Sir Arthur Conan Doyle: Tales of Terror and Mystery

Tales of Terror 5. The Terror of Blue John Gap (continued)

It is a most lonely spot, and the walks are picturesque in the extreme. The farm consists of grazing land lying at the bottom of an irregular valley. On each side are the fantastic limestone hills, formed of rock so soft that you can break it away with your hands. All this country is hollow. Could you strike it with some gigantic hammer it would boom like a drum, or possibly cave in altogether and expose some huge subterranean sea. A great sea there must surely be, for on all sides the streams run into the mountain itself, never to reappear. There are gaps everywhere amid the rocks, and when you pass through them you find yourself in great caverns, which wind down into the bowels of the earth. I have a small bicycle lamp, and it is a perpetual joy to me to carry it into these weird solitudes, and to see the wonderful silver and black effect when I throw its light upon the stalactites which drape the lofty roofs. Shut off the lamp, and you are in the blackest darkness. Turn it on, and it is a scene from the Arabian Nights.

But there is one of these strange openings in the earth which has a special interest, for it is the handiwork, not of nature, but of man. I had never heard of Blue John when I came to these parts. It is the name given to a peculiar mineral of a beautiful purple shade, which is only found at one or two places in the world. It is so rare that an ordinary vase of Blue John would be valued at a great price. The Romans, with that extraordinary instinct of theirs, discovered that it was to be found in this valley, and sank a horizontal shaft deep into the mountain side. The opening of their mine has been called Blue John Gap, a clean-cut arch in the rock, the mouth all overgrown with bushes. It is a goodly passage which the Roman miners have cut, and it intersects some of the great water-worn caves, so that if you enter Blue John Gap you would do well to mark your steps and to have a good store of candles, or you may never make your way back to the daylight again. I have not yet gone deeply into it, but this very day I stood at the mouth of the arched tunnel, and peering down into the black recesses beyond, I vowed that when my health returned I would devote some holiday to exploring those mysterious depths and finding out for myself how far the Roman had penetrated into the Derbyshire hills.