Between Sparrowpit and the head of the Winnats the old road from Chapel-en-le-Frith to Castleton skirts what is, geologically, one of the most important localities in Derbyshire. It runs along the side of a shallow upland valley, about 1200 feet above tide-level and two miles long, which is bounded on two sides by the curve of Rushup Edge and on the other two by Elden Hill, Windy Knoll, and other Limestone acclivities. One of the great faults of the Pennine chain traverses this valley longitudinally, the Yoredale strata having been thrown down to the level of the Limestone, so that the middle of the valley is the boundary between the Yoredale rocks, shale grits, and milestone grit on the north, and the Limestone plateau of Mid-Derbyshire on the south. The valley is completely encircled by higher ground; there is no egress for streams on the surface. Accordingly other modes of drainage are to be looked for, and they will be discovered in a numerous series of swallets situated along the line of the fault, the water that runs over the impervious shales perforating the Limestone as soon as it comes in contact with it. This shallow valley, in fact, is the gathering ground for the waters that pour into the abyss of the Speedwell Cavern, traverse Peak Cavern, and make their way to the open air at Russet Well and other springs at Castleton. That such is the case has long been proved by observations of the temperature and colour of the waters, and by tracing chaff and other things thrown into the upland streams. But there exist hardly enough data to establish the theory of the French speleologist, M. Martel, that Peak's Hole Water comes from Perryfoot, and the water of Russet Well from Coalpit Mine, near Sparrowpit. All that is definitely known is that these waters run through the massive Limestone for distances varying from two to three miles and reappear in Castleton, 600 feet beneath. Whether they unite into one or two large streams, which form considerable chambers and caverns in the inaccessible region beyond the farthest known parts of Speedwell and Peak Caverns, is an interesting question, that tempts one to answer boldly in the affirmative, since the action of underground streams in Somerset and Yorkshire seems to justify the assumption, if we take into account the extent of the vertical joints eaten away by the water in its descent of 600 feet, and the effects of periodical floods. In Somerset, in a situation exactly similar, two caves of 600 feet fall and 2000 feet horizontal measurement have recently been discovered by opening similar swallet-holes. Is there any hope of finding such hypothetical cavern or caverns here by exploring, and if necessary opening artificially, any of the swallets between Perryfoot and Giant's Hole? The investigations recently carried out by a friend and myself do not make us hopeful that if there are such caverns they will ever be made accessible.

We began our work at Giant's Hole, which opens in the bottom of a little gorge between Peak's Hill and Middle Hill. The brooklet that runs in at the cave mouth was very low, and we passed almost dryshod over the rough stones that cover the stream-bed for some 60 feet. Giant's Hole has an arched entrance about seven feet high, and the first part of the cave retains the same form. Then the walls contract, and the cave takes the shape of a deep and narrow canyon, cut through solid rock, with the stream coursing along at the bottom over little falls and waterslides and through pools that are not easy to pass without a wetting. One hundred and fifty feet from the entrance to the cave is a lofty rift, near the top of which an upper gallery turns west, the general direction of the main passage being southerly. Passing this, we followed the stream downhill for another fifty or sixty yards, and were then brought to a standstill by a partial choke. At this point a quantity of stones and gravel comes within two feet of the roof, and the water is dammed back in a pool a foot deep, so that there is barely a foot of clear space between water and roof.

Returning to the steep climb to the upper gallery, we scaled the wet and slippery rocks, and found ourselves on a shelf over the canyon. The shelf gave ingress to the gallery, which rose gently in a westerly direction, with frequent twists and turns, and then turned north. In 150 feet it divided. We scrambled on; but all the branches evidently approached the surface of the ground, becoming earthy, and we soon found it impossible to get any farther. This upper level, which for our purposes was of less interest than the lower, is incrusted with deposits throughout its length of 80 or 90 yards. There are stalagmite curtains and sheets of tufa on the walls, the older rocks on the floor are cemented together with a crust of polished stalagmite, and some of the boulders are covered with shining enamel. We found it best to use an Alpine rope in getting back to the lower level, the ledges underneath not being easy to find by candlelight. Outside the sun was shining brightly, and the light that streamed in at the cave mouth, through the ferns and flowers and grasses that encircled it, was stained a fairy-like green.

