The following is a map unit description from the "Soil Survey of Norfolk and Suffolk Counties, Massachusetts (Peragallo, 1989)"
RoD-Rock outcrop-Hollis complex, 3 to 25 percent slopes. This map unit consists of areas of exposed bedrock and nearly level to steep, shallow, somewhat excessively drained Hollis soil (fig. 9). It is on tops and along ridge lines of steep upland hills and in coastal areas along Boston Bay. In a typical area it is about 55 percent Rock outcrop, 40 percent Hollis soil, and 5 percent other soils. The areas of exposed bedrock and the Hollis soil in this map unit are intermingled so closely that it was not practical to separate them at the scale used for mapping. Areas of the map unit are long and narrow or irregular in shape and range from 5 to 200 acres.
Typically, the surface layer of the Hollis soil is black fine sandy loam about 3 inches thick. The subsoil is dark yellowish brown fine sandy loam about 11 inches thick. Bedrock is at a depth of about 14 inches. In some areas the substratum is yellowish brown fine sandy loam. The bedrock is granite, basalt, diorite, or conglomerate.
Included with this unit in mapping are small areas of moderately deep, well drained soils on foot slopes and very poorly drained Whitman and Swansea soils in depressions. In some areas slopes range to as much as 45 percent. Included areas make up about 10 percent of the map unit.
Permeability: Moderate or moderately rapid throughout.
Available water capacity: Low.
Soil reaction.- Strongly acid or moderately acid.
Depth to bedrock.- 1 0 to 20 inches.
Depth to the seasonal high water table.- More than 6 feet.
Hydrologic group: C/D.
Most areas of the Hollis soil are woodland. Many areas are used as parks and reservations. A few areas are used for radio, TV, or microwave transmission towers.
Extensive exposures of bedrock and the shallow Hollis soil of this map unit are generally not suitable to most uses. It is best suited to use as habitat for woodland wildlife and to recreational use such as hiking.
Potential productivity for northern red oak on this soil is moderate. Management concerns are shallow depth to bedrock and low available water capacity. Bedrock outcrops restrict the use of equipment. Some areas are suitable for hand-planting of trees.
The Hollis soil is generally not suitable for building site development and for use as sites for septic tank absorption fields. Areas that are better suited to these uses are generally nearby.
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