The 2013 investigation inside the grotto del Sambuco took place 22 years after excavations undertaken in the second half of the 1980s. These investigations concentrated on the historical levels and stopped at a hardened paleo-surface that emerged across the entire area, separating the earlier prehistoric levels. This surface was still visible, although partially damaged at the sides by clandestine occupation. Given the short length of this campaign, the excavation began in the eastern part of the trench, where a trial trench dug in 1981 had revealed a paleolithic hearth in the section. The investigation, which made use of an instrument for the spatial location of finds, concentrated on only three quadrants (P15 and Q15 along section 1 and Q16), and revealed two different stratigraphic units: one post-paleolithic and heavily lacunose (US3B), overlying a paleolithic level (US4), that emerged extensively across all three quadrants. The post-paleolithic layer, made up of a moderately compact dark grey clay sediment not easily distinguishable from the underlying US4, emerged in two patches, one of which very small and thin (c. 2-3 cm in depth) in quadrant P15, and a larger patch in quadrant Q16, up to 10 cm in depth. The layer contained rare charcoal flecks and only the occasional pottery fragment, including one with lines of toothed decoration, probably attributable to the bell-beaker horizon. The paleolithic unit was also made up of dark grey clay sediment that was less compact than US3B. It was particularly rich in charcoal especially at the point of contact between quadrants Q15 and Q16, where in the past a trace of a hearth was seen in section 2. This unit produced, 85 lithic finds, mainly from quadrant Q15, both jasper and yellow-orange flint, distributed through the sediment and sometimes at the base of the unit. The types present were backs (PD,LD, fr. PD-LD), scrapers and points. The typology dates the artefacts to the Upper Paleolithic, in particular the late Epigravettian period. The removal of the unit corresponding with the Paleolithic hearth revealed a new stratigraphic unit (US5) across all three quadrants, constituted by a yellowish sandy clay sediment, the roof of which was heavily modified by the erosive action of surface water.

La campagna del 2014 ha ripreso le mosse dalla situazione lasciata alla fine del 2013, chiusa con l’asportazione di lembi residui dell’US3B (quasi certamente Età dei Metalli) e del sottostante US4 del Paleolitico superiore, nei quadrati P15, Q15 e Q16. L’asportazione dell’US4 aveva messo allo scoperto il tetto del sottostante US5, costituito da un sedimento sabbioso argilloso di colore giallastro, interessato da un vistoso fenomeno erosivo, con formazione di canalette e buche di varia forma, facenti parte di una superficie alquanto accidentata, sulla quale si è formata l’unità sedimentaria contenente l’industria del Paleolitico superiore. Già in quella occasione era stata formulata l’ipotesi che la frequentazione paleolitica fosse avvenuta quando questa superficie era in corso di livellamento ad opera di un sedimento argilloso proveniente dall’esterno della cavità; sedimento che non ha impedito, data la sua sottigliezza, il verificarsi di vistosi arrossamenti in molti punti del tetto del sottostante US5 e la combustione di alcune pietre poste al contatto fra le due unità, in seguito all’accensione di fuochi da parte dei frequentatori paleolitici. Obbiettivo centrale della campagna del 2014 è stato quello di allargare lo scavo del livello paleolitico ai quadrati adiacenti, per cogliere in maniera più estesa la morfologia del tetto del sottostante US5. Nel quadrato P16 l’unità US4, costituita dallo stesso sedimento sabbioso argilloso bruno molto costipato, è risultata alquanto sottile, con scarsissima industria litica e abbondante microfauna, certamente proveniente dal sottostante US5, che sappiamo essere ricchissimo di questo materiale. Lo scavo nell’adiacente P17 ha incontrato, al di sopra dell’US4, una nuova unità (US3B), che seppure limitata in estensione, e difficilmente distinguibile sul piano sedimentologico dal sottostante US4, è stata tenuta distinta. Il ritrovamento di due frammenti ceramici, uno dei quali con margini non freschi, al suo interno, indica l’appartenenza ad un orizzonte olocenico. Lungo la sezione 5 fra P16 e P17 uno dei numerosi buchi di palo ( n.10) scavati sia nell’US5 che nell’US4 e chiaramente allineati, era riempito del sedimento del 3B; particolare questo che farebbe pensare ad un legame di questi buchi con l’orizzonte olocenico. Lo scavo dell’US4 nei quadrati P17 e Q17 ha messo in evidenza una morfologia del tetto dell’US5 del tutto simile a quella scoperta negli altri quadrati. Il sedimento continua ad essere argilloso sabbioso per lo più costipato, contenente abbondanti carboni dispersi al suo interno, e scarsa industria litica tra cui alcune microgravettes. Nel P17 il taglio dell’US4 ha messo in evidenza due nuovi buchi di palo, in questo caso appartenenti all’orizzonte paleolitico; nonché alla base dell’unità un breve allineamento circolare di pietre, sulla cui intenzionalità ci sono dei ragionevoli dubbi.

