The BB1 production site at Worgret on the outskirts of Wareham produced a Type 18 bowl from the fill of Kiln 161. The pottery assemblage from this feature amounted to some 239 sherds (2.358kg) and included the usual late Roman BB1 vessel types (2, 3, 20, 21, and 25) as well as a rim sherd from a Type 12 jar (see below) (Gerrard 2005a, 190). This collection of pottery does not represent the final firing of the kiln but instead material probably dumped into the kiln from other activities on the site. Crucially, Kiln 161 was cut through an ash layer that contained a coin of the House of Valentinian (AD 364-378) as well as OXRS and NFCC.
The coin would indicate that the Type 18 vessel could not have been deposited earlier than AD 364 and this is supported by the late Roman finewares. Nevertheless the excavators preferred to date the ash deposit to the 2nd or 3rd century on the basis of the BB1 it contained, although this BB1 is probably residual given the presence of the coin and late Roman finewares (Hearne and Smith 1991, 66).
The Bestwall Quarry excavations examined the largest number of BB1 kilns investigated to date. Here a number of Type 18 bowls (described as Class 2 Necked Bowls: Lyne 2012, 208-10) were recovered and considered to date c. 350/370-420+. Interestingly one example was decorated with a wavy line, rather than the more usual band of diagonal lines or obtuse lattice (Lyne 2012, fig. 145, 2/3). Associations with coins were limited but stratigraphically these vessels were recovered from the latest Roman deposits.