Prepared in cooperation with the Commonwealth of Massachusetts 

Massachusetts Geological Survey and Executive Office for Administration and Finance 

Surficial Geologic Map of the Norton-Manomet-WestportSconticut Neck 23-Quadrangle Area in Southeast Massachusetts 

Compiled by Byron D. Stone, Janet R. Stone, Mary L. DiGiacomo-Cohen, and Kevin A. Kincare 

Open-File Report 2006-1260-F 

U.S. Department of the Interior

U.S. Geological Survey 
U.S. Department of the Interior 

KEN SALAZAR, Secretary 

U.S. Geological Survey 

Marcia K. McNutt, Director 

U.S. Geological Survey, Reston, Virginia: 2011 

For product and ordering information:
 

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

Telephone: 1-888-ASK-USGS 

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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, B.D., Stone, J.R., DiGiacomo-Cohen, M.L., and Kincare, K. A., comps., 2011, Surficial geologic map of the 

Norton-Manomet-Westport-Sconticut Neck 23-quadrangle area in southeast Massachusetts: U.S. Geological Survey
 

Open-File Report 2006-1260-F, 21 sheets, scale 1:24,000, 22-p. text.
 

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: Kettle depressions, cranberry bogs, and sand and gravel operations in Plymouth, Massachusetts. The 

Billington Sea is a large compound kettle. Older, smaller cranberry bogs occupy natural kettle depressions. Newer, 

larger cranberry bogs occupy kettle depressions and excavated sand and gravel deposits.
 

ii 
Contents 

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

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

Glacial till deposits ..................................................................................................................................................... 3
 

Glacial moraine deposits ........................................................................................................................................... 3
 

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

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

Description of Map Units ............................................................................................................................................... 6
 

Map Compilation ...........................................................................................................................................................10 

References Cited ..........................................................................................................................................................13
 

Appendix: Sources of Data by 7.5-Minute Quadrangle .................................................................................................16
 

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............................................................................................................................................................. 5
 

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

4. Index map showing 7.5-minute, 1:24,000-scale quadrangles in this compilation .................................................... 11
 

5. Index map showing compilation areas in Massachusetts ........................................................................................ 12
 

iii 
 

 

 

 

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) 

iv 
Surficial Geologic Map of the Norton-ManometWestport-Sconticut Neck 23-Quadrangle Area in 

Southeast Massachusetts 

Compiled by Byron D. Stone, Janet R. Stone, Mary L. DiGiacomo-Cohen, and Kevin Kincare 

Introduction 

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

surface in an area of 23 7.5-minute quadrangles (919 mi2 total) in southeastern 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 

Department of Transportation, Highway Division) (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. The eastern part of this 23-quadrangle map differs from the rest of 

Massachusetts in that surficial moraine and stratified materials entirely cover the basal till and 

bedrock surfaces, which are shown on the basal layer of this map database. In addition, moraine 

deposits are more extensive and complex than in northern Massachusetts. 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 report covering 23 quadrangles revises previous 

1
 
digital surficial geologic maps (Stone and others, 1993; MassGIS, 1999) that were compiled on 

base maps at regional scales of 1:125,000 and 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). In the southeastern region, the 

glacial deposits are divided into two broad categories, glacial till and glacial moraine deposits and 

glacial stratified deposits. Glacial till, the most widespread glacial deposit in the subsurface, was 

laid down directly on bedrock and on local, older deposits by glacier ice. Glacial moraine deposits 

accumulated in ice-walled lakes and streams and on stagnant, buried ice in front of the receding 

edge of the ice sheet during the last deglaciation. Small moraine deposits accumulated in scattered 

patches along the ice margin. Glacial stratified deposits in the eastern part of the map area were laid 

down by glacial meltwater in streams and lakes adjacent to large moraines or stagnant ice at the 

2
 
 

front of the retreating ice margin. To the west, stratified deposits accumulated within local stagnant 

ice-bounded basins, and in streams and lakes that occupied valleys and lowland areas in front of the 

retreating ice margin. Postglacial sediments, primarily floodplain alluvium, swamp deposits, and 

beach and dune 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; it supports scattered gravel clasts and boulders. 

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 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 (thin-till unit on the map). The lower till ("old" till) 

was deposited during an earlier glaciation (probably Illinoian) and 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 in Massachusetts 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. 

Glacial moraine deposits are scattered throughout a large part of the map area and are 

defined on the map as either end moraine or thrust-moraine deposits. Only one glacial thrust 

deposit occurs in the area, and it covers an extensive area just east of the town of Buzzard Bay, in 

the southern part of the Sagamore quadrangle and the northern part of the Pocasset quadrangle. 

