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
Sand whole numbers. The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica (silicon dioxide, or SiO), usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is the most common mineral resistant to weathering. The composition of mineral sand is highly variable, depending on the local rock sources and conditions. The bright white sands found in tropical and subtropical coastal settings are eroded limestone and may contain coral and shell fragments in addition to other organic or organically derived fragmental material, suggesting sand formation depends on living organisms, too.