Quaternary sediments frequently cover the Tertiary, mostly volcanic base of the small Atlantik island of Porto Santo (Madeira Archipelago). Eolianites, i. e. dunes of cross-bedded marine-bioclastic calcarenite, up to 50 m thick, contain land-snails (list V). The sand was blown out from the large shelf of the island fallen dry during glacial times. Therefore the eolianites are of glacial age, in accordance with the C14-data of 21,570 and 13,480 B. P. (main Würm). The opposite opinion of Bretz etc. for the Bermudas is shortly discussed. — Soils or soil sediments (brown loam, reddish calcareous soils) allow a 3-fold division of some eolianites. Brown loam is to be found also below the eolianites. Colluvial sediments mantle steep slopes and fill flat depressions. They too contain land-snails and interfinger with the eolianites. Therefore they are also of glacial age. We only found one marine conglomeratic terrace, 0—3 m above sea-level with marine fossils; the C14-age is: ≥ 40,000 B. P., perhaps Tyrrhen III (last Interglacial). — There are 2 valley systems, one rather old, the other young, Würm or Post-Würm). The cliff coast is also young and was formed by wave erosion; velocity of recession perhaps 12 cm/a or less. The climates of the glacial times (with eolianites and colluvium) were cooler than today and presumably dry (i. e. not pluvial). Winds came more from the West than now. The upper eolianites are younger Würm but the age of the older sediments is not yet clear. They could be of Würm or Prä-Würm age.