Archaeological Report - Drumroe, Co. Offaly (Ireland)

Issue 11 [ISSN 2009-2237]

Archaeological Excavation Report

E3773 - Drumroe, Co. Offaly

Late Bronze Age structure, Iron Age pits and late medieval field boundaries

Eachtra Journal

July 2011


Co Offaly

Laois County Council and National Roads Authority

Enda O'Mahony and John Tierney

Drumroe

EACHTRAArchaeological Projects

E No:

:

Project:

Client:

Date:

E3773

N7 Castletown to Nenagh (Contract 1)

John TierneyExcavation Director

Written by:

Late Bronze Age structure, Iron Age pits and late medieval field boundaries

CORKThe Forge, Innishannon, Co. Cork

tel: 021 4701616 | web: www.eachtra.ie | email: [email protected]

GALWAY Unit 10, Kilkerrin Park, Liosbain Industrial Estate, Galway

tel: 091 763673 | web: www.eachtra.ie | email: [email protected]


DrumroeCo Offaly

Excavation Director

John Tierney

Written By

Enda O'Mahony and John Tierney

EACHTRAArchaeological Projects

© Eachtra Archaeological Projects 2011 The Forge, Innishannon, Co Cork

Set in 12pt Garamond

Printed in Ireland

i

Table of ContentsSummary��iii

Acknowledgements�� iv

1 Scopeoftheproject�� 1

2 Routelocation�� 1

3 Receivingenvironment�� 3

4 Archaeologicalandhistoricalbackground�� 4Mesolithic�(c��8000�to�4000�BC)�� 4

Neolithic�(c��4000�to�2000�BC)�� 4

Bronze�Age�(c��2000�to�600BC)�� 4

Iron�Age�(c��500�BC�to�AD�500)�� 6

Early�medieval�period�(c��AD�400�to�1100)�� 6

High�and�later�medieval�periods�(c��AD�1100�to�1650)�� 7

Post-medieval�period�(c��1650�to�the�present)�� 7

5 SitelocationandTopography�� 7

6 Excavationmethodology�� 10

7 Excavationresults�� 11

8 Discussion��26

9 References�� 31

Appendix1 StratigraphicIndex�� 33

Appendix2 SiteMatrix��34

Appendix3 Groupsandsubgroups�� 37

Appendix4 Lithicsreport�� 43

Appendix5 Animalbonereport��45

Appendix6 Plantremainsreport��46

Appendix7 Geophysicsreport��50

ii

List of FiguresFigure1: The route of the N7 Castletown to Nenagh overlain on the Ordnance Survey

DiscoverySeriesmap�� 2

Figure2: The route of the N7 Castletown to Nenagh overlain on the Ordnance SurveyDiscoverySeriesmapwithalltheexcavationsitesmarked�� 5

Figure3: Portionof the IsteditionOrdnanceSurveyMapOF47showingthe locationofDrumroe�� 8

Figure4: LocationandextentofDrumroeE3773ontheN7CastletowntoNenagh�� 9

Figure5: PostexcavationplanofDrumroe�� 12

Figure6: Post-excavationplanofStructureAatDrumroe�� 13

Figure7: Sectionandprofileplansofhearthandpost-holeC�46andC�66andpost-holesC�150andC�171associatedwithStructureA��16

Figure8: SectionandprofileplansofpitsC�17,C�21andC�134atDrumroe��18

Figure9: SectionandprofileplansofditchesC�4andC�41,ditchC�53andditchesC�144andC�50atDrumroe��20

Figure10: MapofthegeophysicaldatasouthofthesiteatDrumroe��25

Figure11: Post-excavationplansofeightoftheBronzeAgehousesontheN7CastletowntoNenagh��27

List of PlatesPlate1: AerialviewofDrumroefromeast�� 11

Plate2: PostexcavationofStructureAatDrumroelookingwest�� 14

Plate3: PostexcavationofStructurelookingeast,hearthC�46inforegroundatDrumroe�� 17

Plate4: Post-excavationofpitC�21inDrumroe�� 17

Plate5: Post-excavationofpitC�134inDrumroe�� 19

Plate6: SectionofditchesC�4andC�41fromsouthatDrumroe��21

Plate7: SectionoftheditchC�53lookingeast��21

Plate8: SectionoftheditchC�5lookingwest��22

Plate9: ConvexEndScraper(E3773:1:2)��23

List of TablesTable1: DimensionsoffeaturesassociatedwithStructureA�� 14

Table2 Dimensionsoftheditcheswithintheareaofexcavation��22

Table3: RadiocarbondatesfromDrumroe��24

Table4: RadiocarbondatesforBronzeAgestructuresontherouteoftheN7��28

Drumroe-e3773

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http://eachtra.ie/index.php/journal/e3773-drumroe-co-offaly/

SummaryThe excavated remains at Drumroe comprised a Bronze Age house, a group of pits and a number of field boundaries. The area of excavation measured 35 m north-south by 110 m east-west. The Bronze Age house was located at the eastern end of the site. The house measured 7 m in diameter. It was defined by two incomplete rings of post-holes and slot trenches, the inner ring was concentric with the outer. No trace of the rear of the struc-ture survived. The porch measured c. 1 m in width by 1.7 m in length and faced directly east. A widely dispersed group of sixteen pits and field boundaries were recorded in the western portion of the site. The boundaries were of relict field systems. At least three phases of ditches were recorded and a broad typology of ditches can be associated with the three phases.

Road project name N7 Castletown to Nenagh Site name DrumroeE no. E3773Site director John TierneyTownland DrumroeParish CastletownelyCounty OffalyBarony ClonliskOS Map Sheet No. OF47National Grid Reference 205195 / 181703Elevation 155m O.D.

iSSue 11: eachtra Journal - iSSn 2009-2237 archaeological excavation report

iv

AcknowledgementsThe project was commissioned by Laois County Council and was funded by the Na-tional Roads Authority under the National Development Plan (2000-2006). The project archaeologist was Niall Roycroft. Kildare County Council supervised the archaeological contract with RE staff of Pat Dowling and Colum Fagan. Kildare County Council Sen-ior Executive Engineer was Joseph Kelly and Kildare County Council Senior Engineer was John Coppinger. The senior archaeologist was John Tierney and the post-excavation manager was Jacinta Kiely. Illustrations are by Maurizio Toscano, photographs by John Sunderland and Eagle Photography and aerial photography by StudioLab. Specialist anal-ysis was carried out by James Bonsall (Earthsound Archaeological Geophysics), Mary Dillon, Penny Johnston, Margaret McCarthy, Farina Sternke and the 14 Chrono Centre at Queen’s University Belfast.

Drumroe-e3773

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1 Scope of the project Eachtra Archaeological Projects were commissioned by Laois County Council and the National Roads Authority to undertake archaeological works along 17.1 km (Contact 1) of the 35km N7 Castletown to Nenagh (Derrinsallagh to Ballintotty) national road scheme (EIS approved in November 2005). The scheme runs from the eastern junction of the present N7 Nenagh Bypass, North Tipperary a tie in to the M7/M8 Portlaoise-Castletown scheme to the south of Borris-in-Ossory in County Laois. The scheme is ap-proximately 191 hectares. Contract 1 comprises the western half of the scheme and runs from Clashnevin to Castleroan passing along the Tipperary North and Offaly county border regions. The Ministers Direction Number is A38.

It was funded by the Irish Government under the National Development Plan 2000-2006. The total archaeological cost was administered by the National Roads Authority through Laois County Council as part of the Authority’s commitment to protecting our cultural heritage. The purpose of the archaeological services project was to conduct ar-chaeological site investigations within the lands made available for the scheme and to assess the nature and extent of any new potential archaeological sites uncovered.

Phase 1 of the project (archaeological testing of the route) was carried out in 2007 under licence E3371, E3372 and E3375-8 issued by Department of the Environment Heri-tage and Local Government (DoEHLG) in consultation with the National Museum of Ireland. The principal aim of this phase of the project was to test for any previously un-known sites by a programme of centreline and offset testing and to test sites of archaeo-logical potential identified in the EIS.

Phase 2 of the project (resolution) involved the resolution of all archaeological sites identified within the proposed road corridor prior to commencement of the construction of the road. This phase of the project was carried out from June 2007 to February 2008 and excavations were conducted under the management of a Senior Archaeologist. A total of 27 sites were excavated during this phase of works under separate licences issued by DoEHLG.

A post-excavation assessment and strategy document was prepared in Phase 3 of the project to present a management strategy for dealing with post-excavation work aris-ing from archaeological works along the route of the new N7 Castletown to Nenagh. It included a proposal for post-excavation and archiving work and a budget for the works.

2 Route locationThe route of the N7 Castletown to Nenagh road is located in Counties North Tipperary and Offaly (OF) (Figure 1). The project (Contract 1) involves the construction of c. 17.5 km of the N7 from Clashnevin east of Nenagh to Castleroan south-east of Dunkerrin. It passes through the townlands of Clashnevin, Derrybane, Newtown, Lissanisky, Killeisk, Garavally, Derrycarney, Garrynafanna, Gortnadrumman, Kilgorteen, Falleen, Knock-ane, Clash, Park, Rosdremid (OF), Clynoe (OF), Cullenwaine, Moneygall, Greenhills,

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Drumbaun, Busherstown (OF), Drumroe (OF), Moatquarter, Loughan (OF) and Cas-tleroan (OF). The townlands are located in the parishes of Ballymackey, Cullenwaine, Castletownely, Rathnaveoge, Finglas and Dunkerrin and the baronies of Upper Ormond, Ikerrin and Clonisk,

The route begins at the eastern end of the Nenagh bypass at Clashnevin c. 5 km east of Nenagh and continues eastward on the northern side of the existing N7 in Co. Tip-perary. It crosses a number of third class roads to the north of Toomyvara and 0.7 km east of Clash crossroads crosses the Ollatrim River. It extends into County Offaly directly east of Park. From here it crosses the R490 0.6 km north of Moneygall. It extends back in County Tipperary and through the demesne of Greenhills before crossing the existing N7 at the junction of Greenhills and Drumbaun townlands. It crosses back into County Offaly and climbs east into Busherstown and Drumroe. It crosses the Keeloge Stream into Moatquarter in County Tipperary and extends northeast back into County Offaly through the townlands of Loughan and Castleroan 1.4 km southwest of Dunkerrin.

3 Receiving environmentNorth Tipperary is bounded on the west by the River Shannon and Lough Derg with the Silvermines, to the south, and small hills extending towards Devilsbit and Borrisnoe Mountains to the east. The mountains are composed largely of Silurian strata and Old Red Sandstone. Copper, silver and lead deposits have been mined in the Silvermines. The geology of the lowlands consists of Carboniferous limestone covered by glacial drift in addition to tracts of raised bog.

