DEPARTMENT OF THE INTERIOR

Hubert Work, Secretary

U. S. GEOLOGICAL SURVEY 

George Otis Smith, Director

'.t Bulletin 760

\

CONTRIBUTIONS TO THE GEOGRAPHY 

OF THE UNITED STATES

1923-1924

MARIUS R. CAMPBELL

GEOLOGIST IN CHARGE

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1925
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CONTENTS r

[The letters in parentheses preceding the titles are those used to designate the chapters for advance publication]

Page

(A) Pedestal rocks in the arid Southwest, by Kirk Bryan (published Dec. 15,

1923)_.__. --_.._. ...... __..._ ____________-__--__----_--_ 1

(B) The physical features of central Massachusetts, by W. C. Alden

(published Dec. 16, 1924).___________________________________ 13

(C) Erosion by solution and fill, by W. T. Lee (published Apr. 4,1925) _ __ 107

(D) Pedestal rocks in stream channels, by Kirk Bryan (published May 25,

1925)_-__________ ____ _ ________________________________ 123

Index_______________________________________ 129

ILLUSTRATIONS

Page

PLATE I. A, Vermilion and Shinarump cliffs from Lees Ferry, Ariz.; B, Pedestal rock._________________________________________ 4

II. A, Pedestal rock; B, Block of conglomerate with vertical bedding planes_ ______________________________________ 4

III. A, Conical hillock of Moenkopi formation near Lees Ferry,

Ariz.; B, Incipient pedestal rock showing exfoliation...... 4

IV. A, Drip furrow below pedestal rock; B, Stains on under side of

boulder. _ _______________________________ ___________ 4

V. A, Pedestal rock of granite; B, Pedestal rocks and boulders of

erosion__ _________________________________________ 4

VI. Map showing Quaternary geology of the Ware and Quinsigamond quadrangles, Mass_________________________ In pocket.

VII. Diagram showing stage of retreat of the glacial margin in the

Ware and Quinsigamond quadrangles, Mass____________ In pocket.

VIII. A, Dissected plateau of central Massachusetts; B, Wachusett 

Mountain, a monadnock rising above the plateau of central 

Massachusetts._____________________________________ 16

I.. A, Glacial till, a hill of unsorted glacial drift north of Clinton, 

Mass.; B, Dana diorite ("ribbon gneiss") 1 mile southeast 

of Gibbs Crossing, Ware, Mass.___________.__.___ ___ 17

X. A, End of Lower Blase Dale Glacier, Disco Island, Greenland; 

B, Glaciated rock surface near Lower Blase Dale Glacier, 

Disco Island, Greenland.____________________________ 30

XI. Glaciated rock ledge at Clinton, Mass._____________________ 31

XII. A, Crumpled laminated clay, possibly interglacial; B, Esker

south of Clinton, Mass____________________________ 38

XIII. Map of Massachusetts showing distribution of drumlins______ 38

XIV. A, Prospect Hill, a drumlin near North Charlton, Mass.; B,

Drumlin northeast of Gleasondale, Mass.______________ 38

XV. Flood plain and stream terrace.___________________________ 58

XVI. A, Walls of glacial boulders inclosing farm lands near Dana,

Mass.; B, Glacial boulders near Princeton Center, Mass.. 58

XVII. A, Glacial boulder north of Gilbertville, Mass.; B, Perched

boulders 3 miles northwest of Barre, Mass.____________ 58

XVIII. Map illustrating the relations of the ice front to glacial Lake

Nashua at the Clinton stage.___________________________ 70

XIX. A, Kettle holes in sand and gravel south of Clinton, Mass.; B, 

Foreset and bottomset beds of sand plain 3 miles southwest of Clinton, Mass_____--___-___---------------__ 70

in
IV ° CONTENTS

Page 

PLATE XX. A, Cross-bedded sand overlying laminated clay, Still River

Station, Mass.; B, Laminated and crumpled lacustrine

clay, Still River Station, Mass._____________________ 71

XXI. A, B, Potholes in bed of Blackstone River, Mass__________ 104

XXII. A, Barre Falls, Mass.; B, Woolen mill, Gilbertville, Mass. __ _ 105

XXIII. A, Yeitso's Pillar, Carlsbad Cavern, N. Mex.; B, A partition

of onyx___________________________________________ 112

XXIV. A, Stalactites; B, Hattin's Dome and the Temple of the

Sun, Carlsbad Cavern, N. Mex_________________ 112

XXV. A, Stalagmites and column; B, Spring deposits.___________ 112

XXVI. A, Pillars of onyx; B, Twin Domes, Carlsbad Cavern, N.

Mex___!________-____-_____________-____-____-___ 112

XXVII. A, Coralline stalagmites; B, A characteristic scene in Carlsbad Cavern, N. Mex_______________________ 112

XXVIII. Sink holes east of Carlsbad, N. Mex_ ___________________ 112

XXIX. A, Pecos River at Red Bluff dam site, N. Mex.; B, A playa_ 112

XXX. A, Entrance to Carlsbad Cavern, N. Mex.; B, Travertine in

Last Chance Canyon, N. Mex________________ 112

XXXI. A, Devils Top, Deep Creek canyon, 8 miles northwest of 

Spokane, Wash.; B, Incipient pedestal rock, Columbia 

River below China Bar, 9 miles downstream from junction of Spokane River, Wash______ _____ __________ 126

XXXII. A, Pedestal rock in Owens River, Inyo County, Calif.; B, 

Pedestal rock in Gibbon River at Chocolate Cascade, 

Yellowstone Park, Wyo____________________________ 127

FIGURE 1. Map showing location of the Ware and Quinsigamond quadrangles, Mass______-----_--___________________________ 13

2. Map of central Massachusetts showing altitudes above sea level. 17

3. Diagram illlstrating stream changes in central Massachusetts._ 20

4. Map of parts of New England, New York, and New Jersey, 

showing extent, directions of movement, and terminal 

moraines of the last great ice sheet._____________________ 31

5. Map showing area covered by the great ice sheets in North 

America at their maximum extension and the centers of ice 

accumulation _________________________________________ 32

6. Diagram showing probable origin of many kettle holes_______ 45

7. Diagram illustrating formation of kame terraces__________ 48

8. Diagram illustrating the relations of a branching sinuous gravel 

ridge, or esker, near Westboro, Mass., to drumlins, a stream 

valley, and a glacial terminal moraine.___________________ 51

9. Diagram illustrating relations of the receding front of a 

melting glacial globe and a later terminal moraine and outwash terrace to an earlier moraine and earlier terrace._____ 57

10. Diagrams illustrating relations of the receding front of a 

glacial lobe in Nashua River valley to glacial Lake Nashua 

and the pitted terraces, or delta sand plains______________ 63

11. Diagram illustrating relations of the ice front to glacial Lake

Nashua near'the end of the Boylston stage. ______________ 64

12. Map of Eddy County, N. Mex_______.__________._-.__ 107

13. Sketch section through Carlsbad, N. Mex__________________ 109

14. Map and profiles of Carlsbad Cavern National Monument,

N. Mex.________________-____________________________ 111

15. Sketch section of cavernous rocks___-__-_-___-____-----__- 118

16. Sketch section illustrating the filling of caverns.____________ 119
o

CONTRIBUTIONS TO THE GEOGRAPHY OF THE 

UNITED STATES, 1923-1924.

PEDESTAL ROCKS IN THE ARID SOUTHWEST.

By KIRK BRYAN.

INTRODUCTION.

The relative effect of wind and water in the production of the 

characteristic and usually picturesque scenery of arid regions is still 

a moot question. Various criteria that have been put forward as 

indicating wind erosion are of uncertain value. For instance, pedestal 

rocks occurring in arid regions are cited as proof of wind erosion, 

though it has long been known that such rocks are also produced by 

differential weathering in humid regions. 1 The citation in a French 

textbook 2 of the Devil's Table, on the limestone escarpment above 

the Meuse near St. Mihiel, France, as an example of wind erosion 

seems quite certainly erroneous and may serve as an example of 

the length to which faulty interpretation has been carried.

General statements that pedestal rocks, also called " hoodoo rocks," 

"table rocks," "mushrooms," and "stone babies," are formed by 

the sand blast have been published by a number of authors.3 Gregory 4 states that

With, the production of some of the "mushrooms," or "rock babies," to use the 

Navajo term, the wind is chiefly concerned; in the making of others the wind has 

assisted; many of them have attained this shape without the aid of the sand blast.

'Hughes, T. M., On some perched blocks and associated phenomena; Geol. Soc. London Quart. Jour., 

vol. 43, pp. 522-539, 1886. See also Alden, W. C., The Quaternary geology of southeastern Wisconsin: 

U. S. Geol. Survey Prof. Paper 106, p. 41, pi. 10, A, 1918. HopMns, T. C\, Marbles and other limestones: 

Arkansas Geol. Survey Ann. llcpt., vol. 4, p. 343, pi. 17,1890. Wynne, A. B., Notes on some physical 

features of the land formed by denudation: Royal Geol. Soc. Ireland Jour., vol. 1, p. 258,1867.

s Faideau, F., and Robin, A., G6ologie (516mentaire, les phtoonienes actuels, p. 8, Paris, 1902.

8 Walther, Johannes, Das Gesetz der Wiistenbiklung, 2d ed., pp. 17.5-177, Leipzig, Quelle & Meyer, 1912.

Endlich, F. M., On some striking products of erosion in Colorado: U. S. Geol. and Geog. Survey Terr. 

Bull. 4, pp. 831-864,1878. The views expressed in this paper are very moderate.

Strceruwitz, W. H. von, Trans-Pecos Texas: Texas Geol. Survey,Fourth Ann. Rept., for 1892, p. 1-15, 

1893.

La Touche, T. D., Geology of western Rajputana: India Geol. Survey Mem., 35, p. 11, pi. 1, fig.2,1902.

Hill, R. T., Growth and decay of the Mexican Plateau: Eng. and Min. Jour., vol. 85, p. 688,1908.

Blackwelder, Eliot, Conozoic history of the Laramie region, Wyo.: Jour. Geology, vol. 17, p. 443,1909.

Woodward, H. P., A geological reconnaissance of a portion of the Murchison gold field: Western Australia 

Geol. Survey Bull. 57, pp. 31-32, figs. 20, 21, 22,1914.

Hume, W. F., The physiography of arid lands (as illustrated by Desert Egypt), Geol. Mag., new. ser. 

dec. 6, vol. 1, p. 422,191-1.

Hobbs, W. H., The crosional and degradational processes of deserts, with special reference to the origin 

of desert depressions: Assoc. Arn. Geog. Annals, vol. 3, p. 35,1917.

'Gregory, H. E., Geology of the Navajo country a reconnaissance of parts of Arizona, New Mexico, and 

Utah: U. S. Geol. Survey Prof. Paper 93, p. 138,1917.
2 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1&23-1924.

In the present paper observations made in 1921 in northern 

Arizona and central New Mexico are recorded, and those made during the same and previous years in southern Arizona are introduced 

for comparison. Near Lees Ferry, in northern Arizona, an arid 

region, where wind work is notable in certain areas, the method of 

formation of some pedestal rocks by rain wash and differential erosion 

was determined with considerable precision. The conclusion reached 

is in accord with that of Gregory that even in i an arid region the 

mere presence of pedestal rocks can not be cited as evidence of wind 

erosion. Definite proof must be brought forward not only that 

7 the marks of wind scour are present on the rocks but that this process 

has been the dominant one in the production of these peculiar forms.

* 

PEDESTAL ROCKS NEAR LEES FERRY, ARIZ.

GENERAL RELATIONS.

Lees Ferry, on Colorado River, 132 miles north of Flagstaff, Ariz., 

has an elevation of 3,100 feet, and a climate warmer and drier than 

most of the surrounding region. The available weather records 

indicate that the average rainfall in the region up to an altitude of 

4,000 feet is probably less than 6 inches. 5

Lees Ferry is in the angle between the north-south Echo Cliffs and 

the east-west Vermilion Cliffs. The geology has been described by a 

number of authors. 6 Only the relations ,of the Shinarump conglomerate, 40 feet thick, and the underlying Moenkopi formation, a 

gypseous red sandy shale about 500 feet thick, concern the subject 

of this paper, for the pedestal rocks are formed of blocks of Shinarump 

conglomerate resting on the Moenkopi formation. The blocks lie 

at the base of the Shinarump cliffs, secondary cliffs at the foot of the 

great cliffs formed by the massive sandstones of Jurassic age (Navajo 

and Wingate). For 13 miles west from Lees Ferry at the base of the 

Vermilion Cliffs and for 10 miles south from the ferry at the base 

of Echo Cliffs the Shinarump cliffs are well developed. Great blocks 

of the Shinarump conglomerate are undermined by the erosion of the 

Moenkopi and fall to the foot of the cliffs. 7 The erosion of the 

Moenkopi is effected in part by rain wash, but largely by temporary

& For compiled weather records see Gregory, H. E., The Navajo country a geographic and hydrographic 

reconnaissance of parts of Arizona, New Mexico, and Utah: U. S. Geol. Survey Water-Supply Paper 380, 

pp. 49-68,1916.

6 Eowell, E. E., U. S. Geog. and Geol. Surveys W. 100th Mer. Rept., vol. 3, pp. 265-297,1875. Gilbert, 

G. K., idem, pp. 63-85, pi. 11.

Dutton, C. E., Tertiary history of the Grand Canyon district: U. S. Geol. Survey Mon. 2, p. 205,1882.

Davis, W. M., An excursion to the Grand Canyon of the Colorado: Harvard Coll. Mus. Comp. Zool. 

Bull., vol. 38, pp. 108-199,1901; vol. 42, pp. 1-40,1903.

Gregory, H. E., op. cit. (Prof. Paper 93), pp. 114-115,135-136.

For a geologic map, see Bryan, Kirk, Discussion of'' Tentative plan for the construction of a 780-foot 

rock-fill dam on Colorado Biver at Lees Ferry," by E. C. LaRue: Am. Soc. Civil Eng. Trans., vol. 86, pp. 

228, 240-1923.

' Davis, W. M., op. cit., p. 134, pi. 2.
PEDESTAL ROCKS IF THE ARID SOUTHWEST. 3

streams that cascade over the edge of the conglomerate and form 

deep vertical or nearly vertical channels in the shale. At favorable 

places also ground water seeps through the Moenkopi, as at Bitter 

Spring and a seep at Soap Creek. Because of the large content of 

gypsum and other soluble salts in the Moenkopi, this ground water 

is doubtless effective in undermining and sapping the cliffs. The 

principal erosive work in the area is accomplished by the ordinary 

weathering processes due to rain and streams, though there is some 

wind work, as described below.

FORMATION OF THE PEDESTAL BOCKS.

Blocks of conglomerate obviously derived from the cliffs not uncommonly stand on pedestals of Moenkopi shale (Pis. I, B; II, A; 

III, B; IV, A and B). These rocks were noted by Gilbert, whose 

explanation is discussed in a later paragraph, and are mentioned 

by Davis.

It is noticeable that in all the pedestal rocks the bedding planes of 

the conglomerate blocks are horizontal, or nearly so. Blocks that 

lie with the bedding planes in a vertical position rest on cones of shale 

veneered with pebbles derived from the weathering of the conglomerate (PL II, B). There are present also conical hillocks ve-, 

neered with similar pebbles apparently derived from blocks that have 

long since been destroyed by weathering (PI. Ill, A) . The conclusion 

seems to be obvious that when a block of conglomerate comes to rest 

with the bedding planes in a vertical position weathering loosens 

the cement rather rapidly, freeing the original pebbles. If, however, 

the bedding planes are nearly or quite horizontal the cement is 

resistant to weathering, brown crusts form on the surface, and the 

rock breaks up thereafter largely by exfoliation (PI. Ill, B) .

About 3 miles southwest of Lees Ferry, on a bench about 400 feet 

above the river and at the foot of the Vermilion Cliffs, north of the 

Marble Canyon, is a remarkable group of pedestal rocks. Here on 

the afternoon of July 14, 1921, there was a hard shower of an hour's 

duration during which it was possible to observe the effect of rain 

on pedestal rocks.

During the first 15 minutes of the shower the wind was easterly, 

and under both the large rocks (Pis. I, B, and II, A) it was dry even 

for a man seated on horseback. At the end of that time water began 

to drip from the east side of the blocks, and then, the wind shifting 

to the west, a heavy drip began on that side, though without stopping 

that on the east side. The water formed a film that extended from 

the overhang about 3 feet onto the under side of the rock. From 

this place a curtain of falling drops, or "drip curtain," 8 extended all

8 " Drip curtain " is a useful term to define the somewhat discontinuous sheet of drops and threads of water 

that falls from any overhanging rock. It is strictly analogous to tho sheet of water that falls from the eaves 

Of & house.
4 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

around the pedestal. As the rain continued the film of water crept 

farther down the underside of the block until finally it reached and 

began to wet the top of the pedestal. These conditions were observed at both the large rocks (Pis. I, B, and II, A) and, with modifications, on numerous smaller and less perfect pedestal rocks.

The drip curtain forms on large blocks about 3 feet inside the outer 

limit of the block, though this distance is modified by the direction 

of the wind, the form of the block, and the texture of the rock. 

Under some rocks generally and under others locally the drip curtain 

is well denned and constant in position, but drops fall inside the main 

curtain at certain places, and secondary curtains may form. Where 

the drops strike the ground all the fine particles of earth are churned 

into mud and carried off in suspension by little rivulets; the coarser 

pieces, either fragments of thin sandstone from the Moenkopi or 

rounded pebbles from the Shinarump, remain and form a pavement 

that resists the action of the falling drops. The removal of fine 

material, however, forms a slight depression or "drip furrow" 

around the pedestal similar to that formed by the drip from the eaves 

of a house (PI. IV, A). Little rivulets fed by rain water falling on 

the adjacent ground take advantage of these drip furrows and either 

deepen them or fill them with material brought from other places, 

which later may be removed by the drip. Under the larger rocks 

the drip furrow is not generally a continuous annular depression but 

forms part of the channels of these near-by rivulets.

The film of water that creeps over the surface of the rock feeds the 

drip curtain and then goes beyond it, finally reaching the top of the 

pedestal. If the rain should last long enough the film of water doubtless would cover the .pedestal. During the shower in which these 

observations were made all the water that reached the top of the 

pedestal was absorbed there in a layer of loose material or soil 3 to 4 

inches thick. Thence it doubtless penetrated into the shale below. 

Compared to the total amount of water that falls on the top and sides 

of the block during such a rain the amount that reaches the top of 

the pedestal is very small, but it has a definite effect in assisting in the 

weathering of the pedestal and in carrying away the products of 

weathering.

The action of'rain in the formation of these pedestal rocks seems 

clear. The greater part of the water shed from the block falls in a 

drip curtain about 3 feet inside the periphery, forming a drip furrow 

from which temporary rivulets carry away the finer material. Rain 

wash from adjacent areas tends to concentrate in these furrows and 

assists in the process of transportation. Larger fragments doubtless 

lie in the pavement for a long time until they weather into particles 

of transportable size or until some larger stream by lateral planation 

moves into the area and carries them away. But durable fragments
U. S, GEOLOGICAL SURVEY BULLETIN 7GO PLATE I

A. VERMILION CLIFFS FROM LEES FERRY.

View down Colorado River at head of Marble Canyon. Platform of Kaibab limestone is 

surmounted by the Shinarump cliffs, and these in turn by the great Vermilion Cliffs. 1 

Pedestal rocks of Plates I, A, and II, B, at the locality marked P. -

B. PEDESTAL ROCK.

Block of Shinarump conglomerate on a pedestal of Moenkopi shale. Note the details of erosion 

in the cliff of Moenkopi formation in the background, the abrupt break in slope to the pediment developed on similar material in the foreground, and the small number of blocks at 

the foot of the cliff. The block of the pedestal rock is marked with stains from the lilm 

of water which covers it in whole or in part during rains.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE II

A. PEDESTAL HOCK.

Block of Shinarump conglomerate resting on a pedestal of Moenkopi slialo. Note sloping 

plain (pediment), developed on Moenkopi formation, with a stream channel in foref

-ound, Marble Canyon cut through the Kaibab limestone in the middle ground, and 

cho Cliffa in the background.

B. BLOCK OF SlllNAUUMP CONGLOMERATE 

PLANES.

WITH VERTICAL BEDDING

Rests on subconical hillock of Moenkopi formation veneered by gravel resulting from the 

disintegration of the block. The slight hollow on the left of tlie block is due to incomplete 

protection from drip by the gravel. Marble Canyon is concealed in the light-colored area 

(Kaibab limestone) in the middle ground. Echo Cliffs with fret of Shinarump cliffs at the 

base rise in the backsrouiid.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE III

A. CONICAL HILLOCK. OF MOKNKOPI FORMATION NEAH LEKS FURRY,

AHIZ.

The Mocnkopi formation here is a sandy shale, covered with gravel resulting from the 

disintegration of a block of Shinarump conglomerate.

11. INCIPIENT PHDE8TAL HOCK SHOWING EXFOLIATION.

Shows also cross-bedding of the Shinarump, irregular crusted surface, and a small pit due to

solution of cement.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE IV

A. DRIP FURROW BKLOW PEDESTAL ROCK.

Surfncc of the ground covered with scales of sandstone from the Moenkopi formation. The 

pedestal has vertical joint cracks widened by solution of veins of gypsum and is marked by 

white patches of salts derived from its interior.

B. STAINS ON UNDI3R SIDE OF BOULDER.

Showing that the film of water formed during rains extends to the top of the pedestal, which 

. is marked by white patches due to the efflorescence of salts.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE V

A. PEDESTAL ROCK OF GRANITE.

Two miles northwest of Oracle, Ariz- Note vegetation of calclaw, yucca, cactus, small

bushes, and grass.

B. PEDESTAL HOCKS AND BOULDEHS OF KKOSlOlN.

Tijeras Canyon, Sandia Mountains, N. Mex. Note the rough surfaces of the granite boulders 

and the influence of joint planes on the shape of boulders. The closely grazed grassy 

foreground is part of the slope to the old valley at the right. The mountain slope of the 

background has numerous boulders of erosion and pedestal rocks.
PEDESTAL ROCKS IN THE ARID SOUTHWEST. 5

are not numerous, for the blocks of the pedestal rocks weather 

slowly, as shown by their smooth brown and incrusted surfaces.

Those blocks which are so placed that the bedding planes are verti-. 

cal have no such smooth crust. Their surfaces are rough and are 

bright in color. Pebbles and fragments of the matrix are easily 

detached with the fingers. The blocks shed numerous durable fragments, which, lying at the bases of the blocks, protect the underlying 

shale from the drip. Doubtless also the rough surfaces retard the 

movement of water and more of it penetrates into the rock. Light 

rains probably cause no drip from such blocks. For these reasons 

rocks with vertical bedding planes stand on conical hillocks, whose 

slope is determined by the ability of entirely local rain wash to erode 

the shale under the protecting film of gravel. That the type of 

surface characteristic of the Shinarump blocks enables the film of 

water to extend to the under side of the block for 3 feet before falling 

probably explains the fact that only large blocks much more than 6 

feet in diameter stand on pedestals. The block about 6 feet in 

diameter shown on the left in Plate II, B, has so small a pedestal that 

its fall to the left seems imminent.

The pedestal, if formed wholly by the action of the drip curtain, 

should be as large as the annular ring of the drip furrow. However, 

most-of the pedestals are slimmer, like those of the rocks shown in 

Plates I, B, and II, A. These pedestals and the pedestals of many 

other rocks have been eroded more than 3 feet back of the drip 

curtain. They have almost vertical sides, and there is no talus or 

slope of loose material between the pedestal and the drip furrow. 

These features may be explained by the action of the film of water 

that extends inside the drip curtain. In the rain of July 14, 1921, 

the film merely moistened the top of the pedestal, but in great 

storms water may completely cover it. Even a small amount of 

water is effective in the erosion of the Moenkopi formation, for it is 

sandy and porous, has well-defined vertical joints, and is impregnated 

with gypsum and other soluble salts. A small amount of water 

applied at the top and soaking into the pedestal is sufficient to open 

the joints and bring to the surface the soluble salts, as shown in Plate 

IV, A and B. The shale not only crumbles and "slacks" at the 

surface but sloughs off along the vertical joints. The vertical sides 

of the pedestal may therefore be explained by the work of the film of 

water due to ordinary storms, but it is not certain that even great 

rains would produce enough water for the film to cover the entire 

pedestal and run off at the foot in large enough quantities to carry 

away the talus. The direct erosive action of wind-driven rain, 9 the 

splash from the drip furrow, and the lateral migration of rivulets

»Kinahan, G. H., Valleys and their relation to fissures, fractures, and faults, p. 83, London, 1875. 

Attributes part of erosion of pedestal rocks of Devonshire to wind-driven rain.
6 CONTRIBUTION'S TO GEOGRAPHY OF UNITED STATES,, 1923-1924.

must therefore be called upon for the removal of the talus. It is also 

possible that wind scour may play a part in the removal of talus, 

though no tangible evidence of such scour was found.

The foregoing description and analysis seem to indicate that rain 

and the ordinary processes of weathering are competent to form 

pedestal rocks, and this conclusion is corroborated by the contrast 

between the bases of blocks with vertical and those with horizontal 

bedding planes.

POSSIBLE EFFECTS OF WIND WORK.

Prior to the observations just described the writer made a journey 

along the base of the Vermilion Cliffs and noted the number and 

characteristics of pedestal rocks, although the rocks observed during 

the rain of July 14 were not visited. No considerable rain had fallen 

here for more than a year, and hence mechanical processes of erosion 

and wind abrasion had had full sway for a long period. Neither the 

pedestals nor the ground beneath them were grooved by wind action, 

but many pedestals had been used as rubbing posts by cattle, who 

love " the shadow of a great rock in a weary land," and in this manner 

a small amount of erosion had been accomplished, but the cow dung, 

much of it pulverized by trampling, had not been removed by wind 

action. No wind polish was observed on the blocks of Shinarump 

conglomerate nor on flakes of hard sandstone from the Moenkopi.

These observations are not in accord with those of Gilbert,10 who 

on visiting this locality in 1871 was much impressed by wind work. 

He ascribes a large part of the erosion of the Moenkopi to wind scour 

and considers that the pedestal rocks are formed by the excavation 

of the shale around the base of each rock by wind action. Davis,11 

however, mentions the rocks and says that they are isolated by the 

recession of the cliffs. He explains, at some length, the recession of 

the cliffs in terms of water action. It is evident that Davis did not 

consider wind action effective in molding the surface at the base of 

the cliffs.

In many places near the pedestal rocks the writer observed evidence 

of wind action in accumulations of wind-blown sand. Skirting the 

cliffs at the base of which stand the pedestal rocks and extending 

down to the Kaibab limestone, which forms the rim of Marble Canyon, 

is a sloping plain or pediment, 12 developed largely on the Moenkopi 

shale and graded to the top of the Kaibab as a local base-level. The 

major streams, such as Badger and Soap creeks, have, however, 

intrenched themselves in canyons that extend from Marble Canyon 

to the base of the cliffs. It is only the small streams and the rills and

10 Op. cit., p. 84, pi. 11. 

« Op. cit., vol. 38, p. 134, pi. 2.

18 Bryan, Kirk, Erosion and sedimentation in the Papago country, Ariz.: U. S. Geol. Survey Bull. 730^ 

pp.52etseq.,1922.
PEDESTAL ROCKS IN THE AEID SOUTHWEST. 7

rivulets that during and after rains flow over this sloping pediment 

toward the river. Part of the pediment is mantled with wind-blown 

sand from a few inches to 3 feet deep. Between Badger and Soap 

creeks and between Soap Creek and Jacobs Pools the sandy areas are 

extensive. It is noticeable, however, that the sand has accumulated 

in a more or less continuous blanket at some distance from the 

Shinarump cliffs, and the pediment at the base of the cliffs is relatively 

free from sand, showing only windrows of sand a few feet long and 6 

inches to a foot wide and little piles of sand near loose rocks, behind 

bushes, and in the channels of rills. The surface also is generally 

covered by pebbles mostly loosened from the Shinarump conglomerate 

and flakes of thin sandstone from the Moenkopi formation. During 

the long dry period before this journey the wind had been active on 

the slope, but the work it accomplished had not been large. Only in 

a few places was the relatively soft ground scarred or grooved, and in 

no place had the channel of rills been obliterated, though months had 

elapsed since they carried any water. The windrows and piles of 

sand had more or less imperfectly filled some of these channels, and 

to such damming by wind-blown sand some of the lateral migration 

of streams on pediments and alluvial slopes may be safely attributed. 

There was a general cover of pebbles and blocks of sandstone, of the 

type usually called a " desert pavement." The value of such pavements as evidence of wind erosion has been much exaggerated. In 

favorable places similar pavements can be seen in humid lands, as, for 

instance, on some of the gravelly terraces near Washington, D. C. 

The pavement can be produced by flowing water 13 or by ram wash, 

which removes the fine and leaves the coarse material. The latter 

process was observed during the shower of July 14. The existence of 

a "desert pavement" in such a place is not proof that the wind is 

active; it may only be proof that wind action has been too feeble to 

cover with sand or destroy a pavement produced by rain wash during 

the last rain.

The foregoing review of wind action in this locality shows that 

it is a comparatively minor force in erosion here, though it is effective 

in other parts of the Lees Ferry region. 14 Its principal work has 

been to accumulate sand in intercanyon areas, where the sand can 

not with the present absence of stream action be easily removed by 

streams. The wind has also assisted in the diversion of rivulets on 

the pediments at the foot of the cliffs.

PEDESTAL ROCKS IN SOUTHERN ARIZONA.

In a number of localities in the drainage basin of San Pedro River, 

in southern Arizona, isolated rocks ranging in shape from masses 

of boulders to pillars and pedestal rocks are common. The pedestal 

rocks differ from the other rocks only in having overhanging sides.

« Free, E. E., The movement of soil material by wind: U. S. Dept. Agr. Bur. Soils Bull. 68, p. 32,1911. 

'«Bryan, Kirk, Wind erosion near Lees Ferry, Ariz.: Am. Jour. Sci., 5th ser., vol. 6, pp.291-307,1923.
8 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

The origin of the overhang is not wholly clear, but evidence is presented below to show that these pedestal rocks, like the pedestal 

rocks of the Lees Ferry region, can not be ascribed to wind erosion. 

These rocks occur northwest of Tombstone; at Stronghold Canyon, 

on the west side of the Dragoon Mountains; in Texas Canyon, in the 

south end of the Little Dragoon Mountains; north and west of Oracle; 

and at various places in the Tortilla Mountains north of ° Oracle. 

In all these localities the surface is underlain by coarse-grained granite 

with characteristic widely spaced joints.

The climate is generally mild, though freezing weather is common 

in winter. There is a double rainy season: the winter rains are 

gentle and are due to general storms; the summer rains are violent 

local showers. The rainfall is sufficient to maintain a thin cover of 

perennial grass on most of the surface at all the localities. The 

Stronghold Canyon, Texas Canyon, and Oracle localities lie at the 

dry timber line, which in this region is the contact zone of the desert 

scrub, mesquite, catclaw, etc., and the liveoak and manzanita woodlands. The localities near Tombstone and in the Tortilla Mountains 

lie in the zone of desert scrub.

The available weather records are summarized below:

Precipitation at three stations in San Pedro Valley, Ariz. 

[As compiled to 1913 by the United States Weather Bureau.]

Station.

Station.

Altitude 

(feet).

4,550

4.500

2,200

Number 

of years.

17

22

25

July.

3.31

2.47

2.13

Jan.

0.77

2.01

1.31

Aug.

3.61

3.64

2.70

Feb.

1.30

1.95

1.55

Sept.

1.64

1.33

1.23

Mar.

0.86

1.57

1.03

Oct.

0.52

.79

.92

Apr.

0.33

.59

.52

Nov.

0.80

1.82

.96

May.

0.24

.36

.36

Dec.

0.75

1.73

1.32

June.

0.41

.37

.26

Mean 

annual.

14.54

18.63

14.29

Under the prevalent climate the granite of these localities breaks 

up largely through the mechanical processes of weathering and tends 

to produce castellated forms. There is, however, sufficient moisture 

to make chemical action more pronounced than in the more arid 

portions of Arizona.15 The pedestal rocks and similar isolated forms 

occur in places where pediments have been dissected and new pediments are in process of formation, at a lower level, not more than 

150 feet below the old surface.

With variations in detail the origin of the pedestal rocks in these 

localities is similar, and the example shown in Plate V, A, will serve

i&Bryan, Kirk, Erosion and sedimentation in the Papago country, Ariz.: U. S. Geol. Survey Bull. 730, 

pp. 37-52, 1922.
PEDESTAL ROCKS IN THE ARID SOUTHWEST. 9

as a model for all. This rock stands, with numerous similar monoliths, on the pediment northwest of Oracle, a plain of erosion and 

transportation formed by streams that flow from the north end of 

the Santa Catalina Mountains. At this place the direction of flow 

is northwestward to Big Wash, whence, in time of flood, water finds 

its way south and then west into Santa Cruz River. The pediment 

has been formed by the dissection of an older pediment of similar 

form and somewhat greater extent, formed by the same streams when 

they flowed at a level about 150 feet higher. In dissecting this older 

pediment the streams first cut narrow, steep-walled canyons, which 

grew headward by the erosion of falls. Later these canyons widened, 

tributary canyons were cut, and mesas and hills were isolated in the 

interstream areas. In this locality most of these residual hills have 

been reduced to masses of boulders or to monoliths.

That masses of boulders and monoliths should be left by erosion 

in places where the joints of the granite are widely spaced is not 

surprising, but the not uncommon mushroom shape seems to be 

due to special causes.

The soil on this pediment is a gravelly loam, composed of debris 

of the granite with many grains of feldspar, in part a residual soil, 

but mostly transported material brought from higher portions of 

the pediment in the infrequent floods. . The major streams are 

slightly incised and in neighboring localities have begun the formation of a new pediment. Here, however, the streams wander more 

or less at will over the plain. Inspection of artificial excavations 

near by shows that in places the soil is only 2 to 3 inches thick over 

the granite, and residual soil is almost indistinguishable from transported soil. Both types of soil are dark and have a visible content 

of vegetable matter. These characteristics are evidence of the retention of moisture throughout a large part of the year, and in consequence there is a good growth of bushy plants and of perennial 

grass. In the spring the ground is covered with alfileria.

The character of the soil has an effect on two processes, chemical 

weathering of rocks and wind work. The granite underlying flat 

surfaces, as seen in numerous excavations near by, is decomposed to 

depths -of 10 to 20 feet. The ferromagnesian minerals are almost 

wholly destroyed, and the feldspars have become opaque and 

kaolinized. The soil moisture and the ground water circulating in 

the cracks of the granite are apparently effective in decomposing 

the rock. Chemical weathering is much less pronounced in the 

residual hills and masses of boulders, but these places have little 

soil, and because of their elevation the ground water drains away 

from them. The projecting rocks are therefore eroded largely by 

mechanical weathering that is, granular disintegration and exfoliation. The dark humus-bearing soil is compact and not easily
10 CONTRIBUTIONS TO GEOGRAPHY Of UNITED' STATES,, 1923-1&24.

disturbed by wind; moreover, the numerous shrubs and the partial 

sod formed by clumps of perennial grass inhibit wind scour. In 

March, the month of most wind, the alfileria generally forms a 

blanket over the surface. The spring of 1921 was unusually dry, 

and the alfileria merely started to grow and then died. Yet during 

several days of high wind the writer saw no dust rise or sand move 

on the pediment north of Oracle, though great clouds of dust were 

raised from the sandy beds of Big Wash and San Pedro River.

The carving of a monolith into a form with overhanging sides, 

as in the example illustrated in Plate V, A, must be due to special 

causes that can not be closely defined, yet wind work, as shown in 

the preceding paragraph, is definitely eliminated. The rock doubtless originates as a block bounded by joint planes along which 

weathering proceeds, and it remains as a unit after the surrounding 

joint blocks have been removed. The formation of the concave 

sides from joint planes that were originally vertical or slightly inclined is related to the formation of the smooth and iron-stained 

crust that caps the rock. This crust protects the upper part of the 

rock from granular disintegration under changes of temperature, 

a process that seems to have played a large part in the formation of 

the light-colored surfaces of the sides with their projecting mineral 

grains. It seems likely also that the surrounding moisture-retentive 

and humus-bearing soil promotes chemical action at the base of the 

rock and tends to undermine the walls. The debris resulting from 

this combined mechanical and chemical erosion is periodically removed by drip from the rock during rains and by the ephemeral 

streams of the surrounding pediment.

BOCKS OF THE PEDESTAL TYPE IN CENTRAL NEW

MEXICO.

Near the mouth of Tijeras Canyon, in the Sandia Mountains, 

about 10 miles east of Albuquerque, N. Mex., there are numerous 

isolated masses of boulders, rocking stones, pillars, and monoliths. 

Some of them resemble the pedestal rocks described above, though 

none of them are particularly striking in appearance.

The climate is arid, with a relatively strong concentration of rain 

in the summer. There are winter frosts, but not much snow. No 

rainfall records for stations near by are available. The altitude is 

about 6,000 feet, and in central New Mexico localities at that altitude 

usually have an annual precipitation of 10 to 12 inches.

Tijeras Canyon consists of an older valley trenched by a narrower steep-walled younger valley which is partly filled with alluvium. 16 

Near the mouth of the canyon the pediment that skirts the western

i« Bryan, Kirk, Geology of the vicinity of Albuquerque, N. Mex.: New Mexico Univ. Bull. 51, GeoL 

ser., vol. 3, No. 1, pp. 7-8, fig. 2,1909.
PEDESTAL HOCKS IN THE ARID SOUTHWEST. 11

front of the Sandia Mountains is continuous with a wide bench that 

forms a part of the older valley.17 Boulders mark this old erosion 

surface (PL V, B). Some are mere clusters of rocks; others are 

nearly of the perfect pedestal form. They are produced by granular 

disintegration and exfoliation from the underlying and locally coarsegrained biotite granite. That wind scour is not an agent in their 

formation is established by the lack of wind-blown material and the 

presence of perennial grass, which is plainly visible in the photograph, although it has been closely cropped by goats belonging to 

the inhabitants of the near-by village of Carnuel. The local coarse 

soil composed of granite debris has particles too large to be moved 

by the wind and is also held in place by grass roots. The surfaces 

of the rocks show no polish but, on the contrary, have a rough texture due to the projecting of individual mineral grains, similar to 

the texture of the surfaces of the sides of the rocks at Oracle, Ariz. 

This surface is a typical result of the mechanical disintegration of 

granular rocks under changes of temperature, and to this process 

together with exfoliation is due the form of these rocks.

CONCLUSION.

The pedestal rocks described in this paper are of various types 

and cover a wide range of climatic conditions. Not all types of 

pedestal rocks are included, and it is possible that by chance those 

described are unusual. The examples cited, however, are to be 

attributed to the work of rain, of mechanical disruption, and of 

chemical weathering, and none of them would serve in any sense as 

proof of wind work. It would seem, therefore, that caution should 

be exercised in using the presence of pedestal rocks as a criterion 

of wind erosion.

" Ellis, R. W., Geology of the Sandia Mountains: New Mexico Univ. Bull. 108, Geol. ser., vol. 3, No. 4, p. 

