DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SUEVEY

GEORGE OTIS SMITH, DIRECTOR

WATER-SUPPLY PAPER 232

UNDERGROUND WATER RESOURCES 

OF CONNECTICUT

BY

HEEBERT E. GREGOEY

WITH

A STUDY OF THE OCCURRENCE OF WATER 

IN CRYSTALLINE ROCKS

BY

E. E. ELLIS

PROPERTY OF 

U.S. GEOLOGICAL SURVEY

WASHINGTON

GOVERNMENT PRINTING OFFICE

1909
CONTENTS.

INTRODUCTION. ............................................................ 9

CHAPTER I. GEOGRAPHY. ................................................. 11

Topography........................................................... 11

General relations................................................... 11

Physiographic features............................................. 12

The highlands................................................. 12

The western highland...................................... 12

The eastern highland....................................... 14

Valleys in the highlands.................................... 14

Central lowland................................................ 16

Extent and character...................................... 16

Lava ridges................................................ 16

Farmington and Connecticut valley lowlands................ 17

Coast line..................................................... 17

Drainage.............................................................. 17

Forests................................................................ 20

Climate.............................................................. 20

Meteorological data................................................. 20

Summary.......................................................... 26

Surface-water supply.................................................. 27

Source and character............................................... 27

Quantity available................................................. 28

Population and industries.............................................. 30

CHAPTER II. GEOLOGY. ................................................... 31

Outline of geologic history.............................................. 31

Descriptive geology.................................................... 34

Introduction...................................................... 34

Crystalline rocks................................................... 35

Distribution and character...................................... 35

Joints........................................................ 37

Faults........................................................ 38

Triassic sandstone and trap......................................... 38

Distribution.................................................. 38

Stratigraphy.................................................. 38

Joints........................................................ 40

Faults........................................................ 41

Pleistocene drift................................................... 42

Distribution and general relations.............................. 42

Character of material........................................... 42

3
4 CONTENTS.

Page.

CHAPTER III. OCCURRENCE AND RECOVERY OP GROUND WATER. .......... 44

Circulation of ground water............................................. 44

The water table.................................................... 44

Movement of ground water........................................ 45

Porosity........................................................... 45

Permeability..................................................... 46

Artesian conditions. .............................................. 48

Springs........................................................... 50

Amount of ground water................................................ 51

Temperature of ground water.......................................... 52

Contamination........................................................ 53

CHAPTER IV. GROUND WATER IN THE CRYSTALLINE ROCKS or CONNECTICUT,

by E. E. Ellis........................................................... 54

Introduction...............................^.......................... 54

Literature............................................................ 54

Distribution and character of crystalline rocks in Connecticut............ 56

Rock types........................................................ 56

Granite........................................................ 58

Gneiss......................................................... 58

Schist........................................................ 58

Quartzite schist............................................... 58

Pegmatite.................................................... 59

Trap rock..................................................... 59

Limestone.................................................... 59

Drilling products................................................... 59

Drift.............................................................. 60

Conditions affecting occurrence of water in crystalline rocks............. 60

Introduction...................................................... 60

Joints............................................................ 61

Vertical joints................................................ 61

Horizontal joints.............................................. 62

Relations of rock type to jointing.............................. 62

Joint direction................................................ 63

Structure planes............................................... 63

Variation in jointing........................................... 63

Faults............................................................ 65

Circulation and storage of water....................................... 65

Influence of joints and other openings. ............................ 65

Spacing of vertical joints...................................... 65

Spacing of horizontal joints.................................... 66

Continuity of horizontal joints................................. 66

Continuity of vertical joints................................... 67

Fissility and schistosity openings............................... 67

Intersection of fractures....................................... 67

Opening of joints............................................. 68

Number of contributory joints. ............................... 70

Water level. ..................................................... 70

Direction of circulation........................................... 72

Decomposition as a measure of circulation........................... 73

Storage of water................................................... 74
CONTENTS. 5

Page. 

CHAPTER IV. GROUND WATER IN THE CRYSTALLINE ROCKS OF CONNECTICUT,

by E. E. Ellis Continued.

Tabulated well records................................................. 77

Practical applications................................................. 91

Percentage of failure of wells....................................... 91

Variations in yield and depth...................................... 92

Limit of depth for wells in crystalline rocks......................... 93

Quality of water.................................................. 94

Temperature of water.............................................. 94

Location of wells................................................. 94

Constancy of yield................................................. 95

Flowing wells..................................................... 96

Wells in varying rock types........................................... 97

Wells in granite.................................................. 97

Wells in schist and gneiss......................................... 98

Wells in quartzite schist........................................... 99

Wells in phyllite................................................. 99

Wells in limestone................................................ 99

Wells in granodiorite.............................................. 100

Statistical tables...................................................... 101

CHAPTER V. GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS. ........... 104

Introduction.......... ................................................ 104

Water within the rocks................................................ 104

Conditions of occurrence........................................... 104

In sandstone...................................................... 104

In conglomerate................................................... 106

In shales.......................................................... 106

In trap..........................J................................ 107

Water in bedding planes............................................... 107

Conditions of occurrence........................................... 107

Black shale....................... .............................. 109

Water in joints........................................................ 109

Vertical and horizontal joints....................................... 109

Direction and continuity of jointing............................... 112

Spacing of joints.................................................. 112

Opening of joints................................................. 113

Joints in trap..................................................... 113

Water along fault lines................................................. 114

Records of wells in Triassic sandstones, conglomerates, and shales......... 115

Wells in trap.......................................................... 128

Practical applications................................................. 130

Yield of wells.........................................:........... 130

Depth of wells................................................... 131

Quality of water.................................................. 132

Temperature..................................................... 132

Height of water in wells........................................... 133

Flowing wells..................................................... 133

Location of wells................................................. 135

Statistical tables...................................................... 136

CHAPTER VI. WATER IN THE GLACIAL DRIFT ................................ 138

Introduction.......................................................... 138
6 CONTENTS.

CHAPTER VI. WATER IN THE GLACIAL DRIFT Continued. Page.

Character and water capacity of drift................................... 138

Till. ............................".__.............................. 138

Stratified drift..:................................................. 139

Clay........................................:......... v ......... 140

The drift as a water reservoir.......................................... 140

Water bed at contact of rock and drift.................................. 142

Wells in till and stratified drift......................................... 142

Water horizon..................................................... 143

Depth and yield.................................................. 144

Quality of water.................................................. 145

Water level...................................................... 146

Cost of wells. ........................................................ 147

Records of wells in till................................................. 147

Records of wells in stratified drift....................................... 151

CHAPTER VII. WATER SUPPLY OF TYPICAL AREAS. ............................ 157

Supply of a highland town Warren.................................... 157

Supply of a lowland town North Haven................................ 160

Supply of a coast region Branford Point................................ 162

CHAPTER VIII. CHARACTER OF GROUND WATER OF CONNECTICUT. ............. 165

Introduction.......................................................... 165

Composition.......................................................... 166

Determining character. ........................................... 166

Hard and soft water.............................................. 166

Material taken into solution........................................ 167

Normal distribution of chlorine......................................... 168

Uses of water.......................................................... 169

Water for domestic purposes......................................... 169

Water for boilers.................................................. 169

Contamination.......................................................... 170

Introduction...................................................... 170

Contamination by sewage........................................... 171

Location of wells............................................... 171

Depth and construction of wells................................. 172

Contamination in different rock types............................ 172

Contamination by sea water......................................... 174

Relative value of water supply..................................... 175

Analyses............................................................... 175

CHAPTER IX. WELL CONSTRUCTION IN CONNECTICUT......................... 180

Dug wells.............................................................. 180

Drilled wells........................................................... 181

Driven wells.......................................................... 182

CHAPTER X. SPRINGS. .................................................... 185

Introduction.......................................................... 185

Types of springs....................................................... 185

Seepage springs.................................................... 185

Stratum springs................................................... 186

Fault and joint springs............................................. 187

Temperature of spring waters............................................ 187

Intermittent springs................................................... 188

Mineral springs......................................................... 189

Volume of springs..................................................... 189

Use and production of spring waters..................................... 189

Records of springs..................................................... 189

BIBLIOGRAPHY ............................................................. 196

INDEX ................................................................... 197
ILLUSTRATIONS.

Page. 

PLATE I. A, Vertical joints in granite; B, Horizontal joints in granite......... 60

II. A, Joints in schist and metamorphosed diabase; B, Jointed and fissile

schist.......................................................... 62

III. A, Flowing well at Noroton Heights; B, Weathering due to ground

water in granite quarry......................................... 96

IV. A, Vertical and horizontal joints in sandstone; B, Vertical and horizontal joints in trap............................................ 106

V. Map of Connecticut, showing distribution of chlorine ................ 168

FIGURE 1. Map of Connecticut, showing physiographic provinces .............. 13

2. Diagram showing precipitation at Storrs........................... 21

3. Diagram showing precipitation at New Haven.................... 22

4. Diagram showing precipitation at Cream Hill..................... 23

5. Diagrammatic section illustrating seepage and growth of streams... 45

6. Diagram illustrating artesian conditions where water does not rise to

the surface.................................................... 48

7. Diagram showing formation of a stratum spring at an outcrop of an

inclined impervious stratum................................... 50

8. Diagram illustrating the manner in which a spring may form at the 

contact of soil covering and the impervious rock below, when the 

soil is removed by erosion...................................... 50

9. Diagram illustrating the manner of'formation of a spring at the contact of a pervious formation and an impervious formation, when 

dissected..................................................... 50

10. Diagram illustrating effects of tides on water table.................. 51

11. Areas of limestone, sandstone, and crystalline rock water supplies of

Connecticut.................................................. 57

12. Diagram illustrating the manner in which a well obtains water by

cutting joints................................................. 61

13. Sketch showing relation of water level to topography.............. 71

14. Logs of wells in crystalline rocks.................................. 77

15. Diagram illustrating depression of water surface at point of leakage

in sandstone................................................... 105

16. Well logs showing influence of the Triassic black shale in determining

water horizons................................................ 110

17. Well logs showing influence of the Triassic black shale in determining

water horizons................................................ 112

18. Fault zones in sandstone........................................ 114

19. Section of the Connecticut Triassic as a synclinal basin conditions

favorable for artesian wells..................................... 134

20. Section of the Connecticut Triassic as a simple faulted monocline 

conditions favorable for several small artesian basins............. 134

21. Actual condition of Connecticut Triassic faulting and jointing 

developed to such an extent as to preclude the possibility of large 

artesian basins................................................. 135

22. Spring deriving its supply from joints and upward-sloping bedding

planes........................................................ 136

7
« ILLUSTRATIONS.

Page.

FI»WRE 23. Section of hilltop showing suitable catchment and reservoir conditions for a water supply to the rock fractures................... 141

24. Section showing common relation of rock surface to overlying drift. 142

25. Generalized section showing relation of rock to glacial drift....... 142

26. Diagram of well at South Wellington, showing water horizon at contact of till and stratified drift.................................. 143

27. Map of Warren, showing location of wells........................ 158

28. Map of North Haven, showing location of wells.................... 161

29. Map of vicinity of Branford Point, showing location of wells...... 163

30. Diagram illustrating the manner in which a well near the sea may

be contaminated by salt water during the dry season............ 174

31. Diagram illustrating conditions for intermittent spring............ 188
INTRODUCTION.

The study of the ground water of Connecticut, the results of which 

are presented in the following pages, was begun in 1903 with the collection and examination of well and spring records and was continued 

at intervals during 1904 and 1905. During the autumn of 1905 

E. E. Ellis cooperated with the author in general investigations, and 

also made a study of the water in the crystalline rocks. In addition 

to the report on the special work assigned to him, Mr. Ellis has prepared parts of the chapters on occurrence and recovery of ground 

water, on character of water, and on well construction and has assisted 

in compiling data and in preparing illustrations.

For information regarding chemical analyses thanks are due to 

Prof. Herbert E. Smith, of New Haven, and Mr. George H. Seyms, 

of Hartford.

The writer wishes to express his great indebtedness to the well 

drillers of the State, who have freely given much valuable information regarding the occurrence and recovery of ground water. An 

unusual amount of carefully collected data has been furnished by 

Messrs. C. L. Grant, of Hartford; F. A. Champlin, of East Longmeadow, Mass.; C. L. Wright, of New Haven; R. L. Waterbury, of 

Glenbrook; H. B. King, of Hartford; and S. B. Hamilton, of Melrose, 

Mass.
UNDERGROUND WATER RESOURCES OF CONNECTICUT.

By HERBERT E. GREGORY.

CHAPTER I. 

GEOGRAPHY.

TOPOGRAPHY.

GENERAL RELATIONS.

In its physiographic relations Connecticut is part of the New 

England plateau, which is characterized by complex groupings of 

hills composed of igneous and metamorphic rocks; by a few broad 

valleys cut in softer and less resistant rock material; and by many 

narrow valleys intrenched in the plateau, and in the main occupied 

by important watercourses. Other topographic features date from 

the advent of the great ice sheet of Pleistocene or "Glacial" time, 

which completely remodeled the New England landscape, accentuating or subduing the previous topography and originating new land 

forms. The plateau is, however, so dissected as to present the appearance of a region of hills, valleys, and narrow plains, differing in extent 

and outline.

Viewed as a whole, the surface of Connecticut is a plateau sloping 

gradually from Cornwall and Goshen southeastward to the Sound. 

There are no high precipitous mountains or sharply cut canyons, but 

nevertheless the topography is rugged beyond the average of regions 

of slight elevation and great physiographic age. High cliffs and rock 

walls are exhibited in \he trap of the central lowland and along certain streams in the highlands, but the hilltops are on the whole 

rounded and the ridges show a tendency to a north-south alignment. 

The character of the relief and the prevalence of a north-south 

arrangement of the hills are well shown by the railroad map of the 

State, some of the lines occupying north-south valleys, and others 

crossing the ridges. The Highland division of the New York, New 

Haven and Hartford Railroad goes through the narrow defile at 

Bolton Notch, over the pass at Terryville, through the tunnel at 

Newtown, traversing 119 miles from Putnam to Danbury, though

11
12 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

th« direct distance between these points is but 89 miles. Likewise 

the Central New England Railway, running westward from Hartford, 

requires 67 miles of track to reach the New York state line, a distance 

of 44 miles, and crosses the Highlands at Norfolk Summit, an elevation of 1,298.58 feet. Norfolk, 2 miles farther west, with an elevation 

of 1,210.7 feet, is the highest railroad station in the State. The " Air 

Line" of the New York, New Haven and Hartford Railroad from 

Willimantic to Middletown is a short and direct east-west route, but 

its construction required expensive cuts and fills and bridges, and 

the grades are unsuitable for heavy traffic. On the other hand, the 

Northampton division of the same railroad, extending northward from 

New Haven to the Massachusetts line, is but 1 mile longer than the 

distance as measured on a map; and the Hartford division, which 

traverses the lowland from New Haven to Thompsonville, exceeds a 

direct line by only 2 miles. Even in the heart of the.highland areas, 

the Central Vermont Railway crosses the State in a north-south 

direction along the winding courses of Shetucket and Willimantic 

rivers with but 8 miles of track more than the direct distance. In 

fact, if a railroad were to be constructed from Putnam in a straight 

line westward across the State the difficulties of operation would be 

scarcely less than those encountered in truly mountainous districts.

PHYSIOGRAPHIC FEATURES.

Physiographically, Connecticut may be divided into the western 

highland, occupying that portion of the State west of a line running 

from New Haven to North Granby; the eastern highland, between 

Rhode Island and a line through Somers, Rockville, Glastonbury, 

Middletown, and Branford; and the central lowland, occupying the 

remainder of the area. (See fig. 1.) These three provinces have 

characteristic groupings of topographic features which have a direct 

bearing on the water resources of the State and which have been the 

controlling factors in its settlement and industrial history.

THE HIGHLANDS.

Western highland. The western highland increases in elevation 

from the Sound northward and contains areas of considerable size 

over 1,000 feet in height. In Barkhamsted the plateau reaches an 

elevation of 1,400 feet, in Colebrook of 1,500 feet, in Goshen and 

Cornwall of 1,600 feet, and in Norfolk of 1,700 feet, and it culminates 

in Bear Mountain, Salisbury, at 2,355 feet. The plateau terminates 

abruptly on the east and at certain points, as Compounce Pond, the 

rise from the lowland is precipitous. Differences in elevation and in 

character and prominence of rock outcrops and the presence of 

numerous valleys of widely varying depth, width, and extent, give 

the highlands an appearance of great complexity. They are not,
GEOGRAPHY. 13

however, a "region of disorderly hills/' but have been controlled in 

topographic development by geologic forces whose influence was felt 

throughout southern New England. It was noticed by Percival ° 

that the highlands "may both be regarded as extensive plateaus/'

which "present, when viewed from an elevated point on their surface, 

the appearance of a general level, with a rolling or undulating outline, over which the view often extends to a very great distance, 

interrupted only by isolated summits or ridges, usually of small exo Percival, J. G., Report on the geology of Connecticut, 1842, p. 477.
14 UNDERGROUND WATEK EESOUECES OP CONNECTICUT.

tent." A good view from any exposed point in the highlands confirms this impression of a plateau surface rather than a confused 

mingling of hills. As concisely stated by Professor Rice: a "If we 

should imagine a sheet of pasteboard resting upon the summits of 

the highest elevations of Litchfield County and sloping southeastward 

in an inclined plane, that imaginary sheet of pasteboard would rest 

on nearly all the summits of both the eastern and the western highlands.'' Certain mountains project above the general level of the 

plateau and many valleys are cut below it. Owing to the resistant 

character of the rocks composing them, Great Hill, Cobalt, 700 feet; 

Lantern Hill, Mystic, 520 feet; Mount Horr, Canton, 880 feet; Mount 

Prospect, Litchfield, 1,365 feet; Mount Haystack, Norfolk, 1,680 feet; 

and other points stand out as prominent landmarks above the general 

surface at their base.

The origin of the highland plateau is revealed by an examination 

of the composition and structure of its basement rock, which clearly 

shows that the surface as it now exists is not the result of accumulation of sediments of great thickness. The bed rock of the highlands is not sedimentary nor horizontal, but is metamorphic and 

igneous rock which has been folded and twisted and injected, and 

which could have been formed only at a great depth below the earth's 

surface. Mountains have been removed from western and eastern 

Connecticut, and the remaining rocks, with their bewildering complexity of structure, are but the stumps of old land masses which 

have been sawed horizontally across by the agents of erosion. If the 

present valleys were filled and a few projecting hills cut down the 

conditions of Cretaceous time would be restored and the highlands 

would appear as a plain the result of long-continued, ceaseless 

activity on the part of rain, frost, and streams.

Eastern highland. The counterpart of the western highland is 

found in the eastern part of the State, but the eastern highland represents much less contrast in relief and does not attain such altitudes. 

Practically all the prominent hills and ridges in this province, are 

under 700 feet in height, and only in the towns along the Massachusetts line is an elevation of 1,000 feet attained, the culminating points 

being Rattlesnake Hill, Somers, 1,080 feet; Bald Mountain, Somers, 

1,120 feet; Soapstone Mountain, Somers, 1,061 feet; Hedgehog Hill, 

Stafford, 1,180 feet; Bald Hill, Union, 1,286 feet; Stickney Hill, 

Union, 1,220 feet; Lead Mine Hill, Union, 1,140 feet; Snow Hill, 

Ashford, 1,213 feet; and Hatchet Hill, Woodstock, 1,040 feet.

Valleys in the highlands. The valleys in the highlands aire those 

which have been cut since the formation of the peneplain (see p. 33), 

and their character is determined by the rocks which they traverse 

and by the age and size of the streams which have occupied them.

a Rice, W. N., and Gregory, H. E., Manual of Connecticut geology, 1906, p. 20.
GEOGRAPHY. 15

The western highland is traversed by two well-marked valleys those 

of Housatonic-Norwalk and Naugatuck-Still rivers, which inclose a 

rectangle of the highest land within the State. These valleys are 

intrenched 400 to 600 feet in the plateau and, although not occupied 

by continuous streams, they constitute the only feasible lines of communication between the northern and southern parts of the western 

highland. The two valleys are connected by the gorgelike trough of 

the Housatonic, which cuts through the rock ridges with a fall of 10 

feet per mile. The Housatonic Valley at Danbury and at Canaan and 

the Naugatuck-Still Valley at Winsted widen into undulating plains. 

The Farmington Valley through the highlands is a gorge less than 

1,000 feet in width below Riverton, and still narrower at Hartland, 

where it is sunk 600 feet below the plateau, and at Satans Kingdom 

it is barely 200 feet wide. Nearly all the minor streams of the western 

highland are intrenched in fairly narrow valleys, except the Pomperaug, which meanders freely over a miniature lowland on Triassic 

sediments.

In the eastern highland the valleys entering the lowland are mostly 

short and narrow and of high gradient. One important valley gorge, 

now occupied by Connecticut River, leads from the central lowland 

southeastward to the Sound. The Thames Valley is a fiord to Norwich. Its eastern branch, the Quinnebaug, is a steep-walled valley 

to South Canterbury, above which it widens into a plain through 

Plainfield, Killingly, and Putnam. The Shetucket-Willimantic Valley is broad and open through most of its course, as are also its 

northern branches, which divide the highland into segments.

The floor of the highland valleys is bed rock, till, or stratified drift, 

no stream having entirely removed the cover of glacial drift along its 

path. Some streams, in fact, like the east branch of the Farmington, 

flow through almost their entire courses without reaching bed rock.

A glance at the topographic map shows that the chief valleys trend 

either north and south or northwest and southeast. For example, 

the Housatonic from Gay lords ville to Derby, the Connecticut from 

Middletown to Lyme, the Farmington from Colebrook to Farmington, and the Shetucket and many valleys of lesser size are alike in 

their north-south alignment. The Upper Connecticut, the Willimantic, the Mount Hope, Little River (Windham County), and several minor streams trend in a common direction. There is nothing 

in the nature of the rock which accounts for the common alignment 

of these two groups of valleys and, if only present geologic conditions 

are taken into account, the southeasterly courses of the Housatonic 

below New Milford and of the Connecticut below Middletown are 

anomalous, for these rivers leave well-developed valleys of limestone 

and sandstone and cut their way through the most resistant gneisses 

and schists. There seems no escape from the conclusion that they
16 UNDEEGEOUND WATEE EESOUECES OF CONNECTICUT.

established their courses on an ancient coastal plain which sloped to 

the southeast. As a result of the uplift and consequent erosion, the 

strata forming the plain have been removed, but the streams have 

maintained their original directions, cutting valleys deep into the 

rocks of the plateau. (See p. 19.)

It has been shown by Hobbs a that the main valley lines of the 

State coincide in direction with five prominent systems of joints and 

faults and there is doubtless some genetic relationship between the 

joints and the trend of trough lines.

CENTRAL LOWLAND.

Extent and character. The central lowland differs from the highlands in altitude, character of bed rock, drainage, and types of hills 

and valleys. In extent it is coincident with the larger of the two 

areas of Triassic sediments within the State. Except in the lava 

ridges, the altitude of the lowland averages about 100 feet and only 

in the region south of Middletown does it exceed 500 feet. As viewed 

from the highlands for instance, at Bald Mountain, Somers, or Box 

Mountain, Bolton, from Bristol, or from the ridges near Canton the 

lowland surface appears as a plain from which rise ridges of lava. 

The edges of the highland areas, as viewed from the lowland, present 

abrupt walls, as seen in Southington and Somers, or steeply rising 

slopes. In Glastonbury, Middletown, and Branford the lowland 

merges imperceptibly into the highland.

Lava ridges. The most marked topographic feature of the lowland 

and, in fact, of the entire State, is the series of basalt ridges which 

extend from North Granby to East Haven. As far south as Meriden 

the ridges form a continuous line of elevation broken only by gaps 

and passes. From the Hanging Hills this ridge line passes by a series 

of rough steps to Beseck Mountain and thence continues southward 

as Totoket and Saltonstall ridges.

The most prominent parts of this ridge system are Peak Mountain, 

665 feet; Talcott Range, the highest point of which is 960 feet; 

Rattlesnake Mountain, 750 feet; Ragged Mountain, 754 feet; Hanging Hills, 700 to 1,000 feet; Lamentation Mountains, 654 and 725 

feet; Higby Mountain, 920 feet; Beseck Mountain, 840 feet; Pistapaug Mountain, 640 feet; Totoket Mountain, 780 feet; Saltonstall 

Ridge, 240-245 feet. The culminating point is West Peak, Meriden, 

1,007 feet, which is fully up to the level of the highlands and furnishes 

a magnificent view of the Farmington-Quinnipiac Valley and the 

Wolcott Plateau beyond. The ridge of lava faces westward as a 

bold escarpment, but slopes gently to the east, where it merges into 

the lowland floor. Breaks through the ridge formed by streams or 

by faults furnish passes for railroads at Tariffville, New Britain, 

Meriden, and Baileyville.

a Hobbs, W. EL, River system of Connecticut: Jour. Geology, vol. 9, 1901, pp. 469-485.
GEOGRAPHY. 17

Farmington and Connecticut valley lowlands. The central ridge of 

lava forms a conspicuous and effective line of demarkation between 

the two parts of the central lowland the Connecticut Valley and 

the Farmington-Quinnipiac Valley.

The Connecticut Valley area from Thompsonville to Middletown 

is practically a plain of drift and till 5 to 10 miles in width and with 

differences in elevation of less than 200 feet. South and west of 

Middletown the valley area passes by gradual stages into the eastern 

highland and the central ridges. The elevations in the. Connecticut 

Valley lowland are drumlins and other glacial deposits and tillcovered sandstone knolls. The streams tributary to the Connecticut 

are ditches cut into glacial deposits. The Scantic, Podunk, Hockanum, and others seldom reveal rock floor; Stony-Brook (Suffield) 

is the type of a few streams which have cut through the drift to the 

sandstone below.

The Farmington-Quinnipiac Valley extends from New Haven 

northward across the State and is bounded on the west by the steep 

edge of the western highland and on the east by the broken wall of 

the central ridge. It is occupied by three rivers the Farmington, 

Quinnipiac, and Mill (New Haven) all of which, in common with 

their tributaries, flow almost entirely on glacial drift. From the 

floor of the Farmington-Quinnipiac Valley rise a number of trap 

hills which break the continuity of the plain. The most prominent 

of these are the Barndoor Hills, 600 to 700 feet; Mount Carmel, 737 

feet; West Rock, 405 feet; and East Rock, 359 feet. The level, 

drift-filled floor of this valley lowland, together with the slight 

difference in elevation between New Haven and the Congamuck 

ponds, made the valley an attractive route for a canal, which was 

built in 1829 and was later succeeded by the Northampton Railroad.

COAST LINE.

The coast line is much indented and presents a multitude of bays, 

headlands, points, inlets, and marshes. Rock islands occur in 

groups, as at Norwalk and off Branford, or are scattered irregularly 

along the shore. Westward-moving tides and currents have built 

innumerable beaches, bars, and spits along the coast, thus greatly 

modifying its original outline. The character of the coast is due to 

the fact that the land has been depressed, allowing the sea water 

to enter the old valley now constituting Long Island Sound and to 

drown the irregular southern edge of the denuded peneplain.

DRAINAGE.

Connecticut is drained largely by streams which rise within its 

borders. Only two streams of large size the Connecticut and the 

Housatonic carry water from lands beyond the State, and the 

463 IRE 232 09 2
18 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

Massachusetts section of the Housatonic serves but a small area. 

The three main river systems are the Housatonic, the Connecticut, 

and the Thames, which drain, respectively, 1,272, 1,443, and 1,164 

square miles, or altogether 78 per cent of the surface.

Of the streams which enter Long Island Sound independently 

the Byram, Mianus, Mill (Stamford), Norwalk, Saugatuck, Mill 

(Fair-field), Poquonock, Wopowaug, West, Mill (New Haven), Quinnjpiac, Hammonassett, Niantic, Mystic, Pawcatuck, and certain 

smaller ones the Quinnipiac, 35 miles long, is the only one over 20 

miles in length, and all have small drainage basins.

In a number of places the divides between adjoining drainage 

areas are ill defined and a few stream systems coalesce. Thus the 

limestone valley extending from New Preston to Bedford, N. Y., an 

area of slight relief, is drained by five streams that have independerit 

outlets to the sea the Mianus, Norwalk, Saugatuck, Housatonic, 

and the Croton (a tributary to the Hudson). Likewise the Quinebaug, Bigelow Brook, the Natchaug, and the Shetucket together 

form a closed ring of water surrounding ten towns in the northeastern part of the State.

The lower ends of the streams entering the Sound are drowned, 

and the tides, 4 to 7 feet in height, reach up these streams to a 

greater or less distance. For example, the Connecticut is tidal to 

Hartford, 44 miles; the Thames to Norwich, 15 miles; the Housatonic 

to Derby, 11 miles; the Quinnipiac to Quinnipiac, 10 miles. Accordingly the lower reaches of the streams along the coast line are of 

no value for water supplies.

The streams of the highlands have steep gradients and their flow 

is interrupted by numerous waterfalls and rapids. This is particularly true of the streams entering the central lowland and of small 

streams in general. Thus, the Farmington from Cold Spring, Mass., 

to New Hartford falls 29.76 feet to the mile; the Shepaug descends 

at the rate of 30.5 feet to the mile, making one drop, at Bantam, of 

108 feet in less than three-quarters of a mile; Moodus River falls 

350 feet in 2 miles. Even the Housatonic falls 3.5 feet to the mile 

from Stratford to Shepaug; 10.2 feet to the mile from Shepaug to a 

station 1.8 miles above Cornwall bridge; 19.4 feet to the mile from 

this last-named point to Falls Village; and 9.2 feet to the mile from 

Falls Village to Ashley Falls, one-half mile north of the Connecticut 

boundary line. The descent of the Housatonic is accomplished by 

stretches of gravelly rapids alternating with reaches of relatively 

quiet Water, but at New Milford, Bulls Bridge, and Falls Village 

there is an abrupt drop over rock ledges. At Falls Village the combined height of the falls is about 100 feet.tt

<* Porter, Dwight, Report on water power of the region tributary to Long Island Sound: Tenth 

Census, vol. 16,1885.
GEOGEAPHY. 19

The streams of the lowland area have slight fall and in some 

places are aggrading their valleys. The Scantic, Hockanum, Farmington, Pequabuck, Mill (New Haven), Farm, and others are sluggish 

streams which meander freely. The Quinnipiac, with a drainage 

basin of 156 square miles and a length of 35 miles, falls 5 feet to the 

mile from Plantsville to New Haven. The Connecticut has a fall of 

only 0.6 foot to the mile from Enfield Rapids to Hartford; and from 

Hartford to Saybrook no fall whatever. The entire fall of Connecticut 

River in crossing the State in the lowlands is about 30 feet, as compared with the fall of Housatonic and Willimantic-Shetucket-Thames 

rivers in the highlands 650 and 600 feet, respectively. There are, 

however, many waterfalls and rapids of considerable size and great 

picturesqueness along the streams of the central lowland.

Lakes, swamps, and salt marshes occupy 145 square miles of the 

State, the topographic map showing 1,026 lakes, the largest of which 

is Lake Bantam, with an area of 1.56 square miles, or 999 acres. 

Swamps are even more abundant than lakes, and if the smaller, 

partly drained ones are taken into account they number several 

thousand. The importance of these water bodies is evident. They 

furnish supplies for cities, add greatly to the beauty of the landscape, 

and are particularly effective in controlling the drainage, serving as 

reservoirs to retard the escape of rainfall and thus preventing destructive floods.

A glance at the map of Connecticut will show that the drainage is 

to the southeast and that the streams flow in accord with the general 

slope of the plateau, but even a superficial glance reveals the fact 

that not all the larger streams are in the prominent valleys and that 

many occupy positions where the bed rock is unfavorable for. valley 

development. The Connecticut, for instance, instead of following the 

sandstone to New Haven, leaves the lowland at Middletown and turns 

abruptly into the crystalline rocks of the highlands, through which 

it has cut a deep gorge. Likewise the Housatonic, which follows a 

limestone valley down to Still River, turns southeastward across 

rugged crystalline rocks instead of continuing in the valley indicated 

by rock structure. The same is true of a number of smaller streams. 

Anomalies of another class are illustrated in the arrangement of certain smaller streams whose direction and grade, as well as character 

of valley, are entirely out of accord with the present topography. 

For example, Still River at New Milford and a stream of the same 

name at Winsted flow in a direction contrary to the slope of their 

valleys and enter their master streams by dropping over falls. The 

Farmington follows the slope of the ancient peneplain from Colebrook 

River to Farmington, there turns northward, cuts through a trap 

ridge at Tarifrville, and finally reaches the Sound after flowing a dis-
20 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

tance of 103 miles instead of the necessary 64 miles to New Haven or 

74 miles by way of the Connecticut at Middletown.

Without going further into detail, it may be stated that the characteristic features of the present drainage are due to two main causes. 

First, the streams were established on a peneplain during Cretaceous 

time and followed the slope to the south and southeast regardless of 

the character of the underlying rocks. The Connecticut, Housatonic, 

and other streams have maintained this inherited position. Second, 

the entire drainage of the State has been modified by glaciation. The 

courses of some streams have been reversed, other streams have been 

cut in two, and still others have been entirely obliterated or are represented by lakes and swamps. In fact a widespread rearrangement 

of streams as to direction and grade has been brought about.

FORESTS.

The distribution of forests in the State follows closely the subdivisions into highland and lowland areas. The eastern and western highlands are largely forest covered, and in recent years the forest areas 

have been encroaching on the agricultural districts. In the central 

lowland the soil, transportation facilities, and nearness to market 

render agriculture more remunerative, and the forests are represented 

by small, scattered wood lots. Taken as a whole, Connecticut is a 

well-timbered country, 39 per cent of its area being covered with 

trees.

CLIMATE.

METEOROLOGICAL DATA, a

Sixteen climatological stations are maintained by the United States 

Weather Bureau in Connecticut at Bridgeport, Canton, Colchester, 

Cream Hill, Danielson, Hartford, Hawleyville, New Haven, New London, North Grosvenordale, Norwalk, Southington, Storrs, Torrington, 

Voluntown, and Waterbury. In Falls Village, Middletown, South 

Manchester, Wallingford, and West Simsbury record is kept of rainfall 

and temperature.

The following tables and figures 2, 3, and 4 present data collected 

at three selected stations; one in the eastern highland Storrs, at an 

elevation of 640 feet; one in the central lowland New Haven, elevation 25 feet; and the third in the western highland Cream Hill, 

elevation 1,300 feet. The tables for the New Haven station give 

records of rainfall, temperature, humidity, and wind velocity, which 

are controlling factors in ground-water supply.

a From United States Weather Bureau records.
GEOGRAPHY. 21

Precipitation (in inches) at Storrs, 1897-1906. 

[Elevation, 640 feet.]

Year.

1897...............

1898...............

1899...............

1900...............

L901. .............

1902...............

1903...............

1904........... .

L905. .............

1906..............

Mean. .......

Jan.

3.84 

4.70 

3.70 

3.42 

2.17 

2.53 

3.79 

4.55 

3.57 

3.16

3.54

Feb.

3.40 

4.03 

3.97 

7.31 

1.05 

5.11 

5.18 

2.80 

1.21 

2.68

3.67

Mar.

3.66 

3.00 

6.30 

6.73 

7.18 

6.35 

7.09 

3.31 

3.45 

5.46

5.25

Apr.

2.37 

4.44 

2.20 

2.67 

9.51 

3.88 

2.81 

6.40 

2.87 

4.40

4.16

May.

4.44 

3.81 

1.27 

4.91 

6.30 

1.59 

.50 

1.96 

.90 

5.87

3.15

June.

2.79 

2.48 

3.72 

4.32 

1.96 

3.24 

9.24 

2.53 

4.53 

2.18

3.70

July.

12.24 

6.24 

5.55 

2.76 

5.54 

7.48 

4.56 

1.85 

1.77 

5.03

5.30

Mean for season. .

Aug.

5.23 

5.87 

3.27 

2.03 

7.58 

2.17 

4.52 

6.00 

2.63 

2.16

4.15

Sept.

1.39

2.22 

3.31 

2.27 

4.33 

7.05 

1.81 

4.71 

5.79 

2.05

3.49

Winter.

11.31

Oct.

0.92 

6.18 

1.54 

3.00 

1.97 

5.68 

2.79 

2.19 

2.57 

4.85

3.17

Spring.

12.56

Nov.

7.14 

6.11 

2.10 

6.79 

3.04 

1.10 

1.95 

1.'47 

2.73 

2.39

3.48

Dec.

5.61 

1.96 

2.14 

2.22 

9.55 

5.86 

4.27 

2.42 

4.12 

2.80

4.10

Summer.

13.15

Annual.

53.03 

51.13 

39.13 

48.43 

60.18 

53.75 

48.51 

40.19 

36.14 

43.63

47.16

Fall.

10.14

10 20 30 40 50 60 70

1890 

1891 

1892 

1893 

1894 

1895 

1896 

1897

1898 

1899 

1900 

1901 

1902 

1903 

1904 

1905 

190G

Jan. 

Feb. 

Mar. 

Apr. 

May 

June 

July 

Aug. 

Sept 

Oct. 

Nov. 

Dec.

Winter 

Spring 

Bummer 

Fall

 

 

 i 

 i 

 

 

 i 

M 

 I 

 i 

 

 

 

 

 3.54 

 5.25 

 3.70 

 4.15 

 4.10 

I 11.31-

 12.56-

 -13.15-

 10.14-

Annual pr

Mean month

Mean annua

Mean seasoi

ecipitation, 1

ly precipitati

precipitatior

890 to 1906,

)n, 1897 to 1<

, 1897 to 190

al precipitation, 1897 to 1!

«H>

___

6

06

FIGUEE 2. Diagram showing precipitation, in inches, at Storrs.
22 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

Precipitation (in inches) at New Haven, 1897-1906. 

[Elevation, 25 feet.]

Year.

1897...............

1898...............

1899...............

1900...............

1901...............

1902...............

1903...............

1904...............

1905...............

1906...............

Jan.

3.85

4.90

4.33

3. CO

1.38

1.83

3.17

2.78

4.14

3.20

3.32

Feb.

2.00

3.39

6.39

.54

3.98

2.06

2.45

3.15

Mar.

3.66

4.21

5.09

2.96

5.67

Apr.

2.44

4.43

1 7O

9 03

3 40

2 fii

6 64

3 49

4.02

May.

K (1°.

8 no

K ro

3 on

1.61

01

2.94

1.18

3 91

June.

2 A.7

.21

2

KQ

1 79

4.35

7.41

2.46

5.87

5.14

S

OP:

July.

10.63

4.17

2.28

A An

3 26

2 17

2 08

2.86

4.25

Aug.

6.81

.65

Oft

2 14

6.96

6 97

7.20

i is

4 56

Sept.

o on

3 qq

2 in

5 7(1

5 84

2 20

4.96

5 H7

3.87

Oct.

1 9Pi

7 99

1 7fi

2 no

6.41

9 Q4.

2.21

2 91

7 44

3 64

Nov.

5.72

5

£Q

I

on

1.61

79 1 QP;

1.95

2.42

Dec.

9 11

1 56

2 14

7.65

6 49

2 53

3 64

4

QO

4.18

4.07

Annual.

r7 on

53.66

qe OQ

34.83

68.81

44.33

41.22

41.73

A0. °.°*

51.30

45.31

Mean for season............ ........

Winter.

10.54

Spring.

12.44

Summer.

12.06

Fall.

10.27

1ft 20 30 40 50 60 70

Mean annual precipitation, 1897 to 1906

Mean monthly precipitation, 1897 to 1906

Mean seasonal precipitation, 1897 to 1906

fig. 81

FIGUKE 3. Diagram showing precipitation, in inches, at New Haven.
GEOGRAPHY.

The average precipitation at New Haven for thirty 

December 31, 1903, was as follows:

Average precipitation at New Haven for thirty years ending Decem

Inche 

January. ................... ... 4. 0

February. ....................... 4. 0

]W"a T*r»T"i A K

April. ........................... 3. 4

May. ........................ .... 3. 7

June. ........................... 2. 9

July. ............................ 5. 0

August. . ......................... 4. 8

September 

October. . .

1890 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

1901

1902 

1903 

1904 

1905 

1906

Jan. 

Feb.

Mar. 

Apr. 

May 

June 

July 

Aug. 

Sept. 

Oct. 

Nov. 

Dec.

 Winter 

Spring 

Summer 

Fall

........................ 3.6

....................... 4.2

0 10 20 3

MM 

 

 

 

 

 I 

mmmm 

mmm 

mmm 

 

 

mmm 

 

 

 

 

 4.27 

 4.13 

 4.53 

 6.08 

 4.44 

 11.42 

 11.92 

 115.05 

 11.20

Annual pr

Mean montl:

Mean annus

Mean season

3.

3 Novei 

2 Decer 

1 

5

1 Mean

7 ^

\ 1 SSi

6 F

8

0 4

ecipitation, ]

y precipitati

precipitatio

al precipitati

Annual..... .....

for season:

pring....... ...'...

all

0 50

897 to 1906

on, 1897 to 1

u, 1897 to 19

:>n, 1897 - 19

»6

)6

6

) 7

Inches. 

3.73 

3.79

47.97

11.84 

11.67 

12.79 

11.67

0

FlQUSE 4. Diagram showing precipitation, in inches, at Cream H

23

rears ending

r 31, 1903.
24 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

Prtmpitati&n (in inehes) at Gream Sill, 1897-1906. 

[Elevation, 1,300 feet.]

Year.

1897...............

1898...............

1899...............

1900...............

1901...............

1902...............

1903.......---.....

1904...............

1905...............

1906...............

Jan.

3.52

3.47

2.82

1.52

3.93

4.69

6.91

2.41

3.61

Feb.

2.21

3.68

4.13

S Q7

.84

4 90

4.97

3.13

1.68

3.41

Mar.

2.09

5.84

3.84

7.33

4.68

4 94

4.46

3.12

4.06

4.27

Apr.

3 1 fi

i 31

1.47

1 95

6.83

4.76

3.20

3.12

2.74

3.67

3

KO

May.

6.70

1.75

S i ^

6 on

2 QQ

1 39

4.28

2.35

5.61

4.13

June.

2.87

3.39

4 49

1 69

S

AC

9.74

3.52

3.90

5.60

4 53

July.

Q 71

1.79

6.70

6.09

4.57

9 40

4.07

6.15

5.83

6.47

6.08

Aug.

5.28

6.77

1.11

6.97

4.70

5.65

3.89

4.71

3.14

4.44

Sept.

2.85

4.25

4.21

1 7S

4.52

7.83

2.85

7.90

6.83

3.58

4.66

Oct.

1.04

3.35

1.67

2.73

4.37

6.39

2.71

2.90

3.46

Nov.

5.54

6.46

1.59

5 29

Q 9fi

.75

3.10

1.24

2.19

1.36

3.08

Dec.

2.17

2.21

3.00

8.14

6.65

3.09

2.59

3.84

4.39

Annual.

49.32

48.24

37.54

61.43

56.85

48.20

45.75

46.31

49.58

Mean for season. ................ .... . . . . ...... ....

Winter.

11.41

Spring.

11.92

Summer.

15.05

Fall.

11.20

The average precipitation recorded at ten stations in Connecticut 

for the years 1893-1903 is as follows:

Average precipitation at ten stations in Connecticut, 1893-1903.

Inches. 

January..:......................... 4. 28

February.........'................ 3. 94

March............................. 4. 23

April............................. 3. 53

May..............:................ 4. 03

June............................. 2. 95

July.........................'..... 4. 42

August............................ 4. 30

September. ...................... 3. 34

October........................... 4. 04

Inches. 

November....................... 4. 48

December....................... 3. 44

Annual.................... 46. 98

Mean for season:

Winter...................... 11.66

Spring....................... 11.79

Summer...................... 11. 67

Fall.......................... 11.86

Monthly and annual temperature (°F.) at Storrs, 1893-1903. 

[Elevation, 640feet.]

Highest monthly

Lowest monthly

Jan.

24 

28 

17

Feb.

24 

28 

19

Mar.

36 

43 

29

Apr.

46 

48 

42

May.

56 

60 

54

June.

64 

68 

59

July.

69 

72 

65

Aug.

68 

70 

62

Sept.

61 

64 

56

Winter.

:e

Oct.

50 

54 

45

Spring.

46

Nov.

38 

44 

34

Dec.

30 

33 

23

Summer.

67

Annual.

47

Fall.

50
GEOGRAPHY. 25

Monthly and annual temperature (°F.) at New Haven, 1873-1903. 

[Elevation, 25 feet.]

Highest monthly

Lowest monthly

Jan.

28 

37 

20

Feb.

29 

36 

20

Mar.

35

45

27

Apr.

46 

52 

39

May.

58 

64 

51

June.

66 

71 

61

July.

72 

76 

68

Aug.

70 

73 

65

Sept.

64 

70 

59

Winter.

30

Oct.

53

58 

48

Spring.

46

Nov.

41 

47 

34

Dec.

32 

39 

26

Summer.

69

Annual.

50

Fall.

53

For thirty-one years the highest temperature at New Haven was 

100°, in September, 1881, and the lowest was 14° below zero, in January, 1873.

Monthly and annual temperature (°F.) at Cream Hill, 1897-1907. 

[Elevation, 1,300 feet.]

Highest monthly 

mean............ 

Lowest monthly

Jan.

23.1 

30.2 

17.3

Feb.

22.0 

26.6 

16.3

Mar.

32.9 

39.2 

26.0

Apr.

44.0 

45.4 

40.6

May.

56.0 

59.0 

53.8

June.

64.0 

66.0 

60.0

July.

69.4 

72.1 

66.1

Aug.

66.6 

70.6 

61.2

Sept.

61.4 

64.6 

58.6

Winter.

23.7

Oct.

51.0 

54.6 

47.6

Spring.

43.3

Nov.

36.7 

42.4 

32.2

Dec.

26.0 

29.7 

21.4

Summer.

66.7

Annual.

<:e

Fall.

49.7

Mean relative humidity (per cent} at New Haven, 1901-1906.

Year.

1901 ...............

1902...............

1903. ..............

1904. ..............

1905...............

1906...............

Jan.

72 

70 

71 

72 

68 

74

71

Feb.

62 

69 

73 

67 

63 

69

67

Mar.

74 

76 

78 

72 

71 

69

73

Apr.

77 

69 

65 

70 

66 

63

68

May.

79 

65 

65 

69 

71 

70

70

June.

70 

71 

82 

75 

74 

75

75

July.

80

77 

73 

75 

76 

82

77

Aug.

83

75 

79 

77 

81 

81

79

Sept.

80 

84 

79 

80 

80 

77

80

Oct.

76 

78 

79 

68 

71 

76

75

Winter. Spring.

70 70

Nov.

67 

79 

68 

72 

67 

67

70

Dec.

77 

72 

69 

70 

70 

72

71

Summer.

Annual.

75 

74 

73 

72 

72 

73

73

Fall.

75
26 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

Mean relative humidity (per cent) at Neiv Haven for fifteen years ending in 1903.

Time. Jan.

74

71

Feb.

73

72

Mar.

71

69

Apr.

74

74

May.

77

76

June.

78

78

July.

80

78

Aug.

80

80

Sept.

78

76

Oct.

76

74

Nov.

75

72

Dee.

76

72

Annual.

76

74

Average velocity (miles per hour) and direction of wind at New Haven, 1900-1905.

Year.

1900 Vel.....

Dir.....

1901 Vel.....

Dir.....

1902 Vel.....

Dir.....

1903 Vel.....

Dir.....

1904 Vel.....

Dir.....

1905 Vel.....

Dir.....

Mean Vel.

Dir.

Jan.

10.1

N.

9.9

N.

9.8

NW.

10.2

N.

10.3

N.

11.2

N.

10.3

N.

Feb.

11.3

W.

11.2

NW.

13.0

W.

10.0

W.

10.6

N.

10.7

W.

11.1

W.

Mar.

10.6

N.

11.0

NW.

11.4

N.

9.5

NE.

10.1

NW.

8.2

N.

10.1

N.

Apr. May.

9. 5 9. 1

N.

13.3

NE.

9.9

S.

11.7

N.

10.7

NW.

10.1

NW.

10.9

/ N. 

\NW.

SW.

9.8 s. 

9.2

SW.

8.0

S.

8.2

S.

9.0

S.

8.9

} S .

June.

8.8

SW.

7.8

S.

8.4

SW.

8.5

NE.

8.2

S.

7.8

S.

8.3

S.

July.

8.1

SW.

6.8

SW.

7.2

SW.

7.8

SW.

8.2

S.

7.8

S.

Aug.

7.1

SW.

6.9

S.

7.2

NW.

7.3

N.7.7'

S.

7.9

SW.

7. 7 " 7. 4

sw- {sw.

Sept.

8.

SW

1

7.1

SW

8. 4

N.

7. 9

SW.

8.

N.

8.

N.

8.

3

3

0

N. 

SW.

Winter.

Mean for season Vel. ....... ....... ............. 10. 5

Dir . N.

Oct.

9.0

N.

8.6

N.

8.2

.N

11.3

N.

9.5

N.

8.6

N.

9.2

}N.

Spring.

10.0

N.

Nov.

10.7

Dec.

8.9

N. SW.

10.2 1 10.4

NW. N.

9.4

N.

8.4

N.

9.0

NW.

9.8

NW.

9.6

. N. 

\NW.

10.8

N.

10.9

W.

10.7

N.

9.7

SW.

10.2

}N.

Annual.

9.3

S.W

9.4

N.

9.4

N.

9.3

N.

9.3

N.

9.1

N.

9.3

N.

Summer. Fall.

7.8 8.9

( S. \ M

\sw. / N -

Prevailing winds at Neu> Haven for thirty-one years.

January ...................... North.

February '. .................... North.

March.........................Northwest.

April....................... Northwest.

May......................... South.

June......................... South.

July........................ South.

August...................... South.

September................... Southwest.

October.....................North.

November....................North.

December....................North.

Annual.....................North.

SUMMARY.

The foregoing tables indicate that the climate of Connecticut 

possesses both continental and oceanic features directly related to 

the highlands and to Long Island Sound. The winters are long and 

severe; the summers are short, beginning abruptly in June arid passing gradually into winter through autumn. Areas of high and low 

barometer which affect the weather of the State pass to the north 

down the St. Lawrence Valley, along the coast or directly across the 

State. Precipitation is uniformly abundant, and excessively dry 

years are unknown. There has been little change in the annual 

amount of rain for one hundred years, and the variation in seasonal 

amount is slight. (See figs. 2 to 4.) In fact, Connecticut may well 

serve as a type of uniform, evenly distributed rainfall of ample amount, 

in contrast with regions of seasonal rains and great annual variation.
GEOGRAPHY. 27

The relation of temperature to ground-water problems is shown by 

the fact that percolation through sand is nearly twice as rapid at 

100° F. as at 50°, and, accordingly, the amount of rainfall absorbed 

by the ground is subject to large monthly and seasonal variation. 

The proportion of the total precipitation found in the ground at each 

month in the year is given in the following table: a

Humidity of the ground.

Month.

*

Per cent at 

1 foot.

89 

76 

66 

54 

44 

32

2 feet.

95 

82 

72 

57 

45 

30

3 feet.

P8 

88 

77 

65 

48 

30

Month.

July...............

Per cent at 

1 foot.

20 

32 

44 

57 

66 

82

2 feet.

15 

28 

40 

52 

64 

74

3 feet.

10

22 

34 

48 

67 

83

SURFACE WATER SUPPLY.

SOURCE AND CHARACTER.

* Of the water which falls as rain, a part is evaporated, another part 

enters the ground, and a third part goes directly into streams and is 

thus carried to the sea. The amount of water which is carried by streams 

has been approximately determined (see tables below), but there 

are no records of the amount evaporated, and accordingly the proportion of the rainfall absorbed by rocks and soils, and therefore 

available for springs and wells, is unknown. However, the amount 

evaporated is certainly small and, for rough calculations, the total 

rainfall may be divided into that which enters the ground (ground 

water) and that which is carried in streams (run-off).

The relation of rainfall to run-off can not be stated definitely, 

because several factors of unknown value are included. The rate of 

precipitation, the topography of the surface, the texture of the soil, 

and the structure of the rocks are all to be considered. The presence 

of lakes and swamps along the stream's course and on its catchment 

area modify the surface run-off, and a large but unknown amount of 

ground water enters streams and lakes without reaching the surface. 

