Category Archives: BLOG

Stonehenge & Woodhenge – PART TWO


Megalithic science provides a skill set whereby it becomes possible to understand the long-forgotten rules or lost science needed to fathom out the purpose or function of a megalithic design that has stood there waiting to be understood for thousands of years. This experience can confer an awesome sense of privilege, and it can connect a researcher directly to their far distant roots, seeing into the mindset of their ancestors. Once a few and quite simple rules are understood, the design rules, astronomy, units of length and geometry originally applied by the original architect(s) and/or builder(s) of a megalithic monument can be revealed. This methodology is presently and sadly not recognised by mainstream prehistoric archaeologists.

The various techniques and methodologies by which this recovery process is brought about has been described in many of my books and articles, and in many other works by relevant researchers in this field.  The experiences which led me to be able to write on this subject are perfectly crystallized below, when I began investigating the relationship between Stonehenge and Woodhenge.

Measuring the Distance between Stonehenge Centre and Woodhenge Centre

In Part One a single action began the process of investigation. I made a measurement of two physical realities : firstly the length of a line connecting Stonehenge centre to Woodhenge, centre, and, secondly, the angle of orientation that this line makes with respect to an east-west line, termed a co-azimuth angle. This second part of the article shows where that single action can lead a researcher into understanding presently unsuspected purposes within the designs of, in this case, Stonehenge and Woodhenge. A set of functions are revealed, functions or purposes which presently, no other technique being applied by archaeologists can offer.

I had measured the distance between these two henge monuments previously, and even the angle, in 2003, during the writing of The Measure of Albion (Bluestone Press, 2004, co-authored with John Michell (a facsimile is available in the USA under the title The Lost Science of Measuring the World, 2006, AUP). At the time this data became buried with a mass of other material had been gathered at the time. I had derived the length from the OS map coordinates, and this has since become the quaintly old fashioned way! Google Earth arrived soon after 2003, providing an astonishingly useful tool for this kind of work, although it can be fraught with dangers in this work unless backed up with site work on the ground. Google Earth, like the map, is not the territory. (adapted from Alfred Korzybyski, with apologies!). Researchers will need to recognise that the model of the earth (The Geoid) used by the British Ordnance Survey in making maps of Britain is coded OSGB36, whereas Google Earth uses WGS84 (World Geophysical Survey 1984.) Conversions from one system to the other are available on the web.

The 10033 feet measurement shown in the illustration above was taken centre to centre, using Google Earth.  For Stonehenge, the centre was assumed to be that location where the diagonals of the 5:12 station stones rectangle cross each other. The corners of this rectangle were originally occupied by moderately large stones. They were set a few inches inboard of the Aubrey circle perimeter and asynchronous with its hole spacing (see diagram below).

More detail: Stone 91 now lies recumbent next to its original stone hole and stone 93 is a large solitary stump over to southwest of Stonehenge. There are two missing stations, 92 and 94, but fortunately the location of their original holes has been established (Atkinson, et al). The centre of the Aubrey circle, marked as explained above, is depicted below, on a useful diagram that also indicates the principal solar and lunar orientations at Stonehenge and the direction of Woodhenge centre, which remains clearly marked by a solitary drab concrete bollard.

Stonehenge centre to Woodhenge centre = 10033 feet ( ± 3 feet)

It is estimated that this measurement, from centre to centre, is accurate to better than plus or minus three feet of the value given above.

Maxing the Factors

Now look what happens when one discovers the component factors present within this number,

10033 (feet) = 13 x 283.6 x 2.722 

The number 10033 feet can be represented by a tryptych containing three relevant numbers, each familiar to a student of megalithic science.

A).The number thirteen is inherently the numerical signature of the longest side length (hypotenuse) of a 5:12:13 triangle. 

B). The number 283.6 is the mean diameter in feet of the Aubrey circle, established by professors Alexander Thom and Richard Atkinson, during their 1973 survey of Stonehenge. Each Aubrey hole was located by Atkinson by probing and resistivity testing, and its centre established and marked with a survey pin (Thom & Thom, JHA, 1974, op cit, see Part One). 

C). 2.722 is the numerical value of the megalithic yard in feet, a unit that was originally discovered by Alexander Thom following two statistical methodologies prepared by the top Oxbridge statisticians of the time and based on analysis of the diameters of over 150 stone circles. (see Thom, MSIB, 1967, Chapter 5, and Thom & Thom, MRBB, 1978 , Chapter 4)

The point to point measurement of 10033 feet is also associated with an angle so similar to that of the apex angle of a 5:12:13 triangle that it may reasonably be  assumed to have been intentional, part of whatever process of laying out the bearings from Stonehenge took place, prior to Woodhenge’s construction. This tends to support the present archaeological view that Stonehenge was the first of these two henges to be erected.

But did Stonehenge come first? This is an important question that must not be hurried in the answer. The earliest known structures in the immediate Stonehenge landscape are those three massive post holes which incongruously became known as the ‘car-park post holes’ during the 1970s building of the now defunct earlier Visitor’s Centre and tunnel. Their locations were eventually marked with large white painted circles of concrete.

Whether the Woodhenge site may or may not have been later adapted throughout its long history, it remains true that the earliest known building work on this henge site included some very large post holes.The post holes for Woodhenge indicate that the posts would have been extremely massive, requiring similarly large retaining holes, particularly if the assumed wooden posts were long enough to support a roof structure. Evidence exists, for Cunningham’s excavators indeed found that there were ‘deep ramps to all the holes in Ring III‘. Thom also states (Thom, MSIB,1968, p 75) that ‘if the posts were 2.88 ft (in) diameter the inside of the structure would be a perfect fit‘ (to the sequence of perimeter lengths, discussed in Part One).

