Stone circles represent the zenith of the megalithic era. Archaeologists date them to 2500-2200 BCE though the author suspects they might be a little earlier, around 2600, and all possibly built within a few decades of each other.
West Penwith has four surviving circles, though once there were around ten. Tregeseal and the Merry Maidens were once made up of two or three circles each, and the Mên an Tol once was a stone circle.
On this page: The Appliance of Science - Surviving Stone Circles - Disappeared Stone Circles - Stone Circle Design - Stone Circle Astronomy
Penwith's four surviving stone circles are Tregeseal and the Nine Maidens in the north, and Boscawen-ûn and the Merry Maidens in the south. These two pairs contrast one another in character and setting.
Tregeseal and the Nine Maidens in the north are each overshadowed by a neolithic tor hill - Carn Kenidjack and Carn Galva. Boscawen-ûn and the Merry Maidens in the south are situated on flatter rolling lands, once upon a time mainly wooded. This said, a significant hill is distantly visible from both of the southern circles - Chapel Carn Brea from Boscawen-ûn and Carn Galva from the Merry Maidens.
All of them have a complex of orbital sites attached to them within a mile or so, made up of menhirs, barrows, stones and, in two cases, now-destroyed stone circles. The stone circles stand at the hubs of geomantic complexes or landscape temples, each with a number of features and wrapped in an enveloping landscape setting. These complexes should not be seen as separate from the stone circles. More about them on the next page.
Stone circles' landscape settings are more visible nowadays in the two northern circles because they are located on open moorland while the southern circles are situated in farmland, with hedgerows and obstructions affecting the look and feel of the landscape.
The appliance of megalithic science
The positioning of stone circles offers clues about their purpose and role. The stone circles are located where they are because of complex and carefully thought out megalithic scientific considerations. Nowadays we understand only snippets of bronze age science.
The megalith builders utilised advanced mathematics, astronomy, geometry and proportion. They understood the dimensions of the Earth, the periodicity of the planets, the eclipse cycle, the precession of the equinoxes, the Golden Mean and Pythagorean geometry (2,000 years before Pythagoras) and they embodied these principles in the design, size and shape of the stone circles. They planned out their megalithic works to reflect their perception of the cosmos - this much is visible in what they have left behind, though fully understanding these works is far more challenging.
Positioning contains further clues. The location of the stone circles in West Penwith is determined by backbone alignments. The circles are aligned with neolithic tor enclosures and cliff sanctuaries, the most important sites of the neolithic a millennium earlier in the 3000s BCE. So the newer sites (the stone circles) are positioned in calculated relation to the old sites.
Thus, for example, the Tregeseal stone circle is located in exact alignment with Carn Brea, Trencrom Hill and Lanyon Quoit - two neolithic tor enclosures and one neolithic quoit. The Merry Maidens are on an exact alignment between Carn Brea, St Michael's Mount and Treryn Dinas. Boscawen-ûn, meanwhile, is located at the node of six backbone alignments, every one of them connected with a cliff castle.
The people of the bronze age plugged their technological inventions into what they saw as a natural network and an ancient heritage, staked out by tor hills and cliff castles, first identified and staked out by the people of the neolithic in the mid-3000s, fifty generations before.
The stone circles became the key nodes in a wider system of bronze age sites spread out across the landscape.
Map showing the role of backbone alignments in the location of stone circles in West Penwith
The surviving stone circles
Tregeseal stone circle is situated on alignment 83 going from Carn Brea near Camborne to the Brisons rocks just off Cape Cornwall, passing exactly through Trencrom Hill and Lanyon Quoit (see map above). The anchor or contact-point for this alignment is not the stone circle itself but Botallack Common barrow, 200 yards ENE of the circle and part of the Tregeseal complex.
Tregeseal is what's called a Type A flattened circle with a diameter around 21m. Circles were flattened on one side in order to adjust the relationship between their diameter and circumference, to make it into a significant mathematical proportion reflecting astronomical factors such as the ratio of the length of day and night at the two solstices, at this particular latitude.
Tregeseal stone circle is the eastern of two or three original circles, the others having been destroyed by landowners. The central circle existed until 50ish years ago, and some of its stones survive today, laid horizontally in the hedge (wall) next to the surviving circle. The western circle is not clear and might not have been a stone circle, but a circular shape does show up in aerial photos of crop marks.