This thrust-moraine deposit includes shallow surface layers of sandy and bouldery ablation till and 

local compact sandy till, and thick subsurface deposits composed of sorted and layered, glacially 

deformed meltwater sediments, as reported in drill hole descriptions. These thrust-moraine deposits 

form the Sandwich moraine (Oldale and O’Hara, 1984). End moraine deposits are composed of a 

surface layer, 6 to 30 ft thick, of sandy and bouldery ablation till, local compact sandy till, or a 

layered, sandy and bouldery sediment of probable debris-flow origin. Sedimentary units in all of 

the large moraines have limited lateral extent and irregular thickness; stratification is deformed by 

collapse structures around kettle depressions and by glaciotectonic folds and thrust faults in some 

deposits. These deposits were laid down along active ice margins during retreat of the last (late 

Wisconsinan) ice sheet. Small moraines are present locally elsewhere in the western part of this 

map area, in the Boston area, and in the Gloucester-Rockport area (Gloucester quadrangle) 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 

3
 
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 older deltaic sediments or moraines 

(sediment-dammed lakes). Many of the coarse sediments in deltaic deposits and fine sediments in 

lake-bottom deposits shown in this map compilation are related to an extensive sediment-dammed 

lake, glacial Lake Narragansett, which expanded from the Narragansett Bay region of Rhode Island 

(Boothroyd, 2003; Boothroyd and August, 2008) into the coastal valleys of Block Island Sound, 

Buzzards Bay, and the Taunton River drainage basin in southeastern Massachusetts. 

Detailed geologic maps typically 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-ice-contact 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; the glaciodeltaic outwash plains in the eastern part of this map area are some of 

the most extensive morphosequences in Massachusetts. Most morphosequences are less than 1 

mile in length, as in the western part of this map area. In any one basin, individual 

morphosequences were deposited successively 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 of this report, coarse-grained and fine4
 
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). 

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, glacial stratified deposits are 100 to >500 ft 

thick, and, combined with moraine deposits, completely cover the subsurface till, coastal plain 

deposits, and bedrock. In the southeastern lowland of Massachusetts shown on this map, and in 

parts of the Connecticut River valley, extensive stratified deposits also cover the bedrock surface. 

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

underlies the floodplains of most streams and rivers. Swamp and marsh deposits 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. Deposits influenced by man, such as construction sites and cranberry 

bogs, also are shown. 

5
 
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 

Cranberry bog—Some natural freshwater swamps or peat bogs overlain locally by 

artificially emplaced sand or other fill; in many places in southeastern 

Massachusetts, cranberry bogs are created by excavation into sand and gravel 

deposits that form the bed; peat and other organic material have been artificially 

emplaced over the bed and water drainage pathways are diverted into the area to 

control seasonal flooding of the bog 

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 in the map 

area are along the Taunton, Threemile, Runnins, Palmer, and Acushnet Rivers. 

Alluvium overlies thicker stratified deposits; thin alluvial deposits probably lie 

beneath salt-marsh deposits in coastal valley reaches that were flooded during the 

postglacial rise of sea level 

Swamp and marsh deposits—Organic muck and peat that contain minor amounts 

of sand, silt, and clay, stratified and poorly sorted, in freshwater swamps and 

marshes, kettle depressions, or poorly drained areas. Swamp and marsh deposits are 

shown only where they are estimated to be at least 3 ft thick; most deposits are less 

than 10 ft thick. Swamp and marsh deposits overlie glacial meltwater deposits and 

postglacial pond deposits in kettle depressions. They locally overlie glacial till in 

stream channels that have been eroded through thin glacial meltwater deposits 

Salt-marsh deposits—Peat and organic muck interbedded with sand and silt, 

deposited in saltwater or brackish-water environments of low wave energy along the 

coast and in river estuaries. Salt-marsh deposits are generally a few feet to 25 ft 

thick. In the major estuaries, these deposits locally overlie estuarine deposits (not 

mapped), which are sand and silt with minor organic material as much as 30 to 80 ft 

thick. The salt-marsh and estuarine deposits generally are underlain by adjacent 

glacial stratified deposits 

6
 
 

Beach and dune deposits—Sand and fine gravel deposited along the shoreline by 

waves and currents and by wind action. The texture of beach deposits varies over 

short distances and is generally controlled by the texture of nearby glacial materials 

exposed to wave action. Sand beach deposits are composed of moderately sorted, 

very coarse to fine sand, commonly laminated. Coarser layers locally contain some 

fine gravel particles; finer layers contain some very fine sand and silt. Gravel beach 

deposits are composed of granule- to cobble-size clasts in moderately sorted thin 

beds; deposits contain minor amounts of sand within gravel beds and thin beds of 

sand as alternating layers. Beach deposits are rarely more than a few feet thick. 

Dune deposits are composed of moderately to well-sorted, fine to medium sand, 

variably massive, laminated, and crossbedded. Dune deposits are as much as 50 ft 

thick. Unit includes artificial sand deposits in locally replenished beaches 

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. Stagnantice deposits are surface coarse sediments bounded by ice-contact slopes, present on tops of till hills 

or extending >30 ft above the altitudes of adjacent meltwater morphosequences in lowlands. These 

stagnant-ice deposits are aligned in belts parallel to the retreating ice margin. 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 map. 

