4 PROCEEDINGS OF THE NATIONAL MUSEUM vol.73 



the existing flora of the Lago Nahuel Huapi district, it shows no 

 certain indications of different temi^eratiire conditions but does seem 

 to indicate considerable more humidity and an environment more 

 like that found at the present time west of the Andes in Chile. If 

 this conclusion is valid, it would mean less extremes of temperature 

 throughout the year as compared with present conditions in Eio 

 Negro Territory. 



The florule from the two localities in the Rio Chalia district of 

 western Santa Cruz Territory includes the following 11 species : 



Adiantum patagonioum. LaureUa amarillana. 



Fitzroya tertiarla. Laurophyllum chalianum. 



Rollinia (f) patagonica. Apocynophgllimi chalianum. 



Hydrangea (?) incerta. Bignonites chalianus. 



Sterculia washhumii. Phyllites sp. 6 (?). 

 Pemmis cJarki. 



Although occurring about 8° farther south, it comprises a much more 

 northern and warmer climate assemblage than the previous florule, 

 Fitzroya being the only species that seems distinctly at home in this 

 latitude at the present time and then only in the wet environment of 

 the Chilean side of the Andes. One species, Pev/tnus clarki, and sev- 

 eral genera are common to the flora described from Mirhoja, Chubut 

 Territory, and point to the present flora as having lived in a humid 

 warm temperate environment. 



INDICATIONS OF AGE 



From what has been said in the preceding paragraphs, both the 

 genera represented and the environment which they indicate point to 

 these florules being of different ages. So much seems perfectly clear. 

 Whether either or both should be considered Oligocene or Miocene is 

 not so clear. The whole general question of the age of the Pata- 

 gonian sedimentaries has given rise to a remarkable diversity of 

 opinion, the principal contributors having been Ameghino, Roth, 

 Gaudry, Scott, Hatcher, Ortmann, von Ihering, Wilckens, Cossmann, 

 Wiman, Windhausen, and Matthew. The statement by the last- 

 named author ^ is one of the most recent and the most useful summary. 



In a recent paper Schiller * mentions well-preserved dicotyledonous 

 leaves near Barriloche overlain by tuffs partly silicified, from which 

 he enumerates 25 species of marine mollusca representing the Pata- 

 gonian stage. From this there is some reason for supposing that 



» Matthew, W. D., in Climate and Evolution. Annals N. Y. Acad. Sci., vol. 24, pp. 

 171-318, 1915. 



* Schiller, W., El Cerro " Ottoshohe " de Bariloche. Bol. Acad. Nac. d. Ciencias Argen- 

 tina, vol. 30, pp. 335-339, 1927. 



