xt7sj38kdq4p https://exploreuk.uky.edu/dips/xt7sj38kdq4p/data/mets.xml Shaler, Nathaniel Southgate, 1841-1906. 1877  books b96-12-34907882 English Stereotyped for the Survey by Major, Johnston & Barrett, Yeoman Press, : [Frankfort, Ky. : Contact the Special Collections Research Center for information regarding rights and use of this collection. Geology Kentucky. Notes on the investigations of the Kentucky geological survey during the years 1873, 1874, and 1875  / by N.S. Shaler. text Notes on the investigations of the Kentucky geological survey during the years 1873, 1874, and 1875  / by N.S. Shaler. 1877 2002 true xt7sj38kdq4p section xt7sj38kdq4p 

         N. S. SHALER, DIRECTOR.


                 OF THE


DURING THE YEARS 1873, 1874, AND ,875,

         BY N. S. SHALER.



129 A 130

 This page in the original text is blank.


                   TUCKY SURVEY.

  In the following notes the general scientific work of the
Survey and its most important conclusions will be briefly dis
cussed. It is the intention of the collaborators of the Survey
to bring most of these matters under more extended discus-
sion, in the form of special memoirs or reports. They are
given here with a view to setting forth the nature and progress
of the work under consideration. The problems connected
with the geology of the State will be first discussed, and then
the questions of a more general nature.
  Owing to the fact that the whole of the system of rocks
found in Kentucky lies above the level of the Potsdam sand-
stone, and is practically limited to the Paleozoic series, the
problems in stratigraphical geology are quite limited in their
range, though of very great interest. The questions of a
dynamical character are more numerous and connect them-
selves more extensively with the general geological history
of the continent. The Appalachian system of dislocations is
represented within the State by an extensive series of dis-
turbances. The erosion phenomena of the country are ex-
tensive and varied. and should receive close study. The
question of the origin of the sediments which compose the
rocks of the State present other problems, the solution of
which will aid in the understanding of many of the questions
concerning the past history of this continent.
  It is, however, in the history of the course of organic life
that we find the most noteworthy matters-those which give
the most important and attractive series of facts. In that
history we have recorded the course of events from the time
when this region lay at the bottom of an exceedingly deep sea,




through successive changes, leading to greater and greater
shallowing, until an infirm land was established at the time of
the coal-these great swamp forests, alternating with the suc-
cessive invasions of the sea; after that a vast and unrecorded
time, when the principal events happened on the land, and
therefore want the records of that great historian, the sea.
The changes of life which accompanied these changes of
physical conditions must always afford great problems for the
   In the following pages many of these problems will be
little more than stated, few or none advanced to the point
where they can be regarded as having had their last word.
Not the least reason for their statement is the hope that it
may arouse our students to a sense of their importance:

                           TABLE OF CONTENTS.
CHlAkPrEx  I. Original extent of the geological formations shown in Kentucky. What has
              been lost by wasting action. Inherited topography. Evidences of long
              exposure derived from futmations to the south. Evidence of the same
              from the organic life. Caverns prove no intermediate submersions within
              geologically trodern time. All the valleys of Kentucky clear of recent
              beds. SAhmer ions of the Mississippi Valley, as shown by the Hickman
              beds. Relative greater steadiness of the Leds in the centre of the conti-
              nent. Distributio. of the ancient beds. Age of the Cincinnati axis.
CHAPTER    II. Geological succession of the Kentucky series. Interruptions in the continuity.
              Evidences of great changes. Cambrian series. Silurian series. Devonian.
              Wonderful character of the Ohio shale; its persistency. Waverly series.
              Carb. lime coal measures. Tertiary series. Origin of the sediment of
              thee rocks nearest land.   Means of transportation. The continental
              nuclei. Ocean currents.  The origin of the conglomerates. Siles beds
              and soda beds show granitic origin. Cincinnati series, with its alterations.
              Relatin of changing sediment to migration of life.
CHArrER III. Soil perked of Kentucky. Probably from the earliest Cretaceous times. Ab-
              seice of records like those of the Mauvzajises Ten-es of Nebraska. due to
              greater erosion and absence of lakes. Records of Big Bone and Ohio
              licks. Glacial period of Kentucky. Caverns and caves. Change of for-
              ests. Formation of soils. Classification of soils. Decrease of rain-fl.
CHIArsa IV. Dynamical geology of Kentucky. Subterranean forces. Evidence of constant
              shrinkage of deep lying regions. Cumberland Mountains; their relation
              to the App lachian system. Pine Mountain system. Successive elevation.
              Retreat of escarpments. Pine Mountain of tertiary age. Depressed valleys
              along Pine Mountain. Classification of mountains.
            Cincinnati axis: its successive uplifts. Abandonment as a mountain axiss
              its cause.
            Earthquakes; relation to internal changes. New Madrid earthqunakes



