Geology in the Limb Valley

 

An exposure of the Brown Edge Flags

Being essentially reliant on public transport and willingly admitting that I have never really enjoyed strenuous walks up steep hills, which I first encountered when mapping the geology around Borrowdale in the English Lake District and having to ascend 1000 feet for the first 2 weeks of my project, I don’t often get to see tors in the Peak District National Park - as would hardened walkers who frequent the high moors and are familiar with Kinder Scout and Derwent Edge. 

 

Lady Canning's Plantation

 

I was therefore particularly interested to see the Ox Stones, after the disappointment of not finding the Brown Edge Quarries during my exploration of the Rough Rock in Ringinglow. For the next leg of my walk, I set off through Lady Canning’s Plantation on the way to the Limb Valley, where I hoped to find two Local Geological Sites (LGS) that are listed on the Sheffield Area Geology Trust (SAGT) website. 

 

Local Geological Sites in the Limb Valley

 

The Limb Brook rises at the junction of the Redmires Flags and the underlying mudstones of the Marsden Formation, near to the Ringinglow Road and flows eastwards across the Chatsworth Grit, which underlies Lady Canning’s Wood, before passing under Sheephill Road and continuing across farmland, where the Ringinglow Coal and the Marsden Formation form the bedrock. 

 

The geology along the Limb Valley

 

From Sheephill Road the public footpath runs alongside the brook and, before l had walked very far, I encountered an area of very boggy ground that is fed by a spring and the vegetation is dominated by reeds and sedges. 

 

Boggy land with reeds and sedges

A little further down the path, I noticed the ruined Barberfields Copperas Works, which produced iron sulphate from the pyrite that was a biproduct of the mining of the Ringinglow Coal. It had uses in dyes and inks and for leather tanning but, according to the article about Ringinglow’s industrial history in the Ranmoor Society Notes, the works had become disused by the 1850’s . 

 

The ruins of the Barberfields Copperas Works

 

From this point onwards, I followed Limb Brook for a few hundred metres through woodland but could not see any rock exposures in its banks and, with the Peak & Northern Footpath Society (PNFS) signpost providing my only point of reference, the valley steepened very suddenly and any hopes of seeing any rock exposures in the banks of the Limb Brook soon disappeared. 

 

Views from the public footpath alongside the Limb Brook

 

Continuing down the footpath on the north side of Limb Brook, which I followed in the opposite direction from Whirlow on the previous occasion that I had visited the Limb Valley, I saw no signs of any rock outcrop but the steep slopes above me, as marked on the British Geological Survey map, are formed by the Rossendale Formation and the overlying Rough Rock. 

 

Views from the public footpath further down the Limb Valley

 

Further relying on taking photographs of more PNFS signposts to help me to pinpoint the location of the various photos that I took to illustrate this Language of Stone Blog post, Signpost 475 confirmed that I had reached the path that would take me the LGS where the strata above the Ringinglow Coal have been recorded in the bank of the Limb Brook. 

 

The location of the exposure of strata above the Ringinglow Coal

 

The geological memoir describes states that the Ringinglow Coal in this area is overlain by a group of very silty and sandy shales with sandy beds, called the 'Brown Edge Flags’, which varies throughout the district covered by the Sheet 100 geological map that it accompanies. 

 

A view of some of the strata above the Ringinglow Coal

 

From the north side of the bridge across which the public footpath to Whirlowbrook Hall leads, I could see strata that look liked mudstone and siltstone on the opposite bank of the brook, which were visible to varying degrees beneath the vegetation. 

 

Boulders providing stepping stones to the south bank of the brook

 

At the time, the water levels were quite low and, making my westward along the north side of the brook, I found places where I could cross over to the south side, using exposed boulders in the streambed as stepping stones. 

 

Rock exposures on the south side of Limb Brook

 

I soon found a few small exposures of distinctly iron stained thinly bedded sandstone that overlies siltstone and mudstone, which I presume to be the Brown Edge Flags. While taking care not to lose my footing on the slippery ground along the stream bank, I looked for a suitable place to obtain a specimen with my Estwing hammer, before retracing my steps to the public footpath. 

