Reasons for Designation
Dartmoor is the largest expanse of open moorland in southern Britain and,
because of exceptional conditions of preservation, it is also one of the most
complete examples of an upland relict landscape in the whole country. The
great wealth and diversity of archaeological remains provide direct evidence
for human exploitation of the Moor from the early prehistoric period onwards.
The well-preserved and often visible relationship between settlement sites,
major land boundaries, trackways, ceremonial and funerary monuments as well as
later industrial remains, gives significant insights into successive changes
in the pattern of land use through time.
On Dartmoor, tin streamworks represent intermittent tin working activity
dating from the medieval period to the 20th century. During this time
previously abandoned works were often brought back into production, while some
streamworks are still not exhausted, raising the possibility that they may
become viable once again.
Streamworks exploited tin deposits that had been detached from the parent lode
and redeposited by streams and rivers within either alluvial deposits in
valley bottoms or in eluvial deposits in shallow, steeper tributaries on
hillsides. The technique involved large scale extraction (which has left major
earthworks visible in the landscape) and the use of water to separate tin from
the lighter clays and silts which contained it. The water derived either from
canalised streams or reservoirs fed by specially constructed leats which can
be seen running for several miles along the contours of many hillsides. The
streamworks themselves survive as a series of spoil dumps, channels and
disused work areas which indicate their character and development.
Streamworking was particularly prevalent on Dartmoor, being by far the most
numerous and extensive type of tinwork on the moor. Remains are to be found in
most valley bottoms and on many hillsides, where they make a dominant
contribution to landscape character as well as providing unusually detailed
evidence for medieval industry. Streamworks on Dartmoor will be considered for
scheduling where they are well preserved and representative of the industry in
this area, or where there is a demonstrable relationship with medieval and
later settlement and its associated remains.
The alluvial tin streamwork adjacent to the Brim Brook survives very well and
contains important information concerning the developing technology associated
with the exploitation of valley bottom tin deposits. Of particular interest
are the range of visually impressive revetted spoil dumps, which highlight and
graphically illustrate one of the major alluvial extraction methods.
Details
The monument includes an alluvial tin streamwork situated adjacent to the Brim
Brook. The streamwork contains a range of well-preserved earthworks which
suggest multi-phase exploitation of the tin deposits. Most of the waste dumps
generated during streamworking lie at right angles to the valley bottom and
many of them are revetted by drystone walling on their northern sides, facing
upstream.
Three discrete blocks of this type of streamwork are visible and each is
served by a well-preserved leat. Within the northern part of the monument
there are a small number of relatively narrow banks lying parallel with the
river and these may represent dumps of more recent origin.
Within the streamwork there are three rectangular buildings used by the
tinners for shelter and storage. All of these buildings have been cut into
earlier waste dumps. The northernmost building measures, internally, 5.2m long
by 3.2m wide, is defined by a 1.5m wide drystone wall standing up to 1.3m high
and is subdivided into two rooms. The interior of the central building
measures 4.8m long by 2.1m wide and the surrounding 1.9m wide drystone wall is
up to 1.1m high. The southern building is much larger than the others, with
internal dimensions of 8.6m long by 3.5m wide.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
It includes a 2 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.