But what if those sixteen holes in Ring III were originally not intended for wooden posts? It is by no means a done deal that they were, is it? Their diameter is well matched to many of the eighty or so bluestones that remain on the Stonehenge site today. Might Woodhenge have once housed a bluestone circle during the five centuries gap that currently haunts researchers into the origins of the bluestones. Woodhenge has been somewhat neglected over the years, a wooden Cinderella to its stoney sister, Stonehenge. Viewed sideway on, at ground level, it may resemble a load of bollards, but Thom’s surveyed plan (and Part One and the diagrams here) suggest that Woodhenge is far more interesting than that.

The Unit Length of a Triangle

For any size triangle laid out in two dimensional space, the unit length can be found by dividing the measured length of the perimeter, in any chosen unit of length, by the number of ‘units’ in the perimeter. For a known and accurate 5:12:13 Pythagorean triangle, the perimeter units total thirty, the sum of the side lengths [13+12+5]. For the triangle under investigation, the perimeter length totals 23,153 feet and the unit length becomes that value divided by 30, (see below).

Because the apex angle is negligibly different to that of a 5:12:13 triangle, the unit length can also be derived simply by dividing the 13 side length by 13. The answer assumes that the 5:12:13 triangle is exact, and geodetic triangles laid out on the ground are never exact. In this  example, on flat territory and over a small area, one would expect the unit length derived from the 13 side alone to be extremely closely matched to that derived from the total sum of all three lengths of this triangle, measured along the ground.

The two side lengths shown in red (on the diagram above) were measured using Google Earth. As an exercise, the reader may like to determine the difference between the unit length derived from the ’13” side alone and that determined from separate measurements taken of all three sides using Google Earth.

There is no substitute for being on site. Walking around this location shows that there is no surface sign that a right angle for this triangle was ever permanently marked, or monumentalised directly, although its location is strongly suggested by the geometry and metrology. A good place to dig, perhaps, but not, not ever, by other than qualified archaeologists who have the required blessings of EH and WHO.

For this example,  the best estimate for the unit length is that derived from the ’13’ side alone. The 13th part of that length separating the centre of Stonehenge from the centre of Woodhenge becomes the unit length of the triangle, in whichever unit of length one chooses to measure it with. In feet it is the product of 283.6  and 2.722 , which is 771.77 (feet).

Unit length of the ’13’ side of the triangle = 771.77 feet

But this is also 283.6 megalithic yards (771.77 feet / 2.722 feet), numerically the mean Aubrey Circle diameter expressed in the larger unit of the megalithic yard, instead of the 283.6 feet (mean diameter) of the Aubrey circle. The three factors revealed above can now reduce to just two, and the length 10033 feet is seen to contain 13 lengths of 283.6 megalithic yards.

The 10033 feet distance connecting Stonehenge (centre) and Woodhenge (centre) is thirteen super-Aubrey circles… (if you like)!

10033 = 13 x 283.6 megalithic yards

The Perimeter Length  

The perimeter of a 5:12:13 Pythagorean triangle can be estimated by multiplying the length of the 13 side by 30/13, as shown above. This delivered 23,153 feet or 8,505.9 megalithic yards. The perimeter may also be measured using Google Earth for each of its three sides, and this presents an identical length, at 23,153 feet.

In Part Three, the consequences of this research will make it possible to recover yet more useful information from the designs of Stonehenge and Woodhenge, taken together. And we will take a journey to the Preseli Hills of West Wales, where interest extend way beyond those outcrops that have proved to be the source of many of the Stonehenge bluestones.

Additional Notes : It is fortunate in this work that the foot and the megalithic yard have remained clearly defined and recogniseable units of length. Thom’s megalithic yard became recognised during modern times in Megalithic Sites in Britain (Oxford, 1967). Metrologist John Neal, in various metrological publications from 2000 onwards, proposed that the megalithic yard should more correctly have been named a megalithic step, being 2.5 times the length of the foot from which it derives within the traditional system of metrology, and not three times that length (a yard).

Neal identified the foot from which the megalithic yard derives to be the Geographical value of the Belgic foot (1.08617 feet). The root value of the root Belgic foot holds a ratio of 15:14 with the ‘root’ value of the English foot.

Similarly, Thom’s megalithic fathom (5.44 feet =  2 megalithic yards) would be better termed a pace, but Thom’s megalithic rod, (6.805 feet = 2.5 megalithic yards) sits comfortably within the canon, because a rod can be a double royal cubit, here based on a royal cubit whose single length is 3.403 feet.

In comparison, the inner and outer diameters of the sarsen circle accurately measure 28 and 30 double royal cubits at geographical value (3.4757485 feet), respectively.



Robin Heath, December 2017                      StoneAgeSurveys           





Stonehenge & Woodhenge – A Lost Legacy – PART ONE


Soon after the distinguished Welsh archaeologist Maude Cunningham and her husband finished work excavating the site we now know as Woodhenge, in 1929, the locations of each of the site’s many revealed postholes were marked with grey concrete bollards. The best that can be said of this action was that it ensured their original exact positions were recorded for posterity (see Alexander Thom’s photograph below, from 1958, courtesy of Eoghann MacColl).

Visually, Woodhenge is neither a pretty nor an impressive site, unlike its nearest neighbour, Stonehenge, some 1.9 miles to the southwest. VIsitors to Woodhenge tend not to linger around this site, and soon slope off to nearby Durrington Walls, to the north, or Stonehenge, to the southwest. This article claims to lift the present Cinderella status afforded to this Neolithic class II henge and timber circle monument, by identifying a previously unrecognised significance in its geodetic placement with respect to Stonehenge.

