xt7wpz51gn9c https://nyx.uky.edu/dips/xt7wpz51gn9c/data/mets.xml Kentucky. State Geologist. 1887  books b97-20-37310161 English J.D. Woods, Public Printer and Binder, : Frankfort, Ky. : Contact the Special Collections Research Center for information regarding rights and use of this collection. Coal Kentucky.Crandall, A. R. (Albert Rogers), 1840-   . Report on the Pound Gap region. Hodge, James Michael, 1850-   . Preliminary report on the geology of Letcher, Harlan, Leslie, Perry, and Breathitt counties. Hodge, James Michael, 1850-   . Preliminary report on the geology of the Lower north fork, Middle and South forks, Kentucky river. Preliminary reports on the southeastern Kentucky coal field  / by A.R. Crandall and G. [i.e. J.] M. Hodge, assistants. text Preliminary reports on the southeastern Kentucky coal field  / by A.R. Crandall and G. [i.e. J.] M. Hodge, assistants. 1887 2002 true xt7wpz51gn9c section xt7wpz51gn9c Maps and Charts for Kentucky Geological Survey
Publications, Series 2, Miscellaneous Reports, Volume 6

Map of the Eastern Kentucky Coal Fields is filmed after the cover title of A.
R. Crandall's and G. M. Hodge's Preliminary Reports on the South Eastern
Kentucky Coal Field.

Map of the Eastern Kentucky Coal Fields is filmed after the cover title of A.
R. Crandall's and G. M. Hodge's Preliminary Reports on the South Eastern
Kentucky Coal Field.

Preliminary Map of South East Kentucky is filmed after the Map of the
Eastern Kentucky Coal Fields which follows the cover title of A. R.
Crandall's and G. M. Hodge's Preliminary Reports on the South Eastern
Kentucky Coal Field.

Geographical Distribution of the Iron Ores of the United States is filmed
after plate xxx in A. R. Crandall's and G. M. Hodge's Preliminary Reports
on the South Eastern Kentucky Coal Field.

Map of Washington and Marion Counties is filmed after Appendix A in W.
T. Knott's Report on the Geology of Marion County.

 







GEOLOGICAL SURVEY OF KENTUCKY.

       JOHN R. PROCTER. DIRECTOR.



PRELIMINARY



REPORTS



ON THF.



SOUTH-EASTERN KENTUCKY


       COAL FIELD.

                :BY

    A. R. CRANDALL AND G. M. HODGE
              A SSISTANTS

              1887



6VWtI  tEII W'R TUB gaKBT BY JOHN DP, WOOa , PuLsc ritl.R1   AND fINI, FRANKFORt, KV.

 
                                                                    A



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SOUTH IAW XENTUC"
    AND-Il. NOTL or  -nlxSO 1ESRE

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GEOLOGICAL SURVEY OF KENTUCKY.

         JOHN R. PROCTER, DIRECTOR.



            RE  P 0 IT, r

                  -ON THE-


POUND GAP REGION.



BY A. R. CRANDALL



ZLECTROTYPID FOR THI SURVEY BY JOHN D. WOODS, PUBLIC PRINTUR AND BIWDIR, PRANKXORT, KY.

 This page in the original text is blank.

 










INTRODUCTORY LETTER.



John R. Procter, Director Kentucky Geological Survey:
   SIR: In submitting the accompanying report on the Pound
Gap Region, and also the report of Assistant J. M. Hodge, in
extension of the same, it seems hardly necessary to recur to the
difficulties which have occasioned delays in the publication of
the results of field work in the upper counties. Perhaps it is
sufficient to say, that while endeavoring to make the best use
of the limited time available for field work, I have very fully
shared in your desire to avoid hasty conclusions, and this espe-
cially in a field so important as this proves to be, and one of
which so little was previously known. There still remains some
uncertainty as to the place in the general section of some im-
portant beds. As to this, it may be hoped that work in adjoin-
ing localities will supply the data for more satisfactory solutions
of such stratigraphical problems.
   The discussion of the dynamic geology of this interesting
region is limited to the requirements for an intelligent view of
the economic geology of the mountain region.
   Finally, it has been the aim of the writer, by the aid of
diagramatic sections and of photo-engravings, to place in com-
pact form before the reader much that is of special interest as
relating to this field.               A. R. CRANDALL,
                     Assistant Kentucky Geological Survqey
   LEXINGTON, Ky., June 15, 18&I.

