IflLLS. W.tf.

Physiographi ; and Ecolos^ic^l
Study of the Lake Winona
Region, Ind .

CHIC

IK QUA*

A Physiographic and Ecological

Study of the Lake Eagle
(Lake Winona) Region, Indiana

By
W. MAGOON MILLS, S. B.

Th« UnlvertUy of Chicago

CHICAGO
THE QUADRANGLE PRESS

1902

PREFATORY NOTE

The following report is the result of a summer's work
done in connection with the Biological Station of the Indiana
University at Lake Winona, Ind. The locality is a hydro-
graphic basin representing a physiographic and ecological
unit, and for that reason is one well adapted for a study. Dur-
ing the first part of the summer, the class in ecology under
Dr. H. C. Cowles, of the University of Chicago, had for their
work the tracing of the natural history of the locality along
ecological lines, and also to show what was going on at that
time in the same line. It was while this work was in progress
that evidences were discovered in the physiographic history
which seemed to the writer extremely interesting. Accord-
ingly, the physiography was incorporated with the ecology in
the report.

Return is here made for the co-operation of the other
members of the class: Miss Belle Highlands, of Madison, Ind.,
Miss Lucy Youse, of Terre Haute, Ind., and Mr. Collett, of
Zenia, Ohio. To his instructor, Dr. Cowles, the author feels
deeply indebted, not only for aid in the present effort, but for
kindly guidance and suggestions which have characterized
their class associations for the past few years. No one has
done more to impart courage to the novice or to lift the be-
ginner toward professional work than he.

Chicago, III., November 75, 1901.

1. Topographic Map of Lake Eagle Region.

A PHYSIOGRAPHIC AND ECOLOGICAL

STUDY OF THE LAKE EAGLE (Lake

Winona) REGION, INDIANA

Eagle Lake or Winona Lake, which, together with the ad-
jacent area is the subject of this paper, is located immediately
southeast of the junction of the P. Ft. W. & C. Ry. and the C.
C. C. & St. L. Ry., in the northern part of Kosciusco Co. Ind.
At present it consists of one main body of water about one
square mile in area although formerly it was much more ex-
tensive. The area drained into the lake or"catchment basin"' is
unusually large when compared with the lake body. The trib-
utary streams are two; Cherry Creek from the southeast and
Clear Creek from the south. The amount of inflow from these
two streams is quite insignificant when compared with that
supplied by the numerous springs about the lake. These
springs with one or two exceptions, are more or less regularly
distributed along the eastern shore of the lake. The outlet is a
small stream leaving the lake at the southern end of the north-
west embayment and finds its way, after a sluggishly mean-
dering through heavy growths of semi-aquatic vegetation, to
the Tippecanoe River, about a mile west of Warsaw.

Recently a canal has been dug connecting the lake in a
more direct way with the Tippecanoe, by which a more effect-
ive drainage is furnished. By this means it is intended to
drain off the lake water from all the low lying lands so that
they maybe utilized for agricultural purposes. The shores of
the lake, in general, are ,low and marshy, beaches being few
and chiefly on the southern and eastern sides. Elsewhere, the
shores are over run by luxuriant growths of aquatic and semi-
aquatic vegetation. The bulrush, thriving in extensive beds
of peat and marl, is found in the shallow waters qf the lake
far from the shore. Thick beds of Chara occupy the shallow
waters in other parts which, together with the heavy beds of
water lillies (Nymphaea) and pond lillies (Nuphar) are rapid-
ly reclaiming the lake bottom.

Back from the lake there are elevations of some magni-
tude and fairly continuous. These are especially developed
upon the eastern side, where they frequently rise to heights
exceeding forty (40) feet. It is from this region that the lake
derives the major part of its water. The lake itself is not
deep and yet its depth when compared to that of inland lakes
in general, is somewhat striking. Less than a mile in width
for most of its length, it has an extreme depth of eighty-one
(81) feet. This lake is typical of the glacial lakes of northern
Indiana, all of them having bottoms rather deeper than the
elevations of their immediate neighborhood. While the area
here is not the "kettle and knob" topography perfect, such
as exists at Valparaiso, yet it closely approaches that, the ele-
vations and depressions being formed by the same agencies and
largely under the same circumstances. As compared with
these lakes, both those in the western states and those formed
by glacial agencies in Wisconsin and Michigan are extremely
shallow. The majority of the Nevada and Utah lakes, though
of great area, average but a few feet in depth.