                      CHAPTER I.
  The Kentucky series of rocks, as has already been stated,
extend from about the top of the Calciferous series, which are
the lowest rocks exposed above the drainage of the country,
up to and including the lower half of the Carboniferous series.
In the western part of the State there is a great covered dis-
trict, where we have exposed some beds of a Tertiary deposit,
belonging, doubtless, to a very late stage in the earth's his-
tory, and which is provisionally classed by the Survey as early
Pliocene. Between this carboniferous section and the clearly
exposed beds along the Mississippi river, we have a consid-
erable interval where the beds are mostly concealed beneath
the drainage. In this area, probably at no great depth, we
most likely have several other deposits of earlier Tertiary and
Cretaceous age; below these the Carboniferous system and the
refined beds extend, doubtless,across the whole of the swamp
region, and probably within a few thousand feet, possibly within
a few hundred feet, of the surface.
  The continuity of the Kentucky series was unbroken from
the time of its commencement to the close of the Carbonifer-
ous, and probably later, by any change so momentous as to
bring the condition of extensive dry land within its borders.
After that time of emergence there is no evidence that the
sea ever came to occupy a large part of the State. A general
consideration of the geology of North America shows us that
the Kentucky rocks are only a small and not distinctly limited
fragment of a series of formations which may be termed the
Mississippi series, though they were mostly formed before
that valley had a distinct existence. It will, therefore, often
be necessary to pass beyond the limits of the State in order
to obtain clews to that which may be hidden within its limits.
  Looking into other parts of the Mississippi Valley, we find
that there have been extensive deposits, formed at various
points, which are of a date much later than that of the car-
boniferous limestones, and yet older than the clay beds of the
Hickman series. These beds of the Permian, Triassic, Cre-




taceous, and early Tertiary age, come in as we go either to
the westward, where they all are found covering consider-
able areas, or to the southward, where only the last two series
appear at the surface. The presence of these deposits within
the division of the continent to which Kentucky belongs, may
fairly entitle us to ask whether they had been deposited here,
and afterwards worn away, or whether they were never laid
down over this region. This point has never been carefully
considered; and as its determination is a matter of consid-
erable importance, we will have to discuss it in some detail.
  The first point requiring attention is the fact that this region
is being worn down at a relatively rapid rate. The data for
fixing the precise average down-working of the surface have
not yet been determined, but a study of the facts obtained by
the researches of Humphreys and Abbot for the Mississippi
river will enable us to approximate to a satisfactory conclusion.
The conclusions based thereon are to the effect that the Mississip-
pi discharges from its mouth, in the shape of dissolved mud and
coarser sediment, pushed along by the current on the bottomn,
matter enough to form a stratum one foot thick over the whole
surface of its valley in about seven thousand years. To this
total the several sections of the valley contribute very une-
qually. The rain-fall of the several regions varies greatly,
and the region occupied by Kentucky has at present far more
than the average rain-fall. The data for a very accurate
determination of these points do not yet exist; but enough is
known to enable us to say that, area for area, the Ohio Valley
yields about twice as much sediment as the Missouri Valley;
so that one foot in depth in about three thousand five hundred
years has probably been about the rate of the erosion of sur-
face during the time immediately antecedent to the present
  Nothing in the physical conditions of the earth is so variable
as the rain-fall in particular districts; every uplift and down-
throw of land on the earth's surface, if it be considerable,
must propagate its efforts throughout a hemisphere; but we
may with safety assume, that, ever since the Rocky Moun-





