St. Charles City Republican intelligencer. [volume] (St. Charles City [Charles City], Iowa) 1857-1861, 1859-08-04
NUMBER 81.

VA itlNOiOIbS3 lIdi obSCi utltHS
show no lack Of moisture in that dis.
trict, the annual precipitation being
fully equal to what it is in the WELL
wooded country farther east in the
same latitude Besides, the growth
Of forest trees is rich and abundant
all through the prairie region, under
certa'~ conditions Of soil and position,
showing that their range is not limit
ed by any general climatologieal
cause.
Taking into consideration all the
circumstances under which the pecu-
liar vegetation of the prairie occurs,
we are disposed to consider the nature
of the soil as the prime cause of the
absence of forests and the predom.
nance OF the grasses over this widely
extended region. And although chem
ical composition may not be without
influence in bringing about this re-
suit, which is question for farther in-
vestigation, and one worthy Of care,
ful examination, yet we conceive that
the extreme finencss of the particles
of which the prairie soil is composed
is probably the principal reason why
it is better adapted to the growth OF
it's peculiar vegetation, than to tho
development of forests. 1t cannot fail
to strike the careful observer that
where the prairie occupies the surface
the soil and superficial material have
been SO finely comminutcd as to DO
almost in the state of an impalpablo
powder. This is due partly to the pc.
culiar nature of the underlying rocks
and the facility with which they un.
dergo complete decomposition, and
partly to the mechanical causes which
have acted during and since the accu,
mutation of the sedimentary matter
forming the prairie soil.
If we go to thickly-wooded re-
gion, like that of the northern PENN.
sula of Michigan, and examine those
portions of the surface which have
not been invaded by the forest, wo
shall observe that the beds of ancient
lakes, which have been filled up by
the slowcSt possible accumulation Of
detrital matter, and are now perfectly
dry, remain as natural rrairics, and
are not trcspasscd on 10y the surround.
ing woods. We can conceive of no
70 .i.It ,SaoG'. tIiaII tut IAtiIhrV
iineness of the soil which occupies
these basins, and which is the natural
result Of the slow aud quiet mode in
which they have been filled up. Tho
sides OF these dcprcSSlons, which were
once lakes, slope very gradually up
wards ; and being covered with
thick growth Of vegetation, the mate
rial brought into them must have been
of the finest possible kind, as is proved
to have been the case by examination.
Consequently, when the former lako
has become entirely filled mp and
raised above the level of overflow, wo
find it covered with q most luxuriant
crop of grass, forming the natural
a meadows from which the first settlers
Q are supplied with their winter store
I of fodder.
: Applying these facts to the case Of
the praires of larger dimensions far.
ther south, we infer, on what seem tn
be reasonable grounds, that the whole
region now occupied 10y the prairics
of the northwest was once an i'm
/
ment of almost impalpablc tineness
gradually accumulated that this ba-
sin was drained by the elevation Of
; the whole region, but, at first, so slow
". that the finer Particles of the SUI
pcrfcial deposits were not washed
away, but allowed to remain where
they were originally deposited. After
the more elevated portions Of the for,
mer basin had been laid bare, tho
drainage becoming concentrated in
: comparatively narrow channels, tho
i current thus produced, aided perhaps
!. by a more rapid rise of the region, ac,
l onircd sufficient velocity to wear
down through the finer material on
G the surface, wash away portion Of
it altogether, and mix the rest so ef'
E fectualIy with the underlying drift
l materials, or with ahradcd fragments
of the rocks in place, as to give rise
) to different character Of soil in the
' valleys from that of the elevated land,
!, This valley soil, being much less ho'
II mogeneous in its composition and con-
{ tanning larger proportion of coarse
materials than that OF the nplands.
a seems to have been adapted to tho
>, growth of forest vegetation and, in
II CONSEQUENCE of this, we find such 10.
e calities covered with an abundant
/, growth of timber.
c Wherever there has been varia,
d ton from the usual conditions of soil
IA on the prairie or in the river bottom,
l. there is corresponding change in
II the character of the vegetation. Thus
e on the prairie, we sometimes meet
n with ridges of coarse material appar,
D emily deposits of drift, on which, from
n some local cause, there has never been
an accumulation of fine sediment IN
y such localities we invariably find q
d growth of timber. This is the origin
IF of the groves scattered ayer the prai-
II ries, for whose il lated position and
y peculiar circumstances of growth we
t are unable 10 account in any othe,
= way.
:; The condition of things in the river
h valleys themselves seems to add to the
e plausiblity of this theory. In the dis
II triet which we have more particularly
examined, we have found that where
?, the rivers have worn deep and com
II paratively narrow valleys bordered by
e precipitous bluffs, there is almost al
ways a growth of forest but wheru
lie the valley widcns out, and the bluffs
ID become less conspicuous, indicating a
rs less rapid erosion and currents of di-
he minshed strength, their deposition
le has taken place under circumstances
al favorable TO the accumulation Of 4