At 530 m elevation in the North Pennines, Pike Law is an upland moorland well known for centuries of lead mining. The photo shows a rushy moorland now used for sheep grazing and grouse shooting, with Cross fell, at 893 m visible on the skyline.

Although the bedrock is of Carboniferous age, it is covered in more recent glacial deposits, such as the drumlins in the picture below. Composed of till, or boulder clay, they form large rolling ovoid features in the landscape.

We explored the West End and flask hushes in an area widely scarred by these huge extractive fissures. The West End hush shown below is 300m from East to West and 170m from North to South. This hush has a SSSI status for its fine exposure of mineralized Great Limestone in which many features both of the original limestone, and its subsequent alteration are clearly displayed. The supergene mineralisation (processes or enrichment that occur relatively near the surface) can be seen here, both in the exposed rock face and the abundant debris at its foot.

The dark grey crystalline mineral shown below is Galena. It the natural mineral form of lead(II) sulfide (PbS), the most important ore of lead.

Fluorite, calcium fluoride, CaF₂ was also mined here but regarded as a waste product. It is found in numerous spoil heaps, occurring as purple or yellow crystals.

Potamogeton polygonifolius or bog pondweed, is an aquatic plant. It is found in shallow, nutrient-poor, usually acid standing or running water, bogs, fens and occasionally ditches. It seems to be thriving in the wet hush bottom.

The Flask Hushes have limestone outcrops forming their walls. The west end of these hushes show some structure with the top of the limestone visibly dipping at 30 degrees to the SW, weathering to a brown colour, with open joints, probably associated with the fault/ vein running along the hush,

Leat dams and reservoirs are a feature at the head of the hushes. Probably the dams were formed from boulder clay and the reservoir water used to flush minerals out of the veins and spoil downstream.

The area has been extensively worked by shaft and Adit over the centuries. In the bottom of the east end of the hush there are traces of an Adit with large boulders tumbled over its entrance.

The Great Limestone forms the Southern wall of the hush, looking from the North, it appears dip gently to the West. It is being overlain by flaggy sandstones and mudstones.

One of the mysterious features of the area are these boulder lines found at the head of outwash fans. Composed of limestone and sandstone rocks, they line one side of the ditch in long swathes. There origin is obscure but seem to have been deposited by mining and outwash processes.

The Great Limestone is noted for its fossils. Dibunophyllum bipartitum is shown in both photographs below. It is a solitary rugose coral of the Carboniferous. The picture below gives a cross-sectional view with the septa visible.

A longitudinal view reveals coral to be about 10cm long.

Waxcaps are a sign of old cropped unimproved grassland. A Ballerina waxcap (Porpolomopsis calyptriformis) showing its skirts off. They are thought to have a mutualistic relationship with mosses.

Lichens like the conditions up on this moorland. This shining brown Cetraria aculeata is one of the many types.

Reference: https://designatedsites.naturalengland.org.uk/PDFsForWeb/Citation/1003630.pdf

http://northpennines.wp-sites.durham.gov.uk/wp-content/uploads/sites/37/2018/11/Pike-Law-geology-report-by-Colin-Fowler.pdf

https://www.bgs.ac.uk/discoveringGeology/time/Fossilfocus/coral.html

Roseberry topping is an erosional outlier of the Ravenscar Group on the western edge of the Cleveland escarpment. The area was extensively glaciated and the stratigraphy dips towards the South- Southeast.

The photograph above shows Newton Wood- mostly of Sessile Oak , Ash and Hazel of some age and probably planted on ancient woodland soils. It is noted for its springtime native bluebell and Stitchwort woodland floor plants. It occupies the glacial till overlying the Redcar mudstone formation  described by the BGS as grey fossiliferous, fissile mudstones and siltstones with subordinate thin beds of shelly limestone in lower part, and fine-grained carbonate-cemented sandstone in upper part.

