Silt In the Unified Soil Classification System (USCS) and the AASHTO Soil Classification system, the sand–silt distinction is made at the 0.075 mm particle size (i.e., material passing the #200 sieve). Silts and clays are distinguished mechanically by their plasticity. Silt is easily transported in water or other liquid and is fine enough to be carried long distances by air in the form of dust. Thick deposits of silty material resulting from deposition by aeolian processes are often called loess. Silt and clay contribute to turbidity in water. Silt is transported by streams or by water currents in the ocean. When
Ardleigh Gravel Pit Ardleigh Gravel Pit Ardleigh Gravel Pit is a 1.2 hectare geological Site of Special Scientific Interest south of Ardleigh in Essex. It is a Geological Conservation Review site. The site exposes a succession of Pleistocene levels, with an interglacial between two glacial periods. The interglacial may date back 700,000 years. The site has plant microfossils rare or unique in Britain, and according to Natural England's description in 1992, it may become the type site for a previously unrecognised British early middle Pleistocene interglacial. The site is divided into two areas. The main one is L-shaped, forming the sloping south-east and