Appendix Jiii

Effects of past and present ploughing on the prehistoric monuments:

the Wyke Down, Cranborne Chase, Dorset, case study.

C A I French

Oxford Archaeology May 2002 (revised December 2002)

© C A I French, 2001

Effects of past and present ploughing on the prehistoric monuments:

the Wyke Down, Cranborne Chase, Dorset, case study

C A I French

(6/12/2001)

Introduction

Palaeoenvironmental and geoarchaeological fieldwork focusing on the later Neolithic-earlier

Bronze Age periods in the Wyke Down area of Cranborne Chase in Dorset (Figs. 1-3) is in

the process of gathering new data with which to re-examine the landscape models put

forward by Barrett et al. (1991a and b) and Barrett (1994) for Wessex. In the process,

this project has revealed data relevant to the past and present erosion of prehistoric

monuments which is ostensibly associated with past and present arable agriculture.

To date a selection of prehistoric scheduled monuments on Wyke and Bottlebush Downs

(Fig. 2) have been sample investigated to retrieve archaeological and palaeoenvironmental

data. This has been combined with geomorphological survey of the Allen valley.

Results

Introduction

Four barrows of the Wyke Down group (SAM 299 c, f, g & i) and a length of the

Dorset Cursus on Bottlebush Down (SAM 310) have now been investigated through a

combination of hand augering, topographical and geophysical surveys and sample

excavation.

The Wyke Down barrow group

The main part of the Wyke Down barrow cemetery was evaluated by topographical and

magnetometer surveys of about 1 hectare in extent (Figs. 4-6). These clearly show barrow

44 (bottom left) and 47 (top left) upstanding with evident internal features, but the remainder

are ostensibly ploughed out with only ring-ditches surviving as earthfast features.

The conventional topographical, magnetometer and resistivity surveys of barrows 34,

36, 41 and 44 pin-pointed with great accuracy the position of the ring-ditches, the

extent of the surviving mounds, and areas of antiquarian and plough disturbance (Figs.

7-14) (GSB 1998, 1999 & 2001).

Barrow 41

Barrow 41 was much destroyed and denuded, and to a large extent this had already

occurred in the past. Today the monument survives as a small, low (c 80cm high), turf

mound in the centre of the area enclosed by a ring-ditch (Fig. 7). The ring-ditch is

about 3.5m wide, 1.6m deep, with an internal diameter of about 19m and an external

diameter of about 26m. The inner third of ring-ditch backfill was composed of densely-

packed, clean chalk rubble which would appear to be a deliberate backfill deposit. One

could speculate that this chalk substrate material had acted as either a cap to the turf core,

or as a circular bank on the inner edge of the ring-ditch, which had been deliberately put

back into the ditch after a short period. Thus this barrow has probably previously been two

slightly modified versions of a disc barrow.

There is a difference of about 25cm between the level of the chalk on the outer edge of the

ring-ditch and the chalk subsoil beneath the surviving mound (Table 1). The mound itself

has become elongated along the east-west direction of the property boundary between the

Shaftesbury Estate to the north and Martin Green’s land to the south (Figs. 7 & 8).

Barrow 34

Barrow 34 was exhibited a more complicated and diverse sequence than barrow 41.

Despite the presence of the large antiquarian trench on its northern side (which may be early

20th century in date, and is regrettably unrecorded), the mound of this barrow appears to

be substantially intact and standing to a height of about 1.6m above the present day surface

(Figs. 7-9 & 11).

Sample excavation revealed that the site was comprised of at least two superimposed

barrow monuments associated with first an inner and then an outer ring-ditch. First, a small

(c 2 x 3m), sub-rectangular chalk cairn was erected on a thin (<10cm), truncated old land

surface. This cairn would appear to mark the centre of the subsequent mounds and was

covered by one or two layers of turf. The inner ring-ditch (of about 18m internal diameter)

was then dug (or deepened), and the chalk subsoil upcast from this was used to make a

primary chalk mound of about 16m diameter placed over the primary chalk and turf cairn.

