Prepared in cooperation with the Commonwealth of Massachusetts 

Office of the State Geologist and Executive Office of Energy and Environmental Affairs 

Surficial Geologic Map of the Heath-Northfield-SouthwickHampden 24-Quadrangle Area in the Connecticut Valley Region, 

West-Central Massachusetts 

Compiled by Janet R. Stone and Mary L. DiGiacomo-Cohen 

Open-File Report 2006-1260-G 

U.S. Department of the Interior 

U.S. Geological Survey 
ii

U.S. Department of the Interior 

KEN SALAZAR, Secretary 

U.S. Geological Survey 

Marcia K. McNutt, Director 

U.S. Geological Survey, Reston, Virginia: 2010 

For product and ordering information: 

World Wide Web: http://www.usgs.gov/pubprod 

Telephone: 1-888-ASK-USGS 

For more information on the USGS—the Federal source for science about the Earth, 

its natural and living resources, natural hazards, and the environment: 

World Wide Web: http://www.usgs.gov 

Telephone: 1-888-ASK-USGS 

Suggested citation: 

Stone, J.R., and DiGiacomo-Cohen, M.L., comps., 2010, Surficial geologic map of the Heath-Northfield-SouthwickHampden 24-quadrangle area in the Connecticut Valley region, west-central Massachusetts: U.S. Geological Survey 

Open-File Report 2006-1260-G. 

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report. 

Cover figure: A part of the surficial geologic map of the Mount Toby quadrangle, shown with semi-transparent 

shaded relief overlaid on the scanned topographic base map. Upper photograph by J.H. Hartshorn shows deltaic 

bedding in a gravel pit excavated into the Long Plain delta of glacial Lake Hitchcock; lower photograph by J.R. Stone 

shows summer silt layers (lighter) and winter clay layers (darker) in varved lake-bottom sediments of glacial Lake 

Hitchcock. 
iii

Contents 

Introduction .................................................................................................................................................................... 1

Surficial Materials in Massachusetts .............................................................................................................................. 2

Glacial till deposits ..................................................................................................................................................... 2

Glacial stratified deposits ........................................................................................................................................... 3

Postglacial deposits ................................................................................................................................................... 5

Description of Map Units ................................................................................................................................................ 5

Map Compilation ............................................................................................................................................................ 8 

References Cited ..........................................................................................................................................................12

Appendix: Sources of Data by 7.5-Minute Quadrangle .................................................................................................15

Figures 

1. Map showing general distribution of glacial and postglacial deposits in Massachusetts and map area of this report 2

2. Block diagram illustrating the typical areal and vertical distribution of glacial and postglacial deposits overlying 

bedrock ............................................................................................................................................................. 4

3. Grain-size classification used in this report. ............................................................................................................... 7

4. Index map showing 7.5-minute, 1:24,000-scale quadrangles in this compilation ..................................................... 10

5. Index map showing compilation areas in Massachusetts ........................................................................................ 11
iv

Conversion Factors 

Multiply By To obtain

Length 

inch (in.) 2.54 centimeter (cm) 

inch (in.) 25.4 millimeter (mm) 

foot (ft) 0.3048 meter (m) 

mile (mi) 1.609 kilometer (km) 

mile, nautical (nmi) 1.852 kilometer (km) 

yard (yd) 0.9144 meter (m) 

centimeter (cm) 0.3937 inch (in.) 

millimeter (mm) 0.03937 inch (in.) 

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi) 

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Area

square mile (mi2) 2.590 square kilometer (km2) 

square kilometer (km2) 0.3861 square mile (mi2) 
1

Surficial Geologic Map of the Heath-NorthfieldSouthwick-Hampden 24-Quadrangle Area in the 

Connecticut Valley Region, West-Central 

Massachusetts 

Compiled by Janet R. Stone and Mary L. DiGiacomo-Cohen 

Introduction 

The surficial geologic map layer shows the distribution of nonlithified earth materials at 

land surface in an area of 24 7.5-minute quadrangles (1,238 mi2 total) in west-central Massachusetts 

(fig. 1). Across Massachusetts, these materials range from a few feet to more than 500 ft in 

thickness. They overlie bedrock, which crops out in upland hills and as resistant ledges in valley 

areas. The geologic map differentiates surficial materials of Quaternary age on the basis of their 

lithologic characteristics (such as grain size and sedimentary structures), constructional geomorphic 

features, stratigraphic relationships, and age. Surficial materials also are known in engineering 

classifications as unconsolidated soils, which include coarse-grained soils, fine-grained soils, and 

organic fine-grained soils. Surficial materials underlie and are the parent materials of modern 

pedogenic soils, which have developed in them at the land surface. Surficial earth materials 

significantly affect human use of the land, and an accurate description of their distribution is 

particularly important for assessing water resources, construction aggregate resources, and earthsurface hazards, and for making land-use decisions. 

The mapped distribution of surficial materials that lie between the land surface and the 

bedrock surface is based on detailed geologic mapping of 7.5-minute topographic quadrangles, 

produced as part of an earlier (1938–1982) cooperative statewide mapping program between the 

U.S. Geological Survey and the Massachusetts Department of Public Works (now Massachusetts 

Highway Department) (Page, 1967; Stone, 1982). Each published geologic map presents a detailed 

description of local geologic map units, the genesis of the deposits, and age correlations among 

units. Previously unpublished field compilation maps exist on paper or mylar sheets and these have 

been digitally rendered for the present map compilation. Regional summaries based on the 

Massachusetts surficial geologic mapping studies discuss the ages of multiple glaciations, the 

nature of glaciofluvial, glaciolacustrine, and glaciomarine deposits, and the processes of ice 

advance and retreat across Massachusetts (Koteff and Pessl, 1981; papers in Larson and Stone, 

1982; Oldale and Barlow, 1986; Stone and Borns, 1986; Warren and Stone, 1986). 

This compilation of surficial geologic materials is an interim product that defines the areas 

of exposed bedrock and the boundaries between glacial till, glacial stratified deposits, and 

overlying postglacial deposits. This work is part of a comprehensive study to produce a statewide 

digital map of the surficial geology at a 1:24,000-scale level of accuracy. This surficial geologic 

map layer covering 24 quadrangles revises previous digital surficial geologic maps (Stone and 

others, 1993; MassGIS, 1999) that were compiled on base maps at regional scales of 1:125,000 and 
2

1:250,000. The purpose of this study is to provide fundamental geologic data for the evaluation of 

natural resources, hazards, and land information within the Commonwealth of Massachusetts. 

Figure 1. General distribution of glacial and postglacial deposits in Massachusetts (Stone and others, 1993; 

MassGIS, 1999) and 1:24,000-scale quadrangles covered by this report. 

