An urgent archaeological excavation on the Mendieta area (Sopelana, Biscay province) has evidenced the
presence of lithic industry within an original stratigraphic context of possible lower Palaeolithic age. The
materials containing the lithic industry exhibit stratigraphic and sedimentary features derived from fluvioalluvial
and pedogenic processes. The formation procedures of this open-air site took place under warm
and humid palaeoenvironmental climatic conditions. This characterization supplies an important information
in order to understand the genesis and location of the scarce open-air archaeological sites of lower
Palaeolithic age present in the Cantabrian region