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Field Columbian Museum

Publication 53.

Geological Series. Vol. I, No. 8.

)

OBSERVATIONS ON INDIANA

CAVES.

BY

Oliver Cummings Farrington, Ph.D.,
Curator, Department of Geology.

Chicago, U. S. A.
February, 1901.

TABLE OF CONTENTS.

Page
Observations on Indiana Caves, - - - - - 247

Wyandotte Cave, ... ... 247

Marengo Cave, .... ... 256

Shiloh Cave, - - - - - 262

Coan's Cave, - - - - ... . . 26\

OBSERVATIONS ON INDIANA CAVES.

A visit of the writer to several caves in Indiana during the
months of August and September, 1900, afforded an opportunity for
a number of observations which seem to be new or confirmatory of
observations previously published by others. The caves visited
were Wyandotte Cave, Crawford County; Marengo Cave, Crawford
County; Shiloh Cave, Lawrence County; and Coan's Cave, Monroe
County, all in the State of Indiana. Detailed descriptions of all
these caves have been given in several reports of the Geological Sur-
vey of Indiana, the latest and most complete being in the twenty-first
annual report, 189b, by W. S. Blatchley. There is also given in that
report a bibliography of the caves and their fauna.

WYANDOTTE CAVE.

Circular or Dome-shaped Halls. — The hall known as " Helen's
Dome" has to a marked degree the form of a hollow cylinder standing
vertically. " Rothrock's Cathedral " has the form of a huge dome
roofing a short cylinder, the center of the dome being in turn cut by
a cylinder rising above it. The "Senate Chamber" has a similar
form except that its shape is elliptical rather than circular. "Odd
Fellows' Hall," " Milroy's Temple," the "Hall of Representatives,"
and others are likewise dome-shaped. The hall known as " The
Rotunda" in Mammoth Cave has also the form of a dome roofing a
short cylinder. The dimensions of some of the halls as given by
Blatchley* are as follows: Helen's Dome, 80 feet high and 20 feet
in diameter; Rothrock's Cathedral, 185 feet high and 200 feet in
diameter; the Senate Chamber, bo feet high with elliptical axes 144 feet
and 5b feet in length. The circular or elliptical contour of the walls
of these halls and the persistence with which it is maintained through-
out successive downfalls of rock is remarkable and indicates that
some cause additional to ordinary water erosion must be sought.

*Op. cit.

247

248 Field Columbian Museum — Geology, Vol. i.

Water flowing down vertical joint planes usually produces pits with
walls of angular contour, of which the "Bottomless Pit" in Mam-
moth Cave may serve as a type. It is possible that the circular
contours may arise from a solvent action added in an unusual
degree to the erosive action of water. By this means the solid
angles of the limestone blocks formed by the junction of several ver-
tical with one horizontal joint plane might be dissolved away until a
dome-shaped cavity was formed, or the form may be due to a
concretionary structure of the limestone like that recently noted in
Idaho.* The consecutive removal of the centers of successive domes
would cause each to fall in turn, maintaining the dome-like shape.
Stream erosion on the floor of such halls may remove this rocky
debris as fast as it falls as has been the case at Helen's Dome, or the
rise of the conical pile of rocky debris (such as that known as
"Monument Mountain" in Rothrock's Cathedral), may nearly keep
pace with the fall of the domes above. It is evident that if this
process of caving in is continued until the surface is reached,
"cistern-like pits leading down into the bowels of the earth" will
be seen from above. Such is the description given by W. H.Holmest
of the cenotes or sacred wells seen in Yucatan, some of which are so
round and even-walled as to be taken for works of art. They are
often, Holmes states, 100 feet or more in depth and 200 or 300 feet
in diameter. It seems evident from what has been stated above that
human agencies need not be appealed to for the formation of such wells.

Fissure Systems. — Systems of fissures forming rectangles or
parallelograms closely resembling those produced byDaubr£e's well-
known experiment illustrating the formation of joints by torsion are
to be seen at many places along the roof of the cave. As an exhibi-
tion of jointed structure on a horizontal plane they are very satis-
factory. Often a secondary system of fissures appears in conjunction*
with the primary one. In many places, such as the "Pillared Pal-
ace," the formation of stalactites and stalagmites has taken place
along the lines of the joint planes. The stalactites and stalagmites
extend, therefore, in straight lines in most cases directly beneath the
crevice made by the joint plane.

Distribution of Bats. — Bats were found in all parts of the cave
which I entered, even in the so-called "Unexplored Regions," the
entrance to which is a passage averaging about one foot in height for
a distance of 60 feet. If the bats were especially numerous any-
where, it was in the hall known as the "Senate Chamber," which,

*A curious mineral formation in Idaho Engineering and Mining Journal, March 2, 1901.
tField Columbian Museum Publication 8, p. 19.

