The Wrens Nest NNR Tour - Seven Sisters Caverns
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Difficulty:
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Size: 
(small)
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This cache is one in a series which I have set up at various places of interest within the Wren's Nest National Nature Reserve (NNR) located to the north west of the town centre of Dudley, West Midlands, England. I would like to thank the Wardens & DMBC for letting me place these caches and all the help given :)
This cache is situated at 'Seven Sisters Caverns'.
Wren’s Nest derives its name from the Old English word Wrosne, meaning “the link”. This may relate to its topographical position on the boundary between the Severn and Trent watersheds.
Wren's Nest is a classic geological site of exceptional importance, being one of the most notable geological locations in the British Isles and visited and studied by geologists from all over the world.
About 420 million years ago, tropical seas covered the area where Dudley now stands, with coral reefs inhabited by trilobites, crinoids (sea lilies), brachiopods and many other creatures. Their remains may be found today as perfectly preserved fossils in the limestone rocks at Wren's Nest, collections of which occur in museums throughout the world. Over 700 types of fossil are known from Wren's Nest, 186 of which were first discovered and described here, and 86 are found nowhere else on Earth.
Wren's Nest played an important part in the very development of the Black Country, not least because Abraham Darby, Father of the Industrial Revolution, was born on Wren's Nest in 1678. Dud Dudley (son of Lord Dudley) had, by 1665, developed a process to smelt iron with coke instead of charcoal, but local charcoal burners, who feared that their livelihoods might be threatened, destroyed his furnaces. Darby developed Dudley’s work and perfected the process in Coalbrookdale by 1709.
For centuries the limestone was quarried for building stone and for use as an agricultural fertiliser. Huge quantities were excavated during the industrial revolution to act as a blast furnace flux in the Black Country's iron and steel industry, leaving Wren's Nest honeycombed by caverns and underground workings. The caverns known as the Seven Sisters are the spectacular openings to the workings, which formerly descended 100 metres below the hill. The workings were originally connected by underground canal to the Dudley Tunnel. Seven Sisters caverns, so called because originally seven pillars supported the roof of the old workings at this point. Only five pillars now remain. The 'pillar and stall' method of mining can be clearly seen.
During the height of the Industrial Revolution, up to 20,000 tons of limestone were removed annually to act as a flux in the many local blast furnaces. This activity ceased in 1924, leaving the area honeycombed with great quarries and caverns, some going down 100 metres below the hill to underground canal basins. However, the site would never have been so well exposed without such excavations and few would have known the history of the rocks. It was during this period that many of the best fossils were found, the most famous being the Trilobites. One of these, Calymene Blumenbachii, was so common that is became nicknamed the 'Dudley Bug' and featured on the town's Coat of Arms until 1974.
When the quarrying and mining ceased, the hill was abandoned and left to nature. It is now colonised by grassland, scrub and Ash-Elm woodland. The limestone rocks support plants that are adapted to lime, including county rarities such as Autumn Gentian, Small Scabious, Common Gromwell and Bee Orchid. The woodlands are home to birds like Sparrowhawk, Stock Dove, Tawny Owl, Green and Great Spotted Woodpeckers, and Nuthatch; the caverns offer important roost sites for several species of Bat, whilst the locally uncommon White-letter Hairstreak butterfly survives on the elms.
A major roof collapse occurred in October 2001, which, if left unchecked, would have resulted in the loss of the Seven Sisters. A project co-ordinated by the Geotechnics team secured funding from English Partnerships Land Stabilisation Programme to fill in the lower caverns and to temporarily fill the upper daylight gallery with stone to protect it from further collapse. The project was accepted as a Demonstration Project in the ODPM Constructing Excellence scheme and achieved the maximum score under the Considerate Constructor Scheme. Further feasibility studies are being commissioned to consider the best ways to stabilise the Seven Sisters and to realise the tourism potential of the site.
In October 2004, Wren’s Nest and Castle Hill were declared a Scheduled Ancient Monument in recognition of them having the best surviving remains of the limestone quarrying, mining and processing industry in Dudley. This includes the last remaining surface opening limestone cavern in the world – the Seven Sisters.
This can be a high Muggle area for dog walkers so major stealth is required!
Please remain on designated paths and observe any path closures or diversions. It is strictly prohibited to enter the areas inside the safety fences.
Lastly, if you are going to collect any fossils whilst here, can you please abide by the Fossil Collecting Code!
1. For your own safety please
DO NOT climb on the rock
exposures. Rock faces can be
unstable and dangerous.
2. The use of hammers or other
tools on the reserve is STRICTLY
PROHIBITED. Never collect
fossils directly from rock faces.
3. Fossils may be collected from the
loose material at the base of
slopes. Please only take away a
few small representative samples.
4. For help with identification please
contact the Warden Service on
01384 812785 or Dudley Museum
on 01384 815575. Remember to
keep a note of the exact location
your fossil was found.
5. If you no longer wish to keep your
fossils, remember never throw
them away! Donate them to the
Museum or the Warden Service
for others to enjoy.
THANK YOU
****THE HONOURS****
FTF - Greyboots & andycpuk
STF - lathama
TTF - The.Darlaston.Duo.s
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Additional Hints
(Decrypt)
Ol lbhe srrg ng gur raq bs ivrjvat cyngsbez, ernpu nebhaq naq unir n srry!