this scenario, the monuments would be composite structures. The Medway Megaliths' builders were probably influenced by pre-existing tomb-shrines elsewhere that they were aware of. Whether the builders had grown up locally, or moved into the Medway area from elsewhere is not known. Based on a stylistic analysis of their architectural designs, the archaeologist Stuart Piggott thought that the plan behind the Medway Megaliths had originated in the area around the Low Countries, while fellow archaeologist Glyn Daniel instead believed that the same evidence showed an influence from Scandinavia. John H. Evans instead suggested an origin in Germany, and Ronald F. Jessup thought that their origins could be seen in the Cotswold-Severn megalithic group. Alexander thought that they bore closest similarities with long barrows along the Atlantic coast, perhaps imitating those of either Ireland or Brittany. The archaeologist Paul Ashbee noted that their close clustering in the same area was reminiscent of the megalithic tomb-shrine traditions of continental Northern Europe, and emphasised that the Medway Megaliths were a regional manifestation of a tradition widespread across Early Neolithic Europe. He nevertheless stressed that a precise place of origin was "impossible to indicate" with the available evidence. Design and construction Archaeological excavation revealed a Mesolithic layer below the monument, evidenced by much debris produced by flint knapping. During the 1957 excavation of the site, 2,300 Mesolithic flint fragments were found beneath it. Many more have been discovered in test trenches around the area, stretching up the hill towards Chestnuts Wood and for at least east of the tomb and south-west of it. Around west of the long barrow, excavation revealed flints in association with what was interpreted as a Mesolithic hearth. The large quantities of Mesolithic material, coupled with its broad spread, indicated that the site was probably inhabited over a considerable length of time during the Mesolithic period. Some trenches excavated in 1957 had Mesolithic flints directly below the megaliths, leading the excavator John Alexander to believe that "no great interval of time separated" the Mesolithic and Neolithic uses of the site. Chestnuts Long Barrow was constructed in particularly close proximity to Addington Long Barrow. The chamber was built with sarsen stones that occur naturally within a few miles of the site. These were arranged as two trilithons, next to each other, so that the two lintel stones formed the roof of the chamber. The chamber was trapezoidal in shape, measuring about