Surficial Materials in Massachusetts

Most of the surficial materials in Massachusetts are deposits of the last two continental ice 

sheets that covered all of New England in the latter part of the Pleistocene ice age (Schafer and 

Hartshorn, 1965; Oldale and others, 1982; Stone and Borns, 1986). The glacial deposits are divided 

into two broad categories, glacial till and glacial stratified deposits. Till, the most widespread 

glacial deposit, was laid down directly by glacier ice. Glacial stratified deposits are concentrated in 

valleys and lowland areas and were laid down by glacial meltwater in streams, lakes, and the sea in 

front of the retreating ice margin during the last deglaciation. Postglacial sediments, primarily 

floodplain alluvium and swamp deposits, make up a lesser proportion of the unconsolidated 

materials. 

Glacial till deposits consist of nonsorted, generally nonstratified mixtures of mineral and 

rock particles ranging in grain size from clay to large boulders. The matrix of most tills is 

composed dominantly of fine sand and silt. Boulders, within and on the surface of tills, range from 

sparse to abundant. Some tills contain lenses of sorted sand and gravel, and less commonly, masses 

of laminated fine-grained sediments. The color and lithologic characteristics of till deposits vary 
3

across Massachusetts but generally reflect the composition of the local underlying and northerly 

adjacent bedrock, from which the till was derived. Till blankets the bedrock surface in variable 

thickness, ranging from a few inches to more than 200 ft, and commonly underlies stratified 

meltwater deposits. Tills deposited during the last two glaciations occur in superposition within 

Massachusetts (Koteff, 1966; Newton, 1978; Weddle and others, 1989). The upper till was 

deposited during the last (late Wisconsinan) glaciation; it is the most extensive till and commonly is 

observed in surface exposures, especially in areas where till thickness is less than 10 to 15 ft (thintill unit on the map). The lower till ("old" till) was deposited during an earlier glaciation (probably 

Illinoian). The lower till has a more limited distribution; it is principally a subsurface deposit that 

constitutes the bulk of material in drumlins and other hills, where till thickness is greater than 15 ft. 

The distribution of lower till is shown primarily by the thick-till unit on the map. The lower till 

generally is overlain by a thin mantle of upper till in these areas. In all exposures showing the 

superposed two tills, the base of the upper till truncates the weathered surface of the lower till. The 

lower part of the upper till commonly displays a zone of shearing, dislocation, and brecciation in 

which clasts of lower till were mixed and incorporated into the upper till during the last glaciation. 

End moraine deposits are composed predominantly of bouldery ablation till but also locally 

may include sorted sediments. These deposits were laid down by glacial-melting processes along 

active ice margins during retreat of the last (late Wisconsinan) ice sheet. Extensive end moraines on 

Nantucket and Martha’s Vineyard (fig. 1) are related to the terminal position of the lateWisconsinan ice sheet, and the end moraines on Cape Cod are associated with recessional positions 

of the last ice sheet. Less extensive end moraines occur locally elsewhere in southeastern 

Massachusetts, in the Boston area, and in the Gloucester-Rockport area of northeastern 

Massachusetts. 

Glacial stratified deposits consist of layers of well-sorted to poorly sorted gravel, sand, 

silt, and clay laid down by flowing meltwater in glacial streams, lakes, and marine embayments that 

occupied the valleys and lowlands of Massachusetts during retreat of the last ice sheet. Textural 

variations within the meltwater deposits occur both areally and vertically because meltwater-flow 

regimes were different in glaciofluvial (stream), glaciodeltaic (where a stream entered a lake or the 

sea), glaciolacustrine (lake bottom), and glaciomarine (marine bottom) depositional environments. 

Grain-size variations also resulted from meltwater deposition in positions either proximal to, or 

distal from, the retreating glacier margin, which was the principal sediment source. A common 

depositional setting contained a proximal, ice-marginal meltwater stream in which horizontally 

bedded glaciofluvial gravel and (or) sand and gravel were laid down; farther downvalley, the 

stream entered a glacial lake where glaciodeltaic sediments were deposited, consisting of 

horizontally layered sand and gravel delta-topset beds overlying inclined layers of sand in deltaforeset beds. Farther out in the glacial lake, very fine sand, silt, and clay settled out on the lake 

bottom in flat-lying, thinly bedded glaciolacustrine layers. Thick sequences having these textural 

variations commonly are present in the vertical section of meltwater deposits across the State 

(Stone and others, 1992). Most of the meltwater sediments in Massachusetts were deposited in or 

graded to large and small glacial lakes. These large and small lakes formed in northerly sloping 

valleys and basins where they were dammed by the ice margin (ice-dammed lakes) and in southerly 

sloping valleys and basins where they were dammed by slightly earlier deltaic sediments 

(sediment-dammed lakes). The largest glacial lake in Massachusetts was an extensive sedimentdammed lake (glacial Lake Hitchcock) which occupied the Connecticut Valley area at altitudes 

below 365 ft during the retreat of the last ice sheet. Lake Hitchcock was dammed behind a mass of 
4

earlier deltaic sediments in the Cromwell-Rocky Hill area of central Connecticut, and the lake 

lengthened northward into northern Vermont and New Hampshire as the ice sheet retreated. 

Detailed geologic maps can show meltwater sedimentary units within each glacial lake or 

valley outwash system (Jahns, 1941, 1953; Koteff, 1966). These units, known as morphosequences

(Koteff, 1974; Koteff and Pessl, 1981), are the smallest mappable stratigraphic units depictable on 

detailed geologic maps. Morphosequences are bodies of stratified meltwater sediments that are 

contained in a continuum of landforms, grading from ice-contact forms (eskers, kames) to non-icecontact forms (flat valley terraces, delta plains) that were deposited simultaneously at and beyond 

the margin of the ice sheet, and were graded to a specific base level. Each morphosequence consists 

of a proximal part (head) deposited within or near the ice margin and a distal part deposited farther 

away from the ice margin. Both grain size and ice-melt collapse deformation of beds decrease from 

the proximal to the distal part of each morphosequence. The head of each morphosequence is either 

ice marginal (ice contact) or near ice marginal. The surface altitude of fluvial sediments in each 

morphosequence was controlled by a specific base level, either a glacial-lake or marine water plane 

or a valley knickpoint. Few morphosequences extend distally more than 6 miles, and most are less 

than a mile in length. In any one basin, individual morphosequences were deposited sequentially as 

the ice margin retreated systematically northward. Consequently, in many places the distal, finer 

grained facies of a younger morphosequence stratigraphically overlies the proximal, coarse-grained 

facies of a preceding morphosequence. 

Figure 2 shows an example of the variability of sediment types in the subsurface of glacial 

stratified deposits. The figure schematically shows the relationship between coarse-grained deltaic 

deposits (sand and gravel and sand) and extensive fine-grained lake (or marine) deposits (fine sand, 

silt, and clay) in the subsurface. Such coarse- and fine-grained units are common in most of the 

valleys and lowlands of Massachusetts (Langer, 1979; Stone and others, 1979; Stone and others, 

1992; Stone and others, 2005). On these interim maps, coarse-grained and fine-grained textural 

variations within glacial stratified deposits are shown only where they occur at land surface. 

