An evaluation was commissioned to assess any surviving archaeological remains in advance of a proposed development at Dean's Mill, The Causeway. The evaluation was undertaken in August and September, 1992 and the site code was DM92.

Historical research in advance of the evaluation provided cartographic and documentary evidence that a mill had existed at Dean's Mill since the medieval period until the twentieth century. The evaluation was designed to provide reliable archaeological evidence that would corroborate this historical research. Believed to have been established c. 1100 it is recorded as 'scepeschotesmelne'; in 1347 it was called sheffotes-mill, 1640 called Shaffords Mill. By 18th century it had become Dean's Mill and later Hooker's Mill. It was destroyed in 1954.

The evaluation's main archaeological methodology was the non-destructive stripping of modern levelling and debris deposits that covered the evaluation area. Initially this area was cleared of undergrowth, allowing all upstanding structural remains to be recorded photographically and on plan. This was followed by monitored stripping by mechanical excavation of modern tarmac, demolition debris and topsoil so that the surviving foundations of the mill complex and any other features of archaeological significance could be exposed. Two deep trenches at the same time were also excavated in order to assess the palaeo-environmental aspects of the evaluation: one trench was excavated just south of the northernmost branch of the river Stour, but proved unsuitable for study as it was inundated continually with water from the river. The other trench
(trench A) was located in the south of the cleared part of the proposed development area. This proved to be suitable for palaeo-environmental analysis.

The site strip exposed an extensive range of bonded brick foundation walls and gravel and brick courtyards probably representing the full extent of the mill complex in its latest and final phase. Further investigation revealed that several earlier phases of construction were either incorporated within or covered by this latest phase. Consequently, a detailed brick and mortar survey was undertaken in order to identify these phases. The remaining upstanding structures situated around and over the two mill leats in the north-west part of the survey were included within this survey.

An annotated plan of the mill complex was made, which recorded both the brick and mortar types of individual walls and their chronological and physical relationships. During the course of the demolition of part of the upstanding structures situated between the mill leats, a large mass of bonded brick was removed to a depth of approximately 1.30m. This made a brief study of the deeper stratification possible in that area, which revealed that medieval floors and occupation layers had survived at that depth.

The site strip also exposed wall foundations constructed of brick and mortar of Tudor or Jacobean type in most areas occupied by the later mill and also further to the south. This corroborated cartographic evidence provided by the Doidge plan of Canterbury dated to 1752, which depicted the mill as 'Dean's Mill', but also suggested that the buildings shown on the 1752 plan could have been in existence for much longer than 1752.

Dated key stones in the brick bridge giving access to the site from St Stephen's Road provided a date of 1790 for that bridge's construction. This also provided an approximate date for other examples of this type of brickwork, which being so widespread suggested that a major renovation had taken place. Photographic and other evidence indicated that at least part of an earlier timber-framed building had survived this renovation to be incorporated within the new mill complex.

The next major phase of modification accompanied the introduction of steam, diesel and finally, electric power soon after 1891. In order to accommodate the various engines and other associated machinery, substantial changes were made to the 1790 mill complex. This process of adaption of an essentially late eighteenth-century building continued until the mill was destroyed in 1954.

The deep trench (trench A) excavated on the south of the evaluation area for palaeo-environmental assessment and study exposed a complete and undisturbed stratigraphic sequence. The lowest deposits observed in the bottom of trench A consisted of relatively poorly sorted sandy gravel, with mostly angular flint inclusions. This was interpreted as probably river gravels deposited during the late glacial period (c. 11000-8000 BC). Overlying the basal gravel was a complex series of sediments, associated with two east-west aligned timber structures located in the south of the trench: one consisted of a double row of planks containing irregularly-spaced posts, the other a series of posts, planks and wattle.

The sediments associated with these structures closely resembled sequences already seen in the City of London and known to be related to the Roman and post-Roman waterfronts. The timber structures that were exposed were well preserved and proved to be of Roman and medieval date. The structures identified as Roman in date almost certainly represented the Roman river frontage, which in itself was important evidence for locating the course of the Stour in the Roman period. Ceramic and coin evidence found within the sediments also confirmed that the archaeological sequence was of the Roman and post-Roman periods. The sediments were deposited by river action, man-made activity or by a combination of both processes. The upper sediments sealed the timber structures described above and were considered to have been deposited as a result of river flooding in this area of the Stour.

A group of well-preserved timbers with iron fittings cut this upper sequence of sediments in the north of trench A. Ceramic evidence showed that these timbers were of medieval date and one timber was recovered for analysis. This was interpreted as being either a shutter or gate associated with a medieval mill.

Allen, T. & Bennett, P., 1992, Results of the Archaeological Survey, Dean's Mill, the Causeway. (Excavation archive). SKE30796.

Allen, T. & Bennett, P., 1993, Dean's Mill, The Causeway (Article in serial). SKE30795.