The western portion of the study area is drained by the Ollatrim River which flows westwards into the River Ballintotty which in turns drains into the River Nenagh. The eastern portion is drained by the Keeloge Stream and other small water sources. These rise in the foothills of the Silvermine Mountains and flow north. The Keeloge drains into the Little Brosna River c. 1 km south of Shinrone, Co Offaly. The Brosna turns north and drains into the Shannon south of Banagher.

The largest population centre in the area is Nenagh. The smaller population centres, are Toomyvara, Moneygall and Dunkerrin.

The soils on the route are characterised by 80% grey brown podzolics, 10% gleys, 5% brown earths and 5% basis peat. They are derived from glacial till of predominantly Car-boniferous limestone composition. These soils occur in Tipperary and Offaly and have a wide use range being suitable for both tillage and pasture (Gardiner and Radford 1980, 97-99). Land use along the route was a mix of grassland devoted to intensive dairying and cattle-rearing and tillage.


4

4 Archaeological and historical backgroundArchaeological sites of numerous periods were discovered along the route of the new road (Figure 2). The periods are referred to as follows: Mesolithic (c. 8000 to 4000 BC), Neo-lithic (c. 4000 to 2000 BC), Bronze Age (c. 2000 to 600 BC), and Iron Age (c. 500 BC to AD 500), early medieval period (c. AD 500 to 1100), medieval period (c. AD 1100 to 1650), post-medieval period (c. AD 1650 to the present).

Mesolithic (c. 8000 to 4000 BC)The earliest known human settlement in Ireland dates from the Mesolithic period (c. 8000 BC - 4000 BC). The majority of the evidence (flint scatters) for Mesolithic occupa-tion has come from the river valleys. No evidence for the Mesolithic was recorded on the route.

Neolithic (c. 4000 to 2000 BC)The Neolithic Period is characterised by the introduction of agriculture and the begin-nings of the clearance of the woodlands. The population increased and became more sedentary in nature. The most important Neolithic site in the vicinity was at Tullahedy recorded on the route of the Nenagh by-pass. It was a specialist chert arrow manufactur-ing site.

No evidence for a Neolithic site was recorded on the route but stone tools dating to the Neolithic were recorded at Busherstown E3661, Clash E3660, Cullenwaine E3741 and Greenhills 2 and 3 E3637 and E3658. Stone tools dating to the late Neolithic/Early Bronze Age were recorded at Busherstown E3661, Castleroan E3909, Cullenwaine E3741, Derrybane 1 E3585, Drumroe E3773, Greenhills 1 E3638 and Moatquarter E3910. Neo-lithic pottery was recorded at Cullenwaine E3741 and Drumbaun E3912.

Bronze Age (c. 2000 to 600BC)The Bronze Age is characterised by the introduction of metallurgy and an increase in settlement and burial sites. Copper ores were mined and copper, bronze and gold items manufactured. The range of burial site types includes cist graves, pit and urn burials, cremation cemeteries, barrows, ring-ditches and wedge tombs. Stone circles and stand-ing stones also date to the Bronze Age. Both enclosed and unenclosed settlement sites are known. The most prolific Bronze Age site type is the fulacht fiadh. These monuments survive as low mounds of charcoal rich black silt, packed with heat-shattered stones, and generally situated close to a water source. Fulachta fiadh are generally classified as ‘cook-ing places’, whereby stones were heated in a hearth and subsequently placed in a trough of water, the water continued to boil with the addition of hot stones and wrapped food was cooked within the hot water. The trough eventually filled with small stones, ash and charcoal that were removed, forming the basis of the familiar mound.

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Two new fulachta fiadh or burnt mounds were recorded at Clashnevin 1 E3586, Cull-enwaine E3741 and six at three separate locations in Greenhills, E3638, E3637 and E3658. Evidence of nine roundhouses or partial round structures were recorded; two at Cas-tleroan E3909, Derrybane 2 E3591 and Drumbaun 2 E3912 and one at Clash E3660, Drumroe E3773 and Moatquarter E3910.

Iron Age (c. 500 BC to AD 500)Up to recently there was little evidence of a significant Iron Age presence in Munster. Settlement sites are few and far between as well as being difficult to identify (Woodman, 2000) while the material culture of this period is limited. Linear earthworks, believed to have marked tribal boundaries, and hillforts are two of the most visible monuments of the period. Ten percent of sites excavated on NRA road schemes in recent years have produced Iron Age dates. The dates have led to the identification of 30 new Iron Age sites in Munster from road schemes in counties Cork, Limerick and Tipperary (McLaughlin 2008, 51). These include a ditched enclosure in Ballywilliam and a wooden trackway in Annaholty Bog excavated on the route of the N7 Nenagh-Limerick (Taylor 2008, 54).

Three Iron Age dates were returned from pits in Castleroan E3909 and Drumroe E3773 on the route of the N7 Castletown to Nenagh (Contract 1).

Early medieval period (c. AD 400 to 1100)The early medieval period is characterised by the arrival of Christianity to Ireland. The characteristic monument type of the period is the ringfort. Ringforts are the most nu-merous archaeological monument found in Ireland, with estimates of between 30,000 and 50,000 illustrated on the first edition of the Ordnance Survey 6” maps of the 1840’s (Barry 1987). As a result of continued research, the construction of these monuments has a narrow date range during the early medieval period between the 7th and 9th centuries AD. Although there are some very elaborate examples of ringforts, they often take the form of a simple earth or stone enclosure functioning as settlements for all classes of secu-lar society (Stout 1997).

North Tipperary is rich in early ecclesiastical sites and the remains of these religious centres are at the core of some of the towns and villages. Roscrea, for example, was chosen by St Cronan as a location for his monastery in the seventh century as it was located at the crossroads on the Slighe Dála, an important roadway in early medieval times (NIAH 2006, 4-8).

Early medieval activity was recorded at five sites on the route of the N7 Castletown to Nenagh (Contract 1). A series of corn-drying kilns were recorded at Busherstown E3661. A denuded ringfort (OF046-013) was excavated at Clynoe 2 E3774. An area of iron-working and associated pits was recorded at Drumbaun E3912. Iron working activity, corn-drying kilns and settlement activity was recorded at Park 1 E3659. A group of pits and associated ditch were recorded at Drumroe E3773.

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High and later medieval periods (c. AD 1100 to 1650)This period is characterized by the arrival of the Anglo-Normans and the building of tow-er houses. The Anglo-Normans obtained charters in the thirteenth century for the towns of Nenagh, Roscrea, Thurles and Templemore and established markets. Nenagh grew rapidly in the aftermath of the granting of the lands of Munster to Theobald fitzWalter in 1185 (ibid. 8). Moated sites represent the remains of isolated, semi-defended homesteads in rural areas. They were build mainly in the late thirteenth and early fourteenth cen-turies in counties, such as Wexford, Kilkenny, Tipperary, mid-Cork and Limerick, that were colonised by English settlers (O’Conor 1998, 58). The Archaeological Inventory for North Tipperary lists 39 moated sites (2002, 298).

A medieval enclosure and associated field systems were recorded at Killeisk E3587. A newly recorded moated site was excavated at Busherstown E3661. A series of ditches and settlement activity was recorded at Park 1 E3659.

Post-medieval period (c. 1650 to the present)The post-medieval period is characterised by mills, limekilns, workhouses, country hous-es and associated demesnes, vernacular buildings and field systems (Figure 3). A small Demesne associated with a county house was recorded at Greenhills.

5 Site location and TopographyThe site at Drumroe 1 was located in the northern portion of the townland (Figure 4). Drumroe townland ranges in height from 136m O.D. to 200m O.D., slopes to the north-east and contains 296 acres of land. The townland name most likely refers to the “Red Hill” derived from Drum meaning “hill/ridge” and Roe meaning “Red”. The townland is enclosed by a local tertiary road to the north which facilities a journey between Money-gall and Moatquater. The townland boundary to the east comprised a small stream. The southern and western townland boundaries are field boundaries. The southern, western, and eastern boundaries are also the county boundary between Offaly and Tipperary North Riding. In the north eastern corner of the townland there are the remains of a Church and a Graveyard (OF047-009 and OF047-009001). The townland and the sur-rounding landscape is undulating with both tillage and pastoral agricultural being the predominant land use. The field boundaries show no significant alterations since the mid-19th century. There is a very gentle gradient in the area of the excavation which sloped from south to north. The moated site at Busherstown E3661 was located c. 400m to the west and downslope of Drumroe.

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6 Excavation methodologyThe site was mechanically stripped of topsoil under strict archaeological supervision. Stripping was done with a tracked machine with a flat toothless bucket. Topsoil stripping commenced in the areas of identified archaeology and continued radially outward until the limit of the road take was reached or until the limit of the archaeological remains was fully defined. Two areas were stripped systemically. The area stripped measured ap-proximately 3850sq metres. A grid was set up in the excavation areas and all archaeological features were sufficiently cleaned, recorded and excavated so as to enable an accurate and meaningful record of the site to be preserved. The excavation, environmental sampling, site photographs, site drawings, find care and retrieval, on-site recording and site archive was as per the Procedures for Archaeological works as attached to the licence method statements for excavation licences.

The site was excavated from the 17th November 2007 to the 8th December 2007. The crew comprised one director, two supervisors and 8 site assistants. Only areas within the LMA (lands made available) were resolved.

The full record of excavated contexts is recorded in the context register and the strati-graphic matrix (Appendix 1). Detailed stratigraphic descriptions are found in the groups and sub-groups text (Appendix 2). The context register maybe viewed in the EAPOD (Eachtra Archaeological Projects office database) in the accompanying CD.

Drumroe-e3773

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7 Excavation resultsA Bronze Age structure, a cluster of pits and medieval ditches were excavated at Drumroe 1 (Figure 5 and Plate 1).

Habitation AreaThe remnants of a house, Structure A, were identified in the eastern portion of the site. The structure was defined by an arc of posts, a porch and two slot trenches. Only the east-ern portion or front of the structure survived. The reason for this is unclear. The ground surface was level, the topsoil was a similar depth across the site and the subsoil showed no signs of significant alterations from activities such as deep ploughing, furrows or land reclamation. The rear of the structure may not have survived if the foundations had not pierced the subsoil, the basic elements of the structure may have been only been driven into the topsoil.

Structure AStructure A was located on the eastern edge of the site (Figure 6 and Plate 2). It was de-fined by two incomplete rings of post-holes and slot trenches, the inner ring was concen-tric with the outer. No trace of the rear (western and northern sections) of the structure

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survived. The estimated internal diameter of the structure measured 7 m and had an in-ternal floor space of c. 38sq m (Area = π x R2).

