Having heard from my esteemed friend and colleague, Mr. J. W. Wetherell, that some years ago a brown crystalline substance had been found in a cave close to the sea, and situate between Porthcurnow and Porthchapel, I was impelled to make a search for the mineral. Last July I succeeded in finding a cave near Porthcurnow, the small opening into which was partially hidden by masses of fallen rock; here I found after a rough examination traces of the mineral for which I was looking.