The bridge was thrown across the ravine, and the Evil One stood beyond bowing and beckoning to the old woman to come over and try it. But she was too clever to do that. She had noticed his left leg whilst he was engaged in the construction, and saw that the knee was behind in place of in front, and for a foot he had a hoof.
In her pocket she fumbled, a crust out tumbled; She called her little black cur; The crust over she threw, the dog after it flew, Says she, "The dog is yours, crafty sir!"
Precisely the same story is told of St Cadoc's Causeway, in Brittany. All these stories derive from one source, that it was held necessary to offer a sacrifice when either a house or a bridge or any public building was erected. The usual way was to lay the victim under the foundation stone. I have dealt with this subject already, so that I will but touch on it here. In the ballad of the Cout de Keeldar, in the minstrelsy of the Border, it is said--
And here beside the mountain flood A mossy castle frowned, Since first the Pictish race in blood The haunted pile did found.
In a note Sir Walter Scott alludes to the tradition that the foundation stones of Pictish raths were bathed in human gore.