National Park Service

U.S. Department of the Interior

Natural Resource Stewardship and Science

Ebey’s Landing National Historical Reserve

Geologic Resources Inventory Report

Natural Resource Report NPS/NRSS/GRD/NRR—2011/451
ON THE COVERS

Ebey’s Landing National Historical Reserve is 

the first such unit of the National Park 

System. It encompasses a rural working 

landscape and community on Whidbey 

Island, Washington State.

Photographs by Emi Gunn, courtesy

Lys Opp-Beckman (Ebey’s Landing NHR).
Ebey’s Landing National Historical Reserve

Geologic Resources Inventory Report

Natural Resource Report NPS/NRSS/GRD/NRR—2011/451

National Park Service

Geologic Resources Division

PO Box 25287

Denver, CO 80225

September 2011

U.S. Department of the Interior

National Park Service

Natural Resource Stewardship and Science

Fort Collins, Colorado
ii NPS Geologic Resources Division 

The National Park Service, Natural Resource Stewardship and Science office in Fort 

Collins, Colorado publishes a range of reports that address natural resource topics of 

interest and applicability to a broad audience in the National Park Service and others in 

natural resource management, including scientists, conservation and environmental 

constituencies, and the public. 

The Natural Resource Report Series is used to disseminate high-priority, current natural 

resource management information with managerial application. The series targets a 

general, diverse audience, and may contain NPS policy considerations or address 

sensitive issues of management applicability.

All manuscripts in the series receive the appropriate level of peer review to ensure that 

the information is scientifically credible, technically accurate, appropriately written for 

the intended audience, and designed and published in a professional manner. This 

report received informal peer review by subject-matter experts who were not directly 

involved in the collection, analysis, or reporting of the data.

Views, statements, findings, conclusions, recommendations, and data in this report do 

not necessarily reflect views and policies of the National Park Service, U.S. Department 

of the Interior. Mention of trade names or commercial products does not constitute 

endorsement or recommendation for use by the U.S. Government.

Printed copies of this report are produced in a limited quantity and they are only 

available as long as the supply lasts. This report is available from the Geologic Resources 

Inventory website 

(http://www.nature.nps.gov/geology/inventory/gre_publications.cfm) and the Natural 

Resource Publications Management website 

(http://www.nature.nps.gov/publications/nrpm/). 

Please cite this publication as:

Graham, J. 2011. Ebey’s Landing National Historical Reserve: geologic resources 

inventory report. Natural Resource Report NPS/NRSS/GRD/NRR—2011/451. 

National Park Service, Fort Collins, Colorado.

NPS 484/110343, September 2011
EBLA Geologic Resources Inventory Report iii

Contents

List of Figures................................................................................................................ iv

List of Tables ................................................................................................................. iv

Executive Summary ....................................................................................................... v

Acknowledgements...................................................................................................... vi

Credits........................................................................................................................................................................ vi

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

Purpose of the Geologic Resources Inventory ...............................................................................................................1

Significance of Ebey’s Landing National Historical Reserve ............................................................................................1

Regional Description ....................................................................................................................................................1

Geologic Setting ..........................................................................................................................................................2

Cultural History ............................................................................................................................................................2

Geologic Issues .............................................................................................................. 9

Shoreline Erosion and Bluff Retreat ..............................................................................................................................9

Groundwater Resources...............................................................................................................................................9

Seismic (Earthquake) Potential....................................................................................................................................10

Glacier Peak Eruptive Potential ...................................................................................................................................11

Climate Change .........................................................................................................................................................11

Other Issues...............................................................................................................................................................12

Geologic Features and Processes................................................................................ 17

Glacial Features and Processes....................................................................................................................................17

Post-glacial Features and Processes.............................................................................................................................20

Paleontological Resources ..........................................................................................................................................20

Landscape Character Areas ........................................................................................................................................21

Geologic History .......................................................................................................... 29

Geologic Map Data...................................................................................................... 35

Geologic Maps...........................................................................................................................................................35

Source Maps..............................................................................................................................................................35

Geologic GIS Data......................................................................................................................................................35

Geologic Map Overview.............................................................................................................................................36

Map Unit Properties Table..........................................................................................................................................36

Use Constraints..........................................................................................................................................................36

Geologic Map Overview Graphic................................................................................ 37

Map Unit Properties Table .......................................................................................... 39

Glossary........................................................................................................................ 45

Literature Cited............................................................................................................ 49

Additional References ................................................................................................. 53

Geology of National Park Service Areas......................................................................................................................53

Resource Management/Legislation Documents...........................................................................................................53

Geological Survey and Society Websites.....................................................................................................................53

Other Geology/Resource Management Tools..............................................................................................................53

Appendix: Scoping Session Participants .................................................................... 54

Attachment 1: Geologic Resources Inventory Products CD
iv NPS Geologic Resources Division 

List of Figures

Figure 1. Location map of Ebey’s Landing National Historical Reserve............................................................................4

Figure 2. Whidbey Island map ......................................................................................................................................5

Figure 3. Whidbey Island bluffs. ...................................................................................................................................6

Figure 4. Geologic cross-section A–A’...........................................................................................................................6

Figure 5. General stratigraphic column for Ebey’s Landing National Historical Reserve...................................................7

Figure 6. Lidar-based image of glacial features associated with Ebey’s Landing National Historical Reserve ....................8

Figure 7. Steep shoreline bluffs at Ebey’s Landing National Historical Reserve..............................................................13

Figure 8. Schematic northwest—southeast geologic cross-section...............................................................................14

Figure 9. Partially excavated log in the low intertidal zone at the northwestern end of Penn Cove ...............................15

Figure 10. Blowers Bluff.............................................................................................................................................16

Figure 11. The Olympia nonglacial interval exposed at the top of Blowers Bluff...........................................................22

Figure 12. Relationship between high-energy gravel Partridge Gravel, and glaciomarine drift......................................23

Figure 13. Sedimentary features in the bottom-set beds of Partridge Gravel................................................................23

Figure 14. Kame-delta top-set and foreset sand and gravel beds in the Partridge Gravel .............................................24

Figure 15. Northwest-trending shoreline at Cedar Hollow...........................................................................................25

Figure 16. Shear planes in thePartridge Gravel............................................................................................................26

Figure 17. Coupeville moraine exposed in a road cut along Broadway Street in Coupeville ..........................................26

Figure 18. Paleosol beneath Holocene dune sand .......................................................................................................27

Figure 19. Mastodon tusk ..........................................................................................................................................27

Figure 20. Fossil fragments from dune sand ...............................................................................................................28

Figure 21. Geologic timescale.....................................................................................................................................31

Figure 22. Middle Jurassic paleogeographic map of western North America................................................................32

Figure 23. Pleistocene paleogeographic map of North America...................................................................................33

List of Tables

Table 1. Landscape Character Areas and Geologic Features. .......................................................................................28

Table 2. Geology data layers in the Ebey’s Landing National Historical Reserve GIS data..............................................36
EBLA Geologic Resources Inventory Report v

Executive Summary

This report accompanies the digital geologic map data for Ebey’s Landing National 

Historical Reserve in Washington, produced by the Geologic Resources Division in 

collaboration with its partners. It contains information relevant to resource management 

and scientific research. This document incorporates preexisting geologic information and 

does not include new data or additional fieldwork.

Ebey’s Landing National Historical Reserve has the 

distinction of being the first national historical reserve in 

the National Park System. Authorized in 1978, the 

reserve preserves and protects an unbroken historical 

record of Puget Sound exploration and settlement from 

the 19th century to the present. Located on Whidbey 

Island, the largest island in the conterminous United 

States, Ebey’s Landing National Historical Reserve lies 

about 43 km (27 mi) north of Seattle. Members of the 

central Whidbey Island community work together with 

local, state, and federal governments to manage the 

reserve and to balance the needs of the community with 

the protection of the reserve’s resources. 

The reserve lies in Washington’s Puget Lowland 

physiographic province, a broad, low-lying region 

between the Cascade Range to the east and the Olympic 

Mountains to the west. Like the San Juan Islands, the 

geomorphic features on Whidbey Island were shaped by 

continental glaciers that advanced over the Puget 

Lowland during the Pleistocene ice ages. Glacial and 

nonglacial units of clay, silt, sand, and gravel record the 

advance and retreat of several glaciers through the 

lowland. Ice from the most recent glaciation covered the 

area approximately 18,000 years ago. At the height of this 

glaciation, Whidbey Island was covered with about

1,250 m (4,100 ft) of ice. Upon melting, the glaciers left a 

mixture of unconsolidated sediments that reflect a 

variety of depositional environments including 

glaciomarine seafloors, deltas, fluvial outwash plains, and 

ice-margin and sub-glacial environments.

Shoreline and bluff erosion of these unconsolidated 

deposits, potable groundwater withdrawal from these 

units, and potential seismic activity are three geologic 

issues that may impact Ebey’s Landing National 

Historical Reserve. All of the shoreline bluffs, especially 

those along the western shore, are subject to constant 

erosion by high waves during storm events. Active 

erosion not only causes episodic landsliding and bluff 

retreat, but also affects archaeological sites. The most 

common American Indian archaeological sites on 

Whidbey Island are shell middens, the majority of which 

are found along marine shorelines in unconsolidated 

sediments. Most of these sites on Whidbey Island are 

actively eroding.

The primary recharge mechanism for the groundwater 

system on Whidbey Island is the percolation of 

precipitation through the heterogeneous glacial and 

nonglacial deposits. Because Whidbey Island lies in the 

rain shadow of the Olympic Mountains, less 

precipitation falls than expected, and most is lost to 

runoff, transpiration by plants, or evaporation. 

Percolation is further hindered by layers of lowpermeability glacial sediments.

The potential for saltwater intrusion of Whidbey Island’s 

sole source groundwater aquifer complicates the 

groundwater system, especially with respect to the 

growing population of the island and increased demand 

for freshwater. Saltwater contamination has been 

documented in the reserve and will continue to replace 

freshwater if pumping exceeds the rate of aquifer 

recharge. Development on the island may negatively 

impact the aquifer through increased saltwater intrusion 

and the introduction of nitrates, pesticides, and other 

contaminants. 

Whidbey Island lies in an active tectonic area, and coseismic tectonic land-level change has been documented 

within Ebey’s Landing National Historical Reserve. The 

northwest-trending Southern Whidbey Island fault lies 

10 km (6 mi) southeast of Admiralty Head, which forms 

the southwestern corner of the reserve. This fault 

separates two major crustal blocks and has been the 

source of several historic shallow earthquakes. Faults 

identified outside of the reserve indicate fault movement 

as recently as 1850 C.E. (Common Era; preferred to 

“A.D.”). Most of Ebey’s Landing National Historical 

Reserve is pastoral, but tectonic land-level changes and 

ground shaking from earthquakes are potential hazards 

to the historic buildings in Coupeville, the second oldest 

town in Washington and the commercial center of the 

reserve. Coupeville is built over clayey glaciomarine drift, 

which may not provide a firm foundation in the event of 

an earthquake.

Glaciers shaped the landforms on Whidbey Island and 

laid the foundation for the cultural history preserved at 

Ebey’s Landing National Historical Reserve. For 

example, the bluffs along the western shoreline provided 

an excellent vantage point for Fort Casey, built in the late 

1890s and currently preserved as a state park. Glacial till 

formed the rolling hills and agricultural lands of the San 

de Fuca Uplands. The clayey glaciomarine drift and 

gentle slopes left behind by the ice provided rich soils for 

the crops grown by American Indians and present-day 

farmers in Ebey’s Prairie, located in the central portion 

of the reserve. Smith Prairie formed as a well-drained, 

elevated, and flat glaciolacustrine delta surface that was 

an attractive site for the location of the Coupeville 
vi NPS Geologic Resources Division 

airfield. The embayment of Penn Cove, which provides a 

naturally sheltered harbor for Coupeville and is an ideal 

location for the cultivation of mussels, resulted from fastflowing, pressurized subglacial meltwater that carved a 

trough into the sediments between Coupeville and the 

uplands to the north. The formation of kettle ponds by 

the melting of stagnant ice shaped the landscape in the 

Kettle and Pratt Woodlands surrounding Fort Ebey State 

Park. 

This report includes a Map Unit Properties Table that 

describes characteristics such as erosion resistance, 

suitability for infrastructure development, geologic 

significance, recreation potential, and associated cultural 

and mineral resources for each geologic unit mapped in 

Ebey’s Landing National Historical Reserve. 

This report also provides a glossary, which contains 

explanations of technical, geologic terms, including those 

used on the Map Unit Properties Table. Additionally, a 

geologic timescale (fig. 21) shows the chronological 

arrangement of major geologic events, with the oldest 

events and time units at the bottom and the youngest at 

the top.

Acknowledgements

The Geologic Resources Inventory (GRI) is one of 12 inventories funded by the National 

Park Service Inventory and Monitoring Program. The GRI is administered by the 

Geologic Resources Division of the Natural Resource Stewardship and Science 

Directorate.

The Geologic Resources Division relies heavily on 

partnerships with institutions such as the U.S. Geological 

Survey, Colorado State University, state geologic surveys, 

local museums, and universities in developing GRI 

products.

Special thanks to: Michael Polenz (Washington State 

DNR) supplied a draft copy of the geologic field trip 

guide of the reserve as well as many of the photographs 

used in the report. Lys Opp-Beckman (Ebey’s Landing 

NHR) also provided images used on the covers and 

within the report.

Credits

Author

John P. Graham (Colorado State University)

Review

Michael Polenz (Washington State Department of 

Natural Resources)

Pat Pringle (Centralia College [Washington State])

Jason Kenworthy (NPS Geologic Resources Division)

Editing

Jennifer Piehl (Write Science Right)

Digital Geologic Data Production

Greg Mack (NPS Pacific West Region)

Stephanie O’Meara (Colorado State University)

Digital Geologic Data Overview Layout Design

Derek Witt (Colorado State University intern)

Philip Reiker (NPS Geologic Resources Division)

Georgia Hybels (NPS Geologic Resources Division)
EBLA Geologic Resources Inventory Report 1

Introduction

The following section briefly describes the National Park Service Geologic Resources 

Inventory and the regional geologic setting of Ebey’s Landing National Historical 

Reserve.

Purpose of the Geologic Resources Inventory 

The Geologic Resources Inventory (GRI) is one of 12 

inventories funded by the National Park Service (NPS) 

Inventory and Monitoring Program. The GRI, 

administered by the Geologic Resources Division of the 

Natural Resource Stewardship and Science Directorate, 

is designed to provide and enhance baseline information 

available to park managers. The GRI team relies heavily 

on partnerships with institutions such as the U.S. 

Geological Survey, Colorado State University, state 

geologic surveys, local museums, and universities in 

developing GRI products.

The goals of the GRI are to increase understanding of the 

geologic processes at work in parks and to provide sound 

geologic information for use in park decision making. 

Sound park stewardship requires an understanding of 

the natural resources and their role in the ecosystem. 

Park ecosystems are fundamentally shaped by geology. 

The compilation and use of natural resource information 

by park managers is called for in section 204 of the 

National Parks Omnibus Management Act of 1998 and in 

NPS-75, Natural Resources Inventory and Monitoring 

Guideline. 

To realize these goals, the GRI team is systematically 

conducting a scoping meeting for each of the 270 

identified natural area parks and providing a parkspecific digital geologic map and geologic report. These 

products support the stewardship of park resources and 

are designed for nongeoscientists. Scoping meetings 

bring together park staff and geologic experts to review 

available geologic maps and discuss specific geologic 

issues, features, and processes. 

The GRI mapping team converts the geologic maps 

identified for park use at the scoping meeting into digital 

geologic data in accordance with their Geographic 

Information Systems (GIS) Data Model. These digital 

data sets bring an interactive dimension to traditional 

paper maps. The digital data sets provide geologic data 

for use in park GIS and facilitate the incorporation of 

geologic considerations into a wide range of resource 

management applications. The newest maps contain 

interactive help files. This geologic report assists park 

managers in the use of the map and provides an overview 

of park geology and geologic resource management 

issues.

For additional information regarding the content of this 

report and current GRI contact information please refer 

to the Geologic Resources Inventory website 

(http://www.nature.nps.gov/geology/inventory/).

Significance of Ebey’s Landing National Historical 

Reserve 

Located on Whidbey Island at the entrance to Puget 

Sound, Ebey’s Landing National Historical Reserve is the 

nation’s first historical reserve (fig. 1). Public concern 

over the intent to develop three residential subdivisions 

on Ebey’s Prairie and adjoining farmland—nearly half of 

Whidbey Island’s total area—prompted Congress to 

establish the reserve in 1978 to preserve and protect the 

cultural landscape and to commemorate the history of a 

rural community. Ebey’s Landing National Historical 

Reserve provides a vivid and continuous historical 

record of exploration and American settlement in the 

Puget Sound region from the 19th century to the present. 

Most of the acreage included in the reserve is privately 

owned; only 1,096.18 ha (2,708.73 ac) of the reserve’s 

7,820.14 ha (19,323.99 ac) are federal (National Park 

Service 2004). The reserve contains two state parks, Fort 

Casey and Fort Ebey, and more than 6,500 pieces of 

private property, including the town of Coupeville, the 

county seat for Island County (Dietrich 2004). Because 

so much of the land was privately owned, the enabling 

legislation established the reserve as a non-traditional 

National Park Service unit to be managed by a unit of 

local government. To meet this requirement, the Trust 

Board of Ebey’s Landing National Historical Reserve was 

formed to manage the reserve. The National Park 

Service, local and state governments, and the residents of 

the central Whidbey Island community work 

collaboratively to help balance the needs of the 

community with the protection of the reserve’s 

resources.

Although the Puget Sound region is experiencing rapid 

economic development, Ebey’s Landing National 

Historical Reserve provides a broad spectrum of 

Northwest history that remains clearly visible within a 

large-scale (and partially protected) landscape. Rich 

prairie soils are still being farmed, forests are being 

harvested, and historic buildings are being used as homes 

or places of business just as they were a century ago, 

when New England sea captains were drawn to Penn 

Cove.

Regional Description

Whidbey Island is located about 43 km (27 mi) north of 

Seattle and 80 km (50 mi) south of the Canadian border. 

Extending nearly 64 km (40 mi) north-south and 1.6–16 

km (1–10 mi) east-west, Whidbey is the largest island not 

only in Puget Sound but also in the conterminous United 

States (fig. 2; National Park Service 2000). Like most 
2 NPS Geologic Resources Division

Puget Sound landforms, Whidbey Island is no higher 

than 150 m (500 ft) in elevation (fig. 3).

Ebey’s Landing National Historical Reserve occupies a 

narrow bend in central Whidbey Island. Approximately 

42% of the land is classified as “agricultural/open space” 

by Island County and is contained primarily within 

Smith, Crockett, and Ebey’s prairies (National Park 

Service 2000). Ebey’s Prairie is the largest open space in 

the reserve and contains the most productive agricultural 

land. About 36% of the reserve is classified as 

woodlands, 11.4% as residential, nearly 5% as wetland, 

and 1% as urban commercial space. 

The reserve has been divided into ten cultural landscape 

areas, recognizable by their distinctive landforms and 

critical landscape components (Gilbert, 1985; National 

Park Service 2006). The connection between the geology 

of the island and these cultural landscapes is described in 

the Features and Processes section.

Geologic Setting

Ebey’s Landing National Historical Reserve lies within 

the Puget Lowland physiographic province, a broad, 

low-lying region between the Cascade Range and the 

Olympic Mountains (Easterbrook 1994; Dragovich et al. 

2005). Similar to most of the Puget Lowland, Ebey’s 

Landing National Historical Reserve contains abundant 

glacial sediments and no bedrock exposures (fig. 4). 

Thick unconsolidated deposits cover bedrock that is 

possibly Miocene in age (23–5 million years ago) and lies 

about 350–790 m (1,150–2,600 ft) below the surface

(fig. 5). The oldest sediment exposed in the area is the 

185,000(?)–125,000-year-old Double Bluff Drift [map 

unit Qgd(d)], which crops out at beach level south of 

Ebey’s Landing.

Glacial and interglacial units on Whidbey Island record 

the advance and retreat of glaciers during the Pleistocene 

ice ages. The most recent glacial advances occurred 

approximately 18,000 and 14,000 years ago, during a 

period known as the Vashon Stade of the Fraser 

Glaciation (Burns 1985; Polenz et al. 2005; Washington 

State Department of Natural Resources 2010). A “stade” 

is a substage of a glacial stage. During the Vashon Stade 

glacial maximum, Whidbey Island was covered with 

about 1,250 m (4,100 ft) of ice. The Vashon Till [map unit 

Qgt(v)], a deposit of poorly sorted boulder-clay, was left 

when the glaciers melted.

Most of the upland areas of Whidbey Island and Camano 

Island, which lies between Whidbey Island and the 

mainland, are covered by Vashon Till. The till varies in 

thickness from less than one meter to approximately 53 

m (175 ft) and covers outwash sands [map unit Qga(v)] 

that were also deposited during the Vashon Stade. The 

till is overlain by glaciomarine drift gravels deposited 

about 13,500 years ago during the Everson Interstade 

(fig. 4). Glaciomarine drift is a general term for any rock 

material that was deposited in a marine environment by a 

glacier, a pro-glacial debris flow, or an ice berg.

Other features that record glacial processes at Ebey’s 

Landing National Historical Reserve include drumlins 

(elongate oval hills or ridges of compacted glacial till) 

and kettle ponds (fig. 6), which formed in steep-walled 

depressions exceeding 60 m (200ft) in depth that were 

left behind when large, soil-covered blocks of glacial ice 

melted. 

Although no tectonic faults have been mapped onshore, 

the reserve area is tectonically active. Tectonic land-level 

changes may occur due to movement along the 

northwest-trending Southern Whidbey Island fault, 

which lies 10 km (6 mi) southeast of Admiralty Head 

(Polenz et al. 2005). This fault has produced shallow 

crustal earthquakes in the Quaternary and is capable of 

generating large earthquakes with surface-wave 

magnitudes of 7 or greater. Approximately 2,800–3,200 

years ago, Crocket Lake was uplifted 1–2 m (3–7 ft) as a 

result of movement on the Southern Whidbey Island 

fault caused by a magnitude 6.5–7 earthquake (Kelsey et 

al. 2004).

A Holocene fault branching to the east from the 

Southern Whidbey Island fault may have produced the 

multiple north-dipping thrust faults that are exposed in 

pre-Vashon sediments south of Ebey’s Landing. The 

faults do not penetrate the Vashon deposits. In the 

northeastern corner of the reserve, a poorly defined, 

northwest-trending pre-Vashon-age fault has been 

mapped parallel to the Oak Harbor Fault, which lies 

north of the reserve (Dragovich et al. 2005; Polenz et al. 

2005).

North of the reserve, the Utsalady Point, Strawberry 

Point, and Devils Mountain faults comprise a westtrending, active, complex, transpressional deformation 

zone (Johnson et al. 2003; Dragovich et al. 2005; Polenz 

et al. 2005). The faults have uplifted Pleistocene strata in 

the Oak Harbor area relative to the Ebey’s Landing 

National Historical Reserve region. Trenching along the 

Utsalady Point fault unearthed evidence of possible 

postglacial fault movement between 1550 and 1850 C.E. 

(Johnson et al. 2003).

Cultural History

Skagit, Snohomish, Kikalos, and Clallam tribes inhabited 

central Whidbey Island as early as 1300 C.E., more than 

500 years before Euro-American settlers arrived. 

Abundant salmon, bottom fish, shellfish, berries, small 

game, deer, water fowl, and other natural resources 

encouraged the Skagit Indians to establish three 

permanent villages on the shores of Penn Cove at 

Snakelum Point, Long Point, and Monroe’s Landing. 

They practiced selective burning, transplanting, and 

mulching on the prairies for the cultivation of root crops 

such as bracken fern, camas, and nettles. Although more 

than 1,500 American Indians were living in the area in 

1790, the American Indian population around Coupeville 

had been reduced to a few small families by 1904.

In 1825, the Hudson Bay Company established Fort 

Vancouver on the Columbia River, which would serve as 
EBLA Geologic Resources Inventory Report 3

their headquarters for the Pacific region. Directors and 

senior officers of the Hudson Bay Company organized 

the Puget Sound Agricultural Company in 1840 to 

develop agricultural businesses and settlements in the 

region. Members of the Hudson Bay Company 

introduced the potato to Whidbey Island in the early 

1800s, which resulted in the transformation of the 

prairies into permanent agricultural lands. 

Captain George Vancouver named Whidbey Island in 

honor of his Lieutenant, Joseph Whidbey, who explored 

the island in 1792. Vancouver’s exploration of Puget 

Sound helped prepare the way for Euro-American 

settlers, although the Donation Land Law of 1850 was a 

more significant inducement. This law offered free land 

in Oregon Territory to any citizen who would homestead 

the land for four years. Within three years, droves of 

settlers had carved out irregularly- shaped claims in the 

fertile prairies of central Whidbey Island. This early 

settlement pattern can still be seen today on the reserve, 

where it is marked by fence lines, roads, and ridges.

Colonel Isaac Neff Ebey was among the first of the 

permanent settlers on the island. Samuel Crockett, 

Ebey’s friend, encouraged him leave his Missouri home 

and come to central Whidbey Island. Both Crockett and 

Ebey filed donation claims on central Whidbey in the 

spring of 1851. Ebey’s family soon joined him. The 

simple home of Jacob Ebey, Isaac’s father, and a 

blockhouse erected to defend his claim against American 

Indians, still stand today overlooking Ebey’s Prairie. 

Isaac became a leading figure in public affairs and 

established Ebey’s Landing, an improbable seaport on 

the windy Strait of Juan de Fuca where Ebey landed 

goods before carrying them up a ravine to his ferry 

house. Isaac’s contributions to the community were cut 

short, however, when Haida Indians decapitated him in 

1857 in revenge for the killing of one of their chieftains. 

Some farmers still cultivate the rich alluvial soil on 

donation land claims established by their families in the 

1850s, preserving a centuries-old historic land-use 

pattern. However, fertile farmland was not the only 

incentive to settle on Whidbey Island. The protective 

harbor of Penn Cove and the stands of tall timber valued 

for shipbuilding lured sea captains and merchants from 

New England to the island. These pioneers established 

donation claims along the shoreline. 

One colorful sea captain who made his home on central 

Whidbey Island was Thomas Coupe, who amazed his 

peers by sailing a full-rigged ship through treacherous 

Deception Pass on the northern end of the island. In 

1852, Coupe claimed 320 acres on the south shore of 

Penn Cove. The town of Coupeville was later built on his 

claim. 

Coupeville became a dominant seaport due to the early 

success of central Whidbey's farming and maritime trade. 

Traces of its lively past remain visible today in the many 

19th-century false-fronted commercial buildings on 

Front Street, the historic wharf and blockhouse, and the 

rich collection of Victorian residential architecture.

Whidbey Island became home to a thriving Chinese 

community between the 1880s and the 1920s. The 

community centered on Ebey’s Prairie farmlands, where 

the Chinese became indispensable farmhands for local 

white families. Like elsewhere in the American West, 

however, the Chinese were often treated as unwelcome 

outsiders. Fear that Chinese laborers would take jobs 

from white workers led to a series of political and social 

movements that targeted Chinese communities like the 

one on Whidbey Island.

Beginning in 1882, exclusion acts prevented most 

Chinese laborers from entering the country. Chinese 

merchants and laborers on Whidbey Island faced 

increasing hostility, intimidation, and violence from their 

neighbors. Anti-Chinese activities, spearheaded by the 

white business owners of Coupeville in the 1890s, and

virulent anti-Chinese editorials targeted Chinese 

residents of Ebey’s Prairie and other island communities. 

Unidentified vigilantes dynamited piles of harvested 

potatoes awaiting sale and shot the windows out of 

Chinese houses under the cover of night. 

Some Chinese took up arms to defend themselves, others 

enlisted the vocal support of white neighbors and 

employers, and some simply moved on, leaving Ebey’s 

Prairie permanently. By the late 1920s, the last aging 

Chinese residents of Ebey’s Prairie had moved off the 

island, returned to China, or died. Only scattered 

evidence remained of the 200 Chinese individuals who 

once made their home on Whidbey Island. Ah Soot, a 

Chinese emigrant who came to the United States in 1880 

and died in 1925, is buried in Sunnyside Cemetery and is 

the only known Chinese resident of Whidbey Island who 

chose not to make the final journey back to China for a 

traditional burial alongside his ancestors.

The military introduced another layer of island history 

with the construction of Fort Casey Military Reservation 

in the late 1890s. The fort was built on the bluff above 

Admiralty Head as part of a three-fort defense system 

designed to protect the entrance to Puget Sound. U.S. 

Army troops reported for duty in 1900, and 400 troops 

had been stationed at Fort Casey by 1910. Fort Casey 

became a social center for the surrounding community. 

The wood-framed officers’ quarters, gun escarpments, 

Admiralty Head Lighthouse, and other military remnants 

can still be seen at old Fort Casey. 

Fort Ebey, a remnant of the defensive build-up of World 

War II, stands near the northern boundary of the reserve. 

South of the fort, Navy pilots continue to use the 1943 

Coupeville Outlying Landing Field for aircraft carrier 

landing practice.

Authorized in 1978, Ebey’s Landing National Historical 

Reserve preserves and protects an unbroken historical 

record of Puget Sound exploration and settlement from 

the 19th century to the present. From the historical farms 

that are still under cultivation today to the Victorian 

seaport community of Coupeville, the reserve protects a 
4 NPS Geologic Resources Division

cultural landscape that connects the past and present spirits of the island.

Figure 1. Location map of Ebey’s Landing National Historical Reserve. National Park Service map available online: 

http://home.nps.gov/applications/hafe/hfc/carto-detail.cfm?Alpha=EBLA, accessed September 13, 2011.
EBLA Geologic Resources Inventory Report 5

Figure 2. Whidbey Island, the “C-shaped” island in the middle of the image lies approximately 48 km (30 mi) north of Seattle and forms the 

northern boundary of Puget Sound. The island is approximately 56 km (35 mi) long and 2.4–19 km (1.5–12 mi) wide. Map compiled by Jason 

Kenworthy (NPS Geologic Resources Division) from ESRI World Imagery basemap.
6 NPS Geologic Resources Division

Figure 3. Whidbey Island. Although the maximum elevation is only 150 m (500 ft), the western bluffs of Whidbey Island rise abruptly along 

the coastline and are susceptible to erosion and bluff retreat. Photograph courtesy Michael Polenz (Washington Department of Natural 

Resources).

Figure 4. This southwest-to-northeast geologic cross-section A–A’ from Polenz et al. (2005; see Geologic Map Overview Graphic) illustrates the 

thick sequence of glacial deposits and lack of bedrock in Ebey’s Landing National Historical Reserve. Vertical exaggeration is 10 times. Note 

the relatively flat topography formed by the deltaic and channel outwash deposits of the Partridge Gravel. This well-drained, flat topography 

became the preferred site for the Coupeville airport. The wells that are shown are from the Island County well database. TD is the total depth 

of the well. Map units are the same as those found on the Map Unit Properties Table and the enclosed GIS map. The location of the crosssection is also on the Geologic Map Overview Graphic. Cross section from Polenz et al. (2005).

Lithologic Units

Post-glacial Deposits

Qd Dune deposits Qb Beach deposits

Deposits of the Fraser Glaciation

Everson Interstade Vashon Stade

Qgom(ee) Glaciomarine drift, beach Qgt(v) Till

Qgdm(e) Glaciomarine drift, undivided

Qgom(e) Partridge Gravel

Qu Pleistocene deposits, undivided
EBLA Geologic Resources Inventory Report 7

Epoch

Age 

(thousands of 

years before 

present)

Stratigraphic Units

(map symbols) General description of units

Late 

Pleistocene -

Holocene

12.69–present

Postglacial deposits

Qf, Qml, Qb, Qd, Qp, Qm, Qmw, 

Qls, Qs

Marsh, peat, mass wasting, and dune 

(>9,000 years BP to recent) deposits.

Pleistocene

13.65–12.69

Glaciomarine sediments of 

Everson Interstade

Qgom(ee), Qmf(e), Qgdm(e), 

Qgdm(els), Qgos(e), Qgim(e)

Glaciomarine drift (gravel, sand, silt, clay); 

fan deposits; landslide deposits; icemarginal moraine deposits.

Partridge Gravel

Qgom(e), Qgog(e) Sand, gravel, sand-gravel mixtures.

~18 Vashon Drift

Qgt(v), Qgt(va), Qga(v)

Unsorted, unstratified till (loose gravel, 

sand, silt, and clay); outwash sand and 

gravel.

~60–18 Olympia Nonglacial Interval

Qc(o) Silt, clay, sand, interbeds of fine gravel

~80–60 Possession Drift

Qgd(p) Glaciomarine drift, till, outwash sand

~125–80 Whidbey Formation

Qc(w) Sand, silt, clay, peat layers

≥185–125 Double Bluff Drift

Qgd(d) Silt, clay, diamicton glaciomarine drift

Regional unconformity

(a break or gap in the stratigraphic succession of rock units) Pliocene

Miocene 5,330 Not exposed Bedrock at depth

Figure 5. General stratigraphic column for Ebey’s Landing National Historical Reserve. Ages (in thousands of years before 1950) are taken 

from Polenz et al. (2005). Detailed descriptions of each unit can be found in the Map Unit Properties Table.
8 NPS Geologic Resources Division

Figure 6. Lidar-based image of glacial features associated with Ebey’s Landing National Historical Reserve. Well-defined, north–south drumlins 

in the southeast record the southerly ice movement during the Vashon Stade. In the north, less-defined north–south drumlins are overprinted 

by southwest-trending drumlinization, which records southern ice movement followed by southwestern ice movement. The Coupeville 

moraine reflects a former ice margin. East and west of the moraine, outwash channels and kettles record the ice-proximal, marine-deltaic 

deposition of the Partridge Gravel. The smooth lowlands north and south of the Coupeville moraine represent the ancient sea floor. Vertical 

exaggeration is 6 times. Image courtesy Michael Polenz (Washington Department of Natural Resources). LIDAR data by David Finlayson 

(University of Washington).
EBLA Geologic Resources Inventory Report 9

Geologic Issues

The Geologic Resources Division held a Geologic Resources Inventory scoping session for 

Ebey’s Landing National Historical Reserve on September 10-12, 2002, to discuss 

geologic resources, address the status of geologic mapping, and assess resource 

management issues and needs. This section synthesizes the scoping results, in particular 

those issues that may require attention from resource managers. Contact the Geologic 

Resources Division for technical assistance.

Significant geologic issues facing resource managers at 

Ebey’s Landing National Historical Reserve were 

identified during the 2002 scoping meeting. The issues 

involve eroding bluffs and the protection of sustainable 

groundwater resources. Shoreline erosion causes bluff 

retreat and also negatively impacts archaeological 

resources on Whidbey Island (National Park Service 

2008). 

Other potential hazards include seismic (earthquake) 

and volcanic activity. The Southern Whidbey Island fault 

is tectonically active and has been the source of several 

historic, shallow crustal earthquakes. This fault has the 

potential to generate earthquakes with surface-wave 

magnitudes of 7 or greater (Polenz et al. 2005). In the 

past, volcanic activity from Glacier Peak in the Cascade 

Range has impacted the area of the reserve. In addition 

to these issues, global climate change may cause issues 

associated with relative sea level rise and the increased 

erosion of coastal bluffs.

Shoreline Erosion and Bluff Retreat

The shoreline along the western margin of Whidbey 

Island erodes at an approximate rate of 0.3 m (1 ft) per 

year (Keuler 1988; Shipman 2004). High waves during 

storms destroy the seaward edge of the beach face and 

batter the bluffs along the western shore (fig. 7). When 

the base of the bluffs is undercut, the bluffs collapse, 

generating the mass-wasting (map unit Qmw) and 

landslide deposits (map unit Ql) that appear on the 

park’s geologic map (see Geologic Map Data section). All 

of the shoreline bluffs are susceptible to episodic 

landsliding and resultant bluff retreat (fig. 8). Most slide 

deposits, however, are quickly removed by wave action 

(Polenz 2005). Global climate change may also increase 

bluff erosion (see below). Increased winter rainfall and 

relative sea level rise will negatively impact already 

unstable slopes (Karl et al. 2009).

Active erosion affects shell middens, the most common 

American Indian archaeological site on Whidbey Island. 

These sites are the remains of subsistence activities 

conducted a few hundred to a few thousand years ago. 

The majority of central Whidbey Island’s shell midden 

sites are found along marine shorelines, and most of 

these sites are actively eroding. Shoreline erosion may 

eventually destroy most of these middens (National Park 

Service 2008).

In Island County, approximately 50% of the shoreline 

has been designated as unstable (Shipman 2004; Klinger 

et al. 2007). Wieczorek and Snyder (2009) described 

various types of slope movements and triggering 

mechanisms for mass-wasting processes and suggested 

five significant properties, or vital signs, that could be 

used to monitor slope movements. These vital signs 

included: 1) type of landslide, 2) landslide triggers and 

causes, 3) geologic material components, 4) landslide 

movement, and 5) landslide hazards and risks. Although 

these vital signs are associated primarily with mass 

movement in bedrock terrain, they may be applicable to 

the monitoring of mass-wasting and landslide potential 

along the steep shoreline bluffs of Ebey’s Landing 

National Historical Reserve.

Bush and Young (2009) delineated vital signs that can be 

used to provide insight into the general state of a coastal 

ecosystem, changes in the system, and the vitality of the 

system. These vital signs included: 1) shoreline change, 2) 

coastal dune geomorphology, 3) coastal vegetation cover, 

4) topography/elevation, 5) composition of beach 

material, 6) wetland position/acreage, and 7) coastal 

wetland accretion. They also provided detailed 

monitoring techniques and recommendations for 

resource managers, including a description of the 

necessary expertise, personnel, and equipment, 

approximate cost, and labor intensity.

Reserve resource managers may consider implementing 

these various monitoring strategies in order to mitigate 

bluff erosion and its impact to archaeological sites.

Groundwater Resources

The unconsolidated sediments in Ebey’s Landing 

National Historical Reserve contain an aquifer with a 

finite water supply that begins at a depth slightly above 

sea level and extends to about 61 m (200 ft) below sea 

level (Klinger et al. 2007). This aquifer is referred to as 

the sea level aquifer, and it is the sole source of domestic 

and agricultural water for the area. Because it is the only 

aquifer on the island, the government of Island County 

requested and received from the U.S. Environmental 

Protection Agency the designation as a Sole Source 

Aquifer in 1982. The designation provides for a high level 

of regulatory protection and an additional review of any 

federally funded projects to ensure that there will be no 

degradation to the county’s aquifer system (National 

Park Service 2006).
10 NPS Geologic Resources Division

The groundwater system is recharged by precipitation, 

although most precipitation is lost to runoff, 

transpiration by plants, or evaporation. Less 

precipitation than might be expected falls on Whidbey 

Island because it lies in the rain shadow of the Olympic 

Mountains, which stand between the Pacific Coast and 

the island. Because of the rain shadow effect, an annual 

average of only 0.5 m (1.6 ft) of rain falls in the vicinity of 

Coupeville, in comparison with the 3.7 m (12 ft) of 

annual rainfall received by the west-facing valleys of 

Olympic National Park. 

Surface permeability also influences groundwater 

recharge. Glacial sediments containing abundant clay 

have low permeability and impede vertical groundwater 

flow to the aquifer.

The withdrawal of groundwater for domestic, 

agricultural, and commercial use exceeds the recharge of

the aquifer in the vicinity of Ebey’s Landing National 

Historical Reserve. As a result, saltwater has intruded 

into the freshwater aquifer in some areas. Saltwater 

contamination has been documented within the reserve 

in the areas of West Beach, Coupeville, Ebey’s Prairie, 

and outside the reserve at Admiral’s Cove (National Park 

Service 2006). Since the aquifer can remain salty for an 

extended period once contaminated, preventive 

management of the aquifer is more effective and efficient 

than remedial measures. 

Increased water demand as a result of population growth 

and accompanying development has the potential to 

negatively impact groundwater recharge areas and to 

increase groundwater contamination. Saltwater intrusion 

and the introduction of nitrates, pesticides, and other 

contaminants may negatively impact the sea level aquifer. 

In 2007, the Water Resources Division of the National 

Park Service recommended that the reserve develop 

measures “to protect and preserve the sea level aquifer 

under coastal development and climate change 

scenarios” (Klinger et al. 2007, p. 87). Additional 

information regarding these measures is beyond the 

scope of this report, but may be obtained by contacting 

the Water Resources Division of the National Park 

Service in Fort Collins, Colorado.

Seismic (Earthquake) Potential

Although no tectonic faults have been mapped on 

Whidbey Island, gravity, aeromagnetic, and well data 

have been used to infer a northwest-trending fault, called 

the Southern Whidbey Island fault, which may have 

moved since the Pleistocene Ice Age (Gower 1980). The 

fault crosses southern Whidbey Island near Lagoon 

Point, about 10 km (6 mi) southeast of Admiralty Head. It 

enters the Coupeville quadrangle about 3 km (2 mi) 

south of Admiralty Head and extends to the west of 

Point Partridge (Wagner and Wiley 1980). The Southern 

Whidbey Island fault has been characterized as a broad 

(6–11 km; 4–7 mi), long-lived, transpressional zone that 

trends northwest (310°), dips near-vertically to steeply 

north-northeast, and can be traced for over 69 km (43 

mi) (Johnson et al. 1996). Despite the absence of 

recognized fault strands, future earthquakes associated 

with this fault zone could produce surface rupture within 

the reserve area (Michael Polenz, Geologist, Washington 

Department of Natural Resources, written 

communication, March 2011).

The Southern Whidbey Island fault separates two major 

crustal blocks and has been the source of several historic 

shallow crustal earthquakes. It is capable of generating 

magnitude 7 or greater earthquakes (Johnson et al. 1996). 

Data from trenching investigations in 2005 record four to 

possibly eight postglacial earthquakes along the fault 

zone, making it one of the most active shallow crustal 

faults documented in the Puget Lowland (Polenz et al.

2005). The 1–2 m (3–7 ft) uplift of Crocket Lake that 

occurred 2,800–3,200 years ago has been attributed to a 

6.5–7 magnitude earthquake in the Southern Whidbey 

Island fault zone (Kelsey et al. 2004).

An upright log, possibly a Douglas fir, discovered in the 

intertidal zone at the northwestern end of Penn Cove 

provides evidence of previous tectonic subsidence 

(Polenz 2005). The log has a diameter of approximately 

0.40 m (1.3 ft) including the bark and is heavily bored by 

clams (fig. 9). Data from subsurface cores indicate a 

minimum subsidence of 1.4 m (4.5 ft). Preliminary data 

from historical records and radiocarbon dating suggest 

that the log was rapidly submerged by a tectonic event 

that occurred between 1740 and 1790 C.E. or between 

1810 and 1850 C.E. (Polenz 2005).

The Utsalady Point, Strawberry Point, and Devils 

Mountain fault zones have been mapped a few 

kilometers north of the reserve (Johnson et al. 2001; 

Dragovich et al. 2005). These three west-trending fault 

zones comprise a complex transpressional deformation 

zone that has uplifted Pleistocene strata in the Oak 

Harbor area relative to strata in the reserve.

Evidence from trenching in the Utsalady Point fault zone 

suggests postglacial fault movement between 1550 and 

1850 C.E. (Johnson et al. 2003). The submerged log 

excavated at the northwestern end of Penn Cove may 

have been tectonically lowered into the intertidal zone as 

a result of this tectonic activity. The deformation event 

may have tilted the strata north of Penn Cove slightly to 

the south.

Another Holocene fault may extend east from the 

Southern Whidbey Island fault to the shore south of 

Ebey’s Landing. In this area, multiple north-dipping 

thrusts are exposed in pre-Vashon sediments, but the 

faults do not appear to penetrate the Vashon deposits 

(Wagner and Wiley 1980). 

Other faults have been mapped and inferred north of the 

reserve. The southeastern end of a poorly defined, 

northwest-trending, possibly pre-Vashon-aged fault is 

inferred to pass through the northeastern corner of 

Ebey’s Landing National Historical Reserve, and another 

northwest-trending fault, the Oak Harbor Fault, has 
EBLA Geologic Resources Inventory Report 11

been mapped north of this probable pre-Vashon 

structure (Dragovich et al. 2005). 

The town of Coupeville is built on glaciomarine drift 

composed primarily of silt and clay [map unit Qgdm(e)]. 

Possible liquefaction features in Pleistocene deposits 

(map unit Qu) along the shoreline of Penn Cove, west of 

Long Point, suggest movement from previous 

earthquakes. Ground shaking from earthquakes may 

present a hazard to historical buildings which were not 

engineered to withstand earthquakes.

Seismographs record earthquakes and many of them 

automatically send their data to centralized locations for 

routine analysis. The U.S. Geological Survey maintains 

an earthquake website (http://earthquake.usgs.gov, 

accessed June 1, 2011) that contains historical and nearreal-time data, as well as links to regional information. 

The Pacific Northwest Seismic Network 

(http://www.pnsn.org/, accessed June 1, 2011) provides 

information on Pacific Northwest earthquake activity 

and hazards and operates seismographs in Washington 

and Oregon. These websites can provide up-to-date 

information on seismic activity affecting Whidbey Island 

and Ebey’s Landing National Historical Reserve.

