The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1903-12-29
MANY GIANT VOLCANOES.
Prairies of Minnesota Built Up on
Beds of Fiery Lava of Ages Ago.

New 1Ork sun.
Most of the natives of Minnesota have
never seen a mountain. When they first
come east over the Appalachians the great
hills a wonderful and inspiring revela-
ton. Their own State has few groups of
conspicuous hills and many bluffs along
the Minnesota and some other rivers, but
as whole the State consists of undulating
prairie land.
The ordinary observer would never sus-
pect, what is fact, that the territory now
occupied by Minnesota was formerly shak-
en- by tremendous eruptions from volcanoes,
whose necks or conical mounds cannot now
be even found, or that it had towering
mountains which have been worn down I'M
I'll only their f1attened stumps remain. But
biologists tell us that the Minnesota noun
tains We're once high and grand.
These facts were not discovered until re-
cent years, since the geological survey of
Minnesota was organized. The scientific
men of the survey have made very care
1ul study or every part or the State and re-
vealed the wonderful story of the ancient
land.
Professor c. w. Hall, who occupies the
chair OF geology and mineralogy in the Uni
versity of Minnesota, tells us in a book he
has just written that the volcanic phenom-
ena or Minnesota were, in their time, on
scale more magnificent than even in Italy,
Hawaii and the Philippines, where. as we
know, tremendous masses of lava have been
poured out of craters to cool as basalt. The
lava streams of Vesuvius cover only pal
try few square miles; only 1900 square miles
OF Hawaii are covered with volcanic out
pouripgs. But in Minnesota, as Professor
HallesrelateS, over 800 square miles are
"overspread with rocks as dark in color and
as genuinely volcanic as are those of Vesu-
vius or Kilauea. and thousands of square
miles carry more GRANTEES and other rocks
that tell the story of stupendous action long
geologic ages ago.
The region Of Minnesota has many times
been shaken by volcanoes. Four periods of
eruptive activity may be counted in the
rocks as one walks the streets of Duluth.
Six or seven lava flows are recognized in
walking from the mouth of the St. Croix
river UP through the streets of Taylors
Falls, which stands on its banks. The
town of Chengwatanna stands on site
where at least Sixty-five separate sheets
of lava may be counted.
The city of st. Cloud. on the upper Mis-
sissippi. is surrounded by rocks that were
fused and thrust to the surface by tre
mendous earth forces. Along the north
west shore of Lake Superior were a series
of ancient volcanoes that poured out enor-
nous lava flows, built up beds of vol
canic ashes or injected molten material as
broad bikes within the older rocks
We know that the crust of the earth is
continually moving up and down, so slowly
that any appreciate change in level may
not be revealed for centuries. These
changes of level may best be observed
along the margins of the sea, and we know
that a part of our Atlantic coast is now
very gradually sinking while parts of the
scandinavian coast are rising.
The Minnesota biologists tell that
parts OF the state are gradually sinking
The Root river, for example. seems to be
slowly sinking about its mouth. The geolo-
gists infer this because hundreds of acres
of marshy land have been formed around
the mouth and along the lower part of the
river.
Having dropped to a little lower level.
the river of course, has lost impetus near
the place where il joins the Mississippi
and so the silt it carries has dropped with
in its own food plain, forming the marshes
that are gradually growing. 1t is also be-
lieved that the Mississippi river is slowly
sinking about it's headwaters.
If this proves to be a fact the navigable
stretches of the Mississippi above Mime
apolis will become less useful, because the
slowly flowing waters will load the bed of
the river with detritus and make 1t less
available for transportation.