Some
of Dorset's most 'unique' caves are located on Portland.
Only a brief drive away from the caving haven of Mendip -- the island
is an
excellent base for the beginner to experienced caver especially if
they are also interested in other adventure activities such as snorkelling, trekking,
diving, rock climbing, cycling or surfing.
This limestone island of 4 miles and only 1 1/2 mile wide with a limestone
layer some 70 feet deep, offers three distinct forms of caves for the
underground explorer -some with unusual features- varying in sporting
and scientific interest.
Portland boasts a number of dry
caves and sea caves.
Cliff entrance to Sandy
Hole Cave
Dry Caves:
Portland's oldest caves are the Water worn caves with near horizontal
bedding ~ being the only resemblance to the Yorkshire Dales caves. Yet, even
though large rift or mass-movement caves are fairly unusual in Britain,
these appear to form the largest category on Portland, mainly following the
massive jointing. Some of Portland's cave systems are in excess of 1.5
miles.
Portland Sea Caves
Sea Caves: Numerous sea caves girdle
Portland Bill where the limestone dips to sea level. Some of these can
be explored by land while others can only be reached by sea. These are
typically large joint or bedding-plane chambers, some of them utilising
rifts.
Notes and Warnings: While quarrying has
claimed its toll on a few of the island's cave sites including some of
the most beautiful ones, those surviving are waiting to be explored and
have attracted the attention of nation-wide caving clubs and groups.
Please respect ongoing digs and underground formations. Consult local
tide tables before venturing into any sea-caves as exits and entries may
be difficult.
The
Wessex
Cave Club
Reading up on Portland
Caves: The Caves of the Isle of
Portland, 104 pp, Mike O'Conner and Nigel Graham, Wessex Cave Club
Occasional Publications Series 3 No.3, 1996, ISBN 0950043346. This
publication and others can be obtained through the
The Wessex
Cave Club link.
Portland Geology:
An excellent source of information to the caves and geology
of Portland with a regional breakdown, charts and formation information
can be found at the web site of
Southampton University
.
