144 TERTIARY ROCKS OF AUSTRALASIA, 



ing the classification which, on doubtful data, groups many 

 of them as Miocene. 



In commenting upon the development of Dicotyledons, 

 Mr, Gardiner states : " Floras from Spitzbergen in the 

 north to Australia in the south have been classed as 

 Miocene from a very slender fancied resemblance to those 

 of Switzerland, and a great series of strata have been 

 assigned without sufficient reason to that age, not only in 

 Central Europe, but in such distant lands as Greece, 

 Madeira, Borneo and Sumatra, Sachalin and Alaska, and, 

 in fact, wherever other evidence of age was absent." He 

 also clearly enforces views, already advanced in this work, 

 that, in utilising the floras of different countries " for com- 

 parison, the differences of latitude and longitude must be 

 taken into account. Nor have we a right to suppose that 

 all the plants preserved from an immense number of 

 localities grew at the same elevation above the sea, while 

 they may also have lived on very different stations and 

 under relatively dry or moist climates." The danger of 

 determining the ages of fossil floras in remote parts of the 

 world by comparing and estimating the percentages com- 

 mon to those of Europe is also very great ; for, as Mr. 

 Gardiner remarks : " Not only have we to keep in mind 

 the similarity that dicotyledonous leaves belonging to 

 different genera bear to each other, a likeness increased by 

 the process of fossilization where the matrices are similar, 

 but the fragmentary condition of the specimens usually 

 brought from distant countries . , , " And additional 

 caution is urged by this careful observer by citing the 

 following illustration : — " Were we to take an armful of 

 fallen leaves at random from each country, such as Siberia, 

 Japan, Sumatra, Australia, New Zealand, Madeira, Scot- 

 land, France, Greece, and the United States, and compare 

 them together after the manner of palaeontologists, is it 

 likely that we should find grounds for supposing that they 

 all belonged to floras growing synchronously?" Such 

 reasoning is most wholesome at the present time, and 

 amply justifies the course adopted by the author in respect 

 of the broader subdivision suggested for Tasmania. Mr. 

 Gardiner, however, states tkat his remarks are not intended 

 to discredit those who have laboriously worked at the task 

 of deciphering fossil floras, but " simply meant to warn 

 bose who have to make use of the facts arrived at, that 



