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The following proposals are based on the analysis of the pottery from excavations undertaken in 1995-98, and a brief review of pottery excavated in 1999. It should be noted that these comments are made in the light of pottery excavated from Nosterfield during 1995-99 and they may need to be modified in respect of different excavated contexts, ceramics of a different chronological horizon, or other circumstances surrounding the excavations at Nosterfield. These comments are specific to the Nosterfield assemblage and do not apply to ceramics of any period excavated from any other site.
Analysis of the pottery excavated so far suggests that the condition of the material varies according to the chronology and type of pottery rather than as a result of depositional and post-depositional factors. The single most important variable is probably the temperature to which the ceramic has been fired.
In general terms of durability the later Neolithic Peterborough Ware is probably the most resilient, followed by the earlier and middle Neolithic Grimston Ware, with later Neolithic Grooved Ware being the least durable fabric. This information is of little use, however, to the non-specialist excavator, particularly if the ceramic material is caked in soil. Accordingly, the following guidelines are put forward to assist in the processing of the pottery in a way which should enable the material to be maintained for more detailed analysis by a specialist.
Keep the pottery as far as possible in the same condition of dampness as excavated - all pottery in the soil will retain some water except in drought and heatwave conditions. Do not leave potsherds on the surface pending excavation, photography, or the end of lunchbreaks, as they will dry out rapidly, with the danger of cracking, or may be the subject of weathering, damage, or loss.
Excavated sheds may be considered in two groups:
Group 1
Single sheds or groups of sherds which retain their structural strength (i.e. they do not crumble when lifted).
If the pottery is sufficiently resilient and the soil sufficiently dry remove
surplus soil by brushing lightly with a hogs hair shaving brush. Avoid puddling
damp soil onto the sherd and avoid scraping or damaging the surfaces.
Place sherds in sealable plastic boxes on a layer of tissue paper. Good quality
kitchen towel will do at this stage. If the soil (and the pottery) is wet
or moderately damp, leave the tissue dry. If the soil and the pottery is damp
slightly dampen the tissue with clean water from a small plant spray before
placing the pottery in the box. If the soil and the pottery is dry leave the
tissue dry.
Seal the box carefully. If pottery from a single context fills more than one box it is helpful to mark it '1 of 2' as appropriate.
Keep in cool conditions (a domestic fridge is best).
Group 2
Single or grouped sherds which are unstable (i.e. break up when lifted).
Consider the value of lifting the pottery with the surrounding soil. Remember that removal simply moves the problem from the field to the laboratory, but it does offer the opportunity to employ laboratory techniques in due course. Large areas of vessels which exhibit details of design or form are likely to be of most interest. There are, of course, exceptions to this rule - if the pottery looks different from other material recovered from the site it is worth taking care to retrieve it. If the material is much like better preserved pieces proceed as for Group 1 sherds. Otberwise:
Prepare a bed of slightly damp kitchen paper towel in an appropriately sized sealable plastic container and use a trowel or spade to lift the sherds and surrounding soil matrix onto the paper. Place further slightly damp paper above the pottery and seal. Take care not to over dampen the paper; the ideal is to maintain the existing state of the fabric, not to dampen it further.
Keep in cool conditions (a domestic fridge is best).
As soon after excavation as possible and in any case within six weeks, clean the pottery. Whatever you do some pieces of pottery will break up. Not all conservators will agree with the methods suggested here, but they have been discussed and justified with an archaeological conservator. Unless obviously resilient, sherds below 4 square cm in area can be left as they are, while all sherds below 1 square cm in area should be left untreated.
Group 1
Single sheds or groups of sherds which retain their structural strength (i.e. they do not crumble when lifted). These should be cleaned in one of two ways.
Prepare a clean sealable box with a bed of clean acid free tissue paper ready to receive the cleaned sherd.
Then EITHER:
Unless fabric survival is obviously unlikely, hold the sherd under a gently flowing tap and brush soil away from the surfaces. Weak fabrics will start to break up immediately, in which case stop. If the fabric allows it, however, brush sufficiently to reveal the surface colour and brush soil away from the broken edges. Leave under the flowing tap for long enough for smears to be washed away. For obvious reasons a mixer tap is a good idea -lukewarm water is better for soil removal and kinder to hands. Remember that sherds continue to soften after washing - a sherd which survives washing might not survive being picked up thereafter
For groups of sherds which look as though they might join avoid cleaning the edges if this results in damage to the sherds.
Use kitchen towel to remove surface water and place the sherd in the box.
OR:
Use a soft toothbrush to brush away soil from the vessel surfaces and from as much of the edges as possible. Take care to reveal decoration and form as much as possible consistent with not damaging the pottery.
Remove as much as possible of soil attached to small sherds and allow them to dry out as below. Once dried, small sherds should be placed in sealed, labelled polythene bags and placed in the boxes with cleaned sherds, or, if they won't fit, also labelled as belonging to that context
For all Group 1 sherds
Leave the boxes open to allow the sherds to dry fully. If the material is reasonable strong, and most will be, turn it over during drying to clear moisture trapped beneath it. Leave to dry in a fairly cool place and do not underestimate the time taken for pottery to dry out.
Group 2
Single or grouped sherds which are unstable (i.e. they tend to break up when lifted).
Remove the box lids and covering tissue paper and consider whether or not cleaning is possible as for Group 1 sherds. If not, does the pottery look as though it will contribute meaningfully to ceramic knowledge? Consider again how much of the vessel profile is present, in how many sherds and of what size, and if any decorative features are visible. If the sherds have a rim profile, or decoration, or another feature such as a moulding or lug, which has not been seen elsewhere, an attempt should be made to preserve them. Consider, and if sensible, attempt the dry brushing method described above.
If the sherds are too fragile to allow this, re-pack them in the sealed box, without allowing them to dry out, and arrange for a conservator to attend to them. The conservator should be one experienced in handling prehistoric pottery. They have to undertake much the same lifting and soil removal processes as an ordinary mortal, but the laboratory situation has the advantage that the destruction process can be halted by immediate consolidation with PVA within a vacuum chamber (rather than requiring the untreated sherds to be re-packed and subsequently unpacked, causing further damage).
Other finds from the 1995-98 excavations and the 1999 season of work comprise flakes and tools of flint, chert, and other stone, a small proportion of which has been subject to burning. Upon excavation it is best that these finds are placed between tissue in plastic boxes, since bagging them tends to cause abrasion and breakage. After excavation they should be washed, preferably under running water and the surplus water mopped off with a paper kitchen towel. Allow the material to dry before re-boxing.
Pottery from Nosterfield excavations of 1995 to 1998 has already been analysed and reported upon. There is, therefore, a background against which to consider subsequently recovered ceramic assemblages. It is suggested that the ceramic assemblage from each session of excavation should be the subject of assessment following processing as outlined above. This would have the aim of establishing:
This should inform the continuing excavation and interpretation of the area and provide a body of information which will enable the eventual programming and costing of the final project report.
It is suggested that a similar approach be taken with the lithic material.