct, though representatives of perhaps the majority 

 of the more important genera still survived. These, in some cases, 

 inhabited regions more or less conterminous with the pre-existing 

 Palaeozoic continent, but the more marked characteristic of this 

 period is the evidence of a widespread migration i of many of the 

 Palaeozoic genera far beyond the boundaries of Gondwanaland. 



This conclusion is not based on the distribution of such 

 elements of a Mesozoic facies as are present in the Glossopteris 

 flora, as well as in the northern type of Palaeozoic vegetation. 

 We recognise such elements in the genus Teemopteris among Fern- 

 like plants, the Cycadophyta, the Ginkgoales, and the Coniferae, 

 such as Voltzia, associated in India and elsewhere with Glossojrteris 

 and its allies. The presence of these types, in common with the 

 marked migration in early Mesozoic times of certain genera 

 essentially of a Palaeozoic facies, serves but to confirm the con- 

 clusion that the change in the vegetation from a Palaeozoic to 

 a Mesozoic facies was of an extremely gradual nature. In the 

 Triassic rocks (excluding the Khaetic) we have a flora which is 

 essentially a Transition flora, in which the older Palaeozoic types 

 one by one die out, and gradually give place to newer types of 

 a Mesozoic facies, whose first incomings, as in the case of the above- 

 mentioned families, we can trace back as far as the Carboniferous 

 rocks. 



Put when we turn to the truly Palaeozoic genera, such as 

 Sehizoneura, Phyttotheca, and NeuroptericUum, we find in several 

 cases that they have spread as far as Western Europe in Triassic 

 times. It is a moot point at present how far the presence of such 

 survivals of the Glossopteris flora may be regarded as dominant 

 members of the flora of the Triassic (excluding the Phaetic) period. 

 The difficulty arises from the fact that the vegetation of the Triassic 

 rocks of Europe is still very imperfectly known. Put whether we 

 regard such survivals as characteristic and dominant elements in 

 the flora of that Transition period or not, there can be no doubt 



Seward (03-), p. 835. 



