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St. Cuthbert’s Swallet

LAKE CHAMBER: problems solved and unsolved

a)         Problems solved

Water leaves the main Stream at the site of a dig a short distance upstream of the Dining Room.  In low water conditions the dig can swallow the whole of the Main Stream.  Underneath Cerberus Hall is a pool of variable dimensions, usually about twelve feet long, one to three feet wide and three feet deep.  Water enters the pool through an impenetrable crack about two feet above the water level at the eastern end of the pool and leaves through a mud choked sump at the north-west end of the pool.  It was thought by many leaders that water in the pool came from the mainstream and went to the lake, but this view had its opponents.

Water temperature and hardness measurements by the author showed that the Cerberus Pool must certainly have come from the Main Stream, and the Lake was thought by the author to be made of water from the Main Stream mixed with percolation water from another source.  This was proved to be true when Pyranine was added to the sink at the Main Stream on January 26th 1968.  The connection with Cerberus Pool was proved visually, and a fortnight later the water in the Lake was seen to be coloured with Pyranine, to the surprise of the author who had expected the dilution to be too great for visual detection.  Thus it was proved that water from the Main Stream flows via the Cerberus Pool to the Lake – to the North, flowing in the opposite way to the Main Stream.

b)         Problems unsolved

No pattern has yet been found to explain the variation of the water level in the Lake, and the possible connected variation of the water level of the Cerberus Pool.  The Lake would appear to be fed from below, although it does receive water from a heavy drip.

It would be extremely difficult to prove conclusively that water from the Lake does not resurge into the bed of the Main Stream somewhere downstream of Plantation junction, but the probability is that the water from the Lake does not re-enter the known system.

It is not known whether the pools discovered last year to the north of the Lake are part of the drainage from the Lake, or part of another inlet to the Lake.

A passage in Lake Chamber remains unexplored; the entrance is usually submerged. It should not be neglected because of the possibility that the Gour-Lake Fault is breached here.  When the Lake has been completely empty a gravel floored passage has been seen at the bottom.

c)         The possibility of an undiscovered breach of the Gour-Lake Fault.

The intermittent streams draining the area west of Rocky Boulder Passage and north of Curtain Chamber are not thought to enter the known Main Stream, and water from the Lake would seem likely to breach the Gour Lake Fault.

The diagram published by D. Irwin (B.B. No. 241 p 47) also raises the possibility of two separate drainage systems being developed along the same fault, with an exit at the Duck and an exit somewhere between marble Hall and the Lake.

The unknown breach at Lake Chamber, with drainage from the areas mentioned above also feeding the Lake, or it may be that water from the Lake has to flow further north along the fault until the breached is reached.  The author favours the later possibility because the hardness is so close to that of the Main Stream, indicating a mixture with relatively little percolation water.  Another possibility is that yet another breach for the drainage not accounted for. The answer may not be known for sure until the Sump or the (dry) breach of the fault at the Dining room Dig is passed. It will be ironic of an open hole into known cave is discovered from the other side of the fault.

R.D. Stenner
18th April ‘68

APPENDIX – Results 10-2-68.


Concn. X 105(M) (M= ppm CaCO3)




Permanent Hardness

Temp oC

Main Stream Dining Room





Pool, Cerberus Hall










Pyrolusite Stream, Gour Hall






Precision of results:

Bicarbonate ± 1.5 ppm Permanent Hardness ± 2 ppm Calcium ± 1 ppm Temperature ± 0.03oC

St. Cuthbert’s Swallet – Latest Discovery

On Saturday th April 1968 Mike Luckwill discovered a new chamber in the CANYON SERIES.  He suggested that the new chamber be called FORBIDDEN CHAMBR as to reach it means passing a nicely decorated passage which would soon be ruined.  The chamber is said to be quite big.