Pont Blaen Cwm Du, Libanus, Powys Archaeological Record & Watching Brief Report Ross Cook
NGR: SN 94237 21489
Project No.: AD092
Client Project No.: H3075
Date: November 2020
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Prepared for: Powys County Council Highways, Powys County Hall, Spa Road East, Llandrindod Wells, LD1 5LG Clients Project No: H3075
By: ArchaeoDomus Archaeological & Heritage Services 3 Cysgod-y-Coed, Cwmann, Lampeter, Carmarthenshire, SA48 8DN Tel:
+44 (0) 1570 218048
+44 (0) 7910 213557
Email: ross.cook@archaeodomus.co.uk www.archaeodomus.co.uk
Version
Date
v1.0
12.11.2020
© ArchaeoDomus 2020. All Rights Reserved
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
CONTENTS List of Figures ......................................................................................................................................... iv List of Plates ........................................................................................................................................... iv Acknowledgements .................................................................................................................................. v Abbreviations used in this report ............................................................................................................. v Project Team........................................................................................................................................... vi Summary ................................................................................................................................................. 1 Crynodeb................................................................................................................................................. 2 1 INTRODUCTION .................................................................................................................. 2 1.1 General....................................................................................................................................... 3 2 SITE AND LOCATION .......................................................................................................... 5 2.1 General....................................................................................................................................... 5 2.2 Geology....................................................................................................................................... 6 3 HISTORICAL BACKGROUND ............................................................................................. 7 3.1 Introduction................................................................................................................................ 7 3.2 Historical Background ................................................................................................................. 7 3.3 Roman ....................................................................................................................................... 7 3.4 Post-Medieval ............................................................................................................................. 7 4 AIMS AND OBJECTIVES..................................................................................................... 10 4.1 Watching Brief .......................................................................................................................... 10 4.2 Results ...................................................................................................................................... 10 5 METHODOLOGY ................................................................................................................ 11 5.1 Introduction.............................................................................................................................. 11 5.2 Survey Record............................................................................................................................ 11 5.3 Photographic Recording.............................................................................................................. 11 5.4 Reinstatement ........................................................................................................................... 12 5.5 Documentary Research ............................................................................................................... 12 5.6 Reporting .................................................................................................................................. 12 5.7 Health and Safety...................................................................................................................... 12 6 PHOTOGRAMMETRY METHODOLOGY AND OUTPUT ............................................ 13 6.1 Introduction.............................................................................................................................. 13 6.2 Method ..................................................................................................................................... 13 6.3 Results ...................................................................................................................................... 14 7 ARCHAEOLOGICAL RECORD .......................................................................................... 15 7.1 Introduction.............................................................................................................................. 15 7.2 Description ............................................................................................................................... 15 7.3 Development ............................................................................................................................. 16 7.4 Damage .................................................................................................................................... 16 8 WATCHING BRIEF RESULTS ............................................................................................. 17 8.1 Introduction.............................................................................................................................. 17 8.2 Archaeological Result ................................................................................................................. 17 8.3 Site Meeting – 13th August 2020 ............................................................................................... 17
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
8.4 Excavation of Southern Spandrel – 26th August 2020 .................................................................. 18 8.5 River Grading – 2nd September 2020 .......................................................................................... 19 8.6 Finds Assemblage....................................................................................................................... 19 8.7 Environmental .......................................................................................................................... 19 9 DISCUSSION ........................................................................................................................ 20 10 ARCHIVING.......................................................................................................................... 21 11 SOURCES .............................................................................................................................. 21 APPENDIX I ........................................................................................................................................ 23 APPENDIX II ......................................................................................................................................... 1 APPENDIX III...................................................................................................................................... 40
