Arthur Shuttlewood records (in his imaginative 'UFOs Over Warminster' 1979) that "tradition has it that an early Saxon chieftain and his family were interred in the bald patch of earth on the top of the mound in the midst of tree growth" - neatly combining two common story themes - to ascribe prehistoric barrows to Saxons, and the idea that vegetation will not grow on certain graves.
This information is from 'The History of Warminster' by JJ Daniell, the former curate of Warminster, in 1879.
A hillock on the north of the town, formerly bar, now covered with trees, bears the name of COP HEAP. This point commands fine views west, south and eastward, of wood, hill and vale, and many tumuli and military earthworks of high antiquarian and historic interest are visible from its summit. The apex of the knoll is a barrow raised to a considerable height, with a bank and ditch. It was opened in 1809 by Sir Richard Hoare. He found, on the south-west side, at a depth of two feet, a skeleton of a man with the head towards the south, some pieces of worked flint, and fragments of stags' horns, one of which was perforated, as though used for a hammer. On the west side, about three feet down, another skeleton was disinterred, and on the north a kist, or coped grave, was discovered, which had been disturbed in making the plantation; it contained the remains of a woman, with an infant by her side, some ivory beads, and a sea shell.
I liked the seashell.
I was very interested by the curate's next words:
We of the latter day are in no ways justified in wantonly ransacking these houses of the ancient dead. It jars with feelings of decency and religion that graves which have been left undisturbed for 2000 years should be ruthlessly broken into, and the frames of poor mortality shattered and splintered by pickaxe and spade, merely to gratify indelicate and unnatural curiosity. The examination of some FEW barrows would have abundantly satisfied all reasonable claims of archaeological scrutiny, but Sir Richard Hoare and his company, go on without scruple or remorse plundering grave after grave, and revelling, like GHOULS amongst dead men's bones, til scarcely a solitary barrow over the whole area of the county escapes their sacrilegious fingers; notwithstanding that the newly ravaged charnel houses disclose no object of fresh interest, and here and there, as Sir Richard confesses, the skeletons 'grinned horribly a ghastly smile'.