On a cold, bright Saturday morning we assembled in the medieval heart of Taunton, for a lesson on the townscape, to be given by the doyen of building stones, Eric Robinson. He explained that the oldest (medieval) buildings were of stone derived locally, or brought by river from the countryside immediately around. This is shown in Eric's map (Figure 1) which also shows many of the localities and routes to be mentioned in this article. When canals were built in the early 18thC, stone could be brought from further afield. The arrival of Brunel's Great Western Railway in 1842 meant that Bath stone (the railway tunnel at Box near Corsham had started in clay-rich limestone but went into the purer Bath stone), Cornish and Scottish granites could be imported. This pattern of availability of stone with time is repeated in many West Country towns.

We began with the remains of Taunton Castle, now just a wall of grey-green sandstone, showing bedding and some small pebbles. This is North Curry sandstone, from a low escarpment to the East of Taunton (see map Figure 1). This sandstone lies above the Triassic and itself is capped by chert. The wall shows that the rock has porosity, as the blocks are often lichen-covered. The castle became a hotel, and in the 18thC a ceremonial gateway was built, with squared blocks containing oyster shells. The golden-brown colour of this Ham Hill stone, and the way it weathers make it recognisable elsewhere. (Eric also called this stone 'Hugh Prudden-ite', in an affectionate recognition of the work that Hugh has done on the Ham Hill quarry). Ham Hill stone is Upper Lias in age & was brought to Taunton by small barges down the River Parrett. Across the courtyard, the Museum is a relatively new building (1931) but with Ham Hill stone quoins to the windows and door. As there were no Ham Hill quarries open at that time, the stone has all been reused from other buildings. The blocks of the building façade are a variety of pebbly red sandstones (Trias) and blue/yellow Lias. There were also examples of Devonian sandstone with pebbles from the Quantocks, with vein quartz. Outside the museum is a statue of Field Marshal Harding of Petherton, on a Portland stone plinth: an oolithic limestone with shell fragments of oysters, pointing to clear shallow water deposition.

Emerging through an archway from the courtyard, the paving was grey micaceous sandstone with clear ripple marks characteristic of Pennant sandstone, Culm facies, from North Devon.

We crossed to the Winchester Arms (but not inside, unfortunately) which is made of Purbeck limestone (not marble) and on to the Moat House, built of muddy, Culm facies Carboniferous limestone from Westleigh Quarry, south of Wellington. This building is an Edwardian extension to the medieval Old Grammar School, which is also of flaggy Westleigh limestone with Ham Hill stone windows. The old Art School opposite is a handsome building of Bath stone, with a commemorative granite block, originally polished & inscribed with a dedication that is now unreadable. Eric theorised that the inscription had been removed by pressure washing, but I personally doubt that and believe that the inscription has been deliberately removed by hammering. Perhaps we should investigate this further.

After a quick lunch (to thaw out), we started on the more modern buildings in the shopping area. We noted that the buttress at Castle Bow had some small granite blocks, but artificial quoins were made to look like Bath stone. Adjacent to the buttress, the retailer Next has real Bath stone, with small channels & burrows visible. Moving on to Burtons (formerly Montague Burton - 'the window to watch') we found commemorative stones dated 1929 and a frontage of larvikite, named after the small town at the head of Oslo fjord, Larvik, that is the source of this blue-grey syenite (a coars-grained igneous rock composed mostly of feldspar with very little free quartz). The noticeable feature is the shimmering large feldspars, showing 'Schiller structures'. The rock can be obtained as 'blue pearl' and 'grey pearl'.

Bath Stone

The Post Office, a building dating to 1914-18, is made of Portland stone that is displaying signs of weathering. This is because SO2 in the atmosphere combines with the CaCO3 of the limestone to give CaSO4 - gypsum.

We then found a building sporting a façade of 'Baltic brown', a Precambrian rapikivi granite from the Finland/Russian border. It has an 'orbicular' structure, the origin of which geologists have puzzled over for decades (similar orbicular structures have been seen in the granite rose in Brittany, and 'Joe Jennings granites' in Finistère). Bob Jay has also sought out this granite at a bar in Paddington station (location courtesy of Richard Fortey) & at the end of the trip the group found it as a superb surface in a cafe in Taunton.

Red Sandstone

The façade of Whittards is beautiful pink Devonian Torquay limestone that Eric declared would look so much better if they bothered to polish it a little. Another shop had the polished black South African/Indian mineralised gabbro that is now sold as 'black granite' for kitchen worktops. Then we moved into Hammet Street, flanked by beautiful Georgian brick buildings with slate window sills; the kerbstones are Pennant Sandstone and the alleyways off the street have small slag pavings and some large blue limestone (Lias) flags. We reached St Mary Magdalene Church, which has a Ham Hill stone façade and pillars; the sides, however, are a patchwork of stones. Some are from Hestercombe in Somerset, which has been a source of diorite since the 14thC, from a dyke that is Late Carboniferous - early Permian. The rock has a green tinge because it contains chlorite. The other major component of the church is blocks of red sandstone pebble beds. At this point the committee thanked Eric and excused themselves to have a quick meeting, and cup of tea to warm up! We are all guilty of taking little notice of the buildings around us and the people of Taunton are lucky to have so many natural stones in their town centre (and lots of independent traders). It was an excellent trip on a wintry day.

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Words & Photos: Dee Edwards

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