THE TOPOGRAPHY

Lake Eagle owes its origin to glacial influences. When
the ice advance known as the Erie lobe moved southward and
westward, ft came in contact laterally with that ice advance
from the north known as the Saginaw lobe. The median mor-
aine, made up of long well marked ridges, is the region under
discussion and about to be described. The general direction
of this moraine is south 35 degrees west. All the glacial phe-
nomena, once so powerful in forming the surface here, may
still be approximately traced by their influences. The region
is covered with a very thick mantle of drift, not only the thick-
est in the state, but much thicker than has been found in the
states to the north. At Kendallville, Ind., a few miles to the
north, but yet on the summit of the same moraine, the drift
measures 485 feet in thickness. From this point south the
thickness varies, being 245 feet at Eagle Lake, while at
Wabash, 25 miles further south, it thins out to practically
nothing. At this point the underlying rock comes to the sur-
face. This moraine, in which Eagle Lake is located is one of
the six eliptically-shaped moraines which at present round the

FIG. i. A view across the lake from near the outlet. Evidences of
the rapid recession of the lake waters are plentiful. Most of the long tongues
of rising land are largely beds of Chara and other water plants, Zones
of white and yellow water lillies, cattails and sedges are seen near the
water while further to the right aones of willow, Carolina rose and osier dog-
wood merge with the more mesophytic of the forest trees. On to the right is
the regulation upland forest. Here is an example of swamp evolution.

FIG. 2. Swamp meadow recovered naturally from the lake and on its
southern edge. The forest in the upland back is an oak-hickory
one. White oaks occupy the lower part of the slope, the black oaks the
higher parts. If left alone, the meadow would become forested. The outer
rim of trees are of the mesophytic order, their seedlings being annually
destroyed by the mower. Ash. walnut, and swamp miple predominate
near the meadow,

2. Glacial map showing moraines in which Lake Eagle and the city of
Warsaw are located (Loaned by Prof. C. R. Dryer and Inland Pub. Co.},

western end of Lake Erie, and which formerly at successive
periods served to retain the waters of ancient Lake Erie or
Lake Whittlessey on the south, and which for a time emptied
its waters through the Ft. Wayne gap into the Wabash River.
The drift of the region is the regulation glacial till, such as
has been observed and studied throughout the glaciated por-
tions of the northern states. The soil content is largely made
up of sand and gravel with a small percentage of clay mater-
ial. The amount of clay or of the residues or any of the feld-
spars here, is extremely small when compared with that por-
tion of the till of the states further north. In Wisconsin for
example, and Illinois, the clay is often the chief constituent of
the soil, but wherever found near the lake under discussion, it
is of a light and soluble nature.

The surface is in general undulating, with here and there
an abrupt knob and kettle area. These knobs are dom^ shaped
and the sides are frequently as steep as the material will lie.

The basin or kettle is the exact opposite of the knob,
being formed into a deep rounded depression originally by the
melting of large masses of ice in the "till." These kettles are
trom various causes filled with water and many of them become
permanent lakes. Most of the lakes of northern Indiana owe
their origin to these depressions in the morainic ridges,

There are several hill like elevations, probably eskers,
scattered about the region standing usually at right angles to
the strike of the drift. A particularly large one known as
Chicago Hill, stands near the Biological Station at Winona.
It is to all indications, a typical esker. It is composed of sand
and gravel heterogeneously mixed. Its shape is high and oval
but not lenticular and in these characteristics it is neither a
kame nor a drumlin. This esker as well as all of the elevations
of the region, has a vegetative covering varying in density
according to conditions. As a rule, the slope to the south and
southwest, owing to the exposure to the more direct heat in
summer and consequent drouth, bears a type of vegetation
approaching what is known among botanists as "Xerophytic."
On the northern side of those hills however, owing to the in-
creased shade and consequent addition of moisture, there is a
transition from the xerophytic vegetation to that type
known as "Mesophytic." As these and other ecological terms

