Before proceeding to the metalliferous district of Saint Just, we may observe that, if the traveller's object be to reach Saint Ives by the road along the cliffs, through the parish of Zennor, he will meet with a most cheerless country, but by no means destitute of geological interest. He ought particularly to examine a bold rocky promontory, called the "Gurnard's Head," where he will find a succession of beds of slaty felspar, hornblende rock, and greenstone. The geology of this headland has been accurately described by Dr. Forbes in the second volume of the Transactions of the Royal Geological Society of Cornwall. Polmear Cove ought also to be visited on account of the Granite veins, which are perhaps as singular and interesting as any of those already described.—But let us proceed to complete our examination of the coast of Saint Just. Many of the mines are situated on the very edge of the cliff, and are wrought to a considerable distance under the sea; but all communication to them is from land.[56] For a description of the numerous minerals found in this district,[57] we must refer the reader to the highly valuable paper by Joseph Carne, Esq. which is published in the second volume of the Transactions of the Royal Geological Society of Cornwall. We cannot, however, allow the mineralogist to pass Trewellard, without reminding him that, at this spot, Axinite was first discovered in Cornwall, and that the most beautifully crystallized specimens of that mineral, scarcely inferior to those brought from Dauphiné, may still be procured here. In the cliff at Huel Cock Carn, a vein of this mineral, of a violet colour, three feet in width, may be traced for upwards of twenty yards; and in its vicinity there is to be found also a vein of garnet rock. Apatite, of a greyish-white colour, associated with Hornblende, may be seen in the same spot. In the slate rocks between Huel Cock and Botallack, Prehnite has lately been found, for the first time; it appears to form a small vein, which in one part is divided into two branches. Upon the discovery of the above mineral, says Mr. Joseph Carne, an expectation was naturally formed, that Zeolite, its frequent associate, and an equal stranger to Cornwall, might shortly make its appearance. This opinion has been lately verified by the discovery of, at least, two varieties of that mineral, imbedded in the Prehnite vein, viz. Stilbite, or foliated Zeolite, crystallized in flat four-sided prisms, with quadrangular summits; and the radiated Mesotype, which sometimes contains nodules of Prehnite. Other specimens have been found in rather an earthy state, and may possibly be the mealy Zeolite of Jameson. In the same slate rocks Apatite occurs of a yellowish-green colour, and crystallized in hexaedral prisms. In the granite rocks on the high hills south-east of Trewellard, Pinite is to be observed.
We arrive at the "Crown Engine" of Botallack—
"How fearful
And dizzy 'tis to cast one's eyes so low,
The crows and choughs, that wing the midway air
Show scarce so gross as beetles:——
——I'll look no more,
Lest my brain turn, and the deficient sight
Topple down headlong."
This is undoubtedly one of the most extraordinary and surprising places in the mining districts of Cornwall, whether considered for the rare and rich assemblage of its minerals, or for the wild and stupendous character of its rock scenery. Surely, if ever a spot seemed to bid defiance to the successful efforts of the miner, it was the site of the Crown Engine[58] at Botallack, where at the very commencement of his subterranean labours, he was required to lower a steam engine down a precipice of more than two hundred feet, with the view of extending his operations under the bed of the Atlantic ocean!!! There is something in the very idea which alarms the imagination; and the situation and appearance of the gigantic machine, together with the harsh jarring of its bolts, re-echoed from the surrounding rocks, are well calculated to excite our astonishment.
But if you are thus struck and surprised at the scene when viewed from the cliff above, how much greater will be your wonder if you descend to the surface of the mine. You will then behold a combination of the powers of art with the wild sublimity of Nature which is quite unparalleled; the effects of the whole being not a little heightened by the hollow roar of the raging billows which are perpetually lashing the cliff beneath. In looking up you will observe troops of mules laden with sacks of coals, for the supply of the engine, with their undaunted riders, fearlessly trotting down the winding path which you trembled at descending even on foot. As you approach the engine, the cliff becomes almost perpendicular, and the ore raised from the mine is therefore drawn up over an inclined plane,[59] by means of a horse engine placed on the extreme verge of the overhanging rocks above, and which seems to the spectator below as if suspended in "mid air."
The workings of this mine extend at least seventy fathoms in length under the bed of the sea; and in these caverns of darkness are many human beings, for a small pittance, and even that of a precarious amount, constantly digging for ore, regardless of the horrors which surround them, and of the roar of the Atlantic ocean, whose boisterous waves are incessantly rolling over their heads. We should feel pity for the wretch who, as an atonement for his crimes, should be compelled to undergo the task which the Cornish miner voluntarily undertakes, and as cheerfully performs; yet such is the force of habit, that very rarely does any other employment tempt him to forsake his own; the perils of his occupation are scarcely noticed, or if noticed, are soon forgotten.