RELATIONSHIP OF AUSTRALIAN TERRESTRIAL FORMATIONS. 305 



difficulties of the matter would have at once become apparent to 

 them, as it now appears to Australian geologists, in attempting to 

 correlate their rocks with European equivalents. 



In further opposition to some of the statements objected to, 

 we have to look at the following facts : — 



(1) Among the prevailing genera of plants in the Carboniferous 

 beds of Europe, are Alethopteris, A^europteris, Odontopteris, 

 Pecopteris, ISpltenopteris, T(nniopteris, Danfea, Ulodendron, Poa- 

 cordaites. Eight out of the nine genera also prevail in the 

 Mesozoic rocks of Tasmania, while not one of them is present 

 among the coal plants of the Carboniferous rocks of the same 

 region ! 



(2) The most abundant and typical genus of plants in the 

 Carboniferous rocks of Tasmania and Australia, is a Glossopteris 

 (several species). The genus is not represented in the rocks of 

 the same age in Eui'ope, but a representation spai-ingly occurs in 

 the Upper Mesozoic beds of that region. 



(3) The genera FliyUotheca, Podozamites, Pterophylluin, Scdis- 

 biiria, GinkgophyUnm, Baiera, Zeugophyllites, Sagenopteris, 

 Thinnfeldia, Kliacophyllum, are very characteristic in what is 

 deemed, on the evidence of local stratigraphic succession, to be the 

 lowest division of the Mesozoic rocks of Tasmania. Seven of 

 these are equally chai-acteristic of the middle or upper division 

 of the Mesozoic x'ocks of Europe. 



(4) The fauna and flora of the Tertiary period in Europe, are 

 in many important respects more akin to the existing floras and 

 faunas of Australia and Tasmania than are the existing floras and 

 faunas of both regions ; and conversely : — 



(5) The flora of the Tertiary period in Australia and Tasmania 

 is in many important respects more akin to the existing flora of 

 Europe than are the existing floi'as of these distant regions. 



Many otlier striking examples, unmistakeable in their character 

 and in the order of their appearance, might be cited to prove : — 



That the order of the appearance of genera or other afl[inities 

 in plants in the strata of any one region, atibrds no reliable clue 

 to the order in which plants of similar genera or other affinity 

 make their appearance in the strata of far distant regions ; and 

 that the known history of the order of appearance of chai'acter- 

 istic genera of plants in Australasia and Europe, leads us to 

 expect that inversion of the order after an epoch of interval is 

 more likely to occur, than homotaxial, harmonious, and progressive 

 parallelism. 



If these considerations are admitted, and I do not see how they 



can be disputed from facts, it follows that theories of the succession 



of rocks in Australia and of their relationship with the known 



subdivisions of far distant regions, based upon the study of the 



u 