7

will be used more or less in this paper, it will be advisable to
briefly explain their significance. In 1895 Warming1, a Euro-
pean botanist, adopted these terms in his "Plant Geography."
He divided the plants of the world into four great groups:
Hydrophytes, or the plants which grow in water or wet places;
Xerophytes, the plants which grow in dry habitats; Mesop-
hytes, the plants which grow in places of. medium moisture;
such as ordinary forests and meadows; and Halophytes, or
plants which grow in salt water or alkaline soil. Most botan-
ists have accepted Warming's classification of plant societies
as a more or less complete organization of this part of the
physiographic-ecological field. The type of vegetation called
mesophytic, requires protection from the cold and heat in ex-
cess, as well as good moisture conditions. The black and
white oaks with an occasional hickory usually form the forest
covering on the southern and western slopes. As one passes
over the crest of these hills, however, a transition in the vege-
tative types is easily discernible. Descending the north-
ern slope towards the bottom of Cherry Creek near the Biolo-
gical Station, one first marks the elms. Following the elm
comes the aspen. Then the sycamore comes in still lower.
As one descends lower, the ash prevails. When the hill slope
merges with the flood-plain, the walnut and red-bud are more
predominant. Along the- creek's margin, always depending
upon the nature of the slope, the hazel, linden or basswood,
and the willow (salix nigra) occupy the space. The poplars
occur here too, but irregularly. These trees furnish the obser-
ver with a direct clue to tne topography It is now well known
that each particular topographic form has its own peculiar
vegetation. To make direct use of the words of one of the
foremost students and authors on the subject, "The reason
that the type of vegetation is so closely related to the type of
topography is that the soil conditions upon which the plants
depend are determined by the surface geology and geography.
From the standpoint of vegetation the topographic relations
are more important than the geological. The topographic
conditions determine the exposure, the presence or absence of
drainage, and the humus content of the soil, and are thus of
overshadowing importance. Having related the vegetation
largely to the topography, we must recognize that topography

changes, not in a haphazard manner, but according to well
defined laws. In all the processes of erosion there is no more
potent factor than that of vegetation. Regarding that many
things may be cited. The peat deposits add greatly to the
rapidity with which lakes and swamps are filled, while the
plant covering of the hills on the contrary, greatly retards the
erosive processes. As a consequence of all these topographic
changes the soils and slopes must change; so that the plant
societies which are replaced in turn by others, are adapted to the
new conditions.1' It will be at once seen that there are mutually
powerful agencies at work in an area like this of pronounced
topography and strong- vegetative influences. The erosive
influences are all but balanced by the constructive work of veg-
etation. Among the various types of elevations, the esker,
then represents a unit both topographically and ecologically.
It possesses on its surface trees and undergrowth ranging from
xerophytes to mesophytes. Within 150 paces, crossing its
crest transversely, one passes from the scrubby black oaks,
representing the xerophytic side, to groups of lindens and wal-
nuts representing the mesophytic side. With its elevation
of sand and gravel the esker furnishes the necessary condi-
tions of exposure and protection from the rigors of heat and"
cold and moisture, which determine the vegetative types of
its surface. What is here true of the esker is true of other
elevations provided that they are of the same soil. A clay hill
will differ in its vegetation from one of sand or gravel. How-
ever, the topographic relations are more important than the
geological, and hence one will observe that the change in.
vegetation is only a modification.

The vegetative influence on the entire topography is very
marked. Located in the belt of heavy rainfall, with an abun-
dance of water in the ground from spring's, and in the air from
evaporation of the lake's surface, the entire ground surface,
with the exception of certain elevations, is covered with a
rich herbaceous vegetation and the hills with dense forests.
Wherever interfered with the forests are not luxuriant but
where primeval they are grand in their thickness and deep
shade. One stretch of elevation on the 20 foot contour line,
and back from the lake shore a half mile, proved a magnificent
sight. The trees, nearly all mesophytes, were lordly monsters.

9

of the primeval time, towering high above without a linob or
shoot. Their bases were deeply covered with mosses and lich-
ens indicating the extremely favorable conditions for vegeta-
tion. Their roots were spread over a great area and owing to
the wet condition of the ground, they were arched into "knees."
The shade of this forest was so dense that only such plants as
ferns could prosper. There were many varieties of these and
their long and beautiful fronds grew in heavy clusters. A wagon
road had been opened up through one part and here the Im-
patiens, nettle, and the Pilea had made haste to get rooted in
the rich humus. On the edges of this road the hazel and the
red bud had become established. This was a beach-maple for-
est and these facts illustrate how completely shaded a meso-
phytic forest's soil is and also how largely all chances of de-
veloping undergrowih is shut out from it.