tains were formed, the relative rain-fall of the two regions rep-
resented by the drainage basins of the Ohio and Missouri
has been about the same. Whatever would tend to increase
the rain-fall of the Missouri district would probably tend to
bring up that of the Ohio. There is nothing in the way of
changes in the past, so far as we can see, which could have
tended to lower the rate of rain-fall, and consequently to dimin-
ish the rate of erosion in the Ohio Valley; on the contrary, as
I shall endeavor to show in the fourth chapter, the last re-
cognizable change brought diminished rain-fall, and that for
a period of many thousand years, this region was the seat of
a precipitation far more active than at present. No definite
weight can well be given to this fact; but it doubtless serves
to show that the estimate of erosion given above is probably
not excessive. Assuming, then, that each million years will
take away about three hundred feet from the surface of the
country, the question arises, how much time has elapsed since
the Carboniferous period was completed-the last of the gen-
eral formations of the State. The science of geology has
never attained to that accuracy which will enable us to give
definite answers to such questions; but certain general esti-
mates have been made which probably have a certain value.
Without digressing into a discussion of these methods, we
may say that those geologists, who have attentively studied the
natural records of the earth's surface, would all agree that
the Carboniferous period must have closed at a time certainly
more than ten million, and possibly more than twenty million,
years ago. Without attaching too much value to these esti-
mates, we see that something over three thousand feet of beds
must have been worn away from the surface of this region
since they were uplifted above the sea level. The only way
in which this conclusion can be greatly limited is by the time
to be allowed for the deposition of the beds which have been
lost by erosion. This may much reduce the amount of the
erosion; but it must still leave it probable that a great thick-
ness has first been deposited, and then eroded from this re-
gion, since the Carboniferous time.



  Many reasons concur to make us believe that this additional
thickness of beds was on the whole principally of Carboniferous
and Permian ages. These reasons are substantially as follows:
The greatest single movement of the Appalachians in their
uprising was at the close of the Carboniferous time. Now,
there are many reasons for believing that this extensive flex-
ing of that chain was accompanied by a general uplifting of
the whole continent, or at least that broad western sloping
table-land which lies against the Appalachian Mountain sys-
tem, and is in effect the table-land element of that chain.
Furthermore, the Mississippi Valley, at least its central sec-
tion, seems to have moved tolerably together in its upheavals
and subsidences since the beginning of the sub-carboniferous
limestone. Moreover, in western Pennsylvania, we have a
thousand feet or more of beds, which lie on top of the topmost
part of the Kentucky section, and in the Missouri Valley
we have an extensive series of Permian deposits, which may
well have lain on top of all we have in Kentucky and Penn-
sylvania. These beds may well represent the section which
has vanished in Kentucky, as a consequence of continued
erosion. It is possible that other sets of rocks may have
rested on the top of these-the uppermost beds of the Pale-
ozoic series: but I think it quite unlikely that this part of the
Mississippi Valley has been resubmerged, and the seat of
marine accumulations, except on its extreme western border,
and this only to a slight extent.
  There are in the Southern States, about the Gulf of Mex-
ico, vast deposits of detrital materials, which are probably the
waste from the upper Paleozoic rocks and underlying forma-
tions, of the exposed parts of the continent. Owing to the
peculiar position of these regions, it is difficult to see any
other source for their deposits than this northward-lying sec-
tion of the North American continent. These beds, in their
turn, have been greatly wasted; but enough of their mass
remains to represent some hundreds of feet in thickness of
beds over the whole of the Mississippi Valley.




