The Canmore site record calls this 'The Witch's Stone'.
On the top of the Craigs of Kyle there was, in former times, a chapel dedicated to Saint Bride. The only vestige of it now remaining is the well, which is still called Saint Bride's Well. No notice is taken of this ancient place of worship in Chalmer's Caledonia, or the Statistical Account of Scotland: but it is worthy of remark, from the existence of another remain of antiquity which has hitherto escaped the observation of topographical or antiquarian writers. This is a Rocking-Stone -- adding another to the many proofs, that the early propogators of Christianity invariably planted the Cross where the inhabitants had been in the habit of assembling under the Druidical form of worship.
The Rocking-Stone occupies the summit of the highest of the Craigs. It is an exceedingly large elongated block of granite, but must have been at one time much larger, as several pieces seem to have fallen from it through the action of the weather, being much exposed to the moisture and storms of the west.
We regret our inability to take an accurate measurement of the stone at the time of our visit, not having been aware of the existence of such a relic. Tradition is silen in reference to it, though it is pointed out as a curiosity by the people in the vicinity. There can be no doubt, however, of its Druidical character. Although it has now lost its vibrating power, being propped up by stones, the pivot is easily discernible.