List of Figures Fig. 1 – Pre-works photogrammetric elevations and vault of Pont Blaen Cwm Du. ........................................ 3 Fig. 2 – Location – Pont Blaen Cwm Du. ................................................................................................... 5 Fig. 3 – Location – Pont Blaen Cwm Du. ................................................................................................... 5 Fig. 4 – The Cambrian, 26th July 1823. ..................................................................................................... 8 Fig. 5 – Map of the Turnpike Trusts in South Wales, 1843. .......................................................................... 9 Fig. 6 – 1887 25-inch to One Mile, OS. .................................................................................................. 38 Fig. 7 – 1904 25-inch to One Mile, OS. .................................................................................................. 38 Fig. 8 – Orthomosaic – Pont Blaen Cwm Du. ........................................................................................... 38 Fig. 9 – Excavation areas – Pont Blaen Cwm Du. ..................................................................................... 39 Fig. 10 – Assets – Pont Blaen Cwm Du..................................................................................................... 40 Fig. 11 – Height Map – Pont Blaen Cwm Du........................................................................................... 41 Fig. 12 – Height Map Assets – Pont Blaen Cwm Du.................................................................................. 42 Fig. 13 – Elevations – Pont Blaen Cwm Du. ............................................................................................. 43
List of Plates Plate 1 – Pre-works – West elevation of bridge. .......................................................................................... 41 Plate 2 – Pre-works – East elevation of bridge........................................................................................... 41 Plate 3 – Pre-works – Collapse of roadway, viewed towards south. ............................................................... 42 Plate 4 – Pre-works – Collapse of roadway – view towards south................................................................. 42 Plate 5 – East elevation, showing walls of sheep wash. ................................................................................ 43 Plate 6 - North sheep wash wall, showing groove for sluice gate. ................................................................. 43 Plate 7 - - South sheep wash wall, showing groove for sluice gate. ................................................................ 44 Plate 8 – Arch vault, showing south abutment, vaulting and collapse. ......................................................... 44 Plate 9 – Arch vault, showing collapse. ...................................................................................................... 45 Plate 10 – Pre-works – Fill of spandrel to bank, north bank. Photo turned 90° anticlockwise. ...................... 45 Plate 11 – Pre-works – Possible paver found in stream to east of bridge........................................................ 46 Plate 12 – Pre-works – Possible paver found in stream to east of bridge........................................................ 46 Plate 13 – Pre-works – Possible paver found in stream to east of bridge........................................................ 47 Plate 14 – Watching Brief – Spandrel fill to north bank, after partial excavation. ........................................ 47 Plate 15 – Watching Brief – Internal face of north-west spandrel and arch................................................... 48 iv
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 16 – Watching Brief – Internal face of north-east spandrel and arch, with sheep wash wall behind. ...... 48 Plate 17 – Watching Brief – Surviving portion of north-west arch and abutment. ........................................ 49 Plate 18 – Watching Brief – 20th century concrete plinth to east end of north abutment. ............................... 49 Plate 19 – Watching Brief – Threshold between sheep wash (east) and underside of bridge (west). ................. 50 Plate 20 – Watching Brief – South wall of sheep wash, after removal. .......................................................... 50 Plate 21 – Watching Brief – Area of grading and track damage to north-east wall of Tollgate House. ............. 51 Plate 22 – Watching Brief – Works undertaken without archaeological monitoring....................................... 51 Plate 23 – Watching Brief – South abutment, showing stonework plinth and roughly dressed blocks. ............. 52 Plate 24 – Watching Brief – South abutment after riverbed clearing. .......................................................... 52 Plate 25 – Watching Brief – Roadway, showing voussoirs and fill. ............................................................... 53 Plate 26 – Watching Brief – Concrete filled hessian sack, part of sheep wash construction. ............................. 53 Plate 27 – Watching Brief – Boundary wall, cut through without archaeological monitoring. ....................... 54 Plate 28 – Watching Brief – Spandrel excavation, showing vault and internal face of west spandrel. .............. 54 Plate 29 – Watching Brief – Spandrel excavation, showing vault and internal face of east spandrel................ 55 Plate 30 – Watching Brief – View north, showing arch and iron reinforcement for concrete pour. .................. 55 Plate 31 – Watching Brief – Completed rebuild of north abutment and arch, viewed west. ........................... 56 Plate 32 – Watching Brief – Completed rebuild of north abutment and arch, viewed west. ........................... 56 Plate 33 – Watching Brief – Completed rebuild of north abutment and arch, viewed north. ......................... 57 Plate 34 – Watching Brief – Completed rebuild of north abutment and arch, viewed east. ............................ 57 Plate 35 – Watching Brief – West elevation on completion of reinstatement. ................................................. 58 Plate 36 – Watching Brief – East elevation on completion of reinstatement. ................................................. 58 Plate 37 – Watching Brief – End of works clean and grading of north bank. ................................................ 59 Plate 38 – Watching Brief – View west downstream, showing clean and grading of banks. ............................ 59 Plate 39 – Watching Brief – View of south bank, showing clean and grading of bank. .................................. 60 Plate 40 – Watching Brief – View south, showing new surfacing to roadway. ............................................... 60 Plate 41 – Possible Roman paver (FN01). ................................................................................................. 61 Plate 42 – Possible Roman paver (FN02). ................................................................................................. 61 Plate 43 – Possible Roman paver (FN03). ................................................................................................. 62 Plate 44 – Possible Roman paver (FN04). ................................................................................................. 62 Acknowledgements With thanks to Peter Jones for commissioning this programme of archaeological work and to Richard Lewis for recommending ArchaeoDomus for this project and for proofreading this report. Thanks to Karen Davies for proofreading the report. Abbreviations used in this report HER DAT-DM LPA NGR NMR OS BHT
