BOTANICAL AND CHEMICAL CHARACTERS OF EUCALYPTS. 115 



In the sixth place, it appears that tlie geogi'apliy of Australia has 

 changed considerably since the Cretaceous period. At that time 

 Australia appears to have been occupied in part by a great central 

 sea, surrounded by wide expanses of low-lying plains, mainly sandy 

 in nature, the climate of the continent being mild and moist. That 

 condition has now passed, the central sea has been drained, the old 

 eastern plain has been uplifted to form high plateaus ; these plateaus 

 in turn have been covered in places with dense lava floods ; the plateaus 

 themselves have been worn away, in part, by streams and the material 

 so worn has been distributed by the inland-flowing streams to form 

 great alluvial plains, whilst the old moist and genial climate has been 

 highly differentiat-ed coincidently with these changes of topography. 

 This suggests that the vegetation of Australia has been called upon 

 to adapt itself to harsher conditions since the isolation of Australia. 

 On the other hand, the great similarity to each other of the tropical 

 Myrtffi suggests that Eugenia, Myrtus, and Myrcia developed under 

 uniform and mild climatic conditions. 



A consideration of these principles suggests that Eucalyptus was 

 developed from the fleshy-fruited Myrtace^ after the sepai'ation of the 

 great tropical lands ; that it was developed in warmer Australia, pos- 

 sibly the Northern or the more North-Eastem portion ; that it was 

 an adaptation in the first instance to the warmer sandstone areas and 

 later either to drier climate or to heavier soils or to the colder localities. 



BlBLIOGEAPHY. 



(1) R. H. Cambage, Presidential Address, Roy. Soc. New South Wales. 1913. 



(2) F. v. MuELLEB, ' Eucalyptographia.' Art. E. amygdalina. 



(3) H. G. Smith, Presidential Address, Roy. Soc., New South Wales. 1914. 



(4) H. G. Smith, ' On the Occurrence of Calcium Oxalate in the Barks of the Eucalypts. * 



Proc. Roy. Soc, N.S.W., 1905. 



(5) R. T. Baker and H. G. Smith, ' Research on the Eucalypts,' Sydney. 1902. 



(6) R. T. Baker and H. G. Smith, ' On the Relation of Leaf- Venation and the presence 



of certain chemical constituents in the Oils of the Eucalypts,' Proc. Roy Soc, 

 N.S.W., 1901. 



(7) R. T. Baker and H. G. Smith, ' Research on the Eucalypts of Tasmania,' Proc. 



Roy. Soc, Tasmania, 1912. 



(8) Cuthbert Hall, ' On Eucalyptus Oils, especially in relation to their Bactericidal 



Power,' M.D. Thesis, published privately. 



(9) White's ' Voyages to New South Wales,' 1790. 



(10) R. Robinson and H. G. Smith, 'A Note on the Phenols occurring in some 



Eucalyptus Oils.' Proc. Roy. Soc, N.S.W., 1914. 



(11) H. G. Smith, ' On the Butyl Ester of Butyric Acid occurring in some Eucalyptus 



Oils." Proc. Roy. Soc, N.S.W., 1914. 



(12) H. G. Smith, ' On a Eucalyptus Oil containing 60 per cent. Geranyl-acetatc' 



Proc. Roy. Soc, N.S.W., 1900. 



(13) H. G. Smith, ' On the Essential Oils of the Angophoras,' Proc. Roy. Soc, N.S.W., 



1913. 



(14) H. G. Smith, 'On the Kinos or Astringent Exudations of 100 species of 



Eucalyptus.' Aust. Ass. Adv. Sc, Melbourne, 1913. 



(15) R. Robinson and H. G. Smith, ' Eudesmin and its Derivatives,' Part I. Proc. 



Roy. Soc, N.S.W., 1914. 



(16) H. G. Smith, ' On Eucalyptus Kinos, their value for Tinctures and the non- 



gelatinisation of the products of certain species.' Proc Roy. Soc.,N.S.W., 1904. 



(17) H. G. Smith, ' On the absence of Gum, and the presence of a new diglucoside in 



the kinos of the Eucalypts.' Proc Roy. Soc, N.S.W., 1904. 



(18) H. G. Smith, ' On Myrticolorin.' Trans. Chem. Soc, London, 1898. 



I 2 



