Saturday, 21 July 2018

A Trip to the Magpie Mine

A general view of the Magpie Mine

After a couple of busy days in February this year, giving a talk to Aston-cum-Aughton History Group and leading the Sheffield U3A Geology Group around Sheffield city centre to look at its building stones, the cold weather and snow put paid to exploring for the next month. 

The Agent's House and Smithy

On a bright but very cold day in March, with a biting wind, the group reconvened at the Magpie Mine in the Peak District National Park, which was the last working lead mine in the Derbyshire ore field until it closed in 1951. 

At the start of the tour

All of the shafts and entrances to the mines are capped and there is no entry to the mine and the main attraction of the site is to wander around the site to appreciate the remains of the engine house, chimneys, miscellaneous buildings and the winding gear, which make it probably the best preserved example of a 19th century lead mine in the UK, for which it merits ancient Scheduled Monument status. 

The winding gear

With no access available to the various buildings, the group was led around the site by Keith Gregory of the Peak District Mines Historical Society, who provided an explanation of its history and told us various tales about of bitter disputes and fights resulting in the “murder” of three miners, and a Widows’ Curse that is said to remain to this day. 

An old winch

As an example of industrial heritage, the Magpie Mine is a fine site and is a very popular tourist attraction; however, as I had realised when exploring various parts of the Sheffield Round Walk the previous year – such as Ecclesall Woods and the Porter Valley – industrial archaeology doesn’t greatly appeal to me and, instead of listening intently to our guide, I just enjoyed being outside in the fresh air and taking a few photographs of the day.

Grindstones made from Carboniferous limestone and Millstone Grit

The Building Stones of Sheffield - Part 4

A detail of a Kilkenny limestone seat on the Moor

By the time that the Sheffield U3A Geology Group had finished looking at the magnificent decorative stones in the interior of Sheffield Town Hall, they had encountered a wide variety of sandstones, limestones, marbles and granites and a few members decided that they had seen enough buildings for one day. 

Sheffield City Hall

Most of the group, however, stayed for the last leg of the walk around Sheffield city centre and, by request, we firstly went to have a quick look at Sheffield City Hall – built out of Darley Dale gritstone and opened in 1932. 

A detail of polished Ashburton marble

Briefly stopping to look at the stone indents used to repair bomb damage from WWII, the wall panelling provides further examples of Hopton Wood limestone and the door surrounds to the entrance shows Ashburton marble – as used in Sheffield Town Hall and Sheffield Central Library – at its best, with the fossil sponges being clearly visible. 

A gritstone lion inside Sheffield City Hall

The gritstone lions were originally sited on the exterior of Sheffield City Hall, but they were for some reason relocated to the offices of Tarmac in Matlock – when I first saw them when undertaking a survey of the RIGS (Regionally Geological Sites) in the Peak District National Park, when living in Bakewell

A general view of Charter Square

We then moved on to Sheffield's most recent public space at Charter Square, where we again encountered Chinese granite for the paving – designed to match the colour and texture of the Spanish and Portuguese granites previously used around Fargate

A Hall Dale sandstone seat in Charter Square

The sandstone used in the seating is the very distinctive Hall Dale sandstone, which in this instance has pink/buff variegation, and the rough boulders – which contain fine beds of coal and some unusual sedimentary structures. 

A rough block of sandstone with fine beds of coal

Although by now, a few members of the Sheffield U3A Geology Group had left to do some shopping or undertake other tasks – which they wouldn’t otherwise be able to do if they had been in the middle of the Peak District or other places – the remainder of the group accompanied me to take a good look at the seating in the Moor

Kilkenny limestone seating on the Moor

I reported on the first phase of this development for the German stone trade magazine StonePlus in 2010, which highlighted the work of Matt Black and Pip Hall, but I hadn’t noticed the seating areas at the top of the Moor before - a celebration of 100 years of stainless steel in Sheffield. 

Dry and wet Kilkenny limestone

Here, like the others at the bottom end of the Moor, the Kilkenny limestone seats have lost their original black colour produced by a fine honed finish – due to the natural degradation of the limestone by carbonic acid in rainwater and the atmosphere, but the fine examples of letter cutting and sandblasting can still be clearly seen.

