The County Durham Sites & Monuments Register describes the Bracken Heads site as:
"a group of seven carved rocks and a cairnfield on the top of a ridge at Bracken Heads. The cairnfield consists of at least 14 cairns. The largest is c. 16m in diameter and 0.4m high. It has been substantially damaged by stone robbing. The remainder of the cairns are between 10m and 3m in diameter, and up to 0.6m high. Most are undisturbed, but the centres of a few closest to the wall are dished because of the removal of stone for walling. The carved rocks are closely associated with the cairnfield, and occur both sides of the wall between Folly Top and Barnard Castle Allotment... The carvings on all the rocks consist of cup-marks; these are joined in pairs by short grooves on two of the rocks. The rocks are mostly or completely covered by turf, and their positions are marked by loose stones which have been placed on top of them. The carvings are unusually fresh, presumably because they have been covered for much of the last 4000 years."
The SMR lists it sources as:
Beckensall S & Laurie T, Prehistoric Rock Art of County Durham, Swaledale and Wensley, 1998, p. 86.
Brown P, Carved rocks and cairns at Bracken Heads, 2003; & Carved rocks in Stobgreen Plantation, 2003.
Gledhill T, SM 35956 Cup-marked rocks and cairnfield at Bracken Heads, MPP Files, 2003; & SM 35957 Cup-and ring-marked rock in Stobgreen Plantation, MPP Files, 2003.
The map reference given here is taken from the online SMR, where references are only accurate to within 1km. The SMR does have its location listed inaccurately (it begins its reference with the letters NY, which should be NZ) - I have corrected this.