Ilmington Geophysics

ILM14: Rear of Washbrook Place, Ilmington 1

FLUXGATE GRADIOMETER SURVEY, REAR OF WASHBROOK PLACE,

ILMINGTON

Geophysical Survey Report

Site Code: ILM14

NGR: SP 2152 4352

Giles Carey with Brian Meredith

2014


Contents

Contents.......................................................................................................................................2 List of Figures ..............................................................................................................................2 Summary......................................................................................................................................3 Summary......................................................................................................................................3 Acknowledgements......................................................................................................................3 Introduction ..................................................................................................................................4 Project Background......................................................................................................................5

Site Location.............................................................................................................................5 Aims and objectives..................................................................................................................5 Archaeological background ......................................................................................................5

Geophysical survey......................................................................................................................7 Standards .................................................................................................................................7 Field methods...........................................................................................................................7 Data processing .......................................................................................................................7

Results .........................................................................................................................................8 Fieldwalking .................................................................................................................................9 Metal detected finds...................................................................................................................10 Conclusions ...............................................................................................................................11 Bibliography ...............................................................................................................................13 Appendix 1: Technical data........................................................................................................15

List of Figures

General location of Ilmington, c.11km south of Stratford-upon-Avon in the Cotswolds fringe. Image: Google Earth....................................................................................................................4 Figure 1: Survey Location ..........................................................................................................16 Figure 2: Magnetic Data Greyscale (Raw) .................................................................................17 Figure 3: Magnetic Data Greyscale (Processed) .......................................................................18 Figure 4: Interpretation Plan.......................................................................................................19 Figure 5: LiDAR DSM, showing Topographic Location of site....................................................20


Summary

A programme of fluxgate gradiometer survey was undertaken in 2014 on the summit of Windmill

Hill, to the east of Ilmington (centred on SP 2152 4352). Finds made in the area from the 1970s

onwards have indicated a possible settlement focus here, of Iron Age/Roman date. The aim of

the survey was to evaluate the extent to which these finds related to sub-surface archaeological

deposits. The opportunity was also taken to conduct a rapid fieldwalking exercise to provide a

date for any such deposits.

The results have been extremely promising. The main set of anomalies relate to a sub-

rectangular enclosure with a number of peripheral enclosures, suggested as being of Late Iron

Age date. The fieldwalking has suggested continued occupation here in the Roman period,

which was also seen in finds recently collected across this area through metal detecting.

Acknowledgements

The survey would not have been possible without the enthusiasm and hard work of Brian

Meredith, who enabled access to the site and assisted greatly during the survey, together with

Susan Brock. Brian also provided information on the fieldwalked finds and details of the metal

detector survey. Thanks are also due to Caroline Rann and Bryn Gethin for their support and

assistance with aspects of the survey. Permission to carry out survey was granted by the

landowner, Mr Rob Hawkins.

Background archaeological information was obtained from Warwickshire HER, with additional

information via Brian Meredith. I would also like to thank John Robinson, Warwickshire HER

and Stuart Palmer, Archaeology Warwickshire for discussion of the background material.

The geophysical survey would not have been possible without equipment loaned by English

Heritage; access was kindly arranged through the good offices of Andy Payne. Warwickshire

County Council (Archaeological Information and Advice) loaned the laptop and processing

software.

All conclusions/interpretations are the author’s responsibility alone.


Introduction

This report presents the results of a small scale fluxgate gradiometer survey carried out atop

Windmill Hill, to the East of Ilmington (centred on SP 2152 4352). Finds made in the area from

the 1970s onwards have indicated a possible settlement focus here, of Iron Age/Roman date.

The aim of the geophysical survey was to evaluate the extent to which these finds related to

sub-surface archaeological deposits. The opportunity was also taken to conduct a rapid

fieldwalking exercise to provide a date for any such deposits.

GENERAL LOCATION OF ILMINGTON,

C.11KM SOUTH OF STRATFORD-UPON-AVON IN THE COTSWOLDS FRINGE. IMAGE: GOOGLE EARTH


Project Background

Site Location

The survey area was an area of pasture on the summit of Windmill Hill, a glacial mound to the

east of Ilmington. The hill rises to c.180m OD. Ground conditions were generally good during

the survey. The survey was undertaken on three separate occasions throughout 2014, during

January, July and October but the weather was largely dry and fairly bright throughout the

survey.

