Archaelogical
Investigations 3

3.1 Introduction
In recent years, since the Code of Practice agreed between the Department of Arts, Heritage, Gaeltacht and the Islands and the National Roads Authority (2000), major changes have taken place in the approach to archaeology on national road developments. The strategy employed on road schemes since 2001, including the M3, is a radical departure from previous strategies, where archaeological monitoring of topsoil stripping at construction stage was the means of finding new archaeological sites. The strategy now employed is innovative in terms of using techniques, such as geophysical survey, previously reserved for research projects. Most importantly, it actively seeks out previously unknown archaeological sites so that ample time and resources can be allocated to their excavation and recording prior to the start of road construction.

3.2 Environmental Impact Statement (EIS)
The archaeological and historical background of this area of Meath is outlined in the EIS. The EIS desk-top survey identified two Record of Monuments and Places (RMP) sites as being impacted by the route, which were located on the Dunshaughlin-Navan section of the route. The EIS field survey identified 15 possible sites throughout the 60km scheme. An extensive geophysical survey, carried out as part of the EIS (Section 2, Dunshaughlin-Navan), identified six definite new archaeological sites (the road was moved to avoid three) and 23 further areas of archaeological potential, that it considered may or may not be archaeological sites.

3.3 Desk-top Survey
Desk-top surveys were carried out for the whole route as part of the Constraints Studies, Route Selection Studies and EIS. The surveys were predominantly based on the State’s RMP and the files of the Sites and Monuments Record (SMR). The topographical files of the National Museum of Ireland, which is the national archive of all known artefacts, were also checked. In addition, a number of published and unpublished sources were examined, including historical maps and modern aerial photographs of the route. Townland names were also researched for possible indications of forgotten or destroyed monuments.

3 The two RMP monuments (ME038- 001 and 002) were an enclosure and an adjacent field-system, identified as cropmarks from Cambridge University Collection Aerial Photographs taken in the 1950s (Fig 3.1). Neither of these sites had any upstanding features.

3.5 Geophysical Survey

Geophysical surveys have been carried out on the entire route. The survey of the Dunshaughlin- Navan section (Section 2) and of an area at Nugentstown on the Navan-Kells section (Section 4) was carried out in 2000 and 2001 by GSB Prospection as part of the Environmental Impact Assessment. In 2002, the remainder of the scheme was surveyed by Bartlett-Clark Consultancy.

A magnetometer survey (also known as gradiometer survey) was carried out in two stages on the 15.5km Dunshaughlin-Navan section. Magnetometer scanning (unrecorded) was used during a gridded walkover of this section of the route (105 hectares) with traverses spaced at intervals of approximately 10m. During this operation, fluctuations in magnetic signal were observed on the instruments’ display panel. Any significant variations were investigated more closely to determine their likely origin. The location of those anomalies considered to have archaeological potential was recorded on a map for subsequent detailed survey.

The level of magnetic background response along the entire route was found to be low. This helped to identify relatively low fluctuations and areas where only a slight increase in magnetic response was encountered.

The sites identified were three large enclosure complexes at Roestown, Baronstown and Dowdstown (Figs 3.5 – 3.7). The morphology of the sites indicated that both Roestown and Dowdstown were likely to be early medieval settlements while Baronstown could be early medieval or prehistoric. The sites subsequently avoided by the route were another enclosure complex at Garretstown (Fig 3.8) and two small circular enclosures at Berrilstown and Skreen (Figs 3.9 – 3.10). The square shape of the enclosure at Garretstown indicated that it was likely to be a medieval moated site, while both of the small circular enclosures were typical of ringditch burial sites. A magnetometer survey was also carried out over a 9-hectare area in Nugentstown on the Navan-Kells section (Section 4), where a possible burnt mound was identified.

The remainder of the route (Sections 1, 3-5) was investigated by magnetometer and magnetic susceptibility survey. Magnetometer readings were recorded along parallel strips 9m wide spaced 11m apart running along the length of the landtake. This amounted to some 45% of the total site area. The magnetic susceptibility survey was generally carried out along the magnetometer strips, with readings taken at 12.5m intervals.

The magnetic susceptibility survey was used to complement the magnetometer survey, as while the results which can be obtained from these forms of survey are related, they will not necessarily detect the same features or disturbances.

