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
Gravel Run (Susquehanna River tributary) the United States Geological Survey quadrangle of Riverside. The stream is one of the main streams in Northumberland County. Gravel Run has been contained in Northumberland County since the county was formed in 1772, when Pennsylvania was still a colony. At the time, it was located in Augusta Township, but in 1785, Catawissa Township split off from Augusta, with Gravel Run part of the border between the two. Three years later, in 1788, Ralpho Township split from Catawissa, and included the land that bordered Augusta; Ralpho was renamed Shamokin a year later. In 1819, Rush Township was created by splitting