Tregeseal is overshadowed by Carn Kenidjack and set in a slight bowl beneath it, with several chambered cairns and holed stones comprising its complex, as well as a small rock carn lying immediately southeast of the circle, plus two more distant menhirs - Boswens east-northeast and Carn Eanes northwards. In its heyday, these circles would have formed an impressive presence.
The Merry Maidens circle stands on alignment 112, an exact alignment of Carn Brea (a tor enclosure), Gear Round, St Michael's Mount (a tor enclosure and cliff sanctuary) and Treryn Dinas (a cliff sanctuary). This remarkable alignment involves three aligned natural features. The Merry Maidens circle was placed exactly on this alignment.
The circle is in quite good shape. Close to the road, it attracts more visitors than the other circles - if you're a meditator, you have to take your chances. This stone circle is exactly circular (only some stone circles are), and 24m in diameter.
The field patterns and hedgerows surrounding it have obscured and decontextualised the other sites that make up the Merry Maidens complex, and the one or two nearby stone circles have also been destroyed by farmers - the last vestiges of one, Tregurnow, were removed only in the 1990s. It is possible that Tregurnow was a bigger circle - there is no sign of it now. The other possible circle, Boleigh, is disputed, indistinctly reported by 19th Century antiquarians, with little corroborating evidence.
The Nine Maidens or Boskednan stone circle stands at the intersection and terminus of two major alignments, 96 and 38. Alignment 38 goes from Treryn Dinas through Boscawen-ûn, to Lanyon Quoit, then to the Nine Maidens (specifically to a menhir, nowadays a broken stub, some 20 yards NW of the circle). Alignment 96 goes all the way from Rame Head near Plymouth, through Roundwood Fort near Truro, to Trencrom Hill and then to the centre of the Nine Maidens circle.
This is the most damaged of the circles (this time by miners), yet its location on a high moorland saddle under Carn Galva, overlooking a broad landscape, is the most inspiring of all of the Penwith stone circles. Like the Merry Maidens, the Nine Maidens is exactly circular, with a diameter around 22m. From the Merry Maidens Carn Galva has a pyramidal shape (while from the east or west it is more like a dragon's back) and its presence dominates the Nine Maidens.
The original Mên an Tol stone circle down the hill formed part of the Nine Maidens' landscape temple, together with Bosiliack Barrow and several cairns and stones, as well as the nearby hills Carn Galva and Watch Croft. There are two kerbed cairns on either side of the circle that, in former days, would have been large and noticeable, 200yds to the southeast and northwest, and very much part of the Nine Maidens' visual setting in ancient times.
Although this is the bleakest of the four circles, it's lovable, especially if you relax with a flask of tea and imbibe the atmosphere when you go there. It's quite remarkable being there when the fog is down! It has a fine panorama of many of the key hills of West Penwith.
Boscawen-ûn (pr: Boscaw-noon) stands at the intersection of six significant alignments linking it with many major sites: Godolphin Hill, St Michael's Mount, Lesingey Round, Stannon Circle on Bodmin Moor, Gurnard's Head, the Nine Maidens, Lanyon Quoit, Cape Cornwall, Maen Castle, Carn Lês Boel, as well as, on the Isles of Scilly, White Island cairn on St Martin's and South Hill on Bryher. That's serious, carefully-devised, intentional connectivity.
It is precisely positioned in the landscape so that Chapel Carn Brea with its hilltop cairns is framed between two slopes, and a gap or gateway in the stones highlights the hill. The sea is visible southwards at Boscawen Cliff in a narrow window that becomes invisible if one moves just slightly away from the circle, as is the case also with a view of the distant Pipers menhirs and the Merry Maidens. Just above the stone circle is a carn or outcrop called Creeg Tol, a very ancient natural holy site that preceded the stone circle.
The visual placing of Boscawen-ûn in its immediate farm landscape is at first rather unimpressive, and one would be forgiven for wondering why it is there. But the intricate alignment positioning pattern mentioned above suggests not only definite, intentional reasons for choosing this location but also a remarkable act of fitting it all together. How did they figure out all this without aerial photography, helicopters, theodolites and computers?
