Julian Cope presents Head Heritage

As for the Irish Dlomen s? (What exactly is the plural of dolmen??!)
I've always had a problem with the idea that these were covered with mounds. If they were, and I've seen no evidence to prove conclusively that this was so, why did the mounds covering the dolmen vanish when other mounds did not? And if they were covered with mounds, how would anyone know what was underneath? It seems strange to me that if these mounds existed in the first place, why should they have exclusively vanished, whilst all other mounds (i.e. Knowth, Dowth, the English long barrows) have remained in place? Once a mound is in place, it seems to remain so.