Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1875-01-20


A few definitions OF geological terms may
be interesting before passing Ia other topics
st atifcd rocks occur in layers or beds, called
strata, and the exceedingly thin layers which
they often exhibit are called laminn In
rocks of all kinds it is common 10 find di-
visional planes, either vertical or oblque 10
the planes Of qualification These are called
joints, and enable the quarrymen to work, in
taking out blocks, without blasting. When
strata are inclined, the angle which they
make with the plane Of the horizon is called
the dip. The direction Of the upturned
edges Of strata is called the strike. That is,
If strata dip north or south, the strike is
east and west. When strata dip in opposite
directions they form an anticlinal axis, aud
the appearance Of strata at the surface Of
the earth is called the out-crop. Faults are
a breakage across the planes of stratifica-
ton, permitting the strata to slide up or
down, and are a serious obstacle in mining ;
for when the end Of bed Of coal, or metal,
is reached, the workmen know not whether
its counterpart is above or below their line
of operations.
The disturbances observed upon the earth
are supposed TO be caused by the molten
condition of its interior.
Rocks are also classified as fossliferous
and ndnon-fossiliferous, and all the rocks formed
while the conditions OF the earth were the
same, are regarded as constituting one system
or period. In many places where fossils
abound there are more animals in the rocks
than living upon the earth. Plants are
mostly found in the coal formations, and
animals in limestone. Thirty thousand or
more species have been found, and yet the
work has but just begun These fossils
show that the rocks in which they occur
were once in soft state, like the sand and
mud at the bottom of our present waters,
and each layer once constituted the upper
surface.
The drift, or boulder period is very inter.
esting, for it has left traces all around us
modifying our landscapes, and forming our
hills and wales. Drift consists of materials
derived from all the previous formations
and is in all stages, from finest sand to enor,
nous boulders.
The rocks or boulders scattered over the
surface in North America, have been moved
from the north towards the south. We know
this, because we can find in most cases the
ledge from which boulder was derived, "a
the north of it, but never south of it. We
know they have been moved, because they
are found resting on rocks of an entirely
different structure from themselves. II 1,
common to find boulders, having the outside
grooved, in parallel lines, or marks and
these are undoubtedly the result of theil
having been carried over lodges while fixed
in ice. The general direction of the groove:
is the same as that in which the boulder,
have been transported. Whether the trans
ported rocks, and grooved surfaces, are the
result of ice moving over the surface, a,
glaciers now move or the result of icebergs
drifted over the submerged continent, is still
undetermined. Grooved rocks are found al
great height on the Rocky Mountains, and
not far from the summit of Mt. Washington
also on the Alps, and many other mountains
The markings are more numerous on the
northern than the southern sides OF noun
tains, and the mountains in drift regions Of