For instance, Lake Saltonstall has a small drainage area 4 square 

miles and should receive 4,000,000 gallons of water a day. It 

actually receives, however, a much larger amount than can be 

accounted for by ordinary surface drainage and is presumably fed 

by subterranean springs and ground-water seepage.

 The presence of forests affects the relation of rainfall to run-off by 

increasing and regulating the flow of ground water. Deforestation

a Sherman, Connecticut Almanac, 1885, p. 39.
28 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

promotes evaporation, increases the run-off, and tends to produce 

seasons of flood.

The general run-off of streams in the eastern part of the United 

States is 0.05 to 0.5 cubic foot per square mile per second, and streams 

tributary to Long Island Sound carry 17J to 27 J inches of rainfall 

out of an annual total of 40 to 52 inches.a Variation in annual runoff is indicated by the record of Connecticut River, which shows the 

ratio of the run-off for a dry year to be 94 per cent of an average 

year's flow.

QUANTITY AVAILABLE.

The rivers whose discharge and run-off records are given below 

were chosen as typical Connecticut streams and fairly represent 

prevailing conditions. The Shetucket is a stream of the eastern 

highland, established on gneiss and schist. The Connecticut drains 

the sandstone lowland, and the Housatonic flows for a large part^pf 

its course above Gaylordsville in a limestone valley. The run-off 

record is compared with the rainfall record of the meteorological 

station nearest the point where the discharge is measured.

Discharge and run-off of Shetucket River at Willimantic April 4, 1904, to January 1, 1907'.,_

Date.

1904. 

April 4.........................

May......... ...................

July............................

December 1-17, 28-31 ............

1905.

Discharge (second-feet).

Maximum.

4,420 

2,350 

555 

345 

930 

2,930 

930 

990 

3,755

3,865 

4,195 

706 

1,560 

555 

2,930

Minimum.

758 

385 

84 

84 

126 

66 

207 

150 

126

275 

510 

275 

66 

207 

555

Mean.

1,784 

920 

326 

221 

373 

428 

396 

381 

831

1,937 

1,254 

455 

565 

364 

902

Run-off.

Per 

square 

mile 

(secondfeet).

4.50 

2.32 

.823 

.558 

.942 

1.08 

1.00 

.962 

2.10

4.89 

3.17 

1.15 

1.43 

.919 

2.28

Depth 

(inches).

4.51 

2.68 

.918 

.643 

1.09 

1.20 

1.15 

1.07 

1.64

5.64 

3.54 

1.33 

1.60 

1.03 

2.63

Relation 

to rainfall 

(per 

cent).

70.4 

136.7 

36.3 

34.8 

18.1 

25.5 

52.5 

72.8 

67.7

163.5 

124.0 

147.8 

35.3 

37.7 

63.8

Rainfall 

at Storrs 

(inches).

6.40 

1.96 

2.53 

1.85 

6.00 

4.71 

2.19 

1.47 

2.42

3.45

2.87 

.90 

4.53 

2.73 

4.12

<* Porter, Census for 1880, vol. 16, pt. 1.
GEOGEAPHY. 29

Discharge and run-off of Connecticut River at Hartford January 1, 1871, to January 1,

1886.

[Drainage area, 10,234 square miles.]

Date.

1871.......... .................

1872.......... .................

1873.......... .................

1874.......... .................

1875............................

1876............................

1877........:...................

1878............................

1879............................

1880............................

1881............................

1884...................... .....

1885.

May............................

July............................

Year.....................

Maximum.

87,460

98,100

109,800

134, 000

90,100

120,800

128,200

89, 350

116,400

65,550

74,000

74, 700

134,000

23,200

16,400

88,600

63, 700

27, 900

10,500

18,000

13,100

21,350

78,200

35,400

88,600

Discharge.

Minimum.

5,520

6,250

5,390

5,210

5,700

5,360

5,700

5,350

5,550

5,200

5,250

5,150

17 000

10, 500

7,600

13, 100

10,250

5,800

6,000

5,300

6,000

6,750

12,400

5,300

Mean.

17,433

19,335

23, 061

23, 340

18, 114

22, 080

16,683

20,766

18,852

13, 720

18,026

19,861

19, 157

34, 661

14,711

11,706

26, 250

25, 869

10,785

7,909

9,148

8,105

10, 084

33, 067

21, 005

17, 775

Per 

square 

mile 

(secondfeet).

1.70

1.89

2.25

2.28

1.77

2.15

1.63

2.02

1.84

1.34

1.76

1.94

1.87

3.38

1.14

2.56

2.52

1.06

.77

.89

79

.98

3.23

2.05

1.73

Run-off.

Depth 

(inches).

21.11

26.71

30.62

30.81

23.95

29.15

22.09

27.51

24.91

18.25

23.88

23.65

25.10

3.89

1.50

1.32

2.86

2.91

1.28

.89

1.03

.88

1.13

3.60

2.36

23.65

Relation 

to rainfall 

(per 

cent).

56.2

56.6

69.9

71.4

55.6

60.6

51.5

54.7

52.6

45.6

51.0

60.4

57.0

93.9

51.4

89.6

102.4

119.7

40.0

25.0

12.8

47.8

24.0

69.3

72.0

54.3

Rainfall 

(inches).

37.70

46.71

43.85

43.24

43.07

48.18

42.92

50.20

47.24

40.02

46.93

45.15

44.53

4.14

2 92

1.47

2.79

2.43

3.20

3.56

8.06

1.84

4.72

5.20

3.29

43.62

Discharge and run-off of Housatonic River at Gaylordsville, 1901-1903 and 1906. 

[Drainage area, 1,020 square miles.]

Date.

1901............................

1902............................

1903............................

1906.

May............................

July............................

Discharge (second-feet).

Maximum.

14,300 

31,000 

, 25, 700

3,170 

4,630 

10,000 

8,930 

5,060 

2,370 

2,120 

1,310 

876 

2,220 

1,980 

1,440

10,000

Minimum.

303 

525 

550

938 

788 

1,130 

2,460 

1,090 

928 

421 

347 

296 

296 

550 

686

296

Mean.

2,216 

2,920 

3,006

1,800 

1,630 

2,910 

4,780 

2,110 

1,630 

984 

818 

554 

861 

992 

958

1,670

Run-off.

Per 

square 

mile 

(secondfeet).

2.861 

2.946

1.76 

1.60 

2.85 

4.69 

2.07 

1.60 

.965 

.802 

.543 

.844 

.973 

.939

1.64

Depth 

(inches).

29.65 

38.62 

39.65

2.03 

1.67 

3.29 

5.23 

2.39 

1.78 

1.11 

.92 

.61 

.97 

1.09 

1.08

22.17

Relation 

to rainfall 

(per 

cent).

52.1 

62.9 

69.8

84.2 

65.5 

81.0 

142.5 

42.6 

31.8 

17.2 

29.3 

17.0 

24.1 

80.1 

28.1

47.9

Rainfall 

(inches).

56.94 

61.43 

. 56.85

2.41 

2.55 

4.06 

3.67 

5.61 

5.60 

6.47 

3.14 

3.58 

4.02 

1.36 

3.84

46.31
30 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

POPULATION AND INDUSTRIES.

The physiographic division of Connecticut into highland and lowland areas has been a controlling factor in determining the settlement 

and character of life of the people of the State. The bulk of the 

population at the present time is grouped in three areas:

First, the central lowland, containing the towns of New Haven, 

Hartford, Middletown, New Britain, Meriden, etc., in which 39 per 

cent of the entire population of the State is located. This region was 

first settled in 1637 and the population has increased gradually from 

that date. The favorable conditions of the lowland area are the fertile soil, which is readily tilled, and the ease of establishing lines of 

communication by wagon roads, canals, and railroads.

Second, on the shores of Long Island Sound, where are located Norwalk, Stamford, Bridgeport, New London, and other towns, which 

together have a population of 199,719, or 22 per cent of the total.

Third, in the highland valleys, where Waterbury, Winsted, Willimantic,-and many smaller towns are located and where 26 per cent 

of the population reside. The original attractions of these places were 

the water power and ease of communication along valleys. Collinsville is typical of many small villages that have been built up about a 

factory whose location was determined by excellent water power.

The towns of the State outside of these three groups have attracted 

but 13 per cent of the population. The soil is thin but of fairly good 

quality. The roads have steep grades and are difficult to maintain. 

Railroad lines enter the highlands only along the wider valleys and 

are at an inconvenient distance from many of the towns. Parts of 

Union, Hartland, and North Stonington are 10 miles from any railroad, and many farms in Killingworth, Salem, Goshen, Ashford, 

Canterbury, and Ledyard are nearly as inaccessible. The result is 

that the population of certain hill towns has actually decreased. 

During the decade from 1890 to 1900 ten towns out of twenty-six in 

Litchfield County showed a decrease in population and ten out of 

thirteen towns in Tolland County suffered a net loss in population of 

1,400. At the present time a new era seems to be dawning for rural 

Connecticut, partly as a result of improved methods of farming and 

of the introduction of the practice of scientific forestry, but more 

largely owing to the fact that the farms of the highlands are being 

purchased for summer homes and estates. For this purpose an 

abundant supply of good water is essential. In fact, the water resources of Connecticut form one of its chief commercial assets, and a 

knowledge of their character and occurrence has become a matter of 

great practical importance.
CHAPTER II.

GEOLOGY.

OUTLINE OF GEOLOGIC HISTORY.

Very little is known of the early geologic history of Connecticut. 

It is probable that some of the gneisses and schists date from a time 

before any living forms existed upon the earth, but no fossils older than 

the Triassic have been found in the State, and it is therefore impossible to determine definitely to what age the pre-Triassic rocks belong. 

Their position in the time scale can, however, be determined approximately by comparing them with similar rocks in regions where their 

relations are known. This study of adjoining regions, taken in connection with the detailed study of the structure of the rocks themselves, indicates that the crystalline rocks of Connecticut have a 

long and complicated geologic history.

Pre-Cambrian rocks are represented in the State by the Becket 

gneiss, but no data are at hand to determine definitely the origin or 

age of this formation. Its component parts have been so completely 

altered by changes that have taken place since their deposition that all 

evidence of value for determining their original character has been 

destroyed. The character of the rocks overlying the Becket gneiss 

indicates that a sea extended over a large part of Connecticut during 

Cambro-Ordovician time and that the Stockbridge limestone and 

associated quartzites were deposited in that ancient water body. 

Such an accumulation of material implies the wearing down of land 

masses and suggests that lands of considerable elevation must have 

existed to the east of the present shore line.

The long interval between the close of the Ordovician and the beginning of the Mesozoic time has left no legible records of deposits that 

can be assigned to any definite geologic period. The great thickness of Devonian sediments to the west suggests a New England 

mountain range of considerable height which furnished material for 

the sedimentary strata.

One series of events, however, is abundantly attested, namely, 

that igneous intrusions occurred frequently in the interval between 

the Ordovician and the Triassic periods, resulting in the formation of 

numerous veins and dikes of quartz and granitic and basic rocks. 

The nature of these intrusive masses indicates that they have been

31
32 UNDERGROUND WATER EESOUECES OF CONNECTICUT.

brought to the surface by the removal of thousands of feet of sediments. The particular date of any of these igneous intrusions is 

unknown, but their effect is well shown, and it is not at all unlikely 

that part of the molten rock reached the surface and was represented 

by volcanic activity, afl traces of which have disappeared.

The geologic records show also that at different times between the 

Ordovician and the Triassic there were important movements in the 

earth's crust which resulted in the metamorphism of all the existing 

rocks in the State. Just when these profound changes took place is 

unknown, but the rocks are believed to have been involved in the 

great earth movements which produced mountains at the close of the 

Archean, Ordovician, and Carboniferous periods.

That many changes took place in Connecticut during the time from 

the Ordovician to the close of the Carboniferous is shown beyond 

doubt by an examination of the highland areas.

These rocks are chiefly schists and gneisses, and accordingly have structures indicating that they have been profoundly changed from their original sedimentary or 

igneous character. The original component minerals have been rearranged, stretched, 

and drawn out in lines; new minerals have been produced; parts have been fused and 

recrystallized. Instead of horizontal layers or uniform igneous masses, we find 

twisted and broken rock with layers, bands, and ribbon structures in every conceivable position. This tangle of structure is further complicated by the presence of dikes, 

seams, and veins which have made their way into the rock at different stages of its 

history. In looking at this confused mass of rock which forms the Connecticut crystallines, it seems apparent that it has taken part in manifold changes which went on in 

the earth's crust for ages. This very complexity of structure is an important aid in 

determining the relative age of the rocks, for it is evident that in general the oldest 

rocks must have been affected by the greatest number of disturbances, and accordingly the rocks of one age may exhibit structures not found in those of succeeding 

ages. In the absence of other criteria the geologist is forced to fall back upon this. 

These rocks are like a parchment on which writing after writing has been placed at diferent times by different hands, without at any time completely erasing the previous 

inscriptions. Little wonder that we have difficulty in deciphering the original writing.

Such composition and structure as is described above can be produced only at very 

great depths in the earth (probably below 20,000 feet) where rocks are so deeply buried 

that, whatever the lateral stress, they will not adjust themselves by breaking, but by 

plastic deformation. It is therefore certain that, whatever the age of the crystallines, 

mountain ranges perhaps rivaling the Alps in height and ruggedness once occupied 

central Connecticut; and when we examine the rocks of Satans Kingdom, or the Quinnebaug Valley, or the Connecticut gorge below Middletown, or indeed any part of the 

area of crystalline rocks, we are studying the roots of lofty land masses composed of 

strata deposited during part or all of the Paleozoic era. 0

The land at the close of the Carboniferous was probably marked by 

rugged topography the hills and valleys making prominent scenic 

features. During Triassic time these elevations were removed and 

the material from the crumbling hills was built into the sandstones 

of central Connecticut.

a Rice, W. N., and Gregory, H. E., Manual of Connecticut geology, 1906, pp. 80, 81.
GEOLOGY. 33

The Triassic rocks are very much younger than any of the crystalline rocks exposed within the State; in fact, it is possible that no 

rocks were formed for a long period before the deposition of the 

lowest sandstone stratum. Where the ancient crystalline rocks and 

the Triassic rocks come into contact there is a marked unconformity, 

the sandstones lying upon the upturned edges of schists and gneisses 

of ancient time. The Triassic sandstone was deposited in water 

which was fresh or perhaps brackish, and a great deal of it was 

deposited in water which must have been shallow. The presence of 

animal life is indicated by the fossils found in the sandstones and 

shales. Skeletons of dinosaurs have been recovered and thousands 

of tracks of these strange animals have been found in the quarries of 

the Connecticut Valley. The shales at Saltonstall and Durham and 

elsewhere contain abundant remains of fish.

During the long time throughout which the Triassic sediments 

were being deposited volcanic eruptions formed widespread lava 

flows extending from New Haven to the northern line of the State. 

Outbursts of lava occurred at three different times and the fields of 

basalt which represent these flows are separated by considerable 

thicknesses of shale and sandstone, indicating periods of volcanic 

activity followed by long periods of quiet.

The sandstones and lavas of Connecticut were laid down in an 

approximately horizontal position, but at a date later than the 

Triassic the flat-lying beds were broken by a series of faults extending 

diagonally across the central lowlands. Displacement along these 

fault lines formed a series of giant blocks, composed of sandstone and 

trap, that were elevated on the west side and depressed on the east. 

The topographic result was a series of ridges with steep westward 

escarpment and gently sloping eastward face.

During Cretaceous time the entire region seems to have been worn 

down to a plain practically at sea level and sloping gently from northwest to southeast. Hills stood above the plain, but not to such an 

extent as to give the country a rugged topography. The southern 

part of the State at this time was probably covered with sediments 

deposited in a Cretaceous sea which extended to the latitude of 

Hartford. The result of this long period of erosion was to reduce the 

inequalities produced by the uplifting of the blocks of sandstone and 

lava and to lessen the contrast between highland and lowland areas.

Near the beginning of the Tertiary period the area now forming 

the State was uplifted and the streams which had been wandering 

across the Cretaceous plain were revived and began once more to cut 

their channels and to carry sediment to the sea. The result'was to 

bring into relief all the harder and more resistant rock masses by 

removing the softer material. For example, in central Connecticut 

the areas of resistant trap stand above the sandstone plain as ridges 

463 IRR 232 09 3
34 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

whose length and shape had been previously determined by the 

direction of the fault lines. In the same way the softer Cretaceous 

strata along the coast seem to have been entirely removed and the 

less resistant limestone of the Housatonic Valley reduced to a narrow 

lowland. As a result of this long period of stream erosion during 

Tertiary time, the topography of the State acquired the larger general 

features of the present time.

During the Pleistocene (" Glacial") epoch the topography of 

Connecticut was again remodeled. The continental ice sheet which 

covered the northern part of America extended entirely across New 

England. Its thickness was great, the power urging it on was irresistible, and accordingly the landscape was molded in a characteristic 

manner. The loosened soil covering was removed from the rocks and 

the rocks themselves were reduced in height. They were grooved 

and scratched and polished by the pebbles embedded in the ice. A 

great quantity of material was removed permanently from the area 

and carried to Long Island. Although the larger features of the 

topography left by Tertiary erosion were little changed when the 

glacier disappeared, the details were greatly modified. Instead of the 

soil formed by the decomposition of the rocks, the glacier left two 

types of surface covering glacial till, an unassorted and unstratified 

mass of rocks, bowlders, clays, and sands, differing widely in size and 

in composition, and stratified drift composed of layers of sands 

and gravel. The till came directly from the material carried by the 

glacier. The stratified drift was deposited by the waters from the 

melting ice mass. The distribution of this glacial material over the 

entire region modified the shape of hills, filled valleys, blocked 

drainage courses, rearranged stream channels, and left many depressions filled with bodies of water, so that although the main streams, 

like the Connecticut and the Housatonic, are now flowing in courses 

inherited from Tertiary time, yet the smaller streams owe their 

present arrangement very much to the changes produced by glaciation. Waterfalls, lakes, ponds, and swamps are also records of the 

Pleistocene ice invasion.

DESCRIPTIVE GEOLOGY.

INTRODUCTION.

The occurrence of ground water and the methods of its recovery 

are determined by the structure of the rocks, and therefore a knowledge of the character of the geologic formations of a region is essential to the well driller and to 'the well owner if he desires to attain 

satisfactory results at minimum expense. In Connecticut a well in 

mica schist may need to be of different construction from one in 

sandstone and will yield water differing in amount and in quality. 

Wells in till are usually shallow and of large diameter; those in
GEOLOGY. 35

stratified drift are particularly liable to contamination; those in 

sandstone and shale rarely yield water that is suitable for boilers. 

Thus in many ways the rock formations represented in the State 

determine the nature and value of the water supply.

In Connecticut three widely different rock groups must be taken 

into account by the well driller the crystalline rocks forming the 

western and eastern highlands; the sandstones of the central 

lowland; and the deposits of sands, gravels, and clays which overlie 

all the rocks of the State. The sandstones, shale's, and conglomerates are of Triassic age, as is shown by the numerous fossils contained in them. The gravels and other surficial deposits are of 

Pleistocene age. The crystalline rocks are of much greater antiquity, 

but owing to the absence of any definite marks of identification 

they will be referred to simply as pre-Triassic.

CRYSTALLINE ROCKS. 

DISTEIBUTION AND CHAEACTEE.

With the exception of the area underlain by Triassic strata, the 

entire State of Connecticut is occupied by crystalline rocks of very 

great age. They are of two types, igneous and metamorphic, both 

widely different from the sediments of the valley lowlands.

Igneous rocks are those which have been molten and have solidified from cooling. They are accordingly composed of crystals, 

closely fitted and interlocking, instead of being made up of grains or 

fragments of material, as are sandstones. The many different 

textures shown by these igneous rocks were determined by their 

rate of cooling, and in accordance with this principle fine-grained 

granites and granite porphyry have been formed. Unchanged 

igneous rocks are rare in Connecticut outside of the traps of the 

Triassic region. They occur as veins, dikes, and small bosses, 

mostly of granite and related rocks. A few diabase dikes are distributed along the borders of the lowlands. The masses of unaltered 

igneous rock within the ancient crystalline areas are so small that 

it has not been found desirable to indicate them on the geologic 

map of the State. a

Metamorphic rock constitutes practically all of the crystalline 

areas in Connecticut. Rocks of this type have been profoundly 

changed from their original condition either as igneous or sedimentary. The change in some of these rocks is merely a hardening, as 

when shales are baked by the intrusion of a trap dike. But the 

metamorphic rocks of the State as a whole show much more complete 

alteration. Their mineralogical composition has been changed, 

their structure has been destroyed, and fossils which they may

o Bull. Connecticut Geol. and Nat. Hist. Survey No. 7,1907.
36 ITNDEEGBOITND WATEE EESOUECES OF CONNECTICUT.

have formerly contained have been obliterated. The changes have 

been so great that the rocks bear little resemblance to their former 

appearance, and with some of them it is impossible to determine 

whether the original material was igneous or sedimentary.

The metamorphic rock masses existing within the State are 

crystallized limestone (marble), quartzite, phyllite, schist, and 

gneiss. Marble is a metamorphosed limestone, in which the grains 

of the original rock have been converted into crystals. Quartzite is 

a sandstone which has been made firm and compact by filling in the 

spaces between the sand grains with quartz. Phyllite is usually an 

advanced stage in the development of slate, which in turn is made of 

mud shales and related rocks. Schists and gneisses are so widespread 

within the State that they might be said to constitute the bed rock 

of the region. Twenty-three varieties of gneiss and eight varieties 

of schist are shown on the Connecticut geologic map. Schist is a 

term used to indicate the structure of the rock, not its composition, 

and represents an extreme stage of metamorphism in a rock which 

may have been originally igneous, sedimentary, or metamorphic. 

In schists so far has metamorphism proceeded that new minerals 

have been made, particularly mica, and a complete rearrangement 

of the mineral particles has taken place.

The value of the crystalline rocks as water carriers is determined 

by the facts that they are very dense, nonpermeable rocks, that 

structures of slatiness and schistosity are developed in them, that 

they are traversed by numerous joints in many directions, and that 

they are cut by large or small faults.

Schists are characterized by cleavage planes which enable the 

separation of the rock into irregular layers of small thickness. The 

structure which admits of the splitting of the rock in this manner is 

called schistosity and owes its origin to the parallel arrangement of 

micas and other flat minerals whereby separation takes place in one 

direction much more readily than in others. Schists always contain 

an abundance of mica, but they contain also other minerals in large 

amounts. Feldspar is invariably present, and a typical mica schist 

consists essentially of feldspar, mica, and quartz. The names hornblende schist, quartz schist, kyanite schist, etc., used in the following 

pages, indicate the prominence of certain minerals. Most of the 

Connecticut schists are believed to be the metamorphic equivalents 

of sedimentary rocks, the Hoosac ("Hartland") schist, for example, 

having previously been a series of sandstones, shales, and limestones, 

much like the present sediments of the Triassic belt.

Gneiss, like schist, is a terra which refers only to the structure of a 

rock and implies the existence of a series of roughly parallel breaking planes along which the rock may be separated into slabs of various 

sizes. The development of schistosity is alike in gneisses and schists,
GEOLOGY. 37

but gneiss is more massive and is commonly the present equivalent 

of former igneous rocks. The production of gneiss from granite has 

taken place within the Connecticut area on a large scale. Granite 

masses have been stretched and squeezed so that instead of being of 

uniform texture and massive structure they are drawn out into 

sheets and definite layers. Practically all of the granite quarried 

within the State is granite gneiss, the gneissoid structure of which 

is an important factor in successful quarrying.

When schists or gneisses are exposed to the atmosphere the planes 

of schistosity often become definite cracks and open fissures into 

which water may descend and collect in amounts sufficient to supply 

wells or springs. It is this capacity to carry water which makes a 

detailed study of the structure of rocks a matter of practical importance.

JOINTS.

Rocks do not as a rule present an unbroken surface over any considerable area, but are traversed by cracks, which vary in size from 

those that are scarcely visible to those that are several inches in 

width. These cracks or "seams," as they are called by drillers and 

quarrymen, are technically joints. They are the results of mechanical action in rocks, which breaks them into more or less regular 

polygonal blocks separated by open spaces, and they are therefore 

of great importance when water-storage capacity is considered.

The most common type of joints includes those which are approximately vertical and cross each other at various angles, giving the 

rock surface the appearance of a rough screen or network. The prevalence of vertical jointing is shown by the fact that the inclination 

of about seventy-five measured joint planes in the Connecticut 

crystalline rocks was found, to average 74°, forty of the joints being 

practically 90° from the horizontal. Another set of joints in the 

crystalline rocks runs more or less parallel to the surface of the rock. 

Some of these joints correspond to gneissoid and schistose structures, 

but many others represent entirely different planes of cleavage. In 

the gneissoid granites, as at Maromas and Glastonbury, these horizontal joints occur, but they vary considerably in their extent, number, spacing, and direction, as well as in width of opening, a variation 

which seems to depend primarily on the character of the rocks which 

they traverse. In the gneisses, particularly in gneissoid granites 

and granodiorites, the horizontal joints are very well developed and 

constitute the so-called "bedding" of the quarrymen. In the schists 

and the less massive gneisses horizontal jointing is poorly developed 

and in places even lacking. The character and number of vertical 

joints also depend on the nature of the rock. Certain rocks seem to 

be thoroughly shattered and broken by vertical joints into small
38 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

wedges and blocks a fraction of an inch in diameter. Other rocks, 

like pegmatites, may extend for 25 to 50 feet without being marked by 

a prominent line of breaking. A good illustration of the difference 

of the jointing in two types of rock is seen in the Milford chlorite 

schist, where much fractured schistose and slaty varieties occur 

immediately in contact with fairly compact masses of altered diabase.

FAULTS.

Fractures along which, more or less vertical movement has taken 

place are called faults and have been frequently observed in outcrops 

of crystalline rock. Many of the fractures extend to considerable 

depths and may appear on the surface as single lines or as zones of 

closely packed joints or of shattered rock. Much ground water may 

be stored in zones of faulted rock, and the open spaces afforded for 

the movement of water make fault lines of great value as channels for 

spring waters and supplies for wells.

TRIASSIC SANDSTONE AND TRAP. 

DISTRIBUTION.

The Triassic rocks of the State occur in two areas one extending 

from the Massachusetts line to Long Island Sound, with a breadth 

of about 20 miles at Thompsonville and narrowing at New Haven 

to the width of the harbor, the other underlying the towns of Southbury and Woodbury. Both of these areas are links in a broken 

chain, of similar Triassic deposits which extends from North Carolina 

to Minas Basin, on the Bay of Fundy, a distance of 1,200 miles, and 

which covers altogether 10,000 square miles.

STRATIGRAPHY.

The relation between the Triassic strata and the ancient crystalline 

rocks is seen at Roaring Brook, in Southington, where sandstone lies 

unconformably upon the upturned edges of the Hoosac ("Hartland") 

schist. A general study of the Triassic areas of the Atlantic coast 

leads to the belief that the Connecticut areas are parts of a much 

larger expanse of Triassic rocks and that they owe their .present 

existence to the fact that they have been dropped down as a result 

of faulting, and thus protected from the erosion which removed the 

adjoining areas exposed at higher levels.

The rock types existing in the Triassic area are two the lavas 

(basalts) and intrusive sheets and dikes (diabase), rocks which are 

called popularly "trap;" and the sandstones, which range in texture 

from fine shales to extremely coarse conglomerates. The stratigraphic series in the Triassic of Connecticut consists of three lava
GEOLOGY. 39

flows with sedimentary strata below, between, and above them. 

Their relations are shown by the following table:

Stratigraphic succession in Triassic rocks of Connecticut.

Pre-Triassic metamorphic rocks. Feet.

"Lower" sandstones................................ 5,000-6,500

"Anterior"a (lower) trap............................. 250

"Anterior " shales and shaly sandstones.......... t ... 300-1,000

"Main" (middle) trap............................... 400-500

"Posterior" shales.................................. 1, 200

"Posterior" (upper) trap............................. 100-150

"Upper" sandstones................................ 3, 500

The "Lower" sandstone varies in texture from a fine-grained 

rock in the vicinity of Avon and Granby to a coarse conglomerate 

in which some of the pebbles exceed 2 feet in diameter. Where 

typically exposed in the quarries at Fair Haven the rock consists 

of fragments from the bordering crystalline rocks, including abundant 

crystals of feldspar, pebbles of quartz, fragments of porphyries, 

gneisses, and schists. Great variation is shown in the composition 

and structure of the beds, and abrupt changes in the character of the 

rock are observed at many places. In general the stratification is 

uneven and irregular, and the coarser and finer materials have 

rather the character of lenses than of uniform beds of wide extent.

The "Anterior" and "Posterior" sandstones contain a much 

larger proportion of shales than the "Lower" sandstones; in fact, 

shales and shaly sandstones are characteristic of these formations. 

In certain places, as east of Southington, an impure limestone occurs, 

and in a number of localities there is a slightly bituminous black 

shale. The stratigraphic position of the black shale is 50 to 100 

feet above the "Anterior" trap sheet and at different levels between 

the "Main" and "Posterior" traps. The presence of these beds of 

shale has an important bearing on the problem of water supply. 

(See p. 109.) Fossil fish have been discovered in them at Saltonstall 

Lake, Rocky Hill, Durham, and other localities.

The "Upper" sandstones, consisting of sandstone and shale, with 

conglomerate locally developed, constitute the Triassic strata east 

of the central trap ridge. It is in these sandstones that the quarries 

at Portland and Long Meadow are located. In certain localities the 

"Upper" sandstone has characteristic features, but as a rule it 

is not a distinct formation. As stated by Davis,6 "the Anterior, 

Posterior, and Upper sandstones and shales are seldom distino Owing to the monoclinal faulting which has broken the Triassic strata into eastward-tilting blocks, 

the traveler going from west to east across the Connecticut lowland comes first to the lowest and 

oldest lava flow, next to the middle, and last to the uppermost. Hence the terms "Anterior,^' 

"Main," "Posterior," first used by Percival.

6 Eighteenth Ann. Rept. U. S. Geol. Survey, pt. 2,1898, p. 139.
40 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

guishable." It is also true that these three formations are practically indistinguishable from the "Lower" sandstones.

The three lava flows "Anterior," "Main," and "Posterior" 

are identical in chemical and mineralogical composition and are 

manifestly of closely similar origin. They are flows of basalt from 

unkkown sources. The "Anterior" trap is broken into a series of 

small hills and short ridges at Saltonstall, Totoket Mountain, Lamentation Mountain, and other places, and disappears in the vicinity 

of "Newgate Prison/' in East Granby. This trap sheet is comparatively dense, but is vesicular on the upper surface, and at Lamentation Mountain it contains an "ash bed" of fine lapilli, 30 feet thick. 

The "Main" trap sheet is made up of two or more flows with a 

combined thickness of 400 to 500 feet and constitutes the most 

prominent topographic feature of central Connecticut, forming the 

conspicuous ridges beginning at Saltonstall and extending through 

Meriden and Farmington and into Massachusetts, where they include 

Mount Tom and Mount Holyoke. The "Posterior" trap follows the 

"Main" trap sheet in general alignment and has similar characteristics, but at only a few places does it become an important topographic feature. An excellant view of the "Posterior" trap and 

the underlying sandstones may be obtained at the city quarry, 

Hartford, immediately adjoining the buildings of Trinity College.

In addition to the three lava flows there is a series of intrusive 

trap sheets and dikes composed of diabase. East and West rocks 

at New Haven, Gaylord Mountain, the ridges east of Canton, and 

the Barndoor Hills are examples.

JOINTS.

Both the sandstones and the traps of Connecticut are traversed 

by many prominent joints, which form reservoirs for ground water. 

Where exposed in quarries the sandstone is seen to be cut by numerous 

joints and open fissures, so that even in the most favorable localities 

it is impossible to quarry slabs of stone of very large size. The 

principal joints are nearly vertical and intersect each other at fairly 

wide angles, so that the finer-grained sandstone and the shale break 

in more or less uniform blocks. In the Hartford quarry the shale is 

traversed by two prominent sets of cracks, which enable the workmen 

to remove diamond-shaped blocks about a foot in diameter. The 

conglomerate, especially where it contains large quantities of quartz, 

exhibits much less uniformity in jointing than the finer-grained rocks. 

The blocks into which it breaks are wedges and rude polyhedrons of 

such a variety of form as to make it impossible to predict the location 

of definite division planes. Many of the joints in the sandstone are 

weathered to great depth and furnish ready passage for water. (See 

pp. 73-74, 111-113.)
GEOLOGY. 41

The trap rocks are of such uniform texture and of such fine grain 

that the jointing is exhibited on a very; elaborate scale. Usually the 

joints are barely visible, but in a few places they are widely open and 

some of them have been filled with secondary material. The intrusive traps, and some of the lava flows as well, show a decided jointing at right angles to the plane of cooling, which gives a rudely 

columnar structure to the rock. In the New Haven region the 

columns are .beautifully developed at Rabbit Rock, and some of the 

dikes in the Fair Haven tunnel show a regular and uniform system of 

joint cracks.

Perhaps the most convincing evidence of the abundance and influence of joints in trap is furnished by exposed cliffs below which 

is a talus slope of broken trap formed by joint blocks derived from 

the ledge above. Practically every high trap ridge in the State is 

flanked by such jumbled masses of fragments, the size and shape of 

which is determined by the direction and spacing of the cracks in 

the ledge. On the exposed edges of cliffs the joints furnish ample 

facilities for the free circulation and storage of water. In fact, where 

the bed rock is trap these cracks contain almost the,only water supply 

within reach of wells.

FAULTS.

The sandstones and lavas of the Triassic area were laid down in a 

horizontal position. They no longer retain that attitude, however, 

but dip to the east at an average angle of 15° to 20°. In a few places 

the strata lie practically flat, and locally the dips are as high as 40°. 

These dips are due to the fact that the region is crossed by a series of 

fault lines which have cut the strata into blocks that are tilted to the 

east. Faults are joints or cracks in rock along which movement has 

taken place and which, accordingly, disturb the continuity of the 

rock much more profoundly than simple joints. In the lowland area 

twenty-five faults have been traced which extend for 5 miles or more, 

and one fault extending between Hanging Hills and Lamentation 

Mountain extends northeast and southwest for 40 miles. Innumerable smaller faults exist and may be observed in practically every 

outcrop of trap or sandstone. In places they occur so abundantly 

and are so closely placed that the rock appears to be shattered into 

small fragments. The amount of slipping which has occurred along 

these fault planes varies from a few inches, observed in quarries and 

railroad cuts, to several thousand feet in the great diagonal faults 

which have brought the "Lower" sandstones of Lamentation Mountain up to the level of the "Posterior" trap. The uplift in most of 

these faults is on the east side of the fault line, which accounts for 

the eastward dip of the strata and for the westward-facing cliffs. If 

the faults extended in the direction of the strike of the strata a series
42 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

of parallel ridges would be exposed, marked by prominent cliffs of 

erosion on the west side. But the faults have traversed the formations obliquely, most of them from northeast to southwest, with the 

result that the erosion has produced a series of blocks which are not 

in alignment but are offset to one side or the other and separated by 

passes and gaps and notches.

The small Triassic area in the Pomperaug Valley presents features 

practically identical with those in the central lowland, and therefore 

requires no separate description.05

PLEISTOCENE DRIFT. 

DISTRIBUTION AND GENERAL RELATIONS.

The glacial deposits of Connecticut form a mantle covering the 

bed rock practically everywhere. It is doubtful if bare rock is 

exposed over one-tenth of 1 per cent of the surface. The drift in 

thickness varies from a mere film to masses 300 feet in depth which 

have obliterated ancient stream courses. It is not quite so thick 

near the Sound and on the highlands as in the major valleys, and the 

rock ledges are confined for the most part to the summits of ridges 

and projecting cliffs now partly covered with talus. The disintegrated rock material formed throughout earlier geologic ages wTas 

removed by the glaciers, so that in general the rock surface where 

exposed is firm. Immediately overlying the solid rock, but with a 

marked unconformity between, is the glacial drift. The surface 

material as a rule has not originated from the rock on which it rests, 

and it may be entirely different in composition as well as in texture. 

Drift fragments of gneiss may be in immediate contact with shale, 

and bowlders of sandstone and trap may form the soil above ledges 

of mica schist. The fact that the bed rock is everywhere covered 

with glacial drift is one of the most important factors in the underground water problem of Connecticut, for the drift acts as a reservoir to feed water into the joints and cracks of the bed rock underneath. (See p. 142.)

CHARACTER OP MATERIAL.

Two types of glacial material are exhibited in the State till and 

stratified drift. The till was made directly by the glacier and 

consists of deposits which are characteristic and quite unlike those 

made by water or wind. Glacial ice does not sort material, and the 

result is that till is composed of bowlders, sands, clay, and pebbles 

of all sizes, confusedly intermingled; and the same outcrop may 

show a heterogeneous lot of bowlders mixed with finely ground

"For a complete discussion of the faults of the Woodbury-Southbury region see Hobbs, W. H., Twentyfirst Ann. Kept. U. S. Geol. Survey, pt. 3, 1901, pp. 7-162.
GEOLOGY. 43

clay and sand. The bowlders may be securely bedded in rock flour 

in such a manner as to form "hardpan," which is scarcely less friable 

than artificial concrete and which furnishes little access to water; or 

the whole mass may be composed of bowlders and sand with large 

spaces between the fragments. Ordinarily the till is spread more 

or less uniformly over a region with a thickness depending on the 

character of the underlying topography, but here and there it is 

built into mounds (drumlins) which have been overridden by the 

ice, much as sand bars are formed in rivers.

Most of the rock fragments composing the till have not been 

rounded by water, and although much worn they are subangular and 

in many places polished and grooved and striated. The innumerable 

bowlders strewn over the surface of the State, built into fences, or 

used for foundations are parts of the till left by the retreating glacier.

Stratified drift consists of rounded fragments of sand and gravel 

deposited by water from the melting ice and differs little in appearance from deposits made by rivers or by the ocean. It differs from 

till in being stratified that is, it is arranged in layers of fine and 

coarse material; and although the original fragments are the result 

of the grinding action of the ice sheet, the present position and structure of the drift are due to glacial waters. Stratified drift usually 

forms sand plains, and is confined chiefly to valleys and lower levels. 

Certain long winding ridges of stratified drift, indicating the channels 

of preglacial streams, are called eskers, and in some places the 

stratified drift takes the form of knobs, short ridges, and kettle 

holes, which are due to water action under conditions of confinement.
CHAPTER III. 

OCCURRENCE AND RECOVERY OF GROUND WATER.

CIRCULATION OF GROUND WATER.

THE WATER TABLE.

The term "ground water; ' is used in referring to water supplies 

obtained from wells or springs, in contrast with those derived from 

streams and lakes. The ground water represents that part of the 

rain or snow which penetrates into the soil, while the remainder of 

the precipitation is delivered directly to surface streams, evaporated, 

or absorbed by vegetation.

The clearest conception of the circulation of ground waters may 

be obtained by considering the material in which they occur to be of 

a uniform character. Every one is familiar with the fact that a hole 

dug in the sandy beach of the sea or of a lake will fill with water to 

the level of the sea or lake water, and in a sea-beach hole the level of 

the water will lower as the tide goes out. As holes or wells are dug 

at greater distances from the shore and at higher elevations the level 

of the water in the wells is found to rise above that of the surface of 

the lake, river, swamp, or other body of water with which the comparison is made. The height to which the water will rise at any 

point in the ground is known as the height of the water table at that 

point. The water table therefore represents the upper limit of a zone 

saturated with water, above which the ground is relatively free from 

water except immediately after rainfall. It is the surface of the sea 

of ground water, and it is also called the "ground-water level."

The water table has a surface rising and falling with the land surface, but with smaller differences of elevation. The water has the 

highest elevation on the hills and the lowest in the depressions, but 

stands farthest from the surface of the ground on the hills and rises 

nearest to the surface in the depressions; where these are deep enough 

it reaches the surface to form swamps, lakes, and streams. Where 

the ground is perfectly level and uniform in character the level of the 

water table is uniform, but where changes occur in the surf ace elevation 

the water flows from the higher to the lower points, and there is thus 

a constant movement of the ground water from the hills toward the 

valleys. With surface waters this movement is unrestrained and the 

water immediately runs off the hills; but the movement of ground 

waters is very slow, owing to the frictional resistance to the passage

44
OCCTJKKENCE AND EECOVEKY OF GEOTJND WATEE. 45

of the water through the small openings of the soil and rock. This 

slowness of movement makes possible the existence of shallow dug wells 

on hills, and it is also the cause of the constancy of flow of streams 

and springs throughout the year. If the ground water moved as freely 

as the surface water the streams would have exceedingly large flows 

immediately after heavy precipitation and would be dry in the intervals between rains.

MOVEMENT OF GROUND WATER.

The movement of ground water is due to the force of gravity, and 

accordingly tends to take a vertical direction. After a rainfall the 

water absorbed by the ground gradually percolates downward 

through the soil until it reaches the water table, where the motion of 

the sea of ground water instead of being vertical is mainly in the 

same direction as the slope of the surface. This slowly moving body 

of ground water finally comes to the surface. Some of it emerges as 

springs or as a succession of small seepages along the banks of streams, 

but a considerable proportion of it probably enters streams and lakes

FIGURE 5. Diagrammatic section illustrating seepage and growth of streams. Lines with arrows are

lines of flows.

below the water level. The general directions of flow of ground 

water and the manner in which streams are supplied are indicated in 

figure 5.

Although the circulation of ground water is in a general way as 

stated above, it happens that natural conditions rarely afford a uniform material in which the level of the water table may be predicted 

at any point. The ground is nearly everywhere made up of materials varying in character and offering different degrees of resistance 

to the circulation of water. In Connecticut the ideal conditions are 

most nearly realized in some of the flat sandy plains of the Connecticut Valley.

POROSITY.

The circulation of water in any material is directly dependent on 

the amount and character of the openings in that material, and these 

openings may be in the form of small pores, of long flat joints or 

other'fractures, or of irregular rounded and tubular openings varying 

in size.
46 UNDEKGKOUND WATEB KESOURCES OF CONNECTICUT.

All rocks are composed of masses of separate particles or grains 

which do not touch each other at all points, small irregular openings 

occurring between the grains. This pore space, called " porosity," 

varies greatly in different materials and is largest in rocks that are 

composed of rounded grains laid down under water and least in rocks 

that have solidified from a molten condition. The porosity of a rock 

is expressed as a percentage of the entire volume. If 100 cubic feet 

of sandstone can absorb 20 cubic feet of water the rock is said to have 

a porosity of 20 per cent.

The following table gives the percentage of pore space and the 

amount of water absorbed per cubic foot by various sorts of rocks:

Porosity of different rocks.

Rock.

Do..........................................................................

Do................ ........................

Do..........................................................................

Do. .........................................................................

Do. ............................... .... . . ................................

Chalk. . .........................................................................

Sand............................. . . . ..................................

Clay............................................................................

Percentage of 

pore 

space.

4.81

28.28

.14

13.36

.184

3.578

.099

.304

Water 

absorbed 

per 

cubic foot 

(quarts).

2-6

i-lj

1-5

T*5-i

4-8

8-10

10-12

These figures represent the ordinary limits of the porosity of the 

rocks and are derived from different sources.

PERMEABILITY.

The permeability of a rock is a measure of its ability to transmit 

water and is the most important factor in determining its value as a 

source of water supply. Permeability is dependent on the amount 

and character of porosity and on the existence of other openings, 

such as joints and other fractures and the small openings formed by 

escaping gas in certain lava flows.

In order that water may readily pass -through a rock it is necessary 

that the openings be of appreciable size and have good connection 

with one another. In openings of small size the flow of water is 

strongly opposed by friction and by the attraction between the 

sides of the openings and the water, which in very small openings 

is sufficient to cause all the water to adhere to the sides as if glued. 

The effect of small size of openings is well shown by clays such as the 

brick clays of the Connecticut Valley, which may absorb water equal 

to 40 per cent of their weight, indicating a high porosity, but which 

allow water to pass through only with extreme slowness. In'clays
OCCURRENCE AND EECOVEEY OF GROUND WATER. 47

the constituent particles are so small and of such angular shape that 

the individual pore spaces are exceedingly minute, though in the 

aggregate of considerable volume. In sandstones the openings are 

so large as to allow relatively rapid flow. In general the size of the 

pores and consequently the permeability decrease with decrease in 

size of grain. Slichter a has made the following calculations, based 

on experimental work, of the velocity and amounts of ground water 

passing through materials of different grades.

Velocity of ground water in materials of different grades, pressure gradient 10 feet to the mile.

Material.

Diameter 

(millimeters).

0.2 

.4 

.8 

2.0

Distance traveled per 

year.

Miles.

0.010 

.041 

.16 

1.02

Feet.

52.8 

216.0 

845.0 

5,386.0

Flow of ground water in materials of different grades through a bed-of vertical cross section 

200 by 1,000 feet, sloping 10 feet to the mile.

Cubic feet 

per minute.

Fine sand...................................................... 5. 5

Medium sand.................................................. 22

Coarse sand.................................................... 87

Fine gravel................................................... 546

These determinations assume a uniform size of grain, a uniform 

porosity of 32 per cent, and a temperature of 50° F.

The law of flow through homogeneous porous materials is that the 

quantity of flow varies as the square of the size of the soil grain, 

other factors being constant. This law is based on the assumption 

that the grains are unconsolidated, but in all sandstones there is 

more or less cementing material which binds the grains together and 

necessarily decreases the amount of pore space. The more highly 

cemented the rock the less the porosity, although the cementation 

itself is an indication of former free circulation, as it is due to the 

deposition of mineral matter from water. Other factors influencing 

the amount of flow are variations in porosity and in temperature. b 

The flow at 70° F. is about double that at 32° F., owing to the fact 

that the viscosity of water decreases rapidly with rise in temperature.

The influence of joints and other fractures is of increasing importance as the porosity and size of the pore openings decrease, and in 

thoroughly crystalline rocks the only water circulation of consequence is through fractures. The rapidity of flow through joints is

a Slichter, C. S., Motions of underground waters: Water-Supply Paper TJ. S, Geol, Survey No. 67, 1902, 

pp. 29, 30.

6 Slichter, C, S., op. cit., p. 25.
48 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

not known, but it is undoubtedly much greater than through the 

pores. Owing to the differences in the permeability of rocks water 

has decidedly different rates and amounts of flow in adjacent materials. The main flow of water is confined to the most permeable 

formation, other conditions being equal.

Most underground waters yielding supplies of economic importance 

are under more or less modified artesian conditions; that is, they 

follow definite inclined channels or zones, inclosed by material more 

impermeable to water than that carrying the water, and rise to some 

extent above the level where they are struck.

ARTESIAN CONDITIONS.

The term artesian was originally applied only to wells which yielded 

a flow of water rising above the surface of the ground, but it is now 

frequently used for any water that will rise above the point where 

it is struck, indicating that it is under pressure or head. The ideal 

conditions for artesian circulation are two inclined layers of imperFIGURE 6. Diagram illustrating artesian conditions where water does not rise to the surface.

vious material inclosing a layer of permeable material saturated 

with water for which there is no escape below the point where the 

water-bearing material is tapped. If the upper impervious layer is 

then penetrated in some manner, as by a drill hole, so that the saturated layer is entered at some point below the level at which the water 

naturally stands, the water will rise in the drill hole to a height 

determined by and nearly equal to the level at which the water stands 

in the water-bearing material. Figure 6 represents the conditions 

under which flowing wells may occur and under which the water will 

rise under artesian pressure to a certain level, but will not reach the 

surface.

The level to which water will rise in the well will always be somewhat lower than that of the water table in the permeable material, 

owing to the loss of head due to friction during the passage of the 

water to the well, and this difference in level will increase with 

increase of distance from the source of supply.
OCCUEBENCE AND EECOVEEY OF GEOUND WATEE. 49

The conditions on which artesian flow depends may be summarized 

as follows:

1. A porous and permeable stratum capable of absorbing and 

transmitting large quantities of water. In certain localities planes 

of fracture may transmit the water rather than a porous stratum.

2. Relatively impervious materials above and below, preventing 

the escape of water from the porous stratum. Such conditions might 

be realized by a bed of sandstone between two beds of shale or by a 

layer of sand resting on massive granite and overlain by clay.

'3. An exposure of the porous stratum where it may absorb water 

supplied either by direct precipitation or by percolation of waters 

falling on porous material above.

4. An inclination of the water-bearing stratum so that gravity 

may force the water down and produce an artesian head. This 

inclination may be due to the manner of original deposition, but is 

ordinarily caused by a displacement of the strata after deposition.

5. A lack of easy escape for the water at lower points than that 

where the porous material is penetrated, as the artesian head would 

be lost if the water had such escape.

6. A sufficient precipitation and absorption to keep the- porous 

material saturated and maintain the artesian head.

Although these conditions are partly realized at many places in 

Connecticut, they are generally modified by many factors. In the 

Connecticut Valley the relatively porous sandstone has a marked 

dip to the east, and it is not uncommon to find a stratum of sandstone 

confined between two layers of shale. However, these rocks are 

intersected by so large a number of fractures that the water which 

can not pass through the fine pores of the shale leaks through the 

jointed material, destroying the artesian head. At many places in 

Connecticut a number of springs occur in a relatively straight line, 

indicating the existence of a fracture plane along which Waters are 

escaping from confinement below. The artesian waters, instead of 

coming to the surface through artificial wells, are escaping through 

the openings furnished by nature. Fuller a has shown that artesian 

conditions may occur in such uniform materials as sand, owing to the 

overlapping of the elongated sand grains.

The fact that the ground water is in a state of continual motion, 

as shown by various experimental methods, implies that there must 

be some escape for the water at lower levels than that where it enters. 

Such natural escape may occur in a variety of ways. In a material 

of-uniform nature, as sand, the surfaces of streams, lakes, and swamps 

represent the level of ground water at that point and the escape is 

due to slow seepage. Bodies of water fed in such a way are'extremely

« Fuller, M. L., Water-Supply Paper U. S. Geol. Survey No. 145,1905, p. 41. 

463 IRR 232 09 4
50 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

variable, increasing and decreasing in amount as the water table 

rises and falls, owing to varying weather conditions. The way in 

which such streams are fed is indicated in figure 5.

SPRINGS.

A large amount of the escaping ground water emerges at the surface in the form of springs that are usually rather constant in the

FIGURE 8. Diagram illustrating manner in which spring may form at 

contact of soil covering and impervious rock below, when soil is removed by erosion, a, Point of emergence of the spring.

FIGURE 7. Diagram showing formation of a spring at the outcrop of an inclined impervious stratum.

S, Spring.

amount of flow throughout the year. Such springs may represent 

an escape of artesian waters through fissures, as stated on page 49.

Commonly they 

owe their existence 

to the presence of 

a stratum of pervious material overlying an impervious layer (fig. 7). 

The water penetrating the pervious layer is prevented from moving downward through the impervious layer, whose slope it follows until it finally emerges at the surface at the contact of the 

two layers.

Figure 8 represents a 

type of spring in which 

the top of a hill is capped

by a laver of Sandy Soil FlGUEE 9. Diagram illustrating manner of formation of spring

resting on impervious

rock. The ground water

follows the rock surface

until some opportunity is afforded for escape, when the water will

emerge as a spring.

at contact of pervious formation and impervious formation 

when dissected. A, C, Impervious shale beds; B, porous 

water-bearing sandstone; M, top of saturated zone; X, point 

of emergence of spring.
OCCURRENCE AND RECOVERY OF GROUND WATER. 51

Figure 9 represents the conditions where erosion has cut through the 

porous stratum and into the impervious layer, affording an easy escape 

for the ground waters. These diagrams represent two of the numerous 

ways in which springs may occur. Springs are usually seen issuing as 

streams rather than as a continuous seepage, both because the stream 

springs are more conspicuous and because if there is any considerable 

opening such as a joint crack the water will tend to concentrate in 

this open channel where the frictional resistance is least.

AMOUNT OF GROUND WATER.

