Mortaria are the only form type in this fabric known to have been made at Catterick. Those whose distribution is certain are stamped 2nd century mortaria, which usually have a white or cream slip, but some may be self-coloured and one is known with a red slip. Since the red-slipped fabric is so unusual, it has been included in this group.
The rim forms and fabric are similar to those produced at Cantley and Swanpool during the 3rd and 4th centuries (although not on the two photographed sherds presented here), but the Catterick fabric is sometimes paler. Additionally, Catterick potters sometimes delimited the slip (extending onto the underside of the rim for about 5.0mm and ending in a straight slip), and smoothed and polished the exterior, techniques not seen at Cantley (K Hartley, pers comm).
Our samples are hard and orange-brown (2.5YR 6/8) with a brown (2.5YR 5/4) or pale orange (5YR 7/6) core. On one, surfaces are covered with a buff/cream (10YR 8/3–8/4, 7.5YR 8/2) slip, while the other is atypical with an external orange-brown (2.5YR 5/8) slip. The fracture is irregular, the feel smooth and evidence of knife trimming is visible around the exterior of the base. Mortaria with bifurcated hammerhead rims were produced.
This fabric has well-sorted inclusions, with only quartz and iron-rich grains routinely present. Quartz is common with two variants represented by our two samples. The first contains quartz grains averaging 0.1–0.3mm (Plate 163a), while in the second, they commonly occur up to 0.5mm, with outliers up to 0.8mm. The remaining inclusions are sparse and may measure up to 1.0–2.0mm in size: matrix-coloured iron-rich grains and, less frequently, pale-coloured clay pellets and rounded grains of slag – presumably strays from the trituration grits – can be identified.
Hartley (pers comm) notes that the 2nd century mortaria have either mixed trituration grit of flint, quartz and red-brown inclusions, or are restricted to quartz. Those made in the 3rd and 4th centuries in this fabric were in the Cantley/Swanpool tradition, making distinction between the three difficult. On our samples trituration grits comprise abundant well-sorted angular and subrounded grains of black slag, averaging 2.0mm on one sample and 4.0mm on the second, and therefore belong to the 3rd or 4th century.
A fine clay containing sparse silt and common ill-sorted inclusions can be seen. Inclusions are primarily monocrystalline quartz, but polycrystalline quartz, fine-grained sandstone, flint and rare feldspar, measuring 0.1–0.5mm, are also present. Opaques, in a similar size range or smaller, are sparse to common, while muscovite mica is sparse. Trituration grits of slag range between 1.0–3.0mm.
No kilns are known for this type and the source is proposed on account of their abundance at Catterick, with lesser amounts, probably from the same workshops, known at Piercebridge and Binchester (K Hartley, pers comm). A kiln producing black-burnished style wares is however known from the area (Busby et al 1996).
Yorkshire Museum, York
Busby, P A, Evans, J, Huntley, J P, & Wilson, P R, 1996 A pottery kiln at Catterick, Britannia 27, 283–97
Wilson, P R 2002 Cataractonium: Roman Catterick and its hinterland. Excavations and research 1958–1997, CBA Res Rep 128 (1)