302 PROCEEDINGS OF SECTION C. 



6._H0W FAR CAN AUSTRALIAN GEOLOGISTS 

 SAFELY RELY UPON THE ORDER OF SUCCESSION 

 OF THE CHARACTERISTIC GENERA OF FOSSIL 

 PLANTS OF A FAR DISTANT REGION, IN THE DE- 

 TERMINATION OF THE ORDER AND RELATIONSHIP 

 OF AUSTRALIAN TERRESTRIAL FORMATIONS? 



By R. M. Johnston, F.L.S., Government Statician, Tasmania. 



To Australian geologists, the question proposed at the head of this 

 paper is of the very deepest importance. Hitherto, questions 

 relating to the order and relationship of Australian rocks have 

 been, in a very large measure, influenced by the opinions of eminent 

 Palaeontologists, formed mainly upon deductions made with respect 

 to the order of the appearance of certain genera in Europe, or in 

 far distant regions. 



I wish it to be taken for granted in criticising some of their 

 conclusions, that I yield to no one in esteem for their valuable 

 labours. Happily for me, the question upon which I may have to 

 express any widely dift'erent opinion is not one affecting the exact 

 determination or classification of the organisms themselves. The 

 question which I propose to confine attention to does not raise 

 doubt as regards the determination, or affinities of the plants 

 characterisf ic of particular rocks, Although, even in such matters, 

 there are many obscure points from which difficulties may arise. 



The question here discussed is of quite a different nature, and 

 may be expressed as follows : — How far does the assemblage of 

 the characteristic genera of a particular formation in a distant 

 region (say Europe) afford a clue to tlie proper determination of 

 the stratigraphical position and relationsliip of Australian rocks ? 

 The belief that the community or resemblance of organic remains 

 in rocks of different regions indicates strict contemporaneity — 

 once so prevalent amongst Palteontologists — is not yet dead, 

 although the recent utterances of a few leading authorities show 

 that such a belief is no longer tenable. 



Geikie for example, states in his last work* that " similarity or 

 identity of fossils among formations geographically far apart, 

 instead of proving contemporaneity may be compatible with great 

 discrepancies in the relative epochs of deposition." 



* Text Book of Geology, p. 619. 