- Historic Environment Record. - Dyfed Archaeological Trust Development Management - Local Planning Authority. - National Grid Reference. - National Monuments Record. - Ordnance Survey. - Brymbo Heritage Trust.
All other abbreviations will be referred to in text.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Project Team Ross Cook – A buildings archaeologist and dendrochronologist with a background in archaeology and buildings conservation. He has undertaken archaeological fieldwork throughout Wales and has also worked to produce detailed surveys of a wide range of Scheduled Ancient Monuments and Listed Buildings throughout Wales and England; this has included Neath Abbey, Llansteffan Castle, Tretower Castle, Cilgerran Castle, Newport Castle Pembrokeshire, Picton Castle, and Brymbo Ironworks. Ross is the Cathedral Archaeologist at St Davids Cathedral, Pembrokeshire. Previously, he has worked for the Royal Commission on the Ancient and Historical Monuments of Wales as a Historic Buildings Investigator (Archaeology), where he recorded buildings and Monuments, and provided advice on historic buildings at a national level. Currently he is involved with project work with Cadw, The Brymbo Heritage Group, and The Buildings of Medieval and Ottoman Palestine Research Project. Ross also works as an Associate Dendrochronologist with the Oxford Dendrochronology Laboratory, through which he has undertaken work on sites such as Hampton Court Palace, Winchester Cathedral, Queens House Greenwich, The Tower of London, Christ Church and Magdalen College Oxford, Llwyn Celyn (Mons), and a large number of other smaller listed buildings and scheduled sites throughout Wales and England. ArchaeoDomus Archaeological & Heritage Services is the trading name of Ross Cook. Ross Cook is an affiliate member of the CIfA, and adheres to the CIfA codes of conduct. Cert. in Buildings Archaeology – University of Sussex, CCE. PGCert. Social Anthropology – University of Wales, Lampeter BA Joint Honours Archaeology & Anthropology – University of Wales, Lampeter
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Pont Blaen Cwm Du, Libanus, Powys
Archaeological Record and Watching Brief Report
Summary ArchaeoDomus Archaeological & Heritage Services was commissioned by Peter Jones, on behalf of Powys Highways, to prepare a Written Scheme of Investigation, produce an Archaeological Record and undertake an Archaeological Watching Brief during works at Pont Blaen Cwm Du. The aim of this work has been to produce a record of the bridge prior to works and to allow for the development to be undertaken whilst monitoring for any potential archaeological resource. The works proposed the stabilisation and reinstatement of the bridge, which had suffered partial collapse caused by the undermining of the structure by floodwater. This collapse brought down the northern part of the arch vault, but left the elevations standing. The archaeological record was undertaken on 7th August 2020, which produced a photogrammetric model of the bridge and surrounding area, including the Tollgate House. The post-work record was undertaken on 2nd September 2020. The result of this work is presented in this report. The early commencement of works, without notification, meant that the proposed scope of the watching brief was reduced to monitoring the excavation of the south spandrel and the grading of the river bed. These took place on 26th August and 2nd September 2020, and identified no further archaeological features, deposits or structures. The watching brief identified that Pont Blaen Cwm Du is a bridge of a single phase of construction, with the only modification being the non-intrusive addition of low walls against the east elevation to form a sheep wash. The development of the bridge cames as part of the Swansea to Brecon Turnpike Road, begun in 1767. The bridge was built with an associated Tollgate House for the collection of tolls for the Breconshire Turnpike Trust. During the course of the watching brief several unstratified stone pavers were recovered from the stream to the east of the bridge. The shape and size of the limestone slabs made them identifiable as having been made as interlocking pavers, such as those used on Roman roads. When this is considered in relation to the suggested route of the Sarn Helen Roman road and the identification of dorsum/agger viae (stone surface) or umbones (kerb/edge stones) to the south of the bridge, their discovery adds to the body of evidence demonstrating Roman activity at this location.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Pont Blaen Cwm Du, Libanus, Sir Powys
Cofdod Archeolegol a bugeilio archaeolegol
Crynodeb Comisiynwyd Gwasanaethau Archeolegol a Threftadaeth gan Peter Jones, ar ran Priffyrdd Powys, i baratoi Cynllun Ymchwilio Ysgrifienedig, cynhyrchu Cofdod Archeolegol ac ymgymryd Brîff Gwylio Archeolegol yn ystod gweithiau at Pont Blaen Cwm Du. Nod y Gwaith hwn oedd i gynhyrchu cofnod o’r pont cyn gweithiau ac i caniatáu i’r datblygiad gael ei wneud wrth fonitro wrth fonitro am unrhyw adnodd archeolegol posib. Roedd y gwaith yn cynnig sefydlogi ac adfer y bont, a oedd wedi dioddef cwymp rhannol a achoswyd gan danseilio'r strwythur gan ddŵr llifogydd. Achosodd y cwymp hwn i ddod â rhan ogleddol claddgell y bwa i lawr, ond gadawodd y drychiadau i sefyll. Cafodd y cofnod archeolegol ei ymgymryd ar 7fed Awst 2020, a gynhyrchodd a model ffotogrammetrig o'r bont a'r ardal gyfagos, gan gynnwys y Ty Tollborth. Cafodd y cofnod cofnod ôl-waith ei ymgymryd ar 2il Medi. Cyflwynwyd canlyniadau y gwaith hwn yn yr adroddiad hwn. Roedd cychwyn y gwaith yn gynnar, heb hysbysu, yn golygu bod cwmpas arfaethedig gostyngwyd y brîff gwylio i fonitro cloddio spandrel y de a'r graddio gwely'r afon. Digwyddodd y rhain ar 26 Awst a 2 Medi 2020, a ni nodwyd unrhyw nodweddion, dyddodion na strwythurau archeolegol pellach. Nododd y brîff gwylio fod Pont Blaen Cwm Du yn bont o un cam o adeiladu, gyda dim ond ychwanegiad diymwthiol waliau isel yn erbyn y drychiad dwyreiniol ffurfio golch defaid. Daw datblygiad y bont fel rhan o’r Ffordd Dyrpeg Abertawe i Aberhonddu, wedi cychwyn yn 1767. Adeiladwyd y bont gyda Ty Tollborth cysylltiedig ar gyfer casglu tollau am Ymddiriedolaeth Tyrpeg Sir Frycheiniog. Yn ystod y brîff gwylio, adferwyd sawl palmant carreg heb haen o'r nant i'r dwyrain o'r bont. Siâp a maint y slabiau calchfaen a waned gellir eu hadnabod fel pe baent wedi eu cyd-gloi, fel y rhai a ddefnyddir Ffyrdd Rhufeinig. Pan ystyrir hyn mewn perthynas â llwybr awgrymedig y Ffordd Rufeinig Sarn Helen a huniaethiad dorswm/agger viae (wyneb carreg) neu ymbarelau (cerriant/ymyl) i'r de o'r bont, mae eu darganfyddiad yn ychwanegu at gorff y dystiolaeth sy’n arddangos gweithgaredd Rhufeinig yn y lleoliad hwn.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
1
INTRODUCTION
1.1
General
1.1.1
ArchaeoDomus was commissioned to undertake an archaeological programme of works, to include a Written Scheme of Investigation (ArchaeoDomus 2020), Archaeological Record and Watching Brief, during stabilisation and reinstatement works to the Pont Blaen Cwm Du, Libanus.
Fig. 1 – Pre-works photogrammetric elevations and vault of Pont Blaen Cwm Du.
1.1.2
Flooding in early 2020 caused part of the barrel to collapse, bringing the fill and roadway down, rendering the bridge unusable. Despite this damage, the voussoirs, spring and abutments remain intact.
1.1.3
This project has been commissioned by Peter Jones on behalf of Powys County Council under project number H3075. The bridge is number 213 and on highway U368.
1.1.4
As the project is under Highways’ jurisdiction, the emergency repairs for the maintenance of a public highway are covered by the Highways Act 1980, which confers powers to undertake such work without planning consent.
