B B'

A'

A

C

C'

McMinnville Dayton St Paul

Lake

Oswego

West Linn

Gladstone

Wilsonville

Tualatin

Mount

Angel

Woodburn

Gervais

Molalla

SALEM

Dallas

Eola

Turner

Falls

City

Monmouth

Albany

Tangent

Brownsville Halsey

Independence

Sweet

Home 

Corvallis

Lebanon

Monroe

Harrisburg

Eugene Veneta

Junction

City

Coburg

Santa

Clara

Springfield

Creswell Lowell

Cottage

Grove

Tigard

Sheridan

Philomath

North

Albany

Hayesville

Clackamas

Sherwood

Oregon

City

Canby

Aurora

Newberg

Carlton

Gaston

Amity

Silverton

Scotts Mills

Keizer

Stayton

Scio

Jefferson

Sidney

Sublimity

Lyons

Mill

City

M A R K S R I D G E

Turner

Gap

SALEM

HILLS

Willamette

Falls

Rock Creek

Gap

E O L A H I L L S

E O L A H I L L S

W A L D O H I L L S

W A L D O

H I L L S

CLACKAMAS COUNTY

MARION COUNTY

WASHINGTON

COUNTY

MULTNOMAH

COUNTY

YAMHILL COUNTY

POLK COUNTY

POLK COUNTY

BENTON COUNTY

BENTON COUNTY

LANE COUNTY

LINN COUNTY

LINN COUNTY

MARION COUNTY

LANE COUNTY

TILLAMOOK

COUNTY

Willamette basin boundary

River

Panther

Muddy

Baker

Deer

Turner

Haskins

Creek

Creek

Creek

Creek

Creek

Creek

River

River

Champoeg

Palmer

Creek

River

Pudding

Mill Creek

Creek

Creek

Slough

Ash

N Fk

Ash

S Fk

Creek

Creek Swale

Clear

Creek

River

Creek

Creek

Creek

Butte

Coal

Creek

Abiqua

Butte

River

Pudding

Creek

Creek

North 

Thomas 

N Fk

S Fk

Thomas

Sucker

Creek

Slough

Jordan

Fork

Creek

Neal

Neal Cr

Roaring

Crabtree

Mill

Creek

Creek

Creek

Creek

Ella

River

Creek

Crabtree

Creek

Cr

Creek

Beaver

Hamilton

Creek

Scott

Creek

Creek

S Fk

Creek

Creek

Mill

Drift

River

Branch

Bear

River

Silver

Beaver

Luckiamute

Santiam

Little

Stout

North

North

Santiam River

Santiam

Green Peter

Lake

South

River

Calapooia

Creek

River

Courtney

River

Muddy

Muddy

Parsons

McGowan

Cash

Creek

Pierce

Creek

Creek

Creek

Creek

Creek

Creek

Hills

Creek

Creek

Fall

Little

Lake

Reese

Creek

Marys

River

Calapooia

Muddy

River

Oak

Butte

Lake

Creek

Creek

Creek

Cox

Creek

Fern

Ridge

Lake

Creek

River

Creek

Amazon

Tom

Creek

Creek

Creek

Creek

Owens

Bear

Inman

Creek

Flat

Dry

Muddy

Creek

Ferguson

Long

Tom

Long

River

Creek

Little

Creek

Fall

Camp

Mohawk

Papenfus

Bear

Camas Swale

Middle

River

Creek

Creek

Creek

Creek

Creek

Gettings