Subsurface textural variations are not shown. 

Figure 2. Block diagram illustrating the typical areal and vertical distribution of glacial and postglacial 

deposits overlying bedrock (modified from Stone and others, 1992). 
5

The areal distribution of till and stratified deposits is related to the physiography of the State 

(fig. 1). The thickness of these materials varies considerably within these regions because of such 

factors as the high relief of the bedrock surface, changing environments of deposition during 

deglaciation, and various effects of postglacial erosion and removal of glacial sediments. In 

highland areas, notably in the western and central regions, till is the major surficial material and is 

present as a discontinuous mantle of variable thickness over the bedrock surface. Till is thickest in 

drumlins (reportedly as much as 230 ft thick) and on the northwest slopes of most bedrock hills. 

Glacial meltwater deposits that average 50 ft in thickness (Stone and others, 1993) overlie the till in 

small upland valleys and north-sloping basins between bedrock hills. Glacial stratified deposits are 

the predominant surficial materials in the Connecticut River valley, the northeastern and 

southeastern lowlands, and on Cape Cod and the islands. These deposits generally overlie till; 

however, well logs indicate that in some places till is not present and the stratified deposits lie 

directly on bedrock. On Cape Cod and the islands, in the southeastern lowland, and in parts of the 

Connecticut River valley, these deposits completely cover the till-draped bedrock surface. 

Postglacial deposits locally overlie the glacial deposits throughout the State. Alluvium 

underlies the floodplains of most streams and rivers. Swamps occur in low-lying, poorly drained 

areas in upland and lowland settings, but swamp deposits are shown only where they are estimated 

to be at least 3 ft thick. Salt-marsh and estuarine deposits are present mainly along the tidal portions 

of streams and rivers entering the offshore areas. Beach and dune deposits occur along the 

shoreline.

Description of Map Units

Postglacial Deposits 

Artificial fill—Earth materials and manmade materials that have been artificially 

emplaced, primarily in highway and railroad embankments, and in dams; may also 

include landfills, urban development areas, and filled coastal wetlands 

Floodplain alluvium—Sand, gravel, silt, and some organic material, stratified and 

well sorted to poorly sorted, beneath the floodplains of modern streams. The texture 

of alluvium commonly varies over short distances, both laterally and vertically, and 

generally is similar to the texture of adjacent glacial deposits. Along smaller 

streams, alluvium is commonly less than 5 ft thick. The most extensive deposits of 

alluvium on the map are along the Connecticut, Deerfield, Westfield, and Chicopee 

Rivers, where the texture is predominantly sand, fine gravel, and silt, and total 

thickness is as much as 25 ft. Alluvium typically overlies thicker glacial stratified 

deposits 

Swamp deposits—Organic muck and peat that contain minor amounts of sand, silt, 

and clay, stratified and poorly sorted, in kettle depressions or poorly drained areas. 

Swamp deposits are shown only where they are estimated to be at least 3 ft thick. 
6

Most swamp deposits are less than 10 ft thick. Swamp deposits overlie glacial 

deposits or bedrock. They locally overlie glacial till even where they occur within 

thin glacial meltwater deposits 

Early Postglacial Deposits 

Alluvial-fan deposits—Generally coarse gravel and sand deposits on steep slopes 

where high gradient streams entered lower gradient valleys. Some alluvial fans in 

this area were graded to lowering levels of glacial Lake Hitchcock. Some fans 

continue to form today 

Stream-terrace deposits—Sand, gravel, and silt deposited by meteoric water 

(locally distal meltwater) on terraces cut into glacial meltwater sediments along 

rivers and streams. Most stream-terrace deposits are less than 10 ft thick and overlie 

thicker glacial deposits; textures are usually similar to underlying glacial meltwater 

deposits. Many stream terraces in the Connecticut River valley are composed of fine 

to medium sand and overlie lake-bottom silt and clay 

 

Inland-dune deposits—Fine to medium, well-sorted sand in transverse, parabolic, 

and hummocky dunes as much as 60 ft thick. Deposits occur chiefly in the glacial 

Lake Hitchcock basin where sand derived from extensive glacial-lake deltas that 

were not yet vegetated was deposited in dune forms by early postglacial winds. 

Dune sand is now fixed by vegetation except where disturbed by human activities 

 

Talus deposits—Angular, loose blocks of basalt and diabase accumulated by 

rockfall and creep at the base of bedrock cliffs along linear traprock ridges in the 

Mesozoic lowland. Talus deposits form steep, unstable slopes. Generally less than 

20 ft thick 

Glacial Stratified Deposits 

Sorted and stratified sediments composed of gravel, sand, silt, and clay (as defined in 

particle-size diagram, fig. 3) deposited in layers by glacial meltwater. These sediments occur as 

four basic textural units—gravel deposits, sand and gravel deposits, sand deposits, and fine 

deposits. On this interim surficial geologic map layer, gravel, sand and gravel, and sand deposits 

are not differentiated and are shown as Coarse Deposits where they occur at land surface. Fine 

Deposits also are shown where they occur at land surface. Textural changes occur both areally and 

vertically (fig. 2); however, subsurface textural variations are not shown on this interim map. 
7

PARTICLE DIAMETER 

10 2.5 .16 .08 .04 .02 .01 .005 .0025 .00015 inches 

256 64 4 2 1 .5 .25 .125 .063 .004 mm 

Boulders Cobbles Pebbles Granules 

Very 

coarse 

sand 

Coarse 

sand 

Medium 

sand 

Fine 

sand 

Very fine 

sand Silt Clay 

GRAVEL PARTICLES SAND PARTICLES FINE PARTICLES 

Figure 3. Grain-size classification used in this report, modified from Wentworth (1922). 