 The Brief History of Woodhenge’s Discovery

Originally, what became Woodhenge was first discovered in modern times during the first half of the nineteenth century, as ‘earthworks’ thought by some archaeologists of the time to be a disc barrow. It had been named Dough Cover, surely the first reference to the site’s henge shape.  In 1926 Woodhenge’s discovery was amongst the first triumphs of the new science of aerial photography, and the site was first positively identified from an aerial photograph taken by Squadron Leader  (later Group Captain) Gilbert Insall, VC, in 1926, during a survey of Wessex by Alexander Keiller and OGS Crawford.  Keiller later undertook the pioneering restoration work at Avebury, during the 1930s, and Crawford was Archaeology Officer for the Ordnance Survey and later became the editor of Antiquity. Having recognised the importance of the site,  renowned archaeologists Maud and Ben Cunningham immediately began work excavating the site, and by 1929  their survey report confirmed that it was indeed a henge.

In 1958 and again in 1973, Alexander Thom undertook a survey of the Woodhenge ‘bollards’,  a simplified version of his original plan of the site appearing in Megalithic Sites in Britain (Oxford, 1967, p74) site. His original site plan is reproduced below.

Thom wrote that a ‘very careful survey’ of the site, ‘using steel tape and theodolite, was made of the concrete posts which the excavators placed in the post-holes in the chalk’. He then linked the site with Stonehenge astronomically by  pointing out that the axis of the site aligns to ‘the point on the horizon where the midsummer sun first appeared about 1800 BC’.

The calculated ‘first flash’ azimuth is indeed 49.2 degrees when the given figures for the latitude of the site and horizon altitude are entered into the standard formula (see below).

A hawk-eyed reader may spot that on the plan published in MSIB  the solstitial sunrise is given a declination of 24.2 degrees, which corresponds to a date around 4800 BC, far too early for all dating estimates of Woodhenge.  The original plan (above) gave the declination in Thom’s own handwriting,  at 23.9 degrees, and a theodolite measured horizon altitude of 0.5 degrees. 


QUICKAZ – Finds azimuths in a flash!

1. Determining solstice sunrise at Woodhenge, circa 1800BC (dec 23.9 degrees)

The proposed sunrise is in the NE quadrant.

Epoch 1800BC, Declination = 23.914, Latitude = 51.2, Horizon Altitude = 0.5 degrees

Correction for Earth’s Curvature = 1.37197E-06, Parallax Correction = .002 degrees,

Refraction Correction = 0.55 degrees

                                                          ^         ^         ^

********- horizon -****^****^****^**********

First Flash =                              49.20144 degrees

disc half risen =                                49.61157 degrees

disc on horizon =                                   50.42171 degrees

The same formula run with 24.2 degrees declination (4,800 BC) give the following rise azimuths for the sun:

2. Determining solstice sunrise at Woodhenge, circa 4800BC (Dec 24.2 degrees)

                                                               ^       ^       ^

********- horizon -****^****^****^**********

First Flash =                             48.64856 degrees

disc half risen =                                    49.06212 degrees

disc on horizon =                                             49.8788 degrees


Program by Robin Heath, Stone Age Surveys, 28th November 2017

The geometry of Woodhenge is shown to be one of a family of designs which mostly occur on the western side of Wales (Castell Mawr and Hirnant), and in Brittany. The various arcs are struck from the points of a triangle, usually of integer side-lengths and Pythagorean (right angle triangles). Sometimes the ‘blunt end’  is semi-elliptical (Castell Mawr) rather than semi-circular (Woodhenge). The plan of Woodhenge given above shows the design to be based around a 12:35:37 Pythagorean triangle, from whose corners the various arcs are struck to define the perimeter. The arcs at the blunt end share a common centre at A, whilst those at the sharp end share a common centre at C. The measured distance between  A and C is 6 megalithic yards (2.72 feet), which makes the triangle 12:35:37 in units of half a megalithic yard.

From point B the flatter arcs are struck to then complete the perimeter.

Woodhenge consists of a set of concentric arcs struck from each point of the triangle, with one gap (see plan). It is the perimeters which reveal the true nature of the design. While the radii are not integral multiples of the megalithic yard, the perimeters turned out to be of lengths close to 160, 140, (gap), 100, 80, 60, 40 megalithic yards. For each ring the radius of the arc at the ‘sharp end’ is 1 megalithic yard smaller than that struck from the ‘blunt end’ (MSIB Table 6.5 shown below, author’s commentary in brackets).

Ring           Perimeter (My)          R1(My0         Major axis    P(actual)

I                      160                            24.02              53.04          161.0

II                     140                            20.84              46.67          138.2

III                    100                            14.47              33.94          104.2

[The same perimeter as the Aubrey circle diameter 283.6 feet = 104.188 feet]

IV                      80                             11.29             27.58            79.9

V                       60                               8.10             21.21            61.3

VI                      40                               4.92            14.84             39.4

Thom noted that there were deep ramps to all the holes of ring III, and that the holes averaged at 2.88 feet diameter (7.839 feet). He concluded that very large posts had been used, ‘carrying perhaps a platform or roof‘ [or maybe a bluestone or two?]. He further noted that the ring was 4 per cent larger than expected, and that holes of the above larger diameter would assure ‘the inside of the structure would be a perfect fit‘.

Neglecting ring III, Thom applied his statistical methodology, designed by mathematician and statistician Dr Simon Broadbent, to find from the values of P(actual), the value of the megalithic yard which best fits Woodhenge. This turned out to be about 2.718, a value so close to his later value for the megalithic yard ( 2.722 feet) as ‘to show that we can be quite certain we are using the identical geometrical construction to that used by the builders‘.