The quartz stone at Boscawen-ûn
Boscawen-ûn was classified by Prof Alexander Thom as a Type B flattened circle, though actually he was incorrect: unusually it is an ellipse or oval, oriented roughly NW-SE, probably aligned to the rising point of the newmoon at a summer solstice lunar maximum and the setting point of a winter solstice fullmoon lunar maximum. It is 24.9m by 21.9m in diameter - this proportion is probably astronomical too.
Two special features are a quartz stone on the circle's perimeter and a tall inclined stone located off-centre in the circle, pointing northeast up the main axis of the southwestern peninsula of southern Britain. This stone seems to be deliberately leaning as it does, and it has two indistinct axe-carvings in its NE face.
Later, in the 500s CE, in the Welsh Triads, Boscawen-ûn was named as one of the three chief gorsedds or druidic meeting places of the isles of Britain. It was also the very first ancient site in Britain to be intentionally preserved, as a result of a private initiative by a lady from Penzance in the 1860s, who bought it when she heard it was to be demolished.
Circles that disappeared
Many stone circles in Penwith have been destroyed. Those that are known are these:
Boleigh (SW 4314 2444), over which there is some dispute. It was part of the Merry Maidens complex, west of today's stone circle by only 200-300 yards. It had seven stones and was '30 paces' across. It was still surviving when recorded by Borlase in 1740 and it was destroyed in the late 1800s. See also Tregurnow, below, another former stone circle near the Merry Maidens.
Bosiliack (SW 440 320 approx). A 'Druidical circle' was noted by antiquarians but no signs of it have been found.
Botallack (SW 3669 3311). There is no sign nowadays of this rather unique multiple-circled site. It might not have been a classic stone circle, and too little is known of it to judge. Borlase wrote: “Fronting the gate of Botalac town place there is a most remarkable miz maze, if I may so term it, of stones set on end, which if Ducaleon himself had thrown behind his back could not sufficiently stood up in greater disorder than they at present appear, but viewing them diligently this March 6th, 1737, I find the largest circle monument there of any I yet have met with, with several subordinate circles, some touching the circumferences, some breaking within it; together with two large erected stones, not many paces from the principal ring.” The stones were probably used in tin-mining construction in the 1800s. While this might not have been a classic stone circle, it was certainly an interesting structure. Very few ancient site alignments go to it, suggesting that it might not be a megalithic site, and built in later times.
Higher Trevorian (SW 4168 2626). Marked on old Ordnance Survey maps, little is known about this circle, though it is generally accepted to have been there, and some remains exist at the location - though, again, the records and remains are inconclusive.
Mên an Tol (SW 4264 3493). This iconic site, with its unique holed stone, is not what it was in ancient times. The two stones and the much-loved holed stone making up today's Mên an Tol were so erected in the late 19th Century, using stones from the preceding stone circle.
The site currently has three standing and six recumbent stones, plus one possible extra stone, a cairn and the famous holed stone.
Formerly it was a stone circle of probably 19 stones, and it was up to 18m in diameter. This circle was presumably a twin circle to the nearby Nine Maidens stone circle, and it was overlooked by Carn Galva and Watch Croft, with Bosiliack Barrow and other local features nearby - they all formed a local system, with Nine Maidens possibly serving as a sun circle and Mên an Tol as a moon circle. If the holed stone was originally inside the stone circle like the off-centre leaning stone in Boscawen-ûn, then this arguably endows Mên an Tol and Boscawen-ûn with a female and male symbolic relationship.
Rosemergy (SW 4178 3647). Nothing remains of this presumed stone circle near Morvah, below Carn Galva and close to the cliff sanctuary of Bosigran Castle, except some stones removed to the hedge. The site was visited by Meyn Mamvro in 2015 and the exact position found by dowsing. Some people doubt that it was a stone circle - though indeed it was something. Its uncommon location close to the sea is interesting - stone circles customarily do not incorporate seascapes. It lies precisely between Gurnard's Head and Chûn Quoit, and between Bosigran Castle and Watch Croft. It played a part in a wider complex of sites, all overlooked by Carn Galva, including two cliff sanctuaries, Bosporthennis Quoit and Porthmeor menhir.
