A CROPMARK ENCLOSURE AND A SHERD OF LATER NEOLITHIC POTTERY FROM BRYNDERWEN, LLANDYSSIL, POWYS ALEX GIBSON' and CHRIS MUSSON2 INTRODUCTION The findings described in this note were made during periodic monitoring carried out in 1978 during construction of the Welshpool to Newtown gas main by Wales Gas. Approximately 300 m NNE of Brynderwen farm, near Llandyssil, the pipe-trench passed through a small sub-rectangular enclosure (SO 166956), about 100 m across, discovered during aerial reconnaissance by Cambridge University in July 1953 (fig. 1).' Three sides of the enclosure are clearly visible on aerial photographs taken at that time; the fourth, eastern, side doubtless lies beneath the modern railway or adjacent copse. The north and south ditches of the enclosure were identified in the sides of the pipe- trench, although there was insufficient time to make a detailed recording of the section. Topsoil and subsoil at this point were between 30-50 cm thick, overlying natural gravel. The southern ditch was 75 cm from the top of the gravel; it measured 2.7 m wide at the gravel surface and both sides sloped down gently to a rounded base. The upper fill contained less gravel than the surrounding subsoil, and included flecks of charcoal and possible pieces of calcined bone. The northern ditch was rather more V-shaped in profile, being about 1 m deep from the surface of the gravel, and about 1.4 m wide. Once again, charcoal flecks were noted in the gravel fill. In this instance there was possible evidence for either an earlier feature cut by the ditch or for an earlier cutting of the ditch in the section visible in one face of the pipe-trench. Inside the enclosure ditches, and about 15 m to the north of the southern ditch, was a further ditch, about 1.7 m wide and 1.1 m deep from the surface of the gravel, running obliquely to the pipe-trench, with a similar fill to the enclosure ditches. Two pits were also recorded inside the enclosure. The first, noted in the east face of the pipe-trench, had a bowl-shaped section and was 1.7 m wide and 55 cm deep below the gravel surface. It contained yellow-brown soil with a thin lens of charcoal midway down the fill. The second pit, further to the north, noted in the west section of the pipe-trench, was 65 cm deep and 50 cm wide. Cleaning the section of the second pit revealed fragments of charcoal, several carbonised hazelnut shells and the fragment of later neolithic pottery illustrated in Figure 2. THE POTTERY The sherd (fig. 2a) represents part of the rim and upper body of a collared vessel. The fabric is quite hard and well-fired, containing abundant large inclusions of ?dolerite, up to 4 mm across. Many inclusions break through the inner surface of the vessel. The outer surface is grey-brown, the inner surface varies from black to pink; the core of the sherd is black. Traces of join voids are clearly visible in the fabric and much of the inner surface is covered with carbon encrustations. The Clwyd-Powys Archaeological Trust, 7a Church Street, Welshpool, Powys SY21 7DL. 2 Former Director of CPAT, now of the RCAHM (Wales), Edleston House, Queens Road, Aberystwyth, Dyfed. Powys Archaeological Record No. PAR 188. Cambridge University air photograph No. MM67.