Text Box: Exploring Whitbarrow Limestone 

 


I attended The British Cave Research Association the Cave and Karst Science Field Meeting along with Bill Holden and Pete Standing from the Red Rose. We met up at the hamlet of Millside, off the A590 between Levens and Lindale, southern Lakeland. The field meeting involved a walk of approximately 9km to the Whitbarrow limestone outcrop, to be led by Dr. Phillip Murphy, of the University of Leeds. Most of the outcrop, including extensive pavements, and the closely associated acidic grassland, juniper scrub, heath and woodland, fall within the Whitbarrow SSSI. Part of this is also the Whitbarrow NNR, and a small part of that is also the Whitbarrow Scar LNR. It is not surprising therefore that this whole area is highly regarded by conservationists for its rich mix of largely natural environmental facilities that combine to support an equally rich invertebrate, bird and small mammal community, quite apart from its superb karst features. The hill is prominent from the A590 road with its steep limestone cliffs, laid down in the Carboniferous period 350 million years ago. The main cliff faces are made up of rocks known as Dalton Beds, above which are Urswick Limestones, of which the limestone pavement (here and elsewhere around Morecambe Bay, including Hutton Roof Crags has been formed. The steep cliff of White Scar dominates the view of the south end of the Whitbarrow Plateau, when approaching southern Lakeland from the east. Its lower screes have been extensively removed, adding to the dominance. The Lyth Valley, crossed immediately before this, is famous for growing damsons. Here the valley floor was carved out into deep basins by ice-flows, and these have since been deep-filled with fertile soil. Extensively around Morecambe Bay, shallow basins have been filled in this way with sediment and now form the ‘marshes’ and ‘mosses’ of the area, e. g. Foulshaw Moss, Arnside Moss and Silverdale Moss. However, between the mountains to the north, the ice excavated even deeper basins that now give the area its famous name: The Lake District. We set of at just after 10 am and it was well attended with over 30 people including some well known northern cavers. We visited the various limestone pavements, caves, mine levels and geological, glacial and hydrological features in the area. There was a small charge of £6 (£3 for BCRA members), payable on the day. Attendees were given a copy of a new BCRA Cave Studies Series booklet, Exploring the Limestone Landscapes of the Cumbrian Ring, written by Dr. Murphy, of which this walk comprised one excursion. This has yet to be published so we got a free advanced copy.

The excursion started by walking uphill towards the Whitbarrow escarpment passing through the hamlet of Millside. A lay-by on the left allowed a view of the older, Silurian age Bannisdale Slates rocks that underlie the Carboniferous Limestone. Just after this we turned right up lane marked as Beck Head only passing at the information board which gives details of the geography and history of Witherslack. The road degenerated into an old bridleway traversing round the front of the Whitbarrow escarpment passed several exposures of limestone. A footpath on the left continued uphill and passes the first karst feature of note. This is a fenced off spring with tufa deposits around it. It is not clear why the spring is at this height half way up the scarp slope but the limestone does contain minor faults and shale beds in this area. Eventually the path breaks out through the wood land into more spare vegetation including gorse, brambles, blackthorn and heather. These are plants normally confined to acid soils and would not be expected on limestone uplands. The reason they are here was explained to us by Dr Murphy. The limestone is covered over with loess deposits. This is a wind blown deposit derived from Morecambe Bay area during the last glaciation when the sea level was lower and the area was a pro-glacial desert. In other limestone areas the loess deposits have been transported through the cave systems and very little is left on the surface. The amount surviving on Whitbarrow suggests that underground drainage in this area might not be very well developed.

Further on up the slope is a great view across Whitbarrow with meanders of the River Kent clearly seen below. The plateau here contains scattered erratic boulders from the Borrowdale Volcanic Group dropped here by the Lake District ice cap. Higher up the slope we passed several cairns built from the heavily weathered and shattered limestone. Other karst features in this area are a number of shallow dry valleys and shake-holes. These seem to be associated with faults which cut across the plateau. The dry valleys may have been formed under peri-glacial conditions when the sub surface was frozen hard at the end of the ice age allowing streams to run across the surface of the limestone. It was a cold windy day on top so we sort shelter on an area of limestone pavement and had our lunch.

The highest point of Whitbarrow is Lords Seat and is well worth a visit as it is a spectacular viewpoint with the Lyth valley to the east and a great view of the central Lakes to the north. To the west beyond a fault scarp is the Witherslack valley. From Lords Seat we headed north over limestone outcrops to a wall and turned left at a drystone wall towards Witherslack. The path leads into a dry valley and just after this a small spoil heap is passed. Above the tip is a 27 metre long mine level called Bell Rake. There is a clear iron stained calcite vein above the entrance.

We next headed further down the dry valley to a path junction and stumbled off through woodland in search of Pool Bank Cave. This resurgence cave is also known as Fairies Cave

 

Dip slope of Whitbarrow with meanders of the River Kent beyond.

          

Bell Rake mine level                                                       Entrance to Pool Bank Cave

SD434877. The entrance is a dark slot above the choke of mossy boulders. The sound of running water can be heard inside although none was visible emerging. The entrance leads down a stalagmite slope to a sump pool. In 1979 the cave was extended by the Cave Diving Group to a length of 37m and has since been pushed up an awkward climb to a second sump which continues to be explored. After heavy rainfall a lot of water comes out and has cut a deep short gorge below the entrance. After exploring the cave we continued down hill through woodland and past Witherslack Hall School out into the Witherslack valley between Whitbarrow and Yewbarrow. This is a wide flat glaciated valley which has been overdeepened by glaciation and now filled in with peat and other deposits. We followed the road for about 600 metres and turned left on the public bridleway to Beck Head. Here, as the name implies is a resurgence cave. The large stream emerges from a small cliff and it the only one in northern England to be signposted from a main road. The cave has been explored by cave divers including Phil Murphy who dug through underwater chokes for 100 metres to a vertical rift that was too tight to get into.. A later dye trace showed that the water does not come from the Whitbarrow area but from a sink near Whitbarrow Hall to the north. The hole near the person in the yellow jacket in the photo is only a field drain. Just down the road from here an exposure of green rock tells us that we had left the limestone and that the cave is at the base of it on the unconformity. From here it was a short wall back to the car.

   Beck Head Rising

Andy Hall

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