A similar problem exists with the interpretation of Neolithic axes; while there cannot be any doubt that glacial drift has resulted in the deposition of rocks at a considerable distance from the parent rock, it is difficult to determine the actual source of the stone in either period. BNC
Gold appears either in its parent rock or in placer deposits in which the products of long periods of erosion are concentrated in the alluvium of existing river systems or buried under later sedimentary or igneous rocks. BNC
Neither is to be found in alluvial sands or gravels and both have to be mined from the parent rock. BNC