1 54 TERTIARY ROCKS OF AUSTRALASIA, 



Woods, who was the first person who made a thorough 

 investigation of our Tertiary marine beds, has come to 

 regard the evidences of the fauna in a different light. He 

 infers that " our Lower Tertiary fauna is not a tropical, 

 or even a sub-tropical one." " All that we can say," he 

 continues, " is that certain species which are found still 

 living now inhabit the tropics, while others remain where 

 they are, and generally very many of the genera are now 

 to be found in a warmer climate. It is very remarkable 

 to find specimens of reef-building corals, but we can hardly 

 assert under what conditions they lived, since they are so 

 very different from the reef-builders of the present day. 

 I suppose it is hardly attempted to account for the reef- 

 building corals which we find in the British coral rag 

 (oolitic), for instance, by climatal conditions alone. He 

 further adds : " It seems to me that we are too imperfectly 

 acquainted with the circumstances which govern the 

 migration of species at present to be able to apply even 

 generally any reasoning to such facts as those before us. 

 Climate alone will not account for them." The difficulty 

 of arriving at correct conclusions is not lessened by confining 

 attention to the flora ; for the general prevalence of the 

 oak, birch, elm, alder, and beech in the Tertiary lacustrine 

 deposits, and their almost total disappearance in Australia 

 at the close of the Palseogene period, are matters not 

 easily disposed of by references to any one single cause. 

 From the knowledge of the distribution of such types at 

 the present day, we would be justified in inferring a very 

 temperate clime, in Tasmania at least, during the earlier 

 or middle part of the Tertiary period. And this inference 

 is borne out to some extent by the fact that one of the 

 survivals — the genus Fagus — is now only to be found in 

 moist situations in alpine and sub-alpine heights in Tas- 

 mania, whilst the genus Eucalyptus, found rarely in the 

 Tertiary deposits of Tasmania, now generally predomi- 

 nates over all other trees in the drier and warmer parts 

 from the sea level to sub-alpine heights. Whatever 

 influences were at work, therefore, towards the close of the 

 Middle Tertiary period, it is evident in Australia that 

 they operated in favour of the spread of the Proteacece 

 and MyrtacecB, and against the deciduous types of trees 

 such as the oaks, elms, beeches, and alders formerly pre- 

 vailing ; and it is equally true that effects the reverse of 



