One of our earlier posts focussed on the lowest – and earliest – of three hearths laid one of top of the other in the centre of the broch interior. In this post, we’ll look at the second of these hearths.
The earliest hearth was covered over with mixed debris to level it before a new slab was placed on top, slightly off centre within the broch and a little to the west of the centre of the earliest hearth. This brought the level of the hearth up to the top of the shelf of bedrock against which the previous hearth had been built. The centre of the replacement hearth was a large flat sandstone flag, which survived as a fragmented, badly heat-affected slab 0.95m long and 0.58m wide. To the west of the slab, fragments of edge-set stones, again badly heat-affected, may have provided a setting for the hearth stone. A thin deposit of hearth debris containing charcoal and peat ash was spread over the slab, probably representing debris of the last use of this second hearth.
A kerb-like setting of rounded beach stones curved in an arc, defining a roughly circular area around the hearth that may have acted as an activity surface. Despite the presence of the kerb, a deep deposit of organic flooring deposits interleaved with ashy hearth rake-out accumulated around the hearth and over the top of this kerb. This material apparently continued to accumulate until the central hearth was becoming unusable, at which point this hearth was also levelled and refurbished.
The flooring deposits surrounding the hearth were largely organic and contained occupation debris including a cache of hazelnut shells and the articulated remains of a small mammal, probably sheep/goat (further analysis by our osteoarchaeologist will reveal more). In some deeper pockets of this deposit, waterlogging resulted in the survival of woody fragments which will also be analysed further.
Perhaps most interestingly, during the use of this hearth there was the noticeable phenomenon of using broken or discarded quern stones for construction material. Within the floor build-up in the south half of the broch, no less than four quern stones were uncovered within various floor deposits. In addition to these, two more broken quern stones were used in the construction of the next hearth level. Another was also used as consolidation material in the flooring of the entrance passage. The deposition of quern stones in Iron Age structures is well documented (for a good introduction to instances of purposeful re-use of querns in structures and floor deposits, see Richard Hingley’s paper in PSAS 122, pp7-53) and during our interpretation we will consider in more detail this phenomenon and how it relates to the deposits at Clachtoll.
In next week’s post, we will look at the third and final hearth as well as a stone tank, perhaps for storing water.