1.1.5
With consideration to the historic nature of the bridge and route, the Heritage Officer to the Brecon Beacons National Park, Alice Thorne, was consulted to make recommendations for archaeological recording and monitoring of works to the bridge, to be covered by a watching brief. Advice was provided on the 20th July 2020, which recommended an archaeological watching brief, which should seek to
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
‘a) record the current condition of the bridge, the sheep wash and the site of the turnpike cottage prior to works starting, and b) to monitor any areas of ground reduction, to ensure that any remains of archaeological significance disturbed in the course of the work are excavated, recorded and reported.’ (Email Communication with Peter Jones) 1.1.6
The commissioning of this archaeological programme of investigation was to enable stabilisation and repair works to commence, whilst making provision for an archaeological record. The outcome of the archaeological investigation is presented in this report as a record of the bridge and tollhouse prior to the commencement of works. Further evidence for the bridge’s development was collected during the watching brief, which monitored interventions to the bridge. The final report will be deposited with the National Monuments Record and Regional Historic Environment Record. This is designed to enhance our understanding of the monument and to produce a lasting record of such intervention works.
1.1.7
On 12th August it was communicated to ArchaeoDomus by Powys Highways that the contractor began work on site earlier than the date given to avoid adverse weather conditions forecast. This was planned and undertaken without informing Powys Highways and therefore resulted in no archaeological supervision. This resulted in large amounts of unsupervised landscaping works around the bridge to enable the rebuilding works to commence (Plate 17).
1.1.8
The unobserved works of 10th – 12th August 2020 included the following: ❖
Creation of a trackway from existing road to north of bridge down to river, including partial removal of boundary wall.
❖
Consolidation of track from river to road south of bridge, including partial removal of boundary wall to Tollgate House.
❖
Removal of stone from river bed.
❖
Removal of fill to north abutment of bridge.
❖
Clearance of stone from beneath bridge vault.
❖
Installation of temporary piped culvert under bridge.
1.1.9
On notification of the commencement of works, Powys Highways made contact for immediate attendance to site by the archaeologist for the 13th August 2020.
1.1.10
The fieldwork was commenced on 7th August 2020 and concluded on 2nd September 2020. It was undertaken in accordance with the guidance laid down by the Chartered Institute for Archaeologists; CIfA Standards and Guidance for an Archaeological Watching Brief (December 2014).
1.1.11
This report documents the results of the Archaeological Record and Watching Brief, and presents an assessment of the building’s development and use.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
2
SITE AND LOCATION
2.1
General
2.1.1
Pont Blaen Cwm Du is located towards the bottom of a small vale through which the Nant Cwmdu flows, meeting with the valley of the Afon Senni to the west. The vale sits with the slopes of Fran Frynych to the north and Rhos Dringarth to the south. The bridge forms part of an unclassified public highway, number U368, which is primarily used by walkers and farm traffic. An unclassified road runs north-south in the Afon Senni valley to the west. The settlement of Heol Senni lies 2.34km to the north-west, Libanus lies 6.75km to the north-east. Brychgoed Welsh Independent Chapel is the nearest place of worship, lying 3.9km to the north-west. Upland terrain surrounds the bridge, with a small copse of woods lining the river to the immediate west. The site sits at circa 378m above sea level and is centred around NGR SN 94237 21489 / 51°52'56.6"N 3°32'14.5"W / What3Words bulges.wiping.glorified.
Fig. 2 – Location – Pont Blaen Cwm Du. Contains Ordnance Survey OpenData © Crown copyright and database rights 2019.
Fig. 3 – Location – Pont Blaen Cwm Du. Contains Ordnance Survey OpenData © Crown copyright and database rights 2019.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
2.2
Geology
2.2.1
The underlying geology is formed of an interbedded argillaceous rock and sandstone formation known as the Senni Formation (BGS) glacial deposits, Devensian – Diamicton, sand and gravel superficial deposits recorded (BGS). The local soil type is a slowly permeable, seasonally wet, acidic loamy and clayey soil (UKSO), classified as a Stagnosols (UKSO).
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
3
HISTORICAL BACKGROUND
3.1
Introduction
3.1.1
This history focussed on the bridge and the likely historic development of the immediate area based on known and proposed history. It is undoubtable that the bridge is situated within a landscape of significant historical importance, with sites surrounding the location spanning from the prehistoric period to contemporary times.
3.1.2
The Royal Commission records the bridge under NMRW: 43100.
3.2
Historical Background
3.2.1
This historical background has been compiled from readily available sources.
3.3
Roman
3.3.1
The location of the current bridge and public highway is sited on the proposed route of the Sarn Helen Roman Road from Coelbren to Brecon Gaer as identified by the CPAT Roman Roads Project (2002-3). As part of this project, the possible embankment of the road was observed to the south of the bridge (PRN 14135), centring on SN 93760 21068, but was never positively identified. The discovery took the form of several large sandstones, which had been exposed by water, and may have been dorsum/agger viae (stone surface) or umbones (kerb/edge stones).
3.4
Post-Medieval
3.4.1
In 1752, an Act of Parliament enabled the formation of Turnpike Trusts in Wales for the purpose of enabling committees of gentry and others of vested interest to improve the main roads of a county. This allowed the trusts to borrow money and imbued trusts with the authority to compulsorily purchase land and to then charge users a toll to cover the costs of construction.
3.4.2
The Breconshire Turnpike Trust was formed by Act of Parliament (C60) enacted by George III in 1767. Bogart (2017) suggests that the Breconshire stretch of the Swansea to Brecon turnpike was begun at this time.
3.4.3
The turnpike is certainly in existence by the time of the OS surveyors’ maps of Llandovery, completed by Thomas Budgen in 1823. At this time, a building is shown next to the stream,
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
labelled ‘Cwmdu Gate’, indicating its use as a toll house. It is likely that the bridge was also in existence by this time. 3.4.4
Unfortunately, the bridge is not shown on the Tithe Maps as it is in an upland, and therefore unfarmed, area.
3.4.5
Following the Rebecca Riots across Mid and South Wales between 1839-1842, a Royal Commission was set up to investigate their causes. As part of this work, a map entitled ‘MAP of the TURNPIKE TRUSTS IN SOUTH WALES’ (Fig. 5) was produced, which shows the Swansea-Brecon turnpike road, though ungated. The map and report ultimately lead to the passing of the 1844 Turnpike Act, which consolidated the trusts to simplify the rate system.
