GENERAL CONCLUSIONS. 45 



boldtii, etc.; Salix Califoniica with S. sessiUfolia of Oregon ; S. ellipiica with 

 *S'. capreoides of California; two species of Platonics with P. oceidentalis, the 

 form of the stipules of P. appendiculata, referring it more particularly to 

 P. Kndeniana, which, however, is considered a Southern or Mexican variety 

 of P. occidentalism Liquidambar CaUfornicum with Z. acerifolium of Japan; 

 Convus Kelloggii with ('. Nuttallii of California; Jor cequidentatum with A 

 spicatum ; A Bolanderi with .1. tripartitim and grandidentatvm of the Eocky 

 Mountains; Jiiglans Oregoniam with P. rupestris of the mountains of New 

 Mexico and California, and Cercocarpus antiquns, intermediate in the size 

 of its leaves between C. fothergiUoides of Mexico and C. ledifoUus, now inhab- 

 iting the slopes of the mountains from Colorado to California. Therefore 

 types of the present flora are represented in that of the Chalk Bluffs 

 by fourteen probably identical species, counting Cercocarpus and Jut/Inns 

 Califoniica, and by sixteen more or less intimately related ones, or in a 

 relation more than double in degree of what it is in the Miocene. On the 

 species of this list also, the same remark can be made as on those of 

 the former; they represent most of all true American types. Indeed, of 

 the fifty species of the table, there are none strange to the present North 

 American flora, except the two species of Ficus pertaining to a peculiar 

 division of the genus, predominant in the Tertiary of both continents, but 

 now disappeared, it seems, or merely represented })y F. caricn, everywhere 

 cultivated in an infinity of varieties, and Juglans Californica, the offspring 

 nl' ./. acuminata, apparently the ancestor of -/. rcgin, which is as generally 

 known and cultivated, in Europe at least, as the Fig. I have compared 

 Zanthoxylon diversifolium to Z. tnphyllum on account of the peculiar similarity 

 of its leaves to those of the Brazilian species; but the Pliocene form is 

 as closely related by some of its characters to Z. integrifolium of the Mio- 

 cene of GEningen,, to which, according to Heer, Z. Americanum bears the 

 nearest affinity. Hence it is evident that the general character of the 

 Pliocene Mora of the auriferous gravel deposits is truly North American, 

 <>r that it is most nearly related to that of the present epoch. 



The assertion, however, does not apply to the present flora of California, 

 where none of the more predominant genera recognized in the Pliocene 

 plants are represented. Fagus, Quercus (of the subdivision of Q. lircns, 

 Q. castanea, and Q. lyrata), Liquidambar, Hums, Persea, Magnolia, Acer (the 

 section of .1. spicatum and ,1. rubrum), Tkx, Rhus (with pinnately divided 

 leaves). Zantlwxylum, are all generic divisions amply represented in the 



