Neolithic and Bronze Age Landscapes of North Mayo: Report 2011

Construction Techniques
Often it is not possible to determine the nature of wall construction due to concealment, collapse
and occasional robbing. Where they are sufficiently exposed a variety of construction types are
evident, sometimes in the same system and even in the same wall but often the construction seems
to be determined by the type of stone available. The walls can be divided into different types:
1. Walls can appear as a collapsed linear cairn with no orthostatic stones or foundation course
visible although low foundation courses may be concealed by the collapse. This wall type
was common at Castletown where a lot of sea rolled stones from the adjacent shore were
used. Similar walls were less common on Carrowmore and Rathlackan where the local
sandstone was used. At Rathlackan court tomb the excavated western portion of the
enclosure wall abutting the cairn was built of horizontally laid stones which survived up to
0.7m high and was from 1.0 to 1.5m wide.
2. Single stone walling with a foundation of regularly set boulders. This was common at both
Barnhill and Seefin (Figure 7) where erratic granite boulders were set at intervals with
smaller loose stones between.
3. Single stone walls with set upright slabs or blocks aligned with the wall at intervals. Often
seen at Carrowmore and Rathlackan and also in the single wall near Aghaleague court tomb.
The N – S wall to the west of Rathlackan court tomb had frequent slabs up to 1m long with
smaller stones between.
4. Single stone walls with slabs set upright transversely to the wall. Only two clear examples
were found – the straight wall SE of H11 on Carrowmore, where slabs up to 0.8m wide and
0.5m high were set at intervals of 0.6m to 6m, and a section S of Site C in Rathlackan.
5. Double stone walls with a foundation of a double row of set stones or slabs were common
on both Rathlackan and Carrowmore such as the field wall incorporated in Doonadoba H10
(Figure 16) which has a width of 0.65m to 1.0m.
6. Double stone walls with a foundation of two widely spaced rows of facing stones with rubble
between were mostly found at Rathlackan. The best example is the enclosure incorporating
the lintelled entrance Site D where the E – W straight section is 2.0m wide (Figure 7) but the
remainder averages 1.0m wide.
7. Earthen banks and ditches. Only two examples, already mentioned, were located - one at
Castletown and the smaller section at Carrowmore that was possibly a drain.
8. A single instance of earthen bank without a ditch was also found at Castletown.
Size
Without excavation it is difficult to be certain of the original size of the walls although probed
profiles can indicate the volume of stone used. Where foundations are visible the width is mostly 1m
or less but can be up to 2m. In modern dry stone wall building it is recommended that the
foundation width be half the wall height (McAfee 1997, 103). Occasionally they have survived to a
height of 0.8m to 1.0m which would be the minimum original height.
148