The main objective of the 2015 campaign was to complete the excavation of layer US4 corresponding with the Upper Paleolithic horizon already explored in six quadrants (Q15,R15,Q16, P16, Q17, P17). In 2014, its removal had revealed a paleo-surface with a very complicated morphology (roof of US5), with vertical excavations and rills, as well as clear traces of the combustion of sediments and several stones. This paleo-surface was interpreted as resulting from the large-scale runoff of waters from outside the cavity, in the presence of a surface sloping towards the interior. It was on this paleo-surface, that was in the process of being levelled by clay material carried by the water runoff, that the Paleoliths settled, leaving behind worked stone and a few faunal remains, spread within the stratigraphic layer but with a greater horizontal concentration in quadrants Q15, Q16 and P16. No clear structures relating to the Paleolithic occupation were documented, with the exception of a curved alignment of stones between quadrants P16 and P17. Some of the stones appeared burnt and although there were no traces of charcoal, it is suggested these remains represent traces of a hearth. The excavation of US4 in quadrants Q18 and P18 revealed more of the paleo-surface with the same characteristics, in which there were two post-holes filled by sediment from US 4, certainly datable to the Upper Paleolithic horizon. This horizon has been dated from a charcoal sample taken in 2014 and tested at the CEDAD laboratory in Lecce. The result fell within the full Pleistocene period ( LTL15195A- 13615 +/-75 BP, 14750-14210 BC cal.2s.), in the isotopic 2 stage, probably at the beginning of the Late Glacial Maximum. The typology of the lithic industry seemed attributable to the evolved final Epigravettian period (study ongoing). Once a photo-piano was made of the entire paleo-surface (roof of the underlying US5), excavation of the new layer was carried out in quadrants Q15 and R15. This was constituted by a dark yellowish-brown sandy-clay sediment, without a calcareous skeleton or any lithic finds (the rare finds came from US 4 above), but rich in micro-mammals and to a lesser degree bird remains. The excavation stopped at a new layer, constituted by sediment similar in characteristics to the one above, but compacted and containing calcareous gravel.

The aim of the 2016 campaign was to make an in-depth examination of the deposit underlying US 5 in quadrants R15 and Q15. This contained no archaeological material (lithics or macro-fauna associated with human occupation), but was very rich in micro mammals that are certainly Pleistocenic, given the position of US 5 below the Palaeolithic horizon, dated to 13615±75 BP. The trench, limited to these two quadrants for logistical reasons (the abundance of micro mammals and therefore the substantial time required for sorting), aimed to investigate the layer underlying US 5, which in the small _sondage_ dug in 1981 had produced macro faunal remains of wolf, deer and ox, probably relating to human occupation. In R15, at the roof of US 6, a new layer US6Ø was exposed. Constituted by a blackish sandy clay sediment, about 15 cm thick in section 6, which produced other osteological materials, in particular two fragmentary wolf jaw bones, of the type found in 1981, in addition to a few micro faunal remains. The underlying US6 was constituted by a sandy clay sediment with a skeleton of travertine fragments and micro limestone cobbles, whose variable thickness reached 40 cm in section 1. Lacking any internal sedimentological changes it was excavated in spits (only from t.1-3 to t.4-5 in quadrant Q15 and from t.1-3 to t.7-8 in R15, where underlying US7 was reached. US 6 contained an exceptional quantity of micro mammals, particularly in the first spits (c. 738 g in t. 1-3 in the two quadrants equal to c. 37,000 fragments. The layer also produced the remains of micro fauna, in both the upper and lower parts, the remains of birds, small fragments of marine bivalves and gastropods, some of the latter intact examples of the _Bittium_ _reticulatum_ type, and charcoal fragments dispersed throughout the sediment. Traces of small lithics were also present, including an intact marginal back blade found low down in quadrant R15. The nature of the sediment (predominantly clay and without internal structures and the constant presence of micro cobblestones that certainly came from outside the cave) and the distribution of the macro fauna within it, suggest it was accumulated here by surface water in this point of the cave. However, the build up of this accumulation would have damaged the nearby archaeological level, causing the removal of macro-fauna, charcoal, marine shells, and lithic industry. For the moment this is just a working hypothesis, which needs to be checked during the next campaign, with an in depth excavation a few metres away in the area of the main trench, where it is thought an intact archaeological level may be present below US 5. C14 dating to be carried out on the charcoal samples will ascertain the chronological position of this new horizon.

This short campaign aimed to investigate the deposit underlying US 4 in quadrant Q18, and retrace, beyond the sterile US 5, the underlying US 6. In 2016, the latter, in quadrant R 15, had produced evidence of very ancient human occupation, in the form of malaco-fauna, abundant charcoal, occasional remains of lithic industry and fragments of marine malaco-fauna belonging to bivalves and intact gastropods (_Bittium_ _reticolatum_). Recent radiometric dating of the charcoal gave a date of 23632±150 BP, the end of isotopic stage 3, in cultural terms a moment in the Gravettian period. The nature of US 6 in this quadrant, constituted by a brown sandy-clay silt, containing abundant calcareous-travertine skeleton and small cobblestones of very uncertain provenance, had suggested the accumulation of surface water in this part of the cavern at some point. However, such an accumulation would have occurred to the detriment of the nearby archaeological level, removing the macro-fauna, charcoal, seashells, and lithic industry. This observation led to the need to investigate another quadrant situated 2 m away, in search of the same level but without the phenomena of surface runoff. The cleaning of the top of US 5 in quadrant Q 18 revealed the presence of residual patches of overlying US 4, whose colour and compactness were wrongly held to be part of US 5. The presence of a small amount of lithic industry and sparse charcoal confirmed the attribution of this context. In the central part of the quadrant, there was a post-hole with a conical longitudinal profile filled with residual US 4, which went down into underlying US 5. This confirmed, together with other evidence, the presence of probable shelters in the Epigravettian level. The removal of the residual patches of US 4 revealed a yellowish sandy clay sediment, which in effect corresponded with US 5 identified in other quadrants. However, during the excavation it was seen to be contaminated by elements from overlying US 4, such as charcoal, particularly in the zone close to section 2, where they probably formed two distinct layers, and scarce lithic industry (identified as from the top of US 5). It is likely that this was the initial phase of the Epigravettian occupation (US 4), corresponding with the date 13615±75 BP, or a slightly earlier date that may be verified with new radiometric dating. At the end of this transition phase, the actual top of US 5 appeared, on which neither charcoal or lithic industry were present. The excavations halted here.