PALEOBOTANY BERRY. 405 



Southern United States at that time, one of the prominent features 

 of the vegetation A\as the abundance of palms, represented by the im- 

 pressions of leaves and much petrified wood. Among the palms are 

 Thrinax, Bactrites, Palmetto; and a well-marked date palm is rep- 

 resented by characteristic seeds. Nutmegs are also represented by 

 fruits, as are the Copaiba gum, the Sapodilla, and the Carapa. The 

 leaves preserved include mangroves, satin wood, citrus, stopper, but- 

 tonwood, canna, sea grape, climbing ferns (Lygodium), and the 

 tropical marsh fern (Acrostichum), cinnamon, and many other 

 tropical types. 



During the Oligocene the climate became cooler and drier. Many 

 modern African and Australian types occur in Europe. In America 

 the plains type of country became prominent in the west as a result 

 of the rising mountain systems. The polar floras retreated to lower 

 latitudes. Along the Gulf of Mexico many tropical types, such as 

 the breadfruit and camphor survived, but were gradually replaced 

 by temperate trees like the elm and hickory, until toward the close 

 of the Miocene the flora became very similar to that of to-day, al- 

 though the species were extinct forms of our familiar genera of 

 mixed hardwoods which ranged farther west in the prairie States 

 than they do at present, and exotic types like the Ailanthus at Floris- 

 sant give testimony to the subsequent lapse of time. 



The Miocene forests of Europe were extensive and contained a 

 greater variety than do those of modern Europe. The floras of the 

 Northern Hemisphere were still largely cosmopolitan, or at least 

 Holarctic, and the Miocene and Pliocene deposits of Europe contain 

 many American or Oriental types, such as walnuts, hickories, bald 

 cypress, magnolia, tulip tree, sassafras, and sweet gum, which sub- 

 sequently became extinct on that continent. 



The Pliocene florally is simply a somewhat modernized Miocene. 

 American Pliocene floras are little known, but include forms like the 

 water chestnut (Trapa), now extinct in the Occident. In Europe the 

 Pliocene was a time marked by the completion of the Alps and great 

 geographical changes in. the Mediterranean region, where the sea 

 margins were densely forested with a great variety of mixed hard- 

 woods, among which many American and Asiatic types were promi- 

 nent, Numerous still existing species, such as the bald cypress, box, 

 maple. 3 7 ew, etc., appear during the Pliocene, plant bearing deposits 

 of this age being especially common throughout Europe. In South 

 America the tropical rain forests of the Amazon basin still covered 

 the present desert region along the Pacific Coast, and the Andes were 

 at least 14.000 feet lower than they are at the present time. 

 136650°— 20 27 



