Palaeoenvironment
The M1 phase (oxygen isotope stage 5a/4) occupation occurs during a period of falling sea levels (c. 60–70 m/200–230 ft below present sea levels and 10–25 km/6.2–16 mi from present coastline) that is arguably colder than during M2. Donax serra, a sand-burrowing white mussel, occurs in the M1 phase suggesting beach conditions in front of the cave. Densities of shell are lowest in this phase (17.5 kg/m3 or 29.5 lb/cu yd) probably because of the distance of the coast from the cave. M2 phase occupations fall within OI 5a with sea levels circa 25 metres (82 ft) lower than present and a coastline less than 5 kilometres (3.1 mi) from the present shore. Intermediate densities of shell occur in M2 (31.8 kg/m3 or 53.6 lb/cu yd). Climatic conditions may have been temperate and warmer than during M1 occupations. The upper part of the M3 phase (CH/CI layers) is a high-density shell midden (68.4 kg/m3 or 115.3 lb/cu yd), suggesting sea levels similar to those of the present. These upper levels arguably fall just after the Eemian period (OI 5d; c. 100 ka. Temperatures were probably 1 to 2 °C (2 to 4 °F) warmer than present with higher sea levels (+3 m or +10 ft). An OSL date of c. 143 ka (OI 6) for a low-density occupation level (layer CJ) in M3 suggests the M3 phase may need further subdivision when more dates are available.
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