A round barrow is a type of tumulus and is one of the most common types of archaeological monuments. Although concentrated in Europe, they are found in many parts of the world, probably because of their simple construction and universal purpose.
In Britain, most of them were built between 2200BC and 1100BC. This was the Late Neolithic period to the Late Bronze Age. Later Iron Age barrows were mostly different, and sometimes square.
A tumulus (pl.: tumuli) is a mound of earth and stones raised over a grave or graves. Tumuli are also known as barrows, burial mounds, mounds, howes, or in Siberia and Central Asia as kurgans, and may be found throughout much of the world. A cairn, which is a mound of stones built for various purposes, may also originally have been a tumulus.
Tumuli are often categorised according to their external apparent shape. In this respect, a long barrow is a long tumulus, usually constructed on top of several burials, such as passage graves. A round barrow is a round tumulus, also commonly constructed on top of burials. The internal structure and architecture of both long and round barrows have a broad range; the categorization only refers to the external apparent shape.
Nash Point (Welsh: Trwyn yr As) is a headland and beach in the Monknash Coast of the Vale of Glamorgan in south Wales, about a mile from Marcross. It is a popular location for ramblers and hiking along the cliffs to Llantwit Major beach. The lighthouse meadow is a Site of Special Scientific Interest, containing rare plants such as the tuberous thistle, and other wildlife such as choughs can be seen.
Parts of the section of the Glamorgan Heritage Coast where the lighthouse stands consists of "cliffs of Lias limestone interbedded with softer erodible material" and has been identified as potentially at risk from erosion and flooding. Many fossils, including ammonites and gryphaea are to be found there. Marcross Brook passes through the cliffs and an Iron Age hillfort, usually called Nash Point Camp, stands on the north side of the brook, although its remains have been largely eroded by the sea. Round barrows are also to be found nearby. A study of the rocks shows that they exemplify "a 12,000 year old sequence oftufa, scree and slope deposits containing abundant fossil snails", while the Nash Bank offshore is formed by "Jurassic mudstones overlain by bands of sand andgravel".