BY R. M. JOHNSTON, F.L.S. 143 



the associated species having hving representatives. The 

 manifest objection to the use of such terms for the classifi- 

 cation of subdivisions of the Tertiary period throughout 

 the world is, that it fixes the number of subdivisions ; and 

 as it is very improbable that characteristic groups in 

 different countries, especially in opposite hemispheres, will 

 be found on stratigraphic and organic grounds to maintain 

 anything approaching a natural division into three, or 

 even four or more groups, the terms are often a hindrance. 



For example, in Australia and Tasmania the marine 

 deposits, though very extensive, do not reappear again 

 and again throughout the epoch, and there are no means, 

 therefore, of determining with satisfaction the exact posi- 

 tion of the extensive leaf-bed and lignite formations* such 

 as might be obtained if the latter were intercalated with 

 successive marine deposits showing marked differences of 

 percentage of species having living representatives, as in 

 Europe. In this region, the adoption of the European 

 classification would be most unsuitable and very deceptive. 

 It is apparent, therefore, that for Australasia a broader 

 distinction between the older and younger Tertiary deposits 

 is absolutely necessary ; and as the terms Palceogene and 

 Neogene have already been recognised as indicating the 

 older and younger Tertiaries respectively, they have been 

 adopted by the author as most suitable for the classifica- 

 tion of these rocks in Australia and Tasmania. 



This arrangement is all the more necessary when we 

 come to consider that the introduction of the fourth group, 

 " Oligocene," between the Eocene and Miocene, is by 

 many geologists deemed to be doubtful and arbitrary even 

 as apphed to Enghsh rocks, although fairly justifiable for 

 some of the formations in France, Germany, and in other 

 European countries. It is also advisable to make the 

 broader classification for other reasons, for there is still 

 much that is uncertain in the groupings of English and 

 other European countries. 



Mr. Starkie Gardiner has repeatedly drawn attention 

 to the unsatisfactory classification of the vegetable deposits 

 of Europe, and has given many weighty reasons for revis- 



» The attempt to determine the exact age of these deposits by the aid of 

 successive flows or sheets of eruptive basalt, as in Victoria, is far from 

 satisfactory, and affords no reliable guidance to the relationship of various 

 beds in independent basins. 



