100

300

100

250

150

250

300

150

0

0

300

250

100

250

250

200

200

200

50

150

50

200

200

200

200

0

100

200

150

50

50

0

200

0

0

100

250

150

200

50

25

100

50

200

50

50

25

50

150

0

100

50

50

50

150

100

50

100

200

200

150

0

50

100

0

0

25

100

0

-50

-50

-50

150

-50

-50

-50

50

25

-25

0

0

100

50

25

150

150

-50

-100

-100

150

0

100

50

100

100

0

0

200

-125

-100

-100

-125

250

25

200

150

100

50

50

25

25

0

0

0

-50

-25

100

150

50

50

-75

-75

-100

-100

-25

150

25

50

100

0

50

100

200

0

50

sw

sw

sw

af

af

af

sg

sg

sg

sg

sg

sg

sg

sg

f

sg

s

sg

s

sg

s

tt

tt

t

sg

tt

tt

tt

sg

s

f

sg

s

f

sg

s

f

s

f

s

f

em

em

em

sb

t

t

t

t

t

t

t

sg

sw

sw

sw

sw

sw

af

af

af

af af

af

af

af

af

af

t

t

t

al

al

al

sg

s

sg

s

sg

s

sg

s

sg

s

em

em

s

f

sg

sg

s

f

sg

f

f

f

sb

tt

t

s

f

s

f

tt

tt

sg

s

f

sg

sw

sg

s

al

al

s

s

s

s

s

s

sg

sg

s

A

A'

B

B'

C

C'

!

!

!

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KWD-1

KWD-2

KWD-3

URI-4

URI-3

URI-2

873

888

1065

1081

1086

1072

1123

1146

1155

1158

138

879

896

6

872

874

1076

1097

1231

1126

1133

1128

!

DESCRIPTION OF MAP UNITS

sg

s

f

sg

s

f

sg

Bedrock areas

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

color shows extent of individual bedrock outcrops; ruled patterns indicate areas where

small outcrops are too numerous to map individually 

Bedrock contour— Contours drawn on the surface of the bedrock; number is altitude 

in feet, interval is variable

Map units outside of study area 

Undifferentiated stratified deposits

Charlestown, Point Judith, and Congdon Hill end-moraine deposits 

MAP SYMBOLS

Contact between map units

Geologic study boundary

Model boundary 

Line of geologic section

Location of production wells and identification number

Location of wells shown on cross sections and identification number

Particle diameter

10 2.5 0.16 0.08 0.04 0.2 0.01 0.005 0.0025 0.00015 inches

256 64 4 2 1 0.5 0.25 0.125 0.063 0.004 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

150

872

URI-2 

A A'

EXPLANATION

Grain size particle diameters—Grain-size classification used in this report: modified from Wentworth (1922)

Quadrangle boundary 

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

emplaced, primarily in highway and railroad embankments, and in dams

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

to poorly sorted. Textures vary over short distances, both laterally and vertically, and are 

generally similar to the texture of adjacent glacial 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

Postglacial deposits—Alluvium is present beneath the floodplain surfaces of the Chipuxet River, although 

some surfaces are also underlain by swamp deposits; swamp deposits also occur in positions isolated from 

the floodplain, such as in kettle holes. Swamp deposits and alluvium are generally thin less than 10 feet (ft) 

thick and are underlain by thicker glacial deposits

Glacial meltwater deposits (stratified deposits)—Sorted and stratified sediments composed of gravel, 

sand, silt, and clay (as defined in chart below) deposited in layers by glacial meltwater. These sediments 

are classified into three textural units—sand and gravel deposits, sand deposits, and fine deposits. The 

texture of glacial stratified deposits is described throughout their whole vertical extent either as a single 

textural unit or as two or more units in various orders of superposition referred to as “stacked units.”

Contacts between subsurface textural units are not mapped with as great an accuracy or detail as those at 

the surface. All units of glacial stratified deposits overlie glacial till and (or) bedrock which is not included 

in the stacked unit.

Sand and gravel deposits—Composed of mixtures of sand and gravel particles within 

individual layers and as alternating layers. 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. 

Origin: Proximal deltaic and fluvial deposits and delta topset beds

Sand deposits—Composed mainly of very coarse to fine sand; 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. Layers are commonly well sorted. Origin: 

Deltaic foreset beds, distal lacustrine fan deposits, and distal fluvial deposits

Fine deposits—Composed of 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. Origin: Lake-bottom deposits, distal lacustrine fan deposits

Sand and gravel overlying sand—Sand and gravel less than 20 feet thick, horizontally 

bedded and overlies thicker, inclined layers of sand. Origin: Deltaic deposits

Sand overlying sand and gravel—Sand is of variable thickness overlies sand

and gravel of variable thickness. Origin: Distal foreset beds overlying proximal 

deltaic deposits

Sand and gravel overlying sand overlying fine overlying sand and gravel—Sand 

and gravel less than 20 feet thick and horizontally bedded overlies thicker, inclined layers 

of sand; these overlie silt and clay of variable thickness and sand and gravel of variable 

thickenss. Origin: Deltaic deposits overlying lake-bottom deposits overlying proximal 

lacustrine fan deposits

Sand overlying fine overlying sand and gravel—Thin sand overlies thicker silt and 

clay of variable thickness and sand and gravel of variable thickness. Origin: Deltaic 

deposits overlying lake-bottom deposits overlying proximal lacustrine fan deposits

Sand and gravel overlying sand overlying fine—Sand and gravel less than 20 feet 

thick, horizontally bedded overlies thicker, inclined layers of sand; these overlie silt and 

clay and locally very fine sand and silt of variable thickness. Origin: Deltaic deposits

overlying lake-bottom deposits and distal lacustrine fan sediments

Sand overlying fines—Thin sand overlies thicker silt and clay and locally very fine sand 

and silt. Origin: Deltaic foreset beds overlying lake-bottom deposits and distal lacustrine 

fan sediments

Glacial-ice-laid deposits—Includes deposits laid down beneath the ice sheet as lodgement till or melted 

out of the ice as ablation till; also material melted out or shoved into place at the terminus of the ice sheet 

as end moraine deposits

Till—Nonsorted, nonstratified mixture of sand, silt, and clay containing scattered 

pebble, cobble, and boulder clasts; large surface boulders are common; mapped where till 

is generally less than 10 to 15 feet thick. Predominantly upper till of the last glaciation; 

loose to moderately compact, generally sandy,commonly stony. Two facies 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. A darker green color (tt) indicates areas where till is greater than 10 to 15 

feet thick, chiefly in drumlin landforms in which till thickness commonly exceeds 100 

feet. 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

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 and shown on map 

as tiangle-patterned areas. Deposits occur as free-standing hummocky landform and 

range in thickness from 10 to 60 feet. Origin: Deposits laid down by ablation at the front 

of the retreating ice margin in the Wolf Rocks and Congdon Hill moraines

Till overlying sand and gravel—Ablation till and some lodgement till overlying 

deformed glacial meltwater sediments. In the gravel pit south of Genesee Brook, till 

ranges from about 3 ft to as much as 10 feet in thickness. Origin: Readvance of the ice 

sheet over previously deposited deltaic deposits 

sg

s

f

 sg 

s

s

sg

sg

s

f

s

f

tt

t

em

t

sg

sb

af

al

sw

Location of wells used in mapping

SCALE 1:24,000

1 0.5 0 1 MILE

1 0.5 0 1 KILOMETER

CONTOUR INTERVAL 10 FEET

Base from U.S. Geological Survey 1:24,000 topographic maps, 1995 and 2001

Shaded relief from Rhode Island Geographic Information System, 1-meter resolution

bare-earth digital elevation model from statewide lidar data, 2011

Rhode Island State plane projection

North American Datum of 1983

Surficial materials units mapped by J.R. Stone; 

basic geologic units modified from Kaye, 1960, 

Power, 1957, and Schafer, 1961

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

endorsement by the U.S. Government.

Digital files available at http://pubs.usgs.gov/sir/2014/5216/.

Suggested citation:

Stone, J.R., 2014, Surficial materials map of the Chipuxet River and Chickasheen Brook Basins, Rhode, Island, pl. 1 of

Areas contributing recharge to production wells and effects of climate change on the groundwater system in the 

Chipuxet River and Chickasheen Brook Basins, Rhode Island: U.S. Geological Survey Scientific Investigations Report 

2014−5216, 56 p, 1 pl., http://dx.doi.org/10.3133/sir20145216.

ISSN 2328-0328 (online)

Surficial Materials Map of the Chipuxet River and Chickasheen Brook Basins, Rhode Island

By

Janet Radway Stone

2014

71°30'0"W

71°30'0"W

71°35'0"W 71°32'30"W

41°32'30"N 41°32'30"N

41°30'0"N 41°30'0"N

41°27'30"N

41°25'0"N 41°25'0"N

71°35'0"W 71°32'30"W

41°27'30"N

Prepared in cooperation with the

Rhode Island Department of Health

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2014–5216

Plate 1 of 1