There is no doubt but that a generation ago there existed
here the densest and heaviest of woods. Old settlers say that
•even 50-years ago they were able to take out logs and timbers
which for size and value rivaled the best of the Michigan for-
ests. The natural undergrowth is so heavy in the open that
all lines of drainage are clogged and continually threatened
with destruction. In some cases these lines have been arti-
ficially reopened but only to again suffer destruction by vege-
tative obliteration. Lilies, rushes, cat-tails, and zone upon
zone of brush and shrub close in on the lake and continually
narrow its confines from the sides and raise its bottom by
heaps of debris of the dead plants. One would naturally ex-
pect that at the outlet of the lake there would be some or even
considerable erosion at the present time but there is none that
is perceptible. It is a case of a stream that has found its val-
ley, not made it. The outlet stream meanders along slowly
through dense masses of aquatic and semi-aquatic vegetation,
on a slope of exceedingly small gradient, until a point far be-
low the upper dam is reached. Here, the erosion setting in
from the Tippecanoe is asserting itself and the gradient in-
creases very rapidly. It seems that the ordinary course of
nature viz; cutting down by erosion and destruction of water
bodies by the ascending heads of tributary streams, is here re-
versed, and that instead, we have forces acting in the opposite
manner. This lake, as far as its water body is concerned,

10

would probably remain for thousands of years, vegetation pre-
serving it from any tendency toward destruction by drainage
and until the ascending line from the Tippecanoe would reach
the lake's margin. This point is now located between A and
and B on map I. At this point! erosion is active.

The lake itself presents a rare place for the aquatic plants
to perfect their types. The perfection of types, however, and
the enormous multiplicity of numbers means, sooner or later,
death to the lake itself. The shores low and marshy, also pre-
sent the most favorable surroundings for the furtherence of
vegetative growth. Great beds of Scirpus skirt .these shores
and extend far into the lake. Thick beds of Chara and pond weed
^ Potamogeton) are closer in shore. In intervening places on the
marshy shores extensive beds of the pond-lilly (Nuphar) with
their heavy, soggy stalks and enormous spread of leaves are aid-
ing the other types in raising the lake's bottom with the de-
bris of the dead and dying plants. Back ot the immediate
margin of the lake but still in very wet soil, are beds of cat-
tail growing luxuriantly and beyond these the heavy swamp
grasses are established. Then the vegetation increases in
height and size and thick zones of brush intervene between
the lake and the first line of trees. Among the more plenti-
ful varieties of the trees associated with the lake and its life
history, is the willow and particularly, the Salix nigra. Wher-
ever one may go about the lake's vicinity, these black willows
are always in evidence. From the fact that most of them are
now in full maturity, their existence there seems to point to a
time when conditions differed essentially from the present.
Many of them are dying which also points to a changing en-
vironment. They stand for the most part in continuous
lines or zones and suggest the pre-existence of water lines.
They are in their youth, associated with running or quiet
water so that now one can say, since they are in full maturity
and far from any water, .that they once marked the edge of
the lake. This inference comes from observation of the
the habit of the tree and its love for water, for when
the spring comes and the young shoots appear, along the
water's edge a long line of willow shoots are seen bevond
where any other plant has ventured. The seeds ot other
plants have gone as far perhaps, but could not endure the

conditions and the place has fallen to the willow. Hence it is^
now generally recognized that a line of willows in natural sur-
roundings, indicates a former water line even though there is-
no beach-line in evidence.

Extending through the mesophytic forests on the low
ground about the lake and especially upon the southern and
eastern sides, are numerous lines, in some cases double.
These lines are those made by willow trees. Between these
lines of trees there is an intervening space of about twenty-five
feet. The lines are made up of fully matured Salix nigra. These
lines are so peculiarly continuous that they seem to-
indicate the former margin of drainage channels. These lines
representing tributaries, have in the last century, occupied)
many different channels. The streams have wandered at will
over old lake bottoms, whence the lake water has receded, so-
that'they represent typical flood-plains. It is on these prim-
itive flood-plains that Salix nigra grows in such continuous
lines, suggesting the history, at least in part, of the creek and
lake. In one small area especially studied, six different oscil-
lations of the channel were observed. In some cases the evi-
dence of ecology was corroborated by the still lingering de-
pressions or extinct channels in the ground.