Roestown

Fig 3.5: Early medieval D-shaped enclosure at Roestown, geophysical interpretation and greyscale

Baronstown

Fig 3.6: Enclosure complex at Baronstown, geophysical interpretation and greyscale

Dowdstown  

Fig 3.7: Early medieval enclosure complex at Dowdstown, geophysical interpretation and greyscale

Garretstown

Fig 3.8: Medieval moated site at Garretstown, geophysical interpretation and greyscale

Berrilstown

Fig 3.9: Penannular ring-ditch at Berrilstown, geophysical interpretation and greyscale

Skreen

Fig 3.10: Penannular ring-ditch at Skreen, geophysical interpretation and greyscale

3.6 Test Trenching

The EIS recommended archaeological testing of all known and possible archaeological sites identified. Meath County Council made a commitment at the An Bord Pleanála hearing that archaeological testing of the whole route (including known, presumed and areas of unknown archaeological potential) would be carried out as early as possible in advance of construction. This work would ensure adequate time to excavate and preserve, through recording and publication, any archaeological sites that could not be preserved in situ.

The purpose of the testing was to determine the presence or absence of archaeological features, structures, deposits, artefacts or ecofacts along the whole route. This included the test excavation of known and possible sites identified in the EIS and subsequent studies, and test trenching the remainder of the route with test excavation of any archaeological remains uncovered. Where archaeological remains were present the testing endeavoured to establish the nature and extent of the archaeological deposits and features present, to allow an assessment to be made of the archaeological impact of the proposed development. The testing also included assessing a number of rivers and streams crossed by the route by underwater and metal detection survey or wading and metal detection survey (Fig 3.3)

. Archaeological testing took place between March-December 2004. Sections 1-3 were tested by Archaeological Consultancy Services Ltd. and Sections 4-5 by Irish Archaeological Consultancy Ltd. Each section of the route was divided into testing areas with the work carried out under licence issued by the Department of the Environment, Heritage and Local Government following consultation with the National Museum of Ireland. Testing generally involved mechanically excavating a 2m wide trench through the already agriculturally disturbed topsoil along the centreline of the route and excavating perpendicular offset trenches to the edge of the landtake every 20m. The patterning of these trenches was calculated to identify all concentrations of archaeological features.

The topsoil was removed to expose the upper surface of archaeological features where present, otherwise the trench simply exposed the upper surface of drift geology underneath topsoil. Once features were identified, a limited amount of hand excavation was carried out in order to access the nature and extent of the remains present. Over 300km of trenching has resulted in approximately 10% of the route being opened and archaeologically investigated.

3.7 Testing Results

The results to date, in terms of both numbers and types of sites, are very much consistent with those from similar schemes nationwide. Approximately 160 archaeological sites have been identified on the whole route, which covers an area of circa 700ha. 25% of these sites (38) were identified on the Dunshaughlin-Navan section of the route, which is also 25% of the scheme in area. Looking more closely at the 6.5km of the road in proximity to the Hill of Tara, which in area represents 11% of scheme, the numbers are still average with 17 sites representing 11% of the total. These sites vary from a single pit to a complex of enclosures and probable cemeteries dating from the Neolithic to the 20th century AD. Such a frequency of archaeological sites is entirely typical for a road scheme of this size. The term ‘archaeological site’ in general and as applied on this project covers a wide range in terms of size, date, complexity and significance, and for this reason it is inappropriate to place too much emphasis on numbers of sites.

3.8 Correlation between EIS and Test Trenching Results

No ancient archaeological artefacts or features were identified by any of the investigations at the site of the two RMPs (cropmarks) impacted by the road. This was despite opening the trenches to three times the standard size and leaving them open for a number of days. One of the 15 possible sites identified by field survey was revealed to be an archaeological site – a burnt mound at Knocks townland, near Dunshaughlin.

All sites identified as definitely archaeological by the Dunshaughlin-Navan geophysical survey were confirmed by testing. At these sites there was a strong correlation between the features identified in the geophysical survey and those identified in the testing. Six of the 23 areas of potential were shown to represent archaeological sites while the remainder were identified as being either modern or geological features.

Part 3 – Archaeological Investigations 3 12 The M3 Clonee to North of Kells Motorway; Archaeology Information Series; NRA & Meath County Council