Friday, 12 July 2019

A Geology Field Trip in Monsal Dale


Gigantoproductus brachiopods in a dry stone wall

After a couple of visits to Barnsley, to explore the villages of Worsbrough and Cawthorne, and their mediaeval churches, my next day out in April was to Monsal Dale in the Peak District National Park with the Sheffield U3A Geology Group.

Gathering at Monsal Head

Sixteen members of the Group convened at Monsal Head for the usual 10:30 start and, after a brief discussion of the formation of the horse shoe shaped valley that we could see below, we headed off to find the path that would take us up to Hob’s House.

Arriving at Hob's House

Having prepared this trip a couple of weeks earlier, with my colleague Paul May, I did have some concerns that this first part of the walk – to explore the Hob’s House landslip – might be demanding for some members of the Group, given the average age of over 70; however, the whole Group easily overcame all of the obstacles that I had perceived as a potential problem during our reconnaissance.

The Monsal Dale Limestone Formation at  Hob's House

When at our destination, the Group did sit down for a brief rest but we followed this with a good examination of the numerous corals and the very distinct beds of chert. Having provided the Group with an explanation of the chemical difference between the limestone and the chert, Paul May then applied a hydrochloric acid test to samples of both of these rocks.

Undertaking a hydrochloric acid test

Making our way back down to the River Wye, again without incident, we had a good look at the exposure of tufa that had been exposed by a fallen tree. Again, hydrochloric acid was used to test for carbonate minerals and those that had brought their hand lenses were able to examine the very porous nature of this rock.

Examining an exposure of tufa on the river bank

Taking lunch on the old river terrace, we took the opportunity pass around a few geological maps that had been brought along, in preparation for the next part of the filed trip - to try and find some exposures of basalt along the lower reaches of Monsal Dale.

Examining sediments in the river bank

The afternoon session commenced with an examination of the river bank sediments and then we took a leisurely walk along the River Wye, where we encountered various riffles in the river, springs with tufa deposits and remnants of industry.

The Group stops to have a look at riffles in the bed of the River Wye

Arriving at the boggy ground underlain by the Lees Bottom Lava Member, a few of the Group decided to walk back to Monsal Head along the route we had already traversed, instead of tackling another moderately steep hill that I had previously found quite demanding.

Examining a stream that passes over the Lees Bottom Lava Member

Carrying on, we discovered a species of plant/fungus that nobody could identify, found a dry stone wall, where the coping stones were packed full of Gigantoproductus brachiopods, and then rummaged through an old waste tip along the Putfield Hill vein where several good examples of calcite and barytes were found.

Exploring an old waste tip for minerals

Finishing our return journey on the path that descends to Headstone Viaduct, now knowing where to look, we encountered a few basalt boulders, one of which must have been previously discovered by a group of geologists, as it had been split in half. Although very heavy, we didn't have far to go until the end of our trip  and it now forms part of my growing rock collection.

A split boulder of basalt

All Saints Church in Cawthorne


The head of a Saxon cross in the east wall of the north chapel

When I visited Cawthorne on the 13th of April 2019, after visiting Cannon Hall and having a brief wander around the village, I was informed by someone at the Victoria Jubilee Museum that All Saints church was not open for the general public until the following week. 

The approach to the north side of All Saints church from Church Street

I had made a great effort to get there from Treeton by public transport, which had taken nearly 2½ hours, and I must say that I was annoyed at myself for misunderstanding its opening hours; however, I had been having a thoroughly good day out and I was content to briefly explore its churchyard and photograph its exterior. 

A view of the walling and lancet windows to the north chapel

Approaching the church from the fountain on Church Street, the first view is of the late C13 chapel, with most of its masonry being laminated buff/dark brown sandstone, which is very similar to that seen in boundary walls and general walling in vernacular architecture around the village. 

