Grassington Moor

NAA

SURVEY AND EXCAVATION REPORT

Northern Archaeological Associates Ltd

Marwood House Harmire Enterprise Park Barnard Castle

Co. Durham DL12 8BN t: 01833 690800 f: 01833 690801 e: [email protected] w: www.naa.gb.com

GRASSINGTON MOOR

on behalf of

Project No.: 10 14 Yorkshire Dales National Park Authority Text: Paul G Johnson and Stuart Ross Illustrations: Giles McFarland and Dawn Knowles Edited by: Richard Fraser Approved by: Tania Simpson

NAA 13/71 May 2013

NAA Document Authorisation

Project name Grassington Structures Project number

Report title Grassington Moor, Survey and Excavation Report 1014

Report No . 13/71 Version Date Filename NAA_1014_Rpt_13-71_SBR.pdf v.1 20.05.13 Description Survey and Excavation

Prepared by Edited by Approved by Name Paul G Johnson Richard Fraser Tania Simpson

This document has been approved for release by: ..…… ………………….……….

GRASSINGTON MOOR

SURVEY AND EXCAVATION REPORT

Summary 1

1.0 Introduction 1

2.0 Location, topography and geology 1

3.0 Archaeological background 2

4.0 Aims and objectives 3

5.0 Methodology 3

6.0 Results 4

7.0 Discussion 21

8.0 Site archive 23

9.0 Conclusion and recommendations 23

References 24

SURVEY AND EXCAVATION REPORT

Summary

Northern Archaeological Associates Ltd (NAA) were commissioned by The Yorkshire Dales National Park Authority (YDNPA) to undertake a programme of historic building survey, and other investigative archaeological works, on structures associated with the lead mining complex at Grassington Moor, North Yorkshire (centred on SE 670 025). A large proportion of this site is a Scheduled Monument (SM 31331). The archaeological works were undertaken in advance of emergency repairs to some of the structures within the complex, and a watching brief was maintained during consolidation works to a raised causeway over rod tunnels linking Coalgrove Head Mine with the High Winding House water-wheel. The fieldwork for the project was undertaken at various times in May and July 2011, and during June and July 2012.

The objectives of the project were primarily to provide a pre-intervention record of those parts of the monument which had not previously been surveyed or which had only been surveyed in plan. These included the bridge over Coalgrove Beck and the raised causeway. However, intrusive archaeological works were also undertaken on two sections of collapsed flue leading from the smelt mill to the chimney; a former maintenance access point in the same flue and a blocked section of flue adjacent to the base of the chimney itself. These works were also undertaken to provide a pre-intervention record of the structures in advance of consolidation works, and to recover any stratified artefactual material which may assist in the dating of the construction and use of the flue.

A watching brief was also maintained during the controlled clearance of the retaining walls of the raised causeway. It was undertaken to determine the nature and condition of two rod tunnels and provide information on the detail of the construction of the causeway itself.

It is considered that this archaeological programme has provided a full record, so far as was practicable, of the structures in question prior to the emergency works. The site archive, comprising all of the drawn, photographic and descriptive records of the works undertaken during the course of the project will be deposited with the Yorkshire Dales Museum in Hawes.

Grassington Moor: Survey and Excavation Report

1.0 INTRODUCTION

1.1 Northern Archaeological Associates Ltd (NAA) were commissioned by The Yorkshire Dales National Park Authority (YDNPA) to undertake a programme of historic building survey, and other minor archaeological works on structures associated with the lead mining complex at Grassington Moor, North Yorkshire, a large proportion of which is a Scheduled Monument (SM 31331, centred on SE 670 025). The works were undertaken in advance of emergency repair works, in accordance with a specification supplied by the YDNPA (White 2011), and a methods statement prepared by NAA (NAA 2011).

1.2 The structures examined during the course of this study comprised several elements of the flue leading from the remains of the cupola mill to the chimney; the causeway bridging two rod tunnels connecting former machinery at Coalgrove Head Mine with the High Winding House water-wheel; and parts of the bridge carrying the Duke of Devonshire’s New Road across Coalgrove Beck near the cupola mill.

1.3 The report describes the locations of the works and their environs, and the methodology used in undertaking the survey and other archaeological works. The historic background and the development of the site have been summarised elsewhere (Gill 1993, LUAU 1993 and Ainsworth and Burn 2009) and it is considered that further repetition of those studies is not required here.

1.4 The fieldwork was undertaken at various times in May and July 2011, and during June and July 2012.

2.0 LOCATION, TOPOGRAPHY AND GEOLOGY

2.1 Grassington is located in Upper Wharfedale and is situated on the north bank of the River Wharfe (Figure 1). The uplands to the north-east of the town reach elevations of c. 550m OD and the of the current works were undertaken in an area formerly known as the Out Moor which comprises some 800 ha of common enclosed by the Moor Wall (Gill 1993, 8). The Out Moor presently consists of rough pasture, heath and substantial areas of former lead mining remains, and is predominantly used for grazing, shooting and other recreational purposes.

