By far the greater part of this parish is composed of serpentine, which is generally of the red variety, with dark-coloured and shining scales of diallage.
South of a line drawn east and west, a little north of the church, across the peninsula of the Lizard, the rocks are for the most part schistose, and are covered with a deep soil, which is exceedingly productive.
The cliffs around this part of the parish are very interesting, and if minutely scrutinized would probably throw some additional light on the nature and position of the
serpentine. To this end it would be necessary to make the survey from the sea, which could only be effected occasionally, and under very favourable circumstances.
At Perranbonse Cove, near the church, the slate is a variety of schistose diallage rock, such as has been already described at Cadgwith.
Near the lighthouses the cliff is formed of a glossy decomposing talcose slate, which has been called by some geologists Micaceous schist, but talc appears to be the characteristic mineral, as it is present in a distinct form throughout the veins, with nodules of quartz abounding in this slate.
At Hensall Cove the blue slate is much intermixed with calcareous spar in various forms, resembling the slate adjoining the calc shists, and blue limestones at Veryan, Padstow, and some other parts of Cornwall.
The Editor would take the liberty of adding that in this parish veins of steatite run through the serpentine formation; and that considerable quantities have been raised by the late Mr. Wedgwood from some veins larger than the others, and near the cliff. The soft and unctuous qualities of this substance gave it the popular name of soap rock. Thin veins of native copper traverse also the serpentine formation; but never in sufficient quantities to bear the expense of mining. In some places specimens of semitransparent serpentine are found shot through by branches of native copper, forming what has been termed dendrites.
At Kynans Cove the assemblage of rocks possesses such an extraordinary degree of beauty and magnificence as to render it one of the spots most worthy of attention on the whole coast. The interest excited by the general effect is heightened, on a more close inspection, by natural caverns, and the intervals between the rocks are perpetually varied in their appearance by the swell and by the subsidence of waves from the sea.