The rocks are marked on old maps at NH628437, a short distance from the cairn. There is a well marked close by on the modern OS map, which is conceivably the same mentioned below? Or maybe the water runs straight from the rock?
Above the Inverness District Asylum, and immediately below the ascent to Craig Dunain, is "Fuaran a Chragain Bhric," or the Well of the Spotted Rock. This was in former times a place of great resort, the waters, among other healing virtues, being supposed to be strongly diuretic. The bushes around were adorned with rags and threads; while pebbles, pins, and shells might be observed in the bottom of the spring. We have seen one juniper bush close by so loaded with rags and threads as to be hardly distinguishable. This was also a fairy well, and if a poor mother had a puny, weak child, which she supposed had been left by the fairies in place of her own, by exposing it here at night, and leaving some small offering, as a dish of milk, to propitiate the king of fairyland, the bantling would be carried off, and in the morning she would find her own, and restored in health.
-Alex Fraser, Northern Folklore on Wells and Water, p. 17.
Fuaran a' Chragan Bhreic, or Well of the Spotted Rock,
which forms an apt description, as the spring is situatednear a mass of rock, spotted with various specimens of moss. The water is said to be strongly diuretic, and used to be as much thought of, and resorted to by the inhabitants of Inverness, as now are the wells at Strathpeffer. A juniper bush grows beside the spring, and the mossy hillocks about it afford a seat to the tired pedestrian, whence he obtains a panoramic view of Inverness and the Moray Firth, which well repays the fatigue of the walk and ascent from the town.
The last celebrated spring in Inverness, which remains for us to notice is
Fuaran Ault an Ionnlaid, or Well of the Anointing Burn.
This is situated on the estate of Muirtown, opposite the toll-gate, and immediately below Craig Phadric. Tradition states, that Montrose, while being conveyed a prisoner from Sutherlandshire to Edinburgh, on passing this well, begged of his guards to unloose him from the horse to which he was tied, and allow him to quench his thirst at this well. The request was complied with, and the noble prisoner expressed the great relief and refreshment which it afforded him.
Above Leaken, and between this well and the one previously mentioned, are the remains of a Druidical temple, and it is said the Anointing Well derived its appellation from the circumstance of the Druidical priests resorting to it to bathe and anoint themselves previously to engaging in their solemn religious rites. Like the other springs before specified, this fountain was celebrated for the wonderfully curative effect of its waters, until about 1730, when a soldier's wife is said to have therein washed her child afflicted with scurvy, since which the healing properties of the Annointing Well have forsaken the fluid. [...] The late proprietor, Colonel Duff, had inscribed upon the neat stone-work that protects the spot, the following words:--
Luci Fontisque Nymphis.
Somewhere nearby there was another stone with child-related fairy folklore. Canmore summaries its mention in a journal from 1885:
The hollow stone lies on the summit on the ridge of Leachkin above the Mental Hospital. The stone is flat and hollow in the centre [and] resembles in size and shape a child's coffin. The greater part remains but the foot is broken or weathered away. At one end it used to be hooded over like a cradle and was known variously as Cradle-stone and Clach-na-shia (Fairies' stone).
Alas the OS could not find it in 1962. But I would hope that's not a definitive end to the matter.