634 E. W. BERRY CEXOZOIC FLORAS OF EQUATORIAL AMERICA 



The exact ages of these various South American Tertiar}^ floras has 

 never been accurately determined. De Lapparent regarded the first as 

 Eocene, probably Sparnacian. Dusen, following Wilckens, regarded them 

 as Oligocene. It is extremely unlikely that they all are of the same age. 

 Those from Colombia, Ecuador, and Peru I am inclined to regard as the 

 same age as the flora from the Isthmus of Panama,® which appears to 

 represent various stages of the" Oligocene plus the Aquitanian and Bur- 

 digalian, and these find their counterparts in the floras of the Catahoula, 

 Yicksburg, and Alum Bluff formations of the United States and in the 

 petrified woods of Antigua and others of the Antilles. 



Part of the Chilean and Patagonian floras appear to be older than these, 

 for they have a few but striking elements in common with those of the 

 lower Eocene of the Mississippi embayment region. Later Tertiary floras 

 from South America not previously mentioned include the Pliocene flora 

 of Bolivia, amounting to 85 species and strictly endemic in character,^^ 

 and a Pliocene flora from the province of Bahia, Brazil, comprising about 

 70 species, some of which are of North American ancestry.^^ 



Summary 



The following somewhat categorical conclusions are indicated by a de- 

 tailed study of the foregoing floras : 



1. There appears to have been free intercommunication between North 

 and South America during the Upper Cretaceous, with the invasion of 

 the northern (Holarctic) flora into all parts of South America and prob- 

 ably to Antarctica. 



2. Continued land connection between North and South America dur- 

 ing the basal and lower Eocene, which, combined with the ameliorating 

 climate of southeastern North America, resulted in the introduction of 

 many new types in that region which were derived from the south. 



3. During the middle and upper Eocene, as well as during the Oligo- 

 cene, there was a continued influx of a few tropical American types into 

 our Southern States, but these were not in sufficient force to demand a 

 land connection between the two regions, nor can it be certain that these 

 types came from South America and not from the intermediate region 

 of Central America and the Antilles. 



4. During the Oligocene there appears to have been a rather free inter- 

 change of plant types between Panama and the Antilles, best illustrated 



» Berry : Op. cit. 



"E. W. Berry: Proc. U. S. Natl. Mus., vol. 54. 1917, pp. 103-164, pis. 15-18. 

 "F. Krasser: Sitz. k. Akad. Wiss. Wien., vol. 112, abh. 1, 1903, pp. 852-860. 

 Ed. Bonnet: Bull. Mus. d'hist. Nat, ann^e 1905, pp. 510-512. 



