Monday, 17 October 2016

"Hooton Roberts Rock"


A detail of the "Hooton Roberts Rock" in situ

When I first visited Rotherham 35 years ago - as an undergraduate geologist - I became aware of a very distinctive variety of Mexborough Rock that is known as “Rotherham Red” sandstone.

A view of the landscape around Hooton Roberts

Especially when there are no crops growing, the red staining of the soil is obvious and, having since surveyed much of the geology of Rotherham and its historic buildings, I have always thought that the village of Hooton Roberts was built on or very near to this rock.

Red sandstones in Hooton Roberts

Continuing with my investigation of the mediaeval churches of Rotherham, when I planned my first visit to St. John the Baptist's church – whose oldest externally visible fabric is built out of very strongly coloured red sandstone - I was surprised to discover that it is shown on the British Geological Survey map viewer as a Pennine Upper Coal Measures Formation sandstone.

Yellow sandstone in boundary walls at Hooton Roberts and Thrybergh

Generally, this terminology is used to describe a rock formation that does not possess physical or palaeontological characteristics – or is not sufficiently extensive or prominent as a landform – to make it so distinctive from another sandstone to give it its own name.

Cleaned samples of "Rotherham Red" sandstone and "Dalton Rock"

Without having the resources of the British Geological Survey at your fingertips, and access to the vast collection of rocks and other information that has been acquired over the years – or full authority to enter upon land without objection – it is not easy to contest the findings of an institution that leads the world.

An investigation of the "Hooton Roberts Rock"

My copy of the 1989 reprint of the 1947 edition BGS memoir, which accompanies the Institute of Geological Sciences map - Barnsley (Sheet 87) enlarged to 1:50,000 scale and reprinted in 1976 - describes the sandstone underlying Hooton Roberts as either Dalton/Brierley/Great Houghton/Cadeby or Hooton Roberts Rock.

Bullrushes and other water loving plants growing on a spring line

Getting off the X78 bus at the first stop after Hooton Roberts, on the way to Conisbrough and Doncaster, I walked down the hill to the village and stopped several times to take photographs of known outcrops of Mexborough Rock, a spring line and various boundary walls - from which I collected a few samples of loose stone.

Foundations of the churchyard wall at Hooton Roberts

Finally arriving at St. John the Baptist's church, I examined the bedrock that forms the foundations of one of its boundary walls and - having had a conversation with an owner of one of the surrounding houses that is also built upon this very distinctive red sandstone - I decided that it was about time to invest in a new compass/clinometer.

Thursday, 13 October 2016

Sculpture & Monuments


St. Leonard's Cross

As with many of the mediaeval churches in South Yorkshire, St. Leonard's church has a highly weathered carved shaft of an ancient cross in its churchyard – made of Magnesian Limestone. Along with a niche in the south elevation of the chancel, it is the only example of this type of stone seen when walking around the exterior of the church.


Victorian head stops

Looking up to the top of the 15th century tower, gargoyles sprout from each corner and various head stops to various windows and the porch – added in the 19th century – provide some fine examples of stone carving in Carboniferous sandstone of unknown provenance.


A view of the nave from the chancel

Once inside the church, apart from the narrow sandstone arches arches to both the chancel and tower and a small section of walling left exposed in the plastered walls, it is the various monuments that are of most interest to the geologist.


Monuments carved in various decorative stones

Taking advantage of an offer to be guided around the interior of the church, after talking to various local residents when photographing the Buttercross in Thrybergh, I didn't have the time to examine any of them closely, but the monuments on the walls provide fine examples of various decorative stones that were favoured by memorial masons from the early 16th century onwards.


The chantry tomb of Sir Ralph Reresby

The highlight of this quick tour of yet another mediaeval church in South Yorkshire, which has a fascinating construction history, was the opportunity to see the chantry tomb of Sir Ralph Reresby and other defaced 14th century effigies – all of which are carved from Magnesian Limestone.


A 14th century effigy of a priest



Sunday, 9 October 2016

St. Leonard's Church


A general view of St. Leonard's church in Thrybergh

Approaching St. Leonard's church from its main entrance on the road from Thrybergh to Doncaster, the sandstone walling seen in boundary walls – with its distinctive yellow colour – has been quarried from the Dalton Rock; however, as previously seen in the boundary walling on the Doncaster road, some of the blocks have a reddish tinge similar to  “Rotherham Red” sandstone.


Colour variation in sandstone to the boundary walling

Looking at the church as a whole - essentially comprising an aisleless nave extended in the 12th century, a 14th century chancel, a 15th century tower and a 17th century porch - the principal building stone is yellow/buff coloured sandstone, which suggests that it has been mainly quarried from the Dalton Rock.


