3IO PATAGONIAN EXPEDITIONS: PAL/EONTOLOGY. 



species have been collected here ; the one is Ostrea ingens in a form which 

 approaches distinctly the Cape Fairweather type of this species, the other 

 is a Pecten, apparently P. gcminatiis, but it is to be remarked that only 

 casts have been found which render the identification doubtful : we may 

 have to deal with P. actinodes. 



While thus the correlation of the Cape Fairweather beds with other 

 deposits still remains somewhat doubtful, we may safely say that they 

 themselves are of Pliocene age. Further investigations of corresponding 

 beds of other localities, especially of the marine "Tehuelc.he" formation 

 of Ameghino are very desirable, and will probably throw much light upon 

 the Cape Fairweather beds. 1 



ORIGIN AND DEVELOPMENT OF THE PATAGONIAN MARINE 



FAUNAS. 



i. THEORY OF "ANTARCTICA." 



We may take the marine fauna of the Miocene Patagonian beds as the 

 standard for all fossil Patagonian faunas, since it is the only fauna that 

 we may call "well-known." Of the Magellanian fauna only a small part 

 is known, and the Cape Fairweather beds also contain only a compara- 

 tively small number of species. 



One of the most striking characters of the Patagonian fauna is, as we have 

 seen above (pp. 299302), the presence of a number of species which show 

 distinct affinities with New Zealandian and Australian fossils. This rela- 

 tion of Patagonia to New Zealand and Australia is no new feature : it has 

 been observed before in land and fresh-water animals, and also in marine 

 animals and in plants 2 by numerous authors, and we possess various 

 theories for the explanation of this remarkable zoogeographical fact. 



A very good although not quite complete review of the theories 

 connected with these relations between the southern continents has been 



1 The paper of Borchert (Die Molluskenfauna und das Alter der Parana-Stufe. Stuttgart, 1901) 

 was received after the above was written. The dissimilarity of the Parana and Cape Fairweather 

 faunas is very striking, and the relations between them are still unsettled. 



1 A partial list of animal and plant groups, in which coexistence of allied forms in Australia 

 and South America has been observed, is given by Hedley (1895, p. 3, footnote i). 



