2.2 Fieldwork on erratics

By this point, to gain a better idea of the available resources for myself, I began more literature searches and also visited the locations where erratics had already been described. Stimulated by Clarence Ellis's popular book (1964), I searched numerous beaches around the British Isles, including classic East Yorkshire sites like Dimlington in Holderness. The great variety of lithic materials that could be seen on the Yorkshire coast further strengthened my conviction that these deposits demanded detailed petrographic examination in order that their potential relationship to the stone axes, if there was one, could be better understood.

It is a wonderful experience to stand on a shingle bank and watch its metamorphic, igneous and sedimentary pebble components change colour as if by magic when rain begins to fall. Besides being a great lesson in geology – where did all the pebbles come from? – it raises questions about the stones' qualities as a tool-making resource. Although evidence for such a variety of lithic material is so obvious for all to see, prehistorians seemed to feel uncomfortable with the suggestion that beach or ice-borne pebbles could ever have been useful to prehistoric peoples (even though that premise had been widespread during the later nineteenth century). Indeed, after showing an image of pebbles on Dimlington beach at the York conference, one delegate argued that they were all the wrong size for making stone axes! So even if it could be demonstrated that the right materials had been available, prehistoric man would have been disqualified from using them.

The other area that had to be researched, was the published literature documenting glacial dispersals. It was also necessary to consult official records listing the petrographic examination of erratics at the The Geological Survey (now the Institute of Geological Sciences) headquarters then in London. The Survey's petrography had usually been undertaken sporadically, to a standard that enabled only the most basic recognition. The resulting thin sections were often interpreted with only limited understanding of their country rocks' location or origins. Consequently, these searches proved to be of very limited value in assessing the whereabouts or identity of the total lithic resource of Britain's superficial deposits. A more useful initiative was taken by Williams-Thorpe et al. in 1999, when they provided a topographical gazetteer of potential rock sources and types that may have been used by prehistoric man (Williams-Thorpe et al. 1999, 238-42).


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