2.2 The solid geology of the Grassington area comprises Namurian Millstone Grits and Tournasian and Visean Limestones of the Carboniferous period (IGS 1977). The bedrock to the east of the river comprises millstone grits (Grassington Grit) overlying rock formations of the Yoredale series. It was from the lower levels of the Grassington Grits, the Bottom or Bearing Grit, that the majority of the lead ore mined at Grassington was won (Gill 1993, 11). The drift geology of the area, where present, comprises a mixture of boulder clay and morainic drift, peat, and glacial sands and gravels (IGS 1979). The soils of Grassington Moor largely consist of the raw oligo-fibrous peat soils of the Winter Hill association,

©Northern Archaeological Associates Ltd on behalf of YDNPA 1 Grassington Moor: Post-Excavation Report

and the strongly gleyed soils of the Wilcocks 1 association (SSEW 1980, Jarvis et al 1983, 312 and 307).

3.0 ARCHAEOLOGICAL BACKGROUND

3.1 Grassington has been a privately owned liberty from the Norman Conquest onwards. The Manor of Grassington was originally part of the Percy Fee, later sold to the De Plumpton family who, in turn, sold half to the 2nd Earl of Cumberland, and half to his brother. The halves were reunited, through marriage, by George Clifford, the 3rd Earl of Cumberland.

3.2 However, the first record of a connection between lead mining and Grassington dates to 1456 (King et al nd 19) when the monks of Fountains Abbey seem to have been working a smelt mill in the area (Morrison 1998, 118). The connection may be circumstantial, and a combination of two factors. The record is actually that of an individual from Grassington selling lead ore to Fountains Abbey, and there is place-name evidence (one Bayle Hill at Yarnbury, and another Bale Hill in the Hebden Liberty which was considered to be part of Grassington until the 18th century) to suggest the former presence of wind- blown furnaces, or ‘bales’, in the area (Gill 1993, 12). If true, lead production in this period may have been a small-scale enterprise, undertaken to satisfy local needs, and up until about 1607 the veins of Lea Green pastures were only worked by about six to eight families (Spence 1992, 168).

3.3 By the early 1600s, the Earls of Cumberland, particularly Earl George Clifford and his brother Francis, the 4th earl, began the systematic exploitation of the mineral resources on the family estates, including Grassington (ibid 157, 168). A new smelt mill, the Low Mill, had been constructed by 1606 on the River Wharfe, and by 1607 miners from Derbyshire arrived in the area, attracted by the accompanying increase in production of ore (ibid 170). By the 1630s the mines of Grassington were well established and well regulated, and profitable. A second smelt mill was subsequently constructed, the High Mill, which was located beside Coalgrove Beck on the High Moor. This is first mentioned in 1637 ( ibid 174), and its construction appears to have been the result of a need for continuity of production were the Low Mill to require maintenance, or repair as a result of the flooding of the River Wharfe.

3.4 A collapse in the profits of the lead industry occurred in the early 1650s, partly as a result of the English Civil War in the preceding decade, but mainly because of a two year stoppage in production resulting from the miners’ objections to an increase in the price of timber for use in the mines, and a levy which amounted to one-third of all of the smelted lead placed upon them. The profitability of the enterprise was largely restored by the late 1650s due to further investment, and a change in the way the miners were regulated ( ibid 181) under the ownership of the Earl of Burlington (King et al nd 20).

3.5 Ownership of the interests in the Grassington industry changed again in the later decades of the 18th century when lead mining and processing in the area

©Northern Archaeological Associates Ltd on behalf of YDNPA 2 Grassington Moor: Post-Excavation Report

became linked with the Dukes of Devonshire. The mines had become nearly exhausted by the 1790s, and this prompted the Devonshires to invest considerable sums into the industry. The principal improvements included the excavation of the Duke’s Level, which facilitated drainage in the mines and allowed deeper shafts to be sunk; the provision of a complex series of dams and watercourses required to supply a (final) total of eight water-wheels; the construction of a cupola mill and its attendant system of flues in about 1793 (but modified and improved into the mid 19th century) and the improvement of the surface communications network through the construction of the Duke’s New Road in 1830 (Morrison 1998, 119-121). The repair and maintenance of elements of the latter two comprised the basis of this project.

3.6 Lead mining ceased on Grassington Moor in about 1882 although there were a number of campaigns of spoil reprocessing undertaken in the 20th century. These works were primarily concerned with the extraction of barytes and fluorspar, but these enterprises ended in the late 1970s (Gill 1993 136-141).

4.0 AIMS AND OBJECTIVES

4.1 One of the principal objectives of the archaeological works was to provide a pre-intervention record of those parts of the monument which had not previously been surveyed or which had only been surveyed in plan, in advance of emergency consolidation works. These included the bridge over Coalgrove Beck and the raised causeway over the rod tunnels linking Coalgrove Head mine with the Brake House water-wheel.

4.2 Intrusive archaeological works were undertaken on two sections of collapsed flue leading from the smelt mill to the chimney, a former maintenance access point in the same flue and a blocked section of flue adjacent to the base of the chimney. The principal aim of this work was to make a pre-intervention record of these structures in advance of any consolidation works occurring, and to recover any stratified artefactual material which may assist in the dating of the construction and use of the flue. These works were only undertaken in areas which involved the removal of soil deposits covering the structures requiring consolidation.

