432 Scientific Notices. 
st. That it is stil uncertain if the Chatnical elements of the soil, even if it 
was proved that they are directly depending on the nature of the underlying 
Nyt strata. peetitte a perceptible influence on the vegetation which — 
el pecu ar place. That, in any case, the amount of influe 
the ee renitiear is still pro blem 
2d. ‘That the geological clement viz., the perele Singin 4 from the de- 
Suit paltion of the rocks and entering into the compos of the soil, even if 
eir influence on the veget: atic a ware well marked, ie pa cheba disseminated 
by water and atmospheric agency a great distance from the areas occupied 
by. oy a, from which they come. The lime of a limestone ridge, A 
of a of sandstone are vassied pee the declivities, spread ov 
, kin 7 of rearte transported to the alluvial pains, or Aipa ed on "the 
anks of rivers and thus mixed together in a peculiar compound which, 1 
new state, has but an indirect relation to the ee ie from “hich it . ‘denned 
nd no relat einer to the formations which i Mor r, the 
frequent paar of strata of asaialitinl min of fidlodestis which schlitioee the 
rocks of the great valley of the Mississippi, Silurian, Devonian, og eee 
and Tertiary, prevent an exact limitation of the area over which each of them 
may extend its influence. hagien it has 2 been generally admitted that pissin) 
c 
country than ¢ chemical phnatitae ts of the rocks. Consequently, that the 
direction of the t ike 8, ie amount of light and atmospheric heat and moisture, 
the thickness ue the soil, its hardness and pes for fetaintig water, are 
the essential causes of “the distribution of the plan 
These e brisidetitioné s may be it a they corre wut one side of a com-. 
plex and difficult question which cannot be discussed now. If the hardness, 
i e pl en 
depends principally on the che sina oe of the ge ologicn!: strata. 
other hand, if the dissemination of the geological elements renders the task 
ascertaining t ait) influence difficult in some places, it , fe a reason to 
reject as useless or impossible any attempt to compare the vegetation of a 
country with its geologiea formations. If this comparison can e any- 
where with a chanc success, is vaya in Arkansas, where the strata 
are nearly hetisiintal ind extend over vast a 
he exploration of the Botany of peepee: feaen too late and was se short 
to permit the fulfilling of a work which for its c vegans ould require some 
ontinual research. The Se owine: data collected a ong our ed of 
travel can vhs be considered only as the rst poi — delitatiog lines which 
may be continued and eres hereafter. 
supports, owing to the temperature of the water, pets tes 60 rab 
and the amount of air it is surcharged with. It would be well to know 
what proportion of this air is carbonic acid. The short section on the 
hy of Arkansas is of such general interest that we cite the whole. 
sof Ark. as.—Before entering into the examination of the botan- 
— nd 
iea fiscal fe chinieeed ristic the _part rt of Arkansas which I 
is still a base faeaes qvestion wh 