Glacier Peak Eruptive Potential

Glacier Peak lies approximately 110 km (70 mi) northeast 

of Seattle. Although Glacier Peak is a relatively short 

(3,213 m; 10,541 ft) volcanic peak in the Cascade Range, 

since the retreat of the ice-age glaciers approximately 

15,000 years ago, it has produced more explosive 

eruptions with voluminous volcanic ash content than any 

other Washington volcano except Mount St. Helens 

(Waitt et al. 1995; U.S. Geological Survey 2008). Glacier 

Peak and Mount St. Helens are the only Washington 

volcanoes to produce large, explosive ash eruptions. 

At Blowers Bluff (fig. 10), the Whidbey Formation [map 

unit Qc(w)], which was deposited between 125,000 and 

80,000 years ago, contains pebbles from a lahar (volcanic 

mudflow) generated by the Glacier Peak volcano (Polenz 

2005; Polenz et al. 2005). The lahar flowed into the area 

currently demarcated by Ebey’s Landing National 

Historical Reserve because neither Skagit Bay nor the 

Saratoga Passage existed at the time (Polenz 2005).

Since the retreat of glacial ice, Glacier Peak has produced 

only two major eruptions: one between 13,100 and 

12,500 years ago and another between 6,300 and 5,900 

years ago. Smaller eruptions that produce small amounts 

of ash and lahars of limited areal extent occur more 

frequently than these larger eruptions. In the past 2,000 

years, Glacier Peak has generated at least seven smaller 

eruptions (U.S. Geological Survey 2008). 

Should another large eruption occur from Glacier Peak, 

lahars present the greatest danger to communities 

located near the volcano (Waitt et al. 1995; U.S. 

Geological Survey 2008). Today, Skagit Bay eliminates 

the potential lahar hazard to Ebey’s Landing National 

Historical Reserve. Airborne ash, the second greatest 

hazard from a large Glacier Peak eruption, might impact 

Whidbey Island, but most of the ash would be carried 

eastward by the prevailing wind (Waitt et al. 1995). 

Should Glacier Peak erupt, earthquakes would 

accompany the eruption, although the potential extent of 

ground shaking is difficult to determine. Although 

relatively minor, the potential for ground shaking and 

ash fall from large Glacier Peak eruptions exists for 

Ebey’s Landing National Historical Reserve.

The U.S. Geological Survey Cascades Volcano 

Observatory website (http://vulcan.wr.usgs.gov/, 

accessed June 1, 2011) contains detailed information on 

the volcanoes in the Cascade Range, including Glacier 

Peak. The website contains information on potential 

volcanic hazards and related publications, photographs, 

and current news releases. It also provides links to other 

relevant websites. 

Climate Change

The Puget Sound region is expected to experience a 

number of impacts in the next 50–100 years due to 

climate change. Sea-level in the Puget Sound basin may 

rise 33 cm (13 in) or more by 2100, depending on the rate 

of ice melt from Greenland and Antarctica and local 

vertical land movement caused by isostatic rebound and 

tectonic subduction (Klinger et al. 2007; Karl et al. 2009). 

The projected heavier winter rainfall in the Puget Sound 

region will combine with rising sea level to increase 

erosion along the exposed bluffs facing Admiralty Inlet. 

Bluff recession typically results from the removal of 

material from the base of the bluff by wave action, 

causing the subsequent collapse of the unstable bluff 

slope. Rising sea level, an increase in rainfall intensity 

and frequency, and a corresponding increase in storm 

surges will combine to increase bluff erosion and retreat, 

particularly along the western coast of Whidbey Island 

(Klinger et al. 2007). 

Rising sea level will also inundate low-lying coastal areas, 

including wetlands, and change the salinity of semienclosed bays, such as Penn Cove. Rising sea level may 

eliminate Perego’s, Grasser’s, and Kennedy’s lagoons. 

Severe winter storms may breach Keystone Spit and 

negatively impact roads, campgrounds, and other 

infrastructure. Salt water intrusion into the sea-level 

aquifer will increase (Canning 2002; Klinger et al. 2007). 

In the Pacific Northwest, warmer, wetter winters 

followed by warmer summers will reduce the flow of 

freshwater in summer and increase water flow in fall and 

winter. These changes will impact the rates of aquifer 

recharge, soil saturation, and seawater intrusion into the 

sea-level aquifer. Frequent water shortages can be 

expected in summer. Projections of population growth 

and residential and commercial development in the 

vicinity of Ebey’s Landing National Historical Reserve 

are needed to assess the potential magnitude of these 

impacts associated with climate change (Klinger et al. 

2007). 
12 NPS Geologic Resources Division

Other Issues

Tsunamis

Some areas within Ebey’s Landing National Historical 

Reserve may be vulnerable to inundation from tsunamis 

generated by earthquakes along the Cascadia Subduction 

Zone, which lies off the coast of Washington, Oregon, 

and northern California. Keystone Spit, Crockett Lake, 

and the Admiralty Bay shoreline could be inundated to 

levels of 0.5–2 m (1.6–6.6 ft). Kennedy’s Lagoon, Mueller 

Point, and Long Point in Penn Cove may be inundated to 

similar levels (Walsh et al. 2005).

Earthquakes generated along the Cascadia Subduction 

Zone occur, on average, about every 500 to 540 years 

(Atwater and Hemphill-Haley 1997; Walsh et al. 2005). 

The characteristic magnitude of earthquakes along the 

subduction zone is not known, but the last earthquake, 

which occurred in 1700, has been estimated to have been 

a Richter scale magnitude 9 earthquake (Satake et al. 

1996, 2003; Walsh et al. 2005). 

Elwha Dam Removal

The nation’s largest dam removal project began in 

September 2011 in the Elwha Valley on the Olympic 

Peninsula, west of Ebey’s Landing National Historical 

Reserve. The project will remove two dams on the Elwha 

River that were built in 1910 and 1926. The Elwha 

watershed is the largest watershed in Olympic National 

Park, and restoration will return the river to its natural 

free-flowing state. More than 113 km (70 mi) of river will 

be restored, benefitting all five species of Pacific salmon 

(National Park Service 2011). 

Removal of the dams will also release approximately

13 million m3 (460 million ft3) of sediment to downstream 

and nearshore areas. Most of the released sediment is 

expected to impact the northern shore of the Olympic 

Peninsula, but the entire eastern Strait of Juan de Fuca 

may be affected, including the western shore of Ebey’s 

Landing Historical Reserve. If the released sediment 

reaches the western shore, the most probable impact will 

be increased sediment along some shoreline areas 

(Klinger et al. 2007).

Updates on the dam removal project may be found on 

the Olympic National Park website 

(http://www.nps.gov/olym/naturescience/elwhaecosystem-restoration.htm, accessed June 3, 2011).

Oil and Fuel Spills

Ships carrying thousands of barrels of unrefined oil 

travel daily through Admiralty Inlet on their way to the 

major cargo ports of Seattle and Tacoma. Oil refineries 

near Anacortes and Bellingham also use shipping 

channels near Whidbey Island. In recent years, oil spills 

have occurred in Puget Sound, and future spills may 

impact the shoreline at Ebey’s Landing National 

Historical Reserve. 

The National Oceanic and Atmospheric Administration 

(NOAA) has developed a computer program, called 

GNOME (the General NOAA Oil Modeling 

Environment), that can be used to predict the path of an 

oil spill based on the wind, currents, and other forces 

(National Oceanic and Atmospheric Administration 

2005). The model is most useful when an actual spill has 

just occurred and can be accessed on the NOAA website 

(http://response.restoration.noaa.gov/software/gnome/

gnome.html, accessed June 7, 2011). 

In addition, the Washington State Department of 

Ecology (2003) has developed a geographic response 

plan for Admiralty Inlet. The purpose of the plan is to 

help those who are first on the scene of an oil spill to 

avoid the initial confusion that is common at any spill.
EBLA Geologic Resources Inventory Report 13

Figure 7. Steep shoreline bluffs at Ebey’s Landing National Historical Reserve are prone to erosion. Waves eroding the base of the bluffs 

cause mass wasting and landslides and then carry the material away from the shore. Photograph by Ashley Davis, courtesy Lys OppBeckman (Ebey’s Landing NHR).
14 NPS Geologic Resources Division

Figure 8. Schematic northwest—southeast geologic cross-section along the bluff from Ebey’s Landing to Fort Casey, Ebey’s Landing 

National Historical Reserve, illustrating abundant mass-wasting (Qmw) and landslide deposits (Qls) resulting from erosion. Erosion may 

also destroy cultural sites. The Double Bluff Drift [Qgd(d)] is the oldest unit exposed in the reserve. Black lines with arrows represent 

faults, with the arrows indicating the direction of movement. Vertical exaggeration is 10 times. The schematic begins and ends at the 

40-ft contour at the top of the bluff on the base map. Map units are the same as those found on the Map Unit Properties Table and the 

enclosed GIS map. The locations from which radiocarbon dates were obtained are reported on Table 1 of Polenz et al. (2005; Attachment 

1). The location of the cross-section is also indicated on the Geologic Map Overview Graphic. Cross-section from Polenz et al. (2005).

Lithologic Units

Post-glacial Deposits

Qmw Mass wasting deposits Qml Modified land

Qls Landslide deposits

Deposits of the Fraser Glaciation

Vashon Stade

Qgt(v) Till

Qga(vs) Sand-dominated advance outwash

Deposits of the Olympia Nonglacial Interval

Qc(o) Nonglacial deposits

Deposits of the Possession Glaciation

Qgd(p) Possession Drift

Deposits of the Double Bluff Glaciation

Qgd(d) Double Bluff Drift
EBLA Geologic Resources Inventory Report 15

Figure 9. Partially excavated log in the low intertidal zone at the northwestern end of Penn Cove. The log is in an upright position, and 

shells are attached to the bark. Photograph courtesy Michael Polenz (Washington Department of Natural Resources).
16 NPS Geologic Resources Division

Figure 10. Blowers Bluff. Located 1.6 km (1 mi) east along the shore from the parking lot at Penn Cove County Park, Blowers Bluff 

exposes units from the Whidbey Formation [oldest, map unit Qc(w)] to late Pleistocene sand (youngest, map unit Qs). Human in lower 

left corner for scale. The accompanying schematic illustrates the stratigraphic order of the units and includes unit symbols and lithology. 

The “lahar runout” deposit contains pebbles from an eruption of Glacier Peak. High-energy gravel deposits [map unit Qgog(e)] filled 

channels that truncated older units and eroded down to the Whidbey Formation. Sample numbers are from Table 2 in Polenz (2005) and 

Polenz et al. (2005; Attachment 1). Photograph and schematic courtesy Michael Polenz (Washington Department of Natural Resources).
EBLA Geologic Resources Inventory Report 17

Geologic Features and Processes

This section describes the most prominent and distinctive geologic features and processes 

in Ebey’s Landing National Historical Reserve.

The diverse physical and visual landscapes within the 

small geographic area of Ebey’s Landing National 

Historical Reserve are closely tied to the primary 

purpose of the reserve, which is to preserve and protect 

the cultural landscape. The reserve contains excellent 

examples of both glacial and post-glacial features and 

processes. Together with the distinctive climate, rain 

shadow location, soils, and maritime influence, these 

geologic features have helped shape the historical 

landscape of Whidbey Island and the unusual diversity of 

plant and animal species, communities, and habitats 

(National Park Service 2006). 

The Final General Management Plan and Environmental 

Impact Statement (National Park Service 2006) for 

Ebey’s Landing National Historical Reserve has divided 

the reserve into ten Landscape Character Areas based on 

the significant landforms and critical landscape 

components defined by NPS Landscape Architect Cathy 

Gilbert (Gilbert 1985). This section first outlines the 

glacial and post-glacial geologic features in the reserve 

and then associates each of these features with the 

appropriate Landscape Character Area.

Glacial Features and Processes

Glacial sediments dominate most of the Puget Lowland, 

including Ebey’s Landing National Historical Reserve. 

No bedrock exposures are present in the reserve. Rather, 

unconsolidated Pleistocene gravel, sand, silt, and clay 

deposits are exposed (fig. 4). 

Deposits of the Double Bluff Glaciation

Deposited approximately 185,000–125,000 years ago, the 

Double Bluff Drift [map unit Qdg(d)], is the oldest unit in 

the reserve and is exposed for only about 560 m (1,500 ft) 

of shoreline southeast of Ebey’s Landing (fig. 8). The unit 

consists of silt, clay, and diamicton deposited in a 

glaciomarine setting similar to the younger Vashon Till 

[map unit Qgt(v)]. A diamicton refers to poorly sorted, 

unconsolidated sediments with a wide variety of grain 

sizes enclosed within a sandy- to silty- or clayey- matrix.

Interglacial Deposits of the Whidbey Formation

In contrast to the glaciomarine sediments of the Double 

Bluff Drift, the sediments of the overlying Whidbey 

Formation [map unit Qc(w)] represent deposition during 

an interglacial period 125,000–80,000 years ago when the 

glaciers had melted and retreated to the north of 

Whidbey Island. More than 30 m (100 ft) of the Whidbey 

Formation forms the base of Blowers Bluff, which 

provides the most complete stratigraphic section within 

Ebey’s Landing National Historical Reserve (fig. 10). 

At Blowers Bluff, a vertical cliff face of up to 8 m (25 ft) of 

sand, silt, clay, and peat that were deposited in a 

floodplain form the base of the Whidbey Formation

(fig. 10). These sediments are overlain by gravelly, crossbedded channel sands that are interbedded with lahar 

deposits from Glacier Peak eruptions. The flat-lying 

deposits of sand, silt, peat, clay, and occasional gravel 

resemble the low-energy depositional setting of today’s 

lower Skagit River floodplain and channel, which is 

located approximately 8–32 km (5–20 mi) northeast of 

the reserve (Polenz 2005; Polenz et al 2005). Peat and 

organic matter appear to be scarce in the upper part of 

the Whidbey Formation, above the channel sand 

deposits; this scarcity may reflect a climate shift that

preceded renewed glaciation approximately 80,000 years 

ago (Polenz 2005).

Deposits of the Possession Glaciation

About 80,000–60,000 years ago, glaciers advanced again 

into the area. Glacial marine (glaciomarine) drift and 

underlying glacial till and outwash sand deposits of the 

Possession Drift [map unit Qgd(p)] were deposited in 

front of this glacial advance. The silt, clay, and diamicton 

of the glaciomarine drift are compact and commonly 

contain shells. The drift can be indistinguishable from 

the till, which is composed of ash-gray to white, compact, 

sandy diamicton. The outwash sand is medium- to finegrained (Polenz et al. 2005). 

Along Blowers Bluff, about 3 m (10 ft) of glaciomarine 

Possession Drift overlies the Whidbey Formation, but 

the unit thickens to the north (Polenz 2005). At West 

Beach and within 2.4 km (1.5 mi) southeast of Ebey’s 

Landing, the unit is predominantly sand (Polenz et al. 

2005). 

Sediments of the Possession Drift are similar to those of 

the Vashon Till [map unit Qgt(v)] and Everson 

glaciomarine drift [map unit Qgom(e)]. Consequently, 

the Possession Drift can only be identified if local field 

relations indicate that the deposits are older than the 

Vashon Till. Surficial drift deposits are assumed to be 

associated with the younger deposits of the Fraser 

Glaciation (Polenz 2005).

Deposits of the Olympia Nonglacial Interval

Olympia nonglacial deposits [map unit Qc(o)] overly the 

Possession Drift and are similar to those in the Whidbey 

Formation. In many locations, the presence of 

Possession Drift sediments provides the only way to 

distinguish the silt, sand, and occasional interbeds of fine 

gravel comprising the Olympia nonglacial deposits from 

those of the Whidbey Formation (Polenz 2005). 
18 NPS Geologic Resources Division

At Blowers Bluff, the Olympia nonglacial deposits form a 

4.6-m (15-ft)- thick section of homogeneous buff to light 

yellowish-brown silt (fig. 11). However, the interval can 

be as thick and lithologically diverse as the Whidbey 

Formation found at the base of the bluff (Polenz 2005).

The Olympia sediments at Blowers Bluff deserve a 

special note. The silt, known as West Beach silt, has been 

interpreted as a loess deposit (Polenz et al. 2005). Loess is 

wind-blown silt that is deposited near the margins of 

former or existing glaciers. Typically, compacted loess 

forms vertical bluffs, like those at Blowers Bluff. Eastern 

Washington contains widespread loess deposits, but with 

the exception of the West Beach silt, loess is surprisingly 

sparse in western Washington. The only recognized 

exposures of West Beach silt are located in the rain 

shadow area northeast of the Olympic Mountains. The 

paucity of loess in western Washington may be the result 

of the wet regional climate, but it is not clear whether the 

climate has caused a lack of deposition, lack of 

preservation, or both (Polenz 2005). Radiometric dates 

from overlying and underlying units constrain the age of 

the West Beach silt in the reserve area to between about 

37,000 and 27,000 radiocarbon years B.P. (before 

present, used to express radiocarbon years before 1950; 

Polenz 2005).

Habitat requirements for the freshwater clams and snails 

found in the Olympia nonglacial sediments south of 

Ebey’s Landing and along the north shore of Penn Cove 

favor freshwater, low-energy depositional environments 

similar to those evidenced in the Whidbey Formation. 

Dates obtained from shells and paleosols indicate that 

the Olympia nonglacial interval occurred approximately 

37,000–16,800 years B.P. (Polenz 2005).

Deposits of the Vashon Stade

The last major glacial advance into the region occurred 

approximately 18,000–14,000 years ago and is known as 

the Vashon Stade of the Fraser Glaciation (Washington 

State Department of Natural Resources 2010). Roughly 

1,200–1,300 m (3,900–4,300 ft) of ice blanketed Whidbey 

Island during this time. Sediments representing Vashon 

glacial deposits include outwash sand and gravel that was 

deposited in advance of the approaching ice [map unit 

Qga(vs)] and deposits of unsorted, boulder-clay layers 

referred to as Vashon Till [map unit Qgt(v)]. 

Although Vashon glacial deposits form the dominant 

landforms in many parts of the Puget Lowland, they are 

relatively sparse in Ebey’s Landing National Historical 

Reserve. Rather, Everson Interstade recessional deposits 

dominate the landscape in the reserve. At Blowers Bluff, 

for example, the outwash sand and gravel layer is about 

5.5 m (18 ft) thick, but it is truncated to the south and 

discontinuous to the north. Vashon Till is absent at 

Blowers Bluff, but the unit thickens to approximately 9 m 

(30 ft) farther north (Polenz 2005). However, the absence 

of Vashon glacial deposits at Blowers Bluff can be 

explained by the overlying unit and the processes 

responsible for its deposition.

On the south side of the Blowers Bluff exposure, a thick 

gravel unit has erased any evidence of Vashon glacial 

deposits and rests directly on the lower part of the 

Whidbey Formation. The gravel [map unit Qgog(e)] has 

also truncated all of the Vashon and pre-Vashon units 

that are exposed on the north side of Blowers Bluff. 

Along the Penn Cove shoreline, the high-energy gravel 

truncates at least 12 m (40 ft) of pre-Fraser units (fig. 10). 

The steeply- dipping, crudely to well-bedded gravel 

contains lenses of sand, silt, and clay, as well as boulders 

and clay rip-up clasts from the underlying units. The 

presence of boulders, rip-up clasts, and steeply- dipping 

beds, and the evidence of dynamic scouring of the 

underlying units, are indicators of a high-energy flow 

regime that eroded most of the Vashon glacial deposits as 

the glaciers receded to the north (Polenz 2005; Polenz et 

al. 2005).

South of Coupeville, low, smoothly rounded drumlins 

formed under the margin of the southward movement of 

ice during the Vashon Stade (fig. 6; Polenz et al. 2005). 

The long axes of these drumlins parallel this southward 

ice movement. Usually, a drumlin has a blunt nose in the 

direction of the ice approach and a gentler slope tapering 

in the other direction. The drumlins north of Coupeville 

have a similar north–south orientation that is 

overprinted by a southwest–trending alignment (fig. 6). 

This alignment may represent a reorientation of the ice 

flow to the southwest toward the end of the glaciation 

north of Coupeville.

Everson Interstade

Where contacts are exposed, high-energy gravel [map 

unit Qgog(e)] always stratigraphically underlies the 

Everson glaciomarine drift [map unit Qgdm(e)] and 

overlies the Vashon Till (Polenz 2005). A continuous 

sheet of gravel forms a gentle south-sloping topography 

north of Penn Cove, and the slope was formed by the 

erosion of older underlying units. Exposures at San de 

Fuca and in a gravel quarry 0.3 km (0.2 mi) south of the 

southwestern end of Penn Cove show the high-energy 

gravel unit grading into the Partridge Gravel [map unit 

Qgom(e); fig. 12]. The gradational contact between these 

two units suggests that the high-energy gravel is laterally 

equivalent to the Partridge Gravel and belongs to the 

Everson Interstade (Polenz 2005; Polenz et al. 2005). 

The voluminous Partridge Gravel that forms the elevated 

terraces on either side of Ebey’s Prairie probably came 

from the high-energy gravel at Blowers Bluff. The 

northern edge of the Partridge Gravel is known to have 

been in contact with the glacier. Consequently, the highenergy outwash deposit along the northern shore of 

Penn Cove likely represents a mostly or entirely 

subglacial flow deposit (Polenz 2005; Polenz et al. 2005).

The relatively thick Partridge Gravel forms the elevated 

landscape of Smith Prairie and the gentle topography 

west of Ebey’s Prairie, south of Penn Cove. The Partridge 

Gravel represents a kame-delta complex in which 

outwash sand and gravel were deposited in a marine 

environment adjacent to the receding ice margin (Polenz 
EBLA Geologic Resources Inventory Report 19

2005). Horizontal, sand-dominated bottom beds 

(bottom-set beds) reflect deposition on the sea floor. 

Low-energy gravity flow produced low-angle crossbedding, flame structures, and other soft sediment 

deformation features in these bottom beds (fig. 13). 

Sloping beds of gravel and sand that formed at the front 

of an advancing delta overlie the bottom beds. These 

beds are known as foreset beds (fig. 14). As the delta built 

seaward, distributary channels formed on the top of the 

delta (top-set beds), transporting meltwater and outwash 

sand and gravel to the delta front (fig. 14; Polenz 2005: 

Polenz et al. 2005). 

On average, the Partridge Gravel is 30–76 m- (100–250 ft) 

thick and contains approximately 0.8–2.5 km3 (0.2–0.6 

mi3) of sand and gravel (Polenz et al. 2005). The coastal 

cliffs at Cedar Hollow expose 64 m (210 ft) of Partridge 

Gravel and 1.5–12 m (5–40 ft) of overlying post-glacial, 

wind-deposited, Holocene sand (map unit Qd; fig. 15). 

