 Archaeological excavations carried out between 1953 and 1955 by Philip Rahtz and Ernest Greenfield from the Ministry of Works found evidence of extensive human occupation of the area . Consecutive habitation , spanning thousands of years from the Upper Palaeolithic , Mesolithic , and Neolithic periods ( Old , Middle , and New Stone Age ) , to the Bronze and Iron Ages had left numerous artefacts behind . Discoveries have included stone knives , flint blades , and the head of a mace , along with buildings and graves . 
