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 Corlea Trackway
In 1984, at Corlea near Keenagh, Co. Longford, removal of peat by Bord na
Móna‘s production
In 1985 the roadway at Corlea was excavated under the auspices of the National Monuments Branch of the Office of Public Works.
The Corlea road was constructed of heavy planks split from oak trunks using timber wedges. These oak sleepers were between 3m and 4m long and up to 60cm wide, and were laid across parallel pairs of timber runners on average about 1.4m apart. The runners were logs of birch or ash, up to 10m in length and laid end to end directly onto the Iron Age bog surface. Where the roadway ran across wet areas of bog, several runners were used. At one point eight runners were used to bridge what was probably a difficult area. In other sections brushwood was laid as a supporting raft for the heavier timbers. Mortices were generally cut into the ends of the oak planks through which long pegs of birch or hazel were fixed to secure the road surface Thousands of timber sleepers were used in constructing the Corlea roadway which reveals a high level of woodworking knowledge and skill in Early Iron Age Ireland.
The Corlea road was a major undertaking capable of carrying wheeled vehicles.
It has been
In the course of archaeological investigations several smaller bog trackways (or toghers) were discovered in the area of Corlea. The oldest trackway was dated to the middle of the fourth millenium B.C. This was made of tightly packed layers of hazel, alder and birch placed lengthwise along the track and supported occasionally by cross timbers to form a trackway about 1.6m wide. Another track, which has been dated to about 2259 B.C., crossed over the earlier Neolithic path at one point. The depth of peat between the trackways, about 80cm, illustrates how the bog was growing during that time. This trackway was constructed of substantial timbers of oak and ash laid across branches of birch which had been placed lengthwise along the path to create a track between 2m and 2.5m wide. A brushwood track dated to about 1200 B.C. was made of tight bundles of long hazel rods laid along the path to form a trackway about 1.5m wide and up to 25cm thick. A simple narrow trackway, dating from about 587 A.D. was made of single oak planks, up to 30cm wide, laid end to end on short transverse supports.
While the Iron Age road at Corlea lay hidden under the peat which had engulfed it, the ancient timbers were preserved in the bog‘s watery anaerobic environment. But the discovery of the roadway exposed the waterlogged timbers to the atmosphere where they would rapidly deteriorate without conservation measures. The techniques required to preserve these timbers are highly specialised and costly. Nevertheless such was the importance of the archaeological remains that the Office of Public Works approached Bord na Móna with a view to preserving a 20m section of the road, together with an adjoining 4 ha of intact raised bog in which a section of the trackway would remain undisturbed in waterlogged conditions. Bord na Móna transferred its interest in the site and carried out work to preserve the raised bog remnant. The main feature in the conservation of the raised bog was the insertion of a plastic membrane around its perimeter to prevent seepage of water and to maintain the moisture content of the bog at around 95%. Today the Corlea Trackway Visitor Centre houses the section of preserved roadway, and audio visual presentations and exhibitions there tell the fascinating story of ancient wetland trackways in Ireland. |
machinery
revealed a great timber roadway which had lain buried in the bog for
centuries. Tree ring analysis carried out at Queen‘s University, Belfast
revealed the trees used were felled late in 148 B.C. or early in 147 B.C and
identified the roadway as the only known example in Ireland of an Early Iron
Age road.
The
road, which was made of massive oak planks, extended for over one kilometre
across the bogland, connecting an isolated drumlin island of mineral soil with
the mainland. A similar trackway had extended westwards from the drumlin
island across the bog at Derraghan for one kilometre. Dating of this roadway
showed it to be of the same age as the Corlea road and established the
existence, over two thousand years ago, of a substantial road system capable
of carrying wheeled traffic.
speculated
that it may have been part of an ancient highway linking the pagan ceremonial
sites of Cruachain in Connaught and the Hill of Uisneach in Leinster, but its
precise function is as yet unclear.
These
trackways were probably built to allow the early inhabitants of the region
maintain contact between communities across the expanses of inhospitable and
treacherous wetlands.