Foreset beds in the middle of the cliff grade down into 

bottom-set sand beds at the cliff base. The bottom-set 

beds contain occasional lenses of sand-sized fragments 

of volcanic rock, coal, peat, charred wood, and minor 

charcoal that were re-worked from older Whidbey 

Formation and Olympia nonglacial sediments (Polenz 

2005). Top-set beds cap the kame-delta sequence.

Marine clams found in the top-set beds of the Partridge 

Gravel helped to prove that the unit was a marine 

sequence rather than a lake deposit, as previously 

interpreted (Carlstad 1992; Polenz 2005). The clams 

could also provide constraining radiocarbon dates for 

the break-up of the Vashon glacial ice and the 

subsequent incursion of marine water into the region 

that initiated the Everson Interstade (see the Geologic 

History section). 

Cedar Hollow is one of many bowl-shaped depressions 

formed in Ebey’s Landing National Historical Reserve 

(fig. 6). Called kettles because of their shape, these 

depressions formed when stagnant blocks of ice that had 

been buried by Partridge Gravel melted, allowing the 

overlying sand and gravel to collapse into the resulting 

subterranean void. On the margins of the closed 

depression, small shear planes formed in the Partridge 

Gravel (fig. 16). The collapse caused the top-set beds, 

which are normally horizontal, to curve down into the 

depression. 

Many kettles of diverse sizes formed north and east of 

Cedar Hollow and some formed east of Coupeville

(fig. 6). All of these kettles formed near the Everson 

Interstade ice margin that was located just south of Penn 

Cove, along the Coupeville moraine. Their spatial 

clustering confirms the deposition of the Partridge 

Gravel near the margin of the melting ice sheet (Polenz 

2005). 

At the time of the Partridge Gravel deposit 

approximately 14,000 years ago, a temporary ice margin 

existed at the northern end of Ebey’s Prairie. The 

recognition of this ice margin is based on the 150–240 m-

(500–800 ft)-wide, east–west trending, gentle ridge that 

extends across Coupeville. Known as the Coupeville 

moraine [map unit Qgim(e)], this ridge aligns with the 

northern limit of the Partridge Gravel, suggesting that it 

formed at the margin of the ice sheet. The blanket of 

glaciomarine drift that covers Ebey’s Prairie may thicken 

to the south, which would also indicate that the moraine 

represents a temporary ice margin (Polenz 2005).

The moraine consists of cobbly to boulder, angular to 

rounded gravel in a loose, powdery matrix of finergrained sediments (fig. 17). More erratic boulders litter 

the moraine’s surface than anywhere else in Ebey’s 

Landing National Historical Reserve (Polenz 2005; 

Polenz et al. 2005).

Both the high-energy gravel and Partridge Gravel grade 

upward into glaciomarine drift [map unit Qgdm(e)] that 

was deposited on the sea floor during the Everson 

Interstade (fig. 12). Thick glaciomarine drift covers 

Ebey’s Prairie and is further evidence for a late glacial 

incursion of marine water into the region (Polenz et al. 

2005). At the glacial maximum of the Vashon Stade, 

approximately 900–1,200 m (3,000–4,000 ft) of ice 

depressed the crust in the Puget Lowland (Polenz 2005). 

The ice prevented seawater from flooding the area, but 

once the ice melted, seawater filled Ebey’s Prairie until 

the crust rebounded in response to the removal of its 

weight. The gentle mounds present on the surface of 

Ebey’s Prairie, including the three hills southeast of 

Ebey’s Landing, are drumlins that have had their original 

topographic profile subdued by the blanket of 

glaciomarine drift (Polenz 2005).

Some of the thickest deposits of glaciomarine drift are 

found at Ebey’s Landing. The cliff consists of at least 12 

m (40 ft) of glaciomarine drift overlain by 1.2–3 m (4–10 

ft) of fine sand (map unit Qd). The sand, silt, and clay of 

the glaciomarine drift contain marine shells and a few 

dropstones (oversized rocks transported out to sea on 

floating pieces of ice). About 0.2 m (0.5 ft) of pebbly 

gravel forms a thin layer at the top of the glaciomarine 

drift. This layer has been interpreted as an emergent 

deposit, such as a beach deposit, that marks the end of 

marine inundation into the area (Domack 1983; Polenz 

2005).

At Blowers Bluff, glaciomarine drift overlies high-energy 

gravel (fig. 10). As at Ebey’s Landing, the unit contains 

boulders and clumps of till that were rafted into position 

on icebergs and then dropped to the bottom of the sea 

when the ice melted. 

When the ice melted and the glaciers retreated 

approximately 13,000 years ago, the region remained 

depressed for a brief (in geologic time) period. Sea level 

rose and glaciomarine drift was deposited across the 

reserve area. However, once the thick ice sheet was 

removed, the land rebounded and Whidbey Island 

emerged above sea level. The landforms and deposits 

that today occupy central Whidbey Island have changed 

little in the last 10,000 years.
20 NPS Geologic Resources Division

Post-glacial Features and Processes

Numerous post-glacial features have been mapped in 

Ebey’s Landing National Historical Reserve, including 

beach and dune deposits, sheet sands, peat, marsh and 

lagoon deposits, mass-wasting and landslide deposits, 

and paleosols (ancient soils; Polenz et al. 2005). About 

0.2 m (0.5 ft) to 1.2 m (4 ft) of late Pleistocene fine sand

and silt (map unit Qs) blankets the reserve area and 

typically forms topsoil. The unit, however, has been 

mapped only where it appears to exceed 1.5 m (5 ft) in 

thickness (Polenz et al. 2005). At Blowers Bluff, 2.4–3 m 

(8–10 ft) of this post-glacial sand caps the stratigraphic 

sequence (fig. 10). 

The sand sheet appears to have a mixed sedimentological 

origin. In places, such as Cedar Hollow, the wellrounded, well-sorted, well-drained sand appears to be 

eolian in origin. However, the angular grain morphology 

of the sand sheet about 0.5 km (0.3 mi) north of the 

Libby Road beach suggests a glaciomarine, diamicton 

source. Regardless of origin, however, this sand sheet has 

a greater degree of soil development and stratigraphically 

underlies the modern dunes (map unit Qd; Polenz 2005). 

At Cedar Hollow, the late Pleistocene sand sheet is 

capped by a paleosol that lies below a fossil assemblage 

dated to approximately 10,000 years ago (see the 

Paleontological Resources section). This paleosol is 

absent in most places, where the sand sheet forms the 

uppermost geologic deposit and is part of the modern 

surface. However, the thick Holocene dunes separate the 

paleosol from the modern surface at Cedar Hollow

(fig. 18; Polenz 2005). 

The paleosol separating the late Pleistocene sand sheet 

from modern dune sand is the most strongly developed 

paleosol in the Cedar Hollow section. Significantly, such 

a strong soil profile requires sufficient time to develop 

without input from wind-blown sand. Details about this 

time period are scarce, but the soil developed either 

during a period of environmental stability or in a 

paleoenvironment that was more conducive to soil 

development than the previous and subsequent 

environments (Carlstad 1992; Polenz 2005). Further 

study of the paleosol may provide insight into the 

evolution of the Puget Lowland climate and ecosystem 

since the last glaciation (Polenz 2005).

Hills and ridges of wind-blown sand dunes (map unit 

Qd) have formed on upland surfaces and in kettle 

sidewalls along or near west-facing bluffs north of Ebey’s 

Landing. The sand is moderately to well sorted, and dune 

morphology suggests that its depositional environment 

lacked the forests that cover most of these dunes today. 

Limited soil development on the dunes and their 

location within 0.8 km (0.5 mi) of the present day 

shoreline bluffs, however, suggest that deposition may 

also be recent and ongoing (Polenz et al. 2005). The 

coastal cliffs at Cedar Hollow expose 1.5–12 m (5–40 ft) 

of post-glacial, wind-deposited sand (fig. 15). The sand 

has yielded numerous mammal and bird bone fossils (see 

the Paleontological Resources section).

Peat deposits (map unit Qp) include organic-rich mineral 

sediments deposited in closed depressions. The peat, 

muck, silt, and clay associated with wetlands are the 

freshwater equivalents of the organic-rich marsh 

sediments (map unit Qm) deposited in saltwater or 

brackish marsh (estuarine or lagoonal) environments. 

Peat deposits may grade downward into marsh deposits.

Grasser’s Lagoon is a 7.7-ha (19-ac) salt marsh that is 

tidally inundated twice daily. The relationship between 

geology and ecosystem management is illustrated by the 

rocky sandspit that forms the outer boundary of the 

lagoon. The spit supports significant numbers of shorebirds including high concentrations of turnstones, 

surfbirds, and rock sandpipers.

A 30–45-m- (100–150-ft-) wide beach consisting of sand, 

gravel, and cobbles separates Perego’s Lagoon from the 

inlet. This coastal lagoon is located south of Point 

Partridge and north of Ebey’s Landing. Longshore 

currents deposit eroded upland sediments along this 

stretch of coast, which also is impacted by moderate 

wave action. The cliff face bordering the lake rises 

approximately 73 m (240 ft) from the water’s edge.

Crockett Lake, the largest inland water feature on the 

reserve, was originally a salt marsh opening to Admiralty 

Bay (National Park Service 2006). The lake has been 

severely altered by early settlers and local residents. Tidal 

gates were installed in 1948, and lake levels have been 

manipulated since then, diminishing the productivity and 

scenic value of Crockett Lake. The tidal gates are still in 

place but in disrepair. It is unclear to what extent the 

gates continue to inhibit natural water flow, sediment 

flux, and fish passage.

Beach deposits (map unit Qb) contain primarily sand and 

cobbles but may include boulders, silt, pebbles, and clay. 

The deposits consist of well-sorted mixtures of sediment 

derived locally from shoreline bluffs, underlying 

materials, and sediment carried in by longshore drift. 

Mass-wasting (map unit Qmw) and landslide deposits 

(map unit Qls) are generally unsorted and are located at 

the base of unstable, or potentially unstable, slopes

(fig. 8). Many of these deposits are too small to map at a 

1:24,000 scale, but all shoreline bluffs in the reserve are 

subject to episodic landsliding. Most slide deposits are 

removed by beach wave action (Polenz et al. 2005).

Paleontological Resources

Pleistocene and Holocene fossils have been discovered 

in Ebey’s Landing National Historical Reserve and offer 

opportunities for education, interpretation, and future 

scientific research in the park (Fay et al. 2009). In 2004, 

Pleistocene-aged Olympia nonglacial deposits [map unit 

Qc(o)] yielded a mastodon (proboscidean) tusk (fig. 19; 

Michael Polenz, Geologist, Washington Department of 

Natural Resources, written communication, March 

2011). When discovered, the tusk was quite weathered 

and has since been destroyed by erosion. 
EBLA Geologic Resources Inventory Report 21

Radiocarbon ages from freshwater mollusks collected 

from this unit range from approximately 11,850 to 13,230 

years B.P. (Polenz et al. 2005). Pollen collected from the 

Olympia nonglacial deposits in the Puget Lowland 

indicate that the cold, unstable climate dominating the 

region more than 48,000 years ago changed to a cool, 

moist climate approximately 33,000 years ago. At the end 

of the nonglacial interval and the beginning of Fraser 

Glaciation, cooler, dryer conditions prevailed (Hebda et 

al. 2007). Mammoth teeth, diatomites, pine cones, 

needles, branches, leaf prints, and in-situ tree roots 

discovered in these Olympia beds represent a diverse 

paleoecosystem during this time (Troost 2002).

Pleistocene glaciomarine drift from the Everson 

Interstade [map unit Qgdm(e)] contains marine shells. 

One of these shells, collected north of the reserve, 

recorded a radiocarbon age of 13,650 years B.P. (Polenz 

et al. 2005).

Pleistocene and Holocene post-glacial deposits have 

yielded a variety of animal and plant fossils (Fay et al. 

2009). The upright tree trunk (fig. 9) discovered in the 

estuary at the northwestern end of Penn Cove provided 

evidence for tectonic subsidence prior to 1850 C.E. 

(Polenz 2005). 

A concentrated bed of disarticulated skeletal remains 

from a variety of taxa was discovered in dune sands (map 

unit Qd) (fig. 20). The fossil land snails, birds, and 

mammals from this site have provided significant clues 

about the paleoenvironment of the area about 10,000 

years ago (Mustoe and Carlstadt 1995; Polenz 2005; Fay 

et al. 2009). This site in Ebey’s Landing National 

Historical Reserve contains the only known record of 

early Holocene, terrestrial animals in the Pacific 

Northwest, and documents the transition from late 

Pleistocene to more modern Holocene fauna (Mustoe et 

al. 2005; Fay et al. 2009). 

Other geologic units in Ebey’s Landing National 

Historical Reserve also may contain fossils. The Double 

Bluff Drift [map unit Qgd(d)], for example, was 

deposited at a time when large animals flourished in the 

region. Although no fossils have been discovered in the 

Whidbey Formation [map unit Qc(w)] within Ebey’s 

Landing National Historical Reserve, mammoth tusks, 

teeth, and bones are documented from the unit’s type 

section, located 25 km (15 mi) southeast of the reserve at 

West Useless Bay, Whidbey Island (Easterbrook et al. 

1967, 2003).

The Possession Drift [map unit Qgd(p)] contains shells, 

but their variety, quality, and distribution have not been 

described (Polenz et al. 2005; Fay et al. 2009). In British 

Columbia, outwash deposits of the Vashon Stade of the 

Fraser Glaciation contain mammoth remains, but no 

fossils have been found in this unit [map units Qga(v), 

Qga(vs)]within Ebey’s Landing National Historical 

Reserve (Fay et al. 2009).

A more detailed summary of the paleontological 

resources of Ebey’s Landing National Historical Reserve, 

as well as recommendations for paleontological resource 

management, may be found in Fay et al. (2009).

Landscape Character Areas

Table 1 summarizes some of the geological features 

associated with the Landscape Character Areas defined 

by Gilbert (1985).

These landscape areas connect the geology with the 

reserve’s cultural history. Similar to today’s farmers, for 

example, American Indians in the past grew crops on the 

relatively flat topography and rich soil of Ebey’s Prairie. 

Deposition of the clay-rich glaciomarine sediments [map 

unit Qgdm(e)] subdued the topography, retained 

moisture, and provided the parent material for soil 

development. 

The Partridge Gravel [map unit Qgom(e)] rendered 

Smith Prairie an attractive site for the Coupeville airport. 

The thick deposits of outwash channel sand and gravel 

are responsible for the well-drained, elevated, and flat 

landscape of Smith Prairie.

Penn Cove also originated through geologic processes. 

Swift-flowing rivers from pressurized subglacial 

meltwater carved a trough into the sediments between 

Coupeville and the uplands to the north, and this trough 

became Penn Cove (Michael Polenz, Geologist, 

Washington Department of Natural Resources, written 

communication, March 2011). The cove offers an ideal 

site for the cultivation of mussels and provides a 

naturally sheltered harbor for the town.
22 NPS Geologic Resources Division

Figure 11. The Olympia nonglacial interval exposed at the top of Blowers Bluff consists of about 4.6 m (15 ft) of homogeneous West Beach silt

(part of geologic map unit Qc(o). A pebbly paleosol (ancient soil layer; arrow) lies at the base of the silt. The gravelly Possession Drift, which 

includes some erratic boulders, forms the cliff beneath the paleosol and West Beach silt. Photograph courtesy Michael Polenz (Washington 

Department of Natural Resources).
EBLA Geologic Resources Inventory Report 23

Figure 12. Relationship between high-energy gravel [map unit Qgog(e)], Partridge Gravel [map unit Qgom(e)], and glaciomarine drift [map 

unit Qgdm(e)]. In this gravel quarry, located 0.3 km (0.2 mi) south of the southwestern end of Penn Cover, the large-scale channel crossbedding in the Partridge Gravel overlies the high-energy, glacial gravel that is exposed at Blowers Bluff and at the northern to western 

periphery of Penn Cove. The arrows indicate the base of two of these channels with a younger channel truncating an older channel. Crossbeds form as sediment (in this case, gravel) is deposited parallel to the channel boundaries. In this quarry, the high-energy gravel is covered 

by debris at the base of the Partridge Gravel. Large silt boulders in the gravel become increasingly common in the lower levels of the unit. 

Glaciomarine drift covers the Partridge Gravel. Where the Partridge Gravel is missing, glaciomarine drift overlies the high-energy gravel. 

Photograph courtesy Michael Polenz (Washington Department of Natural Resources).

Figure 13. Sedimentary features in the bottom-set beds of Partridge Gravel. Left: Low-energy currents formed wavy cross-beds in fine sand to 

silt deposited on the sea floor. These beds are now exposed at beach level along shoreline bluffs 0.8 km (0.5 mi) northeast of the Ebey’s 

Landing beach access parking lot. Right: Flame structures (features that resemble flames) formed in more proximal, coarser bottom-set sand 

beds of the Partridge Gravel. This exposure is also at beach level, and is located approximately 2.4 km (1.5 mi) northwest of the exposure 

depicted in the left panel. Photographs courtesy Michael Polenz (Washington Department of Natural Resources).

Glaciomarine drift Partridge Gravel

High-energy gravel
24 NPS Geologic Resources Division

Figure 14. Kame-delta top-set and foreset sand and gravel beds in the Partridge Gravel. The top-set beds are horizontal and overlie the 

gently-dipping foreset beds. Channel sand and gravel deposited in the top-set beds represent shallower depositional environments than do 

the foreset beds, which formed at the front of a delta. As the delta built seaward, the marine environment became more shallow and top-set 

beds prograded over foreset beds. View is to the southeast of the southern quarry wall at Smith Prairie, southeast of Coupeville. The slope of 

the foreset beds records a southwesterly paleoflow during the deposition of the Partridge Gravel at Smith Prairie. Photograph courtesy 

Michael Polenz (Washington Department of Natural Resources).
EBLA Geologic Resources Inventory Report 25

Figure 15. Northwest-trending shoreline at Cedar Hollow showing the bottom-set, foreset, and top-set beds of the Partridge Gravel [map unit 

Qgom(e)] and younger, eolian sand (map unit Qd) that blew into the depression to cover the Partridge Gravel. A paleosol formed on the 

surface of the Partridge Gravel prior to the deposition of the wind-blown sand. The upper image is the same as the lower image with 

explanatory schematic. View is to the northeast. Photograph courtesy of the Washington State Department of Ecology and extracted from 

Polenz (2005). Annotation by Trista Thornberry-Ehrlich after Polenz (2005).
26 NPS Geologic Resources Division

Figure 16. Shear planes in the Partridge Gravel. These features document the deformation of Partridge Gravel strata during the formation of 

Cedar Hollow. View is to the northeast. The arrow points to one of the northwest-dipping shear planes. Hammer for scale. Photograph 

courtesy Michael Polenz (Washington Department of Natural Resources).

Figure 17. Coupeville moraine exposed in a road cut along Broadway Street in Coupeville. The variety of clast sizes indicates that the unit is 

poorly sorted. The clasts range from angular (suggesting that they did not travel far from their origin) to well-rounded spheroids (suggesting 

the rounding of their edges during transport from their place of origin, usually implying a considerable transport distance). The unit also lacks 

sedimentary structures, such as cross-bedding or graded bedding. Hammer for scale. Photograph courtesy (Michael Polenz, Washington 

Department of Natural Resources).
EBLA Geologic Resources Inventory Report 27

Figure 18. Paleosol beneath the Holocene dune sand (map unit Qd) in Cedar Hollow. This paleosol (red-brown layer) is more strongly 

developed than any other paleosol in the overlying sand. Hammer for scale. Photograph courtesy Michael Polenz (Washington Department of 

Natural Resources).

Figure 19. Mastodon tusk. In 2004, a poorly preserved portion of a mastodon tusk (above the hammer head) was exposed in Olympia 

nonglacial deposits [Qc(o)] along the cliff between Ebey’s Landing and Admiralty Head. The fossil has since been removed by erosion. 

Photograph courtesy Michael Polenz (Washington Department of Natural Resources).
28 NPS Geologic Resources Division

Figure 20. Fossil fragments from dune sand (Qd), Ebey’s Landing National Historical Reserve. Left: Fossil fragments in the dune sand. Center:

Close-up of one rodent fossil exposure. Right: Some of the microtine rodent (vole) bone and tooth remains that have been radiometrically 

dated to 9,420 to 9,130 years of age (Polenz 2005). Photographs courtesy Michael Polenz (Washington Department of Natural Resources).

Table 1. Landscape Character Areas and Geologic Features.

Landscape Character Area Physical Description Geologic Features

San de Fuca Uplands Gently rolling hills that begin at the 

shoreline of Penn Cove and slope onto 

agricultural land.

Gently rolling hills of Vashon Till.

Penn Cove Nearshore and shoreline habitats in 

mudflat tidelands, high sandy bluffs, 

beaches, and eelgrass beds.

Beaches; mudflats; high, unstable 

sandy bluffs.

West Coastal Strip A 13-km (8-mi) strip of narrow sand 

and rocky beaches forming the western 

boundary of the reserve adjacent to 

Admiralty Inlet and the Strait of Juan de 

Fuca.

Narrow sand and rocky beaches; 

steep, unstable bluffs; ravines.

Kettle and Pratt Woodlands 

(West Woodlands)

Dense forests with kettles (glacial 

features) and trails that connect to Fort 

Ebey State Park.

Kettles up to 61 m (200 ft) deep; Lake 

Pondilla.

Coupeville The commercial center of the reserve 

and Washington State’s second oldest 

town.

Built mainly on glaciomarine drift (clay 

and silt).

Ebey’s Prairie The largest natural prairie on Whidbey 

Island, located in the central portion of 

the reserve.

Blanket of glaciomarine sediments 

have smoothed out the underlying, 

gently rolling hills of Vashon Till.

Fort Casey Uplands Gently rolling hills bearing forest, fields, 

and residential areas.

Gently rolling hills of Vashon Till.

Crockett Prairie Natural, open prairie adjacent to 

Crockett Lake, Keystone Spit, and 

Admiralty Bay.

Crockett Lake and prairie floored by 

glaciomarine drift.

Parker and Patmore 

Woodlands

Densely wooded second- and thirdgrowth Douglas fir forest located along 

a ridge in the eastern portion of the 

reserve.

Ridge of Partridge Gravel.

Smith Prairie A 240-ha (600-ac) natural prairie 

surrounded by Douglas fir forest.

Prairie underlain by Partridge Gravel.

Compiled from Gilbert (1985).
EBLA Geologic Resources Inventory Report 29

Geologic History

This section describes the rocks and unconsolidated deposits that appear on the digital 

geologic map of Ebey’s Landing National Historical Reserve, the environment in which 

those units were deposited, and the timing of geologic events that formed the present 

landscape.

