5.2 Plant macrofossil remains

E. Pearson, C. Keepax and P. Paradine

Blackstone Quarry was one of the first sites in Britain to make use of a flotation machine for extensive sampling of environmental remains. The plant remains were reported on by Keepax and Paradine (1977), and issues concerning possible modern contamination in the samples were also discussed in a published report by Keepax (1977). The data from the archive report were listed context by context (Keepax and Paradine 1977), and these data are further discussed here, where the results are now presented by area and context. Only charred remains have been included, as the uncharred remains are thought to be entirely modern contamination. Taxonomy of the plant remains listed in the archive report has been converted to follow Stace (1997) for this report. The barley grains listed as Hordeum polystichon in the archive report are assumed to be synonymous with Hordeum vulgare ssp. vulgare (6-row barley).

It was noted by Keepax and Paradine that many of the uncharred seeds had a relatively fresh appearance, and corresponded with species present in the modern-day environment. It was suggested that these were likely to be modern and intrusive (Keepax and Paradine 1977; Keepax 1977). This interpretation of uncharred seed assemblages from well-drained archaeological deposits, which are not anoxic, is readily accepted in most modern archaeobotanical reports. The most likely means of contamination of samples with modern plant material is movement through the light sandy soils by a combination of bioturbation (reworking of organic material in the soil by earthworms and insects) and by rainwater. Although it was thought that the sample collection and treatment had not caused contamination of the samples, the practice of air drying samples on polythene sheets prior to processing may have resulted in some contamination with airborne seeds. It was also suggested (Keepax 1977) that the charred seed remains might derive from stubble burning, which was very common in this part of the Severn valley at the time that the excavation was undertaken. No charred cereal chaff or straw has been identified, as would be expected if stubble burning waste had contaminated the Iron Age assemblages, although if this took place at some distance the site may have been contaminated with only light airborne seeds. Many of the charred seeds were small and light and could have been blown onto the site if burning had taken place at any time, but would have most likely presented a problem with contamination if this had occurred during the excavation. Ploughing of the site during the 19th century could also be an earlier source of contamination with burnt material, the small seeds being most likely to move down the profile. These facts point to the likelihood that at least some of the charred remains were modern (19th century or later), rather than contemporary with the Iron Age features. Wood charcoal (this included relatively large fragments in some contexts), however, is unlikely to have moved down the soil profile significantly.

5.2.1 Early prehistoric

Only single charred grains of oat (Avena sp.) and 6-row barley (Hordeum vulgare ssp. vulgare, or Hordeum polystichon in the archive report) were found in a gully (0149.1). These are the only remains likely to be contemporary with early prehistoric deposits (Table 19). Only occasional charred seeds, thought to be modern contaminants, were present in the other samples.

5.2.2 Iron Age

The results are summarised in Tables 20, 21, 22, 23, 24, 25, 26 and 27.

A low level of charred cereal remains was identified, which included wheat (Triticum sp.), barley (Hordeum vulgare), 6-row barley (Hordeum vulgare ssp. vulgare or Hordeum polystichon) and wild or cultivated oat (Avena sp.). The species of wheat was not stated in the original report, as the grains may not have been well preserved, but at this period they are most likely to be emmer or spelt wheat (Triticum dicoccum/spelta). These are more common in pit features, but in total they were found in only 15 contexts (Table 27). Charred fragments of hazelnut were found in 11 contexts, mostly in transects E and F. Seeds of weed species were, however, common and widely distributed across the site. Most of these species are also represented in the uncharred assemblages, which are not reported on here. A list comparing the species found charred and uncharred is included in the archive report (Keepax and Paradine 1977). The most common weed species found charred were thyme-leaved sandwort (Arenaria serpyllifolia), and ivy-leaved speedwell (Veronica hederifolia). The former is a plant common on open ground, particularly on sandy or limestone soils, and the latter a plant which would have grown on cultivated and open ground, hedgerows, walls and banks (Stace 1997). Several other species, mostly common on cultivated or disturbed ground were present in many samples, such as chickweed (Stellaria media), fat hen (Chenopodium album), corn spurrey (Spergula arvensis) and black bindweed (Fallopia convolvulus) among others.

5.2.3 Discussion

The cereal grain and fragments of hazelnut are most likely to be contemporary with the archaeological deposits. The low level of these remains suggests only small-scale processing of these food products, probably at a household level, with this waste being predominantly disposed of in pits. The combined presence of quernstones and a low density of charred cereal remains further suggests small-scale domestic crop processing and use. No further detailed interpretation of crop cultivation and processing regimes was possible from this evidence. There is some suggestion that a number of pits may have been used for grain storage (see Site Description), but the density of charred cereal remains is too low to confirm this. Nevertheless, cleaning of the pits, or even burning to cleanse the pits of pests and infestation of any kind could have resulted in the sparse remains. This sparse distribution of crop and food disposal is characteristic of this area, but also to some extent of farmsteads of this date generally in the county (Pearson 2001).


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