Estimates suggest that it may have taken as much as 80,000 hours of work to construct the ditch at the Ring of Brodgar, no mean feat given that it was dug with bone and antler tools. As the ditch is formed of short individual stretches work may have taken place over a number of years, but it may also be that different communities were responsible for their own length. The platform inside has been carefully levelled, though it is not horizontal. The erection of each stone required cutting into bedrock to form a socket, which was then filled with packing material to help keep the stone in place. Today, most of the upright stones sit in modern sockets.
Transporting the Stones
Research indicates that the individual stones are likely to have come from several quarries across the Mainland of Orkney. They were perhaps brought by different Neolithic communities to mark their position within the wider farming community of the islands. One such quarry lies at Vestrafiold in the hills to the north of Skara Brae. Another lies near Staneyhill to the east.
The local sandstone fractures naturally into rectangular slabs, but removing a slab suitable for a standing stone would require skill and attention. Transporting that slab across the countryside to the circle would then have required considerable knowledge and a substantial workforce.