Wentloog, Cardiff: Archaeological Watching Brief

Newlands Road, Wentloog, Cardiff: archaeological watching brief

Front cover: Trench 1 south west facing section GGAT

Contents PageSummary ........................................................................................................................2 Acknowledgements .........................................................................................................2 Copyright notice.............................................................................................................2 1. Introduction..........................................................................................................3 1.1 Project background and commission .................................................................3 1.2 Location and Topography ..................................................................................3 1.3 Historical and archaeological background.........................................................5 2. Methodology .........................................................................................................7 3. Finds ....................................................................................................................13 4. Conclusion ..........................................................................................................14 Appendix I: Context Inventory.................................................................................16 Figures Figure 1. Site location ....................................................................................................4 Figure 2. Plan showing the trench location....................................................................8 Plates Plate 1. Trench 1 south west facing section .................................................................10 Plate 2. Trench 5 north east facing section ..................................................................13


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Summary

Golder Associates (UK) Ltd commissioned the Glamorgan-Gwent Archaeological Trust Projects Division (GGAT Projects) to undertake an archaeological watching brief during geotechnical site investigations at Newlands Road, Wentloog, Cardiff.

No archaeological finds, or features were encountered during the watching brief. The known stratigraphy of the Wentloog Formation was identified down to the alluvial clays of the Middle Wentloog including the well-developed phragmites-rich peat horizon.

Acknowledgements

This project was managed by Richard Lewis BA MIfA and the fieldwork undertaken by Rowena Hart BSc MA. The photographs and report were prepared by Rowena Hart BSc MA, with illustrations by Paul Jones (GGAT Senior Illustrator).

Copyright notice

The copyright of this report is held by Glamorgan-Gwent Archaeological Trust Ltd; GGAT has granted an exclusive licence to Golder Associates (UK) Ltd. and their agents to use and reproduce the material it contains. Ordnance Survey maps are reproduced under licence (AL 10005976), annotations are GGAT copyright.


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1. Introduction

1.1 Project background and commission

Golder Associates outlined a series of geotechnical site investigations on a plot of land off Newlands Road, Wentloog, Cardiff. The Curatorial Division of the Glamorgan-Gwent Archaeological Trust (acting as the Council’s archaeological advisors) recommended an archaeological watching brief to be conducted on all ground works associated with the site investigations, in order to inform the decision as to whether a full evaluation would be required as part of the Environmental Impact Assessment (EIA).

The Glamorgan-Gwent Archaeological Trust Projects Division (GGAT Projects) was commissioned by Golder Associates to undertake the watching brief. This was undertaken on the 10th and 11th December 2008.

1.2 Location and Topography

Newlands Road is situated on the Wentloog Levels, on the north shore of the Severn Estuary (Figure 1). The extensive estuarine low-lying alluvial plain of the Wentloog Level forms the western portion of the Gwent Levels between the River Rumney, east of Cardiff and the River Usk at Newport. The Wentloog Level is spread over three parishes, Rumney, Peterstone Wentloog and St. Brides Wentloog. The Levels were formed through gradual sediment deposition on the banks of the Severn during the post-glacial rise in sea level and the surface deposits are of Quaternary estuarine clays and silts interbedded with layers of peat and with poorly drained and neutral soils. These surface deposits rest on soft Mesozoic (Triassic) marls except at the southwest end where Triassic conglomerates overlap a low ridge of resistant Silurian sandstones (Rumney Grit) (Rippon 1996). The Levels are identified as a Site of Special Scientific Interest (SSSI) chiefly for their diversity of flora and fauna associated with the reens and banks; the foreshore areas are also noted for hosting migrant bird populations. Principal features of the landscape include natural watercourses, natural palaeochannels, artificial reens and an active salt marsh.