Feb. 1901. Observations on Indiana Caves — Farrington. 249

according to Blatchley's measurements, is one and one-sixth miles
from the entrance to the cave. I may also remark that I noticed a
similar wideness of distribution of the bats in Coan's Cave, though
that is only one-eighth of a mile in length. These observations
seem to contradict the statement of Mr. William H. Hess,* that "bats
as a rule go but a short distance from the entrance," and throw
doubt on any theory of the origin of' nitrates in cave earths which
rests on the assumption that bats do not inhabit the mora remote
portions of caves.

Vermiform Stalactites. — The vermiform stalactites which are to
be seen in many places in this cave have attracted the attention of
many observers and brought forth many theories as to their origin.
These theories are admirably summed up and the subject ably
treated in the paper by Merrill " On the formation of stalactites and
gypsum incrustations in caves, "f My observations lead me substan-
tially to agree with Merrill's conclusion that the, vermiform character
of stalactites of this cave is due to the fact that the drops of water
making them have been guided to other positions than those dictated
by gravity by the directions assumed by spicules of calcite in crystal-
lizing. It appears to me, however, that the carbonate of lime pro-
ducing this effect must be in a condition differing somewhat from the
ordinary pulverulent form in which it appears at the end of the
usual stalactite tube, or in other words, that some additional condi-
tions must be appealed to in order to lead to the formation of stalac-
tites of this sort.

The resemblance of the stalactites to the well-known forms of
aragonite denominated flos ferri is quite striking, and perhaps of some
significance. Senft^ reached the conclusion that the flos ferri forms
of aragonite were produced from very dilute solutions of carbonate of
lime, which, owing to protection from changes of air and tempera-
ture, evaporated very slowly. Calling attention to the form of
the spicules of aragonite he deduced much the same theory for* the
origin of the flos ferri forms as that suggested by Merrill for the
Wyandotte Cave vermiform stalactites. It is characteristic of ara-
gonite, however, to crystallize in slender needles, but not so of cal-
cite. Tests which I have made of the specific gravity of the sub-
stance of the Wyandotte vermiform stalactites indicates that it is, as

♦Journal of Geology, Vol. 8, No. 2.

tProc. U. S. Nat. Mus., Vol. XVII, pp. 77-81.

JDie Wanderungen und Wandelungen des kohlensaures Kalkes, Zeitschrift der Deutsche
Geologische Gesellachaft, Vol. XIII, p. 269.

250

Field Columbian Museum — Geology, Vol. i.

originally regarded by Merrill, calcite. The exact stages of the proc-
ess by which vermiform stalactites of calcite would be produced
seem to me, therefore, less evident than are those by which such
stalactites of aragonite are formed. Yet, until we have better knowl-
edge it may be a reasonable hypothesis to suppose that the same

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Fig. i— Deposits produced by capillary attraction, on a stalactite, a glass rod and a glass tube.

conditions which produce such forms in aragonite (supposing Senft
to have correctly judged those conditions) viz.: deposition from
dilute solutions in sheltered situations, may be regarded as those
which would produce similar forms of calcite. Why, however, ara-
gonite should be produced in one case and calcite in the other, I can-

Feb. 1901. Observations on Indiana Caves — Farrington. 25r

not say, while further it may be noted that Foote's* experiments led
him to conclude that rapidity of crystallization causes the formation
of aragonite rather than the slow crystallization which Senft has
postulated.

Deposits Produced by Capillary Attraction. — The force of capil-
lary attraction cited by Merrill as producing the vermiform stalac-
tites is probably instrumental in modifying the forms of stalactites in
general in a way to which attention does not seem to have been
called before. In fact, it is probable that deposition from this cause
takes place on a much larger scale than has hitherto been supposed.
The nature of such deposits can be instructively determined experi-
mentally. As deposition of carbonate of lime from solutions would
take place too slowly for convenient study, I have used solutions of
salt for this purpose.

Fig. 1 shows a deposit of salt formed
by capillary attraction on a slender
stalactite, a glass rod and a glass tube
respectively. These deposits were ob-
tained by supporting the several objects
on end in a solution of salt to a depth of
about one-fourth of an inch (6 mm.) for
a week. The deposit on the stalactite,
it will be noted, gathered about numer-
ous centers giving a stippled appear-
ance like that often seen on stalactites
and illustrated by the figure of the stalac-
tite shown in Fig. 2. This is in accord-
ance with the well-known tendency of
crystals to form secondary and tertiary
branches. It is to be noted so far as the
deposit on the glass tube is concerned
that none formed inside the tube.
Hence the stopping up of stalactite
tubes cannot be ascribed to this cause.
Attention may also be called to the large
amount of deposit both on the tube and
the rod, as indicating how considera-
ble a deposit on stalactites may result
from capillary attraction. In Nature it
is to be supposed that the capillary
currents producing such deposition

Fig. 2— Stalactite.

