Geology of Lee County
In attempting to give the rock formation
of counties, the historian, generally speaking, is compelled to
gather his information from sources not at all reliable, and
naturally that portion of his book is unsatisfactory to himself
and misleading to the reader. How fortunate therefore it was
that I was enabled to secure a reliable as well as learned and
exhaustive treatment of the subject. Ira W. Lewis, one of the
associate editors, discovered the document and referred me to
it. I have copied and embodied it in this work and I may say
with truthfulness that no more valuable information will be
found between these covers than the essay of Doctor Everett.
Dr. Oliver Everett, who came to Dixon in
the year 1836, beyond any doubt was the most learned man who
ever lived in Lee County. In the fifty odd years of active
practice, he came to be beloved by every person who ever met
him, and that acquaintance extended to the four comers of the
county.
Night and day, for over half a century
he rode the country administering to the sick. Nights and days
he traveled, first the trackless prairies, then the muddy roads.
Many times he had driven for forty-eight hours at a stretch
before seeking his pillow. To the rich and the poor he
ministered alike. If the patient was poor his name never found
its way into Doctor Everett's account book and thus a fortune
was scattered over the county of Lee as his contribution towards
building up this community.
In that long and busy practice, he
assisted something like five thousand children into this world,
and it is with pride that I place my name in the long, long list
of children who so early greeted the good old doctor, whose
presence and assistance at such a period was so important.
During such a busy life it scarcely
seems possible that he should find time to delve into the
subject of geology and natural history. But he did and at the
second county fair ever held in Dixon, in 1858, his great
collection of natural history specimens attracted state wide
attention. He also collected a large number of excessively rare
American coins. Where could all of them have drifted? To deposit
them to his memory would have been the appropriate thing to do,
but they were neglected after his death, and now all of his
specimens have perished. But so long as there is any Dixon, the
memory of Doctor Everett will be cherished.
He was an historian of rare merit and
nine-tenths of the old items of our history were snatched from
oblivion and collected by Doctor Everett. The little book of
events, arranged chronologically, and published in 1880, by the
Dixon Telegraph, is a priceless thing. And for it we may thank
Doctor Everett. He and John Moore, long with the Telegraph,
cooperated together in bringing the little book into the world.
He gathered the data and John Moore arranged them. That little
book contains an account of every important event which goes to
make up our history.
Full of years, he passed away beloved by
all and more especially by every member of that great family of
"his children" which he assisted into this world of so many
uncertainties.
From Oregon,
in Ogle County, to Sterling, in Whiteside County.
By the late Oliver Everett, M. D.
Read before the Illinois Natural History
Society, June 27, 1860
My object, in this paper, is to give
some of the results of observations made by me upon the geology
of the Rock river valley, in Lee County, and a part of Ogle and
Whiteside counties, or from about Oregon, in Ogle county, to
Sterling, in Whiteside county. The surface in this part of the
country is much more rolling, or undulating, than in. most parts
of the state. This is particularly the case in the upper portion
of the section alluded to in Ogle county and part of Lee county,
where it is frequently cut up into deep ravines, on the sides of
which the underlying rocks are often exposed to view; and the
banks of Rock river and its tributaries frequently present bold,
perpendicular bluffs of rock, from fifty to two hundred feet
high, thus giving a tolerably good opportunity for geological
investigations. These features are most prominent in the region
of one member of the geological series of which I shall
hereafter speak, viz., the Upper or St. Peter's sandstone. In
another section, where the Trenton lime rock underlies the
drift, there are frequently found deep pits in the ground. These
pits are generally more or less circular, and are from one to
two or three rods in diameter, at the surface of the ground, and
nm to a point below. They are from ten to twenty and sometimes
thirty feet deep, and have, evidently, been produced by the
earth, in these places, falling into and being carried away by
subterranean streams of water in the loose rock below.