Coarse deposits include Gravel deposits composed of at least 50 percent gravel-size 

clasts; cobbles and boulders predominate; minor amounts of sand occur within 

gravel beds, and sand comprises few separate layers. Gravel layers generally are 

poorly sorted, and bedding commonly is distorted and faulted due to 

postdepositional collapse related to melting of ice. Sand and gravel deposits occur 

as mixtures of gravel and sand within individual layers and as layers of sand 

alternating with layers of gravel. Sand and gravel layers generally range from 25 to 

50 percent gravel particles and from 50 to 75 percent sand particles. Layers are well 

to poorly sorted; bedding may be distorted and faulted due to postdepositional 

collapse. Sand deposits are composed mainly of very coarse to fine sand, commonly 

in well-sorted layers. Coarser layers may contain up to 25 percent gravel particles, 

generally granules and pebbles; finer layers may contain some very fine sand, silt, 

and clay 

Fine deposits include very fine sand, silt, and clay that occur as well-sorted, thin 

layers of alternating silt and clay (varves), or as thicker layers of very fine sand and 

silt. Very fine sand commonly occurs at the surface and grades downward into 

rhythmically bedded silt and clay varves. In some places on the lake-bottom surface 

of glacial Lake Hitchcock, fine deposits are overlain by as much as 30 ft of fine to 

medium sand, deposited as the lake lowered; this sand has not been mapped 

separately 

Glacial Till Deposits 

Thin till—Nonsorted, nonstratified matrix of sand, some silt, and little clay 

containing scattered pebble, cobble, and boulder clasts; large surface boulders are 

common; mapped where till is generally less than 10 to 15 ft thick including areas of 

shallow bedrock. Predominantly consists of upper till of the last glaciation; loose to 

moderately compact, generally sandy, commonly stony. Two facies are present in 

some places: a looser, coarser grained ablation facies, melted out from supraglacial 
8

position; and an underlying more compact, finer grained lodgement facies deposited 

subglacially. In general, both ablation and lodgement facies of upper till derived 

from fine-grained bedrock are finer grained, more compact, less stony and have 

fewer surface boulders than upper till derived from coarse-grained crystalline rocks. 

Fine-grained bedrock sources include the red Mesozoic sedimentary rocks of the 

Connecticut River lowland, marble in the western river valleys, and fine-grained 

schists in upland areas 

Thick till—Nonsorted, nonstratified matrix of sand, some silt, and little clay 

containing scattered pebbles, cobbles, and boulders in the shallow subsurface; at 

greater depths consists of compact, nonsorted matrix of silt, very fine sand, and 

some clay containing scattered small gravel clasts. Mapped in areas where till is 

greater than 10 to 15 ft thick, chiefly in drumlin landforms in which till thickness 

commonly exceeds 100 ft (maximum recorded thickness is 230 ft). Although upper 

till is the surface deposit, the lower till constitutes the bulk of the material in these 

areas. Lower till is moderately to very compact and is commonly finer grained and 

less stony than upper till. An oxidized zone, the lower part of a soil profile formed 

during a period of interglacial weathering, is generally present in the upper part of 

the lower till. This zone commonly shows closely spaced joints that are stained with 

iron and manganese oxides 

Bedrock Areas 

Bedrock outcrops and areas of abundant outcrop or shallow bedrock—Solid 

color shows extent of individual bedrock outcrops; stipple pattern indicates areas of 

shallow bedrock or areas where small outcrops are too numerous to map 

individually; in areas of shallow bedrock, surficial materials are less than 5 to 10 ft 

thick. These units are not mapped consistently among all quadrangles; see Appendix

for level of bedrock outcrop mapping in each quadrangle 

Map Compilation 

This compilation is the sixth in a series of interim products and shows surficial geology in 

an area of 24 7.5-minute quadrangles in the Connecticut Valley region of west-central 

Massachusetts. The quadrangles are Heath, Colrain, Bernardston, Northfield, Ashfield, Shelburne 

Falls, Greenfield, Millers Falls, Goshen, Williamsburg, Mount Toby, Shutesbury, Westhampton, 

Easthampton, Mount Holyoke, Belchertown, Woronoco, Mount Tom, Springfield North, Ludlow, 

Southwick, West Springfield, Springfield South, and Hampden (fig. 4; fig. 5, area G). Figure 5 

shows all of the compilation areas for surficial geology in Massachusetts. The surficial geologic 

maps are being produced sequentially by letter designation (although publication of area G 

precedes that of area F). 

The surficial geologic map layer was compiled in several steps: 
9

1) Paper copies of the published surficial geologic maps for 15 quadrangles were scanned 

and georeferenced by MassGIS; 

2) The Office of the Massachusetts State Geologist vectorized the georeferenced images in 

order to digitally retain the original linework of the published maps (Mabee and others, 

2004); 

3) Digital geologic map units were compiled and grouped into basic units in four shapefile 

layers: Postglacial deposits including artificial fill, swamp deposits, and floodplain 

alluvium; early postglacial deposits including alluvial-fan, stream-terrace, inland-dune, 

and talus deposits; glacial stratified deposits including coarse-grained and fine-grained 

deposits; and glacial till and bedrock including thin till, thick till (drumlins), outcrops and 

areas of shallow bedrock. The distribution of glacial stratified deposits beneath adjacent 

overlying postglacial deposits and water bodies was inferred by the compilers; 

4) The same basic units as those listed above were compiled and digitized for 9 unpublished 

quadrangles from scanned field maps by U.S. Geological Survey personnel; 

5) The 24 individual quadrangle maps were joined and edge-matched in order to form a 

seamless digital geologic map layer. Discrepancies along quadrangle boundaries were 

resolved, and thick-till areas and shallow bedrock areas were added by the compilers in 

quadrangles where these units had not been previously mapped. 
10

 

Figure 4. The 24 USGS 7.5-minute, 1:24,000-scale quadrangles in this compilation. Sheet numbers refer to 

Adobe PDF map files of individual quadrangles. 
11

All geologic mapping was completed at 1:24,000 scale (several quadrangles were 

previously published at 1:31,680 scale). The 1:24,000-scale, 10-ft (and 20-ft) contour interval 

topographic base maps (1958–1977 editions) used for this mapping effort are included as part of 

the digital data package in the 24k_basemaps folder. The GIS folder included with this report 

contains four ArcGIS shapefiles, which show the distribution of geologic units that cover the entire 

map area and are intended for use at quadrangle scale. The shapefiles can be clipped by quadrangle 

or by town boundary. Unlike the units in conventional geologic maps, the digitally defined map 

units are arranged in layers according to superposition. The shapefile for till and bedrock is the 

bottom layer, which is overlain by the succeeding stratified deposits shapefile layer; these materials 

are shown everywhere they occur, including beneath postglacial and early postglacial deposits such 

as swamp deposits and stream-terrace deposits, and also beneath water bodies. The postglacial 

shapefile should be placed on top because these materials overlie the other three layers. Instructions 

for using the digital files are included in the README file and metadata. 

In addition to the seamless digital layers that cover the entire compilation area, Adobe PDF 

map files of the surficial geology layers shown with 1:24,000-scale topographic base map images 

have been generated for each quadrangle (see Sheets 1–24, fig. 4). 

Figure 5. Compilation areas in Massachusetts. Letters represent sections of Open-File Report 2006-

1260. Sections published to date are available online at http://pubs.usgs.gov/of/2006/1260/.
12

References Cited 

Balk, Robert, 1956a, Bedrock geology of the Massachusetts portion of the Bernardston quadrangle, 

Massachusetts-Vermont: U.S. Geological Survey Geologic Quadrangle Map GQ–90, scale 

1:31,680. 

Balk, Robert, 1956b, Bedrock geology of the Millers Falls quadrangle, Massachusetts: U.S. 

