Generally, fieldwork to investigate Mesolithic and Palaeolithic archaeology in Scotland will be undertaken in a wide range of landscapes where complex geomorphological processes have had a profound influence on the surviving archaeological and palaeoenvironmental remains. These processes provide a unique challenge to the researcher prospecting for hunter-gatherer sites and it is necessary to provide brief overviews here of the landscape forms in which fieldwork will take place.
The Coastal Zone
Changes in sea level in Scotland have serious implications for trying to understand the influence of the coast upon previous settlement patterns and their survival (see section 3.4). This is especially significant given that local manifestations of these processes can be complex. The consequences of sea-level change are dramatic; a substantial portion of the late Pleistocene and early Holocene coastline has been lost owing to the final transgression of the sea (Smith et al.2011). Coastal sites have been revealed by erosion, but here the pattern and distribution of sites is skewed, providing a bias in the archaeological record. Present and fossil shorelines, including raised beaches, abandoned sea caves and rock shelters have, however, provided a rich and varied Mesolithic settlement record for Scotland. Submerged forests and offshore peat deposits offer valuable palaeoenvironmental data and may also yield direct archaeological evidence (see for example Bell 2007; Bell et al. 2006).
Much of the evidence for the inland Mesolithic is riverine, frequently being recovered from ploughed areas along valley bottoms or on lower terraces immediately above these. It can be assumed that a better understanding of the patterns of evidence presently known regarding the use of river systems during the Palaeolithic and Mesolithic will depend on a wider understanding of geomorphological data. River systems are inherently dynamic (Brown 1997), and river profiles have changed considerably during the Holocene. The local depositional and erosional sequence associated with river systems is especially significant in upland areas while to further complicate matters, river systems, because of their importance to settlement of all periods have often been extensively managed and transformed by agricultural and other anthropogenic activities, especially in recent centuries. Nevertheless, the opportunites for important discoveries along tidal rivers and in estuarine contexts have been highlighted by recent work in south-west Britain (e.g. Bell et al. 2000; 2006).
The majority of evidence for Mesolithic settlement in the east of Scotland, along with the extensive surveys undertaken by Mithen on the islands of Islay and Colonsay (Mithen 2000), comes from ploughsoil contexts. Most arable land occurs within river valleys or on wider coastal plains, while the occasionally ploughed and improved pasture may extend the distribution of such land into the higher parts of the landscape in the Scottish uplands. However, in places, the extent of soil movement associated with arable agriculture can be extensive. Also, where modern ploughed soils have been affected by fluvial deposition processes, the Mesolithic surfaces may be deeply buried below these accumulations of deposits. The Upper Palaeolithic site at Howburn, South Lanarkshire, would not have been found had ploughing not revealed a surface artefact scatter (Ballin et al. 2010a).
Permanent Pasture and Heather Moorland
Large areas of upland Scotland are in permanent pasture, whether improved or rough, or are covered by heath communities. In all such cases the vegetation is rarely entirely removed, or the soil surface disturbed other than very locally by livestock, or through developments of some kind. Mesolithic sites in such areas have generally only been located at the margins of water courses or more extensive water bodies where the vegetation cover has been removed or at times of low water when an exposed horizontal surface is available for examination, by targeted test-pitting, or by chance during other archaeological operations. Although extensive in area, and potentially containing many relatively undisturbed sites, these zones are amongst the most intransigent in terms of standard survey approaches (Finlayson et al. 2004).
Away from the coast, valley bottoms and neighbouring terraces, the presence of extensive peat cover creates a further barrier to the discovery of archaeological material relating to the Palaeolithic and Mesolithic. The timing of the onset of peat coverage in eastern Scottish upland landscapes is variable. In places such as Carn Dubh, Perthshire (Tipping 1995), peat was already established during the Mesolithic period, but the large-scale development of this phenomenon post-dates that period, and therefore now masks many areas of the Mesolithic landscape that would previously have been more attractive for a range of uses. Whilst blanket peat now covers some 1.1 million hectares of the Scottish landscape, the distribution of peat is not even and its presence severely limits archaeologists ability to locate sites within such upland landscapes (Finlayson et al. 2004). The early removal of peat for agricultural reclamation in some parts of Scotland, particularly areas liable to have been foci for Mesolithic movement and exploitation such as the Carse of Gowrie and the Carse of Stirling, will undoubtedly have destroyed valuable Mesolithic evidence, now only represented by a few surviving organic remains (Lacaille 1954).
One further zone of high potential, especially given the early dates noted for some peat formation, is wetland areas, which may preserve particularly good data. Although difficult in prospection terms, this particular problem is not unique to Palaeolithic and Mesolithic site recovery, but is one shared in considerable measure with at least all prehistoric periods (see papers in Coles and Olivier 2001). The potential value of these locations is widely appreciated and there seems no reason to advance specific recommendations for hunter-gatherer wetland archaeology, as a result of the heightened levels of preservation anticipated (Finlayson et al. 2004).
The mountain uplands of Scotland comprise a major part of the country’s land mass that have been, and are still, subjected to severe and variable climactic conditions. It therefore comes as no surprise that these areas have received little attention from archaeologists researching the Palaeolithic and Mesolithic periods. In the past, these upland areas would have supported a rich and diverse fauna and flora, including tree cover during the more favorable conditions that endured during the early Holocene (Roberts 1998, 99-101). Many of these upland areas would have supported large populations of ungulates, such as reindeer and red deer, and would have provided good hunting grounds for people during the summer months. Bang-Andersen has produced evidence from Norway to suggest that people were utilizing these upland landscapes in Norway during the Mesolithic (Bang-Andersen 1987) and there is increasing (if still sparse) evidence for this in Scotland (at sites such as Chest of Dee or Ben Lawers).