Below Dixon, although the surface is
considerably undulating, it is not so abruptly broken by deep
ravines, and the prairies generally slope gradually to the banks
of the river, seldom exposing the rocks at all. Below Dixon
there is very little woodland along the banks of the river,
while above, between Dixon and Oregon, a considerable portion of
the country along the river is covered with timber. The timber
is not generally of very heavy growth, although, in some places,
on the bottom lands, it is quite large. It consists of the
various species of oak and hickory common to the state, the
black and white walnut, the sugar and silver-leaved maple,
box-elder (Negundo accrifolium), sycamore, the red and white
elm, hackberry, ash, linden, cottonwood, etc. The red cedar, the
white pine, the ground hemlock (Taxus Americana), the black and
the paper or canoe birch (Betula lenta and Betula papy-racea) ,
are found on the extreme verge of the rocks overhanging the
river and creeks, beyond the reach of the prairie fires. All
these last mentioned species, except the red cedar, are found,
as far as I have observed, only upon the bluffs formed by the
St. Peter's sandstone.
We should naturally expect to find on a
soil produced from the disintegration of this sandstone, some
plants which are not common to the rich alluvial and clayey
soils of a large portion of the state. Accordingly I have found
several species not included in Doctor Lapham's catalogue, and
some of them not in the additional lists subsequently made by
Doctors Brendell and Bebb, and which I presume are not often
found in other parts of the state. Among which I might name two
species of vaccinium, the Aretostaphylos urauisi, Lupenu
perrennis, Campanula rotundifolia, Talinum teretifolium, Lobelia
kalmii, Cerastium oblongifolium, Linaria canadensis, Fragaria
vesca, and the Viola lanceolate, which grows on the borders of
ponds, or in wet places in this sandy soil.
The drift formation, through this
section, is probably not so thick nor so uniform in depth as in
most parts of the state. There are many things in relation to it
which have peculiar interest, but my object in this paper is to
speak of the rock beneath it.
There is in this section of about thirty
miles of the Rock river valley, a pretty good opportunity to
study several important members of the lower Silurian system and
some of the lowest strata of the upper Silurian series.
Commencing at Oregon, with the St. Peter's sandstone, and
ascending the geological scale, as we go down the river, we find
'the Buff limestone (of Owen), the Trenton limestone, the Galena
limestone, and the shales, etc., representing the Hudson River
group of the lower Silurian system, and the Niagara limestone of
the upper Silurian series.
ST. Peter's Sandstone
The lowest rock which we find in the
section under consideration is the Upper or St. Peter's
sandstone. It is the prevailing rock along the river, from a
mile above Oregon to about three miles below Grand Detour, a
distance of thirteen or fourteen miles. On the northwest side of
the river, I think that in no place does this rock appear on the
surface more than two or three miles from the river. On the
southwest side it extends several miles back from the river. I
should think that the thickness of this rock could not be less
than two hundred feet, and probably more. The country where this
rock prevails is characterized by great unevenness. It is
frequently cut up into deep and sharp ravines, and, in many
places, there are bold, precipitous bluffs, from one to two
hundred feet high. I have not often found these bluffs capped
with the Trenton limestone, as spoken of by Professor Hall as
being the case in Iowa. In many places this sandstone is
interspersed with numerous horizontal bands or layers of iron,
or sand-stone so impregnated and cemented with the oxide of
iron, as to be very firm and resisting. These layers are from
less than half an inch to two inches in thickness, and occur,
one above another, in some places but a few inches, and in
others several feet apart. These layers resist the action of the
atmosphere for a great length of time, and only give away from
the disintegration and wearing away of the rock beneath, when
they break off and fall from their own weight. Between these
layers the rock is sometimes very loose and friable, easily
worked away with the pick.
It appears as if, during the deposition
of this rock, that occasionally, in these localities, the
surface was in some way covered with sediment of the oxide of
iron, which acting as cement rendered this portion of the rock
much harder and firmer than other parts of it. If you will
examine one of these layers with a magnifying glass, you will
see that they are made up principally of the same minute
peculiarly formed grains of quartz, of which other portions of
the rock is composed, stained and partially covered with the
oxide of iron. We frequently find very beautiful ripple marks on
these ferruginous layers. On some of them the impress of the
eddies and ripples of the old Silurian ocean appear as fresh and
palpable as if produced but yesterday. These markings are
sometimes very singular and curious, mimicking the forms of
organized life. Here is a specimen which I have been at a loss
to determine whether it has been produced by the action of the
water or is an impression of some organized being. This rock is
composed of small rounded grains of pure limpid quartz, which
have a singular uniformity in their size and shape, in some
places cohering so slightly as to crumble in the hand, and in
other localities so firmly cemented as to make a good building
stone. This rock is in some places of almost chalky whiteness,
but more commonly it has a grayish aspect, while in other
localities it has a reddish appearance, being stained with the
oxide of iron.