 






























































"BREAKS OF SANDY" BELOW TOWER ROCKS.

 









     REPORT ON THE POUND GAP REGION.




   The mineral resources of the upper counties are represented
chiefly by the beds of coal which, to the number of from six to
eight, are found in workable thickness. Enough is now known of
this region to warrant the statement that nature has made ample
compensation for remoteness from established lines of traffic in
both the quality and the quantity of the coal deposits. This
will be seen from the sections and analyses accompanying this
report. On the other hand, a report on the iron ores must be
disappointing, so far as any expectation of large deposits in the
coal measures may have been indulged. (See Introduction,
page 3.) Reports on the lower counties show an increased
leanness in iron ore deposits towards the headwaters of
both the Kentucky and the Chattarawha or Big Sandy
Rivers.  So far as known Pike and Letcher counties are
no exception to this tendency, excepting only a narrow belt
on the face of Pine Mountain, where, along an extended fault
line, ore bearing rocks below the coal measures are brought to
the surface. These ores will be described in the proper con-
nection.
                     TOPOGRAPHY.
   The Pound Gap region presents some topographical features
which in the lower counties are entirely wanting. These fea-
tures are the accompanying results of the violent movement at-
tending the formation of the fault-ridge known as Pine
Mountain.
   So bold an escarpmelat, extending for nearly one hundred
and forty miles across the country, could not fail to give to the
adjacent topography many characteristics, of which the
mountain itself is the best exponent.

 

ft.



REPORT ON THE POUND GAP REGION.



   The greater elevation of this mountain barrier, and the ab-
tuptness of its face, formed by uplifted rocks along an extended
line of fracture, appears at first approach more like an inter-
tuption of the topography of the country by the uplifting of a
barrier across it after its hills and valleys had been carved out
and its drainage established, than like a part of the general
result of the erosion of the whole country after the formation
of this fault-ridge. Doubtless there is a considerable margin of
fact on the side of this first impression, as will be seen by a
comparison with the Cumberland mountain. But the time of
the formation of this fault-ridge-is probably so little removed,
comparatively speaking, from the time of the upheaval of the
coal measures as a whole to form a permanent part of the conti-
nent that it may at least be regarded as a prominent factor in
the determination of the drainage before the river systems of
to-day were mapped out around it.
   From the time of the uplift to the present, Pine mountain
has not been less prominent as a mountain barrier than it is
to-day. And the drainage of this region has adjusted itself to
this prominent feature, making extended detours along the foot
of the mountain slope to find outlets to the westward with the
general slope of the country. Along the face of the mountain,
also, the valleys have fallen into line with the fault, as in the
instance .of Elkhorn Creek, of the Kentucky River above Whites-
burg, and of the heads of the streams in the southwestern part
of Letcher county, the same parallelism continues along the
whole face. Away to the westward and north the drainage con-
forms in general to the slight inclinations of the rocks of the
coal measures, which illustrate by varying dips, some of the
minor movements attending mountain-making.
   Pound Gap is at the head of important branches of two great
rivers, the Kentucky and the Chattarawha or Big Sandy, which
flow in widely different directions, in consequence of the slight,
but well defined anticlinal, which extends from the Gap west-
ward. (See on accompanying map the direction of inclination
as indicated by arrows.) For this reason Pound Gap, though
only cut deep enough for a tolerably good wagon road, is an
important point in this long mountain barrier. With the devel-
opment of railway systems to the Ea4 and South, it will become

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Aalae A.

