From the Gentleman's Magazine for 1785, pt.1, p360.
Hearing some time ago the above-mentioned appellation given to a ridge of rocks, situated on a mountain, overlooking a deep vale, about half-way betwixt Knaresbrough and Shipton, I was led to suppose the place had once been appropriated to Druidical superstition, in name manifestly implying the "fire circle."
.. On the highest part of one of these rocks is a smooth, regular, well-wrought bason, formed out of the solid stone, 2 feet in depth, and 3 1/2 feet in diameter. On each side of this is a smaller bason formed, each on a prominent point of the rock. A few yards from hence is a rocking stone, the irregularity of the figure making it difficult to ascertain the weight exactly; yet it may be reasonably supposed to weigh near 20 tons, and so equally poised, as to be moved with ease by one hand.
The rocking stone is still marked on the OS map so one can only hope it's still rocking.