The Iron Bridge: Archaeological Monitoring of Trial Holes

The Archaeology Unit of the Ironbridge Gorge Museum Trust Final Report (Ironbridge Archaeological Series No.197) Archaeological Monitoring of Trial Holes Excavation January 2007 Report by Simon Roper, Sophie Watson, Shelley White & Paul Belford Prepared for English Heritage 23 Savile Row London W1S 2ET Ironbridge Archaeology – Final Report Contents Figures……….......................................................................................................... iii Plates ……………………………………………………………………………………..iii Acknowledgments ................................................................................................... iv Summary..................................................................................................................... 5 1 INTRODUCTION ................................................................................................. 6 1.1 Site Location and Description...................................................................... 6 1.2 Project and Planning Background ............................................................... 6 2 HISTORICAL BACKGROUND............................................................................. 8 3 METHODOLOGY............................................................................................... 11 4 2.3.1 The Written Record ............................................................................... 11 2.3.2 The Drawn Record ................................................................................ 11 2.3.3 The Photographic Record...................................................................... 11 RESULTS .......................................................................................................... 13 4.1 Hole 1 ........................................................................................................ 13 4.2 Hole 2 ........................................................................................................ 13 4.3 Hole 3 ........................................................................................................ 13 4.4 Hole 4 ........................................................................................................ 15 4.5 Hole 5 ........................................................................................................ 15 4.6 Hole 6 ........................................................................................................ 15 4.7 Hole 7 ........................................................................................................ 16 4.8 Hole 8 ........................................................................................................ 16 4.9 Hole A........................................................................................................ 16 4.10 Hole B........................................................................................................ 17 4.11 Hole C ....................................................................................................... 17 4.12 Hole D ....................................................................................................... 18 4.13 Hole E........................................................................................................ 18 Ironbridge Archaeology – Archaeological Monitoring on The Iron Bridge January 2007 i Ironbridge Archaeology – Final Report 5 4.14 Hole F........................................................................................................ 18 4.15 Hole G ....................................................................................................... 19 4.16 Hole H ....................................................................................................... 19 4.17 Hole I ......................................................................................................... 20 4.18 Hole J ........................................................................................................ 20 CONCLUSION ................................................................................................... 21 Ironbridge Archaeology – Archaeological Monitoring on The Iron Bridge January 2007 ii Ironbridge Archaeology – Final Report FIGURES Figure 1: Location Plan ............................................................................................... 7 Figure 2: Hole no. 3................................................................................................... 14 Figure 3: Hole no. 4................................................................................................... 14 Figure 4: Hole no. 5................................................................................................... 15 Figure 5: Bolt (063) from Hole A on outer side of bridge........................................... 16 Figure 6: Bolt (070) from Hole B on outer side of bridge........................................... 17 Figure 7: Hole C, iron post (071) sitting between two fascia plates (072) & (073) .... 