LOCATION NAPATREE CT+MA RI

Established Series
Rev. DCP-BEF-CEP
02/2025

NAPATREE SERIES

MLRA(s)--144A, 145, 149B
Depth class--Very deep
Drainage class--Subaqueous
Water depth range--2 to 300 centimeters
Parent material--Coarse-loamy estuarine or marine deposits underlain glacial till
Geomorphic location--Submerged headlands, submerged mainland beaches, bay bottoms, and mainland coves within sounds, bays, and estuaries
Slope range for Series--0 to 3 percent
Mean Annual Air Temperature--10 degrees C (50 degrees F)
Mean Annual Precipitation--1295 millimeters (51 inches)

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, nonacid, mesic Haplic Sulfiwassents

TYPICAL PEDON: Napatree gravelly fine sandy loam on a west facing, extremely bouldery, 1 percent slope on a submerged mainland beach adjacent to a submerged headland under 300 centimeters of estuarine water. Tidal range is 220 centimeters. (Colors are for moist soil unless otherwise noted).

Cseg1--0 to 12 centimeters; very dark greenish gray (10Y 3/1) fine sandy loam; massive; nonfluid; slight sulfurous odor; slight effervescence with 30 percent hydrogen peroxide; slightly alkaline (pH 7.7), ultra acid (pH 3.3) oxidized pH; clear boundary.

Cseg2--12 to 28 centimeters; very dark greenish gray (10Y 3/1) fine sandy loam; massive; moderately fluid; 5 percent shell fragments; 5 percent wood fragments; slight sulfurous odor; slight effervescence with 30 percent hydrogen peroxide; slightly alkaline (pH 7.7), ultra acid (pH 3.3) oxidized pH; clear boundary.

Cseg3--28 to 83 centimeters; very dark gray (N 3/) loam; massive; moderately fluid; slight sulfurous odor; slight effervescence with 30 percent hydrogen peroxide; slightly alkaline (pH 7.4), ultra acid (pH 2.4) oxidized pH; clear boundary.

Cseg4--83 to 113 centimeters; very dark greenish gray (10Y 3/1) gravelly coarse sandy loam; massive; nonfluid; 25 percent gravel; 5 percent herbaceous plant fibers; slight sulfurous odor; moderate effervescence to 30 percent hydrogen peroxide; neutral (pH 6.6), ultra acid (pH 2.3) oxidized pH; clear boundary. (Total thickness of Cseg horizons is 0 to 156 centimeters).

2Cseg5--113 to 156 centimeters; very dark gray (5Y 3/1) very gravelly loamy coarse sand; single grain; nonfluid; 45 percent gravel; slight effervescence to 30 percent hydrogen peroxide; neutral (pH 6.7), strongly acid (pH 5.5) oxidized pH; clear boundary.

2Cse1--156 to 175 centimeters; olive brown (2.5Y 4/3) fine sandy loam; massive; nonfluid; many coarse prominent strong brown (7.5YR 4/6) iron masses; many coarse distinct dark gray (5Y 4/1) iron depletions; slight effervescence to 30 percent hydrogen peroxide; slightly acid (pH 6.1), slightly acid (pH 6.3) oxidized pH; clear boundary.

2Cse2--175 to 200 centimeters; olive brown (2.5Y 4/3) gravelly coarse sandy loam; massive; nonfluid; 20 percent gravel; common coarse distinct brown (7.5YR 4/4) iron masses; many coarse prominent dark gray (N 4/) iron depletions; slight effervescence to 30 percent hydrogen peroxide; slightly acid (pH 6.1), moderately acid (pH 5.9) oxidized pH. (Total thickness of 2Cse horizons is 0 to 58 centimeters).

TYPE LOCATION: Fairfield County, Connecticut; north of Greenwich Point, approximately 430 meters (1,410 feet) east of Tod's Driftway road and approximately 995 meters (3,264 feet) south-southwest of the intersection of South Crossway and Shore Road. USGS topographic quadrangle: Stamford, CT

Latitude--41.004666
Longitude-- -73.569695
Datum--WGS84
Coordinates source--from hand-held GPS

RANGE IN CHARACTERISTICS:
Depth to bedrock--Greater than 200 centimeters
Soil moisture--These soils are continuously inundated
Reaction throughout--Slightly acid to moderately alkaline (pH 6.1 to 8.4)
Oxidized reaction--Ultra acid to neutral (pH <3.5 to 7.3)
Electrical Conductivity (EC 1:5 water)--Greater than 0.6 dS/m throughout
Depth to hypersulfidic materials (incubated pH 4.0 after 16 weeks)--0 to 50 centimeters
Total soil organic carbon stock to 100 centimeters--4 to 25 kg m-2
Total soil organic carbon stock to 200 centimeters--7 to 44 kg m-2
Shell fragments--0 to 45 percent, by volume, in some horizons formed in estuarine deposits
Coarse fragments--0 to 70 percent, by volume, in some horizons; below the control section, up to 90% in some horizons formed in glacial till

Ase, Aseg, ACseg, or ACse horizon
Hue--5GY, 5Y, 10Y, 10YR, or N
Value--2.5 through 7
Chroma--0 through 2
Texture--sand, loamy sand, loamy coarse sand, coarse sand, sandy loam, or fine sandy loam with gravelly analogs. Thin horizons of fine sandy loam, loam, or silt loam may be present.
Manner of failure/fluidity class--nonfluid to moderately fluid
Coarse fragments--0 to 35 percent, by volume
Shell fragments--0 to 45 percent, by volume
Plant fibers--0 to 5 percent
Organic carbon density--4 to 31 kg m-3
Redoximorphic features may be present.