The inner ring comprised six postholes (C.112, C.188, C.171, C.173, C.198, C.123 and C.112). Three of the posts (C.198, C.123 and C.112) were located on the northern circuit of the inner ring and three (C.173, C.171 and C.188) on the southern. The interval be-tween the posts was reasonably regular with the exception of one posthole (C.112) which was located on the northern circuit 4.8 m northwest of post C.123. Stake-hole C.200 was located adjacent to post C.198 and stake-holes C.172 and C.206 adjacent to post C.171.

The outer ring comprised two slot trenches (C.180 and C.201) which measured more than 2.5 m in length. One post-hole C.209 was located in the slot trench C.180 and two post-holes (C.185 and C.187) in the slot trench C.201. Each of the slot trenches termi-nated in a post-hole (C.104 and C.116 respectively) which formed the western end of the entrance porch. Post-holes (C.128 and C.150) which were located 1.7 m to the east formed

Figure6: Post-excavationplanofStructureAatDrumroe�

Structure

3

180

46

201

208

66

96

198

48

112

116

128

171

104

124

150

188

123

173

142

209

162

164193

204

161

185

172

200

206

191

165

187

195

±

0 2.5 m


14

the eastern end of the entrance porch. The porch measured c. 1 m in width by 1.7 m in length and faced directly east. Three other features, a post-hole (C.142) located on the northern side of the porch and two stake-holes (C.193 and C.195) located on the southern side, were associated with the porch.

Structure AContext Dimensions (mm)C.188 0.26 X 0.2 X 0.2C.171 0.3 X 0.26 X 0.3C.173 0.21 X 0.19 X 0.15C.198 0.26 X 0.23 X 0.23C.123 0.17 X 0.15 X 0.30C.112 0.32 X 0.24 X 0.27C.185 (in slot trench C.180) 0.08 X 0.06 X 0.12C.187 (in slot trench C.180) 0.25 X 0.2 X 0.21C.209 (in slot trench C.201) 0.2 X 0.18 X 0.17C.104 (Porch) 0.26 X 0.25 X 0.31C.116 (Porch) 0.29 X 0.2 X 0.4C.128(Porch) 0.33 X 0.28 X 0.3C.150(Porch) 0.26 X 0.26 X 0.36C.180 (slot trench) 2.8 X 0.15 X 0.12C.201 (slot trench) 2.7 X 0.18 X 0.12

Table1:DimensionsoffeaturesassociatedwithStructureA

Plate2: PostexcavationofStructureAatDrumroelookingwest�

Drumroe-e3773

15


A post-hole C.124 and a stake-hole C.191 were located on the exterior of the slot trench C.201 2 m south of the porch.

A radiocarbon date from the external slot trench (C.201) returned a Late Bronze Age date of cal BC 899-815 (UB-15085) from alder charcoal.

Internal FeaturesTwo post holes (C.48 and C.66) and a pit (C.46) were located in the centre of the struc-ture (Plate 3). One of the postholes C.66 was located on the western edge of the pit and the other was located 0.5 m to the south. The pit measured 1 m in width by 0.33 m in depth and may have functioned as a hearth. The post-holes may have served a structural purpose associated with the roof or they may have been related to domestic activates (Figure 7).

A group of six stake-holes (C.161, C.162, C.164, C.165, C.204 and C.206) were lo-cated to the south of the hearth and may have formed, albeit a slightly irregular, internal screen or division. A small slot trench C.208 was located to the west of the screen.

The pit C.46 was sampled and returned an early medieval date of cal AD 681-778 (UB–15087).

Pits and stakeholesA widely dispersed group of sixteen pits (C.17, C.19, C.21, C.32, C.49, C.52, C.63, C.75, C.81, C.99, C.113, C.133, C.134, C.140, C.149 and C.153) and two stake-holes (C.82 and C.97) were recorded in the western portion of the site (see Figure 5). Small quantities of charred plant remains were recovered from six of the pits (C.17, C.21, C.52, C.75, C.81 and C.140). A relatively large portion of charred hazelnut shell fragments were retrieved from pits C.75 and C.81. Small amounts of cereal grains, oat and barley were also recov-ered. Three animal bones from a large mammal were recovered from pit C.21.

Three of the pits (C.49, C.63 and C.75) were located 24 m to the west of the structure. Pit C.75 was the largest of the three pits and the deepest of the pits recorded in the west-ern section of the site. A single stake-hole was located on the south-eastern edge of the pit.

Five of the pits (C.19, C.21, C.52, C.149 and C.153) were located in a north-south orientated line, spanning a distance of 12 m. Two of them C.21 and C.52 were located on either side of the ditch C.18, 4 m to the east of the eastern ditch terminal (Plate 4).

A large shallow pit C.134 was located 9 m to the north of the line of five pits on the northern edge of the area of excavation (Plate 5).

Three other pits (C.32, C.99 and C.113) were located on the southern side of ditch C.18. Two of them were small in size and could have been the base of post-holes. They were located within 1.5 m of one another and 7.5 m west of the third pit C.113.

Four pits were located at the eastern end of the site. Three (C.81, C.133 and C.140) were located on the western side of the ditch C.5 and one, C.17, on the eastern side. Pit C.17 was the largest of the pits recorded in this area (Figure 8).

An Iron Age date of cal BC 386–204 was returned from pit C.81 (UB–15044).

C.66

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Drumroe-e3773

17


Plate3: PostexcavationofStructurelookingeast,hearthC�46inforegroundatDrumroe�

Plate4: Post-excavationofpitC�21inDrumroe

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Drumroe-e3773

19


Field BoundariesThere were no extant field boundaries recorded within the area of excavation but a series of back filled field boundaries (C.3, C.4, C.5, C.18/C.53, C.41, C.50, C.105 and C.144) were recorded at Drumroe. The ditches were all broad U-shaped in plan. Four of the ditches (C.4, C.41, C.50 and C.144) were orientated north-south. They extended beyond the area of excavation to the south and north and were recorded in the field to the south by the geophysical survey (see figure 10). Ditch C.144 and C.41 formed two segments of one ditch, C.41 was the northern section and C.144 the southern section (Plate 6). There was a gap of 1 m between the terminals of the two segments of the ditch.

The ditch C.144 and C.41 were recut by ditches C.50 and C.4 respectively (Figure 9). The two latter ditches were orientated north-south and were located parallel to one another. There was a distance of c. 2m between them. A field bank was probably located in this intervening space but no trace of the bank was recorded.

Ditch C.18 and C.53 were orientated east-west and formed two segments of one ditch (Plate 7). They curved across the site and were not cut in the same straight manner as the modern ditches (C.3 and C.5) on site. They were probably associated with ditches C.41 and C.144 as the eastern terminal of ditch C.18 was located between the gap in ditch C.41 and C.144. The western terminal of the ditch C.18 was located 0.7 m from the ter-minal of ditch C.53. This gap was slightly staggered, that is to say that the terminals of the two segments extended beyond one another.

Plate5: Post-excavationofpitC�134inDrumroe�

C.70

C.72

C.71

C.53

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C.76 C.64

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Drumroe-e3773

21


Plate6: SectionofditchesC�4andC�41fromsouthatDrumroe�

Plate7: SectionoftheditchC�53lookingeast�


22

An early medieval date of cal AD 897–1017 (UB–15086) was returned from charcoal from a fill of ditch C.18.

Two of the ditches (C.3 and C.5) were orientated NE–SW (Plate 8). Ditch C.3 was located at the eastern end of the site and ditch C.5 at the western end, c. 50 m apart. Frag-ments of clay pipe stems were recorded in the ditch fills. Ditch C.5 was marked on the first edition of the Ordnance Survey map OF 47.

Context Dimensions (m) (l x w x d) Orientation Associated with PeriodC.3 23 x 2.4 x 0.6 NE-SW C.5 ModernC.4 29.7 x 1.7 x 0.54 N-S C.41, C.50 and

C.144Late medieval?

C.5 43.5 x 1.7 x 0.65 NE-SW C.3 and C.105 ModernC.18 30 x 0.89 x 0.32 E-W C.53 Early

medieval?C.41 20 x 0.75 x 0.3 N-S C.4, C.50 and

C.144Late medieval?

C.50 32 x 0.97 x 0.34 N-S C.4, C.41 and C.144

Late medieval?

C.53 35 x 1.3 x 0.5 E-W C.18 Early medieval?

C.105 18 x 0.85 x 0.45 N-S C.5 Modern C.144 6 x 1.01 x 0.47 N-S C.4, C.41 and

C.50Late medieval?

Table2Dimensionsoftheditcheswithintheareaofexcavation

Plate8: SectionoftheditchC�5lookingwest�

Drumroe-e3773

23


The earlier ditches were slightly curved in form in comparison to the straighter mod-ern ditches, some of which were parallel to one another with space between for an inter-vening bank.

Lithic artefactsThe lithic artefacts were examined by Farina Sternke (Appendix 4). A flint convex end scraper (E3773:1:2) (Plate 9) were recovered from the topsoil. The assemblage dates to the Late Neolithic or Early Bronze Age period.

Bone remainsThe bone samples were examined by Margaret McCarty (Appendix 5). Three bone frag-ments were recovered from one of the pits C.21. The bones belonged to a large-sized animal such as cattle or horse.

Plant remainsThe plant remains were examined by Penny Johnston (Appendix 6). The cereals from

this site were identified as barley (3 grains were recovered) and a single grain each of emmer wheat and oat. Most of the cereals were not identifiable to type because of the poor state of preservation of the assemblage. Hazelnut shell fragments were found in the majority of the samples, nine samples in total. Tiny amounts of plant remains, mostly hazelnut shell fragments, and indeterminate cereal grains and one grain of emmer wheat

Plate9: ConvexEndScraper(E3773:1:2)


24

were recovered from five contexts (C.46, C.104, C.112, C.180 and C.198) associated with the

house. This suggests that only small-scale domestic debris was charred at the house.

Charcoal The charcoal was examined by Mary Dillon in advance of radiocarbon dating.

Radiocarbon datesRadiocarbon analysis was carried out by the 14 Chrono Centre in Queen’s University Belfast. Dates were calibrated using Calib Rev5.0.2 (©1986-2005 M.Stuiver & P.J. Re-imer) and in conjunction with Stuiver & Reimer 1993 and Reimer et al. 2004.