Whidbey Island, nearby islands, and peninsulas are 

relatively young, Quaternary geomorphic features that 

emerged from the Salish Sea (the marine equivalent of 

the Puget Lowland) after the most recent ice age glacial 

retreat (fig. 21). The metamorphic, structural, and 

depositional history of the buried bedrock core of these 

islands, however, is exceptionally complex, and its origin 

remains a subject of debate (Michael Polenz, Geologist, 

Washington Department of Natural Resources, written 

communication, March 2011). Pre-Devonian and 

Devonian (416–359 million years ago) limestone, argillite, 

black shale, siltstone, and andesitic tuff are the oldest 

rocks in the islands, but these rocks, like the overlying 

Pennsylvanian and Permian submarine volcanic rocks, 

originally formed in paleo-environments that were far 

removed from the western margin of North America. 

During the Jurassic (200–145 million years ago), islands 

and oceanic material of a foreign terrane known as 

Wrangellia began to be accreted to the North American 

continent (fig. 22). Significant accretion continued 

during the Late Cretaceous (100–66 million years ago), 

but the relationship between these accreted terrains and 

Whidbey Island is not well understood.

While these older rocks form the foundation beneath the 

San Juan Islands, the present landforms and island 

geometry are the result of Pleistocene glaciers. During 

the late Pleistocene Fraser and earlier glaciations, the 

Cordilleran Ice Sheet extended from the mountains of 

coastal southern and southeastern Alaska, along the 

Coast Mountains of British Columbia, and into northern 

Washington and northwestern Montana (fig. 23). This 

ice sheet was the smaller of two great continental ice 

sheets that covered North America during the 

Quaternary. At times, the Cordilleran Ice Sheet likely 

coalesced with the western margin of the larger 

Laurentide Ice Sheet to form a continuous ice sheet over 

4,000 km (2,500 mi) wide (Booth et al. 2004).

The oldest Pleistocene sediments exposed on Whidbey 

Island, those of the Double Bluff Drift [map unit 

Qgd(d)], are found at beach level south of Ebey’s 

Landing and were deposited approximately 185,000–

125,000 years B.P. (fig. 8). The Double Bluff silt, clay, and 

diamicton were deposited in a marine environment that 

formed in front of an advancing ice sheet (Polenz et al. 

2005). Older Pleistocene sediments may be exposed 

elsewhere on the island, but their presence and age have 

not yet been documented (Michael Polenz, Geologist, 

Washington Department of Natural Resources, written 

communication, March 2011).

The Whidbey Formation represents a warm, interglacial 

period that existed from about 125,000–80,000 years B.P. 

(Heusser and Heusser 1981; Polenz et al. 2005). Whidbey 

sediments were deposited in low-energy floodplains and 

deltas, such as the floodplain associated with the 

ancestral Skagit River. During the deposition of the 

Whidbey Formation, the ancestral Skagit (or possibly 

Stillaguamish) River flowed into the present Whidbey 

Island, suggesting that Skagit Bay did not exist and even 

the Saratoga Passage may have been absent (Polenz 

2005). 

Glaciers returned to the area approximately 80,000 years 

B.P. and remained until 60,000 years B.P. Streams flowing 

from the advancing glaciers deposited outwash sand, 

which was subsequently covered by the glacial till and 

glaciomarine clay and silt of the Possession Drift [map 

unit Qgd(p)]. 

In another interglacial period from 60,000–20,000 years 

B.P. the silt, clay, sand, and gravel of the Olympia 

nonglacial interval [map unit Qc(o)] were deposited in 

the Puget Lowland. These sediments are similar to those 

of the Whidbey Formation and were probably deposited 

in similar low-energy, freshwater paleoenvironments. 

Freshwater habitats are required for the clams and snails 

found in the Olympia nonglacial sediments south of 

Ebey’s Landing, and for the mollusks found in similar 

sediments along the northern shore of Penn Cove 

(Polenz et al. 2005). The carbon-13 to carbon-12 ratios of 

the shells also suggest a freshwater setting.

About 18,000 years ago, the Puget Lobe of the 

Cordilleran ice sheet advanced from British Columbia to 

just south of Olympia, covering the entire Puget Lowland 

with glacial ice in the last major ice advance called the 

Fraser Glaciation (Washington State Department of 

Natural Resources 2010). The part of the Fraser 

Glaciation during which Cordilleran ice covered the 

Puget Lowland is called the Vashon Stade, and it is 

largely responsible for the present-day geomorphic 

features in the Puget Lowland. High-energy meltwater 

streams flowed from the front of the advancing glacier 

and deposited well-sorted sand and gravel over the 

region. The thickness of the Vashon Stade ice reached 

approximately 1,200–1,300 m (3,900–4,300 ft) on central 

Whidbey Island (Polenz et al. 2005).

Similar to previous glaciations, the Cordilleran ice sheet 

dammed the streams and rivers draining the Cascade 

Mountains. Flow was diverted south along the flanks of 
30 NPS Geologic Resources Division

the Cascades and then around the terminus of the ice 

sheet south of Olympia. Finally, the waters flowed out 

the Chehalis River Valley to the Pacific Ocean. Drumlin 

orientation on Whidbey Island indicates that ice flow 

was mostly confined to a north-south direction.

As the ice thinned near the end of the Vashon Stade, 

recessional outwash sands and gravels covered large 

areas south of Seattle. These deposits are an important 

source of raw materials for concrete and other 

construction uses (Washington State Department of 

Natural Resources 2010). Late in the glaciation, a local 

ice front stabilized at Coupeville and remained long 

enough to allow the deposition of the Partridge Gravel 

[map unit Qgom(e)]. Sediments in the Partridge Gravel 

represent marine and kame-delta depositional 

environments, and exemplify the development of some 

of the best sand and gravel deposits (Polenz et al. 2005; 

Michael Polenz, Geologist, Washington Department of 

Natural Resources, written communication, March 

2011). 

Marine shells discovered in the Partridge Gravel at Cedar 

Hollow in Ebey’s Landing National Historical Reserve 

may provide the oldest constraining radiocarbon dates 

for the breakup of the Vashon glacial ice and the 

beginning of the Everson Interstade (Carlstad 1992; 

Polenz 2005). To date, a marine shell found at Oak 

Harbor, a few kilometers north of the reserve, has 

yielded the oldest estimated date (13,650 B.P.) for the 

Everson Interstade. However, ice must have covered Oak 

Harbor and an ice front must have been present in Penn 

Cove when the Partridge Gravel was deposited. If an ice 

front had not been located in Penn Cove, then the 

outwash would have filled Penn Cove rather than 

forming the large delta terraces found east and west of 

Ebey’s Prairie. If an isolated block of stagnant ice had 

occupied Penn Cove, then melting ice would not have 

provided enough meltwater and sediment to produce the 

Partridge Gravel. Rather, seawater must have flooded the 

ice-free areas south and west of Penn Cove while Oak 

Harbor remained covered by ice. Therefore, marine 

shells found at Cedar Hollow would be older than those 

at Oak Harbor (Polenz 2005; Polenz et al. 2005).

As the Vashon Stade ice retreated, seawater may have 

flowed under the thinning ice front, lifting the ice and 

causing it to break apart into ice bergs over much of the 

region. The overprint of southwest drumlinization north 

of the Coupeville moraine suggests that the ice collapse 

across Admiralty Inlet removed the confining pressure in 

the central to northern Puget Lowland and triggered a 

reorientation of the ice flow to a southwestern direction. 

During the Everson Interstade, local sea level rose

66–70 m (216–229 ft). Glaciomarine drift deposits south 

of Lovejoy Point are about 67 m (220 ft) above present 

sea level. The Everson Interstade ended when postglacial crustal rebound exceeded global sea level rise, 

causing the land in the reserve area to emerge. Evidence 

from a glaciomarine deposit 3 m (10 ft) above sea level 

along the northern shore of Penn Cove suggests an age of 

12,690 years B.P. for the end of the Everson Interstade, 

thus suggesting that glaciation effectively ended in the 

reserve area somewhat earlier than 10,000 years B.P. 

(Polenz et al. 2005).

The fossil assemblage in the dune sand (map unit Qd) 

above the paleosol at Cedar Hollow suggests that the 

paleoenvironment was warmer and drier approximately 

10,000 years B.P. than it is today (Mustoe et al. 2005; 

Polenz 2005). Further study of the paleosol beneath the 

dune sand may provide additional information regarding 

the paleoenvironment and paleoclimate at the end of the 

Everson Interstade.

Except for dune development and bluff formation due to 

coastal erosion, the landforms and deposits in Ebey’s 

Landing National Historical Reserve have changed little 

since the end of the Everson Interstade. Dune 

development probably began about 10,000 years ago and 

continues along the western shore. Shoreline erosion 

began when sea level approximated modern sea level in 

the mid-Holocene.

The western coast of Washington continues to be an 

active plate tectonic zone, where the oceanic Juan de 

Fuca plate moves northeast and subducts beneath the 

North American plate at a rate of about 4 cm (1.6 in) per 

year (Booth et al. 2004). Seismographs record more than 

1,000 earthquakes each year due to plate subduction. 

The Puget Lowland is classified as a Seismic Risk Zone 3 

on a scale of 0 to 4, with 4 being the highest risk 

(Washington State Department of Natural Resources 

2010). In 1949 and 2001, the epicenters of damaging 

earthquakes with Richter scale magnitudes of 7.1 and 6.8, 

respectively, were centered under Olympia, and the 1965 

magnitude 6.5 earthquake was centered under 

Seattle/Tacoma. The most recent fault movement 

associated with documented surface rupture in the 

Whidbey Island area occurred between 1550 and 1850 

C.E. (Polenz et al. 2005).
EBLA Geologic Resources Inventory Report 31

Figure 21. Geologic timescale. Included are major life history and tectonic events occurring on the North American continent. Red lines 

indicate major unconformities between eras. Radiometric ages shown are in millions of years (Ma). Compass directions in parentheses 

indicate the regional location of individual geologic events. Drafted by Trista Thornberry-Ehrlich (Colorado State University) using data 

from the U.S. Geological Survey (http://pubs.usgs.gov/fs/2007/3015/) and the International Commission on Stratigraphy

(http://www.stratigraphy.org/view.php?id=25).
32 NPS Geologic Resources Division

Figure 22. Middle Jurassic paleogeographic map of western North America. Approximately 160 million years ago, the islands of 

Wrangellia began to be accreted to the North American continent. Oblique convergence between the North American and the Farallon 

plates created a transform (strike-slip) fault along the southwestern margin of North America. Volcanic islands (volcanic arcs) formed 

above subduction zones. White arrows indicate the general direction of plate movement. Black arrows indicate movement along the 

transform fault. The yellow star represents the approximate location of today’s Ebey’s Landing National Historical Reserve. Brown 

colors represent land surface. Relative depths of marine water are divided into shallow (light blue) and deep (dark blue). Base map by 

Ron Blakey, Colorado Plateau Geosystems, Inc., http://cpgeosystems.com/jur160seattle.html, accessed September 19, 2011. Annotation 

by the author.
EBLA Geologic Resources Inventory Report 33

Figure 23. Pleistocene paleogeographic map of North America during a Pleistocene Ice Age. Approximately 126,000 years ago, the area 

of today’s Ebey’s Landing National Historical Reserve (yellow star) was covered by the Cordilleran Ice Sheet. Base map by Ron Blakey, 

Colorado Plateau Geosystems, Inc., http://cpgeosystems.com/namQ.jpg, accessed September 19, 2011. Annotation by the author.

EBLA Geologic Resources Inventory Report 35

Geologic Map Data

This section summarizes the geologic map data available for Ebey’s Landing National 

Historical Reserve. It includes a fold-out geologic map overview and a summary table 

that lists each map unit displayed on the digital geologic map for the park. Complete GIS 

data are included on the accompanying CD and are also available at the Geologic 

Resources Inventory (GRI) publications website: 

(http://www.nature.nps.gov/geology/inventory/gre_publications.cfm).

Geologic Maps

Geologic maps facilitate an understanding of an area’s 

geologic framework and the evolution of its present 

landscape. Using designated colors and symbols, 

geologic maps portray the spatial distribution and 

relationships of rocks and unconsolidated deposits. 

Geologic maps also may show geomorphic features, 

structural interpretations, and locations of past geologic 

hazards that may be prone to future activity. 

Additionally, anthropogenic features such as mines and 

quarries may be indicated on geologic maps. 

Source Maps

The Geologic Resources Inventory (GRI) team converts 

digital and/or paper source maps into the GIS formats 

that conform to the GRI GIS data model. The GRI digital 

geologic map product also includes essential elements of 

the source maps including unit descriptions, map legend, 

map notes, references, and figures. The GRI team used 

the following source maps to create the digital geologic 

data for Ebey’s Landing National Historical Reserve: 

Polenz, M., S.L. Slaughter, J.D. Dragovich, and G.W. 

Thorsen. 2005. Geologic map of the Ebey’s Landing 

National Historical Reserve, Island County, 

Washington. Washington Division of Geology and 

Earth Resources: Open-File Report 2005-2 (scale 

1:24,000).

These source maps provided information for the 

“Geologic Issues,” “Geologic Features and Processes,” 

and “Geologic History” sections of this report.

Geologic GIS Data

The GRI team implements a GIS data model that 

standardizes map deliverables. The data model is 

included on the enclosed CD and is also available online 

(http://science.nature.nps.gov/im/inventory/geology 

/GeologyGISDataModel.cfm). This data model dictates 

GIS data structure including layer architecture, feature 

attribution, and relationships within ESRI ArcGIS 

software. The GRI team digitized the data for Ebey’s 

Landing National Historical Reserve using data model 

version 2.1.

GRI digital geologic data for Ebey’s Landing National 

Historical Reserve are included on the attached CD and 

are available through the NPS Natural Resource 

Information Portal (https://nrinfo.nps.gov/ 

Reference.mvc/Search). Enter “GRI” as the search text 

and select Ebey’s Landing National Historical Reserve

from the unit list. The following components and 

geology data layers are part of the data set:

• Data in ESRI geodatabase and shapefile GIS formats

• Layer files with feature symbology

• Federal Geographic Data Committee (FGDC)–

compliant metadata

• An ancillary map information document (PDF) that 

contains all of the ancillary map information and 

graphics, including geologic unit correlation tables and 

map unit descriptions, legends, and other information 

captured from source maps.

• An ESRI map document file (.mxd) that displays the 

digital geologic data
36 NPS Geologic Resources Division

Table 2. Geology data layers in the Ebey’s Landing National Historical Reserve GIS data.

Data Layer Code On Geologic Map Overview?

Geologic Cross Section Lines EBLASEC Yes

Geologic Attitude Observation 

Localities

EBLAATD No

Geologic Observation Localities EBLAGOL No

Geologic Sample Localities EBLAGSL No

Mine Point Features EBLAMIN No

Hazard Feature Lines EBLAHZL Yes

Geologic Line Features EBLAGLF Yes

Faults EBLAFLT Yes

Linear Geologic Units EBLAGLN Yes

Geologic Contacts EBLAGLGA Yes

Geologic Units EBLAGLG Yes

Note: All data layers may not be visible on the geologic map overview graphic.

Geologic Map Overview

The fold-out geologic map overview displays the GRI 

digital geologic data draped over a shaded relief image of 

Ebey’s Landing National Historical Reserve and includes 

basic geographic information. For graphic clarity and 

legibility, not all GIS feature classes are visible on the 

overview. The digital elevation data and geographic 

information are not included with the GRI digital 

geologic GIS data for the park, but are available online 

from a variety of sources.

Map Unit Properties Table

The geologic units listed in the fold-out map unit 

properties table correspond to the accompanying digital 

geologic data. Following overall structure of the report, 

the table highlights the geologic issues, features, and 

processes associated with each map unit. The units, their 

relationships, and the series of events the created them 

are highlighted in the “Geologic History” section. Please 

refer to the geologic timescale (fig. 21) for the geologic 

period and age associated with each unit.

Use Constraints

Graphic and written information provided in this section 

is not a substitute for site-specific investigations, and 

ground-disturbing activities should neither be permitted 

nor denied based upon the information provided here. 

Minor inaccuracies may exist regarding the location of 

geologic features relative to other geologic or geographic 

features on the overview graphic. Based on the source 

map scale (1:24,000) and U.S. National Map Accuracy 

Standards, geologic features represented here are within 

12 meters / 40 feet (horizontally) of their true location.

Please contact GRI with any questions.
Qgom(e)

Qgdm(e)

Qgt(v)

Qgom(e)

Qgdm(e)

Qd

Qp

Qb

Qgom(ee)

Qgdm(e) Qs

Qgt(v)

Qs

Qgt(v)

Qgim(e)

Qgdm(e)

Qgog(e)

Qgt(v)

Qd

Qgt(v)

Qb

Qgom(ee)

Qgog(e)

Qgom(ee)

Qgt(v)

Qgdm(e)

Qgom(ee)

Qgog(e)

Qd

Qgt(va)

Qgom(ee)

Qmf(e)

Qb

Qgt(va)

Qml

Qgt(v)

Qml

Qml

Qgos(e)

Qgdm(e)

Qgdm(e)

Qgog(e)

Qgdm(els)

Qgdm(e)

Qgom(ee)

Qgt(v)

Qgim(e)

Qgos(e)

Qgdm(e)

Island County

Historical Museum

Reserve Information

Jacob Ebey House

Visitor Contact Station (seasonal)

Overview of Digital Geologic Data

for Ebey's Landing NH Reserve

National Park Service

U.S. Department of the Interior

NPS Boundary

Hazard Feature Lines

landslide scarp

Geologic Line Features

terrace escarpment

Faults

unknown offset/displacement, concealed

unknown offset/displacement, inferred

Linear Geologic Units

Qgd - Fraser Glaciation - Vashon Stade; 

Vashon and Everson drift, undivided

Qc(o) - Olympia Nonglacial Interval; nonglacial deposits

Geologic Contacts

known or certain

approximate

inferred

map boundary

water or shoreline

Geologic Units

Water

Qf - Fill

Qml - Modified land

Qb - Beach deposits

Qd - Dune deposits

Qp - Peat

Qm - Marsh deposits

Qmw - Mass wasting deposits

Qls - Landslide deposits

Qs - Late Pleistocene sand

Qgom(ee) - Fraser Glaciation - Everson Interstade; 

glaciomarine drift, emergence (beach) facies

Qmf(e) - Fraser Glaciation - Everson Interstade; fan deposits

Qgdm(e) - Fraser Glaciation - Everson Interstade; 

glaciomarine drift, undivided

Qgdm(els) - Fraser Glaciation - Everson Interstade; landslides

Qgos(e) - Fraser Glaciation - Everson Interstade; glaciomarine sand deposits

Qgim(e) - Fraser Glaciation - Everson Interstade; ice-marginal moraine

Qgom(e) - Fraser Glaciation - Everson Interstade; Partridge Gravel

Qgog(e) - Fraser Glaciation - Everson Interstade; 

high-energy outwash gravel

Qgt(v) - Fraser Glaciation - Vashon Stade; till

Qgt(va) - Fraser Glaciation - Vashon Stade; Ablation till

Qga(v) - Fraser Glaciation - Vashon Stade; advanced outwash

Qga(vs) - Fraser Glaciation - Vashon Stade; 

sand-dominated advanced outwash

Qgd - Fraser Glaciation - Vashon Stade; Vashon and Everson drift, undivided

Qc(o) - Olympia Nonglacial Interval; nonglacial deposits

Qgd(p) - Possession Glaciation; Possession Drift

Qc(w) - Interglacial Deposits of the Whidbey Formation

Qgd(d) - Double Bluff Glaciation; Double Bluff Drift

Qc - Pre-Frasier Nonglacial, undivided

Qu - Pleistocene deposits, undivided

Produced by the Geologic Resources Inventory June 2011

Ebey's Landing National Historical Reserve

Washington

0 0.5 1 1.5

Miles

0 1 2 3

Kilometers

North

P E N N

C O V E

CROCKETT

LAKE

20

20

20

W H I D B E Y

I S L A N D

ADMIRALTY

BAY

S T R A

I

T

O

F

J U A N

D E

F U

C A

S A R AT O G A

PA S S A

G E

Geologic Cross Section Lines

A-A’, B-B’

UTM NAD83 ZONE 10N

This figure is an overview of compiled digital geologic data. It is not a substitute for site-specific investigations. 

Minor inaccuracies may exist regarding the location of geologic features relative to other geologic or 

geographic features on the figure. Based on the source map scale (1:24,000) and U.S. National Map 

Accuracy Standards, geologic features represented here are within 12 meters / 40 feet (horizontally) of their 

true location.

This figure was prepared as part of the NPS Geologic Resources Division’s Geologic Resources Inventory. 

The source map used in creation of the digital geologic data product was:

Polenz, M., Slaughter, S.L., Dragovich, J.D., and Thorsen, G,W., 2005. Geologic Map of the Ebey's Landing 

National Historical Reserve, Island County, Washington (scale 1:24,000). Open File Report 2005-2. 

Washington Division of Geology and Earth Resources.

Digital geologic data and cross sections for Ebey’s Landing National Historical Reserve, and all other digital 

geologic data prepared as part of the Geologic Resources Inventory, are available online at the NPS Natural 

Resource Information Portal: https://nrinfo.nps.gov/Reference.mvc/Search. (Enter “GRI” as the search text 

and select Ebey’s Landing National Historical Reserve from the unit list.)

A-A’

B-B’
EBLA Geologic Resources Inventory Report 39

Map Unit Properties Table: Ebey’s Landing National Historical Reserve

* = Landscape Character Areas after Gilbert (1985).

Age Map Unit

(Symbol) Geologic Description and Features Erosion Resistance

Suitability for 

Infrastructure Hazards Paleontological Resources

Cultural 

Resources

Mineral 

Occurrence

Major Landscape 

Character Area*

Geological 

Significance

QUATERNARY

(Holocene)

Historic (since about 1850)

Fill

(Qf)

Clay, silt, sand, gravel, organic matter, rip-rap, and debris emplaced to elevate and

reshape the land surface; includes engineered and non-engineered fills; shown where 

fill placement is relatively extensive, readily verifiable, and appears sufficiently thick 

to be of geotechnical significance. Underlies parts of Highway 28; forms barrier 

between Kennedy’s Lagoon and Penn Cove.

Variable, 

depending on 

material and

subsequent 

vegetation.

Common byproduct of

development. 

Variable depending 

on material, 

compaction, and 

location.

Commonly 

loose, 

liquefiable, 

and prone to 

erosion.

None.

Represents 

relatively 

recent 

activities.

None.

Minor exposures in 

Crockett Prairie, 

Kettle and Pratt 

Woodlands, Penn 

Cove, San de Fuca 

Uplands, and West

Coastal Strip.