18 Figure 8: Hole F, iron post (084) sitting between two fascia plates (085) & (086) .... 19 PLATES – located at rear of report Plate i: Location Plan of Holes Plate ii: Excavations 1- 4 Plate iii: Excavations 5-8 Plate iv: Excavations A - J Ironbridge Archaeology – Archaeological Monitoring on The Iron Bridge January 2007 iii Ironbridge Archaeology – Final Report ACKNOWLEDGMENTS The project was managed by Paul Belford. Site visits were undertaken by Shelley White and Keith Hinton. The report was written by Simon Roper Sophie Watson, Shelley White and edited by Paul Belford A copy of this report, all field drawings, notebooks and photographs will be archived with an appropriate repository (to be confirmed). All archive materials are in accordance with the requirements of the United Kingdom Institute of Conservators (UKIC). A copy of the report will be retained by Ironbridge Archaeology in the Long Warehouse, Coalbrookdale. © 2007, Ironbridge Gorge Museum Trust Copies are available on request from: Ironbridge Archaeology Ironbridge Gorge Museum Trust Ironbridge Telford TF8 7DQ Tel: Fax: +44 (0)19 52 43 59 45 +44 (0)19 52 43 59 37 e-mail: archaeology@ironbridge.org.uk Ironbridge Archaeology – Archaeological Monitoring on The Iron Bridge January 2007 iv Ironbridge Archaeology – Final Report SUMMARY The excavations on the Iron Bridge were undertaken in November 2006. They formed part of a research agenda organized by English Heritage to ascertain the nature of sub-surface fixings to the upright railing posts – Holes A – J, and by a further series of small excavations – Holes 1-8, to establish the extent of water ingress through the road deck level and its effect on the condition of the cast iron deck plates. No stratified artefacts were uncovered within the stratified layers to aid in the dating of the sub-surface remains and fittings. The dating of the fittings is based on the technological expertise seen elsewhere on the bridge and from documentary evidence. Excavations have proven the deck plates on the Secondary arches S1 and S2 are of a different cast form than those on the main and original arch of the bridge. This is a consequence of the secondary arches being constructed at a later date in 1821. Further they are bolted together. Water ingress through the road deck level was found to have occurred, and had collected above the flanged deck plates of the secondary arches. The water ingress which had occurred through the road deck level above the main arch had seeped away. The excavations undertaken to expose the sub-surface fittings on the railings posts uncovered a variety of different fittings. Those seen on the secondary arch were thought to be original to its construction, although examination of more post fittings would be required to prove this. A number of post fittings on the main arch had been subject to failure. However, it is thought all those fittings encountered pre-date the replacement of the road deck level which including the pavement and curbs of the 1970s. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 5 Ironbridge Archaeology – Final Report 1 INTRODUCTION 1.1 SITE LOCATION AND DESCRIPTION The Iron Bridge is a scheduled Ancient Monument County No. 106, National No.27558. The bridge is also a Grade 1 Listed Building and forms a prominent landmark at the centre of the Ironbridge Gorge, Shropshire. The bridge is owned by English Heritage and is a guardianship monument. The Iron Bridge lies on the River Severn at grid reference SJ 6723 0338 (Fig 1). 1.2 PROJECT AND PLANNING BACKGROUND Ironbridge Archaeology was contracted by English Heritage to undertake a watching brief on the Iron Bridge in conjunction with structural investigations. The investigations were undertaken to ascertain the extent of water ingress and the corrosion of the cast iron deck plates forming the base of the road level on all the bridge arches. In addition, investigations as to the nature of the sub-surface railing post fittings were also undertaken. Prior to this contract the Iron Bridge has been subject to structural analysis and recording in 2000 and 2001. These contracts also undertaken by Iron Bridge Archaeology, recorded the substructure and superstructure of the bridge, detailing any information associated with the formation of the single span bridge, later alterations, and additions, such as the secondary arches. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 6 Ironbridge Archaeology – Final Report Figure 1: Location Plan Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 7 Ironbridge Archaeology – Final Report 2 HISTORICAL BACKGROUND The Iron Bridge was built in 1779 and was the first single span bridge to be formed wholly from cast iron. It was possibly cast at one of the Coalbrookdale Furnaces, under the ownership of the Coalbrookdale Company. The company had been founded earlier in the eighteenth century in an area rich in mineral resources. Coal, ironstone and clay were all extracted locally and used in iron, ceramic and other industries, some established in the early seventeenth century. The later half of the eighteenth century saw a large scale development of the Shropshire and Welsh iron industry. The considerable expansion of the Dale Company continued in the 1750s, which was overseen by Abraham Darby II. The Dale Company erected new blast furnaces at Horsehay in 1755 and 1757 and at Ketley in 1757. The use of iron in structures had been used since prehistory, however, to construct a single structure of cast iron which was almost self supporting, an Iron Bridge, turned into the vision of Abraham Darby III. This would raise awareness of the work of the Coalbrookdale Co. and thus enhance the company’s competitiveness. By 1773, the idea of building a bridge across the Severn had already been under active consideration. The first proposal being in a letter from the Shrewsbury Architect, Thomas Farnolls Pritchard to John Wilkinson, an ironmaster of the New Willey Company, located on the Benthall side of the River Severn (Trinder, 1981, 106). In the March of 1776 An Act of Parliament gave royal assent for a toll bridge (16 Geo. III Cap XVII), "an act for building a Bridge across the River Severn from Benthall, in the County of Salop, to the opposite Shore in Madeley Wood, in the said County; and for the making of proper Avenues or roads to and from the same". The preamble also names those areas which will benefit from the use of the bridge; "Whereas a very considerable Traffick is carried on at Coalbrook Dale, Madeley Wood, Benthall, and Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 8 Ironbridge Archaeology – Final Report Broseley….and the persons carrying on the same are put to great Inconveniences, Delays and Obstructions, by reason of the Insufficiency of the present ferry over the River Severn from Benthall to Madeley Wood, commonly called Benthall Ferry." The personal account books of Abraham Darby III note expenditure on the Bridge project from 1776 to 1781. Archive evidence suggests the erection of the bridge began in the July of 1779, when the river water was at its lowest. The bridge was opened to traffic in 1781. Even before the bridge was constructed it was celebrated as a radical new application of technology. In the eighteenth and nineteenth centuries it attracted curious visitors from all over the world. Following the construction of the bridge the settlement of Ironbridge developed on the northern bank of the River Severn, initially strung along the River wharfage and then spreading toward the north. In 1934 the Iron Bridge was deemed to represent a significant point in design and technology. It had retained its original integrity to such an extent that it was recognized as nationally important and thus warranted statutory protection, the Iron Bridge was scheduled on 18th January 1934. The sheer expanse of iron, the craftsmanship, the locality and the design, all add to the rarity of this class of monument and form the reasons for the bridge being considered of such national importance. Forty years later further protection was warranted and the bridge was placed under the guardianship of the Secretary of State for National Heritage on the 29th October 1975; subsequently English Heritage. The bridge lies at the centre of an historic landscape of mining and related industries. The north bank comprises many furnace sites and engine houses, mills, maltings, houses, transport systems, warehouses and so on, whilst the south bank comprises large expanses of clay and coal mining, ceramic industries and transport systems, from early inclines and rails to the Severn Valley Railway. However, today the bridge is used for foot traffic only. Vehicular access was disallowed in 1934, tolls were abolished in 1950 and the bridge is now viewed as a prominent historic landmark, visited and photographed by approximately 270,000 people a year. In 1986 the Ironbridge Gorge achieved designation as a World Heritage Site. The Ironbridge lies at the centre of the World Heritage Site and as Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 9 Ironbridge Archaeology – Final Report such forms a major part of the World Heritage Site Management plan and requires regular management by the statutory body. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 10 Ironbridge Archaeology – Final Report 3 METHODOLOGY 2.3.1 The Written Record The written record comprised entries in a site notebook cross-referenced to pro-forma structure recording sheets. The written record of the building recording is intended to supplement the drawn and photographic records and will comprise: • • • • an overall description of the structure component-specific descriptions on pro-forma sheets (context sheets) lists and registers of drawings, levels and photographs further notes and records as required Items in the written record will be cross-referenced to the other components of the record, namely photographic and drawing. 