It must be clearly understood that the amount of ground water 

is limited, as it depends on the amount of precipitation which is 

absorbed by the ground. The amount that escapes in the form of 

springs, though also dependent on the amount of precipitation,

FIGURE 10. Diagram illustrating effect of tides on' water table, a, Normal water table at high 

tide; b, normal water table at low tide; c, depressed water table during a dry season.

varies relatively less than the precipitation. The amount of precipitation, however, is variable, a dry season being marked by a 

lowering of the wlater table and a wet season causing a corresponding 

rise. The effect of these changes is always marked in shallow dug 

wells of the ordinary type, the water rising nearly to the top in 

winter and spring, whereas the same wells will be nearly or quite 

dry during the latter part of the summer. Springs also are affected 

to a certain extent by such seasonal changes, but the effect is relatively small as compared with wells. Variations in the level of the 

water table are also caused by barometric fluctuations, but though 

those variations may be sufficient to affect the amount of flow of
52 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

springs, as shown by F. H. King,0 they cause no permanent effect 

on the water supply. In wells near the coast fluctuations of the 

water table with the rise and fall of the tide are common, as the 

height of the sea water at high tide gives a slope to the water table 

differing from the slope at low tide. This.is shown in figure 10.

Neighboring wells will usually affect one another, as water can 

ordinarily be pumped from the wells faster than it can be supplied 

by the water-bearing material, and the water table is therefore 

depressed for a varying distance around the wells, so that heavy 

pumping of one well will cause the lowering of the water level in an 

adjacent well deriving its supply from the same source. It is not 

uncommon for an artesian well which had previously given a good 

flow to lose its flow entirely on the sinking of another well which 

happened to give an easier escape for the underground waters. As 

a rule the flow of artesian wells decreases with the lapse of time and 

the head gradually lowers, indicating that the well is exhausting the 

supply faster than it is renewed by precipitation, or, in other words, 

that the water table in the water-bearing material is undergoing 

continuous depression.

TEMPERATURE OF GROUND WATER.

When the water enters the ground it has a temperature corresponding to that of the atmosphere, but as it percolates downward 

it is affected by the temperature of the ground and within a very 

short distance from the surface acquires the temperature of the 

material through which it is passing. In any region there is a 

certain depth at which the temperature is constant throughout the 

year and is practically the same as the mean annual temperature of 

the region. In Connecticut this depth is 50 to 60 feet, and the mean 

annual air temperature is 47°, so that waters at about 50 feet below 

the surface will have this temperature. Most of the Connecticut 

well waters come from much shallower depths, and consequently 

have temperatures above or below this average, depending on the 

season of the year.

Below the level of constant temperature there is a fairly uniform 

increase of temperature with increase of depth, amounting to about 

1° F. for every 60 feet of depth. It is a common belief that the 

deeper the well the colder will be the water, but it will be readily 

seen that on this basis beyond a depth of 50 feet the deeper the 

well the warmer will be the water. This statement corresponds to 

the facts shown by the deep drilled wells of Connecticut, although 

in such waters there is a small change of temperature during the 

rise of the water to the surface.

a Movements of underground water: Nineteenth Ann. Kept. U. S. Geol. Survey, pt. 2,1899, pp. 75-77.
OCCURRENCE AND RECOVERY OP GROUND WATER. 53 

CONTAMINATION.

From what has been stated above, it is evident that ground water 

does not exist in pools or cavities in the rock and is not stationary. 

It has a movement in a definite direction, which can be determined 

for any given place. A velocity as high as 100 feet in twenty-four 

hours has been measured, but the common rates, even in sand, are 

only from 2 to 50 feet a day. (See p. 47.) The fact of the movement is undisputed and has an important bearing on health, for 

disease germs may be carried by water wherever it travels. No 

kind of rock or soil is proof against the transmission of ground water 

containing pollution. Fuller a has shown that water may traverse 

several miles of crystalline rock and may carry contamination 

through that distance. In a settled community too much emphasis 

can not be placed on the necessity of locating wells in positions 

where they are not liable to infection. The only safe way is to treat 

ground water as if it were a surface stream. No one would use 

water from a river a short distance below points of contamination, 

and no one should use water from wells where the downward slope 

of a ground-water table is such that the water might carry infected 

material. (See pp. 171-172.)

a Fuller, M. L., Bull. Geol. Soe. America, vol. 16,1905, p. 372.
CHAPTER IV.

GROUND WATER IN THE CRYSTALLINE ROCKS OF 

CONNECTICUT.

By E. E. ELLIS. 

INTRODUCTION.

The laws governing the occurrence of ground water in unconsolidated material and in porous sedimentary formations are now generally understood, but little has been written concerning the sources 

of supply for wells in the*so-called crystalline rocks. The term 

"crystalline rocks" is used for those rocks whose component grains 

have crystallized into their present relative positions, in contrast with 

the sedimentary rocks, which were laid down under water and generally consist of fragments of older rocks mechanically arranged. Under 

the head of crystalline rocks two main types may be distinguished 

(1) igneous rocks, such as granite, diabase, gabbro, etc., which were 

once in a molten condition and which crystallized and hardened on 

cooling; (2) metamorphic rocks, such as schists and gneisses, which 

were originally either sedimentary or igneous but have been altered 

by metamorphic processes to their present form.

Connecticut offers an exceptionally good field for an investigation of 

ground water in the crystalline rocks, as more than two-thirds of the 

State is underlain by rocks of this type (see fig. 11) and a large 

number of wells have been drilled in this area.

LITERATURE.

It seems necessary to dwell on the theoretical principles involved 

in the occurrence of ground water in crystalline rocks more largely 

in this paper than is customary in a report on underground water 

resources, because of the scarcity of previous information on these 

points. Accordingly a summary of the most important articles 

which have been written on such occurrences is here given. Many 

of these articles are contained in the discussions of the relation 

of circulating waters to ore deposits and to metamorphic changes. 

The principles involved, however, have been deduced for water circulation in general, both in rocks permeable because of their porosity 

and in rocks giving opportunity for circulation only through fracture 

planes; the latter type corresponds to the crystalline rocks under discussion. The theory as stated by Van Hise a considers that there

a Van Hise, C. R., A treatise on metamorphism: Mon. U. S. Geol. Survey, vol. 47,1904. 

54
GROUND WATEK IN CRYSTALLINE ROCKS. 55

are two general zones of water circulation a zone below the level of 

ground water, where all openings in the rocks are filled with water, 

and a zone above the level of ground water, where the openings are 

but partly filled. He considers the extreme possible depth of circulating waters to be about 10,000 meters, which is the limit at 

which open fractures may exist. The circulating waters are considered to enter the earth's crust at many points and as, owing to the 

force of gravity, they work downward, they tend to seek larger and 

larger channels, which offer less resistance to their flow, and finally 

to converge in some large channel and emerge at the surface at some 

point lower than that where they entered. Gravity is considered to 

be the primal force in producing this circulation. The chief objection to this theory has been the assumption of a saturated zone below 

a certain level. Similar theories have been less fully brought out by 

Daubree, and by De Lapparent.

Certain general statements regarding the occurrence of water in 

crystalline rocks and the procuring of water from joint planes are 

given by M. L. Fuller.a

In a paper on the water resources of a crystalline area in New 

Hampshire and Maine, George Otis vSmith 6 has discussed the manner 

of occurrence of water in these rocks. He considers that the movement of the water is confined to stratification partings, joint openings, 

and less continuous passages, the main circulation being along master 

joints which are nearly horizontal. The circulation is slow owing to 

the constricted nature of the openings, and the water supplying wells 

is contributed from distant areas and is confined largely to trunk 

channels. The occurrence of certain flowing wells'is attributed to 

constriction and cementation in the upper portions of the fractures, 

giving opportunity for hydrostatic pressure.

J. A. Holmes 0 describes the occurrence of water supplies from the 

contact of fresh rock and the decomposed portion above in the crystalline rocks of North Carolina, but considers the undecomposed 

rock to be an uncertain source of supply.

The only published discussion of well supply in the crystalline 

areas of Connecticut is by H. E. Gregory,^ who gives certain statistics regarding the wells in this area.

A number of records of wells drilled in crystalline rocks in New 

Jersey, Pennsylvania, New York, and Connecticut are given in the 

water reports of the New Jersey Geological Survey.

A. Daubree,6 in a treatise on subterranean waters, has paid particular attention to various types of fractures that offer passage to

a Occurrence of underground waters: Water-Supply Paper U. S. Geol. Survey No.114,1905, pp. 28-29,39.

6 Water resources of the Portsmouth-York region, New Hampshire and Maine: Water-Supply Paper 

U. S. Geol. Survey No. 145,1905, pp. 120-128.

c Notes on the underground supplies of potable waters in the south Atlantic Piedmont plateau: Trans. 

Am. Inst. Min. Eng., vol. 25, 1896, pp. 936-947.

<* Underground waters of Connecticut: Water-Supply Paper U. S. Geol. Survey No. 114,1904, pp. 78, 79.

« Les eaux souterraines, 1887, pp. 150-157, 271-277.
56 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

water. In considering rock fractures in relation to circulating 

waters he distinguishes three classes "leptoclases," or small discontinuous fractures such as occur in basaltic structure, dividing the 

rock into comparatively small fragments; "diaclases," characteristic of all rocks and dividing the rock into polyhedrons by their 

mutual intersections; and "paraclases," which represent such continuous fractures as faults. The diaclases or joints are considered 

as planes extending in many places more than 300 feet laterally, and 

a joint series may extend with the same mean orientation for many 

miles. Their vertical extent is variable. In discussing the occurrence of water in crystalline rocks Daubree notes the irregularity of 

occurrence and the general feebleness of springs from such rocks. 

He then states that however unimportant the movements of water 

may be near the surface, water-bearing fractures are still less accessible with depth, because they are less numerous and have tighter 

walls, and cites the experience of engineers in piercing the St. Gothard 

tunnel as proof. He also describes a series of three lava flows near 

Catania, which have absorbed an entire river into their fractures.

Nordenskiold ° has described a series of wells sunk at seven localities 

in Sweden on islands of igneous rocks such as granite, diorite, etc. 

These wells all obtained fresh water at a depth of 100 to 120 feet, and 

he considers the supply to be derived from horizontal fractures caused 

by the daily variations in temperature. He considers the most favorable localities to be where vertical joints are lacking, but does not 

account for the origin of the fresh water.

DISTRIBUTION AND CHARACTER OF THE CRYSTALLINE 

ROCKS IN CONNECTICUT.

The general distribution of the crystalline rocks in Connecticut is 

shown on the map (fig. 11), where the State is seen to be divided into 

three sections, consisting of two areas of crystalline rock separated 

by an area of sandstone and trap which occupies a general depression 

between the higher crystalline rocks. The crystalline areas are well 

drained, although here and there lakes of glacial origin occur, and the 

stream waters contain unusually small amounts of mineral matter. 

The softness of the water has been an important factor in determining 

the location of many of the great woolen mills throughout the State.

ROCK TYPES.

The three types of crystalline rocks that cover the greater part of 

Connecticut beyond the limits of the central Triassic area are granite, 

gneiss, and schist, although near the western portion of the State there 

is a considerable area of dolomitic limestone largely changed to mara Sur une nouvelle espece de puits dans les roches granitiques de la Suede: Compt. Rend. Acad. Sci., vol. 

120,1895, pp. 857-S59.
GROUND WATER IN CRYSTALLINE ROCKS. 57

ble. There are also several areas of more or less schistose quartzite. 

Cutting these formations are many masses of pegmatite and a few dikes 

of diabase or trap rock, and in the central Triassic area the trap occurs 

both as dikes and as surface flows standing in high hills and ridges 

above the general central plain.

Granite. There are many varieties of granite throughout the 

State, but they may all be distinguished by the characteristic granitic 

texture. The rock which throughout this discussion is considered 

as granite is in reality a granite gneiss that is, a granite which has 

been subjected to metamorphism and has thereby acquired a gneissoid 

structure. The original granite nature is clearly evident and as granFIGUEE 11. Map showing.areas of limestone, sandstone, and crystalline rock in Connecticut.

ite is a more popular name, this term is retained in the discussion, 

although on the map the designation granite gneiss is used.

The rock is composed mainly of grains of quartz, feldspar, and mica, 

which are of fairly uniform size and easily distinguishable from one 

another. The rock is massive and will split about as readily in one 

direction as in another, except in joint planes. Locally schistose and 

gneissose phases occur even in a typical granite, giving one direction 

of easy fracture in the plane of schistosity. The main granite area is 

in the southern portion of the State and extends along or near a large 

part of the shore line.

Along the coast from the New York state line to Bridgeport is an 

area of somewhat similar rock called granodiorite. This rock resem-
58 UNDEEGEOUND WATER RESOURCES OF CONNECTICUT.

bles granite but contains a much, larger proportion of the black mica 

(biotite). At many places in this area it is highly schistose and may 

be split much more readily in one plane than in others.

Gneiss. The gneiss is a more variable rock than the granite, presenting very different characteristics even in adjacent areas and lacking the uniformity of texture of the granite. It may be distinguished 

by its banded or streaked appearance. It contains a large amount of 

feldspar and usually a considerable proportion of black mica or black 

amphibole, which, being present in greater amounts along certain 

lines than along others, gives the rock an appearance of alternating 

darker and lighter streaks. In some of the rock these streaks are developed into even bands from one-half inch to 3 feet in width, which 

continue for several hundred feet with variations of less than an inch 

in thickness. The most conspicuous area of gneiss is in the southeastern and eastern part of the State. Another large area consisting 

mainly of schist injected by granitic material occurs in the vicinity of 

Waterbury.

Schist. Although schist usually contains a large amount of quartz 

and feldspar its most conspicuous constituent is mica, which on casual 

inspection appears to constitute the bulk of the rock. A careful examination will show that these mineral particles are much longer than 

they are wide and thick and that their longer axes lie in the same direction. This is the direction of schistosity or rock cleavage, and the rock 

splits along this plane much more readily than in any other direction. 

Wherever there is an exposure of schist the tendency of the rock to 

split along the plane of schistosity together with the high angles at 

which these planes usually stand gives a jagged and serrated appearance to the rock surface. The parting plane is usually rather uneven, 

but in certain types of schist it is very smooth and shows a shining 

surface in the sunlight. Schist of this type called phyllite, is too fine 

grained to distinguish the separate constituent particles and closely 

resembles slate, being in fact, intermediate between a slate and a schist. 

Certain of the chloritic schists of Connecticut assume a similar aspect. 

Though nearly all the Connecticut crystalline rocks are characterized 

by the presence of garnet, this mineral reaches its largest and best development' in the schists.

The greatest development of the schists is beyond the western 

border of the Triassic area and in the area running from Middletown 

to the northeast corner of the State.

Quartzite schist. There are several areas of an extremely quartzose 

schist in the northeastern and northwestern portions of the State. 

This rock is composed entirely of quartz grains and is supposed to 

represent a quartzite completely metamorphosed to a schist. In the 

western part of the State recementation appears to have taken place,
GKOUND WATER IN CKYSTALLINE KOCKS. 59

resulting in an extremely indurated rock more nearly resembling a 

true quartzite.

Pegmatite. Traversing many of these rocks are dikes and irregular 

masses of pegmatite, which are white or very light in color and 

consist in great part of large crystals of white or pink feldspar with 

quartz and in places bunches of broad-leaved mica. This rock is 

usually called "feldspar" by drillers and quarrymen.

Trap rock. The trap rock is familiar to nearly everyone, and is 

easily distinguished by its dark color and fine-grained and compact 

texture. It occurs in the crystallized rocks as intrusive masses or 

dikes of material which has been thrust into older rocks. The 

external appearance of these dikes in the highland areas is closely 

similar to that of the traps of the lowland, and in composition the 

two rocks are identical.

Limestone. The limestone is softer than any of the other rocks 

considered; it may be readily scratched by a knife and will usually 

effervesce when acid is applied. It is ordinarily white or gray in 

color, and is the only rock considered in the present discussion 

which may be definitely classed as of sedimentary origin without 

careful study. It is usually dolomitic that is, it contains a considerable proportion of magnesium carbonate and in many places has 

been metamorphosed to a genuine marble.

DRILLING PRODUCTS.

The marked characteristics of these rocks give equally characteristic products in drilling. In many places the drill will yield 

fragments that are large enough to show the general texture of the 

rocks. In others the drillings will all be in the form of rock dust. 

In general the granite drillings are even grained, with a large proportion of the white or pink minerals, quartz and feldspar, and the 

same character and color of material will be maintained for a number 

of feet. Gneiss gives a somewhat similar product but as a rule has 

a larger proportion of biotite (black mica) and the character of the 

drillings changes rapidly, usually every few inches. Schist is generally softer and more readily drilled than either granite or gneiss, and 

the drillings contain a conspicuous amount of mica which occurs in 

larger particles than the other minerals. As in granite, the drillings 

maintain a fairly uniform appearance. The phyllite is usually a 

hard rock to drill, owing to its fineness of grain and the nearly 

vertical position of its cleavage at many places. Trap rock is 

considered the most (lifncult rock to drill, because of its hardness; it 

is readily distinguished from the other types. Limestone drillings 

are ordinarily whitej and may be tested by adding acid or strong 

vinegar, which will produce an effervescence, owing to the escape of 

carbon dioxide.
60 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

DRIFT.

Although in some places, particularly in the southern- part of the 

State, the rocks above described are exposed at the surface, they are 

in large part covered with glacial deposits till and stratified drift. 

The till occurs as a relatively thin layer over the rock surface both 

in valleys and on hills, and the valleys are filled with heavy deposits 

of stratified sand, gravel, and clay deposits resting upon the till and 

tending to form a flat valley floor. At many places the till has been 

eroded and the stratified deposits rest directly on the rock. The 

till deposits on the hills average about 15 feet in thickness, varying 

where present up to 60 feet or more; the valley deposits at many 

places are over 100 feet thick and average about 36 feet, although 

varying within very short distances owing to the irregularities of the 

underlying rock surface. These averages are made from the well 

records in the crystalline areas.

In general, therefore, the hills have a configuration corresponding 

rather closely to that of the underlying rock surface, the minor 

irregularities of which are masked by the overlying drift. On the 

other hand, the valley bottoms are flat and a decidedly different 

topography would be shown if the sand and gravel deposits were 

removed. The general relation of the glacial deposits to the underlying rock and to each other are indicated in figure 23.

CONDITIONS AFFECTING OCCURRENCE OF WATER IN 

CRYSTALLINE ROCKS.

INTRODUCTION.

The occurrence of water in crystalline rocks is necessarily unlike 

that in most kinds of water-bearing sedimentary rocks, owing to the 

great difference of texture in the two types. In unmetamorphosed 

sedimentary rocks the pore space is usually large, running above 

20 per cent of the total volume in many sandstones and locally 

above 40 per cent. This means that such rocks will absorb an 

amount of water equal to one-fifth or even two-fifths of their entire 

volume. In the crystalline rocks there is little pore space between 

the constituent grains, which have crystallized into their present 

relative positions and therefore closely interlock with one another. 

Few of the granites have a porosity exceeding 1 per cent, and the 

average is 0.5 per cent or lower.0 In gneissoid granites the proportion of pore space is about the same, and in slates it is less, averaging 

0.45 per cent or lower. Although in many limestones the porosity 

runs above 10 per cent, their metamorphosed equivalents the 

marbles have a porosity about equal to that of granite.

oBuckley, E. R., Building and ornamental stones of Wisconsin: Bull. Wisconsin Geol.Survey No. 4, 

1898, p. 374.
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 232 PLATE I

A. VERTICAL JOINTS IN GRANITE.

B. HORIZONTAL JOINTS IN GRANITE.
GROUND WATER IN CRYSTALLINE ROCKS. 61

In such rocks as these, which absorb less than 0.5 per cent of their 

volume of water and contain less than 1 per cent of uniformly 

distributed pore space, the pores are mainly of subcapillary size and, 

though admitting water, allow little and exceedingly slow transmission. In many of the sedimentary rocks, on the other hand, the 

openings between the grains are of capillary or supercapillary size 

and give ready transmission to circulating waters. Therefore in 

the crystalline rocks the only circulation of water which has 

sufficient rapidity of movement to be of value as a source of well 

supply must be through joints and fractures developed subsequent 

to the crystallization. (See fig. 12.)

JOINTS.

A joint in rocks may be defined as an opening or fracture of great 

length and depth as compared with its width. Joints are produced 

by mechanical action 

which causes the rock to 

break into more or less 

regular blocks after it 

has hardened. They 

are usually attributed 

to some dynamic force 

that brings about movements in the earth's 

crust. They are ordinarily called seams or 

cracks by drillers.

Vertical joints. The 

most common type of 

joints comprises those 

in planes approximating a vertical position.

(See PL I, A.) Though FIGURE 12. Diagram illustrating the manner in which a well 

there are many joints obtains water by cutting joints.

within 2 ° or 3 ° of verticality, the greater number deviate considerably from this position. A large number of measurements were made 

on the inclination of this type of joint in the crystalline areas of 

Connecticut, the average inclination of a series at any exposure being 

taken rather than a number of measurements on separate joints at 

the same exposure. The mean inclination, as shown by 75 observations, was 74° from the horizontal. In only four observations did 

the inclination run below 40°, in 14 it was between 40° and 70°, in 

17 between 70° and 80°, and in 40 between 80° and 90°. It is evident that in the Connecticut crystalline rocks the main jointing is 

between 70° and 90°. In several of the places where lower inclinations were observed the jointing was parallel to some structure plane 

in the rock,
62 UNDEEGEOUND WATEE EESOUECES OF CONNECTICUT.

Horizontal joints. In many of the rocks there is another set of 

joints which are very distinct from those of the vertical type, both 

in their degree of inclination and in their general nature. This set 

occupies an approximately horizontal position, in few places pitching 

more than 20°, and as a rule much less than this. (See PI. I, B.} In 

general this joint structure follows the surface configuration of the 

rock, but here and there it pitches at a low angle in an opposite direction to the slope of the hillside. In the most extreme cases of deviation from a horizontal position this jointing was found to be approximately parallel to planes of schistosity in the rock. This is well 

shown in the lower of the two gneissoid granite quarries near Maromas.

In the further discussion of jointing, the names vertical jointing and 

horizontal jointing will be used for these two main types.

Relation of rock type to jointing. Both vertical and horizontal 

jointing are present in all the crystalline rocks, but occur in greatly 

varying degrees of development in the differing types. The horizontal joints are typically developed in the massive granites, where 

they are commonly very regular. They form the most striking 

feature of quarries in such rocks and constitute the plane of separation called ' 'bedding" by the quarry men. In the gneissoid granites 

these joints are developed equally well, but their direction is determined by the gneissoid structure in some places where that lies at a 

low angle to the horizontal.

In the typical gneisses the joints are irregular and uncertain and 

occur only near tho surface; in the schists they are usually lacking, 

although here and there irregular and discontinuous fractures may 

be seen running in a nearly horizontal plane. Where such horizontal 

fractures occur in schists they are usually near the surface and very 

open.

The vertical jointing is not confined to any particular rock type, 

but is developed throughout all consolidated formations, both sedimentary and igneous. The degree and nature of the development, 

however, vary not only with varying rock types, but also to a great 

extent in rocks of the same type in different localities. This difference of development at the contact of rocks of two distinct types may 

consist of a mere tightening or closing of the joint on passing into the 

second rock, or of a difference in the number of the joints in the two 

rocks, indicating that some joints have stopped at the contact lines. 

Numerous instances of the former difference have been noted in the 

studies of ore bodies, and a good example on a small scale, typifying 

both differences, may be seen in the railroad cut just west of the 

station at West Haven, Conn. Here lenses and streaks of extremely 

schistose and slaty rock occur with 'similar layers of compact diabase 

several feet in thickness. The diabase is completely traversed by
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 232 PLATE

A. JOINTS IN SCHIST AND METAMORPHOSED DIABASE

B. JOINTED AND FISSILE SCHIST.
GROUND WATEE IN CRYSTALLINE ROCKS. 63

joints and seams, some of which stop abruptly at the contact with 

the schistose rock, while those which continue across the schist are 

relatively tight. A similar occurrence on a larger scale may be seen 

on the north bank of Housatonic River, 3 miles above Derby, where a 

schist lies above a heavy pegmatite. It is impossible with present 

evidence to say what will be the rule in this respect at the contact 

of a schist and a granitoid rock, but it seems probable that in most 

such places the joints will become tighter and less numerous in passing 

from a granitoid to a schistose rock. (See PL II, A, B.)

Joint direction. Any individual joint maintains a fairly constant 

direction with a few small curves, and here and there the same directions of prominent jointing will remain fairly constant over a considerable area, as shown by the observations of Hobbs a in the Pomperaug Valley, where he found four major directions of jointing. Where 

there is a particularly well-developed joint set the series may maintain 

the same general direction for long distances.

In a series of observations throughout the crystalline areas of the 

State it was found by the writer that a much larger proportion of 

joint systems ran in a northwest-southeast direction than in one 

northeast and southwest. However, for particular localities the direction of jointing can be determined only by local observations.

Structure planes. Of secondary importance to the joints as regards 

water supply is the presence of structure planes, such as schistosity 

and gneissoid banding in the rocks. In rocks exhibiting these 

features there has been more or less fracturing parallel to the structure 

planes, which have-an average inclination much lower than the joints. 

The planes of schistosity dip at all angles, but for any single formation 

there is usually some dip which is more constant than others. Observations on these formational dips in Connecticut show them to be 

quite as commonly below 45 ° from the horizontal as above that angle, 

whereas, as previously shown, most of the joints, exclusive of the 

horizontal joints, have greater dips than 75°.

The fracturing parallel to the schistosity may consist of rather 

widely spaced and relatively open fractures or of small discontinuous 

breaks an inch or less apart, producing a structure known as fissility. 

Whatever the nature of these fractures, they will average a lower 

inclination than joints, although in some rocks, as in the chlorite 

schist and phyllite west of New Haven, they are nearly vertical.

Variation in jointing. In the schists and similar rocks, with a 

marked schistose structure, such as the schistose granodiorite along 

the coast east of Greenwich, there is usually one direction or system 

of jointing that is more prominent than any other. This main system

a Hobbs, W. H., The Newark system of the Pomperaug Valley, Connecticut: Twenty-first Ann. Kept. 

U. S. Geol. Survey, pt. 3,1901, pp. 7-162,
64 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

is, as a rule, accompanied by a wider spaced and less well developed 

series of joints intersecting the main series at high angles. In the 

schistose granodiorite the jointing is well developed, rather closely 

spaced, and very uniform in direction. In the schists the joints 

maintain a fairly uniform trend, but are commonly very tight, and 

in much of the rock die out within short distances. In most exposures one or two distinct series of joints can be distinguished, and 

many small irregular fractures connecting the main joints occur near 

the surface, but disappear at relatively shallow depths.

In the granitoid rocks the vertical joints are generally more open 

and continuous than those in the schistose rocks, but usually lack 

their characteristic regularity of arrangement in series and are ordinarily more widely spaced. Although in many of these rocks there 

is one set of joints with a general parallel direction, even in the joints 

which may be classed in the same series there may be a variation of 

10° to 20° in direction, and other vertical joints may intersect these 

with no regularity of arrangement with reference to each other. 

This is the usual occurrence of jointing in the Connecticut crystalline 

rocks of this class, but in certain places two, three, or even four distinct sets of joints may be distinguished.

The limestones of the State are even more irregularly fractured 

than the granites and the fracturing is usually so close as to prevent 

the use of the rock as building stone. Joints cut these rocks at all 

angles, and the general shattering has produced more open space 

than in any other type of rock which might be classed as crystalline.

No general conclusions on the occurrence of vertical joints in the 

crystalline areas of Connecticut will hold for every portion, as there 

is great variation in their occurrence within short distances, even in 

the same formation. On the other hand, the horizontal joints have 

a very uniform mode of occurrence for all the granitoid rocks. They 

are approximately parallel to the rock surface, except where influenced by local factors such as structure planes, and are spaced at 

fairly uniform distances from one another. They are everywhere 

curved or wavy and intersect one another at varying intervals, 

dividing the rocks into a series of approximately horizontal wedges 

with curved faces. The principal variation is in the closeness of 

these intersections. In some places the horizontal joints intersect 

one another every 20 or 30 feet; in others they run parallel to one 

another for 100 feet or more. In general the horizontal jointing is 

more regular, though not necessarily better developed, where the 

amount of vertical jointing is small. A good example of this may be 

seen in the gneissoid granite quarry at Monson, Mass., where there is 

an excellent parallel horizontal jointing but vertical joints are almost 

lacking and except at the immediate surface are filled with vein 

material.
GROUND WATER IN CRYSTALLINE ROCKS. 65 

FAULTS.

Faults may be considered as extreme types of joints in which there 

has been movement of one wall of the joint plane past the other. 

The work of Hobbs, Davis, and others has shown that there has been 

a considerable amount of faulting in Connecticut, and it is not uncommon to find strongly marked shear zones, indicating slipping in 

the crystalline rocks. These are rather rare phenomena, however, 

and are seldom encountered in well drilling; accordingly they will be 

treated simply as special cases of jointing. They are probably very 

important as channels for spring waters, although it is extremely. 

difficult and generally impossible to ascribe any particular spring to

a fault plane.

«

CIRCULATION AND STORAGE OF WATER.

The circulation of water in the crystalline rocks, being confined to 

openings of the sort discussed in the foregoing pages that is, those 

having great length as compared with their thickness is necessarily 

limited by the abundance of these planes of parting, by their degree 

of opening, and by their intersection of one another; and there are 

many modifying factors, such as local entrance conditions for surface 

waters, local textural variations in the rock, intrusions and inclusions 

of other rocks, and the restraining effect of overlying glacial drift.

INFLUENCE OF JOINTS AND OTHER OPENINGS.

Spacing of vertical joints. The vertical joints, which are the important water carriers, have no regularity of spacing even in the 

same rock. These joints are much more closely spaced in natural 

outcrops, owing to the influence of weathering, and in railroad cuts 

where there has been heavy blasting than in quarries where the natural 

conditions prevailing in the rock below the surface are exhibited. In 

such natural exposures the spacing of joints was found to vary from 

a fraction of an inch up to 200 feet or more. The extremely close 

jointing occurs only in sheeted or shear zones which vary from a few 

inches to 2 feet in width, and these sheeted zones-are a considerable 

distance from one another. Instances of such close sheeting as to 

give a spacing of 1 inch are exceptional, and are found in relatively 

few exposures. The same general occurrence on a larger scale, however, is typical of vertical jointing. In every quarry observed in 

Connecticut where jointing is developed over a considerable area the 

joints were found to be much more closely spaced at certain points 

than at others, constituting a series of zones of close jointing separated 

by intervals in which the distances between joints are much greater. 

These zones of close jointing vary from 1 foot to 15 feet in width and 

the joints making up the sheeted areas are spaced from 3 inches to 

463 IRR 232 09 5
66 TJNDEKGKOUND WATBK EESOTJECES OF CONNECTICUT.

2 feet apart. Purington a describes a similar but more regular occurrence in a Colorado mine where, along the side of a drift, fissures 30 

feet apart become nearer and nearer together until they are only

3 or 4 inches apart, forming a sheeted zone, beyond which the intervals 

gradually increase.

A number of observations on joint series in the Connecticut crystalline rocks indicate that at the places where jointing is well developed 

the average spacing is between 3 and 7 feet. It is very difficult to 

form an estimate of the average spacing for all rocks, however, for 

in some localities, as in the quarries at Monson, Mass., and Sterling, 

Conn., there are exposures of several acres where the rock has been 

quarried, and not more than three or four open joints can be distinguished in the entire quarry, giving a spacing of at least 100 feet. 

Here and there older joints may be distinguished which have been 

filled with vein material, but these can yield no water under present 

conditions.

If it were supposed that all the vertical joints were placed in parallel 

planes, both major and minor series, it is probable that the average 

spacing would not be less than 7 feet to a depth of 50 feet from the 

surface. The average spacing between vertical joints of the same 

series for the crystalline rocks, exclusive of trap and limestone, is 

more than 10 feet for this same zone of 50 feet from the surface, as 

shown by field observations, and the study of well records indicates 

that this is not far from the average spacing for all joints to a depth 

of 100 feet.

Spacing of horizontal joints. The horizontal joints present much 

greater regularity of spacing than the vertical joints. They are 

apparently surface phenomena and diminish in number rapidly with 

increasing depth; it is probable that they do not exist at a depth of 

200 feet. For the first 20 feet below the surface these horizontal 

joints average 1 foot apart, for the next 30 feet they average between 

4 and 7 feet, and for the next 50 feet they are much more widely 

spaced, being from 6 to 30 feet or more apart.

Continuity of horizontal joints. The length of individual horizontal joints rarely exceeds 150 feet, but owing to their intersection 

of one another they may constitute a continuous opening several 

hundred feet long, which would have the form of a curved sheet 

approximately parallel to the hill slope, each lower sheet having less 

curvature than the one above. They are probably better developed 

on the hills than in the valleys, as the pitch of the joints is usually 

less than the slope of the surface, which consequently cuts across 

the joints. Moreover, as they are more widely spaced with depth 

the horizontal joints that cross the valleys are widely spaced.

a Purington, C. W., Preliminary report on the mining industries of the Telluride quadrangle, Colorado: 

Eighteenth Ann. Kept. U. S. Geol. Survey, pt. 3, 1898, pp. 765-769.
GEOUND WATEK IN CKYSTALLINE KOCKS. 67

Continuity of vertical joints. There are two directions in which 

vertical joints may have great length vertically, or along their dip, 

and in the direction in which they cut the surface. No mathematical 

relation between these two directions has been determined, but it 

has been assumed in the study of ore deposits that a fracture will 

have about as great extent along the dip plane as along the strike 

plane.0 The degree of continuity is very uncertain owing to the 

difficulty of direct observation on either the entire length or the 

depth of any joint, and to the fact that a joint may exist with its 

two sides so closely pressed together that the fracture is not apparent 

to the naked eye. It is certain that some joints are far more continuous than others and that many die out within very short distances 

both vertically and laterally. Faults have the greatest continuity 

and may extend for several miles across the country, or even for 

tens of miles. The sheeted zones of closed jointing are probably 

almost as continuous as faults, and their dimensions should be 

measured in hundreds of feet. Where there is a well-defined series 

of parallel joints the prominent joints may extend for several hundred 

feet, while the minor intersecting joints will be much shorter.

Fissility and schistosity openings. The circulation of water as 

determined by structure planes has not been discussed up to this 

point because the evidence is not as clear as in the case of joints. 

Although it is probable that the absorptive capacity of a schist 

would be greater than that of a slate, owing to the larger size of the 

grains, the porosity would still be too small to allow any circulation 

in the pores. In a crumpled schist there are probably small openings between the folded laminae, but these must be discontinuous 

and would not allow sufficiently rapid circulation for well supply. 

However, there are nearly everywhere fractures of considerable 

extent parallel to the schistosity, but with much less regularity of 

occurrence than the joint planes in the same rock. These fractures 

also are much less continuous than joints and die out within short 

distances.

In such discontinuous fractures the circulation would be comparatively slow, but sufficient for well supply. Small springs issue 

from such fractures at many places, as along the east bank of 

Connecticut River above Hadlyme Landing. These fractures are 

much more numerous near the surface, particularly where the dip 

of the schistosity is in a low plane, and become tighter and less 

abundant with increasing depth.

Intersection of fractures. It has been shown that the main circulation of water available for well supplies in crystalline rocks is along 

jointing planes, and it will be shown later that some joints carry a

a Ransome, F. L., Economic geology of the Silverton quadrangle, Colorado: Bull. U. S. Geol. Survey No. 

182,1901, pp. 61, 62.
68 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

greater amount of circulating water than others. It is evident that 

the * intersection of joints with one another is a very important 

factor in determining the degree and direction of the undergroundwater circulation.

The manner of occurrence of joints indicates that such intersection 

may be found in every possible direction, but that there will be 

much better connection in some of them than in others. In the 

granitoid rocks, where the vertical joints have little regularity of 

arrangement and therefore intersect one another at many points, 

and where the horizontal joints are nearly universal, there is a 

thorough connection between the various fractures of the upper 

zone in which the horizontal joints occur. In the schists and schistose gneisses, in which the joints are usually more regular in arrangement and in which the horizontal joints are poorly developed, the 

connection between the various joints is less complete. In these 

schistose types, as in the granitoid rocks, there are invariably cross 

joints connecting the main systems, but they are commonly considerable distances apart and are tighter than the main joints, so 

that the opportunity for lateral transmission of water from one 

joint to another parallel joint is less than for longitudinal transmission along the main joints. The connection of the small and 

discontinuous fractures in the planes of schistosity is much poorer 

than that of the joints.

Opening of joints. The degree of opening between the walls of 

joints is exceedingly variable and very difficult to measure. At the 

immediate surface many joints have an opening of half an inch to 2 

inches, or even much greater. This wide opening is due to various 

weathering and mechanical agencies, which act only near the surface, 

and consequently is not found at depths below which these agents act. 

In an artificial cut, such as a quarry wall, many of the joints which 

may be open half an inch at the surface are too tight to admit a 

knife blade at a depth of 25 feet.

The joints at 30 feet below the surface may have only one-twentieth 

the opening that they have at the surface, but the same proportionate 

tightening will not continue at lower depths, although it is certain 

that the greater the depth the greater must be the tendency of joints 

to close, owing to increased pressure and to the smaller opportunity 

for lateral expansion below the level of minor topographic relief.

The closing with increasing depth is, of course, a measure of the 

vertical continuity of the joint, and it seems very probable that there 

is a direct relation between vertical and longitudinal continuity. 

Accordingly there is .a great variation in the depths at which different 

joints close; the smaller joints close at moderate depths, but the 

larger joints continue to varying greater depths according to their 

importance.
GROUND WATER IN CRYSTALLINE ROCKS. 69

If the above statement holds true, the closing of the joints produces 

not only a tightening with increasing depth, but also a decrease in 

number or a widening of the space between joints. This principle 

applied to the vertical joints is closely analogous to the tightening 

and increase of spacing of the horizontal joints with increasing depth, 

which may be observed at nearly any granite quarry, although the 

causes producing the two types may be different.

The application of this principle in the drilling of wells is of the 

utmost importance, as it is frequently asserted that water can always 

be obtained by going deep enough, whereas the deeper the well the 

less the chance of striking fractures, which are the only passages 

permitting water transmission in crystalline rocks. It is evident 

that,, owing to the closing with depth, there will be a much greater 

circulation in the upper half than in the lower half of any individual 

joint.

Though many of the joint openings are supercapillary in size, 

most of them are probably of large capillary size. The upper limit 

of capillary sheet openings is about one one-hundredth of an inch, 

which gives an opening of appreciable size, but in a freshly quarried 

wall the greater proportion of the joints have manifestly less width 

than this. A rough estimate of the degree of opening .of joints may 

be made from the yield of wells in the crystalline rocks, which average 

about 17 gallons a minute, although the greater number give less 

than 15 gallons a minute. The average well intersects between three 

and four joints, and this number of saturated joints would supply 

much more than the average yield of the wells if the openings were 

appreciably larger than capillary size. These openings, however, 

must be toward the upper limit of capillarity in order to yield 10 to 15 

gallons a minute. Some wells undoubtedly pass through openings of 

much greater width than 0.01 inch, and nearly every well driller can 

cite several instances when his drilling tools have suddenly dropped 

several inches. Although the driller usually considers the sudden 

fall of the tools to indicate an open crevice, the probability is that 

no actual open space exists, but that a fracture has been encountered 

in which decomposition has softened the rock walls to such an extent 

that the material offers little' or no resistance to the heavy drill. 

Nearly every quarry in the crystalline areas of Connecticut gives 

examples of such decomposed strips bordering joints, but such an 

occurrence as an opening wider than a fraction of an inch in crystalline rocks, except at the immediate surface, is practically unknown 

to quarrymen.

It is probable that openings of considerable size occur along fault 

planes, but faults are relatively few as compared with joints, and 

there is small chance of a drill hole penetrating them. Some of the 

wells of larger capacity may derive their water from such fault
70 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

openings, although more probably it comes from a closely sheeted 

zone.

Number of contributory joints. The number of fractures supplying 

water to a single well varies greatly in different wells. In some 

wells the greater part of the water appears to come from a single 

opening; in others the water comes in slowly from a large number 

of openings. In the average well there are from one to four horizons 

at which the principal supplies of water are obtained, although the 

yield from one of them is usually greater than that from all the others 

together. This is particularly true of the wells from 200 to 300 feet 

deep, in which the principal source is usually very close to the bottom 

of the well.

From the character of the fractures in the varying rocks it seems 

probable that the wells in gneiss and the deeper wells in granite 

derive their main supplies from one or two comparatively large openings, but that in the more schistose rocks the fractures contributing 

water are more numerous but less open. In the upper portions of 

the wells in granite the horizontal joints contribute a" series of small 

supplies below the point where the water level is struck.

If an average inclination of 70° from the horizontal and an average 

spacing of 10 feet is assumed for the vertical joints for the upper 200 

feet of rock, each well 200 feet in depth would intersect seven joints. 

This is probably not far from the average for all the wells, exclusive 

of the small and discontinuous fractures near the surface. Below 200 

feet the average number of joints intersected would be somewhat 

decreased for the next 100 feet and greatly decreased at lower depths 

than 300 feet. It is evident that in some localities the joints are 

much more closely spaced than in others, that locally they are highly 

inclined and elsewhere lie at low angles, and that all these factors 

modify the number of fractures which a well intersects.

WATER LEVEL.

If the fractures were all equally open and had complete connection 

with one another, there would be a zone of saturation in the crystalline rocks and the upper surface or water table of this saturated zone 

would follow rather closely the shape of the rock surface, as in sand 

or other homogeneous porous material. Under such conditions the 

water in adjacent wells should rise to the same level. In homogeneous sands the upper limit of the saturated zone is called the water 

table. In describing the occurrence of water in joints the term 

"water level" will be used to indicate the upper limit of the saturated portions of the joints.

Observation shows that the fractures are of greatly varying degree 

of opening, and that although most of them are connected with one 

another in some way the connection is much better in some places
GROUND WATER IN CRYSTALLINE ROCKS. 71

than in others. It is to be expected that under such conditions water 

will rise to different heights, even in joints which are close together, 

when there is no connection or very poor connection between them. 

As a typical instance of such variation may be cited the wells drilled 

for the Fitch Home for Soldiers at Noroton Heights, Conn. One well 

was drilled to a depth of 425 feet in the bottom of a small valley, 

resulting in a flow of 4 gallons a minute that rose more than 7 feet 

above the surface. A second well was drilled 130 feet away and at 

an elevation only 4 feet higher, to a depth of 503 feet, and in this 

well the water rose only within 15 feet of the surface. Both wells 

passed through about 12 feet of hardpan. The difference of pressure 

head in these wells, only 130 feet apart but evidently deriving their 

water from different fractures, is therefore more than 18 feet. Both 

these wells give heavy yields on pumping and the pumping of the 

second well does not affect the flowing well, although it lowers the 

level of the water in an old drilled well higher on the hillside. Similar 

occurrences have been noted at other places, even in wells less than 

100 feet deep.

FIGURE 13. Sketch showing relation of water level to topography, a, Surface of ground; 6, line indicating height at which water stands in wells; c, rock surface.

Although there are local irregularities in the water level in the 

crystalline rocks, such as that just described, the general surface of 

the saturated zone still follows the topography, as is shown by the 

heights at which the water stands in the various wells. (See fig. 13.) 

The following table indicates the relation of the level at which the 

water stands in the wells to the surface of the rock:

Relation of water level in wells to surface of rock.

Position.

Hills ...................................................

Number 

of wells 

averaged.

42 

24 

35

Percentage with water level 

Below 

rock 

surface.

61.9 

12.5 

48.5

Above 

rock 

surface.

26.2 

87.5 

40.0

Even 

with rock 

surface.

11.9 

0 

11.5
72 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

It is thus evident that on the hills the water tends to stand below 

the rock surface, but that in the valleys it is under sufficient hydrostatic head to rise above the rock surface and under favorable conditions to cause flowing wells.

At' many places on the hills the tendency of the water level in 

the crystalline rocks to stand lower than the rock surface gives 

rise to an unsaturated zone immediately below the drift, although 

the lower portion of the drift itself may be completely saturated 

and furnish excellent supplies for comparatively shallow dug wells 

of'large diameter. The existence of such an unsaturated belt is 

believed to be due to the facts that the movement of water in certain 

places is more rapid through the upper fractured portion of the 

rock where the joints are open than through the relatively small 

capillary openings of the drift and that the water, having opportunity 

to escape from the rock crevices at some point lower than the entering point, is carried away down to a certain level faster than it is 

furnished. In some localities, however, where the fractures do not 

allow escape at lower levels, the water table of the drift and of the 

rock may be the same; that is, in wells deriving water from rock 

seams the water may rise to the same level as in open wells in the 

drift aboVe. However, owing to the generally rapid movement in 

fracture planes the general water level tends to approach a flatter 

plane in crystalline rocks than in porous materials like sand, where 

there is greater frictional resistance to water flow and where the 

effect of capillary flow is greater.

'The term "water level," as used in reference to the depth below the 

surface at which water stands in the openings of crystalline rocks, 

in its broad sense, implies a surface with much smaller differences 

of elevation than the water table of a sandstone area having similar 

topographic relief, but with much greater minor irregularity, owing 

to the great variation in the water channels. The larger fractures 

extending for long distances usually have some outlet to the surface, 

but in many of the smaller joints the water passes from one joint to 

another with no surface outlet. The fast flow in the larger joints 

lowers the level of the water in these and connected joints below 

that in neighboring unconnected joints having poorer outlets. Even 

in a connected series the water level will have different heights in 

joints of varying opening, owing to the faster flow in the more open 

joints, where friction is less.

DIRECTION OF CIRCULATION.

The movement of water entering any joint above the point where 

it is saturated with water will be mainly vertical along the dip or 

inclinatio'n of the joint. The circulation below the water level in 

any joint is both vertical and lateral. The lateral motion, along the
GROUND WATER IN CRYSTALLINE ROCKS. 73

strike of the joint, predominates, owing to the fact that the length of 

the outlet or outlets for any particular joint is much smaller than the 

total length of the joint. Any connected series of joints there will 

manifestly have a very complex circulation, but the main circulation 

will be toward and along the fractures having the largest openings and 

the nearest outlets, and in these fractures the general movement will 

be in the direction in which the land slopes.

DECOMPOSITION AS A MEASURE OF CIRCULATION.

The relative importance of various joints in the water circulation 

is indicated by the decomposing effect of the water on the walls of the 

fracture planes. The oxidizing surface waters carrying carbon 

dioxide and organic acids naturally react on the minerals in the rock 

walls, the action being indicated in some places by a mere reddishbrown staining of the joint sides and here and there by a breaking 

down of the mineral particles, giving rise to a disintegrated border 

along the joint plane. There is a great difference in the amount of 

this weathering, even in joints which may be adjacent members of 

the same series, indicating that some joints are heavier water carriers 

than others of the same age, probably owing to greater opening and 

in some of them to better entrance conditions. The areas of greatest 

decomposition are along the sheeted zones, and next along the most 

continuous vertical joints, and in these fractures the weathering 

extends down to the limit of observation, with no apparent change. 

In the minor joints the weathering effects are less conspicuous and 

usually appear to the observer as mere discolorations, extending from 

half an inch to 3 inches or more on each side of the joint plane and 

becoming less marked with increasing depth.

As a rule the horizontal joints of the granitoid rocks show less 

weathering than the minor vertical joints. Though usually discolored 

and weathered near the surface, the walls of these joints are commonly 

unaltered at a depth of 20 feet. However, where the horizontal 

joints are cut by a prominent weathered vertical joint, the weathering 

effect extends along the adjacent horizontal joints to a very marked 

degree, diminishing in amount with increasing distance from the vertical joint. This feature is well shown in the granite gneiss quarry of 

the Rhode Island Brown Stone Company, 1J miles west of the railway 

station at Oneco, Conn. At this quarry a heavy discoloration extends 

along the flat joints for a distance of 25 feet from a vertical joint, 

gradually diminishing in intensity. Occasionally a flat joint is found 

which is weathered throughout its exposed length. (See PL III, B.)

In the sheeted zones it is common to find a strip of disintegrated 

material from 1 to 6 inches in thickness and in the large single vertical joints similar but narrower bands of disintegrated rock occur.
74 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

Through such material as this a large amount of water can pass with 

comparative ease.

If the degree of decomposition along joint planes is taken as a criterion of the amount of circulation along the joints it would appear 

that the circulation is mainly along the large vertical joints, next along 

the minor vertical joints, and in small amounts along the horizontal 

joints. Although this statement is probably true as to the proper-, 

tionate amounts of circulation it does not mean that the unweathered 

vertical or horizontal joints are dry. The probability is that the 

lower horizontal joints are saturated with water, but that owing to 

the relatively flat planes in which they lie and their tendency to 

tighten at their intersection with one another, the water has a very 

feeble circulation.

The horizontal joints are probably much younger than the vertical 

joints and weathering has had less time in which to act, but the fact 

that some are weathered more than others indicates that even in these 

joints, which are manifestly of the same age, some offer better conditions than others for water circulation.

STORAGE OF WATER.

The wells in the crystalline area of Connecticut are remarkably 

constant, showing little variation in yield or depth of water, either 

annually or through a period of years. In some the yield has 

increased since the well was drilled and in a few it has decreased, but 

most of the wells have shown no appreciable change. The level to 

which the water rises in the wells shows nearly as great constancy 

as the yield, although in the shallower wells the water level varies 

somewhat with seasonal variations in rainfall, and in some of the 

deeper wells a lowering of water level has been noticed in unusually 

dry years. These fluctuations are most conspicuous in wells of 

small yield. In nearly all wells the water level is lowered to a greater 

or less extent on pumping, until by this lowering a sufficient increase 

of head is obtained to give an increased rapidity of flow, which will 

furnish a yield equal to that pumped out. When the pump is stopped 

the water will gradually, or in some wells very rapidly, rise again to 

its normal level. Minor fluctuations are probably more common 

than is reported, as changes in level are not readily noticed in covered 

wells. However, it is evident that there must be a very constant 

supply of underground water to maintain so constant a level in the 

wells.

The total average yearly rainfall in Connecticut is 46.89 inches, 

rather uniformly distributed throughout the year, and this uniformity of precipitation will, under natural conditions, with no 

artificial removal of water, give a fairly constant level for ground 

water in the rocks. If 25 per cent of this amount of rainfall is
GROUND WATER IN CRYSTALLINE ROCKS. 75

assumed to be absorbed by the rocks undoubtedly a considerably 

higher percentage than is actually absorbed the total amount 

absorbed by an area of rock 100 feet square is 9,768 cubic feet, or 

73,260 gallons. A well pumping 15 gallons a minute, which is about 

the average yield of wells in the Connecticut crystalline rocks, would 

draw out this amount in 81.4 hours. A well of this capacity pumping 

for 300 days during the year for one hour a day would withdraw an 

amount of water equal to 25 per cent of all the water falling on an 

area within a radius of 108 feet around the well. Probably 10 per 

cent of the precipitation more nearly represents the proportion 

absorbed by the rock than 25 per cent, and if so a well pumping at 

the rate above indicated would draw all the water on an area more 

than twice as great. When it is considered that some wells are 

pumped at the rate of 30 gallons a minute for ten hours a day throughout the year, it is evident that a single well may drain a very large 

area of all the water it absorbs.

With an average spacing for all fractures of 5 feet and an average 

opening of 0.01 inch, the saturated fractures in 1,000,000 cubic feet of 

rock, equivalent to a depth of 100 feet for a surface area 100 feet 

square, would bold 833 cubic feet of water, which a well with a capacity of 15 gallons a minute could pump out in seven hours if there 

were no renewal of the supply.

These figures are sufficient to indicate that the area contributing to 

any one well must be very large to maintain a constant level for the 

water in the well. Owing to the shape of joints and the manner in 

which they intersect one another this contributing area will be in the 

form of a number of long and comparatively narrow intersecting 

belt§, and the well will draw water from very long distances. Wells 

on islands surrounded by salt water have been successful in obtaining supplies of fresh water, but they are usually moderate in yield 

and frequently somewhat contaminated by salt water, so that as a 

general rule fresh water obtained in these locations consists of that 

which has fallen on the island itself. Fuller,0 however, cites a well on 

Fishers Island, 3 miles from the Connecticut coast, that penetrated 

281 feet of unconsolidated gravel, sand, and clay in which salt water 

was found, and obtained fresh water in the crystalline rock below. 

No outcrops of crystalline rock occur on this island, and it seems 

clear that the fresh water must have come through the joint openings 

from the mainland 3 miles away. The water is evidently held in the 

rock openings by the restraining covering of clay above the rock.