To briefly digress, when I was staying with the Thom family in preparation for writing the biographical account of Thom’s life and work (Alexander Thom: Cracking the Stone Age Code, Bluestone Press 2007) the full nature and extent of the excoriation this pioneering archaeoastronomer had endured from the negative reaction to his work from many mainstream prehistorians and archaeologists was laid bare in front of me. This became known within archaeology as ‘Thom bashing’ and ‘Thomfoolery’. However, some of the leading prehistoric archaeologists of that time (Atkinson, Burl, Case, MacKie) were both amicable and quite accepting of his work and studied the implications of accepting the claims Thom had made concerning the capabilities of Neolithic megalith builders. What was also painfully true was that many of his most vehement critics were neither equipped nor qualified to assess the numerical nature of Thom’s findings. Interested readers can glimpse the nature of this energetic debate – a fascinating vignette of a true pioneer who arrived on the scene during the most turbulent time in the recent history of archaeology – by watching the archived 1970 BBC ‘Chronicle‘ documentary, Cracking the Stone Age Code,  available on the web (search ‘BBC archive Chronicle Thom’). They do not make documentaries like that any more.

What happens when Stonehenge and Woodhenge get together

Thom first surveyed Woodhenge in 1957-8 while he was still professor of Engineering at Brasenose College, Oxford. By the time of the 1973 Stonehenge surveys he had retired and moved back to the family farm (The Hill) in Dunlop, Ayrshire. He enjoyed full assistance during that work from his son, oceanographer Dr Archibald Thom,  professor Richard Atkinson, Stonehenge custodian Major Lance Vatcher and members of the Survey Branch, Royal School of Artillery. His report first appeared in the Journal for the History of Astronomy, Vol 5, part 2, No 13, June 1974), and a version of this paper later appeared in Megalithic Remains in Britain and Brittany (Thom and Thom, Oxford, 1978).

It  dawned on me while working on the relationship between Stonehenge and Woodhenge that Alexander Thom is probably the only individual who has ever undertaken an accurate survey of both monuments. I was particularly aware of this during a trip to the Stonehenge landscape with John Michell in 2003. While setting up a theodolite on an anonymous barrow some 3700 feet from Stonehenge, I noted that all three sites lay on a straight line connecting Stonehenge with Woodhenge. When I returned in 2014 (with a better theodolite) I had more time to study this linearity and its relationship with the sky and landscape.

The centres of the two henge sites are spaced 10033 feet apart. Defining the centre of Stonehenge is rather harder to estimate than for Woodhenge, due to each phase of the former monument having a slightly different centre than the others (Thom, JHA 1974, op cit). I used the crossing point of the two diagonals of the station stone rectangle, as shown below ( lower left). The measurement is from Google earth, and estimated to be accurate  to within two or three feet, based on a normal surveying practice of defining a previously laid out base line, in this case the measured distance between the eponymous Cuckoo stone and Woodhenge centre, some 1350 feet in length, and using Google earth to compare the accuracy of that already known length with the length delivered by GE for the unreachable (out of bounds) centre of Stonehenge!

The azimuth or bearing of this line, looking from Woodhenge to Stonehenge, is 247 degrees and  23 minutes, obtained from a sun-shoot. Looking up the line from Stonehenge, this azimuth angle (the angle between north is 67 degrees and 23 minutes’, and the angle from the white east-west line (illustrated above) is therefore 22 degrees 37 minutes). This is significant, for it is uniquely the acute angle of a Pythagorean 5:12:13 triangle. It means that the two thin white lines above, each aligned to the cardinal points of the compass, for the ’12’ side and the ‘5’ side of the triangle, and have lengths, according to Pythagoras’ theorem, of 9261 feet and 3858 feet respectively. There is no sign of any monument at the point where these lines meet, at the right angle, although a dig there may prove fruitful for anyone up for the task and who has permission from the custodians of this World Heritage site!

Here’s where the application of megalithic science begins to deliver big dividends. There has so far been no digging, no invasion of the site, no massive expense and yet already this investigation is able to change the way we look at these two henge monuments, separately and as a pair. And there has been neither the harming of any archaeologists, nor employment of loony fringe ideas. Just one angle and one length accurately measured using precision instruments up to the task.

There is already an existing 5:12:13 triangle implied within the 5:12  station stone rectangle, once described by Aubrey Burl as ‘near perfect’. The diagonals of this construction are 13 of the same units that make up the known and measured ‘5’ and ’12’ sides, and the three measurements are 108.8 feet  261.2 feet and 283.6 feet, respectively. It is the 13 side of a 5:12:13 triangle that is our measured length from Stonehenge to Woodhenge,  measured as 10033 feet.

As they say on the sport news, look away now if you don’t want to see the result.

Now for the good bit –  10035.47 feet = 283.6 x 13 x 2.722 feet.

Alternatively 13 x The Aubrey circle diameter (in feet) = 3686 megalithic yards

[99.98% of the measured value, using the later value for the megalithic yard determined by Thom during the 1973 Stonehenge survey (Thom, JHA,1974, op cit) and then the Avebury survey of 1975 – 6, (Thom & Thom, MRBB 1978, op cit, pp 36-43)].

Thus it appears, based on this first step in investigating the relationship between Stonehenge and Woodhenge, that these two henges relate to each other, through a fundamental measurement of the Aubrey circle, namely its mean diameter (Thom, 1974, JHA, op cit), which is fundamentally and intelligently incorporated into the distance that separates their two centres.

That is enough for the first part of this article. Result.


Robin Heath                                           StoneAgeSurveys                                       3rd December 2017







Interesting Factoids about Avebury + free PDF download.

Ten Interesting Factoids about Avebury

1. Avebury is the largest known stone circle anywhere, with a surrounding ditch and bank a mile in circumference

2. The centre of Avebury is placed 4/7ths of the distance between equator and pole, at latitude 360/7*

3. A very detailed and accurate seven station closed traverse survey was undertaken by Professor Alexander Thom in 1978.

4. Thom reported that the perimeter of the outer stone ring was 1302.5 Megalithic yards (MY) of 2.722 feet, which is 3545.4 feet or 520 Megalithic rods ( 1 MR = 2.5 MY).

