Some trace of the kings' spirits are present in the barrow, aren't they? When Merry wakes up he says:
'Of course, I remember! The men of Carn Dum came on us at night, and we were worsted. Ah! the spear in my heart!' He clutched at his breast. 'No! No!' he said, opening his eyes. 'What am I saying? I have been dreaming.'Now I have to look up Carn Dum!