  There are some peculiar features in the organic life. The
gar-pikes of the Mississippi system of waters, though extend-
ing, it is true, eastward to Lake Champlain, may be regarded
as essentially characteristic of this river system of the central
valley of the continent. This form is fully recognized by nat-
uralists as a relict of an earlier assemblage of life, which was
generally extinguished at the close of the Paleozoic time, and
has only survived in corners of the earth since that time. If
the whole of the water system it inhabits h-ad ever been sub-
merged at the same time, it is reasonable to presume that this
race of animals would have been exterminated. It is, there-
fore, fair to presume that there never could have been con-
ditions suited to the formation of extensive deposits, covering
the whole valley, since the carboniferous period, or thereabouts.
There is another piece of evidence likewise derived from the
organic life of our rivers, but in this case from a group of mol-
lusks. The unionidx, as is well known, have a very extensive
development in the Mississippi Valley, especially in its Ohio
waters. The diversity of species in this section much exceeds
that which we have in any other region; indeed, it seems likely
that there are more species to be found in these waters than
could be found in all the other waters of the world. The only
conclusion to which we can come is, that the group has been
freer from the invasions of the sea in this region than in any
other, and that here, as in the case of the gar-pike, the neces-
sary conclusion is, that the forms have been from a very ancient
date safe from the invasions of the sea; the great lapse of time
having given an opportunity for great increase in the number
and the variety of species. Something of the same nature
may be concluded from the character of our American forests.
Mlany genera, which have existed in Europe during the Ter-
tiary era, have died out there, and only remain in existence
on this continent. This is notably the case with the genera
Liw-iodendron, Liquzidiambar, Nydssa, &c.
  These genera are now peculiar to our Mississippi Valley
and other neighboring forests, but they once flourished over
central Europe. Invasions of water, and probably also of ice,




have served to extinguish these forms there, while in America
they have withstood the dangers of time, and remain little
changed over a great period. This immutability can best be
explained by supposing that this region has remained in great
part unsubmerged.
  The caverned regions of the State are in themselves enough
to assure us that there has been no great submersion of the
region during the last million or two of years. Any such
submersion would be necessarily attended by very great
changes in these wonderful structures. They would probably
become closed to a great extent by marine deposits, while the
superficial marks,which would be made by a short occupation
of a country by the sea, might be effaced by the erosion of a
million of years, or even less. The cavern record ought to
last a good deal longer.
  While denying that the general surface of Kentucky has
been beneath the sea since the Carboniferous period, we are
driven to acknowledge that the western section along the Mis-
sissippi has been so far depressed that it has been able to
accumulate beds, having a thickness of at least three hundred
feet above the level of the river. From an imperfect examina-
tion of these beds, I am inclined to think that they were rather
fluviatile than marine in their character. Yet, I am disposed to
think that they were nearly on the level of the sea at the time
of their deposition. It must also be noticed that inasmuch as
these beds wear with considerable rapidity, the million of years
which must have elapsed since their formation may have been
attended by a loss of over one hundred feet in height. A sea
carried over the country to the height of one hundred feet
above the bluff at Columbus or Hickman, would extend over the
State for a considerable distance to the eastward. By our condi-
tions, it would meet a higher country in that direction, owing to
the loss which has taken place over its general surface during
the time which has elapsed since the close of this subsidence.
It seems likely that the eastward line of such a sea, assuming it
to have been created by a general and not a local subsidence,
would have fallen east of the Tennessee river; and that along




the Ohio and other rivers it should have penetrated some
hundred of miles further. The entire arnd well established
absence in these basins of any such deposits is a striking and
nearly complete evidence of their local nature.
  It is not to be believed that, in the many sheltered nooks,
where they could have been preserved by favoring conditions,
they have all been lost, while in the very line of the Mississippi,
exposed to repeated assaults of one of the most destructive
of streams, they have alone survived. It is easier to suppose
some local and peculiar forms of elevation, acting at this point,
than to suppose the total destruction of all the other fragments
of a great even sheet, except these detached and exposed
masses. There must have been a considerable area of this
elevated country, but it could hardly have had the extension
which we would naturally have expected from its considerable
altitude and its general character. It may be that there is
some connection between the formation of a rather local series
of elevations in this district and the occurrence of strong dis-
turbances, such as that known as the New Madrid earthquakes,
in .8i i-'13. At that time we had in the region of Reelfoot
Lake, as we shall see in the subsequent chapter, a down-sink-
ing of a great district to the amount of ten feet or more. An
uprising similar in its origin may account for these remarkable
insular masses of elevated land.
  It may be well observed, that if these masses had been part
of an equal level plateau, the deposit should have filled up a
large number of the Green river caves, and would have barred
the northward course of the Tennessee and the Cumberland
rivers by filling their valleys. As it is, the supposition that
these Hickman and Columbus ridges are part of an ancient
local elevation, would enable us to account for the fact that
the Cumberland and Tennessee rivers flow so far to the north
and join the Ohio rather than the Mississippi, towards which
the general direction of the drainage should direct them.
Such a barrier may have turned river courses to the north-
ward and maintained them there until their new beds had
been formed.