As the head in all the wells is fairly constant, it is evident that 

the yield in any well is proportional to the number and opening of the 

fractures contributing water. As the heaviest yields are derived 

from the most open joints, and as these joints are the most continuous

a Fuller, M. L., Geology of Fishers Island: Bull. Geol. Soc. America, vol. 16, 1905, p. 372.
76 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

(see pp. 66-67), the following relation holds: The yield of water from 

a joint is proportional to its continuity, which depends partly on the 

number of intersecting joints and which consequently determines the 

area contributing to the wells. If this relation is true, and the yield 

is proportional to the contributing area, it follows that there will be no 

permanent change of head in the well until the amount withdrawn 

by the well is greater than the annual absorption of rainfall throughout 

the contributing area. This statement may be made in another way: 

When a small amount of water is pumped from a well the contributing 

area is small, but as larger amounts are pumped the contributing area 

is increased and the more remote connecting joints give their contribution to adjust the difference of level caused by the tendency 

towarcj depressions of the water level in the immediate vicinity of the 

well. Owing to Motional resistance to flow there will, of course, be 

some depression at this point, but it is probably relatively small. 

When the amount withdrawn by the well annually is greater than the 

amount annually absorbed by the contributing area the water level 

in each connecting joint is lowered and a permanent lowering of the 

water level results. As any lowering of the water level means a loss 

of head for the well, and as the head determines the rapidity of flow 

into the well, it is evident that when the water level is lowered the 

yield of the well will immediately decrease.
GROUND WATER IN CRYSTALLINE ROCKS. 

TABULATED WELL RECORDS.

77

The following tables, with the notes succeeding them, comprise 

the information obtained regarding the wells in the crystalline rocks. 

Logs of four of these wells are shown graphically in figure 14.

Loam and hard pan....

Soft rock (disintegrated) .......... ... 10

Soft, pulpy micaceous 

schist................ i6

15 Water. 

20

78 Chief supply.

Clay................... 15

Clay and small stones 

(till) ................ 10

Dark, gravelly Pleistocene drift......... 46

Loose blocks of rock. 29

Soft, dry. decomposed 

rock................. 10

Hard rock (limestone) 5

30 Water (2 gals, 

permin.).

110 Water (15 gals. 

115 per min.).

Gravel and bowlders.............. 34

Micaceous rock.... 41

Gray and yellow 

schist .......... 140

34

38 Small supply.

48 Large supply; 

slightly salt.

200 Supply; very 

salt.

Filling.............. 5.5

Silt.................. 4.5

Coarse gravel...... 13.5

Hardpan............ 13

Granite or liard 

gneiss............. 25

Slate................. 5

Granite or hard 

gneiss............. 5.5

5.5

10

54.5

78.5

159.5

164.5

170

FIGUEE 14. Logs of wells in crystalline rocks. 1, Well of Thomas Fogarty, Ansonia; data furnished by 

C. F. Underwood. 2, Well of Miss E. O. Wheeler, Sharon; data furnished by A. J. Corcoran. 3, Well 

of Atlantic Starch Works, Westport. 4, Well of Sidney Blumenthal Company, Shelton; data furnished 

by the company.
78 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

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21

22

23

24

25

26

27

28

29

ofl

31

32

33

34

35

36

37

38

39

40

41

AO

43

44

*45

*46

47

48

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

pot.

Heights.

etery Assoc.

N. N. Hill. ......

trict. 

N. N. Hill Brass

Co.

F.S. Hall. ......

Mrs. I. H. Stone.

Dr.E.B.Craigin.

Danl. W. Williams. 

Chas. N. Taintor

H.D. Northrop. .

Geo. N. Frost. . . .

IChas. H. Brtin-

\ dage.

V. B.Buck......

G. H. Knapp... .

Geo. P. Brett....

Soldiers. 

.....do...........

HU1. ..........

.....do.........

.....do.........

Slight elevation.

Hill...........

Hilltop........

Hill...........

.....do.........

Plain..........

Slope..........

}... .do. ........

Hill...........

Plain..........

Hilltop........

Small Valley ..

.....do.........

8

13

6

6J

1

6

7

22

16

10

10

10

1J

6

0

3

4

6

12

30

13

12

27

162

48

42

29

121

23

14

142*

185

92

67

30

AAi

48

68

69

108

65

40

152

180

490

413

35

175

54

48*

38

30

127

30

36

149i

201

81

102

77

40

46

54

68

72

112

71

52

182

230

sas

425

126

200

35

174

35

25

40

20

28

142J

185

90

First

at 55. 

40

44

51

62

220

400

335-425

2

4

7

18

4

3

22

9

12

17

16

18

15

30

6

12

20

20

15

Flows+7

18

Additional details concerning wells marked * are riven on pp. 90-91. 
Records of wells in crystalline rocks of Connecticut 

1

49 

50

51 

52 

53

54

55 

56

57 

58

59 

60 

61

62 

63

64 

65 

66

67 

68

69 

70

Town.

East Haddam. 

.....do......... 

.....do.........

.....do.........

East Haven...

.....do.........

.....do.........

....,do.. .......

Greenwich..... 

.....do.........

.....do.........

.....do......... 

.....do.........

.....do.........

.....do.........

Locality.

.....do......... 

Moodus........

Fair Haven....

Crescent Beach

Southport ..... 

.....do.........

Greenfleld hill.

Sound Beach..

Owner.

William Zeigler .

Derby and Ansonia Brewing Co. 

H. Weinstein.... 

Alien Willey..... 

F. B. and S. P. 

Clark.

Andrew Holleran 

Andrew Champion.

E. F. Wheeler...

Essex Wood 

Turning Co. 

J. H. Perry......

Miss Frances 

Wakeman.

G. E. Starkweather. 

A. A. Marks.... .

Mrs. A. W. Mansfield. 

H. O. Havemeyer 

Win. S. Todd....

John Mahar...... 

Jaynes Parh .....

Topographic 

position.

Valley plain. . .

Slope. ......... 

.....do......... 

.....do.........

Hill...........

Coast, elevation 10 feet.

Hill...........

River flat......

Small elevation 

Hill...........

Slope, elevation 30 feet. 

.....do.........

Hill...........

.....do......... 

Slope..........

Slope.......... 

Base of hill....

Depth to rock.

Ft. 

Small

80

30 

3 

4

0

39

28 

11

10

9

0 

65 

21

35 

10

22 

8

Depth of rock.

Ft.

85

70 

57 

36

100

29

66 

114

158

13

20 

235

im

140 

133

178 

52

Depth of well.

Ft.

165

100 

60 

40

100

66*

68

94 

125

168 

190

22 

12

20 

300 

120

175 

143

200 

60

Depth of principal source.

Ft.

99 

55

75

65

80 

110

160

18 

10

18 

240 

50 

150

160

48

Depth to water.

Ft.

30 

53

5

20 

30

10 

10

4

3

8

50 

10

Flows. 

Flows.

V

o

P 

l

Sl

f

p

C
»!H *75 

W

W 76

81 

*82

83

87

90

98

.....do.........

.....do.........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

Guilford.......

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do.. .....

.....do........

.....do........

.....do........

Shelton.......

.....do........

.....do...........

E.W.Bullinger..

J.G.Bill........

J. Hunt Smith...

.....do...........

Damon.

J. F. & N. D.

Sevin. 

Capt. T. Hamilton.

G. W. Maxley...

ern. 

Fred Butler.....

N. E. Wordin.. .

.....do...........

Mrs. G. B. Mitchell. 

Eng. Fish.......

.....do..........

E. L. Webb.....

Edw. W.Bill....

thai Co. 

Oscar Wright....

Hill...........

.....do........

Elevation 20

feet. 

Hill...........

.....do........

.....do........

.....do........

.....do........

tion 100 feet. 

Hill...........

.....do........

.....do........

Hill...........

.....do........

.....do........

Hillside.......

.....do........

.....do........

Hill...........

.....do........

Valley.........

0

0

4

6

9

20

15

12

20

0

12

25

6

12

11

4

li

2

6

0

3

16

73

25

Wfi

265

249

56

55

95

45

74

538

30

38

30

60

50

36£

52

45§

68

?11

43

57

85

Q71

76

225

265

253

62

/30

\60 

64

115

60

86

548

30

50

290

100

55

43

66

62

47J

56

47

70

217

43

60

101

170J

96

60

}.......

50

100

40

86

28-40

280

90

60

60

47

52

45

30

65

96

22

12-20

40

30

10

6

10

8

6

30

30

40

8

25

20

«*

35

4

8

28

6

Sai

var

tid

Ra

low

to 3

lo

...d

...d

do

lo

Average. 6 T
Records of well in crystalline rocks of Connecticut C

0

z

99 

100

101 

102

103 

104 

105 

106 

107

*108 

109 

110

111 

112

113 

114

115 

110

Town.

Killingly......

.....do........

Middletown . . . 

Milford........

....do........

.....do........

.....do........

.....do........

.....do........

.....do........ 

.....do.........

....do.........

.....do.........

Locality.

North Madison

Higganum.....

Naugatuck 

Junction.

Stepney Depot.

New Canaan . . 

.....do.........

Owner.

G. A. Wilcox....

Connecticut Agricultural College. 

Inocente Tolette.

A. B. Curtiss.....

chard.

T. W. Hall......

A. J. Gray.......

B.Fischer estate. 

L. P. Child......

L. D. Alexander. 

C. F. Diefenteler

Sturgis Coffin

Bradley.

Topographic 

position.

Rockyhill ..... 

Hill...........

.....do........

.....do........

Flat...........

Slope. ......... 

.....do........

.....do........

Hilltop........

Ridge......... 

Hill...........

Ridge.........

Hill........... 

.....do.........

Depth to rock.

Ft.

8

4 

9

18 

30 

0 

7 

20

24 

20 

54

35 

60

56 

50

Depth of rock.

Ft.

55

68 

841

132 

45 

43 

32 

80

50 

145 

50

215 

93

94 

203

g^ Depth of well.

1 8U

63

72 

850

150 

75 

43 

39 

100

52J 

165 

104

130 

156

248 

153

150 

253

Depth of principal source.

Ft. 

}.......

63

800 

125

125

240 

153

Depth to water.

Ft. 

0

8

36

8 

30 

6 

12 

15

2 

18 

30

....... ^..

15

18

4 

8

Va

of 

le

Pum

lo

sli

Pu

dr

Con

...d

Con

...d

Con

P u 

low

P u 

low

50 
117

118 

119 

120 

121

122

123 

124

125 

126

127 

128

129 

130 

131 

1-132

^133 

134

135 

136

137

138 

139 

140 

141 

142

143

1=144 

145

146 

147

.....do......... 

.....do.........

.....do......... 

.....do.........

New Milford....

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

Norfolk........

.....do.........

North Canaan

.....do........

.....do........

.....do.........

.....do.........

.....do.........

.....do......... 

.....do.........

.....do......... 

.....do.........

.....do.........

.....do.........

Plainfleld...... 

.....do.........

.....do......... 

.....do.........

.....do......... 

.....do.........

Boardman..... 

.....do.........

East Canaan.. 

SouthNorwalk

....do..........

....do..........

Taftville.......

.....do.........

.....do......... 

Norwichtown .

West Haven...

Woodmont. . . . 

.....do.........

Dr. P. H. Williams.

Miss C. A. Bliss. . 

Theodore Terr ill . 

Con s o 1 i d a t e d 

Street Ry. Co. 

H.H. Hartwell..

Mrs. O. W. Hoyt.

Henry S.S.Kinnlin. 

W.D. Black....

Benj. Hough tailing. 

New England 

Lime Co. 

C. G.Morris.....

A. P. Curtiss... .

R. C. Burr......

Jos. Himmel.....

Norwalk Iron 

Works Co. 

Meeker Union 

Foundry Co.

Co. 

Montville Street 

Ry. Co. 

Frich Co. ........

P. Dion..........

AnthonyMurphy 

Harriet M. Howland.

Ridgely Larkin..

John W. Merwin. 

J. I. Doolittle....

J. C. Noyes.. ....

All Hallows 

Church Corp.

.....do.........

Hilltop........

Elevation2feet 

Slope. ......... 

.....do.........

Hill...........

.....do.........

Valley.........

Hill...........

Island, elevation 8 feet. 

Valley.........

Valley, elevation 4 feet. 

Valley.........

Foot of hill....

.....do.........

Hill...........

.....do.........

Hillside.......

Hill.... .......

Slope, elevation 30 feet. 

Hill...........

Plain..........

Slope.......... 

.....do.........

48J

65f 

20 

14 

60

5 

"5

13 

5

30 

49 

18

80

20

0 

11 

0 

2 

80

20

13 

1

10

151?

87] 

130 

172 

73

60

38

57

44 

45

78 

17 

19J

95

265 

42J 

75 

101 

125

54

237 

56

90

200

153 

150 

186 

133

65

60 

62

250

57 

50 

20

108 

66 

37J 

125

260 

107 

247

115 

200

265 

50i 

75 

103 

205

74

250 

57

100 

117

60

55 

40

30 

20

60 

100

80 

190 

170

60

74

- 230 

30-35

40

5

20

4

9

2

5

25

10

""""so"

7

4-20

11

15

15

8

6

5

10

15

10

100

30

15

16

10

10

50 

Few feet.

18 

..........

lo

80 

su

lo

fe

Pu

lo

....

a No water above 150 feet. 
Records of wells in crystalline rocks of Connecticut 

1

148

149

150

151

15?

153

1 <*A

155

156

*157

158

159

161

162

164

165

166

Town.

.....do.........

.....do.........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do.........

.....do.........

.....do.........

Locality.

.....do........

Heights.

.....do.........

Owner.

W. H. Wilson....

Plainfield Woolen Co.

Terryville Water

Co. 

Mrs. M. V. Clark.

ielson. 

Dr. E.M.Harris.

G. A. Pettis......

Co.

\V \V Jsmiiiiss

Mrs. J. W. Spencer.

Warner.

Topographic 

position.

Hill...........

.....do.........

Valley.........

Hill. ..........

.....do........

.....do........

HU1. ..........

.....do.........

Hill...........

.....do.........

.....do.........

Depth to rock.

Ft. 

13

12

30

30

18

98

84

55

18

18

7

52

10

30

22

Depth of rock.

Ft. 

18

43

13??

70

59?

7

?8

365

6?7

94

78

96

205

48

52

Depth of well.

Ft. 

33

55

55

1fi?f

531

100

610

105

11?

4?0

645

11?

85

148

486

78

88

74

?80

"C aJ 

*1

0 0

.cCS 

ft.&SrS

Q

Ft. 

30

40

160

100

600

55

110

65

138

Ortrt

68

88

70

Depth to water.

Ft.

10

20

Flow.

Flows +3

25

43

30

20

4

30

20

15

2

20

12

Va

of 

le

Var

Var

c

ly 
168 

169

*170

171

172 

173

174 

175

*176 

177

178 

179

180 

181

182 

183

184 

185 

186

187 

189 

190

191 

192

193

194 

195

196

.....do......... 

Sharon ........

.....do.........

Sherman ......

.....do.........

.....do......... 

.....do.........

.....do.........

.....do......... 

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do........

.....do.........

.....do......... 

.....do.........

.....do.........

.....do.........

"Baltic.'!.'.'!."!.'^

.....do.........

.....do......... 

Hanover.......

West Stafford .

................

Sound Beach. .

/North Grosve- 

\ nordale.

Willsonville...

Jas. Swan........ 

C. A. Low.......

MissE.O.Wheeler. 

Geo. A.Barnes...

St. Mary's R. C. 

Society. 

Dr. S. Bouvier... 

Angus Park. ... . .

Ralph Brown.... 

H. S. Cammann. .

Patrick Boyle.... 

Dr. A. J. Givens.

Clendenin Echert 

Diamond Ice Co..

.....do...........

Mr. Dobbs.......

Mrs. J. R. Chesebro. 

A twood-Morrison 

Co.

J. N. Kingsbury .

N. B. Ream.....

Grosvenor Dale 

Co.

Jos. Brault....... 

S.A.Hermann ..

Excelsior Needle 

Co.

Slope.......... 

Hill...........

.....do......... 

Hill...........

.....do......... 

.....do.........

.....do......... 

Hill...........

Plain, elevation 20 feet.

Shore.......... 

.....do.........

Slope. .........

Slope, elevation 30 feet.

Hill...........

.....do.........

.....do.........

Hill...........

Walley ........

Slope..........

Hill........... 

.....do.........

Valley.........

""25" 

100

12 

3

27 

30

21

30

25 

50

50

3

28

7

15 

13

15

0

7 

35

43

i4e'

15

58 

38

31 

50

26

382

161 

120

42

98 

143 

45

60 

37

275

53 

39 

79

540

280 

171

115

70 

41 

175

58 

80

47 

177

102 

412

186 

170

92 

70

101 

171 

52

75 

50 

310

60

290

53 

46 

114

583

60

110

50 

15-25

56 

75

47 

177

78 

30 

40

15-40

33

112 

500-583

12 

20

70

20 

3 

Flows.

2 

30

22 

15

52

29 

15

7

12-18 

4 

25

10 

4

10 

6

8

....

Con

...d

P u 

lo

30 

P u 

lo

P u 

lo

50 

P u 

lo

Sea

P u 

lo

sl

IP u

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Dr

Co

P u 

lo

to 
Records of v:ells in crystalline rocks of Connecticut C

fc

197

198

199

200

201

*202

203

204

205

206

207

208

209

210

211

212

213

Town.

.....do.........

.....do.........

.....do.........

Vernon. .......

.....do.........

.....do.........

.....do.........

.....do.. .......

.....do.........

.....do.........

.....do.........

.....do.........

Locality.

Roekville......

.....do.........

Talcottville....

-

Owner.

Thos. J. Stone....

Co.

N. B. Curtis.....

E.S.Fairchild...

Thos. L. Wade...

B. L. Burr.......

Horace G. Holt..

Talcott Bros.....

.....do......'.....

Dr. H. H. Hartwell.

(Waterbury Brass

\ Co.

Platt Bros..:... .

Co.

chine Co.

/Waterbury Mfg.

\ Co.

Topographic 

position.

Valley.........

Slope..........

Hill...........

Slope..........

.....do.........

Flat...........

Slope..........

JV alley ........

.....do.........

Valley.........

.....do.........

jsiope .........

3

&

P

Ft.

23

50

18

30

16

6

25

97

17

5

80

10

60

48

0

20

'o

'ft

O)

P

Ft.

75

54

3?

45

69

54

7

230

33^

60

80

74

141

fi5

330

*s

'ft

O)

P

Ft.

98

104

50

75

85

60

32

327

50J

50

65

160

93

180

189

65

350

£

Qj S

°1

&*£

ItP°

Ft.

65

90

48

50

75

58

50

49

160

80

185

55

300

s

ts

a

'&

O)

P

Ft.

8

9

8

0

25

46

32

13

13

5

13

8

9

30

2

3

Va

of 

l

Low

30 

Sea

P u 

lo

40 

P u 

low

...d

P u 

low

Con

...d

(Pu

 Mo

1 som

Pum

low

Con

wi

pu

Con

Pu

lo
214

215

216 

217 

218 

219

220 

221 

222 

*223 

224 

225 

226

*227 

228

229 

230

231

232 

233 

234 

235 

236

237

.....do.........

.....do.........

Waterford..... 

.....do.........

.....do.........

.....do.........

Westbrook .... 

.....do.........

.....do.........

.....do.........

.....do......... 

Wilton........

Winchester. . . .

.....do.........

.....do.........

.....do.........

Pleasure Beach 

.....do.........

Saugatuck. ....

Winsted.......

Franklin H.Kalbfleisch Co.

.....do...........

.....do...........

John O. Enders..

Maj. H.A.Hull- .

AngelineW.Hill. 

Mrs.J.H. Ripley.

/Atlantic Starch 

\ Works.

Hammond. 

A. W. Smith.....

HollandMfg.Co.. 

Geo. D. Watrous . 

Edwin Judge.. ..

W. J. Lum.......

HilJ. ..........

.....do.........

Plain, elevation, 80 feet.

Slope..........

HU1.. .........

.....do.........

.....do........ 

.....do.........

.....do.........

} Valley.. ......

Hilltop........

Valley.........

Hill...........

Valley......... 

Hill...........

.....do.........

50

14

10 

14 

20

18

17 

7 

58 

6 

0 

10 

3

34 

30

15

16

5

0 

15 

20

. 9

36

23

32 

48 

11 

100

63 

36 

15

45 

87 

90

47

181 

118

79 

10

95

15 

15 

44

141

86

37

42 

62 

31 

118

80 

43 

73 

51 

87 

100

£0

215 

148

94

26

100

75

15 

30 

64

150

27

80

13 

40 

35

/ 45 

\ 50

f 48 

\ 200

20 

35

12

54

27

7

7 

4 

11 

16

11 

12 

26

60 

} 4 

}.........

30 

10

4 

15 

7 

10 

12

Flows 11

Pu

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2 

Pu

l

Pu

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s
Additional records of wells in crystalline rock of Co

[Furnished by C. L. Grant.]

No.

1

2

6

7

8

10

11

1 ^

14

15

16

17

IS

19

20

01

23

24

26

27

29

OA

31

32

OQ

34

oc

36

V7

38

OQ

40

41

42

43

Town.

.....do.........................

.....do.........................

.....do.........................

Bristol........................

.....do.........................

.....do.........................

.....do.........................

Milford........ ................

.....do.........................

.....do.........................

.....do..........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

Plainfleld.. ...................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

Locality.

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

Moosup. ......................

Owner.

Wm. F. Clark... .........................

Maltby, Stevens & Maltby . . .............

Bristol Brass & Clock Co. ................

S. H. Bowen.............................

H. P. Chandler..... ......................

Mrs. E . P. Smith .........................

J. W . Kelly ..............................

Mrs. A. M. Bradley. .....................

......do....................................

N. D.Sewin. .............................

R. S. Griswold. ..........................

.....do...................................

.....do....................................

Nelson W illett ...........................

J. W. Atwood... . ........................

W. H. Wilson. ... ........................
44

45

4fi

47

48

AQ

50

51

5?!

CO

KA

55

56

57

58

59

60

61

fi9

63

64

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

.....do.........................

Joseph Potwin ..........................

.....do...................................

.... .do..... . .............................

E E. Salisbury .........................

J. A. Paine... ...........................

Patrick Ryan ...........................

Win. H. Smith. .........................
90 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

NOTES.

2. Penetrated 20 feet of loam and hardpan, 10 feet of soft rock, 20 feet of hard rock, 

and 46 feet of soft pulpy micaceous rock. Water was obtained in the soft micaceous 

rock. (See fig. 14.)

7. Dug and blasted 28 feet and drilled 22^ feet. Passed through 2 feet of loam, 12 

feet of till with a 1-foot layer of iron-cemented material, 14 feet of disintegrated rock, 

and 22f feet of hard rock.

10. Water salty on first being pumped but becomes fresh with continued pumping.

18. In drilling, considerable amounts of water were encountered in the sand and 

gravel above the rock. This water was cased out and a small amount was found at a 

depth of 25 feet in the granite, and additional supplies, increasing in small amounts, 

were found down to a depth of 150 feet. Below this point no new supplies were 

encountered, although the total depth of the well is 315 feet. The material penetrated 

was as follows: Sand and gravel, 50 feet; granite, 100 feet; clay and gravel (probably 

disintegrated rock marking a shear zone), 20 feet; soft white micaceous rock followed 

by granite varying in hardness every few feet (probably gneiss).

45 and 46. Maj. William Spittle has furnished the following information: One well 

was drilled to a depth of 425 feet through 12 feet of clay till and 413 feet of granitic 

rock, of nearly the same character for the entire depth, probably a gneissoid granite. 

Water first began to flow over the surface at 335 feet from the top and continued to 

increase slowly in the amount of flow and in the height of the rise above the surface 

with increasing depth. At present the water will rise at least 7 feet above the surface 

of the well in a f-inch pipe. In five months' continuous flowing the volume of water 

decreased from 4 to 3 gallons a minute. When pumped the well yielded 50 gallons a 

minute and the water level was lowered to 80 feet below the surface and remained 

steady. The second well was sunk 130 feet away and at an elevation 4 feet higher to 

a depth of 503 feet. This well yields 25 gallons a minute, but the water stands at a 

level 15 feet below the surface. The pumping of the second well did not affect the 

yield of the first.

75. Mr. H. B. King has furnished information regarding five wells drilled for the 

Aspinook Company at Jewett City. They are from 15 to 100 feet apart and from 30 

to 60 feet in depth, all penetrating 6 to 8 feet of sand and gravel. They are located 

on a hillside at varying elevations. These wells each average 20 gallons a minute and 

are all connected to a siphon which conducts the water to the mill at an elevation about 

75 feet lower than the wells. Two of these wells, 15 feet apart, affect each other's 

yield, but the remaining wells are apparently independent of one another.

80. A small stream of water was encountered at 83 feet from the surface, and at 180 

feet a stream of 1 gallon a minute; below this there was no increase in supply to a 

depth of 530 feet.

82. At a depth of 32 feet this well yielded 1 gallon a minute and at 38 feet 4 gallons 

a minute. The last 10 feet of the well gave no increase of supply.

97. Filling, 5.5 feet; silt, 5 feet; coarse gravel, 13.5 feet; coarse sand, 36 feet; hardpan, 13 feet; gneiss, 62 feet; granite or hard gneiss, 25 feet; slate, 5 feet; granite or 

hard gneiss, 5.5 feet. The total depth of the well is 170.5 feet. (See fig. 14.)

108. On the slope of a hill near the base of which are numerous springs. The water 

is siphoned from the well to tenement houses below. In dry seasons the level of water 

in the well drops 2 feet.

132. Drilled on a small island in Long Island Sound. A trace of fresh water was 

obtained at 125 feet, hut the remaining supply was salty.

133. Fresh water was obtained at a depth of 60 feet, evidently from gravel deposits, 

but salt water was encountered in the rock seams below this point. The well was 

plugged below 60 feet and the fresh water from the gravel is utilized.
GEOTJND WATEE IN CBYSTALLINE EOCKS. 91

144. No water was found in the first 100 feet. In the next 70 feet a small amount 

was obtained, possibly 40 gallons a day, and the water stood at a level 107 feet below 

the surface. The well was drilled to a depth of 250 feet and an excellent supply 

obtained at 230 feet below the surface. Information furnished by H. B. King, the 

driller.

157. The water comes from the contact of the overlying clay and the solid rock. 

No water was found in the rock, which is a quartzite schist, although 365 feet of rock 

were penetrated.

170. The following log is furnished by the driller, A. J. Corcoran: Solid clay, 15 feet; 

clay and small stones (till), 10 feet; dark gravelly material, 46 feet; loose blocks of 

rock, 29 feet; soft and dry decomposed rock, 10 feet; hard rock, 5 feet. A small 

yield of water, 2 gallons a minute, was found at a depth of 30 feet, but no more was 

encountered until the last 5 feet of hard rock was penetrated, when a supply of 15 

gallons a minute was obtained. (See fig. 14.)

176. Water was found in the superficial drift, but was lost on encountering a dry 

seam in the rock.

202. A good supply of water was obtained at a depth of 25 feet, but this flowed off 

at 45 feet, and when water was struck again at 60 feet it rose to this point and flowed 

off in the open rock seam.

223. At 35 feet the well pumped 100 gallons an hour and the water rose within 16 

feet of the surface. A second and very large supply was encountered at a depth of 

51 feet and the level of the water dropped to 25 feet below the surface.

227. Penetrated 34 feet of gravel and bowlders and 41 feet of micaceous rock, in 

which a little fresh water was found at 38 feet below the surface and a large flow of 

slightly salt water at 48 feet below the surface. The rest of the well was through a 

rock described as gray and yellow sandstone (probably schist). At 200 feet very salt 

water was encountered, but this is held back by a plug. (See fig. 14.)

PRACTICAL APPLICATIONS.

PERCENTAGE OF FAILURE OF WELLS.

Wells in crystalline rocks are unlike most other wells, in that it is 

impossible to predict their success or failure, even when numerous 

wells have been sunk previously in the same locality. For this reason 

a well driller will rarely guarantee to obtain water from such a well, 

although occasionally water is guaranteed and an additional price 

per foot charged to offset the driller's risk of failure.

When a well is considered a failure the fault lies either with the 

quality or with the quantity of the water obtained. It is a very 

exceptional well in which no water supply is obtained in the rock. 

Nearly all wells encounter some water in the surface material above 

the rock, but it is common for the drill to penetrate 30 or 40 feet of 

rock, and occasionally even 100 feet, without obtaining enough water 

in the rock to keep the drillings wet, so that water must be poured 

in at the top to allow the drilling to continue. Although no satisfactory data are at hand regarding the number of wells which have 

failed to obtain any water, it is certain that the number is very 

small. Among 237 wells only 3, or 1.25 per cent, are recorded as 

obtaining no water. Drillers are naturally averse to giving infor-
92 UNDEEGKOUND WATEK EESOURCES OF CONNECTICUT.

mation regarding unsuccessful wells which they have sunk, but the 

available information indicates that, though dry wells are uncommon, 

there are a considerable number of wells in which the yield of water 

has been less than 2 gallons a minute. For certain purposes, such as 

manufacturing, this small supply would be considered a failure, but 

for domestic use where the water is obtained by a hand pump or 

windmill a supply of this amount is generally sufficient. Among 134 

wells whose yield is known, only 17, about 12.5 per cent, furnish less 

than 2 gallons a minute. It is probably a conservative estimate to 

state that not less than 90 per cent of the wells sunk in the crystalline rocks have given supplies of sufficient amount for the use required.

The greater number of unsuccessful wells in regard to quality are 

located along the coast or on tidal rivers, where the well supplies are 

affected by sea water. When a well is within a few hundred feet of 

salt sea water, it sometimes happens that salty or brackish water is 

obtained, although perfectly fresh water is yielded by other wells in 

similar locations. Six wells are recorded in which the water has been 

contaminated in this way and others, regarding which definite information is lacking, are known to have been failures for the same 

reason. It is certain that a large percentage of wells near salt water 

have yielded brackish water and any well sunk in rock on a small 

island or within 500 feet of the sea is likely to afford an unsatisfactory supply. As nearly as can be estimated from present information, the chances of failure for such wells are between one in four 

and one in three.

When there is a choice of several locations, the well should be as 

far as possible from the sea and at as high elevation as convenient. 

Several wells that have been ruined by the entrance of salt water 

are situated on old salt marshes or on filled ground that is but 

slightly elevated above tide level. In the quarry at Millstone Point, 

near New London, which is about 150 feet from the sea, brackish 

water enters through the horizontal seams in the upper part of the 

quarry wall nearest the Sound. The rock outcrops in the sea and 

the open seams have abundant opportunity to absorb salt water.

VARIATIONS IN YIELD AND DEPTH.

The depths and yields of wells vary widely within very small 

areas. When considered collectively, as in the table on page 102, it 

is seen that there is an average increase in the amount of water 

obtained with increase in depth of the wells. It is often found, however, that of two wells sunk within 100 feet of each other in the same 

kind of rock, one will obtain a plentiful supply of water while the 

other may be sunk to twice the depth and obtain only one-tenth the 

amount. This is a typical case which nearly every Connecticut well
GEOUND WATEK IN CRYSTALLINE ROCKS. 93

driller will present in one form or another when information regarding his drilling experiences is requested.

This variation within short distances is due to the varied occurrence of the water-bearing fractures considered on the previous pages. 

One well may be sunk in a portion of the rock in which the fractures 

are numerous and closely spaced or it may intersect a large open 

fracture; the second well, only 100 feet away, may be located in an 

area of widely spread fractures or it may intersect only fractures 

with closely compressed walls and consequently can obtain only a 

meager water supply. Owing to the general steep pitch of joint 

planes, there would be little chance of two wells intersecting the 

same fracture, although they might possibly intersect connecting 

fractures and in this way affect each other's yield. Even where two 

wells intersect connecting fractures at the same depth, the yield of 

the two wells would probably be different, owing to differences in the 

opening of the fractures.

LIMIT OF DEPTH FOR WELLS IN CRYSTALLINE ROCKS.

Although the well records given on pages 78-89 show that supplies 

of water have been obtained at all depths from 15 feet to 800 feet, the 

largest percentage of failures is among the wells more than 400 feet 

in depth. The reasons for the increasing probability of failure with 

increasing depth are indicated in the discussion of joints (pp. 61-64), 

where it is shown that increased depth means a decrease in number 

and a tightening of joints. Increased depth usually means an 

increase in the cost per foot, as drilling is necessarily slower and consequently more expensive at considerable depths. Owing to the 

great length of rope and the necessity of waiting for the recoil of the 

stretched rope fewer blows can be struck per minute and there is 

also greater danger of losing the drilling tools.

In view of the increasing cost and the decreasing probability of 

finding water-bearing seams with increasing depth, and of the great 

variation in water-bearing fractures within very short distances, it 

seems manifest that if a well is unsuccessful within a certain depth 

the best policy is to abandon the well and start a new one at some 

distance from the first. In one place a well was abandoned in this 

manner and a second and successful one sunk by simply turning the 

rig around and drilling a hole less than 20 feet away. It is always 

preferable, however, to move as far away from the first well as 

possible.

In deciding at what depth an unsuccessful well should be abandoned a number of factors must be taken into consideration, but an 

estimate that will prove of value may be made from the available 

well records. The table on page 100 shows that the average depth
94 UNDEEGEOUND WATEE EESOUECES OF CONNECTICUT.

of the wells varies considerably for different rocks. The average 

depth in rock of 163 wells is 88.8 feet and the average total depth, 

including the surface material overlying the rock, is 108.4 feet. 

About 90 per cent of the wells are under 300 feet in depth and 82 

per cent under 200 feet. In many of the wells which have gone 

below 250 feet the main supply and in several the entire supply has 

come from seams less than 250 feet in depth. From a study of the 

recorded wells it would appear, therefore, that if a well has penetrated 250 feet of rock without success the best policy is to abandon 

it and sink in another location. For wells in granodiorite, which 

have been successful at an average greater depth than in other rocks, 

this depth might be somewhat too small, but for wells in other rocks 

it is possible that a maximum depth of 200 feet should be adopted. 

The wells that penetrate 200 feet or less of rock show a rather 

regular increase in yield of water with increasing depth, but in deeper 

wells than this the tendency is toward a smaller average yield owing 

to the failure of many of the wells. The average yield of 123 wells 

in the crystalline rocks is 12.7 gallons a minute, and as their average 

depth is 108 feet the cost of the average well for this yield of water 

at $4.25 a foot is $459.

QUALITY OF WATER.

A general discussion of the chemical composition of well waters 

and a number of analyses of well waters derived from crystalline 

rocks may be found on pages 166-168, 176-179. The general quality 

of water from these rocks is excellent and they are well adapted to 

boiler use.

TEMPERATURE OF WATER.

The temperature of the water is entirely dependent on the depth 

from which it comes. In wells less than 50 feet deep the water will 

show variations in temperature agreeing in a modified form with the 

seasonal,changes. In wells more than 50 feet in depth the temperature of the water increases at the rate of about 1° to every 60 feet 

of depth. The average temperature of the water of 49 wells in the 

crystalline rocks is 50.5° F. The average annual temperature of Connecticut is 47° F.

LOCATION OF WELLS.

So many factors are involved in considering the location of a well 

that it is impossible to lay down any set rule for choosing a location. 

Before sinking a well it is always advisable to find out what wells 

have been sunk in the vicinity an4 what success they have had. 

The list of well records on pages 78-89 gives all the information at 

hand, although there are probably as many more wells in Connecticut regarding which no information has been obtained.
GEOUND WATEE IN CRYSTALLINE BOOKS. 95

In localities where, owing to limited space or other factors, there is 

only one place where a well can be sunk, the only questions to be 

considered are the possibility of obtaining a satisfactory supply and 

the probable cost. For such wells the information embodied in this 

report should be of considerable value.

Where there is a choice of situations for the well the following 

points should be considered. The well should be as far removed 

from contaminating influences as possible. This is particularly 

important for wells near sea water. (See p. 174.) It is better to sink 

the well where there is a heavy covering of surface material rather 

than on a bare rock ledge. If there are rock exposures near by, a 

study of the joints may be of assistance in locating the well so as to 

intersect possible water-bearing fractures.

The Aspinook Company, at Jewett City, has adopted a very successful scheme which doubtless could be used in many other places. 

The mill is located below a hill and a series of wells were sunk on the 

hillside at a considerable elevation above the mill. The water is 

obtained by means of a siphon and a very considerable pumping 

expense is thus saved. The same method has been adopted for individual wells elsewhere and has proved satisfactory.

In order that a siphon may be used, the water level must be not 

more than 30 feet from the surface a,nd the lower end of the siphon 

pipe or the escape valve must be at an elevation lower than the 

water level. The average depth from the surface of the ground to 

the water level in the recorded wells is 19 feet on hills and 15 feet on 

slopes. The water level will of course lower to some extent when 

water is drawn out and the degree of lowering will be proportional 

to the volume of water removed, but in many wells the lowering will 

not be sufficient to affect the use of the siphon. The greatest certainty of success will be on hillsides where there is a covering of clay 

or hardpan and where there are no outcrops of rock showing above 

the surface at elevations lower than the top of the well.

The wells located on hills average less in cost than those in valleys, 

owing to the greater depth of the valley wells, as shown in the table 

on page 102; but the average yield of wells on hills and in valleys is 

nearly the same.

CONSTANCY OF YIELD.

The wells appear to maintain a remarkably constant yield from 

year to year. Although the drilling of wells in the crystalline rocks 

is a comparatively new venture and almost all of these wells have 

been sunk in the last three years, no well in which water was obtained 

has failed to yield a supply on continued use. In very shallow wells 

dry seasons have marked some decrease in supply, but the decrease 

has been small and only temporary. In a number of wells the sup-
96 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

ply has increased after continued pumping, probably owing to the 

removal of material lodged in the rock crevices, which are cleaned 

out by the running water.

In some wells supplies obtained at short distances below the surface 

have been lost with deeper sinking, an open dry crevice struck at a lower 

level allowing the water to run off. Such occurrences are unusual 

and are found at relatively shallow depths. During the drilling of 

any well it is usual to find a number of fractures supplying water. 

Often the water derived from small sources will stand at a certain 

level in the well and when the main supply is struck will rise or fall, 

depending on the height at which the water stands in the main 

crevice. There will of course be an equalizing between the various 

supplying fractures. If the well penetrates one saturated fracture 

in which the water stands at 10 feet below the top of the well and a 

second fracture in which the water stands at 30 feet below the top, 

the water level in the well will occupy an intermediate point somewhere between 10 and 30 feet below the surface.

FLOWING WELLS.

The question is often asked regarding the possibility of obtaining 

flowing wells in Connecticut. A number of flowing wells have been 

obtained in the sandstone area^in the central and northern portions 

of the State, but a flowing well in crystalline rocks is a very unusual 

occurrence. Information has been obtained regarding six wells in 

the Connecticut crystalline areas in which the water has maintained 

a constant flow over the top for some time and several wells are 

known in which the water has flowed over the surface for a few 

minutes but has eventually lowered to a level below the mouth of the 

well.

The occurrence of flowing wells is therefore common enough to 

demand an explanation. Four of these wells have been personally 

visited and the position of the others is known approximately. Each 

of the wells is located on the side slope of a hill or in a small valley 

where there is a considerable elevation back of the well. One well 

at Greenwich is on a very gently sloping surface so that it appears to 

be at the top of the hill, but in reality the ground rises gradually to 

an elevation at least 40 feet higher than the well. All the wells are 

in markedly glaciated areas, where there is a considerable thickness 

of clay till overlying the rock, and there are no neighboring rock 

outcrops except at one flowing well called the Buttress Dyke Spring, 

near New Haven. This well is in an area of schistose rock where the 

hill back of the well exhibits numerous outcrops, but there are no 

rock ledges showing at elevations lower than the well.

From the study of the individual wells and of the general occurrence 

of water in rock fractures, it is concluded that the artesian conditions
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 232 PLATE III

A FLOWING WELL AT NOROTON HEIGHTS.

B WEATHERING DU-E TO GROUND WATER IN GRANITE QUARRY.
GKOtnSTD WATEK IN" CKYSTALLINE BOCKS. 97

giving rise to flowing wells in Connecticut are due solely to the capping 

of clay till above the rock and that this capping is sufficiently impervious to prevent the water escaping from the rock crevices, at least 

with sufficient freedom to destroy the artesian head. The water 

occupying the rock seams is under hydrostatic pressure owing to its 

confinement on the sloping hillside, and, an easy escape being offered 

by the open well, the water rises to the surface. It is probable that 

the joints that give rise to the flowing wells are more nearly at right 

angles to the slope of the hillside than parallel to it. The same conditions might arise where the joints have a pitch parallel to the 

surface slope and a very low inclination, but the pitch of most of the 

joints is so steep that they would intersect the surface so near the 

well as to give little or no head to the water.

As far as water supply is concerned, flowing wells need not be considered as of any particular importance in Connecticut. In the first 

place it is impossible to predict that a well will flow, even though 

the most favorable location be chosen. At Noroton Heights two 

wells were sunk within 150 feet of each other in the same kind of 

location, one of which flowed 7 feet above the surface, while in the 

other the water rose only within 15 feet of the top. Second, the flow 

at each of the flowing wells has been small, from 1 to 4 gallons a 

minute. This supply is too small for the use made of it at most of 

the wells and pumping machinery has been installed. The wells 

have yielded unusually large supplies when pumped, but the level of 

the water has sunk to a considerable distance below the surface. 

It is not known whether the wells would again flow if pumping were 

stopped. (See PI. Ill, A.)

It is probable that in the wells which flowed for only a few minutes 

after being struck the water then found an escape through open dry 

fractures in the upper portion of the well, as the water level dropped 

to several feet below the surface.

WELLS IN VARYINO ROCK TYPES.

A study of joints and other rock fractures indicates that these 

structures vary with varying rock types, and as the water supply of 

wells is directly dependent on the fractures it is to be expected that 

there will be corresponding variations of supply in the wells in the 

different rock varieties. These variations are discussed below. The 

records on which the discussion is based are not as complete as might 

be desired, but are sufficiently numerous to have considerable weight.

Wells in granite. It has been shown that the fractures particularly characteristic of granite masses are the nearly horizontal joints 

which in general run parallel to the surface of the ground. These 

joints are manifestly of considerable importance in the transmission 

and storage of water, but it is doubtful whether they are sources of 

463 IRR 232 09 7
98 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

large supply to wells. In granite quarries where the horizontal 

joints are well .developed, the greater portion of the water entering 

the quarry conies through these flat joints. Owing to their parallelism to the surface these joints are not in a suitable position to receive 

water from the material overlying the rock, and must get their main 

supply of water from that descending through the vertical joints. 

In the quarry walls the largest amount of water escapes and the 

heaviest decomposition of the rock occurs near the major vertical 

joints, indicating that the vicinity of such joints is the place of greatest 

water circulation. '

As a well sunk in granite must pass through a large number of 

horizontal seams, which are far more abundant in the upper 50 feet 

of rock than in the next 50 feet, it would appear that if these seams 

were saturated and could yield good water supplies the granite wells 

should furnish unusually large supplies at comparatively shallow 

depths.

The records show, however, that the wells in granite yield about 

the same as those in gneiss and schist, and that although their average 

depth is 10 per cent less than that of the wells in gneiss it is slightly 

greater than the average of the schist wells. The natural inference 

to be drawn is that though the number of contributing fractures to 

any one well is much greater in granite than in the other two main 

rock types, the total yield of the well is no greater than the amount 

furnished by the vertical joints to the horizontal joints.

In granite the vertical joints are more irregular and probably more 

widely spaced than in the other rock types, but they are well connected 

with one another by the intersecting horizontal joints. The contributing area to a granite well should occupy a space with an approximately uniform radius around the well.

Wells in schist and gneiss, Little difference can be distinguished 

between the occurrence of joints in schist and that in gneiss, and in 

fact the two rocks grade into each other so completely that it is in 

some places difficult to say whether a rock is a schist or a gneiss.

The marked development of horizontal joints characteristic of 

granite is lacking in these rocks, and the more regular character of the 

vertical joints tends to produce a different manner of circulation 

through the rock. A single well, instead of drawing water from an 

area surrounding it on all sides, will draw from long distances through 

the feeding fractures and the vertical fractures connecting with 

them.

The wells in schist and gneiss have nearly the same average yield, 

but those in gneiss average 15 per cent deeper than those in schist. 

It is possible that the supply for the wells in schist comes not only 

through the joints but also through fissility openings or small fractures parallel to the schistosity. Such fractures are common near
GROUND WATER IN CRYSTALLINE ROCKS. 99

the surface, and owing to their inclination might well absorb considerable volumes of water. Because of the small size and lack of continuity of these openings they would yield water very slowly to the 

well, but might give an important amount in the aggregate. The 

derivation of a supply through such openings, which would have their 

greatest development near the surface, would account for the relative 

shallowness of wells in schist.

That fractures parallel to the schistosity may be important carriers of water is well shown on the east bank of Connecticut River 

above Hadlyme Landing, where there is a long exposure of fissile 

schist and a number of small springs issue from partings parallel to 

the schistosity.

Wells in quartzite schist. In the northeastern portion of the State 

there is an important development of a rock which is a schist but 

is unlike most of the schists of Connecticut and will be treated 

separately. This rock is an altered quartzite and consists very largely 

of quartz grains with a very small percentage of other minerals. No 

study was made of the fractures in this rock, but information has 

been obtained regarding five wells which were drilled in it, three of 

which are more than 300 feet in depth and one more than 200 feet. 

In each one the supply has been very small and unsatisfactory. 

Though the number of these wells is small, the evidence indicates that 

the rock is a very unreliable source of water supply and that the 

fractures are few or poorly developed.

Wells in phyllite. Near Woodbridge and at Woodmont several 

wells have been drilled in a greenish slaty rock or phyllite in which 

the supplies have proved very unsatisfactory. The cleavage of the 

rock is nearly vertical, causing difficulty in drilling, and most of the 

fractures appear to be filled by some cementing mineral matter. 

The wells that have been drilled in this rock are comparatively shallow, but the water obtained has been so universally poor that the 

probability of getting a satisfactory supply appears to be very slight.

Wells in Zwiesfone. Comparatively few wells have been drilled in 

the limestone area in the western part of the State, where springs are 

so numerous as to constitute far the most important source of water 

supply. The limestone itself is largely recrystallized and changed to 

a marble. It is dolomitic in part, but unlike many dolomites is compact and contains very little pore space.

The fracturing is very thorough and in fact so complete that it has 

been found impossible to obtain blocks for building purposes large 

enough to warrant quarrying. The limestone is traversed throughout by irregular fractures which divide it into a series of comparatively 

small blocks. Solution is very effective in limestone, as the calcium 

carbonate constituting the bulk of the rock is readily soluble in 

water containing carbon dioxide. No large solution caverns, such as
100 UNDERGROUND WATEK RESOURCES OF CONNECTICUT.

are typical of many limestones, have been found in the Connecticut 

limestones, but the fractures generally have decomposed borders 

several inches wide and are sufficiently enlarged to offer easy passage 

to water.

Wells should be very successful in this rock, but because of its 

highly fractured condition water passes through it rapidly and the 

level of the water in the wells will probably be at a greater distance 

below the surface than in rocks of other types.

Wells in granodiorite. In the vicinity of Stamford and Greenwich 

the wells drilled in schistose granodiorite have met with a considerable degree of success. The rock outcrops in this area show a -welldeveloped and rather closely spaced jointing which is nearly at right 

angles to the schistose structure of the rock. There is no. apparent 

reason why the wells in this rock should differ from those in schist 

and gneiss, but the average depth and average yield are much greater. 

It is possible that especially large supplies have been required in this 

locality and that for this reason the smaller supplies in the upper 

portion of the rock have been insufficient and the wells have been 

drilled until a large supply was struck.

STATISTICAL TABLES.

TABLE 1. Yields of water at varying depths in the rock below the covering of surface

material.

[" Vol."=average yield in gallons per minute; "No."=nuniber of records from which the average is taken.]

Schist. ..................................

Schist...................................

0-30

Vol.

3.2 

7 

1

3.6

No.

2 

1 

1

4

110-200

Vol.

8.5 

13 

8.3 

46.0

20.2

No.

2 

5 

8 

6

21

30-50

Vol.

6.7 

11.9

9.75

No.

9 

13

22

200-300

Vol.

16 

33.0 

10.7 

0

16.7

No.

3 

2 

3

1

9

50-70

Vol.

9.5 

9.8 

12.4

11.3

No.

4 

5 

14

23

300-400

Vol.

0 

22.0 

2 

2

11.5

No.

1 

2 

1 

1

4

70-90

Vol.

21.6 

20.5 

7.6 

8.0

6.0

12.4

No.

3 

2

7

1

14

400-500

Vol.

0 

50

26,0

No.

1 

1

5

90-110

Vol.

22.1 

14.4 

5.5 

0

15.2

No.

6 

8 

2 

1

17

500-650

Vol.

14.0

7

5.2

No.

2

2

4

NOTE. The information at hand shows no relation between the depth of the surface drift and the yield 

or success of wells.
GROUND WATER IN CRYSTALLINE ROCKS. 101 

TABLE 2. Yield of wells more than 400 feet deep, with reference to topographic position.

Location.

Hills.................................................... ......................

Depth in 

feet.

( 583 

1 690

1 503 

I 425 

850 

548

420 

486 

610

645 

1,465

Yield (gallons per 

minute).

25 

olO

50 

40 

Poor.

2 

Dry. 

12

63

All water obtained at 120 feet. 6 Salty. 

TABLE 3. Average yield of wells in various locations.

Location.

Hills....................'........................................................

Plains. ............ ...............................................................

Average 

yield' (gallons pei 

minute.

24.4

20.6

8.7

18.8

Number of 

records.

18

27

25

9

TABLE 4. Relation of average yield of wells in various topographic locations to average 

yield of wells in any rock type and in any location.

[Yield in gallons per minnte.]

' Rock.

Schist..................

Other crystalline rocks . .

Location.

Hills............

Hills............

Hills............

Hills............

Relation of average yield of 

wells in any location to 

average yield of all wells in 

same kind of rock.

Average 

yield for 

location.

9.3 

10.3 

21.7 

26.5 

4.7 

10.0 

21.8 

10.1 

24.3 

24.7 

2.2 

42.5

Average 

yield for 

rock type.

17.4 

17.4 

17.4 

17.0 

17.0 

17.0 

17.0 

17.0 

17.0 

26.4 

26.4 

26.4

Difference.

- 8.1 

- 7.1 

+ 4.3 

+ 9.5 

-12.3 

- 7 

+ 4.8 

-6.9 

+ 7.3 

-11.7 

-24.2 

+ 16.1

Relation of average yield of 

wells in any location to 

average yield of all wells in 

same kind of location.

Average 

yield for 

location.

9.3 

10.3

21.7 

26.5 

4.7 

10 

21.8 

10.1 

24.3 

21.7 

2.2 

42.5

Average 

yield for 

all in 

similar 

location.

20.6 

8.7 

24.4 

. 20.6 

8.7 

24.4 

20.6 

8.7 

24.4 

20.6 

8.7 

24.4

Difference.

-11.3 

+ 1.6 

- 2.7 

+ 5.9 

- 4 

-14.4 

+ 1.2 

+ 1.4 

- .1 

+ 1.1 

- 6.5 

+ 18.1
102 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

TABLE 5. Relation of level at which water stands in wells in various locations to surface 

of rock which marks bottom of overlying drift.

Bock. Location.

fHills............. ...........

1 Valleys. ....................

IPlains............ ...........

(Hills........................

fHills........................

1 Valleys .....................

] Slopes. ...................... 

plains.... .......... ........

1 Hills........................

Valleys....................

Plains......................

Percentage of 

wells in which 

water level is 

below rock 

surface.

37

11

50

62.5

0

50

69

22

44 

0

71

0

60

33

Percentage of 

wells in which 

water level is 

above rock 

surface.

50

89

50 

50

37.5

100

33

21

78

36 

50

0

100

40

67

Percentage of 

wells in which 

water level is 

even with rock 

surface.

13

0

8 

0

0

0

17

10

0

20 

50

29

0

0

0

NOTE. A summary of the results for all wells may be found on page 133.

TABLE 6. Average depth and yield of wells in varying rock types.

Rock.

Schist (other than quartzPhyllite (slate)...........

Depth of surface 

material.

Feet.

20.6 

16.3

13.'7 

24.1 

32.5 

14.4

Number 

of 

records.

45 

69

23 

15 

3 

5

Depth in rock.

Feet.

100.5 

112.6

96.0 

138.5 

411.0 

80.2

Number 

of 

records.

45 

70

23 

15 

3 

5

Total depth.

Feet.