14, pi. 1,1922. In this paper part of the pediment is mapped as "old base-level."

THE PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS.

By WILLIAM C. AIDEN.

INTRODUCTION.

The area described in this paper lies mainly in central Massachusetts and comprises about two-thirds of the plateau extending from 

the eastern part of the Connecticut Valley on the west to the lowlands of Middlesex County on the east (fig. 1). The area is about

FIQDBE 1. Map showing location of the Holyoke, Ware, and Quinslgamond quadrangles,

central Massachusetts.

52 miles in exstent from east to west and 35 miles from north to south 

and includes approximately 1,835 square miles. It lies between 

parallels 42° N. and 42° 30' N. and meridians 71° 30' W. and 72° 

30' W. and thus includes on the south a strip of northern Rhode 

Island about half a mile to a mile wide and a strip of northeastern 

Connecticut about 2 to 2£ miles wide.

In the years 1885-1887 a topographic survey of the Belchertown, 

Barre, Worcester, Marlboro, Palmer, Brookfield, Webster, and Blackstone 15-minute quadrangles was made by the United States Geologi92818° 25 2 13
14 COJSTTEIBUT10NS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

cal Survey, and maps of these quadrangles were published on a scale 

of 1:62,500, or approximately 1 mile to the inch, with a 20-foot contour interval. In 1908 these maps were combined into two covering 

the same area on a scale of 1:125,000, or approximately 2 miles to the 

inch, with a contour interval of 40 feet. The two 30-minute quadrangles thus mapped were designated the Ware and Quinsigamond 

quadrangles. These maps are combined .in the present paper (PL 

VI, in pocket) to show the physical features.1

The writer's examination of the surficial geology of this area was 

designed to be supplementary to the work of Prof. B. K. Emerson, 

who had for a long time been studying the deeper-seated hard-rock 

formations. The material included in the present paper was gathered in the summers of 1906 and 1907 and was originally prepared 

for publication with the results of Professor Emerson's studies in 

folios of the Geologic Atlas of the United States and was submitted, 

for examination and criticism, not only to Professor Emerson but 

to Profs. T. C. Chamberlin, W. O. Crosby, and J. H. Perry and later 

revised. To these gentlemen the writer wishes to express his appreciation for numerous suggestions. Professor Emerson had previously published the results of his own studies of the western part of 

this area and of the Holyoke quadrangle, which lies immediately 

west of the Ware quadrangle.2 To these publications and to personal 

conference with Professor Emerson the writer is much indebted. 

Considerable material has also been obtained from publications of 

other authors, as cited elsewhere in the text, particularly the " Physical geography of Worcester, Mass.," by J. H. Perry.

Professor Emerson's " Geology of Massachusetts and Ehode Island " 3 includes a brief description of the glacial and lacustrine phenomena of the Ware and Quinsigamond quadrangles and adjacent 

areas. Some material was prepared by the present writer during the 

World War for incorporation in a description of the country around 

Camp Devens, by W. W. Atwood, printed on the back of the Camp 

Devens topographic map, which covers parts of the Worcester, Marlboro, and adjacent quadrangles.

It is realized that publication so long after the time of the original 

studies, without reexamination of the field, incurs the risk of some 

anachronisms of description. It is hoped, however, that these will 

be found not to be serious. The elements of human history, such as

t Such later features as the Wachusett Reservoir and changes due to its construction, 

enlarged towns, and the newer roads and electric railways are not shown on the 

15-minute maps, but they show considerably more topographic detail than, the Ware and 

Quinsigamond maps and are suitable for class and field use. All these maps are for sale 

by the Director of the United States Geological Survey, Washington, D. C., at 10 cents 

each, or 50 for $3.

2 Emerson, B. K., Geology of old Hampshire County, Mass.: U. S. Geol. Survey Mon. 29, 

1898; U. S. Geol. Survey Geol. Atlas, Holyoke folio (No. 50), 1898.

 U. S. Geol. Survey Bull. 597, 1917.
PHYSICAL FEATURES OF CENTfiAL MASSACHUSETTS. 15

the settlement of the region by the whites and its commercial development, are not treated in this paper. For these subjects reference 

should be made to other sources, among which may be noted a pamphlet on the geography of Worcester, by Robert M. Brown, formerly 

of the State Normal School, who treats in an elementary form 

adapted to class use certain of the phenomena described in the 

present paper.

ORIGIN AND HISTORY OF THE CENTRAL

MASSACHUSETTS UPLAND.

THE CRETACEOUS PENEPLAIN.

An observer standing on any portion of the upland of central 

Massachusetts that affords an extended view is struck at once with 

the remarkable uniformity of the horizon line (PL VIII, A). As 

he gazes in all directions and notes the general correspondence of 

upland and ridge crests, he is impressed with the idea that were the 

valleys filled up to the level of the summits of the ridges the whole 

would constitute a nearly uniform plain sloping gently toward the 

southeast and with but few elevations rising above it. The mineral 

composition and the attitude of the closely crumpled rock formations 

now exposed at the surface in this region (PL IX, B) are for the 

most part of the types that are generally associated with the internal 

structure of mountain folds and are developed only at great depths 

below the surface of the earth, and it is therefore evident that the 

exposure of these formations must be due to the removal of great 

thicknesses of overlying rock. In consequence New England has 

been called a " worn-down mountain region." 4 The removal of this 

material was accomplished principally by the ordinary processes of 

rock weathering or decay and stream erosion, such as are going on 

about us every day. The upland represents an ancient land surface 

developed through long-continued wearing down, which reduced 

most of the preexisting land forms to a plain gently sloping to the 

sea. Such a surface is called a peneplain that is, almost a plain. 

Valleys were broadened and mountains, hills, and ridges were cut 

away until but few portions of the former elevated tracts remained. 

The most notable of the remnants of higher levels still persisting in 

the area under consideration are Wachusett Mountain (PL VIII, B) , 

Little Wachusett, and Asnebumskit Hill. Farther northwest, in 

New Hampshire, stands Mount Monadnock, the typical representative 

of such topographic features, to which its name (monadnock) has 

been given.5 The wearing away of the ancient mountain ranges

* Davls, W. M., The physical geography of southern New England, In The Physiography 

of the United States: Nat. Geog. Soc. Mon., p. 280, 1896.

B Davis>, W. M., The improvement of geographical teaching: Nat. Geog. Mag., vol. 5, 

p. 70, 1893.
16 ' CONTRIBUTIONS TO GEOGRAPHY OP UNITED STATES, 1923-1924.

required an exceedingly long time many thousands or millions of 

years. An account of the formation and destruction of these mountains of long ago is not attempted in the present paper, nor are the 

dim vistas of yet remoter ages penetrated. The description begins 

at the time when the mountains had gone and the peneplain had been 

developed.

The detritus from the long-continued erosion of the land was 

swept by the streams into the bordering seas, forming sedimentary 

strata. The fossils now found embedded in these strata are forms 

that lived in the Cretaceous period, and the ancient land surface 

is therefore known as the Cretaceous peneplain. To visualize this 

ancient peneplain it is necessary, as indicated above, to imagine the 

depressions filled up to the level of the intervening ridge crests, for 

the peneplain is now largely dissected by valleys ranging'in depth 

from 100 to several hundred feet. Moreover, most of the valleys 

give evidence of having been partly refilled since they were cut. As 

such dissection of a worn-down land surface is accomplished only 

in consequence of uplift sufficient to give to the sluggish streams the 

renewed energy resulting from increased fall, it is concluded that 

the peneplain has been raised to its present position since its development. As shown in Figure 2, most of the higher portions of 

this peneplain are in the north-central part of the area, northeast 

of Worcester and north of the main line of the Boston & Albany 

Railroad. Here great tracts stand from 900 to 1,300 feet above sea 

level. Smaller tracts at nearly the same general altitude extend the 

high belt southward from Warren into the eastern part of Hampden 

County and Connecticut. From this axial zone the general upland 

slopes from 900 to 500 feet above sea level in a southeasterly direction toward Rhode Island, and to about 400 to 600 feet in an easterly direction, to the borders of the lower Nashua, Assabet, and 

Blackstone river basins in eastern Worcester County. The high 

portions (900 to 1,300 feet above sea level) are also extensively preserved north of Belchertown and west of Middle Branch of Swift 

River. Prior to the uplift in late Cretaceous time the peneplain was 

probably continuous throughout this region and extended westward 

across what it now the Connecticut Valley lowland.

It has been pointed out by Barrell 6 that the surface descends 

from the higher altitudes in southern New England toward the coast 

not by a simple regular slope but by a series of steps. Barrell has 

suggested that after dissection of the region had reached an advanced 

stage the land was lowered, in part below sea level, so that the interstream ridges became peninsulas, islands, and reefs, which were then 

in turn partly worn away by marine wave action. Repeated wave

6 Barrell, Joseph, The piedmont terraces of the northern Appalachians (edited hy H. H. 

Robinson) : Am. Jour. Sci., 4th sen, vol. 49, .pp. 227 et seq., 1920.
IT. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE VIII

A. DISSECTED PLATEAU OF CENTRAL MASSACHUSETTS.

B. WACHUSETT MOUNTAIN, A MONADNOCK RISING ABOVE THE PLATEAU OF 

CENTRAL MASSACHUSETTS.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE IX

A. GLACIAL TILL, A HILL OF UNSORTKU GLACIAL DIIIFT MOUTH OF CLINTON,

MASS.

Photograph by \V. W. Atwood.

li. DANA DIORITE ("RIBBON GNEISS") 1 MILE SOUTHEAST OF GIBBS CROSSING,

WARE, MASS.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 17

cutting following each of several successive uplifts of the region 

resulted in the development of a series of great steps or dissected

terraces dropping from the highest levels toward the coast line on 

the south and east of New England. These steps are said to be 

recognizable in broad cross-country views at the different altitudes.
18 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

One of them is supposed to embrace the higher parts of the area 

under consideration and appears to correspond to what has been 

described above as the Cretaceous peneplain. The drop to the next 

lower step is in general to be found along 1 zone extending from 

north to south a few miles east of Wachusett Mountain and Asnebumskit Hill, curving to the west near the latitude of Worcester, 

turning again southward in the region of Brookfield, and extending 

thence through or near eastern Hampden County into Connecticut. 

Barrell's hypothesis may be open to question but is outside the general scope of this paper and will not be further discussed here.

EARLY TERTIARY STREAMS AND VALLEYS.

In the next succeeding geologic period the Tertiary several 

streams either crossed or headed in this area, and it also appears 

that marked changes in the drainage system of the area occurred 

during Tertiary time. The changes were a consequence of differential erosion that is, the more rapid wearing away of the softer 

than the harder parts of the rock formations that underlay the 

Cretaceous peneplain. This is shown by the fact that some streams 

follow courses that are otherwise unexplainable that is, they 

flow in directions transverse to the general slope of the country 

rather than directly down the slope. It is shown also by the existence of capacious valleys which were clearly not excavated by the 

streams that now occupy them and by the occurrence of deep notches 

or wind gaps (cols) cut in the rock divides and not now occupied 

by streams. It is not possible to interpret the development of all 

such features of the landscape, and only some of the more significant 

and most readily explained will be discussed here.

Crosby's studies! of the region led him to believe that a plain 

formed by a mantle of Cretaceous sediments originally extended at 

least as far inland as the line of the Nashua Valley, and that after 

this plain of deposition was uplifted with the eroded peneplain, early 

in Tertiary time, the rivers found their way seaward across it in 

channels that bore no relation to the structure or composition of the 

older rocks beneath, and on the removal of the Cretaceous sediments 

by erosion the streams continued to flow in these channels, which 

were thus superimposed upon that part of the eroded peneplain that 

had been buried that is, the stream courses then extended indiscriminately across belts of hard and soft rock alike. The original extent 

of the Cretaceous sediments is not fully known, but there can be 

little doubt that the development of the Tertiary drainage lines, 

whether on the uplifted plain of deposition or directly on the older 

worn-down plain, depended wholly on the slope and configuration 

of the newly elevated surface, regardless of the structure and vary-
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 19

ing degrees of hardness of-the rock formations beneath, and that the 

branching of the streams was much nearer the dendritic or treelike 

type than it is now.

Normally streams that have begun to cut on bedrock wear away 

soft rocks more readily than harder rocks, so that no matter where 

they begin to flow they have a tendency to readjust their courses and 

eventually, if nothing prevents, to follow more or less closely the belts 

of softer rocks. As a matter of fact, however, many different things 

generally happen to prevent perfect readjustment. During the 

process of readjustment in this area there were probably many 

changes in the courses, of the streams. Several of the wind gaps in 

the rock ridges are regarded as portions of the courses' of the earlier 

Tertiary streams that were later abandoned. The supposed courses 

of the early Tertiary drainage lines of the region about Worcester 

and adjacent areas are shown in Figure 3. Those forming parts 

of the ancestral Nashua River system were suggested by Crosby 7 as 

a result of his studies in connection with the building of the dams for 

the Wachusett Reservoir.

The large gap in the east rim of the Nashua Valley near Ayer, 

4 miles north of the village of Harvard (just north of the area 

shown on PI. VI), was probably occupied by one of the main streams, 

which flowed thence northeastward along the line of Stony Brook 

valley to Merrimack River west of Lowell. The principal tributaries of this stream converging at the gap at Ayer were Nissitissit 

River, flowing southward in what is now Nashua Valley; Squannacook River, from the northwest; and possibly North Nashua 

River, flowing eastward from North Leominster past Shirley to 

Ayer, and a small stream, flowing northward in what is now the main 

valley of Nashua River between Lancaster and Ayer.

There are three notches in the east rim of the valley in the vicinity 

of Clinton. (See fig. 3 and PI. VI.) The most northerly is traversed by the New York, New Haven & Hartford Railroad at Bolton 

Station, at an altitude of 384 feet above sea level; a second, 1 mile 

to the southwest, is occupied by that part of Clinton known as " The 

Acre," which has an altitude of 370 feet; and a third was formerly 

traversed by the Boston & Maine Railroad from West Berlin to 

Boylston, about half a mile south of the Wachusett dam. This 

third gap, which is now blocked by the south dike of the Wachusett 

Reservoir, was an important outlet for glacial waters during 

Pleistocene time and may for convenience be designated the south7 Crosby, W. 0., Geology of the Wachusett dam and Wachusett aqueduct tunnel of the 

Metropolitan waterworks In the vicinity of Clinton, Mass.: Tech. Quart., vol. 12, pp. 

68-96, 1899; Geological history of the Nashua Valley during the Tertiary and Quaternary 

periods: Idem, p. 288-334; Structure and composition of the delta plains formed during 

the Clinton stage in the glacial lake of the Nashua Valley : Idem, vol. 16, pp. 240-254, 

1903; vol. 17, pp. 37-75, 1904.
20 CONTBIBUTIONS TO GEOGBAPHY OF UNITED STATES, 1923-1924.

dike outlet. Its altitude was about 360 feet. The first of these gaps 

is about 120 feet in depth, the second 70 to 80 feet, and the third 140

Boylaton x -' MacLbor< 

Center

EXPLANATION

Earlier Tertiary streams Later Tertiary streams Present streams

FIGURE 3. Diagram illustrating stream changes in central Massachusetts. (Principally 

after W. 0. Crosby and J. H. Perry.)

to 160 feet. These gaps are notable in that they do not occur at 

exceptionally weak points in the rock ridge but are cut in the most 

resistant rocks of the region granite, diorite, and quartzite. From
PHYSICAL FEATUEBS OF CENTRAL MASSACHUSETTS. 21

these gaps converging valleys now lead to the valley of North Brook, 

a tributary of the broad ^ssabet River basin, at West Berlin. In 

Tertiary time these passes were in all probability traversed by 

streams heading on the lower east slope of the Wachusett divide. 

It is believed that the broad Nashua Valley in the vicinity of Clinton was not then excavated, so that the streams converging to form 

this system may have been one on the line of the lower North 

Nashua River heading east of the north end of Ballard Hill and 

flowing thence through the gap at Bolton Station; one heading in 

the gap north of Redstone Hill and flowing thence through the sag 

in the ridge on which Clinton is built and through the gap directly 

opposite at " The Acre"; and a stream from the sag in which lie 

the "VVaushaccum Ponds, flowing through the south-dike outlet. 

Possibly at one stage Stillwater River may have followed this lastmentioned course. All these waters are thought to have reached the 

Atlantic Ocean at Boston Harbor by way of either the Merrimack 

or the Charles.

One mile southwest of Boylston Center the rim of Nashua Valley 

is cut by a gap over half a mile wide at the head of Quinsigamond 

Valley, the Muddy Brook gap. The lower parts of the rock bottom 

of this gap are probably not over 400 feet above sea level, and the 

crests on either side rise 200 to 300 feet higher. -This gap is directly 

opposite the bend in the Nashua Valley, so that the eastern and 

western parts of the valley converge toward it. In continuation 

of the valley north of Oakdale is the valley of Stillwater River, and 

the normal course of that stream at an early stage would have been 

by way of Muddy Brook gap down Quinsigamond Valley, and a 

branch from Sterling Junction would have traversed the gap west 

of French Hill now filled with glacial drift.

The course of the main tributaries of Quinapoxet River from the 

south slope of Wachusett Mountain suggests an early channel 

through the gap 820 feet above sea level at the head of Tatnuck 

Brook and the gap 760 feet above sea level south of Chaffin Pond 

and thence to the ancient' river valley at Worcester. Possibly also 

Stillwater River once went southward to the same valley by way 

of the gap north of Summit Station. If these inferences are'correct 

these streams must have been diverted to the stream in Quinsigamond 

Valley through the process of capture, by which the head of one 

stream cuts back into another stream's valley. As a rule, the pirate 

stream has a steeper grade or a greater volume or is working on 

softer rock and is cutting more rapidly than the stream whose waters 

it captures. That a considerable stream once flowed southward 

through Quinsigamond Valley is evident from the capacious dimensions of the valley, which is now largely blocked with drift and 

wholly out of proportion to the streamlets that occupy it.
22 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

In the Blackstone Valley, farther south, the constricted rock 

channel from Millville to the eastern part of Blackstone is in 

striking contrast with the broad drift-filled sag south of Ironstone. 

This sag, which is a mile or more in width, leads southward directly 

in line with the broad valley of the Blackstone above the bend at 

Ironstone, and it might be inferred that the heavy filling of drift 

south of Ironstone diverted the river eastward. Further inspection, 

however, shows a series of rock ledges at close intervals across the 

valley near the head of the Ironstone Keservoir, at altitudes of 260 

to 320 feet, arid more or less drift filling occurs in the Blackstone 

Valley southeastward as far as Woonsocket. From these facts it 

appears that the Blackstone was diverted to its present course below 

Ironstone prior to the advent of the great ice sheet. Although the 

ancient valley has not been traced southward to the sea, it seems very 

probable that the original course of the stream in early Tertiary 

time was along the broad sag south of Ironstone. No well-marked 

terraces cut in rock occur in the Blackstone and Quinsigamond 

valleys, but at a few places there are evidences that a broadening of 

the rock bottom took place at altitudes corresponding with the 

gradient of an ancient valley floor from the gap at the head of 

Quinsigamond Valley southwest of Boylston Center to the sag 

south of Ironstone. These evidences are found in the exposures of 

bedrock beneath a slight covering of gravel of the Pleistocene terraces. The most notable of these rock benches are in the angles 

between the converging Mumford, Blackstone, and West rivers, 

northeast of Uxbridge.

Another large Tertiary river was that which excavated the capacious valley leading southward from Worcester to Lake Chaubunagungamaug, east of Webster. Northward from a divide 2 miles 

northeast of North Oxford the valley is now drained by Blackstone 

River through the narrow gap cut in the rock at Quinsigamond village. South of the divide, which is only an insignificant ridge of 

drift, the drainage goes to French River, which leaves the main valley at Webster for a much narrower channel. For more than 20' 

miles the broad valley bottom ranges in width from three-fourths of 

a mile' to 2 miles, and the side slopes rise to heights of 200 to 400 

feet above the present floor within distances of less than a mile. The 

filling of drift beneath the present bottom is reported to be in many 

places 60 to 90 feet thick. The valley is continuous from north to 

south and is wholly out of proportion to the small streams that now 

occupy it. It was clearly at one time a large drainage channel, and 

Perry 8 has suggested the name "Auburn River" as a convenient 

designation of the Tertiary stream that accomplished its excavation.

8 Perry, J. H., The physical geography of Worcester, Mass., p. 35, Worcester Nat. Hist, 

goc., 1898,
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 23

It is possible that at an early stage this stream received the drainage from the south slopes of Wachusett Mountain through cols north 

and northwest of Worcester by the streams that are now tributary 

to the Quinapoxet. Like Blackstone and Nashua rivers, the ancient 

"Auburn River " was apparently diverted in Tertiary time, before the 

excavation of the valley was fully accomplished. This is shown by 

the fact that near the railroad west of East Thompson, Conn., If 

miles south of Lake Chaubunagungamaug, rock crops out at snort intervals across the valley floor at latitudes of 480 to 560 feet above the 

sea, and as.far north as Worcester, a distance of 19 miles, the rock 

bottom of the ancient valley has been encountered in drilling at altitudes as low as 370 to 400 feet.

 Even though allowance is made for the possible changes in the relative altitudes of the several parts of the region, it seems clear that 

notable stream adjustments must have been accomplished prior to 

the advent of the Pleistocene glaciers. Similar changes doubtless 

occurred in the western part of the area, but they are not discussed 

in the present paper.

The preglacial course of Swift River is shown by Emerson 9 to 

have led southward past Palmer and Monson along the valley traversed by the Central Vermont Railway and into Connecticut through 

the pass near Stateline Pond.

The reconstruction of the early Tertiary drainage systems above 

outlined is from the nature of the case entirely hypothetical, and it 

may not point out the exact changes that occurred in the process of 

stream adjustment; its value lies rather in showing the nature of 

the process by which the streams came to occupy their present channels. If the correctness of the interpretations is assumed, however, 

we have for early Tertiary time in that part of the then newly elevated peneplain which is under consideration an arrangement of 

streams such as is shown in Figure 3.

LATER TERTIARY STREAM ADJUSTMENTS.

Nashua River occupies a deep and well-defined valley incised in 

the Cretaceous peneplain and carved out of argillaceous slate or 

phyllite between the great ridge of granitic and gneissic rocks on the 

west and a distinct ridge of granite and schist on the east. This 

phyllite was originally a bed of soft black coaly clay. It was compressed by the weight of overlying rocks and later squeezed and 

crumpled by mountain-making forces. This changed, some of the 

minerals and caused the flakes of mica and graphite and other minerals to lie flat. The rock now stands on edge and splits very readily

o Emerson, B. K., U. S. Qeol. Survey MOD. 29, pi. 11, 1898.
24 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

into thin layers, some of it yielding good roofing slate. Such being 

its character and position, it is easily worn away by running water. 

The stream, as shown by the map, does not follow a normal course 

dependent upon the slope of the ancient peneplain eastward to the 

sea but instead flows transverse to this general slope and parallel 

to the strike of the upturned rock formations north-northeastward 

to its confluence with the Merrimack at Nashua, -N. H. Its course 

is in general adjusted to the geologic structure of the rock formations over which it flows.

The records of test borings to determine the location of the north 

dike of Wachusett Reservoir, as shown by Crosby,10 indicated that 

beneath the pitted sand plains which occupy the broad valley west 

and southwest of Clinton is a buried rock gorge, evidently an ancient 

channel of Nashua River. Crosby writes:

We find that the western slope of Burdette Hill, which is but thinly covered 

by till, extends for fully 1,000 feet beneath the plain of modified drift with the 

normal height of 380 feet, to a well-defined north-south depression with an 

average elevation of only about 200 feet, sloping both ways from a distinct 

water parting. A definite ridge of schist, which is covered at the highest point 

by 100 feet of modified drift, separates this depression, from the deeper one 

beyond. Along the west side of the ridge * * * is an uneven bedrock 

terrace several "hundred feet wide, crossed by several spurs from the ridge and 

with an approximate elevation of 190 to 210 feet. Over this terrace, with 

120 to 130 feet of drift intervening, lies Coachlace Pond; and immediately 

beyond and1 along a line parallel with the pond and the ridge the bedrock 

surface falls off abruptly about 100 feet more, and the drift reaches the 

astonishing thickness of 250 to nearly 300 feet.

The lowest elevation [above sea level] of the bedrock surface determined 

by the borings is 96.5 feet on the center line of the main cut-off, nearly 200 

feet west of Coachlace Pond. Since it is improbable that this boring, which 

has a depth of 272.5 feet, is located over the very lowest point in this profile 

of the valley, and especially since it failed to reach bedrock, we may fairly 

assume that the minimum elevation of the bottom of the gorge on this line is at 

least as low as 95 feet, and probably as low as 90 feet.

That Nashua River in the narrow gorge at Clinton is out of. the 

course it followed prior to the deposition of the glacial drift is 

indicated by the topographic relations and by the fact that it flows 

over a granite ledge at the Chestnut Street Bridge, although at the 

site of the Wachusett Dam, half a mile farther upstream, borings 

show that the bottom of the narrow gorge lies 60 to 70 feet below the 

present bed of the sfream. Crosby found that the buried gorge 

beneath the dam had been cut by a southward-flowing stream along 

the contact of the westward-dipping granite and phyllite, with a 

precipitous and even overhanging wall of granite on the west. This 

gorge was doubtless tributary to the channel now buried beneath 

Coachlace Pond.

10 Tech. Quart., vol. 12, pp. 294-295, 1899.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 25

The presence of the deeply buried channel west of Clinton, with its 

bottom less than 100 feet above sea level, at so great a distance from 

the sea nearly 80 miles measured along the present courses of the 

Nashua and the Merrimack naturally indicates a further extension 

of the ancient gorge, even though there are no borings in the Nashua 

Valley north of Clinton by which its location could be determined. 

Data obtained by Crosby from. W. F. Sullivan, of the Lowell waterworks, showed that although the Merrimack at present flows over 

rock ledges at the lower dam at Lowell at an altitude of 92 feet above 

the sea and rock is exposed on either side of the channel or reached 

at shallow depths for some distance through the city below the dam, 

yet borings near the river above the dam show the presence of a 

buried channel with its bottom near sea level. Borings and other 

data indicated the probable continuation of the channel about either 

the north or the south side of the city of Lowell. Crosby's further 

studies convinced him that the preglacial course of the Merrimack 

below Lowell led southeastward to Boston Harbor.

Between 4 and 5 miles north of the village of Harvard, near Ayer, 

the rock ridge east of the Nashua Valley is breached by the gap already mentioned. This gap, which is at the point where the valley 

is widest, is about 1 mile in width. Beyond the gap the rock ridge 

extends northward, though it is not so high or continuous as it is 

south of the gap. Not only has the present lower Nashua Eiver a 

retrograde course with reference to the Merrimack that is, it flows 

in a general opposite direction but the principal tributaries of the 

Nashua are also retrograde with reference to that stream, and, as 

pointed out by Crosby, there is a very decided convergence of the 

members of the Nashua River system toward this break in the eastern 

rim of the valley near Ayer. He states that this break is particularly 

notable, inasmuch as the present water parting between Nashua 

River and Stony Brook, which heads a short distance east of this 

break and enters the Merrimack at North Chelmsford, is almost imperceptible and apparently composed wholly of drift. Moreover, 

through the entire distance from its source east of Nashua River at 

Ayer to the Merrimack at North Chelmsford, Stony Brook traverses 

a broad and unobstructed valley entirely out of proportion to itself. 

Except at on© place within a few rods of the mouth of the brook 

at North Chelmsford, Crosby found the valley virtually devoid of 

rock outcrops and apparently containing a considerable thickness of 

drift. " The valley," he writes, " is not only broad, but the breadth 

is remarkably uniform, so that it is practically a valley without a 

head, a mere strait some dozen miles in length between the Nashua 

and Merrimack valleys, and not at all the type of valley we should 

expect if it were due to the unaided activity of Stony Brook." His 

examination developed no facts inconsistent with the view that the
26 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1&24.

Stony Brook valley, except for a short distance where obstructed 

by rock at North Chelmsford, afforded an outlet for the drainage 

of the Nashua Valley in preglacial time, and this view was further 

supported by the fact that the present valley of Nashua River north 

of Ayer is relatively narow and much obstructed by ledges. The reopening qf the Stony Brook outlet for the Nashua River drainage 

would make the. courses of all the principal tributaries direct that 

is, they would all converge to the trunk stream in normal fashion 

with the exception of the North Nashua, but this large branch would 

still have a retrograde course. Above North Leominster its course 

is essentially direct, but below that point for nearly 9 miles, to its 

confluence with the main stream at Lancaster, it is notably indirect 

that is, it flows southeast to join the main stream, which is flowing 

northeast. At several places in the lower course the North Nashua 

flows over rock ledges. One of these is at the north end of Ballard 

Hill, and Crosby concluded that the earlier course was probably more 

directly eastward from North Leominster, past Shirley, to the outlet 

at Ayer.

If these interpretations! are correct, the arrangement of the drainage lines of the Worcester region and adjacent areas immediately 

prior to the Pleistocene glaciation was not only somewhat different 

from the present arrangement, but even more notable readjustments 

had taken place earlier, during the Tertiary cycle of erosion. The 

changes in deployment of the streams shown in Figure 3 were probably accomplished through the process of stream capture (p. 21). 

The most notable captures were those made by Nashua River. The 

rate of cutting down the gap at Ayer through the granite ridge east 

of the valley controlled to a certain extent the work of the tributaries 

above the gap. The Tertiary course of this stream, its consequent 

steep fall, and the large drainage basin above this obstruction gave 

it considerable advantage over the other streams of the area, so that 

the gap at Ayer was deepened more rapidly than those at other 

points. West of the granite lies a broad belt of phyllite, one of the 

most easily erodible of the rock formations of the region. The character of this rock gave to those tributaries that were working along 

its strike that is, parallel to its splitting planes great advantage 

over all the others. Thus the headwaters of the small stream that 

was flowing northeastward from Lancaster cut back rapidly along 

the strike of the, phyllite and diverted to itself, one after another, 

each of the streams that crossed this belt of phyllite. The first to 

be diverted was the stream which was engaged in cutting the gap at 

Bolton Station. This captive, if it had not already done so, in turn 

cut back and diverted the waters of Wekepeke. Brook and North 

Nashua River to their present courses. Next the streams cutting the 

gap at " The Acre " and the south-dike outlet fell victims to the ag-
PHYSICAL FEATUBES OF "01NTBAL MASSACHUSETTS. 27

gressive Nashua. The divide which set off the river in Quinsiganiond 

Valley was then attacked and speedily cut away, and at one stroke 

the whole Stillwater-Quinapoxet system was diverted to the Nashua. 

It is probable that by this time Stillwater Eiver had captured the 

components of the Quinapoxet above Oakdale, even if they originally 

flowed through the cols north of Worcester. That part of the 

Nashua Kiver system within the Quinsigamond quadrangle thus assumed approximately its present arrangement and continued the 

excavation of the capacious valley, whose full dimensions would be 

revealed were the filling of drift removed. In the vicinity of Clinton 

the Nashua, excavated the buried channel described by Crosby, as 

shown by the borings for the north dike of Wachusett Eeservoir. At 

the same time tributaries were cutting the gorge now traversed 

by the Nashua at 'Clinton, one working at the north and one at the 

south.

The Blackstone system was not only beheaded in the manner 

described, but the stream was also diverted from the broad valley 

south of Ironstone to the present narrow gorge through Blackstone 

by a tributary at Woonsocket. The main valley was still further 

deepened after this diversion, and the gap at Quinsigamond was cut 

down nearly to its present depth.

The ancient "Auburn Eiver " was diverted from the broad valley 

in which lies Lake Chaubunagungamaug to the present course at 

Webster by French Eiver, a tributary of the Quinebaug, and the valley was further deepened north of Webster. Similar changes on 

streams farther west doubtless occurred as Connecticut Eiver deepened .and broadened its valley in the Triassic sandstones. At the 

same time minor streams, brooks, and rivulets throughout the region 

were busily engaged in gullying slopes, and dissecting intervalley 

tracts and in removing the products of rock disintegration.

RELATIONS OF THE TOPOGRAPHY TO THE BOCK FORMATIONS.

Emerson 11 has given a brief summary of the relations of the 

present topography to the rock formations, which contains the fol3 lowing paragraph:

At the completion of this [Cretaceous] epoch of erosion the surface of the 

State was a nearly continuous plain, sloping southward and eastward, of which 

the present broad, flat uplands are remnants. This plain was then raised as 

a whole, without folding but by broad warping and tilting, so that in the 

northwestern part of the State it stood about 2,000 feet above the sea. As a 

result of this uplift the streams, which ran southward and eastward across the 

plain, cut deep trenches in the upland. In the soft sandstones of the Connecticut Valley and the soluble limestones of the Housatonic Valley these 

trenches were widened into broad, flat-bottomed valleys, the beginnings of new,

11 Emerson, B. K., Geology of Massachusetts and Rhode Island: U. S. Geol. Survey Bull. 

597, pp. 15-17, 1917.
28 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

transient peneplains, whose elevation was determined not oy sea level.but by 

obstructions farther downstream. Thus erosion has marked out the broad 

topographic divisions of the State, which are also the broad geologic divisions.

Of the six topographic divisions which he recognizes the third, 

comprising Ihe lowlands of the Connecticut Valley, mostly less than 

300 feet above sea level, extends but a few miles into the area described in the present paper and ends at the west foot of the Wilbraham Mountains and the abrupt marginal slope of the upland 

farther north (fig. 2). The fourth and fifth divisions (in order from 

west to east) cover the greater part of this area. These divisions are 

described by Emerson as follows:

Third. The Devonian-Triassic valley of the Connecticut, in which there are 

sharp trap ranges topographically much like Monument Mountain, in the 

Housatonic Valley. Great faults along the scarps on both sides of the valley 

have lowered and thus preserved the sandstones in which the valley has been 

cut to form a younger incipient peneplain.

Fourth. The central upland, or Worcester County plateau, made up of 

alternate broad bands of Carboniferous granite and narrower bands of folded 

schists, repeating in part the structure and lithology of the western upland. 

The northern part of the westernmost range of granite is rather resistant 

and forms monadnocks like Mount Grace, but its southern part has been 

deeply eroded in the Wilbraham Valley. The granite belt next east is made up 

of less resistant rock and forms the Monson Valley and the broad, relatively 

low strip that stretches from Orange to Palmer. The third granite belt is more 

resistant again and forms such monadnocks as Wachusett and Asnebumskit. 

Just east of it the weaker Worcester phyllite is worn down in the low Nashua 

Valley.

Fifth. The bordering slope that descends gradually eastward and southeastward from the irregular but fairly definite escarpment bounding the central 

upland. The descent is by no means uniform, and the general surface, if restored by filling the valleys to the height of the hilltops, would be not at all 

smooth and would not have a regular and gentle slope from the central upland 

to the coast. Southeastern Worcester County and northwestern Rhode Island 

are in large part upland of pre-Cambrian rocks, which, though much lower 

than the central upland, stands distinctly above the country northeast and 

southeast of it. Northeastern Massachusetts, north of the forty-second parallel, 

is crossed by several belts of hilly country which have a general northeast-southwest trend but which converge, in a way, on the rugged upland just mentioned 

and which separate broad tracts of lowland that are, to some extent, the valleys of the main streams of that part of the State. The only one of these hillyo 

belts which can really be called a range extends from Shrewsbury northeastward through Harvard and Westford into Chelmsford and separates the basin 

of Nashua River from that of Assabet and Concord rivers. It follows a belt of 

metamorphosed sedimentary rock which appears to be much more resistant than 

the rocks on either side of it, though they are largely granitic.

East of the latitude of Marlboro and Woonsocket only small hilly 

tracts rise more than 300 feet above sea level (fig. 2). In the intervening tracts are scattered lower hills interspersed with rather broad 

lowlands, mostly sandy. As stated by Emerson,
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 29

There is in a broad way a relation between the topography and the rock 

structure of this part of the State, as the hilly belts are to a large extent underlain by granites and other igneous rocks and the lowlands are more or less 

underlain by sedimentary rocks, but there are so many exceptions that the 

relation is far from being a rule.

QUATERNARY GEOLOGY.

PLEISTOCENE OR GLACIAL EPOCH.

PHENOMENA INDICATIVE OF GLACIATION. 

CLASSES OF DEPOSITS.

Upon the hard rock formations throughout a large part of the 

northern half of the North American continent lies a mantle of unconsolidated materials of various kinds, formed during the Quaternary period. These materials may be grouped into three classes, according to the time and conditions of their deposition. The deposits 

cf two of these classes were formed during the Pleistocene or glacial 

epoch. Of these one class includes the glacial deposits, which were 

either formed directly through the agency of great sheets of ice that 

overspread the region or laid down by waters associated with these 

glaciers and in large part derived from the melting of their ice. 

These deposits are collectively termed the drift. A second class includes such deposits as were formed by various agencies during intervals when the land was free, either wholly or in part, from the dominance of the sheets of ice; these are called interglacial deposits. The 

third class of Quaternary deposits includes all those accumulations 

of material which have been formed in different ways since the latest 

disappearance of the great ice sheets, comprising the postglacial or 

Kecent deposits.

GENERAL CHARACTER OF THE GLACIAL DRIFT.

The drift consists of the materials that were gathered up by the 

glaciers during their advance across the country, transported 

greater or less distances, and finally deposited by being released from 

the grip of the ice (PI. X, A).

In this area good exposures of the; glacial drift are numerous and 

easy of access, being afforded by temporary excavations, cuts for 

roads and railways, and erosional sections where streams are cutting 

the valley slopes. One of the best exposures in the vicinity of Worcester is at the brick-clay pit in the hill east of Plantation Street. 

Exposures in the valley bottoms consist principally of sorted and 

water-laid sand and gravel; those on the slopes and uplands that 

form the greater part of the area are made up of unsorted drift, consisting generally of a matrix of drab or dark ashen-gray clay or 

sandy clay in which are embedded stones of various sizes, shapes, 

and kinds. The finer material constituting the matrix is not a re92818° 25 3
30 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

siduum from the disintegration of the underlying hard-rock formations through weathering, though in some places a small percentage 

of such residual material may be recognized. It is for the most part 

coarse rock flour, the commingled products of the abrasion of the 

several older rock formations of the region. The stones embedded 

in the matrix range in size from small pebbles to boulders weighing 

several tons. Most of the rock fragments in the body of the drift 

are less than a foot in diameter, but boulders 2 or 3 feet in diameter 

are of common occurrence. Among the abundant boulders on the 

surface of the drift, and here and there embedded in it, are masses 

of rock with dimensions of 10 to 20 feet. These boulders could not 

be transported by water currents of any ordinary strength, unless 

they were frozen in great masses of ice.

The arrangement of the greater part of the drift is heterogeneous, 

fine and coarse material, clay and boulders being intimately mixed. 

Such unsorted drift is known as till (PI. IX, A). It is in striking 

contrast with the sorted and stratified beds produced by deposition 

in water. Yet from the common occurrence of stratified material in 

the drift it is evident that considerable water must have aided in its 

deposition.

The pebbles and boulders of the unstratified drift, in contrast with 

stones worn by fluvial or lacustrine waters, are partly angular and 

partly rounded, but most are subangular, with numerous flat faces. 

The faces usually show such polishing and parallel scratching as 

would result from their being held firmly in various positions and 

rubbed for a long time and under great pressure over hard and 

gritty surfaces.

