Kiln — pottery in Highhays

Archaeological monitoring of groundworks for part of the MacDonagh Junction Shopping Centre development was carried out by Emma Devine and Cóilín Ó Drisceoil in 2006 (Devine and Ó Drisceoil 2008, unpublished; Devine and Ó Drisceoil 2009). A medieval pottery production centre was excavated (06E0122) at Highhays, Dublin Road, Kilkenny. The site (60m E-W, 25m N-S) lay within a previously unknown medieval suburb situated 200m outside (NE of) the town ditch of the ward of St. John’s Kilkenny and immediately adjacent to the chief Fair Green of the medieval town at John's Green. The production centre comprised of a pottery kiln, the foundations for workshops and stores, extraction pits, waster pits, a drying-kiln, a clay-store and fuel stands, as well as cess pits and refuse pits that were probably used by the potters. The kiln site was situated 150m to the W of a contemporary corn drying-kiln (KK019-026213-), oven and other features belonging to the same suburban settlement. The pottery kiln lay at the NW end of the excavation area, on the NE side of the Dublin Road near the former entrance to MacDonagh Railway Station, on flat ground (50m OD) at the base of a gravel ridge that rose to a height of c. 5m behind it to the E. About two-thirds of the original plan of the kiln survived, the remainder had been lost to a modern pipe-trench which ran longitudinally through it. Ground lowering for the widening of the Dublin Road in 1818 had also removed all but the deepest 0.2m of the kiln. The kiln was a NE-SE orientated double-flued, single-chambered updraught structure with adjacent stoke-pits (Musty Type 2C), with maximum excavated dimensions of 3.45m x 0.55m. The elongated oval central firing chamber (L 1.3m; Wth 0.55m; D 0.2m) had been sunk into the sandy clay subsoil. Its original width was probably in the region of 1.1m. The floor of the chamber was flat and its base, sides and flues were fire-scorched to a thickness of 0.04-0.06m. The kiln chamber had been largely cleared after the final firing of the kiln but it was possible to ascertain that fire-bars had formed a raised floor within it. There was no evidence that the chamber was lined in any way but the remains of a rectangular stone pedestal occupied the middle of the ware chamber. Archaeomagnetic dating of the rubified sides of the kiln chamber produced a date of 1325-1375, at 95% confidence, with the most likely date of its final firing estimated to have occurred in AD 1336. A radiocarbon date of cal. AD 1305-1400 from the kiln's fuel-load correlates well with the archaeomagnetic date. Forty-two sherds of Highhays ware pottery and 160 ridge tile fragments (HHTT 3 fabric) were recovered from deposits within the kiln. Kiln damage and pot stacking marks on some of the ridge tiles suggest they formed part of the final load within the kiln's firing chamber. To the NE and 20m uphill from the pottery kiln, in the highest (52.8m OD) and driest part of the site, was a rectangular E-W orientated, open-sided, stone-footed building (Structure A) with excavated dimensions of 9.5m x 5.8m. Its S side had been removed by a 19th century railway wall but if the typical width:length ratio of 1:2 was employed its original length was probably in the region of c.11.6m. The structure was likely used for drying the newly-thrown pots, with the wide entrance acting to provide good circulation of air. Fragments of a stone shed (Structure B) were situated 2m to the S of Structure A. Its walls were abutted by dumps of unprocessed clay and it can probably be interpreted as a clay store. All that remained of it was a clay-bonded rubble wall (L 2.7m; T 0.7m) with a fragment of a SW return, suggesting it was originally quite a small building. Foundation slots for earth-fast sills defined the ephemeral remains of a rectangular timber-framed building (Structure C) (excavated dims. 4.5m x 4.05m) that was situated 8.5m to the N of Structure A. A later, probably 15th-16th century, boundary ditch had cut through its N side and its W extent had been removed by a modern pipe trench, making it difficult to reconstruct its original length. Three cess-pits were excavated adjacent to Structure C. At 1.7m the deepest of the three had indentations on either side of its lip that probably originally held a timber latrine. Its primary fill contained a large assemblage of palaeobotanical material, including charcoals of birch, hazel, ash and oak, and stones of sloe, grains of free-threshing wheat, indeterminate cereals and grasses. Insect puparia, typical of latrine deposits, were also noted. A keyhole-shaped drying oven (L 3m) was sited 14m NE of the pottery kiln. It comprised an E-W aligned subsoil-cut circular drying-chamber, from which a stone flue (L 2.1m; Wth 0.7m; D 0.2m) projected. The flue was lined with a stone wall (T 0.25m). Although drying-kilns were primarily used to harden damp grain prior to its storage or grinding, it is likely, given its location within the pottery that it also had a role in the ceramic production process. Seventy-eight pits were recorded in the environs of the pottery kiln. These were clustered in two main groups, one in the lower ground to the S of the pottery kiln and the other to the N of Structure A. The majority, 62 in number, of the excavated pits were quite irregular (sub-circular/sub-rectangular) in shape and can be best interpreted as quarries for the underlying boulder clay and sand and gravel substrata for use in the ceramic production process. It is also possible that some of the pits were used for poddling (levigation) to allow the ‘raw’ clay to sit in water and settle in order to sort the larger particles and stones from the finer clays. The collection of rain/surface water seems to have been relied upon for the provision of water in the production process and there were a number of deep, silt-filled cylindrical pits excavated in the low-lying W side of the site that may have been dug specifically for this purpose. Three of the pits were capped with dumps of stone that formed circular, well-drained pads that were probably created to provide dry areas for the storage of wood which was used during the firing of its kilns. Over six thousand (6163) sherds of 'Highhays Ware' pottery were recovered and their analysis indicates that manufacturing focused on hand-built and wheel-made, round-bodied, pear shaped and possibly baluster glazed jugs, globular hand-built and wheel-thrown jars and cooking pots, money boxes and ridge tiles. An ICP-AES study suggests it was clays from the Castlecomer area, 18km N of Kilkenny, that provided the main source of raw clays for the Highhays potter(s). A second source of clay was situated at Sandfordscourt, 6km NE of Kilkenny. Small quantities of Kilkenny-type cooking ware, Leinster Cooking ware and imported Saintonge green-glazed and Flemish red-ware were also recovered. The site appears to have been abandoned before or perhaps as a result of, the Black Death, which decimated Kilkenny in 1348-9. It is likely that the continuation of the site remains in situ outside the excavated area to the SW and NW. See attached photograph: KK019-026211-_01 taken by Cóilín Ó Drisceoil Compiled by: Cóilín Ó Drisceoil Date of upload: 29 March 2020