This is the experimental 'barrow' set up by P A Jewell in 1960 - to look at how 'real' barrows would have changed over time. Part of the original study was to actually build the 'barrow' with ancient vs modern methods (using deer antler picks, for example). Archaeologists also wanted to look at weathering, soil movement, ditch silting, etc. They buried cremated human bone, sheep bone, charred and uncharred oak and hazel, wool, cotton, and linen, variously tanned leathers, and flints and potsherds.
(The experimental earthwork on Overton Down, Wiltshire. Ed. P A Jewell. 1960)
In 1960, the British Association constructed an experimental earthwork in the vicinity so that patterns of erosion and the behaviour of buried materials could be studied over a known period. So Hey folks, lets be careful with those picnics.
See Jewell, P.A. (ed) (1963) The Experimental Earthwork on Overton Down, Wilts. London: British Association for the Advancement of Science.