At most places in this area the surface of the bedrock also, when 

stripped of its covering, shows well the effects of abrasive, action. 

Instead of the gradation from solid rock to incoherent soil characteristic of regions where the soil is the residuum from the disintegration 

of the underlying rock, there is usually a sharp line, of separation 

between the surface of the bedrock and the overlying drift. Unless 

the upper rock beds are more or less broken up they usually have 

smoothed and polished surfaces, marked by grooves and scratches 

similar to those on the pebbles and boulders in the drift (Pis. X, #, 

and XI). If the rock surface has not been exposed long to recent 

weathering the striations are sharp and distinct. They are usually 

nearly parallel at any given place or cross one another at low angles. 

Where there are slight inequalities in the surface, such as protruding knobs or jutting ledges, the side facing north is smoothed 

and polished, but the opposite side is rougher and more or less unmodified. In small, sharp depressions the north side is rough, but 

the south side is smoothed.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE X

END OF LOWER BLASE DALE GLAC1KII, DISCO ISLAND, GREENLAND. 

Photograph by T. C. Chamberlin.

J3. GLACIATED ROCK SURFACE NEAR LOWER BLASE DALE GLACIEH, DISCO

ISLAND, GREENLAND. .

Photograph by T. C. Chamberlin.
U. S. GEOLOGICAL SURVEY 

GLACIATED ROCK LEDGE AT CLINTON, 
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 31

When the phenomena of the whole region are taken into consideration it becomes apparent that the glaciers depositing the drift

Terminal moraine Direction of ice movement

(Generalized')

FIGURE 4. Map of parts of New England, New York, and New Jersey, showing extent, 

directions of movement, and terminal moraines of the last great ice sheet. (Compiled 

by William C. Alden from observations of many geologists*)

of New England came from centers far to the north, spreading southward and southeastward over the land till they encroached upon 

the waters of the bordering ocean (fig. 4).
32 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924. 

GLACIAL AND INTERGLACIAL STAGES.

The great North American ice sheet had two main centers of 

growth one west of Hudson Bay, the other on the peninsula of 

Labrador (fig. 5), east of the bay. The ice that invaded New England belonged to the Labrador sheet.

FIGURE 5. Map showing area covered by the great ice sheets in North America at their 

maximum extension and the centers of ice accumulation. (Compiled by William C. 

Alden from observations of many geologists.)

So long as the rate of accumulation of the ice exceeded the waste 

by melting and evaporation the ice sheet continued to advance, but 

when a region was reached where the waste equaled the rate of 

advance the margin halted. When the waste exceeded the advance 

the margin was melted back. When the ice became stagnant melting caused the sheet to disintegrate in place. Periodically there were
PHYSICAL FEATURES OP CENTRAL MASSACHUSETTS. 33

great oscillations of the ice front so notable in their extent and in 

their effects as to be designated stages of the Pleistocene epoch. 

During the stages of glaciation the ice advanced far to the south, 

driving plants and animals before it and destroying and burying in 

the drift such as remained. During the stages of deglaciation a 

reversal of these conditions took place. The climate became so 

much milder that the ice was melted, a new soil was developed, and 

plants and animals returned to their former habitats. Study of 

buried soils and organic remains and of the modifications which the 

several drift sheets have undergone as the result of exposure to the 

weather and to stream erosion for different periods of time has led 

to the determination that the Pleistocene epoch comprised a series 

of these glacial and interglacial stages.

The differentiation of the several drift sheets has been most 

clearly made out in the Mississippi Valley. Although there are 

reasons for believing that earlier glaciers spread over New England,, 

it is not certainly known that more than one drift sheet, that of the 

last or Wisconsin stage of glaciation, is represented in central Massachusetts. So far as known to the writer, no deposits that are clearly 

assignable to an interglacial stage have been found in this region. 

Consequently, this discussion treats the glacial phenomena of the 

region as if they were the product of a single ice invasion that of 

the Wisconsin stage.

The phenomenon of glaciation was initiated in the regions at the 

north by climatic conditions that resulted in vast accumulations of 

snow, which at length became perennial, through failure to melt 

. entirely during the summers. As the snow piled up the light flakes 

changed to granules, and these in turn became coherent in a mass of 

porous glacier ice. Under the proper conditions of temperature, 

volume, gravity pressure, and slope, internal movement is initiated 

in such a mass so that the ice spreads from the centers of accumulation. - After reaching sufficient thickness the ice front steadily advanced from the Labrador center over valley, plain, and hill and 

surrounded the mountain slopes until at length the vast sheet of ice 

even overtopped the crests of New England's highest mountains, 

and the Adirondacks, the Green and White mountains, Mount Katahdin, Mount Monadnock, and Wachusett Mountain all disappeared 

beneath it. No peak is known to have risen above the extensive 

plateau of ice thus formed. Figure 4 shows the general directions 

of movement over New England as recorded in the scorings on the 

surface of the rock. Though local deflections resulted from the trend 

of topographic features the sheet of ice as a whole moved slowly 

and irresistibly forward in a southeasterly direction, overriding all 

obstacles until it reached Long Island and the sea.
34 cottTBiBtmoisrs TO GEOGRAPHY OF TOTTED STATES, 1923-1924.

DIRECTIONS OF THE ICE MOVEMENT.

The following observations of striated ledges indicate the directions of the ice movement within the Quinsigamond quadrangle. 

Beginning at the northwest, examination of the summit and slopes 

of Wachusett Mountain shows clearly the effects of glaciation. 

Where the ledges are not bare they are covered with a thin coating 

of gravelly till. On stripping off this coating striated surfaces of 

the rock are revealed.

On Wachusett Mountain a few rods east of the Summit House and near the 

stables striae show the following bearings: Due south, S. 15°-18° B., S. 

20° E., S. 30°-40° E.

In going down the slope along the road striae were noted as follows: South 

side of stables, S, 10°-22° E.; at 1,850 feet, S. 18° E.; about 1,813 feet above 

sea level, S. 10°' E.; at 1,750 feet, S. 15° E.; at 1,700 feet, S. 15° E.; near 

the spring below the bend in the road at 1,556 feet above sea level, S. 25°-30° E.

At 500 paces to the west along the new road from the bend at 1,556 feet, 

striae trend S. 20°-23° W., and a little farther west, S. 17° W.

This divergence is the result of deflection of the basal ice about the west 

slope of the mountain.

About 1£ miles farther south stripping for the new road 40 rods north of 

the corner exposed glaciated ledges with striae trending S. 15°-26° E.

Prince ton Township, road on north slope of Calamint Hill, S. 28° E.

Rutland Township, 1 mile southeast of West Rutland, S. 70° E.

Leominster Township, road on south slope of Bee Hill, S. 20° W.

Boylston Township, 2 miles southwest of Clinton, on road to West Boylston, 

upturned edges of Worcester phyllite smoothly planed and striated, S. 12° W.

Clinton, half a mile east of Wachusett dam, at east entrance to Boston & 

Maine Railroad tunnel, S'. 2°-3° W.

Bolton Station, smoothly glaciated ledge just south of railroad crossing, 

S. 2°-12° E.

At Clinton, about 120 rods north of the railroad station, where the creek 

crosses North Main Street, is the finest glaciated ledge observed within the 

Quinsigamond quadrangle (PI. XI). The prevailing trend of the striae is 

S. 7°-12° W. In running diagonally up the lower north slope of the smoothly 

rounded ledge the striae have a more southwesterly trend, which shifts 

gradually to a more southerly trend as the abrupt 5 or 6 foot slope is surmounted. Readings at intervals of a few feet from north to south along these 

curved lines show the following changes of direction: 

S. 32° W.-S. 26° W.-S. 13° W. ' 

S. 26° W.-S. 4° W.-S. 2° E. 

S. 40° W.-S. 20° W.-S. 14° W. 

S. 40° W.-S. 20° W.-S 7° W. 

S. 32° W.-S. 26° W.-S. 13° W. 

S. 27° W.-S. 2° W. 

S. 26° W.-S. 4° W.-S. 2° E.

Higher up the top slope from the last reading and crossing were striae 

trending due south, S. 3° E., S. 7° E., and S. 12° W.

Numerous other glaciated surfaces were temporarily exposed in the excavations for the north-dike cut-off of Wachusett Reservoir.

One mile east of Boylston Center, S. 3° W. (Emerson).

At Southboro, on Main Street, about three-quarters of a mile west of the 

center of the village, is a fine example of the results of glaciation. The sur-
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 35

face of the ledge of schist is smoothly rounded, grooved, and scratched with 

striae ranging from S. 2° E. to S. 10° W.

In Worcester and vicinity the effects of glacial abrasion can usually be seen 

wherever the drift covering is stripped from the rock. Striae bearing S. 

5°-10° W. were observed by the writer on the planed edges of the upturned 

phyllite schists a short distance west of the Plantation Street viaduct over the 

Boston & Albany Railroad, south of the State Insane Hospital.

In the southwestern part of Worcester, at the cemetery Notre Dame des 

Canadiens, opposite Hope Cemetery on Webster Street, a glaciated ledge of 

schist was observed just south of Rev.. J. Brauillet's monument, with striae 

bearing due south to S. 10° E.

In the southeastern part of the village of Upton is a ledge of gneiss whose 

surface is grooved in a direction S. 2°-10° W. The surface is so much weathered, however, that it is uncertain whether the markings are the result of 

glaciation.

About 1$ miles farther southeast ledges beside the road show striae trending S. 17° E.

In Woonsocket, R. I., one block west of the railroad station, a glaciated ledge 

of schist and conglomerate is exposed in the east slope of the valley.

Striae having a southerly trend were reported by Robert Robertson in the 

town of Auburn, on the road half a mile northeast of Auburn Station, and also 

in the town of Woodstock, Conn., 1 mile west of the village of Quinebaug.

Edward Hitchcock" cites glacial striae trending nearly due south on the 

eastern slope of a hill in the southeastern part of Sutton.

Glacial striae have been found in the Ware quadrangle as indicated 

below.

Granby Township, south of the east end of the Holyoke Range, S. 8° E. (B. 

K. Emerson).

Granby Township, west end of Forge Pond, S. 15° E. (B. K. Emerson).-

Pelham, west slope of ridge, 1 mile north of Hygeia, S. 15° W. (B. K. 

Emerson).

1$ miles northeast of Dwight station, N. 80° E. (G. H. Barton).

Petersham, S. 5°-20° E. (G. H. Barton).

2 miles southwest of Petersham, south of Fever Brook bridge, doubtful, 

S. 10° W. (W. C. Alden).

3 miles northwest of Barr,e, S. 10° E. (G. H. Barton).

1$ miles north-northwest of Barre, north slope of Alien Hill, S. 10° E. (G. H. 

Barton).

2A miles southwest of Barre, crest east of Pine Hill Brook, S. 50° JB. (W. C. 

Alden).

1£ miles north of Furnace, S. 7°-10° W. (W. C. Alden).

li miles north of Oakham, S. 1° E. (N. £. Shaler's assistants).

1£ miles southeast of Ware, west slope of Coy Hill, S. 10° E. (G. H. Barton).

14 miles north of Palmer, north of C. Kalliher's, S. 40° E. (B. K. Emerson).

3 miles south-southeast of Brookfield on ridge crest, S. 15° W. (W. C. Alden).

C. W. Weld's quarry, li miles southeast of Sturbridge, due south (W. C. 

Alden).

3 miles southwest of Southbridge, south-southwest (W. C. Alden).

As indicated by the trend of the striae and by the orientation of the 

elongated drift hills, or drumlins, shown on the maps, the general

u Final report on the geology of Massachusetts, vol. 2, p. 387, 1841,
36 CONTKIBimONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

direction of the ice movement across the area was southerly, with 

local deflections to the southeast and southwest. In the western part 

of the area the southerly movement was doubtless controlled by the 

great valley of the Connecticut. That there was comparatively little 

movement of the basal ice eastward or southeastward from the valley 

to the uplands on the east is indicated by the rarity of fragments of 

the Triassic sandstone and conglomerate in the drift of the Pelham

ridge.

THICKNESS OF THE ICE.

Concerning the probable thickness of the ice at the time of its 

maximum extension, which is believed to be marked by the outer terminal moraine on Long and Block islands, Marthas Vineyard, and 

Nantucket, certain deductions may be made. Measured on an air 

line in the direction of the ice movement, Wachusett Mountain stands 

about 90 miles from the moraine on Block Island. As the summit 

of this peak, which stands 2,015 feet above sea level, was glaciated the 

ice must have been at least thick enough to cover the summit, and 

it was probably considerably thicker. On the assumption that the 

relative altitudes were about the same as at present, the average slope 

of the ice surface from the terminal moraine on Block Island must 

have been about 22.4 feet to the mile in order to cover the summit of 

the peak; if the average slope was 25 feet to the mile the summit must 

have been buried under 235 feet of ice, a thickness not at all improbable. Mount Monadnock, with its glaciated summit 3,166 feet 

above sea level, stands about 118 miles from the terminal moraine, 

measured along a line only a short distance west of that from Wachusett Mountain. To surmount this peak the average slope of the 

surface of the ice must have been about 26.75 feet to the mile, a slope 

which would have required about 400 feet of ice on the summit of 

Wachusett Mountain and 1,450 to 1,550 feet over the site of Worcester. 

An average slope of 30 feet to the mile, such as was estimated by 

Smock 13 from data obtained in New Jersey and adjacent parts of 

New York, would have given the ice plateau above Mount Monadnock an altitude of 3,540 feet, covering the summit to a depth of 374 

feet. The crest of Wachusett Mountain would have been buried to 

a depth of 685 feet, and at Worcester the ice would have been 1,700 

to 1,800 feet thick.

In existing ice caps, such as that of Greenland, the slope of the 

surface, which is abrupt at the margin, becomes much less as distance 

from the margin increases. In Montana Calhoun 14 obtained evi18 Smock, J. C., On the surface limit or thickness -of the continental glacier .in New 

Jersey and adjacent States: Am. Jour. Sci., 3d ser., vol. 25, p. 339, 1882.

14 Calhoun, F. H. H., The Montana lobe of the Keewatin ice sheet: U. S. Geol. Survey 

Prof. Paper 25, p. 28, 1906.
PHYSICAL FEATURES oir CENTRAL MASSACHUSETTS. 37

dence concerning the marginal slope of the Keewatin ice sheet from 

which he drew the following conclusions:

In the Pondera Basin the slope was about 30 feet to the mile. On Teton 

Ridge the slope, much less exactly determined by the slope of the moraine, 

was about 40 feet per mile, and on the slope of Milk River ridge it was 50 

feet per mile. The most satisfactory determination was made between the 

Sweet Grass Hills and the edge of the ice to the west. * * * In this 

distance [25 miles] the slope of the upper surface of the ice averaged about 

50 feet per mile.

If the average slope is assumed to have been 50 feet to the mile 

for the first 25 miles north of the moraine on Block Island and 22.3 

feet to the mile for the remaining 65 miles to Wachusett Mountain, 

making an average of 30 feet to the mile for the whole distance of 

90 miles, the ice plateau in the southern part of the Quinsigamond 

quadrangle would have had an altitude of about 2,365 feet, and there 

would have been a thickness of 1,800 to 1,900 feet of ice over the 

city of Worcester. Although these estimates give concrete expression to conceptions concerning the magnitude of the ice sheet, it can 

not be assumed that they approach exactness, because of the unknown 

factors involved, such as the attitude of the land surface in Pleistocene time.

PRE-WISCONSIN DEPOSITS. 

LACUSTRINE CLAY.

At only one place in the Ware and Quinsigamond quadrangles 

were materials observed that might be regarded as evidence of a 

stage of glaciation and deglaciation earlier than that during which 

the main deposit of drift was laid down. About a mile southwest 

of Larnedville, at the east side of Little River valley, the Worcester & Southbridge Electric Railway traverses a cut in the south end 

of the ridge. The cut, which is divided by a slight ravine, has a 

maximum depth of 50 feet. At the time of the writer's visit the 

section was partly obscured by wash and a slide, so that the relations of the materials were not entirely clear. In the eastern part 

of the cut there was exposed at the top 15 feet of sand and gravel, 

with a few boulders, poorly assorted and obscurely bedded. Below 

this was 15 feet of fine interlaminated sand and gray clay, intensely contorted (PI. XII, A). The remaining 5 feet of the 

cut below this was obscured by talus. The laminated sand and 

clay formed the core of the section, and the surface sloped down to 

the east and west, so that the overlying gravelly drift extended down 

on either side to the bottom of the cut. Farther west down the track 

in the other part of the cut the contorted laminated materials extended to a level 10 feet lower and formed a core 20 feet in height. 

Mantling the curving surface of these deposits was 30 feet of sandy
38 CONTRIBUTIONS TO GEOGEAPHY OP UNITED STATES, 1923-1924.

gravel drift. The drift here includes beds of clean sand, but elsewhere it is unsorted and appears to consist of pebbly and bouldery 

till, with a matrix of loose sand. The base of the laminated clay 

was not clearly exposed, but at one point it appeared to rest on sandy 

till, cemented so thoroughly as to be difficult to penetrate with a pick. 

The opposite side of the cut appeared to be made up almost wholly 

of sandy till. The altitude of the top of the laminated beds is 

about 640 feet above sea level, and the cut is in the south slope, facing 

an open valley leading southward, so that under present topographic 

conditions ponded waters in which the fine laminated silts might be 

deposited could not be held up to the level of the beds exposed. 

The relations of these deposits are so obscure that accurate conclusions can not be based upon them. They seem to indicate that 

the glacier advanced, depositing the underlying till; that this was 

followed by melting of the glacier, which left the basin closed by 

drift or ice in such a, way as to pond the waters, and deposit the 

silts; and that subsequent draining of the basin resulted in erosion 

of the laminated deposits. A readvance of the ice contorted the 

laminae, and the final melting left the upper sandy till. The underlying till was insufficiently exposed to determine whether or not it 

belonged to- a stage distinct from that at which the main till sheet was 

formed. The laminated silts and the few included crystalline pebbles 

seen did not give evidence of exposure to the weather prior to the 

last advance of the ice, so* that the events recorded here may be 

merely the results of conditions resulting from minor oscillations 

of the ice front, rather than of .distinct succeeding stages of glaciation and deglaciation.

RESIDUAL MATERIAL.

Throughout most of the area the rock surface beneath the drift 

is smoothly planed, or even polished, and striated, and the residuum 

of preglacial weathering has been entirely removed. At a few 

places, however, considerable residual material has been incorporated in the drift, and some yet remains undisturbed between the 

drift and the solid rock. One such exposure was seen on the road 

traversing the slope half a mile southwest of "Oxbridge, where 1 

foot of sandy till overlies 3 to 5 feet of disintegrated gneiss.

'Near the crossroads half a mile east of the south end of Whitehall 

Pond a 15-foot exposure in the north slope of the hill showed the 

following relations: A mass of granite and gneiss with rounded surfaces rises 10 feet into the section. At one side is compact brownishgray till, which is penetrated by a pick with difficulty. Overlying 

the rounded surface is a few inches of stratified sand. At the other 

side, overlying the sand and rock, is 5 to 10 feet of arkose, or sand 

resulting from the disintegration of the gneiss. No drift material
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XII

A. CRUMPLED LAMINATED CLAY, POSSIBLY INTERGLACIAL.

li. ESK.ER SOUTH OF CLINTON, MASS.
U. S. GEOLOGICAL SURVEY BULLETIN 76O PLATE Xm

H A. M. P

Tfoor

MAP OF MASSACHUSETTS SHOWING D1STKIBUTION OF DKUML1NS

Compiled by William C. Alden from observations of several geologists
tT. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XIV

A. PROSPECT HILL, A DHUMLIN NliAIl CHARI/TON, MASS.

£. DRUMLIN NORTHEAST OF GLEASONDALE, MASS.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 39

is commingled with this sand. The cleavage is clearly traceable, and 

a quartz vein 1 inch thick extends vertically through it for 2 or 3 

feet. The quartz of this vein preserves its alinement, though broken 

into fragments, showing that the material has not been disturbed 

since its disintegration, unless it was moved as a whole when 

cemented by ice.

At Joseph Bugbee's, 2 miles south of North Braintree, in the Ware 

quadrangle, is exposed about 15 feet of thoroughly disintegrated 

brown coarse-grained schist, which is probably preglacial residuum.

About 2-| miles northwest of Barre an excavation in the east slope 

of Moose Brook valley gave the folio wing section:

Section of drift northtoest of Barre.

Feet. 

Buff sandy, bouldery till______________________ 2

Gray disintegrated schist, with some till mixed ir> upper part 7

This material grades downward into solid undecomposed schist. 

The upper part of the distintegrated schist is somewhat disturbed 

and contains undecomposed fragments, and the till consists almost 

entirely of local material, so that the two are scarcely distinguishable.

WISCONSIN DRIFT.

THE GROUND MORAINE.

GENERAL CHARACTER.

Overlying the uneven surface of the indurated rock formations 

throughout the two quadrangles is a mantle of till composed of 

heterogeneously mixed clay, sand, gravel, and boulders of various 

lithologic character. Most of this material probably lodged beneath 

the advancing glacier as ground moraine. Some of it, together with 

most of the boulders scattered on the surface, was deposited when 

the ice finally melted away. This deposit is generally thin upon the 

crests and slopes of the ridges, where rock ledges are exposed at 

short intervals. The valleys are largely occupied by glacial stream 

deposits laid down during the melting of the ice. At a few places 

30 to 50 feet of unstratified till is exposed, and some wells are known 

to have penetrated 90 to 100 feet of drift, of which at least a large 

part is probably till. Numerous local accumulations of drift also 

occur as drumlins and drumloidal hills 20 to 150 feet in height, which 

may be composed almost wholly of till. It is doubtful, however, if 

the average thickness of the drift in central Massachusetts is more 

than 10 or 15 feet, and it may be less. Though the matrix is generally a compact clayey till, on close examination it is seen to be made 

up of rather coarse undecomposed or partly decomposed grains of
40 CONTRIBUTIONS TO GEOGEAPHY OF UNITED STATES, 1923-1924.

crystalline rocks. This being the case, the upper part is likely to be 

loose and .sandy. The difference in texture of the upper part is also 

accompanied by a change in color, from the prevalent dark gray of 

the lower part to light buff or grayish buff. This difference in 

texture and color is partly a result of weathering and partly a consequence of the fact that the last contribution of the melting glacier, 

when the advance had ceased, escaped the compression consequent 

on being overridden by the ice. The depth of the looser weathered 

zone is rather variable. In places the gray tint extends upward to 

the grass roots. Elsewhere the gradation from gray to buff occurs 

at depths of 3 to 10 or even 15 feet. The change is everywhere a 

gradation; at no place does the upper buff part of the till appear to 

be a distinct deposit.

The till is composed predominantly of rock material of local character. It contains comparatively few rock fragments that can not 

have been derived from formations exposed within the immediate 

region, and usually the till is composed largely of rock such as occurs 

directly beneath or very near the exposure. Over the belts of granite 

and gneiss the till is light gray and consists largely of granitic material. Over the schist the till is more brownish, and schistose fragments prevail. Over the phyllite the matrix is apt to be more compact and in places has a greenish tint.

Besides being compact and difficult of excavation the till may show 

a rude cleavage parallel to the surface, evidently the result of pressure of overriding ice.. Other than this cleavage the typical till 

shows no definiteness of structure. It is not uncommon, however, for 

associated sand and gravel to occur in lenses or layers in the midst 

of the till, or for the material to be semistratified throughout, showing the close association of ice and water action in the process of 

deposition. In some places bands of associated material are crumpled and kneaded in with the till, as if it had been disturbed by the 

forward crowding of the ice. Generally the rock fragments in the 

till are fresh and sound and retain the marks of glacial abrasion. 

Locally, however, it contains crystalline pebbles that are in a stage 

of incipient disintegration, so that they crumble beneath the hammer. 

Throughout most of the area the residuum of preglacial weathering 

has been entirely removed, but at a few places considerable residual 

material has been incorporated in the till, and some yet remains 

undisturbed between the till and the solid rock.

DBUMLINS.

The general topographic expression of the ground moraine is that 

of a mantle, which has smoothly flowing contours where it covers the 

rock ridges with sufficient thickness to disguise their angularities.
PHYSICAL FEATTJRES OF CENTRAL MASSACHUSETTS. 41

In places, however, local thickening of the drift sheet results in certain more or less distinct topographic features of its own. These 

are the drumlins, the distribution of which throughout Massachusetts is shown in Plate XIII. About 275 of those in the area under 

discussion are sufficiently well formed to be indicated on the detailed 

map (PL VI, in pocket). In this mapping the writer's observations 

have been supplemented by those of Prof. George H. Barton, as 

shown on unpublished maps. Though scattered through much of the 

eastern two-thirds of this area, they are most numerous in the eastern 

part of the Ware quadrangle and the western part of the Quinsigamond quadrangle. Besides those mapped, other hills, apparently of 

drift, show drumloidal profiles as seen from one direction, but their 

contours do not conform to the drumlin type as known in various 

parts of the country. The drumlin is a product of the glacial advance, the overriding ice tending to give to the accumulation of drift a 

form that offers relatively small resistance to the forward movement 

of the ice. As a result of his observations and studies, particularly 

in Wisconsin, the writer has come to regard as a typical drumlin a 

hill of glacial drift that 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 

that is, the end that was opposed to the ice advance 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 that formed it. 

Most drumlins, however, vary more or less from 'any set type, and 

there is also some difference of opinion among geologists as to the 

use of the term " drumlin," some including under this designation 

hills of glacial drift that have little definiteness of form or regularity 

of orientation. Owing to this difference of interpretation, maps of 

the same area by different workers may not entirely agree in the hills 

shown as drumlins. Though by no means wishing to limit the use 

of the term to typical forms such as are denned above, the writer 

regards approximately oval or elliptical contours and orientation 

of the longer axis approximately parallel to the direction of ice 

movement as essential characteristics of this class of hills. The drift 

hills of other forms and orientation are not here included.

The graceful contours of the drumlins add much to the beauty of 

the landscape, the most striking feature being the regular curves 

of the crest line (PI. XIV, A, #), as seen in either longitudinal or 

transverse profile. The basal outline as drawn upon the map may 

appear distorted, because of the inequalities of the surrounding surfaces to which the side slopes decline. Usually contour lines above 

the base are more regular than the line marking the foot of the 

slopes. For a comparison of the dimensions of the 14.6 drumlins of 

the Ware quadrangle with the 160 drumlins of the Quinsigamond
42 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

quadrangle rough measurements were made on the topographic maps 

on a scale of 1:62,500, referred to on page 14. The results are 

presented in the following tables:

Dimensions of drumlins in the Ware and Quinsigamond quadrangles.

Width. ....... .......do...

Height ............... d o ...

Ware quadrangle.

1. 050-4, 755

415-2.310

15-180 

2,505

1,200

Quinsigamond quadrangle.

825-4,950

495-4, 125

30-245 

2.805

1,485

Ratio length to height .....

Ware quadrangle.

56

2.8

44.5 

21.5

Quinsigamond quadrangle.

100

1.8

26 

14

From this comparison it appears that the drumlins of the Ware 

quadrangle are on the average somewhat smaller and relatively 

more slender than those farther east. There is, however, so much 

variation in both quadrangles that the difference is not at all marked.

Perhaps the type defined above is too restricted. In this area the 

tendency is toward elliptical rather than oval contours, and several 

hills are approximately circular, the diameters being nearly equal 

in all directions. Most of the drumlins are elongated in the direction of the ice movement, but there is a notable absence of those forms 

in which the lee ends are drawn out into long tapering tails. The 

crests of a few of the. drumlins are cut by channels of subsequent 

formation. The character and relations of these channels are discussed below, in connection with the description of eskers.

In only one drumlin within the area was there noted a good exposure of the internal structure at the time of the writer's examination. This is the drumlin east of Plantation Street in Worcester. 

This hill has a height of about 90 feet. In the lower west slope a 

large excavation has been made for brick clay, giving a 50-foot 

section. No ledge of rock is exposed, the whole face being solid 

dark-grayish till, hard to dig with a pick, except the upper 5 to 

8 feet, where the till is lighter in color, or dull buff, and of somewhat 

looser texture. Most of the pebbles are 2 to 4 inches in size, though 

a few boulders were seen, including one 8 feet in length. No 

assortment, bedding, or other evidence of water action was noted, 

but an indefinite cleavage due to pressure is present. There is no 

evidence that the hill has a rock core, though the presence of exposed 

ledges within distances of 1,350 feet or less in almost every direction 

makes it probable that bedrock lies not far below the base of the 

drumlin. Similarly, in the slopes of the other hills regarded as drumlins no ledges were exposed, though rock crops out within short 

distances of the bases of many of them. Though the absence of 

rock cores has not been proved, the drumlins are believed to be made
PHYSICAL FEATUBES OF CENTRAL MASSACHUSETTS. 43

up wholly of glacial drift. As will be seen from the map, the 

orientation of most of the longer axes is approximately parallel 

with the directions of striae observed on glaciated rock ledges. 

These show that the ice moved across the area in a general southerly 

(direction. There is, however, considerable local divergence, some 

7axes swinging off 50° to 70° east of south. Throughout the district 

there is a general development of smoothly rounded and elliptical 

crests, but examination shows that most of the hills and ridges not 

mapped as drumlins are composed of abraded rock ledges only thinly 

covered with drift. The drumlins appear to be local accumulations 

of till that have been symmetrically molded by the moving ice. The 

particular causes that led to such accumulations in one place rather 

than another are not well understood, although there has been a good 

deal of speculation among geologists in regard to this matter. Many 

of the drumlins appear as lobes of the lateral or terminal slopes of 

ridges of the dissected upland in such a position that they might 

well be regarded as but thinly veneered lobes of rock. The only 

reason for considering these hills to be drumlins is their form and 

the absence of outcropping rock in them. Indeed, without test 

borings it is quite impossible to determine that the hills have no 

rock cores, for practically all stand on bedrock bases.

The drumlins occur indiscriminately in all sorts of topographic 

situations on broad upland crests, in narrow valleys lying alongside slopes of broad rock ledges with one lateral slope much longer 

than the other, banked against the rising north slopes of rock elevations, or tailing down the lee south slopes to lower levels.

TERMINAL MORAINES. 

MODE OF OCCURRENCE.

Whenever the rate of melting of the ice became approximately 

the same as the fate of forward movement, the glacial margin 

either halted or oscillated back and forth over a narrow belt of 

country, and the drift brought forward and released there tended 

to accumulate in the form of a more or less irregular ridge or 

range of hills, known as a terminal moraine. The main terminal 

moraines that mark the outer limit of advance of that part of the 

ice sheet which traversed this region lie to the south, on Long Island, 

Block Island, Marthas Vineyard, and Nantucket, and partly on the 

coast (fig. 4). Such moraines were also formed at stages of halt 

or of readvance and halt of the ice margin, which interrupted the, 

general northward recession of the ice front across the country during the final melting of the glaciers, and these terminal moraines have 

been designated moraines of recession. No continuous, well-defined 

terminal moraines have been traced across the Ware and Quinsiga-
44 CONTBIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

mond quadrangles, though numerous isolated deposits of drift 

occur which if properly correlated with other features give some 

clue concerning the configuration of the glacial margin and the process of final deglaciation in the area. The distribution of these deposits is shown on the maps, and lines showing a provisional correlation of these with other features of the district are shown on 

Plate VII (in pocket). Topographically these deposits are very insignificant, so that their presence would scarcely be noted except by 

one making a systematic study of the country, yet geologically they 

are of some importance. In regions where the inequalities of the 

preglacial topography are largely obliterated by a heavy mantle 

of drift the moraines formed at the several positions of halt of 

the ice front are usually distributed along lines transverse to the direction of the ice advance, forming more or less continuous marginal moraines. In this area, on the contrary, where the valleys 

and ridges developed prior to the ice invasion were simply mantled 

by the drift and are still the predominant topographic features, 

almost all the deposits, of whatever character, formed in connection 

with the retreat of the ice front are distributed along the valleys 

approximately parallel to the direction of the ice advance, rather 

than along the transverse lines that must have defined the retreating margin. The correlation of these features is considered below, 

in the discussion of the Pleistocene history (pp. 93-104).

Two examples of transverse moraines were observed 3 to 6 miles 

southeast of Wachusett Mountain. From a point 1£ miles south 

of West Sterling a belt of sags and low gravel swells may be traced 

from the bottom of Stillwater Valley southwestward up the slope 

and across the crest to the valley of Governor Brook, and thence 

across the south end of Barrett Hill to the valley in the vicinity 

of Quinapoxet village. About 2 miles farther north a similar belt 

may be traced down the east slope of Stillwater Valley, 1£ miles 

below East Princeton, across the stream, up* the west slope, and 

across the ridge to the large morainal filling in the valley of East 

Wachusett Brook.

The valley deposits that are considered terminal moraines consist 

very largely of sand and coarse gravel partly sorted and stratified 

and partly mixed with bouldery drift in a confused dump. The 

surficial configuration is/ one of knolls and ridges of gravel (kames) 

interspersed with irregular or bowl-like depressions (kettles, fig. 6), 

many of which contain small ponds and marshes. The difference 

in height between these humps and hollows ranges from 5 to not 

much more than 100 feet, so that their topographic expression is 

generally peculiar rather than imposing. These features are distinguished from kame terraces or morainal terraces (p. 47), which 

closely resemble them in surface form, in that the moraines generally
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 45

filled the valleys from side to> side, in places completely blocking 

them. Many of them are also distinguished by their relations to 

valley terraces of outwash gravels at whose head they stand (p. 56). 

They are differentiated from lacustrine deposits by the positions in 

Avhich they occur and usually by their heterogeneous composition and 

pitted or otherwise uneven surface expression, indicating the presence of the ice in immediate connection with their deposition. The 

occurrence of these morainal features at intervals in the valleys indicates a succession of stages of more rapid melting or of less rapid 

forward movement of the ice, during which the glacial margin was 

melted back without halting sufficiently long to accumulate characteristic morainal deposits, alternating with stages.of decrease in 

melting or increase in the forward movement of the ice, so that much 

debris was brought forward and left as the ice front oscillated 

back and forth across zones ranging from a fraction of a mile to 

several miles in width.

The terminal moraines are not only mostly confined to the valleys, 

but they are not generally heaped up in the shape of narrow transverse ridges such as form distinct morainal dams across valleys in

..-.._........_..-._

FIGURE. G. Diagram showing probable origin, of many kettleholes. A, Detached block of 

glacier ice ; B, same block after part has been melted and the remainder covered with 

sand and gravel ; G, depression, resulting from complete melting of the ice. (After 

M. R. Campbell.)

many other glaciated regions. Instead, the drift is spread out along 

the valleys for distances of 1 mile to several miles, forming knolled 

and pitted tracts, in which the difference in altitude of the several 

parts is only that between the knolls and depressions.

TERMINAL MORAINES OF QUINSIGAMOND QUADRANGLE.

Notable examples of terminal-moraine deposits occupy the socalled "Auburn River" valley almost continuously from Worcester 

to the vicinity of North Oxford, a distance of 7 miles, and occur in 

Quinsigamond Valley both north and south of the lake and at numerous other places in the Quinsigamond quadrangle. (See PI. VI.) 

Some of these deposits are described in connection with other features.

Masses of ice buried in the morainal debris appear to have remained intact for a long time after the disappearance of the glacier 

from their immediate vicinity. Otherwise the morainal drift in the 

92818° 25 4
46 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

open valleys would have been more cut by stream channels.. This 

is especially true of the deposits in the head of Quinsigamond Valley 

southwest of Boylston Center, where but for the continuance of the 

buried ice masses intact as part of the drift dam, the water of 

the glacial lake in Nashua Valley would not have been held up 

to the level of the terraces formed while the waters were discharging through this outlet (p. 63).

TERMINAL MORAINES OF WARE QUADRANGLE.

Some of the best examples of terminal moraines in the Ware 

quadrangle are here noted. At the bend in the Quinebaug Valley 

west of Southbridge is a considerable mass of drift, which appears 

originally to have completely blocked the valley. An excavation for 

road material showed that the lower 10 to 15 feet of the 30 to 40 foot 

section is mostly unstratified sand and pebbly clay, crumpled and 

kneaded together, as if by forward crowding of the ice. Above this 

is bouldery till with streaks of stratified sand and clay kneaded 

into it.

A morainal ridge 80 to 100 feet in height, pitted with shallow sags, 

lies across the valley south of Quacumquasit Pond, north of Sturbridge.

Morainal drift forms the retaining dams at the south side of 

Little Alum Pond and on the southwest side of Alum Pond, continuing thence 3 miles up the valley in Brimfield Township. At 

South Spencer station and extending thence north to Spencer and 

east to Cranberry Eiver is a considerable morainal deposit. Near the 

railroad kettleholes 10 to 30 feet deep pit the material, which consists principally of sand and gravel, as shown by a 30-foot railroad cut and other exposures.

A morainal ridge with marked kames and abundant great boulders 

occurs near Tufts Brook, 3 miles south of Warren and West Warren.

South of South Monson a morainal fill completely blocks the 

valley for a distance of 3 miles, except for a narrow gorge cut in it 

by the stream. The full thickness of the drift is not known, but some 

of the hills rise 150 feet or more above the level of the stream. Cuts 

show the material to be sand, sandy till, and boulders.

About 1| miles southeast of Palmer, at the electric-railway power 

house, the valley is abruptly narrowed by a ridge of drift, now cut 

through by the stream. Railway and wagon-road cuts expose 100 

feet or more of loose gray sandy, bouldery till. A mile farther east 

the slope north of the railway rises 100 to 150 feet, to the crest of a 

narrow kame ridge, north of which is an area of strongly marked 

kames and kettles.

To the north up the valley toward Palmer Center is a flat partly 

eroded terrace of outwash sand and gravel, which merges into an-
PHYSICAL FEATUEES OF CENTEAL MASSACHUSETTS. 47

other area of pronounced kames and kettles consisting of hills of 

sand and gravel interspersed with sags, in some of which are ponds. 

This is clearly a terminal moraine filling the valley, which is from 

half to three-quarters of a mile in width, from side to side, as far 

as the road leading northeast from the village. North of this road 

the surface lowers to a partly eroded terrace of sand and gravel, 

which was probably formed in a glacial lake held back of the moraine 

as the ice front retreated along the valley to the north. There was 

here a close association of lacustrine deposition and marginal glacial 

deposition, the material being principally sand with some gravel and 

including large boulders. The knolled and pitted character of the 

deposit shows that it was made immediately along the glacial front. 

In the valleys to the east are similar and probably contemporaneous 

moraines.

At the southwest end of Springfield Beservoir, northeast of Ludlow 

Center, is a considerable morainal fill. Excavations in the ridge 

which extends from this cut into the lake and on which are the filter 

beds show stratified sand and gravel dipping northeastward, indicating clearly that the detritus was washed in this direction from the 

east front of the glacier that occupied the Connecticut Valley, to the 

west.

Other morainal features occur in the valley extending southeastward from Coldbrook, north of the creek at South Barre, in the 

valley 2 miles northwest of Hardwick, and at Dudleyville in Leverett 

Township, where a narrow ridge marks the northwest boundary of a 

temporary glacial-lake basin.

