The eastern end of the Vale of Pickering, in which the archaeological site lies, has been considerably affected by glaciation, and did in fact provide many of the earliest examples of ice work to be described in this country (Fox Strangways 1880, Kendall 1902). The only glacial feature which need concern us at present, however, is the large number of mounds of drift, principally gravel and sand. These occupy the floor of the valley and frequently protrude through the superimposed muds and peats of late- and post-glacial age. It was on the slope of one of these mounds that the mesolithic people lived, as the section (fig. 7) clearly shows.