The Minnesota pioneer. [volume] (St. Paul, Minn. Territory) 1849-1855, 1850-05-23
Communicated for the Pennsylvania Telegraph
Original Sketch Of the History and &c.
ography of Minnesota Territory
EY rR. THOMAS FOSTER
fC0ntinucd.)
{Continucd.)
NUMBER III.
BY rR. THOMAS rosTE


Prairie du Chen, the old French and In
the Mississippi, he presents rs a type OF TIL
rock stralification Of the whole valley norts
of that place; and the different strata art
found To range in this order:
ist. Near the level of the bed of the Mis-.
sissippi is soft chite quartose sandstone:
end. Next above this is an unstratified
limestone, styled the lo,cer magnetism lime,
stone, about 900 feet thick.
Sd. Next over this is soft sandstone
between 40 and so feet in thickness.
4th. Lying Immediately above the last, IS
the buf- f-colored, blue AMI gray fossiiiferou,
limestone, upwards of 100 feet IN thickness;
9th. Gaping the whole at the summit, il
the upper n,agnesian limestone, or lead
hearing rock Of The Mineral poin, and Du+
buque districts of Wisconsin and Iowa.
On ascending the river above Prairie dui
Chen, or going North, the rocks cons.tut-
iug the base Of the hills at the Prairie are
seen higher up OIL the sides of the bluffs,
though the hills themselves retain nearly
the same elevation: the consequence is that,
one after another, the upper rocks thin out
and disappear; and before proceeding many
miles, the to,rer magnesian limestone first
found at the bottom of the hills, is seen ex-
tending even To their highest SUBMITS, while
The ouarioze sandstone next below it, grad
uaily rises, and at last constitutes q principal
portion Of their base.
This general tendency Of the stratifca-
ton To rise gong North, or rather North
east, is interrupted occasionally by local
pitches Of the strata, hy which the beds that
have been observed higher on The hill-sdrs,
as one ascends the river, dip down again;
and the upper beds of rock which had near-
ly run out, again thicken, and constitute rs
before, the priucipal part of the hills.
But aside from these local irregularities,
or pitches. the lower rocks continue 10 ri.e
up as We proceed North, until at Mountain
Island, the sandstone that lies beneath the
io,Oer magnetism limestone, is observed To
form the great body of that hill 70 the height
of 426 feet.
About this part of the Mississippi, or a
few miles below, we have, in fact, the com
Of what in the language Of the
Geologist, Is termed the principal aris Of
the Upper miSsi>sIppi, or geological back
bone, from hence The different rock strata
decline each way-tO the South towards the
Gulf of Mexico, and tn the North, (still
with occasional local unduations or irregu-
larliies RS before mentioDrd,) towards the
Falls of 81. Anthony. That is to saw. that
as you proceed in either direction, North or
South from the rocky back bone, the rocky
strata nearest the surface of the country,
and highest in the bluffs, sink deeper and
deeper, and are replaced 10y other rocks
y ing over them, at the surface: and these
again as you proceed, sink down and are
found upholding a different kind Of rock
strata
Thus, below the entrance To Lake Pepin,
the lo,ce" sandstone spoken Of, constitutes
about $40 feet of the bluff hills, and The
ioacer magnetism limestone $50 feet more.
Immediately over it. AT the great bend OF
that Lake, on the North east side, this low
er magnesian limestone may be seen form
ing perpeniicular wall Of nearly goo feet,
the total height above the LIKE heing 409
feet. THIS is the spot celebrated in Dakota
legions as the Maiden's rock, or Cape de
Sioux. At the head of the LIKE, on the
West side. the same magnetism limestone
forms about l6O feet Of The upper portion
Of La Grange Mountain, at little below
Red Wing, or Reniuicha Village Its base
for upwards of 40 feet, is of the lower
sandstone. Thirteen miles below the ST.
and the lower magnetism limestone extends
from the level of The Mississippi, TO the
height Of 24O feet. But Immediately below
the mouth of the ST. Croix, only low ledges
Of the same limestone rock appear, the bluffs
not rising higher than 10 feet; and at the
mouth il sinks still lower down.
Sill ascending the stream, the strata takes
a local rise, or undulation, SO that three or
four miles above the mouth of the ST. Crox.
the lower sandstone again emerges from be-
meath the water, and is seen for II or fifteen
feet above low water mark. 1t very soon
sinks, however, for at Red Rock, on the
east bank, six or eight miles from ST. Paul,
there are only low ledges Of the io,rer mag
nes,an limestone, twelve feet thick, and not
far beyond this point, j, disappears entirely
from the surface, 20 that before reaching
St. Paul, it is replaced bv the upper ,chite
sandstone that at Prairie du Chien was
noted, No. s, as lying over it.
This sandstone constitutes the base Of the
bluffs at St. Paul and St. Peters, and the
lower I9 feet Of the chute at the Falls Of
ST. Anthony.
Between St. Paul and the Fountain
Cuve,* Two miles above the town, the diff
ferent rock strata dip down, going VI. sire am
at the rate OF % 10 so feet per mile. AT
the last named point, still going up stream,
there is another rise in the strata, at the rate
of about ten feet TO the mile.
Next above this upper sandstone, from
Red Rock to ST. Anthony Falls, there is a
formation Of limestone, disposed of in thin
regular layers. This is called shell or fos-
siliferous Limestone. The lower portion is
the purest limestone Of the Mississippi re-
gi0n Of Minnesota, containing near strty-
tire per cent. Of carbonate Of lime, and
thirteen PER cent. only of carbonate of mag
nesia, and will without doubt afford by burn
ing better lime than any Of the calcareous
rock North Of Lake Pepin. l, contains %
parts more lime, and Is parts lees inagpesia,
than the shell limestone " hIch forms about
eleven feet of the upper portion Of the same
formation Of fossiliterous limestone. The
whole thickness of the shell limestone, up
per and lower beds, is about thirty feet.
The lorcr magnesian l,mestone extends
up the rivers Cannon and VerniIliOn, as far
as explored. The lower sandstone forma.
ton and the magnetism limestone compose
the bluffs Of HoOkah or Root, Miniskah,
Wazi Oju, and Of the St. Peters rivers.
METALLIC ORES OF MINNESOTA.
The rocks of Minnesota, as above des-
.NorE.-somcdmes rniscslled Carvers Cave.