Excavations at Oldbury Iron Age Hillfort, Ightham 1983
by F.H. Thompson M.C., M.A., F.S.A.
The programme of investigation of the Iron Age Hillforts on the Greensand Ridge of Surrey and Kent was resumed in 1983 with a season of excavation at Oldbury, near Ightham, Kent. Oldbury, with its vast area of 123 acres and dominant position covering the Medway and Darent valley routes to the Thames, demands attention in any scheme for research into the later Iron Age of south-east England.
The Archaeological Background
The first deliberate excavations were those undertaken by the late John Ward-Perkins, F.S.A. in 1938. He examined the defences on the west, the north-east and south entrances, and carried out some exploratory trenching at various points within the interior. He concluded that the hillfort was a "Wealden Culture" stronghold built in the first century A.D., possibly against Belgic expansion. Subsequently, the area fell under Belgic domination and was refortified against the Roman conquest of A.D. 43, to which it succumbed. Post war re-assessment of his chronology suggests that his two-phase occupation should be put back by a hundred years into the first century B.C. Investigation of the Surrey hillforts of Anstiebury, Holmbury and Hascombe in 1972-7 formed a hypothesis that they were a short-lived phenomenon of the first half of the first century B.C., possibly related to Caesar's landings of 55 and 54 B.C. It was followed by excavation at Bigbury, near Canterbury, in 1978-80, when an attempt was made to define archaeologically the beginnings and end of a hillfort historically related to Caesar's second landing of 54 B.C. The intention behind renewed excavation at Oldbury was to see if it would provide an archaeological link between all these sites and define their role more clearly in the period c. 100 B.C. - A.D. 43.
Geophysical Survey
Oldbury presented problems with tree cover and a putative lack of internal occupation, compounded by its very large area. Therefore, as in previous excavations at other hillforts, Dr A.J. Clark kindly spent three days carrying out proton magnetometer surveys. These were largely devoted to the southern half of the hillfort. He also carried out some test scans in the northern half, but the results were not encouraging. However, in the southern half, some thirteen anomalies were noted, some of the readings being encouragingly high.
The completed excavation at Oldbury.
The Excavations
The principle adopted was, as far as possible, to make a direct comparison with the work of 1938, rather than to adopt an independent approach. Thus, a section was dug through the defences 130 feet west of the west inturn of the south entrance. At the request of Kent County Council that the public footpath, which runs along the filled-in main ditch, be kept open, the section was cut in two adjoining but overlapping lengths. The main rampart was largely of dumped sand with a core of heavy rubble, 14 ft. wide and surviving to a height of 4 ft. Two or three massive blocks might conceivably represent the remains of a stone front revetment, and a tumble of further massive blocks in the ditch-fill lends color to this suggestion. The rampart make-up was sterile, but the tail sealed a small hearth which provided a charcoal sample for radiocarbon dating, and slight occupation on the tail yielded a small number of sherds and four slingstones. At the foot of the steep natural slope below the rampart, the inner face of the main ditch was located. The ditch was 12 ft. wide and 5 ft. deep below the present surface. The lowest filling was a tumble of massive sandstone blocks, separated from a second tumble by silt, with further silt layers to the surface. The outer bank was a mass of dumped stony sand, with outward-sloping tip-lines, some 20 ft. wide and a mere 3 ft. high. It was separated by a gap of 20 ft. from the outer ditch, a relatively slight feature 9 ft. wide and 3½ ft. deep below the present surface.
Of the thirteen magnetic anomalies located by the geophysical survey, eleven were investigated, and eight lay on the higher ground at the south end and extended from behind the rampart towards the central track, while three lay further north along the side of a shallow valley. In each group, a single anomaly failed to disclose any archaeological evidence, for reasons yet to be ascertained, but in all the other cases, there was evidence for human activity ranging from slight to unequivocal.
In summary, the larger group produced the following evidence, in an ascending order of significance: anomaly 12, nil; anomaly 4, a little charcoal and pottery; anomaly 5, slight evidence for a hearth; anomaly 8, a well-defined hearth on the tail of the rampart, possibly post-dating the hillfort; anomalies 2, 3, and 13, clearly defined hearths, probably of the hillfort period; anomaly 6, a probable iron-smelting site in close proximity to the rampart. The evidence from the smaller group was as follows: anomaly 14, nil; anomaly 9, hearth; anomaly 11, this high reading was investigated by a 10 ft. square trench, produced pottery at a fairly high level, then a characteristic hearth, and finally a possible gully which yielded a useful pottery group. The results from this last anomaly suggest the possibility of a circular hut with a central hearth, and it is conceivable that other similar hearths may have a similar structural relationship which was not detected because of the smallness of the trenches.
Future Work
It is hoped that further investigations will take place in 1984 of anomaly 11, in a larger area excavation and also the possible iron smelting site of anomaly 6. There is now fairly good evidence for internal occupation, which the excavators of 1938 regarded as doubtful, though the paucity of finds may otherwise support their view that "Oldbury was never permanently occupied". It is also hoped in 1984 to carry out a re-investigation of the defences near the north entrance. It was here that Ward-Perkins found evidence for the re-fortification which he attributed to the Belgae. It would be useful to obtain confirmation of this and to define the chronology more precisely."
