Bulletin No. 273 Series B, Descriptive Geology, 76

DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

CHAKLES D. WALCOTT, DIRECTOR

THE

(PRELIMINARY PAPER)

BY

WILLIAM C. ALDE3ST

WASHINGTON

GOVERNMENT FEINTING OFFICE

1905 . '

CONTENTS.

Page.

Letter of transinittal. -..---'-.--.----..-.---.----...--.-.-......-........-- 7

Introduction. ........................'.......................-.....-..-.-.. 9

Distribution and orientation............................................... 9

Relations to terminal moraines .--...............-...... ........-..-..--.- .1.2

Relations to eskers.... - ..........................................^........ 15

Distribution of drumlins relative to pre-Glacial tomography and to general

configuration of drift surface............ ..'............................ 15

Distribution of drumlins relative to one another ........................... 17

Forms of drumlins....--.....".........--........--.............-....--.-... 18

Structure of drumlins ..................................................... 25

Stratified beds in drumlin sections .......................................^ 29

Brown loam and loess coatings ........................................... 82

Lithological composition of the drift........... ..-....-.--.-. ..-.....-..- 38

Distribution of local material in the drift................................. 36

Local quartzite drift in the drumlins ..................................... 37

Origin of the drumlins............... ..--....----.......-...------..----.. 38

Summary..................................._............................ .41

Index .........:i.......................................................... 45

3

ILLUSTRATIONS.

Page. 

PLATE I. Map showing Pleistocene deposits of a portion of southeastern

Wisconsin _______-___.__.._.____________._.. ..----_--_._-_-_-- 10

II. A,- Drumlin 2 miles west of Sullivan, Wis., viewed from the 

northeast; B, transverse profile of the drumlin shown above, 

viewed from the north.......................-...--.--... -.. 12

III. A, Drumlin about 2"miles north of Sullivan, Wis., viewed from 

the west; B, transverse profile of the drumlin shown above, 

viewed from the north_____..____..-.._.___..----.-.._-__-----. 16

IV. A, Transverse profile of a drumlin 5 miles southeast of Stoughton, 

Wis., viewed from the north; B, drumlin 2 miles northeast of 

McFarland, Wis., viewed from the west---------------------- 20

V. A, Transverse profile of a drumlin 2 miles northeast of McFarland, Wis., same as PI. IV, B, viewed from the northeast; B, 

longitudinal profile of a double-crested drumlin at McFarland, 

Wis., viewed from the east....----.-.-..-.......--.-........- 22

VI. A, Transverse profile of a double-crested drumlin at McFarland, 

Wis., same as PI. V, B, viewed from the south; B, transverse profile of a triple-crested drumlin at McFarland, Wis., 

viewed from the south.._...__...-_____.---,---....-.--._._.-.- 24

VII. A, Ledge of quartzite 4 miles northeast of Waterloo, Wis., viewed

from the west: B, same ledge viewed from the north.......... 28

VIII. A, Contorted beds of stratified clay and sand exposed in a road 

cut through a drumlin 14- miles east of Hebron, Wis.; B, cleavage developed in the clay matrix of till exposed in a road cut 

through a narrow drumlin 5 miles northeast of Waterloo, Wis. 30

I.. A, View showing in detail the distortion of stratified beds of clay

and sand exposed in a road cut i mile east of Johnson Creek,

Wis.; B, Stratified sand and clay, interbedded with till, exposed

. in a road cut through a drumlin 1 mile east of Johnson Creek,

Wis --.-._...._..----.- .-..._--.---.- --...-.---._-....---.. 32

FIG. 1. Sketch map showing relations of drumlins of the Q-reen Bay Glacier to terminal moraine deposits of the final retreat of the ice 

front .._--,.-----_-_.-----._-..------.---_..,.-.----.--. :....... 13

2. Sketch map showing relations of drumlins of the Green Bay Glacier

to tei-minal moraine deposits of the final retreat of the ice front.. 14

3. Sketch showing variations in forms and sizes of drumlins of the

Green Bay Glacier............................................. 20

4. Sketch showing variations in forms and sizes of drumlins of the

Green Bay Glacier .............................................. 21

5. Sketch showing double-tailed, double- and triple-crested drumlins,

anddramlin twins and triplets...-'...........-.'..-..-......-.-.- 23

6. Sketch showing the association of large and small drumlins and the 

development of overlapping crests on elongated dmmloidal 

ridges --..-.--... ..-..-.-.-...............-.....--.........-.-- 24

7. Section of drumlin 2£ miles northwest of Johnson Creek, Wis.... 30

8. Section of a drumlin 1 mile east of Johns n Creek, Wis............ 31

5

LETTER OF TRANSMITTAL.

DEPARTMENT OF THE INTERIOR, 

.UNITED STATES GEOLOGICAL SURVEY,

Washington, D. C., April 11,1905.

SIR: I transmit herewith the manuscript and illustrations of a 

report entitled " The Drumlins of Southeastern Wisconsin, (Preliminary Paper)" by Mr. W. C. Alden, and recommend it for publication 

as a bulletin.

The formation of drumlins has recently awakened renewed interest 

and discussion, and it seems very desirable that the data carefully 

gathered and organized in this paper should be placed before scientific investigators who are interested in this difficult subject. 

Very respectfully,

C. W. HAYES,

Geologist in Charge of Geology. 

Hon. CHARLES D. WALCOTT,

Director United States Geological Survey.

1

THE DRUMLINS OF SOUTHEASTERN WISCONSIN.

(PRELIMINARY PAPER.)

By WILLIAM C. ALDEN.

INTRODUCTION.

For several seasons past the writer has been engaged in a study of 

the Pleistocene and underlying formations of southeastern Wisconsin, 

under the direction of Prof. T. C. Chamberlin. Within the area 

covered by the survey, approximately 4,200 square miles, there are 

about 1,400 drumlins, of greater or less perfection of development. 

Most of these drumlins (1,269) belong to the ground moraine of the 

Green Bay Glacier, the southern 37 miles of Avhose length is here 

included; 74 lie in the area traversed by the Lake Michigan Glacier 

of the late Wisconsin invasion, and 62 form part of an older drift 

deposit lying outside of the bulky moraines of the late Wisconsin 

glaciers, which is thought to have been formed at either the low an 

or the Illinoian stage of glaciation. For purposes of study and conir 

parison with similar phenomena of other regions it has.been thought 

advisable at this time to correlate the mass of data already on hand 

concerning the drumlins of this region and present them in this form. 

No attempt is here made to reach final conclusions, as the study is 

yet in its early stages. It should be borne in mind that such deductions as are made are based solely on phenomena thus far observed, 

and, being tentative, are subject to modification as the study proceeds. 

By mutual understanding it is expected that the results of a previous 

study by Mr. I. M. Buell, of which a preliminary statement has been 

made,a together with the wider studies of Doctor Chamberlin, will 

be combined with these results in a more comprehensive and mature 

discussion. The writer wishes gratefully to acknowledge his indebtedness to Doctor Chamberlin for suggestions and criticisms in the 

preparation of the present paper. The discussion is based principally 

on the drumlins of the Green Bay Glacier.

DISTRIBUTION AND ORIENTATION.

As already indicated, by far the larger number of the drumlins of 

this area belong to-the deposits of the Green Bay Glacier. Though 

generally present throughout the ground moraine of this glacier, 

their distribution is by no means uniform, as will be seen by the map

0 Buell, Ira M., Bowlder trains from outcrops of the Waterloo quartz! te area: Trans. 

Wisconsin Acad. Scl., vol. 10, 1895, pp. 487-509.-

9
10 DRUMLINS OF SOUTHEASTERN WISCONSIN.

(PI. I). Though distributed over a ground-moraine area of approximately 1,325 square miles, part of which is occupied by terminal 

moraine deposits formed during the deglaciation of the area, drumlins occur in but 577 sections of land. Some of these sections contain 

7, 8, or 9 such hills, and one, section 34, Blooming.Grove, near the 

village of McEarland, about 5 miles southeast of Madison, has 10 

distinct drumlins. Where the drumlins are thus crowded, as in a 

school of dolphin backs, the topography becomes very striking.

Ranged as the drumlins are, parallel to the lines of glacial flowage, 

their distribution and orientation in this area shows in a very striking manner the effects of radial deployment of the ice at the southern 

end of the lobe. The deployment of the lobe as a whole was bilaterally asymmetric. This was due to the monoclinal character of the 

Green Bay-Lake Winnebago trough, which it traversed, and to the 

fact that the ice, which surmounted the Niagara escarpment forming 

the east wall of the valley and began to descend the gentle eastward 

slope, Avas stopped by-the opposing front of the Lake Michigan Glacier, which was at the same time advancing up that slope. As a consequence the deployment at the south end of the lobe is eccentric, 

though the curve of the outer moraines is fairly regular through an 

arc of 180°. The extremes of radial deployment shown by the clrnmlin axes within this area are S. 86° W. and S. 75° E., a divergence of 

161° in a distance of 55 miles across the lobe.

Usually the orientation of the drumlin axes is about the same as 

that of the glacial strife observed at adjacent rock exposures. There 

are, however, frequent divergences of 10° to 20°, and sometimes the 

divergence is notable. The following table shows some of the cases 

which have been noted:

Divergent glacial strm of the Green Bay Glacier.

Town.

Burke ..--_--.

Dunn _ ...

Deerfielcl .....

Aztalan ......

Milf ord ......

Sec.

23

23

28

2

20

6

18

' StriiB.

S. 65°-73° W.; S. 72° E'..

S. 23° W.; S. 12°-23°E ..

S. 3°-29° E ..............

S. 85° E3. ................

S. 40°-450 W ............

S 44° W

S. 60° W. ...............

S. 49°-64° W .....,.._....

S. 50° W. ...............

Trend of the nearest drumlin.

S. 30°-40° W.

S. 22° W.

S. 10° W.

S. 15° W.

S. 22°-30" W.

S 12° W

S. 10°-30° W.

S. 15° W.

On rock exposed in a road cnt

through the end of a wellmarked drumlin with trend 

nearly due south.

a Buell, Ira M., Bowlder trains from outcrops of the Waterloo quartzite area: Trans 

Wisconsin Acad. Sci., vol. 10, 1895, p. 494.
. 10

U. S. GEOLOGICAL SURVEY

BULLETIN NO. 273 PL. I

Glacial drift of pre-Wisconsin 

glaciation,probably cf the lowan 

orlillnoiari stage.

Glacial drift of early Wisconsin 

glaciers.

Terminal moraine,possibly of 

an early Wisconsin gla'cier.

Terminal moraines of the 

Lake Michigan Glacierof late 

Wisconsin glaciation, including 

the Delavan lobe.

Terminal moraineso-fthe Green 

Bay Glacier of.late Wisconsin 

glaciation,including borne kameesker tracts of a complicated 

type.

Interlobate kettle moraine of 

the Lake Michigan and Green 

Bay glaciers.

Ground-moraine areas.outwasrv 

gravel terraces,alluvium,and 

deposits of minor glacial lakes 

of late Wisconsin glaciers and 

marshes.

Glacio-lacustrine deposits of 

red clay, sand,and gravel.

Deposits of glacial Lake Chrcago.

Shore lines of glacial 'Lake 

Chicago.

Glacial stria

MAP SHOWING PLEISTOCENE DEPOSITS OF A PORTION OF SOUTHEASTERN WISCONSIN.
DISTRIBUTION AND ORIENTATION. 11

The occurrence of some of these striae which have the more southwesterly trend has been cited as evidence of the advance of an 

ice sheet of an earlier stage of glaciation across this area. There is 

little doubt that the ice sheet which deposited the older drift outside 

the Wisconsin moraines, and which is shown by the trend of the 

striae and the drumlins and by the composition of the drift to have 

moved in a southwesterly direction, really did cross this tract, which 

was later covered by the south end of the Green Bay Glacier; and 

in such an instance as that in the town of Lima, where striae on a 

rock surface exposed beneath the very end of a drumlin diverged 50° 

from the trend of the overlying drumlin, there seems good ground 

for regarding the striations as the product of an earlier glacial 

advance. It should be noted, however, that in some instances the 

divergence is toward the southeast at points where the general direction of the flow of both the earlier and the later ice sheets was 

southwesterly. (See fig. 2, J.} At some exposures, also, there are 

crossing striae bearing both to the southeast and to the southwest on the 

same surface, with no evidence that one set was older than the other. 

Probably mos_t of the divergences noted could be explained as due to 

local deflections of the basal currents of the ice by the inequalities 

of the partially covered rock surface over which the later ice 

advanced. Some of these rock scorings may be the result of abrasion 

early in the advance, before the inequalities of the glacial bed were 

buried in the drift and before the formation of the adjacent drumlin 

was begun. In this region the directions of the glacial flow are 

much more truly shown by the drumlins than by the striae, not only 

because of the greater abundance of opportunities of observation of 

the former, but also because of the evident closer conformity of the 

drumlins than of the striae to a regular system of radial divergence. 

Investigators are sometimes disposed to magnify the importance of 

str'ue in these heavily drift-covered regions as indicators of the directions of glacial flow, forgetting that rock exposures are comparatively .rare, and that at such as do occur stria? are rarely seen continuous for more than a feAv yards, usually but a few inches or a feAv 

feet, at any one place.

On the other hand, the divergence of the drumlins from the regularity of the radial system of arrangement is rare. One instance 

occurs in the town of Farmington (sees. 15 and 22, T. 7 N., R. 15 E.), 

where the axis of one drumlin shows a divergence of 27° westward 

from the nearly meridional trend of the neighboring drumlins. 

(Fig. 2, K.} Another instance occurs northwest of Lake Kegonsa, 

in the town of Dunn (T. 6 N., R. 10 E.), 1-| miles northwest of one 

of the points indicated as showing striae with an easterly deflection. 

At this place, which is on a pre-Glacial upland just west of the preGlacial valley of the Yahara River, one small drumlin has a trend
12 DRUMLINS OF SOUTHEASTERN WISCONSIN".

S. 5 P E., while its neighbors on the southwest have a trend S. 22° W., 

which is normal for the locality.

RELATIONS TO TERMINAL MORAINES.

If we examine the relations of the drumlins to the outer terminal 

moraine, the Johnstown moraine, which marks the limit of the ice 

advance along the south and southwest margins of the Green Bay 

Glacier (PL I), it appears that the process of the drumlin construction was carried on to within distances of 6^ to 13^ miles an average 

of 9 miles of the limit of the advance as marked by the outer margin 

of the Johnstown moraine, and to an average of 7 miles from the inner 

margin of the moraine. On the east and the southeast, where the free 

deployment of the ice was prevented by the opposing front of the 

Lake Michigan Glacier, drumlins occur at distances varying from 1£ 

to 7-J miles from the inner margin of the interlobate moraine, the 

average distance being about 5 miles. In this part of the lobe, in 

addition to the opposition to free advance offered by the Lake Michigan Glacier, the occurrence of a deep pre-Glacial trough excavated in 

the " Cincinnati shale " a and underlying formations, where the protecting cap of the " Niagara -limestone " had been removed, and the 

enormous accumulations of morainal and outwash deposits through a 

belt 4 to 10 miles in width doubtless interfered with the normal development of drumlins and their continuance as unobscured features of 

the landscape.

The relations of the drumlins to the terminal moraine deposits 

formed during the several stages of halt of the ice front in the progress of final deglaciation of the area are shown in PL I, and more in 

detail in figs. 1 and 2. While no exposures have been found showing 

the actual superposition of morainal deposits on drumlins, the areal 

and topographic relations are such as to make it evident that the morainal deposits were superposed on a previously formed drumlin topography. Several instances occur where drumlin heads and considerable parts of the lengths have typical, forms, but where the tails lose 

their identity, merging into morainal deposits with sag-and-swell or 

knob-and-kettle topography. About 2^ miles west of the village of 

Rome (sec. 14, T. 6 N., R. 14 E.), where the morainal belt is very 

slight, having a width of 40 rods to one-half mile, the tails of one or 

two drumlins are lost in the deposit, and the tails of two other small 

ones, otherwise almost completely buried, emerge at the south side of 

the belt, while a long, slender ridge 20 feet in height, barely 20 rods

0 The names Niagara limestone, Lower Magnesian limestone, St. Peter sandstone, Huronian quartzite, Galena limestone, Trenton limestone, Cincinnati shale, Hamilton beds, and 

Potsdam are used in this paper in a strictly quotational sense, from the publications of 

the Wisconsin Geological Survey.
U. S. GEOLOGICAL SURVEY

DRUMUN 2 MILES WEST OF SULLIVAN. WIS., VIEWED F

JJ. TRANSVERSE PROFILE OF THE DRUMLIN SHOWN ABOVE, V
RELATIONS TO TERMINAL MORAINES. 13

in width, sharp, distinct, and straight, emerges from the belt and 

tapers to a point 1 mile to the'south (fig. 1, 0}.- Either the head

j

P:to. 1. Relations of drumlins of the Green Bay Glacier to terminal moraine deposits 

formed during the final retreat of the ice front. Shaded areas represent morainal 

deposits. (Topography from maps of United States Geological Survey and notes 

of the writer.) ,

of this slender drumlin is the small hill directly opposite, at the 

north side of the morainal belt, or the head is buried. The moraine
14 DRTJMLINS OF SOUTHEASTERN - WISCONSIN'.

here is marked by a very gentle sag-and-swell topography. In the

Contour interval 20 feet

PIG. 2. Relations of drumlins of the Green Bay Glacier to terminal moraine deposits 

formed during the final retreat of the ice front, relations of drumlins to eskers, and 

divergent drumlins and striae. Shaded areas represent morainal deposits; heavy black 

lines, eskers; arrow shows trend of glacial striae. Basal outlines of drumlins and 

divisions of crests are shown by broken lines where not adequately shown by contours. 

(Topography from maps of United States Geological Survey and from notes of the 

writer.)

northeast part of the city of Jefferson (fig. 1, A) a drumlin crest
EELATIONS TO BSKERS. 15

heads in a very abrupt hill, which curves around to the west, is somewhat irregular, and appears to be due to the piling of morainal 

deposits against the head of the drumlin. In the town of Oakland 

(T. 6 N.j E. 13 E.) a well-formed drumlin, one of a group, merges at 

its head in the side slope of a great, irregular hill of morainal drift 

(fig. 1, 7i). At several places drumlins are entirely surrounded by 

morainal deposits, but) retain their distinctive forms, and at some other 

places, as just east of the village of Hebron, a gentle sag-and-swell 

topography shows something of a drumloidal ridging, as though 

drumlins were covered by the morainal deposits, the resulting topography being of a rather mixed type.

In some cases hills having fairly good drumlin forms and the same 

trend as the adjacent drumlins are more or less irregular in detail, 

with undulating or slightly serrate crest lines and lobed and gullied 

.slopes, and with the crests or slopes pitted with a few kettle holes. 

Examples of this occur west of the village of Waterloo (sees. 1 and 

12, T. 8 N., E. 12 E.). They appear as having been modified from 

normal drumlins,. probably in connection Avith the formation of the 

slight morainal belts with which they are associated.

RELATIONS TO ESKERS.

Several small eskers occur within the area, and their relations to 

the drumlins and the drumloidal ridges are illustrated in fig. 2, L-Q, 

From the disposition of these sinuous gravel ridges, generally in the 

IOAV tracts betAveen the drumlins and more or less parallel to their 

trend, it would appear that the drumloidal ridging Avas already accomplished before the initiation of the gravel-depositing streams and 

that the streams floAved sufficiently near the base of the ice for the 

moderate relief to control the directions of their floAV. In no case 

within this area has an esker been seen crossing a drumlin. In some 

places eskers lie close to the side slopes of drumlins, swinging against 

the slopes and then aAvay, so as to inclose kettle-like depressions. 

The only case in the drumlin tract Avhere an esker-forming stream 

appears to have crossed a drift ridge is in-section 6, Concord (fig. 

2, (?), and here the relief of the ridge is but 20 or 25 feet. In some 

instances the eskers terminate at or near morainal deposits, suggesting that the streams Avere discharging from their ice channels or 

tunnels when the ice front Avas retreating from the drumlin tract.

DISTRIBUTION OF DRUMLINS RELATIVE TO THE PRE-GLACIAL 

TOPOGRAPHY AND TO THE GENERAL CONFIGURATION OF THE 

DRIFT SURFACE.

. The effect of the pre-Glacial topography upon the distribution of 

the drumlins throughout the ground moraine is not altogether clear. 

The area is so heavily drift-covered that it is not always possible to
16 DRUMLINS OF SOUTHEASTERN WISCONSIN.

determine the configuration of the underlying rock surface. However, by means of the correlation of the records of thousands of wells 

the main pre-Glacial valleys and uplands have been located. In the 

towns of Christiana (T. 6 N., K. 12 E.), Oakland (T. 6 N., R. 13 E.), 

Koshkonong (T. 5 N., R. 14 E.), Lima (T. 4 N., R. 14 E.), Hebron 

(T. 6 N., R. -15 E.), and Sullivan (T. 6 N., R. 16 E.), for example, 

there is considerable bunching of the drumlihs over pre-Glacial highlands, the appearance of bunching being enhanced by their absence or 

scarcity over the adjacent pre-Glacial valleys. (PL I.) Drumlins 

are notably infrequent along the line of the pre-Glacial Rock River 

Valley from Lake Koshkonong northeastward in the towns of Koshkonong, Hebron, and Jefferson, and also through a broad belt, largely 

occupied by morainal deposits, which extends northward from Lake 

Koshkonong to the north limits of the area. The belt is largely, 

though not entirely, underlain by pre-Glacial troughs. On the other 

hand, in some places, as in the vicinity of McFarland (T. 6 N., R. 10 

E.), drumlin groups extend over pre-Glacial uplands and buried valleys without distinction, and, again, in other places, as north of Lake 

Mendota, drumlins are absent or infrequent over tracts which were 

uplands of the pre-Glacial topography. It has not been apparent 

that the large features of the pre-Glacial topography the drift-filled 

valleys and the drift-mantled uplands had any very definite effect 

on the distribution of the drumlins of the last ice invasion, except, 

perhaps, that where the pre-Glacial valleys either were not filled by 

the drift of the earlier glaciers or were reopened by inter-Glacial 

erosion drumlins, if developed, were apt to be buried in subsequent 

fillings of morainal or outwash drift, lacustrine, or marsh deposits. 