Lab no. Context Material Un-calibrated date

δ 13 C Calibrated BC 2–sigma dates

Period

UB–15044

C.85 Hazel charcoal from pit C.81

2230 +/- 27 -28.1 cal BC 386-343 325-204

Late Bronze Age/Iron age

UB–15085

C.202 Alder charcoal from slot trench C.201 Structure A

2708 +/ - 18 -25.2 cal BC 899-815 Late Bronze Age

UB–15086

C.33 Charcoal (Hazel) from ditch C.18

1074 +/ - 21 -27.3 cal AD 897-922 942-1017

Early medieval period

UB–15087

C.61 Charcoal (Prunus) from pit C.46

1259 +/- 17 -29.3 cal AD 681-778 Early medieval period

Table3:RadiocarbondatesfromDrumroe

Geophysical TestingSome geophysical testing, a magnetic gradiometer survey and a magnetic susceptibil-ity survey, was undertaken by Earthsound Archaeological Geophysics (Appendix 7) at Drumroe. The work was undertaken in the field to the south which bordered the Lands Made Available (Figure 10). A number of ditches were detected across the survey area. Some of the ditches represent a continuation of modern north-south field boundaries. The edge of the probable zone of archaeological activity was also established with the detection of an arcing enclosure ditch, which was broadly aligned east-west. A number of single and interconnecting ditches were also detected which may be archaeological or agricultural in origin.

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71

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71

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181640

181640

181680

181680

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Drumroe-e3773

25


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26

8 DiscussionExcavations at Drumroe revealed an area of settlement that comprised one structure that was dated to the Later Bronze Age. In addition to the structure, a group of pits and a series of field boundaries were recorded in the area of the excavation.

Bronze Age Settlement siteThe partial remnants of a Late Bronze Age structure were located in the southeastern corner of the site. The structure was defined by two incomplete rings, which constituted about two thirds of the structure, the rear or western section of the structure had not survived. The inner ring comprised six post-holes. The outer ring comprised two slot trenches. A porch formed by four post-holes, two of which were located in the terminals of the slot trenches, faced east and extended beyond the outer ring of the structure.

A pit, which was interpreted as a hearth and two associated postholes were located in the interior of the structure. Charcoal from the base of the hearth was dated to the early medieval period. Two scenarios are possible either the hearth was not associated with the structure, despite the apparent central location in the interior of Structure A or there was a problem with the charcoal.

There are two main hypotheses relating to the construction of the houses. Firstly, that an internal ring of posts supported the roof and immediately outside this a clay wall was built. No evidence for the clay wall, except for the empty space, survived. Directly outside the clay wall further roof support was offered by external support posts and associated slot trenches. The relationship between the external and internal posts may indicate the location of the wall top cross beams. The second hypothesis is that a clay wall was built outside and against the inner ring of posts which formed part of a wattle screen and that this wall ran along the line of the outer ring of posts and pits.

A recent survey of Bronze Age houses in southern Ireland lists a total of 41 Bronze Age sites where 81 individual structures have been recorded (Doody 2007, 86–7). How-ever, surveys are quickly out of date at the moment, since development-led archaeology has resulted in an explosion of Bronze Age archaeology (Bruck 2009a, xvi). The excava-tion of ten Bronze Age houses on the route of the N7 Castletown to Nenagh will further increase this number (Figure 11). Radiocarbon dates have been obtained for eight of the ten structures on the N7 from the townlands of Clash, Castleroan, Derrybane, Drum-baun, Drumroe and Moatquarter.

There is a diversity in house size, internal pattern and construction materials. In Brit-ain there appears to be a number of regionally distinct house styles (Doody 2007, 97) but there is no established evidence for regional variation amongst Irish examples as yet. However, the discovery of axial symmetry in several houses excavated in Tipperary and North Cork has been noted (Tierney and Johnston 2009, 105). A similar phenomenon has also been identified in Britain (Guilbert 1982, 68– 9; Brück 1999). Three of the round post-built structures, Structure 1 in Derrybane and two in Drumbaun, excavated on the N7 were constructed along the principle of axial symmetry. This means that house

0 10 m

Drumroe

Moatquarter

DrumbaunStructure A

DrumbaunStructure B

CastleroanStructure A Castleroan

Structure B

Derrybane 2Structure 1

Derrybane 2Structure 2

±

Hearth

Drumroe-e3773

27


Figure11:Post-excavationplansofeightoftheBronzeAgehousesontheN7CastletowntoNenagh�


28

was arranged on an axis between the entrance and a post-hole directly opposite it, two post-holes flank the entrance and the remaining post-holes have a corresponding partner at either side of the axis. The distance between the post-holes on either side of the axis is roughly the same (Tierney and Johnston ibid). Three other incomplete structures may have originally been constructed along the same principles.

Site Name E No. Structure Calibrated BC 2-sigma dates No of dates PeriodClash E3660 Structure 1 1111-920 and 895-800 2 MBA-

LBACastleroan E3909 Structure A 1249-1016 1 MBACastleroan E3909 Structure B 1011-914 1 LBADerrybane E3591 Structure 1 741-406 and 833-797 2 LBADerrybane E3591 Structure 2 794-550 1 LBADerrybane E3591 Structure 3 1929-1773 1 EBADrumbaun E3912 Structure A 1436-1316 1 MBADrumbaun E3912 Structure B 1520-1442 1 MBADrumroe E3773 Structure 1 895-815 1 LBAMoatquarter E3910 Structure 1 1495-1321, 1432-1316 and 1429-1315 3 MBA

Table4:RadiocarbondatesforBronzeAgestructuresontherouteoftheN7�

Three of the round post-built structures, the two in Drumbaun, and one in Derry-bane excavated on the N7 were constructed along the principle of axial symmetry. This means that house was arranged on an axis between the entrance and a post-hole directly opposite it, two post-holes flank the entrance and the remaining post-holes have a corre-sponding partner at either side of the axis. The distance between the post-holes on either side of the axis is roughly the same (Tierney and Johnston ibid). Three other incomplete structures, may have originally been constructed along the same principles.

Internal hearths were recorded in four of the structures illustrated in Figure 11, in Structure A Castleroan, Structure B Drumbaun, Structure 1 Derrybane 2 and Moat-quarter and a possible hearth in Structure B Castleroan. Hearth-side furniture including stakes which formed tripods, were associated with the internal hearths in Derrybane 2 and Moatquarter.

The front section of the house at Clash, Drumroe and Structure B Castleroan was recorded but the no trace of the rear had survived. No evidence of definite central roof support posts were recorded in any of the structures. Internal divisions were recorded in both structures in Drumbaun, in one of the structures in Castleroan and evidence of multi screens or phases of screens were recorded at Moatquarter.

External slot trenches, which followed the curve of the inner ring of posts, were re-corded at both Structures 1 and 2 in Drumbaun and at Drumroe. These extended from one or both sides of the entrance posts for lengths of upto 6 m, and have been termed ‘eye-brows’. They may have functioned as drip gullies for water from the roof or they may have been part of a revetment for the outer face of a clay wall which would have been po-sitioned between the inner ring of posts and the slot trench itself. In the majority of cases the slot trench tails off and was not recorded at the rear of the house. An exception was recorded at Moatquarter where the slot trench encircled the rear rather than the entrance

Drumroe-e3773

29


to the house. No direct evidence for clay walls were recorded at any of the Bronze Age set-tlement sites on the N7 but clay walls do not generally leave any trace in the archaeologi-cal record. The average space between the inner and outer ring at Structure A Castleroan was 1.4 m. The average space between the inner ring of posts and the slot trenches at Drumbaun was between 0.9-1.4 m. The distance was narrower, 0.5 m at Drumroe.

The limited recovery of charred plant remains from Bronze Age house sites was quite common, along the route of the N7 Castletown to Nenagh road scheme. Small assem-blages were recovered from Bronze Age settlement sites at Castleroan, Moatquarter and Drumroe. The small quantities of plant remains from these sites probably represent piece-meal and small-scale charring during cooking and domestic activity.

Iron Age activityA widely dispersed group of 16 pits were located at the western end of the site. The pits were small and shallow in depth. Small amounts of plant remains including charred ha-zelnut shell fragments were recovered from six of the pits. The majority of the hazelnut shell fragments came from pits C.75 and C.81, pits located on the eastern and western periphery of the group respectively. Three animal bones, the only bones recovered from the entire area of excavation, were also recovered from one of the pits. One Iron Age date was returned from a pit C.81. It is likely on the basis of the similarity of the type of pits and the fills, which included small amounts of charred plant remains, that all of the pits at the eastern end of the site are contemporary with the Iron Age phase of activity.

Evidence of Iron Age activity was also recorded at Castleroan E3909 a site located c. 1 km to the north, two pits at the site were dated to the Iron Age. No other evidence of the Iron Age was recorded on any of the sites on the route of the N7 Castletown to Nenagh (Contract 1).

Medieval activityTwo early medieval radiocarbon dates were returned from features at Drumroe. Char-coal from the basal fill of a pit or hearth, which was located within a Late Bronze Age structure, was dated to the 7th/8th centuries AD. The date from the pit is problematic as the pit (hearth) did appear to be associated with the Late Bronze Age structure. No other features were dated to this period.

A later medieval date, from the 9th/10th century AD, was returned from a fill of one of the ditches C.18. The ditch was one of a series of field boundaries excavated at Drumroe. They formed the boundaries of relict field systems. At least three phases of ditches were recorded and a broad typology of ditches can be associated with the three phases. The two earliest ditches (C.18/C.53 and C.41/C.144) were broad U-shaped and shallow in plan and formed the southern and eastern side of an enclosure or field. Gaps, were recorded between the segments of both ditches, they were less that 1 m in width. The small gaps between the segments of ditches may be interpreted as an entryway into a field. The ma-jority of them were less than 1 m in width and this may indicate that they were for human entry not for livestock. No post-holes or other structural evidence was recorded next to


30

any of the gaps but some form of a gate could have existed. Where the gap between the segments of a ditch was staggered the associated bank could have alternated from one side of the ditch to the other at this point.

The eastern circuit of the ditch was recut. The recut ditches (C.4 and C.50) were also broad U-shaped in plan but were straighter. They were parallel to one another and a bank must have existed in the intervening space.

Two modern field boundaries encompassed the earlier field system. The western ditch was marked on the first edition Ordnance Survey map (Sheet OF 47). The ditches were deeper and steeper than the earlier ones.

It would be incorrect to state with certainty, on the basis of a single radiocarbon date, that the primary phase of the ditches at Drumroe were medieval in date. But a number of other similar relict field boundaries were recorded at a few sites on the route of the N7 Castletown to Nenagh (Contract 1) and were dated or dated by association to the late medieval period. A late medieval enclosure and associated field systems 13th/14th were recorded at Killeisk E3587. A small number of field boundaries were recorded at Busher-stown E3661, they post-dated the annex associated with the 13th/14th century moated site and had gone out of use by the middle of the 19th century as they were not marked on the first edition Ordnance Survey map (Sheet TN 22). A series of field boundaries were also recorded at Drumbaun E3912. It is possible that these curving ditches enclosed an area of medieval iron-working although no radiocarbon date was obtained from any of the ditch fills.