  The next question as to the prehistoric changes of Ken-
tucky is concerning the original horizontal extension of the
several formations found within the State. An inspection of
the accompanying geological map will make it plain that there
are at present two distinct areas or geological basins, as they
may be called, which lie within the State: one of these is the
eastern coal field, and the rocks which lie below it, and the
other the western coal field and its little-known underlying
rocks. The barrier which separates these fields is the long
low ridge sometimes known as the Cincinnati axis, but which
ranges from the State of Alabama on the south to central or
northern Ohio on the north. This axis has some important
features which throw no little light on the general dynamics
of the North American continent. In a subsequent chapter
its character will be extensively discussed; it is only necessary
for us, in the present connection, to determine when it was
formed and to what extent it separates the region on the west
from the east. The diagrammatic sections in this report will
serve to show its general relations to the rocks on either side.
It will be noticed in the maps, that the several formations of
the State show escarpment faces turned towards this central
ridge, and the student in the field will readily perceive that
these erosion faces are steadily retreating from the central
part of this ridge. He will also perceive that the ridge itself
has certain peculiarities which separate it from all ordinary
mountain ridges. It is singularly wide, being at least fifty
miles across, and very low, not rising more than three to four
hundred feet above the general plain of the Ohio valley.
  A careful study of this ridge has convinced me that it was
begun at a very early day. The beds exposed at the level of
the Ohio opposite Cincinnati show a good many pebbles of
limestone rock imbedded in the limestone and shale. At the
same point, and in the overlying rocks, for one hundred feet
or more of height, the beds show occasional layers of broken
shells packed together as by strong currents. This is espec-
ially noticeable in the beds containing Slrophwroena alterna/t
which occur throughout this section. These facts point to

1 2



the conclusion that these beds were formed in shallow water,
and that this shallow water was swept by strong currents.
Beneath the Cincinnati Group there is an extensive system of
sandstones or other quartzose rock. This is shown by the mat-
ter brought up by boring made near Cincinnati, which I exam-
ined in i868, when, from the depth of two hundred and seventy
feet below the bed of the Ohio river, the auger brought up a
fine silicious rock, seemingly the fragments of an open-grained
sandstone. From this rock, and from the beds just over it,
issue a great number of saline springs, which occur all along
the Cincinnati axis. There is no other way of explaining
these springs save by supposing that they are flowing from
deposits of salt laid down when this region was near the sur-
face of the water, so that great salt marshes were formed, to
which the sea water had but difficult access, so that, by
evaporation, quantities of salt were laid down. These several
facts-the occurrence of salt deposits at one level, pebbles at a
point some hundred feet or more higher, of broken shells at
yet another hundred feet up in the section, and finally of salt
deposits again in the blue-grass limestone, which forms the
summit of the Cincinnati Group-gives us fair reasons to con-
clude that this series of deposits was formed in a region which
was balanced near the top of the ancient seas. On the other
hand, on the east, in the region now occupied by the head-
waters of the Tennessee, the beds deposited at this time were
all made in deep water, without any of the phenomena which
indicate occasional elevation of the bottom to the surface. I
have not personally examined the equivalent beds in Illinois,
but I believe from the descriptions that they likewise fail to
show these alternations of condition which indicate shoal
water. Even the equivalent beds in New York, although
formed near a shore line, fail to show anything like as much
evidence of the successive uplift into land conditions of that
region as is shown about the Cincinnati axis.
  Along with the evidence already cited to show the ancient
character of the Cincinnati uplift, we may cite the extraordi-
nary frequency of sandstone beds at some points in the series,