A detail of a lancet window to the north chapel

The massive dressings to the lancet windows are of a much coarser grained variety, brown to orange and colour and strongly cross-bedded, with softer beds being differentially weathered. The wall to the chapel has been heightened with massive stone that is yellowish in colour and similar to that used in the adjacent north aisle to the west, whose windows are considered to be late C15 Perpendicular Gothic in style by Pevsner

The north aisle

Moving further in an anticlockwise direction, the C15 Perpendicular Gothic tower is built entirely of medium/coarse grained cross-bedded sandstone that possesses considerable colour variation within the same block of stone – varying from yellowish to dark brown. 

The tower

Together with the sandstone used for the chapel window dressings, the weathering characteristics – especially the differential weathering to expose the cross-bedding – is like that seen in the salvaged masonry which has been used in Fairyland at Cannon Hall. 

A view of the stonework around the door in the west face of the tower

Carrying around to the porch, the whole of the south elevation, the chancel and the upper east end of the north chapel was rebuilt during the restoration by Bodley and Garner, 1875-80. All of the stonework is of yet another distinctly yellow sandstone, which is generally very uniform in colour and texture. 

A view of the porch and south aisle

Its colour and pattern of weathering is just like that found in the Victorian chancel, and mediaeval masonry, at All Saints church in Silkstone, which is just over 2 km away. In Both Cawthorne and Silkstone, substantial old quarries on the Silkstone Rock once existed and there was another on the Parkgate Rock, a few hundred metres south of old Cawthorne village, and it is quite likely that one or more of these supplied stone for Cawthorne’s old church. 

A general view from the south-east

According to an account of the history of Cawthorne in 1882 by Reverend Charles Tiplady Pratt, the vicar of Cawthorne, all of the stone for the Victorian work came from Thurlstone and Huddersfield – distances of 7 km and 18 km respectively as the crow flies; however, having seen many buildings built out of Grenoside Sandstone and Rough Rock, upon which these towns sit, its construction history further interests me and I would like to have a closer look at these. 

A reconstructed Saxon cross

Of the many mediaeval churches that I have visited, the extensive Victorian restoration takes away much of its archaeological interest but the east end of the chancel incorporates the head of a Saxon cross and another, with fragments of a shaft, has been incorporated into a reconstruction in the churchyard. 

Floriated crosses set into the churchyard wall

In the north-east corner of the churchyard, a series of grave slabs with floriated crosses that were discovered in the fabric of the church have been reset into the wall and there is a very impressive vault, built for the Spencer-Stanhope family.

The Spencer-Stanhope family vault

Wednesday, 10 July 2019

An Exploration of Cawthorne Village


A grotesque on Swift Cottages

Arriving in Cawthorne on the No. 92 bus from Doncaster at Tivy Dale Road/The Park, South Lodge, c.1820, provides an example of what I assume to be Parkgate Rock and, it is possible that this stone was used to build Cannon Hall

South Lodge

Described by the British Geological Survey as being quite distinctive for its very strong cross-bedding, Parkgate Rock was formed in a river channel and is massive in nature, enabling it to be cut into large blocks. This contrasts with the flaggy sandstone used for the stone slates

Walling alongside Tanyard Beck

Walking towards the centre of the old village, dry stone walls and general walling for the historic vernacular architecture use similar thin bedded sandstone and it is probable that this was not quarried from the Parkgate Rock. 

Vernacular architecture on Tivy Dale

After more than 3 years of investigating mediaeval churches and their surrounding villages, in and around South Yorkshire, I have encountered very many examples of sandstone from the Millstone Grit and Coal Measures and, due to their close similarities in colour and texture, it is generally extremely difficult to assign a building stone to a particular rock formation. 

Vernacular architecture on Taylor Hill

The numerous quarries that were often opened to serve local needs are now mostly filled in and redeveloped or, if still existing, completely overgrown or on private land and therefore inaccessible. Without known examples of a particular sandstone for reference - where it is possible to examine its physical characteristics in a large expanse of rock face – or documentary evidence, this is usually just an educated guess

Sculpted panels by Samuel Swift

Continuing further up Taylor Hill, the pattern of stonework in various simple houses is as previously seen and the most interesting features are the Grade II Listed garden wall, containing C19 sculpted panels by Samuel Swift and Swift Cottages on the opposite side of the road, which are surprisingly ornate. 