Continuing our way through the gorge between the sharp Limestone knoll of Peak's Hill and the bulkier Middle Hill, we followed a stream that comes down from Rushup Edge, perforates the Limestone base of Peak's Hill, and comes out on the other side at a small cave. In three furlongs this stream is swallowed under a cliff some 20 feet high, the ingress at present being through a series of holes, where the water makes an intermittent roaring, almost like the throb of a hydraulic ram, as if a siphon were momentarily discharging. Older rifts are seen in the same line of cliffs, and can be penetrated for 30 feet, but are now deserted by the water save at flood-time. Farther on is a deep depression in the hillside, big enough to engulf a house. It is supposed locally to have been produced by the falling in of a cave roof, but it is more probably an independent swallet, one of a series, nearly all funnel-shaped and long out of working order, that lie along a higher level in the Limestone than those that occupy the line of demarcation from the shales. The biggest of them is Bull Pit, which we come to later. Next to the last pair of large openings into which streams are running, and which may be called the Peak's Hill Swallets, since their waters rise out of Peak's Hill, we come to a large irregular series of trough-shaped hollows converging on another swallet at this same geological border-line. The openings here are all little ones. But the next swallet has a cave above it, into which we entered. It does not go far, but it has two ascending branches that can be traced to two small depressions in the Limestone where tiny affluents have percolated and cut for themselves little tunnels in the rock. The next swallet beyond this has but a small opening, although the hollow cut out by its rivulets through the shales is hundreds of square yards in area. An abrupt cliff walls in the hollow on the Limestone side, only a few paces from which are naked patches of Yoredale rocks, clearly defining the boundary of the two series.

We now came to one of the most interesting openings that we have met with. It lies about 200 yards north of Bull Pit. As often happens, immediately above the swallet, in the Limestone, is a deep chasm almost perforating the escarpment. At the base of the escarpment is a rounded archway with a turbulent stream running in. After securing a photograph we enter, and make our way down stream easily for a little distance; then the cave twists and narrows, and at a distance of 40 feet or so we are disappointed to find the channel too confined for us to force our way farther. Outside we had observed that the basin-shaped area had been flooded not long ago, and inside the vegetable dÉbris that was plastered over the walls and roof showed that the swallet must have been completely choked during the recent wet weather. But the peculiarity of this swallet was that the solid mass of rock through which the stream had carved its way was not ordinary Limestone, but beautifully veined and crystalline like marble, and its surface smooth and polished. It had very much the same appearance as the marmorised Limestone found in the neighbourhood of intrusive lavas, such as those near Tideswell. By the action of the water it had been sculptured into fantastic shapes; in one place a corner had been cut through and a small pillar left, joined to the rock at top and bottom. We scrambled with some difficulty into the chasm behind the swallet. At the bottom, on the same side as the existing swallet, was the broad and lofty arch of a cave, which went only a few yards in, otherwise it would have broken through the escarpment. Right above the keystone of the arch was a weathered group of stalactites hanging from a ledge, and under them the broken stalagmite floor of a tiny grotto. It is a rare thing to find such deposits in the open air, and doubtless it indicates that the chasm was formed by the destruction of a larger cave. A thick deposit of earthy mud covered the floor, and at one side a big hole penetrated this to a depth of six feet, the work of a stream that had perhaps not run for ages. This deposit, though dry, was so soft that I nearly sank through into the hole. We found four birds' nests in this cave mouth, with eggs and young in them, and were disappointed not to come across the egg of a cuckoo that flew out the moment before we entered. In the wiry grass not far away from the top of the cavity we discovered a lark's nest with two eggs in it.

