The following is a map unit description from the "Soil Survey of Barnstable County, Massachusetts (Fletcher, 1993)"
PyD-Plymouth-Barnstable-Nantucket complex, hilly, very bouldery. These hilly and steep, very deep, excessively drained and well drained soils are on hills and ridges on moraines. Stones and boulders cover 1 to 3 percent of the surface. Slopes range from 15 to 35 percent. The soils make up about 0.8 percent (2,168 acres) of the survey area. They are mapped mainly in the Plymouth-Barnstable-Nantucket general soil map unit. Areas are irregular in shape and generally range from 20 to 300 acres in size. They are about 40 percent Plymouth soil, 20 percent Barnstable soil, 15 percent Nantucket soil, and 25 percent other soils. The soils occur as areas so intricately mixed or so small that separating them in mapping is not practical.
Typically, the surface of the Plymouth soil is covered with an organic layer. This layer is about 1 inch of loose, undecomposed pine needles, leaves, and twigs and 1 inch of partly decomposed and well decomposed organic material. The surface layer is about 3 inches thick. It is black, very friable loamy coarse sand in the upper 1 inch and gray, loose coarse sand in the lower 2 inches. The subsoil is about 26 inches thick. In sequence downward, it is 1 inch of dark brown, very friable gravelly loamy coarse sand; 5 inches of strong brown, very friable gravelly loamy coarse sand; 1 0 inches of yellowish brown, very friable gravelly loamy coarse sand; and 10 inches of light yellowish brown, loose gravelly coarse sand. The substratum extends to a depth of 65 inches or more. It is light brownish gray, loose gravelly coarse sand in the upper 12 inches and pale brown, loose coarse sand in the lower part.
Typically, the surface of the Nantucket soil is covered with an organic layer. This layer is about 1.5 inches of undecomposed leaves and twigs and 0.5 inch of partly decomposed and well decomposed organic material. The surface layer is sandy loam about 5 inches thick. It is very dark grayish brown and very friable in the upper 1 inch and dark yellowish brown and friable in the lower 4 inches. The subsoil is friable sandy loam about 22 inches thick. The upper 12 inches is yellowish brown, and the lower 1 0 inches is light olive brown. The substratum to a depth of 65 inches is light olive brown, firm loam. Below a depth of 65 inches, it may have layers of loose gravel and sand.
Included with these soils in mapping are small areas of Carver and Hinckley soils and small areas where slopes are less than 15 percent. Also included are small, isolated areas where the soils have no boulders on the surface. Included soils make up about 25 percent of this unit.
Permeability is rapid in the subsoil of the Plymouth soil and very rapid in the substratum. Available water capacity is low. Depth to the seasonal high water table is more than 6 feet.
Permeability is moderately rapid in the subsoil of the Barnstable soil and rapid or very rapid in the substratum. Available water capacity is moderate. Depth to the seasonal high water table is more than 6 feet.
Permeability is moderately rapid in the subsoil of the Nantucket soil and moderately slow or slow in the substratum. Available water capacity is moderate. Depth to the seasonal high water table generally is more than 6 feet. In some areas, however, a perched wat6r table is at a depth of 2.0 to 2.5 feet in early spring.
Most areas are used as woodland. These soils are unsuitable as cropland because the surface stones and boulders restrict the use of equipment. The Barnstable and Nantucket soils are suited to cultivated crops, however, if the surface stones and boulders are removed. Erosion is a hazard because of the slope. The Plymouth soil is droughty during periods of low rainfall.
These soils are poorly suited to hay and pasture because of the slope and the surface stones and boulders. The main management objective is the prevention of overgrazing, which reduces the hardiness and density of desirable plants. Proper stocking rates, timely grazing, and restricted use during wet periods help to maintain plant density and minimize surface compaction.
These soils are poorly suited to woodland. The use of equipment is restricted because of the slope and the surface boulders. The Plymouth soil is droughty. As a result, some seedling loss is expected. Thinning dense stands to standard stocking levels results in more vigorous tree growth. Removal or control of competing vegetation helps to obtain the best growth of newly established seedlings. The most common trees are pitch pine, white oak, scarlet oak, eastern white pine, and black oak.
The slope is the main limitation if these soils are used as sites for buildings. Extensive land shaping is generally needed. Buildings and lots should be designed so that they conform to the natural slope of the land. Erosion is a severe hazard during and after construction. Planting well suited grasses as soon as possible after the surface is disturbed minimizes the erosion hazard. The surface and subsurface stones and boulders may interfere with site development.
These soils are limited as sites for septic tank absorption fields. The Barnstable and Plymouth soils may not adequately filter the effluent, and the Nantucket soil does not readily absorb the effluent. The pollution of ground water is a hazard in areas of the Barnstable and Plymouth soils, and seepage is a hazard in areas of the Nantucket soil. The slope is an additional limitation. Onsite investigation is needed to determine the suitability of a given area and the measures needed to overcome the limitations.