ICHNOLOGICAL AND PALEOENVIRONMENTAL ANALYSIS OF THE PUNTA SAN ANDRÉS ALLOFORMATION (PLIO-PLEISTOCENE), BUENOS AIRES PROVINCE, ARGENTINA. Late Cenozoic deposits that crop-out in the costal cliffs of Buenos Aires Province, have been the center of paleontological studies since the beginnings of the twentieth century. The presence of structures related to biological activity in these deposits has been pointed out by several authors. However, they have never been studied in a holistic way, taking into account all of the structures and not only those related to a single group. Amongst the diversity of trace fossils related to invertebrate activity, burrows are the most abundant and two different morphologies can be recognized: (1) unwalled meniscate burrows referred to Taenidium serpentinum, and (2) walled meniscate burrows interpreted as Beaconites coronus. Other trace fossils found in these paleosols are spherical chambers assigned to Castrichnus incolumis. Trace fossils of vertebrate activity are mostly caves. The largest ones are attributed to the activity of Pampatheriidae or Eutatini (Xenarthra, Cingulata) and the smallest ones to the activity of various types of Caviomorpha (Mammalia, Rodentia) including the families Echimyidae, Octodontidae, Cavidae and Chinchillidae. Trace fossils related to flora are root molds and rhizoconcretions. Ichnological analysis allowed some paleoclimatic inferences. The presence of chambers and burrows associated with earthworm activity suggests soils affected by seasonally dry periods. These observations confirm prior paleoclimatic interpretations based on micromorphological study of the paleosols and sedimentological work.