This is from Highways & Byways in The Border,
The Fairy Folk have fled from scenes tainted by an atmosphere of railway and modern vila. Even the Water-bull has ceased to shake the hills with his roar around Sir Walter [Scott’s] “small but deep lake” at Cauldshiels. yet as late as the time of our grandsires people told gravely ow, one warm summer’s day, a lady and her groom, riding by the sullen shore of this “lochan”, ventured a little way from the edge in order to water their thirsty horses and were immediately engulfed in the Kelpie’s insatiable maw.
If such a tragedy ever did happen no doubt the explanation is simple enough. Without any warning the hard upper crust would give way beneath the horses’ feet, and, struggling vainly, they would sit in the fathomless, spewing, inky slime below. Once trapped in that, no power on earth could ever bring them out again, dead or alive.
A like fate befell the writer when fishing alone one day in a gloomy, forsaken, kelpie-haunted Border hill loch. Dense fog came down, wreathing over the quiet water, hiding the dripping heather and the bent hill. A bird of the bittern kind boomed dismal at intervals, and a snipe bleated. It was a cheerless prospect; and the temperature had fallen with the coming of the fog. But through the mist could be heard the song of trout rising in the little loch, and one bigger than his fellows persisted in rising far out. The sound was too tempting. The fisher weed out, and still out; and her the big trout rose, luring him on. Another step and another; it was no longer stony underfoot, and the bottom began to quake. Still the voting was hard enough and nothing happened; and again the big fish rose just out of casting distance. One more step would do it; and what danger could possibly be added in so small a distance? So one more step was taken, and – without a second’s warning the crust broke. Only one thing saved the fisher; instinctively, as he sank through the fetid slime, he threw himself on his back, striking vigorously with his arms. But it took many an agonised, almost despairing stroke ere his legs sucked out of the death trap. Nor as long as there was after shoreward deep enough o swim n, did he again attempt to wade. His rod had not been abandoned, which was matter for gratulation; but, soaked to the skin, chilled to the very marrow and reeking with the stench of putrid swamp, it was no thing of joy that day to make his devious way home over an unfamiliar hill that was wrapped in impenetrable folds of dense mist.
I am also intrigued by the name ‘kelpie’, as it is also the name of an Australian cattle dog, a cross between dingo and collie I think. Maybe they’re quiet and illusive too.