THE ANCIENT LAKE

About one-fourth mile to the east of Chicago and Hamil-
ton Hills, the two eskers mentioned near the Biological stat-
ion, one comes suddenly upon aMarge and continuous embay -
ment. It is now dry having no water connection with the
lake. Formerly it was filled with an arm of the old lake.
Now it has the appearance of a deep and wide valley. Hid-
den from view by heavy forest growth, the valley appears as a
case of past erosion at a time when an enormous amount ot
water went through it. It is impossible to suppose that the
present feeble stream which meanders through the deepest
parts was ever competent to perform any such amount of ero-
sive work. It seems like placing the Tippecanoe River in the
valley of the Mississippi and making it responsible for the
valley. The idea, then, that this great embayment was the
result of erosion, is clearly unsatisfactory. Neither is it prob-
able that the valley is one formed by river erosion but one evi-

12

3. Map of "The Embay meet" and the Cherry Creek Valley.

FIG. i. A view looking lengthwise E. & W. of the "embayment"
discussed in the text. In the extreme right winds the main branch of
Cherry Creek while on the left may be seen the higher points of the la-
custrine beach. The vegetation, both of the trees and the undergrowth, is
very characteristic of such a slope. The trees vary from the black and
white oaks on the left to poplars, sycamores, and elms in the centre and
the black willow (salix nigra) on the right. In the left foreground are the
bogs mentioned, in which the biological remains are so well preserved.

FIG. 4. View at the point of greatest gradient and erosion in the
head waters of the Tippecanoe where the stream has all but succeeded in
tapping Eagle Lake. The lake is less than a half mile distant. The view
also looks diagonally across the site of the greater dam to the southern
abutment. This is 22 feet high, at the base of the large white oak in the
back. The stones in tha foreground are nos'.ly limestones of the till.

dently formed by three forces. First, the shape of the topo-
graphy as left by the glacial ice; second, the erosion which
has gone on both with the creek's aid and by side wash; third,
the effect of lacustrine action and forces which have been long
at work and have accomplished much as will be evident later.

In observing the contour map it will be seen that this en-
bayment formerly stood at the lake's edge, but the lake has
since evidently receded. As one ascends the depression to
the eastward, (this depression is 500 feet wide, and more than
2,000 feet long to its southward turn), he will observe upon
the left hand a broad sloping beach extending eastward to the
turn mentioned. Its base begins in a line eight feet above the
present lake level, and gently and evenly ascends to a height
of eighteen feet above the lake. It is decidedly lacustrine in
shape and formation and can in no way be laid to river terrace
work. Across the valley southward no beach exists, the
peculiarity of the formation being1 that the beach is found only
on the northern side. This beach occupies a space between A
and B on map 3. It will be seen that this beach, supposing
that the lake levels stood as indicated on the contour map,
marks the place that would be subject to the strongest wind
and wave action. The prevailing winds of this locality being
those of the same latitude, viz; southwest, and there being an
expanse of water surface some two miles long, it will be seen
how easily this beach might be developed. Remove the pres-
ent intervening mesophytic forest existing between this point
and the lake's margin; raise the lake level over 20 feet, and
one can readily imagine what the situation might be and what
the opportunities for the development of such a beach were,
The ecological factor in proving up the beach is close at hand.
»

,A line of Salix nigra of full maturity skirts the lower edge
of the beach clearly indicating the former reach of water and
of willows, about eight in number, is plain and sharp in out-
lines, representing a gentle concave curve toward the present
channel. At the bases of these trees there is a somewhat
sharp declivity of about three feet indicating that while the
level of the water stood here, the outlet, for some reason, was
suddenly lowered. For the reason that the exact age of these

13

willow trees was not ascertained at the time of the writer's
visit here, and no safe comparison can be now ventured be-
tween the ages ot these and other old trees lower and nearer the
lake, it is perhaps better to offer this last evidence with this
note. It seems that the line of Salix nigra spoken of indi-
cates the former margin of the lake shore. Whether this is
from the fact that water was formerly here and this is what ap-
pears to be so, or whether the trees in their growth took ad"
vantage of the shape and slope of the declivityls not positive.
Tt is better to use the evidence as corroborative perhaps, to
take the evidence of the line of willows with that of the exis-
tence ot the beach and the deposits of the bivalve shells.
The strongest evidence on the point would not be the ecologi-
cal, nor the geological but the zoological. When once
the two latter have been accepted, it is easy to see
the place and force of the ecological evidence.
Back of this beach formation, the surface rises rapidly
and abruptly twenty-four feet above the lake level. Beyond
this higher altitudes obtain until heights of fifty and sixty feet
are marked by the aneroid.