 

An exposure of the Brown Edge Flags

 

The specimen of fine grained sandstone that I obtained is grey in colour, with pronounced orange iron staining where exposed on a bedding plane or joint. On fresh surfaces, I can see very thin beds of approximately 5 mm thick, which show graded bedding and differential weathering and white muscovite mica flakes scattered throughout the body of the sandstone.

 

A specimen of the Brown Edge Flags

 

The Ox Stones

 

A view of the first tors encountered at the Ox Stones

When exploring the Rough Rock in Ringinglow, I was unable to find the old quarry faces at the Brown Edge Quarries which, I have subsequently learned from friends in the Sheffield U3A Geology Group, are not easy to find. On a field trip with Peter Kennett, in whose publication the Geology of the Porter Valley I learned about this site, they approached from a completely different route to the one I attempted. 

 

A view of the Ox Stones from the footpath to the Brown Edge Quarries

 

After retuning to the public footpath back to Ringinglow Road, I got my first glimpse of the Ox Stones, a group of tors to the west of Lady Canning’s Plantation, which stand proud of the surrounding heather and blanket bog covered moorland formed on the Chatsworth Grit bedrock. 

 

The geology of the area around the Ox Stones

 

Crossing over Ringinglow Road and following the well maintained public byway for a short distance, the path to the Ox Stones is less well maintained and subject to erosion by water run off and, to mitigate this in places where it presumably gets quite boggy, it is paved with riven flagstones and on one of these I noted some spectacular ripple marks. 

 

Flagstones with ripples

 

Arriving at the first tor, the first thing that I noticed was that the thinly bedded Chatsworth Grit here displays steep cross-bedding in its lower part, which I would consider to be quite typical of most coarse to medium grained Upper Carboniferous sandstones that I have seen, but the upper part has extremely shallow cross-bedding. 

 

A view of the pattern of bedding in the lower and upper parts of a tor

 

Looking at the relationship between the two parts on my high resolution photos, instead of a planar surface, which typically separates beds of sediment, the upper surface of the lower part seems to be rippled, with these original sedimentary structures being filled with later sediment instead of them being eroded away. 

 

Variation in the bedding characteristics of the lower and upper parts

 

Moving on to the second tor, this difference between the lower and upper part is seen again, with the latter beds being essentially horizontal and the cross-bedding seen is again at a very shallow angle. Differential weathering has highlighted the individual beds in the tors, but it is also noticeable that the lowest exposures of the gritstone are very massive. 

 

Massive beds exposed in the lowermost part of the second tor

I have seen many outcrops of the Chatsworth Grit and have noted considerable variation in bed thickness, grain size and the scale of cross-bedding which, to my understanding, reflect variations of the flow regime – with large underwater dunes at the base and thinner planar beds at the top reflecting a faster flow of the river.

 

Blocks of gritstone scattered around the moorland

 

Looking around me, I could see several large blocks of gritstone scattered around the moorland, which are large enough to be marked on the Ordnance Survey map. I didn’t spend any time investigating these, but instead headed towards another group of less well developed tors that lie a short distance further to the west.

 

Coarse gritty sand exposed in a path at the Ox Stones

 

Although the principal rock formation that forms the spectacular gritstone edges, the Chatsworth Grit, is much harder and more durable than the mudstones and shales of the Marsden Formation that occur above and below, it contains a high proportion of feldspar and clay minerals. 

 

Approaching the western part of the Ox Stones

When broken down into much smaller pieces than seen on the escarpments and tors, the weathering of these minerals leaves the Chatsworth Grit very friable and its rapid erosion accounts for the thick layers of coarse sandy soil that I had seen exposed on paths when walking along Curbar Edge and exploring Blacka Moor Nature Reserve and here at the Ox Stones. 

Tors at the western part of the Ox Stones

I have not seen much information about how these and other tors – especially those seen by hardened walkers on the high moors of Kinderscout and Derwent Edge - were formed, but an article by Professor Matthew Blackett suggests that they most likely formed when the region had a tropical climate and the gritstone was subjected to deep weathering processes and with widening of joints in the bedrock, which have since become exposed as the weathered material above has been eroded away. 

