LOCATION COWDREY CO+ID WY
Established Series
Rev. AJC/GB/CR
10/2026
COWDREY SERIES
The Cowdrey series consists of very deep, well drained soils formed in colluvium from glacial till, glacial drift, or igneous, metamorphic, or sedimentary rock. These soils are on mountain slopes, ridges, fans, toes, landslides, and old glacial plains. Slopes are 2 to 65 percent. The mean annual precipitation is about 575 mm and the mean annual temperature is about 3.0 degrees C.
TAXONOMIC CLASS: Fine, smectitic Eutric Glossocryalfs
TYPICAL PEDON: Cowdrey clay loam in forestland. (Colors are for dry soil unless otherwise noted.)
Oi--0 to 8 cm; slightly decomposed organic material, mainly needles, bark, and twigs.
Oe--8 to 10 cm; partially decomposed organic material.
A--10 to 18 cm; very dark gray (10YR 3/1) clay loam, black (10YR 2/1) moist; strong fine granular structure; soft, very friable, 5 percent gravel and cobble[RC-NIFI1.1]; neutral (pH 6.6); abrupt wavy boundary.
E--18 to 30 cm; light gray (10YR 7/2) clay loam, grayish brown (10YR 5/2) moist; moderate medium platy structure parting to strong fine granular; soft, very friable; 10 percent gravel and cobbles; slightly acid (pH 6.2); gradual wavy boundary.
E/B--30 to 40 cm; mixed[RC-NIFI2.1] light gray (10YR 7/2) and brown (10YR 5/3) clay loam, mixed grayish brown (10YR 5/2) and brown (10YR 4/3) moist; strong fine angular blocky structure; very hard, very friable; few continuous distinct clay films on ped faces; slightly acid (pH 6.4); clear smooth boundary.
Bt1--40 to 71 cm; brown (10YR 5/3) clay, brown (10YR 4/3) strong medium angular blocky structure; extremely hard, friable, very plastic; continuous clay films on rock fragments; 14 percent gravel; neutral (pH 6.6); gradual wavy boundary.
Bt2--71 to 86 cm; light olive brown (2.5Y 5/4) gravelly clay, olive brown (2.5Y 4/4) moist; weak medium angular blocky structure; very hard, firm, very plastic; extremely hard; many discontinuous distinct clay films on faces of peds; few discontinuous faint clay films on surfaces along root channels and on rock fragments; 25 percent gravel; neutral (pH 6.8); diffuse wavy boundary.
C--86 to 163 cm; light olive gray (5Y 6/2) clay, olive gray (5Y 5/2) moist; massive; extremely hard, very plastic; 14 percent gravel and cobble; neutral (ph 7.0).
TYPE LOCATION: Jackson County, Colorado; 740 feet south of the center of Sec. 24, T. 7 N., R. 77 W.[RC-NIFI3.1]
RANGE IN CHARACTERISTICS: [RC-NIFI4.1]
Mean annual soil temperature--0.0 to 7.8 degrees C
Depth to argillic-- 34 to 58 cm
Particle-size control section (weighted averages)
Clay content--40 to 45 percent
Total rock fragments--10 to 35 percent
Oi or Oe
Texture--slightly or moderately decomposed plant material
Reaction--pH 4.0 to 6.0
Organic matter content--55 to 95 percent
Thickness--2 to 10 cm
A horizons
Hue--7.5YR or 10YR, dry or moist
Value--2 or 2.5 moist
Chroma--1 or 2 moist
Texture (less than 2 mm fraction)--clay loam, loam, fine sandy loam
Clay content--10 to 40 percent
Rock fragments--3 to 14 percent gravel
Reaction--pH 5.1 to 6.5
Thickness--0 to 4 cm
E horizons
Hue--5Y to 7.5YR, dry or moist
Value--4 or 5 moist
Chroma--2 to 7 dry, 3 to 6 moist
Texture (less than 2 mm fraction)--clay loam, sandy loam, fine sandy loam, very fine sandy loam
Clay content--11 to 19 percent
Rock fragments--5 to 14 percent gravel
Reaction--pH 5.1 to 7.3
Thickness--8 to 28 cm
E/B horizon (when present)
E parts
Value--2 or 3 moist
Clay content--35 to 39 percent
Rock fragments--5 to 12 percent gravel
Reaction--pH 5.1 to 6.6
Thickness--10 to 18 cm
Bt horizons
Hue--5Y to 7.5YR dry, 5Y to 7.5YR moist
Value--5 or 6 dry, 4 or 5 moist
Chroma--2 to 8, dry or moist
Texture (less than 2 mm fraction)--clay loam, clay, silty clay loam
Clay content--35 to 50 percent
Rock fragments--18 to 25 percent - 5 to 25 percent gravel, 0 to 20 percent cobble
Reaction--pH 5.3 to 7.3
Thickness--43 to 76 cm
C horizon (when present)
Hue--5Y to 7.5YR, dry or moist
Value--6 or 7 dry, 4 or 5 moist
Chroma--2 to 4, dry or moist
Texture (less than 2 mm fraction)--clay loam, sandy loam
Clay content--5 to 38 percent
Rock fragments--10 to 58 percent - 10 to 58 percent gravel, 0 to 1 percent cobble
Reaction--pH 6.1 to 7.3
COMPETING SERIES:
Gateway (CO)--soils are moderately deep to paralithic contact
Muggins (CO)--soils have 5YR or redder hues in Bt horizon
Stovho (SD)--soils have less than 15 percent fine and coarser sand
GEOGRAPHIC SETTING:
Landform--mountain slopes, ridges, fans, toes, landslides, and old glacial plains
Elevation--2,130 to 3,600 meters
Slope--2 to 65 percent
Parent material--colluvium from glacial till, glacial drift, or igneous, metamorphic, or sedimentary rock
Climate--long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation--400 mm to 850 mm
Mean annual air temperature--0 to 5.0 degrees C
Frost-free period--20 to 70 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained, 0.5 TO 50 um/sec in upper mineral horizons, 1.5 to 100 um/sec in the C horizon.
USE AND VEGETATION: Cowdrey soils are primarily used for grazing, timber and recreation. The potential native vegetation is Douglas-fir, subalpine fir, huckleberry, heartleaf arnica, and Geyer's sedge.
DISTRIBUTION AND EXTENT: Cowdrey soils are of moderate extent in Colorado, Wyoming, and southeastern Idaho; MLRAs 48A and 43B.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Star Valley Area, Idaho and Wyoming; 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon
Glossic horizon--
Argillic horizon--40 to 86 cm (Bt1 and Bt2 horizon)
Paricle-size control section--40 to 86 cm
Cowdrey soils have a cryic temperature regime and an udic moisture regime.
2/2004 The concept of the series was narrowed to typic-udic moisture to match the type location and most areas where this series is mapped. Therefore, the classification was changed from Ustic to Eutric Glossocryalf.
Taxonomic Version: Twelfth Edition, 2014
National Cooperative Soil Survey
U.S.A.