Two miles east of Lake Kegonsa (T. 6 N., R. 11 E.) 5 or 6 small 

drumlins lie side by side on the crest of a narrow transverse ridge of 

rock, like packs on the back of a mule.

So far as has been noted, the influence of the several rock formations the limestones, sandstones, shale, and quartzite of the area on 

the formation and distribution of the drumlins is manifested indirectly through the pre-Glacial topography, whose features depend in 

large measure on the character of the rock from which they are 

carved.

There are no great reliefs in the drumlin tract; the drumlins themselves very largely constitute whatever variation there is to the 

gently undulating plain. There are, however, moderate elevations, 

with slopes in various directions. The relations of the drumlins to 

these larger features of the topography, though sometimes interesting, 

do not appear vital to the question of drumlin formation. Drumlins 

occur indiscriminately on the tops, banked against the stoss slopes 

or tailing down the declivities in the lee. Where lying on the stoss
U. S. GEOLOGICAL SURVEY 

A. DRUMLIN ABOUT 2 MILES NORTH OF SULLIVAN, WIS., V

B TRANSVERSE PROFILE OF DRUMLIN SHOWN ABOVE, VIE
DISTRIBUTION OF DRUJMLINS. 17

slopes, the tails sometimes merge indefinitely with the undulations 

of the uplands. A notable example of this occurs southeast of Waukesha, in the towns of New Berlin (T. 6 N., E. 20 E.) and Muskego 

(T. 5 N., R. 20 E.), in the ground moraine of the Lake Michigan 

Glacier, where the troughs between several large ridges of drift, 

which have a driimloidal trend, shallow at distances of one-half to 1 

mile from the heads of the ridges, causing the ridges to merge into 

one continuous upland, whose gentle undulations show the same 

southwesterly trend, but Avhere well-marked drumlins are absent. It 

is as though the edge of the upland itself was fluted by the ice as it 

moved up over the elevated tract. At this particular place, however, 

there are some small rnorainal deposits, which tend to obscure the 

relations to a certain extent.

Not infrequently drumlins occur on or banked against lateral 

slopes, making the uphill slopes short and the downhill slopes abnormally long, thus distorting the basal outlines of what may otherwise 

be symmetrical forms.

DISTRIBUTION OF DRUMLINS RELATIVE TO ONE ANOTHER.

The most common arrangement of the drumlins, where grouped, is 

with their longer axes overlapping side by side; or, if not actually 

overlapping, the axes are rarely in perfect alignment, being either, 

side by side or tandem. Usually as one drumlin begins to tail out 

the head slope of another rises at one side or the other. Those 

neighboring drumlins are generally "separated by distances greater 

than the shorter axes, but sometimes several may be closely dovetailed 

together, though entirely distinct. As the drumlin-forming ice at 

one point was closing about the tail of one individual, it was spreading and riding up over the head of a close-by neighbor. Where so 

closely crowded that the side slopes coalesce, these overlapping groups 

grade into the elongated ridges with overlapping crests, described 

under " Forms of drumlins," p. 22. A notable instance of overlap 

is seen 1 mile northwest of the village of McFarland (sec. 34, T. 7 

N., R. 10 E.), where the slender tail of a small drumlin lies like a 

terrace for 40 rods along the lower slope of a neighbor, tapering to a 

sharp point, while the abrupt head slope at its side rises 30 feet or 

more to the finely shaped crest of the succeeding drumlin. Occasionally this overlapping arrangement is shown by more or less 

distinctly formed crests on a ridge lying obliquely to the direction of 

the glacial movement, as though they had been carved from the ridge 

of drift and the positions of successive overlaps were due to the 

oblique position of the initial drift ridge. Where drumlins are so 

closely set side by side that their lateral slopes coalesce, they pass by

Bull. 273 05 M 2
18 DRUMLINS OF SOUTHEASTERN WISCONSIN.

gradations from twins and triplets to double- and triple-crested 

forms, elsewhere discussed. An occasional arrangement is of a tiny 

drumlin close beside a large one, like the young beside the mother. 

(Fig. 6, A-E.) Rarely two or more drumlins are arranged tandem 

with their axes in almost perfect alignment.

FORMS OF DRUMLINS.

From the limited discussions of class room aiid text-book, students 

are apt to get the notion that drumlins are always sharply defined, 

easily recognizable forms, whose contours vary within but narrow 

limits. As a matter of fact, however, there is considerable variety 

of form and dimensions, with all gradations from the beautifully 

symmetrical, typical forms to drift hills of indefinite shape or orientation. So closely are they related and so thoroughly intermingled 

that it is very largely a matter of the judgment of the individual 

worker in the field as to which ones shall be mapped as drumlins arid 

what shall be regarded as mere undulations of the ground moraine. 

So far is this true that the maps of no two independent workers in 

the drumlin areas would be just alike; indeed, the maps of the same 

worker are apt to show the effects of changes of opinion resulting 

from successive visits to the drumlin area. Such a map as that 

reproduced in PL I, where, in the main, only the more perfect and 

clearly marked drumlins are shown, tells but a part of the story.

Tn-tio:«^iJa^^_^J1j.QU2r]-jQll^ £ne area, jn_\*Jxiok--liarvo-boon aolected hills.

worthy of definite representation as drumlins are hills and ridges of 

drift showing the drumloidal trend more or less clearly, and often 

but a feAv degrees less symmetrical in form and outline than many 

of their neighbors that are admitted to the class. To appreciate the 

drumlin-makirig forces one must have a carefully sketched topographic map of considerable detail and small contour intervals, drawn 

by a topographer who' is at the same time a student of physiography. 

Such a map would show something of the thoroughness with which 

the spreading ice lobe recorded the details of its movement on the 

forms of its ground-moraine deposits.

We may regard as a typical drumlin a hill of glacial drift which 

approximates the form of-a segment of an elongated ovoid, of which 

the widest part of the basal outline and the highest point of the 

crest are not more distant from the stoss end than one-third the 

length of the major axis, and whose major axis is oriented parallel 

to the direction of the movement of the glacier which formed it. 

Though by far the larger part of the drumlins of the Green Bay 

Glacier within 'the area under consideration are variations of this 

type, individual drumlins conforming closely to the type are not 

infrequently seen in different sizes and heights scattered throughout
FOKMS OF DBUMLIKS. 19

the drumlin tract. (Pis. II-VI.) This is true especially if we consider the contours somewhat above the foot of the slopes, as the 

unevenness of the surrounding surface or the spreading out of the 

lower slopes not infrequently gives to a form, otherwise nearly perfect, 

a basal outline which is sometimes distorted as traced on the map. 

There are many drumlins which have beautifully regular crest lines 

and contours, and the symmetrical appearance is still more striking 

where the intervening low areas are occupied by nearly continuous 

marshes, giving the drumlins the appearance of rising abruptly from 

a uniform base. Doubtless this uniformity of base is more apparent 

than real, inasmuch as the marshes contain deposits of peat and muck 

which vary considerably in depth. Since the marsh levels were 

developed subsequent to the formation of the drumlins, by the blocking of the lines of drainage by the transverse belts of the terminal 

moraine deposits formed during the stage of glacial wastage, there 

appears to be no reason for regarding the basal plain on which 

these drumlins were formed as any more uniform in character than 

in the higher parts of the area, Avhere the marshes do not occur.

In figs. 3 and 4 are illustrated 91 variations in size, form, and 

height of the simple, single-crested drumlin. The contours are copied 

from the topographic sheets of the United States Geological Survey, 

with some modifications from the field notes of the writer. The contour interval is 20 feet, and, Avhere necessary, dotted lines are added 

to show the basal outlines of the hills. The forms would be much 

better shown were the contour interval 5 or 10 feet instead of 20. 

The variations are from small elliptical mounds of drift having the 

forms and axial orientations- of true drumlins, but only 5 or 10 feet 

in height and a few rods in length, to hills 140 feet in height and 

ridges 2 miles in length. The ratio of width to length varies from 

1:2 to about 1:19. There appear to be no fixed ratios between any of 

the dimensions, and it would be difficult to determine the average 

of these various forms. The most common heights are 30 to 60 feet. 

Three of the highest forms occur in Windsor (sec. 34, T. 9 N., R. 10 

E.), 1£ miles east of McFarland (sec. 36, T. 7 N., R. 10 E.,) (PL 

IV, B, and PL V, A), and 3 miles east of Stoughton (sec. 2, T. 5 N., 

R. 11 E.). These have lengths of two-fifths to one-half mile, widths 

two-fifths to one-half the lengths, and heights of 100 to 140 feet.

The lengths of the drumlins are extremely variable within the 

limits indicated. An average would probably be somewhat less than 

a mile, perhaps one-half to three-fourths of a mile. As will be seen 

by the map (PL I), there is a notable lengthening of the drumlins 

toward the axis of motion in the lobe, as though in some way related 

to the greater vigor of flow there than elsewhere. These long forms 

are especially abundant in the region of Watertown and Johnson
20 DRUMLINS OF SOUTHEASTERN WISCONSIN. ,

Creek, and where they lie closely side by side, with differences of 40

 *r u / tf V

160 3?0 480 640 rods

Contour interval 20 feet

FIG. 3. Variations in forms and sizes of drumlins of the Green Bay Glacier. Outlines 

of drumlin bases are shown by broken lines where not shown by contours. (From 

topographic maps of United States Geological Survey and notes of the writer.)

to 80 feet between the crests and the bottoms of the intervening
U. S. GEOLOGICAL SURVEY 

A. TRANSVERSE PROFILE OF A DRUMLIN 5 MILES SOUTHEAST OF 

FROM THE NORTH.

Ji. DRUMLIN 2 MILES NORTHEAST OF McFARLAND, WIS., VI
FOBMS OF DKUMLINS. 21

troughs, the resulting topography is very striking. These elongated

Contour interval 20 feet"

FIG. 4. Variations in forms and sizes of.drumlins of the Green Bay Glacier. Outlines 

of drumlin bases are shown hy broken' lines where not shown by contours. (From 

topographic maps of United States Geological Survey and notes of the writer.)

drumlins have heads of the ordinary form, the stoss slopes rising
22 ' DRUMLINS OF SOUTHEASTERN" WISCONSIN.

steeply to the highest points of the crest lines, which are frequently 

not more than 80 to 100 rods from the north ends. The tails, however, are drawn out to great lengths, frequently more than a mile, 

sometimes nearly 2 miles. The major axes are usually straight, and 

the side slopes are remarkably regular. Frequently, they appear 

much more regular to the eye than is indicated by the contours on the 

maps. Some of the smaller of the long forms are remarkably symmetrical and slender, like half torpedoes or cigars, the tails tapering 

to points. Occasionally the crest line sags and a second high point 

occurs midway of the length. Earely the normal form is reversed, 

the stoss end being narrower and its slopes more gradual than the lee.

