Interesting to see that the drawing shows a fourth standing trilithon. If correct it probably shows the stones numbered 59-60 by Flinders Petrie. This is the most northerly trilithon whose stones now lie in pieces & which had fallen by the time John Aubrey planned the site in 1666. It is unlikely to show stones 55-56, the other fallen trilithon at the southeast which forms the centre of the horseshoe as these are believed to have fallen before the Romans arrived. Also interesting to see that the mortice joints are shown.
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