The deposit extending for a distance of 4 miles along the Swift 

River valley above and below West Ware is probably a terminal 

moraine, as it has an uneven surface and nearly fills the narrow 

valley. It can scarcely have been formed as a kame terrace at the 

sides of a lobe of ice in the valley. The narrow inner valley traversed 

by the streams was undoubtedly excavated by the escaping glacial 

waters as the ice front was melted back toward the north and also by 

subsequent erosion.

KAME TERRACES.

ORIGIN.

Closely associated with the terminal moraines and usually merging into them are similar features lying along the side of the valleys 

but not extending across the full width. These are kame terraces or 

morainal terraces. They differ from ordinary stream terraces in 

several respects. The component material, which is glacial drift, 

is commonly coarse and bouldery and poorly assorted, and though 

mostly stratified, it generally shows disturbed stratification and may 

be partly unstratified. The surfaces are not uniformly flat but have,
48 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

especially along the margin toward the axis of the valley, the knolled 

and pitted configuration characteristic of moraines. The altitudes 

of such terraces on opposite sides of a valley do not usually correspond, as in lake or stream terraces, where the deposit is controlled 

by a common water level, and there may be variation in the gradients 

on the two sides, such as in lake or stream terraces might be taken 

as evidence of subsequent deformation.

After the ice had melted off the uplands for some miles to the 

north lobes of the glacier still remained in the valleys. The waters 

from the melting ice flowed down the slopes and ravines and washed 

more or less drift onto the margins of the valley lobes, where they 

lay against the rock slope (fig. 7, A). The waters thus gathered 

into considerable streams along this contact here flowing over a bed 

of ice, there swinging against the valley slope spreading out the

FiGCim 7. Diagram illustrating formation of kame terraces. A, Terrace formed at the 

side of a melting glacial lobe in a valley; B, view up the valley after melting of ice has 

caused slumping of overlying material and formation of " ice-contact" slopes below 

> the terraces.

sands and gravels and forming deposits a quarter of a mile to half 

a mile or more in width. At the south end of each ice lobe the 

stream deposits merge into the moraine, filling the valley from 

side to side. Here the melting ice .left the drift piled in irregular 

knolls and ridges, except as spread out smoothly by the glacial 

waters. The sheet of debris lapped over the margin of the melting 

lobe, filling in crevasses and burying many ice blocks left detached 

by the melting. Through the spaces between the piles of drift and 

over the buried ice blocks the water escaped down the valley. Channels were cut, and meandering streams developed flood plains, leaving irregular remnants of moraines on either side. In time the 

buried ice masses melted, and as they did so the overlying drift 

settled and slumped down, leaving depressions (kettleholes) with 

abrupt gravel slopes. With the further wasting of the valley lobe
PHYSICAL FEATURES OF CENTBAL MASSACHUSETTS.' 49

the marginal stream deposits were left banked along the valley 

slopes (fig. 7, B). That part of the material resting on the rock 

maintained its form, except as included masses of ice left pits when 

they melted, but that part resting on the ice settled and slumped 

irregularly, developing the knolled and pitted surface to which is 

given the name " kame terrace " or " morainal terrace."

KAME TERRACES OF QOINSIGAMOND QUADRANGLE.

The largest kame terrace in the Quinsigamond quadrangle is that 

extending from Bolton Station, east of Clinton, northeastward along 

the east slope of the valley to Vaughn Hill. It probably originally 

continued as far south as " The Acre" and filled the gorge now 

occupied by Nashua River at Clinton. Railroad cuts northwest of 

Bolton Station and other excavations expose the stratified and 

cross-bedded sand and gravel composing the deposit. The undisturbed higher parts have flat terrace tops, which increase in altitude 

from about 380 feet above sea level at Bolton Station to 400 feet 

at the Bolton Industrial School, southwest of Vaughn Hill. Toward 

the river the surface has a steep slope, much lobed and irregular, as 

a result of the slumping when the retaining wall of ice melted away, 

and dissected more or less by subsequent erosion. This terrace as 

seen from the west is a marked topographic feature 100 to 150 feet 

above the valley floor, with the wall of the valley rising above it 

on the east. The gravel composing the terrace was deposited in a 

trough between the upper east slope of the valley and the sloping 

surface of the ice, which was at that time so far reduced that it 

lay as a lobe only about 3 miles in width, extending several miles 

beyond the main front of the glacier down the valley to the vicinity 

of Clinton. The lake occupying Nashua Valley at that time discharged through the south-dike outlet to the Assabet basin, and 

the marginal stream forming the terrace doubtless poured much of 

its gravel-bearing water through the cols and down the valleys 

converging at West Berlin.

About 3-| miles southwest of Clinton a, much smaller marginal 

deposit merges into a flat terrace or delta at an altitude of 480 feet 

above sea level. Apparently this deposit was formed where the 

marginal stream discharged into the open lake at the ice front when 

the outlet was southward through Quinsigamond Valley. So also on 

the north side of Fort Meadow Reservoir, 2 miles south of Hudson, 

a pitted deposit on the lower slope merges at the west into a finely 

developed terrace or delta where a stream at the side of a small ice 

lobe in the valley dropped its burden in the ponded waters. An 

excavation in the abrupt marginal shope showed stratified gravels 

dipping to the west at an angle of 30'°.
50 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

KAME TERRACES OF WARE QUADRANGLE.

Bordering the lower valley slopes south of Brookfield and East' 

Brookfield and converging thence southward to the moraine at the 

head of Quacumquasit Pond are kame deposits, evidently formed 

along the lateral margins of an ice lobe that lay in the valley.

Similar deposits bordering the east side of the valley at Warren 

were probably formed as a terrace as the ice front lay along the foot 

of the slope.

When the uplands to the east were largely freed from ice a lobe 

still extended southward in the broad valley of the Connecticut. 

Where the margin of this lobe lay along the rocky slopes rising on 

the east there was good opportunity for the formation of glacial 

features of this class. The best-developed kame terrace is near the 

State line, extending southward from Scantic into the town of 

Seiners, Conn. Here fully 90 per cent of the drift is composed of 

fragments of red sandstone and conglomerate from the Triassic beds 

of the great valley. Farther north, near North Wilbraham and 

Ludlow Center, in the town of Granby, and near Dwight, similar 

terraces were also formed successively as the ice was melted slowly 

back across the upland while yet projecting farther southward in 

the valley.

ESKERS AND GLACIAL STREAM CHANNELS. 

ESKERS OF QUINSIGAMOND QUADRANGLE.

There are within the Quinsigamond quadrangle about half a dozen 

small eskers a mile or more each in length and a few shorter fragments. The origin of these features is discussed "below (p. 54), and 

their locations are shown upon the map. One of the best examples 

occurs at Hadwen Park, in the southern part of Worcester. This 

appears as a narrow ridge on the south bank of the stream, whence 

it extends southward in a sinuous course entirely through the park. 

Near the park shelter it is 30 feet high, with narrow crest and sides 

sloping down at angles of .30° to 35°. At one point it swings in an 

oxbow curve close to the hill slope on the west and then away from it, 

as if this slope had deflected the esker-forming stream. Cuts at the 

south line of the park at Clover and Webster streets show the ridge 

to be composed of unsorted fine to coarse gravel, in which the largest 

stones are 1£ feet in length. An examination of 100 pebbles taken 

at random from one of the cuts showed 57 to be of Worcester phyllite, 25 of granite, 8 dense greenish schist, 7 gneiss, and 3 quartz. 

Between Webster and Boyce streets the ridge has mostly been cut 

away by erosion, but east of Boyce Street it continues with slight 

relief eastward, and then southward about half a mile, merging with 

the sags and swells of the morainal topography.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 51

About 4| miles farther 

east, near the south end of 

Lake Quinsigamond, just 

east of the corner of Lake 

Avenue and Harrington 

Street, is a narrow sinuous gravel ridge that extends south to the electric 

railway on Grafton Street 

and thence through the 

woods to the head of 

Dorothy Pond. In some 

places this ridge is 30 to 

40 feet high; in others it 

spreads out indefinitely, 

blending with the swells 

of the morainal topography.

About 3£ miles northeast of North Grafton a 

sinuous ridge of gravel 

runs southward from the 

electric railway 450 to 550 

yards and then branches 

into three distinct ridges 

10 to 30 feet in height, 

which continue south about 

half a mile and merge into 

the morainal deposit at 

the head of Miscoe Brook 

valley. The easternmost 

of these ridges swings 

across the north-south road 

and extends up a slope 

20 to 30 feet in height 

onto the south end of the 

morainal ridge east of the 

road.

About 2£ miles still farther east, another system of 

eskers extends from the

southern part of Westboro ____________________ 

to Westboro Reservoir. fe 

Here there is an interesting association of eskers with drumlins (fig. 

8). The foot of the east slope of the finely formed drumlin iust south
52 CONTKIBUTIONS TO GEOGKAPHY OF UNITE!) STATES, 1923-1924.

of Westboro is closely followed by a sharp, narrow esker ridge of 

gravel. The road passes through a narrow break in this ridge, and 

east of the road the ridge continues south about 1,000 feet. At this 

point it is joined by a similar ridge, which comes from the northwest directly down the lee (southeast) slope of the second drumlin 

of the group and crosses the road. A third branch heads between 

the second and third drumlins and joins the others east of the road. 

These ridges are in places 30 feet high, and cuts show them to be 

composed of fine and coarse gravel and small boulders. A fourth 

branch or loop of the system is traversed for 300 yards by the eastwest road and joins the others at two points. For 300 yards east of 

the bend in the road the trunk esker lies along the slope. Then it 

swings to the south across the valley. Here it evidently formed a 

dam, holding the lakelet in the basin to the west until erosion cut 

an outlet through the ridge. South of the creek the esker climbs the 

slope to a height of 70 to 80 feet, then shifting a little it runs along 

the slope, is cut through by a creek, and finally merges into a terminal 

moraine surrounding Westboro Reservoir. To reach this moraine 

the esker makes an ascent of about 100 feet in three-quarters of a 

mile, and 80 feet of the ascent is accomplished in less than 450 yards. 

There are two small eskers about 1| miles southwest -of Hopkinton, 

in a shallow valley. One of them is traversed by the north-south 

road throughout its length of three-quarters of a mile. These eskers 

end within 450 yards of a small morainal deposit that occupies a sag 

between two hills.

Between 3 and 4 miles southwest of Uxbridge two eskers, each 

about a mile in length, lie beside brooks and near and parallel to 

ridge slopes and terminate in a broad gravel deposit that is partly 

flat and partly knolled and pitted like a marginal moraine.

About a mile west of Gates Crossing, in Leominster Township, is 

a finely formed esker 15 to 35 feet in height and 1 mile in length, 

which divides the small reservoir and runs thence soui:h to the col 

between Fall and Wekepeke brooks. Here it spreads out along the 

lower east slope and ends indefinitely. Three-quarters of a mile to 

the south is the well-developed terminal moraine surrounding the 

Clinton Reservoir. Small eskers border the brook in the valley above 

East Princeton and north of Brigham Pond, in Hubbardston, and 

others occur at several places associated with moraines,. The eskers 

in Nashua Valley south of Clinton described by Crosby are now 

mostly submerged by the Wachusett Reservoir (PI, XII, B),

ESKERS OF WAKE QUADRANGLE.

Eskers are rare within the Ware quadrangle. The few small examples that have been observed are described in the order of their
PHYSICAL FEATUBES OF CENTRAL MASSACHUSETTS. 53

development as the ice front retreated that is, from southeast to 

northwest across the area.

The south end of Hamilton Reservoir, in the town of Holland, is 

divided by a sinuous gravel ridge, which extends southeastward half 

a mile and merges with a pitted frontal terrace of gravel.

At 3 miles southeast of Wales a similar small esker merges with 

a small terrace near the State line..

Near the west side of the ponds half a mile northeast of Sturbridge 

a small sinuous gravel ridge, followed for half a mile by the road, 

marks the. position of a stream of glacial water emerging from its 

ice channel at the moraine upon which the village stands.

A small esker emerges from the little road pond south of the 

Quacumquasit Pond moraine and extends thence about a mile southward to the north end of Cedar Pond, where it merges into outwash 

gravel. Cuts at the north end of this esker exposed fine brown 

angular arkose gravel resembling coarse sawdust. At the south end, 

near Cedar Pond, the material is coarse morainal gravel.

In Monson Valley there is a deposit probably formed, at least in 

part, as an esker by glacial streams that flowed southward in the ice 

in the valley and probably discharged at the glacial front as it stood 

ut the moraine at South Monson. Near the old mill at North Monson 

the ridge of sandy drift stands 100 feet above the country on the 

east. From the crest it spreads out to the Avest across the electric 

railway to the rocky slope like an uneven terrace. Cut through 

by th& creek at the old mill, the ridge crest reappears on the east side 

of the stream, between the wagon road and the railroad, and extends 

thence southward 1£ miles. Beyond this for half a mile it appears 

to have been largely removed by erosion. A section of the narrow 

ridge near the mill pond at South Monson, where the esker-forming 

stream must have reached the moraine, shows 20 feet of bouldery 

till overlying 20 feet of stratified sand, the bedding of which dips 

southward, in the direction of the flow. At the north side of the 

cut there is an appearance of crumpling, as if due to crowding of 

the ice when the till was dumped on top of the esker sands. When 

first formed this may have been a Well-marked, definite esker through 

its full length, but with the further melting of the ice the deposition 

of terrace gravels along the valley sides rendered - the esker less 

distinct.

In the valley just west of the junction of Beaver Brook with Ware 

River an esker ridge forms the margin of the terrace. A mile to 

the south this ridge flattens out to a pitted terrace, and this in turn 

to a fine flat terrace just north of the railroad. This terrace is evidently a delta deposit formed by the discharge of the esker stream 

into a lake at the ice front.
54 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

Two miles north of the railway bridge at Bondville a small esker 

about half a mile in length is associated with the kame deposits west 

of Swift River.

OBIGIN OF ESKERS.

All the eskers of this area are composed of a mixture of waterworn 

rock fragments of varied lithologic character such as constitute other 

parts of the water-laid glacial drift of the region. These fragments. 

range from grains of sand to boulders 1£ feet in length. The 

material, though waterworn, is not usually stratified in undisturbed 

layers. The deposits follow narrow, sinuous, and sometimes branching courses like channels of streams, but the gravel instead of lying 

in channels is heaped up in sharp, narrow ridges, many of them 30 

to 35 feet high, and with slopes about as steep as the gravel will lie. 

These eskers are believed to be the result of the deposition of gravel 

by streams of glacial water flowing in channels or tunnels in the ice, 

the melting of whose walls allowed slumping of the gravel into the 

form of ridges. Their location, usually in valleys, cols, or basins 

in the drift near and parallel with the axes of the depressions, leads 

to the inference that the streams were sufficiently near the base of 

the ice for their courses to be controlled by the topography beneath

the ice, and most of them were within less than 50 feet of the base. ' \

In such places as the channel in the drumlin crest at Gleasondale 

(p. 55) the stream must at first have been at. least 100 feet above 

the base of the ice north of the hill. The same must be true of the 

stream forming the esker which makes an ascent of 100 feet to reach 

the moraine at the "Westboro Reservoir (fig. 8), unless the water was 

forced up the slope in a rising tunnel under hydrostatic pressure, and 

to furnish this pressure the stream must have had an even higher 

level nearer its head. The drumlin on whose lee slope one of the 

branches of this system of eskers begins rises about 100 feet higher 

than the moraine at which the esker ends. This crest is not channeled, 

and the esker is traceable only down the lower slope from a point 

about on a level with the terminus at the moraine, so that it is not 

known what was the original level of the channel in the ice. The 

ending of most of the eskers in or near terminal-moraine deposits 

or their merging into sand plains formed in ponded waters shows 

that they were formed at positions of halt of the ice front during the 

general progress of final deglaciation of the area. As the margin of 

the ice was undoubtedly thinned by melting, a frontal slope probably 

rose gradually from the terminal moraine and bordering lakes, and 

the streams that formed the eskers, but few of which are more than 

a mile in length, may have flowed down this frontal slope, the deposition of gravel in the. channels taking place only where the streams 

crossed the exposed edges of the drift-bearing layers of the lower 

100 feet or so of the ice.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 55

GLACIAL STREAM CHANNELS.

At several places within the area hilltops are cut by eroded channels, which must have been developed when the relations of the 

drainage from the melting glacier were such that streams were held 

by the ice in positions to flow over what are now the tops of hills. 

One of the most interesting of these channels is at Gleasondale, in the 

township of Hudson. This channel, with others of similar character, 

has been described by Barton.15 North of the railroad is a double 

drumlin known as Orchard Hill, which rises 100 feet above Assabet 

Eiver. One ascending the abrupt east slope is surprised to find the 

east crest cut longitudinally by a narrow, slightly sinuous channel 

having a maximum depth of 27 feet. The channel begins about 75 

feet above the base of the north slope, and except for a few feet at 

this end, due probably to recent deepening, the bottom has a continuous southward slope. There are three sags in the bottom between 

which the depression is slightly shallower. Near the south end of 

the channel a small elongated knoll occurs in the sag, appearing like 

the beginning of an esker. Beyond a short interval a small eskerlike gravel ridge about 5 feet high continues down the sag to the 

street, beyond which is a gravel terrace spread out like an esker delta 

formed in a glacial lake. A little brook issues from the sag beside 

the ridge, and erosion has deepened the depression along this drainage line. The relations here show that at the time of the erosion of 

this channel the ice enveloped Orchard Hill and a stream was flowing in a tunnel or channel in the ice about 100 feet above the base. 

This stream in cutting down its ice channel encountered the crest of 

the hill and there began the excavation of the channel in the drift, 

which it continued down the south slope. The gradient was so high 

that the channel was swept clear of debris, except on the lower slope, 

where erosion ceased and gravel began to be deposited. It is not 

perfectly clear that the partly eroded gravel terrace extending to the 

abrupt marginal slope south of the electric railway is a delta formed 

by this glacial stream, though it appears to be. As discussed below 

(p. 74), the terraces of the Assabet Valley show that a glacial lake 

occupied the basin as the ice front gradually withdrew from it, and 

just prior to the opening of the present channel at Rockbottom the 

col traversed by the railroads west of Gleasondale formed a channel 

connecting the lake on the west with one on the east. The flat terrace on which is the highest part of the village stands about 230 feet 

above the sea, somewhat higher than most of the gravel deposits of 

the ^icinity. This terrace was clearly formed in the body of water,

15 Barton, G. H., Glacial origin of channels on drumlins: Geol. Soc. America Bull., 

vol. 6, pp. 8-13, 1895.
56 CONTRIBUTIONS TO GEOGRAPHY OP UNITED STATES, 1923-1924.

and its character, altitude, and location directly opposite the channel cut in the drumlin crest and merging into the slight esker heading in this channel are most readily explained by regarding it as a 

delta formed where the stream of glacial water debouched from its 

channel of drift and ice into the lake at the glacial front.

STREAK TERRACES. 

LOCATION.

Certain terraces in this area were at least in part the product of the glacial waters after they had left the immediate 

vicinity of the ice front. In the smaller valleys in the southern half 

of the area, most of which drained southward, are deposits of sand 

and gravel which in some places head in pitted morainal tracts 

and in others have no definite connection with such tracts. As the 

ice front retreated up the valleys, here and there the drainage was 

so blocked by earlier deposits that waters were ponded and fine 

laminated sand and sandy clay were deposited, sometimes with included berg-dropped boulders. Near the exposed silts or overlying 

them are coarse gravels and boulders. These terraces, as is well 

illustrated in the valleys of West River, Warren Brook, and Center 

Brook, above and below Upton, are thus composites, and the surface 

configuration is partly of sag and swell type and partly flat and 

terrace-like. After dropping their load the waters proceeded to 

erode the deposit farther down the valley, so that it is now cut 

through by a flat-bottomed channel of varying width through which 

the present streamlets meander.

Blackstone Valley became an important line of glacial drainage 

as soon as the retreating ice front permitted. In consequence, from 

the vicinity of Ironstone northward to its junction with Quinsigamond River, near Fisherville, the stream is bordered by terraces. 

From Ironstone to Goods Hill, 2 miles north of Uxbridge, there is 

one well-developed terrace about 30 feet above the broad flood plain 

that borders the stream (PI. XV), and remnants of another appear 

still higher. Above Goods Hill there is no terrace corresponding 

to the highest farther south. The upper terrace here is the same as 

the second from the top to the south. The latter terrace is broad 

and well marked. Above Fisherville and Saundersville the definite 

terrace form disappears and the gravel merges into morainal deposits. The material composing the terraces is principally stratified 

sand and fine to 3-inch gravel. In places boulders occur embedded 

in the deposit, and they are generally plentiful on the surface.

From the character of these features it appears that they are 

essentially the same as those of the West River valley, but they have 

suffered greater modification by erosion. The remnants of the upper
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 57

terrace below "Oxbridge have the 

pitted and uneven surface of morainal deposits or kame terraces. 

The second terrace developed by 

erosion of the upper has a broad, 

flat top and is a typical abandoned 

flood plain. Before the water had 

entirely cut away the upper terrace it began to cut into the second 

terrace and developed the present 

flood plain, 25 to 30 feet below. 

Above Uxbridge the terrace is flat 

and in places more than half a mile 

in width.

OKIGIN.

The conditions of development of 

such terraces are illustrated in 

Figure 9. During the retreat of 

the ice front along the valley from 

Woonsocket to the vicinity of 

Uxbridge morainal and kame terraces were formed. The water after 

depositing its load began to cut 

farther down the valley, and as the 

ice continued to retreat northward 

the flood plain (now the second 

terrace) was extended to Uxbridge. 

Above Uxbridge the waters spread 

out the gravel of the upper terrace, while they were eroding farther south. This process continued 

northward to the junction of the 

Blackstone and Quinsigamond valleys, the work of erosion lagging 

behind that of deposition. As the 

retreat continued the divergence of 

tributary valleys brought in waters 

from a greater extent of the glacial 

front and augmented the eroding 

power, while the deepening of the 

lower valley increased the gradient 

and led in turn to a partial erosion 

of the second terrace. The discharge of the glacial waters down 

Quinsigamond Valley continued until the opening of the south-dike
58 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

outlet for the lake in Nashua Valley, so that the lower terrace, or 

present flood plain, was extended north to Fisherville. Above this 

point it is less well defined, though the channel extends northward 

to Lake Quinsigamond.

BOULDERS.

On the final melting of the ice boulders were left so abundantly 

scattered over the surface of the drift that they must have added 

greatly to the difficulties experienced by the early colonists in clearing their land for cultivation. Their industry, supplemented by that 

of succeeding generations, however, has gathered most of these into 

the walls by which the fields are inclosed (PL XVI, A). In some 

places the boulders are not only very numerous but so large as not to 

be readily moved (PL XVI, B). In the Ware quadrangle such bigboulders occur just west of Palmer, 2 miles east of New Braintree, 

3 miles north of North Brookfield, on Buck Hill 1£ miles southwest 

of North Brookfield, 2 miles west of Brookfield, 1 mile southwest of 

South Spencer, and just north of Sturbridge. The boulders are 

not distributed in definite belts but are scattered indiscriminately. 

At these places they consist largely of very coarse granite and 

are not uncommonly 10 to 15 feet in diameter. Schist, which splits 

up more readily than granite, usually constitutes the smaller boulders. In the lee of the exposures of the very coarse Coysi Hill 

granite, notably large boulders of this rock occur. These are especially abundant at points 2 and 3 miles south of West Warren, where 

one boulder of coarse granite gneiss beside the road on a northwest 

slope measured 15 feet in height and 90 feet in circumference. North 

of Ridge Hill, 3 milesi in a direction south by east from Dana, large 

boulders are very abundant upon a small morainal deposit. In 

a marshy depression back of Charles Griffin's house is one of the 

largest boulders seen in this region. This rock, which is a coarse 

pegmatite, is about 18 feet high, 12 to 15 feet thick, and 45 to 50 feet 

long. A large block is split off one end and tipped over 1 to 3 feet 

from the main mass, and in this space a good-sized tree is growing. 

A very large boulder also occurs in. the valley half a mile north 

of Barre post office. One of the finest examples occurs at a point 

1£ miles north of Gilbertville, on the ridge 650 feet west of George 

P. Manly's house (PL XVII, A). Perched upon the crest of the 

ridge at this place is a boulder of coarse granite 89 feet in circumference, with diameters of 29 and 31 feet, and a tape line drawn over 

the top from ground to ground measured 49 feet. Split off one end 

of this boulder is a. mass 53 feet in circumference, with a maximum 

thickness of 7 to 8 feet.

Some of the large boulders were left by the melting of the ice 

perched in what, but for their great masses, would be very insecure
BULLETIN 700 PLATE XV

FLOOD PLAIN AND STREAM TERRACE.
TT. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XVI

A. WALLS OF GLACIAL BOULDERS INCLOSING FARM LANDS NEAR DANA, MASS.

S. GLACIAL BOULDERS NEAR PRINCETON CENTER, MASS.
U. S. GEOLOGICAL STJRVEY BULLETIN 760 PLATE XVII

A. GLACIAL BOULDER NORTH OF GILBEllTVILLE, MASS.

£. PERCHED BOULDERS 3 MILES NORTHWEST Ol'1 HAKRE, MASS.
PHYSICAL FEATTJBES OF CENTRAL MASSACHUSETTS. 59

positions. One such boulder, locally known as the " rocking stone " 

and pictured by Edward Hitchcock,16 is a very curious example ^of 

one boulder perched upon another (PI. XVII, B). It occurs on 

H. L. Harris's land, 3 miles northwest of Barre, near the road to 

Dana. The upper block, 5 by 8 by 8 feet in size, is of coarse granite 

and rests on a block of granite gneiss 4| by 8 by 10 feet, and this 

in turn on the rounded surface of a ledge of granite. It is strange 

indeed that the melting of the inclosing ice should let down the one 

block upon the other in a position so precisely balanced that it has 

so remained through all the succeeding centuries.

Hitchcock 17 also mentions a boulder in Berlin that was said to 

weigh 160 tons and yet could be moved by a boy 6 years old. Another in Berlin, 1 mile east of the meeting house, on the road to 

Bolton, was described to him as " a boulder of granite 17 feet long 

and 27 feet in circumference, resting upon granite or gneiss, apparently just ready to fall, and yet five men with levers were unable 

to throw it from its base."

EXTINCT GLACIAL, LAKES. 

CHANGES IN ELEVATION OF THE LAND.

Geologists have collected numerous data tending to show (1) that 

the northeastern part of North America, including much of New 

England, was depressed under the weight of the vast accumulation 

of ice that formed the great ice sheets; (2) that, as the ice melted 

and the glacial margin receded northward, marine waters spread 

over the lower parts of the depressed land; and (3) that after the 

land was relieved of the weight by the melting of the glaciers it 

rose again, in somewhat the same manner that a rubber ball in which 

the pressure of a thumb has made an indentation in one side regains 

its spherical form after removal of the pressure. Whatever the 

cause may be, it is clear that there was depression and reelevation 

near the end of the glacial epoch. The amount of such reelevation 

increased gradually northward from practically nothing in southern New England to 500 or 700 feet in the northern parts of Vermont, New Hampshire, and Maine and to 1,000 feet in the region 

between St. Lawrence Eiver and James Bay. The degree to which 

the part of Massachusetts under discussion shared in the depression 

and subsequent reelevation is not certainly known. It has been 

claimed that tidal waters extended far up the Connecticut Eiver 

valley; that estuaries headed well within the area here described, 

one in the Nashua Valley and another in the Blackstone Valley; and 

that the east coast of Massachusetts was then in the longitude of

18 Final report on the geology of Massachusetts, vol. 2, p. 376, 1841. 

"Idem, p. 375.
60 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

Marlboro, with an embayment in the Assabet Eiver basin. It may 

be stated, however, without discussing the subject fully, that the 

evidence presented for so extensive a postglacial submergence of 

eastern Massachusetts is regarded by many geologists as insufficient to support the conclusions drawn. So far as the deposits 

found in the Ware and Quinsigamond quadrangles are concerned, 

it seems to the writer that adequate explanation of their character 

and mode of occurrence is to be found in the relations of the receding ice front to the configuration of the land. These relations evidently must have been such as to result in the formation of many 

temporary bodies of fresh standing Avater, in which lacustrine deposits would be laid down at various levels conforming to those of 

the available outlets.

Waters escaping from a melting glacier produce a variety of land 

forms, determined by the presence or absence of open channels that 

permit fiowage directly away from the vicinity of the ice front.

In the valleys draining northward or northeastward the retreat 

of the ice front as the glacier melted freed the southern parts of the 

basins from ice while yet the old outlets were blocked, thus causing 

the formation of temporary lakes at the glacial front, and in these 

lakes were formed glacio-lacustrine deposits. When the basins were 

wholly freed of ice the lakes were drained, and the deposits, were thus 

exposed to erosion by the streams. The most notable of these temporary lakes in the Quinsigamond quadrangle were those occupying 

the Nashua and Assabet river basins, which have, for convenience, 

been designated glacial Lake Nashua, and glacial Lake Assabet. The 

relations of these lakes to the ice front are illustrated in Figures 

10 and 11 and Plate XVIII.

GLACIAL LAKE NASHUA. 

DEPOSIT OF THE PRELIMINARY OR QUINAPOXET STAGE.

The freeing of the Nashua River basin from ice began in the town 

of Holden (see map, PI. VI), and here in the valleys of the Quinapoxet and its southern tributaries are found the initial deposits to 

be correlated with the history of glacial Lake Nashua. The cols at 

the heads of the southern tributaries served as the initial outlets 

for the glacial waters. One of the first of these outlets to° be used 

was the col above Holden Reservoir, at the head of Tatnuck Brook. 

This has an altitude of about 820 feet above sea level. Another was 

the col traversed by the railroad at Holden, at an altitude of 760 feet. 

This leads to the col south of Chaffin Pond, at about the same altitude. Both led waters from the lake to the Blackstone Valley at 

Worcester. The drift surrounding the drumlms at Jefferson and 

Eagleville and occupying the valley north and west of Chaffin Pond 

consists very largely of stratified sand and gravel, but here and there
PHYSICAL FEATUBES OF CENTRAL MASSACHUSETTS. 61

much coarser material and boulders are intermingled with the fine 

deposits, and the surface aspect is that of a terminal moraine. Evidently the material was deposited in immediate connection with the 

ice front, so, that many ice blocks were buried in it, and the melting 

of these ice blocks produced the pitted topography. From the south 

side of Chaffin Pond a small flat covered with sand and gravel leads 

to the col. On the northeast slope of Davis Hill, west of Unionville, 

are two flat sand and gravel terraces with abrupt margins toward 

the valley. The upper one, which is a quarter of a mile in width, 

has an altitude of 720 feet above sea level (by barometer). These 

terraces were apparently formed in ponded waters after the ice had 

withdrawn slightly from the slope of Davis Hill. They are lower 

than the col south of Chaffin Pond, and may mark positions of the 

water when it was beginning to escape about the north slope of 

Maiden Hill to the cols north-of Summit Station.

West of the north end of Maiden Hill there is a notable filling of 

sand and gravel in the valley, through which the Quinapoxet has cut 

a sharp narrow channel 100 to 140 feet in depth. Above this drift 

dam the valley bottom is flat and nearly half a mile in width. This 

deposit has a very even horizontal crest line at an altitude of about 

600 feet above the sea, except where a few knolls rise above the general 

level. Close examination shows it to be pitted with kettles and cut by 

erosion. The upper surface corresponds with that of a flat gravel terrace about one-eighth of a mile in width on the north side of the 

stream, and the relations indicate that the two were originally continuous, the valley being completely blocked up to this level. The 

material of the terrace is apparently a marginal glacial deposit 

formed in ponded waters. At a corresponding level is a slight beachlike ridge of gravel near the house on the north slope of Maiden 

Hill. An outlet that would determine the level of the lake at 600 

feet above the sea is not found west of that at the head of the short 

east branch of Gates Brook, 1-| miles south of Boylston Common. 

The lacustrine deposits east of this drift dam are at lower levels, so 

that it would seem that while this filling was being made the ice must 

have occupied the valley to the east, its margin extending southeastward along the slope to the col just west of that traversed by the 

Boston & Maine Railroad, but it blocked any egress through the col 

at Quinsigamond Valley, southwest of Boylston Center. From the 

col southeast of Boylston Common gravel extends down the valley of 

Great Brook to the Quinsigamond Valley.

DEPOSITS OF THE BOYLSTON STAGE.

In Nashua Valley below Oakdale terraces occur at intervals along 

the south side 160 to 180 feet above what was the stream channel 

before the submergence resulting from the construction of Wachu92818" 25 5
62 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

sett Eeservoir. These terraces are about 480 feet above sea level, a 

position which corresponds with the flat tops of the higher parts 

of the deposits in the col southwest of Boylston Center, whence it 

appears that at the time of the formation of these high terraces this 

part of Nashua Valley was at least partly free from ice and was 

occupied by a lake discharging through the Boylston outlet over the 

morainal drift and buried masses of ice and down Quinsigamond 

Valley (fig. 10, A). From the relations of the deposits to the several 

villages in the town of Boylston Crosby applied the name Boylston 

to this stage of the lake. The maximum extent of the lake at this 

stage is shown on the map of the Quinsigamond quadrangle (PI. 

VI). Deposits of sand and gravel, considerably pitted and eroded, 

extend eastward from the drift dam in Quinapoxet Valley described 

above (p. 61) to Oakdale, where the cemetery and upper part of 

the village are located on a flat terrace at 460 to 480 feet. On the 

south side, next the stream, the structure of the deposit is partly exposed in an abrupt 60 to 80 foot erosion slope. The material is 

largely sand, with some gravel, stratifield as in the topset and f oreset 

beds of a delta. The beds dip east, showing that the sand and gravel 

were washed into the lake from the west, and it is probable that 

they were derived from the erosion of the drift dam described above, 

after the water had lowered to the Boylston stage.

From the Industrial School 'eastward to West Boylston stratified 

sand and gravel occur in low swells along the north slope of the 

valley up to about 480 feet above sea level (fig. 11). East of the. electric railway these deposits merge with a moraine and an esker, 

which extend north through the col to Stillwater River. No deposits 

of this stage were noted about the south and east slopes of French 

Hill. Southeast from Boylston Common to Muddy Brook, above 

the 400-foot level of the Clinton terrace, a deposit of sand and 

gravel about half a mile in width rises to a nearly uniform height 

of 480 to 490 feet against the higher slope. The surface is more or 

less uneven and shows numerous kettleholes. The deposit was probably formed as a terrace between the valley slope and the ice front as 

it began to withdraw from the moraine in the col southwest of 

Boylston Center. There is no indication that it originally extended 

northward entirely across the valley, though it may have had a 

somewhat greater extent than now, especially where is now the submerged valley of Muddy Brook. Sand and gravel extend northeastward from the outlet along the east side of the valley. At West 

Boylston the cemetery stands upon a finely developed terrace at 480 

feet. The material exposed in the upper 100 feet of the abrupt erosion slope that part above the water level at the time of the writer's 

visit is principally sand, with some fine gravel and a little fine
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 63

laminated sandy clay, stratified in layers dipping toward the axis of 

the basin.

Between 1 and 2-£ miles northeast of Boylston Center broad remnants of terraces of the Boylston stage are traversed near their
64 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

shoreward margin by the electric railway. One of these remnants 

is about 300 acres in extent. The surface altitude is about 460 feet 

(by barometer), which would indicate that by the time of its formation the drift barrier in the Boylston outlet had been cut down somewhat by the outflowing waters (fig. 10, B). This broad terrace is 

directly opposite the small kame terrace and delta occurring at the

enter Partly submersed Terminal moraines

terraces and delta and kame terraces

sand plains (partly concealed

V O ^ by ice)

FIGUKH 11. Diagram illustrating relations of the ice front to glacial Lake Nashua near 

the end of the Boylston stage.

Boylston level on the west side of the valley 3£ miles southwest 

of Clinton. These deposits, with the gravel extending along 

the east side of the valley to the south-dike outlet, are the most 

northerly deposits to be correlated with the Boylston stage. The 

northeast margin of the broad terrace is abrupt and lobed and drops 

down 70 feet to the level of the Clinton terrace. This scarp is an 

ice-contact slope and apparently marks the latest position of halt of 

the ice front before the opening of the south-dike outlet (fig. 11).
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 65

That it is at an ice contact is further shown by the fact that into 

it merge two eskers, which when seen were partly submerged by the 

waters of Wachusett Eeservoir (PI. XII, B}. These eskers mark 

the position of streams that discharged into the lake from the ice 

front and spread their detritus in a broad delta.

DEPOSITS OF THE CLINTON STAGE.

Because of the position of the south-dike outlet and the fine preservation in the vicinity of Clinton of the terraces formed when the 

waters discharged through this outlet, this stage of the lake has been 

designated by Crosby the Clinton stage. Prior to the building of 

the south dike of Wachusett Reservoir the outlet stood about 360 

feet above the sea, but it was probably about 30 feet higher when 

first opened, inasmuch as the Clinton terraces southwest of the outlet 

have altitudes of approximately 400 feet. (See Pis. VI and XVIII 

and fig. 10, 0.) From the vicinity of the bridge at Boylston Common a flat terrace 150 to 650 feet in width extends southeastward 

along the south side of the valley, between the abrupt erosion slope 

that drops 60 to 80 feet to the submerged bottom of Nashua Valley 

on the north and the marginal slope of the higher Boylston terrace on 

the south, as far as the submerged valley of Muddy Brook. The old 

stone church stood on a slight remnant of this terrace near the 

north end of the bridge, but east of this point for about half a mile 

the terrace has wholly disappeared. From the south end of French 

Hill northeastward to a point due west of the south-dike outlet a 

narrow strip remains at 395 to 405 feet above sea level. Slight 

remnants of this lower terrace also occur on the east side of the 

valley between Muddy Brook and the south-dike outlet.

At the time of the writer's visit the river valley was submerged 

up to the 367-foot level, leaving the upper 30 feet of the material 

underlying the Clinton terrace exposed in sections kept clean by 

frequent slumping. Southeastward from Boylston Common to the 

vicinity of the quartzite hill the upper 5 to 15 feet consists of gravel 

ranging from fine pebbles to cobblestones. Beyond this point the 

upper gravel is absent from the section. Beneath the gravel is 

5 to 30 feet of stratified sand in delicately rippling layers, with 

the cross lines showing that the direction of wash was toward the 

southeast. The lower part of the section, ranging in thickness from 

a few inches to 10 feet above the water, is made up of fine interlaminated sand and clay. The clay layers in places contain abundant 

clay-iron concretions formed about tubelets.

The opening of the south-dike outlet must have caused a rapid 

lowering of the lake from the 480-foot level to the 400-foot level. 

This change increased the gradient of all the streams flowing into 

the lake very notably, so that they attacked the drift deposits in
66 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

their valleys with renewed energy, cutting them away and depositing the detritus in the lake. Drainage from the ice front contributed much, and the lake waters themselves accomplished more 

or less erosion of the deposits of the Boylston stage along their 

shores, so that probably the deposits described above filled the valley 

from side to side almost if not quite up to the water level. Indeed, 

the lake may have been entirely filled up so that in its place a stream 

meandered over a broad flood plain. The gravel deposits mark the 

final stages of the filling.

