CROW CLOSE
ANALYSIS OF RESULTS
Using the geophysical results in combination with the air photographs and topographical survey it is possible to make an interpretation of some of the earthworks that are visible in this field. The magnetic and resistance survey results are shown overlain in Figure 17, while the main elements of the analysis are shown in Figure 18.
Ridge and furrow
Extant ridge and furrow may be observed on the laser plan as a series of broad, low, linear earthworks (brown dashed lines in Figure 18) running approximately west-east across fields G, H and I in the eastern part of the field and running approximately north-south in fields B, C, D and E in the northern part. In the SE corner of the geophysics survey area these earthworks correlate closely with broad positive and negative linear striations [M5] in the magnetometer plot, but are invisible in the earth resistance plot. These broad striations end at a N-S curvilinear positive magnetic anomaly short of the hollow way, the significance of which is uncertain.
Hollow-ways
The substantial surviving earthworks of the hollow-ways (parallel blue lines in Figure 18) that converge towards the centre of Crow Close emerge clearly in the magnetometer plots as wide bands of disturbed magnetic response (Figures 13 and 14). In the E-W hollow-way there are two areas of large dipolar responses that are usually indicative of ferrous or highly fired material. These may be indicative of later activity as these are close to the World War II installations. The courses of the hollow-ways may also be partially tracked on the basis of variations in earth resistance, reflecting fluctuations in the moisture content of associated banks and ditches. The western survey area (Area 1 in Figure 16) revealed an elongated area of varying response that may be related to the earthworks associated with the hollow-way (Figure 16). Resistivity survey of the eastern block (Area 2 in Figure 16) revealed a broad band of varying response, running SW-NE across the survey area (Figure16), that correlates mainly with the eastern bank and to a lesser extent with the ditch and opposing bank of the north-south hollow-way.
Field and property boundaries
The laser plan shows clearly a rectilinear pattern of ditched boundaries (yellow on Figure 18), sometimes flanked by low banks, extending across the entire field. These boundaries define 14 fields (A to L) visible on the laser plan. These features are of uncertain date, but many appear to have been appended to the hollow-ways. The linear boundaries to field H may be seen to cut obliquely across a block of ridge and furrow earthworks extending across the SE corner of the field, implying perhaps a post-medieval date for these features. One of these boundaries, between fields H and I, also cuts across the southernmost of several low, sub-rectangular earthworks that might mark the locations of building platforms. Linear boundaries between fields B to E appear to be parallel to the ridge and furrow. On the ground the ridge and furrow is difficult to measure and no conclusions can be made about the chronological relationships between the ridge and furrow and these boundaries. On one of the many air photographs of Crow Close these boundaries (between fields A to E) can be seen to extend northwards into what is now a built up area.
Field F in the north-eastern part of Crow Close is difficult to interpret. The laser plan does not show any distinct ridge and furrow and while the southern and western boundaries appear to be ditches the field itself is divided up into six parts by relatively straight features visible both on the laser plan and the air photographs. These have not been picked out by any coloured lines on Figure 18. They could be younger than any other boundaries in the field. The two at the eastern end of this field appear to be truncated by the modern field boundaries, which are present on the tithe map of 1841, but there is no earlier information about them.
Most of the linear boundaries on the laser plan may be shown to correlate with linear magnetic anomalies although some extant earthworks were not mapped by magnetometry. Conversely, the magnetometer survey also identified a number of boundaries that are not clearly discernible on the laser plot, notably in the area immediately east of Survey Area 1 in Field C. The earth resistance survey failed to locate the linear ditches recorded by laser and magnetometer survey in the western survey block, but recorded two linear features in the eastern survey area that were detected by neither the laser nor the magnetometer survey.
The boundary between fields K and L is marked by a broad, slightly curved depression visible on the laser plan and air photographs. A dendritic set of linear positive magnetic anomalies partly coincides with this depression, which is unlike any of the other responses to ditched boundaries. These are the only two fields in Crow Close for which there is other evidence of their existence. They coincide with two closes on the conjectural 1586 map and may have been separated by a hedge, rather than a ditch and bank, giving an entirely different geophysical response to the other boundaries. In 1586 field L was called The Grene (Figure 18) and the tenant was Robert Simpson. It was 0.8 acres in area and described as being bounded by Husband Street to the south and the by close (field K) to the east. Field K was 0.86 acres in area and was described as a by-close. This was demesne land worked for the lord of the manor by Nicholas Selby. It also was described as being bounded by Husband Street to the south, but with freeland by Robert Porter to the east. Although the 1586 map is a construction from a text based manorial survey, the placement of these two closes in the south western corner of Crow Close is difficult to challenge.
The results summarised above emphasise the complementary nature of magnetometry and earth resistance. Together with the laser data, they suggest a complex sequence of landscape change spanning the medieval and post-medieval periods. Documentary and cartographic research contributes to the clarification of the chronological relationships of the various land allotment features revealed during survey, but ultimately only excavation might unravel the complex sequences implied by these data.
Medieval Settlement focus?
The laser plan and air photographs reveal denuded and poorly defined sub-rectangular earthworks, focused upon the junction between the hollow-ways that might conceal the foundations of buildings. Structures revealed by geophysics and the laser survey are shown in red; those with no geophysical signature are shown in green. The southernmost of the two larger ones, which is approximately 18 metres square, appears to have been truncated by a west-east linear boundary cutting obliquely across ridge and furrow, but providing no other obvious stratigraphical relationships that would assist dating. Magnetometer and earth resistance data would support the case for buildings at this location, although the data are not easily interpreted. Several linear positive and negative magnetic anomalies may be shown to correlate with earthwork features, some of sub-rectangular shape (notably M6; also M7-M10); it has been suggested that these could signify associated ditches or structural remains (see earlier). M6 is situated over distinctive earthworks visible on air photographs and seems to be the southern part of a building measuring 13metres by 26 metres. No anomalies displaying magnetic signatures diagnostic of hearths or kilns were recorded, but several localised positive magnetic anomalies might signify pits or areas of burning (notably M11-M13).
