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       Megalithic Quadrangles:

There are a handful of megalithic structures in Europe which whilst retaining an essential geometric design - are not circles. Remarkably, they also incorporate a relationship between their dimensions, geometry, astronomy and the latitudes upon which they were built.

As rare as they are, megalithic quadrangles are found at some of the most significant sites in Europe. The Station stones at Stonehenge are probably the most famous, but quadrangles are also found at Carnac, France; and near Evora, Portugal: All of which are areas of megalithic and astronomical significance.

Although Stonehenge is commonly known for its solar orientation, the original construction has been identified as having had a lunar orientation. In addition to this the site was constructed on the exact latitude at which the maximum settings of the sun and moon are at 90� to each other.

The smaller sides of the Station-stone quadrangle are orientated at approximately  51� 10', which is the same as the latitude upon which it sits. The sides of the rectangle were directed towards the maximum lunar and solar settings. The Stonehenge quadrangle also encompasses the second (5:12:13) Pythagorean triangle: Crucuno in France encompasses the dimensions of the first set.


The Bush Barrow Lozenge:

This artefact was discovered near Stonehenge, in the large Bush Barrow, (c. 1,700 - 1,900 BC), which was excavated in 1808 by Sir Richard Colt Hoare and William Cunnington. The barrow contained a male skeleton with rich funerary goods, including a large 'lozenge'-shaped sheet of gold, about 0.5 mm thick. The parallelogram (lozenge) measures 18 cm across and was placed on the dead mans chest.

The redrawn and correctly scaled lozenge, based upon measurements supplied by the Devizes Museum, Wiltshire, England (3)

It has been proposed that it could have served as a solar and lunar calendar, using the sight lines pointing in the direction of Sun solstices and lunar standstills, as the angles on the lozenge are the same as those produced by the sun and moon at their extremes (1)

"By fixing the flat lozenge on a table at eye level and orientating it with its shorter diagonal on the meridian, an observer could use an alidade while watching sunrise or sunset throughout the year. Were the bronze rivets, found nearby, the remains of the alidade? Markings exist on the plaque which indicate that the 16-month calendar was in use. Guide lines exist for inserting the intercalary leap day. Eight additional lines can be identified as indicating moonrise and moonset at the equinoxes' standstills". (2)

(More about Stonehenge)


Crucuno, France:

Crucuno is located at the unique latitude on the Earth at which the solstice sun, both summer and winter, form a perfect Pythagorean triangle relative to the parallel of latitude, that is to the east-west, equinoxial axis of the site. In turn, this 3:4:5 triangle is the first of the Pythagorean triangular set.

The famous Carnac alignments in France have at one end a stone-circle, and at the other a less well known 'cromeleque' which is in-fact a quadrangular enclosure. Prof. A. Thom determined that it was located at the unique latitude on the Earth at which the solstice sun, both summer and winter, form a perfect Pythagorean triangle relative to the parallel of latitude, that is to the east-west, equinoxial axis of the site. In turn, this 3:4:5 triangle is the first of the Pythagorean triangular set.

Prof. A. Thom calculated that the dimensions of Crucuno were 30 x 40 MY. This means that the diagonal measures 50 MY, creating the first of the Pythagorean triangles (3:4:5). The Stonehenge Station-stones encapsulate the second in the set (5:12:13).

Burl (8) said of this geometric feature at Crucuno:

"It has been said that the diagonals of the Crucuno rectangle indicate the rising and setting points of the sun at the summer and winter solstices (Charriere 1965). But such an arrangement for a 3 x 4 (or 30 x 40 MY) rectangle is only possible where certain unusual conditions obtain. We shall proceed to explain these conditions.

First let us find the latitude in which a 3x4 rectangle could be used to show the sun rising and setting at both solstices. For zero true latitude of the suns centre, we have the simple relation sin t = cos A cos λ, where t is the suns declination at the solstice (i.e. the obliquity of the ecliptic), A the azimuth and λ the latitude. Since the Crucuno rectangle is 30 x 40 MY, cos A - 3/5 and so cos λ - (5/8) sin c. If c = 23� 51' (the obliquity of the ecliptic about 1,800 BC), λ - 47� 31'. It is remarkable that this is so near the latitude of Crucuno 47� 37' ".



Quadrangular enclosures at Stonehenge (left), and Crucuno (right).


Xarez, Portugal.

The Xarez cromeleque in Portugal is also a stone 'quadrangle'. Although the original layout of the monument has been questioned, the archaeologist Dr. Pires Gon�alves concluded after several years research on the site that its original design was quadrangular. Perhaps of equal importance is the fact that it belongs to an alignment of sites stretching over 50km, towards the Almendres circle, with an azimuth which closely conforms to the full moon in spring (5).


The Xarez 'cromeleque', Monsaraz, Portugal.

(More about the Xarez-Almendres Alignment)


Both Stonehenge and Almendres (Being two of the oldest and most astronomically significant stone circles in Europe) are located on the latitudes of the extremes of the moons 18.6 year cycle, such that at the latitude of 38.5� (Almendres) the maximum declination the azimuth of moonrise would be 52.5� , while at latitude 52.5�  the extreme moonrise azimuth would be 38.5�, thereby creating a relationship between the two latitudes. This calculation does not take into account factors such as refraction or the variation in horizon elevation or the changes caused by the passing of long periods of time and at its worst is still remarkably only one degree of latitude out.

(More about the Cromeleque da Xarez)


King Arthurs Hall, England.

Although possibly just a coincidence, the cardinally orientated rectangular enclosure called King Arthurs Hall in England is composed of 56 uprights, also suggestive of the lunar count (18.6 x 3 = 55.8)


(Article by A. Whitaker, 2010)


(Stone Circles)




2). Thom, A.S.; "The Bush Barrow Gold Lozenge: Is It a Solar and Lunar Calendar for Stonehenge?" Louisiana Mounds Society Newsletter, no. 37, February 14, 1991.
8). Prof. A. Thom. The Astronomical Significance of the Crucuno Stone Rectangle. 1978. Current Anthropology. Vol 14. No 4.

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