87 



forms as our knowledge increases is most significant. 

 According to tlie principle which has been adopted bj Mr. 

 Lyell, and, through him, by nearly all the English geologists, 

 this low percentage of living representatives indicate rather 

 more an eocene than a miocene age for our marine teds of 

 Table Cape. This, too, is in accord with views recently 

 expressed by Mr. Woods. 



There is no reason why the same principle, that of per- 

 centage of extinct to living species, should not apply to 

 Australia as well as to Europe. The only objection which I 

 have raised against tracing relations with European beds 

 referred more to identification with particular deposits than 

 to periods based upon the degrees of difference between the 

 life of the past and present. The objection to applying the 

 percentage princij)les in the latter respect is insufficiency of 

 material for purposes of comparison, but I think the force 

 of this objection, in the light of our present knowledge, is 

 not of great weight. 



To Baron von Miieller, more than to any other, we owe 

 the knowledge we have of our relations between the present 

 and past of our Australasian Botany. There are now nearly 

 100 fossil plant remains of the tertiary drifts figured and 

 described, the greater part of which has been carefully 

 determined by the learned Baron from fruits ; and, though, 

 for the most part, conclusions based upon plant remains are, 

 as compared with testaceous remains, less satisfactory, 

 yet the acknowledged skill and scrupulous care of our 

 leading phytologist are sufficient warrant for taking the 

 evidence from plant remains as of equal value with the 

 evidence from testaceous remains. With the doubtful 

 exception of remains of two ferns, Lomaria and Tricho- 

 manes, found by me near Launceston, all the plant remains 

 figured or described are of extinct species. This fact, more 

 than any other, speaks of the great antiquity of the formations 

 in which they occur. Although the orders are principally of 

 the same character as the existing ones, yet both the genera 

 and species are for the most part distinct from existing 

 genera and species. 



I belieye there is yet much undescribed material in local 

 museums and in collectors* hands, but I do not expect that 

 it will, when described and published, do more than confirm 

 conclusions already inferred from existing data. Much may 

 yet be done towards increasing our knowledge of our land 

 and freshwater fauna of tertiary age. Such evidence will be 

 of considerable importance in determining the relations of 

 isolated leaf beds. 



In this respect the fossil shells of the Geilston Bay yellow 

 limestone are of great value. Hitherto only two of them 