Marengo Cave.
showine form probably influenced
by capillary deposit.
% nat. size. (Mus. No. G. 963.)

♦Abstract in Am. Jour. Sci., Vol. 160. p. 392.

252

Field Columbian Museum — Geology, Vol. i.

would take their origin from the larger current trickling down
the side of the stalactite and from the drop of water at the
end. That currents rise from the drop of water at the end of a stalac-
tite may be proved by the clumsy and not-recommended-often-to-be-
tried experiment of holding a lighted candle for a moment close
under the drop. The particles of soot thus left in the water will be
seen to whirl about for a long time, much longer than any convection
currents produced by the heat of the candle would account for.
This motion continued in one stalactite which I watched for a period
of five minutes, and it, may be, is still kept up. The deposit formed
under the conditions of the above experiment with salt may be con-
sidered illustrative of one produced by rapid evaporation from a con-
centrated solution. The subject evidently admits of much further
treatment experimentally by way of determining what variations, if
any, would be produced in the nature and amount of the deposit by
employing solutions of different strengths, by varying if possible the
rate of evaporation and by the use of different salts.

The " Pillar of the Constitution." — Fig. 3. The shape and
size of this huge stalagmite have often been described. It is located
in the hall known as the " Senate Chamber," which is accurately

Fig 3— The "Pillar of the Constitution," Wyandotte Cave.

Feb. 1901. Observations on Indiana Caves — Farrington. 253

described by Collett* as " a vast elliptical amphitheatre * * *
The sides are built up with massive ledges of limestone, thinning
and converging upward into a monster dome with a flat elliptical
crown 50x20 feet in diameter. The center of this vast room is piled
up with a great mass of rocky debris fallen from the immense cavity
above." Blatchleyt gives the exact measurements of the hall, so far
as its length and breadth are concerned, as 144 feet and 56 feet
respectively. He gives further the following graphic description of
the Pillar: '* The mass of fallen rock in the center, known as 'Capi-
tol Hill,' is about 32 feet in height, and is crowned to a depth of
several feet with an immense mass of stalagmitic material. From
the center of this mass rises from the top of the hill the grandest
natural wonder in Wyandotte Cave — the great fluted column of satin
spar or crystalline carbonate of lime known as the ' Pillar of the
Constitution.' Perfectly cylindrical, 71 feet in circumference, and
extending from the crest of the hill to the ceiling above, this enorm-
ous column exceeds in magnitude any similar formation in any known
cave on earth." No statement of the height of the Pillar is given by
this author. Collett states that the Pillar is about 35 feet high, and
Mr. H. A. Rothrock, the present manager of the cave, informs me
that this is undoubtedly correct, so far as the southern side of the
Pillar is concerned. Owing to the fact that the stalagmite is situated
a little to one side of the apex of the cone of debris, the deposit has
formed about ten feet farther down on the southern side than on the
northern. On the northern side, therefore, the height is about 25
feet. The mean of these, or 30 feet, may be taken as the height
above the debris as a wb^ole. The intimate structure of the mass as
shown by examining fragments taken from the pit artificially exca-
vated at its base is distinctly banded or onyx-like. The individual
bands are so narrow as to be scarcely distinguishable with the naked
eye, but these are grouped into series of larger bands, 0.5 mm. to
5 mm. in thickness, which differ in color or in structure so as to be
plainly distinguished from one another. A secondary fibrous struc-
ture in which the fibres are at right angles to the plane of deposition
has been developed through most of the bands. The latter lie for
the most .part nearly horizontal, but occasionally are highly contorted.
The only statement I can find as to the mineralogical nature of the
substance of the Pillar is that of Blatchley, who refers to it as made
up of "satin spar, the purest form of carbonate of lime." Having
examined somewhat carefully the substance of several hand speci-

*Indiana Geol. Survey, 1878, p. 473.
tO/. cit., p. 156.

