58 Proceedings of the Royal Society of Victoria. 



evidence, in the shape of similar material t'n situ, be obtained the 

 question as to the age of this tooth must remain unsettled, the 

 balance of evidence being in favour of Miocene. The earliest 

 fossil mammal known in Australia was found many years ago in 

 the Eocene Turritella beds of Table Cape, Tasmania. This was 

 referred to by Mr. S. H. Wintle as a " fossil wallaby" (2). Mr. 

 R. M. Johnston has since then spoken of the specimen as 

 Halmaturus (3). 



Whatever the exact nature of the Tasmanian fossil may be, it 

 is undoubtedly a terrestrial mammal, and as its being in situ 

 in the Eocene Ijeds appears certain (4), there is no a priori 

 argument against the tooth we are dealing with being as old 

 as Miocene. 



As regards the zoological position of the specimen we cannot 

 do better than quote Mr. De Vis' letter. 



"The tooth which you are good enough to send me is unques- 

 tionably one of the upper premolars of a large diprotodont 

 mai^supial. Had it occurred in an ordinary turbary or lacrustine 

 deposit I should have had little hesitation in saying that it was 

 the right permanent upper premolar of the gig;intic Kangaroid, 

 Patorchestes nzae/, Ow., the largest of the transition forms 

 between the true kangaroos and the Nototheriidtv. But if it were 

 really derived from a deposit of Meiocene age it would be well 

 nigh impossible for it to belong to P. azaei, an associate of 

 living mollusks, and it must therefore be provisionally referred 

 to an earlier species of the genus. In either case the tooth is 

 of much interest, whether it leads us eventually to attach to 

 the Nototherian fauna a much higher antiquity than we have 

 hitherto imagined, or whether it merely exemplifies the premolar 

 of P. azael in a much younger and more perfect state than the 

 only other tooth hitherto known, which is greatly degraded by 

 wear. 



I hope you will be able to fix the real age of the tooth by 

 finding bones of the like origin /;/ siiur 



Our object in writing this note is to bring before any geologists 

 working in the neighbouriiood the desirability of keeping a look 

 out for similar specimens in the Miocene beds, though the marine 

 conditions then prevailing, coupled with the fact that the band 

 yielding the shark's teeth is only reached by digging below high 

 water level, render the chances of finding them somewhat remote. 



