The Mesolithic of Scotland has generally been characterized by lithic scatters, distinctive bone and antler artefacts, and shell middens, especially in coastal locations, while the only evidence so far for Upper Palaeolithic presence consists of two lithic assemblages (see section 2.1). Few in situ features survive on many sites, while organic or faunal material is usually absent on open-air lithic scatter sites. However, a wealth of faunal evidence is preserved in the alkaline conditions of some of the shell middens and within caves and rock shelters.
Because of the rarity of cut features, it is difficult to locate Mesolithic sites through many of the more usual methods of archaeological prospection. Stone tools, many of which come from surface contexts, dominate the material. Evidence and variability in the raw materials used to manufacture stone tools, along with their size and primacy, often create significant problems in identification of Mesolithic and potentially earlier sites (Phillips and Bradley 2004). In spite of the challenging environmental constraints and other difficulties including site visibility, there has been a long tradition of Mesolithic studies in Scotland (Mithen 2000; Saville 2004b; Hardy and Wickham-Jones 2009). One of the most characteristic features of Mesolithic archaeology is the importance of local archaeologists and archaeology groups (non-institutional archaeologists) in enriching the database. A major factor, especially with local archaeologists and other interested parties, is that they recurrently examine their local area throughout the year, while institutional archaeologists work in areas for restricted time spans.
Sites are usually found where and when the ground is disturbed, for example by ploughing; by drainage ditches, roads, and tracks; by the preparation of ground for new tree planting schemes; by erosion features caused by animal disturbance, including rabbit burrows and mole hills; by more natural types of erosion features, such as the banks of streams and rivers; by commercial developments; and by the constant erosion and modification of much of the coastline. The continuing presence of the non-institutional eye in the locality is therefore a vital resource in the search for new evidence.