Drumroe-e3773

31


9 ReferencesBruck, J. (2009a) Overview of findings, pp. xvi – xviii in McQuade, M., Molloy, B. and

Moriarty, C. In the Shadow of the Galtees. Archaeological excavations along the route of the N8 Cashel to Mitchelstown Road Scheme. Dublin, National Roads Authority.

Doody, M. (2007) Excavations at Curraghatoor, Co. Tipperary, University College Cork.

Farrelly, J., and O’Brien, C. (2002) Archaeological Inventory of County Tipperary Vol. 1 - North Tipperary, The Stationery Office Dublin.

Gardiner, M.J. and Radford,T. (1980) Soil Assocaitions of Ireland and Their Land Use Potential. Dublin, An Foras Talúntais.

Guilbery, G. (1982) ‘Post-ring symmetry in roundhouses at Moel y Gaer and some other sites in prehistoric Britain’, in P J Drury (ed), Structural Recognition: approaches to the interpretation of excavated remains of buildings, 67 – 86. British Archaeological Reports 110.

Lynch, L. (2010 forthcoming) Burial at Derrybane in the Bronze Age in Seanda, Issue 5, Dublin.

McLaughlin, M. and Conran, S. (2008) ‘The emerging Iron Age of South Munster’ in Seanda, Issue 3, 51-53. Dublin.

National Inventory of Architectural Heritage (2006) An Introduction to the Architectural Heritage of North Tipperary. Government of Ireland.

O’Conor, K.D. (1998) The Archaeology of Medieval Rural Settlement in Ireland, Discovery Programme Monographs No 3, Discovery Programme/Royal Irish Academy Dublin.

Reimer, P.J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Bertrand, C., Blackwell, P.G., Buck, C.E., Burr, G., Cutler, K.B., Damon, P.E., Edwards, R.L., Fairbanks, R.G., Friedrich, M., Guilderson, T.P., Hughen, K.A., Kromer, B., McCormac, F.G., Manning, S., Bronk Ramsey, C., Reimer, R.W., Remmele, S., Southon, J.R., Stuiver, M., Talamo, S., Taylor, F.W., van der Plicht, J. and Weyhenmeyer, C.E. (2004) ‘IntCal04 Terrestrial Radiocarbon Age Calibration, 0–26 Cal Kyr BP’, Radiocarbon 46, 1029-1058.

Stuiver, M., and Reimer, P.J. (1993) ‘Extended (super 14) C data base and revised CALIB 3.0 (super 14) C age calibration program’, Radiocarbon 35, 215-230.


32

Stout, M. (1997) The Irish Ringfort. Dublin, Four Courts Press.

Taylor, K. (2008) ‘At home and on the road: two Iron Age sites in County Tipperary’ in Seanda, Issue 3, 54-55. Dublin.

Tierney, J. and Johnston, P. (2009) No Corners, Prehistoric roundhouses on the N8 and N7 in counties Cork, Tipperary and Offaly in Dining and Dwelling Archaeology and the National Roads Authority Monograph Series No. 6. 99-108 National Roads Authority, Dublin.

Woodman, P.C. (2000) ‘Hammers and Shoeboxes: New Agendas for Prehistory’., pp. 1 -10 in Desmond, A., Johnson, G., McCarthy, M., Sheehan, J. and Shee Twohig, E. New Agendas in Irish Prehistory. Papers in commemoration of Liz Anderson. Bray, Wordwell.

Drumroe-e3773

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Appendix 1 Stratigraphic Index

Please see attached CD.


34

App

endi

x 2

Site

Mat

rix

Drumroe-e3773

35



36

Drumroe-e3773

37


Appendix 3 Groups and subgroupsGroup No.

Description Subgroup No. Description Context No.

1 Natural Deposits

TopsoilSubsoil

C.1C.2

2 Bronze Age House

Subgroup 2a

Subgroups 2b Subgroup 2c

Subgroup 2d

Porch

Arc of postholes

Drip gullies

Internal and as-sociated features

C.104, C.116, C.128 and C.150

C.123, C.198, C.173, C.171, C.188, C.185, C.187, C.209, C.112

C.180 and C.201

C.66, C.46, C.96, C.200, C.142, C.173, C.172, C.171, C.206, C.165, C.164, C.188, C.162, C.161, C.204, C.208

3 Pits and stakeholes

C.17, C.19, C.21, C.32, C.49, C.52, C.75, C.81, C.99, C.113, C.133, C.134, C.140, C.149, C.153, C.97 and C.82.

4 Ditches Subgroup 2a

Subgroups 2b

Medieval field boundariesModern

C.4, C.18, C.41, C.50, C.53, C.105 and C.144

C.3, C.55 Non-Archae-

ologicalC.90, C.91, C.92, C.93, C.100, C.102, C.103, C.117, C.120, C.122, C.125, C.126, C.130, C.131, C.132, C.154, C.155, C.156, C.157, C.158, C.166, C.167, C.168, C.169, C.170, C.174, C.175, C.160 and C.163.

Group 1 Natural DepositsThis group describes the natural geological deposits identified across the area of excavation.

Topsoil C.1 The topsoil was covering the archaeological features on the site. The topsoil was dark

black brown sand silt.

Subsoil C.2The subsoil was mid red yellow firm sand clay. This is the natural subsoil which occurs

under the features and was found across the site.

Group 2 Bronze Age HouseThe Bronze Age Structure measured 7m in diameter and comprised an arc of internal postholes, an external drip gully, a porch facing east and associated internal features. A date from the drip gully produced an uncalibrated BP date of 2708 +/ - 18. Only the eastern portion of the structure survived. The northern, southern and western structural elements of the building were not present.


38

Subgroup 2a PorchThe porch consisted of four postholes C.104, C.116, C.128 and C.150. The porch meas-ured 1.8m long (east west) and 1m wide (north south) and was orientated east west.

Context Dimen-sions (m) within area of excavation

Depth (m)

Shape in plan

Orienta-tion

Sides Base Filled with

C.104 0.26m X 0.25m

0.31m Circular N-S Gentle and smooth

Circular and concave

C.101

C.116 0.29m X 0.2m 0.4m Circular N-S Vertical and irregular


C.114

C.128 0.33m X 0.28m

0.3m Circular E-W Vertical and convex

Sub-circular and flat

C.127

C.150 0.26m X 0.26m

0.36m Circular N-S Vertical and concave


C.148

Subgroups 2b Arc of postholesThe inner ring of the house comprised six postholes C.188, C.171, C.173, C.198, C.123 and C.112. Five of these postholes (C.188, C.171, C.173, C.198 and C.123) were located directly behind the drip gullies and form the eastern structural elements of the house. At the base of the drip gullies three postholes were excavated (C.185, C.187 and C.209). These postholes may have formed an element of an external wall. The posthole is C.112 is located 4 metres from the eastern wall and is an isolated posthole, however it may have formed part of the northern wall.


Depth (m)

Shape in plan

Orienta-tion


C.188 0.26m X 0.2m 0.2m Sub-circular

NE-SW Vertical and smooth

Sub-circular and tapered

C.189

C.171 0.3m X 0.26m 0.3m Circular E-W Steep and smooth


C.182

C.173 0.21m X 0.19m

0.15m Circular N-S Vertical and smooth

Sub-oval and flat

C.176

C.198 0.26m X 0.23m

0.23m Oval Vertical and smooth

Oval and concave

C.197

C.123 0.17m X 0.15m

0.30m Circular Vertical and dry


C.119

C.112 0.32m X 0.24m

0.27m Circular N-S Vertical and concave

Sub-rectangular and flat

C.109

C.185 0.08m X 0.06 0.12m Oval Vertical and smooth

Oval and rounded point

C.184

C.187 0.25m X 0.2m 0.21m Oval N-S Vertical and smooth

Oval and flat C.186

C.209 0.2m X 0.18m 0.17m Circular E-W Gentle and smooth


C.210

Drumroe-e3773

39


Subgroup 2c Drip gulliesTwo drip gullies (C.180 and C.201) were located perpendicular to the porch. These “eye-brows” may have formed an external wall. At the base of the drip gullies three postholes were excavated (C.185, C.187 and C.209).


Depth (m)

Shape in plan

Orienta-tion


C.180 2.7m X 0.15m 0.12m Curvi-linear

N-S Vertical and smooth

Curvi-linear and concave

C.151/179

C.201 2.68m X 0.18m

0.12m Linear NE-SW Vertical and smooth

Linear and flat

C.202

Subgroup 2d Internal featuresA total of thirteen features were excavated within the confines of the structure (C.208, C.204, C.161, C.162, C.164, C.165, C.206, C.172, C.48, C.66, C.46, C.96 and C.200). Three external features (C.142, C.195 and C.193) are also included with this subgroup as they were located adjacent to the porch.

Con-text

Context type

Dimensions (m) within area of excavation

Depth (m)

Shape in plan

Orien-tation


C.208 Linear 1m X 0.26m 0.1m Linear NE-SW

Vertical and smooth

Linear and flat

C.207

C.204 Stakehole 0.07m X 0.06m

0.14m Circular Vertical and smooth

Circular and pointed

C.203

C.161 Stakehole 0.09m X 0.08 0.12m Circular Steep and smooth

Circular and tapered

C.177

C.162 Stakehole 0.1m X 0.1m 0.13m Circular N-S Steep and smooth

Tapered C.181

C.164 Stakehole 01m X 0.09m 0.18m Circular Steep and smooth


C.177

C.165 Stakehole 0.12m X 0.07 0.1m Circular N-S Steep and smooth


C.183

C.206 Stakehole 0.05m X 0.05 0.1m Circular N-S Vertical and smooth


C.205




C.190

C.48 Posthole 0.22m X 0.16m

0.2m Oval E-W Steep and smooth


C.51


0.27m Sub-circular

E-W Vertical and smooth


C.67 and C.68

C.46 Pit cut 1m X 0.8m 0.33m Oval N-S Moderate and smooth

Oval and concave

C47, C. 69, C.60 and C.61


0.24m Circular E-W Verti-cal and concave

Circular and flat

C.94


0.12m Oval N-S Vertical and smooth

Oval and pointed

C.199


40


0.2m Oval E-W Gentle and irregular

Oval and concave

C.139

C.195 Stakehole 0.07m X 0.06 0.11m Circular Vertical and smooth


C.196




C.194

Group 3 Pits Fifteen postholes and two stakeholes were identified across the area of excavation. These were C.17, C.19, C.21, C.32, C.49, C.52, C.63, C.75, C.81, C.99, C.113, C.133, C.134, C.140, C.149, C.153, stakehole C.97 and stakehole C.82. A radiocarbon date was re-trieved from the pit C.81 which gave an uncalibrated date BP of 2230 +/- 27. No correla-tion or affinity was assumed or noted between these features.