Creek

Creek

River

Silk

Mosby

Martin

Drue

Big

Creek

Creek

River

Creek

Cr

Row

Lost

Fall Creek

Lake

Dexter

Lake

Lookout

Point

Lake

Dorena

Lake

Coast

River

Fork

Cottage

Grove

Lake

Abernethy

Creek

Clackamas

Rock

Rock

River

Gribble

Bear

Creek

Creek

Creek

Creek

Molalla

Chehalem

Creek

North Yamhill

South

Creek

WILLA

METTE

RIVER

Salt

River

Yamhill

Rickreall

W Fk Salt Cr

Little

Baskett

Luckiamute

Battle Creek

Creek

Little Pudding

River

North

River

Cr

River

Soap

Berry

Creek

Cr

Creek

Cr

Cooper

Creek

Jont

Spring

Valley

Creek

Middle Santiam

C

River

reek

Creek

Greasy

Beaver

Muddy

Dixon

Creek

Spoon

Creek

Creek

McDowell

Green Mountain Creek

Indian Prairie Cr

Ames Creek

Wiley Creek

McKenzie

Mill

Coyote

Creek

Yamhill

Tualatin

Cedar Creek

Mission

Creek

Winberry Creek

Willamette

Rattlesnake

Fork

Labish Channel

McKinney Creek

Chehulpum

Santiam River

River

WILLAMETTE

Hammer Creek

RIVER

Wilson

Willamette

Lake Oswego

Foster Lake

Tvc

Tm

Tm

Tm

Tm

Qff2

Qff2

Qff2

QTt

QTt Tm

QTg

QTg

QTg

QTg

Qalf

QTg

Tm

Tm

Tm

Tm

Tm

Qff2

Qff2

Qff2

Tcr

Tcr

Tcr

Tcr

Tcr

Qau

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qff2

Tcr

Qls

Qff2

Qff1

Qff1

Qff1

Tm

Qff2

Tm

Qff2

Qff2

Qff2

Qff2

Qff2 Qff2

Qff2

Tcr

Tcr

Qalf

Qau

Qfc

Qfc

Qfc

Qfc

Qfc

Qau

Tcr

Tcr

Qalf

Qalf

QTt

QTt QTt

QTt

Qff2

Qff2

Qff2

Qalf

Qalc

Qalc

Qalc

Qalc

QTg

QTg

QTg

QTb

QTb

QTb

QTb QTb

QTt

Qau

QTb

Qau

Qau

Qg1

Qg1

Qg1

Tcr

Tcr

Tvw

Tvw

Qau

Qau

Qau

Qau

Qau

Qau

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr Tcr

Tcr

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tvw

Tvw

Tvw

Qbf

Qbf

Qbf

Qbf

Qbf

Qbf

Qbf

Qbf

Qbf

Qbf

Qbf

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qalc

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qau

Qff2

Qff2

Qff2

Qff2

Qff2 Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

Qff2

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg QTg

QTg

QTg

QTg

QTg

QTg

Qau

QTg

Qalc

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

QTg

Qff1

Qff1

Qff1

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalf

Qalc

Qalc

Qalc

Qalc

Qalc

Qalc

Qalc

Qalc

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1 Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qg1

