Wstępne doniesienie z badań średniowiecznego mostu/grobli w Gieczu koło Środy Wlkp.

With a view of gaining a suitable material for the studies of subaquatic cultural layers, i.e. lacustrine sediments influenced by or deposited under direct or indirect human activity, remains of wooden costruction at Giecz described by B. Kostrzewski (1968) as a medieval dyke were excavated. Tentative studies of subaquatic cultural layers carried out in the vicinity of Ostrów Lednicki - the island with medieval stronghold – schowed out that apart from an archaeological artefact content there were, admittedly, more factors playing a significant role in the case of their characteristic and informative potentialities, from which plant macrofossil remains proved to be of great consequence (Tobolski 1989, Polcyn 1991). For the convenience, a site located on the former lake bed was chosen. During the excavations several cores of sediments were taken for analysis of macrofossil plant remains, pollen, cladocera and minerals. Analysis of wooden construction and strata sequence suggested that the excavated object was functioning at first as a bridge and afterwards as a dyke. For the stratigraphical description of the site the Troels-Smith’s system was applied. On the base of archaeological Ends, pottery and well-preserved sword, the site was dated between the mid 10th and 15th century A.D. Dendrochronological analysis of the bridge/dyke constructions continues.