Friday, 28 February 2020

An Exploration of Ashover Village

A general view of Ashover

The picturesque village of Ashover is a very popular geology field trip location for university students, geological societies - and general tourists - but the rocks that now serve as an excellent educational resource once made great profits for various businesses. 

Arriving in Ashover on the path from Butts Quarry

The Romans first exploited the many lead rakes that are exposed here, with the heyday of the lead mining industry being in the last quarter of the C18, and the limestone was considered to be sufficiently valuable to build a light railway between Butts Quarry and Clay Cross.

Butts House

Arriving in the village from Butts Quarry, the first historic building that I encountered was Butts House, a late Grade II Listed C17 house that is built out of Ashover Grit, with a Welsh slate roof. 

Prestwood on Butts Road

Carrying along Butts Road, a house named Prestwood caught my eye, not least because of the very pale colour of the gritstone that has been used to build it, which is unlike anything that I have encountered and made me wonder if had been limewashed

A general view along Butts Road

In most places that I have encountered where Carboniferous Limestone comprises the underlying geology - particularly the Peak District National Park - gritstone is mainly used for quoins and dressings, with only the better quality buildings built entirely in gritstone, but along Butts Road, none of the cottages are built in limestone. 

Various cottages on Butts Road

Further west, around Stanton Moor and Darley Dale, several working quarries and many disused ones are located on the Ashover Grit, with this stone having developed an extremely good reputation for its durability and uniform characteristics. 

A detail of a boundary wall on Butts Road

Where rubble stone has been used in boundary walling, however, those stones exposed to rising groundwater or road salt have degraded considerably, with most of the edges and corners being rounded by weathering. 

Church Street

Turning up Church Street, there is a concentration of listed buildings, including the mid C18 West Bank and, again, all of the buildings I saw are constructed in gritstone and not limestone. 

A view up Church Street

The most substantial buildings are found around All Saints church, with the Old Rectory being remodelled in the C18 from an earlier building and still retaining its stone tile roof, although it has been extended in the C19 and C20. 

The Old Rectory

Next to the church is The Crispin Inn, which is partially rendered, dates back to the C17 although, according to a sign on its exterior, the building can be traced back to 1419 when the men of Ashover returned to the village after the Battle of Agincourt

A sign at The Crispin Inn

Across the road is the former National Girl’s School, dated 1845, which has a Dutch gable and is built in gritstone ashlar, with horizontal tool marks, and is now used as the church hall and a community centre.

The former National Girl's School

Saturday, 22 February 2020

Geology in Ashover

Samples of tuff from the Fallgate Volcanic Formation

When visiting Fishlake, to explore St. Cuthbert’s church, the most interesting feature for a geologist was the remnant of the Norman church built in cobbles, which were probably sourced from the glaciofluvial deposit at nearby Thorne; however, the village of Ashover, which I visited the following day, is a very popular field trip destination. 
I first went there as an undergraduate geologist at Nottingham University, back in 1979, but the only thing that I remember is looking down into the valley formed by the River Amber, which cuts through the Ashover anticline to reveal an inlier of Dinantian rocks. 

A map in the Geological Excursions in the Sheffield Region

Although the main objective of my trip was to visit All Saints church, I took with me an extract from Geological Excursions in the Sheffield Region with details of geological sites in Ashover, in the event that I had time to investigate them. 

Iron stained sediment at Marsh Brook

Getting off the X17 bus from Chesterfield at Kelstedge, which is marked on the British Geological Survey map as being sited on the Bowland Shale Formation overlain by Quaternary till, I walked down towards Ashover and had a quick look at the area around Marsh Brook; however; seeing only iron stained sediment in the stream but no shale, I carried on to the bottom of the hill and went in search for Butts Quarry

A general view of Butts Quarry

This substantial quarry exposes a section of the Eyam Limestone Formation above the Monsal Dale Limestone Formation and is considered to be a good locality to find an assemblage of fossils and minerals too. Although I didn’t take the time to study the limestone in detail, in places there is mineralisation along the joints, with distinctive iron staining.

Mineralisation on joint planes at Butts Quarry

Crossing Marsh Brook again near to where it joins the River Amber, I headed into Ashover and, after treating myself to an ice cream, I headed south down Hockley Lane to try and find a cutting to Hockley Quarry, which is listed in my excursion guide as the best place to see the tuff in the Fallgate Volcanic Formation

A view across the Amber Valley from Hockley Lane

Not seeing any sign of the entrance to the old quarry, I made my way down to the river again, hoping that I would see some tuff exposed in the river bank, but the clapper bridge and ford was the main point of interest that I saw. Crossing the bridge and continuing south-east down to Demonsdale Farm, I turned up Jerting Street on the south side of the river and headed back in the same direction that I had come from. 