A detail of sandblasted Kilkenny limestone

Tuesday, 17 July 2018

The Building Stones of Sheffield - Part 3

A bust of Queen Victoria inside Sheffield Town Hall

After a busy morning spent exploring some of Sheffield’s historic buildings and urban landscaping developments, including Sheffield Central Library and the Peace Gardens, the Sheffield U3A Geology Group continued their field trip to Sheffield city centre with a return visit to the library to briefly look at its interior. 

Travertine used for the floor in Sheffield Central Library

The reception area is notable for the use of beige coloured Italian travertine, a highly porous and open textured limestone that is formed in hot springs, for both the wall panels and the flooring, where it is used in conjunction with green and yellow varieties. 

A pilaster in Sheffield Central Library

In the entrance to the main library, the green variety of travertine forms capitals to pilasters formed of panels of Ashburton ‘marble’, a limestone from Devon that takes a polish and which was once highly favoured for decorating the interiors of grand buildings; however, despite its interior location, the surface has weathered over the years, with the loss of its high polish. 

A view of Sheffield Town Hall from the Peace Gardens

The next leg of the field trip continued with a walk along Surrey Street to Sheffield Town Hall – built in Stoke Hall gritstone from Grindleford - where we stopped briefly to look at the fa├žade above the main entrance, where the fine relief sculpture by Frederick W. Pomeroy depicts the industries of Sheffield. 

A detail of the frieze sculpture by Frederick W. Pomeroy

Inside the main entrance there are more frieze sculptures by Pomeroy and, although the low lighting in this busy thoroughfare makes it difficult to stop and examine the masonry closely, another stone – Ancaster limestone – can be seen here. 

Ancaster limestone in Sheffield Town Hall

Moving into the Main Hall, the group then spent 20 minutes admiring the magnificent decorative stones that have been lavishly used here, which include true marbles and polishable limestones from Connemara and Co. Cork in Ireland, along with others from Devon and Italy, as well as alabaster for the balustrades and Hopton Wood limestone for the wall panels. 

The Main Hall in Sheffield Town Hall

Quite strangely, the sandstone that has been used for elaborately carved stonework both below and above the ‘marble’ panelling was painted in preparation for the last visit of HM Queen Elizabeth II to Sheffield. Stone is a natural material that needs to ‘breathe’ and it is considered bad practice to paint stone in any building – on the outside or the inside - let alone a Grade I Listed building such as Sheffield Town Hall.

A detail of painted sandstone inside Sheffield Town Hall

Saturday, 14 July 2018

The Building Stones of Sheffield - Part 2

Fluvio-glacial cobbles at Sheffield Cathedral

After Sheffield Central Library, the next stop on the U3A Sheffield Geology Group field trip to Sheffield city centre was at the adjoining Tudor Square, where there are several large Crosland Hill sandstone planters designed by the artist Stephen Broadbent.

A large Crosland Hill sandstone planter in Tudor Square

Three hand-made plaster maquettes produced at 1:10 of the size of the final sculptures were laser scanned in Liverpool and each of the 173 individual stones were then carved at their full size by a robot at Johnsons Wellfield in Huddersfield, before being carefully assembled together.

An extract from the Building Stones of Sheffield - by Peter Kennett

Moving on to Fargate via Chapel Walk, the group then had a quick look at some of the various stones that were used during the remodelling of Sheffield’s main shopping street back in 1998. These include Spanish and Portuguese granite setts - laid by a gang of paviour masons from Naples - Caithness flagstone and Red Lazonby sandstone, with the latter showing considerable signs of wear and physical degradation. 

Grotesques on the gate posts in the forecourt of Sheffield Cathedral

Crossing Church Street from Fargate, we stopped at the gate posts on the corner of the cathedral forecourt - to appreciate the elaborately carved grotesques - before examining the coarse locally quarried Rivelin Grit, which has been used for Sheffield Cathedral and the Employment Tribunals Service building on East Parade. 

The statue of James Montgomery

The plinth to the James Montgomery statue in the old churchyard provides an example of Cornish grey granite, which was formed during the Hercynian period of mountain building - like the granites from the Iberian peninsular used on Fargate - but its colour and well formed feldspar crystals give it a very distinctive character. 

Examining the alabaster tomb at the rear of Sheffield Cathedral

To the rear of the cathedral next to Campo Lane, an alabaster tomb that was formerly sited inside the cathedral was moved to its current location in the 1960’s and, being soluble in rainwater, has subsequently disintegrated at an accelerated rate – with fractures in the stone being extensively weathered and its surfaces deeply furrowed. 