Con-text

Dimen-sions (m) within area of excavation

Depth (m)

Shape in plan

Orienta-tion


C.17 1.64m X 1.36m

0.23m Sub-rectan-gular

NE-SW Moderate and smooth


C.22, C.23 and C.24

C.19 1.2m X 0.94m 0.11m Oval E-W Moderate and irregular

Irregular and concave

C.26

C.21 0.84m X 0.67m

0.17m Oval E-W Steep and irregular

Oval and flat

C.35, C.36, C.37 and C. 38

C.32 0.5m X 0.46m 0.08m Sub-circular E-W Steep and smooth

C.62

C.49 0.5m X 0.48m 0.19m Oval N-S Steep and concave

Oval and concave

C.55, C.56 and C.57

C.52 0.7m X 0.6m 0.28m Sub-circular E-W Vertical and smooth

Irregular and concave

C.58

C.63 0.4m X 0.38 0.12m Sub-circular NW-SE Gradual to sharp

Sub-rectan-gular and concave

C.74

C.75 1.43m X 1.03m

0.38m Pear-shaped NE-SW Moderate and smooth

Pear shaped and concave

C.79, C. 80 and C.87

C.81 0.76m X 0.58m

0.25m Oval NW-SE Steep and concave

Oval and concave

C.84 and C.85

C.99 0.36m X 0.34m

0.14m Oval E-W Gentle and concave

Circular and undulating

C.20

C.113 0.84m X 0.61m

0.14m Oval N-S Gentle and concave

Oval and concave

C.115

C.134 1.4m X 1.27m 0.14m Sub-circular N-S Moderate and smooth

Sub circular and concave

C.143

C.140 0.7m X 0.62m 0.14m Sub-circular E-W Moderate and concave

Oval and concave

C.138 and C.141

C.149 0.62m X 0.53m

0.24 Circular E-W Gentle and irregular

Oval and concave

C.152

C.153 1.18m X 0.9m 0.27m Irregular N-S Moderate and irregular

Irregular and flat

C.159

C.97 0.1m X 0.1m 0.17m Circular N-S Vertical and smooth


C.98

C.82 0.10m X 0.08m

0.17m Circular NW-SE Vertical and smooth


C.83

Drumroe-e3773

41


Group 4 Ditches

Subgroup 4a medieval ditchesSeven ditches (C.4, C.18, C.41, C.50, C.53, C.105 and C.144) were recorded within area of excavation. A cluster of four ditches (C.4, C.41, C.50 and C.144) were located in the centre of the site and were parallel to each other and were orientated north south. The boundaries (C.18/C.53) were a possible medieval field boundary which measured between 0.89 – 1.3 m in width and between 0.32– 0.5 m in depth. It was c. 50 m long, extending beyond the area of the excavation to the west, and it was aligned east-west. An entrance was located roughly at the centre of the excavated portion of the ditch. This was approxi-mately 1 m wide, located between two ditch terminals. The entrance between the two terminals did not follow a straight line but was staggered and the pathway between the ditch terminals zig-zagged slightly. This may have ensured that animals stayed inside the field or enclosure that was surrounded by this boundary.

Subgroup 4b Modern ditchTwo possible modern ditches (C.5 and C.105) were located to the western extents of the site. The ditch C.5 was orientated northeast southwest, was recorded on the first edition maps and was truncated by the ditch C.105 which ran perpendicular to C.5. A field boundary (C.3) was located east of the Structure and is orientated northeast southwest.

Con-text

Dimen-sions (m) within area of excavation

Depth (m)

Shape in plan

Ori-enta-tion


C.3 23m X 2.4m 0.6m Linear NE-SW

Steep and smooth

Linear and flat C.10, C.11, C.12, C.13, C.69 and C.137

C.4 29.7m X 1.7m 0.54m Linear N-S Moderate stepped

Linear and flat C.14, C.15 and C.16

C.5 43.5m X 1.7m 0.65m Linear NE-SW

Steep and concave

Linear and concave

C.6, C.7, C. 8, C. 9,C. 29 and C.30

C.18 30m X 0.89m 0.32m Linear E-W Moderate and convex

Sub-rectangular and convex

C.33 and C. 34

C.41 20m X 0.75m 0.3m Linear N-S Moderate and convex

Sub-rectangular and flat

C.42, C.43, C, 44, C. 45, C.54, C.110 and C.111.

C.50 32m X 0.97m 0.34m Linear N-S Steep and smooth

Sub-rectangular and concave

C.64, C.65, C.76, C.77 and C. 78

C.53 35m X 1.3m 0.5m Linear E-W Moder-ate and concave

Linear and irregular

C.70, C.71 and C.72

C.105 18m X 0.85m 0.45m Linear N-S Steep and concave

Linear and concave

C.106, C.107 and C.108

C.144 6m X 1.01m 0.47 Linear N-S Moderate and smooth

Linear and concave

C.145, C.146 and C.147


42

Group 5 Non-Archaeological featuresIn total 29 features were recorded as being archaeological however they were later deemed to be non archaeological. A context number was assigned to each feature and due to a va-riety of reasons 29 features were deemed non archaeological. These were C.90, C.91, C.92, C.93, C.100, C.102, C.103, C.117, C.120, C.122, C.125, C.126, C.130, C.131, C.132, C.154, C.155, C.156, C.157, C.158, C.166, C.167, C.168, C.169, C.170, C.174, C.175, C.160 and C.163.

Drumroe-e3773

43


Appendix 4 Lithics report

by Farina Sternke

IntroductionOne lithic find from the archaeological excavation of a prehistoric site at Drumroe 1, Co. Offaly was presented for analysis (Table 1). The find is associated with a Bronze Age house, a group of pits and a number of medieval field boundaries.

Find

Num

ber

Con

text

Mat

eria

l

Type

Cor

tex

Con

ditio

n

Leng

th (m

m)

Wid

th (m

m)

Thi

ckn.

(mm

)

Com

plet

e

Ret

ouch

E3773:1:2 1 Flint Re-touched Artefact

No Patinated 32 20 9 Yes left edge and distal di-rect abrupt, right edge direct semiabrupt

Table1CompositionoftheLithicAssemblagefromDrumroe1(E3773)

MethodologyAll lithic artefacts are examined visually and catalogued using Microsoft Excel. The fol-lowing details are recorded for each artefact which measures at least 2 cm in length or width: context information, raw material type, artefact type, the presence of cortex, arte-fact condition, length, with and thickness measurements, fragmentation and the type of retouch (where applicable). The technological criteria recorded are based on the terminol-ogy and technology presented in Inizan et al. 1999. The general typological and morpho-logical classifications are based on Woodman et al. 2006. Struck lithics smaller than 2 cm are classed as debitage and not analysed further, unless they represent pieces of techno-logical or typological significance, e.g. cores etc. The same is done with natural chunks.

QuantificationThe lithic (E3773:1:2) is a worked piece of flint.

ProvenanceThe artefact was recovered from the topsoil.

Condition:The lithic survives in patinated, complete condition.


44

Technology/Morphology: The artefact is a convex end scraper which measures 32 mm long, 20 mm wide and 9 mm thick.

Dating:The artefact dates to the Late Neolithic/Early Bronze Age period.

ConservationLithics do not require specific conservation, but should be stored in a dry, stable environ-ment. Preferably, each lithic should be bagged separately and contact with other lithics should be avoided, so as to prevent damage and breakage, in particular edge damage which could later be misinterpreted as retouch. Larger and heavier items are best kept in individual boxes to avoid crushing of smaller assemblage pieces.

SummaryThe lithic find from the archaeological excavation at Drumroe 1, Co. Offaly is a flint convex end scraper which dates to the Late Neolithic/Early Bronze Age period.

This site makes a minor contribution to the evidence for prehistoric settlement and land use in Co. Offaly.

BibliographyInizan, M.-L., M. Reduron-Ballinger, H. Roche and J. Tixier 1999. Technology and

Terminology of Knapped Stone 5. CREP, Nanterre.

Woodman, P. C., Finlay, N. and E. Anderson, 2006. The Archaeology of a Collection: The Keiller-Knowles Collection of the National Museum of Ireland. National Museum of Ireland Monograph Series 2. Wordwell, Bray.

Drumroe-e3773

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Appendix 5 Animal bone report

The excavations at Drumroe 1 revealed a group of pits that were found close to a medi-eval field boundary. One of these was dated to the Iron Age, the remainder including the bone-producing pit (C21) could be Iron Age or early medieval in date. Just three bones were found in the fill (C38) of the pit and none of these are diagnostic to species. They are sufficiently large and thick-walled to indicate that they belong to a large-sized animal such as cattle or horse.


46

Appendix 6 Plant remains report

By Penny Johnston

IntroductionThis report details the results of plant remains analysis from Drumroe, Co. Tipperary (E3773). The site comprised a Bronze Age house, a group of pits, a number of medieval field boundaries and modern field boundaries.

MethodologyThe samples were collected on site as bulk soil and were processed using machine-as-sisted floatation (following guidelines in Pearsall 2000). The floating material (or ‘flot’) from each sample was collected in a stack of geological sieves (the smallest mesh size was 250mm). When all the carbonised material was collected the flot was then air-dried in paper-lined drying trays prior to storage in airtight plastic bags. The samples were scanned under low-powered magnification (x 10 to x 40) using a binocular microscope. Nomen-clature and taxonomic order follows Stace (1997).

ResultsThe results of preliminary scanning are presented in Table 1 at the end of this report. A total of 33 samples were scanned and plant remains were present in 14 of the samples. The identifications are presented in Table 2.

Hazelnut shell fragments were found in the majority of the samples, nine samples in total. A total of 92 fragments were counted. These plant remains are frequent finds in Irish archaeological sites. Their frequency is due partly to the fact that they were collected, eaten and used frequently in the past and also to the taphonomic factors that govern the preservation of hazelnut shells (see discussion in Monk 2000, 74 – 75).

The cereals from this site were identified as barley (3 grains were recovered) and a single grain each of emmer wheat and oat. Most of the cereals from this assemblage were not identifiable to type (labelled as ‘ceralia’). A total of eight grains were categorised in this manner. It was not possible to identify these grains to type because of the poor state of preservation of the assemblage from Drumroe. It is impossible, within the context of this small assemblage, to judge the relative importance of each cereal type found.

A group of samples with seeds were taken from the round house that was excavated at Drumroe. These were taken from the post-holes C.104 (C.101, S.63), C.112 (C.109, S.71) and C.198 (C.197, S.94), from the ditch C.46 (C.60, S.38) and the slot trench C.180 (C.179, S.90). This was a tiny assemblage of plant remains, including 5 fragments of hazelnut shell fragments, a single grain of emmer wheat and two unidentifiable cereal grains. This suggests that only small-scale domestic debris was charred at the house. The results from the round house excavated at Moatquarter, also found along the route of the N7 Castletown to Nenagh, were similarly sparse (Johnston 2010).

