Santander, February 19th-22nd 2008 - Aranzadi

190
CATHERINE DUPONT
The deposit of Beauvoir-sur-Mer is 1600
metrers long and 20 to 25 metrers wide with a
height that varies between 1 and 2 metrers (Ters
and Viaud 1983). Currently it is 2 km from the seashore
(Fig. 1). The shape of the deposit seems to
correspond to an old waterway, perhaps an
estuary, which is today filled in. In figure 1, we can
see that this deposit is parallel to waterways that
still work. The distance between the archaeological
site and the seashore is linked to anthropic
action. Some dykes have been built in this part of
the seashore to protect this marsh from the inundations.
So the shape and the location of the shell
midden can correspond to the transport of these
oysters by boat. A part of the present village of
Beauvoir-sur-Mer is built on this shell deposit.
A radiocarbon date on oyster discovered inside
the shell midden attributes a part of the deposit
accumulation to between the 11 th and the 14 th century
(900±60 BP, GIF 5702, Ters and Viaud 1983).
The imprecision of the calibration is linked to the
reservoir effect of datation on shells (deltaR of -
260±65: Marchand et al. in press; Two sigma
Ranges, Hughen et al. 2004, Stuiver and Reimer
1993). The second dating element is the construction
of a castle which has been built on the deposit
(Soret 1994). Its initial construction is dated to
the 13 th century. Even if the midden accumulation
began before this date, it is not impossible that it
continued into other areas after the construction of
the castle, so we do not know the total chronological
extension of this accumulation.
Although the middens of Beauvoir-sur-Mer
have not been previously studied, references to
these accumulations exist (Soret 1985, Rousseau
1963, Begouen 1937, Baudoin 1912, Mourain de
Sourdeval 1864, Rivière 1834). All these authors
know Beauvoir-sur-Mer by prospection and not by
excavation. Their interest in this site is linked to the
predominance of the flat oyster Ostrea edulis in the
deposit.
But the site of Beauvoir-sur-Mer is not the only
accumulation composed virtually exclusively of flat
oysters with joined individuals and located at the
limit of old marshes nowadays drained: Bourgneufen-Retz,
Champagné-les-Marais, La rue de
l’industrie (Le Langon) and Saint-Michel-en-L’Herm
(Fig. 1, Dupont and Bougeant 2008, Verger 2005,
Figure 1. Location of oyster deposits referred to the text. (CAD LQuesnel).
MUNIBE Suplemento - Gehigarria 31, 2010
S.C. Aranzadi. Z.E. Donostia/San Sebastián