Aims and objectives

The purpose of any geophysical survey is to “as far as reasonably possible, determine the

nature of the detectable archaeological resource within a specified area using appropriate

methods and practices” (English Heritage, 2008: 3).

The key aim of the survey was to assess the site for the survival of subsurface archaeological

remains which might respond to magnetic survey. In addition, through systematic field survey it

was hoped to provide an updated appraisal of the date of any occupation in this area, furthering

understanding of the material originally collected from this area in the 1970s.

Archaeological background

Ilmington is located within the parish of the same name, c. 11km south of Stratford-upon-Avon,

in the Cotswolds fringe. Ilmington is thought to be early medieval in origin and is recorded as a

pre-Conquest manor in Domesday, being mentioned 3 times (HER MWA8943). The place-

name is recorded as ‘Edelmitone’ in 1086 and ‘Ylmandune’ in c. AD 1000 (AOC Archaeology,

2012: 114). The name is thought to derive from the Old English ‘ulm’ (elm) and ‘dun’ (hill)

(Gower et al., 1970), possibly meaning ‘elm-tree hill’ (Key to English Place Names, 2014). First

and second edition Ordnance Survey mapping shows a nucleated settlement pattern in the 19th

century, focused around the church in the southwest of the settlement. Extensive ridge and

furrow has been recorded around the village (HER MWA6446). Subsequent 20th century

development is limited to areas along the eastern and southern fringes of the village.

The survey area, atop Windmill Hill, to the east of the village itself, is a suggested focus of Iron

Age and Roman settlement. A collection of pottery of largely Romano-British date has been

recorded in the area across which survey was carried out, most notably by the Late Major Peter

Gardner of Ilmington in the late 1960s and early 1970s (Gardner and Ibbotson, 1974: 4). 141

sherds, from a number of fieldwalked sites in and around the village, were subject to initial

analyses by Paul Booth in 1987 (unpublished information in Warwickshire HER; see MWA

6338; Booth, 1987) although it remains difficult to relate particular findspots to particular

locations in this work. It is likely that Booth wrote this report after very rapid appraisal of the

artefactual material (Stuart Palmer, pers. comm.). The composition of the assemblage is largely

of greywares and Severn Valley wares. Interestingly, Booth speculates on the presence of


buildings in the vicinity of the Windmill Hill assemblage. He notes the find of a piece of combed

flue-tile, implying “the proximity of a building of some substance and sophistication” (ibid.: 3).

The reporting on the original assemblage is far from complete and the assemblage ideally

needs reappraisal; therefore, the current programme of work involved a rapid programme of

systematic fieldwalking, across the SE field of the survey area (undertaken by B. Meredith and

B. Gethin in October 2014). Additionally, metal detecting has been undertaken across this field

by local detectorists in 2014 (the finds from this programme of activity are reported on below).


Geophysical survey

Standards

The surveys and subsequent reporting were carried out in accordance with English Heritage’s

guide to Geophysical Survey in Archaeological Field Evaluation (2008), the IfA’s Standard and

Guidance for Archaeological Geophysical Survey (Draft) (IfA, 2010) and the ADS’ Geophysical

Data in Archaeology: A Guide to Good Practice (Schmidt, 2001).

Field methods

An overall survey grid was established using tapes, with reference to known points on

Ordnance Survey mapping. The irregularity of grid layout was necessitated by the irregularity of

field boundary layout across the survey area.

Data collection was carried out using a standard methodology, with data collected in 30m grid

units, with all grids walked in the same direction (E-W).

A Geoscan FM36 fluxgate gradiometer was used to conduct the magnetic survey; the sample

interval used was 0.25m with a traverse interval of 1.0m, amounting to 3600 readings per grid.

All data was logged in continuous mode. All grids were walked in a zig-zag traverse scheme.

Data processing

Geoplot software (version 3) was used to download and process the magnetic survey data.

Greyscale plots of both raw and processed data were produced in Geoplot. Raw data,

processed data and interpretation diagrams, which have been georectified in AutoCAD Map 3D

and ArcView GIS, are presented in this report as figures 1-4.