The variations of the normal fdrm are numerous. Sometimes the 

side slopes are lobed. Sometimes on surmounting what appears to 

be the head of, a normal drumlin the crest is seen to divide, the 

drumlin having two more or less distinct tails. (Fig 5, A~H.} Examples of this double-tailed form occur 1 mile southeast of the village 

of Johnson Creek and 1 mile east of the Ndllage of Rome. 

 Sometimes the crest is divided throughout its length, or, in other 

words, the hill has a double crest. The sag between these crests may 

be but 5 or 10 feet in depth, or it may divide the hill in two (fig. 5), 

resulting in twin forms. An excellent example of the double-crested 

form occurs 80 rods northwest of the village of McFarland (fig. 5. 8}. 

Viewed from the east this hill, which is 60 feet in height, presents one 

of the most beautiful longitudinal drumlin profiles of the whole area 

(PI. V, B] , but viewed from the south the ridge is seen to be about as 

broad as long and to be marked by two crests with a sag 20 or 30 feet 

in depth (PL VI, A). Just south of this is a still broader ridge 

Avith three distinct crests. ' (PI. VI, #, and fig. 5, U.) One and 

one-half miles southwest of the village of Rome three crests .mark 

more nearly separate triplets. (Fig. 5, V.} In all these cases the 

view from the side shows the longitudinal profile of a simple drumlin, 

but a view from the end suggests that a ridge of drift lying transverse 

to the direction of glacial motion was overridden and but partially 

molded to the form of distinct drumlins,.

What may be regarded as a modification of the double-crested 

forms occurs when one of the crests lags behind the other. (Fig. 6.) 

The crests may overlap more than half their lengths^ or they may be 

drawn out more and more into elongated ridges with two or more 

distinct crests slightly out of alignment. Sometimes the lateral shift 

midway in the length of the ridge is very slight, one crest tailing out 

as a new one is gradually developed at its side. The sag separating 

the crests may be very slight, barely enough to distinguish them, or 

it may be 20 to 30 feet in depth. There are a number of these forms 

with overlapping crests, and most, though not all of them, occur in
U. S. GEOLOGICAL SURVEY 

A. TRANSVERSE PROFILE OF DRUMLIN SHOWN IN PLATE IV, B, VIE

B. LONGITUDINAL PROFILE OF A DOUBLE-CRESTED DRUMLIN AT McFARLA
FORMS OF DRUMLTNS. 23

the region of Watertown and Johnson Creek, with the elongated

Contour interval 20 feet

FIG. 5. Double-tailed, double- and triple-crested drumlins, and drumlin twins and triplets. 

Outlines of drumlln bases and division of crests are shown by broken lines where not 

shown by contours. (Prom topographic maps of United States Geological Survey and 

notes of writer.)

drumlin forms. By means of these overlapping crests even greater
24 DRUMLINS OF SOUTHEASTERN WISCONSIN.

lengths are obtained than in the simple forms. Sometimes three or

160 3zo 480 640 rods

FIG. 6. Association of large and small drumlins and development of overlapping crests 

on elongated dr-umloidal ridges. Basal outlines and division of crests shown by broken 

lines where not adequately shown by contours. (Topography from maps of United 

States Geological Survey and notes by the writer.)

four crests are combined in this way and the ridges are drawn out to
U. S. GEOLOGICAL SURVEY 

A. TRANSVERSE PROFILE OF DOUBLE-CRESTED HRUMLIN SHOWN IN PLA

Ji. TRANSVERSE PROFILE OF A TRIPLE-CRESTED DRUMLIN AT McFARLAND
STRUCTURE OF DRUMLINS. 25

lengths of 2 to 4 miles. Not infrequently there are in these variations 

of form strong suggestions that some at least of the drumlins may 

have resulted from the 'erosion of previously formed drift accumulations.

STRUCTURE OF DRUMLINS.

A question that arises concerning the structure and mode of formation of drumlins is, Are the drumlins built up on rock cores? In 

order to obtain data bearing upon this important question, considerable pains have been taken to collect and to correlate the records of 

hundreds of wells on the crests, on the slopes, and in the immediate 

vicinity of the drumlins. The information was obtained very, largely 

from the owners, sometimes from neighbors, and sometimes from 

drillers. While the data can not, of course, be regarded as uniformly 

reliable, yet on the one point of depth to rock there is generally reasonable certainty, and only those records regarded as good have been 

used. The drumlins on which the Avells are situated include all 

sizes and forms; 41 were 10 to 25 feet high, 69 had heights ranging 

from 25 to 50 feet, and in 43 the crests stood 50 to 100 feet above the 

bases. Of the wells on 158 drumlins 37 were on the crests near the 

heads, 46 near the middles, 61 on the tails, and 24 were on the side 

slopes.

The results obtained from the correlation of the well records are 

summarized in the following tables, which include also data concerning: a few drumlins of the Lake Michigan Glacier and a few of the o o

pre-Wisconsin drift.

TABLE :l. Showing thickness of drift below the bases of drumlins in the cases 

where the wells do not reach rock.

Number of wells which"penetrated to the level of the drumlin bases_____ 3

Number of wells which penetrated to depths of 5 to 25 feet^below the drumlin bases ___________ ___- __ 9

Number of wells which penetrated to depths of 25 to 50 feet below the drumlin bases _____________________---______________ 20

Number of wells which penetrated to depths of 50 to 100 feet below the 

drnrulin bases _____________________________ 12

Number of' wells which penetrated to depths of 100 to 240 feet below the 

drumlin bases __________________ _ ___________ 4

The following table shows the relation in the cases in which

.wells drilled on drumlins encountered rock: /

TABLE 2. Sliowmg depths to rock from the bases of the drumlins.

Number of wells which encountered rock at elevations 5 to 25 feet above 

the bases of the drumlins-_____ __ _ _ _______ 4

Number of wells which encountered rock approximately on a level with 

the drumlin bases________..:_______________ 13

Number of wells which encountered rock at depths of 5 to-25 feet below the

bases of the drumlins_____-______-___________ 39
26 DRUMLTNS OF SOUTHEASTERN WISCONSIN.

Number of wells which encountered rock at depths of 25,to 50 feet below the

bases of the drumlins____________i_________ 47

Number of wells which encountered rock at depths of 50 to 100 feet below

the bases of the drumlins_____________________________ 16

Number of wells which encountered rock at depths of 100 to 290 feet below 

the bases of the drumlins____________________ 4

By far the larger part of the drumlins, however, have no wells on 

their crests or slopes, and concerning many wells which do exist no 

information was obtained. A large amount of data has been collected concerning wells in the immediate vicinity of drumlins which, 

while not determining the presence or absence of rock cores, contributes considerable to the probabilities in the case by indicating the general thickness of the drift about the drumlin bases. For 

this determination we have the records of more than 300 wells 

almost all within 80 rods of some one or more of about 350 drumlins. 

Many of them are at or near the foot of the slopes. It is difficult 

to give any satisfactory summary of this mass of data because of the 

greatly varying conditions, but such summaries as have been made are 

presented in the following tables:

TABLE 3. Showing the depths to rock in the vicinity of drumlins.

Number of drumlins in whose vicinities wells show 5 to 25 feet of drift 

over rock_________________________,__________ G7

Number of drumlins in whose vicinities wells show 25 to 50 feet of drift 

 over rock______________________________________ 63

Number of drumlius in whose vicinities wells show 50 to 100 feet of drift 

over rock_________________________________ 46

Number of drumlius in whose vicinities wells show 100 to 300 feet of drift

over rock__________________________________ 10 '

TABLE 4. Showing tlie thickness of drift in the vicinity of drumlins.

Number of drumlins in whose vicinities wells penetrated 20 to 50 feet of 

drift without reaching rock_________________________ 25

Number of drumlins in whose vicinities wells penetrated 50 to 100 feet of 

drift without reaching rock_________________________ 29

Number of drumlins in whose vicinities wells penetrated 100 to 300 feet of 

drift without reaching rock__________,_______:,___,___ 24

In numerous cases wells show considerable variability in the elevation of the underlying rock surface in the immediate vicinity of 

drumlins. This is indicated by the following data:

TABLE 5. Showing variations of the rock surface in the vicmity of drumlins.

Number of drumlins in whose vicinities wells show the depth to rock to 

vary between 0 and 50 feet__________________________ 27

Number of drumlins in whose vicinities wells show the depth to rock to 

vary between 0 and 100 feet_________________ 17

Number of drumlins in whose vicinities wells show the depth to rock to 

vary .between 0 and 280 feet_ .__. .__ - 10
STRUCTURE OF DRUMLTNS. 27

In addition to these there are numerous cases in which rock is 

exposed within distances of 80 rods from the bases of drumlins, 

though there is nothing indicating the presence of rock cores. These 

outcrops occur in all directions from the drumlins and, in numerous 

cases, close to the drumlin bases. The following are the instances 

noted:

TABLE 6. Showing clrumlins near rock outcrops,

Number of drumlins of the Green Bay Glacier within 80 rods of which 

occur outcrops of rock_______________________ 60

Number of drumlins of the Lnke Michigan Glacier within 80 rods of which

occur outcrops of rock__________________________ 5

Number of drumlins of the pre-Wisconsin drift within 80 rods of which 

occur outcrops of rock_ ____________________ =_ 5

While in 17 cases there was evidence that rock lay as high as the 

drumlin bases or rose beneath the hills to heights of 5 to 25 feet, and 

in 70 other cases the rock rose to the surface in the immediate vicinity of drumlins, with no evidence as to how it lay beneath the hills, 

yet there would seem to be little question, from the mass of evidence 

presented, that in by far the larger number of instances concerning 

which any evidence at all was secured the formation of the drumlins 

must have been entirely independent of the elevation or configuration 

of the rock surface beneath.

There are a very few hills having the general drumlin forms where 

the drift appears but to mantle rock hills. One instance of this class 

of veneered hills occurs.on the town line 3 miles south of Madison 

and about 80 rods west of the Chicago and Northwestern Railway. 

Here limestone is exposed in the stoss slope. A few other thinly 

veneered hills of drumloidal "form occur in the region north and 

northeast of Lake Mendota. A well on the stoss slope of a drumloidal hill 1 mile northeast of the village of McFarland shows but 

5 feet of drift mantling the rock surface. About 4 miles southwest 

of the village of Cambridge (sec. 27, T. 6 N., R. 12 E.) there is an 

abrupt drumlin, slightly lobed on one side, within 40 rods of two low 

knolls of limestone. It would not be strange if a similar knoll underlies the drift of the drumlin. As there is no well on the hill, however, the presence or absence of a rock core could not be determined.

On the other side of this question it may be noted that there are 

some ledges or knolls of rock which, it would seem, would have 

formed excellent nuclei on which to have built up drumlins, if this 

was the mode of their formation, but which are now barely covered 

with drift. One of these is a ledge of quartzite in Portland (sec. 35. 