 

At the western part of the Ox Stones

 

An alternative theory is that they were produced in periglacial environments with freeze-thaw activity shattering the exposed bedrock material and erosive processes removing the material; however, the only other tors that I have seen are the Eagle Stone on Baslow Edge, the Cork Stone at Stanton Moor and a prominent example on Higger Tor, none of which I have studied closely and I am therefore unable to comment further. 

 

Trough cross-bedding

I only spent 15 minutes exploring the Ox Stones, but there are a wide variety of interesting sedimentary structures here, including what I think must be trough cross-bedding, and I would be very interested to visit the site again with an experienced sedimentary petrologist. 

 

Pebble beds in the Chatsworth Grit

 

Of paerticular interest were some very fine examples of very coarse grained beds, which contain rounded pebbles of white quartz, which are up to 15 mm in diameter. They were formed at the base of the large subaqueous dunes formed in a large river that flowed into a vast Namurian delta, with the source being granite in the Caledonian Mountains that existed far to the north-east.

 

A detail of a pebble bed (22 mm diameter coin)

 

The collecting of rock specimens from spectacular rock formations as The Ox Stones is considered by the geological fraternity to be completely unacceptable; however, numerous small pieces of Chatsworth Grit were lying around the eroded paths. Although many of these, as I have previously discovered, can be quite ‘rotten’ and easily crumble, I did manage to obtain a specimen of unweathered rock to add to my growing rock collection. 

 

A specimen of Chatsworth Grit

Exploring the Rough Rock at Ringinglow

 

A specimen of thinly bedded Rough Rock

 

During the Heritage Open Days festival in 2023, I had visited St. Peter’s church in Kirkthorpe, St. Mary’s church in Whitkirk and, to help prepare my friend Catherine for her Sheffield U3A Geology Group field trip, attended a geological tour of Sheffield General Cemetery led by Peter Kennett. 

 

A map from the Geology of the Porter Valley by Peter Kennett

 

A few years earlier, having discovered the Sheffield Round Walk, looking through the Sheffield Area Geology Trust (SAGT) website for ideas for my excursions, I discovered that Peter’s Geology of the Porter Valley walk included the Brown Edge Quarries and Ox Stones as stopping points. 

 

The Ordnance Survey map of Ringinglow

On that occasion, the very infrequent bus from Sheffield to Ringinglow didn’t turn up and, having already had to quickly walk up the Limb Valley, I didn’t have the time or energy to explore these and just walked from Ringinglow down the Porter Valley to Endcliffe Park.

 

The LIDAR map of the Brown Edge Quarries

 

Taking a short break from the Heritage Open Days events, I spent my time looking at various maps – including old and modern Ordnance Survey maps, LIDAR and the Open Street Map – to try and identify the location of the remaining quarry faces at the Brown Edge Quarries, which Peter’s leaflet says are at the west end of the site. 

 

The Brown Edge Quarries on Open Street Map

Alighting from the No. 181 bus, I took a photo of the Grade II Listed Norfolk Arms public house, where the very large quoins and very distinctive triangular first floor window heads are no doubt made from very massive sandstone that is only found locally in the Chatsworth Grit. The walling is composed of smaller but moderately sized blocks of squared sandstone, but I didn’t cross the road to take a closer look. 

 

The Norfolk Arms

 

Continuing west along Ringinglow Road, the terraced houses to either side of Fulwood Lane are built with a massive sandstone that, from a distance, appears to have very similar physical characteristics but the original roofing material, which was probably stone slate, has been replaced with modern interlocking concrete tiles.

 

Terraced Houses on Ringinglow Road

Although I have seen plenty of stone slate roofs that I can reasonably assume to have been quarried from the Rough Rock, I have not yet come across any building that is known to have used this stone for well squared and coursed walling. 

 

A garden wall on Ringinglow Road

 

Looking at the Building Stones Database for England map explorer around Ringinglow, except for the Houndkirk quarry on the Chatsworth Grit, all of the Brown Edge Quarries are located on the Rough Rock, which around Sheffield tends to be thinly bedded and, although some beds produced walling stone, it was best known for producing stone slates for roofing and flagstones for paving. 

 

Old quarries in Ringinglow

 

Continuing along Ringinglow Road, I soon entered the boundary to the Peak District National Park, which is typically marked with a large millstone that may well have been made at the extensive old quarry along Burbage Edge. 

 

A millstone marker to the entrance to the Peak District National Park

 

I continued for another kilometre, noting the general north-easterly dip of the strata of the upper part of the Millstone Grit Group, which underlies the open countryside to the north of the road. Although the LIDAR map shows numerous old bell pits that once worked the Ringinglow Coal at the top of the Chatsworth Grit, I didn’t notice any of these any only stopped to take in the fine view of Sheffield from this point. 

 

A view towards Sheffield

 

Arriving at the public footpath opposite the west end of Lady Canning’s Plantation, I headed north along a rough path that crossed mudstones of the Marsden Formation, sandstone of the Redmires Flags and further mudstones of the Rossendale Formation, which form minor features in the landscape due to their differential weathering. 

 

The public footpath to the Brown Edge Quarries

I carried on until I reached higher ground, which corresponds with an extensive area occupied by the Brown Edge Quarries that is now entirely covered in heather. Having looked at Google Map to see possible routes, I thought it would be easy enough to find a way to the western part of the site where there is an extensive rock face. 

 

A view across the overgrown Brown Edge Quarries

Once on the ground, however, I couldn’t find any obvious path and the one that I eventually took came to an end without any obvious way of continuing westward and, looking at Google Map again in retrospect, I perhaps should have continued north along the path until I got beyond the quarried area and then turned sharply to the west. 

 

A view across the overgrown Brown Edge Quarries

 

I decided not to press on with my search and decided to retrace my steps back to the public footpath via very poorly defined small tracks that may well have been made by sheep. I didn’t see any rock faces but, in one or two places where the soil has eroded away, I obtained samples of thinly bedded fine grained sandstone that has white muscovite mica on the bedding planes.

 

Specimens of thinly bedded Rough Rock

Having made the effort to get here, I was quite disappointed not to find the old quarry faces, but it was not yet 2 o’clock on a nice sunny day so, after taking a couple of photos of a gritstone edge in the distance, which I think must be part of Stanage Edge, I eventually worked my way through the heather until I finally reached the public footpath and headed off to the Ox Stones.

 

A distant view of Stanage Edge seen with a telephoto lens

 

Geology in Sheffield General Cemetery

 

The monument to Mark Firth

When the 2023 field trip itinerary for the Sheffield U3A Geology Group was being planned at the beginning of the year, there were a few gaps and the less experienced members were encouraged to come forward and lead a field trip – one of which was my friend Catherine, who I had been helping with her Bolsterstone Graveyard Project for the last year and had agreed to speak at an event that she had arranged for the Bolsterstone Archaeology & Heritage Group.

 

The General Cemetery - A Geological Trail

 

A list of field trips undertaken by the group since 2007 had been circulated to its members and Catherine had the idea of organising a visit to the Sheffield General Cemetery (SGC), which the group had visited at least twice before I joined the group in 2015. 

 

Rock in the General Cemetery

I assume that these visits were based on the publications: The General Cemetery – A Geological Trail (2001) and Rock in the General Cemetery (2004), which were written by a colleague, Peter Kennett, who I had helped with the Building Stones of Sheffield (1999), when I was the Chairman/principal surveyor for the South Yorkshire RIGS (Regionally Important Geological Sites) Group. 

 

The Stone Spiral

 

Despite my reservations about this being suitable for a field trip, which typically runs from 10:30 am to 15:30 pm and involves a good walk, having already undertaken the Let's Talk About the Stones event at Moorgate Cemetery in Rotherham earlier in the year, I agreed to help Catherine with her preparation for a morning event and I would lead the group around Nether Edge in the afternoon – the recce for which I have already reported on in this Language of Stone Blog. 

 

Meeting at the gatehouse for the 2023 Heritage Open Days event

When researching the 2023 Heritage Open Days events, I noticed that Peter Kennett was due to lead a short walk around the cemetery with two other geologists and I therefore made arrangements with Catherine to attend this event and, after spending two very full days in the past week to visit Heath, St. Peter’s church in Kirkthorpe and St. Mary’s church in Whitkirk, we met up on a rainy afternoon the following Tuesday. 