From the latitude of the south-dike outlet, where Nashua River 

swung toward the east side of the valley, northward nearly to 

South Lancaster, the deposits are much better preserved and are 

spread out 1 to 1^ miles in width, filling the broad ancient valley 

west of Clinton from side to side except where interrupted by iceblock depressions and small eroded ravines (PL XVIII). At the 

point where this broadening begins the terrace drops about 15 feet 

by a short slope to an altitude of 380 to 385 feet, so that this 

plain is submerged when Wachusett Reservoir is filled up to> the 395- 

foot level. Crosby 18 has discussed in detail these deposits of the 

Clinton stage.

Through an east-west belt about 330 feet wide just north of this 

short slope the terrace is closely pitted with kettleholes (PI. XIX, 

A), but beyond this to the submerged valley of Cunningham 

Brook pits are fewer. These pits indicate the burial of abundant 

large masses of ice and the continuance of these masses intact while 

the plain to the north was being built up. The structure and composition of the deposit exposed above water level at the time of 

the writer's visit are essentially the same as those noted farther 

south, except that the beds dip generally toward the south, or in 

a direction away from the ice front. The structure shown in Plate 

XIX, B, is that of fore-set and bottom-set beds of a delta, the 

bottom-set beds consisting of alternate layers, one-fourth to 1 inch 

thick, of buff brown sand and bluish slightly clayey sand. A little 

to the east of the section shown in Plat© XIX, B, the stratified sand 

is overlain by horizontal beds of gravel in which the largest cobbles 

are 1 foot in diameter.

This delta plain is separated from that to the north by the submerged valley of Cunningham Brook. Crosby's examination of this 

valley before its submergence led him to regard it as virtually a 

fosse between a normal steep and irregular ice-contact margin on the 

south and a normal gentle and lobate frontal slope of the delta 

plain on the north, thus marking the next position of halt of the ice 

margin in its retreat.

18 Crosby, W. 0., Structure and composition of the delta plains formed during the 

Clinton stage in the glacial lake of Nashua Valley: Tech. Quart., vol. 16, pp. 240-254; 

vol. 17, pp. 37-75', 1904.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 67

North of this valley is the extensive plain across which is built 

the north dike of Wachusett Eeservoir. The surface of the eastern 

part of this plain has been considerably modified by grading incident to the construction of the north dike and cut-off. The structure and composition of the deposits were thoroughly explored 

by Crosby in the trench for the main cut-off, which had an aggregate length of 9,556 feet and a maximum depth of 60 feet, and in 

that for the shorter secondary cut-off, and by the examination of 

samples from more than a thousand wash-drill borings systematically 

distributed on the plain with an average depth of 83 feet and a maximum depth of nearly 300 feet. The general altitude of this plain 

is about 380 to 385 feet, there being a gentle slope toward the south, 

and except for ice-block depressions, in one of which lay Sandy 

Pond and the channel (now filled) that connected it with Coachlace. 

or Clinton Pond, the plain is continuous across the ancient valley 

from east to west, entirely surrounding a group of rock ridges 

that rise above it. South of Wachusett dam this plain terminates 

in a maze of interlacing kames and kettles, now submerged. At 

the north it ends in a pitted ice-contact slope at the south margin 

of the Coachlace Pond. The basin occupied by this pond is regarded 

as a fosse marking the next position of halt of the ice front. That 

part of the plain west of the rock ridges is but little broken by depressions, and borings show the thickness of the deposits to range 

from a few feet to about 190 feet. The axis of Sandy Pond and 

adjacent depressions was found to coincide approximately in position and trend with the deep preglacial bedrock gorge of Nashua 

River, discussed above in connection with the Tertiary drainage system (pp. 23-27). The depressions are not directly above the buried 

gorge but are superposed, with 100 to 130 feet of assorted drift intervening, upon a distinct bedrock terrace several hundred feet wide 

and having an altitude of 190 to 210 feet, which separates the gorge 

from a buried ridge of schist that rises within 100 feet of the surface of the plain. This broken east half of the delta plain, according to Crosby, overlies an unusually rugged bedrock surface, with 

a maximum relief of nearly 300 feet and a corresponding variation 

in the thickness of the drift above it. The surface of the rock beneath this drift was found to be fresh and unweathered.

Exploration of the deposits beneath the north-dike plain showed 

that the filling of the ancient rock valley was almost all water-laid 

drift, till being notably absent. The till mantle extending down 

the side slopes into the valley dies out within a short distance beneath the stratified deposits. Southward down the sloping bedrock 

plain the till increases somewhat, and in two or three of the most 

southerly profiles it is practically continuous above the rock and 

ranges in thickness from. 2 to1 30' feet. The water-laid drift that
68 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

forms the bulk of the filling ranges from, coarse gravel at the top to 

very fine sand and clay at the bottom, assorted and stratified in topset, fore-set, and bottom-set beds as in a normal delta. The borings 

did not as a rule reveal the attitude or dip of the three groups of 

beds, so that conclusions relative to their thickness were based on the 

assumptions that medium and fine sand belonged especially to the 

fore-set beds, rock flour to the bottom-set beds', and very fine sand in an 

intermediate position, marking the transition from fore-set to bottomset beds. These assumptions were sustained by observation wherever sections of the deltas were seen. Crosby says that although the 

trend of the cut-off was at most points transverse to the direction of 

delta growth, the walls of the great trench, 30 to 60 feet deep, showed 

in general below the coarse gravel of the horizontal top-set beds, 

rarely more than 10 to 15 feet thick, southward-sloping layers of 

medium to fine sand. Concerning the structure of the deposits 

Crosby says in part:

To summarize, the north-south profiles of the westerly portion of the northdike plain reveal a normal delta structure, with the bottom sets rising to the 

southward and both the bottom setsi and fore sets becoming, on the average, of 

finer texture in that direction. East of the cemetery ridges, but heading 

against the same ice contact on the north, the growth of the delta was similar 

but chiefly easterly to a lateral ice contact along the western borders of 

Coachlace and Sandy ponds. East of the ponds the development was again 

normal, from a head ice contact on the north and with a lateral ice contact 

on the west. In this case it may be noted in addition that the profiles cross othe 

head contact and thus give in that direction coarser material and more complete sections than for the westerly profiles.

Between the bottom-set beds of rock flour and the bedrock in many 

places was found a basal layer of gravel and coarse sand ranging 

from a few inches to several feet in -thickness. This material was 

thought to be the detritus spread over the intervening tract during 

the recession of the ice margin from the head of one delta to the head 

of the next delta of the series.

Crosby's studies also afforded him the basis for certain deductions 

concerning the origin of the kettleholes that pit the delta plain. 

Beneath the floor of the channel (now filled) that connected Coachlace and Sandy ponds was found 120 to 130 feet of very fine sand 

and rock flour regarded as forming bottom-set beds. The top of this 

deposit also was found to extend out under the bordering plain at 

approximately the same level, with, in general, no indication of slope 

toward the great, kettle. Above this level as a rule were only the 

normal foreset materials, chiefly medium and fine sands, overlain by 

5 to 20 feet of coarse top-set beds. From this relation Crosby concluded that

The depression .s clue to the melting of a block of clear ice at least 50 feet 

thick, which rested on the impalpable bottom sets at about elevation 325 while
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 69

it became inclosed by the advancing foresets. That the ice block rose above 

the surface of the water and thus escaped complete burial seems to be proved 

by the general absence of top-set detritus on the floor of this trough.

The altitude at which the mass of ice must have lain led to the conclusion that it was a stranded berg, rather than a residual portion of 

the decaying ice sheet. Beneath another kettle borings showed practically a complete absence of bottom-set sediments and a more or 

less distinct inward slope of fore-set and top-set beds, indicating that 

here the ice block, 50 feet or more in thickness, was probably a 

residual mass resting on the valley bottom and buried by fore-set 

and top-set materials, which settled as the ice melted. The relations 

of deposits beneath other kettles cut through by the cut-off trench 

indicated that ice masses were stranded on the top of the bottom-set 

deposits and subsequently buried by fore-set and top-set materials. 

In one place the structure showed that a comparatively small block of 

ice was stranded and buried and then melted, causing the settling 

of the overlying beds, and the depression was then filled by continued 

deposition. Crosby concluded " that the kettles of the north-dike 

plain are probably as diverse in origin as in form " and that " pretty 

much all known or suggested conditions of kettle formation were 

realized simultaneously in this limited area."

North of the transverse part of Coachlace Pond the gravel plain, 

more or less broken and uneven, extends to the line of the New York, 

New Haven.& Hartford Railroad. North of the railroad on High 

Street a 40-foot slope leads up to a broad, flat plain nearly threequarters of a mile in extent and having an elevation of nearly 360 

feet above sea level, or approximately that of the lowest part of the 

south-dike outlet, and terminated at the north by an abrupt slope, 

40 to 100 feet in height, which is partly an ice-contact slope and 

partly eroded.

These several delta plains, each heading at an ice-contact slope 

and fosse, mark the progress of the retreat of the ice front bordered 

by Lake Nashua, while the waters discharged through the southdike outlet. North of South Lancaster for a distance of 4 miles, 

in .the whole valley, 2 to 2£ miles in width, no terraces or deltas 

occur at levels corresponding with the south-dike outlet. North and 

northwest of Whittemore Hill, however, in the town of Lancaster, 

partly within the Quinsigamond quadrangle, occur similar pitted 

delta plains of sand and gravel at altitudes of 300 to 400 feet that 

is, at levels somewhat higher than the last of the delta plains south 

of South Lancaster. The occurrence of only deposits of a later and 

lower stage in the valley north of Clinton over so broad an area, 

although the sand and gravel plains north and northwest of Whittemore Hill rise 100 to 180 feet above the valley bottom, is regarded 

as evidence that the sand and gravel of these plains may have been.
70 CONTKIBUTIOFS TO GEOGKAPHY OF UNITED STATES, 1923-1924.

laid down while yet the ice lobe in the valley extended south to the 

ice-contact slopes near Clinton 19 (PI. XVIII). These high gravel 

terraces have in part ice-contact slopes at the north and in part 

merge into deposits showing morainal topography. The stream that 

formed them must have been connected with the open lake near 

Clinton by way of the valley of Wekepeke Brook and the col southeast of Pratt Junction, which has an altitude of 420 to 430 feet, 

or along the east slope of Ballard Hill. No evidence of the flow of 

glacial waters along this slope or across the crest of the hill was 

noted, but in the valley of Wekepeke Brook considerable deposits of 

sand and gravel occur. These deposits, however, which are mapped 

as glacio-lacustrine, rise to somewhat higher levels than the sags in 

the crest of Ballard Hill and are in part at least morainal and of 

earlier deposition. As the ice melted in the valley north of Clinton 

the water in Wekepeke and North Nashua, Valleys lowered to the 

level of the south-dike outlet, causing partial erosion of the deposits 

and forming a second terrace, at 360 feet above sea level, north of 

the stream east of Gates Crossing. No stratified materials were 

noted on the slopes of Ballard Hill.

Between 2 and 3 miles north of Still Eiver station is a broad terminal moraine, which is the first indication of a definite halt of the 

ice front in the valley in a distance of 6 miles northeast from the 

ice-contact slopes near Clinton.20 As the ice melted the lake extended northward, yet through this whole distance no deltas or terraces other than those indicated appear to have been formed. The 

reason for this is not apparent. Gravel extends up all the valleys 

tributary to the lake on the north and west, notably in North 

Nashua Valley, so that most of the coarser material carried by the 

streams in these valleys may have been dropped before it reached 

the lake. Moreover, some of the drainage from the frontal slope'of 

the ice margin may have been diverted eastward away from Nashua 

Valley at points north of the Quinsigamond quadrangle.

The only deposit representing this latter part of the Clinton stage 

is fine laminated silt or clay, now overlain by sand and gravel of a 

terrace of a later stage. The best exposure of this clay seen by the 

writer was at the New England Brick Co.'s plant, half a mile west 

of Still River Station, where an excavation was being made in the 

abrupt margin of a broad terrace (PI. XX, A}. Here the upper 

10 to 12 feet consisted of cross-bedded sand and fine gravel, forming 

the terrace top. Beneath this and above the level of the floor of the

10 Professor Emerson states in a personal communication that a study of the area to 

the north of the Quinsigamond quadrangle has made it appear probahle that these deposits 

are connected with the Clinton stage.

^Atwood, W. W., The country around Camp Devens (description printed on back of 

topographic map of Camp Devens and vicinity), U. S. Geol. Survey, 1919.
U. 8. OEOLOOICAL SURVEY 

EXPLANATION

BULLETIN 760 PLATE XVIII

Partly submerged Terminal moraines 

terraces and delta and kame terraces 

sand plains (prtly concealed 

oy ice)

JMAP ILLUSTRATING THE RELATIONS OF THE ICE FRONT TO GLACIAL LAKE NASHUA AT THE CLINTON STAGE.
TJ. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XIX

A. KETTLE HOLES IN SAND AND GRAVEL SOUTH OF CLINTON, MASS.

IS. FORESET AND BOTTOMSET BEDS OF SAND PLAIN 3 MILES SOUTHWEST OF

CLINTON, MASS.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XX

A. CROSS-BEDDED SAND OVERLYING LAMINATED CLAY, STILL RIVER 

STATION, MASS.

B. LAMINATED AND CRUMPLED LACUSTRINE CLAY, STILL HIVICIl 

STATION, MASS.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 71

valley was exposed 12 to 14 feet of blue stoneless laminated clay, 

with alternate layers slightly sandy and less dense. The depth to 

which this clay extends below the level of the valley floor is not 

known, but at one point a low ridge of stony blue clay (glacial till) 

rises a few feet above the floor, and the laminae of the overlying 

clay dip with the slope of its surface. About the middle of the section are three beds, 1£ feet, 1 foot, and 10 inches in thickness, in 

which the laminae are closely crumpled in little folds (PI. XX, B). 

Between, above, and below these beds are regular undisturbed laminae. The little folds are not regularly overthrust toward the south, 

nor is there any coarse or unassorted drift on the several contorted 

layers, or other evidence of a readvance of the ice front, such as would 

indicate that the glacier had thrice overridden the laminated clay. 

It is more probable that the contortions are due to the repeated 

grounding of icebergs or ice floes on the soft clay bank. The rising, 

sinking, and turning of such grounded masses with the movement 

of the water might contort the clay laminae to a depth of a few 

inches, as seen here. Continued deposition after each interruption 

covered the disturbed beds with regular laminae. If it is assumed 

that each layer of the laminated clay represents the total accumulation of a year's slack-water deposition of fine sediment in the lake, 

just as each of the concentric rings in the trunk of a tree represents 

a year's growth, a rough estimate might be made of the minimum 

duration of the later part of the Clinton stage of glacial Lake 

Nashua, while the ice front stood at the moraine between Still River 

Station and Ayer and before the waters shallowed enough to permit 

the deposition of the cross-bedded sand and gravel that overlies the 

clay.

The clay is exposed "in the bank northward for some distance beyond the limits of the Quinsigamond quadrangle. Just south of the 

clay pit the surface of the clay drops down in the section, so that 

for some distance north of the road the whole section consists of 

stratified sand and gravel. Similar clay was also exposed at an old 

brickyard on the east side of the valley, about three-quarters of a 

mile north of Still River Station. It is reported that clay was dug 

for brick nearly 45 years ago in the lower slope of Whittemore Hill, 

at the Burbank place.

One mile northeast of Lancaster a pit just east of the railroad, 

owned by E. & R. N. Farnsworth, exposed 8 feet of laminated clay 

beneath 5 feet of sand and gravel when seen by the writer.21 Except for the upper foot, in which some pebbles are mixed, the clay,

31 Alden, W. C., Fuller's earth and brick clays near Clinton, Mass.: U. S. Geol. Survey 

Bull. 430, pp. 402-404, 1910.
72 CONTRIBUTIONS TO GEOGRAPHY OP UNITED STATES, 1923-1924.

which is used for fuller's earth, is almost wholly without stones, 

though occasionally berg-dropped boulders are found in the deposit. 

It is said that a thickness of at least 26 feet was shown at one point 

by excavation and boring, and that the deposit thins up the slope to 

8 feet at the west side of the railroad, the average being perhaps 15 

feet. Lower down the slope to the east the stony blue till is exposed. The laminae are slightly undulating, and it is said that in 

places in digging they have been found folded and tipped up on 

edge. These beds of laminated clay were evidently deposited as silt 

in the open lake, free from coarse detritus except that dropped from 

floating ice, and hence not in the immediate vicinity of the ice front. 

It is believed that they were laid down in the waters of the Clinton 

stage, while the ice front stood at the moraine 2 to 3 miles north of 

Still River Station.

Examination of the clay under the microscope shows it to be composed of minute angular fragments of various minerals, principally 

quartz and feldspar, ranging from an upper limit of grains 0.5 

millimeter in diameter down to the limit of vision. A sample from 

the New England Brick Co.'s clay bank shows the grains to be very 

uniform in size, only a small percentage being larger than oneseventieth of a millimeter in diameter. Clay taken from the middle 

of two of the exposures showed the following chemical composition:

Analyses of clay from Worcester County, Mass. 

[George Steiger, analyst.]

SiOs. .........................

AljOs..... ........ ............

Fe3O3 .........................

FeO..........................

MgO.. .......................

CaO..........................

NasOa. .......................

1

66.65

16.93

3.05

.84

.96

1.07

2.05

2

57.88

20.68

3.94

2.08

1.60

1.03

1.99

Zj0.................v......

H S0................... ......

HjO+........ ................

Ti02............. .............

C02 .- ........................

1

3.60

1.54

3.03

.80

None.

100.52

2

4.74

1.38

3.63

.88

99.83

1. Famsworth pit, northeast of Lancaster.

2. Brickworks west of Still Eiver Station.

DEPOSITS OF THE AYEB STAGE.

Through most of the distance of 9 miles from Clinton northward 

to Shirley, Nashua River is bordered on the west by terraces having 

an altitude of 260 to 270 feet above the sea. These terraces correspond approximately with the level of the outlet near Ayer. Thus 

it appears that they were formed when the retreat of the ice had 

cleared this outlet and allowed the lake to be drawn down from the 

level of the Clinton stage. Crosby reports that the deposits south 

of Wachusett dam near the river, now largely submerged, were lower 

and much more pitted and discontinuous tlian those farther west. 

Apparently this must also have been true of the filling of the gorge
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 73

at the site of the dam, so that as the lake lowered the course chosen 

by the resulting stream was through the gorge instead of across the 

broad sand plains west of Clinton, beneath which the ancient main 

channel is buried. This was the beginning of the Quaternary 

Nashua River, and the course then chosen has never been abandoned, 

though the removal of the drift filling of the gorge has superimposed 

the stream on the rock divide in the ancient col. With the lowering 

of the water the stream attacked the gravel, sand, and clay so largely 

filling the valley above Clinton and swept the detritus through the 

gorge and into the open lake at the north. This detritus, with that 

brought in by other streams, notably the North Nashua, was spread 

out over the laminated clay in extensive terraces, the distribution of 

which is shown on the map (PL VI). Terraces are well developed 

on both sides of the present flood plain from Clinton to Lancaster 

Commons and South Lancaster. At the latter place a pit in the 

south margin shows poorly assorted and poorly bedded sand and 

gravel, and an exposure near the railroad crossing in the eastern 

part of the village shows cross-bedded sand and gravel dipping to 

the east, as in a delta deposit formed by wash from the North Nashua 

Valley.

Lancaster stands on a till-mantled rock ridge, but the marginal 

slopes are coated with sand and gravel up to about this lake level. 

East of Whittemore Hill, and separated from it by a marshy sag 

and abandoned channel, is an extensive flat terrace which terminates 

at the east in an abrupt 50-foot erosion slope, where the surface 

drops down to the present flood plain. At some places the meandering stream cutting into the foot of this slope exposes the stratified 

sand and fine gravel. Farther north, bordering the base of the 

abrupt 100-foot marginal slope of the high sand plain, is a similar 

terrace, which continues north, to Shirley, a distance of 4 miles, 

varying in width from a quarter of a mile to 1 mile. It is in the 

abrupt east margin of this terrace that the laminated clay is exposed at the New England Brick Co.'s yard, as mentioned above (p. 

70). The surface of this clay is more or less uneven, and a few rods 

south of the brickyard the clay disappears entirely from the section. 

Overlying the clay is 10 to 50 feet of sand and gravel so disposed 

as to give to the terrace a nearly flat surface. This sand and gravel 

is beautifully cross-bedded, as is characteristic of shallow-water deposits along ancient shore lines, but does not show the differentiation 

into top-set, fore-set, and bottom-set beds characteristic of a delta. 

Continued recession of the ice front at length caused the draining 

of that part of the basin within the Quinsigamond quadrangle and 

the further erosion of the deposits in the main and tributary valleys 

and completed the development of the broad flood plain of Nashua 

River north of Clinton.
74 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES. 1923-1924.

GLACIAL LAKE ASSABET.

The history of glacial Lake Assabet began when the ice front had 

melted back to the basin of Whitehall Pond, between 2 and 3 miles 

southwest of Westboro. The water found its first outlet from this 

basin southwestward through the col to Warren Brook. The first 

deposit was the sand and gravel underlying the small flat plain that 

borders the southwest slope of the pond. The swamp south of this 

plain, marking the position of the open water, is probably underlain by the finer silt.

North of the pond is an extensive deposit of stratified sand and 

gravel, of which the higher parts are flat and somewhat pitted with 

kettles. At the north margin it is joined by an esker, described 

above (p. 51), which marks the position of the stream discharging 

from the ice front into the small lake at the time the moraine to 

the west was being formed. When the ice front stood at the moraine west of Westboro the water escaped southwestward through the 

col traversed by the railroad. An excavation near the stream exposes fine laminated sand and clayey sand, including berg-dropped 

boulders.

Continued recession of the ice front opened an outlet to the east, 

through the valley of Sudbury River, traversed by the Boston & 

Albany Railroad at Southville. Throughout most of that part of 

the basin south of the New York,, New Haven & Hartford Railroad 

sand and gravel are spread so as to form a nearly flat plain, of which 

the general altitude is 300 to 320 feet above sea level. This is higher 

than that part of the Sudbury Basin east of Westboro and the outlet 

to the east, so that the deposit may have been completed as 

fluvial outwash. The surface is much pitted and in places has a 

mild morainal aspect. An eskerlike ridge west of Bartlett Pond 

indicates the position of a glacial stream. Northeast of the Worcester 

County Insane Hospital, which stands, on the, hill northeast of 

Chauncey Pond, and north of the New York, New Haven & Hartford Railroad, the general altitude of the gravel plain is about 280 

to 300 feet above sea level. This corresponds to an outlet eastward 

to Reservoir No. 5 by the valley of Stony Brook, now traversed by 

the Wachusett Aqueduct. On this plain and on erosion remnants 

of it stand the villages of Northboro and South Berlin and part of 

West Berlin. Numerous cuts expose the stratified sand and gravel 

and show that most of the pebbles are less than 4 inches in diameter, 

but cobblestones and boulders, some very large, are included. In 

the valley slope at Chapinville fine laminated sand and sandy clay 

are exposed beneath the gravel. Boulders are generally present on 

the surface of the plain, which is also pitted more or less by small 

sags and some larger ice-block depressions. Apparently the depo-
PHYSICAL FEATUEES OF GEE TEAL MASSACHUSETTS. 75

sition took place near the ice front, and some of the abrupt 40 to 

50 foot slopes bordering the streams and ponds appear to represent 

ice contacts. A small terrace with abrupt ice-contact slopes bordering the ridge slope at an altitude of 280 feet 1 mile southwest of 

Hudson indicates that the lake extended thus far down the valley 

while yet discharging through the outlet south of Southboro. Some 

of the sand and gravel in the northern part of the basin may have 

been brought in by the outflow of Lake Nashua, as there was a difference of about 100 feet in the level of the two lakes when they 

were in communication through the south-dike outlet. Most of the 

material, however, probably came directly from the neighboring 

ice front.

North of Chapinville the gravel of this horizon occurs principally 

in narrow terraces on both sides of Assabet River and North Brook. 

At 20 to 60' feet below this level the streams are bordered by a second 

set of terraces, which decline in altitude from 280 feet above sea 

level near Berlin to 220 feet near Hudson. These terraces are remnants of a flood plain developed by erosion of the higher valleys', 

when the melting cleared an outlet by the way of Hudson and the 

col southeastward to Fort Meadow Brook -valley and thence to* the 

lower area on the east. This was the beginning of Assabet River. 

Continued recession of the ice front opened the cols at Gleasondale 

and Rockbottom, located the stream in its present course, and caused 

the development of a bordering flood plain by erosion of the second 

terraces. When the discharge from glacial Lake Nashua through the 

south-dike outlet ceased and the waters no longer reached the Assabet 

basin from the melting ice front, the stream dwindled to its present 

size. The broad plain extending 3^ miles northeastward from 

Hudson has a gentle southward slope, and the upper part of the 

sand and gravel that underlie it must have been deposited as fluviatile outwash from the ice front, though the basin may have 

been flooded when it was first freed from ice. The outlets to the 

east are too low to have permitted submergence of the plain, unless 

they were blocked by an ice dam. Similar gravel deposited partly 

in ponded water and partly in drained basins occupies the valleys 

north of Assabet River.

GLACIAL LAKES AND STEEAMS OF WAKE QUADRANGLE. 

GENERAL RELATIONS.

At numerous places in the Ware quadrangle there are deposits of 

gravel, sand, and laminated silt, whose distribution, character, and 

relations show that they must have been laid down in bodies of 

standing water, yet no lakes or ponds of sufficient extent to afford 

the conditions requisite for their deposition now occupy the valleys
76 CONTKIBUT10NS TO GEOGRAPHY OF UNITED STATES. 1923-1&24.

in which the sediments are found, and the basins are not closed in 

such ways that bodies of water sufficiently large could be retained. 

Hence it is concluded that the present outlets were once blocked by 

barriers, which have since been removed. Such temporary barriers 

would be afforded by the lobate margin of the great ice sheet, as it 

slowly melted backward toward the north, and west across the area, 

with numerous succeeding stages of halt or readvance. The melting 

of the vast accumulation of ice must have afforded an abundance 

of water to flood every depression to the limit of its capacity. Valleys that discharged southward or southeastward provided direct 

avenues of escape for the water, except where the old channels had 

been left blocked by glacial debris. Most of the streams of this 

area, however, prior to the advent of the glacier, drained to the 

Connecticut by way of Chicopee Kiver and its tributaries, as now. 

Some of the smaller basins near the western margin of the plateau 

drained independently to the Connecticut Valley. The conditions 

in the valleys show that the glacial drainage was temporarily blocked 

by the ice on the north or west, enforcing the belief that the retreat 

of the ice was slow and marked by a succession of stages and that 

a great lobe lingered in the valley of the Connecticut after the ice 

had largely disappeared from the upland farther east. The history 

of the several temporary glacial lakes in the west half of the 

quadrangle, together with other features of the glacial drainage 

system, has been described by Emerson. 22 The classification here 

presented on the maps and in the discussion is slightly different from 

that given by him, but the interpretation of prevailing conditions is 

essentially the same, the main difference being that in this discussion the attempt has been made to distinguish somewhat more in 

detail the terminal moraines, outwash plains, deltas, eskers, and 

kames, as indicating the successive positions of the ice front during 

its retreat across the Ware quadrangle.

GLACIAL LAKE NEAR SOUTHBBIDGE.

In the southeastern part of the Ware quadrangle, 2£ miles south 

of Southbridge, in the head of Lebanon Brook valley, beneath 6 to 

18 inches of black soil, is a deposit of dense blue stoneless lacustrine 

clay. At the time of the writer's visit this clay was being used by 

G. I. Wood & Co. for the manufacture of brick. At one place a 

boulder 3 by 6 by 8 feet was seen embedded in the clay just as it had 

been dropped from a mass of floating ice. A narrow ridge of sand 

and gravel 30 feet high at the north side of the small pond marks 

the position of the ice front as it blocked the valley, forming a small 

narrow lake in which the clays were deposited.

22 Emerson, B. K., Geology of old Hampshire County, Mass.: U. S. Geol. Survey Mon. 29, 

1898.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 77 

GLACIAL, LAKES OF BRIMITIELD AND WARKEN.

A terrace of sand and gravel formed where the esker stream discharged from, the ice front into the flooded basin near the State line 

at Mashapaug may be regarded as marking the first stage of Brimfield Lake. The water escaped through a col to the south at 710 feet 

above sea level. After melting back 3 miles to the north along the 

valley the ice front again halted, and the glacial waters deposited, 

in the head of the extended lake, the great terrace or delta of sand 

and gravel on which the village of Holland now stands. This completely -blocked the valley to a height of 720 feet above sea level. 

The abrupt 80-foot north slope marks the contact of the ice front at 

this place. Excavations in the flat top of the deposit show stratified 

sand with cross beds dipping south in the direction of flow. Narrow 

kame terraces border the sides of the valley to the north. About 

this time also the gravel terrace on which stands the village of 

Wales was formed in a small lake. The ice front next retreated 

from Holland to Brimfield and finally to the west side of West and 

Hitchcock mountains, where it blocked the col leading to the 

Quaboag Valley, now traversed by the electric railway. Narrow 

marginal terraces in the northern and western parts of the Brimfield 

basin, at an altitude of 720 feet, indicate either that the ice continued in the valley at Fiskdale after it had left the basin to the west, 

or that the drift dam there was higher than now,"so that the water 

was forced to overflow the terrace at Holland. The broad lacustrine 

plain on which the village of Brimfield stands, which is underlain 

with sand and fine gravel, has about the same altitude as the top of 

the drift dam west of Fiskdale 670 to 680 feet above sea level 

whence it appears that the outlet to the Quinebaug was finally*opened 

over this obstruction. For some time glacial waters came to this lake 

basin from the valleys to the north and west, while similar sand and 

gravel deposits were being f ormed along the moraines in the valleys 

of Taylor and Blodgett Mill brooks, east of West Brimfield, and in 

the basin between Hitchcock and Cedar Swamp mountains.

The clay pit at Massey & Gardner's brickyard at West Brimfield, 

about 600 feet above sea level, in the lower Blodgett Mill Brook 

valley, exposed the following section at the time of the writer's visit:

Section of drift at West Brimfield brickyard.

Feet. 

Buff to brownish sandy till with large boulders on the

surface _____________________________, 10 

Stratified sand and fine gravel in places____________ 0-5 

Dense clay with but few stones (in places lamination may

be distinguished) ; upper 1$ feet weathered brown, dark

blue below __ _________________________ 5-8

Same blue clay, said to have been penetrated to further

depth of ______________________________ 10 

92818° 25 6
78 C'ONTEIBUTIONS TO GEOGEAPHY OP UNITED STATES, 1923-1924.

These deposits indicate that an earlier temporary lake was formed 

when the ice front first entered the valley. As the glacier continued 

to advance southward the silts were buried in till of the ground moraine, and when the valley was again flooded during the deglaciation 

a great thickness of sand was laid upon the till. About 50 feet of 

horizontally stratified sand is exposed in section at the brick kiln, 

and the road from the station eastward to the upland climbs nearly 

300 feet over sand, which mantles the rock slope. The altitude of 

terraces on this deposit indicates that the waters escaped southward 

between the rock slope and the ice front to the col west of Brimfield, 

where they entered the main lake basin.

The high terrace of sand and gravel at an altitude of 700 to 720 

feet above sea level southeast and southwest of Marks Mountain, 

near Warren and West Warren, may have been deposited near the ice 

front in water escaping to Brimfield Lake along the border of the ice. 

Cuts near the cemeteries in the southern part of Warren exposed at 

the north end coarse gravel and farther south 20 to 30 feet of buff 

stratified sand, horizontally bedded in the lower part and with cross 

beds dipping south at the top.

GLACIAL LAKE BKOOKFIELD.

About the time Brimfield Lake reached its greatest extension the 

ice front began te retire from the moraine in the valley south of 

Brookfield and East Brookfield, causing a ponding of water in a 

lake which extended with the further melting of the ice until 

the whole Quaboag Valley was flooded as far west as West Brookfield. Until the valley farther west was sufficiently freed from ice 

this lake discharged to Quinebaug River over the crest of the 

moraine south of Quacumquasit Pond, or through the cols north 

and northeast of Walker Mountain. When visited by the writer 

laminated clays deposited in this lake were exposed at the site of 

the old brickyard at the west side of the north end of Quacumquasit 

Pond, near the bridge at the outlet of this pond, at the brickyards 

at East Brookfield, and at the brickyard north of the electric railroad 1£ miles east of East Brookfield. The exposures at Quacumquasit Pond showed 2 to 5 feet of sand and fine gravel, overlying 

20 feet of gray to brownish clay with laminae one-eighth to onehalf inch thick and thin partings of brown sand, the amount of 

sand decreasing downward.

At the East Brookfield yard of the New England Brick Co. the 

pit exposed, below 7 feet of stratified gravel, laminated stoneless 

blue clay, which is said to have been penetrated to a depth of 35 to 

40 feet before it became too sandy for use. Just south of the railroad station a cut above the track level exposed coarse gravel over 

15 feet of fine stratified sand, and a pit below the track level showed
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 79

10 feet more of finely cross-rippled sand with dips indicating southward wash from the ice front on the north. Extensive sand and 

gravel ten-aces or deltas were formed by wash from adjacent ice 

fronts at East Brookfield, West Brookfield, and the golf links in 

Ellis River valley.

GLACIAL LAKE QUABOAG.

When the Quaboag Valley between West Warren and Palmer was 

cleared of ice it became occupied by a glacial lake, which discharged 

southward over the moraine south of South Monson at an altitude 

of about 620 feet above sea level. This lake, which temporarily 

occupied the valley in Palmer and Monson townships, may for convenience be called glacial Lake Quaboag. It was really formed by 

the flooding of the valley above and below Parksville, but until the 

Monson outlet was opened it stood at a high level and drained eastward through; the col to Brimfield Lake at about 720 feet above 

sea level, so that the deposits then formed are grouped with those 

of that lake. As the ice lowered the waters began to escape southward along the broad shelf on the west slope of East Hill, at 640 

feet above sea level, and thence south across the moraine in Monson 

Valley. Later the lake extended west to Palmer, and deltas or terraces of sand and gravel were formed along the ice fronts on the 

west side of the valley north of West Brimfield, in Kings Brook 

Valley, and southeast of Palmer Center.

As the ice gradually disappeared from the hilly upland between 

Monson Valley and the Wilbraham Mountains, a succession of temporary lakes was formed, as shown by terraces of sand and gravel 

high in the heads of the valleys. These terraces vary in altitude 

according to the position of the cols that afforded outlets for the 

waters. All are in such positions that only ice could have formed 

the retaining dams. None of the cols, however, afforded an outlet 

for glacial Lake Quaboag lower than that of Monson Valley until 

the valley extending southward to Hampden, on the east side of 

the Wilbraham Mountains, was opened. The present divide in this 

valley is at an altitude of 540 feet, or 80 feet lower than that in 

Monson Valley. This valley, however, could not have been the 

outlet for the water for any considerable time, for no deposits are 

found at corresponding levels except those in this valley itself. 

Probably not long after this time the valley traversed by the Boston & Albany Railroad and the electric railway between Palmer 

and North Wilbraham, called by Emerson " Ellis Mills Valley," was 

freed from ice and became the outlet of glacial Lake Quaboag. The 

altitude of the divide in this valley is now about 370 feet. The rock 

shelf at the north end of the Wilbraham Mountains, southeast of 

North Wilbraham, across which the water must first have found 

egress between the ice front and the mountain slope, stands about
80 CONTRIBUTIONS TO GEOGRAPHY OP UNITED STATES, 1923-1924.

390 to 400 feet above sea level, so that when this valley was opened 

there must have been a rapid lowering of the lake about 220 feet 

or more below the Monson level. When this lowering occurred the 

drift dam at Blanchardville, 1-| miles southeast of Palmer, was cut 

through by the waters in the valley above, and the sand and gravel 

were swept into the lower part of the lake. Similar obstructions 

were also cut through near West Brimfield, West Warren, Warren, 

and West Brookfield, the last two perhaps earlier.

The final stage of glacial Lake Quaboag was reached when the 

ice in the valley at Three Rivers disappeared and Chicopee River 

was initiated. The water first broke through between the ice front 

and the hills to the south over the rock shelf traversed by the road 

east of Red Bridge, at about 360 feet above sea level, and not until 

later did it cut the narrow rock gorge now occupied by the river 

below Three Rivers. From North Wilbraham the water probably 

flowed southward for some distance between the east front of the 

Connecticut Valley ice lobe and the west slope of the Wilbraham 

Mountains, until it reached the open lake at the south end of the 

glacier. The lowering of the water soon reduced the lake to a 

stream above West Brimfield. The city of Palmer stands on a fine 

fiat terrace developed at this stage at about 360 feet above the sea. 

Excavations in this terrace show it to be composed of 3 to 5 feet 

of coarse cobblestone gravel over fine gray stratified sand. This 

terrace, now partly eroded by the stream, extends northwestward 

along the north side of the valley a distance of 4 miles from Blanchardville to Four Corners, with slight remnants on the east side of 

Monson Valley opposite Chicopee Mountain, also opposite Palmer, 

and extending southeastward for a mile from Three Rivers. This 

terrace was probably formed principally by erosion of the higher 

terraces of the earlier stage and redeposition of the material. Some 

of its material, however, may have been washed directly from the 

adjacent ice front, which was retreating up the valleys of Ware 

and Swift rivers and Broad and Jabish brooks. A small lake 

held in the valley north of the moraine at Palmer Center discharged 

southwestward through the col at the village to Ellis Mills Valley 

but disappeared when there was opportunity for the water to escape 

around the north end of the hill at Wipples, west of Forest Pond, 

and reach the outlet at Three Rivers. Extending northward from 

Three Rivers and Four Corners to the vicinity of Belchertown is 

a complex deposit formed as the ice front retreated northward. 

Here and there are bits of flat terraces at altitudes corresponding to 

the final stage of Lake Quaboag, indicating that the ponded waters 

extended northward from Three Rivers over the lower tracts as the 

ice disappeared. Interspersed with these, however, are higher terrace 

deposits, which must have been formed by outwash directly from
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 81

the ice, and still other higher areas, marked by gentle undulations 

or knobs and kettles of a terminal moraine. Most of the material 

is stratified sand and gravel, but some is coarse, bouldery, poorly 

assorted drift, just as it was dropped from the ice.

WARE AND SWIFT RIVER DRAINAGE SYSTEMS.

The Ware River valley does not appear to have been blocked by 

the ice in such a way as to form a lake throughout the valley. As 

described above the esker in the valley north of Ware terminates in 

the western part of the village in a terrace or delta on which the 

cemetery stands. This terrace has an altitude of 480 feet above sea 

level, and was probably originally continuous with the gravel terrace at a like altitude south of the river. This may have been formed 

as an alluvial fan or terrace of subaerial outwash by discharge of an 

esker stream from its ice channel, while the glacier still buried the 

valley above Ware; or it may have been formed as an esker delta in 

a small marginal lake, whose outflowing stream was held up along 

the slope of the valley to the southwest by the ice front and escaped 

through the col at Palmer Center, and thence to Lake Quaboag and 

the Ellis Mills outlet. Though the ice front probably retreated 

more rapidly over the eastern part of the quadrangle than in the 

lower and more dissected western part, the trend of the Ware River 

vailey is so nearly southwest that it is doubtful if the upper part of 

this valley was freed from ice before the Chicopee began to cut its 

rock gorge and erode the terraces in the vicinity of Three Rivers. 