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1.3 Historical and archaeological background

The Gwent Levels have been designated an Outstanding Historic Landscape (HLW(Gt)2), as they represent the largest and most significant example in Wales of a “hand-crafted” landscape. The Levels are entirely the work of humans, having been recurrently inundated and reclaimed from the sea from the Roman period onwards. The area has distinctive patterns of settlement, enclosure and drainage systems belonging to successive periods of use, and a proven and possibly vast potential for extensive, well-preserved, buried, waterlogged, archaeological and palaeoenvironmental deposits surviving from earlier landscapes (CADW and ICOMOS 1998, 61-5). The Levels rich and varied range of archaeological features and artefacts include prehistoric footprints, occupation sites and artefacts, Roman and medieval field systems, a medieval sea wall and modern WW2 defence structures. The greatest influence upon the Levels landscape probably since Roman times is land reclamation works of artificial drainage channels (Lewis 2005b).

The prehistoric period is represented by cattle hoofprints, Bronze Age roundhouses and post-settings, flint, bone and discreet pottery scatters, mainly situated on the intertidal foreshore to the southeast of the business park (Allen 1996b; Bell et al 2000). More recent work has identified several prehistoric timber structures thought to be the remains of fish traps or temporary shelters within the intertidal zone, also to the southeast of the business park (Lewis 2005a, 9-11; Tuck 2004, 10-11). Later prehistoric activity is attested to by a Bronze Age looped and socketed axe (PRN 01999s) found in the vicinity of Lagoon B and buildings dating from Iron Age have been excavated some distance to the east of the development area at Goldcliff and at Greenmoor Arch.

Just over a kilometre to the northwest of the development area is the line of the Caerleon-Cardiff Roman road. Air photograph evidence indicates that a rectilinear network of relict ditches and grips extends across the area, linked to a system of curvilinear reens. The regular ditch system is thought to have originated in a reclamation of the marshland undertaken in either the Roman or medieval periods (Allen and Fulford 1986; Locock 1998). Marvell (Nayling and Mcgrail 2004) argues that on the levels the Roman landscape is buried and that the present landscape is of medieval or post-medieval origin. To the south of the development area is the remains of a late 16th-century sea wall (Scheduled Ancient Monument Gm 474) constructed when pressure from rising tides and/or frequent floods made it necessary for new sea defences to be provided. This monument is of great importance as it is one of the few features that can be accurately dated and whatever the argument, the rectangular field pattern to the north of it is accepted to have predated construction of the sea wall and is thus considered a significant early landscape.

Further evidence for the widespread reclamation of this landscape was found during a watching brief carried out in 1997 (Sell 1997) when in situ wooden structures were discovered in three locations (PRNs 02827s, 02828s and 02829s,). These structures are considered to be part of a water management feature of unknown length, with a number of flanged pieces being interpreted as forming part of a sluice gate. While no conclusive dating has been established for this feature, it is likely to date from the medieval period or later.

Generally, the medieval landscape was dominated by pasture, much of it common; there were also extensive ecclesiastical estates within the Levels area. Scattered


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settlement has continued across the Wentloog Levels, the mid 17th century farmhouse of Long Cross just to the northeast of the development area is one such example. The post-medieval period saw the gradual enclosure of common land, a process completed only in the 19th century.


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2. Methodology Five test trenches were mechanically excavated for the purpose of geotechnical investigations (Figure 2). The trenches were excavated mechanically using a 2.5m wide grading bucket. It was required that the depth of the trenches measured a minimum of 4.60m. The trenches were located in the four corners of the proposed building footprint and one trench in the centre (Figure 3).

A full written, drawn and photographic record was made of all archaeological contexts, in accordance with the GGAT Manual of Excavation Recording Techniques. Contexts were recorded using a single continuous numbering system, and are summarised in Appendix 1. All contexts were photographed. Finds were selected according to the GGAT Manual of Excavation Recording Techniques discard policy; no finds were retained as they were all identified on-site as modern.

An archive of records relating to the preparation of the reports has been prepared to the specifications in Management of Archaeological Projects (English Heritage, 1991) Appendix 6 and UKIC’s Archaeological Archives: a guide to best practice in creation, compilation, transfer and curation 2007.

