OUCC Proceedings 2 (1963)

The open pot is situated in a large shakehole, south of Bullpot Farm, Casterton. It can be descended without tackle by a traverse on grass to a tree on the west side, whence a 40 foot handline is helpful for another downward traverse to a cave entrance at the south-west end. Along this passage, and down a chimney, and one emerges in the South-East Passage. Leftwards leads to the bottom of the open pot, whilst right, through a low crawl, leads to the Main Chamber ('32 Cavern). Two other routes lead from the open pot. To the north, a climb into a passage above the water sink, and then down a hole on the left, leads to a 35 foot pitch (ladder required). At the foot of the ladder is Flood Fall Chamber in North Avens Passage. To the south-west from the open pot, a descent through boulders leads to the head of a 60 foot rope pitch (belay to the iron bar). The pitch is in many short stages and can be free-climbed. Near the bottom of these drops, a passage on the left leads to a climb up boulders to the Crossroads. Continuing down the drops, the stream is met at a right turn, and a traverse leads to a ledge at Four-Ways Junction. Climbing down and following the stream, a 25 foot pitch is reached, which can be descended using a ladder (20 foot belay in roof), or a rope (40 foot, same belay), or free-climbing depending on the volume of water flowing. In all cases, traverse out and down. Below is a chamber and another pitch into a chamber. This latter pitch is avoided by a traverse high on the right wall, leading to the far side of the chamber, whence an easier descent is possible. From here the stream flows into the canal.

Just before this, an eyehole on the right leads into a gallery, Long Gallery, above the canal. To the right, along Long Gallery, a stream is reached, flowing south. Downstream the roof meets the water. Upstream is over shingle banks to a pool, which in very dry weather has an air space and is passable to Lake Chamber. From the left, at the eyehole, along Long Gallery, a hole leading to the canal is reached. Descent of this hole by free-climbing gives access to two holes, the left-hand hole being the easiest into the canal. Upstream is a sump; whilst downstream the water is followed apart from shingle banks, until the roof lifts. At a large pothole take the upper level to the left, over the hole and on to Cairn Chamber and a crossroads.

The right-hand passage leads over a pool to some low, crawly ox-bows. The left-hand passage chokes to the left; but to the right a dry stream passage runs parallel to the stream passage (which continues straight on at the junction, whence water is soon met). The stream passage and the dry passage both end in the final sump chamber. The stream passage contains a duck, and there is one connection between the routes. Back in Long Gallery, continuing past the hole in the floor, the passage drops to a low, choked crawl at a junction. Here a climb on the left up an aven leads into Pool Passage, which, after a squeeze at a pool, comes out at Four-Ways Junction. (This is the passage on the left as the junction is met from the entrance.)

In the Main Chamber, a hole on the right can be descended, or use can be made of the easier chimney on the nearside of this. At the bottom is the Crossroads, where many ways meets, see diagram. Passage A, high in the right wall, leads to the roof of one of the chambers in the South-West Entrance Passage (i.e. the one containing the 60 foot rope pitch). The next passage on the right is a climb down boulders to the bottom of the rope pitch in the South-West Entrance Passage. The third and fourth passages lead to North Avens Passage. The latter emerges in a small chamber to the side of this passage, and also containing a passage to the right. This connects with Four-Ways Junction. The passage on the left at the Crossroads leads to T-Junction. To the left, the passage, Avens Passage, leads to two large avens. To the right, North Avens Passage leads past two junctions to a large chamber containing an antechamber, Flood-Fall Chamber, where the North Entrance Passage descends.

Onwards, along North Avens Passage, the passage ends at a flowstone slope, but two holes on the right drop down into Flowstone Rift. After proceeding along this for about 15 feet, a long climb up the flowstone on the left leads to Rimstone Chamber, containing a number of gour pools. Up to the right, a climb up the narrow part of the passage leads to second gour chamber, Moon Chamber, with another chamber above this.

In the bottom right-hand corner of Rimstone Chamber, a descent over flowstone leads into the roof of Lake Chamber. A sloping descent on the left leads to a shingle bank above a lake. In very dry weather the level of the lake falls. A fall of about 15 feet will make negotiable the passage to Long Gallery, which is at the bottom of the lake. Upstream, a duck in a pool opens into a small chamber with an ox-bow crawl to a large stream passage. On the left, a small hole gives access to a large shattered aven. Onwards, the passage ends at a sump. Returning there is a gallery on the left, which returns downstream in the roof of the main passage. The passage is known as '49 Cavern, after the year of its discovery.

G. Stevens

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