Internet Archaeol. 17. Willis. Longevity of Use and Residuality

5.7.4 Samian: Longevity of use and residuality

The database is a potentially helpful tool in this respect in so far as it enables the 'life-span' of each specific type to be identified (cf. Willis 1997b, Section 5.2.3). It can also be used to plot the relative frequency of a type over time, as with the case studies outlined in Section 5.4; the resulting curve will in most cases approximate to a normal distribution curve. The latter part of each profile of relative frequency will be 'tail' of examples occurring through later site sequences. This tail will be composed of residual items and/or sherds from vessels that had survived in use beyond what might be expected as their normal date range and are freshly lost/discarded material within layers that date to after the normal period of deposition of the type. Both possibilities are, of course, of archaeological interest. To what extent a 'thick tail' particularly in the decades following the end date of the normal date range represent residual items or curated vessels will be unclear at this level (cf. Section 5.8) but is probably a function of continued use. Ultimately such questions are probably best resolved in qualitative review of sherd condition, including review of average sherd weight.

With samian the 'hangover' of apparently earlier material in later deposits can be acute. At sites, for instance, with occupation of the second half of the first century AD in receipt of good supplies of samian at that time, residuality of this first century (South Gaulish) samian in second century contexts can be high, particularly during the Hadrianic to early Antonine period. In the case of the Baromix site, Alcester (1969), from Phase D, dated to c. AD 125-140/150, as many as c. 93 South Gaulish samian vessels are represented (normally associated with a date of c. AD 40-110), with 31 examples of the cup Drag. 27, though only 10 Central Gaulish vessels (of second century date) are recorded from this phase, with no Drag. 27s (Booth and Evans 2001; Ward 2001, 38-9).

At the Rosemary Lane Carpark site, Canterbury, pit fill context 279 ('Cante3'), dating to the Hadrianic-early Antonine period, shows a similar phenomenon. Within, more South Gaulish La Graufesenque vessels, which should have been passing out of use c. AD 100-120 if not before, were represented than Central Gaulish samian vessels, which will have been contemporary with the filling of the feature (the figures being 13:9 respectively). Well 101 at the same site ('Cante4'), dating to the later second century AD, again has a high proportion of La Graufesenque vessels, but in this instance a range of Central and East Gaulish vessels are present, contemporary with the filling of the feature.

Levels of older material in later horizons vary, of course, specific case by case. Whilst high levels of first century samian in excavated deposits of second century date may not be atypical and unrepresentative of the type of pottery samples often collected during excavations (cf. Section 5.8), the residual or curated content blurs the contemporary (ie. second century) pattern of samian supply and consumption which we may be primarily interested in. Site samian groups with markedly high (evidently) residual content present have not been recorded in the project database.

Of interest is the fact that particular samian types have thicker 'life-span' tails than others suggesting they are either associated with a high degree of residuality or, more likely, a proportion of the class of vessel was still in use and being deposited in archaeological deposits beyond its normal date-range. It would seem that decorated vessels in particular were curated more so than plain forms. A high number of South Gaulish Drag. 37 bowls, for instance, occur in horizons dating to the first half of the second century in London, which is part of a wider pattern (cf. Willis 1998a, Illus. 13). Curation of Lezoux samian into the third century is attested (cf. Section 5.8).

5.7.5 Further aspects

One method of ascertaining levels of residuality within a group / site sample might be thought to be via identifying all samian types present and establishing their normal associated date-range. A proportion of vessels may have date ranges which precede and do not overlap, the ascribed date of deposition of the group. These pieces might be considered the residual element. However, there are two difficulties. The 'date-range' of the samian types is an aggregate of the incidence of other examples of the type: examples appearing in specific site groups might in fact be 'early' or 'late' outliers of the range. Secondly, the date ascribed to a context or site phase is likely to be the outcome of an equation, or 'weighing', of indicators of date, amongst which one element will be the date of the samian.

Consideration of the proportions of samian present in late Roman phases (c. AD 275-400) may be beneficial. This is of potential value in our attempts to better understand residuality since all samian in deposits assigned to this date range should be residual (or exceptionally well curated). Study of the percentages of samian present within deposits of such date should shed light upon trends in residuality. A further area of interest is the occurrence of samian as grave goods, for there are many instances of what seem to be 'old' samian vessels present in graves (cf. Section 9; Wallace forthcoming).

Via the methods noted above samian might be used to identify general degrees of residuality or longevity in a manner that has not previously been possible within pottery analysis. Caution though is necessary as the nature of the data is complex. Levels of residual pottery, including samian, in site contexts are not predictable.