The enigmatic ‘Newall boulder’ excavated at Stonehenge in 1924: New data and correcting the record

Some authors have questioned whether the bluestone megaliths present at the Stonehenge Neolithic stone circle were transported from their source area in north Pembrokeshire, over 200 km to the west, by ice, rather than humans. There is scant evidence for either hypothesis and much debate on the matter since the 1990s has involved the so-called ‘Newall boulder’, a stone collected in 1924 by Lt-Col Hawley. Initial studies considered the boulder to be a glacial erratic and hence supported the ice transport hypothesis. More recent work discounted this interpretation and proposed that the boulder was a piece of rhyolite debitage, itself derived from a broken-up monolith, most likely Stone 32d, originally sourced from Craig Rhos-y-Felin, in north Pembrokeshire although this has been challenged in a recent study.

This paper aims to clarify the record regarding previous studies on the Newall boulder and samples taken from it for analysis and to correct errors of fact introduced into the current literature. Petrographic, automated SEM-EDS analysis and portable XRF investigation (including new analyses) relating to the characteristics and composition of the Newall boulder are presented, supporting (a) the interpretation that its original source was Craig Rhos-y-Felin, in north Pembrokeshire and (b) that there is no evidence to support an interpretation that it is a glacial erratic. In addition, it is shown that the overall non-sarsen lithological assemblage at Stonehenge is restricted, supporting derivation by human activity from a limited number of sites, predominantly from west Wales, but also NE Scotland, and not derived from glacial erratics.