254 Field Columbian Museum — Geology, Vol. i.

mens which I took from the Pillar I find them to be made up chiefly
of aragonite. Not only is the specific gravity that of aragonite (2.92)
as obtained by Thoulet's solution, but several cavities show the typi-
cal radiating bladed crystals of this form of carbonate of lime. The
occurrence, therefore, furnishes an exception to the rule noted by
Merrill* that the onyx marbles are generally calcite. Between the
distinctly fibrous layers of some portions are interposed other layers
microgranular and non-fibrous in structure. The substance of these
I found to be of lower specific gravity than that of the fibrous layers.
It is in other words, calcite. Here, then, are variations from arago-
nite to calcite taking place in the growth of a single mass represent-
ing corresponding variations in the circumstances of its growth. A
similar occurrence is noted by Senftf in a deposit near Eisenach,
Germany. It is unfortunate that our present knowledge of the con-
ditions bringing about the formation of these two salts is so inade-
quate that we cannot know exactly what changes are indicated by
such alternations.

Age of the Pillar. — The immensity of this stalagmite, and the
certainty that it has been formed by a fairly uniform process of
deposition, lead almost irresistibly to an inquiry as to whether any
satisfactory estimate of the length of time required for the forma-
tion of the mass can be made. Some attempts seem to have
been made to determine the rate of deposition by measuring the
thickness of the film formed upon glass vessels left in the water
now dripping at the Pillar. Unfortunately these measurements
are not very accurate. Collett states on ^ne page of his report
(p. 467) that water dripping "at the ' Pillar of the Constitution ' has
deposited a film of less than one-fiftieth of an inch during five years,
or at the rate of one inch in 250 years," while on another page (p.
474) he states that " an estimate based on quasi observations places
the rate of this stalagmitic growth at one inch in 100 to 150 years."
Hovey, in his "Celebrated American Caverns" (p. 138), speaks of
the Pillar as growing ten inches in 1,000 years, though he gives no
data on which to base the statement. Mr. Rothrock, the present
proprietor of the cave, has at my request had a new vessel placed
in the water since my visit and it is hoped that this may fur-
nish a means of accurate measurement in a few years. For the
present, however, taking Collett's lower rate of one inch in 250 years

*The Onyx Marbles: their origin, composition, etc., Rep. U. S. Nat. Mus., 1893, p. 553.
tO/. cit., p. 289.

Feb. 1901. Observations on Indiana Caves — Farrington. 255

as probably the nearest correct, it can be easily calculated that 90,000
years would have been required for the Pillar to rise to its present
height had the flow of water during all this time been uniform over
the constantly increasing surface. I believe it safe to regard this as
a minimum age for the Pillar, though I am well aware that owing to
various factors which may give rise to fluctuations of growth, geolo-
gists are accustomed to believe that no satisfactory time values can
be assigned to measurements of stalagmitic deposits. See Dana's
Manual of Geology, 4th edition, p. 1024. But may not these fluctu-
ations be confined within limits as narrow as those affecting other
measurements of time, such as the rate of recession of gorges or the
rate of sedimentation, especially when we remember that variations
in the rate of deposit almost certainly find expression in the form of
the stalagmite? The stalagmite under discussion certainly has a
remarkably symmetrical form. I believe, therefore, that it must have
grown at a fairly uniform rate.

Regarding the possibilities of arriving at any satisfactory value
of the mean age of the Pillar, I have no very lively hope of suc-
cess. It is hardly likely that the flow of calcareous waters over
the entire mass of the Pillar was constant throughout the period of
its growth. At the present time, growth is hardly taking place over
one one-hundredth part of the surface, yet a mean value can be
assigned to this factor only in a purely arbitrary way with nothing to
guide the judgment that I can think of. The data for assigning an
age value to the large stalagmite now in the Museum of Science and
Art, Edinburgh, seem to me better founded. This stalagmite is n
feet long and 28 inches in diameter. It was sawed from its base in a
cave in Bermuda in 1819. In 1863, Sir Alexander Milne in visiting
the cave measured the amount of matter formed on the base since the
removal of the stalagmite and found it to be five cubic inches. At that
rate it can be easily calculated that about 600,000 years were
required for the formation of the stalagmite.* Numerous considera-
tions show that it would be incorrect to apply this ratio to the forma-
tion of. the 20,000,000 cubic inches of matter which make up the
Pillar of the Constitution, and I introduce the illustration only to
show that a much greater age should probably be assigned the
Pillar than that which I have given as a minimum. In addition
to the time consumed in the growth of the Pillar, a large previous
period was required for the erosion of the chamber in which it stands.

•My data are from the Museum label. I think the facts have been published, but I cannot
give the reference.

256 Field Columbian Museum — Geology, Vol. 1.

Data are meagre for estimating the length of this period. Prestwich*
has estimated the rate of erosion by the Thames as one inch in 1,000
years. The chalky Cretaceous and Oolitic strata over which the
Thames flows are doubtless eroded at a more rapid rate than the com-
pact limestone in which Wyandotte cave is situated. Taking this
rate, however, as a minimum, it will be found that a period of 360,000
years would be required to erode the "Senate Chamber" to the
depth of the base of the stalagmite.

