Mysterious Britain quotes Hogg's account. A farmer in Bowerhope got a breed of the water cow, which he kept for many years while they multiplied greatly, and he never had cattle thrive so well. Then, following some outrage or disrespect on his part towards them, the old dam came out of the lake on a pleasant March evening and gave such a roar that all the surrounding hills shook. Her progeny, nineteen in number, followed her quietly into the loch and were never seen again.
The story was repeated by James Mackinlay in his Folklore of Scottish Lochs and Springs (1893). Local tradition also says the loch is bottomless. A statue of Hogg stands near the loch close to Tibbie Shiels Inn. This is a folk tale of a water spirit and not a sighting, and the only source I have is a modern summary of Hogg.
Comments