Platanus. AMENTACE^E. 13 



All the other specimens, and they are numerous, represent comparatively 

 small leaves, seven to twelve centimeters long, six to eleven centi- 

 meters broad, all broadly obovate, either gradually or abruptly narrowed 

 to the petiule, with the same character of nervation and of border di- 

 visions as the large one. The nervation is more or less regularly tri- 

 palmate, the primary lateral veins at an open angle of divergence from 

 a distance above the borders, branching outside, and joined to the secon- 

 dary nerves by thick veinlets, mostly simple or crossed at right angles in 

 the middle of the areas. By a slight prolongation of the primary lateral 

 nerves the leaves are obscurely trilobate. The petiole, as seen from 

 Fig. 3, the only specimen upon which it is preserved, is short, bearing 

 at its inflated base two leaf-like obovate, obtusely pointed stipules, hav- 

 inir in a reduced decree the same characters as the leaves. As there 

 is no other reason for considering these leaves as referable to two spe- 

 cies than the great difference in size, and as the same diversity is observ- 

 able in the leaves of the living Platanus occidentaUs, Linn., to which this 

 fossil one is closely related, a separation seems unjustifiable. By the form 

 of its bifid and deciduous stipules, the species is related to P. Lindcniana, 

 Mart,, of Mexico. 



Habitat. — Chalk Bluffs, California. Voy's Collection. All the specimens 

 are from the same locality, and upon the same kind of whitish soft clay. 



Platanus dissecta, sp. nov. 

 PI. VII. Fkj. 12. PL X. Figs. 4, 5. 



Leaves large, subcoriaceous, truncate or subcordate at the base, deeply three or five 

 lobed ; loins narrow, lancto/ate-acaiiiinate, sharply toothed. 



This species is, like the former, closely allied by some of its characters 

 to P. occidentalis, Linn., being, however, evidently distinct by its narrower, 

 more acutely pointed lobes, in an acute angle of divergence to the mid- 

 dle, and by its sharply pointed teeth all turned upwards. As far as can 

 be seen by the branching of the lateral primary nerves in two nearly 

 equal divisions and the acute teeth, Fig. 12 of PI. VII. is referable to 

 the same species as Figs. 4 and 5 of PI. X., though the direction of the 

 lateral lobes differs. Among the specimens from Table Mountain are 

 many fragments, showing the lobes still more inclined toward the middle 

 one, and more acutely dentate. Fig. 5 of PI. X. seems to represent an 