5. The geometry of the ring is based on a circle 200MY in radius (544 feet/ 1.66m) with centre at point D, exactly 60 MY from C (see diagram above).

6. A 3-4-5 pythagorean triangle ABC of side lengths 30-40-50 MR (75, 100 and 125 MY) defined much of the geometry. From the corners of this triangle (the stones/markers have long gone) three of the various arcs that make up the outer ring were struck. Their radii and arc lengths are as follows:
From A, B and C, each radius 260 MY, define arc FG, from A, arc HG, from B, and arc ML, from C.
In addition, there were two longer arcs struck from outside of the ring, of length 750 MY, from points W and Z (not shown on diagram). The remaining part of the perimeter is based on the forming circle perimeter, whose diameter is 200 MY..

7. The two inner circles are each 125 MY in radius and are therefore as big as any other true circle known in Britain, and the same size as the massive Ring of Brogar in the Orkneys.

8. Avebury, unlike nearly all other stone rings, has CORNERS, which demarcate the arc lengths. Thom
showed that all the arc lengths are integral in Megalithic rods, and total 1302.5 MY (521 MR)

9. Avebury is a MESS. The ring was heavily vandalised in history, has a village built within and
without it, and a major road system has quartered it (see piccy below). Most of the stones were fallen
or missing in 1930. Only nine still stood. Despite this, Alexander Keiller and other archaeologists were able to locate the majority of the remaining stone holes in the chalk and restore much of the original monument, The geometry of the original ring has since been discovered by AlexanderThom.

10. When built, the outer stone ring contained either 98 or 99 stones, some weighing over 50 tons.

AVEBURY TOUR (compressed) 2017 PDF file of full report.

Equinoctial Stone row alignment (photo)

Three yonking great stones that mark to the Equinoctial (west – 270*)) sunset, part of a section of the Dinas Cross to Pontfaen road in the Preselis, near Russia (’tis true!), where the road markedly changes direction and follows the alignment for about 470ft (170m). Two of remaining three upright stones are those stand in front of the sun’s disc in the distance. All other stones are now recumbent, and lie buried in the bank, just as one finds at the minor standstill moonset ‘detector’ (301.4*) at Parc y Meirw (Field of the Dead) on the Llanychaer road, about a mile away. Prehistoric precision astronomy at its best in Preseli!

For nearly ten years I have had to wait in order to capture the sun’s disc located at the end of this alignment during its setting moments on the day of the spring equinox. For more details, avail yourself of a copy of Bluestone Magic, a Guide to the Prehistoric Monuments of West Wales – as these sheep clearly did – page 56 and elsewhere, which contains colour photos and explanatory text about these two robust alignment sites.


Book Review of Temple in the Hills

Hello Robin,
I thoroughly enjoyed Temple in the Hills, and many others will enjoy it also. Your excellent surveys are really the key to convincing archaeologists of the broad scope of ancient science and knowledge. I have attached a short review and do firmly believe that we should encourage students to follow your footsteps in metrological surveys so that more people may convince themselves of these essential sciences.

Best Regards and Thank you again for your inspirational book!

Thomas Karl Dietrich is the author of Temple of Heaven & Earth, Culture of Astronomy, and Origin of Culture. websites: and

Here is his review:


TEMPLE IN THE HILLS, The Discovery of the Original Stonehenge by Robin Heath

The introduction to Temple in the Hills by Robin Heath traces olden traditions and modern movements concerning the bluestone circle at Stonehenge, Zodiac hunters, New Age celebrities such as John Michell and Alexander Thom. The main corpus is dedicated to a review of astronomical phenomena and especially Heath’s discovery of the ‘Lunation Triangle’ within the context of ’the 30-segment, marked rope & peg’ configuration producing the 5-12-13 triangle which numerically defines the Moon’s relationship with Sun and Earth. Heath also gives a basic primer upon how to construct an accurate Equilateral Triangle on the landscape; again by simple rope & peg implements, showing that detailed, large-scale surveys may be achieved with very simple tools –proving that complex constructs were well within the abilities of our Stone-Age ancestors.

Robin Heath brings a solid case of evidence in favor of Neolithic metrology into the courtroom of archaeology. The evidence turns upon his measurements and discovery of ‘the Preseli Wheel’, centered upon the 500 foot diameter henge at Castell Mawr. Heath delineates five spokes of this wheel: Llech Drybedd, Carningli Summit, Foel Feddan, Carn Menyn, and Foel Drygarn which each average 18,630 feet (3.52 miles) upon the Preseli circle. The evidence of this wonderful precision is an indictment of modern archaeology’s continuing neglect to embrace and acknowledge metrological data and refined astronomical alignments. Heath returns to one of his 2010 investigations of his survey of the Preseli Vesica showing the distances between five locations upon a diamond pattern of two base-to-base equilateral triangles. The length of the common base and the sides of these two equilateral triangles show a nearly equal length and a mean distance of 11,759.0 feet demonstrating; in the author’s own words, “An accuracy that showed it to be a surveyed structure.”

Heath’s detailed demonstration of these irrefutable similar dimensions at the Preseli Wheel and Preseli Vesica represents no small contribution to science –because every well-documented opus elevates and substantiates the case for large-scale Neolithic metrology, precision alignments, as well as the broad based canons and traditions involving cycles, numbers, and geometry. It is absolutely important to celebrate this achievement for what it has and will accomplish. But, rather than bemoan the slow acceptance of new scientific data, I am quite sure that colleges and universities would take up such an interesting project for their students to gain valuable expertise in metrology; namely, to confirm Robin Heath’s survey measurements. This would once and for all guarantee the acceptance of accurate large-scale metrology in the Neolithic period and ignite a fire under the dragging feet and torsos of the archaeologists.