Geological Survey Geologic Quadrangle Map GQ–93, scale 1:31,680. 

Balk, Robert, 1957, Geology of the Mount Holyoke quadrangle, Massachusetts: Geological Society 

of America Bulletin, v. 68, no. 4, p. 481–504, map scale 1:31,680. 

Caggiano, J.A., Jr., 1978, Surficial and applied surficial geology of the Belchertown quadrangle, 

Massachusetts: Amherst, Mass., University of Massachusetts, Ph.D. dissertation, 238 p. 

Campbell, K.J., and Hartshorn, J.H., 1980, Surficial geologic map of the Northfield quadrangle, 

Massachusetts, New Hampshire, and Vermont: U.S. Geological Survey Geologic Quadrangle 

Map GQ–1440, 1 sheet, scale 1:24,000.

Clark, S.F., Jr., 1987, Bedrock geologic map of the Westhampton quadrangle, Hampshire County, 

Massachusetts: U.S. Geological Survey Geologic Quadrangle Map GQ–1640, 1 sheet, scale 

1:24,000. 

Colton, R.B., and Hartshorn, J.H., 1970, Surficial geologic map of the West Springfield 

quadrangle, Massachusetts and Connecticut: U.S. Geological Survey Geologic Quadrangle Map 

GQ–892, scale 1:24,000. 

Hartshorn, J.H., and Koteff, Carl, 1967, Geologic map of the Springfield South quadrangle, 

Hampden County, Massachusetts, and Hartford and Tolland Counties, Connecticut: U.S. 

Geological Survey Geologic Quadrangle Map GQ–678, scale 1:24,000. 

Hatch, N.L., Jr., and Hartshorn, J.H., 1968, Geologic map of the Heath quadrangle, MassachusettsVermont: U.S. Geological Survey Geologic Quadrangle Map GQ–735, scale 1:24,000. 

Hatch, N.L., Jr., 1981, Reconnaissance bedrock geologic map of the Ashfield quadrangle, Franklin 

County, Massachusetts: U.S. Geological Survey Miscellaneous Field Studies Map MF–855, 1 

sheet, scale 1:24,000. 

Hatch, N.L., Jr., and Warren, C.R., 1982, Geologic map of the Goshen quadrangle, Franklin and 

Hampshire Counties, Massachusetts: U.S. Geological Survey Geologic Quadrangle Map GQ–

1561, 1 sheet, scale 1:24,000. 

Hildreth, C.T., and Colton, R.B., 1982, Surficial geologic map of the Hampden quadrangle, 

Massachusetts and Connecticut: U.S. Geological Survey Geologic Quadrangle Map GQ–1544, 1 

sheet, scale 1:24,000. 

Jahns, R.H, 1941, Outwash chronology in northeastern Massachusetts [abs.]: Geological Society of 

America Bulletin, v. 52, no. 12, pt. 2, p. 1910. 

Jahns, R.H, 1951, Surficial geology of the Mount Toby quadrangle, Massachusetts: U.S. 

Geological Survey Geologic Quadrangle Map GQ–9, scale 1:31,680. 

Jahns, R.H, 1953, Surficial geology of the Ayer quadrangle, Massachusetts: U.S. Geological 

Survey Geologic Quadrangle Map GQ–21, scale 1:31,680. 

Jahns, R.H, 1966, Surficial geologic map of the Greenfield quadrangle, Massachusetts: U.S. 

Geological Survey Geologic Quadrangle Map GQ–474, scale 1:24,000. 

Koteff, Carl, 1966, Surficial geologic map of the Clinton quadrangle, Worcester County, 

Massachusetts: U.S. Geological Survey Geologic Quadrangle Map GQ–567, scale 1:24,000. 

Koteff, Carl, 1974, The morphologic sequence concept and deglaciation of southern New England, 

in Coates, D.R., ed., Glacial geomorphology: Binghamton, N.Y., State University of New York, 

Annual Geomorphology Symposia Series, Proceedings, v. 5, p. 121–144. 
13

Koteff, Carl, and Pessl, Fred, Jr., 1981, Systematic ice retreat in New England: U.S. Geological 

Survey Professional Paper 1179, 20 p. 

Langer, W.H., 1979, Map showing distribution and thickness of the principal fine-grained deposits, 

Connecticut Valley urban area, central New England: U.S. Geological Survey Miscellaneous 

Investigations Series Map I–1074–C, 2 sheets, scale 1:125,000. 

Larsen, F.D., 1972, Surficial geology of the Mount Tom quadrangle, Massachusetts, U.S. 

Geological Survey Open-File Report OF–72–219, 273 p., 4 map sheets, scale 1:24,000. 

Larson, G.J., and Stone, B.D., eds., 1982, Late Wisconsinan glaciation of New England: Dubuque, 

Iowa, Kendall/Hunt, 252 p. 

Leo, G.W., 1974, Map showing unconsolidated materials, Ludlow quadrangle, Massachusetts: U.S. 

Geological Survey Miscellaneous Field Studies Map MF–503–C, scale 1:24,000. 

Mabee, S.B., Stone, B.D., and Stone, J.R., 2004, Precise conversion of paper geologic maps to 

value-added digital products; the Massachusetts method for surficial geology: Geological Society 

of America Abstracts with Programs, v. 36, no. 2, p. 78. 

MassGIS (Massachusetts Office of Geographic Information), 1999, Surficial geology (1:250,000), 

October 1999 [statewide data layer]: Vector digital data available at 

http://www.mass.gov/mgis/sg.htm. 

Newton, R.M., 1978, Stratigraphy and structure of some New England tills: Amherst, Mass., 

University of Massachusetts, unpublished Ph.D. dissertation, 256 p. 

Oldale, R.N., and Barlow, R.A., 1986, Geologic map of Cape Cod and the Islands, Massachusetts: 

U.S. Geological Survey Miscellaneous Investigations Series Map I–1763, 1 sheet, scale 

1:100,000. 

Oldale, R.N., Valentine, P.C., Cronin, T.M., Spiker, E.C., Blackwelder, B.W., Belknap, D.F., 

Wehmiller, J.F., and Szabo, B.J., 1982, Stratigraphy, structure, absolute age, and paleontology of 

the upper Pleistocene deposits at Sankaty Head, Nantucket Island, Massachusetts: Geology, v. 

10, no. 5, p. 246–252. 

Page, L.R., 1967, The role of the United States Geological Survey in Massachusetts, in Farquhar, 

O.C., ed., Economic geology in Massachusetts: Amherst, Mass., University of Massachusetts, p. 

9–28. 

Retelle, M.J., 1979, Surficial geology of the southern half of the Bernardston quadrangle, 

Massachusetts and Vermont: Amherst, Mass., University of Massachusetts, unpublished M.S. 

thesis, 98 p. 

