The tomb in Rhoslan, also called Cefn Isaf, was built during the Neolithic period, around 4400 – 2900 BC. Constructions of this type were used by early-agricultural communities, as collective burial sites and for perhaps religious ceremonies. The decline in the use of megalithic tombs occurred around 2500 B.C. During the coming Bronze Age, until about 1500 B.C. in Britain, other burial methods, including those related to stone circles, gain more importance.
The burial chamber consists of four vertically arranged stones, supporting the largest capstone serving as a ceiling. It is open to the south-east, 2.4 meters along its axis from north-east to south-west and 1.8-meter wide at its north-eastern end. The inner height is 1 meter. The capstone is flat underneath with a maximum thickness of 1 meter, the plan is roughly rectangular with a length of 3.5 and a width of 2.75 meters, with a detached southern corner. The whole was originally covered with a mound of earth or stones, which now completely have dispersed.
Website ancientmonuments.uk, Cefn-Isaf Burial Chamber.
Website megalithic.co.uk, Rhoslan – Chambered Tomb in Wales in Gwynedd.