 


REPORT ON THIE POUND GAP REGION.



a more important point of convergence, especially from the val-
leys of the Kentucky and the Licking rivers, which have for a
separating watershed the extension of the Pound           Gap anti-
clinal, as above described.
   Pine mountain extends as a fault-ridge from the Breaks of
Sandy, in a general southwest direction, to the Elk (Gap, in Ten-
nessee, with but two water gaps in the intervening distance, or
three in all, including the Breaks. The relation of Pine moun-
tain to the Black and Cuniberland mountains, to the southeast,
gives additional importance to Pound Gap, as a possible outlet
in that direction. The average height of Pine mountain above
the drainage on the northwest is, in Pike and Letcher counties,
about 1,600 feet. The southeast slope is about 200 feet less.
Some notion of the prominence of this ridge is given by the
view up the Kentucky river from Whitesburg. (See Plate A.)
Also the view at the mouth of Elkhorn creek.
   The termination of the Pine mountain fault, at the Breaks
of Sandy, gives to the northeast of this ridge the character of
an anticlinal, of no great prominence in the general topography
of the region, but still an uplift sufficient to place the upper
portion of the conglomerate formation above the drainage, and
so to give to the country along its axis the peculiar cliff and
gorge topography of this formation. In this character it extends
across the country to the Tug Fork of the Big Sandy river, and
into West Virginia.
   The rocks exposed in the Breaks are all of the conglomerate
formation at the base of the coal-measures, and there is shown,
by comparatively slight displacements, little of the effects of the
Profound fault, which, within three miles to the southwest, rep-
resents a displacement of not less than 2,000 feet.
   Froni the Breaks of Sandy to the Pound Gap or Sounding GSp, as it is some-
times called, the Pine Mountain is known by many as the Cumberland Mountain.
This is but one of the instances of confusion arising from local nomenclature. The
two rid "es, the Pine and the Cumberland, are joined near the Pound Gap by a Black
Mountain ridge, separating. the waters of the Pound Fork of the Sandy river arid the
Powell river on the one side from the Cumberl knd waters on the other. Along this
ridge the State line crosses from the Cumberland to the Pine Mountain; but the dis-
tinction in both the geology and topography of the several ridges is fully preserved.
the Pine Mountain having aI westward and the Cumberland an eastward escarpment
throughout.
   With equal confusion of the geography of the country the northeast extension
of the Cumberland mountain is called the Stone mountain.
   With the introduction of accurate topographical maps, it may be hoped that cor-
rect notions of the geography of this region will prevail.



7

 


BWOXT ON THIE POUND GAP REGION.



   Little time has been found to study in detail the effects of
this sudden change from an anticlinal to a fault-ridge, or the
conditions attending the formation of the water-gap at this
transition point. The northwest dip of the anticlinal extension
of the mountain beyond the Breaks is preserved to some extent
along the face of the fault-ridge southward, giving a considera-
ble area along Elkhorn creek and to the west, in which the con-
glomerate formation and the comparatively barren shales above
form the bases of the hills. The fall of the Elkhorn and Shelby
creeks is such that these rocks rapidly fall below the drainage
towards the headwaters. (See sections, Plate IV.) The moder-
ate dips, westward from the Breaks, do not fully account for the
sudden disappearance of the massive conglomerates which form
the walls of the Breaks, as noted along the Russell Fork. No
fault has been observed crossing the gorge; but it is probable
that one exists for some distance north of the Breaks, but to
the westward of the line of the main fault.
   The Breaks of Sandy, though now almost inaccessible, will,
with the advantages of railway transportation, become a point
of great interest as an unusually attractive mountain gorge.
Plate B. shows something of the character of the Breaks below
the towers, which rise to a height of nearly 1400 feet above the
river.
   The geology of Pine mountain is not complicated by any
considerable variation from the simple fault-ridge type of
mountain. The average dislocation, by the upthrow of the
whole series of rocks, to an unknown depth along the fault
line, is about 3000 feet. The rocks exposed in the face of
the mountain reach downward and backward in time to the
Upper Silurlan formation. These lower rocks offer little of
economic value for the present, except the iron ores, which will
be noticed in their proper place. But they offer important
testimony relating to the history of Pine mountain. The form-
ations represented are in the same order as noted along the
outcrop of the coal measures. (See report of Lesley on western
outcrop of the coal measures, Vol. IV, old series; also report
on the geology of Menifee county, Part 4, Vol. a, new series,
and other reports by the writer.)



a

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w,

 


REPORT ON THlE POUND GAP REGION.