4.3 A watching brief was also maintained during controlled clearance of the retaining walls of the raised causeway. It was undertaken during consolidation works to determine the nature and condition of two rod tunnels and provide information on the detail of the construction of the causeway itself.

5.0 METHODOLOGY

5.1 A control framework for the survey was established through a network of control stations established using a Leica TCR 705 Total Station Theodolite (TST). The control network was created to allow the building survey and the locations of other works to be accurately located within the Ordnance Survey

©Northern Archaeological Associates Ltd on behalf of YDNPA 3 Grassington Moor: Post-Excavation Report

National Grid. All of the elevations of the bridge were surveyed with the TST, the causeway being recorded by hand as a consequence of its long, low elevations.

5.2 A photographic record was made of all the structures using black and white monochrome print film at 35mm, and a digital camera at a resolution of 14 megapixels. All elevation photographs were taken from vantage points as near parallel as possible to the structure being recorded. The record included general views of each structure within its context, as well as detailed shots of significant elements. Each photograph contained a graduated photographic scale of appropriate dimensions as well as a north arrow where appropriate. The photographs of the bridge elevations contained non-reflective targets for use in subsequent image processing, each target being located in three- dimensions with the TST. The images were processed using Corel Photo Paint 12 to make minor adjustments to clarity and to make them suitable for use in AutoCAD. The images were then superimposed upon the surveyed framework of the relevant elevation. Each image was then individually rectified onto the survey base using AutoCAD Map with Raster Design. The composite image was then digitised to create the elevations presented in this report.

5.3 The positions of all of the excavation trenches were recorded using the TST in relation to the local control network, their positions later being corrected to the Ordnance Survey National Grid (Figure 2).

6.0 RESULTS

Area 1

6.1 Area 1 was located across the southern part of the main south-west to north- east aligned flue and was situated some 50m to the north-east of the smelt mill (Figure 2). Archaeological work undertaken here included the excavation of a trench to expose the top and side of the flue structure ahead of the consolidation of a dilapidated section.

6.2 Topsoil was removed from the flue which exposed a void within the structure and resulted in a further collapse of the voussoirs and part of the side wall. To avoid compromising its integrity further, excavation works were ceased within the immediate vicinity of the collapse. The trench was then extended to the south-east to examine the form and fabric of the flue away from the collapsed area.

6.3 The trench was ‘L’-shaped and covered an area 2.6m x 1.3m in size (Figure 3). It was excavated to a maximum depth of 0.65m which was recorded immediately adjacent to the flue. Excavations exposed the south-east facing side of the flue vault and the overlying deposits (Plates 1, 2 and 3).

©Northern Archaeological Associates Ltd on behalf of YDNPA 4 Grassington Moor: Post-Excavation Report

Plate 1: Area 1 Plate 2: Area 1, flue vault 8

6.4 The earliest feature exposed was the flue vault (8). The vault was constructed using roughly shaped angular sandstone slabs up to 0.25m x 0.1m in size. The stones had been wedged in place and some smaller fragments had been packed between the larger slabs to maintain the profile of the arch. The larger stone slabs were overlapped along the length of the structure in an irregular manner. Lime mortar was identified in places although its use appeared to have been restricted to blocking voids within the masonry rather than as a bonding material. The extrados of the flue vault was poorly finished and it seemed that the entire structure was designed to be covered by an earthen bank to provide both structural integrity and to seal gases within the flue.

6.5 The flue was overlain by a deposit of mid-brown sandy silt (10) which contained a large quantity of small sandstone fragments that appeared to be stone working debris from production of the main sandstone components of the flue. This deposit was identified banked up against the south-east side of the flue and was severely degraded and discoloured to dark orange silty sand (9) within the immediate vicinity of the masonry. It seemed likely this was due to the extreme temperatures that must have Plate 3: Area 1, flue vault 8 been generated by the gases passing through the flue.

©Northern Archaeological Associates Ltd on behalf of YDNPA 5 Grassington Moor: Post-Excavation Report

6.6 The apex of the vault (8), and bank material 10 were overlain by mid-yellow brown sandy silt (11). The nature of this deposit, which differed from that of the bank material (10), may simply have reflected the soil types available for the sealing of the flue following its construction. However it is possible that this material may have represented backfill material deposited following a repair to the structure within the vicinity of the current dilapidation. The entire structure was then sealed by topsoil 12 which was formed almost entirely of grass roots.

Area 2

6.7 Area 2 was located c.5m to the north-east of Area 1 and was programmed as an area of further excavation over another dilapidation of the flue. No work was undertaken here due to the unstable nature of the underlying flue and additional collapses caused by the removal of the topsoil within Area 1.

Area 3

6.8 Area 3 was located approximately 350m to the north-east of the smelt mill and about 175m to the south-west of the chimney (Figure 2). Archaeological work undertaken within this area comprised the excavation of two trenches to investigate the form and function of a flue access hatch situated within the northern side of the flue and adjacent to the site of a former condenser house. The trench was rectangular and measured 1.3m x 1.2m. It was excavated to a maximum depth of 0.9m. A smaller trench (Trench 3B) was excavated 0.7m to the west in an attempt to identify any continuation of the access point towards the condenser house (Figure 3).