122.5 

131.4

109.7 

156.6 

443.5 

93.8

Number 

of 

records.

54 

73

23 

19 

3 

5

ield.

«t 

Gallons 

per 

minute.

13.0 

12.3

13.9 . 

33.0 

7.25 

Very poor.

Number 

of 

records.

35 

50

16 

13 

3 

5

TABLE 7. Average depth from surface to water level in the well.

Location.

Hills............................................................................

Slopes. . ............................ ..............................

Plains....................................... ...................................

Depth to 

water.

Feet. 

19

11

15

8

Number of 

records.

76

30

44

30

TABLE 8. Average depths, in feet, of surf ace material, of rock, and of the entire well for 

the records at hand, exclusive of wells more than 400 feet in depth and of wells known 

to be dry.

Location.

Hills ...................................................

Plains.... ..............................................

Average 

depth of 

surface 

material.

36

17

21

10

Average 

depth in 

rock.

104.5

94.0

79.4

74.0

Average 

total depth.

140.5

111.0

100.4

84.0

Number 

ofrecords.o

26

67

54

16

a Average depth of surface material based on only 122 records. 

NOTE. Average total depth of all these wells is 108.4 feet.
GROUND WATEK IN CEYSTALLINE EOCKS. 103

It is clearly shown in Table 1 that there is an increase in the 

average yield of wells with increase in depth to a certain point, beyond 

which the average yield tends to decrease, owing mainly to the larger 

proportionate number of the deep wells that prove to be failures. 

The table also indicates that most of the wells are between 30 and 

200 feet in depth. The wells in granite are evenly distributed over a 

considerable range in depth, but most of the wells in gneiss are 

shallow, 70 per cent being less than 100 feet deep. The wells in 

granodiorite whose records are available are mostly in the schistose 

area near Stamford, and the data indicate that in this rock good supplies of water are obtained at considerable depth.

Table 8 indicates that the impression of well drillers that wells 

obtain water at shallower depths on hills than in valleys is borne out 

by the facts, but that the greater part of the difference is due to the 

heavier deposits of surficial drift in the valleys. On the other hand, 

it is shown in Table 3 that the average yield of wells in valleys is 

somewhat greater than that of wells on hills. If there were any 

relation between the yield of wells and their topographic situation it 

would seem that wells located on slopes should give an average yield 

intermediate between that of the wells on hills and that of the wells 

in valleys. On the contrary, the wells on slopes average a yield less 

than half of that for either of the other locations and the wells on 

slopes are also the shallowest of the three groups.

Table 5 shows that the ground water in wells in granite has an 

occurrence differing from that in the other rock types, the position of 

the water level with reference to the rock surface being the reverse in 

wells on hills and slopes to that in the other rocks, though in the 

wells in valleys the same relation is shown by all rock types.
CHAPTER V. 

GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS.

INTRODUCTION.

The bed rock of Connecticut, as is shown on the map (fig. 11), 

consists of two main types, widely separated in character and age 

the pre-Triassic metamorphic crystalline rock and the Triassic sandstone, conglomerate, shale, and lava. In the sedimentary rocks and 

traps of the Triassic area the water occurs in four situations within 

the rocks themselves, in bedding planes, in joints, and along fault 

lines.

WATER WITHIN THE ROCKS.

CONDITIONS OF OCCURRENCE.

No rock is so dense as to exclude water entirely. However firm 

and compact it may appear to be, there are spaces between the individual grains and crystals, of capillary size and larger, which, though 

invisible, allow access and movement of water. Though it is true 

that all rocks possess a capacity to hold water, yet the amount of 

available space varies within wide limits, in accordance with the 

character of the rock. In the crystalline rocks, composed of closely 

interlocking crystals, there is small space for water, and the densest 

known granite (from Montello, Wis.) has an average porosity of only 

0.237 per cent, or about 1 part in 400. In sand the pores may constitute 30 to 40 per cent of the volume; in sandstone, 20 per cent or 

more. The sedimentary formations of Triassic age in Connecticut 

include sandstone, conglomerate, and shale, all of which have relatively large water capacity.

WATER IN SANDSTONE.

The prevailing sedimentary rock in Connecticut is sandstone, 

which varies in texture from coarse to fine and in color from choco- 

.late brown to reddish brown, with local green and buff tints. Commercially the rock is known as "brownstone," and the quarries of 

Portland, Long Meadow, and other places have furnished a great 

amount of it for building purposes. The large outcrops of sandstone 

in Connecticut are generally not homogeneous, presenting as a rule 

wide variation in grain, conformity, order of stratification, and relative amounts of the component strata. Overlapping lenses of sancl104
GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS. 105

stone, conglomerate, and shale, rather than uniform beds of sandstone, make up the formation. In one of the quarry pits at Portland four types of rock are sufficiently distinct to be separated for 

commercial purposes.

The Triassic sandstone of Connecticut consists of quartz, feldspar 

(in many localities kaolinized), biotite, muscovite, and garnet, with 

fragments of chlorite schist, mica schist, gneiss, and granite. The 

cement which holds the grains together and gives color to the rock is 

partly a film of iron oxide surrounding the grains and partly fine clay.

Sandstone in general has great water-holding capacity, and the 

Connecticut varieties form no exception. A sample from the Portland quarry which was dried*carefully and then immersed in water 

for three months was found to have increased in weight during that 

time from 150 to 154 pounds,0 an absorptive ratio of about onefortieth of the weight of the specimen examined. The amount of 

water absorbed was about 2 quarts for every cubic foot, equivalent 

to 88,502,857 barrels for a square mile of rock 200 feet deep. This 

is sufficient water to form a lake 1 mile in diameter and 50 feet deep.

In spite of its capacity for holding such enormous quantities of 

water, the exposed portions of the sandstone usually appear dry. 

In railroad cuts and on cliffs 

the water is not seen to ooze 

out of the rock nor to form a 

film over its surface. It is 

only in artificial openings, such 

as wells, that the water drips 

from the rock itself. This absence of water on the face 

of a natural rock outcrop does 

not indicate that the rock is 

not saturated at a short distance back of the face, for the

water within the rock would naturally seek a lower level of escape 

through some bedding plane or fracture nearer the base of the 

hill. In several localities springs issue from crevices immediately 

above which the rock is practically dry. In such localities the 

water table is depressed at the point of leakage. 6 (See fig. 15.) The 

depth to which saturated sandstone extends varies with the topographic location and character of the rock, but is in few places more 

than a few hundred feet. Wells are reported where the rock was so 

dry between depths of 200 and 300 feet that water had to be pumped 

into the hole to enable the drill to perform its work.

a Stone, vol. 9,1894, p. 20.

b Fuller, M. L., Water-Supply Paper TJ. S. Geol. Survey No. 110,1905, p. 98.

IMPERVIOUS BED

FIGUBE 15. Diagram illustrating depression of water 

surface at point of leakage in sandstone.
106 UNDERGROUND WATER RESOURCES OF CONNECTICUT. 

WATER IN CONGLOMERATE.

Interbedded with the sandstones are lenses and short layers of 

conglomerate, and at several localities, as in the vicinity of New 

Haven and elsewhere along the Triassic border, this rock occurs.in 

great abundance. The pebbles in the conglomerate average from 

1 to 5 inches in diameter, but reach extremes of more than 2 feet. 

Conglomerate is cemented gravel, and the pebbles of which the Triassic 

conglomerate of Connecticut is composed are crystals of quartz, 

feldspar, and mica, together with partly rounded fragments of schist, 

gneiss, porphyries, granite, and pegmatite. The pebbles, large and 

small, lie in a matrix of sandstone. .The cementing material and 

coloring matter are identical with those of the sandstones, except 

that there is perhaps a smaller amount of clay.

The conglomerate contains within itself abundant water, as its pore 

space is relatively large, but, like the sandstone, it seems to give up 

its water readily to joints and other large openings and to be relatively dry at great depths. The deep wells in the Connecticut 

Triassic area which have been failures the Northampton well, 3,700 

feet deep; the Westfield well, 1,100 feet; the Forestville well, 1,290 

feet; and the Winchester Arms Company well at New Haven, 4,000 

feet are in the conglomerate. The easterly dip of the conglomerate 

along the west side of the Triassic area suggests conditions favorable 

for flowing wells, especially as the upturned edges of the strata are in 

a position to receive the water from the Western Highlands and to 

carry it eastward into the ground. These favorable conditions are, 

however, offset by the lack of continuity in the rock strata due to 

the presence of joints and faults. (See pp. 133-135.)

WATER IN SHALES.

The shales of the Connecticut Valley, popularly called "slate," do 

not cover wide areas to the exclusion of other rocks, but occur as 

beds or lentils interstratified with the sandstones, conglomerates, and 

lavas which make up the Triassic of the State. Typical shales are 

layers of mud that have become consolidated by the addition of 

cementing material and by the pressure of overlying ro6k masses. 

The fragments of which they are composed are largely grains of 

quartz, feldspar, and mica, either fresh or partly disintegrated, and 

the layers into which a shale outcrop is divided are usually but a 

fraction of an inch thick.

Pure mud shales contain a large amount of water, but the pore 

spaces are so small that they retain it with great tenacity and wells 

sunk in unbroken shale beds of homogeneous structure remain as 

holes with moistened sides but with an amount of water insufficient 

for practical purposes. The Triassic shales, however, are not homo-
U. S. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 232 PLATE IV

A. VERTICAL AND HORIZONTAL JOINTS IN SANDSTONE.

B. VERTICAL AND HORIZONTAL JOiNTb IN TRAP.
GROUND WATER IN TEIASSIC SANDSTONES AND TRAPS. 107

geneous layers of compressed mud and silt, but thin beds of shale 

alternating with sandstone, and much rock which passes for shale 

or "slate" is in reality a very fine grained sandstone of large water 

capacity. Furthermore, the shale contains some small lenses of lime 

and gypsum, possibly also salt, which are readily dissolved and leave 

channels and pipes through which ground water may circulate with 

great freedom. The shales are furthermore broken by joints and 

faults of sufficient extent to permit the passage of water. These 

characteristics make the Triassic shales of scarcely less value than 

the sandstone as sources of water, although the quality of the water 

is usually inferior. The chief importance of clay shales, however, is 

not as a water carrier, but as a confining layer in the midst of more 

porous material which serves to collect and transmit the water, giving rise to springs and determining favorable locations for wells. 

(See p. 109.)

WATER IN TRAP.

There are two chief types of trap rocks in the Connecticut Valley 

extrusive volcanic rocks (basalt) and intrusive rocks (diabase) but 

considered in regard to their water-bearing capacity they may be 

treated as one. Except for the amygdaloid cavities in the lavas, 

filled with fresh or decomposed calcite, zeolites, etc., the traps are 

exceedingly dense, and the interlocked crystals of feldspar and pyroxene afford practically no access to surface waters. That ground 

water does not penetrate these rocks is clearly shown by the presence 

of unaltered anhydrite and bitumen at depths less than 30 feet from 

the surface. Moreover, the topographic form of the trap ridges prevents their absorption of surface waters. They project high above 

the surrounding plain and slope in two directions, and the rain that 

falls on them is hurried to the lowlands in streams. In fact, the lower 

slopes of the lava ridges furnish favorable catchment areas for surface 

waters, which are utilized by Hartford, New Britain, Meriden, and 

New Haven for city water supplies. Under the most favorable conditions the traps contain within themselves probably less than onehalf of 1 per cent of their weight of water, and therefore may be disregarded as water reservoirs. (See PL IV, B.}

WATER IN BEDDING PLANES.

CONDITIONS OE OCCURRENCE.

The sandstone, conglomerate, and shale of Connecticut, although 

differing markedly in texture, in extent and uniformity of bedding, 

and in structural relations, are alike in being water-laid deposits. 

They constitute a series of parallel strata separated by more or less 

definite bedding planes, whose location, extent, and character exert 

a predominant influence on the water supply of the State. If the
108 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

strata composing the Triassic were all of one type and homogeneous 

the ground water would be uniformly distributed, but owing to the 

different degrees of permeability possessed by the sandstone and shale 

the water tends to concentrate along definite horizons. For example, 

a bed of impervious shale overlain by sandstone allows water to accumulate in the upper strata. The water occupying the spaces between 

the sandstone grains will find it easier to move along the bedding 

plane than to penetrate the shale, and if the plane is exposed on a 

hillside or in an artificial opening a stream or seepage of water will 

likely be developed. (See fig. 5.) Shale is the most impervious rock 

in the sedimentary series and sandstone the most pervious, and together they form the best reservoirs, but water will occupy the bedding plane between sandstone and lava, or between sandstone and 

conglomerate, or between two beds of the same strata. The bedding 

planes are not usually actual cavities visible to the eye, but rather 

planes of parting through which water moves by capillarity. In some 

places, however, the solvent action of water operating for thousands 

of years has widened the cracks to a fraction of an inch, and in a very 

few localities definite stream channels several inches in height have 

been developed through which water pours as small-sized rills.

That water occupies these bedding planes in large amount is abundantly shown by direct observation and by the experience of well 

drillers. In one of the Portland quarries, where pits 200 feet in depth 

have been opened "water everywhere emerges from along the bedding 

planes, especially along the shaly partings, where, dripping down, it 

darkens the quarry walls over large surfaces." 0 In 1906 an exposed 

rock wall 75 feet in height in this quarry showed water entering from 

the bedding planes in large amounts, but none coming from the joints 

or oozing from the rock surface. In dozens of springs within the 

sandstone area the water issues from the contact between strata of 

varying texture and composition.

The experience of well drillers leads to the same conclusion. C. L. 

Wright, of Augurville, who has sunk many wells in the sandstone, 

finds that the water eomes from "flat seams " that is, bedding planes 

at the "juncture of firmer rocks overlain by loose-textured rocks" 

and that water frequently passes from these planes as a "sheet extending entirely across the drill hole." A. A. Murray, of Middletown, 

reports that the largest amount of water "is to be encountered in hard 

rock directly at its contact with shale." In the vicinity of Hartford, 

according to C. L. Grant, the "usual water horizon is in the sandstone 

directly above trie shale."

That water circulates freely along definite bedding planes is shown 

by the manner in which wells that are located in proximity tend to 

influence one another. For example, five wells of the Electric Light

a Stone; vol. 9,1898, pp. 43-43.
GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS, 109

Company in Hartford, sunk in sandstone and shale to a depth of 200 

to 225 feet and situated 40 to 50 feet apart, are all affected whenwater is pumped from any one, apparently because they draw their 

water from the same bedding plane. Other interesting evidence of 

the presence of water in bedding planes and its movements along these 

planes is furnished by two wells at the sanitarium 2J miles northwest 

of Wallingford. One of the wells became contaminated by gasoline 

from a buried tank, and shortly afterward the other, 225 feet distant 

in the direction of the slope of the rock, became contaminated also. 

The polluted water had apparently traveled down the tilted bedding 

plane between sandstone layers.

Another proof of the circulation of water along bedding planes is 

found in the fact that the rock bounding these planes is decomposed 

by the action of chemicals carried by subterranean waters. In quarries and railroad cuts where these bedding planes are exposed they 

usually appear as lines or zones of discolored rock, but in many places 

there is a distinct layer of leached and disintegrated material that has 

formed in place by slowly moving ground water charged with carbon 

dioxide and other chemical reagents.

BLACK SHALE.

Probably the most impervious rock within the Triassic area is the 

black bituminous shale which occurs as a member of the "Posterior" 

sandstones. (See p. 39.) In the vicinity of Hartford this shale has 

been penetrated by wells at a number of localities and at different 

depths, and it rarely fails to define a water horizon of great importance. The logs of wells shown in figures 16 and 17 were furnished 

mainly by C. L. Grant and demonstrate two interesting facts (1) 

that the water-bearing strata may be shale, as in the Newington, 

Allyn House, and Goodwin Park wells; or sandstone, as in the Bloomfield wells; or conglomerate, as in the Windsor street well; and (2) 

that the typical posterior black shale, unmixed with sandy layers, is 

a water-confining bed of exceptional impermeability, even where only 

10 feet in thickness. The well of F. C. Dininy obtains its principal 

water supply at 256 feet below the surface and little water was encountered at a greater depth. *

WATER IN JOINTS.

VERTICAL AND HORIZONTAL JOINTS.

As explained on pages 37-38, all rocks are traversed at relatively 

short intervals by cracks or seams which serve to mark the rock 

surface into polygons and break it up into blocks of various sizes. 

These are the joints in rocks, and their presence and distribution are 

important factors bearing on the water supply of Connecticut.
110 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

Hard pan ........ 4

Red shale........ 42

Black shale...... 3

Red shale........ 146

Conglomerate... 61

Black shale...... 10

Red shale........ 118

Black shale...... 23

Bed shale .. ..... 117

1.

|p~ o.o

o o f _O 

'O.°o0.C 

12::^ 256 Water.

is 381

Red shale...................... 5

Sandstone and grit........... 9

Black shale with clay......... 31

Red sandstone.. ..............

Black shale and sandstone ...

Black shale.

Black and clay shale.......... 4

Black shale.................... g

Brown-black and clay shale.. 8 

Sandstone, black shale, and 

blue clay shale.............. 8

Veryblackcarbonaceousshale 1

Soil.

Mud conglomerate............ 186

Bed shale.

Black shale.................... 15

Red shale... 

Black shale.

Red shale...

2.

. 3.

.

o* o . To-'-.'o

72 

76 

Si 

92

100

101 Water.

t j - V6i 'i W*A

FIGURE 16. Well logs shoirfiig'influence of Triassic black shale in determining water'horizons. I, Well of 

F. C. Dininy, Windsor streQt.tHarttord; water stands at 95,feet when well is pumped; yields 40 gallons a 

minute at 150 feet. 2, Well of H. C. Douglass, Bloomfleld; flows 2 feet above surface; data furnished by 

owner. 3, Allyn House well, Hartford,
GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS. Ill

The joints in Triassip sandstone, conglomerate, and shale intersect 

at various angles, both in the vertical and in the horizontal plane, 

and many of the blocks which they bound are wedges of large or 

small size. Numerous measurements of the inclination of joint 

planes show that they stand commonly at high angles approaching 

the vertical. In the Fairhaven tunnel the prominent joints dip 

between 65° and 86° S. In the railroad cut north of Yalesville and 

in several other localities the dip of the main joints is less than 10° 

from the vertical. Approximately three-fourths of the conspicuous 

joint planes noticed at sixteen localities in Triassic sedimentary

Soft red 

sandstone 48

Hard red 

sandstone 18

Blue slaty 

shale ... 30

Sandstone 17

Blue shale 22

Red shale. 35

Hard black 

shale ... 17

Red shale. 44

Clay and 

hardpan 38

Shale..... 6

C o nglomerate ... 40

135

142

Shale and 

sands tone 88

Shale..... 33

Bed shale. 74

Black 

shale ... 35

164 Water. 

155

Redshale. 43

183

187 Main

Water. 

43

185

800

FIGURE 17. Well logs showing influence of Triassic black shale in determining water horizons. 1, Flowing 

well at Goodwin Park, Hartford. 2, Well of L. A. Storrs, Bloomfleld. 3, Well of Dr. A. B. Johnson, 

Newington; yields 40 gallons a minute.

rocks are between 70° and 90° from the horizontal. There are, 

however, numerous fractures which are nearly or quite parallel to 

the planes of stratification and which serve to break the rock into 

still more irregular and indeterminate fragments. - These horizontal joints are in many places approximately parallel to the surface of the ground, and where they cross the bedding planes it is 

usually at an angle of less than 25°.

Joints, both vertical and horizontal, are more common and more 

conspicuous and intersect at a larger number of angles in conglomerate and coarse sandstone than in shales. In fact, large regular blocks 

of conglomerate are quarried in very few places within the State.
112 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

In the sandstone quarries the joints are fairly regular and evenly 

spaced. In the long exposure of shaly sandstone in the gorge at 

South Meriden vertical joints are rare. Near Mill Rock joints in 

fine sandstone start, branch, and die out within a few inches, and in 

a number of localities joints traversing sandstone and conglomerate 

stop abruptly on reaching a stratum of shale. (See below.)

DIRECTION AND CONTINUITY OF JOINTING.

In the Portland quarry the prominent joints run N. 50° E., N. 

60° E., N. 75°-85° E., and N. 20° W.; in the vicinity of New Haven 

the chief joints extend east and west, N. 70°-80° W., N. 20° W., N. 

15°-20° E., and N. 50° E.; at West Granby, N. 80° W., N. 35° W., 

N. 10° E., and N. 20° E.; at West Cheshire, N. 80° W., N. 50°-60° 

W., N. 30° W., N. 10° E., and N. 55°-60° E. In the Pomperaug 

Valley Hobbs 0 found four major directions of jointing N. 34° W., 

N. 5° W., N. 15° E., and N. 54° E. Although these uniform joint 

directions indicate some cause operating throughout the Triassic 

areas, there are many local variations, and in each region prominent 

cracks occur which do not correspond with the more common joints. 

For practical purposes each locality must be studied separately.

Some of the more prominent joint planes have been traced on the 

surface for several hundred feet and from the top to the bottom of 

the deepest quarry and railroad cuts. A few doubtless extend parallel to fault lines for some thousands of feet. Most of the joints 

observed, however, appear as open cracks for distances rarely exceeding 50 feet, though they may extend for great distances, both vertically and horizontally, as invisible parting planes.

^

SPACING OF JOINTS.

In the outcrops of sedimentary rock examined there was found 

great irregularity in the number and distribution of joints. In 

places the joints are 50 to 60 feet apart; elsewhere ten to twenty joints 

occupy 50 feet of wall space. In most large outcrops there are zones 

along which joints are crowded at intervals of less than an inch, and 

on weathered surfaces and in cuts where blasting has been carried 

on the rock is shattered into fragments a few inches in thickness by 

a multitude of intersecting joints. Outcrops of red and black shale 

occur in which the horizontal joints have separated the rock into 

chips or flakes that could be removed with a shovel. It is evident that in such rock ground water would circulate freely and be 

stored in large quantities. In the Portland quarries the main sets 

of vertical joints are 30 feet or more apart; at the north end they are 

35 to 100 feet apart; and nowhere in the quarry were joints of the

o Hobbs, W. H., Twenty-first Ann. Kept. U. S. Geol. Survey, pt. 3,1901, p. 100.
GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS. 113

same series observed nearer than 7 feet from each other. In the 

railroad tunnel at Fairhaven the larger joints are about 25 feet apart 

and converge at low acute angles and branch out. At Pine Rock 

and West Rock the joints of all kinds average about five to a linear 

yard. The spacing of joints and their angle of inclination are the 

factors which determine the number contributory to a well.

Both vertical and horizontal joints are wider, more numerous, 

and more closely spaced near the surface than farther down. In one 

quarry observed by the writer the upper 30 feet of wall had nearly 

twice as many horizontal joints as the second 30 feet. The effect 

of joints is to greatly favor the absorption of water, but this must 

be a surface phenomenon, as the joints die out with increasing depth. 

In Connecticut large open joints are probably rare at depths exceeding 200 feet.

OPENING OF JOINTS.

Some joints at the earth's surface and probably all joints at considerable depths are tightly closed and are more nearly planes along 

which the rock might be broken than open cracks. Many joints, 

however, are a fraction of an inch wide, some are 1 inch to 2 inches 

wide, and in the Blakeslee quarry horizontal joint zones 3 to 4 inches 

wide are found. One crack in this quarry which is 1\ inches in 

width at the top was so narrow at the bottom that a sheet of note 

paper could not be inserted. Many joints exposed in quarry walls 

are filled with decomposed rock through their extent, and experience in well drilling proves that decomposition extends to considerable distances and serves to enlarge cracks to an important degree. 

(See pp. 73-74.) Where two joints intersect or where one crosses a 

bedding plane a channel may be developed by removing the disintegrated rock which forms the boundary planes. (See fig. 18.) In 

one of the Portland quarries the water enters in good-sized streams 

from vertical joints to an amount estimated at 250,000 gallons 

daily. Such freedom of circulation would account for the waterlaid sand found in joints at Hartford 20 feet below the surface. 

Numerous small joints, however, furnish more abundant and uniform water supply than a few large open fractures.

JOINTS IN TRAP.

The direction, continuity, and inclination of cracks in the trap 

of the Triassic area are essentially the same as in sandstone. Exposures of trap rock are invariably characterized by well-developed 

vertical joints intersecting one another in all directions in vertical 

planes and dividing the rock into a series of polygonal blocks. This 

type of jointing undoubtedly is more conspicuous in exposures than 

it would be in unweathered ledges, yet the structure is developed in 

463 IBR 232 09 8
114 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

deeply buried rock and occasions trouble in drilling, owing to the 

breaking off of angular blocks that wedge the tools.

The opening of joints in trap and their value as reservoirs are 

practically the same as in the denser crystalline rocks described in 

Chapter IV (pp. 54-103).

WATER ALONG FAULT LINES.

Faults in rock are joints or cracks along which the strata have 

moved up or down or sidewise. The amount of displacement may 

be a fraction of an inch or thousands of feet, but as a rule there is a 

complete break in the continuity of the strata and a more or less 

open crack to mark the line of rupture. Few faults are single cleancut breaks; more commonly they consist of a number of breaks that

Fault zone 

FIGTTBE 18. Sketch showing fault zones in sandstone.

Fault zone

result in shattering the rock along a line some feet in width, forming 

a zone of material arranged as a confused mosaic of loose or 

cemented fragments.

The structure of fault zones is favorable for the absorption of 

large quantities of ground water, which may be readily recovered. 

(See fig. 18.) Many springs in Oregon, the hot springs of the southern 

Appalachians, Saratoga Springs, etc., are located along faults, and 

the character of their waters is due to the great depths from which 

they come. The relation of springs to fault lines is a well-known 

phenomenon in Connecticut and some striking instances have been 

described by W. H. Hobbs.0 At one place in the Pomperaug Valley 

eight springs occur within a distance of 60 rods, all located on a single

a Twenty-first Ann. Kept. U. S. Geol. Survey, pt. 3,1901, pp. 91-93.
. GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS. 115

fault line. Near South Britain a number of springs are located at 

the intersection of two or more fault lines.a Where fault lines are 

exposed in cuts and quarries the circulation of water in them is 

shown by actual seepage, by growth of plants, and by a zone of 

decomposed rock, formed by the solvent and oxidizing power of the 

ground water carrying carbon dioxide, etc., in solution. The relation of faults to water supply is well illustrated in the Middlesex 

quarry. Here the principal water carrier is an oblique fault zone 6 

inches to 1 foot wide, which not only absorbs much water from the 

earth's surface but is also the main artery receiving supplies from 

bedding planes one-fourth to one-half inch wide. This fault contains probably 15 per cent of open space available for water storage. 

Examples of wells located on faults are those of the Hartford Light 

and Power Company and of Armour & Co. at Hartford. The wells 

at the New York, New Haven and Hartford power house and 

the Berlin Brick Company and the Yale Brick Company's works, 

Berlin Junction, and at Hotel Russwin, New Britain, are advantageously located near fault zones.

RECORDS OF WELLS IN TRIASSIC SANDSTONES, CONGLOMERATES, AND SHALES.

The records of wells on the following pages have been selected to 

show the conditions controlling the recovery of ground water in the 

Triassic sediments of Connecticut.

a Water-Supply Paper U. S. Geol. Survey No. 67,1902, p. 80.
Records of wells in sandstone and other Triassic rocks o

13

i

*i

2

3

4

S

6

7

8

9

10

11

*12

13

14

IS

Ifi

17

If

19

20

Town.

Berlin.........

.....do........

.....do........

.....do........

.....do........

Bloomfleld....

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

East Hartford.

.....do........

.....do........

Village.

ter.

.....do........

.....do........

Owner.

Mrs. J. B. Hadsell.

G. H. Sage......

J. B. Smith......

F. L. Wilcox....

F. S. Hall.......

and Feed Co.

Manufacturing 

Co.

Albert Eich.....

J. M. Mohrs.....

P. Donohue. ....

Topographic 

position.

PlainHill...

Hill...

...do...

SlopeValley.

bed. 

Flat...

...do...

...do 

Depth to rock.

Ft. 

70

75

60

4

5

?,?,

35

11

1?

1?

S

IS

IS

17

30

Depth in rock.

Ft. 

30

75

55

47

96

14

7

ISO

313

?4

S3

40

33

34

46

Depth of well.

Ft. 

100

224

150

201

220

115

51

101

36

42

191

325

36

SS

150

58

980?

48

51

76

Depth to princi- pal source.

Ft.

75

148

220

28

42

33

f 35 

J 4-0

I 85 

146

43

Depth at whichwater stands.

Ft. 

23

46

50

50

50

20

26

+ 2

22

14

17

35

2

I S

19

8

15

15

31

Variation 

of water 

level.

lowers.

ered at 30 

gallons.

lowers 

and lower 

in summer.

& 

S

SB 

ft£

2 "3

>H

Gal

Goo

+
?,1

w,

23

*?4

2S

*?,6

?,7

28

29

30

si

32

33

34

35

36

37

*38

40

41

42

43

44

45

46

*47

4R

49

50

51

52

53

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do.........

.....do........

.....do........

.....do........

.....do........

Glastonbury..

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

Point.

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

ville. 

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

Co.

C. M.~ Finch.....

Co.

J. W. Copley....

B.C. Alien......

E. King.. .......

ley Brewing Co.

Mrs. M. Fox.....

C. N. Carter.....

H. D. Clark.....

F. S. Brockett...

fPhelps Montl gomery. 

W. W. Terrell...

I. V. Cook.......

Hill...

Slope..

Hill . . .

Flat...

Flat...

Hill . . .

...do...

...do...

Plain..

...do...

Flat...

...do...

Flat...

...do...

Hill...

...do...

...do...

...do...

Valley.

Plain. .

Plain..

...doPlain..

J

7

"J

60

60

135

17

9

87

10

40

CO

15

4

90

1?

17

38

15

40

15

17

25

150*

28

1?

35

3

8

99J

48

54

2fi

135

385

209

30

31

67

58

26

44

15

40

50

67

23

33

31

3?

35

741

QO

58

7

35

398

100

55

714

86

310

270

402

218

117

t\7

41

107

48

105

52

67

105

38

73

46

40

60

225

60

70

42

80

43

116

<;n

41

45,67

210-225

50

37

f 33

} fin

1 78

80

28

15

22

48

80

10

43

47

11

10

20

28

5

5

15

7

22

13

23

36

12

19

10

30

/Flows,

\2+. 

14

28

I 18

I 

15

30

lowers 8 

feet.

feet In dry 

weather.

fP u m p s

I 6 feet.

Pumping

{ 26 feet.

with wet 

and dry 

season. 

Constant . .

Ve

1

Goo

} 

} 

Additional details concerning wells mark ed * are 
Records of wells in sandstone and other Triassic rocks of Con

0

fc

64

55

56

l\7

fiS

59

60

61

62

63

*64

65

66

67

68

69

Town.

.....do........

.....do. .......

.....do........

.....do........

.....do........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do .. .....

.....do........

Village.

.....do........

.....do.........

.....do.........

.....do.........

.....do.........

Owner.

C. L. Wright....

B. A.-Davis.....

F. D. Grave.....

H. R. Stadtmiller.

Country Club. 

F. D. Putnam...

ber Works Co. 

D. F. Burns.....

Y. M. C. A......

Topographic 

position.

...do...

Slope..

Ridge.

Hill...

...do...

Valley

Valley

Slope..

Foot of

hill.

Depth to rock.

Ft.

8

4

0

0

8

12

190

40

5?

58

Depth in rock.

Ft.

38

119

140

43

85

8?

153

160

223

148

142

Depth of well.

Ft. 

55

46

140

123

140

Kf\

85

Qfl

196

165

1,250

350

263

200

200

251

Depth to princi- pal source.

Ft. 

40

28

130

qc

40

ion

164

+200

175

166

Depth at whichwater stands.

Ft. 

15

12

17

20

34

3

22

35

30

20

18-

50

9+.

+ 31.

Variation 

of water 

level.

with wet 

and dry 

season.

lowers 20 

feet. 

5

Pumping

lowers to 

40 feet.

feet with 

dry and 

wet season.

lowers.

Yield per minut

Gal

+ 

+

1J.
70

71

7?

73

*74

75

76

77

78

*79

*sn

*81

*8H

8?

83

84

*85 

8fi

87

88

89

nn

*Q1

Q9

QO

Q4

95

96

97

.....do........

.....do.........

.....do.........

.....do.........

.....do.........

.....do..... ...

.....do.........

.....do.........

.....do........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do......... 

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

Chester. 

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

Chester. 

.....do.........

nail Co.

Co.

and Power Co.

Brewing Co.

Brewing Co.

W. C. Wade.....

Cheney Bros.....

.....do...........

.....do...........

.....do...........

American Writing Paper Co.

T. P. Lyon......

ing Co.

Co.

Co.

Hill...

...do...

...do...

PlainHill. . .

Flat...

...do...

...do...

Fiat...

Valley

Slope. .

Plain..

...do...

150

1?

15

n

3?

W,

33

1?

20

12 

20

20

20

20

19

1fi

30

100

55

238

26

430

143

218

244

113

47

445 

205

105

55

81

87

46

74

136

205

206

250

41

430

175

240

620

462

420

500

277

125

67

457 

225

125

75

75

100

300

103

100

76

279

qnn

300

69

igo

400

35

70

0. 

86

52

15

12

25

1

15

12

13

21

Flows 

15+.

Flow.

20

6

18

0

Constant ..

Fl

Fl

For 2 feet 6 inches. 6 8 inches for 385 feet; 6 inches for 75 feet. 
Records of wells in sandstone and other Triassic rocks of Conn

o

fc

98

99

*100

*101

102

*103

104

105

106

107

108

109

110

111

112

*113

114

115

*116

Town.

.....do.........

.....do.........

.....do.........

.....do.........

Middlefield....

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

.....do.........

New Britain...

.....do........

.....do. .......

Village.

Meriden

.....do.........

.....do.........

New Britain...

Owner.

J. G. Schwinkjr.

Edward Miller &

Co.

ver Co.

Fixture Co. 

G. W. Durkee...

O.K. Miller.....

Hospital for Insane.

ber Co. 

Portland Silk Co.

facturing Co.

Son Co. 

Wilcox, Crittenden & Co.

& Clark. 

Hotel Russwin..

Topographic 

posiSlope. .

Flat...

Hill...

Plain. .

Hill...

Slope. .

Plain..

bed.

plain.

Slope..

...do...

Hill...

W

h torock.

P.

Q>

ft

Ft.-

100

50

70

g

40

70

dO

50

on

oc

50

40

15

40

h inrock.

§< 

ft

Ft..

460

255

15

qon

70

1381

156

71

120

qc

200

o co

785

?m

h ofwell.

& 

ft

Ft. 

80

102

(a)

560

305

85

110

2084

196

121

150

70

250

292

800

75

242

152

h toprincisource.

&a 

ft

Ft.

102

80

70

190

130

120

70

240

40

47

100

h atwhich 

er stands.

ft^

CP if

ft *

Ft. 

15

19

40

60

OK

2+.

3+.

Ofi

10

45

12-25

15

14

9

Variation 

of water 

level.

lowers 12 

feet.

lowers.

lowers.

lowers 30 

feet.

lowers....

'a 

s

s>

£H

Gall

Goo

(2)

Sma

Larg

Larg
117

118

*119

120

121

122

124

125

*126

"127

198

129

ion

1^1

132

1 ^3

134

135

136 107

138

139

140

141

142

143

144

145

146

147

NPW TTavpn

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

ford. 

.....do........

.....do.:......

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

,

Elm Hill......

.....do........

.....do........

.....do........

Clintonville....

Dairy Co.

ber Co.

peating Arms 

Co.

H. B.Ives.......

St. Francis Orphan Asylum.

W P T*1aVo

G.H. Gill........

matic Machine 

Co.

and Steel Co.

Manufacturing 

Co.

Mrs. T.H. Smith.

.....do..........

M. N. Wooding..

H. R. Smith.....

Slope..

Flat...

Plain. .

...do...

Hill...

SlopeHill...

...do...

...do...

Slope..

Plain..

Hill...

Hill...

0

6

26

6

3

12

264

119

32

8

70

1

20

20

0

0

4

30

15

46

1

101

91

59

?,36

147

90

308

53

406

168

203

123

57

99

44

62

14f>

.50

.50

59

1.5

24

1 Wl

160

4,000

101

97

85

242

150

102

572

42

525

200

203

121

127

75

 50

100

100

GA

62

140

50

54

96

89

30

75

70

140

4

1

Q<;

80

17

23

98

20

44

70

79

24

50

130

20

12

3

25

16

10

10

25

20

48

13

(«)

(d)

18

18

50

30

10

70

10

10

10

does not 

lower.

season.

lowers.

3

3

4

Go

Go

o5 wells, 250 feet. & Swampy ground. Flows in wet season. d Var
Records of wells in sandstone and other Triassic rocks of Con

1

148

149

150

151

152

153

1 U

155

156

157

158

159

160

161

162

*163

164

*165

*166

167

168

169

170

171

172

173

174

175

176

Town.

Plainville.....

Rocky Hill....

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

South Windsor. 

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

Village.

.....do........

.....do...'.....

.....do........

.....do........

.....do........

.....do:.......

.....do........

Milldale.......

.....do........

WestSuffleld..

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

Owner.

I. L. Stiles & Son

Brick Co.

\V. E. Pratt.....

School.

ufacturingCo.

C. Doothy. ......

W. Billings......

M. S. &C. T. Co.

B. F. Niehols....

Co. 

.....do..........

S.A.Kent......

J. Noble.........

W. Noble.. ......

W. II. Hastings..

Topographic 

position.

Flat. . .

Hill...

Hill . . .

...do..

Flat. . .

...do..

...do..

Hill...

...do..

Flat...

Hill...

Flat...

...do..

Valley.-

Flat...

Slope..

Hill...

...do..

...do..

...do..

...do..

Flat...

...do..

...do..

...do..

...do..

...do..

...do..

Depth to rock.

Ft. 

50

6

6

52

60

83

55

20

53

8?

13

2

84

60

67

67

6

OK

90

15

5

8

20

3

50

135

Depth in rock.

Ft. 

70

45

46

18

2fi

11

15

13

15

12

29

78

34

20

163

170

39

75

169

60

120

123

80

59

50

50

Depth of well.

Ft. 

120

51

52

56

212

70

86

94

70

33

78

94

42

80

200

118

80

230

237

45

100

259

75

125

131

. 100

62

100

185

Depth to princi- ctpal source.

Ft.

54+J

150

35

80

230

237

Depth at which water stands.

Ft. 

30

40

28

87

30

20

20

37

10

15

30

18

24

20

30

36

70

80

35

OR

18

12

17

24

24

24

20

Flows.

Variation 

of water 

level.

season.

&

a 

l

2 "3

JH

Ga
177

17ft

179

180

181

183

183

184

IDE

186

187

*188

IfcQ

*ioft

*i9i

1Q9

193

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

Windsor

Locks.

.....do........

Wilson S t a -

tion.

Heights.

G. D.Hall......

CityofMeriden..

Whitlock Coil

Pipe Co.

W. E. Howe.....

C, L. Grant, C. I.

Alien. 

.L. Grant, E.S.

Goodrich. 

Wm.L.Bidwell.

H. J. Fisk.......

Co.

Bros. 

Dr.H.J. Fisk....

J. O. R. Sheridan.

...do..

Plain..

Hill...

Small

hill.

Hill...

Hill...

...do..

Knoll.

Hill...

Hill...

84

55

fiOW

in

70

133

90

81

4,'i

137W

14?

61*

?,fi3

110

165

67

105

100

197

40

200

62

152

192

82

131J

135

386

113

135

200

80

30

200

135

13

80

30

25

30

i >\

85

62

26

4fi

40

30

pumping 

to 112 feet.

lowers.

lowers 5 

feet.

Cw
124 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

NOTES.o

1. Passed through 20 feet of gravel, 25 feet of quicksand, 25 feet of gravel and 

hardpan, and 30 feet of red shale, in which the water was obtained. The water comes 

in slowly and carries fine sediment.

12. A little water was obtained at a depth of 50 feet and the water rose within 12 

feet of the surface and remained at this level until a large supply was struck at a 

depth of 325 feet, when the water level lowered to 35 feet below the surface.

24. Passed through 17J feet of soil and through 54 feet of trap ending in a hard red 

rock, probably sandstone. The source of the water is at the contact between the trap 

and the sandstone.

26. This well was drilled through sandstone into trap rock and the water enters 

above the trap.

38. This well is 52 feet deep and 6 inches in diameter, 40 feet of its depth being in 

the rock. The water rises within 7 feet of the top, a good many feet above the level 

of Connecticut River, which is only a stone's throw away. The pump raises 31 

gallons a minute, which lowers the well 8 feet, but no farther. The water is moderately hard, has been used in boilers, and keeps a uniform temperature of 51° F. the 

year round.

47. Soil and sand, 20 feet; blue clay, hard and dry, 30 feet; clay and red quicksand, 10 feet; fine red quicksand, very shifting and hard packed, with a thin layer 

of saturated gravel at 118 feet from the surface, 60 feet; quicksand, 30 feet; gravel, 

8 inches; sandstone, varying in hardness at different depths, 74^ feet. The water stood 

at 8 feet below the surface in the first soil and sand stratum but dropped to 30 feet 

below the surface after the 30-foot layer of clay was penetrated.

64. This well was drilled in 1863 by Col. Samuel Colt and flowed until 1898, when 

a well was drilled 1,000 feet farther north and the Colt well stopped flowing the next 

day.

74. This well was drilled by C. L. Grant, who furnished the following data: Depth, 

250 feet; diameter, 8 inches. The well is in rock and flows. Elisha Gregory, a well 

driller of New York City, states in his "Torpedo circular" that the well was torpedoed 

by him at a later date and that as a result the yield was increased from 15 to 35 gallons 

a minute. It is reported that the quality of the water was injured by the process. 

Inquiry at the office of the company shows that at last accounts the water was not 

used for anything, so heavily is it charged with mineral matter. For analysis see 

table on page 177.

79. The 620-foot well of this company gives a more copious supply of water in rainy 

than in dry weather. The water contains too much calcium sulphate for boilers but 

is used for condensers. This well is said to have diminished the yields of four wells, 

each about 200 feet in depth, sunk for the same company.

80. It is stated that 400 gallons a minute have been pumped from this well without 

making any apparent impression on the water level. The well is 462 feet deep.

81. Depth, 420 feet. The water flows 1 inch over the top of the pipe when allowed 

to stand, which brings the water level above a large part of the neighboring land. 

The ordinary yield is 150 gallons a minute, the well being pumped continuously.

f81J. Depth, 500 feet; diameter, 8 inches. The water rises to the surf ace of the engineroom floor, and is pumped at the rate of 75 gallons a minute. The well is drilled in 

the "Upper" sandstones, but unquestionably pierces the "Posterior" trap sheet, 

which outcrops at no great distance to the west.

85. The water in this 457-foot well will rise 15 feet above the top and yield 205 gallons a minute at the surface. Pumping 600 gallons a minute for ten hours lowered the 

water level to 12 feet below the surface, where it remained constant.

a Descriptions of wells marked " t" are taken from Water-Supply Paper 110.
GBOUND WATEE IN TEIASSIC SANDSTONES AND TEAPS. 125

 jDl. Depth, 300 feet; diameter, 4 (?) inches. The water flows over the top of the 

pipe at a rate of probably 10 to 12 gallons a minute. The water is hard and is used 

for drinking purposes only. The well lies entirely in the rock, which, in the stream 

near by, is seen to be rather loose in texture and to be filled with fragments of the 

crystalline rocks of the neighboring eastern highland.

flOO. There are on the premises of this company five artesian wells, all 8 inches in 

diameter, from 250 to 300 feet deep, and bored into red sandstone, which at this 

place lies from 6 to 10 feet below the surface of the ground. The yield was measured 

when they were first bored, and varied in the different wells from 10 to 80 gallons a 

minute. The supply thus measured was obtained by means of an ordinary suction 

pump, which, operated at the rate named, lowered the water about 25 feet below the 

surface as low as it could be pumped with that form of apparatus. A few years ago 

a system that works by compressed air and forces the water from depths of 70 to 90 

feet was installed. This apparatus gave a very greatly increased output, which now 

supplies all the needs of the company. The water from these wells is all discharged 

into one large cistern, from which it is circulated through the factory. It is not easy 

to determine exactly the amount of water used, but it is estimated as between 75,000 

and 100,000 gallons a day of ten hours. A much larger quantity than this could be 

obtained if needed. The water is satisfactory for manufacturing purposes except for 

use in boilers.

101. A well 560 feet deep, penetrating 9 feet of soil, 18 inches of gravel, 90 feet of 

quicksand, and 459J feet of rock.

103. Drilled through 24 feet of clay, 20 feet of sand, 8 feet of clay, 50 feet of sandstone.

113. Depth, 500 feet. At a depth of 40 feet in sandy shale the well gave a small 

flow and drained an old dug well, 25 feet deep, in similar material. The well passed 

through about 300 feet of sandstone above bluish sandy shale and through a soft carbonaceous shale at about 400 feet. The well then passed through conglomerate and 

ended in blue clay shale. No water was struck below 40 feet and the flow ceased after 

a charge of nitroglycerine was fired in the well.

fl!6. Depth, 152 feet; depth of water when lowest, 130 feet, but if the well is a 

allowed to stand the water flows at the level of the engine-room floor, which is 10 feet 

below grade. The ordinary consumption is fully 10,000 gallons a day. The water 

can be used for all purposes. The well penetrated 140 feet of sandstone, etc., without 

finding enough water to keep the drill wet, but at that depth the drill became jammed 

in what appeared to be a crack about 2 inches wide, and an ingress of water followed 

the loosening of the drill. The apparent breadth of the crack may in reality be due 

rather to the presence of soft, decomposed rock along the joint plane than to an actual 

opening of the size indicated.

119. Drilled by the company in 1893, but no water was obtained except from 

surface seepage. It is 4,000 feet deep.

126. Depth, 572 feet. Penetrated 264 feet of quicksand and clay, the clay occurring mainly in small layers but with one 25-foot stratum above the rock.

163. Passed through 6 feet of loam, 76 feet of* sand, 2 feet of gravel, and 34 feet of 

sandstone.

f!65 and 166. Town water supply of Suffield, owned by Paulus Fuller. No. 165 

is 230 feet deep and has a diameter of 6 inches; No. 166 is 240 feet deep and has a 

diameter of 8 inches. The two wells together pump at the rate of 300 gallons a minute into a standpipe containing 293,000 gallons. The water rises within about 60 

feet of the surface and is rather highly mineralized. It can be used in boilers, however, but gives some scale. The wells enter rock about 10 feet below the surface.

188. Depth, 13tlJ feet. Passed through 70 feet of soil, consisting of light sandy 

soil, light gravel, coarse gravel, and hardpan, and penetrated 61J feet of soft red
126 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

sandstone. The water naturally stands at 26 feet below the surface, and on being 

pumped out to a depth of 75 feet gave the following flows, as recorded by Mr. Bidwell:

Depth 

(feet).

75

64

52J

48

Water 

rose 

(feet).

5

\ 3.5

\ 11.5

I 18.5

4.5

2.5

Time 

(hours).

1

1

1

2f

|

1

Feet per 

hour.

20

14

11.5

6.7

9

2.5

f!90. Depth, 386 feet; depth of water, 326 feet; diameter, 6 inches. The pump 

yields 30 gallons a minute, which lowers the water 5 feet. The well passed through 

sand, 17 feet; clay, 56 feet; hard red gravel, 50 feet; the remainder in sandstone with 

the exception of two layers of "slate." Four analyses of the water have been made, 

according to which it ranges from moderately hard to excessively hard. It would 

seem that the water is free from organic impurities, but shows sulphate of lime to 

the extent of 590 parts to the million. It is extremely hard to the soap test. When 

first drawn the water is said to give off a strong odor of hydrogen sulphide.

f!91. Depth, 113 feet; diameter, 6 inches; yield, 50 gallons a minute. Drilled 

in the bottom of an old open well and lies in the rock. The water is good only for 

drinking and garden use. It is said that when the well was first drilled the water 

had a very strong odor, which disappeared after the well had been used awhile. 

Data furnished by King & Mather.

Additional records of wells in the sandstone area of Connecticut.

[These wells were drilled by C. L. Grant, who has furnished the records. They presumably derive their 

water from sandstone, though a few may be in trap.]

No.o

?.

4

5

7

Q

10 

11

12i ^

14

15 

16 

17

18

19

20

91

w,

23

?4

25 *?6

28

29

30

01

32

Town.

.....do... ..........

.....do.............

.....do.............

.....do.............

.....do.......--.-..

.....do.............

..... do.. ......... ..

.....do.............

.....do.............

.....do.......-.--..

.....do............. 

... ..do.. .......... . 

.....do.............

.....do.............

.....do.............

.....do.............

.... .do..... ........

.....do.............

.....do.............

.....do............. 

.. ...do...... ...... -

.....do..... -..-....

.....do..... ........

.....do.............

.....do.............

.....do.............

.....do.............

Locality.

....................

Whitneyville......

.. ...do..... ........

.....do............. 

.....do............. 

-....do.............

.....do.............

.....do....:........

....................

Owner.

Hartford R. K. 

Berlin Brick Co ..................

.....do............................

Yale Brick Co... .................

T. H. & L. C. Koot ..............

W. F. Downer...................

Edw. Davis. ..................... 

Geo. W. Ives.....................

Hartford Woven Wire Mattress

Co.

W.C. Wade..... .................

H. E. Patten.....................

.....do............................

.-...do............................

Depth 

of 

well.

Feet. 

300

60

70

100

86

31

290

190 

208

100

50

67

56 

65 

58

50

50

36

38

68

246

180

125 

200

200

. 110

200

228

201

200

Depth 

to 

water.

Feet. 

22

11

8

19

18

12

17

61

50

55 

41

29

10

27

9 

13 

25

12

17

21

18

28

16

24

11 

0

11

10

2

11

140"

Yield 

per 

minute.

Gallons. 

120

11

14

8

is

8

20

3

OK

4O

15

7

10 

8 

30

7

8

3

10

20

50 

60

29

150

120

150

120

150

For additional details, see page 128.
GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS. 127

Additional records of wells in the sandstone area of Connecticut Continued.

No.

33 

34 

35 

36 

37 

38 

39 

40 

41 

42 

43 

44 

45 

46 

47 

48 

49 

50 

51 

52

; 53

54 

55 

56 

57 

58 

59 

60 

61 

62 

63 

64 

65 

66 

67 

68 

69 

70 

71 

72 

73 

74 

75 

76 

77 

78 

79 

80 

81 

82 

83 

84 

85 

86 

! 87 

88 

89 

90 

91 

92 

93 

94 

95 

96 

97 

98 

99 

100 

101 

102 

103 

1104 

105 

106 

107 

108 

109 

110 

111

Town.

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do............. 

.....do.............

.....do.............

.....do............. 

.....do.............

.....do.............

.....do.............

.....do............. 

.....do.............

.....do.............

.....do............. 

.....do.............

.....do.............

.....do.............

.....do.............

.....do............. 

.....do.............

.....do.............

do

Locality.

.....do............. ....................

.....do.............

.....do............. 

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do............. 

.....do.............

.....do.............

.....do.............

Plain ville.........

.....do.............

.....do.............

Rocky Hill........

.....do.............

.....do.............

.....do.............

Suffleld.. .........

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

Tariffville.........

.....do.............

West Suffleld.....

.....do.............

.....do.............

Owner.

.....do...........................

E. G. MeCune. ................. .

.....do............... ...... ......

W.S. Matter. ..................

Wm. O'Brien. . ..................

Wm. Rogers. .... ................

C. L. Bailey...................... 

H. G. Abbey.....................

Geo. E. Hurd....... -....-.....-

C. A. Green......................

A. M. Weber. ....................

A. B.Calef........ ...............

W. E. Bradley. ..................

.....do............................

Wm. Derby. .....................

A. W. Stanley...................

Coburn Land and Lumber Co...

.....do............................

.....do............................

H.H.Olds&Co.................

E. E. Pimm. ....................

Mrs. S. F. Robbins...............

J. G. Paradise.. . .................

F.L. Stiles... ....................

I. L. Stiles & Son. ...............

N. Terrell......... ...............

Connecticut Tobacco Corporation. 

Mrs. G. C. Willoughby. ..........

JEtna Nut Co. ...................

E. A. Fuller......................

G. I. Mix & Co...................

J.H.Yale........................