Treen Common Circle (SW 4445 3665), on Gear Hill, not far uphill from Morvah. This circle has everyone flummoxed. It could be a kind of late neolithic henge, or an unusual one-off bronze age stone circle or an iron age or even medieval enclosure, though it doesn't fit easily into any of these categories and it has never been excavated. It has a few ancient site alignments to it, including one from Gurnard's Head to Mulfra Quoit, suggesting it might have an older, neolithic or bronze age origin. The stones do not have the definite presence and menhir shape of other stone circles in this area. So it is probably not a classic stone circle. It's another something. It might have had some similarity to the circle complex at Botallack, mentioned above.
Carn Kenidjack busy hovering over Tregeseal
Tregeseal (SW 3866 3237). Tregeseal originally had two or three stone circles close to each other, lying below the characterful hulk of Carn Kenidjack. The surviving one, the east circle, has 19 stones and is in reasonable health, though the stones on its western side might have been moved slightly after restoration following tin-mining explorations there.
The other one or two circles have been obliterated - the final remains of the central circle were built into the nearby wall after being removed by a farmer in 1961. Borlase in the 1700s noted ten upright and four fallen stones in the central circle. It is likely that this was bigger than the surviving eastern circle.
The central circle at Tregeseal - Cotton, 1826.
The western circle is marked on old maps but evidence for it is scanty except for crop marks identified in aerial photos, and there is questioning whether it actually was a stone circle. It's possible it was a big platform cairn, like those a mile away at Botrea Barrows, or a circle of cairns.
The Tregeseal complex contains various other cairns and holed stones - more on the next page. The holed stones, ENE of the circle and 250m away, could be oriented stones pointing to parts of the Isles of Scilly. Or they could have some other function - these stones provide more questions than answers.
The presence of the neolithic tor enclosure, Carn Kenidjack, overlooking the complex, suggests that the ceremonial centre of gravity on the tor in the neolithic shifted downhill, first to the neolithic cairns a few hundred yards from the stone circle, perhaps around 2800-2500 BCE, and then to Tregeseal stone circle during the 2500s or whenever it was built.
Tregurnow (SW 4375 2455). This is part of the Merry Maidens complex, a few hundred yards from the Merry Maidens. Its last two stones were broken up only in 2006 (the farmer has since recognised his error). Presumably it had 19 stones, like the Merry Maidens. It might have been more important or older than the Merry Maidens, if its position on the brow of the hill overlooking Lamorna and the wider landscape is anything to go by, but it certainly was a twin circle to the Merry Maidens. We know little more than this.
Stone circle design
As far as we know, all four surviving stone circles contained 19 stones. This indicates an astronomically-related purpose, since 19 stones represent the Metonic Cycle which unites the varying cycles of the Sun and Moon. The Encyclopedia Britannica defines this as:
...in chronology, a period of 19 years in which there are 235 lunations or synodic months, after which the Moon's phases recur on the same days of the solar year. The cycle was discovered by Meton (fl. 432 BC), an Athenian astronomer.
The Merry Maidens
Except that, although Meton gained the credit, the megalith builders knew it at least two millennia earlier!
The Metonic period of 6,939.6 days, almost exactly 19 years, is equivalent to:
- 19 solar years,
- 20 eclipse years (cycles of eclipse positions),
- 235 synodic months (cycles of lunar phases),
- 254 sidereal months (lunar orbits),
- and 255 draconic months (lunar conjunctions with its north node - eclipse-related).
The Metonic Cycle is accurate to the extent that it needs just one day's adjustment once every 219 years.
There was a calendrical and time-counting function therefore to stone circles, whereby different objects could be moved from stone to stone as the years and moons went by. Archaeologically such objects have not been found: this suggests either that they were organic (wood or bone) or that the process was carried out mentally and through memory (consistent with known druidic practice, later in the iron age).
The underlying aim was to act in harmony with the cycles of the universe. Regular rites and ceremonies would be carried out to mark time and to encourage the seasons to move and the conditions of life to be favourable. Reverence was scientific to bronze age people, and technological as well as spiritual.
