A small triangular portion, forming the extreme southern part of this
parish, rests on granite, as does also an irregular tract on the
south-eastern boundary; but all the remainder, that is by far the
greater part of the parish, is situated on felspathic rocks, belonging
to the porphyritic series, which are very metalliferous, constituting,
with similar rocks in Camborne and Gwennap (all surrounding the same
central mass of granite) the most important mining district in
Cornwall.
[13] The Cranes (of Crane) are noticed by the Heralds as
residing in Camborn for five descents previously to 1620.
Their arms, Argent, a crane Sable, on a perch raguly Vert.