Unified Soil Classification System group symbol. For example, GW-GM corresponds to "well-graded gravel "with silt"." If the soil has more than 15% by weight retained on a #4 sieve (R > 15%), there is a significant amount of gravel, and the suffix "with gravel" may be added to the group name, but the group symbol does not change. For example, SP-SM could refer to "poorly graded SAND with silt" or "poorly graded SAND with silt and gravel." Unified Soil Classification System The Unified Soil Classification System (USCS) is a soil classification system used in engineering and geology to describe the texture and grain size
Eye Gravel Pit Eye Gravel Pit Eye Gravel Pit is a 0.4 hectare geological Site of Special Scientific Interest in Eye Green in Cambridgeshire. It is a Geological Conservation Review site, and part of it overlaps Eye Green Local Nature Reserve. This former gravel quarry in the East Anglian Fens has marine and a few non-marine shells laid down when the area was under the North Sea, probably during the warm Eemian period, 130,000 to 115,000 years ago. It is described by Natural England as important because it lies at the junction between fluvial and glacial deposits. The site is private land with