Schafer, J.P., and Hartshorn, J.H., 1965, The Quaternary of New England, in Wright, H.E., Jr., and 

Frey, D.G., eds., The Quaternary of the United States: Princeton, N.J., Princeton University 

Press, p. 113–128. 

Schnabel, R.W., 1971, Surficial geologic map of the Southwick quadrangle, Massachusetts and 

Connecticut: U.S. Geological Survey Geologic Quadrangle Map GQ–891, scale 1:24,000. 

Segerstrom, Kenneth, 1955a, Surficial geology of the Colrain quadrangle, Massachusetts-Vermont: 

U.S. Geological Survey Geologic Quadrangle Map GQ–82, scale 1:31,680. 

Segerstrom, Kenneth, 1955b, Surficial geology of the Williamsburg quadrangle, Massachusetts: 

U.S. Geological Survey Geologic Quadrangle Map GQ–80, scale 1:31,680. 

Segerstrom, Kenneth, 1959, Surficial geology of the Shelburne Falls quadrangle, Massachusetts: 

U.S. Geological Survey Geologic Quadrangle Map GQ–116, scale 1:31,680. 

Stanley, R.S., Clark, S.F., Jr., and Hatch, N.L., Jr., 1982, Bedrock geologic map of the Woronoco 

quadrangle, Hampden and Hampshire Counties, Massachusetts: U.S. Geological Survey 

Geologic Quadrangle Map GQ–1565, 1 sheet, scale 1:24,000. 
14

Stone, B.D., 1982, The Massachusetts State surficial geologic map, in Farquhar, O.C., ed., 

Geotechnology in Massachusetts: Boston, University of Massachusetts, p. 11–28. 

Stone, B.D., Beinikis, A.I., and Foster, Richard, 1993, Sand and gravel resources of Massachusetts: 

Boston, Massachusetts, New England Governors' Conference, 2 map sheets, scale 1:250,000. 

Stone, B.D., and Borns, H.W., Jr., 1986, Pleistocene glacial and interglacial stratigraphy of New 

England, Long Island, and adjacent Georges Bank and Gulf of Maine, in Sibrava, Vladimir, 

Bowen, D.Q., and Richmond, G.M., eds., Quaternary glaciations in the Northern Hemisphere: 

Quaternary Science Reviews, v. 5, p. 39–52. 

Stone, J.R., 1978, Preliminary map of surficial deposits in the Shutesbury quadrangle, 

Massachusetts: U.S. Geological Survey Open-File Report OF–78–285, 7 p. and 1 map sheet, 

scale 1:24,000. 

Stone, J.R., London, E.H., and Langer, W.H., 1979, Map showing textures of unconsolidated 

materials, Connecticut Valley urban area, central New England: U.S. Geological Survey 

Miscellaneous Investigations Series Map I–1074–B, 3 sheets, scale 1:125,000. 

Stone, J.R., Schafer, J.P., London, E.H., and Thompson, W.B., 1992, Surficial materials map of 

Connecticut: U.S. Geological Survey Special Map, 2 sheets, scale 1:125,000. 

Stone, J.R., Schafer, J.P., London, E.H., DiGiacomo-Cohen, M.L., Lewis, R.L., and Thompson, 

W.B., 2005, Quaternary geologic map of Connecticut and Long Island Sound basin: U.S. 

Geological Survey Scientific Investigations Map 2784, 2 sheets, scale 1:125,000, 72-p. pamphlet. 

Warren, C.R., and Stone, B.D., 1986, Deglaciation stratigraphy, mode and timing of the eastern 

flank of the Hudson-Champlain lobe in western Massachusetts, in Cadwell, D.H., ed., The 

Wisconsinan Stage of the First Geological District, eastern New York: New York State Museum 

Bulletin, v. 455, p. 168–192. 

Weddle, T.K., Stone, B.D., Thompson, W.B., Retelle, M.J., Caldwell, D.W., and Clinch, J.M., 

1989, Illinoian and late Wisconsinan tills in eastern New England; transect from northeastern 

Massachusetts to west-central Maine, Trip A-2, in Berry, A.W., Jr., ed., Guidebook for field trips 

in southern and west-central Maine: New England Intercollegiate Geological Conference, 81st

Annual Meeting, p. 25–85. 

Wentworth, C.K., 1922, A scale of grade and class terms for clastic sediments: Journal of Geology, 

v. 30, no. 5, p. 377–392. 
15

Appendix 

Sources of Data by 7.5-Minute Quadrangle 

Heath Quadrangle 

Map units were reproduced from Hatch and Hartshorn (1968). Glacial Stratified Deposits include 

predominantly coarse-grained glaciofluvial and glaciodeltaic sediments graded to small glacial 

lakes in the Deerfield River, West Branch North River, and Mill Brook valleys. Thick-till areas 

were delineated based on topographic analysis. The shallow bedrock unit represents areas of 

abundant outcrop but is shown only where the bedrock mapper made structural measurements. 

Some areas of shallow bedrock were added to those shown on the published map using topographic 

analysis, but significant additional areas of shallow bedrock and bedrock outcrops occur, 

particularly in areas of thin till that have steep slopes and irregular topography. Some postglacial 

units were mapped using 2005 orthophoto images. 

Colrain Quadrangle 

Map units were modified from Segerstrom (1955a). Glacial Stratified Deposits include 

predominantly coarse-grained glaciofluvial and glaciodeltaic sediments graded to small glacial 

lakes in the Green River, Hinsdale Brook, and North River valleys and several tributary valleys. 

Coarse- and fine-grained deposits of glacial Lake Hitchcock occur in the southeast corner of the 

quadrangle. Bedrock outcrops were mapped mainly in areas of glacial stratified deposits. The 

shallow-bedrock unit is slightly modified from the Qgm (thin ground moraine) unit of Segerstrom 

(1955a), which is defined as “thin deposits of ground moraine (till) with many exposures of 

bedrock;” this unit is more extensive than in other quadrangles and is probably overmapped. The 

thick-till unit is slightly modified from the Qgd (drumlins) unit and includes some areas within the 

Qgt unit of Segerstrom (1955a). Additional areas of thick till may be expected in places not 

mapped as shallow bedrock, particularly beneath smooth slopes on the northerly sides of bedrock 

hills. Some postglacial units were mapped using 2005 orthophoto images.

Bernardston Quadrangle 

Stone, J.R., 1975, unpublished field map; Larsen, F.D., 1977, unpublished field map. Mapping in 

part based on an unpublished M.S. thesis by Retelle (1979). Glacial Stratified Deposits include 

coarse- and fine-grained deposits of glacial Lake Hitchcock in the Green River, Fall River, and 

Connecticut River valleys, and deposits of local higher level lakes. Distribution of bedrock 

outcrops and shallow-bedrock areas is from Balk (1956a). The shallow-bedrock unit represents 

areas of small scattered bedrock outcrops. Some postglacial units were mapped using 2005 

orthophoto images. 
16

Northfield Quadrangle 

Map units were reproduced from Campbell and Hartshorn (1980). Glacial Stratified Deposits are 

predominantly coarse- and fine-grained deposits of glacial Lake Hitchcock in the Connecticut River 

valley. Thick-till areas were mapped based on topographic analysis and the position of drumlin 

axes shown on the map of Campbell and Hartshorn (1980). The shallow-bedrock unit represents 

areas of thin surficial deposits and numerous bedrock outcrops. 

