Petersburg, West Virginia. Petersburg is a city in Grant County, West Virginia, USA. The population was 2,467 at the 2010 census. It is the county seat of Grant County. Contents.
The particles that make up soil are categorized into three groups by size: sand, silt, and clay. Sand particles are the largest and clay particles the smallest. Although a soil could be all sand, all clay, or all silt, that's rare. Instead most soils are a combination of the three.
The rock that breaks down into mineral fragments that form a soil is called parent rock. Different parent rocks have different chemical compositions. As a result, soils also differ in composition. Bedrock is the layer of rock beneath soil.In some cases, the bedrock is the parent rock. In these cases, the soil remains above the bedrock that weathered to form the soil.Soil that remains above its parent rock is called residual soil.Few soils are residual soils.any people think that soil is just dirt. To a scientist, soil is a loose mixture of small mineral fragments, organic material, water, and air that can support the growth of vegetation. The Source of Soil Because soils are made from weathered rock fragments, not all soils are the same.