C. W. Michaels. ..................

Mrs. Kate Gallagher.. ............

Depth 

of 

well.

Feet. 

300 

318 

240 

159 

140 

170 

155 

57 

67 

110 

37 

62 

60 

37 

50 

63 

49 

110 

50 

50 

48 

35 

28 

50 

50 

37 

60 

50 

50 

50 

70 

65 

75 

 53 

75 

40 

195 

200 

60 

250 

80 

237 

173 

50 

200 

254 

103 

300 

245 

75 

67 

24 

91 

159 

73 

83 

102 

28 

50 

48 

25 

212 331* 

61 

66

40 

63 

45 

48 

60 

135 

100 

67 

90 

40 

110 

135 

53

Depth 

to 

water.

Feet. 

Flows. 

25 

25 

15 

29 

32 

25 

9 

19 

23 

0 

22 

20 

0 

20 

27 

20 

75 

10 

11 

21 

17 

12 

16 

11 

13

. 30 

12 

15 

10 

30 

18 

25 

5 

40 

18 

12 

38 

7 

13 

49 

18 

1 

Flows. 

3

12 

112 

35 

18 

15 

28

21 

14 

6 

2 

12 

22

125 

36 

34

24

6 

14 

6 

18 

13 

9 

6 

45 

118 

Flows. 

15 

20 

9

Yield 

per 

minute.

Gallons. 

250 

50 

45 

15 

10 

16 

12 

5 

2 

12 

7 

14 

3

11 

8 

11 

5 

9 

8 

11 

7 

5 

12 

8 

10 

2 

6 

11 

8 

8 

13 

5 

9

40 

32 

12 

10 

6 

5 

47

10

65 

60

58 

45

20 

5 

12 

18 

12 

35 

3Q

8

4 

17 

30 

4 

5

6 

10 

3 

3 

4 

12 

40

4 

23 

35 

3
128 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

Additional records of wells in the sandstone area of Connecticut Continued.

No.

m

113 *114

115

116

117

118

119

120

121

Town.

West Hartford. . . .

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

Wethersfield......

.....do.............

Windsor..........

Locality.

.....do............

Owner.

L. N. Burt. ......................

P.H.Rellly.. ...................

Mrs. E. W. Taleott... ............

J. H. Rabbett. ...................

C. D. Reed.......................

Depth 

of 

well.

Feet. 

30

52

175 I'OO

51

195

30

70

101

150

Depth 

to 

water.

Feet. 

15

13

15

13

23

39

2

30

12

100

Yield 

per 

minute.

Gallons. 

12

6

40

30

8

6

12

35

18

4

NOTES.

26. Depth, 200 feet; diameter, 6 inches; yield, 60 gallons a minute. The ordinary yield of the well is 25 gallons a minute and it flows if left standing. The 

water is too hard for boilers.

114. Sunk in the "Posterior" trap sheet, which at this locality is comparatively 

thin. The thickness of the trap has not been determined, but at least two-thirds, 

and possibly three-fourths, of the depth of the well must be in the "Posterior" 

shales which, underlie the sheet, and it is very probable that the water does not 

come from the trap at all, but from the underlying shale.

WELLS IN TRAP.

Owing to the rugged topography of the main trap ridges few 

houses are built on them and consequently few wells haVe been 

drilled in rock of this character. In the vicinity of Hartford there 

are several wells which have been sunk directly into trap and obtain 

yields of 2 or 3 gallons a minute. The greater number of successful 

wells in rock of this type pass entirely through the trap and obtain 

their supplies from the underlying sandstone or shale.

All exposures of trap show an extraordinary development of 

jointing, and in cliffs, as at East Rock and West Rock in New Haven, 

the vertical joints cut the formation from top to bottom and usually 

show weathering, indicating the past action of water. In large trap 

exposures it is unusual to strike streams of water, which are so characteristic of the quarries in crystalline rocks, although it is said that 

in one of the Hartford quarries two days after a heavy rain water 

will begin to seep out of the joints at the base.

The field evidence indicates that the chances are small for obtaining water by drilling on the higher parts of the trap ridges, as the 

rock is so completely fractured at the surface as to allow the water 

to pass*through and escape at lower levels, and at a short distance 

below the surface the joints are too tight to admit water in quantity. 

On such ridges, however, supplies may generally be obtained by 

shallow dug wells in the overlying drift.
GROUND WATER IN TEIASSIC SANDSTONES AND TKAPS. 129

Some interesting wells in trap have been described a by M. L. 

Fuller and W. H. C. Pynchon, as follows:

W. E. Pratt [Rocky Hill]. This well is located in the thin "Posterior" sheet of trap. 

It was drilled in the bottom of an old open well, 20 feet deep, which entered the rock 

for a distance of 6 feet. From this point the well was drilled 30 feet through trap, when 

it broke into the underlying sedimentaries, which it pierced to the depth of 1J feet. 

This well therefore gives a section of 14 feet of soil, 36 feet of trap, and 1J feet of sedimentary rock a total depth of 51| feet. This brings the bottom of the well about 50 

feet above the surface of Connecticut River, which flows by it only a few hundred feet 

eastward. The diameter of the well is 6 inches and the maximum amount of water 

obtainable is a little less than 1 gallon a minute. The well pumps dry in thirty 

minutes. The water is fair for drinking, but is excessively hard.

J. K. Green [Rocky Hill]. Depth of well, 26 feet; depth of water, 25 feet; diameter, 

6 inches; yield not given. The well is in trap rock. Data by Grant.

Hotel Russwin [New Britain]. The depth of the well is 152 feet, and the depth of the 

water at the lowest 130 feet, but if the well is allowed to stand the water flows at the 

level of the engine-room floor, which is 10 feet below grade. The ordinary consumption is fully 10,000 gallons a day. The water is very pure and can be used for all 

purposes.

[Wells at Cedar Mountain.] The wells * * * at Cedar Mountain, southwest of 

Hartford, * * * are on the property of Dr. Gordon W. Russell, who sunk the wells 

largely as an experiment and who has shown much interest in scientific matters. The 

mountain is a part of the ridge of the "Main " trap sheet, and has a maximum elevation 

of about 360 feet above the sea. Its western face is very steep, dropping 250 feet to the 

plain within a distance of two-fifths of a mile, and is actually precipitous near the 

summit. The eastern face slopes more gradually, dropping about 120 feet to the valley 

occupied by shales, about three-fifths of a mile distant. It is in all a typical trap ridge.

Well A is an ordinary open well and was dug to supply the needs of the farmhouse. 

It was opened 9 or 10 feet to the rock, but the water became shallow in summer. It was 

then sunk 1 or 2 feet into the loose, greatly jointed surface trap and has since given an 

abundance of water for domestic uses. The supply, however, fluctuates regularly with 

the wetness or dryness of the season. From the well mouth the mountain side with its 

drift covering rises steadily for two-fifths of a mile to the west till it reaches the crest, 

which is about 100 feet above the well. The supply is clearly the surface water contained in the soil and in the heavily jointed upper surface of the trap, the source also 

of a little stream which lies a little farther up the ridge.

Well B is located about 200 feet south of well A. It passes through 9 feet of soil and 

then through about 290 feet of trap rock, at which point the string of drilling tools 

wedged fast, possibly along a joint plane. The well is 6 inches in diameter. On 

illuminating it brightly for a considerable depth by light reflected from a mirror, it 

appeared that no water came into it except from the shattered upper surface of the trap 

sheet, as in well A. The drill had no't entered the underlying sediments when the well 

was visited in 1902, notwithstanding the fact that the bottom of the well was much 

below the level of the western plain.

Well C is located about three-fourths of a mile farther south and a little farther east 

than the other two wells. It has a depth of 103 feet. It was thought from the residue 

brought up by the sand bucket that the well entered the sedimentary beds below, but 

in view of the record of well B and the thickness of the "Main" sheet this is extremely 

doubtful. Water was struck at a depth of 38 feet from the surface in a joint, the yield 

being 32 gallons an hour. At the present depth the well is capable of giving 90 gallons 

an hour, the water probably coming through joints from a level below the well bottom

a Water-Supply Paper U. S. Geol. Survey No. 110,1905, pp. 88, 89,100,101,103,

463 IRE 232 09 9
130 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

and rising to. within 25 feet of the surface. During the drilling light was reflected down 

the bore and water was seen coming in through the trap, and in the opinion of the 

driller, Mr. H. B. King, of Hartford, from the downhill side. However this may be, 

we have here a well near the summit of the mountain whose bottom is above the level 

of the lowlands on either side, with water coming in through the trap and rising to a 

point about 175 feet above the plain three-fourths of a mile to the west and about 70 feet 

above the valley one-fourth of a mile to the east. The top of the well is abort 280 feet 

above sea level.

PRACTICAL APPLICATIONS.

YIELD OF WELLS.

The sedimentary rocks of Connecticut possess large storage capacity 

between strata, in joints, along faults, and within the rocks themselves, and it is but rarely that a well sunk into sandstone, conglomerate, or shale does not obtain water from one or all of these sources in 

sufficient amount for domestic purposes. No enormous supplies running into thousands of gallons a minute, such as are obtained elsewhere in the United States, are found, and in some parts of the State 

difficulty has been experienced in obtaining sufficient supplies for large 

manufacturing plants. Wells in sandstone offer the best chances for 

large supplies, shale coming second, and conglomerate third. A few 

wells in conglomerate at New Haven encountered dry rock from top 

to bottom of the drill hole. One well on George street, 500 feet deep, 

obtained no water after passing through the cover of glacial drift, and 

another well remained dry to a depth of 4,000 feet. Such wells should 

not be abandoned "without a thorough test of every water horizon, 

however small. The casing, if possible, should be raised above the 

level of the water-bearing bed, a pump inserted, and the supply measured. When it is impossible to remove the casing, it can be destroyed 

at the water horizon by a shot of nitroglycerine, which will also at the 

same time tend to loosen up the surrounding rock and increase the 

flow. Supplies have frequently been developed at horizons which 

were not at first thought worthy of testing and which were originally 

drilled through without stopping and cased off." a Of the 194 wells 

recorded on pages 116-123, only 11, or 5.6 per cent, failed to obtain 

2 gallons a minute, the minimum amount desired for domestic purposes. Drillers are naturally averse to reporting well failures, yet 

considering the number of successful wells of which no records are 

available the above percentage is probably close to the facts.

The average yield of 112 wells in sandstone reported in the tables 

is 27 J gallons a minute, the largest being 350 gallons and the smallest 

two-thirds of a gallon. The 107 wells included in the supplementary 

list furnished by C. L. Grant (pp. 126-128) have an average yield of 

26 gallons. As a rule, the well that encounters the largest number of 

joints and bedding planes has the largest supply of water, and there

o Water-Supply Paper U. S. Geol. Survey No. 110, 1905,
GEOUND WATEE IN TEIASSIC SANDSTONES AND TEAPS. 131

is, therefore, an increased yield with increased depth. This statement, however, is true only for wells less than about 300 feet in depth 

(see below), and many exceptions are to be noted. A well which 

strikes a favorable bedding plane between sandstone and shale, or 

drains water from a contact of trap and sandstone, or strikes a fault 

zone may yield large amounts at slight depths. In fact, the water 

moves so freely through the rock that wells sunk to lower levels or 

located more advantageously may drain a neighboring well, thus 

making it useless. (See pp. 108-109.)

The abundant and uniformly distributed rainfall of Connecticut 

(see p. 24) and the freedom of circulation of ground water in the 

Triassic sediments account for the slight variation in yield throughout 

the year. Few drilled wells in rock show seasonal variations. A 

few record a decrease in summer; in several others the supply has 

increased since the wells were dug. Mr. Grant is of the opinion that 

"in general, the wells in the Triassic area have increased their flow 

with age." This seems to be due to the enlargement of seams and 

joints caused by the washing out of the decomposed rock ("clay"). 

"Water from black shale," says Mr. Grant, "clears up in about two 

hours, but that from red shale remains cloudy for a week or two." 

In many wells the water has become clearer as the years have passed. 

The height at which water stands in the well is also remarkably 

uniform.

DEPTH OF WELLS.

Two geologic myths seem to have attained the dignity of facts in the 

popular mind; one is that ore veins increase in richness with increasing depth, the other that water is more abundant and of better 

quality in proportion as it comes from greater depth. So far as 

Connecticut's water supply is concerned, the facts are not in accord 

with popular opinion. Though water is drawn from sandstones at 

all depths between the surface and 800 feet, yet the greatest number 

of failures are in wells exceeding 400 feet in depth. The reason for 

decreased supply at greater depth is the decrease in the number of 

joints and the tightening of both joints and bedding planes. The 

average depth of 287 wells, including the three deepest, one of them 

4,000 feet, is 144 feet. At $2.26 a foot, which is the average cost of 

67 wells, the cost of the average well is $335.44. The depth to the 

principal water horizon is even less than the depth of the wells. In 

63 wells with an average depth of 127 feet the principal source of 

water was 97 feet below the surface. The depth to the surface of the 

water in 144 wells in sandstone averages 23 feet. Of the 314 wells 

recorded in sandstone, shale, and conglomerate, 75 per cent are less 

than 200 feet deep, 90 per cent less than 300 feet, and only 5.6 per 

cent more than 400 feet; 47 per cent, including some of the best 

wells in the Connecticut Valley, are less than 100 feet deep.
132 UNDERGROUND WATEK RESOURCES OF CONNECTICUT.

In view of these facts and in consideration of the increased difficulty and cost of deep-well construction, it is good practice to abandon 

a well that has not obtained satisfactory supplies at 250 to 300 feet. 

Two or three wells 200 feet deep could be drilled at the cost of one 

500-foot well, and the prospect of obtaining water would be greatly 

increased. In case a well is abandoned, the new location should be 

as far as possible from the old. In fractured rock favorable conditions may be found a few hundred feet distant. Wells in shale may 

be sunk to greater depth before abandoning the site, as is indicated 

by the fact that of sixteen deep wells in shale two are between 100 and 

200 feet deep, five between 200 and 300 feet, four between 300 and 

400 feet, two between 400 and 500 feet, and three more than 500 

feet. 0

QUALITY OF WATER.

The table of analyses shows that the composition of water in Triassic strata varies greatly, for wells only a few hundred feet apart 

may show marked differences in mineralization. One reason for 

this can be traced primarily to the inclination of the strata. As the 

rocks dip eastward at an angle of 15° or more, the area tributary 

to each well is rather small; a 500-foot well, for instance, would have 

a supply basin of considerably less than one-sixth of a square mile. 

Therefore different wells are supplied from different sets of beds, 

which differ from each other in their composition and consequently 

in their effect on the water passing through them. In general, the 

waters of the Triassic are so highly mineralized as to be undesirable 

for boilers without purification, thus strongly contrasting with those 

obtained from wells in crystalline rock. (See p. 168.) They are not 

too hard for cooling, washing, and certain other manufacturing purposes, nor for domestic use. Many wells show 500 to 2,500 parts 

per million of dissolved solids, including not only incrusting carbonates, but also the more undesirable sulphates. The water percolating 

through sandstone and shale is usually harder than that in joints 

and in bedding planes, and water of different quality may come from 

each stratum.

TEMPERATURE.

The temperature of well waters is determined by the depth from 

which they are drawn. At depths less than 50 feet the temperature 

of the water will roughly vary with the temperature of the air, which 

for Connecticut is 45° for the spring season, 67° in the summer, 51° 

in the fall, and 36° in the winter.6 Below about 50 feet the temperature increases at the rate of 1° for each 60 feet.

a Water-Supply Paper U. S. Geol. Survey No. 110, 1905, p. 99.

& These figures are based on the mean seasonal temperatures of Storrs, New Haven, and Cream Hill, 

Combined, for the years 1893-1903,1873-1903, and 1897-1907, respectively, as given on pages 24, 25,
GROUND WATER IN TRIASSIC SANDSTONES AND TRAPS. 133

HEIGHT OF WATER IN WELLS.

Water in wells tends to reach a certain level, which remains constant with the exception of slight seasonal variations and changes 

produced by pumping. The height at which this water level stands 

depends on the character and permanency of the supply. In some 

wells the water stands at the rock surface, in others above or below 

that surface, and in a few it is under hydrostatic pressure and reaches 

the earth's surface as a flow. The topographic location is another 

factor in determining water level in wells, for, as shown in the table 

below, the water in valleys tends to rise above the rock floor, whereas 

about half of the wells on hills and slopes maintain a level within the 

rock. Considered as a whole, the water level in the Triassic sandstone 

stands 23 feet below the surface of the ground.

Height of water in wells.

Location.

Hills. . .................................................

Number of 

wells 

averaged.

28 

59 

29

Percentage with water level 

Below 

rock 

surface.

46.4 

28.8 

48.3

Above 

rock 

surface.

50 

67.8 

44.8

Even with 

rock 

surface.

3.6 

3.4 

6.9

FLOWING WELLS.

As stated on page 49, the primary conditions for flowing wells are (a) 

strata capable of holding large amounts of water, overlain by strata 

which are relatively impermeable; (&) outcrops of the strata where 

they may receive the surface water, and (c) a suitable dip to the rock. 

All these conditions are present in the Triassic areas of Connecticut. 

Sandstone and shale are interstratified, forming the couple which 

produces artesian wells in the Dakotas, New Jersey, Texas, and elsewhere. Lava flows alternate with the sandstones and shales, a condition which makes an artesian basin in parts of Idaho.a The edges 

of the water-bearing strata are well exposed, the rainfall is ample, and 

there is a dip to the strata of 15° or more to the southeast. Under 

normal conditions the Connecticut lowland would therefore form an 

unusually good artesian basin, and wells sunk anywhere along the. 

western border of the Triassic area would procure large supplies, as 

shown in figure 19. This opportunity of obtaining artesian wells is 

almost entirely destroyed by two circumstances. First, the region is 

crossed by a series of faults and the strata are broken into huge blocks 

uplifted on the west side. The continuity of the water-bearing beds 

is therefore destroyed. But, even under these conditions, artesian

a Russell, I. C., Bull. U. S. Geol. Survey No. 199,1902, pp. 178-180.
134 TJNDEEGEOTJND WATEE EESOUECES OF CONNECTICUT.

basins of moderate extent (fig. 20) would be present were it not for 

the fact that the strata between the fault lines are cut by joints which

./;'-<-:i 0

run in all directions and are but short distances apart, several being 

present in each 100 feet (fig. 21). The continuity of the beds is thus
GBOUND WATEE IN TEIASSIC SANDSTONES AND TEAPS. 135

further disturbed and the existence of unbroken beds, either as water 

bearers or water retainers is made impossible. All the strata, including the lavas, have taken part in 

this faulting and jointing, with the 

result that instead of numerous 

flowing wells throughout the region, 

there are a few the waters of which 

rise slightly above the surface. 

Some of the flowing wells derive 

their water from local bedding 

planes in rock; the others from the 

contact of rock with the cover of 

glacial till.

LOCATION OF WELLS.

Two considerations will usually 

control the location of wells the 

amount and the quality of the water 

desired. To insure good quality 

requires a location selected with 

reference to freedom from contamination by drainage from barns, cesspools, houses, factories, etc. High 

ground with a surface cover of glacial material is a better location than 

bare rock. A well in low ground 

will usually yield more water at less 

expense, but the danger of contamination is greater. When it is proposed to construct a well, the condition of existing wells in that 

vicinity or in the same rock type 

should be studied with care. The 

direction, opening, continuity, and 

number of joints in the rock should 

be observed; also the dip or inclination of the strata and the presence of beds of shale or trap.

It is to be remembered that water 

in bedding planes passes up as well 

as down an inclined surface. The 

usual experience, as stated by C. L. 

Wright, of Augerville, is to find 

water at less depths on eastern 

slopes of hills than on western slopes, because of the eastward dip of 

the strata. There are numerous examples of both wells and springs,
136 UNDERGROUND WATER RESOURCES OP CONNECTICUT.

however, which indicate that water flows up the slope after being fed 

into the bedding planes by joints. A well at Thompsonville, illustrating movement of this type, is described on page 124. The water 

in this well is 25 feet higher than the water in Connecticut Kiver, 

near by, which might otherwise be its source; the water-bearing bed 

does not outcrop farther east; and there seems to be no source of supply other than joints or faults. A well at the "old Talcott tower," 

near the edge of a 700-foot cliff, is believed to derive its meager supply 

from water moving up the 15° slope from the east. The hundreds of 

springs located along the western faces of low sandstone ridges that 

derive their water from a combination of joints and upward-sloping 

bedding planes may be illustrated by a spring on the estate of A. I. 

Ward, at Mount Carmel. (See fig. 22.)

FIGURE 22. Spring deriving its supply from joints and upward-sloping bedding planes. 

STATISTICAL TABLES.

Yields of water at various depths in the rock below the covering of surf ace material. 

"Vol." = average yield in gallons per minute; "No." = number of records from which the average is taken.]

Depth in feet.

0-30................................

30-50................................

70-90................................

90-110...............................

Vol.

4.7

11.1

17.7

20.3

No.

3

40

44

21

29

Depth in feet.

110-200. .............................

300-400. .............................

400-500. .............................

500-650. .............................

Vol.

27.6

56.4

40.7

185.0

40.0

No.

53

41

7

6

5

The foregoing table requires a little explanation, especially in 

regard to wells more than 400 feet in depth, where the recorded yield 

of 185 gallons a minute does not represent a true average. This estimate is the average of the yield of five wells in Hartford and one in 

South Manchester, in both of which places unusual conditions prevail. 

Moreover, the principal source of water of these wells is at a less 

depth than 400 feet, so that the same yields would have been obtained 

if drilling had stopped at 300 to 400 feet. Considered in this light, 

the data from wells 400 to 500 feet in depth indicate the presence of
GKOUND WATER IN TEIASSIC SANDSTONES AND TKAPS. 137

water in bedding planes down to 400 feet and should go to swell the 

average yield of wells 200 to 300 feet and 300 to 400 feet deep. 

The figures for wells more than 500 feet in depth likewise convey 

a wrong impression of the relation of yield to depth. The five wells 

included in the table report yields of 1, 2, 7, 75, and 125 gallons a 

minute. In all these wells the principal source of water is less than 

300 feet and in one well less than 50 feet below the surface. When 

these facts are taken into account the yield of wells more than 500 

feet in depth drops to an average of less than 10 gallons a minute.

Average yields of wells in various locations.

Location.

Hills..........................................................................

Plains.........................................................................

Average yield 

(gallons per 

minute).

64.3

44.4

17.7

 42.7

Number of 

records.

6

24

14

46

Relation of level at which water stands in wells in various locations to surface of rock which 

marks bottom of overlying drift. «

Location.

Hills. . .......................................

Plains........................................

Number.

28

8

29

51

Percentage of 

wells with 

water level 

below rock 

surface.

46.4

12.5

48.3

31.3

Percentage of 

wells with 

water level 

above rock 

surface.

50.0

87.5

44.8

64.7

Percentage of 

wells with 

water level 

even with 

rock surface.

3.6

0.0

6.9

4.0

a A summary of the results for all wells may be found on p. 133. 

Average depth from surface to water level in the well.

Location.

Hills............................................................................

Plains...........................................................................

Depth to 

water.

Feet. 

31.9

16.9

21.2

19.9

Number of 

records.

37

10

26

53

Average depths, in feet, of surf ace material, of rock, and of the entire well for the records at 

hand, exclusive of wells more than 400 feet in depth and of wells known to be dry.

Location.

Hills...................................................

Average 

depth of 

surface 

material.

82.5

39.4

20.4

39.3

Average 

depth in 

rock.

199.5

73.9

95.1

93.8

Average 

total 

depth.

282.0

113.3

115.5

133.1

Number of 

records.

6

30

22

50

NOTE. Average total depth of all these wells is 161 feet.
CHAPTER VI.

WATER IN THE GLACIAL DRIFT. 

INTRODUCTION.

Exposed rock surfaces in Connecticut are confined largely to hill 

summits, cliffs, river valleys, and the shore line, and their combined 

area probably amounts to less than one-tenth of 1 per cent of the 

4,965 square miles constituting the area of the State. Where rock 

outcrops are absent, glacial drift forms the surface covering. The 

three classes of glacial material in which ground water occurs are 

till, stratified drift, and clay.

CHARACTER AND WATER CAPACITY OF DRIFT.

TILL.

Till varies in texture from loosely compacted bowlders a few 

inches to several feet in diameter to a firm, dense, securely cemented 

mass of small rock fragments and clay, popularly called "hardpan." 

The composition of an average deposit of till is shown by the following mechanical analysis of the so-called Triassic stony loam from 

Bloomfield:

Mechanical analysis of stony loam from Bloomfield. a

Silt...........................................................................

Clay..........................................................................

Loss at 110° C.. ...............................................................

Loss on ignition. ..............................................................

Diameter of 

grains.

Millimeters. 

2 1

1 - .5

.5 .25

.25 .15

.1 - .05

.05 - .01

.01 - .005

.005- .0001

Per cent.

2

3.35

8.60

31.25

34.22

4.35

6.20

6.57

1.36

2.03

a Field Operations, Div. Soils, U. S. Dept. Agr., for 1899, p. 131.

The soil represented by the foregoing analysis is the fine earth after 

coarse gravel and bowlders, varying in size from an inch to 7 or 8 feet

138
WATER IN THE GLACIAL. DRIFT. 139

in diameter, have been removed. The amount of gravel and undecomposed rock invariably exceeds 5 per cent, and may exceed 50 

per cent.

The heterogeneous character of till makes it impossible to estimate 

its water-bearing capacity for any large area. The amount of clay 

present, the size, shape, and -composition of the constituent bowlders, 

and the degree of compactness vary within wide limits, and therefore 

determinations of absorptive ratios apply only to the sample tested. 

Determinations of water capacity are made still more uncertain by 

the presence of irregular deposits of sand and gravel included within 

the till. The loosely compacted till has practically the capacity of 

conglomerate; the "hardpan" variety is almost as impervious as shale.

A mass of till collected near Yale Field, New Haven, was found 

after five days of continuous drying to weigh 22 pounds. After soaking in water for one day and being allowed to drain the added water 

had increased its weight to 24.87 pounds, a gain of 2.87 pounds, which 

showed an absorption percentage of 11.55, or 3.46 quarts to a cubic 

foot of till. This is probably not far from the average capacity of 

till in Connecticut.

STRATIFIED DRIFT.

Stratified drift consists of sands and gravels with local clay bands 

and is composed of rounded waterworn fragments of the more 

resistant rocks, like granite, trap, and quartzite, together with an 

abundance of grains of quartz, mica, garnet, magnetite, etc. It 

owes its origin to streams, and especially to the water produced by 

the final melting of the continental ice sheet. As contrasted with 

till, stratified drift occurs in layers of various degrees of coarseness, 

depending on the velocity of the stream which deposited the debris.

It must not be supposed that the stratified drift presents uniform 

conditions over large areas, for there are several types of the drift, 

each varying in texture, structure, and topographic appearance, in 

accordance with their method of formation. Flood-plain deposits 

and terraces contain numerous fine clayey layers. Delta deposits 

made in bodies of standing water exhibit strata of sand, gravel, and 

silt inclined at various angles, and the different sets of beds contain 

water in different amounts. 66 The grains composing sand and gravel 

come into contact with one another, but are so placed that there is 

much unoccupied space between them. Sand is practically sandstone with cementing material removed and the water capacity 

proportionately enlarged. As a reservoir of ground water, stratified 

drift is therefore very important. Such material has been found to 

contain an amount of water equal to over 30 per cent of its volume.

a Crosby, W. O., Water-Supply Paper U. S. Geol. Survey No. 145, 1905, pp. 177-178.
140 UNDERGROUND WATEB RESOURCES OF CONNECTICUT.

The proportions of different sizes of grains in the average sand of 

the New Haven plain, are shown by samples from four localities 

analyzed by Freeman Ward, as follows:

Size of grains in sand from New Haven plain.

Size of grains.

ess than ^ inch. .............................................

1.

0.9

.7

1.1

97.3

100.0

2.

2.3

2.7

10.0

85.0

100.0

3.

0.6

1.6

5.5

92.3

100.0

4.

0.8

1.6

6.3

91.3

100.0

Rain water is freely imbibed by stratified drift, and accordingly the 

surface dries very shortly after showers, and this material furnishes 

little water to streams. The water, however, stands close to the 

surface and the sands of plains and kames are thoroughly saturated. 

On the North Haven sand plain there is "plenty of moisture a few 

inches below the surface, even in a protracted drought.0

CLAY.

The clays of Connecticut are largely the result of the deposition of 

fine material in lakes of glacial origin. They are accordingly stratified and usually contain layers of "strong clay" interbedded with 

sandy clay, quicksand, and sand of coarser textures. Clay consists 

of minute particles of kaolin, quartz, feldspar, mica, iron ores, etc., 

and when compacted under pressure these fragments are so nearly in 

contact as to give little pore space. However, the very small openings 

between the grains permit the access of much .water, for each space 

acts as a capillary tube and the clay is expanded. The fine-grained 

clays, therefore, absorb and retain large amounts of water. That 

abundant water is present is indicated by the mud cracks in exposed 

clay surfaces and by the shrinkage which takes place on drying 

an amount often over 10 per cent. The total amount of water in the 

brick clays of Connecticut is usually between 30 and 40 per cent. 

Most of the commercial clays of the State ' 'contain enough water to 

make them highly plastic, so that they can be tempered without addition of more water." 6

THE DRIFT AS A WATER RESERVOIR.

The mantle of glacial drift spread over Connecticut is perhaps the 

most important single factor in the ground-water supply of the State, 

because it contains abundant water in itself and controls the supply

a Britton, Bull. Torrey Bot. Club, vol. 30, 1903, pp. 571-620.

6 Loughlin, G. F., The clays and clay industries of Connecticut: Bull. Connecticut Geol. and Nat. Hist. 

Survey, No. 4,1905, p. 63.
WATER IK THE GLACIAL DRIFT. 141

of water to the underlying rocks. The bed rock exposed on the summits and sides of hills is not in a position to absorb water. It is 

apparent that the greater part of any rainfall on such surfaces would 

run off immediately; in fact, a locality where even 2 per cent of the 

precipitation was absorbed by the rock would be exceptional. Even 

where there are wide-open cracks on the rock surface, the greater 

part of the water would run off before it could be absorbed by the 

few joints, which, not far below the surface, are so tight as to allow 

very slow passage to the water.

On the other hand, where the rock is covered by glacial material 

the water does not run off rapidly but is absorbed by layers of porous 

sandy soil, from which in turn a considerable portion of the precipitation passes down into the rock fractures. Numerous shallow-dug 

wells indicate that the lower portion of the drift is in a saturated condition, being always ready to supply water to joints or faults or bedding planes below. The saturated belt in the surface material forms 

a constant reservoir, kept filled by uniform precipitation, from which 

water is delivered to the 

rocks to compensate for the 

amount removed by springs 

and wells. The sandy and 

gravelly portions of the drift 

are the most important reservoirs for supplying water 

to rock seams, for they carry

a large quantity of Water and FIGURE 23. Section of hilltop showing suitable catchment

allow ready passage* the and reservoir conditions for a water supply to the rock

 11 i -i TII fractures. clayey till, which may hold

nearly as much water, allows very slow passage. The character of the 

overlying drift is, therefore, by its difference in permeability, largely 

determinative of the amount of water supplied to the underlying rock.

The condition of the rock surface is another factor in the absorption 

of the water. At many localities the rock is marked by minor irregularities, due to a scooping out of the rock by glacial erosion (see fig. 

23), or to a dam of impervious glacial material. These small depressions in the rock serve as guiding channels to the circulation of 

ground water in the drift, and joints opening into these depressions 

have better opportunity for the collection of water than those intersecting the rock surface at intermediate and higher points. Many 

depressed areas which have no outlet occur in the rock. In such 

basins the water collects and has no escape by seepage into rock 

joints, and evaporation is relatively unimportant where the drift has 

an appreciable thickness.

Vertical joints are evidently more important than horizontal joints 

in giving opportunity for the entrance of subsurface water from the
142 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

drift. Owing to their parallelism to the rock surface many of the 

horizontal j oints pitch downward when they reach the ground surface 

and consequently do not offer good conditions for the entrance of 

water, although in exposures of bare rock the fractures lying at low 

angles tend to absorb more of the precipitation than the vertical 

joints.

WATER BED AT CONTACT OF ROCK AND DRIFT.

The glacial drift rests directly upon bed rock without any intervening soil or disintegrated material. (See fig. 24.) There is a sharply

drawn line of contact between the till, stratified 

drift, or clay and the 

gneiss, schist, sandstone, 

or other rock beneath. 

The contact forms a water 

bed, the supplies from 

which are larger and more 

permanent than those of 

any bedding plane in the 

Triassic sediments or set

FIGUPE 24. Section showing common relation of rock surface Q-f joints in the crvstalline 

to overlying drift. J » i i

rocks. As shown above,

the drift is filled with water, which percolates downward more rapidly 

than it can be imbibed by the rocks. The result is an accumulation 

of water at the rock surface which brings the drift to the point of 

saturation. In this wray the layer immediately above the rock is supplied with water to 30 to 40 per cent of its volume, an amount equal 

to 2.24 to 2.99 gallons a cubic foot. Wells sunk to the contact of 

drift and rock show a large yield. Three wells, owned by the Bradley 

& Hubbard Manufacturing Company, at Meriden, reach rock at 

depths of 203, 208, and 256 feet, and have a combined yield of 100 

gallons a minute.

WELLS IN TILL AND STRATIFIED DRIFT.

Probably three-fourths of all the wells in the State are shallow, 

open pits of large diameter, sunk in glacial material. (See fig. 25.)

FIGURE 25. Generalized section showing relation of rock to glacial drift. A, Layers of sand and gravel, 

partly saturated with water; B, bowlder clay; C, crystalline rock.
WATER IN THE GLACIAL DRIFT. 143

;Fine;

Gravel

Owing to the uniform rainfall, these wells yield sufficient water for 

domestic purposes, but the supply is uncertain and is subject to 

marked seasonal and annual variation. The data collected for this 

report, taken in connection with investigations made by the State 

board of health, indicate that such wells are not to be recommended 

either for large yields or for unqualified purity.

WATER HORIZON.

The principal water horizons in glacial drift are the porous sandy 

beds confined between beds of material more or less impervious. The 

water-bearing layer may be 

sand or gravel, or even clay 

containing a small proportion of sand, and it may lie 

between layers of till and 

stratified drift, between different members of a strati - 

fied-drift series, or between 

the till and bed rock. At 

Stafford Springs John McCarty finds that wells in 

drift, which average about 

20 feet in depth, are sunk 

through a top covering of 

loam, followed by 2 to 10 

feet of sand and gravel, and 

then by a layer of hardpan 

5 to 20 feet in thickness. 

The water comes either from 

the sand above the hardpan or, more commonly, 

from the contact between 

the hardpan and the underlying rock. In many places 

the till acts as a confining 

bed to retain the water 

stored in both sand and 

gravel. In fact, the hardpan variety of till exerts its chief influence as an impervious bed to 

limit the percolation of ground water. This relation is illustrated 

by the well of Mr. Coppus, at South Willington (see fig. 26), where the 

water enters in quantity at the junction of sand and underlying till. 

The most favorable water horizon, however, is in the drift, the zone 

lying immediately over bed rock, as explained on page 142.

sand/;

FIGURE 26. Diagram, of well at South Willington, showing 

water horizon at contact of till and stratified drift.
144 UNDERGROUND WATEK RESOURCES OF CONNECTICUT.

There is usually sufficient variation in the texture of the stratified 

drift to furnish pervious and impervious layers in contact. A slight 

variation in fineness of grain may be all that is necessary to concentrate the water along one plane, but the most favorable relations 

exist where sand overlies clay. In the brick yards at Montowese, 

Berlin, and North Haven water is present in quantity along the upper surface of the clay beds, and in other localities sandy layers 

between beds of clay furnish abundant water supplies. The whole 

North Haven sand plain is a good illustration of this relation. The 

area is underlain at a depth of 20 to 30 feet by beds of clay 5 to 20 

feet thick, on top of which lie sand and gravel. Water sinks so readily 

into the sand that vegetation is practically absent from this area, 

but wells sunk to the clay bed find abundant water, and where the 

strata are shown in sections, as along Quinnipiac River, there is a line 

of springs and seepages. In certain localities the bed of clay holds 

the water under hydrostatic pressure, and when this cover is pierced 

by a well the water rises nearly or quite to the surface.

Wells sunk in till which does not contain sandy layers have no 

definite water horizon. In such wells the water is seen to form as a 

film and to drip from the surface, or to ooze out in small amounts 

around some of the larger bowlders. The circulation of water in 

such material is much retarded, and the wells are accordingly likely 

to vary much in yield.

DEPTH AND YIELD.

The average depth of the recorded wells in till is 24 feet, which is 

probably 5 feet too much, as an average for the State, because of the 

omission of a large proportion of shallow dug wells. The greatest 

depth reported is 151 feet and the least 7 feet. A few wells located 

at the contact of drift and bed rock flow at the surface.

The average depth of 83 wells in stratified drift is 48.3 feet, a 

figure probably 10 feet in excess of an average made by including 

several thousand shallower wells sunk in this material. The deepest 

well in drift is 110 feet deep and the least depth recorded is 7 feet, 

but the tables do not include numerous wells with depths of less 

than 10 feet that are known to exist.

These wells, both in till and stratified drift, probably procure all 

the water necessary for domestic purposes, for which they are largely 

used; by sinking to greater depths they could obtain much larger 

supplies. The average thickness of the drift cover over the sandstones is 38.4 feet and over the crystalline rocks 36 feet, an average 

of about 37 feet for the State. It is readily seen that the wells in 

till, with an average depth of 24 feet, do not penetrate to great depths 

in this glacial material. The wells in stratified drift are sunk deeper 

and take more advantage of the opportunity offered to procure 

large supplies from a considerable thickness of drift. In case more
WATER IN THE GLACIAL DRIFT. 145

water is desired, it is advisable to sink a well in drift to bed rock or a 

few feet into the fractured upper surface of the rock itself. These 

are the conditions, as explained above (p. 142) under which the largest 

yield of water may be obtained with a minimum depth of well.

The number of wells recorded of various depths in the till and 

stratified drift is shown in the subjoined statement.

Depths of wells in till and stratified drift.

Depth, In feet.

0-30............................

30-50...........................

50-70...........................

Number of wells.

Till.

84 '8 

1

Stratified 

drift.

31 

21 

9

Depth, in feet.

70-90.......................'...

110-200

Number of wells.

Till.

1

2

Stratified 

drift.

7 

6 

5

QUALITY OF WATER.

Till and stratified drift, alike, are composed of fragments of all 

sorts of rock, and it is therefore to be expected that the quality of 

the water should vary within wide limits, with reference to both 

depth and location, and that water from different depths and from 

different locations should be unlike in character. The waters of 

wells in till derived from sandstone and limestone are sure to contain compounds of calcium, magnesium, etc., making them hard, 

while wells sunk in drift composed of fragments of crystalline rocks 

are much more likely to yield soft water. Wells in till are more 

liable to have hard water than those in stratified drift, because the 

water circulates slowly and with difficulty in material of this sort 

and, accordingly, has an opportunity to take larger amounts of mineral matter into solution. The tables of wells in till show 45 yielding hard water, 38 soft, and 11 medium in a total of 94 wells. In 

stratified drift 25 wells are reported to yield hard water, 30 soft, and 

4 medium out of a total of 59.

Most wells in drift, especially if they are shallow and open and of 

large diameter, contain impurities. Wells of this character, especially if they have been dug a number of years and are located near 

buildings, are so liable to contamination that an examination of the 

water should be made at short intervals. In thickly settled districts the water in shallow wells is often dangerous. Many wells 

near the beach sunk in stratified drift give brackish water, although 

a number of instances to the contrary may be cited. Wells in till 

are much less liable to contamination by salt water, and a number 

of such wells are located along the shore in close proximity to the 

Sound. Two wells at Saybrook Point are reported to contain fresh 

water except during dry seasons, when the water becomes low and 

brackish.

463 IRR 232 09 10
146 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

WATER LEVEL.

The wells in till have an average depth of 24 feet and those in 

stratified drift 48.3 feet so far as recorded. The average depth to 

water in these wells, however, is 10 feet for the till and 20.6 feet for 

the stratified drift. If the thousands of unrecorded wells in the State 

were added to the list the average distance of water from the surface would probably be still less. These figures indicate the freedom 

of circulation of water, especially in the stratified drift, for the principal water horizon is at a depth of 35.5 feet and the average rise of 

water in the well is therefore 15 feet. Unlike the wells in sandstone 

and crystalline rocks, the wells in till and stratified drift are subject 

to great variation of water level, both annual and seasonal, and 

sometimes daily.

The average variation of water level of wells in till recorded on 

pages 148-150 is 12 feet, sufficient to render many shallow wells 

valueless in dry seasons. Most of these wells have a regular annual 

period of maximum supply in late winter or spring, when they are 

full or overflowing. Single showers often raise the water level because 

of the added supply, but much more because of pressure on the air 

contained in the soil. Sudden rises of water in wells amounting to 

several feet are frequently reported, under circumstances where the 

rainfall could not have had time to enter the well through the drift 

and where the pressure of soil air was amply sufficient to account 

for the phenomenon. However, it is usually impossible to tell in 

any particular case, how much of the rise is due to infiltration and 

how much to the pressure applied to the air occupying the space 

between the grains. The wells of Sperry & Barnes, at New Haven, 

fluctuate in harmony with the level of water in the Sound, rising 

sometimes 10 inches in advance of the tide. The change in level is 

probably not due to the forcing of salt water toward the well, but 

rather to a squeezing of the fresh water from the pores of the sand, 

owing to the weight of the tons of water piled up on the shore.

In stratified drift the fluctuation of the water level is not so marked, 

owing doubtless to the greater ease of circulation in the loose-textured 

sands and gravels. Sudden rises, however, due to air pressure, as 

explained above, are reported.

The relation of rainfall to the fluctuation of water level in stratified 

drift is well shown by experiments conducted at the Yale Medical 

School, New Haven.0 The well in which measurements were taken 

is sunk in sand at 146 York street, and the rain gage was located on 

the roof of the Medical School building on the adjacent lot, and read 

on the 15th of each month. As shown by the table below, the greatest 

depth of water at any time was 7.15 feet and the least 5.50 feet, 

showing a variation during the year of 1.65 feet.

a Report Connecticut State Board of Health for 1889-90, p. 282.
WATER IN THE GLACIAL DRIFT. 147 

Rainfall and variations in ground water at New Haven, 1889-90.

Month.

December. .......................................... ..................

May....................................................................

July....................................................................

Rainfall.

Inches.

6.54

.87

3.96

2.87

7.13

3.64

4.36

5.23

4 91

57.84

Depth from 

surface to 

water.

Feet.

21.70

22

22.35

91 Oft

21.70

21.90

21.85

99 7ft

23

00 or

23

Depth of 

water.

Feet.

7.15

6.85

6.50

6

QK

7.15

6.95

7

6.15

5.85

S

en

K AK

5.85

COST OF WELLS.

Of 82 wells in stratified drift 28 are drilled, 22 are driven, and 32 

are dug. The average cost of 6-inch drilled wells is about $3.50 a 

foot; of 1^-inch driven wells, 70 cents a foot; and of 3-foot dug wells, 

$3.15 a foot.

Wells in till have an average inside diameter of 3 feet and an 

outside diameter of 6 feet. They are usually lined with field stone 

and cost an average of $3.10 a foot. -

RECORDS OF WELLS IN TILL.

The following table comprises the available records of Connecticut 

wells in till.
Records of wells in till in Connecticut. a

No.

*1

?,

3

*4

*5

*6

7

8

g

*in

11

1 o

13

15

16

17

IS

19

20

*?,1

?,3

94

?,6

*?,7

?,8

*?,9

30

01

QO

*33

QJ

OK

36

Q7

38

Town.

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

Locality.

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

.....do.............

Stanwich. .........

Owner.

E.D. White..........

W.F. Beach..........

G.C. Stone.. .........

A. T. Minor...........

F. H. Thompson......

C. M. Perry...........

H.B. Smith. ..:......

MissE. White........

.....do................

H.G. Clark...........

T. S. Brown. .........

L. H. Gofl. ...........

S.I>. West............

W. H. Wadhams......

H.G.Wright. ........

S.R. Close...... ......

Diameter.

Ftet.

7$

8

3

6

8

01

6

torn, 8.

Ql

3

2

°.i

01

10

4

3

4

6

3

bottom,4.

9 1

43

10

5

4

Depth.

Feet. 

17

24

7

16

1 9

23

27

23

27

18

18

16

94

30

QK

30

14

8

15

22

25

35

13

97

20

12

18

1 ^

1 ^

20

24

Depth to 

water 

level.

Feet. 

1-4

Var.

12

2

Var.

6+

3-20

6+

10+

6-10

2-8

5-16

4-10

30

5

Var.

5

10-16

6-24

5+

3-8

12

4 16

5

2-14

Var.

3-13

Var.

Quality

Hard...

.....do..

Soft....

.....do..

.....do..

.....do..

.....do..

Hard...

.....do..

.....do..

.....do..

.....do..

.....do..

.....do..

Hard...

Soft....

.....do.

.....do..

.....do..

.....do..

.....do..

.....do..

Hard...

.....do..

.....do..

Hard...

.....do..

Soft....

Hard..

Soft....

.....do..

Hard..

.....do..

Soft....
*39

40 

41

4?,

43

44

45 

46

47 

48 

«

ffi

51

CO

53

54 

*55

56 

57

58

59 

60

61

62

*63

64

65

66

67

68

69

70

71

7?

73

74

75

76

77

78

79

80

81

82

83

.....do.............

.....do.............

.....do.............

.....do............. 

.....do.............

.....do............. 

.....do............. 

.....do.............

.....do.............

.....do.............

.....do............. 

.....do.............

Litchfleld......... 

.....do.............

.....do.............

Madison........... 

.....do.............

.....do.............

.....do.............

.....do............

Milford. ...........

.....do............

.....do............

Old Mystic........

.....do............

.....do............

Washington.......

.....do.............

Hebron ...........

.....do............. 

.....do............. 

.....do.............

Shelton...........

.....do.............

.....do............. 

.....do..............

Prospect .......... 

.....do.............

.....do.............

PendletonHill....

Old Mystic........

.....do. ...........

.....do............

Washington Det>ot

S. G. Fish............

C. R. Heath........... 

E. P. Arnold..........

B.W.Kelsey. ........

E. E. Lewis...........

F. W. Little..........

R. D. Stephens....... 

Edw. T. Smith........

A. E. Hewitt..........

O. J. Beard........ ...

J.H.King............

H.S. Clark.. .......... 

H. N. Pavne..........

M. T. Bushnell........ 

J. Q.Buell... .........

P. P.Coe. ............

S. H. Chittenden......

D.L. Clark...........

E. C.Hildebrand.....

L.C.Morris...........

A. H. Hill... .........

H.V. Baker..........

S. H. Babcock........

J. B. Cornwall.........

Mrs. E. C. Schwab....

C.H. Welles..........

W.H. Smith..........

E. C. Whitehead......

Outside, 8;

inside covering, 3. 

2J 

9

3

3

4 

4

"4 

5

21 

3

3

2J 

6

3

6

3 

3

3

3

3

3

qi

3

3

3

91

W

5

6

W 3

3

4

<»)

(»)

3

6

3

16

?0

8

14

15

?0

35

18

28

15

67*

?5

14

20

19

?8

17

22

?4

23

19

97

15

21

27

30

14

38

19

8

75

30

17

14

36

25

20

16

50

52

3?

14

IS

3-13

3-17

0

0

6

10-19

15^20

12

60

0-19

9-14

12

5

3

10+

8

6

Var.

16

3-11

12-22

8-13

10-20

10

10+

4-19

3

2-15

-5-15

6

12

8

8

40

48

7-20

7

4-10

Hard..

.....do..

.....do..

Soft....

Hard...

Soft....

Soft....

.....do..

.....do..

.....do..

.....do..

Hard...

Soft. ....

.....do..

Hard...

Soft....

Hard...

.....do..

.....do..

Soft....

.....do..

.....do..

Hard...

.....do..

.....do..

Soft....

.....do..

Hard...

.....do..

.....do..

Soft....

.....do..

Hard...

.....do..

Soft....

Hard...

.....do..

.....do..

.....do..

.....do..

Additional details concerning wells marked with an * are given on p. 151. 
Records of wells in till in Connecticut Contin

No.

84

85

86

87

88

89

Qn

91

9?

93

94

Q>;

9fi

Town.

.....do............

.....do............

.....do............

.....do............

.....do............

.....do............

.....do............

.....do............

Locality.

Wilton. ...........

.....do............

.....do............

.....do............

.....do............

.....do............

.....do............

.....do............

Owner.

A. L. Burdick.........

J. Gilbert. ............

W.T.Jelliffe.. ........

Mrs. P.P. Gilbert.....

N. H. Bloss...........

Diameter.

Feet.

3

4

3

3

10

01

3*

6

3

4

4

Depth.

Feet. 

22

18

20

25

1 20

21

17

20

32

12

40

30

12

Depth to 

water 

level.

Feet. 

21

7

Var.

10

4-19

6-8

14

10-20

3

2

Quality

.....do..

.....do..

.....do..

Hard....

Soft. ....

.....do..

Soft.....
WATEK IK THE GLACIAL DEIFT. 151

NOTES.

1. Passes through 3 feet of moist clay loam above 14 feet of hardpan. This is 

one of six dug wells varying from 16 to 28 feet in depth, and is stoned, jug shape.

4. An excavated spring, the water being transported by a pipe with a 50-foot 

fall.

5. Passed through hardpan for the entire depth. The water level varies greatly, 

the well being nearly dry in some seasons. A stream the size of a lead pencil was 

struck 6 feet from the top and another stream was encountered below a flat rock.

6. In hardpan, with loam above. Water flows into the well from the northwest.

10. Supply said to be practically unlimited and lowered with difficulty. Well is 

in sandy clay underlain by hardpan.

21. Put down in 1900 through 14 feet of hardpan and obtained a strong flow from 

quicksand.

27. Passed through 3 feet of soil and 22 feet of "clay hardpan" containing "stones 

as large as a water pail." No streams of water were encountered, the water oozing 

from the hardpan in drops.

29. Blasted into rock 5 feet and occasionally becomes dry; 35 feet away is an 

unfailing well sunk 7 feet in till and containing soft water.

33. Never failing, but varies in amount of water with seasonal changes. Passes 

through 3 feet of loam and 15 feet of hardpan.

39. Passed through 2 feet of topsoil, 8 feet of clay subsoil or hardpan, and 6 feet 

of sand and gravel. Water came in from several small veins (probably from sand 

and gravel). Water level lowers in dry seasons, but ordinarily rises within 8 feet of 

surface.

43. Flows in wet seasons and occasionally runs dry at the same time as an adjacent stream. The well is located on a sandy knoll, and may be in stratified drift.

55. First 5 feet were soil and clay subsoil; first water struck at 9 feet, yielding 40 

barrels a day. Remaining 19 feet through hardpan containing and underlain by 

coarse gravel at the bottom, from which issued a large stream of water rising within 3 

feet of the surface. According to Rev. R. E. Turner, local artesian conditions prevail.

63. Struck water at 13 feet below the surface, where rocks occurred in sand and 

water came in as a strong flow. Has never been dry.

RECORDS OF WELLS IN STRATIFIED DRIFT.

The available records of wells in stratified drift are summarized in 

the following table:
Records of wells in stratified drift in Connec

No.

1

5

6

7

8

*9

10

11

1?

13

14

15

16

17

18

1Q

*?i

22

Town.

.....do........

.....do........

.....do........

.....do........

.....do........

.....do........

Fairfleld.......

Locality.

.....do........

Berlin. ........

.....do........

.....do........

Palls Village...

South Coventry.

.....do........

.....do........

Greenfleld Hill

Owner.

Thos. Sullivan...

Y.M.C. A......

H. J. Smith.....

J. P.Neville.....

E. J. Clark......

C. W.Hollister..

J. W. Nichols....

Church of the Sacred Heart.

Mrs. M. Colburn.

F. K. Hallock...

sonia Brewing 

Co.

F.L.Ray.......

F.A.King......

A. P. Carroll....

Type.

Drilled...

Dug......

...do.....

Dug......

...do.....

...do.....

...do.....

...do.....

Dug......

...do.....

Drilled...

Dug......

Drilled...

Dug......

...do.....

...do.....

...do.....

Dug......

Topographic 

position.

Valley....

Valley....

bed.