PARTICLE DIAMETER 

10 2.5 .16 

256 64 4 

.08 

2 

.04 .02 .01 

1 .5 .25 

.005 .0025 .00015 inches 

.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). 

7
 
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 Narragansett, fine deposits are overlain by as much as 30 ft of fine to 

medium sand, deposited as the lake became shallower; this sand has not been 

mapped separately 

Stagnant-ice deposits—Surface coarse sediments include scattered large surface 

boulders, gravel deposits and sand and gravel deposits, totaling 5 to 30 ft thick, that 

overlie chiefly sand deposits. Sand deposits contain deltaic foreset bedding and 

interlayered beds of fine sand, silt, and little clay. Sand and silty sand deposits 

extend downward to basal till and bedrock. Flowtill sediments are interlayered under 

ice-contact slopes. Stratification in surface and underlying sediments is generally 

distorted and faulted due to postdepositional collapse related to melting of buried 

ice. Stagnant-ice deposits are confined to irregular hummocky hills, bounded by icecontact slopes, present on tops of till hills or extending >30 ft above the altitudes of 

adjacent meltwater morphosequences in lowlands. Deposits are aligned in belts 

parallel to the retreating ice margin 

Glacial Till and Moraine Deposits 

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

containing scattered gravel clasts and few large boulders; predominantly upper till of 

the last glaciation; loose to moderately compact, generally sandy, commonly stony. 

Till is mapped where it is generally less than 10 to 15 ft thick including areas of 

shallow bedrock. Two facies are present in some places: a looser, coarser grained 

ablation facies, melted out from supraglacial position; and an underlying more 

compact, finer grained lodgement facies deposited subglacially. Both ablation and 

lodgement facies of upper till are sandy and stony and are derived from coarsegrained crystalline rocks. Subsurface till overlies fresh, nonweathered bedrock; this 

basal till varies in known thickness from <5 to >50 ft (Williams and Willey, 1973; 

8
 
Williams and Tasker, 1974; Hansen and Lapham, 1992; Masterson and others, 

1997). Till may overlie older Pleistocene deposits locally 

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 

Till overlying sand deposits—In the Pine Hills area, Manomet quadrangle, surface 

deposits of till and overlying thin colluvium, both consisting of a nonsorted, 

nonstratified matrix of sand, some silt, and little clay containing scattered gravel 

clasts and few large boulders; loose to moderately compact, generally sandy, 

commonly stony. The surface nonsorted deposits, 6 to 30 ft thick, overlie sand, 

gravel, and silty sand deposits that extend >250 ft downward to basal till and 

bedrock (Hansen and Lapham, 1992). These subsurface stratified deposits crop out 

in the sides of Pine Hills and Indian Hill, where they appear to be coarse-grained 

glacial meltwater sediments 

End moraine deposits—Composed predominantly of boulders and ablation facies 

sandy upper till; lenses of stratified sand and gravel occur locally within the till. 

Surface boulders on end moraine deposits are generally more numerous than on 

adjacent till surfaces; dense concentrations of boulders are present in some places. 

Deposits occur as free-standing hummocky landforms, commonly in ridges that 

trend ENE – WSW, and range in thickness from 10 to 60 ft 

Thrust-moraine deposits—Surface deposits of nonsorted, nonstratified matrix of 

sand, some silt, and little clay containing scattered gravel clasts and large boulders; 

predominantly till of the last glaciation; loose to moderately compact, generally 

sandy, commonly stony. Two facies of till are present in some places: a looser, 

coarser grained ablation facies, melted out from supraglacial position; and an 

underlying more compact, finer grained lodgement facies deposited subglacially 

(Oldale, 1975). Both ablation and lodgement facies of till are stony, containing 

boulders, and are derived from coarse-grained crystalline rocks. The surface 

nonsorted deposits, 6 to 30 ft thick, overlie sand, gravel, and silty sand sediments 

that compose the large meltwater deposit extending to the south and downward to 

basal till and bedrock. Surface deposits and stratification in underlying sediments 

commonly are distorted and faulted due to readvance of the ice margin (Oldale and 

O’Hara, 1984) postdepositional collapse related to melting of buried ice 

9
 
 

Bedrock Areas 

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

color shows extent of individual bedrock outcrops; line 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 detail of bedrock outcrop mapping in each quadrangle 

Map Compilation 

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

in an area of 23 7.5-minute quadrangles in southeastern Massachusetts. The quadrangles are 

Norton, Taunton, Bridgewater, Plympton, Plymouth, Manomet, East Providence, Somerset, 

Assonet, Assawompset Pond, Snipatuit Pond, Wareham, Sagamore, Bristol, Fall River, Fall River 

East, New Bedford North, Marion, Onset, Tiverton, Westport, New Bedford South, and Sconticut 

Neck (fig. 4; fig. 5, area F). Also included in this report is the northern end of the Pocasset 

quadrangle; the portion lying north and west of the Cape Cod Canal was not published as part of 

Open-File Report 2006-1260-E. 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 preceded that of area F). 