The ‘raw’ data has been subject to minimal editing to remove operator error, with data

subsequently processed to remove geological and background biases and interpolated to aid

interpretation (see appendix 1).


Results

An interpretative diagram is presented in figure 4, with some anomalies annotated for ease of

reference.

The survey has generally been successful in recording areas of magnetic enhancement of

probable archaeological origin. It is important, however, to note that a consistent fault in the

gradiometer’s data collection occurred in January 2014, causing a ‘stippling’ effect visible

across the SE quadrant of the survey area, which had the potential to mask subtler anomalies.

However, all anomalies noted were of high magnetic enhancement, suggesting that they

represent cut features backfilled with material that has been significantly magnetically enhanced

e.g. through burning and therefore are likely to represent domestic refuse material.

The main anomaly recorded in the geophysical survey was a sub-rectangular enclosure (A),

with an internal area of c.50m E-W and 60m N-S. The corners of the enclosure are noticeably

‘rounded’ especially to the NE. The level of magnetic enhancement of the enclosure ditches is

suggestive that they have been backfilled with domestic material.

In addition, discrete sub-circular peripheral enclosures (B) are visible conjoining this main

enclosure. This is clear on the NW corner and at the mid-point of the eastern side of enclosure

A. The anomaly to the south of the main enclosure is also suggested as representing a

peripheral enclosure, although its exact morphology and relationship to the main enclosure is

unclear due to the technical fault which pervaded the survey in this area (see above).

A number of possible internal features (C) have been suggested through weaker areas/trends of

magnetic enhancement within the main enclosure, although the exact nature of the anomalies is

difficult to interpret, given the limited internal area of the enclosure available for survey.

Two discrete areas of ridge and furrow ploughing are visible as clear linear anomalies in the

magnetic data. Ploughing ridges to the south (D) are aligned NNE-SSW; those to the north (E)

are aligned NE-SW. They are clearly visible on 1940s aerial photography of the area as

earthworks which are no longer extant.

It is noticeable that extensive damage has occurred through agricultural activity, most probably

associated with deep-ploughing in the 1980s which removed the earthwork remains of ridge and

furrow. The damage can be seen to have been most severe across the southern extent of the

survey area. Two significant areas of magnetic disturbance were also noted in the magnetic

survey results.


Fieldwalking

By Brian Meredith

As previously noted, a rapid fieldwalking exercise was undertaken in the SE quadrant of the

survey area, which pilot work suggested was producing a diagnostic pottery assemblage.

The pottery recovered was mainly Severn Valley and grey wares, commensurate with the

material previously recovered by Major Gardner. A small assemblage of Samian and Oxford

colour coated ware was also recovered, together was some fragments of Roman roof tile.

Two refitting fragments of saddle quern were recovered. They appear to be of Upper Llandovery

Silurian sandstone from May Hill.


Metal detected finds

By Brian Meredith

In addition, throughout 2014, a number of local detectorists have been undertaken limited

detecting on Windmill Hill. Finds have been particularly noted from the western extent of the

study area, although full find spot information has not been forthcoming.

Finds made available to Brian Meredith included:

Three brooches;

a) 1 T-shaped applied hook type AD 1-50, an early British development found mainly in the SW

in Dorset & Somerset;

b) 1 Colchester derivative rear hook bow brooch AD 43-100;

c) 1 Dolphin type bow brooch, dating to the early Roman period.

Four coins;

a) 1 Silver Trajan denarius AD 107;

b) 1 Silver Antoninus Pius denarius AD 138-161;

c) 2 radiates late third century;

d) 1 Constantine derivative coin AD 330+.

The finds assemblage also included 6 lead spindle whorls, typically dated to the Roman period.

8 conical pierced lead weights were also recorded, but these remain difficult to date although a

Roman to post-medieval date can be suggested from comparative examples (e.g.

http://finds.org.uk/database/artefacts/record/id/480937 ).


Conclusions

The results of the geophysical survey have confirmed that Windmill Hill formed a focus for early

occupation in Ilmington, with subsurface deposits associated with a single enclosed farmstead

site. The finds indicate that this originated in the Late Iron Age, continuing in a western British

tradition for some centuries into the Roman period.