After an appropriate period has elapsed, copies of the report and archive index will be deposited with the regional Historic Environment Record (HER). A copy of the report and archive index will also be deposited with the National Monuments Record, RCAHMW, Aberystwyth.


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3. Results

Trench 1 (Northern corner - ST23627, 79532) This trench measured 3.5m in length and 2.5m in width. The maximum depth of excavation was 5.0m (Plate 1).

The basal deposit encountered in this trench was a blue grey alluvial clay (107). There were no inclusions in this deposit other than occasional anaerobically preserved roots. The deposit had an average depth of 1.75m although it was not excavated to its base. Sealing this was a well developed peat horizon (106), rich in Phragmites australis (common reed). This peat had a depth of 0.25m and its upper surface was encountered at exactly 3.0m below current ground level. Overlying the peat was a deposit of blue grey alluvial clay (105) with an average depth of 1.33m and void of any inclusions. Sealing this alluvial clay was a mottled alluvial grey clay with reddish brown inclusions of marl clay (104). This deposit had an average depth of 0.60m. Overlying 104 was a poorly developed peat horizon (103). This deposit comprised grasses, moss, leaves and large branches. Some machine cut posts were also included. This deposit had an average depth of 0.1m with the upper surface of the peat encountered at a depth of 0.97m below current ground level. Sealing this organic deposit was a mixed deposit (102) comprising a grey silty clay with inclusions of reddish brown marl clay. This deposit was very loose and clearly redeposited. This deposit contained modern building and industrial debris including modern bricks, stone, iron objects (hinges, nails, rods). The average depth of this deposit was 0.87m. The uppermost deposit in this trench (101) was a thin, mid brown, silty clay topsoil with an average depth of 0.1m

101

102

103

104

105

106

107

Plate 1. Trench 1 south west facing section


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Trench 2 (Northern corner - ST23547, 79468) This trench measured 3.5m in length and 2.5m in width. The maximum depth of excavation was 4.7m.

The basal deposit encountered in this trench was a blue grey alluvial clay (208). There were no inclusions in this deposit other than occasional anaerobically preserved roots. The deposit had an average depth of 1.4m although the deposit was not excavated to its base. Sealing this was a well developed peat horizon (207), rich in Phragmites australis (common reed). This peat had a depth of 0.3m and its upper surface was encountered at exactly 3.0m below current ground level. Overlying the peat was a deposit of blue grey alluvial clay (206) with an average depth of 1.4m and void of any inclusions. Sealing this alluvial clay was a mottled alluvial grey clay with reddish brown inclusions of marl clay (205). This deposit had an average depth of 0.7m. Overlying 205 was a poorly developed peat horizon (204). This deposit comprised grasses, moss, leaves and large branches. This deposit had an average depth of 0.1m with the upper surface of the peat encountered at a depth of 0.8m below current ground level. Sealing this organic deposit was a mixed deposit (203) comprising a grey silty clay with inclusions of reddish brown marl clay. This deposit was very loose and clearly redeposited. The average depth of this deposit was 0.4m. Overlying this redeposited clay and marl clay was a grey silty clay with modern inclusions of brick, stone rubble and modern iron fittings (202). The uppermost deposit in this trench (201) was a thin, mid brown, silty clay topsoil with an average depth of 0.1m.

Trench 3 (Southwest corner - ST23640, 79458) This trench measured 3.9m in length and 2.5m in width. The maximum depth of excavation was 4.69m.