   The following table shows approximately the thickness of the
several formations:
               Western Oatcrop.                   Pine Mt. Region.
     Upper Silurian rocks, 100 to 200 feet .................................... 400 feet.
     Devonian (black shales) 65 to 120 feet ................................. 150 feet.
     Lower Carb.  Waverly (Gr., 300 to 600 feet .......................... 200 feet.
                Sub-Carb. Limestone, 20 to 400 feet ................ 500 feet.
     Carb. Congi. Sandstone, 10 to 300 feet .................................. 2000 feet.
     Measures above the Congl................................................ 2300 feet.
   It is interesting to note the changes in thickness as indicated
by this tabular view. Up to the beginning of the Carboniferous
proper there is nothing along the mountain axis, as now known,
to distinguish it from the wide stretch of rock-forming area on
either side; certainly not to the northwest. The thickness of
the Sub-Carboniferous Limestone to the east and south is im-
portant as indicating a northwest limit to this area, and also as
representing in retreat from this limit a long continued period of
comparative freedom from most of the disturbing conditions
which interfere with the life of a moderately deep sea.
   During the formation of the Upper Carboniferous series, the
limit of this area appears to have been little changed. But the
conditions attending the distribution of rock-material was so
modified, and the deposits so accelerated along a subsiding axis,
that there begins from the first a distinct history of the belt,
which with the subsequent upheaval, and with the ages of
erosion which have followed, is now represented by the mountains
upon the southeast border of Kentucky.
   It is understood that the great thickness of rocks along
mountain ranges is no mere coincidence; but, on the other
hand, that the great accumulation of rock material upon the sea
floor along an extended axis, carries with it the antecedent
conditions for mountain making. These mountains are, there.
fore, as indicated by this tabular view, Carboniferous in a wider
sense than is comprehended in the mere time of final upheaval
to form a part of the continent. Pine Mountain as a fault-
ridge, niust, however, be regarded as having its origin later than
the Carboniferous Age.
   The original thickness of these rocks at the present outcrop would be the thick-
ness that has been worn away, as also tje original thickness in the Pine Mountain
region would be 2300 feet with the thickness removed.by erosion added. No reliable
estimate of extent of the erosion in either locality can be made as yet. It is probable
that it has been greater along the border of the coal-fields, but not enough to indicate
an approach to the thickness in the upper country.



6

 


0REPORT ON TIlE POUND GAP REGION.



   The first stage in the history of these mountains was also a
part of the history of a wide and shallow channel of the sea as
formed by the older mountains of North Carolina on the one
side, and by the Kentucky Anticlinal of the Silurian Age, ex-
tending through what is now Central Kentucky, on the other.
   This is not the place to discuss the actual limit of the Carbon-
iferous deposits westward, or the possible connection of the
Eastern with the Western coal-fields across the Bluegrass region
by coal-bearing rocks, which may subsequently have been worn
away. That which is of importance in this connection, is the
fact that to the northwest, as also probably to the southeast,
from the line of thickest deposits and of the greatest successive
subsidences, these movements and these deposits were evidently
less and less towards an axis of little movement and of minimum
deposits during this part of the history of the coal-measures.
This, with the ordinary variation of conditions over so wide an
area, will serve to explain the want of similarity between the
sections in the lower counties and those of the Pine mountain
region. It is not unlikely that, conforming to the shortest
distance to the southeast sea shore, a much more rapid thinning
out should be assumed to have facilitated the wearing away of
the whole Carboniferous series beyond the crest of the present
Cumberland mountains.
   The accompanying profile section of the Pine, the Black and
the Cumberland mountains show the order of geological form-
ations in these mountains, and for the Pine mountain substan-
tially the relation of beds to the drainage throughout its length.
There is also shown some interesting facts in the later history of
these mountains. Whatever the fact may be as to the axis of
these mountains, as indicated by the line of the greatest Carb.
deposits, it is evident that the Cumberland mountain represents
the line of final uplift, so far as it is now represented by
Carboniferous rocks. 
   But the crest of the Cumberland mountain has been carried
back several miles from this line of upheaval, while the Pine
Mountain has receded but a little from    the fault-line which
   Therc are some reasons for supposing that this anticlinal, along which in this
region only Silurian rocks are now exposEd has an earlier origin than the close of the
Carboniforous Age. This is not, however, the place to discuss this point, it being in
no way essential to the purpose of this report.



