Megalithic science and some Scottish site plans

‘A cairn supported at its edge by large stones may be removed. … The ring which is left looks like a stone circle.’ (Thom, 1967, 65).Professor A. Thom has surveyed a large number of archaeological sites (Thom, 1967; 1971). These surveys provide the basis from which he deduces the existence of the Megalithic Yard (MY), Megalithic Geometry and Megalithic Astronomy. In considering his evidence for these aspects of ‘megalithic science’ it is pertinent to enquire of each site: Does it date from the Late Neolithic or Early Bronze Age? Is it correctly identified? Do the stones occupy their original positions? Is the site plan accurate? Has the site already been discussed, or since discussed, in the archaeological literature? The example of Unival, discussed in detail later, shows that here Thom has made a serious error in identifying the site, and very probably made surveying errors. These errors vitiate part of his discussion of an important site. This mis-identification, and similar ones, could have been avoided if the archaeological literature had been consulted.