HORN EXPKniTION SUMMARY. 17.1 



Tasmania, Victoria and soutliorn New .South Wales tlie name Euronotiaii slumld 

 be i-etainc(l, wliilst for tlie second, including Queensland and nortlicrn New .South 

 Wales, he suggested the name Papuan. 



There is no doul^t but that Mr. Hedley's division of tlie Euronotiaii into 

 tliese two parts is essential so far as zoology is concerned, in fact such a. division 

 w;i,s already liinted at l)y Professor Tate in respect of botanical fcatuies in the 

 remark tliat tlie Euronotiaii type was dominant in tlie south and east part of tlie 

 wider I'egion to which he ajiplied tlie term. 



In dealing with the (piestion of the relations of the tloia and fauna of the 

 various parts of Australia as we find them cxi.sting at the present time, peiliaps 

 the point of most importance is the demonstration of the fact th.af- for a, long 

 period of time the east and west paits of the continent were separated from one 

 another liy an impenetrable barrier of some description. I\lr. Iledley says :* 

 " Owing to fundamental errors of his interpretation of Australian geology, 

 Wallace's treatment of the subject in ' Island Life' is of but slight va,lue." It is 

 f[iiite true that, owing to the imperfection of our geological knowledge when Mr. 

 Wallace wrote, he was mistaken in suggesting that a great inland Tertiary sea 

 acted as a barrier, Init whilst this is so, tiie main facts of central importance were 

 most clearly enunciated by Wallace who, arguing from a knowledge of .Sir Joseph 

 Hooker's work, wrote :t "The.se facts again clearly point to tiic conclusion that 

 soutli-western Australia is the remnant of the inoie extensive and more isolated 

 portion of the continent in which the peculiar flora was principally developed. 

 But whilst this rich and )>eculiar Hora was in process of formation, the 

 eastern portion of the continent must either have been widely separated from the 



western or had perhaps not yet risen from tlie ocean During some 



portion of the Secondary period therefore this (/.c, the east) side of Australia 

 must have lieen almost wholly submerged beneath the ocean ; and if we suppose 

 that during tliis time the western part of the continent was at nearly its ma.ximuin 

 extent and elevation, wc shall have a suthcient explanation of the great ditlerence 

 between the Hora of Western and Eastern Australia, since the latter would only 

 have been able to receive immigrants from the former, at a later period, and in a. 

 more or less fragmentary manner." 



Whilst the more exact nature of the Viarrier and of the successive geological 

 changes occurring in the c(MitraI area of the continent since Creta,ceous times have 

 lieen demonstrated by other workers, notably by Messrs. Etheridge and Jack-, 



>■ LiK\ iit.,]>. iA4. t " Island Life, 1st edit., 1880, p. 4fi4. 



