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Stories and Stones: Crime and Punishment Walk
2:00 pm - 4:00 pm
Etnam Street Carpark, Leominster Herefordshire
Hidden History of Malvern College
Article by James Ferguson, a volunteer.
After Great Malvern Priory, three of the most important stone buildings in Malvern are to be found in Malvern College: The first, the Main Building, is the work of the architect, Charles Hansom, in 1862; the second is the Chapel, by Arthur Blomfield in 1896; and the third, the Memorial Library, by Aston Webb in 1922. Documentary sources from the College’s archives give us a valuable insight into the sources of the stone and the discussions leading to a choice of one stone over another.
The Main Building (1862) A letter from the architect, Charles Hansom, specifies local rubble stone from Cradley with Bath Stone dressings. This was the era before bulk transport of stone by rail, so a local stone for the bulk of the building was the obvious choice. The same materials were used for School House and the Porters Lodge nearby, as well as the walls bordering the site. Cradley Stone, quarried from the Ridgeway cross area, is common in and around Malvern and is a Lower Devonian green St Maughan’s formation sandstone.
The Chapel (1896) For Blomfield’s chapel, we have more archive material, though what is lacking are copies of letters sent by the school to the architect, so we have to deduce what went on from half the correspondence. The plan of Nov 5th 1895 was for the stone to be similar to that of the main building with Cradley sandstone for general exteriors and Jurassic oolitic limestone from Corsham for dressings and wall linings.
April 1896 sees the builders, Collins & Godfrey of Tewkesbury, submit a tender suggesting using Milton limestone (from Milton under Wychwood, Oxfordshire) for Corsham and either Bromsgrove sandstone or Hanborough Stone (also from Oxfordshire) for Cradley. In May the architect agrees that while Cradley Stone is basically cheaper, it is ultimately more expensive because of the problems in working it; he prefers Bromsgrove Stone to Hanborough. He also rejects Milton Stone on cost grounds at this stage. In August the contract is signed between the College and Collins & Godfrey, and Blomfield produces nineteen detailed handwritten pages for them. He specifies grey Bromsgrove sandstone for the exterior with Bath Stone where shown on the plan (since lost) and asks to be sent samples. There is also a reference to the external/internal stonework which will use Corsham Stone (presumably for ease of carving). Also, all the steps are to be of Portland Stone.
In Oct 1896, Blomfield writes that he does not like the Guiting Stone he has been sent (from Guiting Power, Oxfordshire) and now insists on Milton Stone because of the colour. The College seems to have been prepared to meet the extra cost, though it may be that the proximity of the Milton quarry to the railway line meant it was less expensive than they had first thought. There are no further references to stone types in the archive.
The Builder Magazine of April 30th 1898, 2 years after construction was completed, refers to Milton Stone with Bath Stone dressings. This, together with inspection of the building, suggests it is indeed of Milton Stone with Bath dressings and the steps are Portland Stone. There doesn’t appear to be any Bromsgrove Stone used. There is some Malvernian Stone in the wall to the west. The building was extended in 1908, to the south, using the same stone types.
The building was constructed at the height of the Arts and Crafts period, and there is much variety in the stone tracery of the windows. Inside, the nineteen-figure stone reredos (using Corsham Stone) is probably the best of its date anywhere. Sadly the intricate exterior pinnacles suffered severe crystallization damage and have been replaced by a composite, so that they are now all the same and have lost their former variety.
The Memorial Library (1922) By 1922, road transport was available so even more options were open to Aston Webb. He seems to have used a mixture of oolitic Cotswold stones that are browner than those from the Bath area; the building work was supervised by his son, Maurice, and he apparently paid less attention to detail than his father would have done. Even so the building was rated highly by Pevsner.
Another of the College’s First World War memorials is a bronze statue of St George which stands on a majestic plinth of Portland Stone. Unlike the other buildings this is not visible from College Road.
