Uniformitarianism

Is a theory that rejects the idea that catastrophic forces were responsible for the current conditions on the Earth. The theory suggested instead, that continuing uniformity of existing processes were responsible for the present and past conditions of this planet. United States Natural Resources Conservation Service Soil Classification System A hierarchical system that is used in United States to classifiy soils. This system has six levels: order, suborder, great group, subgroup, family, and series. At the order level, 12 types of soils are recognized: gelisols, oxisols, aridsols, mollisols, alfisols, ultisols, spodsols, entisols, inceptisols, vertisols, histosols, and andisols.