Qls

Qls

Qls

Qls

Qls

Qls

Qls

Qls

Qls

Qls

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr

Tcr

Tm

Tm

Tm

Tm

Tm Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm Tm

Tm

Qau

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Qau

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tm

Tvc

Tvc

Tvc

Tvc

Tvc

Tvc

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Tvw

Qg2

Qg2

Qg2

Qg2

Qg2

Qg2

Qg2

Qg2

Qg2

Qg2

Qg2

Qg2

Wildish

S&G

Delta

S&G

Cartney

Park

Irish

Bend

Bear

Island

Sidney

Wheatland

Ferry

River

Bend

Weston

Landing

Walling

S&G

River

Bend

S&G

RM

50

RM

30

RM

40

RM

60

RM

70

RM

80

RM

90

RM

100

RM

110

RM

120

RM

130

RM

140

RM

150

RM

160

RM

170

RM

180

RM

190

RM

200

VK

25

VK

50

VK

75

VK

100

VK

125

VK

150

VK

175

VK

200

VK

225

Sidney

RM

110

VK

125

5

5

205

22

22

20

5

126

126

20

5

99W

99W

99W

99

99

99E

99E

99E

99E

5

26

26

20

5

5

84

126

22

20

126

22

30

M U L T N O M A H

C O L U M B I A

W A S H I N G T O N

C L A C K A M A S

P O L K

L I N N 

L A N E

M A R I O N 

Y A M H I L L 

D O U G L A S

D O U G L A S

B E N T O N

Study area

boundary

South

River

Keizer

SALEM

NORTHERN

VALLEY

WILLAMETTE

STAYTON

SUBBASIN

SOUTHERN

WILLAMETTE

VALLEY

BASIN

Willamette

basin boundary

Clackamas

C O L U

M B I A

Luckiamute Luckiamute

RIVER

Middle Santiam

River

Middle Santiam

River

N Fk

M Fk

Willamette

North

Santiam

River

North

River

Bull

Run River

River

River

Molalla

Sandy River

River

River

McKenzie

Middle

Fork

Tualatin

River

South

R I V E R

River

Waldo

Lake

Hills

Creek

Lake

Lookout

Point

Lake

Fall Creek

Lake

Dorena

Lake

Blue River

Lake

Cougar

Reservoir

Foster

Lake

Green

Peter

Lake

Detroit

Lake

Timothy

Lake

Henry

Hagg

Lake

Fern

Ridge

Lake

Bull Run

Lake

Marys

River

R Tom

Long

WILLAMETTE WILLAMETTE

YamhillYamhill River

River Yamhill Yamhill

SantiamSantiam

Calapooia Calapooia

Willamette RiverWillamette River

Coast Fork Coast Fork

River

Willamette

Willamette Willamette

River

River

Pudding Pudding

10 20 MILES

0 10 20 KILOMETERS

0

44o

43o30' 43o30'

44o

45o

45o30' 45o30'

45o

123o

123o

Base composited from USGS digital line graphs 

and other digital information. Universal Transverse 

Mercator projection, Zone 10, North American 

Datum 1927 

5 205

Mt

Jefferson

North

Sister

Middle

Sister

South

Sister

Mt

Hood

Gresham

Woodburn

Silverton

Hubbard

St Paul

Eugene

Springfield

Junction

City

Harrisburg

Halsey Brownsville

Albany

Corvallis

Cottage

Grove

Detroit

Milwaukie

Sandy

Estacada

Oregon

City

West Linn

Beaverton

Hillsboro Forest

Grove

Newburg

McMinnville

Dallas

PORTLAND

Tualatin

Sherwood

Sheridan

MonmouthBuena

Vista

Independence

Stayton

Mount

Angel

St Helens

Scappoose

Lebanon

Sweet

Home

Amity

C

A

S

C

A

D

E

R

A

N

G

E

C

O

A

S

T

R

A

N

G

E

122o

122o

44o30' 44o30'

Tualatin Mountains

Chehalem Mountains

PORTLAND

Study OREGON area

Willamette

basin

Crater

Lake

Portland

Cottage

Grove

Lake

16

17

13

19

15

6

4

1

2

11

9

5

8

7

14

3

10

12

18

SOURCES OF GEOLOGIC MAPPING

EXPLANATION

1 Allison (1953)

2 Allison and Felts (1956)

3 Balster and Parsons (1968)

4 Bela (1979)

5 Bela (1981)

6 Beaulieu and others (1974)

7 Brownfield and Schlicker (1981a)

8 Brownfield and Schlicker (1981b)

9 Frank (1973)

10 Frank (1974)

11 Frank (1976)

12 Gannett and Caldwell (1998)

13 Glenn (1965)

14 Hampton (1972)

15 Piper (1942)

16 Price (1967a)

17 Price (1967b)

18 Trimble (1963)

19 Yeats and others (1996)

Not shown are the Geologic Map of Oregon 

(Walker and MacLeod, 1991), and the Soil 

Conservation Service (now Natural Resources 

Conservation Service) soil surveys for each of the 

counties within the map area (Williams, 1972; 

Otte and others, 1974; Knezevich, 1975, 1982; 

Gerig, 1985; Langridge, 1987; Patching, 1987).