C, Cg, or Cseg horizon
Hue--2.5Y, 5Y, or 10Y
Value--3 to 7
Chroma--1 to 4
Texture--sand, loamy sand, loamy fine sand, sandy loam, fine sandy loam, very fine sandy loam, or loam with gravelly analogs
Manner of failure/fluidity class--nonfluid to moderately fluid
Coarse fragments--0 to 50 percent, by volume
Shell fragments--0 to 30 percent, by volume
Organic carbon density--7 to 39 kg m-3

2Cg, 2C, 2Cse or 2Cseg horizon
Hue--10YR, 10Y, 2.5Y, 5Y, 10Y, or 5GY
Value--4 or 5
Chroma--1 to 6
Texture--coarse sand, sand, loamy coarse sand, loamy sand, sandy loam, fine sandy loam, or silt loam with gravelly analogs
Manner of failure/fluidity class--nonfluid
Coarse fragments--0 to 90 percent, by volume
Organic carbon density--1 to 28 kg m-3
Redoximorphic features may be present.

COMPETING SERIES: These are the Fort Neck, Hammock, Marshneck, and Thames soils.
Fort Neck--formed in loamy estuarine deposits underlain by glaciofluvial deposits and found on mainland coves and lagoon bottoms in coastal lagoons and bays
Hammock--formed in marine deposits and found on submerged mainland beaches and bay bottoms in sounds and do not include a lithologic discontinuity with glacial parent materials
Marshneck--formed in loamy estuarine deposits and found on flood-tidal deltas and shoals in coastal lagoons, estuaries, and bays; do not include a lithologic discontinuity
Thames--formed in subaqueous alluvium and found on river channels and shoals in tidal rivers

GEOGRAPHIC SETTING:
Parent material--Coarse-loamy estuarine or marine deposits underlain by glacial till (some areas could have loess deposits over the till)
Landscape-Sounds, bays, and estuaries
Landforms--Submerged headlands, submerged mainland beaches, bouldery bay bottoms, and bouldery mainland coves adjacent to glaciated uplands; surface boulders may be exposed at low tide
Slope--0 to 3 percent
Mean annual precipitation--1023 to 1320 millimeters (40 to 52 inches)
Mean annual air temperature--4 to 13 degrees C (39 to 55 degrees F)
Water salinity range--18 to 30 parts per thousand
Frost-free period--350 to 365 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Anguilla, Billington, Fort Neck, Guilford, Hammock, Niantic, Pishagqua, and Wequetequock soils.
Anguilla--formed in sandy estuarine deposits underlain by sandy and gravelly glaciofluvial deposits and have a sandy family particle size class
Billington--formed in silty estuarine deposits underlain by herbaceous organic material and found on mainland coves
Fort Neck--formed in loamy estuarine deposits underlain by glaciofluvial deposits
Guilford--formed in coarse-silty estuarine deposits
Hammock--formed in marine deposits and found on submerged mainland beaches and bay bottoms in sounds; do not include a lithologic discontinuity with glacial parent materials
Niantic--formed in sandy marine deposits; classify as psammowassents
Pishagqua--formed in silty estuarine deposits
Wequetequock--formed in loamy estuarine deposits underlain by herbaceous organic materials; include an irregular decrease in Holocene-aged carbon with depth

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--Subaqueous
Saturated hydraulic conductivity--High or Very High
Soil moisture regime--Peraquic
Soil is continuously inundated with salt or brackish water.
The potential for submarine fresh ground water discharge zones are high given the geomorphic position and high through very high saturated hydraulic conductivity.

USE AND VEGETATION:
Major uses--These soils are used for recreation and aquatic habitat. Shellfish cultivation, which includes lobsters, hard-clams, and oysters, is very important in these soils. In addition, fishing is commonplace, and the species found in the area include smelt, small cod, flounder, scup, menhaden, and white perch.
Native vegetation--Some areas are vegetated with native floating algae and rooted vegetation such as eelgrass (Zostera marina). Rooted green algae (Codium) also occurs on Napatree soils. Vegetative cover ranges from 0 through 15 percent.

DISTRIBUTION AND EXTENT:
General area--These soils are located along Connecticut, Massachusetts and Rhode Island coasts.
Land Resource Regions--R - Northeastern Forage and Forest Region and S - Northern Atlantic Slope Diversified Farming Region
MLRA(s)--144A, 145, and 149B
Extent--Small

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Special Projects Office

SERIES ESTABLISHED: New London County, Connecticut, 2010.

REMARKS:
Diagnostic horizons and features in this pedon include:
Sulfidic materials--zone from 0 to 113 centimeters (Cseg1, Cseg2, Cseg3, and Cseg4 horizons).
Peraquic moisture regime--positive soil water potential (permanently submerged) at the soil surface. (under 300 centimeters of water at the time of coring).
Particle-size control section--the zone from 0 to 100 centimeters (Cseg1, Cseg2, Cseg3, and part of Cseg4 horizons).
Haplic feature--clay content less than 8 percent from 12 to 28 centimeters (Cseg2 horizon)
Lithologic discontinuity--coarse-loamy estuarine deposits overlying glacial till at 113 centimeters (2Cseg5 horizon).

ADDITIONAL DATA: Type location was taken from S2023CT001065 west of Greenwich Point, CT. Previous type location pedon was 2005CT011003-LN.

Additional support pedons used to develop this series include
2005CT011003-LN, S2009RI009005-QP, S2006RI009012-QP, S2008RI009019-WP, S2008RI009018-WP, S2022CT009018, S2022CT009039, S2022CT011005, S2022CT011010, S2022CT011072, S2022CT011119, S2023CT001064, and 2022CT011044.
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National Cooperative Soil Survey
U.S.A.