The latter wares are discussed further by Giot and Querre (1986). The principal outcrops of the clays containing these spicules are concentrated in southern Brittany, with smaller outcrops on the Normandy peninsular ( ibid., fig.2) and they are exploited intermittently from the Bronze Age until the present century. During the early Roman period the ware is known on a number of sites in the valley of the Vilaine, Alet on the north coast and also further west. At Corseul it is suggested that the moulded-rim jars in the spicule-tempered wares are preceded by examples in micaceous fabrics and judging by the published descriptions some of the latter may be TF1.