It is appropriate to introduce this chapter with some remarks on the most recognizable features of the post-glacial deposits on the North Ferriby foreshore as sources for a wide range of artefacts. The boulder clay and overlying greenish, sandy, weathering layer charged with frost-fractured flint need not concern us, both being barren deposits of the Ice Age. The variation in thickness of the succeeding peat bed between the hollows and ridges in the boulder clay can be confusing since over the ridges, including that immediately to the west of the boat site, it is almost entirely absent. The peat reaches its maximum development to a thickness of 1.07 m in the hollow to the west of this ridge (Figure 8.1); but in the area of the boat site it is rarely more than 0.30 m thick; in certain places the upper layer shows signs of erosion before deposition of the overlying grey estuarine clay, whereas elsewhere the transition from one to the other is gradual. The peat layer is not only typically dark brown in colour but also has a solid texture which can be crumbled or broken but is never plastic. It is therefore virtually impossible after its formation for an artefact to become embedded in it from the outside, and by extension it can be assumed with certainty that an object found protruding from it arrived where it did during the accumulation of decaying vegetable matter from which the peat developed. These conditions do not necessarily apply in the case of the estuarine clay and any other similar
sediments which succeeded it. It is a practical possibility that artefacts of hard and heavy materials can sink in such deposits, unlikely that they can rise, but possible that they can be moved sideways and be redeposited. The likelihood of such movement from the original place of deposition may be less in the case of waterlogged wooden objects but is not entirely removed. It is necessary therefore to emphasize the principle that proximity of artefacts to each other either vertically or horizontally is no absolute guarantee of association. Nevertheless in the conditions prevailing in the 1930S and 1940S and occasionally later the bank was so clean of recently deposited silt that with regular observation it has been possible to say with confidence whether or not an artefact or other object could be associated with the clay surrounding it and only been revealed by new erosion. Such conclusions were in certain cases reinforced if the consistency of wooden objects was unusually soft. What cannot be guaranteed is that the clays represent a single phase of deposition. Ideally it would have been desirable to obtain radiocarbon dates for all major artefacts, but two of the larger ones were lost in World War II. Direct dating has so far covered only the boats and adjoining structures. In fact all the radiocarbon-dated wooden artefacts from the estuarine clay together with the single metal object and all but two of the potsherds (ascribed to the Early Iron Age) can be assigned to the Bronze Age. My presumption
one end exposed and the remainder securely buried in estuarine clay.