A clapper bridge and ford across the River Amber

Jerting Street and Hockley Lane on the other side of the valley approximately follow the boundary of the Fallgate Volcanic Formation, which forms gently sloping ground either side of the river, and the Monsal Dale limestone, which forms steeper ground above it. Higher still, on the south side of the valley, younger Eyam Limestone forms a line of crags, whose upper part comprises a knoll reef, but I didn’t leave the road to go and study it in any detail. 

Crags in the Eyam Limestone Formation

Looking down into the bottom of the valley, the grass appeared very lush and green compared to the scrubby grassland on the upper slopes and this, as well as the distinct change in the slope, is a good indication of the position of the underlying tuff, even though no rock exposures are seen. 

Lower slopes formed by the Fallgate Volcanic Formation

At the point where Jerting Street reaches the brow of the hill, I took a very sharp right turn to follow what is considered to be an ancient trackway, which at this point is paved with gritstone slabs and runs directly across a field. 

The trackway leading to the River Amber

Following this path down to the River Amber, I finally encountered a lengthy exposure of bedded tuff, which has been exposed by a combination of the wear by very many feet and natural erosion by water that must sometimes flow down it. 

An exposure of tuff in the Fallgate Volcanic Formation

Thursday, 20 February 2020

St. Cuthbert's Church Fishlake - Part 4

A view along the nave to the chancel

Once inside St. Cuthbert’s church in Fishlake, the first thing that caught my eye was a large open pit at the west end of the south aisle, in which is set the central heating boiler on a raised plinth – with all of the pipes exposed – and it made me wonder why someone had designed it like this and how on earth it could have met with approval. 

The central heating boiler in the south aisle

Looking down the nave, the 5-bay arcades date to the C13 and have circular columns and capitals and the original masonry is formed of very irregularly squared and coursed blocks of dolomitic limestone, which contrasts with the C15 masonry that forms the clerestory above. 

Masonry to the north aisle and clerestory above

The chancel arch is considered to be C14 and, although not marked with an old roof line in the nave, the pattern of the masonry above the stringcourse appears to have been disrupted by rebuilding work associated with the new C15 roof. At the opposite end of the nave, there is an extremely tall tower arch, with compound piers, which is also C15 in date. 

A view along the nave to the tower

At the east end of the aisles, there are very wide four centred arches that lead into the chapels beyond, which to me suggested a late Perpendicular Gothic style but which Pevsner attributes to the Decorated Gothic from the C14. 

The arch between the south aisle and the Trinity Chapel

Inside the chancel, flat three centred arches connect it with the chapels to either side and, as is seen in the adjacent arches to the aisles, they are slightly lopsided and there has been some settlement of the structure here. 

Three centred arches linking the chancel with the north and south chapels

As at Selby Abbey, where some of the arches are extremely distorted, this is due to the fact that the church is built on unconsolidated Quaternary deposits - here the silt and clay of the Hemingbrough Glaciolacustrine Formation, and not solid rock. 

A view of the chancel from the altar

Like the aisles and the outer faces of the arcades, the walls of the chancel have been plastered, but not painted, and much of this has fallen off with no attempt made to repair it, giving it a very unsightly appearance 

A blocked arch in the north wall of the chancel

Throughout the church, the York stone paving and stonework of the lower parts of the walls show distinct signs of damp and efflorescence, with degradation of the stonework that results from cycles of wetting and drying and the recrystallization of salts in the pores of the stone.

Disintegrating stone at the base of a compound pier

There are various interesting features in the chancel, including the impressive tomb-chest to Richard Marshall, but the overall impression is that this church has seen much better days. Like at St. Helen's church in Treeton, the parishioners are probably struggling to maintain it in good condition, which is a common problem for the guardians of Grade I Listed churches such as this.

A detail of the Richard Marshall tomb showing algal growth

Saturday, 15 February 2020

St. Cuthbert's Church Fishlake - Part 3

A detail of stone carving to the south door

An investigation of the exterior of St. Cuthbert’s church in Fishlake reveals a few features that are of interest to the architectural historian or archaeologist and, as a geologist, I was particularly pleased to see some glaciofluvial cobbles used in the masonry surronding the C12 doorway. 

