The portal dolmen of Dyffryn Ardudwy, Merioneth. The original dolmen is left of centre. Later the tomb was enlarged by the addition of the eastern chamber and rectangular mound. The smaller drawings show cross-sections of the west and east chambers. (After Lynch, 1969)
In the west and north of Britain the place of the earthen long barrows with wooden chambers was taken by megalithic structures utilizing the local building stone—megalithic means ‘great stones’. The earliest tombs were probably portal dolmens. These are usually small, free-standing stone chambers with few or no circular mounds or stone cairns around them. The chambers are rectangular, becoming lower and narrower towards the rear. A sloping roofstone rests on two portal stones which mark the entrance and project beyond the chamber to form a porch. Between these two stones is a third septal or blocking slab, which often reaches up to the roofstone and acts, in theory at least, as a door. In parts of west Wales tombs can be found in which these features are no longer very obvious, suggesting that the type has a long uninterrupted history of devolution.
Today most portal dolmens are in a ruinous state. Sweyne’s Howe North in Glamorgan has all the typical components but the capstone has slipped backwards and the blocking slab has fallen forwards. Modern excavations have taken place at Trefignath and Din Dryfol in Anglesey and at Dyffryn Ardudwy in Merioneth. At the latter site a complete portal dolmen with a Vshaped forecourt was examined (fig. 20). In the disturbed chamber only one cremation burial remained, whilst in a pit beneath the forecourt were many fragments of plain-bowl style neolithic pottery. The whole tomb was originally enclosed in an oval cairn of stones. Sometime later a new and larger rectangular burial chamber, measuring 2 m. (2.2 yd) by 1.5 m. (1.6 yd) and not dissimilar to a portal dolmen, was constructed 10 m. (11 yd) east of the first. (Its contents had been robbed before the excavation.) Eventually, when access to neither burial chamber was required, a rectangular cairn of stones 30 m. (33 yd) long was constructed to enclose both tombs.
The Whispering Knights near the Rollright Stones in Oxfordshire is a ruined portal dolmen, as is Kit’s Coty House, an outlier in Kent. Related but not exactly similar tombs can be found in Cornwall where they are sometimes called Penwith chamber tombs, and of which Trethevy Quoit is the best example.
It has been suggested that whether built of wood or stone the burial chambers imitate the houses of the living, and that in them not only would the remains of the dead lie in perpetuity but also their spirits could dwell and watch over the living. Indeed the position of many of the tombs on hilltops might be a clue as to the location of neolithic settlement. It is dangerous to suggest modern parallels but perhaps the majority of tombs served a function more akin to medieval parish churches, in that they provided a structure in which to perform religious ceremonial and at the same time were the burial places of a small, selective group of the parish dead, added to only occasionally over hundreds of years.
Broadly speaking the chambered tombs of Britain can be divided into two groups, first recognized by Glyn Daniel, and known as gallery and passage graves. The gallery graves consist of long stone passages either divided into sections with cross (septal) slabs, or with chambers on either side. They normally occur in rectangular mounds. Passage graves have longish passages, opening into a round or rectangular chamber at the end; there is usually a circular covering mound. These occur mostly in western and northern Britain.