While they will have had advanced cosmological teachings giving shape to their beliefs, they had practical aims too, aimed at raising the fertility of the land, improving the condition of humans, encouraging fair weather and warding off ill-fortune. It was a manifestation of the perennial aspiration to build heaven on earth.
This 19-year time period was a human generation in length - an apt interval for counting longer periods of time. Most ancient calendars had no start-point as ours does: instead they were counted in terms of generations or planetary cycles, such as the 60-year Great Mutation, a cycle of three Jupiter and Saturn conjunctions.
Every third Jupiter-Saturn conjunction, the conjunction takes place in the same place as 60 years before (plus a few degrees). Successive 20-year conjunctions would always be in zodiac signs of the same element (such as, today, in the air signs Aquarius, Gemini and Libra), and they shift element every 240 years. This fed into a larger cycle of 40 conjunctions lasting 800 years, in which successive conjunctions would return to exactly the same zodiac degree as 800 years before. This provided the basis of a longterm calendar. Just as we say '14th Century', they might say, 'the third Great Mutation of four Grand Cycles ago'.
Boscawen-ûn as seen from the Creeg Tol rock outcrop
One consequence of using 19 stones is that no stone stood exactly opposite another stone in the circle. A stone was thus intended to face an open space between stones on the other side of the circle.
In Penwith, in most cases the stones are flattened on the inside and rounded on the outside, as if acting as reflectors focusing energy inwards into the circle.
In terms of subtle energy a stone circle can be seen as a resonator and an amplifier. Some dowsers have noted a spinning element to the energy field in a stone circle - Tom Graves' cyclotron effect, referring to the analogy of a particle accelerator. The idea here is that, if this spinning is amplified by such actions as visualisation, rhythmic dancing, music and chanting, it would create a strong field within which to work.
Every stone circle is placed on top of a blind-spring, an up-flow or seepage of water from deep down, which then hits an impervious layer. Water is then forced out roughly horizontally under this layer in a radial pattern of springs and seepages underground, creating an energy-field on the surface that clearly interested the people of the bronze age.
Just go to a stone circle, relax and be quiet for a while, and you will find your mood and state significantly changed - generally in a happier direction. This capacity at stone circles for consciousness-shift interested the ancients, and the energy-fields of underground water, enhanced at a stone circle, stimulate that shift.
There is a vertically-oriented containing element to a stone circle, with the vertically-alternating energy-flow emitted by a blind spring under the centre of the stone circle being concentrated and funnelled up and down according to the cycles of the moon, the season and larger cycles. It is entrained through the space inside the circle and through the upright stones, which act as conductors between earth and sky.
The atmosphere at a stone circle is distinct, quite strong and captivating, and it changes at different times. No one has been able to study the periodicities of this. Choose your moment for visiting, and give thanks when it's time to go.
Stone Circle Astronomy
The Nine Maidens or Boskednan stone circle
The ancients weren't fixated on calendrical dates and times in the same way as we are. But they did have an interest in understanding nature's cycles, for practical purposes such as planting and harvesting, for the timing of festivals and rites, and also because they saw themselves as active participants in spinning the wheels of time and season. This was their way of harmonising with the earth and cosmos.
Time has character, quality, meaning and potency. Working with change, time and season to capture and entrain this time power lay at the core of the megalith builders' worldview. To them, astronomy (observation) and astrology (interpretation) were the same thing. They built ancient sites to embody principles they perceived in nature and the universe. They captured time by representing it in mathematical and geometric form in the design of stone circles.
The placing, design, mathematics and orientation of ancient sites were all carefully calculated to embody the eclipse cycle, the anomalistic year, the solstices and cross-quarters of the year, lunar phases and probably longer-term cycles such as the sidereal and synodic cycles of the planets. But we're only a small way into deciphering this.*
The ancients sought to play their part in the fluxings of the universe and the intelligence or the heart of nature - and if they failed in this, they felt things could deteriorate or go wrong. This might seem superstitious, except in our day the cycles and fluxings of the biosphere and climate indeed are going seriously wrong, and we know it, so there's a lesson to learn from this.
They emulated the patterns and cycles of the universe in their ancient sites and rituals. They weren't solely seeking to calibrate their calendars, as many archaeologists would believe. Their calendars were living, breathing, life-determining, religious, scientific things, not just statistical day-counters.