The surficial geologic map was compiled in several steps: 

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

and georeferenced by MassGIS; 

2) The Office of the Massachusetts State Geologist (now the Massachusetts Geological 

Survey) 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 three shapefile 

layers: Postglacial deposits including artificial fill, swamp and marsh deposits, cranberry 

bogs, beach and dune deposits, and alluvium; glacial stratified deposits including coarsegrained, stagnant-ice, and fine-grained deposits; and glacial till, moraine deposits, and 

bedrock including deposits of thin till, thick till (drumlins), end moraine, thrust moraine, 

till overlying sand, and 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 19 

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

5) The 23 individual quadrangle maps were joined and edge-matched in order to form a 

seamless digital geologic map. 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 23 USGS 7.5-minute, 1:24,000-scale quadrangles in this compilation. Sheet numbers refer to 

the 21 Adobe PDF map files of individual quadrangles. The Massachusetts part of the Bristol quadrangle 

is shown with the East Providence quadrangle on sheet 7, and the Tiverton quadrangle is shown with the 

Westport quadrangle on sheet 19. The northern portion of the Pocasset quadrangle is shown with the 

Sagamore quadrangle on sheet 13; the remainder of the Pocasset quadrangle was mapped and included 

in Open-File Report 2006-1260-E. 

All geologic mapping was completed at 1:24,000 scale. The 1:24,000-scale, 10-ft contour 

interval topographic base maps (1955–1972 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 

11
 
report contains three 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 boundaries. Unlike the units in conventional geologic maps, the digitally 

defined map units are arranged in layers according to superposition. The shapefile for till, moraine 

deposits, 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 

deposits, such as swamp deposits and floodplain alluvium, and also beneath water bodies. The 

shapefile for postglacial deposits is the top layer because these materials overlie the older materials 

in the other two 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 1–21, 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 

Boothroyd, J.C, 2003, Quaternary geologic mapping in an urban environment [abs.]: Geological 

Society of America Abstracts with Programs, v. 38, p. 78. 

Boothroyd, J.C., and August, P.V., 2008, Geological and contemporary landscapes of the 

Narragansett Bay ecosystem, in Desbonnet, A., and Costa-Pierce, B.A., eds., Science for 

ecosystem-based management; Narragansett Bay in the 21st century, New York, N.Y., Springer, 

p. 1–33. 

Hansen, B.P., and Lapham, W.W., 1992, Geohydrology and simulated ground-water flow, 

Plymouth-Carver Aquifer, southeastern Massachusetts: U.S. Geological Survey Water-Resources 

Investigations Report 90−4204, 91 p. 

Hartshorn, J.H., 1960, Geology of the Bridgewater quadrangle, Massachusetts: U.S. Geological 

Survey Geologic Quadrangle Map GQ−127, scale 1:24,000. 

Hartshorn, J.H., 1967, Geology of the Taunton quadrangle, Bristol and Plymouth Counties, 

Massachusetts: U.S. Geological Survey Bulletin 1163−D, 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., 1953, Surficial geology of the Ayer quadrangle, Massachusetts: U.S. Geological 

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

Koteff, Carl, 1964, Geologic map of the Assawompset Pond quadrangle, Massachusetts: U.S. 

Geological Survey Geologic Quadrangle Map GQ–265, 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. 

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. 

Larson, G.J., 1982, Nonsynchronous retreat of ice lobes from southeastern Massachusetts, in 

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

Dubuque, Iowa, Kendall/Hunt, p. 101−114. 

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

Iowa, Kendall/Hunt, 252 p. 

Lyons, P.C., 1977, Report on the bedrock geology of the Narragansett Basin, Massachusetts and 

Rhode Island, U.S. Geological Survey Open-File Report 77−816, scale 1:31,250. 

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 [abs.]: 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. 

Masterson, J.D., Stone, B.D., Walter, D.R., and Savoie, J., 1997, Water resources of western Cape 

Cod: U.S. Geological Survey Hydrologic Atlas HA−741, map scale 1:48,000. 

13
 
Mather, K.F., Goldthwait, R.P., and Theismeyer, L.R., 1942, Pleistocene geology of western Cape 

Cod, Massachusetts: Geological Society of America Bulletin v. 53, p. 1127−1174. 

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., 1975, Geologic map of the Sandwich quadrangle, Barnstable County, Cape Cod, 

Massachusetts: U.S. Geological Survey Geologic Quadrangle Map GQ−1222, scale 1:24,000. 

