Wednesday, 30 October 2019

A Visit to Cadeby Quarry

A general view in Cadeby Quarry

During my investigation of the construction history and building stones of mediaeval churches in and around South Yorkshire, I have encountered numerous examples of dolomitic limestone from the Permian Cadeby Formation – with considerable variation in colour and texture - either as the principal building stone or used for dressings. 

General views of the exterior and interior of St. Helen's church

At St. Helen’s church in Treeton, where I live, this ‘Magnesian Limestone’ has been used for the C12 north arcade, the plinth to the C13 chancel, for windows in the later mediaeval additions and, most notably, for the early C16 addition to the tower. 

The south door at St. Helen's church

Some window tracery and the arch to the porch was replaced with Jurassic oolitic limestone in the C19 and, although Treeton was downwind of the Orgreave Coking Plant for many years, much of the remaining plain stone and simple mouldings are still in generally sound condition. 

Decaying limestone to the arch of the priest's door at St. Helen's church

The stone in the arch to the priest’s door on the north elevation of the chancel and the right hand moulded jamb of the Norman south door have decayed considerably and, like very much of the Rotherham Red sandstone - which is quite soft and has developed extensive cavernous decay - these elements need restoring. 

Cavernous decay in Rotherham Red sandstone

Although not party to the decision making process at St. Helen’s church, I was curious to know what dolomitic limestones were still generally available and in preparation for my trip to Pontefract with the Sheffield U3A Geology Group, I was also interested in the stone that had been used for recent work at Pontefract Castle

A view of the block store at Cadeby Quarry

The limestone used at St. Helen’s church is very pale in colour and my first step was to contact Cadeby Quarry, where I knew from past experience that much of the stone supplied here was of a similar colour. Much to my surprise Iain Kennedy, who I met at George Farrar when sourcing sandstone for potential use at All Saints church in Pontefract, invited me to come and visit the quarry and see the operations of Blockstone Ltd

The Dazzini chainsaw at work

Although this time, I wasn’t undertaking paid consultancy work, he kindly collected me from Warmsworth – which I had reached on the bus – and then showed me the block store and their Dazzini chainsaw in action, which is the sole method used for extracting limestone blocks here. 

The working quarry face at Cadeby Quarry

I hadn’t realised how large this quarry is and, although only a small part is now quarried for dimensional stone, I was very interested to learn that 13 separate beds are distinguished and that at least one of them possesses very distinctive ripple marks, which I had previously seen in several mediaeval churches. 

A display of various stones at Cadeby Quarry

For specifiers, both for new build and restoration work, their full range of stones are set out as panels in what is effectively a long wall, which provides a good indication of the variation in colour and texture likely to be encountered – something that is not readily determined in the 150 mm square samples that are typically sent out in the post. 

A detail of dolomitic limestone displays at Cadeby Quarry

I didn’t knowingly get to see the Site of Special Scientific Interest (SSSI), which is described in the Geological Conservation Review but a visit to a quarry always adds a bit more to my knowledge of geology and, on this occasion, I spotted another bryozoan reef.

A bryozoan reef at Cadeby Quarry

On the way back home, having already got a couple of samples in my rucksack, I took advantage of my wait for the X78 bus back to Rotherham by popping in to the showroom of Warmsworth Stone Ltd. – where I was given more samples from the Hazel Lane Quarry, which I had previously visited when undertaking the Doncaster Geodiversity Assessment

The building magnesian limestones of the British Isles

When finally arriving home, I completed my day by making further investigations about dolomitic limestone quarries that were listed in my copy of the Building Research Establishment (BRE) publication - “Building magnesian limestones of the British Isles”. 

The brochure for Tadcaster Building Limestone

Even though I was able to obtain further samples from the Highmoor Quarry in Tadcaster, which supplied stone for recent work to Selby Abbey, I discovered that several quarries listed were closed, no longer had planning permission or didn't respond to my request – a situation that may account for the use of Bath Stone for modern repairs to churches that are built of distinctly yellow dolomitic limestone, which I have seen recently.

Dolomitic limestone samples from Cadeby, Tadcaster and Hampole

Friday, 25 October 2019

Vernacular Architecture in Alport

The hamlet of Alport has some very interesting geology and, when quickly exploring its vernacular architecture, I discovered that it has very many interesting historic buildings that have Grade II Listed status. 

A general view in Alport

This is quite surprising, given the very small size of this settlement, but its setting at the confluence of the River Lathkill and River Bradford made it a centre of local industry, with several mills being once located here and several lead mines nearby. 

