The following is a map unit description from the "Soil Survey of Norfolk and Suffolk Counties, Massachusetts (Peragallo, 1989)"
HrD-Hollis-Rock outcrop-Charlton complex, 15 to 35 percent slopes. This map unit consists of moderately steep soils and areas of exposed bedrock on hills and ridges where relief is controlled by the underlying bedrock. In a typical area it is about 30 percent Hollis soil, 30 percent Rock outcrop, 25 percent Charlton soil. and 15 percent other soils. The soils and areas of exposed bedrock in this complex are intermingled so closely that it was not practical to separate them in mapping at the scale used for mapping. The shallow, somewhat excessively drained Hollis soil is on the tops of ridges or is near rock outcrops. The very deep, well drained Charlton soil is on side slopes and foot slopes. Stones and boulders 10 inches to 10 feet in diameter cover 0 to 15 percent of the surface, Areas are irregular in shape and range from 6 to 150 acres.
Typically, the surface layer of the Hollis soil is black fine sandy loam about 2 inches thick. The subsoil is dark yellowish brown fine sandy loam about 11 inches thick. Bedrock is at a depth of 14 inches. In some areas the substratum is pale yellow fine sandy loam. The bedrock is granite, basalt, diorite, or conglomerate.
Typically, the surface layer of the Charlton soil is black fine sandy loam about 1 inch thick. The subsurface layer is dark brown fine sandy loam about 5 inches thick. The subsoil is yellowish brown fine sandy loam about 30 inches thick. The substratum is light brownish gray sandy loam to a depth of 60 inches or more. In some areas the surface layer is very fine sandy loam. In some areas the subsoil is redder.
Included with this complex in mapping are small areas of moderately deep soils and areas of Canton soils on side slopes. Also included are small areas of seeps or wet pockets. Stones and boulders cover 1 to 15 percent of the surface. Included areas make up about 10 percent of the map unit.
Permeability: Moderate or moderately rapid throughout in both Hollis and Charlton soils.
Available water capacity: Hollis soil-low; Charlton soil-moderate.
Soil reaction: Hollis soil-very strongly acid or strongly acid; Charlton soil-very strongly acid to moderately acid.
Depth to bedrock: Hollis soil-10 to 20 inches: Charlton soil-more than 60 inches.
Depth to the seasonal high water table: More than 6 feet in both Hollis and Charlton soils.
Hydrologic group: Hollis-C/D; Charlton-B.
Most of the soils in this complex are woodland. A few small areas are used as individual homesites.
This map unit is generally not suited to cultivated crops and pasture because of slope and, on the Hollis soil, shallow depth to bedrock.
Potential productivity for northern red oak on these soils is moderate. Management concerns are slope and, on the Hollis soil, shallow depth to bedrock and low available water capacity. Rock outcrops restrict the use of equipment. Some areas are suitable for handplanting of trees.
Slope is the main limitation to use of these soils as building sites. In addition, on the Hollis soil, shallow depth to bedrock is also a limitation. Extensive land shaping and blasting of bedrock are generally necessary. Constructing roads on the contour, if possible, and planting roadbanks to well adapted grasses help to control erosion. In some areas the underlying bedrock limits road construction, The underlying bedrock and slope are the main limitations to use of these soils as sites for septic tank absorption fields. Installing the distribution lines across the slope is generally needed for proper operation. In many areas bedrock limits installation operations.
The Hollis and Charlton soils are in capability subclass VIIs.
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