Altogether, the archives have given us a fascinating glimpse of the competing pressures on an architect in making a choice of stone. These clearly included locality, cost, durability and personal aesthetic preference. It is clear from this that a single archival source, particularly a specification, may not be representative of the final decisions taken. Furthermore, a wide range of stone, from near and far, could be available for a given building project by the late 19th century. It is no surprise then that the intricacies of stones’ origins take time and effort to unravel.
X-rays and Rainy Days
One of our big challenges on the Building Stones project is directly tracing a stone in a building to a quarry. Detailed fieldwork can be really effective for working out the range of rock types used and to give some idea of the areas these may have come from but, in general, for our project, has fallen short of providing a strong link to any one quarry. Much of this is down to the inherent variability of the typical rocks in this area. Both Old Red Sandstone and Silurian limestones – which together constitute almost all of the building stone in Herefordshire – can be highly variable within a single quarry. An additional problem in buildings is the lack of stratigraphic context once blocks are removed from a quarry and jumbled up in a building. This is particularly true of the Silurian rocks of the area. While a very detailed stratigraphy exists, this is largely based on pattern recognition and sparse fossil evidence; both of which are largely lacking in buildings. Looking purely at the lithology of a rock, it is often not clear whether it is from one formation or another. Diagnostic range fossils are rare, the main exception being Kirkidium knightii, a brachipod unique to the Aymestry Limestone which has been useful in confirming the use of this formation in several buildings.
Because of this I have been interested in exploring ways which may allow us to “fingerprint” stone from a given quarry or formation more uniquely. One such technique is analysis of thin sections of rock. By studying these under a polarised light microscope we can get useful information such as the porosity, cement and sediment mineralogy. Quite extensive use of this has been employed in Bromyard on samples kindly donated by homeowners, mostly derived from building work. This has given us some indication that there are useful variations in mineralogy which, in some cases, seem to be unique to a single quarry. However, there are significant drawbacks. Firstly we risk inaccuracies by characterising a quarry or building on the basis of only a few samples. Secondly any differences present are subtle and so, to properly understand, them requires “point counting”; an extremely laborious process whereby the mineral present at up to 500 points on a grid is identified and tallied to give a quantitative breakdown of the makeup of the rock. This takes up to 2 days per section. Lastly, inherent in this process is the removal of stone from a building. This limits the sites we can look at, by and large, to those which have current or recent building works.
As a result I have been exploring the possibility of using portable X-Ray Fluoroscopy to characterise stone buildings and quarries. In contrast to the mineralogical information yielded by thin section analysis, this gives us information about the chemistry of the rock which is ultimately related to the mineralogy as well as the diagenetic and weathering history of the rock. The machine is a handheld device with something of a Star Trek prop about it. Although surprisingly portable, it is rather heavy to hold at arm’s length for extended periods (as required if you don’t want to give yourself an imprudent dose of radiation). It works by firing X-rays at the sample. These excite electrons within the constituent atoms which, as they return to their natural energy state, release X-rays of their own or, in other words, fluoresce. The wavelengths of these X-rays are particular to each element and, by measuring the intensity of emitted rays at each wavelength, the instrument can determine the concentration of each in the sample.
With the instrument hired for a week I set about two main case studies: the first being Bromyard, where we could compare the results of thin section analysis and XRF for the same samples. The second was the Ludlow Breadwalk and Mortimer Forest sections which give a stratigraphically well-constrained section through the Silurian.
The results thus far are promising, with a few provisos. Both Bromyard and Ludlow seem to show some strong distinguishing features; in Bromyard, between samples from buildings in the town and buildings and quarries on the Bromyard Downs. This is interesting as it backs up the hypothesis on the basis of fieldwork that much of the stone in Bromyard was quarried within the town from several (now lost) quarries and possibly from the excavation of bedrock cellars too.
Around Ludlow, some of my attempts to get field data were stymied by poor weather. A big drawback with the instrument is that it is strongly affected by air and surface moisture. Heavy rain and fog on several field days along the Mortimer Forest trail rendered the data essentially useless which was very disappointing. Nonetheless, we had a good clear day to sample the Breadwalk Section which runs along the west bank of the Teme from Dinham Bridge to Ludford Corner. In addition, a large number of measurements were made on the curtain wall of Ludlow Castle in good conditions. This provides strong evidence that the castle is indeed built from the Lower Whitcliffe Beds which form the bluff on which it stands, rather than other formations which outcrop in various quarries across the river.