The construction of the valley for a mile above the bend at Thorndike suggests that it may have been blocked by a drift dam up to a 

level 400 to 420 feet above the sea. This dam, however, would not 

have flooded the valley above Ware. That it was flooded up to this 

level in front of the ice between Thorndike and Ware appears from 

the well-marked terraces at this altitude. The relations of these 

features, however, indicate that the material composing them was 

washed directly from the adjacent ice front. One of the terraces 

or deltas merges with the south end of the esker, and that in Beaver 

Brook valley terminates at the north in pitted deposits and a wellmarked ice-contact slope. Cuts near the south end of the terrace 

show it to be composed of stratified sand and fine to 3-inch gravel 

over finer laminated gray sand, evidently deposited in the lake. 

Possibly an arm of the glacial lake in Quaboag Valley extended up 

the valley to Ware, while still the ice blocked the outlet at Three 

Rivers and forced the flow through Ellis Mills .Valley.

There is some slight indication that the valley was blocked by 

drift at Gilbertville and that the higher terrace 1 mile to the east 

may have been deposited in ponded water.due to such a dam near 

the bend at the village, or it may be an outwash terrace formed
82 CONTBIBUTIONS TO GEOGKAPHY OF UNITED STATES, 1923-1924.

immediately in front of the ice. The lower terrace bordering this 

at the bend of the river, traversed by the Boston & Albany Railroad, 

is the result of subsequent erosion by the stream.

At Furnace the schoolhouse stands on a terrace 60 to 70 feet above 

the stream at an altitude 660 to 680 feet above sea level. A 30-foot 

cut of the Boston & Albany Railroad through this terrace shows it 

to consist mainly of stratified sand and gravel, though there is 

coarse cobblestone gravel at the north end, where it is somewhat 

pitted. Similar deposits on the opposite side of the valley at New 

Braintree Station indicate that the valley may have been filled clear 

across by wash from the ice front as it lay in Moose Brook valley, 

to the north. It is not evident how the valley could have been 

flooded up to this level, but this deposit may have so obstructed it 

for a time as to hold a lake above it while the ice retreated, and in 

this way may have been deposited the broad terrace now cut through 

by the stream that extends from Wheelwright to Barre Plains and 

the moraine at South Barre. The deposit on the east side at the 

cemetery opposite Wheelwright has the appearance of being a delta 

formed directly in front of the glacier where a stream held by the 

ice against the valley slope discharged into this lake. Above South 

Barre the drift in the valley is principally morainal, with but few 

slight terrace remnants.

High in the valley of Bell Brook, 3 miles northeast of New Braintree, partly eroded terraces of sand and gravel indicate the existence 

of a temporary glacial lake not long before the Ware River valley 

was cleared of ice. A similar deposit occupies the valley of Winiruusset Brook, northwest of New Braintree.

A considerable deposit of sand and gravel 2 to 3 miles east of 

Dana is probably in part morainal and in part formed in a temporary 

lake held up among the hills by the ice front as it continued its retreat northwestward across Worcester County. At one point a cut 

in this deposit exposed 15 feet of sand and fine gravel over 10 feet 

of stratified and finely cross-rippled sand, in which the dip shows the 

wash to have been from north to south.

Extending northward through the towns of Greenwich, Prescott, 

and New Salem is a broad valley drained by the Middle and East 

branches of Swift River. The bottom of this valley is a nearly flat 

plain, 1£ to 2 miles in width, in the midst of which rise several very 

abrupt hills, remnants of the ancient dissected uplands (PI. VIII, A). 

Surrounding these hills and extending from side to side across the 

broad valley, except in some depressions and the shallow inner valleys 

cut by the. streams, is a deposit of stratified sand and gravel laid 

down during the retreat of the ice front northward along the trough. 

The conditions indicate that a, very large amount of water from the 

melting glacier escaped southward through this' valley. Yet it is
PHYSICAL FEATTJEES OP CENTBAL MASSACHUSETTS. 83

not clear that the valley was occupied by a continuous lake. The 

relations suggest rather that the filling is glacio-fluvial and was laid 

down by successive stages from south to north and later partly eroded. 

South of Mount Lizzie is a fine example of lobed sand plain or delta, 

with a pitted top 500 feet above the sea, probably formed when the 

ice front stood at Mount Lizzie with lobes on either side. Against 

this ice front was deposited the higher ten-ace of sand and gravel by 

water flowing southward down Beaver Brook valley. Cuts show 

sand and coarse gravel with pebbles 3 to 12 inches in diameter over 

30 feet or more of stratified sand.

North of Mount Lizzie is the flat sand plain on which Greenwich 

stands. This plain is lower at the south than the terrace south of 

Mount Lizzie, but it rises gradually northward to about the same 

altitude at mount Pomeroy and the hills on the north and east. 

Apparently the valley here was never entirely filled up to the level 

of the plains south of Mount Lizzie, but the flat was formed when 

the lower outlet had been opened by way of Enfield. The plain 

rises gradually northward to the abrupt marginal ice-contact slopes 

at Warner and Sunk ponds. A cut near the bridge three-quarters 

of a mile southwest jof Warner Pond shows stratified and rippled 

sand with gentle southward dip. North of Sunk Pond, in the town 

of Dana, the abrupt knolled and pitted margin gives place to another 

broad, flat plain surrounding small rock hills and sloping gently 

toward the break through the ridge now traversed by the Middle 

Branch of Swift Eiver and the railroad 1£ miles south of North 

Dana. So also from a broad lower tract north of Warner Pond a 

very uniform sandy plain rises gently northward to an altitude of 

540 feet at the north ends of Mount L and Russ Mountain. North 

of these mountains the deposit is more uneven, being broken by 

kettles, ice-block depressions with ponds, and uneven knolled tracts 

interspersed with bits of flat plains in which are cut sharp, narrow 

valleys, suggesting that the disintegrating glacial margin lingered 

here some time and that considerable masses of ice became buried in 

the drift. This part of the deposit is mapped as terminal moraine. 

In like manner were formed the gravel terraces at Dana and 

Nichewaug.

High in the hills of Prescott and New Salem, west of this broad 

valley, are sand, gravel, and laminated silt in three small basins, 

which could have been blocked only by ice dams on the east, and 

similar deposits in open valleys in the west slope required dams on 

the north and west. This conclusion is in consonance with the idea 

that the ice disappeared from the Enfield-New Salem ridge while 

yet lobes projected southward in the valleys on each side. An excavation in the southernmost basin shows stratified sand dipping gently 

northwest, toward the col that must have been the outlet. In the
84 CONTRIBUTIONS TO GEOGKAPHY OF UNITED STATES, 1923-1924.

north basin in New Salem an exposure showed 3 feet of sand and 

gravel over fine laminated sand and clayey sand upon buff till. All 

these deposits are much dissected by erosion.

The West Branch of Swift Kiver has cut its channel in a considerable deposit of moraine, kame-terrace, and outwash sand and 

gravel, which are not readily differentiated, though they were undoubtedly laid down by glacio-fluvial waters as the ice melted on the 

uplands and in the valleys. The material ranges from fine sand to 

coarse morainal gravel. Near the junction with the East Branch, 

southwest of Enfield, are finely developed flat terraces formed after 

the ice withdrew from the moraine west of Quabin Hill.

GLACIAL LAKE PELHAM AND ASSOCIATED LAKES AND WATERCOURSES.

t

The complex character of the deposits extending northward in the 

valleys of Broad and Jabish brooks seems, as noted above, to indicate 

that they are a combination of morainal, outwash, and lacustrine 

sediments formed as the ice front retreated to the vicinity of Belchertown. These deposits of sand and gravel extend northwestward on 

both sides of the Belchertown ridge and terminate in flat terraces at 

the crest of an abrupt slope 200 feet above the valley of Bachelor 

Brook, on the west. It is evident from this relation that the glacial 

front must for some time have remained snugly pressed against this 

slope and the north slope of the Facing Hills and discharged its 

detritus-bearing water southward to the Chicopee.

At 140 feet higher, on the east side of the valley of Jabish Brook 

1£ miles north of Belchertown, is a terrace half a mile in width. A 

sand pit in the abrupt west slope below this terrace exposed gravel 

overlying 20 to 30 feet of well-stratified cross-rippled lacustrine sand, 

showing that the ice front extended northward along this abrupt 

slope. Similar deposits in the heads of several other valleys, in Pelham, Shutesbury, and Leverett, mark the position of other lakes 

held by the ice front high on the west flank of the great Pelham 

ridge. Sand deposits continue northward in the deep, narrow valley 

of Jabish Brook, under flats on both sides of the brook that rise 

rapidly until they reach the valley 1 mile west of Packardsville. 

Here they swing westward and extend across the rock sill to the basin 

southwest of Mount Lincoln, where they merge into a vast accumulation of fine stratified sand deposited in the most southerly of these 

lakes. This deposit is much dissected by sharp ravines, and the 

westward slope drops down very abruptly where_ the retaining ice 

wall stood at the time of the deposition. Clearly the water found an 

outlet, for a time at least, by way of Jabish Brook to the Chicopee. 

Later the water doubtless broke through to the south, being held 

high on the rock slope on the glacial front.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 85

A col at 820 feet above sea level between this basin and that next 

to the north afforded an outlet for glacial Lake Pelham in the 

basin of Amethyst Brook. -The high level of the upper sand of 

this Lake Pelham basin indicates that for a time the close crowding 

of the ice front against the rock slope turned the outflow eastward 

across the rock sill to Jabish Brook, the two lakes thus being continuous. The Lake Pelham outlet, however, whose flat sandy bottom is now deeply notched by streams at the north and south, leads 

directly southward and terminates as a hanging valley at the top 

of a steep slope 300 to 600 feet above Dwight. In a direction a little 

east of south from this valley and 2£ miles distant is the pass between the east end of the Holyoke Range and Pelham Ridge in 

which lie the .Belchertown ponds. These ponds occupy ice-block 

depressions in" a plain underlain by sand and fine gravel, which 

begins just north of the ponds, at the top of an abrupt northwardsloping ice contact nearly 100 feet in height, and declines thence 

gently southward and southwestward through the valley to a broad 

lacustrine plain west of Forge Pond in Granby. In this outwash 

plain Bachelor Brook has since cut its channel. As aptly put by 

Emerson, " The hanging-valley outlets of Lake Pelham above 

Dwight's Station and the pass at the Belchertown ponds face- each 

other like the broken ends of a Roman aqueduct," and it is quite 

probable that they were once connected by a channel in the front 

slope of the glacier when ice south of the Holyoke 'Range had disappeared.

The deposits in Lake Pelham basin are particularly interesting 

and have been described in detail by Emerson.28 Sand is banked on 

the north and east slopes of this basin, well up to and above the 

high level of the outlet to Jabish Brook. On the south and east 

slopes of the basin sand is almost wholly lacking. From these high 

levels the sand extends downward to the till plain, which is traversed 

by the north-south road at 640 to 650 feet above sea level, and there 

spreads out, terminating in a series of lobes or ridges like a lobed 

delta front somewhat dissected by erosion. The till plain represents 

the original bottom of the basin on which the delta sand encroached 

but which it did not cover, as it was swept down from the uplands 

by tributary streams, fed perhaps by the melting of the ice sheet. 

The most interesting part of this deposit is- a great sinuous ridge 

of sand and fine gravel which thrusts its rounded end out upon 

the till plain as one of the lobes of the deposit. The side slope of the 

ridge drops 40 to 60 feet on the south and east to a narrow ravine 

vcut by Amethyst Brook through the sand and 10 or 15 feet into the

'-'Emerson, B. K., Geology of old Hampshire County, Mass.: U. S. Geol. Survey Mon. 29, 

pp. 578-584, 1898.
86 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

till to the rock below. On the north and west sides the slope at its 

terminus drops abruptly 30 to 40 feet to a marshy till flat, and east 

of this flat the slope spreads out somewhat more indefinitely as the 

sand merges into the rest of the deposits on the north. The ridge 

can be traced up the slope to the northeast for about 1,100 yards, then 

turns to the north for about 350 to 450 yards, and becomes a bulky 

hill, 40 to 60 feet high. Swinging back to the northeast, nearly 

parallel to the road, the ridge again becomes narrow and sharp and 

is cut through by a small creek that drains a depression on the north. 

Beyond the notch the deposit merges into the slope north of the 

creek below the road corners, where Amethyst Brook comes down 

from the uplands to the northeast.

There are two interpretations of this feature. Under on© it is 

a true esker, the deposit of a stream that flowed southwestward 

in a sinuous channel in the ice while yet the basin was occupied by 

the glacier, the sand and gravel being let down as a ridge on the 

lake bottom when the ice melted, and then surrounded by sand 

washed into the lake. Under the other interpretation the ridge is 

part of the lobed lake terrace or delta carved into ridge form when 

Amethyst Brook excavated the ravine that closely borders it on the 

south and east, the low marshy tract on the north never having been 

filled. Each interpretation has something in its favor. The material 

of the ridge, like that of the other lobes, is principally sand and fine 

gravel, and the dip of the bedding shows that the wash came from, 

the east or northeast. No fragments of red standstone from the 

Connecticut Valley, to the west, were seen. This direction of wash 

is what would be expected if the ridge is1 part of the delta built 

out into the lake by streams from the upland on the north and east, 

but it is the opposite of what would be expected in a stream flowing 

on the glacier near its margin. When the ice occupied the basin to 

the exclusion of the lake its surface must have been higher on the 

west and southwest; otherwise when the basin was opened it would 

not have retained a lake up to the high level of the upper sand, but 

the water would have continued to flow westward and would have 

escaped into the Connecticut Valley. In other eskers seen by the 

writer in Massachusetts and elsewhere the esker-forming streams 

clearly flowed in or on the ice toward its margin, even when that 

course led them over what are now rising slopes. In the highest 

part of the ridge there may be some morainal deposits, for the 

sand here- is accompanied by considerable coarse cobblestone gravel 

and numerous larger blocks of rock. Sand excavated in the road 

west of Amherst Reservoir is used for brass molding. It is fine, 

clean, white, and beautifully stratified, the beds dipping southward, 

toward the lake outlet.
PHYSICAL FEATtJBES OF CENTRAL MASSACHUSETTS. 87

Farther down the valley to the west a flat terrace sloping gently 

eastward borders the steep rocky south and east slopes of Mount 

Orient and apparently was once continuous southward across the 

portal. The dam thus formed is now deeply notched by the narrow 

gorge of Amethyst Brook. This terrace represents a final stage of 

the lake, when the water was escaping southward between the glacial 

front and the rock slope. Emerson states that excavations for the 

water mains that lead westward from the reservoir down the slope 

of the valley exposed (a) semimorainic beds in the portal over the 

till where the ice front stood, (£>) above and east of these, westwarddipping back-set beds where the sand slumped on the melting of the 

ice retaining wall, and (c) east of these, beautifully cross-bedded 

sand and gravel, whose flow and plunge structure and prevailing 

eastward dip show them to have been deposited by a strong current 

flowing eastward from the ice front into the lake basin.

As the uplands of Shutesbury and Leverett were cleared of ice 

temporary lakes occupied the valleys while they were blocked by 

the glacier on the west, and considerable deposits of sand were left. 

At Dudleyville a narrow terminal moraine lies across the northwest 

side of the basin, showing the position of the ice front when it 

blocked the valley. Terrace sand about Lake Wyola and at Moores 

Corners is the last evidence of the proximity of the ice on the upland 

east of the Connecticut within the Ware quadrangle. When the terrace was being formed in the lake at Moores Corners the wild and 

picturesque gorge known as Rattlesnake Gutter must have been 

occupied by a rushing mountain torrent, plunging down over the 

fallen rocks to the lowland on the west and eroding a narrow valley 

in the sand and the gravel terrace that borders Pond Brook southward to East Leverett. Emerson found deposits of the shore of a 

lake at the level of the col leading from Moores Corners to Rattlesnake Gutter and attributes the erosion of this ravine to the discharge of glacial waters across the col.

MARGINAL DRAINAGE OF THE CONNECTICUT VALLEY GLACIAL LOTCE.

While disappearing from the uplands the ice still continued in the 

Connecticut Valley, projecting southward as a lobe of the glacial 

margin. How long this lobe persisted and how far it extended beyond the main ice front is not known. It seems probable, however, 

that the shrinking of the margin from the valley slope maintained 

such relations as afforded outlet southward between the rock slope 

and glacial margin to the open valley south of the ice lobe. The 

first evidence of the shrinking of the valley lobe within this area 

is the terrace of sand and gravel that borders the west slope of Per-
88 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

kins Mountain, in Somers Township, Conn., over 300 feet above the 

lower parts of the plain on the west. The abrupt west slope of this 

deposit shows where the ice front stood while it held a small body of 

water at this level. The marginal streams resulting from the shrinkage flowed partly over rock, partly on the ice, and laid down considerable deposits of sand and gravel. On the final disappearance of 

the ice these deposits were left as the pitted morainal or kame terraces to which reference has already been made.

It seems improbable that there was at any one time a single continuous stream extending from north to south the whole length of the 

quadrangle between the ice and the rock slope. The stream in this 

position probably widened at the south to a marginal arm of the 

broad lake at the front of the lobe and received tributaries from 

the uplands. As the ice cleared successive valleys on the east more 

northerly tributaries came to the marginal stream, and the widening 

of its channel kept pace with the shortening of the valley lobe. Thus, 

the morainal terrace south of Scantic is probably to be correlated 

with the discharge from the lake in Hampden Valley and its tributaries, one of which, as has been shown, probably received for a time 

the overflow from glacial Lake Quaboag. The next stage resulted 

from the opening of Ellis Mills Valley and the valley of the Chicopee. Here the main contribution went to the open lake, the marginal 

stream that formed the terrace between Scantic and North Wilbraham being insignificant compared with the influx of water which 

these newly opened valleys permitted. The higher deposit of sand 

and gravel bordering the slope northwest of North Wilbraham was 

probably laid down while the moraine southwest of Springfield 

Keservoir was being formed. Gravel in Granby bordering the low 

north and west slopes of the Facing Hills marks the next stage, in 

which most of the waters were reaching the lake by way of Broad 

and Jabish brooks and Chicopee River.

When the ice south of the Holyoke Range had largely or wholly 

disappeared and the lake in Connecticut Valley extended northward 

to Granby, the marginal stream flowed through the pass now occupied by the Belchertown ponds and formed the terrace described 

above (p. 85). The flow through this pass may have continued even 

after the ice had melted over the flat south of Dwight, the stream 

heading perhaps in Lake Pelham and going southward and southeastward through the valley between the low till-covered ridge and 

the high slope on the east. A considerable deposit of sand and 

gravel extends along this course and broadens to a delta north of 

Dwight. Study of the railroad cuts in the sands banked against 

the slope southeast of Dwight convinced Emerson that the stream 

at one stage crossed the depression south of Dwight on the ice and 

flowed through the Belchertown pass. The depressions in the sand
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 89

in the pass, in three of which lie the Belchertown ponds, show that 

considerable masses of ice were buried in the detritus carried by the 

stream. The stream, which was at first high on the slope and drained 

the Pelham lakes in the manner described above (p. 85), later lowered 

to the position north of Dwight. Deposits bordering the lower slope 

north of Amethyst Brook belonged to the same system.

In the valley of Adams Brook, a short distance upstream from the 

Franklin County line, is a narrow gravel flat bordering the stream. 

Crossing the rock ledges it rises and broadens gradually to the 

north and ends north of the pond at an altitude of 450 to 500 feet 

above sea level in an abrupt knolled and pitted slope where the ice 

stood for a time at the north end of Mount Boreas. Farther north the 

East Leverett cemetery stands on the lower terrace of sand and gravel, 

which overlies rocks at 420 feet above sea level. After the sand and 

gravel east of Mount Boreas were deposited the ice seems to have 

cleared the pass to the west and allowed the water flowing southward 

down Pond Brook valley to enter the lake near North Amherst 

before it had time to build the East Leverett terrace up to the level 

of the pass east of Mount Boreas.

t

THE CONNECTICUT VALLEY LAKES.

The deposits from whose study Emerson drew his inference concerning the conditions prevailing in the Connecticut Valley during 

and after the melting of the glacier are mostly outside the quadrangles examined by the present writer. For the full discussion of 

these phenomena reference should be made to Emerson's monograph,24 or for a briefer summary to the Holyoke folio. 25 The 

present discussion of that part of the deposits within the Ware 

quadrangle is based on that of Emerson, whose conclusions are 

in the main accepted. The principal conclusions were that the melting of the thicker ice in the broad valley lagged behind that of the 

sheet extended over the uplands on the east, so that a valley lobe 

extended southward beyond the main glacial front, and that the 

relative altitudes of the land to the north and south and the conditions of outflow of the glacial waters were such that as the south 

front of the lobe retreated the broad valley thus cleared was flooded 

from side to side and the conditions for lacustrine deposition resulted. Emerson wrote:

The stream may have been at first like the body of water which flows from 

under one of the Greenland glaciers; then like the great river Yukon with 

its vast volume and lakelike expansions; and finally like the Rhone, heading 

in a glacier in our smaller New England Alps.

The waters occupied the basin while it was still largely encumbered with the 

remnants of the glacial ice and during all the time of the deposition of the

u Emerson, B. K., U. S. Geol. Survey Mou. 29, pp. 609-749, 1898.

=B Emerson, B. K., U. S. Geol. Survey Geol. Atlas, Holyoke folio (No. 50), 1898.
90 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

central clays floating ice was abundant. The occurrence of arctic plants in 

the upper portion of the clays is in harmony with this state of things, and many 

kettleholes in the high terrace on this edge are in part due to masses of ice 

covered deeply by the sands of unusual floods and remaining for long periods 

in the frozen soil. We may be reasonably sure, also, that no time elapsed 

between the disappearance of the ice and the full occupancy of the valley 

by flood waters. The frontal lobe of ice was buoyed up and flooded away in 

the advancing Avaters.

The ponded condition of the extraglacial waters in the Connecticut 

Valley was probably due in part to differential depression of the 

land, decreasing gradually in amount from north to south, and in 

part to blocking of the valley farther south by morainal outwash 

and lacustrine deposits with which the retreating ice front left the 

valley partly filled. Undoubtedly there was some northward depression of the land, at least near the end of the glacial epoch, whether 

or not the land was so low that the waters in the Connecticut Valley 

constituted an estuary practically at sea level, as certain geologists 

have supposed. <"

The Holyoke Range cut off the Springfield basin and the Deerfield-Toby Range cut off the Montague basin, so that three great areas 

resulted when the valley in Massachusetts was finally cleared of 

ice. These areas were regarded by Emerson as sufficiently broad and 

sufficiently well separated to justify the term lakes, and he named 

them Springfield Lake, Hadley Lake, and Montague Lake. No part 

of the Montague basin lies within the Ware quadrangle. The broad 

lowlands extending southward from the Holyoke Range in Granby 

into Connecticut are a part of the Springfield basin, and the low 

tracts of Amherst Township north of the Holyoke Range belong to 

the Hadley basin.

As the ice front retreated the lake extended northward and successive tributary valleys were opened. The tributaries, as shown above, 

had been restrained in their natural courses by the temporary blocking of their outlets after the basins were cleared of ice, so that the 

waters were forced to find other outlets. In the temporary lakes 

thus formed considerable deposits of assorted drift had been made, 

so that when the natural and lower outlets were opened the rushing waters swept much detritus into the lakes occupying the main 

valley and distributed it far and wide over the valley bottom. The 

broad, flat delta plains in front of the Chicopee River outlet at North 

Wilbraham and of the outlet of Hampden Valley at Scantic have 

altitudes which are now, owing to postglacial reelevation of the 

land, 260 to 265 feet above the sea. It is therefore believed that the 

maximum flooding in Springfield Lake extended up to this horizon, 

the east shore lying along the west border of the morainal terrace 

noted above. Several till-covered sandstone tracts rise above this
PHYSICAL FEATUKES OF CENTRAL MASSACHUSETTS. 91

level in the valley floor, as shown on the map (PI. VI). Surrounding these tracts is an extensive, nearly flat plain, pitted in places 

by shallow kettles and underlain principally by fine assorted drift 

washed out by the streams and in part by coarse gravel dropped 

from the melting ice but not built up to the flood level of the waters.

North of Ludlow the surface rises from a narrow stream terrace 

to a broad, flat plain underlain by stratified sand and gravel and 

pitted with numerous depressions, some of which contain ponds 

or swamps. This plain was either never filled up to the level of the 

plain south of Chicopee River or was subsequently worn down by 

meandering of the river as the flood waters subsided. Under the 

second alternative the buried ice blocks must have persisted until 

the plain emerged, otherwise the pits would have been filled by the 

shifting sand and gravel. In either case the pits constitute evidence 

of the proximity of the ice front at the time of deposition. So also 

the higher sand and gravel plain on which stands Ludlow Center, 

regarded as the highest terrace covered by the lake, is somewhat 

pitted by kettles. These are delta plains resulting from the combined 

outflow of the stream in Chicopee Valley and the melting Connecticut lobe and later somewhat dissected by Chicopee River and minor 

streams. To the north across the ridge, in the southern part of 

Granby, is a similar flat sandy plain about.260 feet above sea level 

at the south margin but rising gently northward to nearly 300 feet 

where it merges into a knolled and pitted morainal tract. This 

moraine or morainal terrace extends southward along the foot of 

the high rock slopes on the east, marking the position of the ice 

front at one stage. Apparently as the melting progressed the 

ice margin gradually swung away from the rock slope until it lay 

nearly east and west across the low tract west of Baggs Mountain, 

its waters meanwhile flowing southwest through the gap between 

the hills to the open lake, the plain thus being in reality a glaciofluvial outwash terrace.

The terrace heading in the pass traversed by the railroad 4 miles 

northwest of Belchertown, 307 feet above sea level at the ponds, 

declines southwestward to Forge Pond, where it merges1 with the 

broad, flat lacustrine plain. This terrace was formed when the 

ice front receded from the great kame terrace north and west of 

Belchertown to the position of the abrupt ice-contact slope north 

of Upper Pond and to the north slope of the Holyoke Range. The 

coarse 6-inch gravel near the ponds gradually changes to 1 and 2 

inch gravel east of Forge Pond and to fine sand spread out over the 

flat plain in Granby. It is thought by Emerson that

The floods of the northern basin continued for a long time to pass across 

the Belchertown notch into the southern basin after the latter was fully 

abandoned by the ice, although (1) the level of the sands in the Belchertown
92 CONTRIBUTIONS TO GEOGBAPHY OP UNITED STATES, 1923-1924.

notch is about 40 feet above the level of the high terrace of the lake to the 

north; and (2) the abundant kettleholes show that the water ceased to pass 

through the notch before the ice had melted out from below the sands spread 

there.

In connection with the two ponds we may call to mind that arctic plants 

are found in the clays of Hadley Lake near their top. This indicates a cold 

climate at an even later time than the one contemplated here, which would 

permit the ice to remain buried almost indefinitely.

With the melting of the ice north of the Holyoke Range the 

flooding of the Hadley basin resulted. This probably began in Amherst Township in the angle south of Dwight, where the ice gave 

place to open water, so that the marginal stream, instead of sweeping its sands and gravels through the Belchertown pass as before, 

dropped them in the water north of Dwight, forming the delta, 

though the clarified water may still for some time have escaped by 

this outlet. Along the lower north slope of the Holyoke Range 

is a poorly marked terrace and sandy deposit. Similar deposits 

border the east side of the valley below the morainal terrace and are 

regarded by Emerson as representing the lake-shore terrace. North 

of East Street these deposits extend on both sides of the valley north 

and northwest to North Amherst. The inner margin of this terrace 

drops, in part with gentle slope and in part abruptly, to the broad 

lake-bottom plain. Fort River has eroded in this plain a lower 

alluvial flat 1,000 to 1,300 feet in maximum width, which extends 

from the railroads to a point about 1 mile north of East Street. 

Cuts in the lake terrace near East Street expose coarse cobblestone 

gravel, and east of the railroads numerous swells and large kettles 

show that here at least the deposit is part of the kame terrace, perhaps submerged on the withdrawal of the ice front, while the buried 

ice blocks yet remained intact. What is regarded as the highest 

lake level in this vicinity is now about 300 feet above the sea, as 

determined by shore phenomena at Amherst and by the level of 

deltas on both sides of the valley.

SUMMARY OF THE PLEISTOCENE OR GLACIAL HISTORY.

A brief summary of the historical phases of the Pleistocene 

geology of the area is presented below. Necessarily the deductions 

drawn from the observed phenomena are of a hypothetical nature. 

The broader questions involved, such as the cause of glaciation, are 

not touched upon in this discussion.

While the ice continued to advance the abrasion of the bedrock 

went on, together with the accumulation of the sheet of till by 

erosion, transportation, and lodgement, the formation of the drumlins, and the deposition of a part at least of the assorted drift of 

the deeper valleys. Of the rates of advance and the duration of the
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 93

occupancy of this area by the ice no adequate measure is available. 

It is known that the period of continental glaciation as a whole was 

very long many times as long as the time which has elapsed since 

the last great ice sheet disappeared. The glacial epoch in New 

England was brought to a close by changes in climatic conditions 

that resulted in an excess of the rate of melting of the ice over the 

rate of its advance, so that the glacial margin was melted slowly 

backward from south to north. As this proceeded the escaping 

waters produced the assorted drift formations which are still so well 

exposed. The abundant boulders scattered over the surface and the 

looser upper part of the till were the final contributions made directly 

by the disintegrating ice, whose last detached remnants lingered long 

buried in the gravel at points where now are the smaller lake basins, 

ponds, and kettleholes.

An attempt has been made to trace the stages by which the retreating ice front traversed the area under discussion from south to 

north. As has already been indicated, no well-marked marginal, 

moraines of any considerable extent have been observed that might 

stand as evidence of repeated stages of increased flow, which held 

the ice margin stationary for long intervals against the assaults of 

the forces of ablation. Only two marginal deposits have been traced 

across ridges intervening between the valleys; the morainal deposits 

in the valleys in places extend almost continuously for several miles 

in directions nearly normal to what must have been the general trend 

of tiie ice front. There are, however, indications such as breaks in 

these deposits, scattered morainal patches, eskers merging at their 

termini with, such deposits or with ice-contact margins of glacial 

sand plains or deltas, and the relations of the deposits of the extinct 

glacial lakes to the requisite retaining ice walls that the ice did not 

disintegrate throughout the area as a wholly stagnant mass, but 

that the retreat of the glacial front was effected by a series of stages, 

with intermittent halts and slight marginal accumulations of drift. 

It does not appear that, except for relatively small buried blocks, the 

valley ice continued as stagnant isolated masses after the uplands 

.had been wholly denuded. The. deposits are very largely such as 

indicate the influx of detritus-bearing waters from a neighboring 

glacial front of considerable extent. Isochronal lines, marking successive positions of the ice front, would therefore show a series of 

reentrants over the uplands alternating with salients projecting 

down the valleys, such as in the scheme presented on Plate VII (in 

pocket). Obviously, such correlations as are attempted can not be 

made without probability of considerable error, and there is even 

question whether they should be included in this discussion. It is 

desirable, however, to make such an analysis of the glacial history

92818° 25 7
94 COFTBIBTJTIONS TO GEOGEAPHY OP UNITED STATES. 1923-1924.

of the region as the phenomena warrant, and for this reason the outline of hypothetical stages is given below.

It should also be stated that the lines of correlation are not such as 

may be recognized on casual visits to various parts of the field. They 

are, indeed, almost wholly inferential and were deduced only after 

detailed mapping of the whole area and careful study of the relations of the deposits as plotted. The grouping of the phenomena 

observed seems to indicate 13 more or less distinct intervals of 

halt of the ice front, accompanied by characteristic deposition, 

alternating with stages of marginal retreat over tracts averaging 

2 to 3 miles in width. The numbers assigned apply only to the 

area under discussion that is, " stage 1 " does not represent the first 

position of halt after the abandonment of the outer moraine on Long 

Island but the first position of halt recognized by the writer north 

of the Massachusetts-Connecticut-Khode Island State line. So far 

as known to the writer such correlations of phenomena in the region 

farther south have not been attempted. The most notable result of 

this correlation is the indication of the gradual development, during 

the deglaciation of the region, of a broad reentrant in the glacial front 

over the Worcester County plateau, while the margin lagged behind 

in the Connecticut Valley and over the lowlands east of Worcester 

County. Nothing more than a tabulation of the phenomena can be 

given in this place. The items are arranged in parallel columns for 

the Ware and Quinsigamond quadrangles in order of their occurrence 

from west to east along the several lines of correlation. It is not 

supposed that the deposits along each line of correlation were exactly 

contemporaneous in their formation. Only their general relations 

are intended to be indicated. To save space altitudes above sea

level are given in the form " at 920 feet."

WAKE QUADRANGLE. 

Stage 1.

Small esker and frontal terrace 3 

miles west of Mashapaug.

Esker frontal terrace and moraine at 

Mashapaug.

Moraine east of Leadmine Mountain, 

3 miles southwest of Sturbridge.

Moraine at reservoir 3 miles southwest 

of Southbridge.

Moraine dam and lacustrine clays at 

brickyard 2$ miles south of Southbridge.

QUINSIGAMOND QUADRANGLE. 

Stage 1.

Moraine and outwash gravels at

Quinebaug. 

Moraine at Webster and kame terraces

about Lake Chaubunagungamaug. 

Moraine at Badluck Pond. 

Gravel at Tasseltop. 

Moraine and eskers north of Chockalog

Pond.

Moraine south of Ironstone. 

Slight moraine at Millville, and gravel

washed down the valley to the south. 

Moraine from East Blackstone to

Woonsocket,
PHYSICAL FEATTJKES OF CENTRAL MASSACHUSETTS. 95

Stage 2.

Lacustrine or outwash gravel terrace 

at Wales; outlet southwest of Stafford, Conn., at 920 feet.

Ice contact and sand plain blocking the 

valley at Holland outlet south at 

720 feet.

Kame terrace extending tlience northeast to East Brimfield.

Drift dam at Fiskdale.

Moraine south of Sturbridge.

Moraine at Westville.

Outwash gravel at Southbridge.

Stage 3.

Small lake in northwestern part of 

Stafford Township, Coon.

Moraine in Mouson Valley south of 

South Monson and outwash gravels 

extending thence south into Connecticut.

Lake beds in basins between Cedar 

Swamp and Hitchcock mountains.

Probably some of the gravels in the 

basin south and southeast of Brimfield.

Moraine dam at Little Alum Pond.

Moraine dam at Long Pond.

Ice contact and gravel terrace at south 

end of Cedar Pond (esker a little 

later).

Moraine and esker at Sturbridge.

Moraine at ponds in Charlton Township.

Stage 2.

Moraines south of Blood, Hayden, and

Pierpont ponds. 

Kame terraces between Oxford and

Webster, ice contacts and sand

plains.

Gravel of Sucker Brook. 

Moraine at West Sutton. 

Moraine and outwash at Manchaug. 

Extensive moraine from Douglas to

East Douglas. 

Margin near Uxbridge and formation

of upper kame terraces beside ice

lobe in valley to south. 

Biver cutting gravels and rock below

Ironstone.

Branch River reversed. 

Slight moraine and wash gravels near

Mendon and South Milford.

Stage 3.

Moraines north and south of Slaters 

Eeservoir.

Moraine north of Howarths.

Oxford outwash plain.

Later, moraine, kame terrace, fosse, 

ice contact, and outwash sand plain 

at North Oxford.

French River cutting moraine to south.

Moraine south of Singletary Pond, 

Clarks Reservoir, and Pleasantdale 

Pond.

Moraine south of Whitins Pond.

Upper terrace gravels in Mumford 

Valley southeast to Uxbridge.

Upper gravel terrace forming in 

Blackstone Valley south to Uxbridge.

Blackstone south of Uxbridge eroding 

first or kame terrace and forming 

second terrace.

Retreat continues; Mumford River 

erodes first terrace and extends second terrace north from Uxbridge, 

and Blackstone River erodes second 

terrace, forming a third at Uxbridge, while depositing the upper 

terrace north of Goods Hill.

Moraine and kame terraces west of 

Miscoe Hill in West River valley. 

(Erosion of terraces may have been 

due to cutting down of the Blackstone Valley at Blackstone and
96 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

Stage 4.

Marginal lake on slope west of Perkins Mountain. 

Lake,, deposits in heads of valleys east

and southeast of Hampden. 

Moraine in valley south of South Monson, waters escaping southward. 

A little later small moraine and esker

in valley west of Mount Hitchcock. 

Col 24 miles west of Brimfield blocked

by ice and gravels washed into Brimfield lake. 

Moraine and outwash gravel in Taylor

Brook valley. 

Moraine northwest and northeast of

Mount Dan.

Moraine south of Quacumquasit Pond. 

Moraine and outwash gravel terrace

at north end of Walker Pond. 

Kame gravels south of Cranberry

Meadow Pond.

Stage 5.

Contraction of Connecticut Valley ice

lobe. 

Kame terrace in Somers Township,

Conn., extending north to Scantic. 

Lake in Hampden Valley with gravel

terraces. 

Kame terrace 2 miles southwest of

Monson. 

Moraine in Monson Valley and esker

formed with outlet through the moraine to the south. 

Ice margin extending north along the

west slope of East Hill, blocking

Quaboag Valley. 

Moraine extending along north side

of valley to West Brimfield and

Woonsocket at an increased rate, 

owing to greater concentration of 

drainage from the ice front as it 

retreated from Uxbridge up the 

three tributary valleys, and also to 

deposition of the load of the waters 

at places increasingly farther north.)

Ice contact and gravel terrace at Hopedale.

Outwash gravels and fine stratified 

sand in Charles River valley at Milford.

Stage 4.

Slight moraine near Charlton Depot. 

Moraine at West Auburn and Auburn. 

Moraine northeast of Singletary Pond

and Millbury. 

Moraine at Wilkinsonville and Saundersville. 

Margin at head of upper terrace at

Fisherville. 

Outwash forming upper terrace south

to Riverdale. 

Waters between Riverdale and Goods

Hill eroding upper terrace and forming second terrace. 

South of Goods Hill eroding second

terrace and forming third terrace. 

Kame terraces and moraine at West

Upton. 

Moraine, ice contact, fosse, an-d lateral

and' frontal terraces at Upton. 

Waters eroding West River channel to

south.

Small esker west of Peppercorn Hill. 

Moraine and eskers east of North

Pond.

Stage 5.

Moraine of South Spencer traceable 

east of Stiles Reservoir.

Moraine south and east of Cedar 

Meadow Pond.

Moraine near Stoneville, and later 

south of Worcester.

Esker at Hadwin Park.

Sand plain north of Stoneville.

Outwash gravels south of Quinsigamond.

Moraine, esker, and outwash gravels 

near Dorothy Pond. .

Moraine at North Grafton.

Earlier, Goddard Pond fosse, ice contact, and sand plain.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 97

later forming drift dam at Blanchardville.

Glacial Lake Quaboag initiated in valley above and below Parksville, with 

outlet eastward through col to Brimfield Lake, at 720 feet or southward 

to Mouson Valley along the broad 

shelf at 640 feet on the west slope 

of East Hill.

Ice contact and lake beds east of West 

Brirnfield.

Moraine in Tufts Brook valley.

Moraines and small . lake terrace 2 

miles southeast of Warren.

