American Lancaster gazette. [volume] (Lancaster, Ohio) 1855-1860, 1858-07-08
For the Lancaster Gazette.
Geology, Number 1.


For the Lancaster Gazette.
Geology, Number 1.
1st. The OHecis of the S;ience.-TLe
science Of Geology treats of the structure,
mineral composition, aud arrangement Of
the rocks which form the crust OF the earth.
Ii treats also of the causes which have form
ed the crust as we find 1t, and which are
still gradually changing tie crust by the
destruction Of the older rocks and the for
nation of new ones. Ii further notices the
peculiar fossils, or remains Of animal and
vegetable subItaaces. by which the r;cks
formed at different periods are character
lied and distinguished from each other.
end. Utility of tile Scieace.-The science
Of geology is Of great practical utility to
the minel in enabling him 10 decide on the
probability of finding certain mineral de,
posts in any given locality, and it is use
Iul TO the agricultuIisti enabling him TO
determine the nature Of the soil of a parties
ula, tract, by an inspection of the rocks
from the disintegratiop OF which the ingre.
dients Of the soil have been derived.
3D. arrangement and General CLASSIC
cation Of RockS.-In the digging of wells
e we usually pass through succession of
: beds Of clay, sand and water.worn gravel.
4 disposed horizontally. live inspect the
stone luarries in the sides of our hills, we
{ shall observe horizontal arrangement Of
o the rocks. The minerfnds that beds of coal
e and iron ore are nearly horizontal in their
a position. II we observe bed of shale or
- slate we shall discover that not only is the
entire bed horizontal, but that the bed
. consists of avast mum er OF very thin hor-
n rizontal layers lying ons above another
, This horizontal arrangement OF entire beds
"a of rock one below another, as well as the
separation Of each bed into thin layers
le by horizontal divisions or seams, is called
d. stratifcation.
We The stratifed rocks have been chiefly
is formed by deposits Of mud, sand and 9th
: er substances at the bottoms of forme
- oceans. That such has been the origin o
CT these rocks is known by the circumstanc
to that in every part of the world, soa she'll
rs. snd other paris OF marine animals are foun
80 depth of thousands Of feet below tie sur
face. .....
y But the .stratiGsd rocks do not exten
IN indefinitely downwards: The aggregat
thickness Of these rocks, nowhere, perhaE
,ra exceeds ten or fifteen miles. The rocl
!, which lie below these are crystalline
'"ee their texture, end present no traces Of bo
as izontal seams. TIE crystalline rocks SOM
ify times make their appearance at the surfa'
ets in the ridges and peaks Of mountains
l. These rocks usually assume the form
w. =. granite. which lis so called from its col
his sistirg Of graiu-like crystals of quartz ar
in feldspar iure,mingled with mica.
ar A third class of rocks consists Of matt
that has been elected from volcanoes. T.
products of recent volcanoes are called
'oNS uas. The pro iucts Of ancient volcano
a are oalledtrop rock The matter of t
,ubt trap rocks is supposed to have been eje'
ed in a melted stale beneath the waters
the ocean.
In Trap rocks are compact and heavy,wh
t. lavas are light aud porous. This diff
dor ence is owing to the circumstances that
49, matter of the trap rocks, while coolir
'"0 was subjected to the vast pressure OF
'ltz- waters Of the superintendent ocean, wh
the the lavas cooled under the moderate pr
G, sure Of the atmosphere. a.
N All GRANTEES are supposed, al some pc
cd or other, to have been also in a state
'lton fusion from heat. Hence GRANTEES, as,w
,ade as traps, and lavas are called .igneous roc
loo, in reference to their having derived tn
= - z q
hey pnon;tas ~ aro also called plutonic roc
from the circumstance Of their hay
been formed beneath the surface of
K on earth. and as ,it,were, within the dom'
lion) of Pluto, tho god of the subterranean
by gions.
r,ed The strati6ed rocks are called oque
:, rocks from the circumstance Of their i
III ing been chiefly formed by the action
ME" water. They are also called n1echan
a boy rocks, from the circumstance Of their c
Upon sistipg of particles and fragments sep
ted mechanically from the igneous and
ANY, der sedimeptary rocks, and deposited
were the mechanical agency Of water.
l, in WERNEl