2.3.2 The Drawn Record The drawn building record is comprised principally of hand-measured survey. Drawings were made by pencil onto waterproof drawing film. Drawings were indexed and numbered to enable cross-referencing within the drawing sequence and with other records. Building Recording was undertaken following the IFA Standards and Guidance, and in line with the published RCHME guidance, Recording Historic Buildings: a descriptive specification. 2.3.3 The Photographic Record. Most record photography was undertaken using a Pentax 35mm SLR cameras with standard (50mm lenses). Natural light was used wherever possible at all times. The principal record was made on colour print film with an ISO rating of 200, and black and white transparency film with an ISO rating of 100. In addition digital photography was taken on an Olympus FE 110 with 5.0 Megapixels. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 11 Ironbridge Archaeology – Final Report All photographs were recorded on site using a pro-forma Photograph Record Sheet, and cross referenced to the written and drawn records. All photographs contain a scale, either a 30cm scale with 10cm gradations, For detail photographs a smaller scale, with 1cm gradations, was used. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 12 Ironbridge Archaeology – Final Report 4 RESULTS Holes 1 to 8 were undertaken to ascertain the extent of water ingress within the road deck level, whilst Holes A to J were undertaken to ascertain the nature of the sub-surface fittings on the railing posts. Holes 1 and 2 were located above the northern extent of the main arch. Holes 3 and 4 were located above the southern extent of the main arch. Holes 5 and 6 were located above the first side arch and holes 7 and 8 were located above the second side arch. 4.1 HOLE 1 Excavation of Hole 1 exposed a build up of relatively recent layers above the deck plates (006). At the base of the hole was cast iron deck plate (006) which had no flanges visible. Partially covering the deck plate was a strip of 1950’s flash-band tape (005), used to cover joints between deck plates. Above these was a 20th century asphalt layer (004), 0.11-0.28 m thick. On the west side of hole 1 another layer of asphalt/tarmac (002) sat above (004), on top of which a 21st century gravel ‘crust’ (001) had been laid by English Heritage. On the east side of hole 1 a pale loose sand (003) sat above (004) in the cut of a trench for the insertion of cast iron curbs (007). 4.2 HOLE 2 Hole 2 followed the same form as Hole 1, of deck plate (014) partially covered by flash-band tape (013), above which sat asphalt (011), tarmac (009) and gravel ‘crust’ (008). On the pavement side, sand (012) and a cast iron curb (010) were present. 4.3 HOLE 3 Hole 3 followed a similar form to Hole 1, however without any flash-band tape or bedding sand evident. This hole was subsequently enlarged in order to identify the method used to join the deck plates and estimate the degree of corrosion suffered by them. The enlarged hole exposed deck plates (027) and (028), each of which had on the west side a cast iron bolt set into it, (033) and (034) both partially exposed. The plates had a uniform gap running between them east to west of approximately 15mm. Also exposed Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 13 Ironbridge Archaeology – Final Report was concrete ‘flaunching’ (036), which obscured the east end of the deck plates, inserted in the 1970’s to support the iron curb. Figure 2: Hole no. 3 Figure 3: Hole no. 4 Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 14 Ironbridge Archaeology – Final Report 4.4 HOLE 4 Hole 4 was enlarged like Hole 3, and followed the same form, with the exception that the iron bolts (037) and (038) were fully exposed where they were set in the deck plates (029) and (030). 4.5 HOLE 5 Hole 5 was again an enlarged hole exposing the junction between two deck plates. The two deck plates (031) and (032) had a raised flange which is covered by a strip of flash-band tape. The flanges were secured together by a bolt (041). No concrete was exposed in this excavation. Figure 4: Hole no. 5 4.6 HOLE 6 Hole 6 exposed a different form of deck plate at its base. Deck plate (025) sits above side arch S1 or S2 and has a raised flange which is covered by a strip of flash-band tape (026). The deck plate is 19th century. Sitting above the deck plate is a layer of ash and clinker (024), above which is an asphalt layer (023) both dating from the 20th century. Covering this is a thin gravel ‘crust’ (022) from the 21st century. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 15 Ironbridge Archaeology – Final Report 4.7 HOLE 7 Hole 7 exposed early 19th century deck plates (047) and (048) each of which had a 3” wide flange where they met and were held together by an iron bolt (049). The tops of the flanges were coated in bitumen (048), with flash-band tape (050) over the top which was coated in another layer of the bitumen (048). Asphalt (045) sat above the deck plates and was covered with a gravel ‘crust’ (044). 