The pothole in the Filo Quarry, which came to light by chance during quarrying at the end of the 1950s consisted of a shaft, initially 11 m deep, which proceeded to the north-west in a small cavern. The deposit filling the cavern was excavated in 1966 by the Italian Institute of Speleology. It comprised three main formations separated by marked stratigraphic inconsistencies. The fill contained an important assemblage of faunal remains (over 10 species) relating to the final phases of the Wűrm period (Pasini 1968). The complete demolition of the upper part of the deposit by the quarrying activity and several contradictions in the interpretation of the data from the first excavations have prevented the establishment of a chronology for the deposit, which in the light of present and still provisional knowledge correlates to isotopic stages 3 and 2. The new research, whose main objective was to document the remaining lower stratigraphic levels, uncovered two distinct strata of clay silt (U.S. 99/U.S. 100) in the NE cavity of the impluvium which contained fossils relating to small rodents and large mammals. The new investigations recovered 49 new fossils and identified the remains of wolf, Canis lupus, bison of the steppe, Bison priscus and megaceros, Megaloceros giganteus and gathered taphonomic and geological data. (MiBAC)

The excavation concentrated on the zones identified as “area 1” (zone A and zone B) and the north-east cavity of the karstic structure which showed a high density of finds during the survey undertaken the previous year. A large quantity of skeletal remains was recovered in this area from adult and young examples of _Bison priscus_ (fragments of cranium, vertebrae, ribs, radius-ulna, carpals, metacarpals, coxae, femurs, tarsals). The complex spatial disposition of the bones, which overlay each other in a jumbled manner and were often touching, required a delicate intervention to remove them. The inclination of the longitudinal axis of the zeugopodial, stilopodial and metapodial bones, with respect to the horizontal, varied greatly. Many presented an inclination of circa 30°-35° (femur 08.152, humerus 08.153, radius 08.164), whilst others were in a sub-horizontal (coxae 08.094 and 08.185)or sub-vertical (coxa 08.200) position. Of particular interest the discovery in the north-east cavity of a calcareous layer 4-5 cm thick that was probably the basal alabastrine crust mentioned by Pasini (1968). According to Pasini the alabastrine crust was situated at the base of the sinkhole. The distal troclea of femur 08.152 was resting on the calcareous layer and the rib 08.188 was partially incorporated into the limestone above the crust. The spatial position of the finds in the north-east cavity was documented using measurements taken from three fixed points, two of which were already inserted in the plans made during the previous year. Some remains bore teeth marks left by large predators (probably wolf), whilst on others fractures were visible that were caused when the animals fell into the sinkhole. The extremities of the long bones showed signs of having been gnawed by carnivores. During the excavation of the sinkhole 220 finds were recovered, 72 of which were cranium and mandible fragments from small rodents and 3 were from birds. A further 86 fossil remains were found in the sieved sediments from the wall area 1b (from n. 08.001v to n. 08.086v), all from rodents (hemimandibles and isolated molars) apart from find n. 08.025v (insect hemimandible), ns. 08.076v and 08.087v (chiropteran hemi-mandibles) and n. 08.018v (reptile teeth).

Following the recovery of a conspicuous number of bone finds during the previous three campaigns, the 2009 campaign, as well as continuing investigations in the area known as the “NE cavity”, also focused on sampling material suitable for C14 radiocarbon dating and on documenting the geomorphology of the area. The reopening of this area led to the recovery of a large number of new finds, of particular interest for their very good state of preservation and the scientific importance of the species to which they belonged. Of note the find of a bison neuro-cranium (n. 09.029) of notable dimensions and of other remains close to or in direct contact with the cranium and in close proximity to the alabastrine crust discovered in the previous year. A first phalanx of the bison (n. 09.066), found under the neuro-cranium, will be used for C14 dating. A complete cranium of microtinus (n. 09.067) was resting on the occipital bone of the bison neuro-cranium. Moreover, the recovery of a radius (n. 09.050) and metapodial (n. 09.049) of _Hyaenidae_ was of great importance. This is the first example of remains from this species found in the fossiliferous deposits of Cava di Fila, and one of the few recovered in Emilia Romagna. The presence of the hyena, as well as the wolf, explains the presence of heavily gnawed bones. A complete hare skeleton, still perfectly articulated, was found in area 1 zone B, the only complete skeleton recovered from this deposit since new excavations began in 2006. The position of some of the finds (bison neuro-cranium n. 09.029, II phalanx of bison n. 09.065, II phalanx of bison n. 09.066, skeleton of lagomorph n. 09.061, sacrum of bison n. 09.069, sacrum of bison n. 09.080, femur fragment n. 09.081) was documented using a total station and inserted into the topographic plan of the area. A number of finds from the NE cavity were in a sub-vertical position, with the inclination of the longitudinal axis of the bones, with respect to horizontal, of 70-80 degrees (tibia n. 09.032, neuro-cranium with protrusions n. 09.029, coxa n. 09.033).

