Typically, rocking stones are residual corestones formed initially by spheroidal weathering and have later been exposed by erosion or glacial erratics left by retreating glaciers.
Davies Gilbert suggested that the word "logan" comes from a Cornish expression for the movement that someone makes when inebriated: Such stones are common in Britain and other places around the world.
[3][4] Pliny the Elder (23–79) wrote about a rock near Harpasa (in Caria, Asia Minor) "that can be moved with one finger, but that also resists a push made with the whole body.
"[6] There are stones in Iona called na clachan-bràth, within the precincts of a burial ground, and placed on the pedestal of a cross, and have been according to Pennant, the supports of a tomb.
[citation needed] A rocking stone is recorded near the site of Saint Bride's Chapel.
The Logan Stone is a grey granite rock and rests on greywacke, and can easily be moved with one hand.
Local legend states that an old sorceress cursed two pirate ships that were menacing the village, turning them to stone.
The Kyaiktiyo Pagoda in Burma is a religious shrine built on top of a huge granite boulder that is also a rocking stone.
[12] A stone used to rock on a gritstone outcrop on Warley Moor near Halifax in West Yorkshire.
[13] Ayrshire in Southwest Scotland apparently is endowed with a geology that lends itself towards the formation of rocking stones.
A rocking stone that some associate with the Druids is on Cuff Hill in Hessilhead, near Beith in North Ayrshire.
The Witch's Stone or Boarstone on the Craigs o'Kyle is recorded by the author John Smith as having rocked.
The Clochoderick Stone near Howwood and Kilbarchan in Renfrewshire used to rock, and it is said that the Druids used it to judge people.
It is also said to be the burial place of Rhydderch Hael, King of Strathclyde, who was the victor at the Battle of Arderydd near Arthuret in the Borders.
[17] A 150-ton glacial erratic occurs on Rockingstone Avenue in Larchmont, New York, that was so perfectly balanced that just a small touch would allow it to rock back and forth.
A very sensitive rocking stone called Men Amber (sometimes written as Men-Amber or Menamber) was on a high ridge in the parish of Sithney, near Pendennis, Cornwall.
One rumoured motivation for the dislodging was a purported prophecy of Merlin, who supposedly said that Men Amber would stand until England had no king.
For example, Modred, in William Mason's dramatic poem "Caractacus" addressing the characters Vellinus and Elidurus, says of the Logan Rock: Thither, youths, Turn your astonish'd eyes; behold yon huge And unhewn sphere of living adamant, Which, poised by magic, rests its central weight On yonder pointed rock: firm as it seems, Such is the strange and virtuous property, It moves obsequious to the gentlest touch Of him whose breast is pure; but to a traitor, Tho' ev’n a giant’s prowess nerv’d his arm, It stands as fixt as Snowdon.
Goldsmith was apparently motivated to disprove the claim of Dr. Borlase, who wrote in Antiquities of Cornwall in 1754 that: In the parish of S. Levan, there is a promontory called Castle Treryn.
On the western side of the middle group near the top, lies a very large stone, so evenly, poised that any hand may move it to and fro; but the extremities of its base are at such a distance from each other, and so well secured by their nearness to the stone which it stretches itself upon, that it is morally impossible that any lever, or indeed force, however applied in a mechanical way, can remove it from its present situation.Goldsmith was determined to demonstrate that nothing was impossible when the courage and skill of British seamen were engaged.
They demanded that the British Admiralty strip Lieutenant Goldsmith of his Royal Navy commission unless he restored the boulder to its previous position at his own expense.
However, Mr. Davies Gilbert persuaded the Lords of the Admiralty to lend Lieutenant Goldsmith the required apparatus for replacing the Logan Rock.