King of the Castle
Castle Crag is the smallest hill included in Alfred Wainwright's Pictorial Guide to the Lakeland Fells, the only Wainwright below 1,000 ft.
Castle Crag has an impressive appearance, a rugged height apparently blocking the valley of Borrowdale, which is squeezed between Castle Crag and Grange Fell, its neighbor on the other side.
High Spy, the parent fell, forms part of the north-south ridge between Borrowdale and the Newlands Valley.
Geology of the lake District
In the Lake District, 500 million years of geological processes have produced a physical landscape of mountains and lakes of great scenic beauty.
Slate developed from sediments in oceans and seas, volcanoes erupted, limestone was formed by the deposition of dead crustaceans and sandstone was created in desert conditions. Various minerals were also formed in joints and faults in the bedrock.
The layers of rock formed were shifted and sculpted - first through different stages of folding and uplifting and then by the actions of glaciers and meltwater.
As a result the topography of the Lake District includes smooth U-shaped valleys and steep and sharp ridges, England’s highest mountain and deepest and longest lakes.
Skiddaw Group
The Skiddaw Group are the oldest rocks in the Lake District. They were formed as black muds and sands settling on the seabed about 500 million years ago. They have since been raised up and crumpled and squeezed. These rocks are found mainly in the north of the National Park and the mountains they form are mostly smooth, though many streams have cut deep gorges.
Borrowdale Volcanic Group
Found in the central Lake District, the 'Borrowdale Volcanics' are very hard lavas and ashes formed in catastrophic eruptions about 450 million years ago. They make up the highest and craggiest mountains: Scafell, Helvellyn and the Langdale Pikes. These peaks are not the remains of the original volcanoes - they are the harder volcanic rocks that have withstood erosion.
Windermere Group
Sedimentary mudstones, sandstones, siltstones and some limestone formed in the sea about 420 million years ago. These were later folded and faulted, pushed up, and eroded down to their present levels former the gentler scenery of southern Lakeland.
Granite
Huge masses of granite formed about 400 million years ago deep below the Lake District. Erosion has revealed outcrops in Eskdale, Ennerdale and at Shap.
Limestone
320 million years ago a tropical sea covered the Lake District. The shell remains of incredible numbers of small animals formed limestone which is visible at Whitbarrow Scar and Scout Scar in the south of the National Park.
Why are there so many lakes?
The Lake District has over fourteen lakes and tarns. The Lake District’s volcanic rock does not allow water to seep away. The high rainfall, combined with the extra deep glacial valleys, means that the valleys are able to store large volumes of water.
Quarrying
Many Lake District rocks have been quarried, mostly for use in the construction industry.
There are many miles of drystone walls and numerous village buildings made of local stone which came from small Global quarries.
The most important rock quarried in the Lake District is slate taken from the Borrowdale volcanic group. The most famous quarries were around Honister Pass.
Various types of Granite were quarried for use as kerb stones and stone setts. Granite was quarried near Ravenglass, in Eskdale, at Threlkeld and at Shap.
Mines in the Lake District were created to exploit mineral ores which formed as ‘veins’.These mineral veins filled cracks (joints and faults) in between the surrounding rock quarried when mineral-laden groundwater cooled and depressurised as it progressively circulated through the bedrock. Veins are very unpredictable in their thickness and mineral content and, as a result, mining them was always a financial risk. Some of the more famous mines were Greenside lead and silver mine, Borrowdale graphite mines and Coniston copper mines.The slopes of Castle Crag are extensively quarried with pits and levels on the northern and south eastern flanks. The summit has also been extensively worked.
The High Hows Quarry later achieved fame as the home of Millican Dalton, the eccentric and self-styled "Professor of Adventure". The caves here at Castle Crag formed his summer home from the 1920s until shortly before his death in 1947.
The Derwentwater fault
The Derwentwater fault runs along the valley of Broadslack Gill, the higher ground to the north west being mainly composed of the Birker Fell Formation. These are plagioclase-phyric andesite lavas and subordinate sills. By contrast Castle Crag shows a mixture of siltstone, sandstone, conglomerate and tuff with frequent andesite sills.
Summit and View
The summit area is believed to have been an ancient hill fort, although the western section has been sliced away by quarrying. It can only be gained by means of a sloping crack to the south. The very highest point is a rock outcrop about eight feet high and twelve feet across. Atop this is a well constructed circular cairn of slate. A memorial to Borrowdale men killed in World War I is affixed to the outcrop.
To get credit for this cache please send us an email with answers to the following questions:
1. As you Climb up the zigzags through the spoil to the summit quarry what kind of rock do you see ?
2. Describe the color of the rock.
3. How was this rock developed?
4. Bear right to the trees and follow the path up the grass slope to the summit. Take a look at the valley do you think it is V-shaped or U-shaped? How do you think it was formed?
It would be nice if you take a picture of Castle Crag and upload with your log.
You can log your find as soon as you send me the answers. I will contact you if there is a problem.
The above information was compiled from the following sources:
- Wikipedia, the free encyclopedia
- Lake District National Park