Excavations were conducted at La Riera to test hypotheses concerning variability among Upper Paleolithic/Mesolithic artifact assemblages and to define and begin to explain changing hunter-gatherer ...adaptations to the coastal region at the end of the Wurm and the beginning of the Holocene. The 36 strata contain assemblages that can be assigned to Aurignacian(?), Solutrean, Magdalenian, Azilian, and Asturian culture-stratigraphic units. However, there is considerable nontraditional variability and great similarity between certain "Solutrean" and "Lower Magdalenian" assemblages. Shifts in raw-material procurement patterns are noted, and the variable lithic-debris fractions reflect changing tool-manufacturing activities. All these indices suggest differing uses of the cave or fundamental alterations in settlement-subsistence systems and cast doubt on the stric validity of the classic "cultural" subdivision scheme for the Stone Age of western Europe. Palynological and sedimentological analyses trace a series of major environmental fluctuations. Interlevel faunal variability may be attributed in some cases to environmental change and in others to changes in subsistence practices or the role of the site. The faunal data indicate increasingly diverse, intensive exploitation of wild food resources throughout the sequence, perhaps the result of regional demographic pressure.
