Pen Park Hole is a large cavern situated underground, at the edge of

Filton Filton is a town and civil parish in South Gloucestershire, England, north of Bristol. Along with nearby Patchway and Bradley Stoke, Filton forms part of the Bristol urban area and has become an overflow settlement for the city. Filton Church ...

Golf Course. The cavern was discovered accidentally in the 17th Century and the first descent was made by Captain Sturmy in 1669. The entrance is adjacent to the

Southmead Southmead is a northern suburb and council ward of Bristol, in the south west of England, bordered by Filton in South Gloucestershire and Monks Park, Horfield, Henleaze and Westbury on Trym. The River Trym rises in Southmead and flows south ...

and Brentry housing estates of north

Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...

. Access is tightly controlled by

Bristol City Council Bristol City Council is the local authority of Bristol, England. The council is a unitary authority, and is unusual in the United Kingdom in that its executive function is controlled by a directly elected mayor of Bristol. Bristol has 34 ward ...

. It was scheduled as a Site of Special Scientific Interest in 2016 on account of its geological origins, and its cave invertebrate community including the cave shrimp '' Niphargus kochianus'', which is normally known as a spring seepage or chalk aquifer species.

History

Captain Sturmy descended into the pit on July 2, 1669. Having roped down from an old lead mine, he and a miner companion descended using 25 fathoms () of rope. They found a large chamber which they illuminated with candles. Exploring further they found an underground river 20 fathoms wide. Seeing a passage above them, they had a ladder lowered which they used to ascend into the passage. Here they found what they thought was a rich mine "an abundance of strange places, the flooring being a kind of a white stone, enamelled with lead-ore, and the pendant rocks were glazed with saltpetre, which distilled upon them from above, and which time had petrified." After a few hours they ascended to the surface, but the unfortunate Captain Sturmy suffered from a severe headache for four days, developed a fever and died. This gave the hole a bad reputation and for a long time, nobody was willing to explore it further. On 17 March 1775 Reverend Thomas Newnam of Redcliffe Church fell to his death while attempting to

plumb Plumb may refer to: Arts, entertainment, and media * ''Plumb'', a 1995 album by Jonatha Brooke & The Story * ''Plumb'' (Plumb album), 1997 * ''Plumb'' (Field Music album), 2012 * , by Romanian poet George Bacovia People * Plumb (surname) * ...

the depth when the tree branch onto which he was holding broke. His body was recovered 17 days later. In 2007 a mast for mobile phone signals was proposed at the site, however a local campaign had this resited. In 2012 a housing development was proposed. This was rejected after further surveys of the cave showing that it was the only subterranean colony of the shrimp '' Niphargus kochianus''.

Description

The cave consists of some short climbs, and a few chambers, the last of which is a very tall rift chamber with a lake that changes height by as much as 20 metres. Side passages contain impressive

dogtooth spar Dogtooth spar is a speleothem that consists of very large calcite crystals resembling dogs' teeth. They form through mineral precipitation of water-borne calcite. Dogtooth spar crystals are found in caves, open spaces including veins and fractur ...

. The cave was formed by rising geothermal water (and is one of the best examples of a hydrothermal cave in the UK or Ireland), making it far older than other caves in the area, at around 190 million years old. The main chamber is high, long and wide. The lake within it is deep but the level fluctuates widely. The cave entrance is in a residential area and is protected by a steel plate for safety reasons. Access is under the control of Bristol City Council.{{cite web , url=http://www.penparkhole.org.uk/ , title=Pen Park Hole , publisher=University of Bristol Spelaeological Society. , accessdate=8 August 2016

References

External links

Pen Park Hole (2013) http://www.penparkhole.org.uk/ UK Caves - Pen Park Hole (2011) http://www.ukcaves.co.uk/cave-penpark Caves of Bristol Southmead