Plate 4: Area 3, flue access aperture

©Northern Archaeological Associates Ltd on behalf of YDNPA 6 Grassington Moor: Post-Excavation Report

6.9 The flue access hatch (3) was constructed using roughly squared sandstone blocks with maximum dimensions of 0.5m x 0.15m (Plate 4). The masonry had an irregular coursing and appeared to be laid without the use of mortar. The feature originally comprised two wing walls, of which only the western example survived in its entirety, which presumably flanked a ramped entrance (as visible elsewhere on site). The walls were spaced c.1m apart at the western end of the trench and away from the flue entrance and narrowed to 0.45m at the point of entry. The wing walls were crudely keyed into the flue structure indicating they were contemporary features (Plate 5). No continuation of the western wing wall was identified within the additional Trench 3B. The point of entry was built into the side wall of the flue and was contemporary with its construction. It was rectangular measuring c.0.45m x c.0.6m and was surmounted by a stone lintel. The hatch comprised a rectangular slab of stone that rested against stone blocks which projected from the jamb on the internal side of the flue (one lower, one upper block to either side). The slab appeared to be a tight fit within the jamb and was seemingly designed to fall away from the flue to facilitate access. The method of retaining the slab in the closed position was not identified. A further stone lintel, which had collapsed slightly at its northern end, was located above the entrance and was supported by the wing walls.

Plate 5: Area 3, western wing wall

6.10 The structure of both the flue and access hatch had material banked over and to the sides of them. In this case the re-deposited material comprised mid- yellow brown clay (4) with few stone inclusions.

©Northern Archaeological Associates Ltd on behalf of YDNPA 7 Grassington Moor: Post-Excavation Report

6.11 The access hatch was filled by dark brown sandy silt deposit (7) which contained numerous squared sandstone blocks possibly representing the collapsed northern wing wall. These masonry fragments had average dimensions of 0.3m x 0.2m x 0.15m and included a fragment of brick. All deposits were sealed by topsoil 5.

Area 4

6.12 Area 4 was located at the base of the chimney situated at the north-eastern end of the flue (Figures 2 and 4, Plate 6). The archaeological works undertaken here comprised the production of a pre-intervention record of a section of collapsed flue (13). This included a written, drawn and photographic record. The uppermost courses of the vault of the flue was missing for a length of approximately 2m in this section though whether this was a result of a collapse in the past, or the result of a partial dismantling of the flue at the base of the chimney in order to facilitate past remedial or other works was unclear (Plates 6 and 7). The presence of a single, flat, slab at the end of the flue, immediately adjacent to a blocked aperture into the chimney would seem to support the latter interpretation. The uppermost courses of the surviving flue contained evidence of past consolidation work in the form of cement pointing, this now being in poor condition.

Plate 6: Area 4, collapsed flue 13

©Northern Archaeological Associates Ltd on behalf of YDNPA 8 Grassington Moor: Post-Excavation Report

Plate 7: Area 4, collapsed flue 13 Plate 8: Area 4, collapsed flue 13

Area 5

6.13 Area 5 was located on a raised causeway over rod tunnels linking Coalgrove Head Mine with the High Winding House water-wheel approximately 400m to the north-east of the chimney (Plate 9; Figures 2, and 5). The tunnels once accommodated winding ropes and pump-rods which were carried in excess of 350m across the moor in the tunnels (Raistrick 1953, 185). The tunnels, or pump-rod tracks, may have served a secondary function (Raistrick 1926, 88) in supplying water pumped from the mine to the reservoir adjacent to the water- wheel, or perhaps directly to the wheel itself. The archaeological works undertaken here included a pre-intervention record of the causeway retaining walls (Plates 9 and 10) prior to limited investigation of the detail of the rod tunnel entrances and causeway during removal of collapsed elements of the wall ahead of consolidation works.

6.14 The causeway was constructed from sandstone rubble in a soil matrix surfaced by crushed stone, which was probably reused mining waste, that partially sealed, and obscured, lintels which capped the underlying rod tunnels. The retaining walls were of dry-stone coursed sandstone rubble capped by a kerb of roughly dressed boulders which had suffered significant collapses in the vicinity of the tunnels entrances on the southern side of the structure (Plate 11). Substantial parts of the structure had also slumped over time, resulting in the spreading of some of the track make-up material onto the land-surfaces on either side.