In his conclusion, Robin Heath presents the initial stages of his paramount discovery that the Aubrey Circle and the Sarsen Circle of Stonehenge bear the same relationship to one another as do the Preseli Wheel and its central circle around Pentre Ifan and Eglwyswrw. This correspondence shows that Stonehenge was based upon the template of the Preseli Wheel in Wales dated between 3200-3800 BC. Heath notices that genetic biologists conclude that the brain capacity of humankind has been more or less the same for almost 200,000 years.    TKD

To purchase a copy of this book, and to see a Bibliography of works by Robin Heath, go to the BOOK category on this website.


Those Old Preseli Blues

An excerpt from Temple of the Hills – The Discovery of the Original Stonehenge

 by Robin Heath, Bluestone Press, 2016

Long lodged in folklore and myth there runs an ancient Welsh tradition telling of an original bluestone circle in the Preseli region of west Wales. The matter was referred to in The White Goddess, a seminal work by the Irish academic historian and poet Robert Graves (Faber, 1948),

It has been suggested that the smaller (bluestones) stones, which are known to have been transported all the way from the Prescelly Mountains in Pembrokeshire, were originally disposed in another order there and rearranged by the people who erected the larger ones. This is likely, and it is remarkable that these imported stones were not dressed until they were re-erected at Stonehenge itself.’

However, this tradition goes back much further than recent times, in essence the tradition is about a bluestone circle being uprooted from Preseli and taken in antiquity to Stonehenge,  then reassembled as part of the monument that has stood on Salisbury Plain for at least five millenia, mute, magnificent and yet, above all, mysterious. And despite centuries of attention from all manner of specialisms, the purpose of Stonehenge still remains unclear. This monument’s many secrets and its extant bluestone circle still tantalize and taunt those who attempt to understand the history and purpose of this unique monument.

Unexpectedly, one might think, professional archaeologists are presently taking this tradition seriously, as if it were a prehistoric fact, and are combing the Preseli Hills in an attempt to discover the original location of this alleged bluestone circle. Why would they do that?

Why Preseli?

The archaeologists are the latest activity that feeds the bluestone tradition, adding to it more stepping stones across the wide river that separates Stonehenge fact from Stonehenge fiction. As for many other traditions, their recent activity is neither new nor is it unexpected. This mythic territory and this sacred landscape have both been visited before.  But there are several good reasons why the Preseli hills have become the hot spot for this bluestone circle treasure hunt, the most important being that this landscape’s connection with Stonehenge has been greatly reinforced during the past century.

In June 1903, a geology professor called William Judd scrutinised the implications of the tradition in an article for The Wiltshire Magazine His scientific account of that year listed the difficulties that could be expected in attempting to transport bluestones from ‘a distant locality’ to Stonehenge. He also noted that the bluestones had been shaped and polished at Stonehenge after having been transported, forming the so-called ‘bluestone layer’ of chippings around the monument. Judd made the following astute comment,

The old tradition concerning Stonehenge is that it consisted of a circle of ‘bluestones’ which had acquired a certain sanctity in a distant locality, and had been transported from the original home of the tribe. If so, the stones, brought from so far away, would have been reduced to something like half their bulk…

Is it conceivable that these skillful builders would have transported such blocks of stone in their rough state over mountains, hills and rivers (and possibly over seas) in order to shape them at the point of erection?

Professor Judd did not link the source of the bluestone circle as being in the Preseli region. In 1903, that source was not known for sure, and nobody then could be certain where the ‘distant locality’ of that original bluestone circle might have been. This remains essentially true today, although within two decades of Judd’s work, much stronger evidence was produced to support why the bluestone circle at Stonehenge might have once been located in the Preseli Hills, even where it might most likely be found.

In 1923, a bright light was shone on what had previously been a rather nebulous tradition. Another renowned geologist Dr Hubert Thomas wrote the first scientific paper that supported a connection between the Preselis and Stonehenge. Thomas undertook a petrological analysis of the bluestones found at Stonehenge, enabling a crucial breakthrough to be made. The evidence suggested that these bluestones had almost all originated from a small collection of outcrops along the main ridge of the Preseli Hills, most notably the outcrops around Carn Menyn, a mile or so from Foel Drygarn, at the eastern end of the main Preseli ridge.


If there had ever been a bluestone circle installed in the Preselis, as the tradition suggested, Thomas provided good evidence to back up that possibility, and indirectly identified its location. His work forged a geological link between the Preselis and Stonehenge and although Thomas’s work had not directly mentioned the location of any bluestone circle, his paper undoubtedly was suggesting that were there ever such a monument, it would likely have been located near to Carn Menyn.  In other words, Thomas had confirmed scientifically that an original lost bluestone circle could certainly be a possibility, and indirectly had suggested where it might best be found.

Thomas’s work represented a major breakthrough in understanding the origins and purpose of Stonehenge. It carved through many of the Dark Age and medieval elaborations of the original tradition, but it left untouched another story, linked to the 6th century Merlin, who told that the bluestones arrived at Stonehenge from the Wicklow hills in Ireland, by giants, and had been shipped over the sea on rafts, by giants who assembled them into Stonehenge. This variant of the original tradition was made very popular by the twelfth century chronicler, Geoffrey of Monmouth. His popular fourteenth century romance was later embellished, this famous artwork showing a giant placing a lintel onto a waiting megalith in order to complete the sarsen circle at Stonehenge.