The resistance survey in Survey Area 2 recorded a number of high and very high resistance linear anomalies (R12-R16). Some of these form rectilinear arrangements, which might signify building foundations, but others are irregular in plan and might represent evidence for other features such as tracks or paths. The survey also recorded several amorphous spreads of high and very high resistance (R17-R25) that it has been suggested might also indicate rubble spreads.
The rectilinear high and very high resistance anomalies, though they are in the same area as the magnetic anomalies, do not coincide and hence may be reacting to different features. Resistance anomaly R13, for example, is smaller than and inside magnetic anomaly M6. Resistance anomaly R12, which is almost a perfect rectilinear shape, has no associated magnetic anomaly. Magnetic anomaly M9, which is half of a rectangle, has no associated resistance anomaly.
The two large buildings verified by geophysics are more likely to be the remains of large houses than medieval farmhouses with the possibility that the two are of different ages. Their orientation is wrong for churches. On air photographs the northernmost of the two appears to have well defined stonework lower courses. The smaller structures suggested by geophysics nearby (Figure 18) might be part of a complex of farm buildings associated with the large house. Evidence for anything that could be interpreted as medieval farmhouses is lacking in the geophysics. Four sites visible on air photographs and the laser plan (green structures in Figure 18) situated around the central triangular field (field M) are possibly house platforms, but they are poorly represented, if at all in the geophysics plots. Feature number 4 is associated with a cluster of large dipolar responses, which may be indicative of ferrous or highly fired material. Number 3 coincides with a patch of amorphous very high resistance, which is difficult to interpret, but on the air photograph (Figure 4) a correlation may be observed with a very sharply defined rectilinear feature that looks like a stone structure that has subsequently become degraded. All four of these elevated building platforms would have to be investigated by excavation to establish their character.
From this it remains unclear whether the verified remains are indicative of a medieval village. An alternative interpretation is that this is the site of a large house and associated farm buildings, which may be medieval or post medieval in origin. However, other places in the central area have geophysical responses that suggest there are extensive spreads of rubble. These might conceal archaeological evidence of earlier buildings. Thus, the presence of earlier medieval farmsteads on the site cannot be ruled out.
World War II
The air photographs, particularly the one in Figure 4, show a cluster of six ring structures in the western end of the field, near Cogley Lane, and two more (Figure 5) on either side the boundary between Crow Close and Carnarvon School playing field at the eastern end. Five of them appear to be superimposed on other, older, features. However, only two at the Cogley Lane end of the field show on the laser survey (Figure 2) and they both give geophysical anomalies. These are magnetic anomalies M1-4 (Figure 14) and resistance anomalies R10 and R11 (Figure 16).
Anomalies M1-3 and R10 define the northern of the two structures, which is consistent with the standard design for searchlight units built in the late 1930s in defensive rings with 12 and 16-mile radii around the major cities in Britain (Osborne, 2004). The unit at Crow Close would have been part of the 12-mile radius ring as well as serving to cover Newton airfield. Each unit had a circular defensive mound up to 60 feet in diameter surrounded by a ditch and a central sunken area up to 20 feet in diameter, within which the searchlight would have been set. The defensive mound was shored up around the sunken area with corrugated iron sheeting, which would explain the positive magnetic anomaly M2. The linear magnetic anomaly M3 is probably a cast iron drainpipe used to keep the sunken area dry after rain. Negative magnetic anomalies M1 and the resistance anomaly R10 define the outer ditch.
The smaller mound to the south is marked as an amorphous magnetic area indicative of ferrous or highly fired material surrounded by an apparently hexagonal or octagonal low resistance linear anomaly, R11, which could be a wall or a ditch. There is no central circular, positive magnetic anomaly similar to the one to the north. The linear magnetic anomaly, M4, which runs into this circular structure could be caused by buried corrugated iron sheeting and mark the site of a slit trench. This smaller, circular structure might have been a gun emplacement, but the local residents interviewed remember both a searchlight unit and Nissen huts on Crow Close during the Second World War, but they do not remember seeing or hearing a gun here.
The area between these two circular structures is characterised by amorphous high resistance features, thought to indicate spreads of rubble or compacted surfaces. There is rectilinear patterning within it. A large rectilinear structure can be seen within this anomalous area to the south east of the searchlight unit, roughly in the area of resistance anomalies R1 and R9, together with a small circular structure just to the west of this. While this area may be the site of one or more of the wartime buildings, it remains possible that it is masking earlier structures.
Three of the circular structures visible near Cogley Lane appear neither on the laser survey nor on the geophysical plots and cannot be explained, though they are thought most likely to be World War II structures. The two circular structures either side of the hedge that marks the boundary between Crow Close and Carnarvon School playing field resemble superficially the structures near the Cogley Lane end of the field and may also have originated in World War II. They were not included within the area covered by the geophysical surveys.
Amorphous areas of high and very high resistance and linear resistance anomalies in the area to the east (Geophysics Area 2) are less easy to interpret. Some of them, such as R17 to 21, could be rubble spreads, but the absence of any signs of World War II structures here on the air photographs suggests that they are more likely to date from an earlier period.