©Northern Archaeological Associates Ltd on behalf of YDNPA 9 Grassington Moor: Post-Excavation Report

Plate 9: Area 5, northern causeway retaining wall

Plate 10: Area 5, southern causeway retaining wall

©Northern Archaeological Associates Ltd on behalf of YDNPA 10 Grassington Moor: Post-Excavation Report

Plate 11: Area 5, western end of southern causeway retaining wall

6.15 The two rod tunnels were located parallel to one another and were aligned south-west to north-east with a total length of c. 4m beneath the overlying causeway. Internally, the tunnels were 0.7m wide and had a depth greater than 0.45m, although the bases were not exposed during investigations (Plate 12). The tunnel sidewalls generally survived in very poor condition and were constructed from dry-stone coursed sandstone rubble fragments of varying sizes. The masonry forming the corner between the tunnel sidewalls and the outer retaining wall had been dressed to 45 degrees reflecting the angle at which the causeway bridged the rod tunnels. Both tunnels were capped by rows of sandstone lintels, most of which were Plate 12: Area 5, north-eastern rod broken, displaced or collapsed. tunnel entrance following excavation

©Northern Archaeological Associates Ltd on behalf of YDNPA 11 Grassington Moor: Post-Excavation Report

6.16 Excavations did not penetrate deep enough to fully determine if the tunnels also functioned as water channels, however the lowest deposit identified within the north-eastern tunnel entrance comprised light grey well sorted course sand that may have been deposited by flowing water. A water-filled depression was located adjacent to the north-western rod tunnel entrance which continued the alignment of the rod tunnel to the north-east and may have represented the weathered remains of a water channel (Plate 13).

Plate 13: Area 5, north-western rod tunnel (marked by 1m scale and water filled depression)

Area 6

6.17 The bridge over Coalgrove Beck is situated just to the north of the cupola mill, and now carries part of the Duke of Devonshire’s New Road across Coalgrove Beck (Figure 2). The bridge incorporates an earlier structure, the vault of the bridge clearly showing that it was widened towards the north, and underwent a slight change of alignment at the same time (Plate 14). It is tempting to consider that these alterations occurred in 1830 when the new road was constructed, and that the earlier version of the bridge serviced the cupola mill which was built in about 1793.

©Northern Archaeological Associates Ltd on behalf of YDNPA 12 Grassington Moor: Post-Excavation Report

Plate 14: Area 6, bridge vault

6.18 The northern side of the bridge was fully recorded; the southern side which was in an extremely poor state of repair having suffered a series of collapses and ad hoc repairs was recorded but not drawn.

Northern side

South-west facing elevation (Wall 1, Figure 6)

Plate 15: Area 6, Wall 1

©Northern Archaeological Associates Ltd on behalf of YDNPA 13 Grassington Moor: Post-Excavation Report

6.19 The south-west facing elevation of the bridge structure survived to a maximum height of 2.6m and was a maximum 5m long (Plate 15). The wall was constructed from dry-stone, coursed rubble, the individual sandstone blocks of which were graded in size, the largest being situated at the bottom of the wall. The structure was slightly battered, and contained no string courses. The wall had partially collapsed at the north-western end, and the top few courses of the wall at its south-eastern limits had also collapsed. The opening for a culvert, 1.3m high and 0.8m wide occupied the lower part of the south-eastern end of the wall (Plate 16). This was surmounted by a single sandstone lintel, 1.1m long with a maximum thickness of 0.25m. The masonry of the south- eastern end of the structure was keyed into the fabric of the north-west facing elevation.

Plate 16: Area 6, culvert opening in Wall 1

North-west facing elevation (Wall 2, Figure 6)

6.20 The north-west facing elevation survives to maximum height of 3.0m at its southern end, and was 7.0m long between Wall 1 and the arch of the bridge vault (Wall 3, Plate 17). This wall was constructed of dry-stone coursed sandstone rubble masonry and was stepped twice, rather than battered towards the top, the offsets corresponding with the top and the bottom of the culvert aperture to the north-east. The uppermost courses of the wall at its southern end had fallen. The individual blocks of the wall were not so obviously graded as those comprising Wall 1, although the bottom courses of this structure were predominantly built from larger stones. The masonry above this level comprised a mixture of large and smaller stones with larger blocks being

©Northern Archaeological Associates Ltd on behalf of YDNPA 14 Grassington Moor: Post-Excavation Report

present to the full height of the wall at its centre. Copious use had been made of small, thin, wedges of stone to level up the individual blocks of the fabric of the structure. The masonry of this wall continued into the culvert to the north- east, and beneath the vault of the bridge to the south-west.

Plate 17: Area 6, Wall 2

North-east facing elevation (Wall 3, Figure 7)

6.21 The north-east facing elevation of the bridge survives to a maximum height of just over 3.0m above the bed of the beck and was 2.5m long at the top, narrowing to 1.5m at its base, where it was partially obscured by the masonry of Walls 2 and 4 which run perpendicularly (Plate 18). The wall comprised the upstream portal arch of the bridge crossing Coalgrove Beck, and the masonry above the arch, all of dry-stone construction. The arch was sprung directly from the wall of the bridge tunnel, which was itself a continuation of Wall 2, the point of intersection of the arch with the wall being marked only by a slight vertical step in the masonry of the wall accompanied by a slight change in orientation. The arch-head comprised a semicircular arch constructed from roughly rectangular blocks of stone of varying thicknesses, the curve of the arch being maintained by a series of triangular wedges placed between the larger blocks on the outer face of the arc. The arch was surmounted by a course thin rectangular blocks laid to follow the outer arc of the archway, but placed perpendicularly. This course was not keyed into Walls 2 and 4 but simply wedged against them. The function of this course is not clear; it may have been intended as an aesthetic effect and it clearly did not act as a relieving arch. Despite protruding slightly from the wall face, it could not really

©Northern Archaeological Associates Ltd on behalf of YDNPA 15 Grassington Moor: Post-Excavation Report

be described as a string course either. This masonry was perhaps laid to provide a more uniform, albeit curved, platform on which to construct the remainder of the elevation, and it may have continued further into the vault of the bridge in order to perform the same function. This feature was not noted in the arches of the flue system where they entered condenser structures where additional support would not have been necessary in the flues which were simply buried with soil deposits and did not have to support masonry above the vault.

