TERTIARY FLORA OF CHILE 117 



gradually shallowing and perhaps becoming emergent during 

 the Aquitanian, followed by a marked transgression in the 

 Burdigalian. At present our chief interest centers in the 

 Fagus zone and its flora. This flora, as described by Dusen, 2r> 

 consists of 29 species, of which the Flabellaria, previously 

 mentioned 'as doubtful, is the only one that occurs in the 

 Tertiary floras already enumerated from South America. 

 The particular fades of this flora is furnished by the abun- 

 dance of Fagacese. This family is represented by two species 

 of Fagus and by 13 species or varieties of Nothofagus. This 

 flora is certainly older than those already mentioned and it is 

 as certainly Tertiary in age. It unquestionably had its begin- 

 nings in the Northern Hemisphere and has also been found 

 to be represented at somewhat similar horizons in Australia, 

 New Zealand, and Antarctica. That it did not migrate into 

 Patagonia from North America appears to be probable from 

 the total absence of any definite ancestral assemblage in the 

 abundantly fossiliferous Upper Cretaceous or Eocene of the 

 latter continent from which it seems probable that it could 

 have been derived. Nor are any traces of it found at more 

 northern localities in South America. The explanation seems 

 to be that it reached southern South America from the oppo- 

 site direction, namely Antarctica. 



A very interesting Tertiary flora has been recently de- 

 scribe'd 2(i from the border of the Antarctic continent on 

 Seymour Island, off the east coast of Graham Land. This 

 flora contains a large element of subtropical or warm temper- 

 ate types like those found today in southern Brazil, and 

 another large element of forms suggestive of the existing 

 temperate flora of southern Chile and Patagonia, and includ- 

 ing species of Fagus and Nothofagus like those found in 

 Patagonia, Chile, Australia, and New Zealand. Dusen, 



25 Dusen, P., Ueber die tertiare Flora der Magellanslander Svenska 

 Exped. till Magellanslanderna, Band I, pp. 87-107, pis. 8-13, 1899. 



28 Dusen, P., Uber die Tertiare Flora der Seymour-Insel. Wiss. 

 Ergeb. Schwed. Siidpolar-Exped., Band 3, 27 pp., 4 pis., 1908. 