Drumroe-e3773

47


The recovery of emmer wheat is interesting since barley is often the major cereal type recovered from Bronze Age sites, for example, only small quantities of emmer wheat were recovered from Bronze Age sites excavated along the route of the new N8 Cashel to Mitchelstown road (Halwas 2009, 263–266). In a study of material from the gas pipeline to the west emmer wheat was found particularly in the earlier part of the Bronze Age, with barley becoming particularly more common as the Bronze Age progressed (Johnston 2007, 73). The absence of barley from the Drumroe round house is not the usual pattern discovered from Irish Bronze Age site, however, the assemblage from this part of the site is so small it is not possible to say whether this is truly representative of the agrarian economy as practised at this site or not.

Another group of samples were taken from pits in the central and western area of the excavation at Drumroe: C.140 (C.141, S.11), C.21 (C.36, S.23), C.52 (C.58, S.35), C.75 (C.80, S.53), C.81 (C.85, S.56) and C.17 (C.114, S.70). These pits associated with habita-tion of the site but their original function is unknown. The plant remains from these pits included a relatively large portion of charred hazelnut shell fragments (82 fragments in total, most retrieved from pit C.81). There were also a small cereal grains, where identifi-able these were oat and barley. A single weed seed was recovered from the fills of these pits, identified as a seed from the knotgrass/dock family, a common weed of arable fields and waste ground.

Plant remains were also recovered in small quantities from the fills of ditches also excavated at Drumroe. These ditches were significantly different from the later, post-medieval ditches that truncated activity at the site. It is possible that they date to the medieval period. The plant remains material from these features was very limited, only hazelnut shell fragments and an indeterminate cereal grain were found.

ReferencesHalwas, S. (2009) ‘Macro-plant remains’, pp. 262–275 in McQuade, M., Molloy, B.

and Moriarty, C. In the Shadow of the Galtees. Archaeological excavations along the N8 Cashel to Mitchelstown Road Scheme. Dublin, National Roads Authority.

Johnston, P. (2010) Analysis of the plant remaisn from Moatquarter, Co. Tipperary (E3910). Unpublished technical report for Eachtra Archaeological Projects.

Johnston, P. (2007) ‘Analysis of carabonised plant remains’, pp. 70 – 79 in Grogan, E., O’Donnell, L. and Johnston, P. The Bronze Age Landscapes of the Gas Pipeline to the West. Bray, Wordwell.

Monk, M. (2000) ‘Seeds and soils of discontent,’ pp. 67-87 in A. Desmond, G. Johnson, M. McCarthy, J. Sheehan and E. Shee Twohig (eds.) New Agendas in Irish prehistory. Bray, Wordwell.


48

Pearsall, D. (2000) Paleoethnobotany: a Handbook of Procedures. New York, Academic Press.

Stace, C. A. (1997) New Flora of the British Isles. (2nd edition) Cambridge, Cambridge University Press.

Sample Context Charcoal Charred seeds % scanned

10 15 L A 10011 16 L A 10011 141 M L 10013 23 L A 10020 33 L L 10021 34 L A 10023 36 L L 10030 51 L A 10035 58 L L 10038 60 L L 10039 61 L A 10043 67 L A 10046 71 L A 10047 72 L L 10051 78 L A 10053 80 M-H M 10056 85 M-H M 10063 101 H L 10066 107 L A 10067 108 L A 10070 114 H L 10071 109 L L 10075 121 L A 10076 127 L A 10083 148 M A 10085 146 L L 10086 147 L A 10089 159 L A 10090 179 M L 10091 176 L A 10092 182 L A 10094 197 L L 10095 202 M-H A 100

A=Absent,L=Low,M=MediumandH=HighTable1:ScannedsamplesfromDrumroe,Co�Tipperary(E3773)

Drumroe-e3773

49


Cut

no.

140

1821

5246

5375

8110

417

112

144

180

198

Con

text

141

3336

5860

7280

8510

111

410

914

617

919

7Sa

mpl

e

11

2023

3538

4753

5663

7071

8590

94H

azel

nut s

hell

fragm

ents

(Cor

ylus a

vella

na L

.)

42

1

131

492

1

1In

dete

rmin

ate s

eeds

from

the K

notg

rass

fam

ily

(Pol

ygon

acea

e)

1

Oat

gra

ins (

Aven

a L.

spec

ies)

1

Barle

y gr

ains

(Hor

deum

vul

gare

L.)

1

2

Emm

er w

heat

(Trit

icum

dico

ccum

L.)

two

seed

ed g

rain

1

Inde

term

inat

e cer

eal g

rain

s (C

eral

ia)

21

12

11

Inde

term

inat

e gra

ss se

eds (

Poac

eae)

1

Tabl

e2:

Iden

tified

see

dsfr

omD

rum

roe,

Co�

Tip

pera

ry(E

3773

)


50

Appendix 7 Geophysics report

By Earthsound Archaeological Geophysics

Introduction to the Sites Earthsound Archaeological Geophysics were commissioned by Eachtra Archaeological Projects to execute a series of geophysical surveys over pre-selected sites located outside the C.P.O. boundary of the new N7 Road Scheme. The survey areas were located adjacent to sites containing archaeological remains that were excavated within the C.P.O. boundary and extend beyond it.

The new N7 road development extends from the eastern edge of the present N7 Nenagh Bypass and ties into the M7 / M8 Portlaoise-Castletown Scheme. The new de-velopment terminates south of Borris-in-Ossory. The scheme in total covers a length of 35 km and the work undertaken for this report comprised of land adjacent to Contract 1 (Clashnevin to Castleroan), a 17.1 km section of the road located on the western half of the overall development.

The bedrock geology along the scheme consists of a mixture of greywacke, siltstone, sandstone and mudstone all of which are suitable for magnetic susceptibility and mag-netic gradiometer geophysical surveys. However, the majority of archaeological features were magnetically very weak, which reflects a poor contrast between the fill of cut mate-rials and the parent geology. Magnetic susceptibility data were also generally very weak.

Permissions to undertake the geophysical surveys were obtained from the Department of the Environment, Heritage and Local Government (License R179). The geophysical survey was requested to assess the extent of the archaeological remains located outside the C.P.O. boundary. All sites were assessed using magnetic gradiometer and magnetic susceptibility surveys with the exception of Drumbaun 2 where high vegetation prevented the use of the magnetic susceptibility meter.

DrumroeLocated within the townland of Drumroe, the northwest corner of the site (Figure 1) lies at Ordnance Survey of Ireland Irish National Grid (ING) Reference E205155 N181674, adjacent to Chainage 13970-14170. The survey area is located on the southern edge of the N7 C.P.O. boundary within land that is topographically high and rising to the east.

Fieldwork was conducted on the 4th

June 2008 in hot and dry weather conditions that were suitable for the geophysical survey. The archaeological excavation at Drumroe 1 comprised a Bronze Age house, a group of pits and a number of medieval and modern field boundaries. The house measured 7 m in diameter and was truncated by the C.P.O. boundary (Eachtra 2008c).

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Aims & Objectives The geophysical survey was requested to assess the extent of the archaeological remains located outside the C.P.O. boundary. Specific objectives were to:

• Assess the extent and location of the archaeological remains associated with those uncovered in the excavation

• Determine the presence or absence other associated archaeological features A meth-odology was developed to allow multiple techniques to systematically investigate the site. Detailed magnetic gradiometer and magnetic susceptibility surveys were carried out within the survey area. These techniques have been used in commercial and research archaeological projects for many years and are considered the most appropriate techniques for a detailed investigation of the underlying archaeology (Clarke 1996, Scollar et al. 1990). Where possible, the use of multiple geophysical techniques allows a greater confidence to be placed in the interpretation of detected anomalies, which is especially useful on small sites such as this. Their combined application can be used to determine the geometry, compositional material and the extent of an archaeological target.

Methodology The fieldwork was carried out by J. Bonsall, D. Jones and H. Gimson of Earthsound Ar-chaeological Geophysics. A magnetic gradiometer survey was carried out using two Geoscan Research FM256 fluxgate gradiometers. Two pairs of sensors were mounted on a CF6 carry frame.

A magnetic susceptibility survey was carried out using a Bartington MS2 Magnetic Susceptibility meter and MS2D search loop interfaced with a Trimble Pro-XRS Differ-ential GPS.

A rectangular grid was laid out using a Trimble Pro-XRS Differential Global Position-ing System (see Technical Appendix 2), and divided in to 40 × 40 m sub-grids for the gradiometer survey.

Magnetic Gradiometer Survey The survey was undertaken along lines parallel to the sub-grid edges, walking approxi-mately south to north, starting in the southwest corner of each grid. Subsequent lines were surveyed in alternate directions (‘zigzag’).

Data were recorded using an FM256 at a spatial resolution of 1 m intervals between traverses and 0.25 m intervals along those lines. The instrument was positioned facing north, parallel to the Earth’s magnetic field, to allow increased geo-magnetic resolution.

The instrument was set to a recording sensitivity of 0.1 nT. Prior to the beginning of the survey and after the completion of every two sub-grids, the electronic and mechanical setup of the instrument were examined and calibrated as necessary over a common refer-ence point. The magnetic drift from zero was not logged.


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Data were collected automatically using an internal sample trigger while the opera-tor walked at a constant pace along the traverse. The data were stored in an internal data logger and downloaded to a field computer using Geoscan Research Geoplot v.3.00a software.

Data Processing

Preliminary Data Treatment The data were pre-processed in Geoplot 3.00. Spurious high intensity anomalies, com-monly statistical outliers, are referred to as geophysical ‘spikes’. In magnetic data, an ‘iron spike’ is a response to a buried ferrous object, often in the topsoil. Iron spikes are generally not removed in geophysical data; although often modern in origin, they can be indica-tive of archaeological material. The raw data contained some poorly matched sub-grids, caused by the internal drift of the fluxgate gradiometer and the gradual misalignment of the fluxgate sensors between calibration episodes. To compensate for this, a zero mean traverse (ZMT) function was employed. The use of ZMT alters data to adjust the mean of each traverse to zero by increasing or decreasing data as necessary. This alters the sta-tistical properties of the data to give a uniformly bipolar background, centred around zero. Post-ZMT plots were compared with raw data to analyse the potential removal of geophysical anomalies along the line of a traverse.

