There may be some residual mythical references in this song. According to Walker’s Woman’s Encyclopedia of Myth, Flidhais was a Celtic woodland goddess who took the form of a doe, nurtured heroes on quests, and brought them to fairyland when they died. Also it’s interesting to note that the Celtic goddess Brigid had a sacred grove where one could enter the Underworld (earthen lake?) at Derry Down. And the chorus of the song apparently refers to this site:   “With a down Derry Derry Derry down down”. Ravens are also associated with themes of death and resurrection and the underworld.