I have written before about the mound in the middle of Stonehenge - between Stones 53 and 10 - which David Field has some thoughts about.
In the excitement of finding other parchmarks this summer I also spotted something strange on the mound.
My updated version of Cleals map http://www.sarsen.org/2013/09/cleal-et-al-twentieth-century.html shows where the known excavations in the mound area are and I have outlined the squares in the bottom picture, the two smaller Atkinson ones and the corner of the more recent Darvill and Wainwright's one.
In the area between them there appeared a circular parchmark with a lush centre.
(A large hole left into chalk can produce this as the chalk edges collapse to give a dry rubble edge and the centre depression is filled with blown soil).
It is off the bluestone circle and I don't think it is an artifact produced by the watering, could it be a hint of a large stonehole?
click to embiggen
It is also visible in this picture taken this year if you look closely: