Doctor Paris has remarked on the granite of this district, that it
contains full twenty-five per cent. of felspar, which he says at once
explains the rapidity of this stone’s decomposition, and the fertility
which is so very unusual in granitic countries; and that this granite
in a state of decomposition, when it is provincially called growan,
has actually been applied to some lands as a manure, and with the best
effect.
I had the pleasure of attending Doctor Withering (author of the
Arrangement of British Plants, &c.) to the Land’s End in 1793, when he
expressed much surprise at the fertility of a granitic soil, and
explained it as Doctor Paris has since done, by observing that in all
the granite he had previously seen siliceous matter abounded, and that
the very word was synonymous with sterile, but that here felspar and
fertility appeared together.
Felspar is said to contain nearly a third part of its weight of
alumine, about an eighth part of lime, and a twentieth of soda.
[22] That there exists, however, a prevalent connection of
these monuments with allusions to dancing, is shown in the
Essay on Dracontia, by the Rev. J. B. Deane, F.S.A. in
Archæologia, vol. xxv. The name of Dans Maen is generally
given to the various stone circles in the county of
Cornwall. Dr. Borlase remarks that there are four circles in
the hundred of Penrith, having nineteen stones each; viz.
Boscawen-ûn, Rosmodrevy, Tregaseal, and Boskednan, the two
most distant being not eight miles apart. Of Boscawen-ûn
there are views in the works of Borlase and Stukeley, as
well as among the more accurate etchings by William Cotton,
Esq. 4to. 1827. He has also given a view and plan of the
dans-meyne at Bolleit in this parish; and two obeliscal
stones at the same place are represented in Borlase, pl. 10.
See also in pl. 14 the hanging stone in Karn Boscawen, and a
Maen Tôl, or holed stone, both in Burian; as is the circle
called Rosmodrevy.――EDIT.
[23] Engraved in Gough’s Camden, vol. I. pl. 1.