MODE OF OCCURRENCE OF FOSSIL WOOD. 235 
be seen that there are only two species common to both Chalk Bluffs and 
Table Mountain, but that ten genera are represented at both places. 
Name of Species. Chalk Bowens’. Table Name of Species. Chalk Bowens’. Table 
Blufis. Mountain. Bluffs. Mountain. 
Sabalites Californicus Aralia Whitneyi * 
Betula equalis * “ — Zaddachi ? . 
Fagus Antipofi * “  angustiloba * 
«  pseudo-ferruginea * Cornus ovalis + 
Quercus elzenoides * “  Kellogeii a 
see CONVERA * Magnolia lanceolata * 
“ Nevadensis * “2 Californica £ 
« distincta * Acer equidentatum * 
“  Goepperti * “ Bolanderi * 
“  -Voyana * Tlex prunifolia . 
“ _pseudo-lyrata } ? Zizyphus microphyllus x 
Castaneopsis chrysophylloides , “«  piperoides * 
Salix Californica * Rhus typhinoides ; 
“  elliptica * “  Boweniana ? « 
Populus Zaddachi * «mixta * 
Platanus appendiculata * “ myricefolia * 
«  dissecta * * “ metopioides ; 
Liquidambar Californicum x «  dispersa * 
Ulmus Californica * * Zanthoxylon diversifolium * 
“  pseudo-fulva * Juglans Californica + 
“¢  affinis * « — Oregoniana ? ? 
Ficus sordida * “ _ laurinea * 
« ~ tilizefolia * “<  egregia * 
“ microphylla * Cercocarpus antiquus z 
Persea pseudo-Carolinensis * 
In regard to the geological age indicated by the plants in question, it is 
not necessary to do more than refer to what Mr. Lesquereux has said in 
Part II. of this volume. This subject will come up to some extent again in 
a future chapter; and the supposed influence of the glacial epoch in effecting 
changes in the flora of the Atlantic and Pacific slopes will also be discussed 
in its proper place, after the facts relating to the former presence of ice in 
the Sierra Nevada have been set forth. It is sufficient, at this time, to note 
the facts that the fossil flora of the gravel deposits is entirely different from 
that now prevailing in that region; and that it is considered by Mr. Les- 
quereux as Pliocene, while he admits at the same time that it is related by 
some identical or closely allied forms to the Miocene. 
It will be proper to add some of the most important facts gathered during 
the investigation of the gravel deposits in regard to the mode of occurrence 
of the fossil plants of the Pliocene epoch. The vertical range of these has 
been alluded to, and it may be more distinctly stated that either fossil wood 
or leaves have been found at every elevation, from the lowest to the highest, 
where gravels occur. Even as high as Silver Mountain City, at 7,000 feet of 