4.8 HOLE 8 Hole 8 followed the same form as Hole 7. The flanges of the deck plates (053) and (054), were covered with bitumen (056) and flash-band tape (055). Asphalt (052) and a gravel ‘crust’ (057) sat above the deck plates. The deck plates sat above the 2nd secondary arch and were early 19th century in date. Figure 5: Bolt (063) from Hole A on outer side of bridge 4.9 HOLE A Hole A exposed an upright cast iron post (060) which formed a main upright of the railings, and sat between two cast iron fascia deck plates (061) and Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 16 Ironbridge Archaeology – Final Report (062). The post was held in place by a bolt (063) which passed through it and fascia plate (062). The join between the two plates was covered by flash-band tape (064). To the side of the plates was asphalt (059) covered by a gravel ‘crust’ (058) forming the road surface of the bridge. 4.10 HOLE B Hole B followed the same form as Hole A, with an upright post (065) sitting between fascia plates (066) and (067), which were connected by a bolt (070) the head of which had eroded away. No flash-band tape was present. Asphalt (068) and a gravel ‘crust’ (069) formed the road surface of the bridge. Figure 6: Bolt (070) from Hole B on outer side of bridge 4.11 HOLE C Hole C followed the same form as Hole A, with an upright post (071) sitting between fascia plates (072) and (073), which were connected by a bolt (074) with a segmental (half moon) shaped head and a hexagonal nut (075) on the outside of the bridge. No flash-band tape was present. Asphalt and a gravel ‘crust’ formed the road surface of the bridge. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 17 Ironbridge Archaeology – Final Report Figure 7: Hole C, iron post (071) sitting between two fascia plates (072) & (073) 4.12 HOLE D Hole D followed a similar form as Hole A, with an upright post (076) sitting between fascia plates (077) and (078), which were probably connected by a rivet. No rivet or bolt remnant was observed due to a coating of bitumen (079) covering the area in which it would have sat. Asphalt and a gravel ‘crust’ formed the road surface of the bridge. 4.13 HOLE E Hole E followed the same form as Hole D, with an upright post (080) sitting between fascia plates (081) and (082), no rivet or bolt remnant was observed due to a coating of bitumen (083) covering the face of the fascia plates. Asphalt and a gravel ‘crust’ formed the road surface of the bridge. 4.14 HOLE F Hole F followed the same form as Hole C, with an upright post (084) sitting between fascia plates (085) and (086), which were connected by a bolt (087) with a segmental (half moon) shaped head and a square nut (087) on the outside of the bridge. Flash-band tape (088) covered the join of the Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 18 Ironbridge Archaeology – Final Report plates beneath the bolt. Asphalt (089) and a gravel ‘crust’ (090) formed the road surface of the bridge. Figure 8: Hole F, iron post (084) sitting between two fascia plates (085) & (086) 4.15 HOLE G Hole G followed the same form as Hole C, with an upright post (091) sitting between fascia plates (092) and (093), which were connected by a bolt (095) with a square head which also held a square ‘washer’ or plate (094) against the fascia plates, and a hexagonal nut (096) on the outside of the bridge. Bolt, washer/plate and nut were probably 19th or 20th century replacements. Flash-band tape covered the join of the plates beneath the bolt. Asphalt and a gravel ‘crust’ formed the road surface of the bridge. 4.16 HOLE H Hole H followed the same form as Hole G, with an upright post (099) sitting between fascia plates (100) and (101). These were connected by a bolt (103) with a square head and screw thread shaft which held a square ‘washer’ or plate (102) against the fascia plates, and a hexagonal nut (104) on the outside of the bridge. Bolt, washer/plate and nut were probably 19th or 20th century replacements. Flash-band tape covered the join of the plates Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 19 Ironbridge Archaeology – Final Report beneath the bolt. Asphalt (105) and a gravel ‘crust’ (106) formed the road surface of the bridge. 4.17 HOLE I Hole I followed the same form as Hole G, with an upright post sitting between fascia plates. These were connected by a bolt with a square head and a screw threaded shaft which held a square ‘washer’ or plate against the fascia plates, and a hexagonal nut on the outside of the bridge. Bolt, washer/plate and nut were probably 19th or 20th century replacements. Asphalt and a gravel ‘crust’ formed the road surface of the bridge. 4.18 HOLE J Hole J followed the same form as Hole G, with an upright post sitting between fascia plates. These were connected by a bolt with a square head and a screw threaded shaft with a square ‘washer’ or plate against the fascia plates, and a hexagonal nut on the outside of the bridge. Bolt, washer and nut were probably 19th or 20th century replacements. Asphalt and a gravel ‘crust’ formed the road surface of the bridge. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 20 Ironbridge Archaeology – Final Report 5 CONCLUSION Holes 1 - 8 Holes 1 to 4 excavated into the road deck level of the main arch exposed flat deck plates with no flange which were thought to be butted together. However, a small gap 1 – 1.5cm was seen between the deck plates. The irregular nature of sand casting may account for this gap. Rectangular bolt heads were seen to extend through the deck plates in Holes 3 and 4. These are thought to be associated with the deck end repairs of 1902. The bolts were tightened with hexagonal nuts (IGMT 1972.13). Holes 5 to 8 all had upright flanges along the edges which were then butted together. The upright flanges in Holes 5 and 7 were bolted together, suggesting that this fixing was prevalent across all those deck-plates on the side arches. Percolation of water presumably through the road deck material collected along the inner face of the flange. No exit route for this water could be ascertained from the excavation. The obvious differences in formation between the deck plates in Holes 1-4 located above the main arch and those in 5-8 located on both the side arches are a consequence of the later construction date of the side arches. These were constructed in the summer of 1821, forty-two years after the construction of the main span of the Iron Bridge. All the deck plates’ uncovered and sub-surface fixings of the upright posts had been coated with a silver flash-band tape and a painted on layer of bitumen. This was thought to be associated with earlier excavations of the road deck in the 1972 (Ironbridge Institute, 2000). Holes A to J The findings from the excavation and inspection of the sub-surface fixings of the upright posts suggest a number of phases and type of fixings are present on the bridge. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 21 Ironbridge Archaeology – Final Report Holes A and B were located above the side arch. No fixing was seen in hole B due to the fixings failure and presumably its removal during the road deck replacement works in 1975 (see Fig 6). In Hole A the fixing comprised a square headed bolt with hexagonal nut and washer on the external elevation (see Fig 5). It is possible that this formation is original to the 1821 construction of the railings. The remainder of the holes C to J were all excavated above the main arch, however a variety of fixing types were uncovered. It is thought from the formation and technology of these fixings that Hole C and F retained the earliest form of fixing as a semi-circular rounded headed bolt with hexagonal or square nut on the exterior. The fixings on holes D and E had failed, thus there was no evidence to distinguish the fixings formation. Holes G, H, I, and J all displayed a square headed screw thread bolts, fixed to a small plate. The exterior fixing was a hexagonal nut with a circular washer. These fixings are thought to be later replacements; however, they must either predate or date from the 1972 road deck replacement, as each was covered in the flash band tape and bitumen. There seems little consistency in the fixings on the upright posts, suggesting that any replacements which have been undertaken were fairly piecemeal. The evidence also suggests these fixings are prone to failure as they provide the main anchor point for the railings when under pressure. To ascertain the exact sequence of post fittings, it is recommended that further excavation or research be undertaken as to the type and condition of the other post fittings on the bridge, thereby informing the policy for management and upkeep of the structure. Road Deck In relation to the stratigraphic sequence of the road deck level, it can be said that there are no remains of the original covering for the road deck on either the main arch or the secondary side arches. This was excavated in 1972. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 22 Ironbridge Archaeology – Final Report However some coke, cinder, and ash were evident, whether this was residual or in addition to the new 1970s covering of asphalt could not be ascertained from the small excavations. Prior to the 1970s asphalting of the road level, all the joints between the deck plates were sealed with flash band tape and painted with asphalt, presumably acting as a water repellent sealant. The curbs originally laid down in 1923 were replaced (or reinstated) in the 1970s, thus the concrete and sand flaunching supporting the curbs overlaid the first layer of asphalt, after which another layer of asphalt was laid down. This was finally covered with the gravel ‘crust’ laid down under instruction from English Heritage in 2000. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 23 Ironbridge Archaeology – Final Report 6 BIBLIOGRAPHY IGMTAU, 2001, The Iron Bridge – Historical Building Survey, Record and Analysis 1999-2000, Ironbridge Archaeology, IAS 100. Ironbridge Institute, 2000, The Iron Bridge – Historical Building Survey, Record and Analysis. Trinder, Barry, 1981, The Industrial Revolution in Shropshire, Phililmore & Co. Ltd. London and Chicester. Ironbridge Archaeology – Archaeological Monitoring on the Iron Bridge January 2007 24