The main enclosure is of sub-rectangular form, with peripheral sub-circular enclosures. Similar

enclosures have been extensively recorded as cropmarks across the north Cotswolds (Moore,

2003) and Avon Valley (Hingley, 1996). The distribution of “rectangular ditched enclosure crop

marks” is described as ubiquitous across Warwickshire (Alexander, Palmer and Chadd, 2008:

43), although several authors have drawn attention to the issues inherent is ascribing them all

the same date or function (e.g. Palmer, nd). Moore goes further in identifying “a general

impression that settlement had a greater tendency to rectilinear enclosure in the [Upper

Cotswolds]” in the Middle Iron Age-Roman period (2003: 91-92). What is clear is that they

dominate the settlement record for this period, with sub-rectangular enclosures representing

54% of the identified cropmark record for the Iron Age and Roman period across the

Cotswolds, Gloucester Vale and upper Thames valley (ibid.: 66).

The size of the enclosure on Windmill Hill is commensurate to many other examples which have

broadly been identified as representing farmsteads of single family units (e.g. Cunliffe, 2006:

283). For instance, the Middle Iron Age-Late Iron Age settlement at Park Farm, Barford,

excavated in the 1980s (Cracknell and Hingley, 1994) was first revealed as a cropmark

enclosure measuring c.60 x c.50m. It is described as an enclosed settlement with antenna

enclosures. Other more recently excavated examples have produced extensive occupation

evidence from both the enclosure ditch itself (e.g. at Whitchurch, measuring c.37 x c.25m

[Waddington and Sharples, 2011: 25-28]) and within internal features (e.g. at Marsh Farm

Quarry, with the enclosure ditch measuring c.75 x c.75m) (Palmer, 2000)1.

The finds identified through historic surface collection, in the latest programme of fieldwalking

and in the finds recovered by metal detectorists have hinted at the longevity of occupation on

Windmill Hill, spanning the Late Iron Age and Roman periods. In this context it is of note that

despite the transitional nature of much of the metalwork, there was no Gallo-Belgic ware pottery

in the assemblage. Moore has highlighted that Belgic pottery is typically missing from north

Cotswold transitional sites (2003: 44), and the picture from Warwickshire more generally is

complex, with its presence not to be taken for granted even on securely dated Late Iron Age

sites (Alexander, Palmer and Chadd, 2008: 47).

The site on Windmill Hill is of particular significance given that it has not previously been noted

as a cropmark, and was only previously recorded through fieldwalking. Away from the

1 For further examples, including comparsons of enclosure sizes, see Hingley, 1996; Palmer, nd and Alexander,

Palmer and Chadd, 2008: 40-48.


productive gravel river terraces, a picture of dense settlement in the Iron Age is beginning to be

postulated (e.g. Hurst, 2011) which has hitherto been underrepresented in the cropmark record.

Geophysical survey has provided confirmation that the fieldwalked finds clearly relate to

subsurface archaeological features here, and it has been possible to use both an historical

surface collection as well as renewed fieldwalking campaign to date the set of enclosures

revealed by the gradiometer survey. Such a site serves as a pertinent reminder of the limitations

of the cropmark record, with regard to fully interpreting site type and chronology for this period

(Palmer, nd).


Bibliography

• Alexander, M., Palmer, S. and Chadd, L. 2008 Archaeological Resource Assessment of

the Aggregates Producing Areas of Warwickshire and Solihull Warwickshire County

Council [consulted online]

http://archaeologydataservice.ac.uk/archiveDS/archiveDownload?t=arch-849-

1/dissemination/pdf/Final_Report_mainreport_pp001-165.pdf

• AOC Archaeology, 2012 Historic Environment Assessment of Local Service Villages,

Stratford-on-Avon District Council AOC Archaeology project no 32127 [consulted online]

https://www.stratford.gov.uk/files/seealsodocs/125537/Historic%20Environment%20Asse

ssment%20of%20Local%20Service%20Villages%20SDC%20-%20July%202012.pdf

• Booth, P. 1987 Roman Pottery from Ilmington, Warwickshire Unpublished report.