3.4.6
The Cambrian, 26th July 1823 edition, gives notice that the tolls arising from several tollgate houses were to be let by public auction on 29th September 1823, of which number 11 is Cwmdu Gate (Fig. 4).
3.4.7
A rent agreement from 13th August 1828 lists Cwmdu as one of several tollhouses rented out by the Breconshire Turnpike Trust (NLW: 1243. vtls005355961 - ISYSARCHB19). These rents gave the tenant the right to collect tolls from the road, for the right to keep part of the profits.
3.4.8
On 11th September 1839, the Rents of the Cwmdu Gate in Defynnock are bought at auction by John Harvard of Senny, innkeeper, and William Havard of Sclydack, farmer, under the trusteeship of H. S. Wood (Brecon Museum: A81/1/3:51).
3.4.9
Ordnance Survey First and Second Edition 25-inch maps of 1887 and 1904, (Fig. 6-7) show the bridge, along with the toll house, labelled as ‘Pont Blaen-cwm-dû’. In 1887, the hillsides above the road are showed as pine forestry, which has been cleared by the 1904 edition. Apart from this, there has been little change since.
3.4.10
From local evidence gathered by P.L. Pearson as part of his 1962 thesis A Survey of Craig Cerriggleisaid National Nature Reserve, he records that a local resident recalls someone living in the property at the turn of the 20th century, but the house fell empty by 1903. The Ordnance Survey 25-inch mapping supports this.
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Fig. 4 – The Cambrian, 26th July 1823.
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Fig. 5 – Map of the Turnpike Trusts in South Wales, 1843. Red circle showing location of Blaen Cwm Du.
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4
AIMS AND OBJECTIVES
4.1
Watching Brief
4.1.1
The aims of the Watching Brief, as defined by the CIfA (2008; revision 2011), are: ‘To allow a rapid investigation and recording of any archaeological features that are uncovered during the proposed groundworks within the application area. To provide the opportunity, if needed, for the watching archaeologist to signal to all interested parties, before the destruction of the material in question, that an archaeological find has been made for which the resources allocated to the watching brief are not sufficient to support the treatment to a satisfactory or proper standard.’
4.1.2
The aims of the watching brief are to identify and record any potential archaeological remains or deposits during groundworks on site.
4.1.3
The watching brief will also seek to identify evidence, or lack thereof of, for the archaeological remains, deposits or finds associated with the development of the site.
4.2
Results
4.2.1
The objective of the historic buildings record is to produce a permanent record of the site and to place this within a public domain through deposition with the Regional HER and the National Monuments Record of Wales.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
5
METHODOLOGY
5.1
Introduction
5.1.1
All archaeological works have been conducted by a qualified archaeologist, or under the direction of the qualified archaeologist, in accordance with the methodology set out in the Written Scheme of Investigation (ArchaeoDomus 2020) and in line with the Standards and Guidance from the Chartered Institute for Archaeologists.
5.2
Survey Record
5.2.1
A photogrammetric survey of the bridge was made prior to commencement of works. The on-site survey produced a set of photographs captured using a DJI Mavic 2 Pro (drone), to enable image capture from all angles. Ground control points were tied into the National Grid using RTK-GPS, which also provided dimensional control and ensured accuracy. The photogrammetric model was then processed in Agisoft Metashape and drawings produced in CAD.
5.2.2
Drawings were produced at a scale of 1:1 in CAD and supplied at 1:50 at A2 in PDF and DXF formats.
5.2.3
The drawn record has been appended to this report (Appendix II)
5.3
Photographic Recording
5.3.1
A photographic record was made of the bridge, which included: ❖ General views of the bridge and its surroundings. ❖ All elevations. ❖ Record of interventions.
5.3.2
The photographic record has been compiled into an archive, which has been appended to this report (Appendix III).
5.3.3
Photographs were taken with a standard Canon 760D 24-megapixel camera with 18-50mm standard or 10-22mm wide angle lens, a DJI Mavic 2 Pro or by mobile phone, with sensors no less than 13 megapixels.
5.3.4
All photographs have been named using the project code, in this instance AD092, which are followed by a reference and number. The reference codes used are as follows:
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
❖ BW – Before works ❖ DW – During works ❖ PW – Post works ❖ SF – Small Find 5.3.5
All photographs in this report are watermarked with the photograph’s name, code and number.
5.4
Reinstatement
5.4.1
Once development has been completed, the stone was used to grade the river bed and provide erosion protection to the banks.
5.5
Documentary Research
5.5.1
Documentary research was undertaken using readily available resources with additional research aided by map regression and Tithe Map searches. Historic trade directories were used to help establish a timeline of events for the site. Further research was undertaken using unpublished and published sources.
5.6
Reporting
5.6.1
This report has been written and compiled by Ross Cook, in line with the guidance provided by CIfA’s Standards and Guidance for an Archaeological Watching Brief (December 2014)).
5.6.2
This report has been written in Microsoft Word 2016 and uses Adobe Garamond Pro as its typeface.
5.7
Health and Safety
5.7.1
All work was carried out in accordance with the Health and Safety at Work Act 1974 and Health and Safety Advice in Archaeology (BAJR 2005).
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6
PHOTOGRAMMETRY METHODOLOGY AND OUTPUT
6.1
Introduction
6.1.1
The survey of Pont Blaen Cwm Du was undertaken on 7th August 2020.
6.1.2
The aim of the survey was to capture the monument using controlled 3D capture (photogrammetry), to enable the production of high-resolution orthographic images of the bridge and its surrounding area prior to the commencement of works.
6.2
Method
6.2.1
The structure was captured using a UAV (drone) equipped with a 35mm equivalent 20mp camera, with 1 inch sensor. Additional photographs were taken using a Canon 760D. Manual settings, including ISO, f/stop and exposure were altered during recording to enable the highest quality images for modelling.
6.2.2
Ground control points (GCPs) were set around the monument and their position tied into the Ordnance Survey National Grid using RTK-GNSS, consisting of base station and rover with datalogger.