As to the economical uses of this rock.
There are several quarries in the Franklin creek, in Lee County,
and in Ogle County, where it has been pretty extensively used
for building, and cut into window and door sills and caps. There
was a beautiful arched bridge of cut stone, from one of these
quarries, built over Franklin creek, for the Chicago and Fulton
railroad, when it was first constructed. Professor Hall says
that this rock would make an excellent material for making
glass.
It will be perceived that this rock, as
it is found in the valley of Rock river, varies considerably
from the description of it given by Professor Hall as it occurs
in Iowa. Instead of its being uniformly the loose, friable rock,
spoken of by Mr. Hall, with scarcely cohesion enough to enable
him to obtain cabinet specimens of it, we frequently find it
forming bold, perpendicular, and sometimes overhanging cliffs,
with strength and tenacity enough to make a good building stone.
There are places where the rock is flinty and hard, and weathers
out, like granite, in jagged and irregular peaks, high above the
surface of the surrounding country.
Buff Limestone
Next to the St. Peter's sandstone, and
separated from it in some places by two or three feet of shale
and bluish clay, comes the Buff limestone of Owen, classed by
Hall with the Trenton limestone. This is a thick bedded,
compact, semi-crystalline magnesium limestone, in layers of from
one to two feet in thickness. It crops out in many places above
the St. Peter's sandstone.
Between these thick ledges there are
thin shaly layers, an inch or two in thickness, abounding in
fossils. Although those layers are full of fossils, there
appears to be but a very few species. They are very imperfect,
most of them are casts, and appear to be such as are common to
the Trenton limestone proper. This rock is often quite fine
grained and compact, and makes an excellent building stone. From
an analysis of specimens of this rock in Iowa, Professor Hall
thinks that it may be very useful for the manufacture of
hydraulic cement, as its composition was found to more nearly
resemble than any of our other magnesian limestones, that of the
best rocks used for that purpose in other places. These thick
bedded layers are from twelve to eighteen feet in thickness.
Trenton Limestone
The blue limestone of the western
geologists, or the Trenton limestone of the New York survey,
succeeds these magnesian beds. This rock is quite variable in
its appearance. In some places it has a bluish color,
particularly on a recent fracture, but more frequently it is of
a dull buff color. It is not so thick bedded as the preceding
rock, and is in some places quite shaly, and breaks up into
small fragments when quarried. In other places the layers are
compact and thick enough to make a good building stone.
There are vertical crevices frequently
found in this rock, which are from, two to fifteen inches in
width. Sometimes they are filled with debris, and in other
places are open and serve as channels for subterranean streams
of water from the pits in the elevated ground back from the
bluffs, which I have spoken of above. At the base of the bluff,
after a heavy shower, or at the breaking up of the winter,
swollen streams of turbid water may be seen rushing from them.
The Trenton limestone abounds in
fossils. It is the oldest rock in this country in which we find
a great profusion of the remains of organized beings, showing
beyond doubt that the ocean of the lower Silurian era was filled
with a multitude of the lower forms of animal life. Here is a
specimen not much more than twice as large as a man's hand that
has representatives from three of the grand divisions of the
animal kingdom. This central figure is a fine large trilobite, a
beautiful specimen of the Articulata; and here are several
fragments of coral and the stem of an Encrinite from the Radiata,
while the Molusca is represented by several of the Acephala and
a Gasterapod. There are great numbers of Arthocerata found in
this rock. Some of them are of very great size. I have seen
sections of them that were eight inches in diameter. I have a
part of one in my collection which is not more than six inches
in diameter at its largest part that is eight feet in length.
Ammonites of considerable size are found in this rock. Among the
Acephala are several species of Septaena. Strophomena, Orthis,
etc., are common in some of the layers of this rock.
