St. Peter's Church in Letwell

 

St. Peter's church in Letwell

At the end of the 54th week since the COVID-19 Pandemic restrictions had been imposed in March 2020, there was still no sign of churches being opened for services or the general public and, as a result, I now needed to give a lot more thought to my trips for the coming year.

 

A map of the area to the south-east of Rotherham

 

As demonstrated with my exploration of the Pennine Upper Coal Measures Formation in the area between the Brecks and Herringthorpe in Rotherham, now that I had my Estwing hammer, I could better investigate the bedrock of the area instead of just looking at its building stones.

 

The route of the No. 20 bus

Using only public transport to explore South Yorkshire and the surrounding counties, I had got used to catching three buses to remote rural areas but, due to the cuts by First Mainline to the X54 bus service from Treeton, it was now more difficult to get to the south-eastern part of Rotherham. For my next day out, I firstly had to travel to Rotherham Interchange to catch the No. 19 bus to Dinnington – where I would then catch the infrequent TM Travel No. 20 bus to Letwell.

 

The TM Travel No. 20 bus timetable

Finally arriving in Letwell without any delays, which otherwise would have completely ruined my day, my plan was to have a quick look at Letwell and then walk to Maltby via Firbeck, Stone, Roche Abbey and Maltby Crags – a route where I knew would encounter some excellent geology and many stone built historic buildings.

 

The geology between Letwell and Maltby

Firstly, I made my way up to the west end of the village to take a quick look at St. Peter’s church, which still has its Perpendicular Gothic tower but with the rest of the building dating to 1869 - replacing an earlier structure of 1810 that had been burnt down.

 

Colour variation at St. Peter's church

Although the village is set on a small area of the Brotherton Formation (formerly known as the Upper Magnesian Limestone), this dolomitic limestone is unsuitable as a building stone and both the mediaeval and Victorian parts of the church are built with massive limestone from the Cadeby Formation; however, even at a distance, it can be seen that there is a very noticeable in colour between the stone of the tower and that used for the rest of the church.

 

The Perpendicular gothic tower

With the Roche Abbey quarries - a known supplier of stone for mediaeval churches in the area - being only a short distance away, it is very probable that stone for the mediaeval church came from one of these, but the provenance of the limestone for the C19 work is unknown.

 

Details of C19 masonry

I didn’t spend much time examining the fabric, but the limestone used for the C19 century elements has many characteristics that are not usually seen in the massive, oolitic and shelly beds that are quarried from the lowest part of the Cadeby Formation – the Wetherby Member.

 

'Shakes' in C19 masonry

 

The upper part, the Sprotbrough Member, is dolomitised to a greater extent, with a resultant obliteration of primary sedimentary structures and fossils. Diagenetic and tectonic features due to the depth of burial can also generate stylolites and fractures are commonly sealed with coarsely crystalline calcite, known to the quarryman as 'shakes'.

 

Textures seen in the C19 masonry

Differential weathering has highlighted these physical features, with some of the softer beds having been severely eroded, and there others for which I can not provide any obvious explanation – including a concentration of circular structures on bedding planes, which is also highlighted quite spectacularly on a gravestone.

 

A detail of a dolomitic limestone grave slab

Having made the effort to get to Letwell, I knocked at the doors of a few keyholders that were listed on the noticeboard inside the porch to see if I could obtain access to the interior, but with no success and, after taking a photo of the dark Shap granite used for a memorial, I left to explore the rest of the village.

A memorial made of dark Shap granite