I am planning to do more work on this technique, particularly to see if it is possible to come up with a calibration to mitigate against the effects of water. Although as in all things with this project there is rarely a magic bullet, this technique does show a lot of promise as a cheap, quick and non-destructive way of comparing and linking stones. With sensible reservations, and an understanding that differences between formations will likely only ever be locally applicable, this could be a powerful addition to the Building Stones toolbox.
Where there’s a Wills there’s a Way
A brief biography of Professor L. J. Wills
by John Gerner, a volunteer.
Studying O level geology and inspired by David Thompson, later my PGCE tutor at Keele, I was fascinated by Professor Leonard J Wills’ Palaeogeography. Living close to Hill Top in Bromsgrove I was aware of Wills’ work there. Retirement and the Building Stones project have provided an opportunity to discover more.
In the early years of the 20th century Wills was collecting fossils with his father from the building stone quarries in what was then known as the Lower Keuper Sandstone now the Bromsgrove Sandstone Formation. While an undergraduate at King’s College Cambridge he continued to collect. In 1907 he graduated with a double first and an account of his finds was published in the Geological Magazine.
After graduation Wills was awarded the Harkness Research Scholarship and spent two years researching the geology and the fossils of the Triassic rocks of Worcestershire. His work led to the publication in 1910 of his paper on the Fossiliferous Lower Keuper Rocks of Worcestershire. Here he says of Hill Top “beginning on the south side of the hill these quarries belong, alternately, to Mr Willcox and to Mr Griffin”.
Wills discovered scorpion remains in a “greenish, very carbonaceous shale”. He was able to extract these from the matrix and mount them on glass slides. In 1946 he published a monograph on British Triassic Scorpions.
Production at the quarries declined during the 20’s and 30’s and in his monograph Wills comments “that for many years now the quarries have virtually ceased to be worked”.
In his 1976 IGS Report on The Trias of Worcestershire and Warwickshire Wills sums up Hill Top as “unique among British Triassic deposits in that it has yielded a fairly large fauna and flora” which have “an international correlation significance”.
Professor Wills’ connection with Hill Top spanned a remarkable eight decades and he considered his research on the quarries to be the beginning of his true education.
My own journey turned full circle when, trawling through the Wills archive at Birmingham University, I discovered that Thompson and Wills, at the time I was taking my O levels, were writing to each other about the Trias.
Today three of the four quarries have been infilled and built upon. The fourth is fenced off, overgrown and access is not permitted. A few remaining quarry faces can be viewed from the roadside in Forelands Grove. Fortuitously at the Bromsgrove Society summer school I ended up chatting to a resident who owns part of the quarry face and have been able to inspect it at close quarters.
Eye spy an Earthcache
Earthcache is the perfect activity to enjoy the great outdoors, see some interesting geology, and test your knowledge. Why not have a go this summer…
Go to www.earthcache.org
Written by Dave Stadley, a Building Stones Volunteer.
A couple of years ago, we reported on the publication of our first Earthcache, a variety of Geocache. January 2016 saw the publication of our 8th Earthcache; actually the 9th we’ve prepared but more of that later. To complete an Earthcache you must go to a specified location and search for something interesting. You must then answer a series of questions to show that you have found the features and “log” your visit.
As at January, 2016, our published caches have enjoyed approximately 3000 unique page visits, from not just the UK but numerous countries abroad including Denmark, Australia, India and Canada. Already there have been almost 200 physical visits to the locations nominated and in excess of 200 photographs uploaded to the webpages, conveying the enjoyment experienced by visitors to the caches. The logs left on the web pages are generally very complimentary too, as visitors, often local, express their surprise about features they’d not previously observed or appreciated.
