2000:0773 - PLATIN FORT, Meath

Platin Fort is a substantial limestone rock outcrop to the west of Drogheda and south of the Boyne Valley. The site is classified as an ‘Inland Promontory Fort’ and will be partially destroyed by the construction of the Northern Motorway. As a result, trial-trenching followed extensive aerial and topographical survey on the site.

The westernmost area of the fort was to be affected by the motorway. This roughly triangular area was not bounded by any banks. It is divided from the remainder of the fort by an irregular hollow.

Ten trenches were hand-excavated on the summit and below the fort. Trench 2 tested an irregular rocky knoll below the west of the main promontory. The trench was 3.8m north–south by 5.1m. Humic soil over 0.1m was removed. This overlay a drystone wall running north–south. It continues as a low mound on both sides. A sandy clay abutted the wall on both sides and contained medieval pottery sherds and clay pipe. This in turn overlay a patchy deposit of light brown, sandy clay with charcoal flecking, which extended under the wall. This deposit covered bedrock and a patchy, orange-brown, sterile boulder clay. In one place in the centre of the trench an irregular hollow within bedrock contained a drop of a silicate-like substance and a fragment of bronze in a charcoal-flecked clay matrix. The wall is clearly a late medieval/post-medieval component of field systems in the area.

Trench 3 measured 5m x 5m and was placed at the western edge of the promontory. Topsoil was up to 0.14m in thickness. It overlay a light brown, sandy clay, which contained frequent waste flint flakes and burnt bone fragments. In the north of the cutting it overlay bedrock, which was terraced from west to east. Elsewhere it overlay boulder clay. Trench 7 was located on the northern edge of the promontory and was 5m x 3m. Topsoil of 0.2m overlay bedrock. In the south of the cutting it overlay a light brown, sandy clay, which was 0.32m in depth and overlay natural boulder clay.

Trench 8 was excavated in the centre of the area of the promontory under investigation and was 5m x 5m. Topsoil was 0.1–0.2m in thickness. In the north of the trench this overlay a layer of sandy, light brown clay up to 0.2m in thickness, which contained sparse flint flakes. It contained cattle bone and other unidentified weathered bone fragments. These layers overlay bedrock. A flat platform, 1.47m x 1.42m, was uncovered cut into bedrock. This platform was surrounded by a number of holes in the bedrock. One measured 0.3m x 0.1m x 0.3m in depth and contained burnt stone, burnt bone and charcoal. Three other hollows of similar dimensions were uncovered, which contained charcoal-flecked, light brown clay.

Trench 9 was placed on the east of the promontory and was 5m x 5m. Topsoil was up to 0.1m in thickness and overlay a light brown, sandy clay, 0.12m in thickness. This in turn overlay an orange-brown, sandy clay up to 0.16m in thickness. It contained sparse charcoal fragments, flint debitage and 24 sherds of ceramics, some of which were only crumbs. The majority of the pottery appears to be in the Western Neolithic tradition. A radiocarbon date of 4090+30 BP (GrN-25814, Gronigen) was obtained for charcoal in this layer. This, in combination with the pottery, suggests that there was considerable disturbance of soil layers in the Bronze Age. This layer overlay natural boulder clay. Trench 10 was placed in the south of the promontory. Humic topsoil contained a mixture of very weathered animal bone and modern pottery and was up to 0.18m in depth. It overlay bedrock.

Trench 11, measuring 5m x 5m, was placed on the eastern edge of the area within the proposed road-take on the promontory, on the slopes of the hollow that divides the promontory. Topsoil was 0.6m in depth. This overlay a layer of light brown, sandy clay that contained sparse charcoal flecks. It contained ceramics of probable Neolithic date, flint debitage, blades, a core and a miniature bronze flat axe (of Early Bronze Age date). A quantity of animal bone was also recovered from this context. This layer overlay a substantial deposit of tumbled angular limestone rocks that probably represent glacial scree. In places these stones could be seen to overlie orange-brown natural. This trench was not fully excavated as it was deemed that the sensitivity of the deposits required full excavation to determine their significance.

Three long trenches were excavated below the promontory. Trench 5 was placed perpendicular to the western end of the promontory and was 20m x 2m. Topsoil was up to 0.2m in thickness. This overlay a light brown, sandy clay that was 0.2m in thickness and contained post-medieval pottery. This layer overlay a lighter brown, sandy clay that contained modern pottery and a convex flint scraper. This overlay a light yellow, compact boulder clay with frequent decayed stone chips. In the west of the trench a sondage uncovered a sterile, grey silt layer under ploughsoil.

Trench 6 was placed perpendicular to the edge of the promontory on the northern side of the promontory and was 20m x 2m. Topsoil was 0.04–0.12m in depth and sloped from south to north. It overlay a thin layer of orange-brown soil. This overlay a thick layer of mid-brown, sandy clay that contained flint debitage and a retouched blade and was up to 0.3m in depth. In the southern half of the trench this overlay a charcoal-flecked, orange-brown clay that contained large fragments of glacial scree. In the north of the trench it overlay grey-brown boulder clay. In the south of the trench a sondage suggested that this layer overlay a light brown, sterile sand. A ditch running east–west was sealed by ploughsoil and contained a light brown, sandy clay. An iron knife with a bone handle was recovered from the fill, and a large number of stones were uncovered at its base, suggesting a bank that was pushed back into the ditch.

Trench 4 measured 20m x 2m and was placed perpendicular to the sloping southern side of the promontory. Topsoil was 0.1–0.14m deep and contained collapsed stone closest to the promontory. This overlay light brown, sandy clay in the north of the trench containing weathered animal bone, a human phalange, burnt stone, flint and a bronze thimble. It also contained a number of sherds of pottery in the Carrowkeel and Western Neolithic traditions. The human bone is currently being radiocarbon dated. This overlay large limestone blocks. In the south of the trench topsoil overlay mid-brown, sandy clay ploughsoil. Ploughsoil contained modern artefacts and a number of retouched flint tools. It overlay a light orange-brown, sandy clay with no inclusions, which in turn sat on grey, compact, silty boulder clay.

In summary, trial excavations have established that activity has taken place on the summit from the Early Neolithic to the Middle Bronze Age. This includes the possible deposition of high-status objects such as the flat axe, flint-working and possibly the treatment of the dead. There is some evidence for deliberate shaping of the rock to form platforms and hollows. It is likely that Bronze Age activity disturbed earlier Neolithic deposits. There is little evidence to suggest that the rock was a promontory fort. The distinctive nature of the Platin outcrop is likely to have figured strongly in local prehistoric geographies and mythologies. The nature of limestone and its susceptibility to freeze–thaw and water action have led to considerable collapse and will mean that many artefacts will not be in their original contexts. Later post-medieval activity is present in the form of low banks and ditches that make up field systems in the area. Full excavation of the affected area was recommended.

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