excavation at the circle in the 1980s, Lambrick concluded that when it had been originally erected, it would have been a "more perfect circle" than it is today. He thought that each of the stones would have touched one another, creating a continuous barrier all the way around. He also speculated that the monument's builders intentionally placed the smoother sides of the boulders to face inwards. The outer facing sides are predominantly rougher in texture. Resistivity and magnetometry surveys undertaken during the 1980s revealed four magnetic anomalies within the centre of the circle, possibly representing "pits related in some way to local ground surface undulations and the presence of localised burning." Lambrick noted that similar features could be found within the stone circles of Mayburgh, Stenness and Balbirnie. He said that it was a possible original prehistoric feature, although accepted it may equally have been the result of refuse deposited in the Romano-British period, or tree-planting holes. Meanwhile, archaeological excavation revealed that there was "no indication" of there having been "a substantial ditch" either inside or outside the bank on which the stones were positioned. Making an estimate of the time and manpower required for this project, Lambrick concluded that each of the King's Men could have been constructed by a team of ten or twenty (depending on the size of the stone) in about two-and-a-half hours. He noted, however, that the time could have been reduced if the workers had been divided into two groups for some of the smaller stones. Concluding his examination of this issue, he argued that "83 journeys by the whole team would have been required, giving an actual construction time of c 137 hours, or 3735 manhours." Adding to this "210 manhours" for digging the post holes for the boulders, as well as "40 manhours for cutting timber and making the shear-legs and sledges", and "another 40 for fetching and trimming the timbers", Lambrick concluded that a total of around "4035 manhours" would have gone into the construction of the stone circle. This would have been about three weeks' work for around twenty workers. Since the late 19th century, the monument has been in part a reconstruction. In 1882, the owner of the site re-erected around a third of the stones that had previously fallen. Some were moved from their original positions. Using documentary evidence and lichen growth analysis, archaeologists have established that around