Clay between silts and clays based on the plasticity properties of the soil, as measured by the soils' Atterberg limits. ISO 14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. Mixtures of sand, silt and less than 40% clay are called loam. Loam makes good soil and is used as a building material. Clay minerals typically form over long periods of time as a result of the gradual chemical weathering of rocks, usually silicate-bearing, by low concentrations of carbonic acid and other diluted solvents. These solvents, usually acidic, migrate through the weathering rock after
Paxton (soil) Paxton (soil) The Paxton soil series was established in Worcester County, Massachusetts in 1922, and is named for the town of Paxton where it was first described and mapped. Coarse-loamy, mixed, active, mesic Oxyaquic Dystrudepts. Paxton soils are in the Inceptisol soil order of soil taxonomy. The term "coarse-loamy" indicates that the soil has less than 18% clay and at least 15% or more particles that are fine sand or coarser. The term "mixed" indicates no single mineral is over 40 percent. The term "active" represents a ratio of the cation-exchange capacity to clay of the pedon. The term "mesic"