Unfortunately, the geology is all to pieces here, for these are sarsen stones being depicted in this cartoon illustration from the period, not bluestones from Ireland or from anywhere else. The bluestones at Stonehenge are all much smaller than the incredulous mortals shown here watching the giant’s superhuman (and mechanically impossible) feat. However Geoffrey of Monmouth’s story does at least involve a sea journey during the transport of the stones.

Allegedly born in Carmarthen, an old Roman sea-fort less than 15 miles from the Preseli Hills,  Merlin was brought up in that part of Wales two centuries after it had become an Irish colony, within a large part of southern and western Wales that spoke Irish. Whoever created this story, perhaps it was the late fifth-sixth century wizard, Merlin, who may have thought west Wales was Ireland!

This all becomes rather irrelevant however, simply because this tall story is not referring to the bluestones, but instead to the much larger sarsen stones, else Merlin’s giants would have come over as wimps and his story unlikely to impress anyone, for the average bluestone is a tenth of the size and weight of the mighty sarsen stones found at Stonehenge. Then as now, most people visit Stonehenge to see the sarsen circle and the trilithon horseshoe, the central part of the monument. It has been the logo for Stonehenge for a very long time.

There is also the not insignificant factor that no one can be certain whether Merlin actually existed or was simply a legendary folk hero. The Merlin story thus fails to convince as a credible explanation of the source of the bluestones at Stonehenge. However the narrative does link Stonehenge to a source of megalithic stones to the north-west of the monument and suggests they were transported by ‘giants’ rather than glaciers, and that the journey involved a sea passage. Geoffrey’s yarn is part of Stonehenge’s history, but it’s foggy message is confusing and gets us very little nearer the source of the tradition of a bluestone circle being moved to Stonehenge.

The Preseli Zodiac

During the 1970s an apparently new Preseli tradition concerning an ancient circle in the Preselis was placed into popular consciousness. This was a claim made by a group calling itself by the acronym IGR (Institute for Geomantic Research) for the existence of an ancient Preseli landscape zodiac. Just as was the case for the bluestone circle tradition, the idea of a prehistoric British landscape zodiac was anything but new, the concept permeating through the works of Taliesin and other great Bards. Welsh history does not go back much further than Taliesin.

Much more recently, in 1809, Welsh author Edward Davies published Mythology and Rites of the British Druids, which contained a powerful statement concerning the significance and purpose of landscape temples,

As the Britons distinguished the Zodiac, and the Temples or Sanctuaries of their Gods, by the same name of Caer Sidi, and as their great Bard Taliesin blends the heavenly and the terrestrial Sidi in one description, we may presume that they regarded the latter, as a type or representation of the former.’

The two component words that make up Caer Sidi, have a duplex meaning in Welsh, they refer to both the celestial zodiac and to temples consecrated to the ancient British gods. These two words are worthy of a better understanding. In Spurrell’s Welsh-English Dictionary of 1850, Caer is listed as meaning a wall, fortress, castle, fort, citadel, city. The milky way is cited as being Caer Gwydion, often known as Arianrhod.

The root sid- is clearly connected with spinning, weaving, rotation or wheels, and the list of words using this prefix is long. Sidell – fly-wheel; winder; whirl; whorl; rim of a wheel. Sidelliad – revolution; rotation. Sidellu – to whirl; to revolve; to rotate. Siddelydd – winder. Sidydd – zodiac.  Sidyll – whirl; twirl; whorl; rim.

From this Welsh term to describe the celestial zodiac comes an important realisation. Any ancient British monumental circular structure is implicitly going to be a representation or reflection of the sky above, a celestial clock-face, a year-circle and a temple, a manifestation of As Above, so Below, as expressed in one of the tenets of the Emerald Tablet of Hermes, which may date from the seventh century, of similar age to the period of Taliesin.

That which is above is from that which is below, and that which is below is from that which is above, working the miracles of one*.’

While it may be impossible to prove the veracity of that hoary tradition concerning the existence of a circle of bluestones once erected in the Preselis having been taken to Stonehenge,  we can be a lot more confident that this circle, rim or wheel, had it ever existed, would have been understood by its builders to have represented a temple, and would have  mirrored the zodiac or celestial sphere in some way.

To settle the matter would require that two things can be identified. Firstly, the site of the original (bluestone) circle must be located, a tall order, to put it mildly. Why? Because it would require that archaeologists find a stone circle somewhere in the Preselis where there are probably no longer any stones in situ, else it would have been identified a long time ago. By now it would be presumed to be solely defined by hidden but disturbed earth and in-fill debris where once there had been stones with socket holes. It would be like finding an empty packet of needles in a well-rotted haystack!

If and when located, their second task would be to understand the way that the zodiacal rim or circumference of this structure, the year-circle, was divided up. This cannot be undertaken by conventional archaeologists for they are not trained in, and do not have the required skills in recognising astronomical, geometrical or metrological patterns at prehistoric sites. And then there is the small matter that, for over a century, they have been trained to minimise the significance of prehistoric archaeoastronomy as a matter of course. To mention the father of modern archaeoastronomy, Alexander Thom, is to professionally fall on one’s megalithic rod (btw, that’s two and a half megalithic yards or 6.8 feet). So this second task, to understand the sky-circles, will have to be undertaken by someone who understands both megalithic science, zodiacs and year-circles. Guess who?

The 1970s quest for a Preseli zodiac can now be understood to be more obviously aligned with the present archaeological hunt for the original bluestone circle in Preseli. It is a shiny modern extension to the traditional ‘bluestone myth’, courtesy of Hubert Thomas’s petrological report from 1923, that originally impelled Lewis Edwards and later researchers of earth mysteries to visit the ‘Prescelly landscape’, in search of a landscape zodiac. And this same report almost certainly provided the initial impetus for the current archaeological froth of activity in Preseli.