Historic buildings on St. Paul's Parade
The morning session was finished with a brief look at St. Paul’s Parade, where Browns brasserie provides a good example of Triassic Red St Bees sandstone, and a good look at the sandstones, granites and volcanic green slate that have been used in the Goodwin Fountain, which forms the centrepiece of the Peace Gardens.

Various stones used in the Goodwin Fountain

Here, as in Fargate, not all of the stones used have fared well after nearly twenty years of wetting and drying and, in winter, freezing and thawing. The Permian Clashach sandstone, in particular, has deteriorated to the extent that much of it really needs to be replaced – something that I suspected after I observed its very variable mineral content, when reporting on the project for Natural Stone Specialist soon after it was finished.

A detail of the Goodwin Fountain in Sheffield Peace Gardens

Tuesday, 10 July 2018

The Building Stones of Sheffield - Part 1

A general view of Sheaf Square

After a few months of relative inactivity since visiting Eyam in October 2017, the new year got off to a good start with a talk to Aston-cum-Aughton History Group followed by a walk around Sheffield city centre a couple of days later, to look at a wide variety of building stones with the Sheffield U3A Geology Group

The Building Stones of Sheffield

The itinerary for the field trips in 2018 had been discussed at the indoor meeting at the Commercial Inn in January and when I mentioned that I had been consulted as a ‘building stones specialist’ for the production of the “Building Stones of Sheffield” leaflet - which was suggested as the basis for a possible field trip - I was immediately delegated to lead this. 

A report on Fargate for Natural Stone Specialist

Having developed stone identification and matching skills, when setting up Triton Building Restoration Ltd. in London back in 1989, and having written several articles for various stone trade magazines in the UK and Germany – which described developments on Fargate, the Peace Gardens, Tudor Square, The Moor and Sheaf Square – this suited me down to the ground. 

Allen the Peregrine outside Sheffield Midland railway station

On a damp February morning, we convened at the ‘Allen the Peregrine' sculpture in Sheaf Square, where we could appreciate the topography formed by the Silkstone Rock here, and looked at the sandstones used to build the Sheffield Midland railway station and the magnificent cascades and fountain. 

Chinese 'granite' paving in Sheaf Square

We then headed up into Sheffield following the 'Gold Route' from Sheaf Square to Tudor Square via Howard Street – where various dark ‘granite’ from China has been used for the paving – and on the way we paused to have a very good look at Sheffield Central LibraryOpened in 1934, this Portland limestone clad steel framed structure is my favourite historic building in Sheffield, with fine examples of sculpture by Alfred and William Tory.

A view of Sheffield Central Library from Arundel Gate

To the elevation facing Arundel Gate, various cracks can be seen in the white glazed bricks and walking around the publicly visible parts of the building, there is plenty of evidence of a rusting steel frame and, in places, the stonework needs to be cleaned.

The main entrance to Sheffield Central Library

The medallions carved around the main entrance represent Literature, Music, Drama, Architecture, Sculpture, Painting, Mathematics, Chemistry and Astronomy and, high up on the splay, an Egyptian style motif depicts Knowledge. 

A general view of Sheffield Central Library

Unlike the sandstones that have been used for most of the historic buildings in Sheffield, the Portland limestone here has been very susceptible to the industrial pollution, which was once a big environmental problem in Sheffield; however, although this has resulted in the loss of a few millimetres of the surface of the limestone, this reveals an abundance of fossil oyster shells.

Weathered limestone reveals fossil oyster shells

Sunday, 8 July 2018

"Rotherham Red" on the X54 Bus Route

The trip to Eyam with the Sheffield U3A Geology Group proved to be my last day out in 2017 and the winter was spent catching up with the writing of brief reports on the places that I had visited since starting my investigation of St. Helen’s church in Treeton back in February 2016, which had turned into an intensive exploration of mediaeval churches in South Yorkshire and the surrounding counties. 

St. Helen's church in Treeton

I had been inspired by an encounter with Elmet Archaeological Services Ltd. in Wath-upon-Dearne, who used the nearby All Saints church to provide an introduction to standing buildings archaeology, and having previously worked for archaeologists at All Saints church in Pontefract and Brodsworth Hall – for a pre-restoration survey and a contribution to the Conservation Plan respectively – I thought that my experience made me suitable for undertaking this kind of work. 

