~ C)

9 0 1,11

C)

STATE OF WASHINGTON

DEPARTMENT OF NATURAL RESOURCES

BERT L COLE, Commissioner of Public Lands

DON LEE FRASER, Supervisor

==========================

DIVISION OF GEOLOGY AND EARTH RESOURCES

VAUGHN E. LIVINGSTON, JR., State Geologist

GEOLOGIC MAP GM-14

PRELIMINARY SURFICIAL GEOLOGIC MAP OF THE

EDMONDS EAST AND EDMONDS WEST QUADRANGLES,

SNOHOMISH AND KING COUNTIES, WASHINGTON

By

MACKEY SMITH

Prepared in cooperation with

UNITED STATES GEOLOGICAL SURVEY

WASHINGTON DEPARTMENT OF NATURAL RESOURCES DIVISION OF GEOLOGY AND EARTH RESOURCES

PRELIMINARY SURFICIAL GEOLOGIC MAP

of the

EDMONDS EAST and EDMONDS WEST QUADRANGLES,

w z w

g 0 :c

w z w u

~ w ..'.

SNOHOMISH and KING COUNTIES, WASHINGTON

Artificiol fill

Peet

Accumulations of organic material. lvloy contain small amounts of sand, silt, cloy, and volcanic ash deposited in swamps and bogs.

Old landslides

Lorge slumps that occurred during the ablotion of the Pugel lobe of the Vashon ice ·sheet by lowering of water-table level, Slides may hove been active since original movement; lacks evidence of recent movement.

EJ Vashon recessional outwosh

Light- brown loosely compacted sand and grovel. Dry grovel seeks ang le of repose of 35°; wet grovel will stand in near- vertical cliff. Sorting varies; particle size varies from medium sand to cobbles. Stones ore usually covered With o light-brown dusty coating and ore well rounded from stream tronsportotion. Contains some ice contact deposits.

Vashon till

Poorly sorted, nonstratified lodgment till deposited as ground moraine. Mixture of cloy, silt, sand, peb­bles, and cobbles with occasional large boulders . Appears gray to blue on fresh surface; may weather to brown or yellow. Extremelr compact, will stand in near-vertical clifk; genera ly locks surficiol crocks or ioints . Stones ore subongulor to rounded. Some larger closts show striations ond faceting, Vertical faces sometimes spoil off in large blocks. Some areas of Ovt are covered by a thin veneer of loosely consolidated, nonsorted oblation till ond(or) thin outwosh.

Vashon advance outwosh

Fresh , light- gray, stratified, compact sand and grovel. Will stand in near-vertical cliff. Sorting varies; particle si:te varies from fine sand to coarse pebbles.

Esperance Sand •

Thinly bedded (from 2 to 6 inches) , fresh, light- gray sand layers. Particle si:ie varies from medium to coarse sand {with 10 percent pebbles); small peb­bles often occupy the base of each individual bed or lens. Occosionol lenses of coarse grovel occur. Usually sloughs to angle of repose on exposed slopes.

Whidbey Formation

Generolly medium - bedded (2 to 4 feet) sond, silt, and cloy, Color vories from light brown to gray. Par­ticle si:ie varies from cloy to coarse sand with o few lenses of small pebbles. Sort ing is genero!ly good within each individua l bed. Cloy ond silt beds con be os thin as 2 inches. Nonglociol river flood-plain deposits. Moy show tectonic deforma­tion.

Double Bluff Drift

Contains: {1) iron- oxide cemented grovel, consisting of small to medium pebbles well cemented in o grit matrix; (2) pebbly glociolacustrine silts; ond (3) massive silt ond lesser beds of sand and grovel. Well compacted and will stand in a near-vertical cliff. Pebbly silts display desiccation crocks at the surface. Moy show tectonic deformotion.

By Mackey Smith

1975

EXPLANATION

Alluvium

Mostly sand ond grovel deposited by streoms. Moy con­tain some silt, cloy, and organic moterio!.

z 0 w

C

< ~ ~ z ~

(.') 0 :c

"' "' w j V)

<(

"' ...

Clay of unknown~

Mocliried land

Original topog raphy distu rbed by removal of some Pleistocene deposits, grading, and a rtificial fill of unknown quality.

Landslides

Deposits of octive slumps, slides, ond oreos of Flowoge. Moy include some deposits of old landslides. Shows evidence of recent movement.

Point

Geology by Mackey Smith 197.4

Bose map from U. S. Geolog ical Survey

Edmonds East a nd Edmonds West ,., . 7n minute Quadrangles

• • ~

•

Compact si lt ond cloy, beds vary from 2 inches to mas­sive in thickness.

* SCALE 1:2.4,000

0 1 MILE

' .. . .

PREPARED IN COOPERATION WITH THE U.S. GEOLOGICAL SURVEY

' '

' . ' . . ',

LAKE

WASHINGTON

lnalewood Count,~ C!u

ml

l 22'15' 47•52.30 .. GEOLOGIC MAP

r

T. 27 N

r. 26 N

47"45' 122·15·

GM-14