On a level with the beach and on the northern side of
nearly the whole length of the embayment, which is between
7500 and loooo feet long, are numerous springs and peat bogs.
These springs' and bogs are perhaps among the most remark-
able things to be noted in the locality, for from their peculiar
nature emanate many other phenomena such as the preserva-
tion of old lacustrine biological remains and the cementation
by their calcareous waters of the glacial sand and pebbles of the
bog's vicinity into a conglomeratic mass. This is ot course
a post-glacial conglomerate. The spring waters, nearly al-
ways associated with the bogs, issue from the ground cold and
heavily charged with calcareous salts in solution, which, upon
the evaporation of the water, succeeded in cementing the peb-
bles and sand particles, among which the water was filtered,
into the conglomerate. These masses of cemented rock are
found quite plentifully here on the g"ul!y slopes and in
great hill side masses at Wabash. For illustration of this see
Fig 8. These spring waters on entering the lake, have their
temperature effectually raised so that any body with which

14

they happen to come in contact becomes entrusted with
limy scales. The plants of the lake in particular, are acted
upon in this manner and are materially increased in weight and
bulk, thereby augmenting the vegetative and mineral deposits
upon the lake bottom.

Upon a level with this beach and on the northern side ot
this embayment are located many deposits of shells and vege-
table remains. These deposits are in the bogs before men-
tioned. The nature of the soil of the bog is such that it will
preserve from oxidation and destruction any fossil remains
either of vegetative or animal nature and especially important
for the point at hand, calcareous shells. These shells are those
of lacustrine life, hence in these bogs may be found well preser-
ved relics of past years which aid in the interpretation of the
natural history of the region. Apart from these bogs the
soil has not aided in protecting these plant and animal re-
mains from total destruction either by oxidation or by the
root acids in the soil. It is practically a waste of time to
search through sandy soil or through soil much exposed to the
forces of weathering for remains such as are spoken of for the
reason that they will be entirely consumed in oxidation. In
these bogs are large deposits of univalve and bivalve shells.
The univalves, although plentiful, do not necessarily give evi-
dence of lake life for it is well known that they frequent both
the waters of lakes and springs. The existence of the uni-
valves in the bogs alone and separate from any other evidence,
furnishes only valueless and unconvincing proof for the bogs
are or have been associated with the springs.but the occurrence
ot tne bivalve shells with them renders the conclusion more
certain. The bivalves are, on the other hand, never found
apart from lake-life and therefore never in springs, so that the
existence of the lake level formerly at this point is demonstra-
ted. It is proven in three ways. First, geologically, by the
detailed account of the probable formation of the beach men-
tioned; second, botanically, by the zones of Salix nigra willows
lining the beach after their habit and lifehistory is recognized;
third, zoologically, by the numerous deposits of shell life in
the bogs now existing on a level with the beach and in the
close proximity thereto. This one case of verifying scientific

u

theories in the field certainty convinces one of the extreme
value ot associating the sciences together especially where
they are so closely related as Physiography and Ecology.
When a small knowledge of one is once gained it is next to
impossible to rely alone upon the other. Dr H. C. Cowles of
the University of Chicago, made a visit with the writer to the
localities mentioned and it was apparent that the formations
and deposits were due entirely to lacustrine action and that
the further evidence necessary to establish the fact that the
ancient lake stood at these altitudes and was instrumental in
the creation of the evidence cited, was, after demonstrating
the existence of a 10 and 20 foot contour line around the lake,
to locate if possible, a dam or the remnant of one at the out-
let.

• The contour lines of 10 20, and 30 feet are not altogether
continuous in the vicinity of the lake especially on the nor-
thern shore. While the surface rises to higher altitudes east
of the lake, on the south and west the surface is so effectually
broken up by embayments that it is with difficulty that the
contour can be traced. Those east and south ot the lake are,
however, fairly continuous. The 10 foot line is followed with
but little difficulty but the 20 foot line takes in such a vastly
greater area that it is necessary to make constant reference to
the level and aneroid to establish it. There is no doubt that
the 3o foot line would include not only most of the city of
Warsaw, but even Centre aud Pike lakes. On the west the
high grounds close in rapidly upon the lake and since
this side is free from tributaries, there are practically no em-
bayments. Of course at the outlet there is a depression lead-
ing toward the Tippecanoe River. This depression as far
westward as the letter B on map I, was filled with water when
this lake was at its maximum height. Thisembayment varies
greatly in width and is about one and a half mile long. For
most of the distance the 10 foot contour line runs close to the
channel, the 20 foot line setting back considerably. All of the
contours converge at B which was found to be the location of
the greater dam. At A five eights of a mile east and where
the 10 foot lines are seen to converge, was found the location
of the lesser dam. These two dams contained the ancient lake
waters.