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REPORT ON TILE PO rIND GAP REGION.



marks the starting-point as a receding crest. Hence this fault-
ridge has been described as of much more recent origin than
the Cumberland antidlinal.
   But the great contrast in these receding escarpments should
not alone determine the comparative lateness of the formation
of the fault-ridge. The synclinal slopes of these mountains
show about an equal progress of the wearing agencies. The
general inclination of the rock-beds being about the same in
both mountains (15 to 25 degrees), or, if there is any difference
in dip favoring erosion, it is with the Cumberland slope. This
fact should greatly qualify the inference drawn from this strik-
ing contrast in the two receding crests. The truth lies between
these conflicting records. And whichever indication may be
regarded as most important, the harmonizing of the two must
be regarded as emphasizing very greatly the effects of varying
exposure to the sun. The face of Cumberland mountain and
the slope of the Pine are fully exposed to the direct rays of the
sun, while the slope of the Cumberland and the face of Pine
mountain present northward exposures. It is, doubtless, very
largely owing to this that the very great inequality in the
retreat of the two crests is set over against the equal erosion of
the synclinal slopes. The erosion of the receding wall of the
Cumberland and of the Pine mountain slope has been greatly
accelerated by more frequent and more effective alternations of
sunshine and frost. The same effect is prominent in the valleys
along the fault line of the latter mountain. These valleys are
to the northward instead of to the southward of the fault line,
as should have been expected from the well-known acceleration
of erosion with increased dips, other conditions being equal.
   It still remains that the Pine mountain fault is considerably
later in time than the Cumberland uplift. It is undoubtedly a
sequence to the general movement attending the formation of
the latter mountain.
         TIIE IRON ORE OF PINE MOUNTAIN.
   As indicated by the accompanying profile section, two regu-
lar iron ore horizons are brought above the drainage by the
   Prof. N. S. Shaler. Vol. 1Il, New Series, p. 224; also report on the region ad-
jacent to the Kentucky and Virginia State-line, by P. N. Moore, Part 4, Vol. IV,
New Series.



ii

 

REPORT ON THE POUNqD GAP REGION.



Pine mountain uplift; the same that are exposed by the cutting
away of the overlying rocks along the front of the Cumberland
mountain. The Limestone ore of the profile section is the
same as the Red River ore, which falls below the drainage in
the western border counties of this coal-field. (See report on
the Red River Iron district, report on the Iron ores of Green-
up, etc., also report on the Geology of Menifee, Vol. C., reports
on the Eastern coal-field.) Not much is known of the thickness
and persistency of this ore in the Pound Gap region, as it is
usually covered by the soil and mingled fragments of rock,
which cover the face of the mountain to a considerable depth.
It is seen at many points in a weathered state upon the surface,
sometimes, as at the heads of Pigeon-roost Br. and of Toms Br.
of Elkhorn creek, in a spur of Pine mountain it is exposed
in great profusion over the surface.
   The quality of the ore is not inferior to that of Estill and
Menifee counties. Whether it is thick enough for profitable
mining, dipping as it does into the face of the hill, is a ques-
tion to be settled by practical tests. The surface indications are
favorable, but could not be held as conclusive except as to the
equivalency and the uniform good quality of the ore.
   The Upper Silurian, or Dyestone ore, may, with reasonable
certainty, be assumed to occupy its regular place in the beds at
the foot of the mountain, as indicated by the profile section.
In this region it is everywhere covered by the abutting coal-
measure rocks or by the talus from the ledges of overlying
rocks. The tendency of the valley to wear away from the face
of the mountain leaves a foot wall of horizontal Carboniferous
rocks the whole length of the ridge, except at the water-gaps.
And, contrary to the occurrence in the Cumberland mountain,
the water-gaps are at points of least upthrow, so that the ore is
not exposed the whole length of the mountain except at Elk
Gap, (Safford.)
   Along the face of the Cumberland mountain none of these
conditions stand in the way of a study of the ore, which occurs
in several beds, or interferes with the ready mining at many
points far north and south. The time may not be far distant,



