A Logan Stone.
Some of the more famous logan stones are the Hanging Stone on Hangingstone Hill, The Rugglestone at Widecombe-in-the- Moor, The Nutcrackers on Sharpitor in Lustleigh Cleave (which is marked on the OS map as being a logan stone), the Nutcracker Rock on Rippon tor which again is marked as a logan stone on the map, albeit wrongly called the ‘Nut Crackers’, Black tor logan, Whooping Rock on Easdon Tor and one on Shilstone tor. There are also numerous other smaller logans on many of the other tors and you can have hours of childish fun rocking back and forth on them. It is slightly disconcerting when without realising it you stand on one and suddenly find your balancing skills put to the test.
Many writers have suggested that the logan stones were used by the Druids in their various rites and rituals. Imagine how awesome it could have been to see a venerated priest moving several tons of granite with his finger if you did not know he was rocking a logan stone. It is hardly likely that the prehistoric people knew how the rock was formed and so it would have been regarded as some magical power to be able to move these huge granite boulders.
Sadly over the years many of the larger logans have lost their ability to rock, this in a couple of cases has be due to acts of vandalism. There was a great debate a few decades ago when the Nutcrackers on Sharpitor was vandalised and then after several attempts restored by the army. The controversy was whether they replaced the original rock, either way it did not ‘logg’ anymore. The Hanging Stone on Hangingstone Hill was also restored by the army in 1966 when it was reported that they had found the centre of gravity and the stone rocked once more. It obviously has moved since because it no longer rocks and rolls: