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
Campden Tunnel Gravel Pit Midlands and the Upper Thames terraces (Evenlode Valley). The site also links with others in the Moreton-in-Marsh area, for example Stretton-on-Fosse. The site is considered precious so it must only be used for research purposes. Campden Tunnel Gravel Pit Campden Tunnel Gravel Pit () is a geological Site of Special Scientific Interest in Gloucestershire, notified in 1988. The site is listed in the 'Cotswold District' Local Plan 2001-2011 (on line). The site exposes a mixture of gravels, sands and silts which make up the Campden Tunnel Drift (Pleistocene period). These are glacial sediments which fill a deep channel. The melt