Source map number and authors—Full reference citation 

at back of text

LOCATION MAP

INDEX MAP

CORRELATION OF MAP UNITS

0

0.01

1.6

5.0

24

38

Age (Ma)

Pliocene

Miocene

Oligocene

Eocene

TERTIARY QUATERNARY

Holocene

Pleistocene

Qau Qbf Qls

QTg

QTt QTb

Tcr

Tvw

Tm

Tvc

Unconformity

Qalf Qalc

Qg1

Qff2 Qfc

Qff1

Qg2

Disconformity

Disconformity

Disconformity

Disconformity

Conformity to Disconformity

Unconformity

A A'

DESCRIPTION OF MAPPING UNIT

Water

Contact

Alluvium of smaller streams (Holocene and upper Pleistocene)—Unconsolidated clay, silt, sand, and minor gravel 

deposited in floodplains and active channels of smaller streams and rivers. Variable surface morphology. Thickness not 

defined, but probably less than 10 meters. Differentiated from units Qbf and Qau where clearly younger than Missoula 

Flood deposits. Mostly younger than 12 ka.

Floodplain deposits of the Willamette River and major tributaries (Holocene and upper Pleistocene)— 

Unconsolidated silt, sand, and gravel of the Willamette River and major Cascade Range tributaries. Includes active 

channel and modern floodplain surfaces. Meander-scroll topography with surfaces as high as 15 meters above summer 

water stage. Drillers' logs and exposures indicate that unit thickness ranges up to 15 meters. Isotopic dating, 

tephrochronology, and stratigraphic relations within the Willamette Valley indicate that these deposits are mostly younger 

than 12 ka.

Sand and Gravel that postdates Missoula Floods (upper Pleistocene)—Alluvial sand and gravel deposited in broad 

braidplains within Willamette Valley and traced upstream as alluvial fills in major Cascade Range tributary valleys. Forms 

surfaces of large fans where major Cascade Range tributaries enter the Willamette Valley. Deposits now preserved as 

planar to slightly undulating terraces 0 to 15 meters above the modern floodplain. Drillers' logs and stratigraphic exposures 

indicate that unit is up to 30 meters thick. Stratigraphic relations and isotopic dating indicate that deposits primarily date 

from about 12 ka, although some areas mapped as Qg1 in the Eugene-Springfield area and within the Cascade Range 

foothills may be substantially older.

Missoula Flood deposits (upper Pleistocene)—Unconsolidated clay, silt, sand, and gravel deposited by floods 

originating in glacial Lake Missoula that flowed down the Columbia River and backflooded into the Willamette Valley 

(Glenn, 1965; Allison, 1978). Largest flows reached stages of about 120 meters above sea level in the map area. 

Maximum thickness of deposits about 35 meters in northern Willamette Valley, thins to less than 1 meter at elevations 

above about 100 meters. Radiocarbon dating, tephrochronology, and stratigraphic relations from within and outside the 

map area indicate that most units date from about 15 to 12.7 ka. Divided into:

Younger and lower fine-grained Missoula Flood deposits—Clay, silt, sand, and minor gravel forming benches along 

Labish channel and Pudding River, and locally flanking Willamette River in northern Willamette valley. Planar to 

undulating surface almost everywhere 40-50 meters above sea level. Set into main-body fine facies (Qff2). Probably 

mostly deposited by latest Pleistocene Missoula Floods between 13.5 and 12.7 ka, but possibly includes late Pleistocene 

and early Holocene deposits of units Qalf and Qalc.

Main body of fine-grained Missoula Flood deposits—Stratified silt and clay with minor sand. Underlies much of 

Willamette Valley lowland floor. Many sections show rhythmic bedding, with up to 40 individual beds between 0.1 and 

1.0 meter thick. Encloses sparse pebbles to boulders of types exotic to Willamette Basin. Forms undulating to planar 

topography in lowlands; mantles foothills below altitudes of 120 meters. Mapped where thickness is sufficient to 

obscure previous topography. Commonly capped by up to two meters of late Pleistocene and Holocene alluvium, 

colluvium, and loess.

