Gravel areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or tarmac; Russia alone has over of gravel roads. Both sand and small gravel are also important for the manufacture of concrete. Large gravel deposits are a common geological feature, being formed as a result of the weathering and erosion of rocks. The action of rivers and waves tends to pile up gravel in large accumulations. This can sometimes result in gravel becoming compacted and lithified into the sedimentary rock called conglomerate. Where natural gravel deposits are insufficient for human purposes, gravel is
Fern House Gravel Pit no public access. Fern House Gravel Pit Fern House Gravel Pit is a 1.3 hectare geological Site of Special Scientific Interest in Fern, near Bourne End in Buckinghamshire. It is also a Geological Conservation Review site. This site exposes the Pleistocene Taplow Gravel formation, and may help to elucidate a poorly understood period in the history of the River Thames, between glacial Anglian stage, around 450,000 years ago, when the river was diverted south to its present course, and the warm Ipswichian around 120,000 years ago. Fossils found at the site include straight-tusked elephants and mammoths. The site is on