The surface of this chalk mound was initially left bare and underwent a period of weathering

sufficient to discolour the upper 5-8cm of the chalk, and saw the accumulation of large

quantities of worked flint, probably worked in situ. Then, a more substantial turf mound

was created with its outer edge vertical sided and retained by a slight wooden revetment of

stakes (slender fence post size, <10cm), with each stake placed about 40cm apart,

presumably retaining a woven wattle-work fence, located about 1m in from the inner edge

of the ring-ditch. The inner ring-ditch had become completely infilled by the time the outer,

slighter, ring-ditch was dug (with a c 23m internal diameter, c 24.5m external diameter). The

mixed upcast of turves, soil and chalk rubble produced by the digging of this ditch was

thrown-up against the outside of the wattle fence around the first barrow, which was now

leaning outwards, thus increasing the diameter of the barrow mound by about 3m and

creating a gently sloping outer edge to the barrow, but still leaving a wide berm (2.5-3m).

Apart from the antiquarian disturbance of the north-central part of the barrow mound,

ploughing over different time periods has differentially affected its northern and

southern sides (Figs. 7-9). The mound survives to a maximum height of 1.6m above

the modern ground surface. On its northern side, the mound rises abruptly from the flat

level of the present day ploughsoil where it has been ploughed for a 45 year period. In

contrast, the southern side, which has not been ploughed for the past 15 years and is

under established grassland, exhibits a more gentle sloping aspect between the edge of

the surviving mound and the inner edge of the outer ring-ditch. This mound talus slope

exhibits a 56cm thickness over a distance 6m (Table 1).

Barrow 36

Sample excavation of barrow 36 revealed a thin rendsina soil profile (c 12-15cm thick)

overlain by a thick turf core and substantial dumped chalk mound, as was indicated by the

auger survey. The mound was about 25m across north-south and 23m across east-west,

and has the best height survival at 2.45m. Essentially, the mound has become sub-square in

plan (Figs. 12, 14-16). The single ring-ditch was about 2.5 m in width and 1.3m in depth.

Significantly, the berm area between the inner edge of the ring-ditch and the outer edge of

the surviving mound exhibited three steps in the upper level of the chalk subsoil. The first

step was of 10cm between the outer and inner edges of the ring-ditch, then about 1.5m in

from the inner edge of the ring-ditch there was a second step of 15cm and then another

metre in there was a step of 27cm at the outer edge of the surviving mound. This gives a

total figure of 52cm of truncation over a width of about 5m in the level of the chalk subsoil

on the east side of the mound (Fig. 17; Table 1). The field in which this barrow sits is

known to have been ploughed for 45 years (P Rymer and M Green, pers comm.), and has

apparently caused the significant denudation and re-shaping of this mound.

Barrow 44

Sample excavation of barrow 44 revealed very much the same picture as for barrow 36, but

the mound and buried soil were less well preserved (Figs. 13, 14 & 18). The mound

exhibits a diameter of about 27m across east-west and 18m across north-south, and has

effectively become sub-rectangular in plan. The single ring-ditch was about 3.2m in width

and 1.35m deep.

This barrow mound survives to a maximum height of 1.33m and has suffered severe rabbit

warrening and possibly an antiquarian trench being placed in its northwestern quadrant. As

for barrow 36, it too exhibits three steps in the level of the chalk between the inner edge of

the ring-ditch and the outer edge of the surviving edge of the barrow mound. In this case,

there are steps of 7, 18 and 53cm giving a total figure of 78cm of denudation (Fig. 18;

Table 1).

The Dorset Cursus

Four sample sections were excavated through the northern and southern cursus ditch

and bank on the c 1km stretch leading to the Bottlebush Down terminal (Figs. 15, 16,

19 & 20). Unlike those sections previously excavated by Richard Bradley (Barrett et

al. 1991: figs. 2.12 & 2.13), these new sections revealed fills that were mainly

dominated by clean chalk rubble. Moreover, the surviving bank was much denuded in

height (i.e. less than 30cm) and appeared to have been ploughed in pre-Roman times.

From the 2001 field investigation it looks as if the Bottlebush Down length of both

cursus banks was deliberately slighted back into the ditch shortly after the monument

was constructed. This is in contrast to the other fill sequences observed further to the

south in the same monument on Wyke Down and in Firtree Field by Bradley (ibid.)

where the homogeneous organic silt loam and fine chalk rubble fills suggested a natural

infilling over a lengthy time period. These observations in the northern sector of what is

believed to be the first major length of Dorset Cursus would suggest a complete change

in its importance and function in the landscape within the later Neolithic. In addition, it

may imply a complete re-aligning of the fields and boundaries in this part of the

downland landscape.

As an important addenda to this work, the sample excavations enabled the assessment

of the preservation of this important linear field monument. Although only part of the

southern bank/ditch of the cursus is scheduled in this stretch from the terminal

northwards, the whole length is quite poorly preserved. Modern ploughing, post-17th

century AD estate boundaries and scrub woodland development have all played a hand

in the destruction of the northern and southern banks. In addition, there were several

ard marks preserved beneath the Roman Ackling Dyke and the cursus northern bank in

one assessment trench which may also indicate some later prehistoric slighting and

denudation of what was left of the cursus bank in places (Fig. 19). A major observation

of this field season was that both cursus banks in the c 1km length investigated were

severely slighted, probably in the late Neolithic period and again in preparation for the

construction of the Roman Ackling Dyke in the 1st century AD. Indeed, where the

southern cursus bank appears to be very prominent and well preserved and it is

therefore scheduled, there is the same slighted bank, accentuated by the later creation of

a property boundary, and plough downcutting creating a false contour on its eastern

side (Fig. 20).

Table 1: Observed amounts of truncation at four barrows of the Wyke Down group.

Truncation stage: Barrow site:41 34 36 44

Surviving mound height 0.8m 1.58m 2.45m 1.33m

Truncation step acrossring-ditch - - 10cm 7cm

Truncation step on berm - on north: 15cm 18cmc 30cm; onsouth: gentleslope over 6m

Truncation on outer edge c 25cm (as above) 27cm 53cmof mound

Total truncation c 25cm c 30cm 52cm 78cm

Conclusions

Ploughing in both prehistoric and recent times has resulted in varying degrees of

destruction of upstanding scheduled monuments in the Wyke and Bottlebush Down

areas of Cranborne Chase. These conclusions are fully attested by topographical and

geophysical surveys and test excavations (French et al 2000).

Both the northern and southern banks of the Dorset cursus have been affected by the

deliberate back-filling of the ditch with bank material as well as pre-Roman ploughing.

The cursus banks occasionally survive to a thickness of about 25-30cm where they are

protected either by other monuments or later field boundaries. Where they are

unprotected and have been ploughed for at least the past 45 years, no earthwork

survives, there is only a dissipated linear scar visible in the field today.

The Wyke Down barrow group consists of only seven upstanding barrow mounds out

of a total of at least 29 ring-ditch sites. The ploughed out barrow mounds are just

visible in the field under the right light conditions as very slight rises in the field, but are

not otherwise detectable.

Ploughing since the latter 1950s of the scheduled and upstanding barrows has resulted

in the sculpting of the mounds resulting in ovoid to sub-rectangular to sub-square

shapes to the once circular mounds.

In addition, this same ploughing has created truncation steps around at least four

barrows, with up to c 25-78cm of chalk subsoil having been scoured away over about

45 years. This has particularly affected the ring-ditch, berm and outer edges of the

mounds, and is particularly marked in barrows 36 and 44.

In one case at barrow 36, the conversion of former arable land to pasture for the last 16

years has dramatically slowed this truncation process on its southern side. It has

resulted in a less abrupt and more gently sloping talus edge to the surviving barrow

mound, which better reflects the natural collapse and erosion of the mound over time.

