Fontana Ranuccio: Italy's Earliest Middle Pleistocene Hominid Site

Abstract

by ALDO SEGRE and ANTONIO ASCENZI Istituto Italiano di Paleontologia Umana, Piazza Mincio 2, I-00198 RomelDepartment of Biopathology, "La Sapienza" University of Rome, Policlinico Umberto I, Viale Regina Elena 324, I-00161 Rome, Italy. 9 x 83 After preliminary surveys, investigations have been carried out along the whole of the Sacco-Liri Valley in southern Latium (fig. 1) by the Italian Institute of Human Palaeontology (Biddittu and Cassoli 1968; Biddittu 1972, 1974a, b; Biddittu and Segre 1978). One form this work has taken is that of studying the material made available by the excavation of quarries for the extraction of pozzolana. Such excavation has resulted in a cross-sectioning of the Pleistocene deposits at a higher level. Whole hills have been removed in this way, and field research has had to be adapted to this situation. The supervision and monitoring of excavation has been particularly thorough in the district of Anagni, in the province of Frosinone, where a succession of new cross-sections at close intervals has made possible a three-dimensional stratigraphic reconstruction. In Frosinone, the valley of the Sacco and Liri Rivers displays a succession of buried palaeomorphological basins of pre-Villafranchian eotectonic origin caused and further depressed by transversal fault systems. This graben valley is delimited by Mesozoic to Helvetian limestone horsts 1,500-2,000 m high; by pressing inward against the graben valley, the horsts have produced longitudinal folds which have made the depressed basins more complicated. Seven fluvial or lake basins situated between Anagni and Cassino (Segre, Piperno, and Biddittu 1980)-some of them connected and some isolated-are now filled by Middle Pleistocene sedimentation (Settepassi and Verdel 1965, Segre and Biddittu 1981). Intercalated with these deposits, but only in the Anagni Basin, are peripheric pyroclastic products of the Latian volcano, transported up to 28 km from their source. Especially in the other basins, lying farther southeast, the pyroclastic products of the little fissure volcanoes called the Ernici that lie along the faults in the longitudinal system of the valley are locally incorp'orated into these deposits. The Fontana Ranuccio deposit-the subject of this reportis the upper part of the series of Pleistocene basins farthest northwest of Anagni (Biddittu et al. 1979, Segre 1982a). It is divided by the conjunction of two valleys and is surrounded by hills made up of Helvetian-Tortonian sandstones (fig. 2). The base of the Pleistocene deposit consists of freshwater clays containing Pisidium and Middle Villafranchian yellow sands (v) with a rich variety of fauna, including Anancus arvernensis, Archidiskodon meridionalis, Equus stenonis, Dicerorhinus etruscus, Leptobos sp., Croyzetoceros ramosus, Eucladoceros sp., Cervus philisi, Gazella borbonica, Gazella torticornis, Hyaena sp., Canis etruscus, Canis cf. alopecoides, Macairodontidae sp., and Testudo sp. (Cassoli and Segre Naldini 1982).Above this layer there is a series (m) containing calcareous clay and travertine (below) and limnotufites (above); the latter are the result of the earliest volcanic activity and are associated with silicified conifer remains. Archaic stone pebble artefacts are found in a prevolcanic lime-clay layer (Biddittu and Segre 1980a, Biddittu 1982). In the depressed valleys left by an erosional cycle which cut into formation m, pozzolana (an incandescent pyroclastic flow of nonwelded small scoria and lava fragments) from the Latian volcano (p), was deposited to a depth of about 20 m, levelling much of the previous morphology. The earliest and latest K-Ar datings for the pozzolana (Layers 12 and 13), giving a range of 528,000-487,000 years b.p., were carried out on minute leucites in the form of intercalated thin lenses deposited by direct eruption fall-a characteristic which virtually guarantees the contemporaneity of the leucites with the layer containing them (table 1). The Fontana Ranuccio series (r) was laid down in the shallow basins in which the pozzolana was modelled, and its composition is as follows: 11, palaeosol; 10, tufitic urrent bedded sands; 9, iron duricrusts; 8, clayey limnosol; 7, tephra, a volcanic cinder dust layer from the Ernici volcanoes, with Buxus and Zelkova flora and Cyclostoma elegans; 6, palaeosol archaeological ayer, with a K-Ar dating of 458,000 years b.p.; 5, solifluction and cryoturbated horizon; 4, lapillitephra with a K-Ar dating of 366,000 years b.p.; 3, tufo litoide, a kind of welded ash-flow tuff acies; 2, pedogenized layer; 1, terra rossa palaeosol mostly due to oxidation of pyroclastic piroxenes. The fossil faunal remains, which are very fragmentary (Cassoli and Segre Naldini 1982), lie scattered within Layer 6. The species discovered so far are Macaca florentinus, Palaeoloxodon antiquus, Rhinoceros sp., Hippopotamus cf. anfibius, Sus scrofaferus, Bos primigenius, Bison sp., Equus cf. mosbachensis, Cervidae of Verticornis group, Cervus elaphus, Dama clactoniana, Ursus deningeri, Cuon cf. alpinus, Castorfiber,