MARENGO CAVE.

The Cave Floor Terrace. — The greater portion of the floor
of this main cave shows a well marked terrace recording two distinct
stages in the life of the stream which before its final disappearance
flowed through the cave. Of these two stages the stream of the
older stage had a width of from 15 to 20 feet and a current of
sufficient velocity to make large ripple marks on its bed of coarse
alluvium. These ripple marks are symmetrical and their long
slope is plainly away from the present entrance to the cave. This,
therefore, was the direction of flow of the stream. In its second
stage the stream was reduced to a width of about 10 feet and its cur-
rent was more sluggish. It cut a trench of the above width with
nearly vertical walls to a depth of about two feet in the bed of the old
stream, but did not have a current of sufficient velocity to produce
ripple marks on its bed. A further greater sluggishness as compared
with the first stream is indicated by the somewhat winding course
which it took through the bed of the latter. The disappearance of
this stream must have taken place somewhat suddenly, for there has
been no trenching of its bed nor sloping of its banks such as would
have occurred if the flow of water had diminished gradually. The
bed, now quite dry, has a slightly concave form. A draining away of
the stream by the opening of new conduits at a lower level seems the
most natural explanation of its two stages and final disappearance.
It is of course not impossible that these stages mark a diminution in
rainfall or supply of waters from above, but there is on the whole
little reason to suspect such abrupt changes in these conditions. It
is not unlikely that the large spring situated a few rods west of the
present entrance represents the present point of issue of the stream.

*Geology, vol. i, p. 107.

Feb. 1901. Observations on Indiana Caves — Farrington. 257

Stream Deposit. — Gradual diminution in rate of flow is well
shown in the deposit left by a stream tributary to the main stream to
be seen at the point called the "Sand Pit" between the " Rock of
Gibraltar" and "Fortress Monroe." The stream had a course
nearly at right angles to that flowing through the main cave, although
its course, as its channel is filled nearly to the roof, can not be fol-
lowed backward except by digging. Where this tributary emptied
into the main stream it formed a delta deposit about eight feet in
depth. The main stream in cutting downward has cut through this
delta so as to expose a complete section. The deposit is well strati-
fied. There are slight variations in the coarseness of adjacent strata
throughout the deposit, but the most striking feature is the obvious
gradation from coarse pebbles at the bottom to fine alluvium at the
top. The pebbles at the bottom are well rounded sandstone pebbles
having about the size of English walnuts. Only a stream of con-
siderable swiftness and volume could have transported them. From
such a velocity of current the stream diminished until it bore only the
finest alluvium in its latest stages. What could have led to such a
diminution in its rate of flow is not apparent, but it is evident that
waters flowing through limestone are liable at any time and to any
extent to be drawn off in new directions by the opening of new con-
duits.

Abundance of Stalagmites. — A remarkable feature of the por-
tions of the cave known as "Cave Hill Cemetery" and the "Prison
Cell" is the relative abundance of stalagmites. Many of the stalag-
mites have no corresponding stalactites at all. There can be little
doubt that the principles enunciated by Senft* provide adequate ex-
planation of the origin of such results. Senft showed that when
the flow of water through a crevice was too rapid, either on account
of the verticality of the crevice or the abundance of the water supply,
to allow of evaporation and consequent deposition sufficient to form
a stalactite, a stalagmite might yet be built up because of the greater
opportunity for evaporation given for water falling upon the cave
floor. He supported this conclusion by calling attention to the fact
that stalagmitic icicles form during the hours of the day when melting
is most speedy. These suggestions seem to furnish sufficient
explanation for the facts referred to.

Origin of Peculiar Forms of Stalagmites. — The form of many of
the stalagmites is remarkable and, so far as' I know, peculiar to this

Op. cit., p. 287.

•V

258 Field Columbian Museum — Geology, Vol. i.

cave. The form to which I refer is that of which the stalagmite
known as "Washington's Monument" (Fig. 4) may serve as a type.
It may be described as one which would be produced by piling a

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Fig. 4 — "Washington's Monument," Marengo Cave.

number of irregular, successively smaller, truncated, inverted cones
one above the other. At first'sight this structure appears very regu-
lar and suggests rhythmic variations in the supply of matter in the
formation of the stalagmite. On close examination, however, it will
be seen that the widenings and narrowings are not horizontal, nor do
they extend uniformly around. They are rather of the nature of
irregular projections and indentations. Such being the case, it
seems to me that slight movements of the point of dropping of the
water which formed the stalagmite would be sufficient cause for its
form. Such variations in direction of growth of a stalagmite are
illustrated in a section of one from Robertson's Cave, Springfield,
Missouri, shown in Fig. 1, PI. XXXII. Up to a point about one-third
of the way to the top, growth was in a direction to the right. Then
it turned to the left and then became more nearly vertical. Such
variations might especially be expected where no stalactite existed
above to maintain the point of dropping in one place, as is the case

LIBRARY
UNIVERSITY OP ILLINOIS

I » D R

Explanation of Pl. XXXII.

