The Vermont watchman. [volume] (Montpelier, Vt.) 1883-1911, 1896-04-29
origin OF Pebbles.


barren ridge of this kind, besides fur
nishing him an ideal site for bank barn,
has proved one of the most profitable
patches on his entire farm. Neither Is 1t,
chiefly in the price per load received for
the contents of gravel pit that its prac-
teal value consists, though that may be
far from an inconsiderable item. Though
gravel cannot be used as n fertilizer to in
crease the products of the surrounding
| land, it may add greatly to the value of
such products by making n permanently
passable road leading to n convenient mar
ket This is the purpose for which nature
appears TO have intended It, Not for the
wagon road alone, but for railroad ballast
as well, nothing more satisfactory has ever
| been devised.
AS of the scattered powders, so of these
piled up pebbles, the question must often
| arise, Where did they all come fromP That
| they must have come from various places
is evident, for they are made up of various
kinds of rock. In this respect they resem
BILE the powders, as they do also in their
| worn and rounded shape The chief differ
| enccs are that the pebbles are so much
smaller, are more smoothly worn, incom-
| parably more numerous, more widely dis
| tribute over the earth, and usually found
collected and piled up into ridges or heaps.
| All these characteristics indicate that these
bits of stone have undergone II long process
of grinding and polishing But do we
know of any process of nature by which
this work could have been donep
Yes, we find even now in operation and
open to our inspection three different kinds
of natural mills in which the pebble max
ing industry is still carried on The first
| 20 to 10 icnp ,ill--tna m in which
the powders were shaped. This was evil
dently in ages past aud over certain ex-
tensive regions, the most important of all
agencies employed by nature in grinding
up the solid rocks to pa tces of all degrees
Of fineness But 1t was "a mill without
separator-a sort of preparatory crusher
by which immense quantities of materials
were fitted for the more ready use of other
agencies How this preparatory work was
done may be learned through the samples
still furnished for our observation and
study. Beneath every living glacier of
any considerable extent there is found an
accumulation of rocky material the mass
of which has been crushed and ground to
powder in the form of sand and soil, while
mingled with it are large quantities of
pebbles and other coarser fragments of
rock, ranging in size from cobblestones up
|
finer material is carried onward from the
mouth of the glacier by the outflowing
stream of water, the bulk of all the grist,
both coarse and fine, remains for the time
being where the melting glacier drops it.
The second form of pebble mill is a very
common and familiar one and differs from
the first in that it uses flowing water in
stead of ice In carrying on the grinding
process. Almost everybody has witnessed
1t in operation, though unfortunately
many people fail to have their eyes open
to see and recognize the ordinary processes
by which nature, working trelessly
through countless ages, has accomplished
such extraordinary results. In all regions
except those that are very fit or level the
beds of the streams are apt to be found
covered with pavement of pebbles. The
farther up the stream we go the larger
and more numerous, and also the less
smoothly worn, we find the pebbles These
bits Of rounded rock are not placed in the
bed Of the stream simply to prevent its
cutting too deeply into the soil, though
they do often serve that useful purpose
most admirably. They are kept slowly on
the move. At every time of freshet they
are rolled over, rubbed together and carried
little farther down the stream. In this
way they are ground down year by year
by process so slow as to almost avoid de-
lection, but so ceaseless as to accomplish
marvels when time enough has been given.
To find the place where the rock ma
terial is furnished and the grinding proc
ess begins it will be necessary to follow
, up the stream to its origin, perhaps among
, the mountains or high rocky hills. Here
, we find the mountain torrent frequently
! INSTRUCTED by large angular blocks of rock
| xrbicb haya fa1lpp into itS channel Some
, of these may remain for centuries immov-
, | able by the stream but there are Away
many that are small enough to be tumbled
| downward, especially where the descent is
steep. The pounding, grinding and rub
, bling process thus ever beginning goes
never endingly on. And 1t is often great
ly aided, especially in its upper and earlier
$ course, by the disintegrating action of the
| frost upon the rocks.
/ The third form of mill employed by ma
$ ture in the production of pebbles is very
5 powerful and effective one, and the ont
{ that has been in operation the longest o
all 1t is the waves of the seashore dash
5 ing against the rocks The effectiveness
Of this powerful agent is something almos
incredible. The lashing waves, armed a
5 they usually are with gritty sand, Gu
2 away even the solidest rock. This con
9 slant undermining of the projecting cliff
0 ranged along the more than 100, 600 mile
o of seacoast as we'll as along the shores o
s all the larger lakes results in an incalcula
o BILE amount of broken rock falling in tn
: course of centuries into the waters be
Meath With these loose fragments once a
Y their mercy the waves begin upon them
!. pounding and grinding and washing tina
+ has never been relented since waves ant
s rocks began. The result is the wearing o
t countless millions of rock fragments int
= the smooth and rounded forms to whic
y we give the name of pebbles The pebble
n that have been thus manufactured an
9 heaped up along the ancient seashores ar
what now constitute many Of our grave
# beds, the sea having meantime retreate
Q many hundreds Of miles, 1t may be, froI
o the scenes of its former activity.
l. Simpson in st. Louis obe-Democrat
~ Napoleon and the English Channel.