None.

Modified 

land

(Qml)

Local sediment, ranging from clay to gravel, mixed and reworked by excavation 

and/or redistribution to modify topography; includes mappable sand and gravel pits 

excavated mostly into unit Qgom(e). Mapped along western shoreline south of 

Partridge Point.

Variable. Limited areal 

extent.

None 

documented; 

potential 

slumping in 

pits.

None.

Represents 

relatively 

recent 

activities.

Sand and 

gravel pits are 

remnants of 

mining.

Minor exposures in 

most areas. None.

QUATERNARY

(Pleistocene-Holocene)

Postglacial Deposits

Beach 

deposits

(Qb)

Sand and cobbles; may include boulders, silt, pebbles, and clay; pebble-sized and

larger clasts, typically well-rounded and oblate; locally well-sorted; loose; typically a 

mix of sediment locally derived from shoreline bluffs and underlying deposits and/or

carried in by longshore drift.

Low, but 

replenished by 

longshore 

processes and 

mass wasting 

from upslope.

Low. Beaches tend 

to erode; unstable 

foundation.

Tides may be a 

potential 

visitor safety 

issue.

Unlikely, but 

prone to 

transient 

exposure.

Artifacts 

subject to 

intermittent 

exposure but 

unlikely to be 

preserved.

Quartz-rich 

sand.

West Coastal Strip; 

Crokett Prairie; 

Penn Cove.

Modern processes 

form sedimentary 

structures just as 

they did in the past.

Dune 

deposits

(Qd)

Hills and ridges of wind-blown sand; moderately to well sorted; deposited on upland 

surfaces and in kettle sidewalls along or near west-facing shoreline bluffs north of 

Ebey’s Landing. Age estimates indicate deposition of some dunes began during the 

early Holocene. Dune morphology suggests that the depositional environment lacked

the forests that cover most of these dunes today, but minimal soil development and

location of the dunes within 0.8 km (0.5 mi) of the present-day shoreline bluffs 

suggest deposition may also be recent and ongoing. Estimated radiocarbon ages of 

8,840 ±50 and 8,280 ±40 years before present (BP). Located near unstable shoreline 

bluffs; north of Ebey’s Landing.

Low. Low. No significant 

hazards.

Kettle filled with 

wind-blown 

sands contained 

snails, birds, and 

a variety of 

mammalian 

bones.

Artifacts 

unlikely to be 

preserved due 

to exposure.

Quartz-rich 

sand.

Kettle and Pratt 

Woodlands.

Fossils may 

represent only 

known record of 

continental animals 

from Pacific 

Northwest during 

early Holocene 

(Mustoe et al. 2005).

Peat

(Qp)

Organic and organic-matter-rich mineral sediments deposited in closed depressions; 

includes peat, muck, silt, and clay in and adjacent to wetlands; unit Qp is the 

freshwater equivalent of unit Qm and may locally grade down to that unit. Isolated 

deposits in kettles and near Crockett Lake lowlands. Typically, associated with 

wetlands in modern environment.

High. Low 

energy setting 

saturated and 

stabilized by 

organic matter.

Low.

Prone to 

intense 

shaking during 

earthquakes.

Possible 

Holocene plant, 

vertebrate and 

invertebrate 

remains.

Artifacts may 

be buried in 

peat.

Peat. Crockett Prairie.

May convert to 

lignite or coal with 

increased pressure, 

temperature, and 

time.

Marsh 

deposits

(Qm)

Organic and organic-matter-rich mineral sediments deposited in a saltwater or 

brackish-marsh (estuarine or lagoonal) environment. Mapped near shorelines. 

Isolated with limited areal extent.

High. Water 

saturated, lowenergy 

environment.

Low. 

Prone to 

intense 

shaking and 

liquefaction 

during 

earthquakes.

Possible 

Holocene plant, 

vertebrate and 

invertebrate 

remains.

Artifacts may 

be buried in 

marsh.

None.

Minor units in West 

Coastal Strip, San de 

Fuca Uplands.

Post-glacial record 

of land level and/or 

sea level history.

Mass 

wasting 

deposits

(Qmw)

Boulders, gravel, sand, silt, and clay; generally unsorted but may be locally stratified; 

typically loose; shown along mostly colluvium-covered or densely vegetated slopes 

that are demonstrably unstable or appear potentially unstable; contains exposures of 

underlying units and landslides that cannot be mapped with confidence or are too 

small to show as separate features. Unstable, ephemeral deposits along bluffs.

Low. Low. Unstable 

deposits.

Potential 

reactivation of 

unstable 

slopes.

Unlikely. 

Transient 

deposits.

Low potential 

for preservation of 

artifacts.

None. Minor unit mapped 

in coastal areas.

Reflects processes 

that occurred along 

shorelines in the 

past.
* = Landscape Character Areas after Gilbert (1985).

EBLA Geologic Resources Inventory Report 40

Age Map Unit

(Symbol) Geologic Description and Features Erosion Resistance

Suitability for 

Infrastructure Hazards Paleontological Resources

Cultural 

Resources

Mineral 

Occurrence

Major Landscape 

Character Area*

Geological 

Significance

QUATERNARY

(Pleistocene-Holocene)

Postglacial Deposits

Landslide 

deposit

(Qls)

Gravel, sand, silt, clay, and boulders in slide body and toe, and underlying units in 

scarp areas; angular to rounded clasts; unsorted; generally loose, unstratified, broken, 

and chaotic, but may locally retain primary bedding; may include liquefaction 

features; deposited by mass-wasting processes other than soil creep and frost heave; 

typically unconformable with surrounding units; includes active and inactive slides; 

shown where scale permits. Absence of a mapped slide does not imply absence of 

sliding or hazard. Unstable ephemeral deposits along bluffs.

Low. Wave 

action along 

beaches removes 

most slide 

deposits.

Low. Unstable 

deposits.

All shoreline 

bluffs are 

subject to 

episodic 

landsliding 

and resultant 

bluff retreat.

Unlikely. 

Transient 

deposits.

Low potential 

for preservation of 

artifacts.

None. Minor unit mapped 

in coastal areas.

Reflects processes 

that occurred along 

shorelines in the 

past.

Late

Pleistocene 

sand

(Qs)

Fine sand to silt; light gray where fresh, light-tan to reddish brown where weathered; 

moderately well sorted; blankets much of the map area as a 0.2–1.2 m (0.5–4 ft) thick 

sheet that typically forms topsoil; mapped only where thickness appears to exceed 1.5 

m (5 ft); well to very well drained; grain size, sorting, and morphology suggest windblown origin for some exposures, but elsewhere, mineralogy, poor sorting, and high 

angularity suggest till or glaciomarine drift [Qgdm(e), Qgt(v), and Qgt(va)] or mixed 

sources; appears to represent a postglacial, late Pleistocene pulse of sedimentation 

because it is stratigraphically beneath, and typically separated by a paleosol from 

Holocene dunes (Qd) that lack a similar degree of soil development.

Low except 

where stabilized 

by vegetation on 

relatively flat 

topography 

inland from 

Ebey’s Landing.

Suitable for roads 

and infrastructure, 

but limited 

mappable 

exposures.

None. Unlikely.

Unknown. 

Probable 

archaeological 

sites.

Quartz-rich 

sand. Ebey’s Prairie.

Paleosol in top of 

unit may reflect a 

late Pleistocene to 

early Holocene 

climate conducive 

to more rapid soil 

development than 

today’s modern 

climate.

QUATERNARY

(Pleistocene)

Deposits of the Fraser Glaciation (Everson Interstade)

Glaciomarine 

drift,

beach facies

[Qgom(ee)]

Sand and gravel, locally silty; loose; typically only a few feet thick; underlain by 

Qgdm(e) or Qgom(e), but may rest on older sediments north and west of Penn Cove 

and along parts of the slope east of Ebey’s Prairie. Characteristic subtle benches at 

varying elevations represent paleo–beach berms. Contains the youngest facies of 

glaciomarine drift but may also include terrestrial deposits. Mapped as outwash to 

maintain continuity with maps to the north. Underlies roads and buildings at Fort 

Casey.

Variable. 

Typically welldrained and 

stabilized by 

vegetation.

Suitable for roads 

and infrastructure. None. Unlikely.

Unknown. 

Potential for 

archaeological 

sites.

Sand and 

gravel.

Crockett Prairie, 

Ebey’s Prairie, Fort 

Casey Uplands, San 

de Fuca Uplands.

Emergent deposits 

record a falling 

relative sea level at 

the end of the 

Everson Interstade.

Fan 

deposits

[Qmf(e)]

Sand, fine gravel, silt, and clay; variably sorted; loose; bedded; consists of either 

terrigenous nearshore marine deltaic or terrestrial alluvial fans that record a late 

Everson Interstade (?), onshore hydrologic regime conducive to surface runoff in 

loose, well-drained units like Qgom(e); located at the foot of small, relict valleys that 

lack modern streams and were incised into Qgom(e) or other easily eroded deposits. 

If unit deposition is tied to sea level change, valley incision and fan deposition ceased 

when relative sea level dropped sufficiently below the head of the fan to cause the 

groundwater table to lower, resulting in termination of surface runoff capable of 

incision. Valley incision into and fan deposition on the delta front landform in 

Qgom(e) indicate that Partridge Gravel deposition had locally ceased; thus, the ice 

front that had supplied the water that deposited the Partridge Gravel had locally 

reduced meltwater supply, and the runoff that deposited unit Qmf(e) near Coupeville 

was likely fed by other sources. Best viewed as neither glaciomarine drift nor 

outwash, although deposition was likely coeval (and may interfinger) with nearby 

deposition of glaciomarine drift. Assigned to the Everson Interstade based on 

presumed association with Everson sea level. Mapped in three fan-shaped exposures 

of limited areal extent.

Variable. More 

resistant to 

erosion where 

the unit has been 

stabilized by 

vegetation.

Low due to minor 

exposures of limited 

areal extent. The 

largest area contains 

a road and

buildings.

None. Unlikely.

Unknown. 

Limited areal 

extent.

Quartz-rich 

sand and 

gravel.

Minor unit with 

limited areal extent 

mapped along the 

southwestern 

border of Parker 

and Patmore 

Woodlands.

May mark a climatic 

shift or an elevated 

(but dropping) 

relative sea level late 

in the Everson 

Interstade.
* = Landscape Character Areas after Gilbert (1985).

EBLA Geologic Resources Inventory Report 41

Age Map Unit

(Symbol) Geologic Description and Features Erosion Resistance

Suitability for 

Infrastructure Hazards Paleontological Resources

Cultural 

Resources

Mineral 

Occurrence

Major Landscape 

Character Area*

Geological 

Significance

QUATERNARY

(Pleistocene)

Deposits of the Fraser Glaciation (Everson Interstade)

Glaciomarine 

drift, 

undivided

[Qgdm(e)] 

Landslides 

[Qgdm(els)]

Qgdm(e): Clayey to silty diamicton with variable content of gravel-sized clasts; also 

includes silt, clay, sand, and combinations thereof; contains marine shells; weathered 

color most commonly buff but ranges to olive-gray, ash-gray, or white; dark-gray 

where unweathered; dry face characteristically includes vertical desiccation cracks 

with dark-brown staining; massive to rhythmically bedded, commonly with sharp 

upper and lower, unit-bounding unconformities; mostly loose and soft but locally 

hard and compact. Some exposures are very like till, but till generally lacks fossils, and

glaciomarine drift generally has a finer-grained, smoother-feeling matrix, and is more 

likely to be stratified, more likely to be buff-colored, and typically less compact (and

less water-restrictive) than till. Till-like deposits are most prominent along elevated 

portions of Blowers Bluff, the north shore of Penn Cove, and the cliff between Ebey’s 

Landing and Fort Casey. Locally divided into Qgdm(els).

Qgdm(els): Apparent landslides that lack evidence of recent activity. Dominated by 

glaciomarine drift material that may be slightly looser than glaciomarine drift outside 

the slump area. May be Everson Interstade(?) submarine(?) slumps that do not 

necessarily pose a slide hazard.

High where 

stabilized by 

vegetation as in 

Ebey’s Prairie; 

variable along 

bluffs.

High. Underlies 

unimproved and

improved roads, 

buildings, and 

towns.

Commonly 

forms vertical 

faces prone to 

sudden failure 

along 

desiccation 

cracks.

Contains marine 

shells; one shell 

yielded a 

radiocarbon 

date of 13,650 

years BP.

Unknown. 

Potential for 

archaeological 

sites.

None 

(diamicton).

Major map unit. 

Includes:

Coupeville,

Crockett Prairie,

Ebey’s Prairie,

Fort Casey Uplands,

San de Fuca 

Uplands.

Consists of sea-floor 

sediment, and its 

variegated character 

appears to reflect 

initial proximity of 

the ice front. Age 

spans the entire 

Everson Interstade.

Glaciomarine

sand 

deposits

[Qgos(e)]

Sand, pebbly sand, and silty fine sand with locally thin interbeds of silt and rare 

cobbly sand; mostly structureless to locally plane-bedded, laminated, or rarely crossbedded; locally complexly interlayered with other glaciomarine drift; includes minor 

glaciofluvial deposits. Fining trends and sedimentary structures suggest deposition in 

a shallow glaciomarine setting such as foreshore deposits or submarine fan turbidites.

Except for minor areas along the northern border of the reserve, the unit is mapped 

north of the reserve.

Low, except 

where stabilized 

by vegetation.

Underlies roads and 

buildings. Potential 

farmland.

None.

Unlikely, but 

may contain 

marine shells.

Potential for 

archaeological 

sites.

Sand.

Part of the San de 

Fuca Uplands, but 

mostly mapped 

north of the reserve, 

which does not have 

defined landscape 

areas.

Sedimentary 

structures suggest a 

shallow glaciomarine or submarine fan turbidite 

depositional 

environment.

Icemarginal 

moraine

[Qgim(e)]

Cobbly to bouldery, angular to rounded gravel with loose, powdery matrix, abundant

void spaces, and abundant erratics on the surface; forms a gentle, 150–240 m (500–800 

ft)– wide east–west ridge across Coupeville; marks the ice margin during Everson 

Interstade, likely deposited before the shell dated in Qgdm(e).

High. Stabilized 

by vegetation.

High. Underlies 

roads, buildings, 

and infrastructure.

None. Highly unlikely.

Unknown. 

Potential for 

archaeological 

sites.

Gravel. Coupeville.

Ice margin during 

the early part of the 

Everson Interstade.

Partridge 

Gravel

[Qgom(e)]

Sand, gravel, and sand-gravel mixtures with minor interlayered silt and silty sand; at 

least 64 m (210 ft) thick above sea level southeast of Partridge Point, with well records 

locally suggesting an additional 41 m (135 ft) below sea level; forms angle-of-repose 

slopes, such as at Partridge Point. Includes three outwash facies that compose an 

upward-coarsening, marine, kame-delta–turbidite complex: 1) a mostly horizontally 

bedded, sand-dominated, bottom-set sea floor facies with common low-energy 

gravity flow cross-bedding, flame structures, and other soft sediment deformation 

features, but apparently lacking dropstones; 2) an overlying foreset-bedded sand and

gravel facies; and 3) a capping, top-set, channelized gravel and sand facies that

coarsens locally to a bouldery gravel and reflects a shallow-water deltaic to subaerial, 

braided-stream environment with abundant cut-and-fill cross-bedding. Many 

exposures of the bottom-set sand facies include sparse, randomly distributed 

inclusions and apparently gravity-sorted trains of sand- to fine- gravel-sized, detrital 

fragments of peat, charred wood, charcoal, coal, pumice, and dacite. Tephra deposits 

may be re-worked from nearby units, mostly Qc(o). Assuming an average thickness of 

30–76 m (100–250 ft), the unit holds about 0.8 to 2.5 km3 (0.2 to 0.6 mi3) of sand and

gravel. Areally extensive throughout the reserve especially in the Partridge Point area, 

north of Ebey’s Landing, and Smith Prairie.

Variable. Low 

along some 

bluffs. Moderate

where the unit 

forms relatively

stable angle-ofrepose slopes, 

and high where 

stabilized by 

vegetation on 

relatively flat 

topography.

High. Underlies 

structures.

Unstable along 

some slopes, 

especially 

where 

undercut.

Possible 

invertebrate 

shells preserved 

in marine facies.

Potential for 

archaeological

sites.

Sand and 

gravel. 

Outwash sand 

and gravel are 

important 

sources for 

concrete and

construction 

uses south of 

Seattle.

Primary map unit in 

Parker and Patmore 

Wood-lands and

Smith Prairie. One 

of two major map 

units in Kettle and 

Pratt Woodlands 

and West Coastal 

Strip.

Type section is at 

Partridge Point. 

Tephra chemistry 

and field relations 

favor a Glacier Peak 

origin for tephra 

(may be reworked 

from older geologic 

deposits). Age is 

early Everson 

Interstade, 

sometime after the

initial incursion of 

marine water into 

the Puget Lowland 

but predating the

marine shell in 

Qgdm(e) dating to

13,650 ±350 years 

BP.
* = Landscape Character Areas after Gilbert (1985).

EBLA Geologic Resources Inventory Report 42

Age Map Unit

(Symbol) Geologic Description and Features Erosion Resistance

Suitability for 

Infrastructure Hazards Paleontological Resources

Cultural 

Resources

Mineral 

Occurrence

Major Landscape 

Character Area*

Geological 

Significance

QUATERNARY

(Pleistocene)

Deposits of the Fraser Glaciation

(Everson Interstade)

Highenergy 

outwash 

gravel

[Qgog(e)]

Diverse deposit of gravel with lenses of sand, silt, and clay and inclusions of bouldersized, subangular to well-rounded silt and clay rip-up clasts and channel lag gravel 

derived from massive to well-bedded, compact, pre-Fraser deposits of fine sediment; 

crudely to well bedded, locally unbedded, and commonly including steep bedding, 

gravelly incisions (intrusions?) into underlying units, and other indicators of a highenergy flow regime; typically supports vertical bluff faces but locally forms angle-ofrepose slopes; widely exposed beneath Qgdm(e) along the Penn Cove shoreline 

between Coupeville and Blowers Bluff, where it steeply truncates at least 12 m (40 ft) 

of pre-Fraser section. Like Qgom(e), unit is overlain by Qgdm(e). Southwest of Penn 

Cove, locally grades up into and thus is a lateral facies equivalent of the Partridge 

Gravel. For that reason and because the unit is apparently nowhere overlain by 

convincing exposures of Vashon Till (Qgt(v)), assigned to the Everson Interstade. 

Separated from Partridge Gravel because Partridge Gravel is marine-deltaic and lacks

the characteristics of high-energy flow that mark this unit. The unit is not areally

extensive and is primarily present within vertical bluffs along the shoreline of Penn 

Cove.

Low to 

moderate. 

Erodes to angleof-repose 

slopes. Primarily 

shoreline 

deposits that 

may be exposed 

to wave erosion.

Low. Limited areal 

extent. 

The unit is 

part of vertical 

bluff faces that 

may collapse.

None.

Unlikely due 

to limited 

exposures 

within the 

vertical bluffs.

Gravel, but not 

extensive in 

the reserve. 

South of 

Seattle, 

outwash sand 

and gravel are 

important 

sources of raw 

materials for 

concrete and 

construction.

Minor unit with 

limited areal extent. 

Mapped in Kettle 

and Pratt 

Woodlands, Penn 

Cove, and San de 

Fuca Uplands.

Interpreted as 

dominantly a 

subglacial flow 

deposit, except in

upland areas 

between Route 20 

and Penn Cove near 

the northern

boundary of the 

map, where the 

depositional and 

temporalstratigraphic setting 

is unclear.

Deposits of the Fraser Glaciation (Vashon Stade)

Till

[Qgt(v)]

Ablation till

[Qgt(va)]

Primarily mapped north of Penn Cove.

Qgt(v): Mix of clay, silt, sand, and gravel; gray where fresh, light yellowish-brown 

where oxidized; unsorted; highly compacted; very low permeability; commonly 

matrix-supported, but locally clast supported; matrix more angular than waterworked sediments, resulting in a grittier feel than the matrix of Qgdm(e); cobbles and

boulders commonly faceted and/or striated; forms a patchy cover varying from less 

than 0.15 m (0.5 ft) to greater than 15 m (50 ft) thick, with thicknesses of 3–9 m (10–30 

ft) most common; may include outwash and ablation till that are too thin to 

substantially mask the underlying, rolling till plain; locally capped with 0.15–1.2 m 

(0.5–4 ft) of sand that is equivalent to Qs but too thin to be mapped separately; up to 

house-sized erratic boulders commonly signal that till is underfoot, but such boulders 

may also occur as dropstones or lag deposits where the underlying deposits have been 

modified by meltwater; modern soil typically caps loose surface sediment, but the 

underlying till is unweathered; may include flow banding; forms vertical faces in 

coastal bluffs. Locally resembles Qgdm(e). Lies between overlying Qgdm(e) and

underlying Qga(v) and Qga(vs). Stratigraphic position relative to Qgog(e) remains 

unresolved. May include local exposures of older till similar in stratigraphic position, 

lithology, and appearance.

Qgt(va): Unsorted, unstratified melt-out deposit of loose gravel, sand, silt, and clay.

High, 

resembling 

concrete where 

well-developed, 

but exposures 

along bluffs can 

be unstable.

High. Underlies 

roads, buildings, 

and other 

infrastructure.

Forms vertical 

faces in coastal 

bluffs along 

Penn Cove 

shoreline and 

thus may

contribute to 

bluff collapse. 

None.

Unlikely. Unit 

was deposited 

by a glacier 

when the 

region was 

covered 

beneath 

thousands of 

feet of ice.

Potential 

landscaping 

material 

(boulders).

Fort Casey Uplands; 

San de Fuca 

Uplands.

Deposited as 

diamicton directly 

by Vashon Stade 

glacier ice.

Local and nearby 

age control 

constrains the age of 

the unit to between 

about 18,000 years 

BP and sometime 

before deposition of 

the shell in Qgdm(e) 

that dates to 13,650 

±350 years BP.

Advanced 

outwash 

[Qga(v),

Qga(vs)]

Qga(v): Sand and pebble to cobble gravel with some bouldery facies; local silt and

clay; may contain till fragments; gray to grayish-brown and grayish-orange; clasts 

well-rounded; typically well-sorted and clean except in some ice-proximal deposits 

near the top of the unit; compact, but in many exposures only minimally cohesive; 

parallel-bedded, locally cross-bedded; less than 6 m (20 ft) thick in most exposures; 

commonly overlain by Qgt(v), along a sharp contact and stratigraphically above 

Qc(o); commonly forms angle-of-repose benches within coastal bluffs. Locally 

divided into Qga(vs).