Fig. i. Section of stalagmite from
Robertson Cave, Missouri,
showing changes in direc-
tion of growth.
(Mus. No. G 604.)

Fig. 2. Cone-shaped stalagmite,
Marengo Cave.
(Mus. No. G 1022,)

Feb. igoi. Observations on Indiana Caves— Farrington. 259

with those under discussion. If it be considered further that varia-
tions in the form of a stalagmite may result from variations in the
rate of evaporation and content of carbonate of lime of the water
which produces it, further reasons for the peculiarity of form will be
added. Thus, if evaporation is rapid, or the content of carbonate of
lime high, so that a large quantity of the salt contained in each drop
is deposited at the top of the stalagmite and little is left to be
relinquished in the subsequent course of the water down the sides, a
long, slender stalagmite will be formed. If, on the other hand,
evaporation is slow, or the content of carbonate of lime low, so that
deposition will take place about equally during the course of the
water over the stalagmite, a broadly conical stalagmite will result.
It is evident that such variations occurring during the growth of any
single stalagmite would find expression in corresponding forms in
different parts of the stalagmite.

Another form of stalagmite so far as I know peculiar to this cave
is that of a flattened cone. Such are the stalagmites known as " Mt.
Vesuvius" and the "Diamond Dome." The form is illustrated by
Fig. 2, PI. XXXII, showing a stalagmite collected by the writer at the
cave. I have indicated above in what manner slight evaporation as
compared with the rate of flow of water or a relatively low content of
carbonate of lime might be expected to produce such a form. It may
be further noted that the lateral surface of these stalagmites, instead
of being smooth like that of the ordinary stalagmite, is built out in a
series of sinuous walls running more or less horizontally around the
cone. These walls form numbers of little pools usually filled with
water and containing delicate crystalline aggregations of carbonate of
lime. The low slope of the surface allowing slow movement of the
water over it is doubtless responsible for the construction of these
walls.

Stalagmo-Stalactite8. — Usually in the growth of cave formations,
a stalactite forms above its counter stalagmite. An odd reversal of
this condition of things so that the stalagmite forms above the stalac-
tite is to be seen in several instances in this cave, the formation
known as the " Mermaid " being perhaps the best example. Such
stalagmo-stalactites are formed by a drip taking place on the edge of
a limestone shelf so that the water which builds up the stalagmite, in
pursuing its further downward course forms a stalactite as well. Of
the general appearance of such formations Fig. 5, showing a speci-
men collected in Shiloh Cave, will give a sufficient idea.

26o

Field Columbian Museum — Geology, Vol. i.

Molecular Arrangement of Stalactites and Stalagmites.— The
substance composing the stalactites and stalagmites of this cave is
generally made up structurally of fibres radiating outward from the

center. The fibres pass unin-
terruptedly through the concen-
tric rings of growth and the
structure is doubtless, therefore,
as pointed out by Merrill,* of
secondary origin. The fibrous
substance is not, however,
aragonite, but calcite. In con-
trast to the forms possessing
this structure are many whose
substance has a wholly coarsely-
crystalline structure exhibiting
an all-pervading rhombohedral
cleavage. Intermediate stages
between these two extremes can
be seen in many cases. Of
especial interest are stalagmites
exhibiting a structure like that
shown in Fig. 6. This figure
shows a cross section of a
stalagmite, the peripheral por-
tions of which are fibrous in
structure while the central are

Fig. 5— Stalagmo-Stalactite, Shiloh Cave. , , . , , T r ,

(Mus. No. G. 884.) rhombohedral. I am of the

opinion, though I know of no way either of proving or disproving
it, that such a structure is evidence of a progressive change in the
molecular arrangement of the substance toward a more stable con-
dition. It is certain that it is in the older portion of the stalagmite
that the molecules, are arranged along the rhombohedral planes, and
I have never found the positions reversed. That the rhombohedral
condition is more stable than the fibrous seems to be indicated by
the fact that the former is characteristic of the oldest and most meta-
morphosed calcite-bearing rocks. Prof. D. G. Elliot has suggested
to me that pressure on the internal substance of the stalagmite may
also be largely instrumental in bringing about the;$feange to a rhom-
bohedral condition. This is not unlikely. But whatever the deter-
mining causes, the case seems to furnish an instructive illustration of

*Op. cit.,x>. 78.