16

4. Map of the outlet of the lake with cross cuts of the two dams.

The lesser dam at A map t, if it now existed, would have
a crest twelve (12) feet above the lake waters, and would fill
in the valley here north and south. ' The three contour lines
converge perceptibly here on the west, but only the 10 foot isac-
tually at hand. The altitudes go above it however on the west-
ern side, reaching nearly eighteen feet. A heavy mesophytic
forest is growing all about the place both on the heights and
in the old valley, so that any continuous view is impossible.
On the eastern side there are two twelve foot hills which form
the eastern abutment. This dam was apparently the last one
to give way and its long continued influence in retarding- the
ancient waters is distinctly seen all about the lake's shores.
Indeed, in a way, the effect of this dam was more powerful
and enduring than that of the greater one, for while the work
of the higher waters was on a more magnificent scale, yet
much of their work has long been effaced, while that of the
lesser waters through the longer period of action, has been
more pronounced. A great deal of the finest bluff work of the
higher waters has been nearly obliterated by weathering,
while the work done by the lower waters has been largely pre-
served by the heavy growth of vegetation upon the lower bluffs
and embayments These lower evidences of lake action may
be easily recognized and traced by the willow zones before
mentioned.

The larger dam at B has abutments still standing indicat-
ing th&t when existing it had a crest of twenty-two feet. It
crossed the valley transversely and was much wider and more
massive in every way than the smaller dam. Both of these
dams were formed by glacial action, the material probably be-
ing heaped together laterally in ridges as indicated by the con-
vergence of the contour at this point. The great beach on the
eastern side of the lake was formed while this, the larger dam
was intact. After a length of time had elapsed, the length of
which it would be difficult to measure, the upper part of the dam
slowly yielded to the overflow, and as fast as it gave way the
faster the water flowed through the gap until the cutting
reached the bottom. The abutments receded until they reached
the steeper slopes of the side hills, where the force of the
corrasion was greatly diminished. By this time the bulk of

the water of the ancient lake had passed on its way and had
reached the Tippecanoe, a mile further to the west. It was
at this time and not until then, that the overflow began on the
small dam. The time necessary to destroy this one, although
much smaller and retaining a vastly smaller basin of water,
must have been very long, even vast, to permit the work
that was accomplished by the waves of that long period. When
we think of the almost even conflict that is now going on be-
tween erosive and constructive forces with the ever deepening
drainage lines on one hand and their continued tendency to
become obliterated by vegetation, on the other, and the many
years needed to show progress on either hand, some concep-
tion may be had of the lapse of time between the accumula-
tion of the lake body and the final outflow through the eroded
dam. Jt is interesting to think that the erosion lines seen
now ascending the outlet from the Tippecanoe (See figure 4 of
the report), would have crept up the gradient from the river,
and succeeded in tapping the lake at the greater dam whether
the crest had yielded to the force of the overflow wear or not.
However, it would yet take many years for this danger point
spoken of to reach the dam and begin its work. The soil of
these dams is of course the same existing in the other parts of
the morainic uplands of the locality, sand and small gravel
being1 the chief constituents. The measurements and other
items of the dams as well as two maps of the same, may be
seen in other parts of the report.

THE LAKE SHORES

The vegetation of the lake and that of its shores is materi-
ially effected by the nature of the soil of its bed and margin.
•The soil at any point is determined by forces and factors in
constant operation, chief among which is the proximity to ele-
vated lands. The erosive forces of this area are powerful,
both by reason of the rainfalls which are heavy and the nature
of the soil which is such as to be quickly affected by water.
The amount of detritus removed from the top and side of a
hill during the season of heavy rains is enormous, especially
when these points are denuded of forests and under-vegetative
growth. It is not uncommon to see deep gullies, running to

18

FIG. 5. Sample of Jasper conglomerate found plentifully on the sur-
face around the lake. The specimen is eight inches In diameter.