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., and O’Hara, C.J., 1984, Glaciotectonic origin of the Massachusetts coastal end 

moraines and a fluctuating late Wisconsinan ice margin: Geological Society of America Bulletin, 

v. 95, p. 61−74. 

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. 

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. 

Smith, J.H., 1955, Surficial geology of the Bristol quadrangle and vicinity, Rhode Island and 

Massachusetts: U.S. Geological Survey Geologic Quadrangle Map GQ−70, scale 1:31,680. 

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, B.D., and Peper, J.D., 1982, Topographic control of the deglaciation of eastern 

Massachusetts: Ice lobation and the marine incursion, in Larson, G.J., and Stone, B.D., eds., Late 

Wisconsinan glaciation of New England: Dubuque, Iowa, Kendall/Hunt, p. 145−166. 

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 

14
 
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, 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. 

Willey, R.E., Williams, J.R., and Tasker, G.D., 1978, Water resources of the coastal drainage 

basins of southeastern Massachusetts, Westport River, Westport to Seekonk; U.S. Geological 

Survey Hydrologic Atlas HA−275, 5 maps. 

Williams, J.R., and Willey, R.E., 1973, Bedrock topography and texture of unconsolidated deposits, 

Taunton River basin, southeastern Massachusetts; U.S. Geological Survey Miscellaneous 

Geologic Investigations Map I−742, scale 1:48,000. 

Williams, J.R., and Tasker, G.D., 1974, Water resources of the coastal drainage basins of 

southeastern Massachusetts, Plymouth to Weweantic River, Wareham: U.S. Geological Survey 

Hydrologic Atlas HA−507, 2 maps. 

Williams, J.R., and Tasker, G.D., 1978, Water resources of the coastal drainage basins of 

southeastern Massachusetts, northwest shore of Buzzards Bay: U.S. Geological Survey 

Hydrologic Atlas HA–560, 5 maps. 

15
 
Appendix 

Sources of Data by 7.5-Minute Quadrangle 

Norton Quadrangle 

Stone, B.D., and Peper, J.D. (1982, unpublished field compilation map). Glacial stratified deposits 

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

glacial lakes in the Threemile River and Wading River valleys, Palmer River, Segreganset River, 

Canoe River, Rumford River valleys, and sediments graded to glacial Lake Narragansett in the 

middle Threemile River and Mulberry Meadow Brook valleys. Thick-till areas were delineated 

based on topographic analysis and subsurface data of Williams and Willey (1973). Distribution of 

bedrock outcrops is from Williams and Willey (1973), Lyons (1977), Willey and others (1978), and 

Stone and Peper in 1982 (unpublished). The shallow-bedrock unit represents areas of small 

scattered bedrock outcrops. Additional bedrock outcrops and shallow-bedrock areas are most likely 

present, particularly in areas of thin till with steep slopes and irregular topography. Some 

postglacial units were mapped using 2005 orthophoto images. 

Taunton Quadrangle 

Map units were modified from Hartshorn (1967). Glacial stratified deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments mapped as a group of glaciofluvial 

landforms (units Qic, Qk, Qkt, Qkp, Qow, Qgf) included in glaciofluvial deposits and kame delta 

(unit Qkd, in glaciolacustrine deposits) of Hartshorn (1967). These deposits were graded to glacial 

Lake Narragansett in the Taunton River lowland. Stagnant-ice deposits include coarse-grained 

glaciofluvial and glaciodeltaic sediments, flowtill deposits and boulders, mapped as kame deposits 

(unit Qk) of Hartshorn (1967). The thick-till unit is from the Qd (drumlin) unit of Hartshorn (1967). 

Additional areas of thick till may be expected beneath smooth slopes on the northerly sides of 

bedrock hills. Distribution of bedrock outcrops is from Hartshorn (1967) and Williams and Willey 

(1973). The shallow-bedrock unit represents areas of numerous exposures. Some postglacial units 

were mapped using 2005 orthophoto images. 

Bridgewater Quadrangle 

Map units were modified from Hartshorn (1960). Glacial stratified deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments mapped as a group of glaciofluvial 

landforms (units Qic, Qk, Qkt, Qkp, Qow, Qgf) included in glaciofluvial deposits and kame delta 

(unit Qkd) glaciolacustrine deposits of Hartshorn (1960). These deposits were graded to glacial 

Lake Narragansett in the Taunton River lowland and to local glacial lakes in the Nemasket River 

lowland in the southeastern part of the map area. Stagnant-ice deposits include coarse-grained 

glaciofluvial and glaciodeltaic sediments, flowtill deposits and boulders, mapped as kame deposits 

(unit Qk) of Hartshorn (1960). Additional areas of thick till may be expected beneath smooth slopes 

on the northerly sides of bedrock hills. Distribution of bedrock outcrops is from Hartshorn (1960). 

