Soil mechanics necessary to run water through the sieves to wash the coarse particles and clods through. A variety of sieve sizes are available. The boundary between sand and silt is arbitrary. According to the Unified Soil Classification System, a #4 sieve (4 openings per inch) having 4.75mm opening size separates sand from gravel and a #200 sieve with an 0.075 mm opening separates sand from silt and clay. According to the British standard, 0.063 mm is the boundary between sand and silt, and 2 mm is the boundary between sand and gravel. The classification of fine-grained soils, i.e., soils that are
Campden Tunnel Gravel Pit 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 water is considered to have run from the ice-filled valley of the River Avon (north) to the drainage system of the River Evenlode (south east). This links with the sequence of glacial deposits in the