THE QUATERNARY VEGETATIONAL HISTORY OF THE FRENCH PAYS BASQUE

SUMMARY This paper presents macrofossil data and additional pollen analyses from the Quaternary sites previously described in Oldfield (1967). Pollen evidence presented in that paper from Bidart Plage Series B (Bidartian) and Senix Series 1 (Moulignan and Senixian) is amplified and extended by more detailed and comprehensive diagrams. The additional pollen-analytical evidence from the Bidart section confirms the importance of a Castanea-dominated pollen assemblage zone within the Bidartian Interglacial. The new diagram from Senix shows that the Moulignan major biostratigraphic subdivision is likewise interglacial in character. The late-temperate and post-temperate stages of this interglacial are well represented by the Senix and Mouligna Cliff pollen sequences now published. The macrofossil evidence from Bidart Series B(Bidartian), Mouligna Cliff MC3 (Ilbarritzian) and Marbella (Marbellan) is represented on a quantitative basis using large and volumetrically equivalent samples from each level. The main additions to the flora from these macrofossil diagrams are a wide variety aquatic and semi-aquatic species including, for the Bidartian, Ludwigia palnstris and for the Marbellan, Aldrovandra vesiculosa and Proserpinaca cf. palnstris a North American species not previously recorded in Post-Tiglian deposits from Europe. From Bidart, there are also interesting macrofossil records of woody warm temperate taxa, for example Chamaecyparis thyoides, Cotoneaster acuticarpa and Ostrya cf. carpinifolia. The non-aquatic macroflora from Marbella is dominated by Erica species the seeds of which have been identified largely on the basis of the fine detail of their seed coats revealed by Scanning Electron Microscopy (Huckerby, Marchant and Oldfield, 1972). The macrofossil diagram from Marbella gives a detailed picture of the complex hydroseral changes taking place during the late- and post-temperate stages of the interglacial. Along with the stratigraphic and pollen-analytical evidence from the site it allows a rather comprehensive reconstruction of ecological changes taking place around the site in response to factors such as climate and soil deterioration and rising sea-level. Macrofossil records are presented from the early pleistocene Bidart Series A, the oldest material studied. The richness of the narrow peat lens in ericaceous remains strongly supports the inference from the stratigraphic and pollen-analytical record that the site represents the organic part of the ‘A’ Horizon of an acid, wet heath soil profile. Other suites of macrofossil records from Senix, Series 1, and Mouligna Cliff, MC 1 (Moulignan and Senixian), from Chabiague (Chabiaguian) and from Mouligna Plage (mid-Flandrian) are tabulated. Sediment from the coldest totally deforested episodes of each of the major cold phases considered to be contemporary with glaciation at higher latitudes and altitudes, either completely lacks or is exceptionally poor in macroscopic plant remains. At no site are the identified remains incompatible with the ecological interpretation of the apparently deforested intervals advanced on the basis of the pollen-analytical evidence (Oldfield, 1967). The macroflora from the Artemisia-rich, supposedly cool, dry episodes of low but not minimal tree pollen-representation, such as Ilbarritzian III includes open ground species of southern (e.g. Valeriana tuberosa) as well as northern affinities and tends to support previous suggestions that the flora during such periods was geographically mixed. With the completion of the macrofossil analyses from the sites, it is proposed to publish a final paper summarizing all the Quaternary palaeobotanical evidence from the area and commenting briefly on its general ecological and biogeographical significance.