Qga(vs): Sand-dominated advance outwash. May overlie impermeable deposits on 

steep slopes.

Variable. 

Exposures are

too limited in 

areal extent to 

map. Finer 

sediment tends 

to erode more 

readily than 

coarser-grained 

material.

Low due to few 

exposures and 

limited areal extent.

Forms angleof-repose 

benches 

within coastal 

bluffs. May 

contribute to 

landslides and

bluff retreat. 

Qga(vs) is 

prone to 

sudden 

landslides 

along steep 

slopes.

Not recognized 

to be 

fossiliferous in 

the reserve, but 

contains 

mammoth 

remains in 

British 

Columbia.

Unknown and 

unlikely. 

Depositional 

environment 

very 

inhospitable 

and dynamic.

Sand and 

gravel.

Minor unit mapped 

along the coastline 

of Penn Cove and 

West Coastal Strip.

Age is bracketed to 

between about 

20,000 and 18,000

years BP by local 

and nearby age 

control from within 

the underlying 

Qc(o) and an 

estimate of Vashon 

ice arrival
* = Landscape Character Areas after Gilbert (1985).

EBLA Geologic Resources Inventory Report 43

Age Map Unit

(Symbol) Geologic Description and Features Erosion Resistance

Suitability for 

Infrastructure Hazards Paleontological Resources

Cultural 

Resources

Mineral 

Occurrence

Major Landscape 

Character Area*

Geological 

Significance

QUATERNARY

(Pleistocene)

Everson 

Insterstade and 

Vashon Stade:

Vashon and 

Everson drift, 

undivided

(Qgd)

Glaciomarine drift [Qgdm(e)], till [Qgt(v)], and advance outwash [Qga(v) and

Qga(vs)] combined into single unit where map scale or exposure do not permit 

separate presentation. Only two exposures are mapped along the western bluff.

See specific 

units.

Low. Limited areal 

extent. Bluff collapse. None.

Unknown. 

Limited areal 

extent.

Patchy sand, 

gravel, and 

boulders.

Minor unit mapped 

along West Coastal 

Strip.

See specific units.

Deposits of the 

Olympia 

Nonglacial 

Interval:

Olympia 

Nonglacial 

Interval

[Qc(o)]

Silt, clay, sand, and local lenses and interbeds of fine gravel; includes the West Beach 

(north of Partridge Point) silt facies interpreted as loess; compact; typically 

horizontally bedded to massive; commonly forms vertical bluffs; silt facies locally 

contain sparse gastropod fossils. Petrographic study indicates that alluvial facies 

reflect ancestral Skagit River provenance. Sparse, local Glacier Peak dacite and

pumice pebbles, such as those found to the east of Long Point are chemically 

indistinguishable from lahar runout deposits within the Whidbey Formation [Qc(w)], 

but no lahar runout deposits were recognized in Qc(o). Age of the West Beach silt is 

constrained in the map area to about 37,000 to 27,000 years BP by radiocarbon dates 

from overlying and underlying units. May include fine-grained early Vashon advance 

deposits, such as at north Penn Cove, where the upper radiocarbon date and

sedimentary characteristics of overlying silty sediment may be compatible with the 

early Vashon Stade. The limited exposures are mapped within bluffs along the 

western shore and at Blowers Bluff.

Low. Subject to 

wave and storm 

activity.

Low due to limited 

accessibility. 

Exposed in 

vertical bluffs 

and thus may 

contribute to 

bluff collapse 

along 

coastline.

Gastropod 

fossils. 

Mastodon tusk 

(proboscidean) 

found south of 

Ebey’s Prairie. 

Plant fossils and 

pollen.

Unlikely (preFraser and 

glacial).

None.

Minor unit that is 

mapped along the 

coastline of Penn 

Cove and the West 

Coastal Strip.

The age of the entire 

unit may be limited 

to between about 

37,000 and 16,800 

years BP by six 

radiocarbon dates 

and the age of the 

West Beach silt. 

However, undated 

strata within the 

unit may include 

significantly older 

deposits.

Deposits of the 

Possession

Glaciation:

Possession Drift

[Qgd(p)]

Glaciomarine drift facies: Highly diverse; typically clayey silt, silty clay, clay, and clayrich diamicton; buff, ranging to ash gray or white; compact and commonly with 

vertical dessication cracks; contains shells; more compact than Everson Interstade 

equivalent; locally indistin-guishable from till. Till facies: Typically sandy diamicton; 

ash gray to white; compact. Outwash sand facies: Gray, medium to fine grained sand. 

Classified as advance. Mostly glaciomarine drift along Blowers Bluff; dominantly sand 

at West Beach and within 2.4 km (1.5 mi) southeast of Ebey’s Landing, but 

glaciomarine drift overlies till farther south along the same bluff. Sand at West Beach 

is very similar to and was distinguished from underlying channel sand of Qc(w) based 

on petrographic determination of mineralogical content. The unit is within vertical 

bluffs along the western shore (West Beach) and at Blowers Bluff.

Variable. The 

glaciomarine 

facies is more 

resistant than

the outwash 

sand facies.

Low. The unit lies

within vertical 

bluffs.

Erosion of the 

unit may 

under-cut the 

bluff and 

influence bluff 

collapse and

retreat.

Shells.

Unlikely (preFraser and 

glacial).

None.

Minor unit mapped 

along the coastline 

of Penn Cove and 

the West Coastal 

Strip.

Type section: 

Possession Point, 

South Whidbey 

Island. 

Distinguished from 

equivalent Fraser 

Glaciation units by 

stratigraphic 

position. Estimated 

age of about 80,000–

60,000 years BP.

Interglacial 

Deposits of the 

Whidbey 

Formation:

Whidbey 

Formation

[Qc(w)]

Sand, silt, clay, peat layers, occasional fine gravel, and rare medium gravel; exposures

commonly weathered to a subtly multicolored to light-yellow hue. Basal flood-plain 

facies overlain by a channel sand facies. Flood-plain facies: Typically 3–6 m (10–20 ft) 

thick, well stratified (subhorizontally), and commonly slightly oxidized. Contains 

discontinuous peat beds. At least 9 m (30 ft) thick along West Beach, but descends 900 

m (3,000 ft) below sea level to the southern flood-plain facies. Channel sand facies: 

Roughly 9 m (30 ft) thick, clean, gray, cross-bedded to massive. Resembles the 

overlying Qgd(p) so that petrographic analysis may be necessary to distinguish these 

two units. At Blowers Bluff, the flood-plain facies reaches a maximum thickness of 8 

m (25 ft) and is overlain by a gravelly, cross-bedded channel sand facies that is 

lavender to light yellowish-gray, 4.5–24 m (15–80 ft) thick, and prone to forming 

angle-of-repose benches at Blowers Bluff and an angle-of-repose cliff at West Beach. 

Local concentrations of dacite and pumice pebble trains come from Glacier Peak 

lahar runout deposits. Age is about 125,000–80,000 years BP.

Low. Forms the

base of the 

section along the

shoreline bluffs 

of West Beach 

and Blowers 

Bluff and thus is 

subject to wave 

and storm 

energy.

Low. The floodplain facies forms 

prominent vertical 

bluffs, which are too 

unstable for 

development. 

Erosion of the 

unit may 

under-cut the 

bluff and 

influence bluff 

collapse and

retreat.

May contain 

pachyderm 

fossils, such as 

the mammoth 

tusk discovered 

in Qc(o).

Unlikely (preFraser and 

glacial).

Sand and peat.

Minor unit mapped 

along the coastline 

of Penn Cove and 

San de Fuca 

Uplands.

Type section: 

Double Bluff, south

Whidbey Island.

Informally named 

the lahar runout of 

Oak Harbor in Oak 

Harbor 7.5-minute 

quadrangle north of 

the reserve. 

Mineralogical 

composition 

indicates an 

ancestral Skagit 

River basin 

provenance. 
* = Landscape Character Areas after Gilbert (1985).

EBLA Geologic Resources Inventory Report 44

Age Map Unit

(Symbol) Geologic Description and Features Erosion Resistance

Suitability for 

Infrastructure Hazards Paleontological Resources

Cultural 

Resources

Mineral 

Occurrence

Major Landscape 

Character Area*

Geological 

Significance

QUATERNARY (Pleistocene)

Deposits of the 

Double Bluff 

Glaciation:

Double Bluff 

Drift

[Qgd(d)]

Glaciomarine drift (silt, clay, and diamicton) and locally underlying till; resembles 

equivalent Vashon Drift units but is assigned to the Double Bluff Glaciation based on 

stratigraphic position; lithology reflects British Columbian provenance. Only mapped 

along 460 m (1,500 ft) of shoreline southeast of Ebey’s Landing. Limited to exposures 

along the shoreline southeast of Ebey’s Landing.

Low. Till facies 

commonly 

resembles 

concrete, but

unit is subject to 

wave and storm 

activity.

Low. Limited 

exposures.

Erosion of the 

unit may 

influence bluff 

collapse.

Unknown.

Unlikely (preFraser and 

glacial).

None.

Minor unit mapped 

along the West 

Coastal Strip.

Type section: 

Double Bluff, south

Whidbey Island. 

About 185,000–

125,000 years BP.

Pre-Fraser 

Nonglacial, 

undivided

(Qc)

Sand, silt, clay, peat, some fine gravel, and rare medium gravel; well stratified to 

massive. Resembles Qc(o) and Qc(w). Thought to be nonglacial but may locally 

include glacial material. Lies below Fraser glacial deposits but otherwise of unknown 

age and association. One exposure is mapped along the north shore of Penn Cove, 

about 900 m (3,000 ft) west of columnar section 4.

Variable 

lithology. 

Subject to wave 

action.

Not applicable. 

Only one exposure. 

Isolated 

exposure, but 

erosion of unit 

may influence 

bluff collapse.

May contain 

pachyderm 

fossils, such as 

the mammoth 

tusk discovered 

in Qc(o).

Unlikely (preFraser and 

glacial).

Sand and peat.

Minor unit mapped 

along Penn Cove 

coastline.

Olympia or 

Whidbey age, but 

older origin is 

possible.

Pleistocene 

deposits, 

undivided

(Qu)

Limited to three isolated exposures on the map. Unknown age and association.

Exposure west of Long Point (columnar section 6) consists of a 22-m (73-ft)- thick 

section of gray, medium- to fine-grained, subangular to sub rounded, poorly sorted, 

compact to mildly compact, plane- to gently cross-bedded, lithologically diverse sand 

with sparsely disseminated, thin [< 1 in. (2.54 cm) thick] elongate pockets of granulesized pumice and coal; soft-sediment deformation structures and/or liquefaction 

features are exposed in the basal 6 m (20 ft) of section 6; sand is interlayered with at 

least three compact, discontinuous, greenish-olive to dark gray diamictons up to 2 m 

(6 ft) thick, with sparse to rare, subrounded to angular granule to pebble clasts. Grains 

angular to subangular. Mixed lithology does not indicate a specific source area or 

glacial or interglacial conditions. Angularity of particles in diamicton suggests till. A

separate exposure 0.5 km (0.3 mi) southwest of the Coupeville dock consists of 

compact, quartz-rich sand. Includes an exposure of somewhat compact cobble gravel 

near the top of a hill 1,200 m (4,000 ft) southeast of Lovejoy Point. Exposure is in the 

sideslope of a hill that rises about 3 m (10 ft) above the surrounding glaciomarine drift 

and recessional outwash gravel, suggesting that the hill is cored with older sediment.

Lower 

resistance to 

erosion along 

Penn Cove 

coastline where

the unit is

subject to wave 

activity

Not applicable. 

Isolated exposures.

Isolated 

exposure, but 

erosion of unit 

along shore 

may influence 

bluff collapse.

May contain 

pachyderm 

fossils, such as 

the mammoth 

tusk discovered 

in Qc(o).

Unlikely (preFraser and 

glacial).

Sand. Minute 

inclusions of 

detrital coal.

Minor unit mapped 

in Coupeville, 

Parker and Pratt 

Wood-lands, and 

Penn Cove.

May include both 

glacial and 

interglacial deposits.

EBLA Geologic Resources Inventory Report 45

Glossary

This glossary contains brief definitions of technical geologic terms used in this report. Not all 

geologic terms used are referenced. For more detailed definitions or to find terms not listed 

here please visit: http://geomaps.wr.usgs.gov/parks/misc/glossarya.html. Definitions are 

based on those in the American Geological Institute Glossary of Geology (fifth edition; 2005).

ablation. All processes by which snow and ice are lost 

from a glacier, including melting, evaporation 

(sublimation), wind erosion, and calving.

ablation till. Loosely consolidated rock debris, formerly 

in or on a glacier, that accumulated in place as the 

surface ice was removed by ablation.

absolute age. The geologic age of a fossil, rock, feature, 

or event in years; commonly refers to radiometrically 

determined ages.

active margin. A tectonically active margin where 

lithospheric plates come together (convergent 

boundary), pull apart (divergent boundary) or slide 

past one another (transform boundary). Typically 

associated with earthquakes and, in the case of 

convergent and divergent boundaries, volcanism. 

Compare to “passive margin.”

alpine glacier. A glacier occurring in a mountainous 

region; also called a valley glacier.

aquifer. A rock or sedimentary unit that is sufficiently 

porous that it has a capacity to hold water, sufficiently 

permeable to allow water to move through it, and 

currently saturated to some level.

asthenosphere. Earth’s relatively weak layer or shell 

below the rigid lithosphere.

beach. A gently sloping shoreline covered with sediment, 

commonly formed by the action of waves and tides.

beach face. The section of the beach exposed to direct 

wave and/or tidal action.

bed. The smallest sedimentary strata unit, commonly 

ranging in thickness from one centimeter to a meter or 

two and distinguishable from beds above and below.

bedding. Depositional layering or stratification of 

sediments.

bedrock. A general term for the rock that underlies soil 

or other unconsolidated, surficial material.

block (fault). A crustal unit bounded by faults, either 

completely or in part.

braided stream. A sediment-clogged stream that forms 

multiple channels which divide and rejoin.

calcareous. Describes rock or sediment that contains the 

mineral calcium carbonate (CaCO3).

cementation. Chemical precipitation of material into 

pores between grains that bind the grains into rock.

chemical sediment. A sediment precipitated directly 

from solution (also called nonclastic).

clast. An individual grain or rock fragment in a 

sedimentary rock, produced by the physical 

disintegration of a larger rock mass.

clastic. Describes rock or sediment made of fragments of 

pre-existing rocks (clasts).

clay. Can be used to refer to clay minerals or as a 

sedimentary fragment size classification (less than 

1/256 mm [0.00015 in]).

claystone. Lithified clay having the texture and 

composition of shale but lacking shale’s fine layering 

and fissility (characteristic splitting into thin layers).

cordillera. A Spanish term for an extensive mountain 

range; used in North America to refer to all of the 

western mountain ranges of the continent.

craton. The relatively old and geologically stable interior 

of a continent (also see “continental shield”).

cross-bedding. Uniform to highly varied sets of inclined 

sedimentary beds deposited by wind or water that 

indicate flow conditions such as water flow direction 

and depth.

crust. Earth’s outermost compositional shell, 10 to 40 km 

(6 to 25 mi) thick, consisting predominantly of 

relatively low-density silicate minerals (also see 

“oceanic crust” and “continental crust”).

deformation. A general term for the process of faulting, 

folding, and shearing of rocks as a result of various 

Earth forces such as compression (pushing together) 

and extension (pulling apart).

delta. A sediment wedge deposited where a stream flows 

into a lake or sea.

diamictite (diamicton). Poorly sorted, noncalcareous, 

sedimentary rock with a wide range of particle sizes.

dip. The angle between a bed or other geologic surface 

and horizontal.

drift. All rock material (clay, silt, sand, gravel, boulders) 

transported by a glacier and deposited directly by or 

from the ice, or by running water emanating from a 

glacier. Includes unstratified material (till) and 

stratified deposits (outwash plains and fluvial 

deposits). Also includes glaciomarine lake and seafloor 

sediments marked by contributions from nearby 

glacial settings (e.g., ice bergs).

dropstone. An oversized stone in laminated sediment 

that depresses the underlying laminae and may be 

covered by other laminae that drape over the stone. 

Most originate through ice-rafting; other sources 

include floating tree roots.

drumlin. A low, smoothly rounded, elongate oval hill, 

mound, or ridge of compact glacial till built under the 

margin of the ice and shaped by its flow with its long 

axis parallel to the direction of ice movement.

dune. A low mound or ridge of sediment, usually sand, 

deposited by wind. 

eolian. Formed, eroded, or deposited by or related to the 

action of the wind. Also spelled “aeolian.”

extrusive. Describes igneous material that has erupted 

onto Earth’s surface.
46 NPS Geologic Resources Division

facies (sedimentary). The depositional or environmental 

conditions reflected in the sedimentary structures, 

textures, mineralogy, fossils, etc. of a sedimentary 

rock.

fault. A break in rock along which relative movement has 

occurred between the two sides.

flame structure. A sedimentary structure consisting of 

wave- or flame-shaped plumes of mud that have been 

squeezed irregularly upward into an overlying layer.

footwall. The mass of rock beneath a fault surface (also 

see “hanging wall”).

formation. Fundamental rock-stratigraphic unit that is 

mappable, lithologically distinct from adjoining strata, 

and has definable upper and lower contacts.

glacial erratic. Boulders transported by glaciers some 

distance from their point of origin.

glaciomarine. The accumulation of glacially eroded, 

terrestrially derived sediment in the marine 

environment.

hanging wall. The mass of rock above a fault surface 

(also see “footwall”).

ice-rafting. The transporting of rock fragments of all 

sizes on or within icebergs, ice floes, or other forms of 

floating ice.

igneous. Refers to a rock or mineral that originated from 

molten material; one of the three main classes of 

rocks—igneous, metamorphic, and sedimentary.

intrusion. A body of igneous rock that invades (pushes 

into) older rock. The invading rock may be a plastic 

solid or magma.

jameo. A large collapse sink formed by collapse of the 

roof of more than one level of a multi-level lava tube 

cave.

kame delta. A flat-topped, steep-sided hill of well-sorted 

sand and gravel deposited by a meltwater stream 

flowing into a proglacial or other ice-marginal lake. 

The proximal margin of the delta was built in contact 

with glacier ice.

lacustrine. Pertaining to, produced by, or inhabiting a 

lake or lakes.

lahar. A mudflow (mass movement) composed primarily 

of volcaniclastic materials on the flank of a volcano. 

The debris carried in the flow includes pyroclasts, 

blocks from primary lava flows, and clastic material.

landslide. Any process or landform resulting from rapid, 

gravity-driven mass movement.

lithification. The conversion of sediment into solid rock.

lithify. To change to stone or to petrify; especially to 

consolidate from a loose sediment to a solid rock 

through compaction and cementation. 

lithosphere. The relatively rigid outmost shell of Earth’s 

structure, 50 to 100 km (31 to 62 miles) thick, that 

encompasses the crust and uppermost mantle.

lodgment till. The plastering beneath a glacier of 

successive layers of basal till commonly characterized 

by compact fissile structure and containing stones 

oriented with their long axes generally parallel to the 

direction of ice movement.

loess. Windblown silt-sized sediment, generally of glacial 

origin.

longshore current. A current parallel to a coastline 

caused by waves approaching the shore at an oblique 

angle.

matrix. The fine grained material between coarse (larger) 

grains in igneous rocks or poorly sorted clastic 

sediments or rocks. Also refers to rock or sediment in 

which a fossil is embedded.

meander. Sinuous lateral curve or bend in a stream 

channel. An entrenched meander is incised, or carved 

downward into the surface of the valley in which a 

meander originally formed. The meander preserves its 

original pattern with little modification.

mechanical weathering. The physical breakup of rocks 

without change in composition. Synonymous with 

“physical weathering.”

member. A lithostratigraphic unit with definable 

contacts; a member subdivides a formation.

meta–. A prefix used with the name of a sedimentary or 

igneous rock, indicating that the rock has been 

metamorphosed.

metamorphic. Describes the process of metamorphism 

or its results. One of the three main classes of rocks—

igneous, metamorphic, and sedimentary.

mineral. A naturally occurring, inorganic crystalline solid 

with a definite chemical composition or compositional 

range.

mud cracks. Cracks formed in clay, silt, or mud by 

shrinkage during dehydration at Earth’s surface.

normal fault. A dip-slip fault in which the hanging wall 

moves down relative to the footwall.

oceanic crust. Earth’s crust formed at spreading ridges 

that underlies the ocean basins. Oceanic crust is 6 to 7 

km (3 to 4 miles) thick and generally of basaltic 

composition.

orogeny. A mountain-building event.

outcrop. Any part of a rock mass or formation that is 

exposed or “crops out” at Earth’s surface.

outwash. Glacial sediment transported and deposited by 

meltwater streams.

paleogeography. The study, description, and 

reconstruction of the physical landscape from past 

geologic periods.

paleosol. A ancient soil layer preserved in the geologic 

record.

passive margin. A margin where no plate-scale tectonism 

is taking place; plates are not converging, diverging, or 

sliding past one another. An example is the east coast 

of North America. (also see “active margin”).

pebble. Generally, small rounded rock particles from 4 

to 64 mm (0.16 to 2.52 in) in diameter.

permeability. A measure of the relative ease with which 

fluids move through the pore spaces of rocks or 

sediments.

plate tectonics. The concept that the lithosphere is 

broken up into a series of rigid plates that move over 

Earth’s surface above a more fluid asthenosphere.

porosity. The proportion of void space (cracks, 

interstices) in a volume of a rock or sediment.

provenance. A place of origin. The area from which the 

constituent materials of a sedimentary rock were 

derived.
EBLA Geologic Resources Inventory Report 47

radioactivity. The spontaneous decay or breakdown of 

unstable atomic nuclei.

radiometric age. An age expressed in years and 

calculated from the quantitative determination of 

radioactive elements and their decay products. 

recharge. Infiltration processes that replenish 

groundwater.

regression. A long-term seaward retreat of the shoreline 

or relative fall of sea level.

relative dating. Determining the chronological 

placement of rocks, events, or fossils with respect to 

the geologic time scale and without reference to their 

numerical age.

reverse fault. A contractional high-angle (greater than 

45°

) dip-slip fault in which the hanging wall moves up 

relative to the footwall (also see “thrust fault”).

ripple marks. The undulating, approximately parallel and 

usually small-scale ridge pattern formed on sediment 

by the flow of wind or water.

sand. A clastic particle smaller than a granule and larger 

than a silt grain, having a diameter in the range of 1/16 

mm (0.0025 in) to 2 mm (0.08 in).

sandstone. Clastic sedimentary rock of predominantly 

sand-sized grains.

sediment. An eroded and deposited, unconsolidated 

accumulation of rock and mineral fragments.

sedimentary rock. A consolidated and lithified rock 

consisting of clastic and/or chemical sediment(s). One 

of the three main classes of rocks—igneous, 

metamorphic, and sedimentary.

shale. A clastic sedimentary rock made of clay-sized 

particles that exhibit parallel splitting properties.

silt. Clastic sedimentary material intermediate in size 

between fine-grained sand and coarse clay (1/256 to 

1/16 mm [0.00015 to 0.002 in]).

siltstone. A variably lithified sedimentary rock composed 

of silt-sized grains.

slump. A generally large, coherent mass movement with a 

concave-up failure surface and subsequent backward 

rotation relative to the slope.

stade. An interval of a glacial stage marked by a 

readvance of glaciers.

strata. Tabular or sheet-like masses or distinct layers of 

rock.

stratigraphy. The geologic study of the origin, 

occurrence, distribution, classification, correlation, 

and age of rock layers, especially sedimentary rocks.

stream. Any body of water moving under gravity flow in 

a clearly confined channel.

strike-slip fault. A fault with measurable offset where the 

relative movement is parallel to the strike of the fault. 