Rock House

Several buildings have been listed only for their group value, but Rock House, Monks Hall and the barn attached to Hill View – with its Doric columns and large decorative plaques – have plenty to interest the architectural historian. 

The barn at Hill View

The predominant building materials are Carboniferous Limestone for general walling, massive Millstone Grit for ashlar in the best buildings and for dressings, with flaggy gritstone for the roofs. 

Birchover stone at Lathkilldale Farmhouse and Fern Glen

Where used for ashlar, as in Lathkill Dale Farmhouse, Fern Glen and the west extension of Rock House, the gritstone is pink/red and probably comes from nearby Birchover, where the stone very often has this colour. 

Boundary walls constructed in tufa

The Alport tufa has also been used widely for boundary walls, where the irregularly sized and shaped blocks are laid as rubble walling – sometimes with elongated flat stones from the Millstone Grit to add stability. 

Some rendered buildings in Alport

I only spent 20 minutes wandering around Alport, while waiting for my bus back to Bakewell, and didn’t have enough time to stop and closely examine the stonework of any of the buildings that I saw; however, I did notice that several buildings were rendered – which is very unusual in the Peak District National Park - and I therefore assume that the walls of these are built in tufa

A bridge over the River Lathkill

Having spent a full day exploring Youlgreave and Alport, I came home with several hundred photos. When editing these, I discovered that the stones used to construct the bridge across the River Lathkill, downstream from Alport Lane, have all been clearly numbered – a little detail that adds a further point of interest to an already fascinating place.

Numbered stones on a bridge in Alport

Tuesday, 22 October 2019

Geology in Alport

Rapids in the River Lathkill at Alport

When planning my trip to Youlgrave, to investigate the building stones in the village and the construction history of All Saints church, I had to organise my time around the irregular rural bus services and decided to have a look at the geology around Alport
Back in 1995, I had undertaken a survey of the RIGS (Regionally Important Geological Sites) in the Peak District National Park and had briefly investigated Lathkill Dale and Bradford Dale, whose confluence is at Alport, but I don’t recall seeing the exposures of Pleistocene tufa here. 

A view across lower Lathkill Dale from Alport Lane

During trips to Monsal Dale and Matlock Bath with the Sheffield U3A Geology Group, I had previously encountered tufa – where the springs are still exploited commercially as petrifying wells for the tourists at the latter – but the Alport tufa was reputedly the largest deposit in Derbyshire and was widely used for buildings in the area. 

A general view of Tufa Rock

Having finished exploring All Saints church, I walked down to Alport and immediately went to find the tufa to the north-east of Rock House on Alport Lane, which has been given the name Tufa Rock. Formed by precipitation of calcium carbonate from springs, the exposures here are several metres high and, although much of the rock is overgrown, it is possible to study them from the track that passes the side of the houses. 

A close up view of Tufa Rock

I didn’t examine it closely, but the irregularly bedded mass and very open, porous texture distinguishes it from the Carboniferous limestone - the well bedded Eyam Limestone Formation – that forms crags on the east side of the wide valley to the north of Rock House. 

A view up Lathkill Dale from Tufa Rock

After taking a few photographs, I crossed to the west side of the valley in which the River Lathkill flows and made my way north along Lathkill Dale, where I hoped to be be able to get to Conksbury Bridge, where I had previously encountered vesicular basalt in the area that rises above the path, as well as blocks of limestone in the river bed, which were packed full of fossil brachiopod shells

Crags of the Eyam Limestone Formation in Lathkill Dale

Not having an Ordnance Survey map with me, and being unable to remember exactly where I had found these rock exposures, I set of walking as fast as I could; however, although I saw outcrops of the Eyam Limestone in the crags on the east side of Lathkill Dale, when consulting a fellow walker with a detailed map, I realised that I wouldn’t have the time to explore the area fully and turned back to Alport. 

A weir on the River Lathkill

Still with time before I had to catch my bus back to Bakewell, I then followed the River Lathkill along its course to the point where it meets the River Bradford, and during which it falls over weirs, possible tufa barrages, and ledges of limestone that form shallow rapids in the river bed below the road bridge on Alport Lane. 

The River Lathkill below Alport Lane bridge

Walking a short distance up Bradford Dale, I soon encountered Rheinstor Rock, which is composed of massive beds of the Eyam Limestone Formation – as marked on the geological map - and is a very popular locality for rock climbers.