The interior of St. Helen's church in Treeton

When the Aston-cum-Aughton History Group contacted me from the Sheffield libraries database to ask me to give a talk, I immediately thought of the investigations of the mediaeval churches in Treeton, Aston, Todwick and Harthill that I had undertaken in this part of Rotherham on the X54 bus – all of which lie on the red coloured Mexborough Rock, which is known locally as Rotherham Red sandstone. 

All Hallows church in Harthill

As an introduction to the geology, building stones and construction history of the medieval churches found within a short distance of the village of Aston, this talk went down very well with the full house and, on the strength of this, I have since been invited by one of the attendees to give a similar talk to the Friends of Rotherham Archives at Clifton Park Museum next year. 

The church of St. Peter and St. Paul in Todwick

In addition to the numerous illustrated talks and guided walks that I have delivered to various local history and conservation groups in South Yorkshire, I have also taught formal courses for the WEA in Rotherham and Sheffield and for Sheffield University adult educational services. 

All Saints church in Aston-cum-Aughton

At Beauchief Abbey, I encountered a group of archaeology students from Sheffield University – whose group leader sought my advice on their finds – and various vicars, churchwardens and architects have also expressed great interest in the work that I was doing. For professionals who need to undertake Continuing Professional Development courses and seminars, perhaps they could also learn a thing or two from me?

Thursday, 28 June 2018

A Trip to Eyam

Gigantoproductus brachiopod fossils in the Lower Shell Bed

I once lived in Bakewell and got to know the geology of the Peak District National Park quite well when I was commissioned to survey its RIGS (Regionally Important Geological Sites) and to identify places where tourism could be diverted away from ‘honeypots’ like Castleton.

A geological map of the area around Eyam

A month of intensive work only scratched the surface of its geology, but I nonetheless encountered a wide variety of sedimentary and igneous rocks and many spectacular landforms that I would recommend to prospective visitors to the Peak District.

Rose and Fossil Cottage

When I joined the Sheffield U3A Geology Group, I was very impressed by the wide variety of field trips that they undertook and, currently being without a car, it provided an opportunity to visit places that were otherwise inaccessible to me.

The Lydgate Graves

The October 2017 field trip to Eyam particularly interested me. Best known to tourists as the “plague village”, due to the part it played in containing an outbreak of the bubonic plague in 1665, there is also some interesting geology and geomorphology. 

Gathering around the information board at the Boundary Stone

The village is set on the Bowland Shale Formation, the bottommost strata of the Upper Carboniferous, and we started off here by looking at two of the very many places associated with the plague – Rose and Fossil Cottage and the Lydgate Graves. Making use of the Heritage Trails produced for the area around Stoney Middleton, we then followed a distinct ridge formed by the Eyam Limestone Formation to see the Boundary Stone

A view of Upper Carboniferous rocks from the Eyam Limestone ridge

From here, the younger Upper Carboniferous sandstones and siltstones rocks can be seen to form an escarpment to the north and, to the south, the flat reef limestone on which we were standing passes down into the Monsal Dale Limestone, which is seen in Middleton Dale

Lover's Leap in Middleton Dale

To the south side of Middleton Dale, the Monsal Dale Limestones have been extensively quarried and evidence of lead mining, lime kilns and evidence of other industries that have exploited the geological resources can be found along the gorge.

The Stoney Middleton Heritage Trail

The vertical cliff faces on the north side of Middleton Dale, especially at Castle Rock, show a cross section through the Eyam Limestones and the Monsal Dale Limestones, with variations in the facies, and differences between shallow and deeper water sediments can be clearly seen.

Castle Rock

Variations in colour and texture can be seen on a large scale and certain geological horizons such as the Lower Shell Bed in the Upper Monsal Dale Beds, where Gigantoproductus brachiopods can be found in great numbers, are quite spectacular. 

The Lower Shell Bed

In places, the path along Middleton Dale is quite precipitous – and not followed by everyone - but there are good examples of fluorite mineralisation, colonies of corals and fine views across to the quarries on its south side. 

A coral colony

Leaving Shining Cliff to walk back up to Eyam, the B6521 follows the course of a heavily wooded dry valley, and just before re-entering the village there is an exposure of thick beds of chert in the Eyam Limestone Formation - the last stopping point at the end of a very interesting day.

An examination of Eyam Limestone containing beds of chert