7.6.4 Souterrains

Souterrains, underground or semi-underground structures, termed ‘earth houses’ in antiquarian literature, vary widely in date in different areas of Scotland, with the main period of use generally presumed to be the last centuries BC and first two centuries AD (ScARF Iron Age section 5.8). A number are known from the Highlands (see Map 7.4; Datasheet 7.4), with published assessments for Skye (Miket 2002) and Sutherland (Morrison 2000b) also available. Some souterrains, for example Tungadal on Skye (MHG5106) and Cyderhall in Sutherland (MHG11834) are associated with roundhouses, and surface traces suggest this is the case on Canna as well (MHG5546; Hunter 2016, 58). Shapes vary, from curves to cruciform in plan.

The function of souterrains has been much debated, with storage, refuge and ritual the main contenders. Although objects and grain have been found in some excavated examples, increasingly souterrains are thought unlikely to have been dry storage for grain activities (ScARF Iron Age section 5.8; Miket 2002). At Cyderhall pollen analysis showed significant quantities of hemp and cultivated flax, which may either have been a deposit of grains or of containers made from the fibres. The souterrain itself is unlikely to have stored grain, and there was nearby a separate grain pit dated 400–126 cal BC (GU-2633; Pollock 1992). This suggests that some of the Highland souterrains may have had a religious focus for a specific domestic structure. Of course, there need not be one single explanation for all souterrains.

Direct dating evidence is sparse (see Table 7.13). For the Highlands, the best dating comes from Broadford Medical Centre (MHG55640), where there is a date for the use of the souterrain, but also a date for when it went out of use (Birch forthcoming). At Cyderhall the associated roundhouse was dated around 400–200 cal BC (Pollock 1992), whereas another old date for the rock cut souterrain at Allt na Cille on Skye (MHG5166) was later: cal 51 BC–AD 379 (GU-2633). Further work on dating Highland souterrains is needed. Some show multi-period use, or like Tungadale were blocked up in the later phases of use of the associated building.

A number of the Highland souterrains have finds which include pottery, shale rings, beads, shells and grain. The souterrain at Fouhlin in northwest Sutherland contained a set of copper alloy shears, a rare find from Scotland. The difficulty remains in determining if these objects were contemporary with the souterrain, or part of the later infilling (Morrison 2000b, 230–1).