i2

 


REPORT ON THE POUND GAP REGION.



'however, when it may be desirable, even at greater expense, to
develop this ore in connection with the coking coals, which are
being developed west of the Cumberland mountain.
   On Elkhorn creek another ore occurs which does not belong
to the Pine mountain series; but as it is a local deposit along
the face of the mountain, it may properly be described in this
connection.  This bed has the character of a recent deposit,
though its occurrence at many points along the valley on both
sides of the creek at the same horizon, apparently, and the sim-
ilarity of the arrangement of the parts of the bed at widely
separated exposures, make it appear like a continuous bed. It
is made up of from one to three feet of anhydrous sesqui-oxide
of iron, including many fragments of sand-rock and siliceous
shale, the latter, apparently, greatly changed by heat. The ore
Is also in part blistered and porous, as though through the
agency of heat. Resting on this there is generally found from
one to two feet of earthy ore, or red ocher, with small fragments
of siliceous rock intermingled. In general, the lower part in-
cludes too great a proportion of siliceous material in the form of
fragments ef sand-rock to be valuable. In places, as noted near
Levi Potter's, it will probably be found comparatively free from
these objectionable features. An analysis made at the Labra-
tory of the Survey of a sample from this place shows the fol-
lowing results:
    Moisture.................................................6............................ 1.060
    Iron per-oxide.............................................................. 59.630
    Alumina ......................... 7.927
    Phosphoric acid ...........     .563
    Phosphorus..............................2................3................. .  .234
    Siliceous residuum......... ........................................... 29.73
    Metalic iron..............                        41.74
    It is probable that this ore is a rim deposit, but nothing has
been noted which explains its occurrence at this particular
horizon; and the appearance of metamorphosis cannot be readi-
ly explained from the data at hand. No indications of heat in
connection with the Pine mountain fault have been observed at
any place. But if this ore is a rim deposit, it is, doubtless, of
later origin than the fault-ridge, and as it extends laterally

   For description of the Upper Silurian iron ores see report of P. N. Moore on
the Iron Ores near Cumberland Gap, Vol. C., Reports on the Eastern Coal-field; aW
Vol. IV,INewSeries.



13

 

REPORT ON THE POUND GAP REGION



across the valley in association with the undisturbed coal-bear-
ing strata, there is apparently no good reason for supposing
that this ore has at any time been subjected to a high degree of
heat, unless a burning coal-bed be assumed to have been the
source. Locally coal-beds in this region are found to be burned
out for a considerable distance under ground, but no indications
of a coal-bed have been seen at this level. The most that can be
said for this ore is, that it is probable that it may prove valuable
as an iron ore locally, and generally as a source of red ocher. It
is exposed along the Elkhorn valley, from near the mouth of
Sycamore Creek towards the head for six miles or more. On
Pigeon-roost Branch it is 285 feet above the main creek. On
Harvey Gibson's land, opposite side of the valley, about the
same level. It is relatively lower up the creek, being 150 feet
above the main drainage at Levi Potter's.

                       COAL BEDS.