Feb. igoi. Observations on Indiana Caves — Farrington. 261

progressive molecular arrangement. The carbonate of lime was
deposited first in narrow, concentric bands. The substance then
rearranged itself in the form of more or less continuous fibres
arranged at right angles to the planes of deposition. Then with the
lapse of time and pressure a second rearrangement was made by
which the attractive forces brought the molecules together grouped
along rhombohedral planes.

Fig. 6 — Broken end of stalagmite, showing change from fibrous to rhombohedral structure.

Rate of Growth of Stagmalites. — I propose this word, com-
pounded from drdy/ua (drop) and MOos (stone), as a general name for
formations produced by dropping water.

Under the present usage the expression stalactites and stalag-
mites, each term of which has a limited meaning, is the only one
available. So many stagmalites in this cave are in process of forma-
tion that it seems a favorable place for a study of their rate of growth
and of the variations which occur in this rate. In the hope of obtain-

262 Field Columbian Museum — Geology, Vol. i.

ing, in the lapse of years, some data on this point Mr. S. M. Stewart,
manager of the cave, kindly allowed, at my request, several stalac-
tites and one stalagmite to be marked by Mr. Claude Stroud, who
lives near the cave, and who, by keeping watch of their growth, can
note any variations which they undergo. It will be understood, how-
ever, that the rate of growth is so slow that it is not likely that before
the end of ten years at least any appreciable change will have taken
place. The record of the stalactites marked is as follows:

No. 1 Near " Tower of Babel," Drops at intervals of 3V2 minutes.
No. 2 In "Queen's Palace," " " " " 45 seconds.

No. 3 " " " il 216 times per minute.

These are simple stalactite tubes.

The stalagmite marked is in "Crystal Palace Gallery," and
receives eighteen drops a minute.

SH1LOH CAVE.

Eroded Stalactites. — The stalactite shown in Fig. 7, occurring
near the southern end of the cave, furnishes an interesting illustra-
tion of the fact that cave waters may vary in their action from forma-
tive to erosive, according to the quantity of carbonate of lime they
contain. Thus, in the case of the stalactite here represented, the
waters flowing over the limestone shelf to which it is attached had at
one time built it up to the general form shown. Later, however,
the character of the waters changed and they began to erode, as shown
by the pits on the surface, the very mass they had previously built
up. These processes of deposition and erosion are, of course, going
on side by side in nearly all limestone caves, but it is not often that
erosion follows so rapidly after deposition. Many smaller stalactites
in other parts of the cave show similar erosion.

Leaf Stalactites. — Many of the stalactites of this cave are leaf-
like in their form so far as this may describe a broad, thin and
pointed shape. Often the appearance is that of a series of ovate
leaves folded along their midribs and hanging down from a project-
ing ledge. The "leaves" of one such projecting mass are nearly
six feet in length, and the weight of the mass must be several thou-
sand pounds. It is remarkable that such a weight can be sustained

Feb. 1901. Observations on Indiana Caves — Farrington. 263

Fig.

as it is at right angles to
the wall. Observation
of the broken end of
any of the "leaves" of
such a group of stalac-
tites will show the man-
ner of growth. (See
Fig. 8.) Such growths
are not formed by water
trickling down a crevice,
but from currents de-
bouching over a lime-
stone sheff. The shelf
must project slightly
and the current of water
must be relatively large.
There are first formed
stalactites of the ordi-
nary conical type. Then
deposition is confined
only to one side of the
stalactite, the side,
namely, over which the
descending water flows.
Growth takes place then
almost wholly in this
A deposit is, however, also

-Eroded Stalactite. Shiloh Cave.
(Mus. No. G.881).

direction and in the direction of length
built up from the surface of the shelf by the water flowing over it.
So the mass grows upward in a thin layer, downward at the
stalactite points and outward in thin sheets at right angles to the
cave wall. There is also a slight lateral growth of the stalactites
which causes them in time to join one another, and the group thus
acquires the appearance of a continuous sheet thrown into folds.
The original stalactite points usually continue to be the points of
greatest growth in length, but the stalactite may be longest some
distance away from these. Corrugations of the surface showing
retardations of the flowing waters, and similar to those so common
on icicles, are nearly always present. If the current is compara-
tively narrow and maintains its position for a long period of time the
stalactitic mass will take a semi-circular form owing to the fact that
the portions in the center of the current receive more material than

264

Field Columbian Museum — Geology, Vol. i.

those at the side. The mass in Shiloh Cave mentioned above and
the "Canopy"* in Wyandotte Cave, are excellent illustrations of
such formations.