16
 
The shallow-bedrock unit represents areas of numerous exposures. Some postglacial units were 

mapped using 2005 orthophoto images. 

Plympton Quadrangle 

Goldthwait, R.P., and Thiesmeyer, L.R. (1940, unpublished field map); and Stone B.D., and 

Kincare, K.A. (2010, unpublished field compilation map). Glacial stratified deposits include 

predominantly coarse-grained glaciofluvial and glaciodeltaic sediments mapped as part of the 

Carver outwash plain (Mather and others, 1942; Larson, 1982) in the southeastern part of the area, 

as kames and kame deltas in the northeastern part of the area, and as kames and kame deltas that 

were graded to glacial Lake Narragansett in the Taunton River lowland (Larson, 1982; Stone and 

Peper, 1982). Other parts of these deposits were graded to local glacial lakes in the Shorts Brook 

and upper Winnetuxet River lowlands in the southwestern and central parts of the map area. The 

thick-till area was delineated based on its topographic expression. Distribution of bedrock outcrops 

is from Williams and Willey (1973) and Lyons (1977). Some postglacial units were mapped using 

2005 orthophoto images. 

Plymouth Quadrangle 

Thiesmeyer, L.R. (1940, unpublished field map); and Stone and Kincare (2010, unpublished field 

map). Glacial stratified deposits include predominantly coarse-grained glaciofluvial and 

glaciodeltaic sediments mapped as part of the Wareham, King’s Pond, and Carver outwash plains 

and the collapsed sand and gravel sediments of the Ellisville and Hog Rock moraines (Mather and 

others, 1942; Larson, 1982) in the southwestern part of the area, as deposits of the Plymouth kame 

field in the northeastern part of the area, and as kames and kame deltas graded to glacial Lake 

Narragansett in the Jones River lowland (Lake Taunton of Larson, 1982; Stone and Peper, 1982). 

Small moraine deposits composed of till overlying gravel and sand are modified from deposits of 

the Monk’s Hill moraine of Thiesmeyer (1940, unpublished). Distribution of bedrock outcrops is 

from L.R. Thiesmeyer (1940, unpublished) and Stone and Kincare (2010, unpublished). The 

shallow-bedrock unit represents areas of small scattered bedrock outcrops. Some postglacial units 

and bedrock outcrops were mapped using 2005 orthophoto images. 

Manomet Quadrangle 

Goldthwait, R.P., and Thiesmeyer, L.R (1940, unpublished field map); and Stone B.D., and 

Kincare, K.A. (2010, unpublished field map). Glacial stratified deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments, mapped as part of the Wareham outwash 

plain. These deposits also include the collapsed sand and gravel sediments of the Ellisville moraine 

(Mather and others, 1942; Larson, 1982) in the southwestern part of the area, deposits of the 

Plymouth kame field in the northwestern part of the area, and kames and kame deltas graded to 

Lake Cape Cod Bay (Larson, 1982; Stone and Peper, 1982) in the eastern part of the area. The till 

overlying sand deposits beneath Pine Hills, Indian Hill, and Telegraph Hill are known from 

geophysical studies and drill-hole samples (Hansen and Lapham, 1992) and exposures in the sides 

of the hills. Some postglacial units mapped using 2005 orthophoto images. 

17
 
East Providence Quadrangle 

Stone, B.D. (1982, unpublished field map). Glacial stratified deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments graded to glacial Lake Narragansett in the 

Runnins River, Ten Mile River, and Palmer River lowlands. Thick-till areas were delineated based 

on topographic analysis. Distribution of bedrock outcrops is from Willey and others (1978), Lyons 

(1977), and Stone (1982). The shallow bedrock unit represents areas of numerous outcrops. 

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

thin till that have steep slopes and irregular topography. Some postglacial units were mapped using 

2005 orthophoto images. 

Somerset Quadrangle 

Peper, J.D., and Stone, B.D. (1982, unpublished field map). Glacial stratified deposits include 

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

Narragansett in the Palmer River, Cole River, and Taunton River valleys, and small glacial lakes in 

the upper Rocky Run, upper Cole River, and Segregansett River basins. Thick-till areas were 

delineated based on topographic analysis. Distribution of bedrock outcrops is from Willey and 

others (1978), Williams and Willey (1973), Lyons (1977), and Peper and Stone (1982, 

unpublished). The shallow bedrock unit represents areas of numerous outcrops. Some postglacial 

units were mapped using 2005 orthophoto images. 

Assonet Quadrangle 

Stone, B.D. (1982, unpublished field map). Glacial stratified deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments graded to glacial Lake Narragansett in the 

Taunton River and Assonet River valleys. Distribution of bedrock outcrops is from Williams and 

Willey (1973), Lyons (1977), and Stone (1982, unpublished). 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. 