The porch

Stopping to briefly examine the surround to the porch, which is made of a Jurassic oolitic limestone and not Permian dolomitic limestone, which is found in the rest of the church. Although I have seen no reference to any restoration having taken place, I have encountered many examples of porches and other elements that were restored with oolitic limestone in the C19, including those in Treeton, Conisbrough and Kirk Sandall

A detail of oolitic limestone to the porch

Victorian architects still had plenty of sources of dolomitic limestone in South Yorkshire, but I have often suspected that the rapid deterioration of the Anston stone at the Palace of Westminster may have influenced their choice of material for restoring carved masonry. 

Headstops on the porch

Oolitic limestone is susceptible to sulphurous pollutants in the atmosphere when located downwind of industrial areas and, although not so advanced as at St. Oswald’s church in Kirk Sandall, the carved headstops to the porch are starting to delaminate and decay. 

A general view of the south door

Once inside the porch, the Norman origins of the church become quite clear in the magnificent south door, which Pevsner describes as “perhaps the most lavishly decorated in Yorkshire”. 

A close up view

I have only seen a better example of late Norman stone carving on the west door of Rochester Cathedral, where the Caen stone used is very suited to this purpose, and the beakheads carved in sandstone at St. John the Baptist’s church in Adel are of similar quality. 

Orders with capitals to the left of the door

The arch is laid out in four orders, with elaborately decorated capitals to the columns with various carvings of seated figures, human heads, animals and leaves to the voussoirs – some of which have been eroded beyond recognition. 

A detail of carved capitals

I only spent the time to take a few general record photos, although it would make a good project to photograph each carving with appropriate artificial lighting, but a thorough account of this has been written by Rita Wood for the Corpus of Romanesque Sculpture of Britain and Ireland

A detail of a lion

Unlike very many churches that have notable examples of Norman sculpture forming part of their south doorways, St. Cuthbert’s church is always open during the daytime for visitors, and it is worth making the effort to get to see this wonderful work of art.

A detail of figurative sculpture

Friday, 14 February 2020

St. Cuthbert's Church Fishlake - Part 2

The south elevation of St. Cuthbert's church

Continuing with my investigation of the exterior of St. Cuthbert’s church in Fishlake, the south wall of the chancel and the south chapel are built in dolomitic limestone ashlar, with the chapel having wide 5-light windows that have four centred arches and Decorated Gothic tracery

The south window of the south chapel

The south wall of the chancel, however, contains a small remnant of the original Norman church, which is thought to have been built during the reign of Henry II c.1175. A very plain round headed priest’s door is preserved at the angle of the chancel and the south chapel, with walling comprising angular rubble and cobbles – as also seen in Kirk Sandal, Hatfield and Thorne

The priest's door in the south wall of the chancel

Although I didn’t investigate closely, using a hand lens, steel knife and hydrochloric acid, the cobbles appear to be mainly sandstone with a few that look like flint, but these were out of reach.

A flint cobble in C12 masonry to the chancel

If flint, then this would suggest that its source would be a glaciofluvial deposit such as those found at Thorne and Lindholme, which are believed to provide strong evidence of the southern limit of the Vale of York glacier

Windows in the south wall of the chancel

Looking at the south windows of the chancel, the arched upper windows are late Perpendicular Gothic in style and are identical to those of the north wall, throughout the clerestory and to the east end of the south aisle; however, the flat headed 5-light window below appears very incongruous in its size, position and proportions. 

A gargoyle on the south chapel

After taking a good look at the weathered gargoyle on the corner of the south chapel, which reminds me of The Scream by Edvard Munch in the way that the figure is clutching its head, I moved on to the south aisle. 

Various stone repairs

My first impression of St. Cuthbert’s church, like St. Lawrence in Hatfield, was that it was predominantly a late C15 structure built in limestone that seems consistent in colour, texture and the degree of weathering, apart from obviously recent essential restoration work. 

Windows in the south aisle

The south aisle contains three windows with different designs, one of which at least would be interpreted as being Decorated Gothic, and these all appear to blend in perfectly with the surrounding ashlar masonry. Now having experience of seeing very many medieval churches, I would have said the walling was of a later Perpendicular Gothic style and it made me wonder if the mediaeval church builders practised sympathetic restoration or undertook work that today would be described as retro

Sculptures on the south elevation of the tower

Apart from the gargoyle on the south chapel, most of the sculptures are seen in the clerestory, with headstops to the windows and two gargoyles draining the roof, and on the tower there is a weathered falcon and fetterlock and a crown surmounting a rose on the south elevation, with a statue of St. Cuthbert holding the head of King Oswald on the west elevation.

The statue of St. Cuthbert