divided into sub-horizons by the addition of a numerical subscript, based on minor shifts in colour or texture with increasing depth (e.g., B21, B22, B23 etc.). While this can add necessary depth to a field description, workers should bear in mind that excessive division of a soil profile into narrow sub-horizons should be avoided. Walking as little as ten metres in any direction and digging another hole can often reveal a very different profile in regards to the depth and thickness of each horizon. Over-precise description can be a waste of time. In the Australian system, as a rule of thumb, layers thinner than 5 cm (2 inches) or so are best described as pans or segregations within a horizon rather than as a distinct layer. Suffixes describing particular features of a horizon may also be added. The Australian system provides the following suffixes: b: buried horizon. c: presence of mineral concretions or nodules, perhaps of iron, aluminium, or manganese. d: root restricting layer. e: conspicuously bleached. f: faunal accumulations in A horizons. g: gleyed horizon. h: accumulation of organic matter. j: sporadically bleached. k: accumulation of carbonates, commonly calcium carbonate. m: strong cementation or induration. p: disturbed by ploughing or other tillage practices (A horizons only). q: accumulation of secondary silica. r: weathered, digable rock. s: sesquioxide accumulation. t: accumulation of clay minerals. w: weak development. x: fragipan. y: accumulation of calcium sulfate (gypsum). z: accumulation of salts more soluble than calcium sulfate. Buried soils Soil formation is often described as occurring in situ: Rock breaks down, weathers and is mixed with other materials, or loose sediments are transformed by weathering. But the process is often far more complicated. For instance, a fully formed profile may have developed in an area only to be buried by wind- or water-deposited sediments which later formed into another soil profile. This sort of occurrence is most common in coastal areas, and descriptions are modified by numerical prefixes. Thus, a profile containing a buried sequence could be structured O, A1, A2, B2, 2A2, 2B21, 2B22, 2C with the buried profile commencing at 2A2. Horizons and layers according to the USDA Field Book for Describing and Sampling Soils (2012) Source: Master horizons and layers O: Organic soil materials (not limnic). A: Mineral; organic matter (humus) accumulation. E: Mineral; some loss of Fe, Al, clay, or organic matter. B: Subsurface accumulation of clay, Fe, Al,