   The coal-bearing rocks of this region are, as a whole, con-
tinuous with those of the lower counties. The series is greatly
thickened, and includes an increased number of coal beds, but,
as already indicated, presenting a section so different as to make
the recognition of coal beds as continuous with those in the
sections of the lower counties difficult, if not impossible. The
progressive changes in the general character of the rocks in
Lawrence and Johnson counties, as mentioned in the report on
that region, are suggestive in this connection, but only a study
in detail of the thickening series, from the outcrop to Pine
mountain, can give a full solution of the question of equivalency
of beds in the Eastern coal-fields.
   There are some features that have been traced across the
whole field which serve to indicate in a general way the rela-
tions of the parts of the vertical section in the different portions
of the field. The shales above the conglomerate, fifty feet thick
in the western part of Greenup, and 150 feet in Lawrence, are
readily recognized on Elkhorn and Shelby creeks, in Pike coun-
ty, with a thickness of 450 feet. Elsewhere in the Pound Gap
region only a part or none of this portion of the section is above
the drainage.



14

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P/ate D.

 


REPORT ON THE POUND GAP REGION.



   The first persistent coal of importance above the conglomer-
ate formation is towards the top of these slhales, in the latter as
well as in the former region. The occurrence of calcareous con-
cretions, which become abundant in Lawrence county, associated
with coals 1 and 2, is even more noticeable in the Pound Gap
region along with the coals of the same general level, here in-
creased in number to four beds or more. These concretions are
prominent in many localities, and at levels ranging through 300
feet of vertical section. (See Sections 7, 8, 13, 18 and 27.)
They appear generally as lenticular earthy calcareous segrega-
tions, varying in size from a few inches to fifteen feet in greatest
diameter. In some instances they are fossiliferous, and in many
instances they show a well-defined concentric structure. Less
frequently these calcareous deposits appear as more or less
regularly jointed layers, or as continuous beds. Plate C shows
some of these lenticular bodies as imbedded in the slaty shale
at the top of the shale series on Carr's Fork of the Kentucky
river, at Kelly's mill, in Knott county.
   The section above is not so easily comparable with what may
be supposed to be the corresponding part of the general section
in the counties near the border of the coal field. There are
some points of resemblance; and some features have been traced
with some degree of certainty, across the intervening territory.
But the requirements of this report will doubtless be satisfied
without urging the matter of equivalency beyond these general
statements.
  There appears to be no workable beds of coal either below or
in the conglomerate series of this region. There are no expo-
sures to show the thickness of the sub-conglomerate shales.
From the surface indications along the face of Pine mountain
it is probable that less than fifty feet of the general section is
occupied by these beds, which along the border of the coal field
are relatively much more prominent, and at some points, as in
Menifee county, include a workable coal. (Vol. IV., Part II.,
and Vol. C.) The conglomerate formation has a maximum thick-
ness of 2,000 feet, made up of coarse ferruginous and more or
less conglomeratic sandstone, alternating with shales in such a
way as to form five or six benches where the whole series is
exposed. Cros8-bedding is a noticeable feature throughout the



15

 

REPORT ON THlE POUND GAP REGION.



formation. Quartz pebbles varying from the smallest to one-
half or three-fourths of an inch in diameter, are somewhat irreg-
ularly prominent, forming what in that region is spoken of as
hailstone grit; a rock from which millstones of good grinding
quality are made. Thin beds of coal have been noted at points
widely separated, as at the Breaks of Sandy, in the lower benches
as exposed along the river; and on the Pine mountain, south of
Whitesburg. Professor Stevenson finds six thin beds at Pen-
nington's Gap, in this group (Geological Reconoissance of parts
of Lee,Wise, etc.,Va.); and it is not unlikely that something
like the same number would be found in this region if all the
shales could be examined. On the re-appearance of this forma-
tion to the southwest in the region of the south fork of the
Cuiberland river, several inter-conglomerate coals are workable
beds. (See forth-coming report on the coals of Pulaski and
Whitley counties.)
   The first coal bed of more than local importance, beginning
at the base of the series above the conglome