The cave has been proved to extend as far as the village of Priddy, about two miles off, on the Mendip hills, by the fact observed by Mr. Beaumont, that the water used in washing the lead ore at that spot, in his time, found its way into the river Axe, and poisoned cattle in the valley of Wookey. And this observation has been verified during the last few years by throwing in colour and chopped straw. The stream at Priddy sinks into a swallow-hole (Fig. 1), and has its subterranean course determined by the southerly dip of the rock, by which the joints running north and south afford a more free passage to the water than those running east and west. The cave is merely a subterranean extension of the ravine in the same line, as far as the swallow-hole, and all three have been hollowed, as we shall see presently, by the action of the stream and of carbonic acid in the water. _The Goatchurch Cave._ The largest cavern in the Mendip hills is that locally known as the Goatchurch, which opens on the eastern side of the lower of the two ravines that branch from the magnificent defile of Burrington Combe, about two miles from the village of Wrington, at the height of about 120 feet from the bottom of the ravine. After creeping along a narrow, muddy passage, with a steep descent to the west, at an angle of about 30°, you suddenly pass into a stalactitic chamber of considerable height and size. From it two small vertical shafts lead into the lower set of chambers and passages; the first being blocked up, and the second being close to a large barrel-shaped stalagmite, to which Mr. Ayshford Sanford, Mr. James Parker, and myself fastened our ropes when we explored the cave in 1864. The latter affords access into a passage, beautifully arched, and passing horizontally east and west, and just large enough to admit a man walking upright. At the further end numerous open fissures, caused by the erosion of the joints in the limestone, cross it at right angles, and pass into several ill-defined chambers, partially stalactitic, but for the most part filled with loose, bare, cubical masses of limestone. Two of the transverse fissures lead into a large chamber, at a lower level. At its lower end, on crawling along a narrow passage, we came into a second chamber, also of considerable height and depth, at the bottom of which the noise of flowing water can be heard through two vertical holes, just large enough to admit of access. On sliding down one of these we found ourselves in a third chamber, which was traversed by a subterranean stream, doubtless in part the same which disappears in the ravine, at a point eighty feet above by aneroid measurement. The temperature of the water, as compared with that of the stream outside (49° : 59°), renders it very probable that, between the point of disappearance in the ravine and reappearance in the cave, it is joined by a stream of considerable subterranean length, since the water could not have lost ten degrees