Warwickshire HER MWA27070

• Cracknell, S. and Hingley, R. 1994 Park Farm, Barford: excavation of a Prehistoric

settlement site, 1988 Transactions of the Birmingham and Warwickshire Archaeology

Society 98 pp.1-30

• Cunliffe, B. 2006 Iron Age Communities in Britain: An Account of England, Scotland and

Wales from the Seventh Century BC until the Roman Conquest London: Routledge

• English Heritage, 2008 Geophysical Survey in Archaeological Field Evaluation [online]

http://www.english-heritage.org.uk/publications/geophysical-survey-in-archaeological-

field- evaluation/geophysics-guidelines.pdf

• Gardener, S. and Ibbotson, E. 1974 The history of Ilmington Shipston on Stour

• Geoscan Research 2005 Geoplot Instruction Manual [consulted online]

http://www.geoscan- research.co.uk/Gp300Proc3.pdf

• Gower, J. Mawer, A. and Stenton, F. 1970 The Place-Names of Warwickshire

Cambridge: Cambridge University Press

• Hingley, R. 1996 Prehistoric Warwickshire: a review of the evidence Transactions of the

Birmingham and Warwickshire Archaeology Society 100 pp.1-24

• Hurst, D. 2011 Middle Bronze Age to Iron Age: a research assessment overview and

agenda. In: Watt, S. (ed.) The Archaeology of the West Midlands. A Framework for

Research Oxford: Oxbow books pp. 101-126

• IfA, 2010 Draft Standard and Guidance for Archaeological Geophysical Survey [online]

http://www.archaeologists.net/sites/default/files/node-files/geophysicsSG.pdf

• Key to English Place Names, 2014 Key to English Place Names [online]

http://kepn.nottingham.ac.uk/

• Moore, T. 2003 Iron age societies in the Severn-Cotswolds: Developing narratives of

social and landscape change Unpublished PhD thesis [consulted online]

http://etheses.dur.ac.uk/3682/

• Palmer, S. 2000 Marsh Farm Quarry, Salford Priors, Warwickshire: Archaeological

Excavation, 4th Interim Report, Extraction Phase 9 Warwickshire Museum Field Services

Archaeological Projects Group report 0030


• Palmer, S. nd An Archaeological Resource Assessment for the Middle Bronze Age to

Iron Age in Warwickshire and Solihull West Midlands Regional Research Framework for

Archaeology, Seminar 2 [consulted online]

http://www.birmingham.ac.uk/schools/historycultures/departments/caha/research/arch-

research/wmrrfa/seminar2.aspx

• Schmidt, A. 2001 Geophysical Data in Archaeology: A Guide to Good Practice York:

Archaeology Data Service

• Waddington, K. and Sharples, N. 2011 The excavations at Whitchurch 2006-2009 An

Interim Report Cardiff Studies in Archaeology Specialist Report 31 [consulted online]

http://www.cardiff.ac.uk/share/resources/Whitchurch%20interim%20Web.pdf


Appendix 1: Technical data

1. ‘Raw’ Data

Clip (limits maximum and minimum values for display and subsequent processing): -5/+5 nT

Zero-Mean Grid (sets the background mean of each grid to zero; removes grid edge

discontinuities)

Zero-Mean Traverse (sets the background mean of each traverse within a grid to zero; removes

striping effects in the traverse direction)

2. Processed data

Despike (removes large anomalies above a certain threshold): x-radius 1; y-radius 1; threshold

2

Interpolation (smoothes greyscale appearance by adding extra data points into the dataset,

calculated with reference to surrounding collected data) on both the Y and X-axis.

For more technical information on data processing, see (Geoscan Research, 2005: Chapter 6).


FIGURE 1: SURVEY LOCATION


FIGURE 2: MAGNETIC DATA GREYSCALE (RAW)


FIGURE 3: MAGNETIC DATA GREYSCALE (PROCESSED)


FIGURE 4: INTERPRETATION PLAN


FIGURE 5: LIDAR DSM, SHOWING TOPOGRAPHIC LOCATION OF SITE.

Geophysical Survey data overlain on LiDAR DSM (ASCII and JPG data from Geomatics Group). Viewed from W, 1.8x vertical exaggeration.

Ilmington Geophysics

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