Green Pond Marsh and 50 percent to 90 percent sand and have loamy sand or sandy loam textures." The work describes hydrologic soil group C as having "moderately high runoff potential when thoroughly wet. Water transmission through the soil is somewhat restricted. Group c soils typically have between 20 percent and 40 percent clay and less than 50 percent sand and have loam, sandy clay loam, clay loam and silty clay loam textures." Green Pond Marsh is in a section of Northampton County with karst geological features. Karst geology manifests itself on topographic maps with closed, semi-closed, or linear depressions. The depressions are
Geology of Great Britain is a varied distribution of unconsolidated material of more recent origin. It includes material deposited by glaciers (boulder clay, and other forms of glacial drift such as sand and gravel). "Drift" geology is often more important than "solid" geology when considering building works, drainage, siting water boreholes, sand and gravel resources and soil fertility. Although "drift" strictly refers to glacial and fluvio-glacial deposits, the term on geological maps has traditionally included other material including alluvium, river terraces, etc. Recent maps use the terms "bedrock" and "superficial" in place of "solid" and "drift". This description of the geological history of Great