_Chamber 1_ Two grids of 1 m x 1 m were set out in the central part of a low but large chamber (length 11 m, width 5 m and height between 1.00 and 1.50 m) containing rich deposits. These were highlighted, on the surface, by a large quantity of dark soils, fragments of pottery and animal bone, situated close to the cavern situated at the end of the entrance corridor of the western arm of the karstic complex. After the cleaning of the loose, potentially disturbed, surface deposits (Context 1) the intact underlying compact deposits (Context 2) were excavated down to bedrock in one of the two quadrants. Considered as a whole, these deposits comprise a homogeneous horizon, 12 to 14 cm thick, heavily and extensively burnt, made up of stones and fine dark grey soil. The deposits produced 119 relatively large fragments of pottery, animal bones, seven obsidian implements, a bivalve seashell that was perforated in order to be used for personal decoration (27 mm long) and a polished red stone (?) bead. The pottery, including the rim of a large container and a number of roundish handles, was made of a clay with a coarse grain. Some fragments had a polished surface, two were decorated with finger impressions. Moreover, three burnt fragments of a medium-thin pottery (6-7 mm thick) were found. Of note among the obsidian artefacts were three arrow heads (25-37 mm long) and a flake, all in original deposition, with very sharp edges (possibly never used). _Internal chamber_ This small chamber extended along the final part of the northern arm of the cavern and was divided into six 1 m x 1 m quadrants. Below the surface deposits (Context 1) disturbed by modern visitors, intact deposits came to light (Context 2) containing an animal bone, 18 fragments of prehistoric pottery (mostly from the same vessel) and micro-faunal remains.

Upper chamber Large, low chamber (11 m long, 5 m wide), containing rich ritual deposits of the Upper Neolithic, Ozieri culture. Context 1: disturbed loose deposit containing stones, animal bones and pottery fragments; Context 2: underlying intact ritual deposit (12 – 24 cm thick), comprising an extensive and heavily burnt horizon, made up of stones, grey ash containing large pottery fragments, animal bones and several obsidian fragments and arrowheads. Radiocarbon dating: • OxA-22197 4942±32 BP (3783-3653 cal BC) • OxA-22198 4997±31 BP (3812-3699 cal BC) • OxA-22199 4935±31 BP (3777-3651 cal BC) Context 6: very hard concretionary horizon (up to 8 cm thick) made up of a combination of calcite, small stones, earth alternating with pottery fragments; Context 5: loose and intact grey-brown deposit (up to 5 cm thick), containing small stones, animal bones, pottery (some of the Ozieri Culture) and obsidian; Context 4: silty cave deposit, orange in colour (6-22 cm thick), containing stones and micro-fauna which seemed to be natural in origin but also contained charcoal fragments. Radiocarbon dating: • SUERC-29318 8160±40 BP (7200-7060 cal BC) Context 3: calcite and bedrock. Lower chamber Semicircular chamber (2.8 m wide and circa 3 m deep), delimited on three sides by large speleothems (rock formations). Context 1: disturbed collapse and surface deposit (10-40 cm thick), containing soil constituted by dark grey ash, goat droppings, large pieces of pottery, animal bones, pieces of wood, an acorn, a match and pieces of plastic; Context 2: deposits of fine, loose, dark grey-brown ash (3.5 cm thick), containing small stones, several bones, a large quantity of pottery and a fragment of metal blade; Context 3: discontinuous calcite formation derived from water percolation (2 cm thick) – no material culture present; Context 4: deposit of black as (thickness unknown), containing very thin soil, some bones and pottery fragments (including the leg of an Ozieri Culture tripod). Large lower chamber Large semicircular chamber (circa 6 m wide and 3 m deep) Context 1: collapse and loose deposit (circa 45 cm thick), containing large stones, soil constituted by grey-brown ash, sheep/goat droppings, wooden sticks and occasional foliage, bones and pottery (including Ozieri Culture) and aluminium; Context 2: loose deposits of soil with ash (circa 5 cm thick), containing occasional rocks, pottery, animal bones, obsidian and a metal nail; Context 3: slightly more compact deposit of grey-brown ash (circa 7 cm thick), containing small stones, animal bones, pottery, obsidian, metal (modern), a bead and a stone figure (Ozieri Culture); Context 4: bedrock. Inner chamber Small chamber along the final part of the northern arm of the grotto. Context 1: surface deposit disturbed by modern visitors; Context 2: intact early Bronze Age deposits containing animal bones, fragments of prehistoric pottery and micro-faunal remains. Radiocarbon dating: • OxA-22619 3755±31 BP (2234-2120 cal BC) • OxA-22620 3683±28 BP (2143-1976 cal BC)

The Grotta Is Janas is a large karstic system containing extensive prehistoric deposits. It is situated in the middle-upper part of a hill slope, above a tributary of the Riu Lareri, at a height of 797 m a.s.l. During August 2011 excavations continued in one of the lower chamber of this grotto: ‘Is Janas Inferiore’. The semicircular chamber (2.8 m long and circa 3 m wide) is situated close to the upper chamber but on a lower level, on one side of a corridor and large chamber connecting the east and west branches of the grotto. It is closed on three sides by large spelothems (cave formations). The central part of the chamber (close to the entrance) was divided into six 1 x 1 m squares (the rear part of the chamber is covered by a collapse). The excavation of this area was not completed but the following contexts were identified: Context 1: collapsed rocks and disturbed surface deposits (10-40 cm deep), dark grey soil with abundant ash, goat dung, large pottery fragments (including some wheel-turned fine-grained orange ware dating to the historic period and some burnt pieces finely decorated with linear and curved incisions which can be ascribed to the Ozieri Culture), animal bone, small fragments of wood, an acorn, a match and some pieces of plastic; Context 2: deposit of loose, fine, dark grey soil and abundant ash (3-5 cm deep) containing small stones (1-5 cm long), some bone and a large quantity of pottery (including a fragment decorated with incised or impressed parallel lines); Context 3: discontinuous natural calcitic formation (2 cm deep), caused by dripping water – no material culture present; Context 4: deposit of dark ash, containing fine soil, some bone and pottery fragments (including a piece with impressed parallel lines and the foot of a tripod 8.8 cm long, belonging to the Ozieri Culture). Only a small part of this context was excavated. Based on the finds it can be said that this deposit is well-sealed by intermediate Context 2 and, therefore, protected from the disturbance seen in Context 1. However, the decorated pottery from Context 4 was similar to that in Context 2, therefore, some disturbance and mixing of the two contexts seems possible. A bone sample from the upper part of the deposit taken in 2010 produced a radiocarbon date of circa 3800-3700 cal B.C., which falls within the late/final Neolithic, Ozieri Culture, as was the pottery from this context.