T. 9 N., R. 13 E.), about 5 miles northeast of the village of Waterloo. 

As will be seen in PI. VII, Z?, the strata dip eastward at angles of 

22° to 28°, presenting the edge of the strata to the ice. This ledge, 

which rises 15 feet above the adjacent marsh, was a source of deriva-
28 DftUMLINS OF SOUTHEASTERN WISCONSIN.

tion of drift rather than a nucleus for its accumulation. Being 

closely cut by cross fractures, it afforded an excellent opportunity 

for plucking, and a large amount of bowlder material appears to 

have been derived therefrom. Tailing out several rods in the lee of 

this ledge, until lost in the marsh, is a ridge or train of bowlders 

apparently almost entirely derived from the ledge/itself (PL VII, A), 

but as a cause of lodgment and accumulation of the drift brought to 

it in the base of the ice, for which it would appear excellently 

adapted, this ledge was an almost total failure. While it is, of course, 

impossible to determine the various reasons for this condition, the 

occurrence of so admirable a nucleus without any drumlin, while so 

many drumlins occur in this region without rock nuclei, has a very 

suggestive bearing on the question of drumlin formation. It may be 

said that there is here in the bowlder tail itself an excellent example 

of drumlin formation in an early stage; and this is a suggestion not 

to be neglected. Yet while this nucleus was accumulating its tail, 

other drumlins in the vicinity, with no rock nuclei, matured in form 

with reliefs of 60 to 100 feet or more.

Certain other features in the vicinity of the Portland quartzite 

ledges which might have served as nuclei for drumlins are low 

mounds of bowlders. One .of these is about 500 feet long, 160 feet 

wide, and 16 feet in height above the marsh which borders it on the . 

west. So far as can be seen from the surface, this appears to be composed entirely of quartzite bowlders from the adjacent ledges and 

from the island leglge one-half to three-fourths of a mile northeastward. The major axis has the drumlin trend, and the north end 

resembles the head of a small drumlin. It might, perhaps, be regarded as a drumlin in the early stage of development. Whether it 

has a rock core could not be determined, but 10 rods east naked 

quartzite ledges rise 15 feet higher than this bowlder mound. It 

should, perhaps, be noted that this and neighboring mounds of similar character and the adjacent quartzite ledges occur at the side of 

a considerable drift-filled pre-Glacial valley, a position not especially 

adapted to the formation of drumlins. Some of these quartzite 

ledges are only partially covered with drift, and roches moutonnees 

are finely developed.

In the collection of well data the depths to rock have been quite 

satisfactorily determined, but efforts to learn with any degree of 

accuracy the character of the drift penetrated in farm wells met with 

much less success, so that for a knowledge of the structure of the 

drumlins one is limited almost entirely to the exposures afforded by 

Avagon-road and railroad cuts and other excavations. Nowhere has 

a complete section through the middle of a drumlin been found. 

Though the roads are generally straight over hill and valley, it is rare 

that cuts are more than 15 to 20 feet in depth. Frequently, also, in
U. S. GEOLOGICAL SURVEY BULLETIN NO. 273 PL. VII

A. LEDGE OF QUARTZITE 4 MILES NORTHEAST OF WATERLOO, WIS., VIEWED 

FROM THE WEST.

K. LEDGE OF QUARTZITE SHOWN ABOVE, VIEWED FROM THE NORTH.
STRUCTURE OF DRUMLINS. 29

such cuts as do occur the structure is more or less obscured by vegetation, surface wash, and sliding in such a manner that it can not 

easily be cleaned off. It is therefore not possible to present wholly 

satisfactory data concerning the structure of the drumlins. Such 

observations as have been made, however, are presented. Seventy cuts 

varying in depth from 5 to 60 feet have been examined. In 47 of these 

cuts the material exposed was structureless till of the character common to the area. The matrix of this till varies in character from 

dense, solid clay to very sandy clay, the more sandy clay occurring 

in those parts where the sandstones made large contributions to the 

drift. One feature of the matrix of the till seen in many of these cuts, 

and also of the till in parts of those cuts where stratified beds occur, 

is a more or less definite cleavage of the clay. Under the side slopes 

of the drumlins these lines of cleavage lie parallel to the sloping 

surfaces. This cleavage manifests itself in faint lines not lines of 

bedding along which the clay breaks down, in digging, into more 

or less definite laminae. Where a stone occurs the lines below curve 

downward and up behind the stone, concentric with its surface. 

Those meeting the stone medially end, and those near the top have a 

slight tendency to curve upward over the stone, though less definitely 

than the downward curve of those below. Where another stone 

occurs close above the first the cleavage is apt to be well developed 

bet ween the two. This cleavage is best shoAvn where the material is 

rather fine, stoneless clay, less so where the clay is coarse, and it is 

scarcely noticeable where the clay is very sandy. It, has the appearance of being due to pressure, possibly that of the overriding ice. In 

some places the cleavage planes are accentuated by the deposition 

of a whitish coating of lime by percolating waters. The view shoAvn 

in PI. VIII, 5, was taken in Shields (sec. 21, T. 9 N., E. 14 E.) near 

the side slope of a drumlin 100 feet in height, in a 35-foot transverse 

cut, about 80 rods from the north end. In the deepest part .of the 

cut the cleavage was seen, but less distinctly. This cleavage has been 

observed in a dozen or more drumlins, but it is very readily overlooked unless one has it especially in mind when the examination is 

made. It is very readily obscured by surface wash, and doubtless 

it is much more generally present than the observations would indicate. It is not confined to drumlin sections, but has been observed 

in cuts elsewhere in the ground moraine.

STRATIFIED BEDS IN DRUMLIN SECTIONS.

In 19 of the cuts examined more or less of stratification appeared. 

Frequently this amounted to no more than a bed of sand or sandy 

clay running partly through the section. Frequently patches of 

stratified sands and gravels occur in the till, sometimes showing cross-
30 DEUMLINS OF SOUTHEASTEKN WISCONSIN.

bedding. These usually grade laterally and vertically into the till, 

which in all the cuts constitutes the bulk of the material exposed.

i The relations of the stratified beds in a few cases 

may be mentioned. One instance is the structure 

exhibited by a 25-foot cut through a drumlin onehalf mile south of the village of Windsor (sec. 29, T. 

9 N., R. 10 E.). This drumlin has a length of onefourth of a mile, a width of 100 yards, and a height 

of 40 feet.. The road runs diagonally across the 

hill at a distance from the -head equal to one-third 

of the length. The lower 15 feet of the exposure 

afforded by the cut is of stratified material, largely 

of fine sand, with included thin layers of gravel; 

this grades upward into rather coarse gravel. 

Overlying the stratified drift is. about 10 feet of 

till with a matrix of sandy clay in which the cleavage is well developed.

About 5-J miles north of Edgerton (T. 5 N., R. 

12 E.) there is a gravel pit in the crest of a small 

drumlin, which is developed on the east slope of a 

broad ridge. At the top is a -layer of till which, 

from a thickness of 4 feet near the crest, diminishes 

to 0 on the side slope. Beneath this is 2 to 5 feet 

of fine to 3-inch gravel. The gravel beds do not 

have the curve of the drumlin slope, but are cut 

across by the side slope. Beneath the gravel is 1 

to 3 feet of cross-bedded sand.

In a few cases the stratified beds lie in curves 

more or less concentric with the surface of the 

drumlins. The best illustration of this was seen in . 

a cut through a small drumlin about 2|~ miles northwest of the village of Johnson Creek (SE. | sec. 3, 

T. 7 N., R. 14 E.). The drumlin has a_ length of 

about three-eighths of a mile, a width of 20 rods, 

and a height of 30 to 35 feet. The road crosses the 

hill about 120 rods from the north end, through a 

cut 20 feet in depth. The structure is represented 

diagrammatically in fig. 7. The greater part of 

the material exposed is buff stony till with sandy 

clay matrix. About 7 feet below the crest is a 

definite bed, somewhat less than 1 foot in thickness, and .lying in a curve approximately concentric Avith the curve of the drumlin crest. At the east side this 

bed runs out nearly to the surface of the side slope; at the west

 i

V
U. S. GEOLOGICAL SURVEY BULLETIN NO. 273 PL. VIM

A. CONTORTED BEDS OF STRATIFIED CLAY AND SAND. 

Exposed in a road cut through a drumlin 1 -£ miles east of Hebron, Wis.

B. ROAD CUT THROUGH A NARROW L R U ,Vi L I N 5 MILES NORTHEAST OF 

WATERLOO, WIS.

Showing cleavage developed in the clay matrix of till exposed.
STBATIFIED BEDS IN DEUMLIN SECTIONS. 31

side it is obscured.,by sliding. This bed consists of sand, gravel,

and clay. In places the sand and gravel are distinctly stratified,

at others not clearly 'SO. The clay and sandy clay

show definite lamination. Five to 8 feet below this

is a second bed of sand, gravel, and laminated clay,

with till above and below. Under the west slope

this bed becomes too indefinite to be traced. These

beds are clearly seen on both, sides of the cut. Such

structure as this strongly suggests the building up of

the drumlin by successive stages de novo as a drumlin. This is, however, the only instance of the kind

which has been noted thus far.

In a few cases the stratified beds of sand and clay 

exposed in sections of clrumlins are crumpled as 

though having been subject to lateral pressure. One 

case of such folding of stratified beds,, exposed in a 

transverse, cut through the crest of a drumlin, is 

shown in PI. VIII, A. This drumlin, 1-i miles southeast of the village of Hebron (SE. £ sec. 1, T. 5 N., 

R. 15 E.), has a length of one-half mile, a width of 

about GO rods, and a height of 60 feet. The crumpled 

beds shown occur just below the crest, midway in the 

length of the hill.

The most interesting case of stratification noted in 

a drumlin occurs 1 mile east of the village of Johnson Creek, where the road crosses a drumlin about 

midway of its length and about 20 rods south of the 

highest point. The hill is about three-fourths of a 

mile long, 60 rods wide, and 40 to 50 feet high. The 

cut at this place affords a clean section 20 feet high. 

By far the larger part of the material exposed is 

light-buff till, with a solid clay matrix. In the west 

half of the section on the north side of the cut there 

is considerable stratified sand and gravel disposed in 

undulating layers, as shown in PL IX, />, and fig. 8. 

At one point there is what appears to be an overthrust fold about 12 feet in height. The beds run up 

the west side of the fold and bend over the top, but 

can not be traced continuously downward in the east 

limb of the fold. At the point where they should 

turn downward there are short crumpled layers, and 

belo\v these the beds of the east limb drop down, 

vertically, and, curving gradually out to a horizontal 

position, may be traced thence eastward several yards in. gentle 

undulations, In PI. IX, A, are shown in detail some of the little.
32 DRUMLINS OF SOUTHEASTERN WISCONSIN.

sharp overthrust folds at a point just west of the spade in PL IX, B, 

Intercalated between stratified layers in this section is a bed of till 

3 or 4 feet in thickness. The continuation of these stratified beds 

is seen in the opposite side of the cut about 16 feet south, but the 

fold does not appear there.