This rock is somewhat extensively used
for building material, although for that purpose it is not equal
in value to the magnesian beds below it. It makes excellent
lime, and is extensively used for that purpose. Some of the
layers of this rock, in this locality, are made up almost
exclusively of fossil shells and corals, and are very compact
and fine grained, and receive an excellent polish, making a very
beautiful figured marble. The Trenton limestone is found
principally in the bend of the river, in the upper part of Lee
county, extending about four miles south, and is also found in a
narrow belt on the northwest side of the river, extending from
Pine creek, in Ogle county, to within a mile of Dixon.
Galena Limestone
The Galena limestone succeeds and rests
upon the Trenton limestone. The line of demarkation between this
and the Trenton limestone is not always easily ascertained.
Layers, partaking sometimes more of the characteristics of one
of these formations and then the other, are often found
intermingled for some distance, although the characteristics of
the mass of the two formations are very distinct. It appears to
be the prevailing rock, underlying the surface of the elevated
prairie, over a considerable portion of the northwestern part of
the state, the streams having in many places cut down through it
into the strata beneath. The Galena limestone is a rock peculiar
to- the West, and is a very important member of the lower
Silurian series. It is important not only from its thickness and
the extent of country which it covers, and the many economical
uses made of the rock itself, but from the rich minerals it
contains, it being peculiarly the lead-bearing rock of the
Northwest, as is indicated by its name.
The Galena limestone is a
coarse-grained, porous, and sometimes friable rock. It has a
dull grayish and sometimes yellowish color and, from its porous
character, weathers out very rough and irregularly. It is
everywhere characterized by its peculiar fossil, the sunflower
coral, the Coscinapora sulcata or recepticalites of Hall. In the
lower beds of this rock there is a very beautiful species of
Favosite quite common. Its pentagonal columns or rather tubes,
filled with transverse lamina of a pure sileceous material,
radiating from a point, present a very beautiful appearance,
particularly on a recent fracture. This coral is often found in
large masses where it has weathered out of the rock, sometimes
entire, but more frequently broken into fragments. Among the
Gasteropods found in this rock are the Marchisonia,
Pleurotomaria, etc. The Orthoceras, Crytoceras, Ammonite, and
some of the bivalves common to the Trenton limestone, are often
found in the lower beds of this rock. This limestone is the
prevailing rock along the river, from a mile above Dixon, to
near Sterling, where it disappears beneath the Hudson River
group and the Niagara limestone. This rock, as may be seen by
the map, spreads out over a much greater extent of country as we
go back from the river, on either side.
Hudson River Group
On the immediate banks of the river,
along the rapids at Sterling, and at the base of the bluffs a
mile above town, on the north side of the river, may be seen the
various rocks, shales, clayey and bituminous deposits described
by Professor Hall as the Hudson River group. The rapids in Rock
River at Sterling seem to have been produced by the wearing away
of the shales of this formation. I have been unable to ascertain
what the exact thickness of this group may be, but think that it
is probably not more than twenty-five or thirty feet. On the map
accompanying this paper I have represented this formation in a
narrow belt, surrounding the Niagara limestone, on the east and
north side.
Although the rocks of this formation do
not appear at the sur-face, except at the rapids and at the
bluff above Sterling, I have been able to trace them, in the
course indicated on the map, by examination of the rocks thrown
up in the digging of wells.
Niagara Limestone
The Niagara limestone is found on the
north side of the river, above Sterling, extending through the
northeastern part of Whiteside County. This rock is also a
magnesian limestone, and resembles, in its composition and
appearance, the Galena limestone. There is a good opportunity to
examine this formation at the quarries, a mile above Sterling.
There it may be seen resting on a green compact rock of the
Hudson River group. The lines of charts common to this rock are
formed there in abundance, sometimes forming layers six inches
thick. The characteristic fossil of this rock, the Catenapora
Escharoides, and a beautiful species of Favosite are common
there. I also noticed a species of Marchisonia and two or three
bivalves. The rock from these quarries makes an excellent
building stone, and is extensively used for that purpose.
[It may be added that in Ashton, Lee
Center, Reynolds and Amboy, there are small quarries, removed
from the river and the creeks tributary to it, the Ashton quarry
in particular furnishing a beautiful building stone. St. Luke's
Episcopal Church is built of it. It is a hard sandstone, and
doubtless of the character mentioned by Doctor Everett. Editor.]
Lee County
History
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