Assawompset Pond Quadrangle 

Map units were reproduced from Koteff (1964). Glacial stratified deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments grouped in meltwater sequence deposits 

(units Qc1, Qc2, Qc5-Qc7, Qce3-4, Qcw3-4) and noncorrelated deposits (units Qc, Qsg) included in 

water-laid ice contact deposits of Koteff (1964). These deposits were graded to local glacial lakes 

in the Fall Brook and Squam Brook valleys, the Nemasket River lowland, and to glacial Lake 

Narragansett in the Taunton River lowland in the northwest corner of the map area. Stagnant-ice 

deposits include coarse-grained glaciofluvial and glaciodeltaic sediments, flowtill deposits and 

boulders, mapped as kame deposits (unit Qc) by Koteff (1964). Small moraine deposits composed 

of coarse gravel and sand are unit Qem2 of Koteff (1964). Thick-till areas were delineated based on 

topographic analysis and subsurface data of Williams and Willey (1973). Additional areas of thick 

till may be expected beneath smooth slopes on the northerly sides of bedrock hills. Distribution of 

bedrock outcrops is from Koteff (1964). The shallow-bedrock unit is slightly modified from the 

18
 
ruled pattern area of bedrock exposures of Koteff (1964), which is defined as “areas of abundant 

exposures and thin surficial deposits”. Some postglacial units were mapped using 2005 orthophoto 

images. 

Snipatuit Pond Quadrangle 

Thiesmeyer, L.R , and Goldthwait, R.P. (1940, unpublished field map); and Stone B.D., and 

Kincare, K.A., assisted by A. Lusk (2010, unpublished field map). Glacial stratified deposits 

include predominantly coarse-grained glaciofluvial and glaciodeltaic sediments that were graded to 

small glacial lakes in the Weweantic River and Sippican River valleys, and to glacial Lake 

Narragansett in the Taunton River lowland. Distribution of bedrock outcrops is from Williams and 

Willey (1973) and Lyons (1977). Additional areas of thick till may be expected, particularly 

beneath smooth slopes on the northerly sides of bedrock hills. Some postglacial units were mapped 

using 2005 orthophoto images. 

Wareham Quadrangle 

Goldthwait, R.P., and Thiesmeyer, L.R. (1940, unpublished field maps); Stone, B.D., and Kincare, 

K.A. (2010, unpublished field maps). Glacial stratified deposits include predominantly coarsegrained glaciofluvial and glaciodeltaic sediments mapped as part of the Wareham and King’s Pond 

outwash plains and the collapsed sand and gravel sediments of the Hog Rock moraine (Mather and 

others 1942; Larson, 1982). Stagnant-ice deposits include coarse-grained glaciofluvial and 

glaciodeltaic sediments, flowtill deposits and boulders (Mather and others, 1942; Larson, 1982). 

Thick-till areas were delineated based on topographic analysis and subsurface data of Williams and 

Tasker (1974). Additional areas of thick till may be expected beneath smooth slopes on the 

northerly sides of bedrock hills. Some postglacial units were mapped using 2005 orthophoto 

images. 

Sagamore Quadrangle 

Map units were modified from Thiesmeyer (1940, unpublished field map) and Stone and Kincare 

(2010, unpublished field map). Glacial stratified deposits include predominantly coarse-grained 

glaciofluvial and glaciodeltaic sediments mapped as part of the Wareham outwash plain and the 

collapsed sand and gravel sediments of the Hog Rock moraine (Mather and others, 1942; Larson, 

1982). Other parts of these deposits were graded to local glacial lakes in the southeastern and 

northeastern parts of the map area. Stagnant-ice deposits include coarse-grained glaciofluvial and 

glaciodeltaic sediments, flowtill deposits, and boulders. Moraine deposits are part of the Sandwich 

moraine of Thiesmeyer (1940, unpublished) in the southern part of the map area. Thick-till areas 

were delineated based on topographic analysis and subsurface data of Williams and Tasker (1974). 

Some postglacial units were mapped using 2005 orthophoto images. 

Bristol Quadrangle 

Map units were reproduced from Smith (1955). Glacial stratified deposits include predominantly 

coarse-grained glaciofluvial and glaciodeltaic sediments of outwash plain deposits (unit Qop) of 

Smith (1955), which grade to glacial Lake Narragansett deposits in the eastern Narragansett Bay 

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

19
 
Fall River Quadrangle 

Peper, J.D., assisted by D.A. Powars and M. Baginski (1982, unpublished field map). Distribution 

of bedrock outcrops is from Lyons (1977), Willey and others (1978), and Peper (1982, 

unpublished). 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. Additional bedrock outcrops and shallow-bedrock areas are 

most likely present, particularly in areas of thin till with steep slopes and irregular topography 

Some postglacial units were mapped using 2005 orthophoto images. 