Further Processing No further processing functions were applied due to the high quality of the data collec-tion. A low pass Gaussian filter was applied, reducing the variability of the data whilst improving the visibility of weak archaeological features. This also had a smoothing effect on the data. A sine wave interpolation function was applied to provide a smooth, aestheti-cally pleasing image for presentation. For a given point x, the contribution of adjacent readings to the interpolated point is given by the function sinc (x) = sin πx/πx (Scollar 1990). This function is used as a sliding window along each transect, resulting in an inter-polated image, expanding the resolution of the data from 1 m x 0.25 m to 0.5 m x 0.125 m. This function was chosen as giving a clearer interpolated image than linear interpola-tion (which assumes a direct linear change between each point) or bicubic interpolation (taking the surrounding sixteen values into account).

Graphical Display

Pre-processed data are displayed in XY traceplot format in Figures 2, 7, 10, 15, and 20. An XY traceplot presents the data logged on each traverse as a single line with each succes-sive traverse incremented on the Y-axis to produce a stacked plot. The data have not been clipped at –3 and +3 nT. The main advantage of this display option is that the full range of data can be viewed, dependent on the clip, so that the ‘shape’ of individual anomalies can be discerned and potential archaeological anomalies differentiated from iron ‘spikes’.

Processed data are shown in Greyscale format in Figures 3, 8, 11, 16 and 21. The grey-scale plot presents data as pixels on a linear grey shaded scale, increasing or decreasing

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dependent on the values of the maximum and minimum clip. The magnetic gradiometer data have been clipped at –2 (white) and +2 nT (black). Data values beyond the clip limits are shown as ‘pure’ black or white. The main advantage of this display option is that the data can be viewed as a base map.

An interpretation plot is presented in Figures 4, 9, 12, 17 and 22.

Magnetic Susceptibility Survey A geophysical grid baseline was not established for the Magnetic Susceptibility survey; a Differential Global Positioning System (DGPS) data logger, a Trimble TSC1, displayed a graphical representation of the survey area, with traverses spaced every 5 m. The graphi-cal representation was utilised by the geophysicists to navigate and collect data points at predetermined intervals.

The topsoil volume magnetic susceptibility survey was undertaken along lines parallel to the survey grids, walking approximately south to north. Subsequent lines were sur-veyed in alternate directions (‘zigzag’). Data were recorded at a spatial resolution of 5m intervals between traverses and 5m intervals along those lines.

The MS2 was set to a recording sensitivity of 1 SI unit to obtain (infinite) volume specific magnetic susceptibility (Volume MS or κ). When measured in SI units, the data is expressed as 1 x 10-5 κ. The MS-DGPS recorded northing and easting within the Irish National Grid to a minimum accuracy of ±1 m, and altitude to an accuracy of ±2 m.

Prior to surveying each survey station, the MS2 was calibrated according to the man-ufacturers guidelines, by ‘zeroing’ whilst holding the sensor approximately 3 m in the air. The positive and negative data presented in this report are the κ value of the survey area compared to the κ value of the air, being, theoretically, zero.

Data were collected and stored automatically in the TSC1 data logger by using a push button trigger on the MS2. The geophysicists walked at a constant pace along each traverse, pausing only briefly at each survey station to obtain a measurement of magnetic susceptibility. The data were downloaded to a field computer using Trimble Pathfinder Office 2.9 software.

Data Processing

Preliminary Data Treatment The data were exported from Pathfinder Office 2.9 to Microsoft Excel. The Excel data

were gridded in xyz format as northing, easting and κ, using Golden Software Surfer 8.00.

Further Processing A natural neighbour interpolation function was applied to the data to provide a

smooth, aesthetically pleasing image for presentation. No further processing functions were applied due to the high quality of the data collection.

Graphical Display Contour plots can be shaded to emphasise particular regions between lines. Processed

data are shown in interpolated colourscale contour plot format in Figures 5, 13, 18 and 23.


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The colourscale plot presents data as pixels on a linear colour shaded scale, increasing or decreasing dependent on the values of the maximum and minimum clip. The geophysical data have not been clipped. The main advantage of this display option is that the data can be viewed as a base map. A disadvantage is that the interpolation process can exaggerate isolated high or low data (this is noticeable over areas where no data has been collected, e.g. in the space occupied by a field boundary); to compensate for this, each survey sta-tion has been marked by a small black dot, creating a point cloud, to an accuracy of ±1 m, so that exaggeration between points can be visualised. An interpretation plot of the magnetic susceptibility data is presented in Figures 6, 14, 19 and 24.

Reporting, Mapping & Archiving The geophysical survey and report follow the recommendations outlined in the English Heritage Guidelines (David et al. 2008) and IFA Paper No. 6 (Gaffney et al. 2002) as a minimum standard. The conditions of the Detection Licence issued by the Licensing Section of the Department of the Environment, Heritage and Local Government require a copy of this report.

Geophysical data, figures and text are archived following the recommendations of the Archaeology Data Service (Schmidt 2001).

Field boundaries were mapped and drawn based upon data gathered by the DGPS. Technical information on the equipment used, data processing and methodology are given in Appendix 1. Appendix 2 details the survey geo-referencing information and Ap-pendix 3 describes the composition and location of the archive.

Results & Discussion The interpretation figures should not be looked at in isolation but in conjunction with the relevant discussion section and with the information contained in the Appendices. Features are numbered in the relevant figures listed below [G1=gradiometer anomalies, M1=magnetic susceptibility anomalies] and are described and interpreted within the text.

In magnetic gradiometer data, a dipolar anomaly or ‘iron spike’ is a response to buried ferrous objects, often in the topsoil. Iron spikes generally are not removed in geophysical data, although often modern in origin, they can be indicative of archaeological material.

Magnetic Gradiometer Survey Figure 10 – Pre-processed Magnetic Gradiometer Data Figure 11 – Magnetic Gradiom-eter Data Figure 12 – Magnetic Gradiometer Interpretation Anomaly [G19] represents an arcing boundary ditch which appears to be made up of two parallel ditches on the western side, whereas only a single ditch was detected to the east. Measuring 116 m in length this anomaly is forms an enclosure ditch associated with the medieval boundary and possible structure revealed during the excavation. Some weakly magnetic parallel linear features can be seen, enclosed by the G19 ditch – these are likely to represent plough furrows.

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Anomaly [G20] is a linear ditch which runs from the edge of the survey area for a length of 56 m and terminates against anomaly G19. This relict field boundary can be seen in the 1

st

Edition Ordnance Survey Map of the area. Anomaly [G21] comprises several linear parallel ditches which run from the exca-

vation area in the north to the south and extend beyond the survey area. Measuring approximately 50 m in length, these anomalies represent a continuation of the parallel ditches revealed during the excavation.

Anomaly [G22] is a linear ditch which runs from the excavation area for a length of 30 m and terminates against G19. Anomaly [G23] is a curvilinear ditch which extends from G19, aligned SE-NW, extending beyond the survey area. Measuring 40 m in length, this anomaly could be archaeological or agricultural in origin.

Magnetic Susceptibility Survey Figure 13 – Magnetic Susceptibility Data Figure 14 – Magnetic Susceptibility Interpre-tation The magnetic susceptibility data is reasonably enhanced at this site, with general trends between 2 to 14 SI Units, with lower magnetic susceptibility in the SW corner and higher background responses.

Anomaly [M5] marks the location of a boundary between low magnetic susceptibility values to the southwest and slightly higher values to the north. This anomaly probably marks the boundary to the archaeological activity.

Anomaly [M6] is located inside the higher values of M5 and marks a further in-crease in the values, probably associated with archaeological remains. The location of this anomaly places it inside G19 the enclosure ditch detected in the magnetic gradiometer data, suggesting that this enclosure ditch did represent the extent of the majority of ar-chaeological activity.

Conclusion

Achievement of Objectives The geophysical surveys have assessed land adjacent to archaeologically significant sites which were identified within the C.P.O boundary of the new road. The magnetic gradi-ometer surveys have identified and mapped possible archaeological remains within these areas which will help to enhance the interpretation of the sites’ extent and composition. The magnetic susceptibility survey across the sites was useful in that it reinforced certain trends identified in the magnetic gradiometer data.

Summary of ResultsA number of possible ditches were detected which have a direct relationship to the ar-chaeological excavation results. The edge of the probable zone of archaeological activity was also established with the detection of an arcing enclosure ditch. A number of single


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and interconnecting ditches were also detected which may be archaeological or agricul-tural in origin.

Dissemination The results of this survey were submitted to Eachtra Archaeological Projects. Earthsound will ensure that copies will be forwarded to the Department of the Environment, Herit-age and Local Government and the National Museum of Ireland in compliance with the Licence agreement.

AcknowledgementsFieldwork: James Bonsall BA (Hons) MSc PIFA Daniel Jones MA Heather Gimson BA (Hons) MSc MIAI Report: Heather Gimson James Bonsall Graphics: Heather Gimson

Bibliography Clark, A.J. 1996 Seeing Beneath the Soil, London, Batsford

David, A. Linford, N. & Linford, P. 2008 Geophysical Survey in Archaeological Field Evaluation, Second Edition, English Heritage

Eachtra 2008a Busherstown Preliminary Archaeological Report, N7 Castletown to Nenagh (Derrinsallagh to Ballintotty) Road Scheme, Unpublished Archaeological Report by Eachtra Archaeological Projects

Eachtra 2008b Drumbaun 2 Preliminary Archaeological Report, N7 Castletown to Nenagh (Derrinsallagh to Ballintotty) Road Scheme, Unpublished Archaeological Report by Eachtra Archaeological Projects

Eachtra 2008c Drumroe 1 Preliminary Archaeological Report, N7 Castletown to Nenagh (Derrinsallagh to Ballintotty) Road Scheme, Unpublished Archaeological Report by Eachtra Archaeological Projects

Eachtra 2008d Killeisk 1 Preliminary Archaeological Report, N7 Castletown to Nenagh (Derrinsallagh to Ballintotty) Road Scheme, Unpublished Archaeological Report by Eachtra Archaeological Projects

Eachtra 2008e Park 1 Preliminary Archaeological Report, N7 Castletown to Nenagh (Derrinsallagh to Ballintotty) Road Scheme, Unpublished Archaeological Report by Eachtra Archaeological Projects

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Gaffney, C., Gater, J. & Ovenden, S. 2002 The use of Geophysical Techniques in Archaeological Evaluations, IFA Paper No. 6, Institute of Field Archaeologists

Schmidt, A. 2001 Geophysical Data in Archaeology: A Guide to Good Practice, Archaeology Data Service, Oxford, Oxbow

Scollar, I., Tabbagh, A., Hesse, A. And Herzog, I. 1990 Archaeological Prospecting and Remote Sensing, Cambridge, Cambridge University Press. Topics in Remote Sensing Vol. 2

The following texts are referenced in the Technical Appendix:

Walker, R. 2000 Geoplot Version 3.00 for Windows, Instruction Manual, Version 1.2, Clayton, West Yorkshire

Education

Archaeological Report - Drumroe, Co. Offaly (Ireland)