31. Above these alluvial deposits , the sediments become coarser and are frequently interspersed with diatomaceous material. 32. The valley of the Witham includes its own alluvial deposits of clay, silt and Gravel. 33. Alluvial deposits form the soil, which is acidic.34. Alluvial deposit is normally found along the banks of the Manjra river and its main tributaries.35. First alluvial deposits of clays, silts and sand occur from streams tributary to a given bay. 36. Most of the area around River Avon at Keynsham there are alluvial deposits of clay soils. 37. Alluvial deposits known as the Sezze Fan began about 4000 BC in the marsh below Sezze.38. Alluvial deposits deep cover the site and have protected it from recent activity on the surface.39. The plateau is characterized as being of clay with components of gravel, gneiss pebbles, alluvial deposits . 40. Initially this was working alluvial deposits of gold but later focused on the mining of quartz reefs.