Moraine 3 miles southeast of West 

Brookfleld.

Karne terrace bordering slope south 

of Brookfield, thence southeast to 

Quacumquasit Pond and thence 

northeast to East Brookfield.

Brookfield glacial lake initiated in 

front of this ice lobe with outlet 

southward over the moraine at 700 

feet, lacustrine clays deposited at 

Quacumquasit Pond.

Stage 6.

Contraction of Connecticut Valley ice 

lobe.

Formation of kame terrace north of 

Scantic.

Hampden Valley opened, lake drained, 

terraces eroded, and kame terrace 

partly cut away at Scantic.

Margin crossing Wilbraham Mountains 

northeast of Wilbraham.

Glacial waters flowing southward 

through valleys leading to Hampden and depositing gravels in the 

heads of the valleys.

Moraine and frontal terrace 2£ miles 

west of Monson.

Quaboag Valley blocked north of Bald 

Peak at Palmer. Valley clear of ice 

and occupied by glacial Lake Quaboag from Palmer to the drift dam 

west of West Warren, with outlet 

southward through Monson Valley 

crossing morainal dam at 620 feet.

Moraines at Palmer Center, in Kings 

Brook valley and in Quaboag Valley above West Brimfield, with outwash terraces extending south in 

the valleys.

Moraine and esker southwest of Westboro.

Outwash gravels in Miscoe Brook 

valley.

Eskers and moraine at Westboro Reservoir.

Ice contact and sand plain on. southwest side of Whitehall Pond, with 

outlet through col to south.

Moraine at south end of pond.

Later, morainal patches northeast of 

Spencer and west of Worcester.

Stage 6a (not entirely distinct from Cb).

Kame gravel south of Browning Pond.

Kame gravel at Paxtou.

Moraine north of Holden Reservoir.

Moraine and outwash gravels near 

Chaflin, with outlet southeast to 

North Pond.

Outwash gravel south from Summit 

Station.

Ice contact and sand plain at Worcester County farm at north end of 

Lake Quinsigamond.

Ice block in Quinsigamond basin and 

marginal kame terraces.

Gravel east of Temple Hill.

Moraine west of Westboro initiating 

glacial Lake Assabet, in basin to 

south, with outlet through col northeast, of North Grafton.

Moraine southeast of Westboro, witli 

esker and sand plain.

Kame gravel terraces at Hopkinton 

Reservoir.

Stage 6b.

Moraine 1 to 3 miles south of West

Rutland. 

Moraine at Jefferson.
98 CONTRIBUTIONS TO GEOGRAPHY OP UNITED STATES, 1923-1924.

Moraine dam west of West Warren.

Lake terraces south and southeast of 

Marks Mountain at Warren.

Kame terrace on east side of valley at 

Warren.

Quaboag Valley clear of ice east of 

West Brookfield, extending Brookfield glacial lake to this place. Outlet at first south over moraine south 

of Quacumquasit Pond at 700 feet; 

later with further melting of the 

ice water escaped westward down 

the valley, draining the lake.

Ice contact at south end of Wickaboag 

Pond and West Brookfield terrace 

formed.

Moraine and outwash terrace in Ellis 

River valley (a little later).

Moraine and terrace gravel over lacustrine clay at Bast Brookfield.

Margin later retreating over North 

Brookfield hills and up Fivemile 

River valley and depositing kame 

gravels south of Brooks Pond and 

also in Sevenmile River valley.

Stage 7.

Contraction of Connecticut Valley ice

" lobe.

Outlet of glacial Lake Quaboag for a 

time south to Hampden by way of 

Big Brook valley east of Wilbraham. 

Mountains at 540 feet. Later opened 

by way of Ellis Mills Valley across 

the rock shoulder at North Wilbraham at 380 feet; still later shifted 

north to present position of the 

stream.

Formation of kame terrace between 

North Wilbraham and Wilbraham, 

with extension of delta plain in Connecticut Valley.

Upper terrace formed at Butlerville; 

lower terraces cut with lowering of 

the outlet.

Glacial Lake Quaboag lowered and 

Monson outlet abandoned. Lake reduced to a stream above West Brimfield.

Drift dams cut through at Blanchardville, West Brimfield, West Warren, 

Warren, and West Brookfield.

Terraces above and below Palmer 

formed at 360 to 380 feet.

Marginal terrace at about 720 feet on 

northeast slope of Davis Hill; water 

beginning to escape between ice 

front and north slope of Maiden 

Hill.

Later, lake held in Quinapoxet Valley 

by ice from west of Oakdale, and 

valley filled up to about 600 feet by 

a marginal glacial gravel deposit.

Moraine east of Maiden Hill, with 

outlet through col at Summit Station to Great Brook.

Ice contact and high gravel deposit 

(about 580 feet) at head of Great 

Brook and in col traversed by Bos- 

 ton & Maine Railroad.

Ice lobe in Quinsigamond Valley, with 

kame terraces.

Outwash from col north and east of 

Harlow Hill.

Moraine about Bartlett Hill southeast 

to Westboro.

Stage 7.

Position of ice front west of Oakdale

not distinct.

Boylston stage of glacial Lake Nashua 

(A):

Muddy Brook outlet southwest of 

Boylston Center opened over 

drift and buried ice blocks at 

about 480 feet.

Quinapoxet River originated; 

erodes the valley filling and 

forms high delta at Oakdale. 

Boylston terraces formed bordering ice front in Nashua Valley. 

Moraine south of Rocky Pond. 

Northboro stage of glacial Lake Assabet: 

Basin largely filled with sand

and gravel as margin retreats. 

Ice contacts at Northboro, Bartlett Pond, and Chauncey Pond. 

Esker west of Bartlett Pond. 

Outlet north of Westboro at about 

300 feet, thence east through 

Sudbury Valley.

Ice contact and marginal gravel 

at south end of Reservoir No. 

5; outlet south to Cordaville.
PHYSICAL FEATUBES OF CENTRAL MASSACHUSETTS. 99

Gravel terrace in lake north of Palmer 

Center moraine, outlet southwest 

through col at 480 to 500 feet.

Moraine east of Pattaquattic Hill, with 

lake to south.

Kames 2 to 3 miles northeast of Ware.

Moraine and outwash terrace 1$ miles 

southwest of New Braintree.

Gravels northeast of New Braintree.

Moraine north of Brooks Pond.

Stage 8.

Contraction of Connecticut Valley ice 

lobe.

Opening of Chicopee Valley from Three 

Rivers west across the rock shelf at 

360 feet (south of the present 

stream), thence to lake at North 

Wilbraham; slight lowering of lake 

level, and erosion of terrace at 

Palmer to 360 feet. With the shifting of the Chicopee to its present 

course between Three Rivers and 

North Wilbraham and the cutting of 

the rock gorge, glacial Lake Quaboag 

was reduced to a stream and the 

present flood plain was eroded 

through the gravel terrace.

Delta sand and gravel of Chicopee 

River spread widely over the plain 

west and southwest of North Wilbraham.

Kame terrace north of North Wilbraham.

Moraine southwest of Springfield Reservoir.

Deposit of lacustrine outwash and 

moraine gravels in Jabish and Broad 

Brook valleys with the gradual 

northward recession of the ice front.

Kame terrace above Bondville.

Ware River valley blocked by moraine 

above Thorndike, holding a small 

lake above at 400 feet.

Terrace and esker formed by glacial 

stream flowing into this lake 2 miles 

northeast of Bondville.

Later, moraine in Swift River valley 

and esker 1£ miles, below West 

Ware.

Fosse, ice contact, kame terraces, and 

frontal terrace in Beaver Brook 

valley.

Gravels in valley above Ware Center.

Stage 8.

Moraine north of West Rutland. 

Moraine in valley south of Calamint

Hill.

Gravels in Governor Brook valley. 

Moraine across ridge between Governor Brook and Stillwater Valley. 

Moraine, outwash, and esker 2 miles

north of Oak dale.

Moraine and esker west of French 

Hill, with gravel at West Boylston 

deposited in the lake. 

Boylston stage of glacial Lake Nashua 

(B): 

Moraiual terrace and delta northeast of French Hill. 

Esker, ice contacts, and broad 

sand plains east side of Wachusett Reservoir at 460-470 

feet. 

Slight moraine west of Barnes

Hill.

Stony Brook stage of glacial Lake 

Assabet (A) :

Outlet by way of Stony Brook valley and Fayville lowering to 

about 280 feet. 

Ice contacts and gravel plains at

corresponding levels. 

Marginal gravels on west side of 

Reservoir No. 5.
100 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

Kame terrace, fosse, ice contact, 

esker, and frontal terrace in Muddy 

Brook valley at Ware. With 

further melting of this valley lobe, 

extension of the esker northward 

and deposition of moraine south of. 

Muddy Pond and kame terrace to 

the north.

Valley blocked at Gilbertville with 

waters ponded above, and in this 

pond gravel terrace deposited 1 mile 

east of the village.

Morainal deposits thence, northeastward along the valley to Furnace.

Frontal terrace on which stands Furnace schoolhouse formed a little 

later, blocking the valley at 660 to 

670 feet. This held lake above it, 

which extended south up Winimusset Brook valley.

With further melting gravel terrace 

extended northeast up the valley.

Moraine extending along the valley 

from South Barre to Muddy Pond 

2 miles southeast of Coldbrook. 

Outwa's.h southward through the 

valley east of Oakham.

A little earlier, small temporary lakes 

in heads of Bell Brook valley with 

sand and gravel terraces.

Stage 9a.

Contraction of Connecticut Valley ice

lobe. 

Sand and gravel of Ludlow Center

plain deposited in Springfield glacial

lake. 

Ice margin lying about the west and

north slopes of Facing Hills. 

Small esker and pitted gravels south

of Belchertown. 

Pitted gravels and kames. east and

southeast of Belchertown. 

Slight trace of moraine north and

east across the ridge to Swift River

valley. * 

Moraine west of Quabin Hill. 

Fosse, ice contact, and frontal gravel

terrace 1 to 2 miles east of Enfield. 

Moraine 2 miles northwest of Hardwick.

Gravel in Moose Brook valley. 

Moraine in valleys north of South

Barre.

Stage 9.

Moraine from North Rutland to East

Hubbardston. 

Position of ice front west of Bartlett

Hill indistinct. 

Gravel in valley of East Wachusett

Brook.

Moraine across ridge to Justice Brook 

valley. Outwash gravel at West 

Sterling. 

Outwash gravel south from ice contact

at West Waushaccum Pond. 

Clinton stage of glacial Lake Nashua 

(A): 

Ice contact at Cunningham Brook

fosse.

South-dike outlet opened at about 

400 feet and gradually cut down 

to 380-385 feet.

Erosion of higher deposits in the 

valley and development of 400- 

foot and 385-foot terraces. 

Moraine north of Clamshell Pond.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 101

Ice contact and terrace 2 miles north

of Coldbrook. 

Moraine and outwash terrace 2 miles

northeast of Coldbrook.

Stage 9b.

Melting of the ice in south part of 

Granby and gravels washed southwest through Stony Brook valley 

to Springfield glacial lake.

Moraine extending from Baggs Mountain northeast to the ice-contact 

slope west and northwest of Belchertown. Outlet down Broad and 

Jabish Brook valleys.

High lake terrace 1£ miles north of 

Belchertown.

Gravels at Packardville.

Gravel terraces in valleys of Caldwell Brook and west branch of 

Swift River, outlet stream cutting 

through moraine to the south.

Ice contact 2 miles northeast of Enfield, outwash forming terraces at 

Smiths, and Enfield.

Ice contacts southwest and southeast 

of Mount Lizzie; sand plains to 

south with outlet by way of Beaver 

Brook valley.

Ice margin extending northward along 

the slope and blocking the valley 

below Pottapaug Pond; pond occupied by the ice block about which 

was deposited gravel washed from 

the ice front north of Dana.

Moraines and lake terrace deposits 

2 to 3 miles east of Dana.

Ice contact and outwash terrace southeast of Barre.

Moraine 3 miles east of Barre.

Gravel terrace above Barre Falls.

Stage 10.

Ice front at north slope of Holyoke 

Range and ice contact north of Belchertown ponds and rising thence 

northward along the slope east and 

north of Dwight.

Sand and gravel washed southwest 

through Belchertown pass to Springfield Lake in Granby,

Stony Brook stage of glacial Lake 

Assabet (B) :

Deposition of upper gravel near 

Berlin and South Berlin.

Marginal gravel terraces, at about 

280 feet southwest of Hudson.

Slight moraine northwest of Marlboro.

Outwash gravel north of Reservoir No, 5.

Stage 10.

Moraine and esker in. Brigham Pond. 

Moraine in Hubbardston Township. 

Moraine in East Wachusett Brook and

Keyes Brook valley. 

High gravel terrace northeast of

Princeton. 

Slight moraine across ridge and valley

south of East Princeton.
102 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

Sand and gravel deposited in lakes, 

in basins southwest of Mount Lincoln and in Pelham. Outlet east to 

the head of Jabish Brook valley and 

later south over the ice to the Belchertown pass.

Gravels along the west branch of 

Swift River valley. 

Reentrant from Prescott Ridge with 

small lakes held in upland valleys.

Ice contact northwest and northeast of 

Warner Pond and formation of 

Greenwich sand plain to south.

Ice contact at Sunk Pond and deposition of sand and gravel southward to 

Greenwich village. Water possibly 

ponded up to 500 feet by morainal 

dams north of West Ware and south 

of Mount Lizzie.

Outwash gravels at Nichewaug.

Kames 2 miles southeast of Petersham.

Moraine and kame terraces at Williarnsville.

Moraine west of Hubbardston.

Stage 11.

Contraction of ice north of Holyoke 

Range initiating glacial Lake Hadley south of Dwight, with outlet 

through Belchertown pass.

Lower sand and gravel terrace of 

Lake Pelham; outlet south along the 

ice margin to Lake Hadley forming sand and gravel delta north of 

Dwight.

Kame terrace extended north as the 

ice margin lowered on the slope.

Small lakes held in upper valleys in 

Shutesbury by ice on the west.

Ice front in West Branch of Swift 

River valley at Cooleyville.

Reentrant over ridge to the east with 

ice lobe in Middle Branch valley in 

vicinity of Millington. Extensive 

sand plain to south.

Outwash gravel at West Sterling.

Moraine at Clinton Reservoir and 

esker to north; small lake in Bailey 

Brook valley to south, with delta 

and plain.

Moraine south of Pratt Junction, with 

outwash gravel south from Sterling 

Center. Potholes and waterworn 

grooves in surfaces of exposed rock 

ledge at Sterling Center.

Clinton stage of glacial Lake Nashua

(B):

Ice contact on south side of Coachlace Pond, fosse, and formation 

of north-dike sand plain.

Ice margin perhaps occupying the 

gorge southwest of Bolton Station and developing terrace and 

outwash gravels at "Acre" and 

Bolton Station, with waters 

flowing to West Berlin.

Ice contacts and outwash gravel 

near Fryville, with outlet southeast through col at South Bolton.

Moraine at Hudson and south to 

Fort Meadow Pond, with esker. 

Stony Brook stage of glacial Lake 

Assabet (C) :

Small delta sand plain west of 

Hudson and at north side of 

Fort Meadow Pond.

Moraine east of this pond.

Stage 11.

West of Nashua Valley ice margin 

north of Worcester-Marlboro area. 

Deposition of gravels in Wekepeke 

Valley and high sand plain north 

of Whittemore Hill.

Clinton stage of glacial Lake Nashua

(C):

Ice lobe in Nashua Valley south to 

Clinton and perhaps blocking 

North Nashua Valley.

South-dike outlet cut down to about 

360 feet and delta sand plain 

formed southwest of South Lancaster.

Melting of ice lobe in Nashua 

Valley lowers water in North 

Nashua Valley, initiates North 

Nashua River, and causes erosion of gravels and formation of
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 103

Small lake in New Salem Township 

somewhat earlier held up by ice on 

the east.

Gravel 1 mile northwest of Petersham.

Stage 12.

Glacial Lake Hadley extended northward to Mount Boreas.

Ice contact north of Mount Boreas; 

sand and gravel washed southward 

through the valley on the east into 

Lake Hadley east of Amherst.

Lower lake deposits in Roaring Brook 

valley.

Moraine and lacustrine sand at Dudleyville.

Moraine southeast of Lake Wyola.

Later ice disappears from the northwestern part of the Ware quadrangle.

Small moraine at the head of Pond 

Brook.

Sand and gravel terrace formed at 

Moores Corners in a lake held up in 

Sawmill River valley with outlet 

southwestward through Rattlesnake 

Gutter.

second terrace at about 360 feet 

on north side of present channel 

of the stream north of Ballard 

Hill.

Formation of the kame terraces 

extending from Bolton Station 

to Vaughn Hill on east side of 

the ice lobe.

Slight moraines and wash gravel 

in valley northeast of Bolton 

and Hudson.

Margin retreats to moraine north 

of Birch Hill and to Boon Pond; 

fosse, ice contact, and sand plain 

on the southwest.

Gleasondale stage of glacial Lake 

Assabet:

Outlet first through col southeast 

of Hudson to Fort Meadow 

Brook valley at 220-230 feet, 

later through col at Gleasondale.

Assabet River initiated and eroding gravels in the basin.

Crest of Orchard Hill channeled 

and slight esker and delta formed 

as the ice margin lay across the 

hill.

Stage 12.

North half of Quinsigarnond quadrangle almost entirely freed from 

ice.

Clinton stage of glacial Lake Nashua 

(D): 

Outlet still tnrough south-dike

pass at about 360 feet. 

Ice margin near Shirley and depositing moraine northwest of 

Harvard Station (1 to 3 miles 

north of Quinsigamond quadrangle).

Laminated silt west and north 

of Still River station and northeast of Lancaster deposited in 

the lake.

Moraine in Boxboro Township, 

with outwash gravels in Assabet Brook and Heathen Meadow 

Brook valley.

Final stage of glacial Lake Assabet: 

Glacial Lake Assabet drained by 

opening of outlet at Rockbottom. 

Erosion of lower terraces in the 

Assabet basin.
104 CONTKIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

Stage 13.

Ayer stage of glacial Lake Nashua: 

Outlet to northeast opened near 

Ayer at 250-260 feet causes 

rapid lowering of the lake level, 

extension of Nashua River 

through the gorge to a debouchure in the northern part of 

Clinton, resulting in erosion of 

the valley filling above Clinton 

and also in North Nashua and 

Wekepeke valleys. 

Deposits in the lake formed terraces between Clinton and Shirley.

Further recession of the ice front 

opened and lowered outlet to the 

north along the present course of 

Nashua River, drained the lake and 

closed the Pleistocene history of the 

Quinsigamond quadrangle.

RECENT EPOCH.

With the final disappearance of the ice from the several valleys 

the streams were reduced to proportions probably measurably like 

those of to-day and began excavating channels in the glacial debris. 

It appears that a few of the valleys were so blocked by drift that 

new outlets were found through cols, so that former courses were 

abandoned. It is not always possible to determine without test borings, however, that the readjustment had not taken place in preglacial time and that the courses taken after the disappearance of 

the ice had not been adopted earlier. There is some possibility that 

Ellis Mills Valley was the preglacial course of Chicopee River, the 

accumulation of drift causing its abandonment for the course west 

from Three Rivers, where the stream was forced to cut about 80 feet 

in solid rock for three-quarters of a mile. One of the methods used 

by streams in cutting into rock bottoms of their channels is illustrated in Ware, where the river flows over rock ledges between the 

dam and the bridge. At this place several potholes 2 or 3 feet in 

diameter have been excavated by the whirling of pebbles in the hollows of the rock surface. Other excellent examples of potholes and 

waterworn ledges were observed in the rocky bed of Blackstone 

River below the dam near the State line, a short distance west of 

Blackstone (PL XXI, J., B). Excavation of the glacial-lake deposits began with the opening of channels in the upper parts 

of tributary valleys as ponded waters lowered with the retreat of 

the ice and has continued to the present time. The gradients 

of the streams are high, and in many places dams have been con-
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XXI

A.

Ji. 

POTHOLES IN BED OF BLACKSTONE RIVER, MASS.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XXII

A. BARRE FALLS, MASS.

B. WOOLEN MILL, GILBERTVILLE, MASS.
PHYSICAL FEATURES OF CENTRAL MASSACHUSETTS. 105

structed for reservoirs or for the development of water power (PI. 

XXII, A, .Z?). ( The present flood plains are in part due to postglacial excavation and in part to failure of the glacier to fill the 

valley with debris.

Monson Valley contains a great bar of drift which effectually 

prevented its reoccupancy by a large southward-flowing stream. So 

also the valley in Holland was effectually closed to southward drainage, so that the waters now cross rock ledges at East Brimfield and 

escape to the Quinebaug, leaving the great marsh north of Holland 

undrained. A similar condition prevails in Quaboag Valley above 

West Brookfield, the big marsh and ponds being held up by the 

morainal dam south of Quacumquasit Pond.

As conditions became favorable vegetation gained a foothold, a 

new soil was developed on the drift, forests grew, and the accumulation of peat began in the undrained areas. In such peat bogs are 

occasionally found the remains of animals now extinct, which roamed 

the land while yet the northern part of the continent was shrouded 

with ice and for some time after the final disappearance of the ice 

sheet. Franklin P. Eice, of Worcester,26 describes the finding of 

remains of a huge animal in a deposit of peat on the farm of 

William U. Maynard, near the point where the town line crosses the 

road between Shrewsbury and Northboro, about 2 miles northeast of 

Shrewsbury. Specimens of the teeth were submitted to Professors 

Agassiz and Alien, of the Museum of Comparative Zoology, at Cambridge, Mass., and were identified by them as teeth of Mastodon 

americanus [also known as Mammut americanum]. Nine teeth, four 

of them undeveloped, numerous pieces of bone belonging to the 

head, and portions of the tusks had been discovered at the time 

of Rice's publication. The teeth were placed in the Museum of the 

Worcester Natural History Society. Apparently the only Eecent 

factor introduced into this region other than those cited above has 

been the incoming of white men and the consequent deforestation, 

tillage, and stream control.

20 An account of the discovery of a mastodon's rema.ins in. Northboro, Worcester County, 

Mass., Worcester, 1885.

EROSION BY SOLUTION AND FILL.

By WILLIS T. LEE.

INTRODUCTION.

In a region where the rocks are honeycombed surface material 

may find its way into subterranean cavities on a large scale. In 

southeastern New Mexico the formation of caverns by the solution 

of certain kinds of rock and the transfer of surface material to these

16

FIGURE 12. Map of Eddy CoMnty, N. Mex.

caverns have been carried on so extensively that these processes may 

be considered the chief causes of the formation of a broad valley.

Pecos Valley lies between the Guadalupe Mountains on the west, 

which rise to altitudes of nearly 10,000 feet, and the Llano.Estacado 

on the east. (See fig. 12.) It is the broad, shallow depression

107
108 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

through which Pecos River flows, but it is not wholly a valley of 

erosion in the sense in which .the term erosion is generally used.

Streams from the mountains to the west reach the river and erode 

their channels in the ordinary way. Pecos River also carries much 

sand and silt and functions in many ways as a normal stream. But 

no tributary streams were found east of the Pecos in Eddy County, 

and over a wide area not even the dry bed of a temporary stream 

was seen.

ROCKS OF PECOS VALLEY.

N. H. Darton, who has made a comprehensive study of the " Red 

Beds" of New Mexico, has shown that in the eastern part of the 

Pecos Valley the Dockum group, of Triassic age, crops out, but 

through most of its course in Eddy County Pecos River flows over 

rocks of the Permian series. These rocks consist of limestone, 

anhydrite or gypsum, rock salt, and red sandstone and shale. Near 

the surface much of the gypsum and salt have been removed by solution, but at some distance below the surface their full thickness is 

found undisturbed. A well drilled 2 miles south of Carlsbad, after 

penetrating red beds containing much rock salt and gypsum, entered 

a limestone that is locally called the Big lime. The record of this 

well gives the best available data on the thickness of the Big lime 

and beds above it. It is as follows:

Record of well drilled, south of Carlsbad, N. Mex., in sec. 18, T. 22 8., R. 27 E.

[Data furnished by Scott Etter.]

	Feet

Gravel cemented by calcium carbonate, limestone, and sand_ 80

Sandstone and clay, red____________________ 60

Limestone, white _____________ _ 7

Sandstone, gray ___________ 9

Limestone, white _____________ _ _ 17

Red beds ___________________ ___-_ 42

Limestone, white _______________ _,_ _ _ 13

Sandstone, red ________ _ _ 6

Limestone _________________________-_ 19

Red beds ________________________-_____ 62

Gypsum ________ _ __ 23

Red beds ______________ __ 32

Gypsum ... . 15

Rock salt ______ _ 65

Limestone _ 35

Gypsum _ _ _ 49

Rock salt ______ _ 34

Limestone (Big lime) 1,137

Shale, blue - 5

Limestone, black 51

Limestone, black, sandy in some places 69

" Sandy beds " and salt water .. 46 .

Limestone, white _ _ 30

1,906
EROSION BY SOLUTION AND FILL. 109 

SOLUTION CAVITIES. 

SOLUBLE ROCKS.

It is significant that much of the material penetrated in the well 

Avhose record is given above is soluble. According to this record the 

drill went through 1,378 feet of limestone, 87 feet of gypsum, 99 feet 

of rock salt, and 342 feet of insoluble material.

The Big lime is underlain by another group of gypsiferous red 

beds and a still older massive limestone, and much soluble material 

occurs in the rocks younger than those represented in this record. 

As the rocks dip in a general southeasterly direction, a considerable 

thickness of strata east of the river is not represented here. (See 

fig. 13.)

Although there is much soluble material below the Big lime, attention will be confined here to this limestone and the rocks above it. 

Solution cavities occur in great numbers in all the limestones and in 

the beds of gypsum and rock salt. Some of those in the Big lime

NW. se.

Carlsbad Red beds with rock salt and gypsum

^^^^^S^^^^^S^^&S^^^S^

FIGURE 13. Sketch, section from the Valley of Seven Rivers southeastward through 

Carlsbad, N. Mex., showing the relation of the cavernous limestone, locally known as 

the Big lime, to red beds above and below it, which contain, gypsum and rock salt.

are spacious and may be entered and examined. Those in the softer 

material are smaller and have never been entered to any considerable 

distance.

The limestone is hard and dolomitic and forms rugged hills. But 

although it strongly resists erosion, it yields readily to solution. 

Numerous large springs and many extensive deposits of travertine, 

some at flowing springs,- others at springs now extinct, are convincing 

evidences of a general honeycombed condition of the rocks. One of 

best examples of the cavities in the limestone is Carlsbad Cavern. 

Those in the salt and gypsum beds are perhaps best illustrated in the 

sink holes described on page 115.

CARLSBAD CAVERN.

Carlsbad Cavern is about 22 miles southwest of Carlsbad, in sec. 

31, T. 24 S., R. 25 E., and sec. 36, T. 24 S., E. 24 E. It is an 

unusually large cavity, and because of its size and the splendor of its 

onyx decorations it has been made a national monument. It has 

been known since 1901 as a bat cave and a source of guano, but only 

recently have the scenic parts been explored. 

92818° 25 8
110 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

The outlet of this cavern has not been discovered. The only natural opening now known is at the top, where the roof collapsed 

and the rocks fell 246 feet to the floor. Another entrance has been 

constructed by sinking a shaft for the recovery of guano. The main 

passageway was surveyed in the spring of 1923 for about 3 miles, 

by Robert A. Holley, of the General Land Office, and the surface 

was contoured by E. E. Teeter, of the United States Bureau of 

Reclamation, in January, 1924. From these surveys the accompanying map (fig. 14) was constructed. The cavern has been explored 

by James White, of Carlsbad, for some distance beyond the area 

surveyed, but relatively little is yet1 known of its size.

The chambers and passageways as originally formed by solution 

have been partly filled by rocks falling from the walls and ceiling. 

In many places loose aggregations of broken rock lie on the floor. 

The thickness of this debris is not known, but in some places where 

the blocks are large and the spaces between them open, men are said 

to have made their way downward 200 or 300 feet below the present 

floor. In other places the rock fragments are cemented by calcium 

carbonate into resistant masses of limestone breccia.

The walls of the cavern are very irregular, approaching within 

perhaps 100 feet of each other in a few places, then receding in 

lateral chambers many times that width. At the sides of the main 

passageway are many alcoves and rooms, few of which have been 

entered and none of which have been described. In most places the 

walls are rough and jagged where masses of rock now lying on the 

floor have fallen away after they were undermined by solution or 

shaken loose by some earthquake. In other places the walls are 

relatively smooth.

The cavern is a great solution cavity extending diagonally downward to a depth of nearly 1,000 feet. The shape of this cavity has 

been modified by the deposition of calcium carbonate in the several 

forms characteristic of limestone caverns. Stalactites and stalagmites, popularly known as " dripstone," are numerous and are remarkable for size and variety of form, as shown by Plates XXIV, 

E; XXV, A; XXVI, E; XXVII, E. Deposits of calcium carbonate 

have also accumulated against the walls in many places where 

water trickles from the rock. Here and there these accumulations 

assume forms that closely resemble masses of ice, and some of the 

" cascades frozen in stone " are large and impressive. To distinguish 

this material from that deposited by dripping water, it has been 

called " flowstone."

Little can be said of the size of the chambers and passageways in 

this cavern, as few measurements have yet been made. Some of the 

chambers are several hundred feet wide and have ceilings so high 

that torches fail to illuminate them. The largest compartment yet
EROSION BY SOLUTION ANI> FILL.

FIGURE 14. Map and profiles of Carlsbad Cavern, National Monument, N. Mex., showing 

the alinement of the surveyed parts of the cavern and its relation to the ground Burface. Prom surveys made by Robert A. Holley and E>. EX Teeter.
112 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1&24.

discovered is appropriately called the Big Boom. Holley's survey 

shows that this room is more than half a mile in length, and it 

probably averages more than 200. feet in width. The floor lies 

about 700 feet below the surface of the ground, and apparently the 

rock cover is little more than a shell. This room is as remarkable 

for ornate decoration as it is for size. Dripstone decorations occur 

in infinite variety of size and shape. (See PL XXIV, B.) There 

are thousands of pendants, some so delicate and slender that they 

break under the slightest pressure; some so massive that the observer 

marvels that so enormous a weight can be sustained. (See PL 

XXIII, B.} The stalagmites are less varied. One group in which 

the forms are usually tall and graceful has been called the totem 

poles. Some of these only a few feet in diameter rise to a height 

of 40 feet.

Many of the stalagmites in this part of the cavern have blunt, 

rounded ends (see PI. XXV, A] and are composed of material that 

seems to differ from that of the surrounding forms. They appear 

dark colored and contrast sharply with other forms in having a 

smooth surface in place of the chalky-white frost-work surface which 

is more common. Some of the stalagmites are of unusual dimensions. 

The twin domes (see PL XXVI, B) are said to be more than 100 

feet high and to measure more than 200 feet across the base. This 

base is a mammoth dark-green mound having a wet, slippery surface. The color of some of these forms suggests the presence of 

algae or other forms of plant life. It remains to be determined if 

algae can live in the darkness of the cavern. Fungi might thrive 

in the darkness and may possibly have had something to do with 

the deposition of the calcium carbonate.

Some of the most interesting features on the floor of the cavern 

are grouped about the basins of extinct springs. Some of the basins 

are 10 feet or more in depth and perhaps 50 feet across. They are 

lined with an unknown thickness of onyx and in their profuse 

decoration closely resemble some of the hot springs in Yellowstone 

National Park. If the Biscuit Spring of the Yellowstone were 

drained, leaving the surrounding crust of mineral matter undisturbed, it would resemble one of the basins in Carlsbad Cavern. 

(See PL XXV, B.) .

In many places stalactites and stalagmites have joined to form 

columns of impressive dimensions. (See Pis. XXIV, B, and 

XXVI, A.) No measurements of these columns have been made, 

but they are very high, very large, and very astonishing.

Near the end of the Big Room is a small opening in the floor, 

which leads to lower chambers that lie below the floor. The bottoms 

of these chambers are below the level of the plain, nearly 1,000 feet 

below the entrance to the cavern, and they probably drain through
U. S. GEOLOGICAL SURVEY TOO PLATE XXIII

A. YEITSO'S PILLAR, CARLSBAD CAVERN, N. MEX.

Showing the side of the great chamber formed by solution and later decorated by the deposition 

of calcium carbonate. Copyrighted photograph by Ray V. Davis.

B. A PARTITION OF ONYX, CARLSBAD CAVERN.

A wall in one of the chambers known as Shinav's Wigwam (from Shinav, a mythical deity of 

the Navajo Indians). The stalactites have grown together laterally into a solid curtainlike mass. Photograph by W. T. Lee.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XXIV

A. STALACTITES, CARLSBAD CAVERN.

Hanging from the ceiling in the great chamber called Shinav's Wigwam. Photograph by

W. T. Lee.

B. HATTIN'S DOME AND THE TEMPLE OF THE SUN, CARLSBAD CAVERN.

One of the spectacular scenes combining many of the characteristic features of the cavern, 

such as stalactites, stalagmites, columns, and monuments. Photograph by Ray V. Davis.
TT. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XXV

A. STALAGMITES AND COLUMN, CARLSBAD CAVERN.

The column shows the decoration characteristic of the columns in this cavern. The large 

stalactites are relatively smooth. Because of the resemblance of this material to ice, 

it is popularly known as flowstone. The stalagmites in the foreground are composed 

partly of coralline material and partly of smooth dripstone. Photograph by Ray V. 

Davis-

£. SPRING DEPOSITS, CARLSBAD CAVERN.

Many basins, some of which are now dry, are ornately decorated with mineral matter 

deposited in a variety of forma. Photograph by W. T. Lee.
tJ. S. GEOLOGICAL SURVEY BULLETIN TfiO PLATE XXVI

A. PILLARS OF ONYX, CARLSBAD CAVERN.

Some of the pillars are relatively smooth, such as that shown at the left, but many of them 

are composed of tiny overflow fountains beneath which streamers trail away like hanging 

drapery Photograph by W. T. Leo.

B. TWIN DOMES, CARLSBAD CAVERN.

Shows also one of the large pillars having relatively slight connection with the ceiling, 

where stalactites and utalagmites have joined to form a column. Photograph by 

W. T. Lee. .
U. S. GEOLOGICAL SURVEY BULLETIN TOO PLATE XXVII

A. CORALLINE STALAGMITES, CARLSBAD CAVERN.

In some places the deposit is irregular, resembling coral growth. In other places, as at the 

tops of these stalagmites, the material is relatively smooth and clear. Photograph by 

\V. T. Lee.

IS. A CHARACTERISTIC SCENE IN CARLSBAD CAVERN.

Shows a variety and wealth of columns, stalactites, and stalagmites. Photograph by

Ray V. Davis.
U. S. GEOLOGICAL SURVEY BUT.LETIM 700 PLATE XXVIII

SINK HOLES ON LIVINGSTON RANCH, ABOUT 20 MILES SOUTHEAST OF 

CARLSBAD, N. MEX.

A, Formed in August, 1918, when a cavern collapsed, leaving an opening about 75 feet 

across and 60 feet deep; -R, formed by the collapse of a cavern in gypsum lying near the 

surface. Photographs by W. T. Lee.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XXIX

- ^^':"<&**.& 

' ' .^>*fc\3

-:',. l^C^^W^.;^! 

SffZfc- S *\ :.(*?&&.'*

A. PECOS RI\I:K AT RED BLUFF DAM SITE, N. MEX.

Showing dolomitic limestone resting on gypsum. The limestone dips steeply to the east 

(left) because of slumping due to the removal by solution of some of the gypsum. Photograph by W. T. Lee.

B. A PLAYA.

Small temporary lake formed by the choking of a sink hole and the silting of a depression 

formed by the settling of material near the surface. Photograph by United States 

Bureau of Reclamation.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XXX

A. ENTRANCE TO CAKLSBAI) CAVERN.

The limestone of the cavern roof here fell to the floor, a vertical distance of 246 feet. 

Photograph by W. T. Lee.

IS. TRAVERTINE IN LAST CHANCE CANYON, NEAR QUEEN, N. MEX.

The bed of limestone at the right was thickly covered wilb calcium carbonate deposited from 

spring water. The water no longer flows over the travertine, and the part showing 

aoove the century plant has begun to break down. Photograph by W. T. Lee.
EROSION BY SOLUTION AND FILL. 113

one of the springs about 3 miles from the foot of the mountains 

perhaps Rattlesnake Spring, described on page 120.

The myriads of cylindrical sharp-pointed stalactites give place 

here and there in the cavern to broad thin sheets. But the great 

variety of curiosities is found on the floor, where they can be examined in detail. There are vast numbers of stalagmites 1 to 5 feet 

high. (See Pis. XXIV, B, and XXV, A.) In some places these 

stand so close together that it is difficult to walk among them. Most 

of these low stalagmites have a rough granular surface of a general 

warty appearance, somewhat resembling coral. (See PI. XXVII, 

A.) Some of the excrescences have grown into short stumpy 

branches, giving each stalagmite a bristling appearance. In places 

the excrescent forms are surmounted by masses of smooth clear onyx, 

which give them a startling resemblance to bald-headed men in ragged clothing. Many of these smooth-topped stalagmites have at the 

top a splash cup or small receptacle containing water; others may 

be called frozen fountains, for the splash cup is filled with clear 

onyx.

DEPTH OF CAVERNOUS CONDITION.

It is debatable how far below the water table a cavernous condition may develop. The entire floAv of Pecos River goes underground near McMillan and reappears farther downstream. This 

can scarcely be a near-surface phenomenon. Furthermore, the depth 

to which a cavernous condition of the limestone sufficient for artesian 

flow extends is indicated by the wells in the Roswell artesian basin, 

which lies just north of the Carlsbad area. Fisher 1 shows that 

artesian water is derived from a porous limestone, the depth of 

which in 20 wells ranges from 535 to 976 feet below the surface. This 

limestone is older than the Big lime of the present paper that is, it 

lies below the lower group of red beds shown in Figure 13 but it 

has similar characteristics. It seems clear, therefore, that a porous 

condition or the presence of incipient caverns may be expected in 

the Big lime to a depth of several hundred feet below the surface.

LIMESTONE BRECCIA.

Limestone composed of angular fragments cemented together with 

calcium carbonate occurs in many places in Pecos Valley. Some of 

this breccia was formed at the surface, but probably much of it was 

formed in caverns and resembles the very coarse masses now forming in Carlsbad Cavern. These cavern breccias are free from foreign 

matter and may be distinguished by careful examination from those 

formed at the surface, which contain fragments of rock brought 

from a distance.

1 Fisher, C. A., Preliminary report on the geology and underground waters of the Roswell artesian area, N. Mex.: U. S. Geol. Survey Water-Supply Paper 158, 1900,
114 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1&23-1924.

The fragments in the limestone breccias are held together by 

material resembling cement. In some places the cementing is so perfect that the rock will break through the fragments rather than 

through the cement*, The origin of this material is illustrated in 

Carlsbad Cavern. Water percolating through the limestone takes 

calcium carbonate into solution, as shown by the analyses of water 

on page 120. Under favorable conditions this mineral matter is released and deposited. The great quantities of onyx in the cavern 

afford an impressive illustration of the magnitude of this action. 