6.2.3
All photographs include geographic coordinates, collected by the drone’s onboard GPS sensor and stored with the image’s metadata.
6.2.4
All photographs were taken by drone over four consecutive flights. The use of a drone enabled the capture of the monument from all angles, including vaulting of the bridges arch.
6.2.5
Models were produced using proprietary photogrammetry software, into which 455 photographs of the monument were loaded for processing; Sparse point cloud –> Dense point cloud –> Mesh –> Texture –> Orthomosaic.
6.2.6
Dimensional control was then applied to the processed model using the coordinates collected from the ground control points. The model was then reprocessed using the new parameters and optimised cameras, which produced a model with overall dimensional error of 1.5mm.
6.2.7
High face count meshes were produced to retain the integrity of the original object, and then textured to 25,000 pixels (OBJ).
6.2.8
On completion of each model, models were exported to OBJ format. Orthographic renders were exported and scaled in JPG format.
6.2.9
Scaled output from this is appended to this report (Appendix III) 13
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
6.3
Results
AD092 – Pont Blaen Cwm Du Photogrammetric Model Photographs
File Size
Dense Point Cloud
783
16.44 GB
83,770,025 points
Mesh Face Count
Texture Size (pixels)
Total Point Error (mm)
13,986,670
25,000 x 25,000
1.5mm
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
7
ARCHAEOLOGICAL RECORD
7.1
Introduction
7.1.1
This section provides a descriptive and phased account of Pont Blaen Cwm Du.
7.1.2
The bridge spans a minor watercourse called the Nant Cwm-du, which channels water runoff from the Fran Frynych and Rhos Dringarth hills to the east.
7.1.3
Despite the worn and rough nature of the track leading to the bridge, both form part of Public Highway U368.
7.1.4
The survey record is available in Appendix II and the photographic record in Appendix III.
7.2
Description (Plates 1-8; Fig. 13)
7.2.1
Pont Blaen Cwm Du is simple in form, comprising a single span bridge, projecting from abutments to the north and south banks of the stream at the start of a small ravine.
7.2.2
Wing walls run away to the north and south at gentle angles from the bridge, and in doing so retain the roadway on the approaches to the bridge.
7.2.3
The bridge’s segmental arch and plain spandrels are recessed from the elevations of the wing walls and low roadway wall (Plates 3-4). The voussoirs of the arch are undressed, but neatly shaped, and rise from spring stones that extend from the wings.
7.2.4
The segmental vault is finished to the north and south elevation by large, hammer-dressed limestone voussoirs (Plate 29), neatly formed with narrow mortar joints between.
7.2.5
The bridge is constructed of roughly squared limestone blocks, which are coursed with occasional risers spanning several courses.
7.2.6
Stonework is bonded in a lime mortar with small to medium aggregate of angular, subangular and round stone, with frequent elements of unslaked limestone.
7.2.7
The roadway is covered in a layer of mixed earth and stone, with a surface layer of fine stone gravel (Plate 20).
7.2.8
A sheep wash, built sometime in the 20th century of red brick and limestone, is built against the east elevation (Plate 2, 5, 6 and 7; Fig. 13). A groove in this indicates where a gate was inserted to restrict the flow of the river to create a pool for washing sheep.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
7.2.9
The Tollgate House (Fig. 13) survives as a series of low wall stubs to the south of the bridge, set back into the rising slope of the hillside. The plan is formed of two units, one comprising the main part of the cottage to the south-west and a second added to the north-east is likely a small addition. The original part of the cottage appears to have been divided into two bays. From the north end of the building, a wall runs north-west and connects with the bridge.
7.3
Development
7.3.1
Phase 1 – circa 1767: Pont Blaen Cwm Du is of a single phase of development, having been constructed in or just after 1767, when the construction of the Swansea to Brecon Turnpike was begun. The construction of the Tollgate House was concurrent with the bridge.
7.3.2
Phase 2 – Early 20th Century: The addition of two low walls to the east elevation created a sheep wash, and was the only alteration to the bridge throughout its 250-year history.
7.4
Damage
7.4.1
In early 2020, the bridge suffered a catastrophic failure of the vault, caused by erosion undermining the northern abutment (Plates 3, 4, 8 and 9; Fig. 13). The cause was identified as being the directional change in the flow of the river by the sheep wash walls, directing the flow against the north abutment causing erosion and undermined this.
7.4.2
Despite this, the remaining structure of the bridge survived the collapse in remarkably good condition, with both east and west elevations surviving intact and undamaged.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
8
WATCHING BRIEF RESULTS
8.1
Introduction
8.1.1
In this section the results of the Watching Brief are presented. The extent of the excavations is shown in Appendix II (Fig. 9), and the photographic archive in Appendix III.
8.1.2
Resulting from the early commencement of stabilisation and reinstatement works, the planned programme of monitoring was not completed, covering areas E1, E2 and E3 (Fig. 9). However, an archaeologist was present for all remaining groundworks (Fig. 9; T1, T2).
8.1.3
The watching brief was undertaken on 26th August and 2nd September 2020, and monitored the excavation of the southern spandrel and the grading of the riverbed.
8.2
Archaeological Results
8.2.1
Context numbers have been attributed to the stratigraphic sequence and are presented below in the corresponding subsection.
8.2.2
Five possible Roman road (FN01-04; Plate 41-44) or ford pavers were discovered, which were identified in the stream to the east of the bridge during the initial survey. It is not clear where in the stream these originated from and they may have been brought downstream by flooding. The pavers were recovered after the stream was disturbed by machine work between 10th – 12th August 2010 (section 1.1.9).
8.2.3
Four unstratified sherds of willow pattern were recovered from the spoil on the bank to the north of the former Tollgate House, after this area was disturbed by machine work between 10 th – 12th August 2020 (section 1.1.9).
8.3
Site Meeting – 13th August 2020
8.3.1
On notification of the early commencement of works, arrangements were made for a site meeting on 13th August 2020. This meeting allowed for the assessment of ground disturbance works (Fig. 13, E1, E2 and E3) and to record any archaeological materials or features exposed by the works.
