In the survey from the Zig Zag in Chawton Park Wood the 28 degree North of Grid East direction of this Road was continued by an air photo streak of a dark line bounded by light lines, reported in Ref 1. Although a Roman Road is expected to give air photo streaks of light lines (stone work) bounded by dark lines (ditches), these streaks connected with the more regular streaks found in subsequent surveys (Ref 2). So excavations were carried out on the western edge of Chawton Park Wood, as the streaks enter Roe Downs Farm. Due to the nature of the streaks it was appreciated that something unusual was likely to be found. Dark lines bounded by light lines may be a two lane highway with a ditch in between. Such multi-lane Roman Roads have been the subject of other investigations (Refs 3).
The excavations were carried out over 2006 - 9 in a narrow strip of wood owned by Roe Downs Farm, comprising the edge of the wood, along which the parish boundary of Chawton and Medstead runs. On clearing the land the parish boundary ditch was found, giving just enough room for a 1 meter trench by the Farm's boundary, which was taken as the base line - this boundary being one of those at right angles to the Road. It was also found that the land had been levelled to put the parish boundary on. This has been found on a much steeper slope in the Crondall Boundary Study in the region of Caesar's Camp near Farnham (Ref 4), and is being found in the Chichester Roman Road project, and is the subject of a separate study. It does not appear to be known that even on slight slopes such as on the edge of Chawton Park Wood the Saxons would have constructed a terrace for their boundary bank and ditch. Such construction may have caused some disturbance to the Road, including robbing of the stone metalling.
It was appreciated that the OS map on which the Roman Road survey was plotted (Ref 1) did not agree with the air photos given in this Reference. Some map error occurred, and it was not possible to fix exactly where the air photo streak (Feature 5) cut the wood - field boundary. Trenches were laid out from 12N to 20S to allow for this error, designed to pick up the air photo features. The 00 position was 87.07m from the northern field boundary (Point A on the survey map). In the event it was only in the last southerly 4m of this trenching that a band of packed flints came up (Trench 8, 16.8 to 20S). A subsequent survey, using the OS/RAF 1947 - 9 6": 1 Mile air photo, showed that this band was the northern light air photo line (Ref 5).
For 2009 excavations the trench was extended to encompass the expected position of the southern light line. The Composite Sections, positions of the light and dark light lines, and the stone counts, are given below. [These images will print across an A4 page with margins less 0.75" 19.1mm. At the end of this report facilities are available to print out full size landscape copies of these diagrams which can be fitted together]
Caption for Drawings 12N - 12S. The upper of the three diagrams is the Composite Section Drawing. The centre diagram shows the position of the air photo streaks on the ground, light lines shown as dashed or dotted lines. The Stone Count is the bottom diagram of fist size and larger stones per cubic meter of excavated trenches. Base Line origin is at SU66907 36516
Caption for Drawings 11S - 36S. The Packed Flint Layer found in excavation from 16.8S - 20S in Trench 8 is shown as closely spaced dots. The more loose flint layer below is shown as more widely spaced dots. Re-deposited clay is shown as R. Except for the Top Soil, and Clay in the 3 positions shown, all layers between 20S - 36S are subsoil - much of which is light in colour shown L. Boundaries with other coloured subsoils are shown. The light air photo line between 30 - 34S did not show in the region of the excavation.
The Composite Section Drawing in the top diagrams from 12N - 11S appears to show natural stratigraphy, largely undisturbed, except for two pits cut down to the natural clay. There is a thin Top Soil typical of woods, 20 - 30cms of subsoil, which gradually gets redder as it merges with the clay natural. Stones which were visible in the section are shown, as are boundaries of pits or ditches seen from section photographs. Finds were almost only worked flint, which were common.
The Composite Section from 13S to 36S is very different:
From 15S to 17S in Trenches 7 & 8 there is a layer of buried Top Soil, with its base at much the same level as the natural clay surface before it starts to rise up towards the surface in Trench 7. This means that the clay above this buried Top Soil layer is Re-deposited, and likely to result from the natural clay south of 18S being dug out some 30 - 35cms deeper, some of which was piled up on the edge of the resulting ditch, burying the natural ground surface. Clay judged to have been Re-deposited is show as R on the Composite Section.
The interpretation is that these thick subsoil layers result from silting up of the large ditch. The fact that the silting up is subsoil not Top Soil (the Top Soil layer here is slightly thinner than the northern trenches) dates the digging out of the ditch to medieval or earlier - subsoil takes around 1k years to form. We expect to find Roman layers near the top of the subsoil. The other subsoil layers may result from re-cutting of the ditch when it was in use - the upper light subsoil layer resulting from silting up after abandonment. In other excavations we have found that Roman ditches are generally re-cut several times, and tend to end narrower and shallower. Such ditches have tended to be recognised from the different coloured subsoil fill - such subsoil being young compared with the ancient naturally occurring subsoil. We have not found a consistent pattern in this colour difference - but very young subsoil might be expected to be light especially where it is far removed from the red clay.