The basal deposit encountered in this trench was a blue grey alluvial clay (307). There were no inclusions in this deposit other than occasional anaerobically preserved roots. The deposit had an average depth of 1.39m although the deposit was not excavated to its base. Sealing this was a well developed peat horizon (306), rich in Phragmites australis (common reed). This peat had a depth of 0.3m and its upper surface was encountered at exactly 3.0m below current ground level. Overlying the peat was a deposit of blue grey alluvial clay (305) with an average depth of 1.7m and void of any inclusions. Sealing this alluvial clay was a mottled alluvial grey clay with reddish brown inclusions of marl clay (304). This deposit had an average depth of 0.7m. Overlying 304 was a very compact iron slag rich deposit with iron fragments and pieces of cotton and nylon fabrics (303). The slag was fragmented into small pieces (5mm – 30mm). This deposit had an average depth of 0.16m. Overlying 303 was a grey silty clay with modern inclusions of brick, stone rubble and modern iron fittings (302) with an average depth of 0.9m. The uppermost deposit in this trench (301) was a thin, mid brown, silty clay topsoil with an average depth of 0.1m.


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Trench 4 (Eastern corner - ST23664, 79479) This trench measured 3.9m in length and 2.5m in width. The maximum depth of excavation was 5.0m.

The basal deposit encountered in this trench was a blue grey alluvial clay (407). There were no inclusions in this deposit other than occasional anaerobically preserved roots. The deposit had an average depth of 1.8m although the deposit was not excavated to its base. Sealing this was a well developed peat horizon (406), rich in Phragmites australis (common reed). This peat had a depth of 0.2m and its upper surface was encountered at exactly 3.0m below current ground level. Overlying the peat was a deposit of blue grey alluvial clay (405) with an average depth of 1.65m and void of any inclusions. Sealing this alluvial clay was a mottled alluvial grey clay with reddish brown inclusions of marl clay (404). This deposit had an average depth of 0.3m. Overlying 404 was a very compact iron slag rich deposit with iron fragments and pieces of cotton and nylon fabrics (403). The slag was fragmented into small pieces (5mm – 30mm). This deposit had an average depth of 0.1m. Overlying 403 was a grey silty clay with modern inclusions of brick, stone rubble and modern iron fittings (402) with an average depth of 0.85m. The uppermost deposit in this trench (401) was a thin, mid brown, silty clay topsoil with an average depth of 0.1m.

Trench 5 (Eastern corner - ST23614, 79489) This trench measured 4.4m in length and 2.5m in width. The maximum depth of excavation was 4.75m (Plate 2).

The basal deposit encountered in this trench was a blue grey alluvial clay (507). There were no inclusions in this deposit other than occasional anaerobically preserved roots. The deposit had an average depth of 1.6m although the deposit was not excavated to its base. Sealing this was a well developed peat horizon (506), rich in Phragmites australis reeds. This peat had a depth of 0.15m and its upper surface was encountered at exactly 3.0m below current ground level. Overlying the peat was a deposit of blue grey alluvial clay (505) with an average depth of 1.25m and void of any inclusions. Overlying 505 was a poorly developed peat horizon (504). This deposit comprised grasses, moss, leaves and large branches. Included within the organic material was a large base of modern glass bottle and a modern plastic switch. This deposit had an average depth of 0.15m. Overlying 504 was a mixed deposit (503) comprising a grey silty clay with inclusions of reddish brown marl clay. This deposit was very loose and clearly redeposited. The average depth of this deposit was 1.16m. Deposit 503 was overlain by a greyish brown silty clay (502) with modern inclusions of brick, stone rubble and modern iron objects with an average depth of 0.32m. The uppermost deposit in this trench (501) was a thin, mid brown, silty clay topsoil with an average depth of 0.12m.


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501

502

503

504

505

506

507

Plate 2. Trench 5 north east facing section

4. Finds All finds recovered from the excavation were of modern date. They were examined on site and discarded.


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5. Conclusion The watching brief revealed similar stratigraphies in each of the five geotechnical trenches. The basal deposit encountered in all trenches was an alluvial clay of the Middle Wentloog Formation. A well developed peat deposit formed the upper surface of this Middle Wentloog Formation and has been dated at an adjacent site on the Wentloog Levels to the Bronze Age period (Locock 1998). The Upper Wentloog Formation overlaid the peat and was itself overlain by a medieval or post-medieval deposit. The interface between the Upper Wentloog Formation and the medieval or post-medieval deposit represents the exposed Roman landsurface of this area, referred to as the Wentloog Palaeosol by Allen and Fulford (Fulford et al 1994, 177). This stratigraphy supports the description that the current medieval/post-medieval Wentloog Level is not a relict Roman landscape (Marvell 2004, 94-95).