Bull Pit lies in the wood just above this opening, nearer the road. It is a great open abyss, walled on three sides by crags of Limestone nearly a hundred feet high, and with trees growing all round the edges. This, no doubt, is a very ancient swallet that has not been in operation for ages—belongs, perhaps, to the same period as Elden Hole, which opens 200 or 300 feet higher, a mile away, on Elden Hill. A little way on, near Perryfoot, we come in sight of another very ancient cavity, on the side of Gautries Hill. It is a gaping pit about 70 feet deep, with a noble arch inside, spanning the entrance to a broad cave. At present the cave mouth is silted up with sand and clay. All these rocky openings are the lurking-places of beautiful ferns and mosses; the feathery fronds of the Limestone polypody, the late primroses, various saxifrages, and the delicate foliage of herb robert making a brave show. The wilder birds take refuge there. A crow flew out of the hole on Gautries Hill, and one day on approaching Elden Hole I was startled by a dense cloud of jackdaws, more than a hundred, suddenly rushing out. Farther down, from 50 to 100 feet lower, a host of starlings had built their nests on the walls of the chasm. Disturbed, they came flying up in twos and threes, beating the air in painful efforts to wing their way straight up and out of the hole.

At Perryfoot a stream is engulfed which M. Martel considers to be the source of Peak's Hole Water, and to be identical with the stream that flows through the inmost passages of Peak Cavern. It now runs into a cleft that is too small to be explored. But at a comparatively recent date it was swallowed in a number of large fissures in a crescent-shaped wall of Limestone 100 yards away. Most of these openings are impracticable, but at the extreme east I had already reconnoitred a promising cleft which we now proceeded to examine thoroughly. This complicated swallet, with the passages behind it, is known locally as "Manifold." Going east for 35 feet, the fissure divides, one passage striking up towards the surface and the other turning south. We soon had to crawl, the passage being very low, narrow, and lined with objectionable stones. After 30 feet more we came to a wider place, with a sort of chimney on one side. Here was the sole mark of humanity that we found in this cave, a stake that had apparently been used to climb into the chimney. Nothing was gained by climbing it, so we squeezed our way along the main passage. Now the tunnel grew into a high but narrow canyon where we could stand upright, then it dwindled to a tunnel again, generally descending, but occasionally rising in what was once a siphon. We passed one or two branches, at the most important of which the principal tunnel curved to the left and descended a little more steeply over some small ledges and basins brimming with water. We began to feel sanguine about the wished-for cavern, but presently the diameter of the tunnel grew so small that we could not advance another yard. My companion was some distance behind with his candle out, and I would not make a move until he had got it relighted, the consequences of both candles going out at once being unpleasant and possibly dangerous. For a long way we could not turn round, and had to crawl feet foremost. Just after repassing the junction my companion shouted that we were going wrong. He did not recognise the passage. I remained at the junction whilst he went farther and ascertained that it was the right channel after all. Then I examined the branch. It ascended 20 feet and then divided, the left branch, which was earthy, plainly striking up to the surface, the right branch going back towards the swallet. Undoubtedly there must be quite a labyrinth of dry water channels to correspond with the numerous series of openings in the cliff, but the one we explored seemed to be the largest and most practicable. Very tired and hot, not to mention the dirt, we made our way back to the exit, glad to feel that our day's work was done.

The one thing that had impressed us most during our explorations was that all these swallets and water channels are cut through solid rock. Only when the rocks are shattered or disintegrated, as in the cases alluded to in Somerset, would there be any possibility of enlarging a swallet artificially. And though we had penetrated to a distance of 400 feet at Manifold we had not found the passages growing more roomy nor enlarged by the accession of tributaries. So far, the prospect of opening up the large fissures and chambers that must surely exist deeper in the rock seems unfavourable, unless the main channel of Giant's Hole can be unblocked.

E. A. B.