Silt semi-arid environments that substantial quantities of silt are produced. Silt is sometimes known as "rock flour" or "stone dust", especially when produced by glacial action. Mineralogically, silt is composed mainly of quartz and feldspar. Sedimentary rock composed mainly of silt is known as siltstone. Liquefaction created by a strong earthquake is silt suspended in water that is hydrodynamically forced up from below ground level. In the Udden–Wentworth scale (due to Krumbein), silt particles range between 0.0039 and 0.0625 mm, larger than clay but smaller than sand particles. ISO 14688 grades silts between 0.002 mm and 0.063 mm (sub-divided up into
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