The majority of these visits are likely to be by people with little or no prior interest in geology or of Earth Heritage Trust, hence the challenge (the conditions for being granted permission to log a ‘find’ on the geocaching website) is kept intentionally straightforward to maximise the inclusivity of the sites. In completing the caches, visitors are introduced to topics covering local geology, local quarries and the types of stone used in the construction of local buildings.
However, it is not always plain sailing when setting up the Earthcaches. Our first foray onto Bredon Hill, looking at ‘competent’ stones and the King & Queen stones, has been disrupted by the disappearance of the information sign used by the visitor to answer questions about the location, whilst our attempt to publish a cache on top of the hill met with the discovery that it fell within the boundary of an ancient monument and consequently, we are mandated to seek the permission of the landowners. These are both currently works in progress.
Looking forward, as we try to resolve the challenges on Bredon Hill, we have started planning our next pair of Earthcaches around the town of Kington. Here we are hoping to use one cache to highlight some of the natural features along the disused Tramway and the other to showcase some of the notable features of building stones used in the town. Together they should comprise a leisurely and enjoyable walk of a little over a mile.
Blackhouse Wood Geology Walk
10:00 am - 12:00 pm
Blackhouse Wood Reserve, Suckley Worcestershire
|NB: See bottom of page for full map and key to insets' geology. Go to map|
|Northwest Herefordshire||The Silurian limestone areas of the Ludlow Anticline, Mortimer Forest and Kington.|
|Upland Herefordshire||The St Maughans Formation hills of the Golden Valley and Bromyard Plateau, to the SE and NW of Hereford, respectively.|
|Central Herefordshire||The Raglan Mudstone lowland plains around Hereford and Leominster|
|South Herefordshire||The Brownstones plateau extending south from Hereford to the border with Wales and the Forest of Dean.|
|Malvern Hills||The Precambrian inlier of the Malvern Hills and adjacent Silurian outcrops.|
|Teme Valley||The Teme Valley between Knightwick and Stanford Bridge, spanning the Malvern fault zone and including Silurian, Devonian, Carboniferous and Triassic rocks brought together by faulting.|
|North Worcestershire||The Carboniferous and Triassic sandstones of the Severn Valley from Arley to Bewdley and the Triassic sandstone areas of Kidderminster, Stourport and Hartlebury. The same stones are also used in Worcester.|
|South Worcestershire||The Lias mudstone plains of south and central Worcestershire and the outliers of Jurassic oolite at Bredon Hill and Broadway.|
|Sandstone||Sandstone is a sedimentary rock made up of cemented sand sized grains of minerals. The most common constituent is quartz, followed by the mineral feldspar. Sandstones are the most common building materials in Herefordshire and Worcestershire and so make up a large number of buildings.|
|Limestone||Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Most limestone is composed of skeletal fragments of marine organisms such as coral, forams and molluscs.|
|Siltstone||Siltstone is a sedimentary rock with a finer grain size than sandstone. Individual grains are at the limit of what is visible with the naked eye. In several areas there is a continuum between limestone and siltstone depending on the amount of calcium carbonate in the rocks.|
|Igneous||Igneous rocks are those formed by the solidification of molten magma or lava. Examples include granite, basalt and diorite.|
|Metamorphic||Metamorphic rocks are formed by the alteration of igneous or sedimentary rocks by exposure to elevated temperatures and/or pressures. The change in conditions causes the minerals in the rock to change to new ones. Examples of metamorphic rocks include slate and marble.|
|Precambrian||4.6 billion - 541 million years old||more info->|
|Cambrian||541 - 485 million years old||more info->|
|Ordovician||485 - 443 million years old||more info->|
|Silurian||443 - 419 million years old||more info->|
|Devonian||419 - 359 million years old||more info->|
|Carboniferous||359 - 299 million years old||more info->|
|Permian||299 - 252 million years old||more info->|
|Triassic||252 - 201 million years old||more info->|
|Jurassic||201 - 145 million years old||more info->|
|Cretaceous||145 - 66 million years old||more info->|
|Cenozoic||66 - 0 million years old||more info->|
Building Stones Colloquium
10:00 am - 4:00 pm
Abbot’s Kitchen, Old Palace, Worcester