Hill......

...do.....

Hill......

Ridge....

...do.....

Hill......

Plain.....

coast. 

Hill......

Diameter.

In. 

5

so

on

2

36

36

36

36

6

30

6

6

6

30

48

3fi

U

2

36

Depth.

Feet. 

63

6

84

26

10

16

qc

44

17

48

17

12

45

Af\

84

155

30

28

22

16

AQ

Depth 

to 

principal 

source.

Feet. 

50

8

11

4

3&-44

15

48

17

35

on

00

20

Depth 

to 

water 

level.

Feet. 

45

1

2

14

5

11

12

2

24

24

OO

2

winter.

Yi

p

min

Ga

Go

»

Lar

Go

Go

Go

Sm
23

24

25 

26

27

28 

29 

30

31 

32

33

34

35

36

37

38 

39

40 

41

42 

43

44

45 

46 

"47

48

"49 

"50

* do

Farmington...

Glastonbury... 

.....do........

Guilford.......

.....do........

.....do.. ...... 

Killingly......

.....do........

Milford........

.....do........

.....do........

.....do........

.....do........

.....do........

New Haven . . . 

.....do........ 

.....do........

.....do........

.....do........

.....do........

Farmington. . .

Buckingham . . 

.....do........

Guilford.......

Mount Cannel. 

.....do........

Danielsonville.

Attawaugan...

Gales Ferry v . . 

Mansfield 

Depot.

Woodmont.... 

Milford. .......

.....do........

.....do........

.....do........

.....do........

New Haven... 

.....do........ 

.....do........

.....do........

.....do........

.....do........

G. H. Bradley... 

Wm. Potts......

O. E. Bailey..... 

E.C. Weir......

Glasgo Yarn 

Mills. 

C. Griswold .....

G. Parmelee..... 

County Orphans 

Home. 

A. E. Woodruff . Mount Cannel 

Bolt Co. 

Jas. M. Paine....

Attawaugan Co. . 

J. C. Hazier.....

C. Rogers & Bros.

A. G. Chapin.... 

B. B.B.Gregory.

Mrs. A.M. Coupland.

J. F. Schofleld. .

F. B. ShusterCo. 

.....do.......... 

Dining hall, Yale 

University. 

Hygienic Ice Co. .

Yale University 

gymnasium. 

Sperry & Barnes.

...do..... 

Drilled...

Dug...... 

...do.....

Drilled...

Dug...... 

...do.....

Drilled...

Dug...... 

Drilled...

Driven... 

Drilled...

...do.....

...do.....

Driven . . . 

Drilled...

...do..... 

...do.....

...do.....

...do.....

...do.....

...do..... 

Driven, 

9 wells. 

D riven, 

40 wells.

Driven, 

34 wells. 

Driven, 

40 wells.

mii ......

...do.....

Slope..... 

...do.....

Plain.....

Valley....

Slope.....

Plain..... 

Valley.... 

...do.....

Plain.....

'Fiat.'."."!."."

Plain..... 

...do.....

...do.....

40

48 

36

6

2 

40

6 

30

6

6

6 

6

6 

6

6 

6

6 

6

6

2 

2 

1,2

2 

2

w

78

7A

16 

93

65 

50 

21

50

35

42

12

33

75

47

35

35

92

70

40

32

78

58

7?,

-27

-70

71

42

18

24

8

""46"

118

80

65

29

25,60

39

28

51

25-27

20

8

Varies. 

26

"""46"

62

25

15

40

28

55

20

24

20

20

21

/ 20-25

Go

Go

Sm

Goo

Lar

Additional details concerning wells marked with an asterisk are given on p. 156.

6 Daily. «10,000 gal
Records of wells in stratified drift in Connecticut C

No.

51

5?,

53

54

55

56

57

58

59

fin

fil

6?

63

*fi4

65

*66

67

68

69

*70

*71

7?,

*73

74

75

Town.

.....do........

.....do........

Old Mystic....

Old Saybrook .

.....do........

.....do........

Plainfleld.....

.....do.........

Pomfret.......

Ridgefield.....

Seymour......

Union. ........

.....do.........

.....do.........

.....do.........

Locality.

.....do........

Old Mystic....

Point. 

.....do........

.....do........

Ridgefleld.....

Seymour ......

Baltic.........

Stafford

Springs.

.....do.........

Owner.

.-...do..........

C. L. Mitchell...

Jas. H. Webb...

R.&G. Corset Co

provement Co.

A. A. Haley.....

C. E. Jackson. . .

J. T. Beckwith..

W.G.Bulkeley..

Ridgefleld Water

Supply Co.

Baltic Mills Co...

.....do...........

G. W. Crawford.

N. B.Mead......

Mrs. F. B. Wood.

Type.

...do.....

Dug. .....

Drilled...

Dug......

Drilled...

...do.....

Dug......

...do.....

...do.....

Drilled...

...do......

Dug. .....

Drilled, 5

wells. 

Drilled...

...do......

...do......

...do......

Dug......

Drilled...

drilled.

Topographic 

position.

Valley . . .

...do.....

Plain.....

Valley....

Plain.....

Valley....

Plain.....

Valley....

Hill......

Plain.....

...do......

...do......

Diameter.

In. 

2

2

36

U

8

36

6

6

36

30

6

72

6

6

6

11

2

2

36

6

Depth.

Feet. 

70

80

22

20

1 JO

20

10

50

31

17

20

100

fin

no

101

qc

33

38

15

110

53

Depth 

to 

principal 

source.

Feet.

12

83

60

35

43

Depth 

to 

water 

level.

Feet. 

12

12

10-20

10

M

8

7

6

20

10

OK

Var.

50

23

40

20

9n

9

30

42

Yie

j>e

minu

Gal

Goo
77

7Q

79

80

*81

#89

.....do.........

Willington....

.....do.........

South Willington.

.....do.........

Mrs. E. W. Talcott.

Co.

M. A.Hurd.....

L. J. Alien......

Drilled...

Drilled...

Dug......

...do......

...do......

...do......

Hill......

Plain.....

Valley....

...do......

U

6

180

48

36

24

9flfl

20

51

15

90

20

31

26

4-fl

12

on

13

<»

a Per foot. 6150
156 TJNDEKGKOTJND WATBE RESOUKCES OF CONNECTICUT.

NOTES.

9. Dug in a springy spot, water being struck almost immediately, with a heavy 

flow &i the bottom. Level varies somewhat with seasonal changes, but even in dry 

seasons is high.

20. Log shows coarse sand containing much water, beneath which is fine sand, 

underlain by 6 inches of gravel, and clay at the bottom.

21. First 12 feet through gravel, which overlies 50 feet of quicksand that plugged 

the pipe and prevented inflow. The water horizon is in gravel below the quicksand.

47. Used for condensing ammonia in refrigerator. At 26 or 27 feet below surface is 

quicksand and below this clay.

49. Located near together and used to supply water for baths and swimming pool.

50. Driven in at sea level; water rises 10 inches in advance of the tide. The pipes, 

40 in number, pass through 7 feet of tide water, 25 feet of soft blue mud, 6 feet of hard 

blue clay, 3 feet of material resembling hardpan, and 2 feet of mixed coarse and fine 

gravel, which yields the water. A pipe has been sunk 300 feet from the surface, 

passing through quicksand all the way below the gravel to bed rock.

64. Sunk through 5 feet of black and yellow loam and 16 feet of dark-colored hardpan with cobblestones, reaching rock here at 25 feet below the surface. One-half 

mile farther north is a second well, 15 feet deep, which passes through soft loam and 

quicksand and yields an abundance of soft water. Immediately to the east are wells, 

10 to 12 feet deep, in gravelly soil. Toward the south the wells are in clay and hardpan.

66. One of a gang of five driven wells (two 6-inch and three 3-inch) supplying the 

town of Ridgefield. Another 6-inch well is 75 feet deep but of small yield, probably 

because it passes nearly through the water-bearing gravel.

70. Driven wells on gravel island in small lake. Temperature of water said to be 

48° to 52° from February 15 to July, and from July to February will rise to 58° to 62°.

71. Said to have been drilled through hardpan, the water coming in several small 

veins.

73. Passes through thin layers of loam and gravel and at 12 feet into "closely 

packed broken rock."

76. Drilled 19 feet into rock, but the supply of water comes at the contact of the 

rock and the surface material.

81, 82. Said to have passed through sand, gravel, and clay, deriving their water 

from clay. A complete record of a well in the same vicinity gives 15 feet solid clay; 

15 feet hardpan containing pebbles one-half inch to 3 inches in diameter; 41 feet 

gravelly dark soil; 29 feet bowlder material; 10 feet decomposed dry rock.
CHAPTER VII. 

WATER SUPPLY OF TYPICAL AREAS.

WARREN A HIGHLAND TOWN.

Warren is a typical highland town, with a population of 432, devoted to agriculture and allied interests. It has an average elevation of about 1,000 feet and an annual rainfall of about 50 inches. 

Mica schist (Berkshire) forms the bed rock in the western and southeastern parts of the town; gray banded gneiss (Becket) occurs at 

Cornwall Center; and granite occupies the northeast corner of the 

town on both sides of the west branch of the Shepaug. Glacial till 

forms a mantle over most of the rock surface and constitutes the 

principal water-bearing formation.

There are very few places in the town where abundant water is not 

found at a depth of less than 40 feet, and springs are numerous at 

low and high levels. In general, the farmers can choose between 

digging a shallow well and bringing water from a spring, as the cost 

of digging a 30-foot well is estimated to be the same as installing a 

pipe line 80 rods long. Mineral springs are not found in the town, 

and only one windmill is reported. The springs furnish soft water, 

the wells hard.

The following detailed information regarding the water supply of 

Warren has been furnished by Myron A. Munson. The numbers 

refer to locations on the accompanying map (fig. 27).

1. Spring sunk 4 feet, near the house; go for the water.

2. Water for house and barn brought from spring 50 or 60 rods east; soft, and excellent; running since 1852. Also well 14 J feet deep, water 7 feet; poor, apparently 

surface water mainly.

3. Water obtained from spring.

4. Well 16f feet deep; water 5 feet; good.

5. Well 21 feet deep; water 8| feet; excellent, "soft for a well, makes good suds."

8. Well 15J feet deep; water 7 feet; rather hard; use rain water also.

9. Well 19 feet deep; water very hard. There are two excellent springs at a distance of 20 and 30 rods.

10. Conditions not favorable for wells.

13. Three wells on the place. The one now in use is less than 20 feet deep. Water 

was formerly soft; coal ashes were deposited in some near-by depression, since which 

the quality of the water has deteriorated. The well is unfailing, and the supply so 

copious that it is difficult to exhaust the well sufficiently to prepare it for cleaning. 

"It would supply water for a hundred cattle." There are two springs on the place 

with water having a temperature of 48°.

157
158 UNDEEGEOUND WATBE EBSOUECBS OF CONNECTICUT.

14. Well about 12 feet deep; water is soft.

17. Water conducted from a spring.

18. Water brought from a spring on a lower level by means of a ram.

19. Water brought to house from spring, which is about 25 feet above the doorstep 

and 15 rods distant; 2 feet deep; fails in dry season. A second spring, supplying 

water to barn, boils up through sand and never fails; water is conducted to south 

barn. A third spring, of constant flow, supplies milk house and horse trough. A

- _ __ CORNWALL

W A S H I N <J X 0_N

FIGURE 27. Map of Warren, showing location of wells.

fourth spring, unfailing, is used only as pasture supply. Across the swampy meadow 

to the west is another good spring.

20. Rock ledge exposed; water formerly conducted from a spring. Conditions at 

the house are unfavorable for wells.

21. Well 18 feet deep; water 5J feet; not very hard; two springs across the road 

supply milk houses.

22. Well 12 feet deep; water very hard. Spring at milk house across the road is 

declared to be "soft and sweet."
WATER SUPPLY OF TYPICAL AREAS. 159

23. Well 19J feet deep; water hard; rain water also used. Spring at milk house 

consists of three streams, which gush up from sand.

24. Obtains water from a spring in the field.

25. Supply similar to No. 24.

26. Has a "laundry spring" within 3 or 4 rods of the house; a better one 5 or 6 rods 

away; soft, and seldom failing.

27. Well 12 feet deep; water hard; rain water also used.

28. A good spring of soft water 5 or 6 rods distant from the house, "flowing as fast 

as can dip;" another colder spring is 4 rods farther away.

29. Well 38 feet deep; water 22J feet; hard, and unfailing. At 50 rods down the 

hill to the northeast is an ice pond into which five springs flow. An unsuccessful 

attempt was made to bring an unfailing spring from a distance of a quarter of a mile. 

A windmill was installed at the well a few years ago but was later discarded.

30. Well 18 feet deep; water 9£ feet.

31. Well 16 feet deep; water 6£ feet. Soft water is brought from a spring 30 rods 

distant.

32. Brings water in pails from an excellent spring of soft water at a distance of 8 

or 10 rods.

33. This family obtains water from a good spring 30 rods distant.

35. Water rather hard.

36. Well 17| feet deep; water very hard, also contaminated. A new well about 12 

feet deep at a distance of 15 rods obtained good water.

37. Well good; unfailing in driest times.

39. Well 13^ feet deep; water hard, yet suitable for washing.

41. Well 16J feet deep; water said to be good.

42. Well 23J feet deep; water a little hard. Used for all purposes, though a little 

way east and west of the house are two soft springs. Is the "best in town." Never 

known to fail when drought was most severe.

43. Well 17 feet deep; water 7J feet; a little hard; rain water (cistern) also used. 

Excellent spring 70 rods to the northeast in corner of the orchard; another 150 rods to 

the southeast. Horse barn supplied from a well 10 feet deep, containing 6J feet of 

water. "The springs about here are soft."

44. Water carried from a spring near at hand, but at a lower level.

45. Well 15J feet deep; water 6 feet; good. A spring in a swamp near at hand has 

been used.

46. Well 7 or 8 rods west of house, 15 J feet deep; contains 7J feet of poor water. 

Water has been carried from the swamp named above (No. 45) into the cellar 'of this 

house, but the method worked poorly, and frequent repairing was necessary.

47. Water conducted from a spring at a considerable distance.

49. Water from spring at a distance of 40 rods.

50. Well 5 feet deep; water hard; unfailing.

51. Water brought from a spring sunk to produce a well of 12 feet depth; soft, good, 

and unfailing; has been used for fifty years.

52. 53. Two of six houses supplied from a spring on the hills to the east. 

54. Unfavorable location for wells. Well measures 36J feet, the "deepest in the 

town;" water 13 feet, but is " likely to become scant in the summer."

56. Well 20^ feet deep; water has an iron taste. A well 13J feet deep across the 

road in a corner of the barnyard is said to contain good water.

57. Well a few yards west of the house 16J feet deep; water very hard. A number 

of good springs on lower ground.

58. Well 13J feet deep spoiled by drainage from cesspool. There are six good 

springs, sweet and soft, on the place at no great distance, four of the six never failing. 

The house is supplied by two springs united, a quarter of a mile distant. A ram is 

employed.
160 TJlSrDEKGKOTJND WATEK KESOUECES OP CONNECTICUT.

59. Well 17 feet deep; water 12| feet; "soft as a spring;" sometimes fails.

61. Well 12 feet deep; water 6 feet; unfailing; soft, good for washing. Said on 

the spot to be the "best in town."

62. Well 10 feet deep; water 5f feet, hard. Water is brought from a spring to this 

house and to the one across the road.

65. Spring of cold water issuing from a beautiful grotto; water is of uniform temperature throughout the year.

NORTH HAVEN A LOWLAND TOWN.

The conditions surrounding the occurrence and recovery of ground 

water in the central lowland are illustrated in the town of North 

Haven, a portion of which is shown on the accompanying map (fig. 

28). The area has an elevation of less than 100 feet and is underlain 

by sandstone, on top of which rest clays, sands, gravels, and till of 

glacial origin. Sand with large water capacity is the predominating 

surface formation. In the following descriptions the numbers refer 

to locations on the map:

1. Well 30 feet deep; contains about 4 feet of water. In sand and gravel the entire 

distance. , 2. Well 30 feet deep; has 6 feet of water. In sand and gravel.

3. Well 30 feet deep, in sand and gravel; has 4 feet of water, "not very good."

4. A drilled well, 115 feet deep, all of the distance in sand and gravel.

5. Well 20 feet deep; has 4 feet of water. In sand and gravel.

6. .One well 30 feet deep, with 5 feet of water; one 20 feet deep, with 6 feet of water; 

both in sand and gravel. There is also an excellent spring at this place, having a fall 

of 11 feet, which is sufficient to force water to all parts of the house. The ground 

water in the spring and in the shallow well appears to come from the northwest; that 

in the other well comes from the northeast.

7. Passes through sand, reaching rock at a depth of 20 feet. The water comes from 

just above the rock. The well is practically inexhaustible, three families using it all 

the time.

8. A large supply of good water from a well sunk 17 feet into sand. Has 7 feet of 

water.

9. Drilled in sandstone to a depth of 153 feet. Most of the water was reached at 

the 50-foot level.

10. One well is 16 feet deep in red sandstone and near at hand is another well or 

spring 9 feet deep in which the water is seen to bubble up through the sand at the 

bottom. One hundred barrels of water have been pumped from this spring at one 

time without exhausting the supply. Both wells are very close to 'Quinnipiac River.

11. Drilled well 45 feet deep; in rock for almost the entire distance. Gives an 

abundant supply of good water.

12. Drilled in red sandstone to a depth of 126 feet, most of the water being reached 

at a depth of about 45 feet; yields a good supply of water. A spring also occurs in the 

back yard.

13. Well 25 feet deep; walled with stone. After every freshet the sand pours in at 

the crevices so that it needs cleaning frequently. The water is excellent and abundant.

14. Well 15 feet deep; contains 5 feet of water. It does not fail, and the water is 

soft and good.

15. Well 16 feet deep; holds 8 feet of water. The water is very good, but fails in dry 

seasons. Spring 300 yards to the northeast gives an abundance of water for house use 

and is high enough to send water into all the rooms of the second story by gravity. 

There is also a spring at the barn.
WATEK SUPPLY OF TYPICAL AEEAS. 161

16. Constant spring of good water.

17. Said to be about 20 feet deep.

18. Well 17 feet deep. The first few feet are in sand and the remainder in red 

sandstone, with a sharp easterly dip. The water occurs in the rock and varies but 

little with the seasons.

19. Well 22 feet deep; has about 4 feet of soft water.

20. Well 30 feet deep, the last 18 feet in red sandstone. The water found in the 

rock is soft and plentiful.

21. Well 30 feet deep, in sand and gravel. About 5 feet of soft water stands constantly in the well.

'/a Mile

FIGURE 28. Map of North Haven, showing location of wells.

22. Well sunk 35 feet in sand. Water is plentiful and not very hard.

23. Two wells; one at barn 25 feet deep with 3 feet of water; one at house 30 feet 

deep with 5 feet of water. Neither well runs dry.

24. Well 30 feet deep; has 5 feet of water. The first 25 feet are said to be in hardpan 

and the remainder in sand. Abundant water was found in the sand.

25. Well 30 feet deep. The first 25 feet are in the hardpan, then comes 2 inches 

of sand in which the water is found, and then about 4 feet more of hardpan. The 

water is plentiful, varies from 3 to 11 feet in depth, and is soft enough to be used continually for a laundry.

463 IRE 232 09 11
162 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

26. Drilled well 128 feet deep. It is reported that the first 84 feet are in sand and 

hard gravel and the last 44 feet in hardpan.

27. Drilled well 140 feet deep; derives water at depth of 100 feet, near contact of 

rock and till. Water is hard, rises within 25 feet of the surface, and does not vary in 

amount with seasons.

28. Well dug in hardpan to a depth of 44 feet. In the spring it sometimes contains 

as much as 15 feet of water. '' This water will rust a tin in one night.''

29. A very old well, dug and walled with brick; 45 feet deep; amount of water 

varies from 5 to 15 feet.

30. Dug well, 29 feet deep; contains 4 feet of water.

31. Dug to a depth of 45 feet in course gravel. Became dry during one season.

32. Dug to a depth of 12 feet in sand and gravel. It was dry once, but only for a 

short time. Ordinarily about 2 feet of water stands in the well.

33. Family gets water from a spring which issues at the top of a layer of clay.

34. Well 15 feet deep; has 2 feet of water. Walled with brick, but abandoned on 

account of surface contamination.

35. Drilled well, 195 feet deep; yields 8 or 10 gallons a minute. The first few feet 

are in sand, then comes about 50 feet of clay underlain by red sandstone. There are 

several recently drilled wells in this neighborhood, and their use has been followed 

by a great decrease in the number of cases of malaria.

36. Water for drinking purposes is brought from a spring which emerges at the contact of sand and clay.

37. Dug through sand and strikes a clay stratum at 13 feet.

38. Dug to a depth of 15 feet 6 inches, where it strikes sandstone; contains 7 feet of 

water and does not fail.

39. Dug in rock to a depth of 15 feet; contains about 7 feet of water.

40. Well on the hill is dug to a depth of "about 50 feet," the last 40 feet being in 

sandstone. At this same locality a shallow rock spring with insufficient water waa 

converted into a satisfactory supply by drilling 10 feet into the rock.

41. Dug well 7 feet deep, the last 4 feet in red sandstone. The ground water is seen 

to come from the northwest.

42. Well at barn dug to a depth of 13 feet 6 inches, in sand and gravel; yields 

hard water. Well at house, in the cellar, is about 15 feet deep; passes through gravel 

to hardpan, where an abundant supply of soft water is procured.

43. Conditions same as at No. 42.

44. Drilled well in sandstone with a depth of "over 100 feet."

VICINITY OF BRANFORD POINT A COAST REGION.

The region about Branford Point is fairly typical of the coast 

resorts along the Connecticut shore. It includes rocky knolls, 

stretches of sand flats and beaches, and expanses of marsh land. 

The bed rock of this area is gneiss, much broken by joints and 

planes of parting. The soil cover is till and beach sands. The 

insufficiency of supply and the danger of contamination by salt 

water have made it advisable to conduct water by pipe line from 

Branford River and to make this the chief supply. Two small 

springs are reported from this area.

The following descriptions accompanying the map (fig. 29) give 

detailed information regarding conditions which are typical of the 

water at Connecticut resorts.

1. Well 25 feet deep; contains about 5 feet of water, which is soft enough to make 

good suds.
WATER SUPPLY OF TYPICAL AEEAS. 163

2. Well has constant supply, medium in softness. It is 23 feet deep and contains 5 feet of water.

3. Well 24 feet deep; contains about 4 feet of water of medium softness.

4. Same depth and character as No. 3.

5. Well 27 feet deep; contains 3 feet of water.

6. One of the wells at this place is situated 5 feet from the edge of a salt marsh, 

but has never been known to become brackish. It is a driven well to a depth of 14 

feet and contains 4 feet of water. The other well is sunk through glacial till, is 22 

feet deep, and derives water from the contact of rock and till.

FIGTJKE 29. Map of vicinity of Branford Point, showing location of wells.

7. A permanent well with water of medium softness; 32 feet deep; contains 4 feet 

of water.

8. Water said to be harder than in the other wells of the vicinity. The depth of 

the well is 33 feet and the water stands at 29 feet.

9. Well of hard water, 33 feet deep.

10. Dug to a depth of 25 feet; contains 4 feet of hard water.

11. Well 25 feet deep; has 4 feet of hard water; has never been known to fail.

12. Well 25 feet deep; has 4 feet of water.

13. Although situated very near the salt marsh and the tidal river, this well contains good water. It is 26 feet deep and has 3 feet of water. It has never failed.
164 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

14. This place is supplied by a well driven 5 feet below the cellar floor. Fresh 

water enters "like a spring" at the edge of the marsh.

15. This factory is located mostly on "made land" recovered from a salt meadow. 

Wells were brackish and were accordingly abandoned.

16. Well 12 feet deep; contains 1 foot 6 inches of water. Water became brackish 

and has been discarded in favor of city water.

17. Well 23 feet deep; contains a constant supply of about 3 feet of hard water.

18. Well 25 feet deep; contains 2 feet of hard water.

19. Well 25 feet deep; has 3 feet of soft water; yield regular.

20. Well 22 feet deep; has 3 feet of hard water.

21. Well at barn 15 feet deep; contains about 4 feet of water. City water used at 

house.

22. Well sunk in rock much broken by joints which permit access of salt water.

23. Well 25 feet deep; contains 2 feet 6 inches of water which is little affected by 

dry weather. Water is claimed to be soft and palatable.

24. Rain water is used because wells give brackish water.

25. Two driven wells in house, each 24 feet deep. One of these wells has yielded 

a good supply of soft water for twenty years.

26. On a narrow neck of land between two salt marshes and not over 20 feet from 

one of them; 16 feet deep; contains 3 feet of hard water.

27. Well 17 feet deep; contains 3 feet of water, which is wholesome but a little 

hard.

28. Well 23 feet deep; contains a constant supply of hard water.

29. Water is medium in softness. Well 25 feet deep, with 3 feet of water, and does 

not fail.

30. Well 22 feet deep; contains 2 feet of water of an unsatisfactory quality.

31. Well 24 feet deep; contains 3 feet-of water of medium softness.

32. Well 25 feet deep; contains 4 feet of soft, wholesome water.

33. Well 16 feet deep, with 5 feet of water of good quality.
CHAPTER VIII. 

CHARACTER OF GROUND WATER OF CONNECTICUT.

INTRODUCTION.

Pure water, as a compound of hydrogen and oxygen, is not known 

in nature. Descending rains take from the atmosphere considerable 

of its impurities and carry them to the ground; carbonic acid, sulphates and nitrates, especially near cities where coal is used for fuel, 

sodium chloride in the vicinity of the sea, and atmospheric dust contribute to the rainfall. Of the common gases rain water contains 

about 25 cubic centimeters per cubic meter, consisting of nitrogen 

about 64 per cent, oxygen 34 per cent, and carbonic acid 2 per cent. 

With the exception of chlorine, however, all the impurities of the air 

may be disregarded in the study of ground water.

After water enters the soil, it gathers materials from rocks and 

from decomposing organic matter. Sodium and potassium are taken 

from rocks containing feldspars. Calcium and magnesium are extracted from limestones and in less degree from rocks of other types. 

The minerals taken up by water in its subterranean course are chiefly 

silica, iron, aluminum, calcium, magnesium, sodium, potassium, 

chlorine, organic acids of uncertain composition, and the carbonate, 

bicarbonate, sulphate, and nitrate radicles. Barium, strontium, 

lithium, and other elements occur less commonly in appreciable 

quantity. Free carbonic acid gas is an ordinary ingredient of natural 

water, and oxygen, hydrogen, nitrogen, hydrogen sulphide, and 

hydrogen phosphide in solution are occasionally encountered.

As the value of water for any given purpose is determined by its 

composition, chemical study of surface and ground waters becomes a 

matter of great practical importance. The composition of ground 

water in Connecticut is of prime interest, because only the larger 

cities within the State receive their water supply from brooks or 

lakes. Of the 168 towns in the State 140 depend entirely on wells 

and local springs for their water supplies, and it is estimated that 40 

per cent of the population obtain water for domestic purposes from

more than 90,000 wells and springs.

165
166 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

COMPOSITION. 

DETERMINING CHARACTERS.

The composition of the ground waters within the State is determined by the character of rock from which they are drawn. Shallow 

wells and springs in glacial drift contain substances leached from the 

upper soil and include nominal amounts of chlorine, sulphates, carbonates, nitrates, silica, calcium, magnesium, potassium, and sodium, 

with iron and aluminum in small amount, and a relative absence of 

organic matter. The deeper wells in the drift contain the same substances, but larger amounts of iron and less nitrates. Waters from 

glacial till and from rock are characterized by their relatively high 

content of calcium, magnesium, and sulphates. This is particularly 

true of water from sandstone and closely packed till or hardpan.

HARD AND SOFT WATERS.

As water takes up chemical compounds during its percolation 

through the ground, it often becomes what is commonly known as 

"hard" water, the term indicating its ability to form insoluble calcium and magnesium soaps when used for washing purposes. The 

greater proportion of the mineral constituents dissolved in shallow 

ground waters is obtained near the surface in what is known as the 

belt of weathering. This is the unsaturated zone between the ground 

surface and the level of the water table. The mineral constituents 

of this belt are relatively insoluble in their natural state, but they 

are continually undergoing oxidation, hydration, and carbonation, 

which result in the formation of compounds soluble in water. In 

the upper portion of the soil there is a large amount of organic 

matter which is oxidized through natural decay to carbonic and 

other acids. These acids, dissolved in water, attack the rocks and 

increase the mineralization of the underground supply. Calcium and 

magnesium in equilibrium with the bicarbonate radicle in water 

constitute temporary hardness, so-called because the minerals may 

be removed by boiling the water. If, however, the sulphate rather 

than the bicarbonate radicle is present the water is said to be permanently hard because boiling will not remove the dissolved minerals. The amount of calcium and magnesium present determine 

the relative hardness of water, and the proportions of the bicarbonate and sulphate radicles determine its character. The oxidation 

of iron sulphide is probably a source of sulphuric acid, which may 

decompose rocks with which it comes into contact. Among the 

most common constituents of crystalline rocks are silicates of iron, 

aluminum, calcium, and magnesium. These silicates in themselves 

are practically insoluble in water at ordinary temperatures, but in
CHARACTER OF GROUND WATER. 167

the presence of waters containing carbon dioxide they are subjected 

to chemical changes and are carried away in solution.

There are many other methods by which water obtains mineral 

matter in solution, but those cited above are sufficient to illustrate 

the processes. It has been estimated by Reade 0 that for the entire 

earth there is removed annually in solution 96 tons of material per 

square mile, consisting of calcium carbonate, 50 tons; calcium sulphate, 20 tons; sodium chloride, 8 tons; silica, 7 tons; alkaline carbonates and sulphates, 6 tons; magnesium carbonate, 4 tons; oxide 

of iron, 1 ton.

MATERIAL TAKEN INTO SOLUTION.

Although there are many factors determining the character and 

the amount of the materials taken into solution by underground 

water, only two need be considered in this discussion. They are 

the character of the material traversed by the water, and the distance which the water has traveled underground. The waters of the 

glacial drift exhibit great variability of composition and are almost 

equally divided between hard and soft waters. In general the waters 

from the finely divided clay till are hard and those from the sand 

and gravel deposits are soft, owing to the character of the material. 

The sand and gravel deposits are composed largely of coarse grains 

of quartzose materials, which are dissolved with great difficulty by 

water, but the till is made up in part of masses of finely divided 

heterogeneous material which not only offer a more varied assortment to be acted on by waters but also give greater opportunity for 

solution owing to their fineness of grain. The deep-well waters of 

the sandstone are much harder than those of the crystalline rocks. 

In the latter the crevices afford the only passage for the water, and 

consequently the solvent action of the water is largely confined to 

the immediate walls of the crevices. In sandstone, however, the 

water traverses the entire rock, passing not only through the seams 

but also through the small pores between the grains, and thus has 

a vastly greater surface for action. Many of the sandstones of Connecticut are arkoses containing as great variety of mineral constituents as the original crystalline rocks.

In regard to the distance that the water travels, it is manifest 

that the longer and the slower the passage the greater opportunity 

there will be for solution. Increase of heat and pressure increases 

the solvent power of water; the waters which have penetrated deeply 

and have been subjected to great heat and pressure often have a 

larger proportion of dissolved minerals than those at shallow depths.

a Reade, T. Mellard, Chemical denudation in relation to geological time.
168 UNDEEGEOUND WATEE EESOURCES OP CONNECTICUT.

Analyses of waters from 13 wells in crystalline rock give an average 

of 132 parts per million of total solids. Analyses of 18 well waters 

derived from Triassic sandstone areas average 655 parts per million 

of solid matter. Exclusive of three well waters that contain over 

1,000 parts of solid matter, the average for 15 well waters from sandstone is 377 parts per million. Five well waters from glacial drift 

average 263 parts of mineral matter. The analyses of 25 spring 

waters give an average of 73.5 parts of total solids. It is impossible 

to state from the available data whether springs from one source contain more mineral matter than those from a different source. The 

information at hand gives no indication of any definite increase of 

mineral matter with increase in depth of the well, and though there 

might be such increase in very deep wells, it seems that within the 

ordinary limits of well depth in Connecticut between 100 and 500 

feet the relation of mineral content to depth has no practical 

bearing.

NORMAL DISTRIBUTION OF CHLORINE.

Chlorine, which is a constituent of common salt, is present in all 

natural waters and comes from salt deposits within the earth or from 

salt-laden spray from the ocean. In Connecticut there are no deposits of salt or other chlorine compounds from which waters might 

derive appreciable, amounts of chlorine, but this substance is present 

in them in considerable quantity and the proportion of it in ground 

water decreases regularly with increase of distance from the coast. 

The obvious inference is that the natural waters obtain their chlorine 

from the minute particles of sea water that are blown inland by the 

winds. The amount of chlorine in normal waters of Connecticut 

has been determined for different parts of the State,0 and a map prepared under the direction of Prof. H. E. Smith, of the Yale Medical 

School, indicates the normal distribution of chlorine by means of 

isochlors or lines defining the areas within which the waters in their 

natural state contain certain definite amounts of chlorine. (See 

PL V.) The value of knowledge regarding the normal distribution of 

chlorine is that it affords a ready basis for testing the purity of both 

surface and subterranean waters. Salt is present in all animal 

dejecta and eventually finds its way to the water courses, both above 

and below ground; consequently if a water contains more chlorine 

than the normal amount for the area in which it occurs, the presence 

of sewage or other contaminating matter may be suspected. Excess 

chlorine in wells immediately adjacent to salt water is not necessarily 

an indication of sewage contamination, but usually of the admixture 

of sea water.

a Kept. Connecticut State Board of Health for 1902, pp. 227-242.
U. 8. GEOLOGICAL SURVEY WATER-SUPPLY PAPER 232 PLATE V

MASSACHUSETTS

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normal or nearly so

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MAP OF CONNECTICUT, SHOWING DISTRIBUTION OF CHLORINE.
CHARACTER OF GROUND WATER. 169

USES OF WATER. 

WATER FOR DOMESTIC PURPOSES.

The uses to which underground water is ordinarily put in Connecticut are relatively few in number. Owing to the ease with which 

large amounts of soft water are obtained, city supplies are usually 

taken from ponded reservoirs-fed by surface drainage and by springs. 

For private residences and manufactories outside of cities, however, 

wells constitute the chief source of water supply for general purposes, 

and even in cities some manufacturing concerns find it expedient 

to use well water.

The three main purposes for which well and spring waters are used 

are for domestic supply, as in cooking, drinking, and washing, for 

boilers, and for coolers. A reasonably soft water is desirable for all 

these purposes and is particularly necessary in the case of boiler 

water, because hard waters form a scale in boilers, causing a heavy 

expense for additional fuel, cleaning of flues, extra firings, and boiler 

repairs. Soft water is preferable for general domestic use, though it 

is not so palatable as hard water. In breweries, distilleries, and 

other manufacturing establishments where a supply of cool water 

effects a great saving in artificial refrigeration, well waters are 

economical.

WATER FOR BOILERS.

Most of the large manufacturing establishments in Connecticut 

are on the banks of the more important streams, where abundant 

water for boilers may ordinarily be obtained from the heavy sand 

and gravel deposits that fill the major valleys. Such supplies are 

reasonably soft and cold and are satisfactory for cooling and boiler 

purposes, although frequently unsafe for drinking owing to surface 

contamination. Wells penetrating a considerable distance into 

the rock are preferable as sources of drinking water. Water from 

wells in the crystalline areas is usually soft enough for boiler use, but 

that in the sandstone areas is likely to be hard and is frequently disastrous to boilers. A study of Connecticut waters with regard to their 

availability for steaming purposes has been made by George H. 

Seyms, chemist of the Hartford Steam Boiler Inspection and Insurance Company, who has kindly allowed free use of his valuable data. 

Mr. Seyms has classified Connecticut waters in regard to their use in 

boilers, taking into account the average proportion of the different 

constituents in the normal waters of the State and assuming that 

one-half of the total solids is incrusting matter. Water containing 

less than 250 parts per million of solid matter is pronounced good. 

Water containing between 250 and 500 parts of solid matter is fair 

for boiler use, but if the amount exceeds 500 parts the water is unfit
170 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

for general boiler purposes. In making this estimate the fact has 

been taken into account that in most parts of the State supplies of 

soft surface waters may be obtained at reasonable rates. Increased 

hardness means increased cost of maintenance and where hard 

waters are used for boilers, as in the Western States, it is only because 

supplies of soft water are not available. The water supplies of Connecticut are recommended by Mr. Seyms for boiler purposes in the 

following order: (1) River waters (where uncontaminated by factory wastes); (2) ponded reservoirs; (3) small streams (as compared 

with rivers); (4) springs and shallow wells 30 to 50 feet deep; (5) deep 

wells. Wells in sandstone are less suitable as a source of water for 

boiler use than those in crystalline rocks.

CONTAMINATION.

INTRODUCTION.

That the ground water of Connecticut is liable to contamination 

and needs careful and frequent examination is well shown by the 

analyses of tainted waters made by the state board of health and by 

the typhoid epidemics which have occurred within the State. In 

1893 the health officers of 119 towns reported on the condition of 

water supply/ and pronounced the water of only 82 towns unqualifiedly good. In 1898 analyses were made of water from 247 wells on 

the premises of public schools in the State; only half of them were 

free from suspicion of dangerous contamination and many were 

highly polluted. 6 In 1899 only three out of 14 suspected wells examined were declared safe. 0 In 1902 the water supplies of 101 hotels 

and restaurants and summer resorts were inspected, and only 20 out 

of 33 samples taken from springs, wells, and cisterns were considered 

safe. d

Sixty cases of typhoid, probably caused by water from a well 25 

feet from a house, occurred in 1882 at Portland. 6 The drainage 

from a vault entering the quicksand caused typhoid at Guilford 

during the same yeary Water from a well in Middletown gave 

typhoid to an entire family in 1884.^ The analyses of water from 

three wells at Madison in 1885 revealed the source of pollution which 

caused 14 cases of fever. A Contaminated water at Money Island 

caused 21 cases of typhoid in 1891.* The epidemic at Stafford in 1894 

was traced to a polluted well.^ The great epidemic at Stamford in 

1895, in which 386 people were afflicted, was caused by milk delivered 

in cans which had been washed in well water infected by drainage 

from vaults. ^

a Ann. Rept. Connecticut State Board of d Idem, 1902, pp. 223-226. ft Idem, 1885, pp. 342-344.

Health, 1893, p. 110. e Idem, 1882, p. 140. - * Idem, 1891, pp. 205-213.

b Idem, 1898, pp. 279, 280. / Idem, 1882, p. 144. i Idem, 1894, pp. 232-238.

c Idem, 1899, p. 21. g Idem, 1884, pp. 79-81. * Idem, 1895, p. 161.
CHARACTER OF GROUND WATER. 171

Typhoid at Easton in 1895 was traced to a well adjoining a pig pen.a 

Thirty cases of typhoid in Glastonbury in 1895 were caused by a contaminated well at Hopewell. 6 An investigation of the typhoid at 

Ridgefield in 1901 showed that the entire ground water of an area 

covering several blocks had been contaminated by sewage.c The 

typhoid epidemic, 84 cases in all, at Bristol in 1903 was due to 

infected water from a farm well and spring.d Several less conspicuous occurrences of typhoid are likewise directly traceable to contaminated ground water.

"It is now universally recognized that the degree of prevalence of 

typhoid fever in a given community is a reliable measure of the 

extent to which sewage is an ingredient in its drinking water. The 

prevalence of typhoid in cities is a true index of the quality of the water 

supplies." 6

The annual death rate from typhoid in Connecticut has been 

steadily decreasing, and this satisfactory record is due largely to the 

increased attention paid to the character of water supplies.

CONTAMINATION BY SEWAGE.

Sewage is the most widespread source of contamination of water 

in springs and wells. Drainage from vaults, cesspools, broken, sewers, slops thrown on the ground, pig pens, and other sources of filth 

passes readily into the ground water and is the common vehicle for 

substances dangerous to health.

LOCATION OF WELLS.

The location of a well is the most important consideration in 

obtaining pure water. The well should be placed at a considerable 

distance from any known source of contamination, on ground of 

relatively high elevation, and should be surrounded by an open, clear 

space, preferably grass covered. The direction of the flow of ground 

water for the area should be determined, if possible. Many wells in 

Connecticut are located in utter disregard of the simplest principles 

governing the movement of underground water. Instances might be 

cited where cesspools and other waste reservoirs are within 25 feet of 

wells used for domestic supply. For some wells the worst possible 

locations seem to have been selected. The writer has noted between 

40 and 50 wells located on slopes below cesspools, in such manner 

that the contaminated waters, either in drift or in rock, are carried 

with certainty into the wells. It is not the depth but the location of 

a well which usually determines its purity, and a 20-foot well located 

with care may be much safer than a 100-foot' well sunk without

a Ann. Kept. Connecticut State Board of Health, 1895, p. 90. d Idem, 1903, p. 88. 

6 "Idem, m1895, isuop. 99. yy« Idem, 1899, p. 21.

cldem, 1901, pp. 301-305.
172 UNDEBGBOUND WATEE RESOURCES OF CONNECTICUT.

regard to surrounding conditions. A good illustration of this is the 

well on the New Haven Green, a shallow well in the heart of the 

largest city of Connecticut. The quality of the water is good, because 

the surface about it is protected on the south and east by pavements 

and because its water is received from the Green, a grass plot 16 

acres in extent, kept clean by the city authorities.

There is a general impression that soil will filter the impurities from 

water within a few feet of its source and that contamination of wells 

is due chiefly to material falling in at the top. No more dangerous 

error could be propagated. The purifying power of a soil is limited 

and it may easily be overburdened. In fact, the value of any soil 

filtration is uncertain, and it is impossible to state that water will be 

purified by passing through any amount of soil. The uncertainty is 

greatly increased by the existence of more or less open channels, 

which offer rapid passage to underground water with little filtration.

DEPTH AND CONSTRUCTION OF WELLS.

Shallow wells are much more likely to become contaminated than 

deep wells, and as probably 80 per cent of all wells within the State are 

less than 25 feet in depth, the importance of care in their maintenance 

is evident. There is in Connecticut, particularly in the rural districts, 

a strong prejudice in favor of the shallow, open well and a belief that 

clear, sparkling, palatable water is sure to be pure. The danger in 

these beliefs is very real, for certain parts of sewage tend to give 

water a sparkle which is highly appreciated by those unacquainted 

with its character. Drilled or bored wells have many advantages 

over shallow dug wells. There is less chance for foreign substances 

to drop into the well, and it is possible to shut off all surface and 

seepage water. The "old oaken bucket" has sentimental advantages, but iron pipes and creaking windmills are much better symbols of the purity of drinking water.

CONTAMINATION IN DIFFERENT ROCK TYPES.

Contamination of water in shallow drift wells has been the cause 

of many typhoid epidemics in Connecticut, as at Bristol, Easton, 

Glastonbury, Guilford, Madison, Middletown, Portland, Bidgefield, 

Stamford, and Stafford. The water supply at Camp Coffin was found 

to be contaminated in 1896 by water that collected in a pool used for 

washing clothes and reached the well by sinking through a considerable depth of sand and gravel. In 1903 the Chamber of Commerce 

of New Haven made an investigation of the local water supply, which 

led to the recommendation that all wells within the city should be 

abandoned as sources of water for domestic uses. The wells examined 

are mostly in till or stratified drift, range in depth from 20 to 220 feet,
CHARACTER OF GROUND WATER. 173

and are located in all sections of the city. Six samples were taken 

from wells 20 to 30 feet deep, eight from wells 30 to 50 feet deep, 

five from wells 50 to 100 feet deep, and nine from wells over 100 feet 

deep. The committee reported that, with the exception of a few 

samples from the outskirts of the city, all showed evidence of a past 

contamination in a more or less marked degree. In Hartford, 

Waterbury, and other cities analyses of water derived from sand and 

gravel deposits commonly indicate considerable sewage contamination, although the water is obtained at points 30 to 50 feet below the 

surface. In fact, it is doubtful if any well is safe in a thickly settled 

community.

Spring water may likewise become contaminated by sewage-laden 

ground water, as illustrated at Forestville and South Norwalk during 

the typhoid epidemics of 1900. a

Though drilled wells are much less subject to sewage and drainage 

contamination than shallow-dug wells of large diameter, equal care 

should be taken in their location. A number of deep wells have been 

drilled in the low central portion of Hartford, and many of them show 

heavy contamination in waters supposed to be derived more than 200 

feet below the surface. This is a portion of the city which received 

for years a large amount of drainage, so that whatever water enters 

the rock through the soil carries with it considerable contaminating 

material. Some of this water finds a ready passage through more or 

less open joints and enters the wells. The contamination of many 

such wells results from imperfect casing and the consequent entrance 

of water from the surface. There is little doubt that in certain wells 

imperfect joints allow shallow waters to enter the well at the contact 

of the rock and the drift. Such poor construction may be due to 

carelessness, or to intention, owing to the desire of the driller to 

obtain a sufficient supply of water. The entrance of any water at the 

junction of the casing and the rock may be detected if a mirror is 

used to reflect light into the well.

That contaminated water may circulate through considerable distances of sandstone is shown by the experience of Hartford, already 

described. At the Wallingford Sanitarium a well was contaminated 

by gasoline which flowed through the bedding planes of rock for a distance of 225 feet at a depth of 8 feet below the surface. Many similar cases might be cited.

Even wells sunk in granite and other crystalline rock are not free 

from contamination by circulating water. The typhoid epidemic at 

Sachem Head was caused by drinking water from a well blasted in 

rock to a depth of 16 feet. It was shown that the contaminated 

water passed through joints for a distance of 6 feet. At Millstone

oAnn. Kept. Connecticut State Board of Health, 1900, pp. 274-285, 286-289.
174 TJNDEBGBOTJISrD WATEE EESOUECES OF CONNECTICUT.

Point brackish water was seen to be supplied from a rock seam at a 

distance of 150 feet. Part of the ground water of Fishers Island is 

known to come through crystalline rock from the Connecticut mainland, 3 to 4 miles distant.

CONTAMINATION BY SEA WATER.

The Connecticut wells which have been contaminated by sea water 

are within 200 or 300 feet of open salt water, on old salt marshes, 

along tidal streams, or on islands. They are practically all in rock 

where the surface water has presumably been entirely cased off. 

The surface water, however, is usually fresher than that derived from 

the rock itself. In a well drilled for the Norwalk Iron Works Company, Norwalk, at an elevation 10 feet above sea level, fresh water 

was found in sand and gravel deposits at a depth of 60 feet, but salt 

water only was obtained at lower levels in the rock. The well was 

accordingly plugged at a depth of 60 feet and the rock water excluded. 

At many points along the coast pipes have been driven in deposits

FIGURE 30. Diagram illustrating the manner in which a well near the sea may be contaminated by salt 

water during the dry season. A, normal water table; B, depressed water table.

of sand and gravel near the shore and abundant supplies of fresh 

water have been obtained. These wells may, however, receive increments of salt water when the water table is brought below sea level, 

either by pumping or by dry seasons. In deep-driven wells near the 

shore which derive their supplies from the bottom of closed tubes, 

the head of fresh water is almost without exception sufficient to prevent the inflow of brine. In New Haven a series of wells have been 

driven through 6 feet of salt water into the sand deposits below and 

have obtained good supplies of fresh water.

In wells deriving water from rock in which the supply necessarily 

comes through fractures it is possible that the fractures may have 

such position as to give more ready access to sea water than to fresh 

underground waters. The possibility of contamination by this 

process increases rapidly with nearness to the sea, especially if the 

rock outcrops beyond the shore line. Figure 30 represents the 

direction of circulation of water contributing to such well, the ground 

water above the rock being entirely cased off.
CHARACTER OF GROUND WATER. 175 

RELATIVE VALUE OF WATER SUPPLIES.

Experience has shown that water in Connecticut is to be recommended for domestic use in the following order: (1) Surface supplies, preferably from lakes that are constantly under supervision and 

subjected to frequent inspections and .examinations; (2) deep wells 

so located that the surface area contributing to them is known to be 

free from contamination; (3) springs, especially deep-seated ones, 

like those along fault lines known to derive their water from regions 

not subject to contamination; (4) shallow wells and intermittent 

springs; (5) lakes and streams whose character has not been carefully 

determined.

ANALYSES.

In the following tables of analytical results the data are given in 

ionic form, in parts per million, having been recomputed, if not 

originally expressed in that manner. The column headings are in 

general self-explanatory. "Total solids" indicates the total dissolved matter found by evaporating a measured quantity of water 

and weighing the dried residue. "Organic and volatile matter" represents the difference in weight between the dried solids and the solids 

after being ignited at low red heat; the figure serves as a rough measure of the organic matter, though it also represents loss of water of 

crystallization, volatilization of some inorganic constituents, and 

other factors. The term "total hardness" is given to a figure 

found by adding standard soap solution to a measured amount of 

water till the mixture forms a good lather when shaken vigorously; 

the equivalent of the quantity of soap consumed is usually expressed as calcium carbonate (CaCO3 ). The " permanent hardness" 

is found by adding soap solution to water that has been boiled and 

filtered; it represents the hardness due to calcium and magnesium 

in equilibrium with acids other than carbonic acid. The " temporary 

hardness" is estimated either by subtracting the permanent from the 

total hardness or by titrating the water with normal acid.
176 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

crystalline rocks. Analyses fromwell of waters 

million.] [Parts per

"o

 3

1

l|

3|

CD

O

CD a, 

|1|

CO '"^

ca ca.oO

CD CD

Sodium 

and alcium Magnesium 

(Ca). (Mg)potassium 

(Na+K).

Hardness asCaCO3. 

Silica Iron C

'a? 

to

O 

%

(3 X

^. s 

3£

"a 

"o

t^

Analyst.

<s

d

ss.s

oco

t^ G3 

lOr-l

I CO OJ 

EN CO

i^ 01 ^

o0

r 

> 

00

^

Cf

CD 

C3

g

H. Southern Eng. Co.... 

Unknown. .............

a ss i~l -O

0

r

pi i i CO CO CO . .05 IO t~ . . 

. . i 1 00 i-l ' -

CD <N CD GO <N "^ O^Ot^-Oi CD O i-H T I <N OOt-i ICO i I i-H

coioesiocsicsiesiOTt*ccccco<Ni>-cct^occccciio

 o w^w^-oj « fl^'^ 10.

_tp^ »O O5 O5 * _tO tOCO _tOCO CO i-l * CX) tO MCN CN

M KK ffi KK

^

CO iO

00 ' 

CN .

CO CO 

COCN

.......| E Smith...... Unknown. .............. Wheeler. S.P..........

 g 

f

«

0.

o:

H 

C

OOOCO Ot- 00 CT i 1 1 1 CN ^ »O »O "~

i-l £ 0- CN CO

caM

3 -a

3

s

t- O5CN

MtO 

53 : :

o ..tote.. .... ....

00 ..,,.. .,,.,....

: : : : : :

g§3£c^8£§§§g

V V.

i§§SSS8§

numbers refer wellrecords 78-89. Thetheo a onpp. 

6 Trace oflithium, 

drilled feet;in rock. I.Glenbrook, Stamford; Well ofC.Hempstead, 140 80c 

deep. Well ofStamord Co., Stamford; feet d Water 247

months laterthan firstanalysis. Seven < 

/Same well depth of feet.a122 

year's constant wellSame afteruse. 9 one 
Analyses of well waters from sandstone

[Parts per million.]

To.o

8

<«> 

15 

26 

d)

«)

369 

74 

(A) 

85 

(0 

112 

V) 

117 

152 

165 

189

Analyst.

H.E. Smith............

G. H. Seyms............

.....do..................

.....do..................

.....do..................

.....do..................

H.E. Smith............

H. E. Smith............

G. H. Seyms............

H.E. Smith. ...........

.....do..................

.....do..................

Hardness as 

CaCO3 .

Total.

48

240

274

52

28

110

Alkalinity.

96

Silica 

(St02 ).

20

18

19

14

Iron

(Fe).

15

.7

2.0

Trace.

Calcium

(Ca).

»326

High.

146

330 

High. 

82 

High. 

10

44

Magnesium

(Mg).

6106

High.

31

9.9

41 

High.

11

Sodium 

and 

potassium

(Na+K).

118

90

24

5.5

Carbonate 

radicle 

(CO,).

( 6)

(

a The numbers refer to the well records on pp. 116-123.