Moreover, the quantity of material that has accumulated among the 

fallen blocks and has cemented them into solid masses must be many 

times greater than that now visible. Probably similar action is 

going on in a great number of caverns and in the numerous smaller 

cavities of the honeycombed rocks.

The quantity of material dissolved and redeposited is illustrated 

also by the beds of travertine found near the foothills west of Pecos 

River. In many places the plain is covered to some' unknown depth 

with calcium carbonate deposited from spring water. Some of the 

springs are still active; others are extinct. In several of the canyons 

great deposits of travertine are found, as that in Last Chance 

Canyon, shown in Plate XXX, B. This deposit is now disintegrating, as the spring from which it issued is extinct, but other deposits 

near by are still growing.

As the quantity of calcium carbonate taken into solution and 

either carried away or redeposited is large, and as the direction of 

transfer of material by solution is always downward, erosion by 

solution in this region must, in time, accomplish large results, even 

though much of the material may be redeposited rather than carried 

completely away.

CAVITIES IN SALT AND GYPSUM.

In many places in Pecos Valley there are holes in the ground 

some open, others choked or partly closed with fragmental material. 

Some of the most conspicuous of the sink holes were found on the 

Livingston ranch, about 20 miles southeast of Carlsbad, where the 

underlying rocks contain gypsum and rock salt. One hole observed 

on this ranch (see PI. XXVIII, A) °is circular in outline, about 

75 feet across, and 60 feet deep. This hole was formed during a 

storm in August, 1918. Some of the material that dropped into 

the cavern below still rests in a conical mound on the cavern floor. 

At another sink hole on this ranch the rocks of the cavern roof are 

only a few feet thick. (See PL XXVIII, B.) The sinks are so 

numerous that the ranchmen fence them to prevent the cowboys from 

riding into them while running stock.
EROSION BY SOLTTTIO'lSr AND FILL. 115

The cavernous condition of the rocks near the surface on the 

Livingston ranch is emphasized by the difficulty in finding water 

there. More than 50 holes have been put down on this ranch, but 

water has been found on the average in only 1 in 10. The ground 

water seems to be confined to streams in underground passageways. 

One well may yield water, while another within a few feet of it is 

dry.

Near the ranch house, in sees. 9 and 10, T. 22 S., K. 30 E., 12 wells 

were drilled, but water was found in only one. The following 

record of these wells was obtained, but their exact location can not 

be indicated. No. 1 supplies 2,000 cattle; No. 2 is a seep; the others 

are dry.

Record of wells on Livingston ranch.

No. 1 (productive well).. .....

No. 2.........................

No. 3.. .......................

No. 4.........................

No. 6................. .....

Distance 

from 

No. 1 

(feet).

60

120

125

175

Depth 

(feet).

66

66

80

237

90

No. 6...... ...................

No.7...... ...................

No. 8.........................

Nos. 9-12.....................

Distance 

from 

No. 1 

(foet).

±100

±300

600

(a\

Depth 

(feet).

(?)

(?)

95

±100

0 Less than a quarter of a mile.

Similar conditions were encountered in several parts of this ranch. 

Mr. Livingston states that in some places where one well had been 

obtained water was found in another well near by, though not in- 

.variably in the second one drilled, but that in other places search was 

abandoned after 10 or 12 holes had been drilled.

Sink holes are numerous wherever beds of salt and gypsum lie 

near the surface. Many of these were observed north of Carlsbad, 

near the McMillan reservoir. Here the gypsum is exposed in many 

places and appears to occur in detached masses, terminating abruptly 

where parts of the bed have been dissolved out and replaced by insoluble material. This solution of the gypsum has resulted in an 

unusual number of sink holes near the river. Those in the bed of 

the McMillan reservoir are so large and numerous that the reservoir 

has seldom been filled, the entire flow of the river, even at times of 

moderate flood, going into the sink holes. Farther south, in the basin 

of the proposed reservoir No. 3, similar holes were found.

Sink holes >were noted in several stages of development ranging 

from open, newly formed holes, through holes showing varying degrees of fill, to sinks completely chpked and silted over, like the one 

shown in Plate XXIX, B. In some places the collapse of the caverns is progressive. When 'a hole becomes choked a new one opens
116 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

near by. This progressive collapse of the surface has resulted in 

many large basins. The road between Carlsbad and Lovington 

passes through a large sink called Eed Lake. Except for small 

pools of water held in thickly silted depressions, Red Lake contains 

water for only short periods after storms. It is said that this depression is the natural receptacle for the drainage from several townships, but relatively little of the storm water reaches it, and that 

little soon disappears underground.

A similar depression about 5 miles east of Loving is known as 

Alkali Flat. The lowest part of this depression contains a body of 

salt water. Another of similar nature lies west of the river near 

Malaga. These sunken areas, which do not have surface drainage 

to the river 'and which are clearly due to the collapse of caverns 

formed by the removal of soluble rocks, suggest that the several 

basins through which the river flows were formed in the same way. 

In one such basin on Hondo Eiver near Roswell a futile attempt 

was made to construct a storage reservoir. Several basins of similar 

nature have been investigated as reservoir sites, but construction has 

been delayed because of the unfavorable conditions, although one 

small reservoir at Avalon has proved successful.

DRAINAGE.

In southeastern New Mexico the Pecos receives; little surface drainage from the east. The storm water forms sheet floods and short 

temporary streams, but these soon disappear underground and find 

their way through the cavernous rocks, naturally seeking the lowest 

outlet. Some of the water finds its way into the undrained lakes, 

such as that in Alkali Flat and the one near Malaga, but the chief 

outlet is to the channel of the Pecos.

Although Pecos River flows through a semiarid country and receives little surface drainage during dry seasons, it is a stream of 

considerable size at all times. One spring at Carlsbad discharges 

into the river 5y2 second-feet of water. Blue Spring, 30 miles 

southwest of this town, discharges 18 second-feet. Records of two 

gaging stations near Carlsbad, 2y2 miles apart, show that 80 secondfeet of water enters the river in this distance. South of the McMillan 

reservoir underground water, some of which is derived from this 

reservoir, returns to the stream in large quantities.

This entrance of water into cavernous rocks in Pecos Valley 

and its return to the surface at some distant place has been known 

for many years. G. H. Russell 2 has described the disappearance

2 Freeman, W. B., and Mathers, J. G., Surface water supply of the United States, 1910, 

pt. 8: U. S. Geol. Survey Water-Supply Paper 288, pp. 109-112, 1911.
EROSION BY SOLUTION AND FILL. 117

of the entire river into cavernous rocks near Santa Rosa and its 

return to the surface a few miles farther downstream. He further 

states that

A chain of sinks, or so-called dry lakes, extends from a point near the place 

of sinking to the flowing lakes of Santa Rosa. Some of these sinks are smooth 

depressions covering several acres; others are holes 50 feet in diameter. The 

latest formed depressions have vertical sides and range in depth from a few 

feet to a hundred feet or more. Erosion gradually rounds off the edges and 

fills the middle until there remains only a pot-shaped depression. Some of 

these depressions have been formed since the settlement of the country. It is 

said that a man living upon the mesa found one morning in front of his house 

a hole 60 feet in diameter and about 150 feet deep. A story is also told of a 

suddenly formed depression that filled with water and was claimed by two 

men. The controversy was taken to court, but before a decision was rendered 

the water disappeared, leaving only a dry hole.

The lakes near Santa Rosa are 200 to 300 feet in diameter, and some of them 

are reported to have been sounded to a depth of about 250 feet. They receive 

no surface drainage, but each yields a constant overflow of several second-feet. 

The surface of these lakes is only a few feet above the river and is 300 to 400 

feet below the level of the sink holes on the mesa. The water is heavily 

charged with gypsum and gives off a " gyppy " odor.

These sinks afford conclusive evidence of solution in the gypsiferous beds, 

and the course of their succession, leading from the place where the river sinks 

to a point where the water reappears in the lakes, forms strong presumptive 

evidence that underground passages are followed by the water between those 

points. The incident mentioned above, in which a depression formed by a 

cave-in filled with water, also affords evidence of underground passage. In 

this case it is reasonable to conclude that the cave-in choked some subterranean 

watercourse, thus forcing the water up into the depression until it acquired 

sufficient head to reopen its channel, when the pent-up water in the depression 

sunk away.

REMOVAL OF DEBRIS FROM SURFACE.

Great quantities of surface material disappear into the caverns. 

In the one shown in Plate XXVIII, J., nearly 30,000 cubic yards 

disappeared in a single night. Large quantities of sand and silt are 

washed into the caverns by storm waters. Wind is continually drifting dust and sand into them. In brief, the .surface material, which 

in most other regions is removed by surface drainage, here finds its 

way into subterranean caverns, where it lodges in spaces vacated by 

soluble material.

Some of the material that enters a cavern lodges near the opening. At the bottom of the hole pictured in Plate XXVIII, A, a 

cone may be seen resting on the floor, as illustrated at & in Figure 15. 

In other holes no open space is seen between the sides of the opening 

and the debris that chokes it. In still others the hole is filled and 

the surface above it is silted over, as illustrated in Plate XXIX, A.

The process of the transfer of surface material to subterranean 

caverns is not difficult to visualize, given a honeycombed condition
118 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

of the rocks, as illustrated in Figure 15. In some places the overhanging material will fall, as illustrated at ~b and c, or slump, as at 

d and e. If such a slumping extends to the surface, the condition 

illustrated in Plate XXIX, A, may result. At the locality shown a 

limestone block has slumped because of the removal of gypsum from 

beneath it. The winds and floods bear surface material into the 

openings. The coarser matter lodges near the entrance; the finer is 

distributed more widely by the underground streams. A fall from 

the roof of a cavern may choke a passageway, as illustrated at d, 

Figure 15, or the cavern may gradually fill until it is complete^ 

sealed up, as at <?, and made water-tight so that new openings are 

sought, as at / and «, which in turn become filled in time, producing

FIGURE 15. Sketch, section illustrating the formation of solution, caverns in strata containing gypsum and rock salt. The caverns are formed in, the gypsum and rock salt, 

and connecting channels are cut through the limestone and other strata. At the bottom of opening a is some of the material 6 which fell from the roof; at c material 

whichi fell within, the cavern.; at d and o massesi of hard rock which, slumped when 

support was removed from one side; at f a small choked opening; at g an old sealed 

opening.

the condition illustrated in Figure 16, where undisturbed strata end 

abruptly against detrital matter, as at #, or disturbed strata lie in an 

unnatural position (5) surrounded by fragmental material (c) with 

caverns (d) filled and sealed.

In places where the soluble material has been removed more rapidly than at neighboring localities, or where the filling has not kept 

pace with the removal of soluble matter, the collapse of the rocks 

near the surface has formed basins, such as Alkali Flat and the lake 

basin near Malaga. It is probable also that the basins along the 

streams in some of which attempts have been made to store water for 

irrigation were formed in this way. These attempts are .generally 

regarded as failures. The Hondo reservoir,3 situated in such a basin, 

was abandoned after leaks amounting to 200 cubic feet a second 

developed. The skill of the engineers has succeeded in making the 

McMillan reservoir useful as a regulator of flood waters, compelling

3 Davis, A. P., and Wilson, H. M.r Irrigation engineering, p. 350, New York, John 

Wiley & Sous, 1919.
119

.the leaks, which they have not been able to stop, to serve as retarders 

of flow.

Some idea of the rate at which this lowering of the surface goes 

on may be gained from measurements of the volume of flow in Pecos 

River and the quantity of mineral matter which it carries. Near 

Carlsbad the/ water contains 2,680 parts of mineral matter per million 

parts of water, and it has been computed 4 that on the average this 

river removes each year 103 tons of mineral matter for each square 

mile of its drainage basin. Farther south, near the Texas line, where 

the river carries the water that has returned from the caverns near 

Carlsbad, the flow averages more than 500 second-feet and the water 

contains more than 4,000 parts of mineral matter per million parts

EXPLANATION

Debris Shale Sandstone Gypsum Limestorte' Rock salt

FIGURE 16. Sketch section illustrating the filling of solution channels and the fonnation 

of surface depressions by the enlargement and collapse of caverns. Solution lias proceeded until the material near the surface is- a jumbled mass, giving place laterally to 

undisturbed strata.

of water. As the river receives little water from surface tributaries 

in this part of its course, the mineral matter carried across the/ TexasNew Mexico line, amounting annually to more than 150 tons to the 

square mile, comes chiefly from underground sources. Furthermore, 

much of the area included in this computation is little affected by 

solution, while from other parts of the area the soluble matter is removed rapidly.

KINDS OF WATER.

The waters of Pecos Valley are so diverse and the amount of salinity they contain varies so widely that even the average represented by the river water may be misleading. The water from some 

of the wells, and springs is so saline as to be a brine, which can not 

be used for stock. Some of the water is supposed to be poisonous, 

but this may be due only to the abundance of gypsum it contains in 

solution. Five samples of water from this valley were sent to the

4 Dole, R. B., and Stabler, Herman, Conservation, of water resources: U. S. Geol. Survey 

Water-Supply Paper 234, p. 86, 1909.
120 CONTRIBUTIONS TO GEOGBAPHY OP UNITED STATES, 1923-1624.

United States Geological Survey and analyzed. The results are given, 

in the following table:

Analyses of water from Pecos Valley, N. Hex. 

[Analyzed by C. S. Howard. Parts per million.]

Silica (SiOs) - - -. . . 

Iron (Fe)_, _--___...._..-... .......... .. ..

Calcium(Ca). -...... . .- . - -

Carbonate radicle (COs) _______________ -

Sulphate radicle (SO*) ______ .. .................

Chloride radicle (Cl) ---_-.-----_--.---------------.--

Total dissolved solids at 180° C.. ........ .............

Date of collection (1923)-....... ............. .........

1

14

Trace.

96

29

24

0

277

108

4.0

.89

408

Nov.12

2

14

Trace.

246

37

41

0

226

551

7.0

2.0

1,046

Nov. 12

3

19

.08

460

50

38

0

215

1,104

6.0

1.6

1,897

Nov. 12

4

757

209

« 1, 160

0

134

2, 295

1,965

6,944

Nov. 15

5

0.6

762

2,354

6 19, 580

44

18

10,890

29,580

c TVaOP

64,400

Nov. 4

a Calculated. b Na, 18,600; K, 980 parts per million. «Not more than 25 parts per million.

1. Rattlesnake Spring, on Harrison ranch, half a mile above Washington ranch, 1 mile north of Black 

River, and 12 miles above Blue Springs. Flows through Rattlesnake Creek and empties into Black River 

about 1 mile below source.

2. Main spring of Blue Springs, sec. 28, T. 24 S., R. 26 E.

3. Black River Springs, at diversion dam on upper Washington ranch, about 12 miles above Blue Springs 

and 1 mile south of Rattlesnake Spring.

4. Clark well, near saltlake in Alkali Plat, sec. 24, T. 22 S., R. 29 E.

5. West end of salt lake in sec. 17 (?), T. 23 S., R. 29 E., on east side of Pecos River east of Loving.

The water from Eattlesnake Spring is a normal limestone 

water, which may come wholly from a limestone cavern without 

contamination from neighboring beds of rock salt and gypsum. As 

this spring is only a little way from Carlsbad Cavern, it may be 

the outlet of the water from that cavern. The water of Blue Springs 

is a limestone water to which'has been added much calcium sulphate. Apparently the underground drainage from some bed of 

gypsum, joins the stream from one of the limestone caverns. Black 

River Springs are only a mile from Eattlesnake Spring, yet the 

waters are very different. That from Eattlesnake Spring is a 

limestone water, whereas that from Black Eiver Springs is a strong 

gypsum water. The differences shown by these three analyses provoke speculation as to the cause. As thick beds both of limestone 

and O'f gypsum occur near by, it seems clear that the Eattlesnake 

Spring derives its supply chiefly from limestone, the Black Eiver 

Springs chiefly from gypsum, arid the Blue Springs from both.

The water of the Clark well contains much salt and gypsum, 

as is to be expected from the location of the well, in red shale that 

contains much rock salt and anhydrite. There is little limestone 

near this well.

The lake water is derived from drainage of the rocks from which 

the well water comes. Springs of salty water from these rocks discharge into the lake. Eeports as to this lake are conflicting. It is said 

that salt crystals are forming on the bottom, yet this analysis shows
EROSION BY SOLUTION AND FILL-. 121

that the water ig far from being saturated. The. country about 

Alkali Flat drains into this lake, and some of the springs are locally believed to be poisonous, but the analysis shows no poisonous 

properties.

SUMMARY.

Pecos Valley, in southeastern New Mexico, is a succession ol 

broad, shallow depressions which can be attributed only in part to 

surface erosion. The chief cause of these basins is believed to be 

local subsidence due to the removal by solution of soluble rock near 

the surface.

Through sink holes the surface debris which in most other regions 

is removed by run-off is here carried into subterranean caverns. 

The water that washes the debris into the caverns dissolves the 

soluble rocks and forms other caverns, which are similarly filled 

later. The transfer of soluble material from below ground to the 

surface at some lower altitude and of surface waste to underground 

caverns is not unknown but has not been sufficiently emphasized 

to make it a familiar process of erosion. In Pecos Valley it is 

a dominant process.

PEDESTAL ROCKS IN STREAM CHANNELS.

By KIRK BRYAN.

INTRODUCTION.

Isolated masses of rock, especially those of unusual shapes, excite 

much interest and are commonly regarded with some little awe a 

relic, perhaps, of those feelings and impulses which caused the erection of the great stones of the Druid monuments. The fanciful or 

mythical names that are almost spontaneously applied to such rocks 

testify to this popular interest, but the origin of these masses has 

received only scant notice by scientific men. This attitude is no 

doubt justifiable on the ground that there are more important matters for study. However, the type of isolated rock consisting of a 

larger mass above supported on a more slender pedestal has been 

used as a criterion in the study of larger problems. Such pedestal 

rocks have been cited as a measure of weathering since glaciation 1 

and also as proof that an area was not covered by continental ioe. 2 

That pedestal rocks may be formed by the sand-blast action of winds 

seems probable, but that such rocks in arid regions are necessarily 

proof of wind scour has been denied in a previous publication,3 in 

which a fairly complete list of papers on the affirmative of this 

question may be found.

The object of this paper is to call attention to some examples of 

pedestal rocks of well-developed form that stand in stream channels 

and are produced by a process which bears no causal relation to wind 

erosion, yet that, if found in some other environment, might easily be 

confused with pedestal rocks resulting from wind scour.

Two of the examples cited have not been seen by me. One is described from a photograph and notes by Willard D. Johnson, whose 

untimely death cut short the career of a keen observer much interested in the minutiae of erosive processes. The other was called to 

my attention by my friend and colleague, H. T. Stearns, who has allowed me to use his photograph and notes. William Donahue, of 

Spokane, furnished the photograph of the Devils Top.

1 Hughes, T. M., On some perched blocks and associated phenomena: Geol. Soc. London 

Quart. Jour., vol. 43, pp. 522-539, 1886.

3 AJden, W. C., The: Quaternary geology of southeastern Wisconsin : U. S. Geol. Survey 

Prof. Paper 106, p. 41, pi. 16, A, 1918.

3 Bryan, Kirk, Pedestal rocks in the arid Southwest: U. S. Geol. Survey Bull. 760, pp. 

1-11, 1923 (Bull. 760-A).

123
124 CONTRIBUTIONS TO GEOGRAPHY OF UNITED- STATES, 1923-1924.

DEVILS TOP AND SIMILAR BOCKS NEAR SPOKANE,

WASH.

Spokane, Wash., lies at the eastern margin of the Columbia 

Plateau, which terminates here in black cliffs and crags of basalt that 

front on the broad valleys of Spokane and Little Spokane rivers. 

In these valleys stand outlying portions of the plateau bounded by 

similar cliffs. Spokane Elver within the city plunges over ledges 

of basalt in Spokane Falls and about 7 miles below the city enters 

the long canyon that forms the northeastern boundary of the Columbia Plateau. The basalt flows that form the top of the plateau, 

known as the " rim rock " flows, have an altitude of about 2,400 feet. 

The flows that crop out in the bed of Spokane River and in the immediately adjacent cliffs are a younger series that attain an altitude 

only slightly above 2,100 feet. They lie within ancient valleys 

eroded in the plateau. These valley flows, though younger than 

the flows of the plateau, are thought to belong to the same general 

period of volcanism, in Tertiary time.4 The lavas of this series, at 

least in the immediate vicinity of Spokane, do not have the columnar 

jointing normal to basalts but are divided into great blocks by widely 

spaced joints. In consequence they yield on erosion large masses, 

many of which have peculiarly striking forms. Some of the most 

interesting of these masses are to be found in the canyon traversed 

by the lower course of Deep Creek, a stream that rises on the plateau 

and flows northeastward about 15 miles to Spokane River, which it 

enters 8 miles below Spokane. The stream plunges over the "rim 

rock" basalt and has cut a deep and narrow gorge in the younger 

basalt flows, which form a shelf along Spokane River. The lower 

part of the canyon is at one place only about 50 feet wide, and here 

is the Devils Top, one of a number of blocks that have fallen from 

the cliffs above. As shown in Plate XXXI, A, this block tapers 

from a rounded top to a narrow base. The rock would fall but for 

the fact that it rests against the side wall. It is nearly circular in 

plan and about 30 feet in greatest diameter. It is about 28 feet high 

and the tapering base is about 3 feet in diameter where it rests on the 

bedrock of the stream channel.

The rounded form of the upper part of the Devils Top is a characteristic weathering form of the basalt of this locality, and similar 

rounded domes cap the cliffs from which this block has undoubtedly 

fallen. The minutely and irregularly fractured surface is also 

characteristic and may be ascribed with some assurance to frost 

action. Only in shape does the rock differ from adjacent blocks.

* Pardee, J. T., and Bryan, Kirk, Geology of the Latah formation in relation to the 

lavas of the Columbia Plateau near Spokane, Wash.: U. S. Geol. Survey Prof. Paper 

140-A (in press).
PEDESTAL BOCKS IN STREAM CHANNELS. 125

The undercut sides seem, however, to be due to the erosive work of 

the stream. Deep Creek has strong freshets each spring, and during 

these freshets the velocity of the water around the rock must be high, 

because of the reduction in the width of the channel. The driftwood 

on the top of the rock, plainly visible in Plate XXXI, J., shows that 

the rock is at times overtopped by the stream, but the action of the 

stream is more prolonged and effective on the lower part of the 

rock. Here the force of the moving water, with its contained debris, 

removes the small blocks already loosened by frost, and perhaps 

the freezing of the water in winter facilitates such loosening. That 

direct scour does not seem to take much of a part in this process is 

shown by the lack of polished surfaces.

Undercutting by streams is hardly a common phenomenon in 

this region, and there are cliffs and individual rocks along Spokane 

Kiver and elsewhere in the region that are not notched. On the left 

bank of Columbia River below China Bar, however, there are a group 

of rocks of which some are loose blocks and others are portions of 

a lava flow isolated by weathering along widely spaced joints. The 

lava is part of the great series underlying the Columbia Plateau 

but resembles in its lack of columnar joints and method of weathering the flows on Deep Creek, which are doubtless somewhat younger. 

Some of these blocks have vertical walls, and others are notched 

near low-water level. The rock shown in Plate XXXI, B, approaches the form of a pedestal rock. The minutely and irregularly 

fractured surfaces of the block indicates weathering by mechanical 

forces, but examination of the interior of these fractured pieces 

shows that there has also been some chemical action. Apparently the 

effect of the river water is to speed up mechanical erosion and remove partly weathered fragments. Doubtless the undercutting 

would be more marked if the river held a nearly constant level, so 

that its action affected only a small zone. But Columbia River is 

subject to a prolonged annual rise of 30 to 40 feet. The maximum 

estimated discharge of the river at Wenatchee and Vernita, the 

nearest stations downstream, was 710,000 second-feet, on June 7, 

1894, and the minimum discharge 23,900 second-feet, on January 31, 

1917.5 During such floods the water 'doubtless has the same effect on 

all parts of the rock. In the rise and fall also the surface of the 

water occupies every position on the rock. Not only do these conditions tend to diminish the relative intensity of the notching action, 

but it is obvious that on a river subject to such floods pedestal rocks 

with slender pedestals would be snapped off, and there is thus a 

limit to the development of such forms.

6 Parker, G. L., and Lee, Lasley, Summary of hydrometrlc data in Washington, 1878- 

1919: U. S. Geol. Survey Water-Supply Paper 492, p. 118, 1923.

92818" 25 9
126 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

ROCK IN OWENS RIVER, CALIF.

The photograph reproduced in Plate XXXII, J., was taken by 

Willard D. Johnson in the canyon of Owens Kiver, Inyo County, 

Calif. According to his notes the locality is "just above the junc- 

,tion of Burcham Canyon and 'The Bridge'"; the rock is rhyolite 

of the " exfoliating type " found thereabouts and contrasting with 

a neighboring type which yields to weathering largely by solution. 

Johnson records also that the boulder is said to have developed the 

neck or pedestal in the 20 years that it had been under, observation 

by ranchmen in the neighborhood.

At this point Owens Kiver runs in a deep canyon and, as indicated in Plate XXXII, A, is swift and turbulent. However, as 

shown by the records of the United States Geological Survey gaging 

station near Round Valley, just above the junction of Rock Creek, 

at the lower end of the canyon, the flow of the stream is relatively 

steady. The yearly mean discharge has ranged from 181 to 380 

second-feet. The maximum recorded discharge of 1,190 second-feet 

occurred in June, 1907, and the minimum of 100 second-feet in February, 1919. Evidently the ordinary flow, fluctuating over a narrow range, has eroded the neck of the rock, and the flood flows are 

not severe enough to break it off.

The region has an arid climate and might even be called a desert. 

The river in the canyon descends from an altitude of 6,700 feet to 

4,400 feet, and the climatic conditions are similar to those at the 

.nearest towns, Bishop and Laws, which have an altitude of about 

4,100 feet. The 16-year rainfall record at Bishop, as compiled by 

Lee,6 shows an annual mean of 5.61 inches, and the 14-year record 

at Laws, 4.40 inches. Even if allowance is made for an increased 

rainfall in the locality of the pedestal rock on account of its greater 

altitude, it may still be considered in an arid region.

Though the statement of the local ranchers recorded by Johnson 

that the shape of the rock was developed in 20 years can hardly be 

true, it is evident from the photograph that stream abrasion operating against the surface of a rock already divided into small flakes 

by exfoliation has produced the notch that forms the neck. The 

neck is excentric, and the greater overhang on the upstream side 

may be due to greater wear on that side. The rock appears also to 

have been slightly polished by the water and its contained suspended matter.

8 Lee, C. H., An intensive study of the water resources of a part of Owens Valley, 

Calif.: U. S. Geol. Survey Water-Supply Paper 294, p. 91, 1912.
U. S. OEOLOCICAL SURVEY fiULLETIN 7(10 PLATE XXXI

A. DEVILS TOP, DEEP CHEEK CANYON, 8 MILES NORTHWEST OF 

SI'OKANE, WASH.

B. INCIPIENT PEDESTAL ROCK, COLUMBIA RIVER BELOW CHINA BAR, 

9 MILES DOWNSTREAM FROM JUNCTION OF SPOKANE RIVER, WASH.
U. S. GEOLOGICAL SURVEY BULLETIN 760 PLATE XXXII

A. PEDESTAL EOCK IN OWENS UIVER, INYO COUNTY, CALIF.

B. PEDESTAL ROCK IN GIBBON RIVER AT CHOCOLATE CASCADE, YELLOWSTONE PARK, WYO.
PEDESTAL BOOKS IN STREAM CHANNELS. 127

ROCK IN YELLOWSTONE NATIONAL, PARK.

The pedestal rock illustrated in Plate XXXII, #, is one of the 

features of Chocolate Cascade, a small rapid in Gibbon River 3 

miles southwest of the well-known Norris Basin, in Yellowstone National Park. According to H. T. Stearns, who visited the locality 

in 1923, the rock is composed of rhyolite. As is evident from the 

photograph, it is a remnant of a ledge, and the notched rock, or 

incipient pedestal rock, on the right, once belonged to the same 

ledge. Doubtless at one time there was at this place a considerable 

fall. The stream has eroded the ledge in such a way as to leave 

remnants which, though obstructing the flow, were strong enough 

to resist being carried entirely away.

Gibbon Eiver at the United States Geological Survey gaging station 4 miles above its mouth has a drainage basin'of only 117 square 

miles and a minimum recorded discharge of 62 second-feet. No 

gagings have been made at high water, but the maximum discharge 

is probably not much over four times this amount. The incomplete 

record indicates that the stream has a relatively steady flow, such as 

might be expected of a stream rising in well-wooded mountains and 

having a number of meadows and swamps along its course.

On account of prevailing low temperatures the climate of the area 

is relatively humid, although the mean annual precipitation shown by 

a 32-year record at the Weather Bureau station at Yellowstone is 

only 18.70 inches. Much of this precipitation falls as snow, and 

the result is that the vegetation and most of the erosional features 

of the area are those of a humid country.

CONCLUSIONS.

The rocks described in the foregoing paragraphs are, so far as 

form alone is concerned, typical "mushroom" or pedestal rocks. 

They are composed of material of almost equal hardness from base 

to top and have attained their form as the result of differential 

scour rather than differential weathering. Thus they differ in composition and origin from the pedestal rocks described in a previous 

publication.7

Save for the fact that these rocks occur in stream beds, they might 

be mistaken for rocks formed by wind scour. It is also entirely 

possible that rocks in arid regions formed by stream scour may have 

been mistaken for rocks formed by wind scour. Such confusion is 

the more likely in that the areas in which the examples cited in this 

paper occur have no great similarity in climate. Eastern Washington, in which the Devils Top and the rock in Columbia River were 

formed, has a subhumid or semiarid climate, typified by that of

7 Bryan, Kirk, op. cit.
128 CONTRIBUTIONS TO GEOGRAPHY OF UNITED STATES, 1923-1924.

Spokane, which has a mean annual precipitation of 18.85 inches and 

a cold winter. The Owens Kiver canyon lies in a warm arid region 

with an annual rainfall of only a little more than 5 inches. Yellowstone Park, on the other hand, has a cold humid climate. The character of the stream flow and the original form, position, and physical 

characteristics of the rocks are probably more influential than

climate in producing these remarkable forms.

c 

___ >

NOTE. The rock in Gibbon River, Yellowstone Park, has also been described 

by E. A. Martel, who visited the locality with the International Congress of 

Geographers in 1912. His note, illustrated with three excellent photographs, 

was published in the Comptes Rendus des Stances de 1'Academie des Sciences * 

de Paris, vol. 159, pp. 87-89, 1914. Martel has also described a large number 

of pedestal rocks in other localities, which he attributes to the action of both 

surface and underground streams.
INDEX

Alden, William C., The physical features of

central Massachusetts.._ 13-105

Analyses of waters from Pecos Valley, N.

Mex............................. 120

Arizona, southern, pedestal rocks in____ 7-10

"Auburn River," Mass., course of, in Tertiary time--______.__ 22-23,27

B

Barre Falls, Mass., plate showing_____ 105 

Blackstone Valley, Mass., Tertiary streams

in............................... 22,27

Blocks with vertical bedding planes, erosion

of-............. .............. 5

Bottomset beds of sand plain near Qlinton,

Mass., plate showing-_____ 70 

Boulders, glacial, in central Massachusetts.. 58-59 

glacial, in central Massachusetts, plates

showing_____________ 58 

of erosion, plate showing________.. 4 

perched, plate showing.._ 58 

Brimfleld, Mass., glacial lake near_____ 77-78 

Brookfleld, Mass., glacial lake at_____. 78-79 

Bryan, Kirk, Pedestal rocks in stream channels........................... 123-128

Pedestal rocks in the arid Southwest.... 1-11

C 

Calhoun, F. H., cited........ .......- . 36-37

Carlsbad Cavern, N. Mex., characteristic

scene in, plate showing _____ 112 

description of................. ...... 109-113

entrance to, plate showing______ 112 

Hattin's Dome and the Temple of the

Sun in, plate showing. _____ 112 

partition of onyx in, plate showing___ 112 

pillars of onyx in, plate showing____. 112 

spring deposits in, plate showing____. 112 

stalactites in, plate showing...____.. 112 

stalagmites and column in, plate showing. 112 

Twin Domes in? plate showing___.. 112 

Yeitso's Pillar in, plate showing____ 112 

Cavernous condition in rocks, possible depth

of--.. ...... . . 113

Caverns in rocks, drainage through____ 116-117 

Clay, laminated and crumpled, plates showing...___....__............ 38,71

Clinton, Mass., glacial deposits near___. 65-72 

Columbia River, Wash., incipient pedestal

rock on, plate showing. ____ 126 

weathered rocks on_____ _____ 125 

Connecticut Valley, glacial lakes in, history

Of-- .... 89-92

glacial lobe in, history of________ 87-89 

Crosby, W. 0., cited____s_____ 24,66,

D

Dana diorite, plate showing...___ ... 17 

D<5bris, falling of, into caverns___ 117-119 

Devils Top, in Deep Creek, Wash., description of 124-125

plate showing. ___________.__ 126 

Drift, glacial, nature of...............___ 29-31

Drip furrow below pedestal rock, plate showing..__________ 4 

"Dm ml ins in central Massachusetts __ 40-43

plate showing...________ 38

E

Emerson, B. K., cited____ 27-28,29,89-90,91-92

Esker, plate showing... . 38

Eskers in central Massachusetts.__ . 50-54

origin of 64

Flood plain, plate showing_.___ .... 58

"Flowstone," definition of....________ 110 

Foreset beds of sand plain near Clinton,

Mass., plate showing______ 70

Q 

Qlaciation, effects of, on rock at Clinton,

Mass., plate showing.._____ 31 

effects of, on rock in Greenland, plate

showing...___________ 30

stages of- . . 32-33

Gregory, H. E., cited ________ ... 1

Gypsum, sink holes dissolved in____ 114-116

Ice, glacial, thickness of____ ______ 36-37

Kame terraces in central Massachusetts.. 49-50 

origin of __....__ ... . . 47-49

Kettleholes, origin of..____________ 68-69 

plate showing....____________ 70

Lacustrine clay, deposit of, in central Massachusetts._____________ 37-38 

Lake Assabet, glacial, Mass., history of__ 74-75 

Lake Nashua, glacial, Mass., Ayer stage of.. 72-73 

glacial, Mass., Boylston stage of____ 61-65 

Clinton stage of.___________ 65-72 

map illustrating relations of ice front

to............*.................... 70

Quinapoxet stage of._________ 60-61 

Lake Quaboag, glacial, Mass., history of__ 79-81 

Lakes, glacial, origin of ___________ 59-60 

Lancaster, Mass., glacial deposits near___ 73 

Lee, Willis T., Erosion by solution and fill. 107-121

129
130 INDEX

Page

Lees Ferry, Ariz., erosion of rock cliffs at__ 2-3

pedestal rocks at, erosion of the pedestal. 5-6

run-off and drip of rain water from.. 3-4

Limestone breccia, orgin and volume of _ 113-114

Livingston ranch, N. Mex., wells in soluble

rocks on _____. _______ 115 

Lower Blase Dale Glacier, Greenland, plate

showing end of__________ 30

M

Massachusetts, central, dissected plateau of;

plate showing______ ___ 16 

central, early Tertiary streams and

valleys in.._.....__.____ 18-23 

extent of the area__________ 13-14 

ground and terminal moraines in_ 39-47 

later Tertiary stream adjustments in 23-27 

pre-Wisconsin deposits in_____ 37-39 

recent epoch in.,.________ 104-105 

relations of the topography to the

rock formations in_______ 27-29 

summary of glacial history of ____ 92-104 

map of, showing distribution of drumlins 38 

Moenkopi formation, hillock of, covered with 

gravel from Shinarump conglomerate, plate showing..... _ 4 

Monadnocks, examples of __________ 15 

Monson, Mass., glacial lake at_______ 79-81 

Moraine, ground, in central Massachusetts.. 39-43 

Moraines, terminal, in central Massachusetts 43-47

N

Nashua Valley, Mass., adjustments of drainage in.........._............... 23-27

Tertiary streams in ___________ 19-21 

New Mexico, central, pedestal rocks in___ 10-11

0

Owens River, Calif., pedestal rock in_.... 126 

pedestal rock in, plate showing.____ 127

Palmer, Mass., glacial lake at_ ......... 79-81

Pecos Kiver at Red Bluff dam site, N. Mex.,

plate showing..________ 112 

Pecos Valley, N. Mex., analyses of waters

froin__.___..__._____ 120 

location of. ... . 107-108

rocks of__________________ 108 

soluble material in__________ 109 

Pedestal rock, incipient, showing exfoliation,

plate showing... _____._ 4 

Pedestal rocks, in arid regions, forms and

origin of 1-11 

in streams, descriptions of ..____ 123-128 

plates showing_____. __. _____ 4 

Pelham, Mass., glacial lake near...__.__ 84-85 

Peneplain, Cretaceous, of central Massachusetts, development and dissection 

of . . - 15-18

Playa, plate showing. ____________ 112

Page

Potholes in bed of Blackstone River, Mass.,

plate showing...________ 104

Prospect Hill, near North Charlton, Mass.,

plate showing________:.. 38

Quaternary deposits, three classes of____ p 29 

Quinsigamond quadrangle, Mass., diagram

showing retreat of glacier in. In pocket 

map showing Quaternary geology of- In pocket 

Quinsigamond Valley, Mass., Tertiary

streams in... _ ... _ 21,27

R

Reservoirs on soluble rocks, leaks in____ 118-119 

Russell, G. H., cited .. . 116-117

S

Salt, cavities dissolved in_________ 114-116 

Sand, cross-bedded, overlying laminated

clay, plate showing_______ 71 

Shinarump conglomerate, block of, with 

vertical bedding planes, plate 

showing-_____________ 4 

Sink holes, east of Carlsbad, N. Mex., plate

showing.__________-._ 112 

produced by solution of salt and gypsum. 114-116 

Southbridge, Mass., glacial lake near_..... 76 

Spokane, Wash., basalt flows near___..... 124 

Stains on under side of boulder, plate showing 4 

Stream channels, glacial, in central Massachusetts_____J_____.... 55-56 

Stream terraces, glacial, locations of__..... 56-57 

glacial, origin of.___-__ .... ... 57-58 

plate showing..... 58 

Striae, glacial, directions of . 34-36 

Swift River, Mass., glacial history of. 82-84

T

Till, glacial, plate showing hill of- ___..... 17 

Travertine, deposition of, in Pecos Valley 114 

in Last Chance Canyon, N. Mex., plate

showing-.._._....... ... 112

V

Vermilion Cliffs, Ariz., plate showing 4 

W

Wachusett Mountain, Mass., plate showing- 16 

Ware quadrangle, Mass., diagram showing retreat of glacier in... . In pocket 

glacial lakes and streams of_-..-..--... 75-92 

map showing Quaternary^ geology of

. _________'. ........ In pocket

Ware River, Mass., glacial history of 81-82 

Warren, Mass., glacial lake near ___. _ 78 

Water, kinds of, in the Pecos Valley, N.

Mex..... 119-121

Wind-blown sand, erosion by... . 6-7 

Woolen mill, Gilbertville, Mass., plate showing.. . .. 105

Y

Yellowstone National Park, pedestal rock

in.. 127

pedestal rock in, plate showing.... 127

o

o a 69

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