Archaeological work under the guidance of P Jones of SCAU and by N Branch of ArchS focused upon a dry valley (the hollow, as it was formerly described) visited repeatedly by Mesolithic communities that had been identified during previous evaluation at the quarry. The archaeological work consisted of geophysical survey, environmental sampling and excavation and was undertaken by professional, volunteer and student archaeologists. The work took place between June 2005 and February 2006, and led to the identification of widespread evidence, in the form of flint artefacts, hearths, and other activity areas. It is estimated that the total number of struck flints, including that from a buried soil that sealed the Mesolithic stratigraphy, amounts to over 75,000. The work revealed that visits had been paid to the site from the earliest (c 10,000BP) to the very latest (c 5500BP) stage of the Mesolithic, with, perhaps, the most intensive activity during the ‘pioneering’ stage of the later Mesolithic (c 8000–7000BP). In addition to the Mesolithic activities, later features that include several later Bronze Age and Early Iron Age pits were revealed, at least three of which produced complete pots that may contain human cremations. Some of the eleven burnt flint scatters found in the west of the site may also be of later prehistoric date. On the southern side of the site about twenty pits and a hearth of early medieval date were found, and several slightly later field ditches were traced across the site. The latest feature is a loosely constructed causeway largely comprised of Merstham Stone and probably dating to the early post-medieval period. (384, 386, 387, 388, 390)