f 



THE PIJOCENE OF EUROPE, ASIA, AND NORTH AMERICA 345 



Flora of the Eastern states. — Lesquereux ^ also described a flora from 

 Oraves County, Kentucky (latitude 37°), which he believed to be of Pliocene 

 age, including the fig {Ficu.s), laurel {Laurus), soapberry {Sapindm), and the 

 oak {Quercus). In the Pliocene of Bridgetown, New Jersey, the following 

 plants have been found: the sweet gum (Liquidambar), laurel, and poplar. 

 One of the earliest of the numerous contributions of the same author is 

 that on the supposed Pliocene flora collected near Somerville, Tennessee.^ 

 This flora finds its relatives at the present time on the southern shores of 

 Florida and islands of the Gulf of Mexico; there are only four jilants refer- 

 able to existing species. It includes the laurel, the wild orange tree {Pru- 

 nus) now found in the Bahamas and near the coast of the Carolinas, the 

 oak of a species now found along the coast of Florida, the beech, a species 

 of more northern range, and the willow. 



Late Miocene or Early Pliocene 



In every branch of life the fauna from northwestern Kansas to Florida is 

 a continuation and evolution of the typical Miocene fauna of North Amer- 

 ica. Perhaps it is Miocene, for there are no new elements. The clawed 

 perissodactyls or chalicotheres are absent or undiscovered, while the oreo- 

 donts (Merycochoerus, Merychyus) are becoming rare ; conditions were either 

 becoming unfavorable for these forms in this region or the entire phylum 

 was dj'ing out. The rarity of the browsing horses is an indication of con- 

 ditions unfavorable to the older brachyodont browsing types ; a few remains 

 of these animals are, however, still found. It is important to grasp clearly 

 the fact that the grazing horses are now in a highly polyphyletic condition. 



The chief formations in which these late Miocene or early Pliocene 

 early types of mammals occur are the following : 



4. Rattlesnake Formation of John Day Valley, Oregon. 



3. Republican River Formation of northwestern Kansas. 



2. Alachua Clays or Archer Formation of northern Florida. 



1. Ogallala Formation (t^q^ical) Darton, of southwestern Nebraska. 



Late Miocene or early Pliocene times in North America were character- 

 ized by the survival of the last members of the great family of oreodonts, 

 which are thus far represented only by fragmentary specimens of the char- 

 acteristic ]\Tiocene genera MerycochoRrus and Merychyus. Among the peris- 

 sodactyls the browsing or forest horses (Hypohippus) still survive but are 

 also becoming rare; they are represented by forms with somewhat longer 

 teeth than those of the Middle Miocene. Of the grazing horses the char- 



^ Lesqiiprovix. L., Recent Doterminations of Fossil Plants from Kentucky, Louisiana, 

 Oregon, California, Alaska, Greenland, etc., with Descriptions of New Species. Compiled and 

 prepared for publication by F. H. Knowlton. Proc. U.S. A^nt. Mus., 1888, pp. 11-38. 



- Le.sfiuereux, L., On Some Fossil Plants of Recent Formations. Ather. Jour. Sci. and 

 Arts., 2d Ser., Vol. XXVII, May, 1859, pp. 359-366. 