Climbers at Rheinstor Rock

I didn’t examine the outcrop closely, to determine the presence of fossils and therefore confirm that it was Carboniferous limestone, but the rock seemed to be full of voids and I did wonder if this might be in fact another outcrop of the tufa.

Rheinstor Rock

Saturday, 19 October 2019

All Saints Church Youlgrave - Memorials

A detail of the effigy of Thomas Cokayne

During my investigation of mediaeval churches, in South Yorkshire and the surrounding counties, although I have principally concentrated on the fabric and the building stones that have been used in their construction – to further my interests in standing buildings archaeology - I like to see their various memorials. 

War memorials in the nave

As a geologist, the Neoclassical wall memorials made from white and black marbles generally don’t interest me and I much prefer the wild colours and textures that can been found in alabaster, which was once extensively mined in Derbyshire and worked in Nottinghamshire

Monuments to church vergers

All Saints church in Youlgrave has several fine examples of alabaster, with the most recent examples being found in the simple plaques in the south aisle, which commemorate church vergers and the more elaborate memorials to WW1 and WW2, which can be found in the north wall of the extended nave. 

The memorial to Roger Looe and his family

In the north aisle, the Jacobean wall memorial to Roger Rooe of Alport, who died in 1613, shows him and his wife on their knees facing each other across a prayer desk, with their eight children in a line below. The tradition of the time was to paint the alabaster but, here, the colours on the various figures have largely disappeared. 

The reredos in the north aisle

At the east end of the nave, there is an altar whose reredos commemorates Robert Gilbert and his wife Joan, who died in 1492. The central figure of a Virgin and Child is flanked by Robert to the left, with his seven sons and Joan, to the right, with her ten daughters. 

The tomb of Thomas Cokayne

Moving into the chancel, the chest tomb depicts Thomas Cokayne in the full armour of the period, who died in a fight with Thomas Burdett in 1488 after a quarrel over a marriage settlement. It is unusual in that the effigy is much smaller than those typically seen, which is apparently because he died before his father. 

The effigy of Sir John Rossington

The oldest memorial in All Saints church, also in the chancel, dates to the C14 and is thought to depict Sir John Rossington, who is holding a heart in his hands, has his legs crossed and his feet resting on a dog; however, on this occasion, the stone is not alabaster but Permian dolomitic limestone, which I have often seen in South Yorkshire and the surrounding counties.

A detail of the effigy of Sir John Rossington

Sunday, 13 October 2019

All Saints Church Youlgrave - Interior

A detail of a capital in the north arcade

The exterior of All Saints church in Youlgrave has many points of interest for the standing buildings archaeologist and architectural historian but, as a geologist, I particularly liked the mix of Carboniferous Limestone and Millstone Grit in the north aisle – not least because I think that I could use this a stopping point on a Sheffield U3A Geology Group field trip. 

The south door

Entering the porch, the sturdy looking pointed arch to the south doorway has quite crude mouldings and chamfers, which are an indication of a change from late Norman to the Early English Gothic architectural style, and this transition can also be seen in the arcades. 

A general view of the south arcade

The south arcade has stout circular columns, with octagonal section scalloped capitals, from which spring round arches and are typical of the late Norman period – dated c.1150 to 1170 by the church guide book. 

A view west along the nave

The north arcade, however, is significantly different. Although also round, the columns are slimmer than those in the south arcade, the capitals are square with more elaborate decoration – including volutes, foliage and heads – and the arches above are slightly pointed. 

Distortion of the arch and column in the north arcade

Looking more closely at the north arcade, and at other masonry in the church, it can also be seen that there has been some structural movement over the years. Although not as obvious as that seen at Selby Abbey, the arch to the westernmost bay is distorted and there is a distinct lean of the column towards the east; however, unlike at Selby Abbey, All Saints church is built on solid limestone and the settlement is probably due to an old lead mine that runs under the church. 

Sculpted figures in the nave 

Looking at the masonry in the nave, very large, well squared blocks of gritstone rise above the arcades to form the clerestory and this can also been seen in the walls that stretch westwards to the tower – with the north wall incorporating a 12th century sculpture and another C17 sculpture, found in the graveyard, being attached to the wall. 

The font

The very unusual C12 font, and a piscina that has been relocated to the north aisle, provide further points of interest to the general tourist but I was particularly interested in the various monuments and memorials that can be found in All Saints church.

A piscina