6 Carbonates of calcium and magnesium, 54 parts; trace of lithium (Li) and the p

c Well of Mount Carmel Bolt Co., Mount Carmel, Hamden; dug 35 feet deep and 

d Well of Billings & Spencer Co., Hartford; drilled 250 feet

« Well of G. W. Brown, Linden Building, Hartford; drilled 235 feet.

/ Well of Hartford Woven Wire Mattress Co., Hartford; 250 feet deep; water at 2

g Drilled well of Long Bros., Hartford.

A Well of Goetz Bakery, Manchester; drilled 200 feet deep in soft brownstone.

i Well of Charles Parker, Meriden; 1,000 feet deep.

i Well of Tuttle Brick Co., Newfleld, Middletown; drilled 264 feet.
Analyses of well waters from stratified drif

[Parts per million.]

No.a

45 

50 

(0) 

56 

( c)

' Analyst.

T. B. Osborn. ..........

H. E. Smith............

Hardness as 

CaCO3 .

Total.

134

Alkalinity.

..... ....

Silica 

(SiOs).

12

Iron

(Fe).

Trace.

Calcium

(Ca).

74 

31 

High.

36

Magnesium 

(Mg).

11 

30

Trace.

Sodium 

and 

potassium

(Na+K).

85

9

Carbonate 

radicle 

(CO,).

B

bo

ra

(H

a, The numbers refer to the well records on pp. 152-155.

6 Well of National Folding Box and Paper Co., New Haven; 2-inch test 

c Well of Waterbury Brass Co., Waterbury; 35 feet deep.

Analyses of well ivatersfrom till. 

[Parts per million.] 

Well.

(a)

W

Analyst.

H. E. Smith............

Hardness as 

CaC03 .

Total.

21 

54

Alkalinity.

Silica 

(SiOs).

Iron

(Fe).

Calcium

(Ca).

Magnesium 

(Mg).

Sodium 

and 

potassium

(Na+K).

Carbonate 

radicle 

(CO,).

B

bo

ra

(H

a Well of R. K. Jones, Turnerville, Hebron; dug 16 feet 

6 Well of W. E. Bond, New Canaan; dug.
Analyses of spring waters. 

[Parts per million.]

fo.a

1 

4 

8 

9 

19 

23 

(6 ) 

32 

34 

«)

; !

9) 

55 

(») 

62 

63 

65

(*)

69 

66 m

83 

90

Analyst.

R. H. Chittenden.......

H. E. Smith............

C. A. Seitz. .............

H. E. Smith............

S. P. Wheeler...........

H. E. Smith............

H.E. Smith.. ..........

.....do..................

.....do..................

.....do..................

.....do..................

.....do..................

.....do..................

H.E. Smith............

R.H. Chittenden.......

H.E. Smith............

Hardness as 

CaCOg.

Total.

43

22

73

16 

23

58 

36

23

44

20 

42 

7.0

28

Alkalinity.

18

59

13

47 

30 

8.0

40

38

Silica 

(SiOa ).

is

14 

25

6.0

9.5

7.2

23

10 

6.3 

34 

11

Oxides of iron 

and aluminum 

(FeaOs+AlaOs).

0.3 

.2 

14

1.2

1.0 

Trace.

11

.2 

.4 

13

.8

Calcium. 

(Ca).

4.0 

2.4 

12

2.1

10 

4.4

6.0

3.0 

2.2 

5.1 

8.3

Magnesium 

(Mg).

1.1 

1.1 

9.0

1.4

6.0 

.4

2.2

1.0 

1.0 

.3 

2.6

Sodium 

and 

potassiu

(Na+K

4

3

116

14

6

5

3

7

12

8

a The numbers refer to the spring records on pp. 191-194.

b On Whitman place, at Fannington.

c Spring of J. V. Palmer, Millville, Naugatuck.

d Cherry Hill Spring of H. B. Gorham, Highwood, New Haven

e Spring of Mrs. D. Auger, Fair Haven, New Haven.

/ Spring of Stilhnan Water Co., near East Rock, New Haven.

g Spring of G. H. Bush, Norfolk.

A Quinnipiac Spring of L. R. Hemingway, North Haven.

* Spring of Z. Chaflee, Pomfret.

i Phosphates present.
CHAPTER IX. 

WELL CONSTRUCTION IN CONNECTICUT.

DUG WELLS.

The common type of well in Connecticut is naturally the most 

primitive type an excavation in the ground to a depth below the 

level of ground water, the interior being lined with brick or stones. 

These wells are usually dug in clay, sand, and glacial drift, but a few, 

where the surface material is shallow, are blasted into the underlying 

rock, Some wells are dug into. rock and water is obtained from 

crevices, but in general the rock excavation serves merely as a reservoir for water draining from the drift. Such wells are usually 2 to 4 

feet in diameter inside the stone casing and from 10 to 50 feet in depth.

Very few dug wells are properly constructed in Connecticut and 

many are extremely old, it being not unusual to find wells sunk more 

than a hundred years ago. The ordinary stone casing is very inefficient as a protection against the entrance of surface water, the 

openings between the stones being in many wells large enough to 

permit the passage of rats and other small animals. Brickwork is 

used as a lining in some of these wells, but probably the safest method 

of protecting such a well against contamination is by tiling.

Too much care can not be taken in the location and protection of 

open, shallow wells. A well. of the open type containing clear, 

sparkling water has been considered one of the most valuable possessions of home. Such wells are, however, peculiarly liable to dangerous contamination. Many of them are located on low ground, 

because water may be procured there at less expense, and some are 

walled up with poorly cemented stone and either open or covered 

only with loose boards. The tops of many of these wells are but a 

few inches above the level of the ground and may readily serve as 

resting places for impurities carried by wind or on the feet of animals 

and men. a The advantages of the small drilled or bored well, as 

compared with a dug well, are the decreased probability of the 

entrance of impurities at the time the well is put down, less opportunity for rats, frogs, and other animals to enter the well, and the 

ease of shutting out surface and seepage waters. It can not be too 

plainly stated that open wells are dangerous to health.

a See a discussion of this subject by Crider, A. F., and Johnson, L. C., Water-Supply Paper U. S. Geol. 

Survey No. 159, 1906, pp. 74-75.

180
WELL CONSTKUCTION. 181

As dug wells usually reach but a few feet below the level of ground 

water, any fluctuations of the water table materially affect the 

yield of the wells. In dry seasons the water table may sink below 

the bottom of the well, with a consequent total loss of supply. This 

loss of supply, owing to drought, is more noticeable in wells located on 

hills than in those along stream channels.

Dug wells are of value in rural communities, but in cities and 

thickly populated areas they are extremely unsafe because of the 

general contamination of the soil and the impracticability of keeping 

out surface water.

The average cost of a well of this type, as ordinarily constructed 

in Connecticut, is about one-fourth to one-half that of the average 

drilled well, but when it is carefully constructed and cased so as to 

admit water only at the bottom, the cost is not far from that of a 

well constructed on more sanitary principles.

DRIVEN WELLS.

For wells in sand and gravel a method of well construction is 

recommended which, although commonly used throughout the United 

States, is little appreciated in Connecticut. This is the driven well, 

consisting essentially of a pipe, usually 1 to 2 inches in diameter, 

driven into the ground by means of a heavy weight. These pipes 

are perforated near the base either by boring round holes or by cutting straight slits with beveled inside edges. In some wells the perforated pipe is fitted with a jointed conical tip; in others a hollow 

open tube is fitted with a perforated section of some noncorrosive material and a sharp steel shoe, so that it can be driven directly into 

the ground. The contents of the tube are then washed out by water. 

As the water can enter the well only through the perforations, the 

position of the base of the pipe determines definitely the depth at 

which the water enters a well of this type, thus differing radically 

from a dug well, in which more or less water enters from top to bottom. Such wells are usually put down in a connected series known 

as "gangs," all connected with a central pipe or main through which 

the water is pumped. In very favorable localities large supplies may 

be obtained in this way at relatively small expense. There are several such gangs in New Haven; one of 34 wells at the Yale gymnasium 

which supplies the swimming pool with 150 gallons a minute was 

driven at a cost of $600. Another gang of wells furnishes the Yale 

dining hall with water for cooling, and 40 such wells, each with a 

diameter of 2 inches, are used by the Hygienic Ice Company.

Wells of this type can be driven only into unconsolidated material, 

where the water horizon is in sand or gravel. Many places in Connecticut are favorably situated for obtaining water from driven wells,
182 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

particularly those towns along the main river valleys and near the 

coast where the sand deposits are heavy. The average cost of such 

wells is 70 cents a foot and the yield and character of the water obtainable at any place may be readily and cheaply ascertained by 

means of a single test well costing not more than $20 or $25.

The quality of the water obtained from driven wells is largely 

determined by their location in reference to possibility of sewage 

contamination. Although derived from greater depths the water 

from driven wells of moderate depth is not necessarily better than 

that from dug wells situated in the same contaminated district, for 

the flow of ground water through sand and gravel is more rapid than 

through till, in which the dug wells are commonly constructed. In 

thickly settled communities the water of driven wells often shows 

contamination. There are many localities where unpolluted waters 

may be obtained by driven wells and this method of construction is 

advised for the Connecticut Valley lowlands, where larger yields 

and softer quality may generally be obtained from drift than from 

the underlying sandstone.

DRILLED WELLS.

Of the various methods of obtaining supplies of underground 

water, drilled wells should probably rank first in importance. Although the most expensive, they are most free from contamination 

and yield the most constant supplies.

As the process of drilling wells is not generally familiar, it seems 

advisable to present a brief statement of the methods employed in 

Connecticut. The two main methods of well drilling are known as 

churn drilling and rotary or core drilling, the former being far the 

more common. A churn-drilling rig includes a movable boiler and 

engine mounted on a frame which is ordinarily drawn by horses or by 

traction. Attached to the front of this rig is a collapsible derrick 

which acts as a support for the rope and tools used in the drilling 

operation. The drilling tools consist of a heavy steel bit, with other 

devices, such as jars and sinkers, which serve to prevent wedging 

of the bit, to add weight to the blow, etc. The bit is supported by 

the rope, and by means of a walking beam or other device is lifted 

and allowed to drop suddenly 20 to 30 inches, giving a succession of 

blows at the rate of 25 to 40 a minute. The sharp edge of the heavy 

bit breaks and crumbles the rock where it strikes, and by continually 

twisting the supporting rope the bit is made to strike a new spot 

each time. The result is a round and even hole with a diameter 

slightly greater than the width of the bit. The diameter of the drill 

hole is usually 6 inches, although 8-inch wells are not uncommon.

Owing to the presence of glacial drift, a layer of sand or gravel or 

till is usually traversed before the drill strikes rock. The unconsoli-
WELL CONSTRUCTION. 183

dated material carries more or less "surface water/' which it is desirable to exclude. To accomplish this purpose, the careful driller 

inserts a casing, consisting of heavy iron pipe with water-tight joints. 

The iron casing should extend from the surface to bed rock, and it is 

particularly important that a tight joint be made where the casing 

meets the rock. This junction should always be examined by means 

of reflected light from a mirror to detect the presence of any surface 

water. Water is kept in the hole during drilling operations, and after 

every few feet of progress the tools are removed and the well cleaned 

out by means of a "sand bucket," a hollow tube with a valve at the 

bottom.

As the chief water horizon in drift is at the contact of rock and the 

overlying material, it is important to know the character of the rock 

mass encountered. This is not always easy to determine, for it is 

not an uncommon occurrence to strike large bowlders that lie many 

feet above the bed rock and may be readily mistaken for solid ledge. 

The driller may assure himself in this regard by drilling into the supposed ledge. If it is a bowlder he will pass entirely through it in the 

course of a few feet. Moreover, the nature of the rock wilj ordinarily 

indicate whether it is part of the underlying strata or a fragment 

carried from a distance.

The rate of drilling, or number of feet a day, varies widely with 

the character of the rock, and the price charged for drilling is ordinarily regulated by the driller's knowledge of the bed rock in the 

locality. In crystalline rocks to which the drillers generally apply 

the term "granite" the rate varies between 2 and 25 feet a day. 

The price for drilling in crystalline rocks varies between $2.50 and $8 

a foot, the average being $4.25 a foot. In such wells the same rate 

is charged for the surface material as for the rock, but the driller 

furnishes the casing without additional expense. In sandstone 

drilling is much easier and the average price charged is about $2 a 

foot for a 6-inch well. For an 8-inch well the price is 50 to 75 cents 

a foot additional. The average drilled well costs more than a dug 

well and much more than a driven well, but it possesses advantages 

not shared by the other types.

Core drilling or "diamond drilling" has been employed with considerable success by one contractor in the western part of Connecticut. 

In this process the drilling tool consists of a rapidly rotating pipe, 

the end of which is edged with diamond fragments, chilled steel, or 

other sharp cutting material which wears away the rock below the 

cutting edges and leaves a cylindrical core within the pipe. This 

core is broken off and removed by various devices, leaving a hole of 

the desired diameter.

Drilled wells are far safer in sanitary respects than either of the 

other types considered. The process of construction is such that
184 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

with proper care the surface water may be entirely cased off and a 

supply obtained from a sufficient depth to insure safety. It should 

not be forgotten, however, that fissured rock may have openings 

large enough to allow the passage of water without adequate filtration; this is much more likely to occur where the rock outcrops in 

the vicinity of the well than where a mantle of glacial drift overlies 

the ledge. In one place near New Haven where the soil was only 2 

feet deep, gasoline leaking from a buried tank at a distance of 150 

feet entered the rock and was carried into a drilled well at a depth 

of at least 18 feet. The gasoline may have entered the well through 

a .crevice or by percolation through the rock itself. Although the 

contamination of deep-drilled wells is possible, it is an unusual occurrence and is generally due to imperfect casing.

A dishonest driller may sink a deep hole into dry rock and arrange 

the casing in such a manner that the water from the soil and the 

upper surface of the rock enters and fills the hole, giving the appearance of a yield from a great depth. The water is large in amount 

and may show a satisfactory analysis. Sooner or later, however, the 

ground water establishes channels of ready circulation and any contamination from surface water may enter and penetrate to the bottom 

of the well.

To give a minimum possibility of contamination the following 

points should be observed: The well, of whatever kind it may be, 

should be located as far away from and as high above sources of contamination, like cesspools, open sewers, and barnyards, as circumstances permit; the well site should be selected where the glacial 

drift above the rock is deep, rather than on a thinly covered rock or 

on bare ledges; the well should be properly cased a point to which too 

little attention is paid in constructing either dug or drilled wells. 

The driller usually furnishes casing from the surface to the rock, but 

where circumstances indicate that more casing is needed for safety 

the owner should not hestitate to assume the slight extra expense 

required to insure absolutely safe construction.
CHAPTER X.

SPRING WATERS.

INTRODUCTION.

If the surface of Connecticut were level and the soil of uniform 

composition and texture, the ground water would tend to assume a 

plane surface at a small distance below the cover of soil. Such a 

water table would rise and fall with each increase and decrease in 

precipitation, but there would be no well-marked channels to conduct ground water to the surface. Connecticut, however, is a region 

of topographic inequality and variability of soils and bed rock and 

the imprisoned waters find many avenues of escape.

The normal outlet for ground water is near the level of lakes, 

swamps, and rivers, where it emerges in large amounts although 

rarely in definite channels. Below the earth's surface there are 

innumerable openings from which water is poured unnoticed into 

streams, lakes, or marshes along the shore line where salt water 

mingles imperceptibly with fresh. If the floor of Connecticut River 

were exposed suddenly to view by removing the water, we should see 

tiny rills issuing from cracks and seams and porous places in the rock 

and drift forming the river bed.

To speak broadly, any definite outlet for ground water is a spring, 

regardless of its size or of the geologic conditions which surround it.

TYPES OF SPRINGS.

There are springs which emerge from the ground with a force to 

turn mill wheels and with a volume to float a river steamer. There 

are springs which come from great depths and furnish vast quantities 

of hot water. The springs of Connecticut are of another kind 

small and widely distributed, containing cold water of exceptional 

purity, and those suitable for domestic purposes and local supplies 

are to be numbered by the thousand.

The three types of springs commonly found in the State may be 

classed as seepage springs, stratum springs, and fault or joint springs.

SEEPAGE.

Many hillsides and lowlands bordering streams and ponds are 

saturated with moisture and the ground is soft and springy under the 

foot. This is especially noticeable during the early part of the year, 

when ground water is particularly abundant. These marshy places

185
186 UNDERGROUND WATER RESOURCES OF CONNECTICUT.

are "seeps" and are caused by ground water returning to the surface from the rocks beneath. Such diffused seepage, rather than 

drainage along definite channels, is the normal method for the escape 

of water from the ground, and, in fact, it is only where this return seepage is concentrated by some local geologic conditions that a stream 

issues from the ground as a spring.

When seepage is restricted to a limited area it may form a seepage 

spring, in which the water slowly escapes from sands or gravels over 

a space of a hundred square feet, more or less. In its natural state 

a seepage spring is marked by the presence of water-loving plants 

and in many places also by the presence of an oily-looking scum or 

film on the water, which is often mistaken for petroleum but which 

in reality is the result of decomposing vegetation. The particular 

factors which have served to concentrate the water at this place are 

not always easy to determine, but ordinarily a slight difference in 

texture of the sands or the presence of a thin mantle of drift over 

rock is sufficient to bring the water to the surface. As a rule the 

water can be still further concentrated by digging a hole or sinking a 

barrel into the ground in the zone of most vigorous seepage, thus 

furnishing a small local reservoir which receives the ground drainage 

from a larger area.

There is, of course, no sharp line between general diffused seepage, 

seepage springs, and springs proper, although the term " spring" 

ordinarily implies a distinct stream of water issuing with some force 

from an opening a few inches or, at most, a few feet in diameter. 

No distinct channel need be exposed at the surface, but there must 

be at hand a definite horizon or zone along which the circulation of 

ground water is sufficiently rapid to form a constant stream of appreciable size.

STRATUM SPRINGS.

The horizon most suitable for the transmission of large amounts 

of water is the plane between strata of different degrees of permeability. In such positions the water occupies a definite zone in some 

porous stratum and is confined by strata through which it passes with 

difficulty. A stratum spring may originate between two sedimentary 

beds, between drift and underlying rock, between clay and sand, or 

even between sands of slightly different structure. Where the edges 

of water-bearing strata are exposed at the surface, as in stream valleys or in artificial sections, the water is allowed to escape and soon 

tends to excavate channels along which further progress is rapid.

Where an impervious bed overlain by porous strata is exposed for 

long distances, a line of springs may be formed at the contact between 

the strata. Lookout and Raccoon mountains, in Tennessee, are bordered by a fringe of springs which reach the surface at the contact 

of the capping sandstone with a prominent bed of shale. In the
SPUING WATERS. 187

Snake River canyon, Idaho, a line of springs of great volume emerges 

from sedimentary beds underlying lava. The edge of the North 

Haven plain in Connecticut is marked by numerous springs. This 

sand plain is underlain by clay which forms a basement bed for the 

ground water, and where the beds are truncated by Quinnipiac 

Eiver springs emerge from the bedding plane between the clay and 

the overlying sands. Similar conditions are reported from the Po Valley of Italy, where the water penetrates the sand and remains underground for several miles, finally emerging as a long line of springs 

where the water table is forced to the surface by more pervious beds. 

Probably 75 per cent of the springs in this State owfe their existence 

to the concentration of water between beds of sand, clay, till, and 

rock.

FAULT AND JOINT SPRINGS.

Ground water occupies all open spaces within the earth's surface 

and moves along joints and faults and seams as well as between beds 

of stratified series. The rock walls forming the two sides of a fault 

are usually sufficiently separated to allow the passage of water and 

the fissure is usually of sufficient depth to permit a profound circulation. Ground water from a large area may be contributar}^ to a 

single fault zone and may exert pressure sufficient to drive the water 

along the crack with considerable power. Most of the famous hot 

springs of the world are located on fault lines. Many small springs 

in Connecticut are located along faults; 0 their temperature, however, 

indicates that the water in them does not come from very great 

depth.

TEMPERATURE.

The temperature of the ground below a depth of 50 or 60 feet is not 

affected by daily or seasonal changes at the surface, and the temperature of water which comes from those depths is therefore subject to 

only slight variation, remaining at about 47°, which is the average 

annual temperature of the State. No hot springs are reported from 

Connecticut, and temperatures under 45° are rare. Of the springs 

recorded on pages 191-194 only five have temperatures less than 45°, 

and none over 55°. The well-known Arethusa Spring at Seymour 

has a temperature of 47°, which coincides with the average annual 

temperature of the State. In a nonvolcanic region like Connecticut 

the temperature affords some indication of the depth from which 

water comes, and the absence of high temperature implies that even 

in fault springs the occurrence of water is relatively a surface phenomenon.

It is frequently reported that the water from springs is colder than 

normal in summer and warmer in winter. These statements, however, are not borne out by the facts.

o See map by W. H. Hobbs, in Water-Supply Paper U. S. Geol. Survey No. 67,1902, p. 80.
188 UNDERGROUND WATER RESOURCES 07? CONNECTICUT. 

INTERMITTENT SPRINGS.

If Connecticut received a uniform and evenly distributed rainfall 

and were forest covered, the springs of the State would be practically 

permanent in position and constant in yield. The rainfall, however, 

is not uniformly distributed, the region is partly woodland and partly 

farms, and the strata consist of many varieties of rocks and soil. 

The result is that some springs are constant, some vary in yield, and 

some cease entirely during parts of the year. The flow of a spring is 

much more constant than the rainfall, because .water in. rocks is 

absorbed and stored much more rapidly than it escapes, and the 

rainfall from a large area returns to the surface through a few channels. The soil is a reservoir filled within a few hours and then allowed 

to drain off for several weeks. In Connecticut the supply of water in 

the soil is usually renewed by rain before the reservoir is emptied, and 

the springs are kept flowing at varying rates of speed.

FIGUKE 31. Diagram illustrating conditions for intermittent spring. For explanation, see text.

The fact that ground water returns to the surface gradually is the 

chief factor which insures permanency of flow and carries springs and 

rivers through periods of drought. In certain parts of the country 

the principal supply for rivers is furnished by ground water, and 

during parts of the year the only water which enters Connecticut 

brooks is supplied by springs and seeps.

A spring which normally gives a continuous flow may become intermittent during dry seasons. The hill shown in figure 31 consists 

of sand and till, which allows water to be absorbed in large amounts 

and to sink to the impervious stratum along which ground water 

flows to the surface as a spring at B. When the water stands at "S," 

temporary springs may form, which cease to flow when the water's 

level drops to "t." In unusually dry seasons the water table may 

sink below the second outlet, thus producing an intermittent spring 

from one that has been constant for several years.
SPRING WATERS. 189

/ 

MINERAL SPRINGS.

All springs contain mineral matter in larger or smaller amounts, 

but its presence may not affect the color or odor or taste of the water. 

In a popular sense, mineral springs are those which are notable for 

the large amount of their mineral content, for some conspicuous 

characteristic of the water, such as color, odor, or taste, or for the 

presence of unusual mineral ingredients considered to be of therapeutic value. Dissolved rock material is sometimes deposited about 

the mouths of springs in quantities amounting to several tons a year. 

Even the ordinary cold-water spring carries to the surface appreciable amounts of rock. It has been estimated that the combined 

activity of 900 ordinary springs in the eastern part of the United 

States results in piling up each year rock enough to form a block 10 

feet square and 2 miles long.

Several springs in Connecticut are reported to have medicinal 

value. Many springs, however, pass as medicinal merely because 

they have a forbidding odor or taste, and prove on examination to 

have little in their favor. It hardly needs to be stated that disagreeable characteristics are no evidence of the therapeutic value 

of water. There are no springs in Connecticut with an unusual 

abundance of rare mineral constituents, and few that are conspicuous 

because of their color and odor.

VOLUME OF SPRINGS.

Springs vary in size from minute trickling rills to streams that give 

rise to small brooks. The amount of water in a spring depends 

directly on the available supply from which it is drawn, and this in 

turn is directly related to the amount of rainfall and to the size of the 

area which is contributary to the spring. The attitude and structure of the rock are also important considerations. The rock may 

be stratified, may have open bedding planes of wide extent, or may 

be dense and massive. Its texture may be coarse or fine. It may 

be easily soluble or resistant to chemicals. Furthermore, the distribution of farm and forest land and the relative position of hills, 

plains, and valleys have much to do with collecting water and guiding it along the channels leading to a spring.

USES AND PRODUCTION OF SPRING WATERS.

The chief use of spring water in Connecticut is for domestic purposes. Thousands of houses are supplied by springs, either in their 

natural state or covered and connected with pipes, and some small 

villages derive a large proportion of their common supply from such 

sources. Springs are so abundant and so widely distributed that 

most farm houses have spring water either directly at hand or easily 

obtainable by a short pipe line.
190 TJNDEEGBOTJND WATEE EESOUECES OF CONNECTICUT.

The dairying industry requires large amounts of cold water flowing 

regularly through the cooling rooms, and Connecticut is highly favored 

in this regard.

Fifteen springs report sales of table water for 1908 and there are 

known to be many others which have more or less local use. About 

nine-tenths of the production is sold for table purposes. One spring 

is the site of a resort with accommodations for about 80 people. During 1908 the output of water increased about one-third and the value 

decreased one-seventh as compared with the record for 1907. The 

sale of water from 15 springs for 1908 was 424,826 gallons, at an 

average price of 9 cents a gallon.

The springs from which water was sold during 1908 are enumerated 

in the following list:

Althea Springs, near Waterbury, New Haven County.

Arethusa Spring, Seymour, New Haven County.

Aspinock Mineral Springs, Putnam Heights, Windham County.

Buttress Dike Spring, Woodbridge, New Haven County.

Cherry Hill Spring, Hamden, New Haven County.

Crystal Spring, near Little River, Middlesex County.

Elco Spring, Bristol, Hartford County.

Glenbrook Spring, Glenbrook, Fairfield County.

Granite Rock Spring, Higganum, Middlesex County.

Highland Spring, near Mount Higbee, Middlesex County.

Hillside Spring, Meriden, New Haven County.

Live Oak Spring, Meriden, New Haven County.

Mohican Spring, Fairfield, Fairfield County.

Oxford Mineral Spring, Oxford, New Haven County.

Park Spring, Norwich, New London County.

Pequabuck Mountain Spring, Bristol, Hartford County.

Quinnipiac Springs, Montowese, New Haven County.

Red Rock Spring, Meriden, New Haven County.

Rock Ledge Spring, New Haven, New Haven County.

Stafford Mineral Spring, Stafford Springs, Tolland County.

Varuna Spring, Stamford, Fairfield County.

RECORDS OF SPRINGS.

The following table and notes include the available statistics in 

regard to Connecticut springs:
Records of springs in Connecticut..a

No.

1

f,

3

4

, >

6

7

*S

9

10

11

12

13

14 

IS

16

17

IS

Town.

Avon..........

Bethel.........

Bristol.....'...

Canterbury....

.....do.........

.....do.........

Chatham......

.....do.........

Chester........

.....do.........

.....do.........

Columbia...... 

Cornwall......

Danbury......

.....do.........

.....do.........

Locality.

Collinsville....

Parkerville....

South Canterbury.

Middle Haddam. 

Cobalt.........

Cornwall

Bridge.

Owner or authority.

T. W. Sanford.....

Mrs. F. Konold....

Mrs. E.G. Fitzpatrick. 

Susie E. Witter....

Henry Baldwin. . . .

estate. 

H.S.Hurd. .......

C. B. McLean.....

B. Hanvood.......

Church.

S. B. West. ....... 

C. W. Everett.....

J.E.Walsh. ......

Water Co.

Location.

Hillside.......

Hillside.......

Base of hill....

Hillside.......

hill. 

Hillside.......

.....do.........

Base of hill....

Hillside.......

Base of hill....

Yield 

per 

minute.

Gallons.

OE

(")

2

7E

<«)

2

(d)

 -(V) -

(/)

Temperature.

"F.

Af)

4.Q1

Eft

42

55

Variation in 

flow.

weather.

weather.

weather and 

ceased once.

Qua

Soft

...do

...do

...do

Soft

lybe

soft.

Soft

...do

...do

Soft

o Additional details concerning springs marked with an * are given on p. 195. 

6 4-inch pipe.

c 1-i

<* 1-i
Records of springs in Connecticut Continu

No.

19

20

91

22

93

24

25

26

97

OR

on

30

01

^9

QQ

34

qe

36

37

38

on

40

Town.

Fairfield.......

.....do.........

.....do.........

.....do.........

Kent..........

Milford........

Montville..... 

.....do........

.....do........

.....do........

Locality.

.....do.........

Uncasville..... 

.....do........

Owner or authority.

Marion B. Williams.

H. G. Wright.....

C.W.Martin......

W. E. Wilcox.....

Chas. S. Johnson. .

Co. 

W. C. Clarke......

Location.

Hillside.......

Valley.........

Hillside.......

Base of hill....

Hillside.......

Valley.........

Hillside.......

.....do.........

.....do.........

Hilltop........

Valley.........

Slope..........

Valley........

Base of bluff...

Hillside.......

Base of hill....

Valley........

Hillside.......

.....do........

Yield 

per 

minute.

Gallons. 

3

10

10

15

(a)

(»)

14

8

..........

17

8

750

3

( c)

Temperature.

"F. 

46-52

46

55

53

48

51

50

45

50

48

Variation in 

flow.

dry summer.

.....do.........

season. 

Never failing..

weather.

stant.

.....do........

Qua

So

char

Soft

soft

Soft

...do

Soft, 

Hard

Soft

Soft

Soft

Hard

Soft

...do

...do

Har

Slig

hard

Soft, 

iron 

sulp
41

43

43

44

46

47

48

49

50

51

53

53

54

55

5fi

58

59

60

61

63

63

64

66

67

*69

70

71

73

....do........

....do........

NewMilford...

.....do........

.....do........

.....do........

.....do........

....do ........

.....do........

.....do........

lin.

ton.

.....do........

.....do........

Oxford ........

.....do........

.....do........

.....do........

Simsbury .....

.....do........

.....do........

City...............

Finishing Co.

W. H.Camp......

B.F.Judd. .......

Thos. B. Hewitt...

Mrs. M.C. Kite....

Carpenter & Williams.

Chas. T.'Ely......

provement Co.

S. P. Sanford. .....

Willis Covell

Chas. Holly.......

T. F. Gilyard......

R. T. French......

C.I. Leach........

N. W.Dodee......

Near top of hill

Valley ........

Hillside.......

.....do........

.....do........

.....do........

Hillside.......

.....do........

.....do........

ground.

Valley.........

.....do........

.....do........

Hillside.......

Flat...........

Hillside.......

.....do........

Hill...........

Hillside.......

.....do........

Base of hill.... 

Hillside.......

.....do........

Valley.........

4

(d)

30

15

(«)

(0

5

7

91

3

1

(n)

5

1

5 

1

1

45-56

42

50

52

48

40

47

44

.....do........

Slight.........

.....do........

.....do........

tion.

weather.

.....do........

.....do........

.....do........

..I.. do.. ......

.....do........

.....do........

.....do........

.....do........

Har

Sof

Sof

Har

har

Har

Sof

...do

...do

...do

...do

Soft, 

Sof

phu

Sof

...do

...do

...do

...d

...d

...d

...d

»IJ-inch pipe.

t> 1,000 gallons per day.

e J-inch pipe. 

1-inch pipe.

e 4-inc

/ J-inc
Records of springs in Connecticut Continue

No.

73

74

75

76

77

78

79

80

01

P?

83

84

85

86

87

88

89

*9ft

Town.

Springs.

Suffield........

.....do.........

Wilton........

.....do.........

.....do.........

Locality.

South Willington.

Winsted.......

North Windham.

Ower or authority.

N. W. Mitchell.

Mineral Water Co. 

B. F. Williams....

D. S. Guthrie......

W. T. Church.....

R. E. Holmes.....

E.H. Hall. .......

W. H. Harvey.....

Windsor Water Co.

Water Co.

Location.

Base of hill....

.....do........

Hillside.......

.....do.........

.....do.........

.....do.........

.....do.........

Hillside.......

Base of hill....

Hillside.......

Base of hill....

Hillside.......

Valley.........

.....do.........

Yield 

per 

minute.

Gallons. 

(a)

ii

i

(a)

(a)

<*)

Good.

(0

10

2

3

Temperature.

°F.

52

45

50

50

50

50

Variation In 

flow.

weather.

.....do.........

weather.

.....do.........

Nearly constant.

"weather. 

Constant ......

heavy rain.

per cent in 

dry weather.

Qu

Sof

Sof

...do

...do

...do

...do

Sof

...do

...do

Sof

..-.d

...do

...do

...do

...do

o 2-inch pipe. 6 IJ-inch pipe. 
SPRING WATERS. 195

NOTES.

8. Located at the northern edge of Whortleberry Hill, a ridge of gneiss overlain by 

sandy till. It is situated in a large seepage area from which flows probably twice as 

much as issues from the spring. Although rock outcrops are near at hand, it is probable 

that the water comes from the till and is part of an underflow draining the ridge to the 

south. Water rises 6 inches above entering point.

69. Inclosed by four sections of 3J-foot tiling sunk into the ground. Water comes 

from the fine white sand probably resting on a ledge of gneisaoid granite. The yield 

to the bottling works is 5 gallons a minute, and the overflow is probably 10 gallons a 

minute, giving a total yield of about 15 gallons. The spring is located on a rather flat 

terrace at an elevation above the river of about 120 feet.

On the hillside, 200 yards away from the Arethusa Spring and at an elevation about 

25 or 30 feet higher, another spring issues from light-colored gneissoid granite, with the 

structure planes dipping about 4° SE. into the hillside. Both these springs maintain 

nearly the same flow throughout the year.

90. The water supply is obtained from three ponded areas located in a shallow 

valley and fed by springs. The topography is flat and the soil is porous. The run-off 

is accordingly small and the soil absorption large. The ground water is near the surface and emerges on a nearly level area at the contact of till and the thin overlying 

deposit of sand.

The following notes cover a few springs that are not listed in the 

table:

Granite Rock Spring, Higganum: This spring issues between two large granite 

bowlders on the upper slope of a high hill, but no rock outcrops are visible. The 

water is piped to a bottling works. The spring yields between 20,000 and 25,000 

gallons a day, with a fairly constant flow, at a temperature of 49° F. when the air 

temperature is 77°. The output of the bottling works during 1905 was about 50,000 

gallons. A second spring, recently excavated, is said to issue from a crevice oneeighth inch wide in the ledge.

Ausantowea Spring, Woodmont: Has been excavated to a depth of 20 feet through 

hardpan, sand, and gravel, the water horizon being in gravel. Flows 100 gallons 

an hour and varies little in yield with seasons. The temperature is 57° when the 

air temperature is 88°. The water is bottled and sold.

Buttress Dike Spring, Woodbridge: This "spring" is in reality a flowing well in 

which water rises 18 inches above the ground. It is on the side of a steep hill composed of chlorite schist and overlain by a thin layer of sandy till containing numerous 

heavy bowlders. The water appears to come from a vertical cleavage joint in the rock.

Springs of T. T. Wilcox, two-fifths of a mile southeast of Highland station: Three 

springs, two of which are reported by Mr. Wilcox to furnish 51 barrels a day, with no 

seasonal variation, at a temperature of 48° to 50° F. The only contributing area 

at a higher level than the spring is a hill with an elevation of less than 40 feet and 

covered with a thin layer of till. The water apparently reaches the surface by working along the bedding planes between sandstone and red shale. This requires a 

movement up a slope of about 15°.

Spring of Charles Parker, 1 mile southeast of Meriden: This spring is located on the 

west side of a hill composed of sandstone dipping southeast and capped with a thin 

covering of glacial drift. The water comes from joints in sandstone, as i-llustrated 

on page 136. The temperature of the water is 51° F. when the air temperature is 56°.

Chalybeate Spring, Litchfield: This interesting spring, which was famous in the 

early days of Connecticut, was described as follows by James Pierce: a "It issues 

from an extensive bed of sulphuret of iron, situated on the eastern side of Mount 

Prospect, 4 miles west of the village of Litchfield. The spring is copious and perennial, exhibiting in its course much oxide of iron and a white deposit."

a Am. Jour. Sci., vol. 3, 1821, p. 235.
BIBLIOGRAPHY.

The following is a list of papers dealing with Connecticut waters:

ELLIS, E. E. Occurrence of water in crystalline rocks. Water-Supply Paper U. S. 

Geol. Survey No. 160, 1906, pp. 19-28.

FULLER, M. L. Occurrence of underground waters of eastern United States. WaterSupply Paper U. S. Geol. Survey No. 114, 1905, pp. 17-40.

 Triassic rocks of the Connecticut Valley as a source of water supply. WaterSupply Paper U. S. Geol. Survey No. 110, 1904, pp. 95-112.

GREGORY, H. E. Connecticut [Occurrence of water]. Water-Supply Paper U. S. 

Geol. Survey No. 114, 1905, pp. 76-81.

GREGORY, H. E., CHAMPLIN, F. A., and GRANT, C.. L. Connecticut well and spring 

records. Water-Supply Paper U. S. Geol. Survey No. 102, 1904, pp. 127-168.

PYNCHON, W. H. C. Drilled wells of the Triassic area of the Connecticut Valley. 

Water-Supply Paper U. S. Geol. Survey No. 110, 1904, pp. 65-94.

RICE, W. N., and GREGORY, H. E. Manual of Connecticut geology. Bull. Connecticut Geol. and Nat. Hist. Survey No. 6, 1906. 

196
INDEX.

A.

Acknowledgments to those aiding........... 9

Artesian conditions, figures showing. 48,134,135,136 

nature of........................ 48-50,133-135

occurrence of............................ 96-97

Ausantowea Spring, description of........... 195

B.

Becket gneiss, character and distribution of.. 31

Bedding planes, occurrence and character

of............................. 107-108

water in............................... 108-109

Bibliography of Connecticut waters......... 196

Branford Point, coast near, map of.......... 163

coast near, water supply of............ 162-164

Buttress Dyke Spring, description of....... 96,195

C.

Chalybeate Spring, description of............ 195

Catchment basins, figures showing.......... 141

Chlorine, distribution of..................... 168

distribution of, map showing............ 168

Circulation. See Water.

Climate, description of...................... 20-27

Coast line, description of.................... 17

Coast region, town in, water supply of..... 162-164

Conglomerate, water in...................... 106

Connecticut River, flow of................... 29

Connecticut Valley, description of........... 17,19

Contamination, causes of.................... 53

Core drilling, description of.................. 183

Cream Hill, precipitation at................. 24

precipitation at, chart showing.......... 23

temperature at.......................... 25

Crystalline rocks, character and distribution

of...................... 3.5-37,54,56-60

distribution of, map showing............ 57

faults in................................. 38,65

joints in.-.......................... 37-38,61-64

literature of............................. 54-56

types of.............................. 54,56-59

water in............................. 37,54-103

circulation and storage of............ 65-77

conditions affecting................. 60-65

wells in................................ 92-103

contamination of.................. 173-174

depth of..................... 92-94,100-103

limit of.......................... 93-94

flow of.............................. 96-97

locating of................ 92,94-95,101-102

pollution of......................... 92

records of........................... 77-91

figures showing................. 77

notes on......................... 90-91

Crystalline rocks, wells in, success and failure of........................... 91-92

wells in, water of, analyses of............ 176

water of, quality of.......... 92,94,166,176

temperature of.................. 94

yield of............... 92-94,95-96,100-103

See also Igneous rocks; Metamorphic 

rocks; Granite; Gneiss, etc.

D.

Daubrfe, A., on ground water............... 55-56

Davis, W. M., on Connecticut geology...... 39-40

Drainage, description of..................... 17-20

Drift. See Pleistocene drift.

Drilled wells, construction of.............. 182-184

Drillings, character of....................... 59

Driven wells, construction of.............. 181-182

Dug wells, construction of................. 180-181

E. 

Elevations, data on................ 12,13,14,16,17

Ellis, E. E., on ground water in crystalline

rocks................--.-----.-. 54-103

on occurrence and recovery of ground

water........................... 4-1-53

work of................................. 9

Erosion, work of............................ 33-34

F.

Farmington River, description of........... 19

Farmington Valley, description of........... 15,17

Faults, figure showing...................... 114

occurrence and character of..... 33,38,41-42,65

relation of, to water............ 38,114-115,135

figure showing...................... 135

springs from............................ 187

Fissility, effect of, on ground water.......... 07

Flowing wells, occurrence and character

of....................... 9V97,133-135

view of..----------..-.--......--.---.--. 96

Forests, description of....................... 20

relation of, to run-off.................... 27-28

Fractures. Sec Joints.

Fuller, M. L., on artesian conditions........ 49-50

on ground water ........................ 53

on wells in trap....................... 129-130

G.

Gaylordsville, flow at....................... 29

Geography, description of................... ] 1-30

Geologic history, outline of.................. 31-34

Geologic map of Connecticut................ 57

197
198 INDEX.

Page. 

Geology, descriptive, account of............. 34-43

See also Crystalline rocks; Triassic rocks:

Pleistocene drift.

Glacial drift. See Pleistocene drift. 

Glaciation, topographic modeling by....... 11,34

Gneiss, character and distribution of.... 33-37,58

joints in................................. 98-99

water in................................. 37

wells in......................... 93-99,100-103

Gneissoid banding, nature of................ 63

Granite, character and distribution of....... 57-58

joints in................................. 64,9S

views of............................. 60

weathering of........................... 96

wells in......................... 97-98,100-103

Granite Rock Spring, description of......... 195

Granodiorite, joints in....................... 63-64

wells in............................... 100-103

Grant, C. L., well records by............... 88,126

Gregory, H.E., on wells in Connecticut...... 55

Gregory, H. E., and Rice, W. N., on Connecticut geology................. 32

Ground, humidity of^....................... 27

Ground water. See, Water, underground.

H. 

Hardness, causes of........................ 166-167

Hartford, flow at............................ 29

Highlands, description of..............'...... 12-16

rocks of................................. 32

streams of............................... 18

town of, water supply of.............. 157-160

History, geologic, outline of................. 31-34

Hobbs, \V. H., on joints..................... 63

on rivers of Connecticut................. 16

Holmes, J. A., on ground water............. 55

Hoosac schist, character and relations of..... 36,38

Housatonic River, fall on.................... 18

flow of.................................. 29

Housatonic Valley, description of........... 15,19

Humidity, records of........................ 25-27

I.

Ice. See Glaciation.

Igneous rocks, character and distribution of. 3n 

intrusion of............................. 31-32

water in................................. 1

Industries, data on.......................... 30

Intermittent springs, description of.......... 188

figure showing.......................... 188

J. 

Joints, continuity of......................... 66-67

direction of.......................... 63-64,132

intersection of......................... . G7-68

number if.... ........ ................. 70

occurrence and character of.. 37-38,40-41,01-64 

relation of, to water..................... 47-48,

65-70,100-114,141-142 

to water, figures showing.......... 135,136

to wells.............................. 93

figure showing................... 61

spacing of....................... 65-66,112-113

springs from............................. 187

views of............................. 60,62,106

width of............................. 69-70,113

water in, storage of...................... 74-76

See also Fissility; Schistosity; Triassic 

rocks; Crystalline rocks.

K. Page.

King, F. H., on ground water............... 51

L. 

Lakes, area of................................ 19

Lava, flows of............................... 16,33

flows of, occurrence and character of..... 38-40

Leakage, effect of, on water table............ 105

effect of, on water table, figure showing.. 105

Limestone, character and distribution of..... 59

distribution of, map showing............ 57

joints in............................. 64,99-100

wells in................................. 99-100

Long Island Sound, streams entering........ 18

Lowland, description of..................... 16-17

streams of............................... 19

town of, water supply of............... 160-162

M.

Map of Connecticut, showing distribution of

chlorine......................... 168

showing distribution of rocks............ 57

Marbje, character and distribution of........ 36

Metamorphic rocks, character and distribution of........................... 35-37

jointing in, view of...................... 62

Metamorphism, occurrence of................ 32

Mineral springs, nature of.................... 189

N.

Naugatuck Valley, description of............ 15

New Haven, humidity at.................... 25-26

precipitation at...................... 22-23,147

chart showing....................... 22

temperature at.......................... 25'

winds at................................. 26

water level at, fluctuations of............ 147

Nordenskiold, A. E., on wells in Sweden .... 56

Noroton Heights, flowing well at............ 97

flowing well at, view of.................. 96

North Haven, map of........................ 161

water supply of........................ 160-162

P.

Pegmatite, character and distribution of..... 59

Peneplain, formation of................. .... 33

Percival, J. G., on Connecticut topography.. 13 

Permeability, relation of, to wells........... 46-47

Phyllite, character and distribution of....... 36

wells in.................................. 99

Physiographic provinces, description of...... 12-17

map showing............................ 13

Pleistocene drift, analysis of................. 138

character of.................. 42-43,60,138-139

clay in.................................. 1401

contact of, vith rock.................... 142

water horizon at.................. 142-144

figures showing............... 142,143

grains in, size of......................... 140

stratification of....................... 139-140

water-holding capacity of................ 139

water in............................... 138-156

quality of........................... 145

storage of......................... 140-142

wells in............................... 142-143

cost of.-.-.---.....-...-.--.-..-.--.. 147

depthof........................... 144-145
INDEX. 199

Tage.

Pleistocene drift, wells in, figures showing. 142,143 

wells in, notes on...................... 151,156

pollution of.................-----. 172-173

records of................. 147-151,151-153

water in, analyses of................ 178

height of...................... 146-147

yield of........................... 144-145

See also Till; Stratified drift. 

Pleistocene epoch, land modeling in ........ 11,34

Population, data on......................... 30

Porosity, nature of.................... 45-46,60-61

Precipitation, amount of.................... 74

charts showing....................... 21,22,23

records of............................... 21-24

relation of, to water level.............. 146-147

Pynchon, W. H. C., on wells in trap...... 129-130

Quartzite, character and distribution of.. 36,58-59 

wells in............................ 99,100-103

Quinnebaug Valley, description of.......... 15

Quinnipiac Valley, description of........... 17

R. 

Railroads, routes of......................... 11-12

Rainfall. See Precipitation.

Rice, W. N., on Connecticut topography.... 14

Rice, W. N., and Gregory, H. E., on Connecticut geology...................... 32

Rocks, permeability of...................... 46-48

porosity of.............................. 46

relation of, to ground water............. 34

to jointing.......................... 62-63

to well digging...................... 34-35

Run-off, rate of............................. 28

relation of, to rainfall................... 27-28

S.

Saltonstall, Lake, water supply of........... 27

Sandstones, Triassic, distribution of, map

showing......................... 57

faults in, figure showing................. 114

water in............................ 114-115

joints in........................... 109-114

direction of...................... 112

spacing of..................... 112-113

view of.......................... 106

width of........................ 113

occurrence and character of.............. 39-40

quarries in.............................. 39

water in.............................:. 104-105

leaking of............................ 105

figure showing................... 105

quality of............................ 132

temperature of....................... 132

wells in................................ 115-128

contamination of.................... 173

depth of........................... 131-132

flow of............................. 133,135

locating of......................... 135-136

records of.................. 116-123,126-128

notes on................... 124-126,128

water in, analyses of................. 177

height of......................... 132

yield of........,................... 130-131

Page. 

Schist, character and distribution of......... 36,58

joints in................................. 98-99

views of............................. 62

water in................................. 37

wells in.......................... 98-99,100-103

Schistosity, effect of, on ground water....... 67

nature of................................ 63

Sea water, wells contaminated by.......... 92,174

. wells contaminated by, figure showing... 174 

Seepage, figure showing...................... 45

nature of................................ 45

Seepage springs, character of............... 185-186

Sewage, contamination by............. 171-174,182

Seyoms, G. H., work of.................. 9,169-170

Shale, water in.....................'....... 106-107

Shale, black, influence of, on water occurrence ........................... 39,109

position of............................... 39

Shetucket River, flow of..................... 28

Siphons, use of.............................. 95

Smith, G. O., on water in crystalline rocks... 55 

Smith, H. E., analyses by................... 9

Softness, causes of......................... 166-167

South Willington, well at, diagram of........ 143

Springs, conditions for...................... 49,185

conditions for, figure showing............ 50

fluctuations in.......................... 51,188

list of.................................... 190

notes on................................. 195

records of.............................. 190-194

relation of, to joints................ 135-136,187

figure showing....................... 136

types of......................... 50-51,185-187

figures showing..................... 50,136

water of, analyses of..................... 179

temperature of...................... 187

uses of............................. 189-190

volume of........................... 189

yield of.................................. 190

Steam boilers, water for................... 169-170

Still River, description of.................... 19

Stockbridge limestone, deposition of......... 31

Storrs, precipitation at...................... 21

precipitation at, chart showing.......... 21

temperature at.......................... 24

Stratified drift, character of................ 139-140

wells in, notes on........................ 156

records of.......................... 151-155

water from, analyses of.............. 178

Stratum springs, character of ............... 186-187

figure showing........................... 50

Streams, growth of, figure showing.......... 45

Structure planes, nature of.................. 63,67

Surface water supply. See Water supply,

surface. 

Swamps, areas of............................ 19

T.

Temperature, records of..................... 24-25

Thames Valley, description of............... 15

Tide, effect of, on water table............... 52,146

effect of, on water table, figure showing.. 51 

Till, wells in, notes on....................... 156

wells in, records of..................... 147-151

water of, analyses of................. 178
200 INDEX.

Page. 

Topography, description of.................. 11-17

formation of............................. 33-34

relation of, to water level................ 71-72

to water level, figure showing........ 71

to wells.................... 100-103,136-137

Trap, character and distribution of.......... 59

joints in................................. 113

view of.............................. 106

ridges of, formation of................... 33-34

wells in............................ 128-130

water in................................. 107

Triassic rocks, bedding planes in........... 107-108

bedding planes in, water in............ 108-109

character of.............................. 33

distribution of........................... 38

fossils in................................. 33

faults in................................. 41-42

water in........................... 114-115

joints in......................... 40-41,109-114

direction of.......................... 112

spacing of......................... 112-113

width of............................. 113

stratigraphy of.......................... 38-40

water in............................... 104-137

conditions of......................... 104

wells in................................ 115-130

records of.................. 116-123,126-128

figures showing................ 110, 111

notes on........... 124-126,128,129-130

See also Sandstone; Shale; Conglomerate;

Trap. 

Typhoid fever, cause of.................... 170-171

V. 

Valleys, descriptions of...................... 15-16

Van Hise, C. R., on ground water............ 54-55

W. 

Warren, map of............................. 158

water supply of........................ 157-160

Water, underground, amount of ............. 51,52

analyses of......................... 168,176-179

character of............................ 165-179

, circulation of...................... 44-51,72-74

decomposition by................... 73-74

direction of.......................... 72-73

figure showing....................... 45

composition of......................... 166-1C8

contamination of........... 53,165-168,170-175

Page. 

Water, underground, depth of..... 55,93-94,95-96

horizon of............................. 142-144

figures showing.................... 143,144

materials dissolved in................. 167-168

quality of........... 94,132,145,165,166,176,179

relation of, to geology.................... 34-35

storage of................................ 74-76

temperature of................... 52,94,133,187

uses of................................. 169-170

weathering by........................... 98

Water supply, surface, quantity available of. 28-29 

source and character of.................. 27-28

Water table, effect of leakage on............. 105

effect of leakage on, figure showing...... 105

effect of tide on.......................... 52

figure showing....................... 51

position of................. 44-45,70-72,146-147

figure showing....................... 143

relation of, to rainfall.................. 146-147

to topography....................... 70-71

figure showing................... 71

Wells, contamination of..................... 53,

92,165-168,170-175,180-184 

construction of.................... 172,180-184

depth of................................ 92-94,

100-103,131-132,136-137,144-145,172 

flow of........................... 96-97,133-135

fluctuations in.................. 52,92-94,95-96

locating of............ 92,94-95,135-136,171-172

pollution of.............................. 53,92

records of................................ 77-91

figures showing...................... 77

notes on............................. 90-91

relation of, to geology............. 34-35,97-100

to joints............................. 74-76

figure showing................... 61

to permeability of rocks............. 46-47

success and failure of.................... 91-92

water of, quality of.............. 92,94,116,176

temperature of...................... 52,94

water in, height of................. 133,143-144

quality of........................... 132

temperature of...................... 132

yield of........................... 74-76,92-94,

95-96,100-103,130-131,136-137,144-145 

Willimantic, flow at......................... 28

Willimantic Valley, description of........... 15

o