Belfry Bulletin Number 021

Belfry Bulletin BRISTOL EXPLORATION CLUB Vol. 3 No. 21

March 1949

First a Correction In the last BB we announced that Don Coase was supplying photographs for sale by the Club. This should have read, “Don Coase and W.J. Shorthose are doing the work for the Club”.

By the way, these photographs are copyright, and must not be reproduced without their permission.

Apologies to all concerned, for the omission. Editor //=//=//=//=//=//=//=//=//=//=//=//=//=//=//=//=//=// BATS We have received from the Assistant Hon. Sec. of U.B.S.S. the following letter which we are printing in full: Dear Sir, Would you be so kind as to bring to your members notice that following: Members of the Bristol University Speleological Society have marked a number of bats in the Mendip Caves, in connection with research on the habits of cheddar male. The bats are marked with a metal tag on one wing bearing the words ‘U.B.S.S.’ and a number.

It is earnestly requested anyone finding such bats should not injure them or remove their tags. We will however be much obliged if the finder makes an accurate note of the following details and sends it to the Sec. of this Society.

1. Letters & numbers on bend.

2. Cave (& part of Cave) where bat was found.

3. Date of finding Any such information will be of great value to us.

Bats may also be found bearing tags with the following words on: ‘Van Schaik- Zool. Mus. Utrecht. Holland’ and a number.

Information concerning these should be sent to The Zoological Museum Utrecht Holland Or to the Sec. of this Society.

Thank your for your co-operation, I am Yours sincerely H. Fright, Assist. Hon. Sec. //=//=//=//=//=//=//=//=//=//=//=//=//=//=//=//=//=// The Caves and General district surrounding Burrington Coombe in Hydrology. By P.A.E. Stewart.

Burrington Coombe is one of the finest cave areas on Mendip. In its limestone flanks lie two Master Cave systems whose hydrology is one of the most fascinating studies that I have yet encountered.

Theses can be classified as the systems of resurgences at Langford and Rickford.

Taking the Langford Master Cave first, one can included definitely the Swallets of Read’s Cavern, Bos Swallet, Drunkard’s Hole, Rod’s Pot and Bath Swallet.

Sidcot Swallet is rather indeterminate – the general direction of the cave trends towards Langford, but, however, the present active waterway trends towards Rickford. Sidcot also has not a great altitude above the water table and it is doubtful whether the mechanical erosion of the water would be capable of carrying a passage the distance to the Master Cave (Langford System).

BB21/2 The Rickford Master Cave may be extremely large, taking water from Goatchurch Cavern and the other main sink in Lower Twin Brook, and East Twin Brook Swallet. It must also have taken the drainage from Plumley’s Hole, Aveline’s Hole, and Foxes Hole as well as the roadside swallets on Burrington Ham when water was flowing down Burrington Coombe.

Mr. Balch of Wells also puts forward the interesting theory that water at the bottom of Cow Hole also issues at Rickford Rising - however, this water may possibly issue at a rising between Ubley and Compton Martin.

Sidcot may again join the Goatchurch waters to emerge at Rickford.

An analysis of the Swallets follows: Langford Swallets.

Read’s Cavern. Water issues from the sandstone, crosses the shale band and sinks naturally at the foot of the cliff on the south side of the track from Burrington to Rowberrow. When there has been little rain the stream sinks further up the valley in a subsidence that may in time become a passable swallet. This water appears in ‘Z Alley’, sinks again and reappears later in the system.

When there has been more rain, the water sinks at the western base of the cliff, reappears in the present stream way at the western end of the Main chamber and can be followed down through an intricate maze of passages to the ‘Tee Slot’. It was for the purpose of exploring this system that a party led by the author descended the cave on 30/11/47. The ‘Tee Slot’ was reached, but due to size, the author could not penetrate further. Pat Browne then undertook the lead and the exploration was carried out on to about the same distance from the entrance to the ‘Tee Slot’. More massive limestones were reached than are obtainable in the Upper cave and water - very probably from the ‘Z Alley was encountered. Numerous choked side passages and sinks were encountered and signs of flooding were noticed. This lower system (which was subsequently named ‘B-S’ System), is more stable than the upper parts of Read’s, although a hectic few moments were enjoyed when a bank of scree began to avalanche in the best traditions of London Escalators.

