The Earthwork 'Pi Tord'/Marly-le-Grand FR (Switzerland)

The central point of the earthwork 'Pi Tord'/Marly-le-Grand FR (579.080/179.605) has a very special position because it is on a precise straight line with two mesolithic rock shelters (French: abris), i.e. 'La Souche'/Arconciel FR (575.250/178.950) and 'Flue' (Maggenberg)/Alberswil FR (589.425/181.310), as well as with the church of Ecuvillens FR.
"Very special" because these two rock shelters were found to be only visited during the mesolithic period (and seem to have lost later their significance).
Already in the book Religiöse Geometrie in der Urgeschichte (p.37) it has been proposed that 'Pi Tord' and the position of the church of Ecuvillens could therefore also be mesolithic. Equally possible that 'Pi Tord'(and the position of the Ecuvillens church) have been established towards the end of the mesolithic or at the beginning of the neolithic period.
The earthwork 'Pi Tord' has several fairly impressive ditches (see also www.dillum/html/pitor) which seem to have led to the, most likely wrong, interpretation that a sunken path (French: chemin creux) crossed this earthwork; in reality a sunken path passes at the western end of this earthwork.
Since the rock shelter 'La Souche' is exactly equidistant (3.93 km, always measured horizontally) from 'Pi Tord' and from the huge tumulus 'Moncor' (P.721)/Villars-sur-Glâne FR (referred to the Iron Age), this monument must have had a neolithic or maybe mesolithic predecessor.
'Moncor' is then again equidistant (5.02 km) from the earthwork 'Pi Tord' and from the earthwork 'Räsch'/Düdingen FR (578.490/186.795); 'Pi Tord' is equidistant (7.14 km) from the earthwork 'Räsch' and from the church in Rossens FR, and the earthwork 'Räsch' from this church and from the chapel in Favargny-le-Petit FR (13.05 km).
The straight line  church Rossens  -  chapel Favargny-le-Petit  leads to the large erratic stone 'Es Versannes'/Farvagny-le-Petit (571.315/175.645): it seems strange that this large rock was deposited by the glacier exactly on the hilltop ... One has to conclude that this large stone has been transported by humans to this position (which has also been suggested in other cases).
The church in Rossens is then equidistant (3.09 km) from this erratic stone and from the earthwork 'La Baume'/Corpataux FR (575.065/177.355), and this rock from the earthwork 'La Baume' and from the mesolithic rock shelter 'Barrage de Rossens'(575.175/174.175) (4.10 km). One may assume a neolithic or even mesolithic period for the earthwork 'La Baume' and the positioning of the erratic stone 'Es Versannes'.
The mesolithic rock shelter 'Barrage de Rossens' is then equidistant (6.64 km) from the earthwork 'Pi Tord' and from the former gallo-roman temple in Estavayer-le Gibloux FR (568.515/177.555); the majority of former gallo-roman temples in Switzerland seem to have superposed prehistoric "monuments".
The church in Ecuvillens finds itself probably not by chance on the straight line mentioned in the beginning since it is equidistant (16.40 km) from the rock shelter 'Flue' (Maggenberg) and from the church in Schmitten FR. On the straight line  church Ecuvillens  -  church Schmitten  we find, again in a accurate manner, the two chapels 'Hinter Bruch'/Düdingen and 'Mariahilf'/Düdingen, both leading to other geometric relations not reported here.
The church in Schmitten is equidistant (8.94 km) from the mesolithic rock shelter 'Flue' and from the chapel Montorge/Fribourg (578.940/183.375).
A former chapel in Illens FR (574.585/176.080) is equidistant (2.90 km) from the rock shelter 'La Souche' and from the church in Ecuvillens.
The rock shelter 'La Souche' is finally equidistant (2.54 km) from the ancient chapel on the bridge Ste-Apolline in Posieux FR and from the rock shelter of Illens (574.940/176.400). <This equidistance not indicated for space reasons.> This rock shelter Illens is also equidistant (5.21 km) from the earthwork 'Pi Tord' and from the chapel in Montévraz FR.

All these geometrical relations are only a selection of a larger interlaced network. Many of these alignments may date back to the neolithic or even the mesolithic period.
This study also indicates that geometrical relations may have started very early, as was already suggested in another study (Mesolithic Rock Shelters in the Jura Mountains I).