Milston 12 (D) round barrow at SU 19294671. Mound 135' x 6', bank 21 x 2', ditch 18' x 1 1/2'. A large circular mound encircled by a vallum outside of which is the surrounding ditch. Opened by Colt Hoare who doubted whether it was sepulchral; no signs of any interment, and the only finds were `a few animal bones of deer etc.' (1)
Milston 12. As described by Grinsell it is `a round barrow of exceptional type' (1). Presumably a barrow, it consists of a central flat-topped mound surrounded by a berm above the outside groud level, a bank and an external ditch. Total diameter about 70m. Resurveyed at 1:2500. (2)
Originally recorded as Milston 12 by Goddard. (3)
This barrow is visible as an earthwork on aerial photographs and has been mapped by both RCHME's Salisbury Plain Training Area NMP and EH's Stonehenge WHS Mapping Project. (4-5)
I've not visited this site, or even seen any photos of it, but Michael Dames refers to it in his book The Silbury Treasure writing in the chapter Neolithic Harvest Hills in England:
Surviving members of the same class [as Hatfield Barrow] may include the enormous structure on Silk Hill, Wiltshire - a large circular mound 135 feet in diameter, 18 feet high, and encircled by a ditch. This edifice was opened by Hoare, who doubted whether it was sepulchral. There was no sign of internment, and the only finds were 'animal bones of deer etc.'
If Dames is right, the Silk Hill Mound is essentially a scaled down (and simplified) version of Silbury Hill.