While it is possible that the distortion of these beds may have been 

due to settling, resulting from buried masses of ice or from the 

general compacting of the drift, the appearance of the folded and 

crumpled layers is as though they had been subjected to lateral 

pressure. The surface of the drumlin over the distorted beds shoAvs 

no sag such as would have resulted if such a settling took place 

subsequent to the molding of the contour of the hill and after the 

disappearance of the drumlin-forming ice.

One-half mile northwest of the village of Cold Spring there-is a 

drumlin 40 feet in height, 40 rods in width, and tailing out in a 

very long lee slope, being about one-half mile in length. About midway of the length a private road crosses the ridge by a cut 15 feet in 

depth. The loAver 7 feet of the section thus afforded is of very 

stony, grayish till, with rather coarse-grained, sandy-clay matrix. 

Overlying the curved surface of the till is a layer about 1 foot 

thick of nearly stoneless reddish-brown clay of rather fine grain 

showing in places slight indications of lamination. Overlying this 

clay layer is 7 feet of sand, becoming gravelly toward the top. This

layer of oztnd and gravel tllins SOmewftat dOAVTi the side elopes, but it

overlies the lower deposits like a mantle so far as the excavation 

permits examination.

BROWN LOAM AND LOESS COATINGS.

Frequently the exposures show a coating of brownish clay or loamy 

clay, some what'less stony than the till below. Sometimes this appears 

as a deposit more or less distinct from the till, but in most cases it 

looks like the weathered upper part of the till. It usually thickens 

down.the side slopes, being thin or absent at the crest. This thickening down the side slopes has the appearance of being due to the wash 

of the finer material of the weathered layer from the crest and upper 

slopes and its concentration below.

About 1| miles east of Hubbleton station the line of the Chicago 

and Northwestern Railway from Waterloo »to Watertown (sec. 5, T. 8 

N., E. 14 E.) makes a 60-foot cut through the north end of a large 

drumlin. Two-thirds to three-fourths of the section is grassed over, 

but such material as is exposed in the upper part of the cut is solid, 

structureless till, hard to dig with a hammer. The only indication 

of bedding is a slightly sandy band at one point. A deposit of fine, 

stoneless, loesslike, clayey sand mantles the hill at this point. This
t V *

.,.. ; rsia!

.1. ROAD CUT 1 MILE EAST OF JOHNSON CREEK WlS. 

Showing in detail the distortion of stratified beds of clay and sand exposed.

Ji. ROAD CUT THROUGH A DRUMLIN 1 MILE EAST OF JOHNSON CREEK, WlS. 

Showing exposure of stratified sand and clay interbedded with till.
BROWN LOAM AND LOESS COATINGS. 83

mantle thins from 5 feet at the base of the west slope to 1 foot at the 

crest, thence thickening doAvn the east slope to 10 feet at the base. 

This deposit is highly calcareous, except the upper 2£ feet, where 

the lime is leached out. Some of this lime has been concentrated as 

.whitish coatings in the fine cracks. The seepage of water has also 

concentrated the iron at the top of the denser underlying till, making 

a brownish zone there. There is also a brownish zone 1 to 1-| feet 

thick at the top of the deposit, due to weathering.

At the foot of the west slope this deposit is continuous with similar 

sand, clayey sand, and sandy clay composing a series of low, rounded 

knolls. A road cut in this shows a banded structure, some layers 

being more clayey than others. The bands are wavy up and down 

and have not the distinct lamination of water-laid material. It looks 

like a loess or dune deposit blown up from the shore of a lake which 

once occupied the extensive marshy flat along the Crawfish River. 

There is also the appearance of banking of the material on the east 

slope of the drumlin, such as would result from its being bloAvn over 

the crest and lodging on the lee slope.

LITHOLOGICAL COMPOSITION OF THE DRIFT.

As a means of determining roughly the lithological composition of 

the drift composing the drumlins and other features of the glacial 

deposit, a large number of analyses of the drift of the region have 

been made. In making these analyses one hundred to several hundred pebbles have been taken indiscriminately from the drift at 

numerous exposures, and these have been sorted with reference to the 

rock formations from which they were derived and the percentages 

have been noted. Owing to the infrequent occurrence of fossils, the 

determinations were necessarily based on lithological characters. 

The character of the several rock formations within the area is generally so distinctive as to be recognizable to one familiar with them. 

There are, however, gradations from one type to another, so that 

discriminations can not always be made; thus at the best the determinations can be considered biit as approximations of the truth 

Undoubtedly the judgment of different persons would differ considerably as to the identifications of the rock specimens at any given 

exposure. There would, be, little variance, however, in their judgment as to what is of local derivation and what is foreign to the area. 

In consequence of the conditions under which the determinations were 

made care must be taken not to press too far inferences based on mere 

local differences.

The following is a summary of the results of the examinations of

Bull. 273^05 M 3
34 DRUMLINS OF SOUTHEASTERN WISCONSIN.

thousands of rock specimens collected at 250 exposures of the drift 

distributed over those parts of the drift sheets of the Lake Michigan 

and Green Bay glaciers embraced within the area under discussion. 

Of these analyses 28 were made in cuts in drumlins of the Green Bay 

Glacier, 2 in drumlins of the Lake Michigan Glacier, 20 in other parts 

of the ground moraine of the Green Bay Glacier, and 4 in other parts 

of the ground moraine of the Lake Michigan Glacier; 8 were estimates of gravels composing eskers of the two glaciers; 79 were made 

in the several terminal moraines of the Green Bay Glacier, 94 in the 

several terminal moraines of the Lake Michigan Glacier, and 15 in 

the interlobate Kettle moraine, the combined deposit of the two 

glaciers.

In considering the drift of any given part of this area we may 

regard as foreign constituents all those rock fragments for which no 

parent formations are known within the limits of eastern Wisconsin 

in the path of the glacial movement which reached or crossed the 

tract in question. Thus in the area traversed by the Lake Michigan 

Glacier we may regard as foreign all the crystalline rocks, quartzites, 

and sandstones, and all the limestones and shales which can be 

identified as from formations beloAV the " Trenton group " or above 

the Devonian. As a matter of fact, the determinations of the writer 

have warranted the classification of the crystalline rocks, the sandstones, and the quartzites only as foreign material in the drift of the 

Lake Michigan Glacier.

In the drift of that part of the area traversed by the Green Bay 

Glacier all the Paleozoic material limestones, sandstones, and shales 

from the " Potsdam " to the " Niagara," inclusive may be of local 

deriviation. The knobs of " Huronian quartzite " in northwestern 

Jefferson County and southeastern Dodge County > in what is known as 

the " Waterloo area," contributed much quartzite material from which 

it is difficult, without very careful examination, to discriminate 

quartzite material Avhich may be from more distant points, so that in 

the drift of the Green Bay Glacier only the crystalline material 

is regarded as certainly of foreign derivation. Certain crystalline 

knobs occur in eastern Wisconsin, but not in the track of the ice 

reaching the south end of the lobe.

If we consider the 250 analyses made of the drift of these two 

glaciers with reference to the percentages of local and foreign material, it is seen that the foreign material ranges from 2 to 32 per cent, 

the average percentage of foreign material shown by all the analyses 

being 12.63. That the variations are within narrow limits is shown 

by the following:
LITHOLOGICAL COMPOSITION OF THE DRIFT. 35

Resume of analyses of drift materials.

Group 1 ........................ j...... ..................

Group 2 ....-._.._.._-__..._..____.-----------------....--

Group 3. ......... .....--....-..--.----.--...-.--..-.-.-

Group 4 .--..--....--..-......-.......---.--...--.----.--.

Group 5................................................

Total ..!.... .....................................

Number of 

analyses.

172

64

12

1

1

250

Percentages 

of foreign material.

2.00-15.00

15.00-20.00

20.00-25.00.

28.00

32.00

« 12. 63

a Average.

The relative percentage of foreign material in the drumlins of the 

Green Bay Glacier as compared with that in the other features of 

the drift of this glacier is shown in the following table:

Comparative amounts of foreign material in the drift of the Green Bay Glacier,

Drumlins .-.-....---.---......-..-......-..--...--.-.---

Eskers (including one of the Lake Michigan Glacier) 

Other parts of the ground moraine ......................

Number of 

analyses.

28

8 

20

79

Average percentages of 

foreign material.

9.10

. 8.50 

11 14

' 10.98

A similar comparison of the composition of the drift of the Lake 

Michigan Glacier is presented in the following table:

Comparative amounts of foreign material in drift of the Lake Michigan Glacier.

Other parts of the ground moraine ..---..---.--.-.-...-.

Terminal moraines .....................................

Interlobate Kettle moraine (combined drift of the Green 

Bay and Lake Michigan glaciers) .---.--.......-...-..

Number of 

analyses.

2

4

94

15

Average percentages of 

foreign material.

12. 00

15. 60

15. 09

15.95

Judging from the above analyses, it would appear that the drumlins 

and eskers have a lower percentage of foreign material and a correspondingly higher percentage of local material in their composition
86 DRUMLINS OF SOUTHEASTERN WISCONSIN.'

than have the other parts of the ground moraine or the terminal 

moraines. The difference is not notable, however, and it is not clear 

that it may not be more apparent than real. It seems to be clearly 

shown, however, that the drift of the Lake Michigan Glacier contains a little higher percentage of foreign material than that of the 

Green Bay Glacier. This appears in all the comparisons made. 

i Subglacial drift, that transported at or near the base of the ice, is 

much less likely to be transported long distances before its deposition 

than englacial drift, which is carried well up in the body of the ice. 

This proposition is well supported by the phenomena observed in 

this area where, as shown by the above analyses, 85 to 90 per cent of

 the coarser material in the body of the drift is of local derivation, 

Avhile of the bowlders scattered over the surface often in great abundance fully 85 to 90 per cent are of foreign crystalline rock from the 

Canadian regions north of the Great Lakes. This bowlder deposit 

apparently represents the englacial drift let down upon the subglacial 

deposit on the final melting of the ice. As shown by the analyses, 

the drift composing the drumlins, mostly exposed in superficial 

excavations, contains high percentages of local material, as high as, 

if not higher than other parts of the ground and terminal moraines. 

This being the case, we are led to the conclusion that the drift composing the drumlins is subglacial drift and that its accumulation in 

these hills took place at the base or in the lower part of the glaciers.

DISTRIBUTION OF LOCAL MATERIAL IN THE DRIFT.

The predominant local character of the drift composing the drumlins, as also of that composing the other parts of the ground moraine 

and the terminal moraines, is emphasized by the correspondence of 

the predominant constituent of the drift at any given place with 

the underlying rock formation.

The several Paleozoic formations underlying the eastern part of 

the State have general easterly dips and strikes approximately par- 

.allel to the axis of the Green Bay Glacier. Were the drift stripped off 

this part of the State, the beveled edges of the eroded formations 

would be found outcropping in a succession of belts extended in a

 direction generally parallel to the axis of movement of this glacier. 

In crossing the area from west to east, therefore, one crosses successsively the outcropping belts of the Cambrian sandstones, the

 ' Lower Magnesian limestone," " St. Peter sandstone," " Trenton 

limestone," " Galena limestone," " Cincinnati shale," " Niagara limestone," and, near the shore of Lake Michigan, " Hamilton beds " Q of 

the Devonian.

0 See footnote on page 12.
LOCAL MATERIAL IN THE DEIFT. 37

While there is, of course, considerable mixing of the drift derived 

from the several formations, yet careful examinations and analyses 

such as are here presented show very clearly the change in composition of the drift as the successive outcropping belts are crossed. In 

the region of Madison the drift is apt to be sandy and to show much 

of the irregular-textured " LoAver Magnesian limestone " and chert 

derived therefrom. Going eastward the " Trenton limestone " predominates, the drift generally being less sandy except where considerable pre-Glacial valleys have exposed the underlying sandstones. The 

percentage of quartzite also notably increases where the bowlder 

trains, stretching out in the lee of the ledges exposed in the towns of 

Waterloo, Portland, and Shields, are crossed. At some places in 

these trains 15 to 27 per cent of the pebbles are of this local quartzite. 

As soon as the most easterly of the lines of glacial movement which 

crossed these ledges are passed the quartzite element becomes very 

small, what is present very likely being derived from more distant 

sources. In ranges 14 to 17 " Galena limestone " is apt to be the predominant constituent, though it can not always be distinguished from 

the " Trenton " material in the drift, arid the " Niagara limestone " 

begins to appear as a notable component. At some exposures the 

" Cincinnati shale " is present in large amounts, but so soft is this 

shale that its contribution is usually more to the finer material composing the matrix of the till than as recognized pebbles or fragments.

In the drift of the Lake Michigan Glacier the " Niagara limestone " 

is everywhere the predominant constituent, but on going eastward 

toward the lake some other Silurian and Devonian material appears.

LOCAL QUARTZITE DRIFT IN THE DRUMLINS.

(

One element of the local material in the drift is especially noteworthy in this connection because of the possibility of tracing it 

definitely to its source within the area under discussion. This is the 

quartzite material.derived from ledges exposed in the towns of Waterloo, Portland, and Shields, to which reference has just been made. 

This quartzite material is found in trains tailing out in the lee of the 

ledges, in considerable mounds of bowlders in the Adcinity of the 

ledges, in thousands of cords of bowlders scattered indiscriminately 

over the surface of the ground moraine, the drumlins, and the terminal 

moraines, and incorporated in the drift composing all these drift 

features developed in the lee of the ledges. The incorporation of the 

quartzite material is noted in the first good drumlins occurring in the 

lee of the ledges, and decreases thence in amount as the distance 

from the source increases. A few estimates Avere made in cuts in 

drumlins to determine the relati\re amounts of this local quartzite 

material, the estimates being based on the measurement of the area!
38 DRUMLINS OF SOUTHEASTERN WISCONSIN.

extent of quartzite material exposed in the faces of the cuts or on 

the actual amounts of quartzite found in the excavation and sifting 

of a few cubic feet of the drift, or by a combination of the two 

methods. The following are the results obtained:

Table showing percentages of local quartzite in the drift.

Location.

Waterloo Township (sec. 5) .................. ........

Waterloo Township (sec. 16) .:.............. 1 ..'........

Deerfield Township (sec. 25) ... 1 .........:...... .....

Christiana Township (sec. 10) _:..._.:..... ............

Christiana Township (sec. 15) .. ::.... . . . .

Distance from 

ledges.

Miles.

11 _ 91

Si- 44.

113-13*

15 -17

164-18*

Percentage of 

quartzite.

4.26

6.51

3.385

 .024

. 00729

It should be noted in this connection that there is a marked difference between the estimates of the percentages of quartzite composing 

the drumlins as determined in this \vajr and the percentages determined from enumeration of the pebbles. While the estimates in section 5, Waterloo, and section 25, Deerfield, indicated 4.26 per cent and 

3.385 per cent, respectively, as the quartzite content of the drift, 

estimates based on the enumeration of the pebbles and bowlderets 

at the same exposures showed 2Ti per cent and 21 per cent, respectively. This difference may be fortuitous or it may result from the 

hard, indurated quartzite fragments not having suffered sufficient 

comminution within such comparatively short distances of the place 

of derivation to be fully represented in the finer material of the drift, 

so that an examination of the larger pebbles and bowlders shows 

a higher percentage of the local quartzite than an estimate which 

involves the cubical contents of both the coarse and fine material.

ORIGIN OF THE DRUMLINS.

We now come to the consideration of the question, Are the drumlins of the Green Bay and Lake Michigan glaciers wholly the products of the last advance of these glaciers?

If we consider the forms and orientations only, there can be little 

question that the shaping, at least, of the drumlins was done by the 

last glaciers to traverse the area. In very few cases is there any 

divergence of the drumlins from the regularity of the radiating 

system which corresponds to the lines of flow in the deployment of 

the lobe. As already indicated, some of the forms, especially the 

coalesced forms with the overlapping crests, quite strongly suggest 

that they are the result of erosion of previously formed drift deposits,
ORIGIN OF THE DRUMLINS. 39

of fluting and remolding of drift ridges which lay in the path of 

the glacier more or less obliquely to the direction of flow. The 

writer has not, however, been able to determine satisfactorily that the 

drift composing the ridges was deposited by an earlier glacier. Similar suggestions arise also from the occurrence of the double- and 

triple-crested forms which have been described.

. . There can be no doubt that one or more earlier glaciers traversed, 

the tract later occupied by the Green Bay Glacier. This is shown 

by the general distribution of the older drift outside of the later 

moraines, by the composition of this older drift, and by the orientation of striaj and drumlin axes. So, also, as has already been noted, 

there have been observed within the later moraines strise conforming 

more closely to the trend of those of the older drift than to the directions of flow of the Green Bay Glacier. Further, the distribution of 

the quartzite boAvlders in widely dispersed fans leading out from the 

local ledges in more southwesterly directions than those taken by the 

last ice floAv which crossed the ledges indicates one or more earlier 

dispersions.

Beginning at a point about 2^ miles northwest of the village of 

Evansville there is a small- terminal moraine which appears to have 

emerged from beneath the Johnstown terminal moraine of the Green 

Bay Glacier, extends thence about 10 miles northwestward, and again 

disappears beneath the Johnstown moraine. (PL I.) The relations of this moraine show it to be older than the Johnstown moraine, 

yet the degree of weathering and erosion which the drift has suffered 

is not notably greater than that of the later moraine. It is possible 

that this emerging moraine is a terminal of the Green Bay lobe of an 

earlier Wisconsin sheet, formed at the time when the glaciers had the 

wide deployment in Illinois, described by Mr. Frank Leverett in his 

monograph on the Illinois Glacial Lobe," yet this has not been 

demonstrated.

The relations being such, it has not been possible thus far in the 

study to determine whether the local accumulations which have now 

the dr.umlin forms were due wholly to the last advance or in part to one 

or more earlier advances. Nowhere in that -part of the Green Bay 

drift sheet examined has the writer seen drift exposed which he could 

with any certaint}^ regard as older drift, nor has it been possible to 

discriminate the older drift from the later in the records of wells 

collected. In the area of the Lake Michigan Glacier some drift has 

been observed which very probably belongs to one or more of the 

older sheets, and at several places buried vegetal deposits, probably 

to be referred to some one or more of the inter-Glacial horizons, have

»Mon. U. S. Geol. Survey, vol. 38, 1899.
40 DRUMLINS OF SOUTHEASTERN WISCONSIN.

been reported, but none of these occur in the neighborhood of drumlins, and hence do not aid in the determinations desired.

The drift exposed in the drumlin sections corresponds in character, 

composition, and degree of freshness with that in other parts referred 

to the latest drift sheet. The average depth of leaching of the lime 

from the highly calcareous till is about 2^ feet; frequently on the 

crests of the drumlins, where some of the weathered parts are washed 

away, this depth is less than 1 foot. The bulk of the drift appears 

to be bluish till, but to the depths exposed it is usually of a very lightbuff color, sometimes becoming bluish towards the bottom of the 

deepest cuts. Generally a thin zone at the tops of the exposures, 

varying in thickness from 0 to 3 feet, is brownish in color, sometimes 

dark brown or reddish brown, the result of further oxidation and 

staining. Not infrequently included^crystalline pebbles and bowlders 

are disintegrating so that they crumble to pieces under the blows of 

the hammer. A few cases have'been seen where crystalline bowlders 

2 to 3 feet in diameter, in the upper parts of the exposures, were so 

thoroughly disintegrated that they crumbled to coarse sand and could 

be cut with a spade, yet every detail of the surface was sharply and 

clearly shoAvn in the enveloping drift mold. These might have been 

picked up from the surface of an older drift with disintegration 

already in its inception. Where these disintegrating bowlders occur, 

as elsewhere, the bulk of the stony material is fresh and clean in 

appearance and rings sound under the hammer.

The cuts in the drumlins are not usually deep enough or so situated 

as to demonstrate the presence or absence of cores of older drift in 

the drumlins, nor has this been determined from the wells. Indeed, 

it is not certain that the drift of an earlier Wisconsin glacier or of 

the older deposit outside of the moraines could be discriminated from 

the later drift if it were exposed, especially if the zone of riioderate 

weathering had been removed, since the drift of the several sheets 

exposed in southeastern Wisconsin is very similar in-character and 

composition.

Bearing on the question whether the drumlins were formed beneath 

the marginal parts of the ice sheet during a late stage of its action, 

or formed further back and earlier, certain suggestions may be made. 

It has already been shown that the formation of the drumlins preceded the formation of the eskers and inner terminal moraines, and it 

may be noted, further, that the radial arrangement of the drumlin axes 

is in close conformity with the curve of the outer terminal moraine 

which was formed at the limit of the advance, but somewhat less so 

with what appears to have been the curve of the margin of the lobe 

during the stages of the retreat. As the Green Bay lobe was notably 

asymmetric, spreading out on the west nearly twice as far as on the
SUMMARY. 41

east, so, when the melting of the ice occurred, the west and southwest 

margin of the lobe appears to have retreated more rapidly than that 

on the southeast and east; in.fact many miles of ice melted aAvay on 

the west and southwest while the east front was yet pressed snugly 

against the interlobate moraine. The asymmetry of the south end of 

the lobe, which is manifest in the radiation of the drumlins as well 

as in the curve of the moraines, appears to have been reduced by this 

one-sided melting. As a consequence the trend of the drumlin axes 

is not so nearly normal to the innermost of the recessional moraines 

as it is to the moraine which marks the limit of advance. While 

this appears to have been the case, it is not yet demonstrable because 

of the somewhat diffuse character of the inner moraines-. Further 

mapping of these inner moraines may show this more clearly. So 

far as the evidence now in hand can be trusted, the drumlins appear to 

be the product of the advance of the last ice sheet; in their final form, 

at least, they are clearly so. Unfortunately, however, the evidence as 

to the exact method of their formation is very meager and indecisive.

SUMMARY.

A few drumlins occur on the older drift sheet east of Rock River 

and a few on the drift sheet of the Lake Michigan Glacier. They 

reach their finest development in the ground moraine of the Green 

Bay Glacier, there being 1,269 distributed through 577 sections of 

the 1,325 square miles of ground moraine of this glacier in the area 

examined.

