A lot of the Dutch dolmens stand together as a set of two or three. Beside this, they do not differ much - not in length, number of stones, orientation or port. But the duo's tend to be a little longer then the trio's. With duo's 11 of the 16 dolmens have 6 pairs of side stones or more, while the sets of three have 5 or less. Because of the higher number of side stones it's nasty to track down orientation patterns in duo's and there is more chance on exidental patterns. Therefore they fall outside the focus of this website. In the tables below the orientations of the duo's and trio's are shown together with their difference. With the sets of two their mutual orientation is mentioned too. Depending on how one would measure, the values can differ 60° easily. Because of this no values are given but a general description. The mutual orientation of the trio's is the subject of this page. The abbreviation GG&CF stands for Gonzalez-Garci and Costa-Ferrer (see the page Former research).
|Dutch dolmens||van Giffen||GG&CF||Difference||Mutual|
|D3 and D4||94° and 89°||99° and 90°||7°||extend|
|D17 and D18||83° and 106°||87° and 108°||22°||transverse|
|D19 and D20||117° and 96°||119° and 96°||22°||extend|
|D21 and D22||46° and 74°||39° and 67°||29°||extend|
|D28 and D29||100° and 73°||99° and 71°||28°||transverse|
|D36 and D37||103° and 100°||105° and 99°||5°||extend|
|D50 and D51||88° and 74°||88° and 73°||15°||transverse|
|D53 and D54||73° and 110°||74° and 112°||38°||???|
|Dutch dolmens||van Giffen||GG&CF||of satelites||with central|
|D23, D24 and D25||77°, 68° and 91°||unreliable||9°||14° and 23°|
|D38, D39 and D40||44°, 25° and 167°||44°, 25° and 164°||19°||122° and 141°|
To make a systematic comparison of the trio's possible, with each dolmen the cellar edge of the Z'-row with S2 (numbering after van Giffen) was appointed as measuring spot. In the long barrow both small dolmens were involved seperately for measurement. The eastern most dolmen appears to be part of the systematics. In each group one central dolmen can be appointed with two satelites. Those satelites lay in corresponding direction with their azimuth at 115°-120° and 138°-143°.
Gff = numbering according to van Giffen. Spr = numbering according to Sprockhoff.
The dolmens near Emmen and Bronneger have been researched for an supporting structure in according with the orientations. Those near Benstrup are too tumbled down for a closer study. The relative longer distance between dolmens makes it possible to determine orientation lines to less then a degree. From each dolmen cords have been stretched along the sightlines with at the end a sight post. In that way an orientation line between two marks can be measured at longer distances with less then 10 cm deviation. A shift of 10 cm at a distance of 25 metre results in an anomaly of 0.2°.
D40: Setting up orientation lines with ropes.
Flat sides of stones Z1 and Z2 in D25.
The first hint for a supporting structure was found with the side stones Z1 and Z2 of the central dolmens D25 and D40. They stand with a flatted side along the orientation lines. Per orientation line more then one marking and/or (half) diagonals play a role in the fixation. In the figure below the markings are drawn in blue. The positions of the satelites in relation to the central dolmen are in Bronneger as well as in Emmen 117° and 140°.
Afterwards D8 appeared to have the signs of a central dolmen too. Also in this dolmen the side stones Z1 and Z2 stand at an orientation of 117° and does the orientation of 140° run between the side stones at 140°. Once two other dolmens stood in the close surrounding of D8. One of them finds itself at an mutual orientation of 140° and could have been a satelite, but the other doesn't to have had the right direction. Furthermore the flat sides in D8 point in the other direction, so we should look for the satelite in that direction.