This article appeared in the Summer 1973 (Issue #32) edition of the Kent Archaeological Review.
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Rescue Excavations in the Bewl Valley.
Construction is imminent on the dam which will flood the Bewl Valley, south-east of Lamberhurst. Since 1968 the Department of the Environment, through the Society for Post-Medieval Archaeology, has supported excavations to recover evidence of iron-making, which scanty material in the Archives offices at Maidstone and Lewes showed to have been carried on from the mid-16th to the early 18th century.
When operations began, attention was centred on the Forge site at TQ 682 335, close to the line of the proposed dam. The pond which had fed the forge water-wheels had long since been drained, and only faint traces of a dam remained. However, a sizeable ditch ran northwards to join the Bewl. This seemed likely to have been a tail-race, for it began at a patch of wet ground where mole-hills showed scatters of cinder. This proved to be the site, and five seasons' excavation revealed a sequence of some complexity.
The former dam had been levelled about 1800. Material from it had been dumped over the forge site and field drains had been cut, discharging into the tail-races. The overburden protected a complete finery-forge complex, abandoned early in the 18th century. This consisted of a finery hearth, which had been equipped with water-powered bellows, where pig iron had been refined into wrought iron: there had been a hammer, indicated by its base frame, a wheel-pit, and a timber anvil-base set in a pit 7 feet deep; thirdly there was the chafery hearth, used to re-heat the iron during hammering. The chafery bellows had also been water-powered and part of the wheel survived. This group of equipment (Figure 1) had been rebuilt from time to time, but in the general form excavated it appeared to date back to the early part of the 17th century. There was an excellent deposit of metalwork which suggested the manufacture of tools and cutlery, as well as simple refining.
There were two earlier periods. A wheel-pit, which had probably housed two wheels on a common shaft lay beneath the late hammer-wheel-pit, and had probably served a similar purpose, operating a hammer in much the same position. This pit was associated with 16th century pottery and could well correspond with a reference to Chingley Forge being at work in 1588. There was no firm evidence for finery or chafery hearths of this period, although it was just conceivable that the excavated finery could have originated in the 16th century.
The earliest deposits lay beneath the 16th century structure. These were of the 14th century, in the period of bloomery rather than blast-furnace smelting. These consisted, again, of a wheel pit, with part of a wheel remaining, and massive well-preserved timbers providing a base frame for heavy equipment. This was probably again a hammer base, for there were finds indicating smithing, such as scrap, knife blades, and forge cinder. The absence of tap-slag suggested that the actual smelting of blooms of iron had taken place elsewhere. This level produced an interesting group of pottery, particularly as the local medieval ceramics have been relatively neglected. The unglazed wares were similar though not identical to the products of the Limpsfield kilns, whose excavation is, regrettably, still unpublished. Material from Rye was present among the glazed sherds. At the time of writing there is no known documentary evidence for a 14th century site in the Valley, but the excavation serves as a focus for new work among the archives.
The other site in the Valley was the blast furnace at TQ 684 327 (Figure 2). There was slight documentary guidance for this: it supplied plates of cast iron to Robertsbridge Forge in 1566 and it was operating in 1574. However in 1588 it was derelict and although re-leased with surrounding woods in 1590, it is not clear whether the furnace itself was operated again. Here the indications on the ground were clear; the dam survived, breached by the present line of the Bewl, the adjacent wood is named Furnace Pit Shaw, and slag was obvious in the copse below the dam.
Again there were problems with water, for the furnace had been built on a platform cut into the valley side, and had tapped several springs. Again, however, there was the bonus of well-preserved timberwork below the water-table. Indeed this furnace has given us the best guidance to date of the equipment in use in the mid-16th century, more complete than at Panningridge, Sussex (see Post Medieval Archaeology VI (1972)). This was particularly the case with the bellows, for much of the camshaft and its end bearing, the sub-frame and supports, and pivot posts survived. A segment of the overshot water-wheel was in situ in a well-preserved race. There were, indications of the foundations for the trough across the top of the dam and of the penstock supports; and the wooden tail-race, culverted beneath the casting floor, was undamaged. Parts of the structure of the furnace survived to 4 feet in height, and for the first time a section of a 16th century furnace hearth lining could be recorded.
The finds confirmed the dating given by the documents. There was no pottery which would suggest operation after the time of the latest reference, and most material belonged, to the mid-16th century.
The excavations provided keys for future work. The 14th century levels at the Forge prompt the question as to whether medieval hammer forges commonly operated remote from bloomeries. The Furnace excavation amplifies the Panningridge results, and together they form a yardstick for future excavations, particularly for comparison with the period 1590-1650, as yet neglected. The forge showed how much else might be done at a refining site which, in this case, seems to have made a wide range of iron artifacts.