 

Ashfield Quadrangle 

Hartshorn J.H., 1975, unpublished field map. Glacial Stratified Deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments graded to small glacial lakes in the 

Deerfield River, Clesson Brook, and South River valleys. Distribution of bedrock outcrops and 

some shallow-bedrock areas is from Hatch (1981). Additional shallow-bedrock areas were 

interpreted from topographic analysis. Some postglacial units were mapped using 2005 orthophoto 

images. 

Shelburne Falls Quadrangle 

Map units were modified from Segerstrom (1959). Glacial Stratified Deposits include 

predominantly coarse-grained glaciofluvial and glaciodeltaic sediments graded to small icedammed glacial lakes in the South River, Bear River, and Deerfield River valleys. Coarse- and 

fine-grained deposits of glacial Lake Hitchcock occur in the eastern part of the quadrangle. 

Bedrock outcrops are mapped mainly in areas of glacial stratified deposits. The shallow-bedrock 

unit is modified from the Qgm (thin ground moraine) unit of Segerstrom (1959), which is defined 

as “thin deposits of ground moraine (till) with many exposures of bedrock;” this unit is more 

extensive than in other quadrangles and is probably overmapped. The thick-till unit is modified 

from the Qgd (drumlins) unit of Segerstrom (1959). Additional areas of thick till may be expected 

in places not mapped as shallow bedrock, particularly beneath smooth slopes on the northerly sides 

of bedrock hills. 

Greenfield Quadrangle 

Map units were reproduced from Jahns (1966). Glacial Stratified Deposits are predominantly 

coarse- and fine-grained deposits of glacial Lake Hitchcock in the Green River, Deerfield River, 

and Connecticut River valleys; other glaciofluvial and glaciolacustrine deposits graded to higher 

level ice-dammed lakes occur in tributary valleys. The shallow-bedrock unit is modified from the 

Qgm (thin ground moraine) unit of Jahns (1966), which is defined as “generally thin deposits of 

ground moraine (till) with many exposures of bedrock.” The thick-till unit is modified from the 

Qgd (drumlins) unit of Jahns (1966). Additional areas of thick till may be expected in places not 

mapped as shallow bedrock, particularly beneath smooth slopes on the northerly sides of bedrock 

hills. 
17

Millers Falls Quadrangle 

Stone, J.R., 1975, unpublished field map. Glacial Stratified Deposits include predominantly coarsegrained glaciofluvial and glaciodeltaic sediments graded to small glacial lakes in the Sawmill River 

and Millers River valleys and their tributary valleys. In the Connecticut River valley, coarse- and 

fine-grained sediments of glacial Lake Hitchcock are present. Distribution of bedrock outcrops and 

shallow-bedrock areas is from Balk (1956b). Additional bedrock outcrops and shallow-bedrock 

areas are most likely present, particularly in areas of thin till that have steep slopes and irregular 

topography. Some postglacial were units mapped using 2005 orthophoto images. 

Goshen Quadrangle 

Map units were modified from Hatch and Warren (1982). Glacial Stratified Deposits include icemarginal glacial lake deposits in the Chapel Brook and West Branch Mill River valleys, which 

drained easterly toward the retreating ice lobe in the Connecticut valley, and remnants of sedimentdammed glacial lake deposits in the Westfield River valley. Bedrock outcrops include only those 

examined in the field during bedrock mapping (Hatch and Warren, 1982). The distribution of 

shallow-bedrock areas was interpreted by topographic analysis and the location of bedrock 

outcrops. Additional bedrock outcrops and shallow-bedrock areas are present, particularly in areas 

of thin till that have steep slopes and (or) irregular topography. Some postglacial units were 

mapped using 2005 orthophoto images. 

Williamsburg Quadrangle 

Map units were reproduced from Segerstrom (1955b). Glacial Stratified Deposits include icemarginal glacial lake deposits in the Roaring Brook and West Brook valleys, which drained 

easterly toward the retreating ice lobe in the Connecticut valley, and sediment-dammed glacial lake 

deposits in the Mill River valley, in the southwestern part of the quadrangle. Coarse- and finegrained deposits of glacial Lake Hitchcock occur in the eastern part of the quadrangle. Bedrock 

outcrops were mapped mainly in areas of glacial stratified deposits. The shallow-bedrock unit is 

slightly modified from the Qgm (thin ground moraine) unit of Segerstrom (1955b), which is 

defined as “thin deposits of ground moraine (till) with many exposures of bedrock;” this unit is 

more extensive than in other quadrangles and is probably overmapped. The thick-till unit is slightly 

modified from the Qgd (drumlins) unit of Segerstrom (1955b). Additional areas of thick till may be 

expected in places not mapped as shallow bedrock, particularly beneath smooth slopes on the 

northerly sides of bedrock hills. 

Mount Toby Quadrangle 

Map units were reproduced from Jahns (1951). Glacial Stratified Deposits include predominantly 

coarse- and fine-grained deposits of glacial Lake Hitchcock. Bedrock outcrops are mapped mainly 

in areas of glacial stratified deposits. The shallow-bedrock unit is slightly modified from the Qgm 

(thin ground moraine) unit of Jahns (1951), which is defined as “thin deposits of ground moraine 

(till) with many exposures of bedrock;” this unit is more extensive than in other quadrangles and is 

probably overmapped. The thick-till unit is slightly modified from the Qgd (drumlins) unit of Jahns 
18

(1951). Additional areas of thick till may be expected in places not mapped as shallow bedrock, 

particularly beneath smooth slopes on the northerly sides of bedrock hills. 

Shutesbury Quadrangle 

Map units were reproduced from Stone (1978). Glacial Stratified Deposits include deposits of icedammed glacial lakes in the west- and northwest-draining valleys of Amethyst Brook, Dean Brook, 

Roaring Brook, and the Sawmill River, and deposits of sediment-dammed lakes in the southdraining valleys of the West Branch Swift River and Doolittle Brook. Coarse- and fine-grained 

deposits of glacial Lake Hitchcock are present in the southwestern part of the quadrangle. The 

shallow-bedrock unit is defined as areas where bedrock is inferred to be less than 10 ft beneath the 

surface and where numerous bedrock outcrops are likely to be found. 