 

A display panel produced by Peter Kennett

 

Referring to the publications listed above, I had visited SGC a few times and I knew that Peter had been leading walks here for many years and, as a teacher of geology at High Storrs School in Sheffield, I had been aware of his many publications for the Earth Science Teacher’s Association and he started the afternoon by showing us a couple of information boards. 

 

A display panel produced by Peter Kennett

 

I was particularly interested to see the display with samples of the various stones that are have been used for memorials in the cemetery or in the Stone Spiral. When working in the building restoration industry in London, I used Dr. Eric Robinson’s London Illustrated Geological Walks, with black and white photographs, to learn how to identify various building stones and I appreciated the display of granites that I presume is related to his work for the Earth Learning Idea website.

 

Dr. Eric Robinson's London Illustrated Geological Walks

 

Although the 20 minute introduction to geology was no doubt appreciated by Catherine and other attendees, I have to say that I was more interested to hear what Peter had to say about the memorials themselves – partly because I already have extensive experience of building stones, but mainly because the timing of this would be very relevant to our field trip. 

 

An introduction to British geology by Peter Kennett

Moving on to the rear of the gatehouse, we stopped at the large blocks of Swedish Imperial Red granite, the Emerald Pearl variety of Larvikite and Rubislaw granite, which are commonly seen in the plinths and door surrounds of various Victorian buildings in large towns and cities, including Sheffield, we made our way past the restored catacombs before arriving at the Stone Spiral. 

 

The Stone Spiral

 

I remember seeing this shortly after it was installed, when the colours and textures of the sedimentary, igneous and metamorphic rocks could be quite clearly seen, together with the inscriptions that had been cut into them; however, weathering, dirt, moss and algae had taken their toll and when I had last seen them in December 2021, I could barely distinguish very many of the 29 stones in the spiral, which contains 9 different types of stone. 

 

Examining the Stone Spiral

 

Shortly after this, when I first became aware of the £3.8 million 4 year programme of conservation and repair that was coming to an end by the time of my visit with Catherine, I did suggest to staff at SGC that it might be a good idea for the Stone Spiral to be cleaned, but nothing came of this. 

 

 Granite monuments on the main path to Sandford's Walk

 

Retracing our steps to the gatehouse, Peter then led us up the main path towards Sandford’s Walk, where several large and impressive monuments – including those of Eliza West, Abraham Sharman and Charles Wardlow - display several types of granites, but quite surprisingly spend hardly any time looking at them.

 

Headstones laid out on the bank next to the main path

 

Standing back from the group to take photographs, I didn’t hear what Peter had to say about these granites, or the numerous large headstones and crosses, which are laid flat on the bank on the opposite side of the track and are undoubtedly made from the local Brincliffe Edge Rock – the local name for the Greenmoor Rock. 

 

The Joseph Hadfield monument

 

The next stopping point was the Joseph Hadfield monument, which is mainly made with sandstone that has been highly weathered by the effects of frost action, but which also has inscribed panels of white Carrara marble. The latter is also very weathered and, viewed with a hand lens, the saccharoidal texture can clearly be seen. 

 

The Burch monument

 

I only photographed the columnar Burch monument from a distance, which is built with stones that are not mentioned in Peter’s booklet. The monument is surrounded by an iron railing but, from his photo, it looks like another example of Carrara marble, with various horizontal moulded sections and panels that, from my photos, appears to be Peterhead granite.

 

The monument to William Parker

The Grade II Listed monument to William Parker (1837) is quite unusual, being constructed from dolomitic limestone from the Permian Cadeby Formation, which I can recall seeing used for such purposes in the Waller family monument at Hyde Park Cemetery in Doncaster. One of the attendees, who had studied geology, noticed several pairs of circular impressions, which he thought could be U-shaped burrows and, having come across similar structures myself in headstones, I agreed with him. 

 

The monument to William Parker

 

Peter did show us other monuments and the Samuel Worth Chapel, which is built from very coarse grained and pebbly Chatsworth Grit, before we finished at the Grade II Listed monument to Mark Firth, a steel magnate, philanthropist, Master Cutler and Mayor of Sheffield. This is made with grey granite, but again I didn't hear what Peter had to say and I didn’t look closely at it on this occasion. 

 

The monument to Mark Firth