On climbing up through a woodland path we came across bedrock of the Staithes formation shown below. Described as silty sandstone, more or less argillaceous (clay), typically intensely bioturbated and/or showing bedding structures of many types. Bioturbation is defined as the reworking of soils and sediments by animals or plants. These include burrowing, ingestion and defecation of sediment grains. These activities have a profound effect on the environment and are thought to be a primary driver of biodiversity.

Out of the woodland we emerged onto a bench in the landscape formed by the Cleveland Ironstone formation. This formation of mudstone, silty, argillaceous siltstone and silty sandstone with seams of sideritic and berthierine-ooidal ironstone, occurs typically at the tops of small scale sedimentary cycles. The land here was quite disturbed and hummocky, vegetated with rough pasture and gorse bushes. The rich red colouring  from rabbit burrows shows the presence of red Ochre. Red ochre, Fe₂O ₃, takes its reddish colour from the mineral hematite, which is an anhydrous iron oxide.

Although probably mined since prehistoric times Roseberry ironstone mine was commercially founded in the 1870’s and continued until the 1920’s. Underneath Roseberry Topping is a labyrinth of mine workings, some think responsible for the slope collapse visible at the peak. We passed an ancient European Larch tree, a deciduous conifer looked as if it have been growing here for centuries, part of a larger plantation that once flourished here. Larch’s presence in the UK was first mentioned in 1629 and itt soon became a popular plantation tree.

The track of a mine tramway still exists, stones along the surface showing evidence of many fossils like this one – possibly the bivalve Venericor.

Lying above the Ironstone formation is the Whitby Mudstone formation of medium and dark grey fossiliferous mudstone and siltstone, laminated and bituminous in part, with thin siltstone or silty mudstone beds and rare fine-grained calcareous sandstone beds; dense, smooth clayey limestone nodules very common at some horizons.  Beds of Grey and Alum shale occur showing up on the grey grey crumbly slopes covered in distinctive brown bracken. Bracken likes dry, slightly acid soils under 450 metres.

Jet is a type of lignite, a precursor to coal, and is a gemstone. It is derived from wood that has changed under extreme pressure and thin beds occur in the Whitby Formation. Spoil heaps from a Jet mine below the Topping supported different types of plants more typical of Heathland- Heather, bilberry, rich mosses and many lichens such as this cladonia diversa.

Moorland fungi such as the Moor Club pictured below forms relationships with Heather, thriving amongst the lichen (Cladonia furcata?)

The Saltwick Formation forms the craggy peak and most of the Cleveland escarpment tops. Consisting of grey mudstone, yellow-grey siltstone and yellow, fine- to coarse-grained sandstone, the sandstones commonly display sharply erosional bases, and channel-fill bedforms. Plant remains and plant rootlets are common in some beds.

The picture below shows thick channel sandstone with some cross-bedding. Although sauropod and stegosaurus footprints have been found in this Middle Jurassic formation, none were visible here.

The view from the top shows the deltaic beds of the Saltwick formation snaking across the Cleveland hills into the mist.

The Cleveland Dyke is an igneous intrusion which extends from Galloway in southern Scotland through Cumbria and County Durham in northern England to the North York Moors. The dyke is associated with volcanism which took place in the Isle of Mull igneous centre in western Scotland during the early Palaeogene Period. During a time of regional crustal tension associated with the opening of the north Atlantic Ocean,  innumerable dykes were emplaced across the region. It has been extensively quarried along the Langbaugh ridge at Cliff Rigg for roadstone and setts destined for Leeds. Half a mile in length, quarrying began in 1869 and production stopped in 1918 leaving a huge gully in the landscape.

The treeless gap marks out the course of the dyke as it makes its way to the North Sea.

This photo shows the elevation of the ridge formed by the Dyke with the dramatic Cleveland hills forming the backdrop.

References

Yorkshire Rocks and Landscape: A Field Guide (Rocks & Landscape)  Apr 1994
by Yorkshire Geological Society (Author), Colin Scrutton (Editor)

BGS -Lexicon of named units  BGS