What is a Dolmen? - A Glossary of Prehistoric Monuments in Britain

How to Understand Prehistoric Buildings in the Uk

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Britain is littered with mysterious man-made structures that are thousands of years old, each with its own special name. 

Guidebooks lead us to dolmens, brochs, cromlechi, menhirs as though everyone knows what they are. But what are these things anyway? What do we know about them? And most important, how can you tell what you are looking at when you see one?

This alphabetical glossary of the terms used for prehistoric monuments in Britain should help you understand some of these mysteries.


Raised earth and stones over a grave or group of graves. Also called a mound or tumulus.


Iron Age building, found in north and west Scotland. It is a massive, round tower built with double-skinned, dry stone walls. The two walls one inside the other had a space between them and were tied together at various points. This feature meant the towers could rise to up to more than 40 feet. They were once thought to be for defense, but there are so many of them that archaeologists now think they had a different purpose. They suggest they were simply statements of ownership or presence on the land meant to impress outsiders. At least 50 have been discovered in Orkney although only a few of them are excavated.


British term for a cowshed. Prehistoric byres would have sheltered other livestock, and sometimes grain, as well.


At its most basic, a cairn is an arrangement of large stones placed as a memorial, a marker or a warning. In Britain, a ring cairn is a Bronze Age ritual site - a large circle of stones, found mostly in the Northwest of England, perhaps 50 or 60 feet in diameter. Excavations have found evidence of fires and human burials inside these. Kerb cairns, common in mid-Wales, are small circular mounds, surrounded by a kerb of stones that are higher than the mound.


Prehistoric causeways were Iron Age paths across boggy land. They were laid with timbers on pilings to provide a firm footing. The Fiskerton Causeway in the Witham Valley of Lincolnshire was created around 600 B.C.

Chambered Tomb

Burial places accessed through some kind of portal and divided into one or more rooms for individuals, like a modern mausoleum, suggesting high status burials. Unexcavated chambered tombs look like mounds on the landscape. Some archaeologists now think that the bigger chambered tombs served a ritual function much as modern cathedrals do. 


An early form of "coffin" burial in a chest or stone box.

Clapper Bridge

Bridges built of long stone slabs supported by dry stone constructed piers. Because of their heavy constructions, they may have been built to allow pack horses to cross small streams. Clapper bridges exist in Dartmoor and Exmoor as well as Snowdonia in Wales. Some date from the middle ages and many are still in regular use on walkers paths.


A small artificial island, site of a prehistoric shelter or house and found in lakes and estuaries in Scotland and Ireland. In the west of Scotland, crannogs have a foundation of stone and are usually overgrown with vegetation because animals don't graze on them. In some places, crannogs were built on wooden pilings.


A word used in Wales to described a chambered tomb or the entrance of a chambered tomb. It's similar to a dolmen (see below).


A large flat stone supported by vertical stones in the form of a portal. Dolmens are the remains of Stone Age tombs after the mounds (or tumuli) associated with them have eroded away. It's also possible that dolmens were only symbolic portals.


A circular or oval earthwork with a built up bank and a ditch inside the bank used for ceremonies or for calculating time and seasons. The name henge comes from Stonehenge, the most famous example. Its name comes from the Anglo Saxon for hanging or hinged stone. Much is made of the alignment of the sun, or moon, with various configurations of a henge. At the Summer Solstice, crowds of people arrive at Stonehenge to celebrate the shortest night of the year. But, in reality, the purpose of these alignments is still, pretty much anybody's guess.

Hill Fort

Massive earthworks, from the Iron Age or earlier, with steep slopes and elaborate systems of ramps. Though they are defensive, often built on the highest ground in an area, Iron Age hill forts also supported small settlements of homes and workers. Maiden Castle in Dorset and Old Sarum, near Stonehenge, are both examples of hill forts.


A large standing stone, sometimes carved with Stone Age art and symbols. Menhirs can be single standings stones, like the immense Rudston Monolith in the Yorkshire Wolds. About 26 feet tall, this menhir, in the All Saint' churchyard in Rudston, is the tallest standing stone in Britain and was erected about 1600 B.C. Other mehirs may be in groups or even stone circles. The Standing Stones of Stenness is a group of menhirs.

Passage Tomb

Similar to chambered tombs, passage tombs have an internal passage, lined with stones and roofed with stone lintels, leading to an internal, ceremonial chamber. Maeshowe on Orkney is a remarkable passage tomb buried under a large circular mound. Orkney has many similar, currently unexcavated mounds.


A roundhouse dwelling found in the Western Isles of Scotland. A prehistoric wheelhouse has outer stone walls and stone piers, arranged like the spokes of a wheel, that support stone lintels and a stone roof.

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