Said to be “sinistral” (left-lateral) if relative motion of 

the block opposite the observer appears to be to the 

left. “Dextral” (right-lateral) describes relative motion 

to the right.

subduction zone. A convergent plate boundary where 

oceanic lithosphere descends beneath a continental or 

oceanic plate and is carried down into the mantle.

tectonic. Relating to large-scale movement and 

deformation of Earth’s crust.

terrane. A large region or group of rocks with similar 

geology, age, or structural style.

terrestrial. Relating to land, Earth, or its inhabitants.

thrust fault. A contractional dip-slip fault with a 

shallowly dipping fault surface (less than 45°

) where 

the hanging wall moves up and over relative to the 

footwall.

till. Unstratified drift, deposited directly by a glacier 

without reworking by meltwater, and consisting of a 

mixture of clay, silt, sand, gravel, and boulders ranging 

widely in size and shape.

topography. The general morphology of Earth’s surface, 

including relief and locations of natural and 

anthropogenic features.

trace (fault). The exposed intersection of a fault with 

Earth’s surface.

transgression. Landward migration of the sea as a result 

of a relative rise in sea level.

transpression. In crustal deformation, an intermediate 

stage between compression and strike-slip motion.

trend. The direction or azimuth of elongation of a linear 

geologic feature.

type locality. The geographic location where a 

stratigraphic unit (or fossil) is well displayed, formally 

defined, and derives its name. The place of original 

description.

unconformity. A substantial break or gap in the geologic 

record where a rock unit is overlain by another that is 

not next in stratigraphic succession.

volcanic. Describes anything related to volcanoes. Can 

refer to igneous rock crystallized at or near Earth’s 

surface (e.g., lava).

volcaniclastic. Pertaining to all clastic volcanic materials 

formed by any process of fragmentation, dispersed by 

any kind of transporting agent, deposited in any 

environment, or mixed in any significant portion with 

nonvolcanic fragments.

water table. The upper surface of the saturated zone; the 

zone of rock in an aquifer saturated with water.

weathering. The physical, chemical, and biological 

processes by which rock is broken down.

EBLA Geologic Resources Inventory Report 49

Literature Cited

This section lists references cited in this report. A more complete geologic bibliography is 

available from the National Park Service Geologic Resources Division.

Atwater, B. F., and E. Hemphill-Haley. 1997. Recurrence 

intervals for great earthquakes of the past 3,500 years 

at northeastern Willapa Bay, Washington. Professional 

Paper 1576. U.S. Geological Survey, Reston, Virginia, 

USA. (http://pubs.usgs.gov/pp/1576/report.pdf). 

Accessed April 10, 2008.

Booth, D.B., J.G. Troost, J.J. Clague, and R.B. Waitt. 2004. 

The Cordilleran Ice Sheet. Pages 17–45 in A.R. 

Gillespie, S.C. Porter, and B.F. Atwater, editors. The 

Quaternary Period in the United States. Elsevier Ltd., 

San Francisco, California, USA.

Burns, R. 1985. The shape and form of Puget Sound. 

Washington Sea Grant Publication, University of 

Washington, Seattle, Washington, USA.

Bush, D. M., and R. Young. 2009. Coastal features and 

processes. Pages 47–67 in R. Young and L. Norby, 

editors. Geological monitoring. Geological Society of 

America, Boulder, Colorado, USA.

(http://nature.nps.gov/geology/monitoring/

coastal.cfm). Accessed September 19, 2011.

Canning, D. 2002. Climate change, climate variability, 

and sea level rise in Puget Sound: Possibilities for the 

future. In T. Droscher, editor. Proceedings of the 2001 

Puget Sound Research Conference, Puget Sound 

Action Team, Olympia, Washington, USA.

Carlstad, C.A. 1992. Late Pleistocene deglaciation history 

at Point Partridge, central Whidbey Island, 

Washington. Thesis. Western Washington University, 

Bellingham, Washington, USA.

Dietrich, W. 2004. Whidbey’s secret: Preserving the 

historic, the rural and the settled, together. The Seattle 

Times: Pacific Northwest Magazine. 

(http://seattletimes.nwsource.com/pacificnw/2004/061

3/cojver.html). Accessed April 10, 2008.

Domack, E.W. 1983. Facies of late Pleistocene glacialmarine sediments on Whidbey Island, Washington--

An isostatic glacial-marine sequence. Pages 535-570 in

B.F. Molnia, editor, Glacial-marine sedimentation. 

Plenum Press, New York, New York, USA.

Dragovich, J.D., G.T. Petro, G.W. Thorsen, S.L. Larson, 

G.R. Foster, and D.K. Norman. 2005. Geologic map of 

the Oak Harbor, Crescent Harbor, and part of the 

Smith Island 7.5-minute quadrangles, Island County, 

Washington. Washington Division of Geology and 

Earth Resources, Geologic Map GM-59 (scale 

1:24,000). (http://www.dnr.wa.gov/Publications/

ger_gm59_geol_map_oakharbor_crescentharbor_24k.

zip). Accessed September 19, 2011.

Easterbrook, D.J. 1994. Chronology of pre-late 

Wisconsin Pleistocene sediments in the Puget 

Lowland, Washington. Pages 191–206 in R. Lasmanis 

and E. S. Cheney, conveners. First symposium on the 

regional geology of Washington State. Washington 

Division of Geology and Earth Resources Bulletin 80, 

Olympia, Washington, USA.

Easterbrook, D.J., D.R. Crandell, and E.B. Leopold. 1967. 

Pre-Olympia Pleistocene stratigraphy and chronology 

in the central Puget Lowland, Washington. Geological 

Society of America Bulletin 78:13–20.

Easterbrook, D.J., K.L. Pierce, J. Gosse, A.R. Gillespie, E. 

Evenson, and K. Hamblin. 2003. Quaternary geology 

of the Western United States. Pages 19–79 in D. J. 

Easterbrook, editor. Quaternary geology of the United 

States. INQUA 2003 Field Guide Volume, XVIINQUA 

Congress. Desert Research Institute, Reno, Nevada, 

USA.

Fay, L.C., J.P. Kenworthy, and V.L. Santucci. 2009. 

Paleontological resource inventory and monitoring: 

North Coast and Cascades Network. Natural 

Resource Technical Report NPS/NRPC/NRTR2009/250. Natural Resource Program Center, National 

Park Service, Fort Collins, Colorado, USA.

Gilbert, C.A. 1985. Ebey’s Landing National Historical 

Reserve: Reading the cultural landscape. National Park 

Service, Pacific Northwest Region, Seattle, 

Washington, (http://www.nps.gov/archive/ebla/

rcl/rcl.htm). Accessed March 28, 2011. 

Gower, H.D. 1980. Bedrock geologic and quaternary 

tectonic map of the Port Townsend area, Washington. 

U.S. Geological Survey, Open-File Report 80–1174 

(scale 1:100,000). (http://ngmdb.usgs.gov/Prodesc/

proddesc_11492.htm). Accessed September 19, 2011.

Hebda, R.J., O. Lian, and S.R. Hicock. 2007. 

Environmental history of the mid Wisconsin Olympia 

Interstadial, Fraser Lowland, British Columbia, 

Canada. Geological Society of America, Abstracts with 

Programs 39(4):17.
50 NPS Geologic Resources Division

Heusser, C.J., and L.E. Heusser. 1981. Palynology and 

paleotemperature analysis of the Whidbey Formation,

Puget Lowland, Washington. Canadian Journal of 

Earth Sciences 18 (1): 136-149.

Johnson, S.Y., S.V. Dadisman, D.C. Mosher, R.J. Blakely, 

and J.R. Childs. 2001. Active tectonics of the Devils 

Mountain fault and related structures, northern Puget 

Lowland and eastern Strait of Juan de Fuca region, 

Pacific Northwest. Professional Paper 1643. U.S. 

Geological Survey, Reston, Virginia, USA. 

(http://pubs.usgs.gov/pp/p1643/). Accessed March 28, 

2011.

Johnson, S.Y., A.R. Nelson, S.F. Personius, R.E. Wells, 

H.M. Kelsey, B.L. Sherrod, K. Okumura, R. Koehler, 

R. Witter, L.A. Bradley, and D.J. Harding. 2003. Maps 

and data from a trench investigation of the Utsalady 

Point Fault, Whidbey Island, Washington. U.S. 

Geological Survey, Miscellaneous Field Studies Map 

MF-2420. (http://pubs.usgs.gov/mf/2003/mf-2420/mf2420-508.pdf). Accessed March 28, 2011. 

Johnson, S.Y., C.J. Potter, J.M. Armentrout, J.J. Miller, 

C.A. Finn, and C.S. Weaver. 1996. The southern 

Whidbey Island fault: An active structure in the Puget 

Lowland, Washington. Geological Society of America, 

Bulletin 108.

Karl, T. R., J. M. Melillo, and T. C. Peterson, editors. 

2009. Global climate change impacts in the United 

States. Cambridge University Press, Cambridge, 

United Kingdom. (http://www.globalchange.gov

/usimpacts). Accessed June 2, 2010.

Kelsey, H.M., B. Sherrod, S.Y. Johnson, and S.V. 

Dadisman. 2004. Land-level changes from a late 

Holocene earthquake in the northern Puget Lowland, 

Washington. Geology 32 (6): 469–472.

Klinger, T., D. Fluharty, C. Byron, K. Evans, and J. Coyle. 

2007. Assessment of coastal water resources and 

watershed conditions at Ebey’s Landing National 

Historical Reserve (Washington). Natural Resource 

Technical Report NPS/NRWRD/NRTR-2007/369. 

Water Resources Division, Natural Resource Program 

Center, National Park Service, Fort Collins, Colorado, 

USA.

Keuler, R.F. 1988. Map showing coastal erosion, 

sediment supply, and longshore transport in the Port 

Townsend 30- by 60-minute quadrangle, Puget Sound 

region, Washington. Miscellaneous Investigation I1198-E. U.S. Geological Survey, Reston, Virginia, USA.

Mustoe, G.E., and C.A. Carlstadt. 1995. A late 

Pleistocene brown bear (Ursus arctos) from northwest 

Washington. Northwest Science 9:106–113.

Mustoe, G.E., C.R. Harington, and R.E. Morlan. 2005. 

Cedar Hollow, an early Holocene faunal site from 

Whidbey Island, Washington. Western North 

American Naturalist 65 (4):429–440.

National Park Service. 2000. Ebey’s Landing National 

Historical Reserve: Administrative history. U.S. 

Department of Interior, Washington, D.C., USA. 

(http://www.nps.gov/archive/ebla/adhi/adhi7.htm). 

Accessed March 28, 2011. 

National Park Service. 2004. The National Parks: Index 

2005–2007. U.S. Department of Interior, Washington, 

D.C., USA.

National Park Service. 2006. Ebey’s Landing National 

Historical Reserve: Final general management plan 

and environmental impact statement. National Park 

Service, Pacific West Region, Seattle, Washington, 

USA. (http://www.nps.gov/ebla/parkmgmt/planning.

htm). Accessed March 28, 2011.

National Park Service. 2008. Central Whidbey Island 

Archaeological Resources. Ebey’s Landing National 

Historical Reserve, Coupeville, Washington, USA. 

(http://www.nps.gov/ebla/arhe/archaeology.htm) 

Accessed January 15, 2008.

National Park Service. 2011. Elwha River restoration. 

(http://www.nps.gov/olym/naturescience/elwhaecosystem-restoration.htm). Accessed June 3, 2011.

National Oceanic and Atmospheric Administration. 

2005. General NOAA Oil Monitoring Environment 

(GNOME). (http://response.restoration.noaa.gov/

software/gnome/gnome.html). Accessed June 7, 2011.

Polenz, M. 2005. A geologic field trip of the Ebey’s 

Landing National Historical Reserve. Unpublished 

report, on file at Ebey’s Landing National Historical 

Reserve. 

Polenz, M., S.L. Slaughter, J.D. Dragovich, and G.W. 

Thorsen. 2005. Geologic map of the Ebey’s Landing 

National Historical Reserve, Island County, 

Washington. Washington Division of Geology and 

Earth Resources, Open-File Report 2005-2 (scale 

1;24,000). (http://wsldocs.sos.wa.gov/library/

docs/dnr/ofr05-2_2006_002116.pdf). Accessed 

September 19, 2011.

Satake, K., K. Shimazaki, Y. Tsuji, and K. Ueda. 1996. 

Time and size of a giant earthquake in Cascadia 

inferred from inferred from Japanese tsunami records 

of January 1700. Nature 379 (6562):246–249.

Satake, K., K. Wang, and B.F. Atwater. 2003. Fault slip 

and seismic moment of the 1700 Cascadia earthquake 

inferred from Japanese tsunami description. Journal of 

Geophysical Research 108 (B11):1–17.

Shipman, H. 2004. Coastal bluffs and sea cliffs on Puget 

Sound, Washington. Professional Paper 1693. U.S. 

Geological Survey, Reston, Virginia, USA. 

(http://www.ecy.wa.gov/pubs/o406029.pdf). Accessed 

June 2, 2011.
EBLA Geologic Resources Inventory Report 51

Troost, K.G. 2002. Summary of the Olympia nonglacial 

interval (MIS 3) in the Puget Lowland, Washington. 

Geological Society of America, Abstracts with 

Programs 34(5):109.

U.S. Geological Survey. 2008. Report: Is Glacier Peak a 

dangerous volcano? USGS Cascades Volcano 

Observatory webpage, Vancouver, Washington, USA. 

(http://vulcan.wr.usge.gov/Volcanoes/GlacierPeak/Ha

zards/OFR95-413/OFR95-413.html). Accessed May 

26, 2011.

Wagner, H.C., and M.C. Wiley. 1980. Preliminary map of 

offshore geology in the Protection Island-Point 

Partridge area, northern Puget Sound, Washington. 

Open-File Report 80-548. U.S. Geological Survey, 

Reston, Virginia, USA. (http://ngmdb.usgs.gov/

Prodesc/proddesc_11690.htm). Accessed September 

19, 2011.

Waitt, R.B., L.G. Mastin, and J.E. Beget. 1995. Volcanichazard zonation for Glacier Peak volcano, 

Washington. Open-file Report 95-499. U.S. Geological 

Survey, Reston, Virginia, USA. (http://vulcan.wr.usgs.

gov/Volcanoes/GlacierPeak/Hazards). Accessed May 

27, 2011.

Walsh, T.J., V.V. Titov, A.J. Venturato, H.O. Mofjeld, 

and F.I. Gonzalez. 2005. Tsunami hazard map of the 

Anacortes-Whidbey Island area, Washington: 

Modeled tsunami inundation from a Cascadia 

Subduction Zone earthquake. Washington 

Department of Natural Resources Open-File Report 

2005-1 (scale 1:62,500).

(http://www.dnr.wa.gov/Publications/ger_ofr2005-

1_tsunami_hazard_anacortes_whidbey.pdf). Accessed 

September 19, 2011.

Washington State Department of Ecology. 2003. 

Admiralty Inlet/Hood Canal: Geographic response 

plan. (http://www.ecy.wa.gov/programs/spills/

preparedness/grp/admiralty%20inlet-hood%20

canal%20pdf/ai-hc%20grp%20intro%203-

03%20f.pdf). Accessed June 7, 2011.

Washington State Department of Natural Resources. 

2010. Geology of Washington: Puget Lowland. 

(http://www.dnr.wa.gov/ResearchScience/Topics/Geo

logyofWashington/Pages/lowland.aspx). Accessed July 

14, 2010.

Wieczorek, G.F., and J.B. Snyder. 2009. Monitoring slope 

movements. Pages 245–271 in R. Young and L. Norby, 

editors. Geological monitoring. Geological Society of 

America, Boulder, Colorado, USA.

(http://nature.nps.gov/geology/monitoring/

slopes.cfm). Accessed September 19, 2011.

EBLA Geologic Resources Inventory Report 53

Additional References

This section lists additional references, resources, and web sites that may be of use to 

resource managers. Web addresses are current as of September 2011.

Geology of National Park Service Areas

National Park Service Geologic Resources Division 

(Lakewood, Colorado). http://nature.nps.gov/geology/

NPS Geologic Resources Inventory. 

http://www.nature.nps.gov/geology/inventory/gre_pu

blications.cfm

Harris, A. G., E. Tuttle, and S. D. Tuttle. 2003. Geology of 

National Parks. Sixth Edition. Kendall/Hunt 

Publishing Co., Dubuque, Iowa, USA.

Kiver, E. P. and D. V. Harris. 1999. Geology of U.S. 

parklands. John Wiley and Sons, Inc., New York, New 

York, USA.

Lillie, R. J. 2005. Parks and Plates: The geology of our 

national parks, monuments, and seashores. W.W. 

Norton and Co., New York, New York, USA.

[Geared for interpreters].

NPS Geoscientist-in-the-parks (GIP) internship and 

guest scientist program. 

http://www.nature.nps.gov/geology/gip/index.cfm

Resource Management/Legislation Documents

NPS 2006 Management Policies (Chapter 4; Natural 

Resource Management): 

http://www.nps.gov/policy/mp/policies.html#_Toc157

232681

NPS-75: Natural Resource Inventory and Monitoring 

Guideline: 

http://www.nature.nps.gov/nps75/nps75.pdf

NPS Natural Resource Management Reference Manual 

#77: http://www.nature.nps.gov/Rm77/

Geologic Monitoring Manual

R. Young and L. Norby, editors. Geological 

Monitoring. Geological Society of America, Boulder, 

Colorado.

http://nature.nps.gov/geology/monitoring/index.cfm

NPS Technical Information Center (Denver, repository 

for technical (TIC) documents): http://etic.nps.gov/

Geological Survey and Society Websites

Washington State Department of Natural Resources. 

http://www.dnr.wa.gov/Pages/default.aspx

U.S. Geological Survey: http://www.usgs.gov/

Geological Society of America: 

http://www.geosociety.org/

American Geological Institute: http://www.agiweb.org/

Association of American State Geologists: 

http://www.stategeologists.org/

Other Geology/Resource Management Tools

Bates, R. L. and J. A. Jackson, editors. American 

Geological Institute dictionary of geological terms (3rd 

Edition). Bantam Doubleday Dell Publishing Group, 

New York.

U.S. Geological Survey National Geologic Map Database 

(NGMDB): http://ngmdb.usgs.gov/

U.S. Geological Survey Geologic Names Lexicon 

(GEOLEX; geologic unit nomenclature and summary): 

http://ngmdb.usgs.gov/Geolex/geolex_home.html

U.S. Geological Survey Geographic Names Information 

System (GNIS; search for place names and geographic 

features, and plot them on topographic maps or aerial 

photos): http://gnis.usgs.gov/

U.S. Geological Survey GeoPDFs (download searchable 

PDFs of any topographic map in the United States): 

http://store.usgs.gov (click on “Map Locator”).

U.S. Geological Survey Publications Warehouse (many 

USGS publications are available online): 

http://pubs.er.usgs.gov

U.S. Geological Survey, description of physiographic 

provinces: http://tapestry.usgs.gov/Default.html
54 NPS Geologic Resources Division

Appendix: Scoping Session Participants

The following is a list of participants from the GRI scoping session for Ebey’s Landing 

National Historical Reserve, held on September 10-12, 2002. The contact information 

and email addresses in this appendix may be outdated; please contact the Geologic 

Resources Division for current information. The scoping meeting summary was used as 

the foundation for this GRI report. The original scoping summary document is available 

on the GRI publications web site: 

http://www.nature.nps.gov/geology/inventory/gre_publications.cfm.

Name Affiliation Position Phone E-mail

Andrascik, Roger NPS – Voyageurs 

National Park Natural Resources 218-283-9821 Roger_Andrascik@nps.gov 

Beavers, Rebecca NPS – Geological 

Resources Division Geologist 303-987-6945 rebecca_beavers@nps.gov 

Connors, Tim NPS - Geological 

Resources Division Geologist 303-969-2093 tim_Connors@nps.gov 

Dalby, Craig NPS - CCSO GIS 206-220-4261 craig_dalby@nps.gov 

Davis, Marsha NPS – Northwest 

Network Geologist Marsha_Davis@nps.gov 

Doyle, Rebecca NPS – Mount Rainier 

National Park Biologist 360-569-2211 rebecca_doyle@nps.gov 

Graham, John Colorado State 

University Geologist

Haugerud, Ralph U.S. Geological 

Survey Geologist 206-553-5542 rhaguerud@usgs.gov 

Heise, Bruce NPS - Geological 

Resources Division Geologist 303-969-2017 Bruce_Heise@nps.gov

Latham, Penny NPS - CCSO PWR IM 206-220-4267 penny_latham@nps.gov 

Norman, Dave WA Department of 

Natural Resources Geologist 360-902-1439 dave.Norman@wadnr.gov 

Pringle, Pat WA Department of 

Natural Resources Geologist 360-902-1433 pat.pringle@wadnr.gov 

Riedel, Jon

NPS – North 

Cascades National 

Park

Geologist 360-873-4590 jon_riedel@nps.gov 

Samora, Barbara NPS – Mount Rainier 

National Park Natural Resources 360-569-2211 barbara_samora@nps.gov 

Swinney, Darin NPS – Mount Rainier 

National Park GIS 360-569-2211 darin_swinney@nps.gov 

Teissere, Ron WA Division of 

Natural Resources Geologist 360-902-1440 ron.teissere@wadnr.gov 
The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides 

scientific and other information about those resources; and honors its special responsibilities to American Indians, 

Alaska Natives, and affiliated Island Communities.

NPS 484/110343, September 2011
National Park Service

U.S. Department of the Interior

Natural Resource Stewardship and Science

1201 Oakridge Drive, Suite 150

Fort Collins, CO 80525

www.nature.nps.gov

EXPERIENCE YOUR AMERICA TM