Where the Coldfells blended into the Misty Mountains and the Giant Trace ran up from Dunland just below the tree line, a traveller wandering the vales and possessing a good eye could see three strange piles of stones (S."Gonnaedh";Hi."Ilcairn"), each on a separate mountain ridge, placed about ten miles apart. Each pile wass the size of a prosperous farmhouse, stacked in an open and obviously artificial way. The stones, hewn from local granite, were typically about the height of a small man and cut to differing cross sections with buttresses jutting off at odd angles. The length, shape, and positioning of the stones varied so as to form a complex and eerie pattern. It was so bizarre, in fact, that anyone looking at the assemblage with the intent of deciphering the pattern grew dazed and ill. The Stone Giants of the Misty Mountains came to worship the forces of creation at the Stone-piles, as did the Trolls of the Coldfells and Trollshaws. Dwarves attempting to exterminate the Trolls of Rhudaur had scattered the Stone-piles several times during the Second Age. Each time, the Giants rebuilt the strange conglomerations, and the Dwarven leaders died mysterious and unpleasant deaths. The Arnorians who came later heeded the Dwarves' warnings and never interfered with these shrines.
The Stone-piles were, in fact, the key to the fecundity of the Trolls of the Trollshaws. They could only be destroyed during times when Sauron was inactive . If someone had deduced the connection in the first millenium of the Third Age, much local history would have been different. As it was, the piles emitted periodic bursts of energy that tripled or bettered the fertility rate of any Trolls in their immediate area. The less they were worshipped, the more frequent the energy outbursted. The Trolls of Rhudaur, therefore, were always subject to sudden unexplained surges in number, and exterminating them was next to impossible.