PALEOBOTANICAL EVIDENCE 531 



of the most conspicuous and dominant elements in this flora was the 

 palms, of which there were at least 6 genera and 9 species, some of them 

 being exceedingly abundant in individuals. The 15 species of fig.^ 

 (Ficus), as well as 3 bread-fruit trees (Artocarpus) , undoubtedly argue 

 for a warm climate. Magnolias were also abundant and likewise predi- 

 cate a warm climate, as do the laurels (Laurus) , cinnamons (Cinna- 

 inoinuiii), and related forms. The presence of numerous coal veins, as 

 well as the character and luxuriance of the vegetation, indicates that 

 moisture was abundant, and the known distribution and requirements of 

 the living representatives of the Eaton flora make it more than probable 

 that the climate was at least warm temperate. 



Correlated with the last is the Denver formation of northern Colorado, 

 with a flora of approximately 200 species. The physical conditions under 

 which it grew were apparently the same as for the Eaton flora. 



The flora of the Lance formation of A¥yoming and the Dakotas has 

 not been thoroughly studied, though so far as worked out it is so closely 

 related to that of the Fort Union that for present purposes they may be 

 considered together. The Fort Union occupies a vast area from Wyo- 

 ming and the Dakotas, Montana, and the central Canadian provinces to 

 the valley of the Mackenzie Eiver. It has a flora of some 500 species. 

 Although there are palms of large size in the lower portions of the forma- 

 tion, the bulk of the flora is made up of sequoias, cedars, yews, grasses, 

 sedges, oaks, willows, poplars in great abundance and variety, hazelnuts, 

 walnuts, elms, sycamores in profusion, maples, viburnums in great 

 variety, and a few somewhat doubtful figs. This flora, which is closely 

 similar to that in north Greenland, undoubtedly approached from the 

 north. Notwithstanding the presence of palms, which, however, occur 

 in the lower parts of the beds, the composition of this flora seems to 

 indicate that temperatures were considerably lower than for those Eocene 

 floras already reviewed — in fact, that it was temperate, perhaps what 

 would be called cool temperate. 



In the northern Pacific coast region there are a number of Eocene 

 floras, among them that of the Swauk, which occurs just east of the 

 Cascade Mountains in Washington. This large flora is different from 

 any other yet made known in this country, and consists largely of types 

 that are for the most part found in Central and South America, among 

 them being fan-palms 6 feet in diameter and in layers sometimes a foot 

 in thickness. This shows that the palms were not sporadic or occasional, 

 and indicates, as do many of the other things, that the climate was mild, 

 probably even subtropical. The overlying Eoslyn formation contains a 



