The presence of erratic boulders was accounted for by popular legend in a variety of ways. Sometimes it was declared that the Virgin or a saint, while bearing an enormous stone through the air to be used in the construction of a church, had learned on the way that the church was completed and the stone no longer needed, and immediately let it drop to the earth.[60] A stone having the rude form of a chair or seat, and known as Canna’s Stone, enjoyed repute in Wales for its curative powers. It was in a field in close proximity to the church of Llangan, Carmarthenshire, which owed its foundation to St. Canna. Near this stone is a well called Flynon Canna, the waters of which were believed to be a cure for ague. To make the cure effective, however, the patient, after imbibing the sacred water, had to sit for a time in Canna’s Stone, and if he dozed while sitting there this was considered to promise a speedy recovery. The combined treatment by well and stone was often repeated for several successive days and was occasionally prolonged for two or three weeks.[61] That a child could be cured of disease by being passed through an aperture in one of the sacred stones that had formed part of a dolmen is shown in the case of a stone of this kind preserved in the church of Villers-Saint-Sépulcre, dept. Oise, France. There is another such stone in the same department, at Trie, used in a like way for the cure of feeble children or those suffering from rachitis. This reveals in a striking way the persistence of superstitious beliefs which were already condemned in 567 A.D. by the council of Tours, which prescribed that the eucharist should be refused to those who venerated these so-called sacred stones, and at a still earlier date, in 443 A.D., a council decree pronounced those bishops guilty of sacrilege who permitted the making of vows over these stones or the deposition of offerings thereon.[62] Some of the stones of the druidic dolmens were called by the French peasants of a later age _pierres tourniresses_, or “whirling stones,” for it was solemnly asseverated that at midnight on Christmas Eve these stones gyrated on their base. A still stranger fancy was that some other stones of this class became fearfully thirsty at times, once every hundred days, or perhaps only once in a century, and then rolled off to the nearest stream to slake their thirst. Under others, again, it was believed that a hidden treasure reposed, watchfully guarded by a terrible dragon. However, on one night in the year, while the clock was striking twelve, he snatched a moment’s sleep, and whoever was clever enough and quick enough to make use of this chance could acquire untold riches.[63]