Coarse Missoula Flood deposits—Bouldery, cobbly, sandy gravel fans deposited by Missoula Floods as they spilled 

into northern Willamette Valley through the Oregon City and Rock Creek gaps. Crudely stratified, commonly with 

south-dipping foresets. Commonly capped by several meters of sandy silt, especially south of Willamette River. Drillers' 

logs indicate that thickness locally exceeds 30 meters.

Sand and gravel that predates Missoula Floods (Pleistocene)—Unconsolidated to semiconsolidated sand and gravel 

deposited in broad braidplains and meandering floodplain environments within Willamette Valley and upstream as alluvial 

fills along major Cascade Range tributaries. Locally contains lahar deposits. Forms planar to slightly undulating terrace 

surfaces 0 to 20 meters above the modern floodplain and generally at slightly higher elevations than adjacent surfaces of 

unit Qg1. Thickness not systematically determined but locally exceeds 100 meters in broad fans formed where major 

Cascade Range tributaries enter the Willamette lowlands. Isotopic dating and tephrochronology indicate these deposits 

range from greater than 0.41 Ma to about 22 ka.

Alluvium, undifferentiated (Holocene and Pleistocene)—Sand, silt, clay, and minor gravel deposited by smaller streams 

and rivers that enter the Willamette Valley, and by larger streams and rivers outside the area of detailed mapping. Age and 

thickness not determined.

Fine-grained alluvium (Holocene and Pleistocene)—Clay, silt, sand, and minor gravel deposited in small basins 

flanking the Willamette Valley. Planar surfaces. Age and thickness not determined. Distinction with unit Qau locally 

arbitrary.

Landslide deposits and colluvium (Holocene and Pleistocene)—Unconsolidated and heterogeneous mixtures of rock 

fragments and soil. Some landslide deposits have hummocky surfaces. Colluvium mapped on steep debris-mantled slopes 

where underlying bedrock is not known. Only larger deposits mapped, mostly after Walker and McLeod (1991). Age and 

thickness not defined.

Weathered terrace gravel (Pleistocene and Pliocene?)—Alluvial sand and gravel preserved as terraces flanking 

Willamette Valley and tributary valleys. Terrace surfaces planar to undulating, with thick, strongly-developed soils, and 

severely weathered clasts. Terrace surfaces up to 100 meters above modern floodplains. Drillers' logs and stratigraphic 

exposures indicate sand and gravel 0 to 60 meters thick. May be in part equivalent to Troutdale Formation (QTt) as 

mapped near Molalla. Probably mostly deposited between 2.5 and 0.5 Ma.

UPLAND UNITS (Primarily compiled from previous workers)

Boring Lava (Pleistocene and Pliocene)—Gray to light-gray, open-textured olivine basalt lava flows. Only mapped in 

the northern part of map area after Hampton (1973). Up to 60 meters thick. Ten radiometric ages on separate flows near 

Oregon City span 0.427 ± 0.026 Ma to 3.15 ± 0.062 Ma (Madin, 1994).

Troutdale Formation (Pleistocene? and Pliocene)—Sand, gravel, sandstone, conglomerate, siltstone, and mudstone. 

Only mapped in northern part of map area after Trimble (1963) and Hampton (1972) where it is up to 150 meters thick. 

May be locally equivalent to the weathered terrace gravel (QTg) near Molalla. Overlain by Boring Lava near Oregon City.

Volcanic and volcaniclastic rocks of the western Cascade Range, undivided (upper Eocene to Pliocene)—Lava flows, 

tuff, breccia, and volcaniclastic sediment of variable composition. Locally interfingers with marine sedimentary rocks (Tm) 

in the southern portion of map area. Includes the Fisher Formation, "volcanic rocks of the western Cascade Range", and 

Sardine Formation as compiled by Gannett and Caldwell (1998). Youngest rocks are ridge-capping basalt flows in Santiam 

River drainage with reported ages as young as 2.80 ± 0.3 Ma (Verplanck, 1985, cited in Walker and Duncan, 1989).