Plate 18: Area 6, Wall 3

6.22 The masonry built above the vault comprised a mixture of blocks of varying sizes used to level the wall to a point equivalent to the head of the arch, thereafter it was composed of coursed rubble masonry with the larger blocks generally being incorporated into the lower courses. There was a slight outward step in the line of the wall at the interface of the levelling masonry and that above but it was unclear if this was intentional, or the result of later movement in the masonry.

6.23 The whole of the arch of the bridge, and the vault behind, seems to have canted slightly towards the north-west. The vault of the bridge is clearly the product of at least two episode of construction, and the whole bridge seems to have been widened in a north-eastwards direction at some stage (Plate 19). The profile of the vault of the bridge changes some 3-4m from the north-western portal, and the manner in which was constructed was different, the barrel of the vault being sprung from behind two near parallel walls built onto the bed of the beck, rather than from the face of the walls further to the north-west. The

©Northern Archaeological Associates Ltd on behalf of YDNPA 16 Grassington Moor: Post-Excavation Report

point of interface between the two phases of wall were clearly visible, height of the vault being slightly smaller for the bulk of the structure to the south-west. The bed of the beck below the earlier vault was neatly finished in setts that to the north east, beyond the intersection of the earlier and later vaults, was obscured by debris, but may have been unfinished bedrock (Plates 20 and 21).

Plate 19: Area 6, Wall 3

Plate 20: Area 6, bed of beck (SW) Plate 21: Area 6, bed of beck (NE)

South-east facing elevation (Wall 4, Figures 7 and 8)

6.24 The south-east facing elevation of the complex comprised a semi-ruinous fragment of dry-stone wall surviving to a maximum height of 2.5m, and less than 1.0m long. The masonry is roughly coursed, although there is no size preference of the blocks of stone used within any particular part of the wall.

©Northern Archaeological Associates Ltd on behalf of YDNPA 17 Grassington Moor: Post-Excavation Report

This wall butt-joints Wall 3 on its north-western end, and partially obscures the face of the arch of the bridge (Plate 22). At the point where the arch of Wall 3 begins to curve, there is a single outward step in Wall 4, the remainder of the masonry above only being partially keyed into Wall 3. The entire wall is slumping towards the north-east and numerous voids within the fabric of the wall are apparent. The junction between Walls 4 and 5, which would have been at the point of the return between the walls, has gone and large quantities of collapsed masonry are present in the bed of the beck at this point . Plate 22: Area 6, wall 4

North-east facing elevation (Wall 5, Figure 7)

6.25 Wall 5 is a fragment of a dry-stone wall which survives to maximum dimensions of 2.25m high and 3.5m long (Plate 23). The lower courses of the wall survive in an extremely poor state and comprise large rectangular blocks of sandstone masonry with an outward step between this and the rather better preserved masonry above. This comprises coursed rubble masonry and incorporates blocks of stone of varying dimensions, with no size-sorting apparent within the coursing. A single, large stone, which could be described as a coping stone, remains in situ at the north western end of the feature, but the wall has collapsed at both at this, and its south-eastern ends.

Plate 23: Area 6, Wall 5

©Northern Archaeological Associates Ltd on behalf of YDNPA 18 Grassington Moor: Post-Excavation Report

Southern side

6.26 The southern bridge portal is in a poor state of repair and the surviving remains represent the latest phase of what appears to be a number of episodes of repair work undertaken to a poor standard (Plate 24) The present façade comprises two sloping pillars of stonework, each originally three blocks high, which support three in situ re-used waggon-way rails acting as lintels between the pillars, with three further lengths of rail being wedged between these and the masonry of the extrados of the vault of the bridge (Plate 25). A fourth waggon- way rail, formerly acting as another lintel, has fallen and lies in the bed of the beck. The rails support a quantity of loose rubble, probably the remains of a small kerb lining the side of the trackway roadway above the bridge. There is a short length of dry-stone revetment wall situated to the south-western side of the bridge portal which abuts the pillar on this side, its counterpart to the north-eastern side having slumped away accompanied by the partial o the collapse of the pillar on the same side. As a result, the north-eastern pillar was heightened in an ad hoc manner simply by wedging further blocks of stone between the top of the pillar, and the waggon-way rails in the attempt to maintain the integrity of the structure. Further elements of dry-stone walling are evident to the north-east of the collapse, but downslope of the head of the bridge portal. This too has partially slumped and its original form is not clear (Plate 26).