Westhampton Quadrangle 

Warren, C.R., 1976, unpublished field map. Glacial Stratified Deposits include coarse-grained, icedammed glacial lake deposits in the Sodom Brook and North Branch Manhan River valleys, which 

drained easterly toward the retreating ice margin. Remnants of coarse-grained sediment-dammed 

glacial lake deposits are present in the south-draining Westfield River valley. Distribution of 

bedrock outcrops is from Clark (1987). Shallow-bedrock areas were interpreted from topographic 

analysis and the distribution of bedrock outcrops. Additional bedrock outcrops and shallowbedrock areas are most likely present, particularly in areas of thin till that have steep slopes and (or) 

irregular topography. Some postglacial units were mapped using 2005 orthophoto images. 

Easthampton Quadrangle 

Larsen, F.D., 1976, unpublished field map. Glacial Stratified Deposits include coarse-grained, icedammed glacial lake deposits in the Meadow Brook, Turkey Brook, and North Branch Manhan 

River valleys, which drained easterly toward the retreating ice margin. Coarse- and fine-grained 

deposits of glacial Lake Manhan and glacial Lake Hitchcock are present in the lowland areas. 

Bedrock outcrops have not been mapped in this quadrangle; shallow-bedrock areas were delineated 

using topographic analysis. Additional shallow-bedrock areas are most likely present, particularly 

in areas of thin till that have steep slopes and (or) irregular topography. Some postglacial units were 

mapped using 2005 orthophoto images. 

Mount Holyoke Quadrangle 

Map units were modified from Balk (1957) using unpublished field maps from Larsen, F.D. (1976) 

and Stone, J.R. (1976). Glacial Stratified Deposits are predominantly coarse- and fine-grained 

deposits of glacial Lake Hitchcock. The shallow-bedrock unit is modified from the areas shown as 

bedrock units on the map of Balk (1957); these areas are likely to contain abundant bedrock 

outcrops. Thick-till areas were interpreted from topographic analysis. Some postglacial units were 

mapped using 2005 orthophoto images. 
19

Belchertown Quadrangle 

Map units were reproduced from Caggiano (1978). Glacial Stratified Deposits include coarsegrained deposits of sediment-dammed glacial lakes in the Jabish Brook and Broad Brook valleys 

and an ice-dammed glacial lake in the Knights Pond valley, and coarse- and fine-grained deposits 

of glacial Lake Hitchcock in the western part of the quadrangle. The shallow-bedrock unit is 

defined as areas where surficial material is less than 10 ft thick. Thick-till areas were mapped based 

on topographic analysis and on the position of drumlin axes shown on the map of Caggiano (1978). 

Some postglacial units were mapped using 2005 orthophoto images.

Woronoco Quadrangle 

Warren, C.R., 1976, unpublished field map. Glacial Stratified Deposits include coarse-grained, icedammed glacial lake deposits in upland areas, and coarse- and fine-grained deposits of glacial Lake 

Westfield in the lowlands. Distribution of bedrock outcrops is from Stanley and others (1982). 

Shallow-bedrock areas were interpreted from topographic analysis and from the distribution of 

bedrock outcrops. Additional bedrock outcrops and shallow-bedrock areas are most likely present, 

particularly in areas of thin till that have steep slopes and irregular topography. Some postglacial 

units were mapped using 2005 orthophoto images. 

Mount Tom Quadrangle 

Map units were reproduced from Larsen (1972). Glacial Stratified Deposits include coarse- and 

fine-grained deposits of glacial Lake Westfield in the western part of the quadrangle, glacial Lake 

Manhan in the northern part, and glacial Lake Hitchcock in the eastern part. The shallow-bedrock 

unit is defined as areas of abundant outcrops. Thick-till areas were mapped based on topographic 

analysis and on the position of drumlin axes shown on the map of Larsen (1972).

Springfield North Quadrangle 

Larsen, F.D., 1976, unpublished field map. Glacial Stratified Deposits include coarse- and finegrained deposits of glacial Lake Hitchcock. Bedrock outcrops and shallow-bedrock areas were 

interpreted from topographic analysis and orthophoto imagery. Some postglacial units were 

mapped using 2005 orthophoto images. 

Ludlow Quadrangle 

Map units were modified from Leo (1974) using unpublished field maps by Larsen, F.D. (1976). 

Glacial Stratified Deposits include coarse-grained, ice-dammed glacial lake deposits in upland 

tributary valleys of the Chicopee River, and coarse-grained deltaic deposits of glacial Lake 

Hitchcock in the western part of the quadrangle. The shallow-bedrock unit is defined as areas of 

abundant outcrops. Thick-till areas were mapped based on topographic analysis.
20

Southwick Quadrangle 

Map units were reproduced from Schnabel (1971). Glacial Stratified Deposits include ice-dammed 

glacial lake deposits in the Dickinson Brook and Munn Brook valleys, sediment-dammed glacial 

lake deposits in the vicinity of Congamond Lakes, and coarse-grained deposits of glacial Lake 

Westfield in the northeastern part of the quadrangle. The shallow-bedrock unit is defined as areas 

of abundant outcrops and patches of thin surficial material. Thick-till areas were mapped based on 

topographic analysis and on the position of drumlin axes shown on the map of Schnabel (1971).

West Springfield Quadrangle 

Map units were reproduced from Colton and Hartshorn (1970). Glacial Stratified Deposits in the 

eastern half of this quadrangle include coarse- and fine-grained deposits of glacial Lake Hitchcock; 

the western half of the quadrangle includes predominantly coarse-grained deposits of glacial Lake 

Westfield. The shallow-bedrock unit is defined as large areas of nearly continuous bedrock outcrop. 

Thick-till areas were mapped based on topographic analysis and on the position of drumlin axes 

shown on the map of Colton and Hartshorn (1970).

Springfield South Quadrangle 

Map units were reproduced from Hartshorn and Koteff (1967). Glacial Stratified Deposits are 

predominantly coarse- and fine-grained deposits of glacial Lake Hitchcock. The shallow-bedrock 

unit is defined as areas of scattered outcrops and areas of thinly veneered bedrock. Thick-till areas 

were mapped based on topographic analysis, on well and test-hole data, and on the position of 

drumlin axes shown on the map of Hartshorn and Koteff (1967).

Hampden Quadrangle 

Map units were reproduced from Hildreth and Colton (1982). Glacial Stratified Deposits include 

coarse-grained deposits of a lowering series of ice-dammed glacial lakes in the upper Scantic River 

valley and its tributaries, and coarse-grained deposits of sediment-dammed glacial lakes in the 

lower Scantic and Mill River valleys. Coarse-grained deltaic deposits of glacial Lake Hitchcock 

are present in the northwestern part of the quadrangle. The shallow-bedrock unit is defined as areas 

of closely spaced outcrops and areas where surficial materials are less than 10 ft thick. Thick-till 

areas were mapped based on topographic analysis, on well and test-hole data, and on the position of 

drumlin axes shown on the map of Hildreth and Colton (1982).