
In 1966 excavations in the Car Park to the north-west of the Monument revealed three substantial pits. The shadows of the substantial posts which these had contained were clearly visible. None of the pits produced any artefacts apart from a single piece of burnt bone and quantities of charcoal. This was identified as Pinus sp., and dated to the Mesolithic (results).
In 1988 a similar pit was discovered further east, although this lacked clear evidence of a post-shadow since it had been recut. However charcoal discovered within this feature also proved to be Pinus sp. and dated to the Mesolithic.
The significance of these features is unclear, althoughat least some of the pits appear to have held substantial timber uprights (which may have been akin to totem poles). The span of the results over 300 - 1600 years indicates the longevity of the activity and analysis of the results suggests that it occurred between 8500-7650 cal BC and 7500-6700 cal BC (see probability distributions).