The centre drawing shows the position of the dark air photo line reported in Ref 1 as bounded by two light lines. As expected this dark line corresponds with the deeper subsoils of the silted up ditch - except that it was expected to end around 30S. However, clay was only found at 65cms below Ground Surface at 35 - 36S, indicating that the ditch continues further south. Re-examination of the air photo indicates that this dark line extends further south. Further, photographic evidence from the field west of the excavation shows this ditch as a depression between two swelling extending to 44S http://www.nehhas.org.uk/pxro09.htm.
The problem is that these flints do not show up in Section - those flints seen on the Section face are shown. However the section photographs show clearly upper and lower boundaries which are coincident with the packed band of flints found in the excavation. The upper is the boundary with the light subsoil discussed above, the lower is a boundary with dark red subsoil or re-deposited clay - between them is a much lighter red material. These boundaries have peculiar features: (i) they are exactly level - whereas there is a slight slope of the whole stratigraphy down to the north - it is thought only the Romans could be responsible for this; (ii) the southern lower boundary tapers in a straight line to meet the upper boundary at just over 20S (explaining why we found the packed flints in Trench 8, but not at all in Trench 9).
In reports of nearby excavations there has been much discussion on advice we were given by flint in clay experts that flints will rise up in clay environments. Thus any pattern they may originally have had is liable to be randomised with time (Ref 6). In these other excavations however we have been able to find a packed layer in section in some undisturbed conditions. There has been disturbance here due to the construction of the parish boundary - but this section will be the least disturbed by it. The interpretation is therefore that the packed flints have undergone some such movement so that they may be seen in excavation but not necessarily in section. There are more flints seen in the section in this region, but they do not obviously conform to the boundaries of the packed layer. The boundaries themselves show in section, and there is a different coloured material where the packed flints were. And of course the Stone Count indicates far more stones in the trench where the packed flints were found in excavation.
While the dark air photo line as expected was a wide silted up ditch, it appears to extend beyond the southern light line expected around 32S. So the air photos were re-examined.
On the OS/RAF 1947 air photo the Dark Line through woods and fields to the drive of Roe Downs House (Feature 5) is composed in the woods of the absence of white specs seen elsewhere, width 75' - 80'. In the centre of this Dark Line are thin intermittent Light Lines in wood and fields. The Dark Line is bounded by faint Lighter Lines with more white specs than elsewhere in wood and fields. The Northern Light, width c 30', has a dead straight boundary with the Dark Line, and has a strong thin light line here in the fields near the wood boundary. This faint Northern Light leads back over Features 4.
The faint Southern Light Line is not so clear, may be narrower than the Northern, and also narrows towards Roe Downs House - where the Dark Line also tapers towards the straight boundary with the Northern Light. There may be a thin stronger light line with the boundary with the Dark Line in the fields, but it is less clear. What was recognised for the Survey Map (Ref 1) was the strong thin Northern Light Line, and the intermittent Light Lines in the centre of the Dark Line. But it is clear that the 80' Dark Line extends further south than initially recognised, and its width agrees with picture of the swellings and depression (78').
The MultiMap air photo (70% Contrast) shows two thin light lines in the fields c 40' apart, the southern one being the Northern Thin Light in the OS/RAF air photo - and between them mark the position of the faint Northern Light Line.
The position of these lines is shown in the centre drawing below the Composite Section. No evidence occurs in the excavation or Stone Count for the faint Northern Light, nor the MultiMap thin northern light (shown ?). However, the profile of the ground for the Northern Swelling (see picture of drill line in the field) seems to start at 6S - so possibly these swellings are responsible for these faint Light Lines.
As the stronger thin light lines are intermittent, they may only survive in places. Possibly as the excavation suggests they are narrow metalled lanes of a two or three lane highway - but each may have less chance of surviving than one metalled lane three times the width.
Magnetometary
As part of the students' exercises, magnetometary was conducted in the field to the west of the excavation - the area shown in the above picture - but at the time we were not aware of the Southern Swelling. However, the magnetometer traverses started at 56S, with the centre of the Southern Swelling at 44S. The computer plots of the traverses do not shown clear results. There is a tendency for the signals to increase going north. The Farmer, Mr John Cray, says that his fertilliser is very accurately laid, but sewerage sludge has also been applied - which is not evenly laid. This may create a lot of noise.
So the individual traverses were examined to see their behaviour over the two Swellings (assumed Light Air Photo Lines due to stone metalling), the Central Air Photo Light Line and the Dark Line (Ditch either side of the Central Light Line). We thus have three Light Lines which may be metalled Roman Road Lanes - Southern, Central, and Northern (where the packed flints were found in excavation); and two Ditches, Northern and Southern between these Light Lines. Signals should go down over the Stone Lanes, and go up over the Ditches.
