INTEODDCTION. XY 



Some difficulty has occasionally been experienced in assigning 

 species to their correct geological position in the Tertiary. In. 

 regard to the Australian "Eocene" and Miocene I have, where 

 possible, followed the classification of Professor Tate in his various 

 works quoted, although, as will already have been noticed, 

 I have considerable doubt whether the "Eocene" of that continent 

 is really homotaxial with that of North-Western Europe. Again, 

 in certain localities where two formations occur, as at Muddy Creek, 

 Trclissick, etc., it has sometimes been doubtful from which horizon 

 the particular specimens being catalogued came. In such cases 

 I have been much assisted by the useful list of Muddy Creek fossils 

 drawn up in Mr. John Dennant's memoir^ on the beds in that 

 locality, which has been quoted from time to time. Again, Sir 

 James Hector's list^ of New Zealand localities with their geological 

 horizons have proved valuable in the same connection ; whilst 

 Professor Button's Catalogue ' has of necessity been i-eferred to on 

 many occasions. Nevertheless, there are a few specimens from that 

 colony, the exact provenance of which I have not been able to fix, 

 as will be observed ; such specimens have, for the most part, been 

 in the Museum for many years, and the name of the locality, 

 which they bear, may possibly represent a place where a camp was 

 temporarily made. The collection from Parimoa appears to come 

 from two horizons, the Miocene and Pliocene, and in the case of a 

 new record for that locality it has been found impossible to give the 

 geological age with certainty. At Wanganui, again, both Pliocene 

 and Post-Pliocene beds are found ; in general it has not beea 

 difficult to assign a particular species from this locality to its correct 

 horizon, but there are exceptions. These, and similar points, I 

 must leave to Colonial geologists, who alone, by study on the spot, 

 can satisfactorily clear them up. The locality of Limestone 

 Creek, Glenelg river, Victoria, is here called Post-Pliocene, instead 

 of Newer Pliocene ; I believe it will ultimately be found to be 

 younger than the true Pliocene. 



It should be explained that by " Australasia " throughout this 

 work is meant, the Australian continent, Tasmania, New Zealand, 

 and the Chatham Islands. 



1 Trans. Roy. Soc. South Aust. Tol. xi. 1889, p. 30. 



- Kep. Geol. Exp. 1890-91, p. 121 (and other Reports in the same Series). 



» Catalogue Tert. Moll, and Echin. X.Z. 1873. 



