The type here discussed is a common feature of most collections of surface flints from this country, but little serious study has been devoted to it ; and though it has frequently been found in datable associations, no one seems to have attached it to any particular culture. Collectors in East Anglia have long called specimens of the type ‘slugs ’, a term unfortunately employed in other areas, for instance Sussex, to describe flint fabricators. In view of this confusion the author suggests the use of the term ‘plano-convex-knife ’ which accurately describes the section of the implement. The type is characterized by pressure or scale flaking on the slightly convex upper face, the under surface retaining the flake surface, usually with the bulb and sometimes with the striking platform intact. As a general rule the flake from which the knife is made shows a distinct curve in its longitudinal axis. As a result of the fine pressure technique employed, the convex surface of the implement commonly gives a glossy or soapy feel to the touch. In the finer and more typical specimens the whole of this upper surface shows the characteristic secondary flaking, though in some cases the central area of the flake is allowed to retain its primary character. In plan the commonest form is elongated oval of varying width (nos. 1 and 2), which is in a few examples (e.g. one from Bishop's Burton, barr. CCLV) serrated round the entire edge save for the buttend. The point is normally obtuse, if not rounded, and in a few cases (no. 3) is trimmed to a scraping edge. Finally we have to note rather a distinct variety with a straight chisel-like extremity (no. 4) from which flakes have been removed in the main line of the implement. This particular specimen has lateral notches as though for hafting.