Between the upper and lower systems however there is a zone of highly unstable rock, each rock supporting three or four others and an objective contemplation of the scene roundabout brings on a violent dislike of movement!!

About 300ft. of vertical depth was obtained at the furthest point – this leaves about another 100ft. to the water table, leaving one to imagine that the flood marks may be the result of constrictions of water passages.

The horizontal development of the cave is not large and the inference – borne out by other observations in different areas, is the mechanical erosion carries the cave down to the water table in a fairly constant distance, this being proportional to the strata dip.

If this is so, the Langford Master Cave must be at the present moment in phreatic state fed by vadose swallets.

Bos Swallet. Is a tight crawl with little interest to show hydrologically.

Drunkard’s Hole. Is a tight rift development with two small final chambers.

Rod’s Pot. Opened in 1944 by R.A.J. Pearce drops from O.D. 575ft. at the entrance to about O.D. 390ft. (scaled from a map in U.B.S.S. Proceedings) – this give over 190ft. of vertical depth to the water table, although the water table might be perched near this swallet as the impervious rock outcrops close on the 500ft. contour in Mendip Lodge Wood north of the Pot. There is about 200ft. of horizontal development in this cave and the terminal chamber is quite large so more may be expected from this system.

Bath Swallet. Has not as yet been completely opened, one or two chambers have been entered but progress has been very slow.

There are one or two other hollows and digs about the U.B.S.S. headquarters, but nothing of any size as far as I know, (15/2/49.). Professor Palmer obtained some interesting results in some water table determination tests carried out with the Megger Earth Tester at Link Batch, but these results may be purely local. He has also carried out a search in the region of Warren House on the north side of Dolebury Warren.

Rickford Swallets Goatchurch Cavern. This from its structure seems to have been the subject of phreatic development – it has the general lattice structure of the type – it is a bedding plane cave with three (so far) levels of development known. It is supposed to be about 220ft. aneroid depth, so there is about 80ft. before one reaches saturation level (in Rickford Rising). Incidentally the stream in Goatchurch Water Chamber was running recently when no water was present outside the Waterworks Enclosure in Twinbrook. This rather knocks on the head various salt tests carried out when water was sinking at the dig half way down the valley.

It may be that the water seen in the ‘Sump’ is not encountered elsewhere in the cave.

BB21/3 The Dig that someone has carried out near the rock face in Twinbrook leads to a rift but is still too tight to follow.

The Large Crater near Sidcot leads to Sidcot secondary system – the water possibly leading to Rickford.

Plumley’s Hole. This is a vertical shaft in the quarry above Mendip Gate. It is marked on the Ordnance Survey 6” 1931 as Plumley’s Den. This is a misnomer, Plumley’s Den being Foxes Hole. This has finally been settled and the new name will probably appear on the latest O.S. Maps – when they appear!! It may be a natural shaft on a fault; this can be seen in a shaft further up the Coombe above Aveline’s Hole. There is no report of any water in Plumley’s so it is of no interest in the present hydrology.

Aveline’s Hole has streams apparent at two points. At the far end of the main chamber in wet weather, and also in the lower series. This may be the same stream. Where it goes now is rather dubious - the original cave itself seems to be of strike development and there is much more to find in Aveline’s if the general run of the cave is followed. Aveline’s entrance is at 400ft. O.D. giving 200ft. of depth to saturation level. The source of the stream in Aveline’s is also a mystery.

The shaft above Aveline’s has loose earth at the bottom, and if dug may go further - there is no stream - it was probably a feeder swallet in the formation of the Coombe.

Whitcombe’s Hole is likewise of no importance.

Smaller Swallets formed at a later date are Tratman’s Dig and other minor digs opposite East Twinbrook.

Foxes Hole (Plumley’s Den) is an early formation Swallet. In the lower of the three chambers, stalagmite covers a rift down which a small steam flows Toad’s Hole and Frog’s Hole the origin of those mined shafts is a mystery.

Pig Hole is a mined adit into a rift of bedding plane formation.

A Large Rift in the woods behind Pig Hole.

East Twinbrook Swallet. This cave has three chambers, the third recently opened by Sidcot Speleos – it is however in loose rock and until it reaches the limestone proper and finishes with the passages beds to the shales, we can expect no large system. This cave has however fine possibilities and should reach more solid rock within about another 300ft., the small digs on the other side of the road should join the East Twin System. East Twin is on the 500ft. O.D., so it has quite a depth to go.

