Tuesday, 29 March 2016

St. Helen's Church - The North Arcade



A general view of the north arcade


A close examination of the exterior of St. Helen’s church shows various styles of stone masonry, using both Rotherham Red sandstone and dolomitic limestone, which possibly dates as far back as the 12th century; the Norman style round arch to the south doorway provides the best evidence for its antiquity.

A detail of the pier and capital
Once inside the church, the north arcade is also seen to be Norman - 1175 to 1200, according to Sir Nikolaus Pevsner – with round, single stepped arches resting on piers with an octagonal profile and simply moulded capitals.

I had been inside the church only once before, to go up the tower, and I was therefore surprised to discover that the north arcade is constructed in limestone.

Looking since at other mediaeval churches that are built on, or very near to the outcrop of the Rotherham Red sandstone, dolomitic limestone has also been extensively used in various Norman style arcades and doorways.  

The Normans had demonstrated that they were master builders in stone – at Conisbrough Castle and Roche Abbey – and they knew perfectly well that Rotherham Red sandstone was not a first class building material. 

Although they probably didn’t appreciate the shakes and vents that are found in the Magnesian Limestone - which is quite unlike Caen Stone - it was good enough for the solid structural and simple decorative elements that are seen in St. Helen's church.


A view of the north arcade through the south arcade

Saturday, 26 March 2016

The National Coal Mining Museum


A general view

Having taken advantage of the winter months to undertake a detailed examination of the stonework at St. Helen’s church - to both the exterior and interior - the first spring like day coincided with a trip to the National Coal Mining Museum, with the Sheffield U3A Geology Group.


A general view

With the deep coal mining industry in the UK being recently consigned to history, and living in an old village that played its full part in the "Battle of Orgreave", I really appreciated the opportunity to get a small insight into an industry that once powered the economy of this country.


A museum display

As a geologist, and with interests in many things related to stone, I have been inside a few caves, but I had never been down a coal mine before. About 20 of us paid for a special tour of the drift – a small steeply inclined tunnel complete with conveyor belts and rail tracks once used to move the coal from deeper levels – and then joined the free general tour.


An old locomotive

There is not much rock to see - apart from thick seams of coal that form part of reconstructed scenes and various exposures of shale and flowstone - but I was particularly impressed by the construction of the tunnels themselves, including the related plant and machinery, and other services that were needed before a single bit of coal could be extracted.


The Kellingley Colliery Memorial

I find it hard to imagine what this industry must have been like, with thousands of miles of similar structures running all through the Coal Measures strata of the British Islands. As a field trip leader - along with various other geological sites and historic monuments - I would certainly include the National Coal Mining Museum on my itinerary for any group of Geotourists who might want to see this part of England.


A piece of coal

Thursday, 24 March 2016

Restoration & Conservation



A failed repair

As a geologist, whose professional work occasionally drifts into archaeology, an investigation of the stonework at St. Helen’s church has provided me with a good insight into the difficulties of assigning a date to this and many others that have a Saxon origin.


A fading memorial

Using the various published sources of information available to me - and my own observations - I now have a much better understanding of the various architectural styles that have been used from the 12th to the 21st century.


Severe cavernous decay

Looking at the overall condition of St. Helen’s church from the exterior, despite being undermined by Treeton’s own colliery and its fabric being subjected to the very dirty and sulphurous emissions from the Orgreave Coking Plant – both of which have now been landscaped and covered in houses – it has stood the test of time very well.

A detail of the porch
Although a close inspection of the tower is necessary before any further conclusions can be made, the scientific reasoning behind the choice of similar dolomitic limestone to build the English Houses of Parliament – based on its resistance to acid attack – appears to be borne out here.

Used in the plinth course, windows and doors, the limestone has been weathered and eroded away to varying degrees, exposing some of the natural characteristics of this particular stone - which make it completely unsuitable for carving in the Perpendicular Gothic style.

Vents, shakes and hard concretion like structures can also be seen.

Forming the highest point in the old village, with the prevailing south-westerly wind and rain eroding the Rotherham Red sandstone away, the micro-climate of Treeton has also further contributed to the degradation of its fabric - as seen all around the church.


Various materials used for restoration & conservation
 

Tuesday, 22 March 2016

The Nave



A general view of the nave


The only part of the nave that can still be seen from the outside of St. Helen’s church is on the west elevation of the building – set between the old tower and the modern vestry.


Views of the nave at different times of the day

Reading various documentary sources, it is generally agreed that the date of the nave is 15th century; furthermore, the west elevation appears to have been built in one phase, using long, large blocks of Rotherham Red sandstone - as previously seen in the clerestory.


Weathering details

Compared to the masonry of the tower, into which it is tied by 3 large blocks of similar sandstone, the courses are regular and finely tooled. Looking at the castellated parapets, they also appear to be consistent in style with the other roof level details seen around the church. 


A severely weathered head stop

A particularly unusual feature of the nave is its west door, which seems to run against all good principles of architectural design and - looking closely - this doorway is also constructed in a sandstone not seen before in the fabric of St. Helen's church.


An unknown sandstone