Chemical Alteration (Patination) of Stone

and their causes. It must be admitted initially that the use of patination as an aid in assessing the relative order of cultural assemblages is limited and circumscribed. It is perhaps of less value in the field than the fluorine test. This latter is limited absolutely to sites at which both fluorine and bone are present. It proved its worth sensationally with the Piltdown fragments; but highly important supporting evidence was supplied by the chemical recognition of the clearly improbable 'patina' on those fragments. Both chemical actions are inimitable and irreversible. In spite of limitations, if a pattern of evidence can be harnessed to help us, it must be employed even if only guardedly, however slight its value may be. Let us first consider my task in South Africa in 1923 (Goodwin, 1958). The great bulk of known stone implements at that time had been derived from surface sites, material distributed by the slow denudation of a great expanse of Karroo plateau with low summer rainfall in the southern interior, or from the foothills of the Cape System with its winter rainfall.