Fall River East Quadrangle 

Peper, J.D., assisted by D.A. Powars and M. Baginski (1982, unpublished field map). Distribution 

of bedrock outcrops is from Williams and Willey (1973), Lyons (1977), Willey and others (1978), 

and Peper (1982, unpublished). 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. Additional bedrock outcrops and shallowbedrock areas are most likely present, particularly in areas of thin till with steep slopes and 

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

New Bedford North Quadrangle 

Peper, J.D., assisted by D.A. Powars and J.C. Haley (1982, unpublished field map). Glacial 

stratified deposits include predominantly coarse-grained glaciofluvial and glaciodeltaic sediments 

graded to glacial Lake Narragansett in the lower Acushnet River valley and small glacial lakes in 

the Paskamanset River and upland Acushnet Cedar Swamp valleys. Thick-till areas were delineated 

based on topographic analysis and subsurface data of Williams and Tasker (1978). Distribution of 

bedrock outcrops is from Williams and Tasker (1978) and Peper (1982, unpublished). The shallowbedrock unit represents areas of small scattered bedrock outcrops. Additional bedrock outcrops and 

shallow-bedrock areas are most likely present, particularly in areas of thin till with steep slopes and 

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

Marion Quadrangle 

Thiesmeyer, L.R , and Goldthwait, R.P. (1940, unpublished field map); Peper, J.D., and Stone, 

B.D. (1982, unpublished field map). Glacial stratified deposits include predominantly coarsegrained glaciofluvial and glaciodeltaic sediments graded to glacial Lake Narragansett in the 

Nasketucket River, Mattapoisett River, and coastal valley. Thick-till areas were delineated based on 

topographic analysis and subsurface data of Williams and Tasker (1978). Distribution of bedrock 

outcrops is from Williams and Tasker (1978) and Peper and Stone (1982, unpublished). Some 

postglacial units were mapped using 2005 orthophoto images. 

20
 
Onset Quadrangle 

Thiesmeyer, L.R , and Goldthwait, R.P. (1940, unpublished field map); Peper, J.D., and Stone, 

B.D. (1982, unpublished field map). Glacial stratified deposits include predominantly coarsegrained glaciofluvial and glaciodeltaic sediments graded to glacial Lake Narragansett in the coastal 

valley; these deposits were mapped as part of the Wareham outwash plain and the collapsed sand 

and gravel sediments of the Hog Rock moraine (Mather and others, 1942; Larson, 1982). Other 

parts of these deposits were graded to local glacial lakes in the southeastern and northeastern parts 

of the map area. Stagnant-ice deposits include coarse-grained glaciofluvial and glaciodeltaic 

sediments, flowtill deposits, and boulders. Moraine deposits are part of the Sandwich moraine 

(Theismeyer, 1940, unpublished) in the southern part of the map area. Thick-till areas were 

delineated based on topographic analysis and subsurface data of Williams and Tasker (1974). Some 

postglacial units were mapped using 2005 orthophoto images. 

Tiverton Quadrangle 

Map units were modified from Stone (1982, unpublished field map). Glacial stratified deposits 

include predominantly coarse-grained glaciofluvial and glaciodeltaic sediments graded to a local 

glacial lake in the Stony Brook (Sawdy Pond) valley. Distribution of bedrock outcrops is from 

Willey and others (1978) and Stone (1982, unpublished). The shallow-bedrock unit represents areas 

of small scattered bedrock outcrops. Areas of thick till may be expected beneath smooth slopes on 

the northerly sides of bedrock hills. 

Westport Quadrangle 

Peper, J.D., and Stone, B.D., assisted by D.A. Powars and M. Baginski (1982, unpublished field 

map); Willey and others (1978). 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. Additional bedrock outcrops and shallowbedrock areas are most likely present, particularly in areas of thin till with steep slopes and 

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

New Bedford South Quadrangle 

Peper, J.D., and Stone, B.D., assisted by D.A. Powars and J.C. Haley (1982, unpublished field 

map). Glacial stratified deposits include predominantly coarse-grained glaciofluvial and 

glaciodeltaic sediments graded to glacial Lake Narragansett in the Slocums River and Little River 

valleys and small glacial lakes in the Paskamanset River valley. Thick-till areas were delineated 

based on topographic analysis and subsurface data of Williams and Tasker (1978). Distribution of 

bedrock outcrops is from Williams and Tasker (1978) and Peper and Stone (1982 unpublished). 

The shallow-bedrock unit represents areas of small scattered bedrock outcrops. 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. 

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

areas of thin till with steep slopes and irregular topography. Some postglacial units were mapped 

using 2005 orthophoto images. 

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Sconticut Neck Quadrangle 

Peper J.D., assisted by J. Buchanan (1982, unpublished field map). Distribution of bedrock 

outcrops is from Williams and Tasker (1978) and Peper (1982, unpublished). Thick-till areas were 

delineated based on topographic analysis. Some postglacial units were mapped using 2005 

orthophoto images. 

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