If you wish to log this Cache, please find Lancaster Hole, Top
Sink, and County Pot; then using your GPSr measure the Distance and
Bearing of Lancaster Hole to Top Sink, and Top Sink to County Pot
and work out the area of land in Square Meters between all 3
points.
View Ratings for GCP807
To claim this cache all you need to do is take a picture of
yourself and GPS or just GPS if you are alone, next to one of the
many cave entrances. Now don’t cheat as I know them all in great
depth as this is my weekend stomping ground.
The coordinates N54° 13.064, W002° 30.629 are actually in a
geological feature called Ease Gill, a Gill in the UK refers to
a stream but at this location it is usually a dried up river
(Except at time of sever flood) Ease Gill caverns run under this
old stream bed as the water now sinks higher up the valley, on a
Gritstone / Limestone boundary.
The Caves under and around Ease Gill on the
Cumbria/Lancashire/North Yorkshire border of the UK form the
longest and most complex system in Britain. The system extends
beneath Casterton, Leck and Ireby Fells around the western and
southern flanks of Gregareth Hill, with around 72Km of passages.
The caves are formed in the Carboniferous (Dinantian) Great Scar
Limestone.They contain a wide range of passage types, sediments and
speleothems.
The Ease Gill Cave System extends beneath Casterton, Leck and
Ireby Fells around the western and southern flanks of Gregareth
Hill. The caves are formed in the Carboniferous (Dinantian) Great
Scar Limestone.They contain a wide range of passage types,
sediments and speleothems which give an excellent record of karstic
evolution and associated surface development through the
Pleistocene. The text below is a summary of material provided by
English Nature as the system is a SSSI. and of national geological
importance.
The cave systems described all lie within the catchment of Leck
Beck Head resurgence and contain over 80km of known cave passage.
They can be divided up into three sectors. The Ease Gill Caverns
contains about 60 km of passages mainly under Casterton Fell and
linked below Ease Gil to Link and Pippikin Pots. The caves of the
central part of Leck Fell include Gavel Pot and Lost John's Cave
and have about 12 km of passage with a flooded connection to
Pippikin, giving a total length of at least 72 km. The caves of the
southern part of Leck Fell form another as yet unconnected system
which drains to the Leck Fell caves and is 12 km long.
The Dinantian Great Scar Limestone is about 200 thick with
numerous shale bands up to 2 m thick and dips gently to the
north-west. The limestone and hence the caves are limited to the
west by the Dent Fault. Here the limestone beds are buckled and
faulted against Silurian greywackes to the west in a disturbed zone
up to 200 m wide. The development of Bull Pot of the Witches is
especially controlled by these features. To the south-west the
limestone is cleanly faulted against younger beds but this is
obscured by thick layers of glacial drift. The limestone outcrop is
broken up by many minor faults and major sets of joints running N-S
ad NW-SW. There is also shallow synclines plunging down dip on
Casterton and Leck Fells. These have introduced local controls on
cave development. The shale beds in the limestone have controlled
the level of many of the horizontal passages, while the joints and
faults have controlled the location of pitches. Much of the karst
surface topography has been obscured by thick layers of glacial
till.
The caves systems all derive their surface water from streams
which originate on the upper slopes of Gregareth and Crag Hill.
These streams all sink close to the Limestone boundary with the
Yoredale facies above. The main surface feature is the normally dry
Ease Gill Beck. In dry weather the water sinks upstream of Top Sink
at the Limestone-shale boundary and the valley is dry all the way
to Leck Beck Head. In flood the water flows down the Beck and sinks
at a series of sinks from Top Sink onwards. Leck Beck Head lies
just east of the Dent Fault and is the resurgence for all the caves
between Aygill Caverns to the north and Ireby Fell Cavern to the
south-east. Ease Gill Beck and hence the cave system can respond
rapidly to flood with a flood pulse 0.5 m high having been seen
making its way down the beck after heavy rain. However the floods
also soon subside once the rain ceases.
Ease Gill Caverns is a large cave system containing many types
of passage morphology. The caves are accessible through over a
dozen entrances mainly located in Ease Gill, except for four which
are located on the fells to the north and south. The main feature
of the cave system is the abandoned phreatic trunk passage running
east-west under Casterton Fell.It starts in Top Sink and heads west
to form a complex of old passages in Lancaster Hole. Here it is
joined by similar large old passages from Bull Pot of the Witches.
it then turns south to end in sediment choked passages heading
towards Leck Beck Head.
Almost directly below the high level passages is a fine vadose
canyon, Lancaster Hole Main Drain, 2-5 m wide and up to 30 m high.
Parts of the Main Drain have cut down from the upper level passages
while other sections have bedding plane roofs. There is extensive
undercutting along numerous shale bands with collapse in some
sections from the passages above. The passage ends under Lancaster
Hole in a high rift containing the terminal sump pool. This drains
into a large phreatic conduit 30 m below water level and heading
straight towards Leck Beck Head.
Much of the rest of the system consists of active vadose
streamways draining down dip from Ease Gill Beck, including Top
Sink, Boundary Pot, Borehole, Pool Sink and County Pot. Most of
these inlets descend about 50 m to reach the main drain and are
complicated by captures and re-routings into pre-existing passages.
These passages predate Ease Gill Beck itself as they all have
upstream continuations on the opposite south bank eg County
Caves.
Cow Pot is the only major sink on the shale boundary on
Casterton Fell. The stream descends an open shaft and meanders
along washed out shale bed to a 45 m pitch from the roof of Fall
Pot into Lancaster Hole. The entrance to the latter is close by and
consists of a 35 m shaft into the high level passages.
To the south side of Ease Gill Beck are other entrances to the
system, which consist of another set of high and low level passages
interconnected via shafts. Two entrances high on the fell Pippikin
Pot and Bye George Pot lead down through constricted immature
passages to phreatic trunk routes similar in appearance and level
to those in Lancaster Hole.
Link Pot on the south side of Ease Gill Beck gives easier access
to the old phreatic trunk passages via a 15 m pitch into a large
tunnel beneath the normally dry stream bed. All these passages are
linked to Lancaster Hole via phreatic passages running
north-westwards beneath Ease Gill. The stream passage from Link Pot
and that from Pippikin Pot unite and flow into a flooded passage
and descends a flooded rift to join the phreatic tunnel from Lost
John's and Gavel Pot over 20 m below resurgence level.
Leck Beck Head is the end of a phreatic lift with large
submerged passages from Ease Gill Caverns and the Leck Fell caves
uniting more than 30 m below Witches Cave, the overflow resurgence.
This is only active in times of flood.
To the northern end of the system Bull Pot of the Witches
contains a complex series of old high-level passages. They largely
follow shale beds along the access of folds within the Dent Fault
disturbance zone. The water from the surface pot drains via a
vadose streamway into phreatic loop heading up dip to the high
level passages in Lancaster Hole.