The 2010 excavation concentrated on the part of the deposit denominated “incavo NE” where, in previous years numerous finds have been recovered, of great interest for their very good state of preservation and for the scientific importance of their taxonomy. The excavation was deepened, through progressive cuts, in order to examine the Pleistocenic sediment present, of the silty-clay type (in continuation with US 100 discovered in previous years). This was mainly light beige-brown in colour, with abundant inclusions and whitish variegation of chalky origin. The digging also exposed the erosive chalky lines and pockets of this portion of the cavity whose “funnel-shaped” walls characterised by sub-vertical grooves, prelude, in this specific sector, the stratigraphic sequence closing the deposit, which has yet to be reached. The osteological fossil remains, which lay one on top of another in positions determined by active erosive processes, were protected with bandages and left in situ. The bones belonged to large and small vertebrates: the bison (Bison Priscus) was the predominant animal in the deposit whilst the presence of micro-mammals (microtini) and birdlife was of particular interest as few were present in the fossil deposit examined by earlier excavations (Pasini G. 1968-1969). At the same time a fragment of a phalange from a Bison Priscus (Gr. -32576) situated below find 09.029 was removed. At the Centre for Isotope Research at the university of Groninger 8 grams of collagen were extracted from the bone and subjected to C14 dating which gave the following result: 20050 100 BP. All of the sediment removed during the excavation will be wet sieved and coarse sieved for micro-vertebrate and plant remains which are of great importance for the paleo-environmental study. The sediment to be coarse sieved will be treated with a surface-active solution. Sediment samples will be used for various types, including palinological, of analyses.

This year, a trench was opened on a north-south alignment (trench 2011/A) in the “Cavità Galleria NS” measuring about 5 x 3 m and at a depth of 130 cm from ground level. The stratigraphic sequence visible in the wall of trench 2011/A was made up of a series of disturbed layers (US200/201) and a compact layer of brown silty clay, variegated with grey and red, called US 100 (US 100, 101, 102, 103). An outcrop of gypsum emerged in the bottom of the trench, which is probably situated close to the base of the Cavità Galleria NS. A considerable number of fossilized bones were found towards the bottom of trench 2011/A, in US 102. These included the tibia and radius (nos. 11,064 and 11,065) of a bison, the cranium and a molar of a megaceros (nos. 11,071 and 11,072). The context had clearly been disturbed during the excavations undertaken in the 1960s and 70s. At the same time a series of sediment samples, for the extraction of fossil pollen, were taken along the south side of trench 2011/A. During the first week of geo-paleontological research, 123 fossils were collected. The following finds were selected for radiocarbon dating at the University of Groningen Centre for Isotope Research: - First phalange of bison no. 11,077 from US 102, close to the bottom of trench 2011/A, at 270 cm below relative zero (C.G.T.102-11077). - Fragment of bison astragalus no. 11,081 from US 100, close to the west wall of the Cavità Galleria NS, at 140 cm below relative zero (C.G.100-11081). - Bison rib no. 11,100 from US 99 from the base of pozzo Pasini (B.P.P.99-11.100). - Upper molar from a megaceros no. 11,072, from US 201, close to the north wall of trench 2011/A (C.G.201-11072).