Plate 24: Area 6, SW bridge portal

©Northern Archaeological Associates Ltd on behalf of YDNPA 19 Grassington Moor: Post-Excavation Report

Plate 25: Area 6, SW bridge portal, waggon-way rails reused as lintels

Plate 26: Area 6, SW portal, remains of revetment wall

6.27 That the surviving portal represents a repair is evident just upstream of the present façade. The bridge vault beyond this point comprises a semicircular

©Northern Archaeological Associates Ltd on behalf of YDNPA 20 Grassington Moor: Post-Excavation Report

barrel vault, slightly flattened at its apex (probably as a result of it beginning to fail), sprung from behind the two parallel walls noted above, therefore representing the earlier of the phases of construction identified during the course of this study. The face of the original arch of the bridge has fallen off, leaving the unfinished masonry of the vault exposed. Although this has been partially concealed behind the present façade, the two walls upon which it was built extend towards, and beyond this façade to briefly follow the line of the beck downstream. After extending for c.1.5m, the north-easternmost wall appears to terminate in two substantial sandstone quoins in a position roughly below the remnant dry-stone walling noted on this side of the bridge. The termination of the southwestern wall was not obvious and may be concealed below slumped stream bank material, or collapsed masonry.

7.0 DISCUSSION

7.1 The flue system for the smelt mill at Grassington is extensive and complex, comprising about 2km of tunnel system rising 150m between the Cupola Mill and the surviving chimney. The original flue was only about 60m in length and incorporated two condensers. This network was extended after 1830, and the complexity of the surviving system reflects the need to close down whole sections of the flue for cleaning and repair, whilst still maintaining the productive capacity of the smelt mill (Morrison 1998, 120). Large stone slabs were used at key points within the system to seal sections of the flues when gas diversion was required, or, as examined in Area 3, to permit access to sections of the flue requiring maintenance. In the former case, the slabs could be moved vertically, and appear to have been linked to some mechanism to raise and lower the slab to permit or restrict gas flow. In the latter case, large slabs seemed to simply have been propped into an inspection aperture, and removed when required for access.

7.2 The flue as examined comprised a horseshoe profile with battered side-walls and a semi-circular barrel vault (Plate 27). The intrados of the vault was reasonably well finished with the individual stones being roughly flush with one another. The extrados was unfinished and was designed to be covered beneath an earthen bank which provided integrity to the structure and prevented gases from prematurely escaping the flue. The masonry of the vault was formed without springers, as a result of its horseshoe shape, and no keystones were used. The flue was constructed using larger square cut blocks for the majority of the structure with the masonry of the barrel vault being formed by a series of thinner stone slabs, presumably erected over wooden centring. Smaller fragments of sandstone had been wedged between these on the outer face to maintain the curve of the arch. Lime mortar was also noted in places, however its use appeared to be quite selective. The flue seems to have been constructed in sections, possibly by different gangs of workmen, with each section being finished in an arched face, which was butt jointed to a counterpart face in the succeeding section.

©Northern Archaeological Associates Ltd on behalf of YDNPA 21 Grassington Moor: Post-Excavation Report

Plate 27: Smelt mill flue

7.3 The causeway was a fairly simple structure and was built solely to provide some level of protection for a pair of underlying rod tunnels. The tunnels were formed by sidewalls capped with sandstone lintels, most of which were broken, collapsed and displaced, which once contained winding ropes that provided drive for machinery at Coalgrove Head Mine. The overlying causeway was constructed from sandstone rubble surfaced by crushed stone and was retained by a crude wall to either side capped by a kerb of dressed boulders. Some evidence for the secondary use of the rod tunnels as water channels was also identified.

7.4 The bridge crossing Coalgrove Beck near the cupola mill is a curious structure, both in terms of its form and its history. The bridge has clearly been widened at some point, and its alignment may have been slightly altered at the same time. The bridge may once have been intended to service the cupola mill alone, the main access route onto the moor being along Moor Lane. The construction of the Duke’s New Road in the early 1800s provided a second, less precipitous access route onto the moor, and the remodelling of the bridge may have occurred at around the same time.

7.5 In terms of its form, the downstream portal is a relatively straightforward structure, and probably represents the remains of the original, pre-widening, portal of the bridge on its southwestern side. This is now in poor condition and has obviously been the subject of ad-hoc repair work in the past. The fact that these repairs contain waggon-way rails suggests that this was undertaken in a period when waggon-ways were redundant features, a period which may

©Northern Archaeological Associates Ltd on behalf of YDNPA 22 Grassington Moor: Post-Excavation Report

coincide with the re-processing of mining spoil for barytes and fluorspar at various times in the 20th century (Gill 1993, 136-141). The upstream side of the bridge is rather more complex, situated as it is at the confluence of Coalgrove Beck and the discharge point of a culvert running beneath what may be a spoil heap to the north east. This arrangement is only achieved in an untidy manner, the waters of the beck having to negotiate a right angle in order to flow under the bridge, those from the culvert flowing in a straight line. Wall 2 would have had to have taken the brunt of the flow of Coalgrove Beck when in spate, and the turbulence and backwash created by such events has undoubtedly contributed to the erosion, and partial collapse of walls 4 and 5.

8.0 SITE ARCHIVE

8.1 The site archive comprises all of the drawn, photographic and descriptive records of the works described above. These are currently held by NAA and will be deposited with the Yorkshire Dales Museum in Hawes upon completion of the project. No finds were recovered during the course of the fieldwork, and no palaeoenvironmental samples were taken.

