rocking stone

(redirected from Clach brath)
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rocking stone

[′räk·iŋ ‚stōn]
(geology)
A stone or boulder, often of great size, so finely poised upon its foundation (as on the side of a hill or cliff) that it can be moved slightly backward and forward with little force (as with the hand) and still retain its original position. Also known as roggan.