1. Figure 1: Location map of the study area in southern England (H Lewis).

Figure 2: Location map of the research area showing the Wyke Down barrow group,the auger transects and the relict stream channel areas (scale 1:25,000; after theOrdnance Survey of England and Wales) (H Lewis).

Figure 3: Terrain map illustrating the drift geology and prehistoric sites (red = henge;blue = ploughed out barrow or ring-ditch; blue lines = Dorset cursus; yellow =upstanding barrow).

Figure 4: Location map of the topographical and geophysical survey areas of the WykeDown barrow group (GSB Prospection).

Figure 5: The contour plan of barrows 44 to 47 of the main part of the Wyke Downbarrow group (P White).

Figure 6: The magnetometer survey of barrows 44 to 47 of the main part of the WykeDown group showing a much greater number of ploughed out barrows and ring-ditches(GSB Prospection).

Figure 7: The contour survey of barrows 34 and 41 (P White).

Figure 8: Mesh terrain model of barrow 41 (foreground) to barrow 34 (P White). Thefield on the right hand side of the property boundary has been pasture since 1985, andthe field to the left has been ploughed since 1958.

Figure 9: The contour plan of barrow 34 with the location of the sample trenches andauger transects (P White).

Figure 10: The contour plan of barrow 41 with the location of the sample trenches andauger transects (P White).

2. Figure 11: The magnetometer survey of barrows 41 (Area A) and 34 (Area B)(GSB Prospection).

Figure 12: The topographical survey of barrow 36 (P White).

Figure 13: The topographical survey of barrow 44 (P White).

Figure14: The combined magnetometer and resistivity surveys of barrows 36 and 44(GSB Prospection).

Figure15: Oblique aerial view from the northwest of the Wyke Down barrow group,Wyke Down henge and part of the Dorset cursus (M Green).

Figure 16: Oblique aerial view from the north of barrow 36 (centre) and part of theDorset cursus (M Green).

Figure17: Evaluation trench across the ring-ditch, berm and eastern edge of the moundof barrow 36, showing the three truncation steps in the level of the chalk subsoil.14.

Figure18: Evaluation trench across the berm and the southern edge of the mound ofbarrow 44, showing the two truncation steps in the level of the chalk subsoil.

Figure 19: The ploughed out northern bank of the Dorset cursus (right) and the agger ofthe Roman Ackling Dyke with ploughmarks beneath.

Figure 20: The ploughed southern bank of the Dorset cursus on Bottlebush Down.

Acknowledgements

The results of this project have been made possible through the co-operation of Mr P

Rymer of the Shaftesbury Estate and Martin Green. Funding for the fieldwork is gratefully

acknowledged from the Arts and Humanities Research Board and the McDonald Institute

for Archaeological Research.

References

Barrett, J, 1994, Fragments from Antiquity : An archaeology of social life in Britain,

2900-1200BC, Blackwell, Oxford.

Barrett, J, Bradley, R and Green, M, 1991(a), Landscape, monuments and society: The

prehistory of Cranborne Chase, Cambridge.

Barrett, J, Bradley, R and Hall, M, 1991(b), Papers on the Prehistoric Archaeology of

Cranborne Chase, Oxbow Monograph 11, Oxford.

French, C, Lewis, H, Allen, M, Scaife, R, 2000, Palaeoenvironmental and

archaeological investigations on Wyke Down and in the upper Allen valley,

Cranborne Chase, Dorset: Interim summary report for 1998-9, Proceedings of the

Dorset Natural History and Archaeological Society 122, 53-71.

GSB Prospection, 1998, Wyke Down, Gussage St Michael, Dorset, Geophysical Survey

Report 98/65, Bradford.

GSB Prospection, 1999, Wyke Down II, Gussage St Michael, Dorset, Geophysical

Survey Report 99/99, Bradford.

GSB Prospection, 2001, Bottlebush Down, Sixpenny Handley, Dorset, Geophysical

Survey Report 2001/87, Bradford.