9.0 CONCLUSION AND RECOMMENDATIONS

9.1 This report presents the results of a series of pre-intervention works undertaken in archaeological conditions on a number of structures relating to the former lead mining industry on Grassington Moor, prior to a programme of emergency repairs being undertaken on these structures. It is considered that this archaeological programme has provided a full record, so far as was practicable, of the structures in question prior to the emergency works.

©Northern Archaeological Associates Ltd on behalf of YDNPA 23 Grassington Moor: Post-Excavation Report

REFERENCES

Ainsworth S and Burn A, (2009) Grassington Moor Lead Mines, North Yorkshire, A rapid assessment of the threats posed by road management and erosion. English Heritage Research Department Report 41/2009

Countryside Consultants and Blackett Ord Conservation Engineering (2011) Schedule of Works and Specification for Emergency Works to the Lead Mining Structures at Scheduled Monument Number 31331 on Grassington Moor, in the Yorkshire Dales National Park. Unpublished

English Heritage (2001) Centre for Archaeology Guidelines: Archaeometallurgy.

English Heritage (2006) Management of Research Projects in the Historic Environment

Gill, M C (1993) The Grassington Mines . British Mining, 46 . Northern Mines Research Society Monograph. Keighley.

Gill, M C (1998) The Greenhow Mines . British Mining, 60 . Northern Mines Research Society Monograph. Keighley.

King, A, Spence R, Butler L, Fethney P and Ramm H (1995) Early Grassington, An Archaeological and Historical Trail Yorkshire Archaeological Society. Settle.

LUAU (1993) Grassington Moor Lead Smelting Mill, North Yorkshire: Archaeological Survey. Unpublished.

LUAU (1994) Grassington Moor Lead Smelting Mill, North Yorkshire: Additional Recording. Unpublished.

Menuge, A (2006) Understanding Historic Buildings: a guide to good recording practice. English Heritage. Swindon.

Morrison J (1998) Lead Mining in the Yorkshire Dales . Dalesman. Skipton.

Northern Archaeological Associates Ltd (2011) Grassington Moor, Grassington, North Yorkshire. Former Lead Mining Structures, Archaeological Works Project Proposal. Unpublished

Raistrick, A (1926) Notes on Lead Mining and Smelting in West Yorkshire. Proceedings of the Newcomen Society 7

Raistrick, A (1953) The Mechanisation of the Grassington Moor Mines, Yorkshire. Proceedings of the Newcomen Society 29

Spence R T (1992) Mining and Smelting in Yorkshire by the Cliffords, Earls of Cumberland, in the Tudor and early Stuart period . Yorkshire Archaeological Society 94

White, R (2011) Urgent Consoldaton Works – Grassington Moor. Specification for Archaeological Works . Unpublished

0 5km

scale 1:250,000 @ A4

468

site location 467

466

465

0 1km

Area 5 Fig.5

Area 4 Fig.4

Area 3 Fig.3 flue

Area 6 Fig.6-7 bridge Area 2 Area 1 N Fig.3

0 200m

scale 1:5000 @ A4

line of flue NW SW 147.66m

12 11

11 collapse

8 08 10 9 09

section 1

0 2m 0 1m

scale 1:50 @ A4 scale 1:20 @ A4

Area 3 Section 2 NW SE 168.32m

3B 04

04 04 03

section 2

line of flue 0 2m 0 1m

scale 1:50 @ A4 scale 1:20 @ A4

line of flue N

0 2m

scale 1:50 @ A4

Causeway plan north wall of causeway A' A

causeway rod tunnel lintels

B B' south wall of causeway

0 10m

scale 1:300 @ A4

Causeway north wall, recorded elevation (A-A')

E W 199.56m

Causeway south wall, recorded elevation (B-B')

W E 199.18m

slumping slumping slumping slumping

0 5m

scale 1:100 @ A4

© NAA 2013 Grassington Moor Area 5: plan and elevations Figure 5 Bridge and retaining walls, Grassington Moor Area 6 Grassington, Yorkshire Dales National Park, North Yorkshire Surveyed June 2011 Wall 1 OS Grid Reference 402470, 466367 course of culvert beck Wall 1

Wall 2

step bridge

step

KEY culvert vegetation NW SE 137m OD cracks and damage collapsed rubble wall cutaway

Wall 2

collapse

step

culvert NE SW 137m OD

step

collapsed rubble

arched bridge tunnel

0 2m

scale 1:50 @ A4 © NAA 2013 Grassington Moor Area 6: walls 1 and 2 Figure 6 Bridge and retaining walls, Grassington Moor Area 6 Grassington, Yorkshire Dales National Park, North Yorkshire Surveyed June 2011 OS Grid Reference 402470, 466367 course of culvert beck

Wall 5

Wall 4

Wall 3 bridge

Wall 3 Wall 4 Wall 5

bridge

coping stone

step

SE NW SW NE SE NW 137m OD 137m OD 137m OD

step step tunnel step

tunnel

KEY

cracks and damage 0 2m wall cutaway scale 1:50 @ A4