The prison mirror. [volume] (Stillwater, Minn.) 1887-1894, 1890-12-11
REPORT OF CLASS B.
THE DRIFT.

The science of Geology begins with the surface
materials of our planet. The stones, sands. and
clays which lie upon the surface must
first be considered. Where they came from. what
they are, how they arranged and of what
they to man.
The geological name for these surface materials
is 1.-The Drift" They are commonly known to us
as gravel banks. sand banks. or clay banks as the
case may be- We all know that the drift is the
work of nature, but how many of US have any
knowledge of its formation or its origin?
The drift is northern phenomenon, and this is
borne out by the fact that travel to the
north, find bowl1ers of rock increasing in size
and quantity. while to the south we do not find
them. This distribution is due to the agency Of
temperature. and it must be borne in mind that
temperature sustains the same relation to altitude
as to latitude. Bowlders more numerous in
northern or elevated regions. because the cold is
there more intense.
Having established this theory, we seek to find
out by what agency the powders we're transported
from their northern home. Biologists rule,
hold to the theory of glacial action and this
theory was strongly defended by Agassz. A de-
tailed account of glacier and its action would be
desirable at this point. but it would involve too
much space in a limited report, and we must rely
accumulation of snow that has repeatedly under
gone the process of partial dissolution until
changed into field of ice We can readily per-
ceive to what enormous size they be found;
and there many citations of famous glaciers.
Let your mind revert to the havoc wrought by
the famous Johnstown flood of recent date. and
then contrast the power of that mad rush of water
with the almost incredible force that would &C.
Of q hup oil
in contradstinction, the YOUNGSTOWN flood is a bub-
bling spring beside Mississippi river. 1t must
not be inferred from this however. that glaciers
undergo a rapid dissolution. They move or travel
gradually in a compact mass until they reach
temperature of 32o more. The contrast is
drawn for the purpose of illustrating the force
erted by their movement The theory advanced
is certainly founded good grounds and we
readily perceive that the glacier in its movement
must transport all surface material under or be-
fore it. The transportation of powders is due
therefore. to the relation OF heat and cold.
Let us now direct our attention to the drift as
1t is before our eyes. We see an excavation
through one for the purpose Of making street
Examine the sides and it will be found to contain
layer of sand, then layer of gravel or clay in
terspersed with powders of rock from the common
cobble stone to those almost too large to dispace
This semi-stratlfed drift is common sight but
we do not know how it came here or how it was
formed. Let us travel with the glacier and see
what it will tell In it's grasp see at first
the huge bow ders of rock borne along like a cork
on the water. 1t moves from its northern home
in all its mighty strength to a warmer temper
ature. With each dissolution its force decreases
First the huge bewlder of rock stops in its down.
ward travel account of the diminished force
behind or over it. then the smaller down to
the cobble stones such as we see scattered around
our back yard, until it finds its way to level sur
face and its force abated. The glacier to
exist. and new agency is developed. Biologists
call it 'Torrental action" Let us continue to
follow the water from our dissolved glacier. At
first it forms into many little streamlets, each Of
which causes in its flow some sediment; one
merges into the other, increasing in volume and
force, and so until reinforced by others it
merges into our Missouri river. On it travels. in.
creasng in size until it meets the Mississippi and
empties its water and its constant increase of
sediment into the Father of Waters" Stop and
consider that the Mississippi has also been
inforced by the great Ohio river and that the Ohio
has been built up by the many smaller streams
emptying into it, and we begin to realize the
extent of sedm that finds its way to the Mis-.
sissippi. and finally to the Gulf. 1t is estimated
that river water contains about 80 grains of solid
matter in every cubic foot. We have travelled
from the source Of the Missouri to the Gulf. dis.
lance OF LOO miles. making the longest river in
the world. The sediment empted by the Mis-
sissippi into the Gulf cones from every point of
our great country Many biologists claim that it
is impossible to calculate the amount Of sediment
thus distributed over the bottom of the Gulf but
q. s. engineers have estimated the annual dis.
charge to equal block mile square and PTS feet