Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/79

Rh moveable in Cornwall. I made an attempt to ascertain its weight by measurement. It may without much inaccuracy be resolved into two frusta of pyramids, on a common trapezoidal base, their union forming an irregular four-sided prismatic figure, 17 feet in length, and 32 feet in circumference about the middle part. Comparing the solid content of the stone, as deduced from this approximated measurement, with the sp. gr. of the granite of which it is composed, the weight appears to be 65,8 tons, a deduction if not precise, sufficiently accurate at least to satisfy general curiosity.

It would be superfluous to combat the opinion of those, who like the of Cromwell's time, in the instance of the rocking stone of Merramber, fancied these stones to be the productions of art directed to religious purposes. The accidental coincidences which give rise to their formation, will be considered when I have reviewed the other tors which are the subject of this paper.

The Cheese-wring, (Pl. IV.) of which the second drawing is a representation, occupies the highest ridge of a hill to the north of Liskeard, one of that collection of hills which decline from Rough-tor, and Brown-willy, and which form the most elevated part of Cornwall. The summits of all these hills are covered with granite cairns in different states of ruin and disintegration, and their sides are strewed to great distances with the bowlders which have fallen from them at different times.

The migration of stones is here readily to be traced upon a scale easily comprehended. The granite of which these hills are composed is well known, and has been often described.

It is not far from the Cheese-wring that the first traces are found of the asbestos and steatites which are known to be so abundant and conspicuous in the parish of St. Cleer.

The inspection of the drawing will show that this remarkable cairn