Columbia River Basalt Group (Miocene)—Lava flows of dark gray to black, locally porphyritic basalt. Locally deeply 

weathered. Mostly between 16 and 15 Ma in northern Willamette Valley (M.H. Beeson, Portland State University, written 

communication, 1998). Also includes small areas of alluvium, colluvium, loess, and landslide debris. Distribution after 

Gannett and Caldwell (1998).

Marine sedimentary rocks (lower Miocene to Eocene)—Marine sandstone, siltstone, shale, and claystone, with lesser 

conglomerate; locally tuffaceous. Also includes numerous small mafic intrusions, and small areas of alluvium, colluvium, 

loess, and landslide debris. Distribution after Gannett and Caldwell (1998).

Volcanic rocks of the Coast Range (Eocene)—Basaltic pillow lava, tuff breccia, subaerial basalt lava flows, and sills, with 

interbeds of basaltic sandstone, siltstone, and conglomerate. Includes small areas of alluvium, colluvium, loess, and 

landslide debris. Distribution after Gannett and Caldwell (1998).

Note: "Ma" refers to millions of years before present, and in this report is used to indicate radiometric and fission track ages 

on volcanic rocks. "ka" refers to kiloannum, indicating thousands of radiocarbon years before present.

River mile location—From US Geological Survey 1:24,000-scale 

topographic quadrangles

Valley kilometer—Measured from Columbia River confluence along axis of 

Holocene floodplain of the Willamette River

Site location—Stratigraphic section or sample site described in accompanying text.

Note: "S&G" = Sand and Gravel.

Trace of generalized geologic sections shown on figure 2 of the report

Study area boundary

Qalf

Qalc

Qau

Qbf

Qg1

Qg2

Qls

Qff1

Qff2

Qfc

Tcr

Tm

Tvc

QTg

QTb

QTt

Tvw

Base compiled from U.S. Geological Survey digital base, includes:

U.S. Geological Survey Digital Line Graphs published at 1:100,000, 1987;

U.S. Bureau of the Census TIGER/Line® files, published at 1:100,000, 1990;

U.S. Geological Survey Digital Line Graphs published at 1:100,000, 1988

 and modified by the State of Oregon, 1994;

U.S. Geological Survey quadrangle topographic maps published at 1:24,000

 as digitized by Oregon Department of Transportation

Projection: Universal Transverse Mercator projection, Zone 10, 1927 North American Datum

GEOLOGIC MAP OF QUATERNARY UNITS IN THE WILLAMETTE VALLEY, OREGON

By

Jim E. O'Connor, Andrei Sarna-Wojcicki, Karl C. Wozniak, Danial J. Polette, and Robert J. Fleck

2001

Geologic unit linework was compiled and digitized at a scale of 1:24,000, but 

the accuracy of the contacts varies depending on location and geologic unit.

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

PROFESSIONAL PAPER 1620

Quaternary geologic units in Willamette Valley, Oregon—PLATE 1

Prepared in cooperation with

OREGON WATER RESOURCES DEPARTMENT

43°45'

44°00'

44°15'

44°30'

44°45'

45°00'

SCALE 1:250,000

0 5 10 15 MILES

0 5 10 15 KILOMETERS

123o30' 123o15' 123°00' 122°45'

123°45'

123°45' 123°30' 123°15' 123°00' 122°45'

45°15'

43°45'

44°00'

44°15'

44°30'

44°45'

45°00'

45°15'

R. 3 W. R. 2 W.

R. 7 W. R. 6 W. R. 5 W. R. 4 W. R. 3 W. R. 2 W. R. 1 W. R. 1 E. R. 2 E. R. 3 E.

R. 7 W. R. 6 W. R. 5 W. R. 4 W. R. 1 W. R. 1 E. R. 2 E. R. 3 E.

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O'Connor and others, 2001, Origin, Extent, and Thickness of 

Quaternary Geologic Units in the Willamette Valley, Oregon.