Sculpture at Swift Cottages

The precisely squared and coursed masonry is far superior to that used for cottages of a similar age elsewhere in the village, with coarser gritty sandstone, of uniform colour and texture, used for the oriel windows, dressings and various sculptures. 

A memorial to Queen Victoria

At the top of the hill, the Victoria Jubilee Museum has some interesting monuments, a large carved sandstone boulder commemorating the Diamond Jubilee of Queen Victoria and her subsequent death, and a Portland limestone war memorial that was made by Jack Swift, who had followed in the family stone masonry tradition. 

Cawthorne war memorial

Outside the museum, two large rocks on the entrance steps caught my eye, which a close examination reveals to be basalt. One of the museum volunteers, who was preparing for a private function before the official opening the next day, informed me that he thought it may have been from Iceland; however, the smooth polished surfaces are consistent with them being glacial erratics, as mentioned in the British Geological Survey memoir. 

Glacial erratics at the Victoria Jubilee Museum

Unexpectedly, I was invited into the function and was told that All Saints church, which was next on my agenda, was also not open until the following week. Resigning myself to the fact that I would have to come back to Cawthorne at another time – to look at the museum’s contents and the interior of the church – I continued to enjoy their hospitality. 

The fountain on Church Street

Giving myself enough time to look at the ornate fountain on Church Street, in the form of a Viking cross, before having a quick look at the exterior of All Saints church and the various monuments in the churchyard and then having a quick pint of bitter at the Spencer Arms, while waiting to catch my bus home.

A pint of Timothy Taylor's Landlord bitter

Sunday, 7 July 2019

A Trip to Cawthorne - Cannon Hall


A view of the south elevation of Cannon Hall

April 2019, like March, had generally dry and warm weather and proved to be another busy month. Starting with a trip to Worsbrough, a few days later I travelled even further into Barnsley, with a trip to Cannon Hall and the village of Cawthorne which, involving two changes of public transport and a journey time of over two 2½ hours in each direction, required a full day out. 


The geology around Cawthorne and Cannon Hall

The oldest part of Cawthorne, including All Saints church, is set on high ground formed by the Parkgate Rock, and an old quarry is marked on the 1906 Ordnance Survey map, less than 350 m due south of the village. 


An old map of Cannon Hall

Alighting from the No.92 bus from Doncaster at Tivy Dale Road, a walk of 1 km takes you across parkland to Cannon Hall, which is set on a ridge of Pennine Lower Coal Measures Formation sandstone. An 1894 map records an old quarry less than 200 m away from the house, which was built in the late C17. 


Flaggy sandstone used in a dry stone retaining wall

At the western approach to the house, there is a formal garden with a dry stone retaining wall built out of light brown flaggy sandstone - probably from the estate quarry - which contains many dark brown/purple coloured stones that indicate the presence of high levels of iron – a reflection of the fortunes that were made by owners of Cannon Hall from the local iron industry. 


A general view of the main house at Cannon Hall

Viewed from a distance, the stonework to the upper floor of the wings of Cannon Hall – added in 1804 to the earlier wings of 1768 – looks quite different to that of the original house, which is comparatively pale in colour. 


The original 5 bay house at Cannon Hall

Looking closely at the latter, the heavily eroded masonry has been extensively restored in a very unusual way. The mortar mix used for general pointing, with coarse aggregate, has also been applied in large areas of masonry – as I had seen with brick repairs in the building restoration industry in London. 


A detail of mortar repairs to the stonework

Inside Cannon Hall, I noted fireplaces built in polished Derbyshire crinoidal limestone and Italian marble but, from an architectural perspective, the house is quite plain and the most interesting stonework can be seen in Fairyland - set in the parkland a short distance from the house.. 


A salvaged arch and pond in Fairyland

This landscaped ornamental garden, with its water features, makes use of stonework that is thought to have been salvaged from the ruins of mediaeval churches in Cawthorne and Silkstone, as well as an arch from the demolished Chantrey Tower at Cook's Study Hill, near Huddersfield.