The formation of the Coombe is rather a moot point; however we can assume that, unless there has been a massive earth movement or a concentration of the Armerican/Lower Severn Axis movements hereabouts, Mendip top was some thousands of feet higher that it is at present, from the strata angle. Thus at the time the Coombe was formed there is every chance that it was in the same state as G.B. is today. Cheddar according to Martel was formed in that way. If so we can put an approximate date to all the swallets in the Coombe.

Probably the cycle is: 1. That the Coombe was phreatic. 2. That the mud filling was washed out and into the bottom swallets.

E.g. Aveline’s. 3. That the surface was eroded and the roof fell in; 4. That the phreatic system was modified by vadose streams; 5. That small vadose systems were formed.

The fitting of these caves into the hydrological formation of the district is largely hyposethis and the rest imagination, with about 10 p.c. field observation – it is like trying to work out a jigsaw from half the pieces present. It is however an extremely interesting subject.

P.A.E. Stewart. ********************************** Personal We are delighted to announce the forthcoming wedding of Reg Hazell and Miss Beryl Herman. They are to be married at St. Mary Redcliffe on Thursday 21st April. Thus two B.E.C. families become linked.

Although not a caver herself Beryl is sister of our popular member Stan Herman. *********************************** The Editor has received an anonymous Letter signed by "Becite, who will be interested to know that such letters are not considered by the Committee or the Editor of the BB. If any member wishes to make any criticism we shall be only too glad to receive it.

D.H. Hasell Hon. Ed. ***********************************

BB21/4 Fresh New From the Divers at Peak Since the last BB the following information has come to hand: - “Four members of the C.D.G. again entered the Buxton Water Passage and advanced beyond the previous point till after approx. 3,000ft., a second sump stopped progress. Plans are in hand to tackle this shortly. The dressers who had also passed a duck in Speedwell Water, linked up after 1,500ft. with the Buxton Water Passage. Several side passages await attention”. Although the London Section of B.E.C. is ‘officially’ dormant, it is seen by the above that our members there are certainly going places. *********************************** There has been a big run on the Stoke Lane pictures, but there are still some left. Send in for a selection as soon as you can, and be sure of getting a number to choose from before they are gone. *********************************** London Section News.

In addition to the splendid news from Peak, the London section in addition to a very full local programme, details of which will be published when available, is planning a week on Mendip the dates being from 23rd. July to 1st Aug. The final details will be printed when I have them. *********************************** The following has been received from Pongo Wallis.: ‘The following is taken from the description of ‘Natterer’s bat’ in ‘British Isles’ by Brian VeaseyFitzgerald. It seems to apply very well to the inhabitants of the Belfry.

The Natterer has much hair on its face. It goes into caves for hibernation at the end of September and does not resume activities until the end of March. There is no segregation of the sexes during hibernation.

Hibernation is very fitful as there is much disturbance in the roost; so many occupants are woken before hibernation is really over.

The Natterer is very gregarious and sociable, living in large colonies. It is little affected by the weather, though it dislikes a cold east wind. The time of its evening flight is very variable, on many days in the summer, coming out before sunset. There is much squeaking before emergence.

It alights head up or down impartially. If the latter, a somersault before alighting, but it is not good at this manoeuvre and often misses its foothold. It makes a long and careful toilet.

It drinks on the wing, and squeaks continually in flight. The squeaks are loud and can be heard by by anyone with norma1 hearing.

It is found in the vicinity of water, but is not water loving.

It is generally but locally distributed in the west of England. **************************************** There are two new Caving Books to be published shortly. Both are on the Laxaux painted caves. Pongo who send in this information will doubtless review them in the BB at a later date. ***************************************** Owing to lack of space ‘The Hon. Sec’s Postbag’ feature has had to be held over until a later issue.. ****************************************** The Birmingham Cave and Crag Club have during the last month spent a weekend as our guests on Mendip. They visited Swildons Hole and G.B. ****************************************** T.H. Stanbury, Hon. Sec., 74. Redcatch Road, Knowle, Bristol. 4.

W.J. Shorthose, Hon, Sec. London Section, 7. Marius Mansions, Rowfant; Road, Balham, London, S.W.17.