The deposits overlying the Wentloog Formations are all modern in date and are associated with the building, occupation and disuse of the timber yard that occupied the southern part of the development area for no more than 21 years during the mid 20th century. From the Ordnance Survey 1:25,000 map of 1968 the timber yard is clearly visible covering almost half of the development area with railway sidings. By the Ordnance Survey 1:10,000 of 1989 there is no sign of the timber yard.

No archaeological features or finds were encountered during this watching brief. The stratigraphy revealed the uppermost meter across the site comprised modern and redeposited material. The medieval/post-medieval horizon was encountered at an average of 1m below current ground level. The Roman horizon was encountered at an average of 1.6m below current ground level (although it was deeper in Trench 3 at 2.3m below ground level). The Bronze Age peat horizon of the Middle Wentloog Formation was encountered at an average of 3.0m below ground level. The alluvial clay of the Middle Wentloog Formation, underneath the peat was not excavated to its full depth.


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Bibliography

Allen, JRL 1996a, The seabank on the Wentloog Level, Gwent: date of set-back from documentary and pottery evidence. Archaeology in the Severn Estuary 7, 67-84.

Allen, JRL, 1996b, Three final Bronze Age occupations at Rumney Great Wharf on the Wentloog Level, Gwent. Studia Celtica, The Bulletin of the Board of Celtic Studies 30 (1996), 1-16

Allen, JRL and Fulford, MG, 1986, The Wentloog Level: a Romano-British saltmarsh reclamation in south-east Wales. Britannia 17, 91-118.

Bell, M, Caseldine, A and Neumann, H, 2000, Prehistoric Intertidal Archaeology in the Severn Estuary Council for British Archaeology Research Report 120, York

Cadw and ICOMOS, 1998, Register of Landscapes: Landscapes of Outstanding Historic Interest, Pt 2.1. Cardiff.

Lawler, M, 1995, Cardiff Food Park, roundabout, archaeological watching brief. GGAT unpublished report no 95/017, Swansea.

Lewis, RL, 2005a, Rumney Great Wharf II, Cardiff, archaeological watching brief interim report. GGAT unpublished report 2005/040

Lewis, RL, 2005b, Capital Business Park: archaeological watching brief. GGAT unpublished report 2005/068

Locock, M, 1998, GGAT 50 Coastal archaeology survey River Rhymney, Cardiff (South Glamorgan) to river Wye, Monmouthshire (Gwent), GGAT unpublished report 98/010

Locock, M, 1998, Land north of Wentloog Avenue, Cardiff Electronics facility Phase 1. Archaeological mitigation: Stage 4. Radiocarbon dating of palaeoenvironmental sample. GGAT Unpublished Report 98/041

Nayling, N and McGrail, S, 2004, The Barland's Farm Romano-Celtic Boat Council for British Archaeology Research Report 138, York.

Marvell, AG, 2004, Roman settlement and economy. In Nayling and McGrail 2004, 91 - 110

Rippon, S, 1996, Gwent Levels: Evolution of a wetland landscape, Council for British Archaeology Research Report 105, York.

Sell, S, 1997, Archaeological watching brief at Cardiff Food Park, Rumney. GGAT unpublished report no: 97/056, Swansea

Tuck, M, 2004, Flood Defence Works at Rumney Great Wharf, Cardiff: archaeological watching brief. GGAT unpublished report 2004/102


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Appendix I: Context Inventory Context Location Type Depth

m (bgl) Description Period

101 Trench 1 Deposit 0 – 0.1 Mid brown, silty clay topsoil

Modern

102 Trench 1 Deposit 0.1 – 0.97 A redeposited, mixed silty clay with inclusions of red marl clay. Frequent inclusions of industrial debis including machine made bricks, large stone fragments, plastics and concrete.