Salvaged window tracery an a door arch in Fairyland

The arches and Perpendicular tracery, however, didn’t look like those that I had seen at All Saints church in Silkstone but the stone seen here is strongly cross bedded - a feature of the Parkgate Rock - differentially weathered and often quite coarse in texture.


Strongly cross bedded gritty sandstone in reused tracery

Heading back down towards the village, to further investigate the building stone in its vernacular architecture, I didn't see any follies or other structures in the grounds but the footbridge over Daking Brook, built in 1765, is Grade II Listed.

The Grade II Listed footbridge in Cawthorne Country Park

Friday, 5 July 2019

St. Mary's Church in Worsbrough


A detail of a Perpendicular Gothic style window

When arriving in Worsbrough Village to find St. Mary’s church closed, after a series of delays to my bus from Sheffield, I decided to just have a quick walk around the exterior to take a few record photographs and to come back another day.

A general view from the south-west

Starting with a general view taken from the south-west, my immediate impression was that this was yet another church that had been largely remodelled in the late 15th century. This was based on its transomed Perpendicular Gothic style windows to the south aisle and the bold castellated details, which can also be seen on the porch and tower.

A general view from the north-east

Walking clockwise around the church, the north aisle is of the same dimensions and has windows in the same style, as also in the south wall of the chancel. Looking closely at the ashlar masonry, although some of the yellow coloured sandstone is weathered at high level, the profiles are generally still very sharp.

Perpendicular Gothic style windows in the south aisle

According to Pevsner, the aisles were heightened in 1838 and the Historic England listing refers to the aisle being extensively remodelled during this restoration by J. P. Pritchett, therefore accounting for the relatively good condition of much of the masonry to the aisles.

The Norman window in the north chancel wall

The visible part of the exterior is the chancel, which is constructed in rubble masonry comprising generally flaggy sandstone with very high iron content, which is very similar to the general walling seen in much of the older vernacular architecture in the village. The round headed slit window in the north wall of the chancel is C12 and the east window is Decorated Gothic with reticulated tracery, which is typical of the early C14.

The east elevation of the chancel

Much of the chancel appears to be have been rebuilt, especially the quoins to the upper half and the well squared courses above the level of the apex of the arch contrast strongly with the masonry below. The parapets are of the same style as the adjoining aisles and it is therefore probable that the uppermost section was rebuilt during the restoration of 1838.

A general view from the south-east

The vestry, which is butted onto the south wall of the chancel, and the porch look to my eyes very similar in style and, with the interior of the latter being described by Pevsner as having a good Perpendicular roof, are probably of the late C15. The flat headed window, with its four centred arches to the lights, and the external door of the vestry has the characteristics of the Tudor period and, as I subsequently discovered in another visit, the door from the chancel is in a similar style.

Masonry to the vestry and chancel

The sandstone used in the mediaeval parts of the church, particularly in the Decorated Gothic tower, is very unusual and is unlike anything that I have seen before. Apart from its distinctly yellow colour, with cross bedding, it is the differential weathering of its large scale Liesegang rings which gives the sandstone used in St. Mary’s church its very distinctive character.

Liesegang rings in the sandstone masonry to the tower

The iron oxides in the rock are concentrated into nodules and dense bands that contrast strongly with the adjoining sandstone, where the natural cement seems to be depleted and is weathered at a much faster rate.

Ironstone nodules

The most extensive use of new masonry that I noticed is for the recent phase of restoration to the porch arch, using buff coloured medium grained sandstone, which contains some iron nodules but which is not really a good match to the original sandstone.

Stone replacement to the porch

Although the mediaeval stonework is in place highly weathered, replacement stone has been used sparingly, with much of it being left restored, including the dolomitic limestone headstops to the porch, or repaired with slips of stone bedded in mortar - in the Society for the Protection of Ancient Buildings (SPAB) style.

A repair using stone slips