A rhyolite boulder collected by R. S. Newall in 1924 from an excavation at Stonehenge has been pivotal to arguments concerning glacial versus human transport of the bluestones to Stonehenge. Initial studies suggested that the boulder came from north Wales, and hence was a probable glacial erratic. New petrographic and geochemical analyses however support it being from Craig Rhos-y-Felin in west Wales, the source of much debitage recovered from Stonehenge. Examination of the form and surface features of the boulder provides no evidence for it being erratic. Instead, it is considered to be one more piece of debitage probably derived from a broken-up monolith.