The word EXCAVATION has two meanings. It is used primarily in the field of archaeology and is the most used technique in this field. In archaeology, it is the exposure, processing, and recording of archaeological remains. In another sense it is a term to refer to a dig. The digs or excavations of a particular archaeological site may take place over the course of many years. So, basically it means to dig or to hollow out. It can also mean to dig or remove soil, to uncover or unearth by digging. Excavation initially involves the removal of any topsoil overburden by machine. This material may be examined by metal detector for stray finds but unless the site has remained untouched since its abandonment there is invariably a layer of modern material on the surface of limited archaeological interest.