diminishes the astronomical significance of the number of the Aubrey Holes and their circular arrangement and tends to suggest that any astronomical purpose for the site may have been no more than symbolic. According to the astrologers Bruno and Louise Huber the Aubrey holes were an astronomical abacus to mark the positions and calculate the movement of lunar nodes. Extra-astronomical interpretations Mike Pitts has asserted that the Aubrey Holes did in fact originally hold timbers and compares the site at this stage to Woodhenge, The Sanctuary near Avebury and other Neolithic timber circles. Such a view contradicts the archaeo-astronomical view of the holes as being a unique predictive device. In fact, early Stonehenge may have been barely different from the other Neolithic timber circles of the British Isles, which had varying numbers of postholes and orientations and could therefore not have been used for in island-wide eclipse predicting. The interpretation of such timber circles is unclear, although parallels were drawn with Native American totem poles by Stuart Piggott in a 1946 BBC radio lecture. A 50 cm high carved wooden figure found in the Thames Marshes in 1912 and carbon dated to 2460–1980 BC has been used rather tenuously to support the theory of carved wooden posts serving a more terrestrial purpose. Another possible explanation for the holes, suggested by Richard Atkinson, is that they were excavated in turn in some unknown ritual involving a procession around the inside of the monument. Others have pointed out the significance of the 28-day human menstrual cycle and argued that the holes may have been fertility indicators. Alexander Thom calculated that the circle of holes had been laid out in a circumference of 131 of his megalithic rods although this number has no known significance. A recent CAD study of the holes has shown that a 56-sided polygon can be generated by the simple use of square and circle geometry. Aubrey Burl also notes that the azimuth of the Heel Stone, beyond the Aubrey Circle, marks the midpoint in the swing of the Moon between major and minor standstill points, at 51.3 degrees. The true purpose of the holes may never be known, although future excavation of the remaining twenty-four using modern archaeological techniques will certainly provide more information. References Bibliography Stonehenge Chalk pits