From this short prologue  a gambling man could reasonably predict that the Preseli bluestone myth may have a few more twists and turns left in the telling by the end of the twenty-first century.


Despite the Preseli zodiac remaining understood having become essentially a dismissed modern myth, it has been possible to demonstrate in only a few paragraphs that this modern myth has roots nourished by much older beliefs, and contains mythical elements that may go way back into the prehistoric period. In effect the myth of the Preseli Zodiac and the tradition of the bluestone circle collide and may be one and the same thing.

So here is the nub of the matter. Ancient traditions are rarely lacking in some core truth, however gaudy, evanescent and flimsy the wrapping paper may appear to suggest otherwise. Open up the package and this particular box is found to contain a tenacious legend about a sky-circle or zodiac or stone circle once built in the Preseli hills. Once the box has been opened up, the quest should then be to locate this hoary monument and try to work out who built it and why, and in so doing reveal its original purpose. It was identifying this task that originally impelled me to write Temple in the Hills, a project led me to the discover the original Stonehenge.


If you want to purchase a copy of Temple of the Hills by Robin Heath, please send an email to, with your name and shipping address, and whether or not you will want the book signed.

This will be acknowledged and the options of payment methods made available.  Currently, these are £10 inclusive of P&P, in the UK, £12 in EU and £15 in US.

Other countries will require an appropriate shipping charge). The book contains over 80 original colour illustrations, including many of the Preseli landscape and its monuments.



The Origins of Stonehenge


Small World Theatre, Cardigan presents

The Origins of Stonehenge: A fully illustrated presentation by Robin Heath

BOOKING-smallworld,      Sunday Nov 6th at 3pm until.. we’re done.        £5.00 per person

What’s all the fuss about?

Prehistoric archaeologists are currently focussing their attention on the Preseli region of West Wales. Why are they here, and what are they looking for?

The answer has to do with Stonehenge, 140 miles away in Wiltshire. Some of this mighty monument was constructed using bluestones that originated here in the Preselis. A fiery debate rages on about how they got there, whether they were taken by human toil or arrived on Salisbury Plain through glacial action.

So archaeologists are now looking for evidence of an original bluestone circle here in the Preseli hills, looking for surviving stones which, if they geologically match those at Stonehenge, will help to prove that human intent moved them there.

Robin claims to have recently discovered the original design for Stonehenge here in the Preselis, and has surveyed it using a theodolite. He will show this design has more to do with the Caer Sidi of Welsh legend, and the motions of sun, moon and stars, than it has with how a few bluestones ever found their way to Salisbury Plain. Today he fully explains why this discovery is an important milestone in the long overdue demolition of the current view concerning the capabilities of our Neolithic ancestors.

In his illustrated and not too technical presentation Robin will also reveal that Stonehenge was a derivative taken from an original design conceived here in Wales, so how good is that?! Even better is that this event coincides with the launch of Robin’s fully illustrated (colour) book on the story behind the discovery, Temple in the Hills, signed by the author, for just £9.99. And it’s getting near to Christmas!

Biography. A graduate of UCNW, Bangor, Robin Heath was previously a research and development engineer with Ferranti, then a college head of technology department, late of Coleg Ceredigion. Since 1990, local author and presenter Robin Heath has been finding the prehistoric science embedded within the surviving megalithic monuments in Britain, Ireland and France. In 1993 Robin founded Megalithic Tours and has written ten books revealing evidence of high culture to be found in the astronomy, geometry and metrology of ancient artifacts. This material has been presented to students at the Prince’s School of Traditional Arts, John Ruskin College, Brasenose College, Oxford, the British School of Dowsing, The Gatekeeper Trust, RILKO (Research into Lost Knowledge Organisation), and the Royal Institute of Mathematics.


Discovering the Original Stonehenge in the Preselis

robin-at-dolmen-llech-y-drybeddPresentation Event at Castell Henllys on 19th October 2016, starting at 7:30pm

Prehistoric archaeologists are currently focussing their attention on the Preseli region of West Wales. Why are they here, and what are they looking for?

The answer has to do with Stonehenge, 140 miles away in Wiltshire. Some of this mighty monument was constructed using bluestones that originated here in the Preselis. A fiery debate is raging about how they got there, whether they were taken by human toil or arrived on Salisbury Plain through glacial action.

So archaeologists are now looking for evidence of an original bluestone circle here in the Preseli hills, looking for surviving stones which, if they geologically match those at Stonehenge, will prove that human intent moved them there.

Robin claims to have recently discovered the original design for Stonehenge here in the Preselis, and has surveyed it using a theodolite. He will show this design has more to do with the Caer Sidi of Welsh legend, and the motions of sun, moon and stars, than it has with how a few bluestones ever found their way to Salisbury Plain.

In his illustrated and not too technical presentation he will also reveal that Stonehenge was a derivative taken from an original design conceived here in Wales, so how good is that?!

A graduate of UCNW, Bangor, Robin Heath was previously a research and development engineer with Ferranti, then a college head of technology department, late of Coleg Ceredigion. Since 1990, local author and presenter Robin Heath has been finding the prehistoric science embedded within the surviving megalithic monuments in Britain, Ireland and France. In 1993 Robin founded Megalithic Tours and has written ten books revealing evidence of high culture to be found in the astronomy, geometry and metrology of ancient artifacts. This material has been presented to students at the Prince’s School of Traditional Arts, John Ruskin College, Brasenose College, Oxford, the British School of Dowsing, The Gatekeeper Trust, RILKO (Research into Lost Knowledge Organisation), and the Royal Institute of Mathematics.

 A launch copy of Robin’s latest book, The Temple in the Hills, will be available at £10.

For more information and to make a booking contact Castell Henllys on 01239 891319

PRESS: Please contact Robin Heath by email (mail AT for interviews or further information,