Evidence of extension, restoration and repair to the north elevation

A closer examination of the external fabric reveals considerable variation in the style of masonry between these different periods, with rubble walling and roughly shaped quoins used for the oldest parts of the structure and squared and coursed ashlar for later additions, as seen in other mediaeval churches in the region.


Various phases of restoration to the south elevation of the chancel

Various phases of restoration have taken place over the years - by Victorian architects in 1871 and 1874 and as part of later essential repairs to the relatively soft Dalton Rock - and this makes it difficult to analyse the construction history of St. Leonard's church in a brief visit.


A detail of the masonry on the north elevation of the nave

As with other churches in South Yorkshire that are considered to have been built around the time of the Norman conquest of Britain in 1066, the dating of the masonry has been the subject of debate. Sir Nikolaus Pevsner and English Heritage assign it to the Norman or overlap period, but the official church guide suggests a date of c.900 AD.


A blocked doorway with irregularly shaped quoins

The masonry to the jambs of the blocked door and the quoins to the south side of the nave is very irregular and uses very local stone, in a similar way to the oldest visible walls at St. John the Baptist's church in Wales.


A detail of quoins to the north elevation of the nave

Monday, 3 October 2016

Thrybergh


A view of Thrybergh from Dalton on the X78 bus

Continuing with my investigation of mediaeval churches that are set on or near to the outcrop of Rotherham Red sandstone, the X78 bus route to Thybergh follows its outcrop as far as Dalton and then crosses the Pennine Upper Coal Measures Formation sandstone (Dalton Rock); it then rises further on to the outlier of Permian dolomitic limestone, upon which St. Peter's church and Conisbrough Castle are set, before descending into the lowland landscape of Doncaster.


 An example of the use of local sandstone in Thrybergh

Although Thrybergh is mentioned in the Domesday Book, except for a handful of agricultural buildings constructed from the local Carboniferous sandstone, which is probably Dalton Rock, there is not much evidence of Thrybergh's ancient history to be seen from the bus - and it needs an exploration on foot to discover its oldest historic buildings and ancient monuments.


A general view of walling on the A630

Walking from Foster's garden centre to Rotherham Golf Club - formerly Thrybergh Park - long stretches of yellow Dalton sandstone walls form boundaries of various privately owned historic buildings, which usually provides a good indication of the underlying geology. 



An example of stone carving in Thrybergh

Along this very busy route from Sheffield to Doncaster, the salt that has been spread on the roads has taken its toll on the stone - the result of continuing cycles of wetting, freezing, drying and the recrystallisation of minerals contained in the groundwater. 


"Rotherham Red" sandstone and Dalton Rock

Hidden away in a triangular plot of land that was once the old village green, but is now a small housing estate, the old Buttercross is an excellent example of stone carving in this sandstone and, although it has been severely blackened by the pollution from the steel industry along the Don Valley, it has proved to be very durable.


The Buttercross in Thrybergh

Having discussed the various merits of the Buttercross, and whether it should be cleaned or not, with various people that live next to it, my investigation of Thrybergh continued with a guided tour of St. Leonard's church and - following directions that I had been given - I then set off to explore some of the high ground that lies on the south side of the Don Valley...


A view of the landscape around Thrybergh

Sunday, 2 October 2016

"Rotherham Red" Sandstone


Rotherham Red sandstone - from Treeton to Thrybergh

During my investigation of the mediaeval parish churches of Rotherham that are set on or near to the outcrop of the Mexborough Rock - named “Rotherham Red rock” by the Geological Survey in 1878 - I have surveyed the geology, landscapes and many historic stone buildings, from Rotherham town centre to its outlying villages.

The name comes from its marked red colour, which clearly distinguishes it from the buff sandstone of the same rock formation that then continues northwards from Hooton Roberts to Mexborough and further into Barnsley and West Yorkshire.


Rotherham Red sandstone from Treeton to Harthill

Looking at the Pennine Coal Measures Formation in Yorkshire as a whole, its strike essentially runs north to south, with the strata dipping to the east; however, in this part of South Yorkshire, the Don Monocline gives the landscape a very different character.

Whist waiting for responses from various keyholders of the mediaeval churches that I can easily visit from Treeton, I decided to make the most of a fine sunny day and explore the villages of Thrybergh and Hooton Roberts - on the X78 bus route from Rotherham to Doncaster.


Rotherham Red sandstone from Thrybergh to Mexborough

The current British Geological Survey map shows that both of these villages are set on a Pennine Upper Coal Measures Formation sandstone, previously described on the printed map as Dalton Rock, with the Ackworth Rock and Mexborough Rock to the north-west - the latter forming an escarpment overlooking the River Don.