There is little doubt that the small lithic assemblage from the Isles of Scilly is totally different to that from any other Mesolithic site in Britain. As the authors correctly state, the general resemblances to trapeze-dominated assemblages from the continent, in particular to the Late and Final Mesolithic industries from northern France, Belgium and the southern Netherlands, are very obvious. Typologically, the majority of armatures relate to continental rhombic trapezes, called ‘trapèzes à bases décalées’. Upon closer examination, however, several armatures display morphological or technical features that deviate from continental trapezes, making the Scilly assemblage both unique and enigmatic within north-west Europe. In particular, the presence of a dorsally or ventrally retouched base between both truncations on at least 20 of the armatures (p. 962, fig. 5) is remarkable. This is a feature that does not occur on continental trapezes, not even on the evolved rhombic trapezes known as flèches de Dreuil. The latter are particularly numerous in assemblages from the Somme valley (Ducrocq Reference Ducrocq1991), near the coast where the Channel crossing is narrowest. The combination of a length–width ratio typically <1 and the general use of flakes as blanks prompts us to interpret these implements as transverse arrowheads rather than standard trapezes. Pursuing this interpretation, the basal retouch might have been applied in order to facilitate their hafting, while the irregular small ‘splinters’ on the unretouched opposite end, visible on several of the drawings, might correspond to damage resulting from use.

Although the transition from trapezes (made on regular ‘Montbani’ blades and bladelets) to transversal arrowheads on the continent is still poorly understood recent research in the Scheldt valley in Belgium has highlighted major changes during the course of the fifth millennium cal BC (Robinson et al. Reference Robinson, Lombaert, Sergant and Crombé2011; Lombaert et al. in press). Armatures found at the Swifterbant Culture sites of Doel ‘Deurganckdok’, dated to the second half of the fifth millennium cal BC, are less standardised and smaller than trapezes of the sixth millennium cal BC. In addition, echoing the Scilly examples, they were no longer made on regular blades as small flakes were used instead. Except for the basal retouch and general morphology, the armatures of Scilly seem to match these fifth millennium transverse arrowheads better than real trapezes. If this is confirmed by future radiocarbon dates, it will constitute one of the strongest pieces of evidence of cross-Channel contact after the inundation of the North Sea basin around c. 7000 cal BC. It certainly fits with the few other indications of cross-Channel connections, such as the cow bones from Ferriter's Cove in south-west Ireland and the jadeitite axes of Alpine origin found across Britain; both also dated to the second half of the fifth millennium cal BC. With the exception of a recent claim that sedimentary ancient wheat DNA was discovered at the c. 8000 year old submerged Mesolithic site of Bouldnor Cliff (Smith et al. Reference Smith, Momber, Bates, Garwood, Fitch, Pallen, Gaffney and Allaby2015), there is little proof of interaction between the British mainland and the continent before the mid-fifth millennium. The evidence, although still limited and difficult to interpret, seems to indicate that increased contact with the Continent occurred at the same time as the acculturation of Mesolithic hunter-gatherers in the Rhine-Meuse-Scheldt estuary of the Belgian and Dutch lowlands accelerated (Raemaekers Reference Raemaekers2003; Louwe Kooijmans Reference Louwe Kooijmans, Whittle and Cummings2007; Crombé et al. Reference Crombé, Verhegge, Deforce, Meylemans and Robinson2015). The adoption of pottery manufacturing (c. 5000 cal BC in the Rhine and Meuse delta and c. 4600 cal BC, in the Scheldt valley) and the introduction of the first domesticated animals and cereals in the course of the second half of the fifth millennium led to a gradual Neolithic transition in the local (Swifterbant Culture) population. Ultimately by 4300 cal BC both domesticated animals and cereals had become available along the southern North Sea coast, whereas before that time these had still been confined to the loess area of Western Europe, situated at least 100km from the Channel coast. The proximity of these new commodities might have triggered or stimulated cross-Channel maritime contact and exchange. So perhaps the excavators of the new site on Scilly should expect to find other evidence of these contacts amongst the recorded finds, for example, among the Early Neolithic pottery.