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Tynnings Barrows Swallet

B.B. Supplement – Late Extra

As many members will by now be aware, the dig in the choke at Tynings Barrows Swallet has gone, yielding at least 3000 feet of passages of which 1,600 feet is streamway and the remainder is side passages.

Members of Axbridge Caving Group looked at the site after it collapsed following the ‘68 floods.  It dropped very rapidly via a clean washed streamway to a gravel cum boulder choke.  However, the farmer, Mr. Paton, decided to fill the collapse in.

Early in 1976 Snab, of the Grampians, having got to know the farmer fairly well was able to negotiate access to the site, and digging started.  On April 18th, only after only five hours of diggings the cave was open once again, various members of the B.E.C. and Grampian having had a hand in the excavation.  Between then and the summer much activity saw a concrete pipe entrance in position, the swallet nearly filled up again, and many boulders below semi-stabilised. Digging at the old choke then started, and, although rather sporadic, little effort was needed for the breakthrough, which occurred on February 15th this year.  A small group of B.E.C. and Grampian cleared the choke, enlarging it considerably from the far side.  On this trip the present bottom of the cave was reached.  Seven other trips and two weeks later many of the side passages have been explored, the survey has been started, and the bottom is being dug.

Descent of the concrete pipe is by ladder, and a second ladder pitch follows immediately into a chamber of mud and large, loose .boulders.  A river of mud then follows – a couple of collapses caused by the heavy winter rains after last years drought have deposited tons of very liquid mud into the upper reaches of the system.  Already this has reached the breakthrough and is destined to go much further.  Only the passage of cavers will keep this upper section open.  The breakthrough is steep, but no longer tight as it was originally.

The main way on downwards is fairly obvious, the passage quickly increasing from a grovel and stoop to walking size, and being joined by three inlets.  Passage sizes especially height, increases further as the climb to an upper series, Paton Place, is passed.  There is a lot of collapse in this region, until the water drops down the Aardvark Trap.  The way onwards, over the Trap, becomes narrow and low, with gour flooring and old, broken stal.  After a small sump and an inlet on the left the passage size increases dramatically and drops steeply down to Pyramid Pot.  In this second large section there is a further collapse, due in part to faulting. However, since all the rock is very shaley (the cave is formed almost entirely within the Lower limestone Shales) the debris has been washed away.

Below the pot, the way on is initially smaller, with the passage zig-zagging, first on the strike, then on the dip, back to the strike and so on.  There are only a couple of places between here and the end where it is necessary to crawl, each for a short distance.  Much of the passage is a high, narrow, strike orientated rift. More stalagmite is to be seen in this lower section, though it appears to be old, and is either broken, very dead, or undergoing re-solution.

Near the present terminus ‘A Day’, there is a gradual build up of gravel deposits, until finally it nearly fills a dip section of passage to the roof.  This is being dug at present, but the excessive amounts of water this winter make progress difficult.

Since the initial breakthrough nearly all the side passages have been fairly well explored, though there are still several loose ends.  The whole of the roof from 'A Day' to Pyramid Pot has been thoroughly checked, and there seems to be no possibility of extension either over the final dig, or elsewhere, from here.  Drunken Horse Passage, an inlet entering from the North, in the lower section of stream passage, goes for about 300 feet to a tight section.  Its stream is full of organic matter.  The lower inlet at the Cheese Grater, a heavily stal-ed narrow section of rift, becomes tight after a very short distance.  Holes among the stal in the zig-zags appear to close down just above the general roof level.  However, a large passage with a wide flow of stal in the same area has been pushed through two low sections to a narrow sharp rift.  Here the spirifer shells, which tear clothes and bodies in other parts of the cave, actually prevented the explorers from continuing along the rift.

The Aardvark Trap has been explored for some distance to a chamber, and then a sump.  This may correspond with the sump in the main passage, above Pyramid.  Just below the latter sump is at least 400 feet of narrow rift passage leading off - Velcro Passage, very appropriately named.  It leads to Hairy Chamber, and also a high level passage with an impenetrable connection with the Upper Series of Paton Place.  This has proved to be an extensive series containing a little, very good stal.  Several skeletons of rodents and some bat-bones (there are also bat bones in the lower part of the cave).  One of the skeletons has already been totally destroyed by someone's boot, all the more alloying considering the handful of people who have actually gone down the cave so far.  The stal will not last long.  Passing via the large Dragon Chamber, at one of the extremities of this series, leads back to a rift just below the breakthrough, so there are two possible routes into the series.

Much work remains to be done. Apart from the exploration, which seems almost complete down to 'A Day' already, there is the new dig itself.  Although this looks very premising it is likely that it will require a considerable effort - much more than the breakthrough did.  The stream can be seen running along a strike passage, over gravel, as far as a nife beam will penetrate in the inevitable mist. The bedrock floor is probably at least ten feet below this level.

The survey of the main passage to the bottom has been started, and the initial line should not be long in coming.  However, the very nature of many of the inlet passages, narrow, twisting, and with an incredible abundance of the sharp, Spirifer fossils, precludes speed or accuracy, and we will probably go for the former, except for the major passages.

Access is at present restricted to members of the digging team and their guests.  This situation will remain until work in the cave, excepting digging, is complete.  Considering that the cave was totally closed for eight years, we are extremely fortunate now that it is open at all.  It is to be hoped that prospective visitors will respect the restrictions and bide their time.  Access arrangements are due to be worked out with Mr. Paton.  Any enquiries for the future should be addressed to the Belfry.

Graham Wilton-Jones.

 

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