FIG. 6 Samples of the post-glicial conglomerate found near the
mineral springs in Cherry Creek embaymsnt and in large masses at
Wabash. The glacial pebbles are resting in a matrix of ordinary sand,
the whole cemented by the calcareous water of the springs. It is not easily
fractured. The above is now in the ge:>logical collection of the Field Mu-
seum where it is unique in being the only evidence of a calcareous conglom-
erate formed by calcareous springs.

the base of a hill, after a severe rainfall, their whole course
lined with deep potholes formed by the rush of water and the
whirl of the till boulders. The load of detritus spread in a
huge alluvial fan at its base, will in many cases measure twenty
cubic yards. When the hill slopes to the lake shore, this
eroded material, it will be seen, determines the soil content of
the beach, especially where there is no intervention of bottom
or marsh. The small amount of clay in the till, owing to its
very light nature, is carried away in suspension.

It has been suggested that the stretches of sandy beach
of to-day might be accounted for by the combined forces of
wind and wave action, grinding up the glacial pebbles and
spreading out the accumulation to form the beach. The occur-
rence of some of these sand beaches on the north-eastern
shores, where the south-west winds for most of the year spend
their force, might seem to partially corroborate this, but surely
a second thought would dispel it. In the first place no glacial
pebbles (quartz pebbles) are exposed to the action of the
waves, the accumulation of peat and marl completely covering
so heavy and immovable thing as a pebble. The light shifting
sands consequent on the side-wash and erosion of the adjacent
hills keep the marl and peat deposits well under cover in their
immediateneighborhood. In the second case, long stretches of
sand beach occur on the southern and eastern shores, where
the prevailing winds do not cause the waves to beat. There
has been someconfusion in passing judgment on this point. A
'beach on this lake, and the other lakes of the neighborhood,
is either sand or marl, and it should be easy to determine
which. It should be easy to distinguish between a beach
made up of fragments and particles of shell-life which is
largely calcium carbonate and one made up of sand and gravel
mainly the oxide of silica. It is clear then, that the origin of
these sand beaches is connected with their closeness to the
sand and gravel hills and ridges, the change in place being
effected by erosion and side-wash, and not in grinding and pil-
ing up by wave and wind action of glacial pebbles.' A casual
inspection of the map of contours should show this.

The stretches ot marl beach are in part one of the present
enigmas to be cleared. They seem, on close inspection, to

19

consist of particles and fragments of shells from mussels down
to univalves. However, when the extreme depth of these
marl deposits and beaches, which ranges from two to twenty
feet, and the size of the lake together with its life capacity is
considered, there certainly seems to be a discrepancy in com-
parisons. Probably all of the deposit is not made up of min-
eral calcareous matter from the springs, or of animal calcare-
ous matter, but in addition to both of these there is a third
element, viz.; the remains of lake vegetation which formerly
was, while growing-, encrusted with a limy covering. Nothing
aside from close chemical examination would satisfactorily
determine the solution to the question, whether these exten-
sive deposits depend upon the mineral deposits of the springs
upon the remains of shells, or upon the lacustrine vegetation.
The deposits must have covered an area commensurate with
that of the ancient lake for at points some distance from the
present lake margin, marl deposits have been found with evi-
dence indicating that they were continuous with those of the
present lake. At several points about the lake, canals have
been dug, and in all instances deep beds of marl have been
unearthed. There is above this bed a thick solid layer of peat
about a foot and a half in thickness. It would be interesting
to compare a chemical analysis of this ancient marl, so old as
to have a dry solid bed of peat covering eighteen inches, with
one of the present time.

There is in the area here a dearth of the boulders gener-
ally seen in the till of glaciated countries. Those that are here
are small and do not at all compare with the great masses of
them either in Michigan or Wisconsin. Neither do they com-
pare in the variety seen in the fields mentioned. A part
of this dearth is due no doubt, to the greater distance from the
original location of the rock outcropping.many being dropped
by the way. Again the reduction in size was probably affect-
ed by the increased allotment of time in transit which means
of course, continuance of the grinding process by the ice.
The prevailing boulder is dolomite. Then comes the granite,
usually very numerous and large in glaciated countries but
here very small. Diabases are few and also quite small.
Some Jasper conglomerates are to be found scattered on the
till surface. One of these appears in one of the figures of the
report.

PAT. JW 21, 1908

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