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
Wivenhoe Gravel Pit Wivenhoe Gravel Pit Wivenhoe Gravel Pit is a 2.1 hectare geological Site of Special Scientific Interest north of Wivenhoe in Essex. It is a Geological Conservation Review site. The site is the type locality for the Wivenhoe Gravel, which was laid down by the River Thames before it was diverted south to its present course by the Anglian glaciation around 450,000 years ago. The gravel was laid down during two cold stages with an intervening interglacial, but the fossils in from this warmer period are not distinctive enough to identify which interglacial they come from. The site is important for