COAN'S CAVE.

The spelling, "Coon's", given by Blatchiey| for the name of this
cave seems to be incorrect. According to residents of the region the
cave derives its name from one of the original owners of the land on
which the cave is situated, whose name was Coan.

The entrance to the cave is well-shaped, and is not unlike the

« m;

Fig. 8— Diagram illustrating manner and directions of growth of leaf stalactites. The arrow shows
the direction of the water current. The cross section at the left shows rings of growth.

descriptions given of cenotes previously referred to. The cavity
gradually enlarges toward the bottom. A small surface stream occa-
sionally flows into the cave. The entrance is a good illustration of
ingress obtained by following the path of the stream which has
formed the cave, in contrast to the entrance to Wyandotte and Mam-
moth Caves, which are of the nature of openings made by a fallen
roof.

♦Figured in Report of Indiana Geological Survey for 1896, PI. X.
tO/. cil., p. 129.

LIBRARY
UNIVERSITY OF ILLINOIS

URSANA

FIELD COLUMBIAN MUSEUM.

GEOLOGY, PL.XXXIII.

Explanation of Pl XXXIII.

Strings of crystals obtained from solutions of copper sulphate, lead chlnrkh
and nickel-alum, showing increase in size of crystals and amount of deposit
toward the bottom of the solutions. A shot used to weight the string appears in
the central figure.

Feb. 1901. Observations on Indiana Caves — Farrington. 265

m

m

The most unique feature of this cave is the pool at its end,
excellently described by Blatchley.*

The calcite crystals which line the walls of the pool are made up
of the unit rhombohedron r (1011) and the unit prism of the first
order m (1010). (Fig. 9.) The crystals have all grown in a direction
at right angles to the plane of their attachment. The prism is quite
short, and no crystals are doubly terminated. The crystals vary in
size from quite minute to those the size of an ordinary acorn. It is
noticeable that they increase in size toward the bottom of the pool.

In order to determine whether it was
commonly true that crystals increased
in size toward the bottom of a solution,
with the assistance of Mr. H. W.
Nichols, I prepared solutions of a
number of salts, placed them in long
slender jars and then immersing strings
vertically, noted the quantity and size of
crystals deposited. In nearly every
case the deposit took a marked conical
form. The base of the cone and there-
fore the greatest amount of deposit was
at the lowest point in the solution. It
was also generally true that the size of
the crystals increased toward the bottom. The accompanying plate
(PI. XXXIII), showing strings of crystals obtained from solutions of
copper sulphate, lead chloride and nickel-alum, illustrates this. Such
results point to a greater concentration of solutions at the bottom,
a principle already established with regard to solutions in general by
Ludwig and Soret.f It may be worth while, however, to call atten-
tion to this illustration of the principle, and to the fact that the
size of crystals depends on the degree of concentration of the solution
no less than on the time given for their formation.

In this part of the cave stalactites and stalagmites of the ordi-
nary type appear in close association with the crystal deposits just
described. The formations have a similar origin in that they are
both deposits of carbonate of lime from solution in water. They
differ only in the condition that in the making of stalactites and stal-
agmites the water was moving, while in the making of crystals it was
still. If I am correct in this conclusion the converse of the principle

Fk;. 9— Calcite, Coan's Cave.

*Op. cit.. p. 132.

tBecker, Am. Jour. Sci., Vol. 153, pp. 21-40.

266 Field Columbian Museum — Geology, Vol. i.

affords a rule perhaps of some value as a guide to the conditions
under which banded formations have taken place as compared with
those which exhibit distinct crystals. Substances deposited from
solution in water which exhibit a banded or layered structure have,
according to this rule, been formed by moving waters, while those in
the form of distinct crystals have been deposited from waters at rest.
Hence, the banded structure so characteristic of mineral veins may
be considered proof that the deposit was formed from moving waters
while the occasional cavities lined with crystals show points at which
the solutions were at rest. Similar conclusions may be drawn
regarding the same structures as seen in agates and geodes. It is
evident, further, that the conditions in the two cases also differ
in the quantity of liquid present and in the rate of deposition. The
layered structure is the result of trickling waters from which deposi-
tion is necessarily rapid, while the distinct crystals were formed from
a solution which was present in quantity, and from which deposition
was comparatively slow. The applications of these principles to
conclusions regarding the origin of veins are obvious. The terms
motion and rest are, of course, here to be understood in a purely
relative sense, as no body of liquid would be entirely free from
internal currents. Further, it is to be granted that all gradations
may be traced between a banded structure and distinct crystals. In
a broad sense, however, the rule stated in these terms may be of
some value.