Results of this traverse examination for the Light Lines as three potential stone Roman Road Lanes
Northern Light Line - Packed Flint Band: 15 / 21 Traverses show evidence of fall
(10 definite)
Central Light Line - depth not reached in dig: 15/21 Traverses show evidence of fall
(9 definite)
Southern Light Line - not reached in dig: 14/19 Traverses show evidence of fall
(11 definite)
For the two parts of the Ditch either side of the Central Light Line:
Northern Dark Line - Ditch found in dig: 15/21 Traverses show evidence of rise
(14 definite)
Southern Dark Line - still Ditch at 36S: 13/19 Traverses show evidence of rise
(9 definite)
There is some evidence that stone work lies under the two Swellings, and in the centre of the Ditch. Furthermore of the 6 traverses which did not show evidence of a rise in Signal for the Northern Dark Line/Ditch, 5 of them were together at 18 - 23W. Likewise the 5 traverses which did not show evidence of a rise over the Southern Dark Line were also together in the same region as the Northern Ditch - 19 to 24W. This may be due to the Centuriation Cross Road shown on the Survey Plan in Ref 1, where either the Ditch was not dug to allow this Road to cross, or the increased stone work of this Road removes the increased Signal. Both these issues warrant further investigation.
The Farmer, Mr John Cray, was interested to know if our magnetometary would show evidence of the ditch over his fields near Road Downs Road. As these field were short grass he suggested we do a quick skim taking averages rather than recording all readings. A method was devised by dividing Traverses into bands where we might expect to see changes, then moving the loop quickly over the ground, noting the typical max and min swings of the needle. The average of these swings were plotted for each band, given below. Where definite changes of Signal occurred on a Traverse, further bands were created.
Caption for Magnetometary Plots. The Traverses were 2m apart. The upper (Western) Group started
20m from the boundary with Roe Downs House, the lower (Eastern) Group started 16m from the field boundary.
The Discriminator was adjusted to give readings in the 30 - 50 range on the Meter - and had to be adjusted for
some Traverses. The Threshold was set at 10, and the Scale of the vertical plots of the Signal from 10 - 60
is shown above. Signals below 10 (negative) are not shown.
In this field with this method a clearly larger Signal is seen over the ditch position. In particular, all the Traverses show a fall off towards the background Signal between 16S - 20S (the northern end of the ditch and packed flint layer found in the excavation). This mirrors the finding above that the northern boundary of the dark air photo line is sharp and straight. The southern boundary of the larger Signal is more ragged, and in the region of 31S - 37S - rather than 44S suggested from the picture of the Southern Swelling. However it does tally with the above finding that in this field the air photo dark line is narrowing towards its straight northern boundary.
The dark air photo line is last seen just across Roe Downs Road. Magnetometary at the other side ot this field around Feature 6 on the Survey Plan found no evidence of higher Signals.
Conclusion
A major feature has been found, where a broad ditch with the natural clay dug into 30 - 40 cms runs for 1/3 of a mile, from near a Roman Zig-Zag, up a narrow valley bottom to the summit of the downs. Some of this clay has been piled up on the edges of the ditch, where a narrow stone metalled strip has been constructed at one and probably both edges. Another similar metalled strip is expected at the centre of the ditch. While this may give a three lane Roman highway, of combined width of over 30' - rather larger than the usual width - it is not understood what the purpose was of this arrangement. The work would be substantial to construct a 90' wide ditch, and this arrangement has not been found before. The line is here entering a Roman Centuriation of estate Roads - where construction methods may be different. On the continent they were thought to be un-metalled levelled ways between two ditches. In our Winchester Centuriation we think they were metalled - for example on the Survey Plan the southern route shown has air phto streaks of the usual light line bounded by dark lines.
Acknowledgements
Thanks are due to Mr John Cray for permission to excavate on this land and for clearing trees; and to the 187 man days contributed by the diggers. Richard Whaley
REFERENCES
1. Richard Whaley, Into the Centuriation, NEHHAS Newsletter No. 96, Summer 2005; NEHHAS Journal Vol 3, No. 12, 2007.
2. Richard Whaley, NEHHAS NL No. 98 Spring 2006, Jn Vol 3, No. 13, 2007
3. Richard Whaley, NEHHAS NL 108, Autumn 2008; CBA Wessex News Spring 2009
4. Richard Whaley & Geoff Hoare, NEHHAS Jn Vol 2, 2002 p17
5. Richard Whaley, NEHHAS NL No.109, Winter 2008/09.
6. Richard Whaley, Flints on the Roman Road NL 98, Spring 2006; Excavations on a Centuriation Cross Road NL 98, 102, 106.
Click here for Trenches 1 - 7 then check your margins 18mm and set to Landscape [File - Print Set-up - Landscape, Margins 18mm. File - Print..] Click here for Trenches 7 - 12
After Printing, re-set to Portrait and default margins.
The two prints will fit together to give a complete Composite Section.