Modern

103 Trench 1 Deposit 0.97 – 1.07 A black peaty deposit. Including fragments of wood/branches, roots/leaves and grass. Ground surface belonging to the Timber Yard (c.1968)

Modern

104 Trench 1 Deposit 1.07 – 1.67 A brown-grey alluvial clay mottled with inclusions of brown marl clay.

Medieval/ Post-medieval

105 Trench 1 Deposit 1.67 – 3.0 A blue-grey alluvial clay of the Upper Wenloog Formation.

Roman

106 Trench 1 Deposit 3.0 – 3.25 A phragmites australis rich peat sealing the top of the Middle Wentloog Formation.

Bronze Age

107 Trench 1 Deposit 3.25 – 5.0 n.b.

A blue-grey alluvial clay of the Middle Wentloog Formation.

Bronze Age

201 Trench 2 Deposit 0 – 0.1 A mid brown silty clay topsoil.

Modern

202 Trench 2 Deposit 0.1 – 0.4 A grey clay containing frequent industrial debris including brick, stone numerous iron objects and fittings.

Modern

203 Trench 2 Deposit 0.4 – 0.8 A redeposited, mixed silty clay with inclusions of red marl clay.

Modern

204 Trench 2 Deposit 0.8 – 0.9 A black peaty deposit. Including fragments of wood/branches, roots/leaves and grass. Ground surface belonging to the Timber Yard (c.1968)

Modern



206 Trench 2 Deposit 1.6 – 3.0 A blue-grey alluvial clay of the Upper Wenloog Formation.

Roman


Bronze Age


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Context Location Type Depth

m (bgl) Description Period

208 Trench 2 Deposit 3.3 – 4.7 n.b. A blue-grey alluvial clay of the Middle Wentloog Formation.

Bronze Age

301 Trench 3 Deposit 0 – 0.1 A mid brown silty clay topsoil

Modern

302 Trench 3 Deposit 0.1 – 1.0 A grey clay deposit comprising industrial waste (bricks, concrete, kerb stones, plastic bags)

Modern

303 Trench 3 Deposit 1.0 – 1.16 A slag rich deposit containing iron objects (nails/hinges/road irons) and fragments of cloth. Ground surface belonging to the Timber Yard (c.1968)

Modern



305 Trench 3 Deposit 2.3 – 3.0 A blue grey alluvial clay of the Upper Wenloog Formation.

Roman


Bronze Age


A blue-grey alluvial clay of the Middle Wentloog formation.

Bronze Age


Modern

402 Trench 4 Deposit 0.1 – 0.95 A brown grey silty clay comprising modern building material (brick, iron, concrete and plastics).

Modern

403 Trench 4 Deposit 0.95 – 1.05 A thin iron and slag rich compact industrial deposit. Ground surface belonging to the Timber Yard (c.1968)

Modern




Roman


Bronze Age

407 Trench 4 Deposit 3.2 – 5.0 n.b. A blue grey alluvial clay of the Middle Wentloog formation.

Bronze Age


Modern

502 Trench 5 Deposit 0.12 – 0.44 A grey brown silty clay containing iron objects, stone and modern brick.

Modern


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Context Location Type Depth m (bgl)

Description Period

503 Trench 5 Deposit 0.44 – 1.6 A loosely bound, redeposited mixed grey clay and brown clay.

Modern

504 Trench 5 Deposit 1.6 – 1.75 A black peaty deposit. Including fragments of wood/branches, roots/leaves and grass. Ground surface belonging to the Timber Yard (c.1968). Contained modern glass and plastic

Modern


Roman

506 Trench 5 Deposit 3.0 – 3.15 A peat horizon forming the upper layer of the Middle Wentloog Formation. There were fewer phragmites reeds visible in this trench.

Bronze Age


A blue grey alluvial clay of the Middle Wentloog Formation.

Bronze Age

n.b. – not bottomed

Documents

Wentloog, Cardiff: Archaeological Watching Brief