Dorset is not a caving region one might think of but there
is enough in the county to interest anybody with a speleological
bent. As many will know Portland is part
of the Jurassic Coast world heritage area and it is rather
nice to know there are some significant caves in it. On the
isle of Portland the Portland limestones lie above a clay
base and consequently the area is unstable. There are frequent
landslips and particularly on the northern side Porltand is
slowly crumbling into the sea. At some stage in its past (probably
over 2 million years ago) there were active stream caves on
the island and one remnant system is Blacknor Hole. Since
the system became fossilised and the cliff line has eroded
tectonic (earth movement) rifts have riven the system creaingd
interesting obstacles and scary boulder chokes. Blacknor Hole
was discovered by helicopter! Photographs of the cliffs of
north Portland had been commissioned by Hardye's School Cadet
Force to examine possible climbing routes and a large hole
was noticed on the cliff face below Blacknor fort. Subsequent
investigation by abseiling proved the hole to be a cave entrance
and led to exploration of this extensive system now known
to be linked to Sandy Hole. Sadly access to Blacknor Hole
is prevented at the time of writing (2008) as the landowner
took exception to cavers abseiling over the cliff from the
footpath in front of his land. It is not recommended to explore
the cave from Sandy Hole. The trip would be strenous, route
finding difficult and damage to the rare formations very likely.
Those who wish to know more about caving on Portland may be
able to obtain a copy of The Caves of the Isle of Portland
from the Wessex
Cave Club who published it in 1996.
Blacknor Hole
View along the North-west side of Portland Bill halfway
down the cliff looking south |
Above Blacknor Hole with Weymouth and Chesil Beach
in the distance |
Phil Candy preparing to rig the abseil down to the
entrance |
Phil on the way over the edge |
Phil inside the entrance |
Tony Boycott arrives |
Brian Johnson appearing |
'H' in the vadose tunnel leading away from then entrance
(Ariel Tunnel) |
'H' again (he can seen on the back cover of the BEC's
report on St. Cuthbert's Swallet) |
More of 'H |
Local resident |
Somewhere around Piccadilly |
Grand Canyon |
Crossing the Grand Canyon |
The Grand Canyon is a tectonic rift that's 'cracked
open' the fossil streamway |
Formations in the Grand Canyon |
In the choke |
In the choke |
Emerging from the choke |
Constriction |
Typical Portland formations |
Nick Poole avoids the stal |
Jim Durston in the darkness |
Bedding crawl |
Formations |
In the vadose canyon |
The vadose canyon |
Walking passage - making the most of it. |
Approaching Brownsea Island |
Brownsea Island - beyond here is the awkward and loose
route to Sandy Hole |
Brownsea Island chamber and the fossil sump - choked. |
Vortex Chamber |
Vortex Chamber |
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Sandy Hole
Originally a dig by WCC it was successfully
entered in 1971 by members of the newly formed Dorset Caving
Group and a team from Hadye's School. It is astonishingly
long but unfortunately passage height is rarely more than
a metre if that and the downstream section from the entrance
consists of something like a kilometre of low crawling. It
is unclear from the cave guide to the area as to whether the
passage has been explored to its limits. Upstream a series
of crawls connect by a very devious route to the far reaches
of Blacknor Hole. A reverse trip through the system is not
recommended not least for the damage it would do the formations
in Blacknor. Sandy has two entrances - both are now tricky.
Sharbutts Quarry just below the main cliff top contains a
narrow rift that drops into Sandy Hole via an awkward squeeze
whilst the main entrance is part way down the cliff and as
can be seen from my photos the climb in has changed from an
easy scramble to a VD climb.
Looking down to the end of the Bill from above Sharbutts
Quarry |
Stalagmite on the walls of the quarry - a popular site
with rock climbers. |
Ammonite in the sea cliff |
The entrance 20 years ago |
Michael Glanvill sitting in the entrance |
The climb into the entrance in May 2001 |
Ken Passant makes it in |
The view out |
Brian Johnson crouches in the entrance |
Prize Day Passage |
Near the Inkwell |
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 Gold
and Silver Passage |
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Walditch Cave
I have only visited this system once, taken there by Nick
Poole and his sister with Chris Proctor who surveyed it. The
cave is on a hill outside Bridport in Jurassic limestone and
appears to be phreatic remnant. Most of it is walking sized
apart from a choke that needs to be passed and it ends in
a rather loose looking choke. These may be the only photos
of the cave in existence unless somebody out there knows differently!
The sea cliffs of Purbeck may yield caves to a determined
search. Certainly near Worth Matravers a small spring resurgence
part way down the cliff has left a prominent stalagmite flow
suggesting there may be underground drainage in the area.
There are a number of underground features but these are stone
mines and these can be viewed at Winspit, Dancing Ledge and
Tilly Whim. Many now have grilled entrances to protect the
bat populations.
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