The drumlins are, with rare exceptions, arranged in a regularly 

radiating system corresponding to the radiating lines of flow in the 

deploying glacier. They are generally but unevenly distributed 

through the ground-moraine tract, the average limit of their forma^ 

tion being 9 miles within the extreme limit of the glacial advance 

on the south and west, where the deployment of the ice was unrestricted.

The inner terminal moraines formed during the retreat of the ice 

front were deposited indiscriminately over drumlins and other parts 

of the ground moraine.

Where the drumlins and eskers are closely related, it appears that 

the drumlins must have been formed previous to the eskers, and 

that the esker-forming streams must have flowed so close to the 

base of- the ice that the. direction of their floAv was influenced by the 

relief of the drumlins and the intervening low areas.

In some places drumlins a.re bunched together on the pre-Glacial 

uplands; elsewhere they are few or absent on such uplands, so that 

the relation of drumlin formation to the larger features of the preGlacial topography is not altogether clear.
42 DRUMLINS OF SOUTHEASTERN WISCONSIN.

The drumlins are inclined to be bunched rather than distributed 

uniformly over the ground moraine area, and in some parts they are 

closely crowded together, with heads and tails closely overlapping 

side by side.

There is considerable variation in the form and size of the drumlins. Single-crested forms predominate, but double- and triplecrested forms, forms with double tails, and also twins and triplets 

occur. The drumlins generally increase in length toward the axis 

of the movement of the lobe. In this part they are drawn out into 

elongated ridges reaching a maximum length of about 4 miles, and 

are often characterized by several overlapping crests.

In the larger number of cases concerning which determination 

could be made the drumlins appear to be without rock nuclei, and no 

relation between drumlin formation and the configuration of the 

indurated rock surface was detected.

The majority of observed, exposures show only structureless till 

as the component material. The matrix of this till frequently shows 

a distinct cleavage parallel to the curving surfaces of the hills, assignable, perhaps, to the pressure of the overriding ice. Stratified beds 

frequently occur, but only in rare cases was any definite relation to 

the forms of the drumlins observed. In some cases these stratified 

beds are folded and crumpled, apparently the result of lateral pressure. If due to settling, this settling must have occurred before the 

hill was molded to the final drumlin form.

More than 90 per cent of the coarser part of the drift composing 

the drumlins of the Green Bay Glacier appears to be of local derivation, being of similar lithological character to the rock formations 

underlying the area. About 9 per cent must have been brought 

from the Canadian crystalline rocks several hundred miles to the 

north. In the drift .of the Lake Michigan Glacier the foreign 

constituent is a little larger. The several constituents of the local 

drift are distributed through the drumlins and other parts of the 

drift sheet in a manner conforming to the distribution of the underlying rock formations.

Quartzite "material from the ledges outcropping within the area 

is incorporated in the drumlins, as well as distributed over their 

surfaces in large amounts within short distances of the parent ledges, 

decreasing thence with the increase of distance from the sources.

The high percentages of local material in the drumlins indicate 

that the drift was carried at or near the base of the glacier and 

that its concentration in hills took place at this low horizon. The 

general conformit}^ of the distribution of the quartzite material 

incorporated in the drumlins with the bowlder trains due to the last 

glacial advance is an argument in favor of the concentration of the
SUMMARY. ^ 43

\

drift in distinct hills by the same glacier. There can be no question 

that the final forms of the drumlins are the result of the last advance 

of the ice. The writer has been unable to determine whether or not 

any of these drumlins are composed of older drift or whether nuclei 

of older drift occur. The drift exposed is generally fresh, having 

been subjected to but moderate weathering. Nothing has been noted 

indicating that the drift of the drumlins is any older than that of 

other parts of the ground moraine.

The formation of certain eskers and morainic deposits subsequent 

to the formation of the drumlins appears to indicate that the latter 

were the product of the earlier, rather than of the later, stages of 

the ice action, whether such action were constructive or erosive.

Doctor Chamberlin has recently suggested that the possible agency 

of longitudinal crevasses in giving rise to drumlins be tried as an 

additional working hypothesis. Preliminary attempts to test this 

hypothesis by the distribution of the drumlins have been made, but 

owing to the difficulties of determining just where the tensional 

stresses, to which longitudinal crevasses are referable, would be 

located and just how they would affect basal accumulations, it is uncertain whether these first trials have any decisive value; and until the 

subject is more maturely considered it is premature to report upon 

the hypothesis further than to say that the early trials are not especially encouraging.

INDEX.

Page.

Albion, stria; and drumlin near,

trend of _______ 10

Analyses of drift material, re'surne'

of ____________ 85

Aztalan, striae and drumlin near,

trend of _______ 10

Beds, stratified, in drumlin sections _____ __ 29-82, 42

Bowlders, crystalline, disintegration .

of ___________ 40

Brown loam coatings, description of- 32-38

Buell, I. M., on bowlder trains from 

outcrops of Waterloo 

quartzite area____^._ 0, 10

Burke, striae and drumlin near,

trend of ________ I'O

'Cambrian sandstones, occurrence of_ 30

Cambridge, drumlin near, character

of _____________ 27

 Christiana Township, quartzite in,

percentage of _____ 88

" Cincinnati shale," occurrence of__ 30, 87

Clay, cleavage of____________ 20

Clay and sand beds, stratified, character of _________ 31-32 

plates showing__________ 30, 32

Cleavage in drumlins_________ 29

Cold Spring, drumlin near, character of_________ 32

Dearfield, striae and drumlin near,

trend of __.._____ 10

Deerfleld Township, quartzite in,

percentage of__ 38

Devonian rocks, occurrence of____ 30, 37

Drift in vicinity of drumlins, thickness of_________ 26 

local material in, distribution

of _____________ 36-37 

quartzite in, percentage of__ 38

Drift materials, analyses of, re'sume

of _____________ 35

Drift surface, configuration of, relation and distribution 

of drumlins to____ 15-17

Drumlin formation, relation of, to 

pre - Glacial t o p o graphy. vagueness of__ 41-42

Drumlin sections, stratified beds in_ 29-32

Drumlins, cleavagie in_________ 29

deployment of__________ 10

depth of rock from base of__ 25-26

Page. 

Drumlins, depth to rocks in vicinity

of ____________ 26 

distribution of, relative .to one

another ________ 17-18 

relative to pre-Glacial topography and general 

configuration of drift 

surface ________ 15-17 

distribution and orientation of- 9-12 

divergence of, figure showing_ 14 

drift below base of, thickness of 25 

drift composing, derivation of- 42-43 

drift in vicinity of, thickness

of ____________ 26 

forms and size of______ 18-25, 42 

variations in, figure showing _______ 20, 21, 23, 24 

near rock outcrops____ 27 

number of, in the area __ 9, 41 

origin of_l______________ 38-41 

quartzite drift in________ 37-38 

relations of, to eskers_____ 15, 41 

to eskers, figure showing__ 14 

to terminal moraines___ 12-15 

to terminal moraine deposits, figure showing__ 13, 14 

roads through, exposures in__ 28-29 

rock surface in vicinity of, variations of______ 26 

structure of____________ 25-29 

Dunn, drumlins at, divergence and

trend of________ 11-12 

striae and drumlin near, trend

of__________J 10 

Edgerton, drumlin near, description

of_____________ 30 

Eskers, relations of drumlins to___ 15, 41 

relations of drumlins to, figure

showing _________ 14

Evansville, terminal moraine near,

character of__ _____ ' 39

Farmington, drumlin at, divergence 

of, from radial system 

of arrangement____ 11 

" Galena limestone," occurrence of_ 36, 37 

Glacial ice, deployment of, as shown

by the drumlins_____ 10

Glacial drift, lithological composi-

. tiou of _________ 33-36 

Glacial flow, direction of, true

method of showing--!. 11

45
46 INDEX.

Page.

Green Bay Glacier, glacial strise of,

divergence of_____ 10-11

Green Bay Glacier drift, foreign material in, amount of_ 35

" Hamilton beds," occurrence of__ .36

Hebron, drumlin near, clay and sand

beds in, plate showing- 30 

drumloidal ridging at ______ 15

Hubbleton station, drumlin near,

character of______ 32-33

Jefferson, drumlin at, character of_ 14-15

Johnson Creek, drumlins near, description of and figure 

showing _________. 30-31

Lake Kegonsa, drumlins near, character of_________ 16

Lake Michigan Glacier, drift sheet

of, drumlins on____ 41

Lake Michigan Glacier drift, foreign

material in, amount of_ 35

Lima, stria? and drumlin near, trend

of ___________- 10

Loess coatings, description of____ 32-33

" Lower Magnesian limestone," occurrence of__ ___ 36

McParland, drumlins near__ ____ 10 

drumlins near, views of__ 20, 22, 24

Madison, drift in region of, character of_______ 37

Milford, stria? and drumlin near,

trend of ________ 10

Moraines, terminal, description of _ 41 

near Evansville, character of_ 39 

relations of drumlins to_____ 12-15

" Niagara limestone," occurrence of- 36, 37

Oakland, drumlin at ________ 15

Pleistocene deposits, map showing _ 10

Portland, quartzite ledge in, character of __________ 27-28

Quartzite in drift, percentages of__ 38 

occurrence of -____ ___ 37

Quartzite drift, in drumlins_____ 37-38

Quartzite ledge in Portland, character of __________ 27-28

Page. 

Quartzite ledge near Waterloo, views

of _____________ 28 

Roads through drumlins, exposures

in _____________ 28-29 

Rock outcrops, drumlins near____ 27 

Rock River, drift sheet east of, drumlins on ____ _ ____ 41 

Rock surface in vicinity of drumlins,

variations of _____ 26 

Rocks in vicini'ty of drumlins, depths

to ______:_____ 26 

Rome, drumlin near, character of_ 12 14 

" St. Peter sandstone," occurrence of_ 36 

Sand and clay beds, stratified, character of_________ 31-32 

plates showing___________ 30, 32 

Shields, drumlin in, cleavage in ..__ 29 

Silurian rocks, occurrence of_____ 37 

Stpughton, drumlin near, view of-_ 20 

StrifE, divergent, figure showing ___ 14 

Striae, glacial, of Green Bay Glacier,

divergence of_____ 10-11 

Sullivan, drumlins near, views of_ 12, 16 

Sumner, striae and drumlin near,

trend of ________ 10 

Terminal moraines. See Moraines,

terminal. 

Topography, -pre-Glacial, distribution

of drumlins, relation

to ____________ 15-17 

relation of drumlin formation

to. vagueness of____ 41-42 

"Trenton limestone," occurrence of- 36,37 

Troughs, pre-Glacial, occurrence of_ 16 

Waterloo, drumlin near, cleavage in

clay matrix, plate 

 showing ________ 30 

quartzite ledge near, views of_ 28 

Waterloo Township, quartzite in,

percentage of-_ __ 38 

Well records, results obtained from

correlation of_____ 25-27 

Windsor, drumlin near, description

of ____________ 30

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