LOCATION SEQUIM WAEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Vitrandic Haploxerolls
TYPICAL PEDON: Sequim very gravelly ashy sandy loam, pasture. (Colors are for moist soil unless otherwise noted. All texture are apparent field textures.)
Ap--0 to 10 inches; very dark brown (10YR 2/2) very gravelly ashy sandy loam, very dark grayish brown (10YR 3/2) dry; weak fine and very fine granular structure; slightly hard, very friable, slightly sticky, nonplastic; many fine and very fine roots; many fine and very fine tubular and irregular pores; 30 percent pebbles and 10 percent cobbles; neutral (pH 6.6); clear smooth boundary. (7 to 10 inches thick)
2AC--10 to 23 inches; dark brown (10YR 3/3) extremely cobbly loamy sand, brown (10YR 5/3) dry; single grained; loose; many fine and very fine roots; many fine and very fine irregular pores; 40 percent pebbles and 30 percent cobbles; neutral (pH 6.6); gradual smooth boundary. (8 to 13 inches thick)
2C1--23 to 36 inches; brown (10YR 4/3) extremely cobbly sand, pale brown (10YR 6/3) dry; single grained; loose; many fine and very fine roots; many fine and very fine irregular pores; 40 percent pebbles and 30 percent cobbles; neutral (pH 6.8); clear smooth boundary. (10 to 13 inches thick)
2C2--36 to 60 inches; dark grayish brown (2.5Y 4/2) extremely cobbly sand, light brownish gray (2.5Y 6/2) dry; single grained; loose; few very fine roots; many fine and very fine irregular pores; 40 percent pebbles and 30 percent cobbles; neutral (pH 6.8).
TYPE LOCATION: Clallam County, Washington; 1,300 feet west and 800 feet north of the SE corner of section 18, T.30N., R.3W.
RANGE IN CHARACTERISTICS: These soils are usually moist but are dry in the moisture control section for 75 to 90 consecutive days following summer solstice. The particle size control section is 60 to 80 percent pebbles and cobbles. The mean annual soil temperature is estimated to range form 50 to 53 degrees F. The mollic epipedon is 15 to 23 inches thick.
The A horizon has value of 2 or 3 moist and 3 or 4 dry. This horizon has granular or subangular blocky structure. It is slightly acid or neutral.
The 2AC horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 through 6 dry, and chroma of 3 or 4. It is very gravelly loamy sand, very cobbly loamy sand, or extremely cobbly loamy sand. It is slightly acid or neutral.
The 2C horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 2 or 3. It is very gravelly loamy sand, extremely gravelly loamy sand, extremely cobbly loamy sand, very gravelly sand, extremely gravelly sand or extremely cobbly sand.
COMPETING SERIES: These are the Alecanyon, Leiko and Owhi series. Alecanyon and Owhi soils are east of the Cascade Mountains and are dry for 90 to 105 consecutive days. Leiko and Owhi soils are east of the Cascade Mountains and have a 7 to 14 inch thick mollic epipedon.
GEOGRAPHIC SETTING: Sequim soils are on river terraces and alluvial fans at elevations of 20 to 300 feet. They formed in old alluvium. The soils are in a mild marine climate and have cool, dry summers and cool, moist winters. The mean annual precipitation is 16 to 22 inches. The average January temperature is about 38 degrees F.; the average July temperature is about 60 degrees F.; and the mean annual temperature is about 49 degrees F. The frost free season is 170 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carlsborg, Clallam, Dungeness, Hoypus, and Yeary soils. Carlsborg soils lack a mollic epipedon. Clallam soils are loamy-skeletal and have a densic contact at a depth of 20 to 40 inches. Dungeness soils are coarse-silty. Hoypus soils lack a mollic epipedon. Yeary soils are fine-loamy and have a densic contact at a depth of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow runoff; rapid permeability.
USE AND VEGETATION: Homesites and irrigated cropland are the principal uses. Native vegetation is Oregon grape, blackberry, brachenfern, salal and annual and perennial grasses. Principal crops are alfalfa and grass hay, strawberries and pasture.
DISTRIBUTION AND EXTENT: Eastern Clallam County, Washington; MLRA 2. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Clallam County, Washington, 1937.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy.