Two mortarium fabrics which are related in source area, general appearance, and probably overlapping in date, are included under this umbrella. Our sample of GLG OX differs somewhat from the standard CNG OX fabric, but vessels not included in the collection, one of which was examined in thin section, are virtually identical to CNG OX although still having the calcareous clay associated with GLG OX. It is likely that they are products of two different workshops active in the same area.
Our samples are typically dull pink or pink-brown (5YR 6/4-7/4, 7.5YR 7/4), often with slightly paler surfaces. Hartley (pers comm) notes two different colour variants, one which is pink-brown, as our samples, and a second which is a brown-cream. It is hard, slightly powdery to the touch and has a smooth fracture through which coarse inclusions protrude. Concentric scoring is visible on the interior from the trituration grits, but the flange is never deliberately gritted, nor scored, and can be very smooth.The vessels belong to a restricted form (eg Hartley 1991a,TC 8–18, figs 78–80), which is never stamped.
The clay matrix is usually fine, clean and micaceous, containing primarily gold mica. In the fresh fracture a sparse scatter of quite coarse ill-sorted inclusions, measuring between c 1.0–2.5mm, is visible: quartz (sometimes angular), angular feldspar (sometimes decomposed), frequently rounded and both light-coloured and redder rock fragments, and fewer accessory minerals, rarely to 1.0mm, can all be identified. Of these inclusions, feldspar and light-coloured rocks are the most distinctive. Silt-sized iron-rich inclusions are also present. Trituration grits present on the lower part of the vessel bottom are well sorted (to 4.5mm) and, like the break, varying in composition, consisting of common quartz and feldspar (sometimes decomposed) and sparse rocks. Large (c 1.0mm) flakes of gold mica are often visible on the interior surface.
This sample comprises a clay matrix with low birefringence, containing common flakes of mica, up to 0.06mm, and sparse subangular grains of quartz silt. Sparse subangular granitic rock fragments up to 1.5mm, consisting of quartz and feldspar with or without biotite and disaggregated monomineralic grains of these minerals, are the main aplastic components.
The petrology of this fabric conforms with the Massif Central region, and this has been proposed as a likely source area on petrological grounds (Williams 1993, 425). Tyers (1996, 130–1) has compared the British fabric with one from Vienne, an area of pottery production, and has suggested that the Vienne/Lyon area could be the source, which would be in keeping with the petrological evidence.
Bath Archaeological Trust; Museum of London
Roman Baths Museum, Bath; Royal Albert Memorial Museum, Exeter; City Museum and Art Gallery, Gloucester; Museum of London
Davies, B J, Richardson, B, & Tomber, R S, 1994 The archaeology of Roman London 5. A dated corpus of early Roman pottery from the City of London, CBA Res Rep 98
Hartley, K F, 1985a The mortaria, in Kingsholm. Excavations at Kingsholm Close and other sites with a discussion of the archaeology of the area (H R Hurst), Gloucester Archaeol Rep 1, 55–93
Hartley, K F, 1991a Mortaria, in Roman finds from Exeter (N Holbrook & P T Bidwell), Exeter Archaeol Rep 4, 189–215
Hartley, K F, 1993b Mortaria [from the fortress], in Report on the excavations at Usk 1965–1976. The Roman pottery (ed W H Manning), 68–72
Tyers, P A, 1996 Roman pottery in Britain
Williams, D F, 1993 The petrology of mortarium fabrics 5, 6, 11 and 13, in Report on the excavations at Usk 1965–1976. The Roman pottery (ed W H Manning), 424–5