8.3.2
The works excavated material from the north abutment to prepare for new foundations to support reinstatement works. This excavation appears not to have disturbed any archaeological features, structures or deposits and only removed the bridge’s fill material.
8.3.3
Excavations had disturbed the river bed, to allow for the installation of a pipe to channel water during the course of works to enable reinstatement works to commence. As such, the limestone 17
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
pavers observed during the survey had been disturbed. These were unstratified before the works, and assessment of the riverbanks did not provide any evidence of further material or structures. Five pavers were recovered from the riverbed. 8.3.4
Tracking and machine work to the south bank disturbed the bank and south boundary wall of the Tollgate House. This was recorded photographically.
8.3.5
No further archaeological finds, materials, features or deposits were identified.
8.4
Excavation of Southern Spandrel – 26 t h August 2020 – Plates 28-20
8.4.1
On reinstatement of the collapsed vault, the surviving southern spandrel was excavated (Fig. 13, T1) to allow for concrete reinforcement to be poured onto the stone vaulting.
8.4.2
Excavations began with the removal of the surface material (101), which exposed the sub-surfacing (103). These overlie the fill material (104), which rested directly on the vault (105). To the edges of the roadway, overgrowing the roadway surface, grass and lesser vegetation has formed a layer of humus (102).
8.4.3
The stratigraphic sequence is recorded below.
Bridge Fill Material (T1)
8.4.4
Context
Type
Depth
Description
101
Deposit
0.000.11m
102
Natural
Roadway surface. Small stone aggregate, bonded with earth. Occasional medium stone inclusions. Overlies 103. Natural humus. Overlies 101 and 103.
103
Deposit
104
Deposit
105
Structure
0.000.20m 0.110.63m 0.63NB -
Sub-surface. Medium angular and subangular stone hardcore, bonded with earth. Overlies 104. Stone and earth fill. Small to large angular stone in earth matrix. Overlies 105. Limestone vault of bridge. Bonded in lime mortar and secured by fill.
No further archaeological finds, materials, features or deposits were identified.
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Period 18th-19th Century Modern 18th Century 18th Century 18th Century
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
8.5
River Grading – 2 n d September 2020 – Plates 36-39
8.5.1
On completion of works, it was intended that the river bed should be graded to graduate the stream to and under the bridge, using materials moved at the start of the project. However, heavy rain caused flooding, which carried much of the material downstream. Instead, excess stone from the stabilisation and reinstatement works was used to provide protection to the south bank at the approach to the bridge to reduce the risk of erosion. The north bank was cleared of material deposited during the unmonitored works and relevelled with in situ material after machine tracking during works. Therefore, no archaeological finds, materials, features or deposits were identified.
8.5.2
No stratigraphy was recorded.
8.5.3
No archaeological finds, materials, features or deposits were identified.
8.6
Finds Assemblage
8.6.1
Despite no finds being recovered during the course of the watching brief, a finds assemblage was recovered from the disturbed ground to the Tollgate House and from the riverbed upstream of Pont Blaen Cwm Du. These finds have been assessed and recorded by ArchaeoDomus and presented in the table below:
Context
Material
No.
Wt (g.)
Comments
UNSTRAT
Stone
4
-
UNSTRAT
China
4
54g
Limestone pavers. Recovered from riverbed. Roman or Early Medieval ford crossing. FN01-04. China sherds. Willow pattern. 19th or 20th century.
8.6.2
Given the nature of the finds, no further work has been undertaken.
8.6.3
No further archaeological finds were recovered.
8.7
Environmental
8.7.1
No environmental deposits for sampling were identified.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
9
DISCUSSION
9.1.1
From the investigations on site, the evidence demonstrates Pont Blaen Cwm Du is a bridge of a single phase of construction, with only the non-intrusive addition of low walls against the east elevation to form a sheep wash. The development of the bridge came as part of the Swansea to Brecon Turnpike Road, begun in 1767. The bridge was built with an associated Tollgate House for the collection of tolls for the Breconshire Turnpike Trust.
9.1.2
The Turnpike and bridge are thought to occupy part of the proposed route of the Sarn Helen Roman Road from Coelbren to Brecon Gaer, as identified by the CPAT Roman Roads Project (2002-3). As part of this project, the possible embankment of the road was observed to the south of the bridge (PRN 14135), centring on SN 93760 21068. The discovery took the form of several large sandstone blocks, which had been exposed by water, and may have been dorsum/agger viae (stone surface) or umbones (kerb/edge stones). At the time these were never positively identified as being Roman in origin.
9.1.3
The four possible pavers (FN01-04; Plates 41-44) distinguished themselves from the surrounding limestone through their shape and form, being flat and irregular in shape. The appearance of these, being polygonal in shape, lend themselves to being interlocking dorsum or agger viae (road surfacing). Whilst it is unlikely that these formed the surface of any large stretches of the road, they may form the approach or bed of a ford for crossing the Blaen Cwm Du at this shallow and accessible point. If the pavers recovered from the stream are indeed Roman, when considered in relation to the information above, it adds to the body of evidence supporting Roman activity at and around Blaen Cwm Du.
9.1.4
During the course of the watching brief, no finds, materials, features or deposits were identified further to the items recovered after the commencement of works (8.5.1). Deposits observed within the banks of the stream were those consistent with water course scouring. These were assessed for the potential survival of archaeological materials relating to the structure of a Roman road, but nothing was observed. This is the result of seasonal flooding, which is likely to have disturbed all such deposits and structures.
9.1.5
The Tollgate House survives in poor condition, with its general plan discernible through its series of low walls. The condition of the ruins has deteriorated significantly from the account given by Pearson in 1962, when the internal plan of the dwelling was still identifiable. Despite this, the general form of the dwelling is identifiable, with the original cottage and extension to the northeast. The documentary evidence, from newspapers and rent accounts, demonstrates that the Turnpike house was profitable despite its relatively isolated position. This profitability was sufficient enough to enable the rights to the rent to be successfully auctioned on a number of occasions.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
10
ARCHIVING
10.1
The results of the Historic Buildings Record and Watching Brief are this written report, interpreted survey, and photographic archive. This will be held by and will be deposited with the regional HER and the NMR. A PDF copy of the report will be made available from www.archaeodomus.co.uk.
