`Clay-with-flints' refers to deposits lying on the hilltops and plateaux of the Chalk Downlands of southern England. This study is based on the archaeology, geology and sedimentology of these deposits and forms a comprehensive review of the Palaeolithic stone tools found embedded within them. Evidence relating to the author's excavations at the Lower Palaeolithic site of Wood Hill in East Kent (1993-1994) provides the foundation for her discussion of these clay-with-flint deposits and the earliest occupation of southern England. Since this work presents much new information, two explanatory sections outline the theoretical analysis of the deposits and the processes of their function as well as the methodology for studying and identifying in-situ Palaeolithic material.