Iowa County democrat. [volume] (Mineral Point, Wis.) 1877-1938, 1895-08-15
ORIGIN OF PEBBLES.
HOW NATURE MADE THE WORLDS
BEDS OF GRAVEL.
Three Different Kinds of Natural Mills
Which Carry on the Industry Flowing
Water, Grinding Ice and Dashing sea
Water ut Work Upon Masses Of Rock.

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bed, and yet many farmer has found That
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 it,
chiefly, in tho price per load received for
the contents of a gravel pit that its prac-
teal value consists, though that may be
far from an inconsidorable item. Though
gravel cannot be used as fertilizer to in
crease the products Of the surrounding
land, 1t may add greatly to the value of
such products by making a permanently
passable road leading to a convenient mar
ket. This Is tho purpose for which nature
appears to have intended 1t. 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
ences arc that the pebbles are so much
smaller, are more smoothly worn, incom-
parably more numerous moro 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 q 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 tho pebble max
ing industry Is still carried on. Tho first
of these Is the Ice mill-the same in which
the powders were shaped. This was evi.
IDENTIFY In ages past and over certain ex-
tensive regions, the most important of all
agencies employed by nature In grinding
up the solid rocks to particles Of all degrees
Of flneness. But 1t WAS n mill without a
separator--a sort of preparatory crusher
by which immense quantities of materials
were fitted for tho 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 tho mass
powder In the form Of sand and soil, while
mingled with 1t are large quantities OF
pebbles and other coarser fragments of
rock, ranging in sizo from cobblestones up
to enormous powders. While part of tho
finer material Is carried onward from tho
mouth Of the glacicr by tho outlowing
stream Of water, tho bulk Of all tho grist,
both coarse and fine, remains for the timo
I, lao, a
Tho second form Of pebble mill is u very
common and familiar one and differs from
tho 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 Dyes open
to sec and recognize the ordinary processes
by which nature, working tirolessly
through countless ages, has accomplished
such extraordinary results, In all regions
except those that are very fit or Lowell the
beds of tho streams AFRO apt to he found
covered with i pavement Of pebbles, The
farther up tho stream we go tho larger
and moro numerous, and also the less
smoothly worn, wa find the pebbles. These
bits of rounded rock are not placed In the
bed of tho stream simply to prevent its
cutting too deeply into tho soil, though
they do often servo that useful purpose
most admirably Thoy arc kept slowly on
the moNo, At every time of frcshct thoy
arc rolled over, rubbed together and carried
n littlo farther down tho stream. In this
way they arc ground down year by year
by process SO slow MS to almost avoid de-
lection, but So coasecss rs to accomplish
marves when time enough has boon given.
To find tho place where the rock ma
torial is furnished and tho grinding proc
oss begins II will be necessary to follow
up the stream To its origin, perhaps among
the mountains or high rocky hills, Hero
we find tho mountain torrent frequently
obstructod by large angular blocks of rock
which have fallen into its channel. Some
of these may remain for centuries immov-
able by the stream, but there are always
many thaG are small enough to be tumhlcd
downward especially where the descent is
steep. Tho pounding, grinding ana rub
bling process thus oyor beginning goes
never endlngly on. And it is often great
ly aided, especially in its upper and earlier
course, by tho disintograting action of tho
frost upon tho rocks
The third form Of mill employed by ma
turo In the production of pebbles Is II very
powerful and effective one and the one
that has been in operation the longest of
all 1t is tho waves Of the seashoro dash
Ing against tho rocks. Tho effectiveness
of this powerful agent is something almost
incredible, Tho lashing waves, armed as
they usually arc with gritty sand, out
away even tho solidost rock, This con-
slant undertaking OF the projecting cliffs
ranged along the moro than 100, 900 miles
OF seacoast ms we'll as along the shores Of
all tho larger lakes results In an incalcula'
BILE amount of broken rock falling in the
course of centuries into the waters be-
meath. With these loose fragments once Mt
their mercy tho waves begin upon them
pounding and grinding and washing that
has never been rocnted since waves and
rocks began. The result Is tho wearing Of
countless millions of rock fragments into
the smooth and rounded forms to which
we give the name of pebbles The pebbles
that have been thus manufactured and
heaped up along the ancient scashores arc
what now constitute many Of our gravel
hNds thu Saa hayinu meantime rptrentpi