11
SOURCES
11.1
Written Sources
11.1.1
Bogart, D. Undated. The Turnpike Roads of England and Wales. Cambridge University.
11.1.2
Cary, J. 1828. Cary's Traveller's Companion, Or, a Delineation of the Turnpike Roads of England and Wales. Facsimile Edition, 2010. Gale Ecco, UK.
11.1.3
Pearson, P. L. 1962. A Survey of Craig Cerrig-gleisaid National Nature Reserve. UCL Diploma of Conservation Thesis. London.
11.1.4
CIfA, 2014, Standards and guidance for the archaeological investigation and recording of standing buildings or structures.
11.1.5
CIfA, 2014, Standards and guidance for an archaeological watching brief.
11.1.6
Welsh Government, 2017, Planning Policy Wales; Technical Advice Note 24: The Historic Environment. Crown Copyright.
11.2
Online Sources
11.2.1
British Geological Survey Accessed: July 2020 www.bsg.ac.uk
11.2.2
UK Soil Observatory Accessed: July 2020
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
www.ukso.org.uk
11.3
Maps
11.3.1
1887 OS 25 Inch to One Mile Map First Edition
11.3.2
1904 OS 25 Inch to One Mile Map Second Edition
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
APPENDIX I
Historic Mapping
23
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Fig. 6 – 1887 25-inch to One Mile, OS. © Landmark Information Group Limited 2020.
Fig. 7 – 1904 25-inch to One Mile, OS. © Landmark Information Group Limited 2020
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
APPENDIX II
Survey Record
1
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Fig. 8 – Orthomosaic – Pont Blaen Cwm Du. 38
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Pont Blaen Cwm Du Excavations
E1 E3
T1
T2
E2
Fig. 9 – Excavation areas – Pont Blaen Cwm Du. 39
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Fig. 10 – Assets – Pont Blaen Cwm Du. 40
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Fig. 11 – Height Map – Pont Blaen Cwm Du. 41
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Fig. 12 – Height Map Assets – Pont Blaen Cwm Du. 42
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Fig. 13 – Elevations – Pont Blaen Cwm Du.
43
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
APPENDIX III
Photographic Archive
40
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 1 – Pre-works – West elevation of bridge.
Plate 2 – Pre-works – East elevation of bridge. 41
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 3 – Pre-works – Collapse of roadway, viewed towards south.
Plate 4 – Pre-works – Collapse of roadway – view towards south. 42
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 5 – East elevation, showing walls of sheep wash.
Plate 6 - North sheep wash wall, showing groove for sluice gate.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 7 - - South sheep wash wall, showing groove for sluice gate.
Plate 8 – Arch vault, showing south abutment, vaulting and collapse.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 9 – Arch vault, showing collapse.
Plate 10 – Pre-works – Fill of spandrel to bank, north bank. Photo turned 90° anticlockwise.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 11 – Pre-works – Possible paver found in stream to east of bridge.
Plate 12 – Pre-works – Possible paver found in stream to east of bridge.
46
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 13 – Pre-works – Possible paver found in stream to east of bridge.
Plate 14 – Watching Brief – Spandrel fill to north bank, after partial excavation.
47
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 15 – Watching Brief – Internal face of north-west spandrel and arch.
Plate 16 – Watching Brief – Internal face of north-east spandrel and arch, with sheep wash wall behind.
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 17 – Watching Brief – Surviving portion of north-west arch and abutment.
Plate 18 – Watching Brief – 20th century concrete plinth to east end of north abutment.
49
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 19 – Watching Brief – Threshold between sheep wash (east) and underside of bridge (west).
Plate 20 – Watching Brief – South wall of sheep wash, after removal.
50
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 21 – Watching Brief – Area of grading and track damage to north-east wall of Tollgate House.
Plate 22 – Watching Brief – Works undertaken without archaeological monitoring.
51
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 23 – Watching Brief – South abutment, showing stonework plinth and roughly dressed blocks.
Plate 24 – Watching Brief – South abutment after riverbed clearing.
52
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 25 – Watching Brief – Roadway, showing voussoirs and fill.
Plate 26 – Watching Brief – Concrete filled hessian sack, part of sheep wash construction.
53
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 27 – Watching Brief – Boundary wall, cut through without archaeological monitoring.
Plate 28 – Watching Brief – Spandrel excavation, showing vault and internal face of west spandrel.
54
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 29 – Watching Brief – Spandrel excavation, showing vault and internal face of east spandrel.
Plate 30 – Watching Brief – View north, showing arch and iron reinforcement for concrete pour.
55
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 31 – Watching Brief – Completed rebuild of north abutment and arch, viewed west.
Plate 32 – Watching Brief – Completed rebuild of north abutment and arch, viewed west. 56
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 33 – Watching Brief – Completed rebuild of north abutment and arch, viewed north.
Plate 34 – Watching Brief – Completed rebuild of north abutment and arch, viewed east. 57
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 35 – Watching Brief – West elevation on completion of reinstatement.
Plate 36 – Watching Brief – East elevation on completion of reinstatement. 58
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 37 – Watching Brief – End of works clean and grading of north bank.
Plate 38 – Watching Brief – View west downstream, showing clean and grading of banks. 59
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 39 – Watching Brief – View of south bank, showing clean and grading of bank.
Plate 40 – Watching Brief – View south, showing new surfacing to roadway.
60
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 41 – Possible Roman paver (FN01).
Plate 42 – Possible Roman paver (FN02).
61
Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
Plate 43 – Possible Roman paver (FN03).
Plate 44 – Possible Roman paver (FN04).
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Pont Blaen Cwm Du Archaeological Record & Watching Brief Report AD092 – November 2020
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