1 3



particularly at about one hundred feet below the top of the
section. This shows that the shore line probably came near
to this region a number of times when the bottom did not
actually arrive at the surface.
  The Cincinnati series in this section is closed by a sand-
stone, ranging from five to fifty feet in thickness, entirely bar-
ren of organic remains. The history of this rock is not easy
of determination, but it is peculiar to the Cincinnati axis, and
marks one of those sharp transitions which are so prominent
a feature in this section, indicating the rapid successions of
upheaval and subsidence which resulted in giving us a broad
irregular mountain fold traversing the State.
  The existence of recurring upheavals since a very early time
makes it doubtful when this axis of elevation came above the
sea so as finally to interrupt the deposition of strata. It was
at first assumed by geologists that the beds of the carbonifer-
ous and all the underlying strata down to the base were laid
down continuously over the whole of the Cincinnati arch.
More recently it has been announced, with almost equal want
of definite proof, that the elevation has existed from a very
ancient time, and that the eastern and western coal basins
were deposited in areas which were separated by high and
dry land, in this region. In both these conclusions no refer-
ence has been made to the erosion rate of the surface, nor
any attempt to reconcile the conditions of this action with the
theories on which they rest.
  The sections given in this volume show us that the Cincin-
nati Group is continuous over the arch at points where the
cutting is deepest. They further show that the upper Silurian
continues over a large part of the area in a more or less frag-
mentary way: its waste is found on the tops of some of the
highest hills as detached outliers. Above this comes a very
soft formation, the Devonian black shale or Ohio shale, as it
will be called in these reports. The absence of the outliers
of the Carboniferous and Waverly series is, I am inclined
to think, dependent on the softness of this bed, and the rapid
destruction which would overtake outliers which rested upon



it. This accounts for the tolerably continuous front of the
Carboniferous series in northeastern Kentucky, where this bed
is thick, and the increase of outliers in the southern section
of the western front of the eastern coal field, where it is
thinner. The more rapid retreat of the beds away from the
Cincinnati end of the axis than from the region penetrated
by the Cumberland river is, in part at least, doubtlessly due to
the greater thickness of this formation in the region along the
Ohio river, and the consequent more rapid wearing back of
the escarpment. If we allow that one hundred and forty feet
of beds wear off of this region each million of years, then, at
that distance in the past, we had the whole of the Niagara
Group stretching across the arch at Lexington, and covering
almost the whole of the arch throughout its extent from Cin-
cinnati to Nashville. The only sections which would have been
cut deeper would have been the stream beds themselves.
Another million of years into the past would give us the
Ohio or black shale over the greater part of this area. We
would probably have to go something like two millions of
years further back to find the time when the greater part of
the Waverly series still rested on the whole of the summit
of the Cincinnati axis. This is only taking the average rate
of wear for the Mississippi Valley. We have seen that it is
more probable that the rate for the Ohio Valley is nearer
three hundred feet in a million years. On this basis it would
only be necessary to restore the wear which has taken place
during the last two million of years to return to the Cincin-
nati axis all the beds up to the sub-carboniferous limestone,
over the region where now the surface is cut down to the
Cincinnati Group.  The same method of determining the
changes of the past would lead us to conclude that, between
four and eight million years ago, the surface of the country
over the Cincinnati axis lay within the coal-bearing rocks.
There are only two conditions which could essentially invali-
date this reasoning. There may have been other beds laid
over this region which have taken the brunt of the wear,
or the rate of erosion has been on the average less rapid

1 5



than our hypothesis supposes. The first of these objections
seems to me to have little weight, inasmuch as the wide
expanse of country that must have shared this deposit has
failed, on narrow search, to reveal the slightest trace of any
such beds in any of the valleys or other places where it
might have been sheltered from the erosive actions which
destroy the geological records.
  'This absence of even fragmentary remains is always a very
decisive circumstance, tending to show the non-deposition of
any particular beds in any given district. Such non-conform-
able beds are apt to last longer than any single element of a
series, on account of the greater variety of conditions under
which they have been deposited. The other possibility in the
way of the general conclusion as to the beds which have
been eroded is, that the rate of wear may not have been,
on the average, as great as that which has been supposed
in our computations. To this it may be said, that not only
is the time a low estimate, but it may also be fairly con-
cluded that, during a large part of the past, the rate of
wear was materially greater than at present.
  Before leaving our consideration of the Cincinnati axis I
desire to say a word concerning the age of its formation.
We have already seen that during the later Cambrian time it
was in a state of constant oscillation. If the evidence is read
aright in the foregoing pages, these oscillations seem to have
left it, at the