Re-evaluation of museum collections and existing site archives and assemblages also offers considerable potential to yield significant new insights into the period. In addition to enhancing understandings of the historiography of archaeological research in Scotland as a subject in its own right.
Many lithic collections currently held in museums relate to antiquarian and early 20th century collectors. Most have not been subject to specialist evaluation and many offer an opportunity to examine sites and landscapes which are now destroyed or no longer as accessible due to land use changes (for example see Woodman et al. 2006). This applies equally, of course, to assemblages obtained from earlier archaeological investigations. Another important area of research that has produced encouraging results is the re-examination of assemblages from cave sites housed in museums and private collections (Saville and Ballin 2009, Walker 2003). Such an evaluation should also include faunal assemblages where available as well as artefacts to consider key species relating to potential settlement during the Palaeolithic and Mesolithic periods. The consequent AMS dating of bone and antler implements from across Scotland has produced important results (Saville 2004c, table 10.2).
Earlier prehistoric artefacts and occupation evidence is commonly encountered via archaeological fieldwork taking place on chronologically later sites spanning the Neolithic to post-Medieval periods. There is a high potential for any archaeological intervention to encounter earlier prehistoric material, particularly for the Mesolithic, but often current evaluation strategies-such as mechanical topsoil stripping often militate against the identification and recovery of diagnostic material. This is unfortunate for often the only evidence that survives are lithic artefacts in these superficial contexts.
Of known Mesolithic sites in Scotland, most haveinitially been identified through local collectors and the endeavours of a number of highly dedicated non-professionals. The location of several important collections is currently unknown, for example the late Tom Affleck's Loch Doon material (Kevin Edwards and Dene Wright pers comms). The archaeological community also needs to develop procedures for 'best practice' to assist private individuals to manage and to retrospectively audit and integrate this vunerable unaccessioned resource in order to contribute to national understanding of Palaeolithic and Mesolithic occupation.
The often protracted post-excavation analysis involved in sites of this period means that several significant sites have only seen interim or incomplete publication. This has had a clearly detrimental impact on the understanding of the period and development of regional models. Notable in this respect are the still-outstanding publication of aspects of the Oronsay sites (Mellars 1987) and the results of the important excavations at Nether Mills, Crathes, Aberdeenshire (Kenworthy 1981).
The specialist re-evaluation of early collections as well as excavated assemblages still offers the potential to uncover diagnostic material originally overlooked or mis-identified at the time. Further typological, technological,and other analyses of existing assemblages also has a key role to play but rarely takes precedence, as it should, over new fieldwork campaigns.