The Merry Maidens
Solar and lunar calendars
The ancients had a double calendar - solar and lunar. The solar calendar was anchored in the solstices and equinoxes, divided into sixteen periods - each quarter of the year being divided into two and four segments.
The lunar calendar was anchored in the lunar phases, particularly newmoons and fullmoons, of which there are around 12.5 cycles per solar year. The lunar and solar cycles are out of sync, though they synchronise with each other once every 19 years.
The solar calendar relates to the seasons of the year (warmth and light) and the lunar calendar to cycles of tides, water levels, light at night and natural fertility. Though the coming of spring or autumn is determined by the sun's cycle, the actual visible changes, when flowers come out or the leaves fall off the trees, when birds migrate and the weather turns, are timed by the moon.
A 19 stone circle thus embodies the integration of solar and lunar calendars, also indicating an interest in eclipse cycles. At the 1999 solar eclipse in Cornwall, it was found by a team of dowsers led by Sig Lonegren and Billy Gawn that, at the precise time of the eclipse, the energy-lines they were monitoring in the earth literally rolled up and declined to zero, only to roll back to full strength as the eclipse ended. It was as if the eclipse was re-booting the energy lines.
Observing these cycles was incorporated into the design of stone circles. The stones were used in counting and calculating, but it had other astronomical virtues too. A neophyte would have to learn exactly which stones lined up with which other stones at the other side of the circle to track the varying rising and setting points of the sun and moon. From one stone it is possible to take a sightline to at least seven stones on the other side, and to at least three positions on each stone (left side, centre and right side) - so we have at least 21 variables to play with, from each stone.
Sites in the surrounding complex would serve a similar purpose. Some menhirs and cairns would serve as foresights for viewing the rising and setting points of heavenly bodies from the stone circle.
The people of the bronze age left no instruction manuals - their knowledge was passed through whispered lineages. We don't understand the full extent of the design principles involved in stone circles. But there are some clues provided by archaeoastronomers and mathematicians. Prof Alexander Thom, an engineer and archaeoastronomer of the 1950s-70s, noticed that stone circles had different shapes - not just pure circles. He identified two main types of flattened circle - a circle where half of it is circular and the other half is pushed in to make a flattened half. These required different complex geometries.
Trouble is, pioneers get some things right and some wrong. In the case of Boscawen-ûn, Thom identified the circle as a flattened circle when in fact it is oval - equally flattened at both sides. Nevertheless, surveying hundreds of circles, especially in Scotland, he established principles of stone circle design that hold true and constant.
Thom's incorrect survey of Boscawen-ûn
Thom showed how the megalith builders had units of measurement which he called the Megalithic Yard (2.72ft). This has recently been reviewed with the discovery of the Megalithic Foot (14.142in) by Harris and Stockdale. All stone circles across Britain are measured in these terms.
Metrology, the science of ancient measuring systems, is complex (introduction here), yet it is one of the most detailed clues for understanding the megalithic mind and the advanced nature of its science. Archaeologists avoid it studiously. (Here's an exception: a video discussion between metrologist John Neal and Oxford Prof Michael Vickers.)
The megalith builders utilised a complex geometry, involving advanced astronomical knowledge which included the size of the Earth and the difference between the polar and tropical circumference of the Earth (since the Earth is wider at the equator than at the poles).
The stone circles were conceptually much more sophisticated than first meets the eye. In them the ancients left a tangible record of their knowledge and science, for posterity. The stone circles also represented microcosmic embodiments of cosmic laws, represented in geometry, measure and proportion. In clarifying the principles of these cosmic laws, the ancients emulated universal principles, bringing heaven, earth and the human world into harmony - something which, in their eyes, presumably aided human fortunes and contributed something to the wider universe. They had rather Taoist attitudes, around two millennia before Lao Tzu wrote them down in China.
This is important in our modern day. Technologies in the 21st Century now need to emulate nature, reflecting its principles, to avoid the polluting and destructive effect of so many modern technologies. This was the underlying message of John Michell, the man who unearthed the importance of ancient geometries and metrology, who also established the first principles of the alignments system of West Penwith in 1972 book The Old Stones of Land's End.