Cairn

Part of speech: noun (n.)

1. A rounded or conical heap of stones erected by early inhabitants of the British Isles, apparently as a sepulchral monument. Now here let us place the gray stone of her cairn. Campbell.

2. A pile of stones heaped up as a landmark, or to arrest attention, as in surveying, or in leaving traces of an exploring party, etc. C. Kingsley. Kane.