In the summers of 2011 and 2012 we opened a large trench at the site of Garn Turne in Pembrokeshire. These seasons of excavation at Garn Turne have revealed multiple phases of activity at this site, including the remains of at least two dolmen monuments. Prior to excavation there appeared to be a natural outcrop in the middle of the forecourt. This is very unusual and not paralleled at other dolmen sites in Britain or Ireland. Excavations revealed that this stone is not an outcrop but a quarried stone (named the Floss Stone). It was found to be sitting on the edge of a pit, probably its source, which had evidence of intense burning in one area. A radiocarbon date on short-lived charcoal from this burning event produced a date of 3702-3639 BC. This stone was partly set on a rammed-stone platform which was cut by the digging of a large pit (which we think is the pit for the main capstone at the site) so we can suggest that the quarrying and moving of this stone predates the main dolmen (Garn Turne Major).
Also pre-dating Garn Turne Major is the remains of a smaller dolmen (Garn Turne Minor) situated directly to the north-west of the main site. Prior to excavation only the capstone of Garn Turne Minor was visible above ground. In our trenches, however, we found a number of collapsed orthostats alongside the large prostrate capstone. This monument once stood in a large pit, much like Arthur’s Stone on the Gower. At a later date, and once the monument had collapsed, the dolmen was surrounded by a platform of stones and soil so that the pit and collapsed uprights were no longer visible. We were only able to explore this dolmen in one small area because after the construction of this platform, a series of smaller standing stones were added around the collapsed capstone. Perhaps these were commemorating the dolmen or its collapse.
The main monument at Garn Turne (Garn Turne Major) was constructed after both the quarrying of the Floss Stone and the construction of Garn Turne Minor. A large pit in the forecourt was almost certainly the original location of the 80 tonne capstone for Garn Turne Major. Two radiocarbon dates from burnt hazel placed at the bottom of this pit are 3787-3656 BC and 3761-3643 BC. The capstone was quarried from the ground, flaked into shape using massive hammerstones, and the pit from where it was dug partly backfilled. The massive capstone was then elevated onto its supporting uprights, before collapsing, presumably due to the sheer weight of the capstone. At a later date, a forecourt of sorts was constructed, partly in the remains of the massive quarry pit. Dates from this layer of the pit came back in the late Neolithic/early Bronze Age (2464-2210 BC, and 2618-2470 BC), and we tentatively speculate that these may date the construction of the façade. Another radiocarbon date from higher up in the pit is from the Iron Age (800-547 BC), which along with some iron slag found at the site, suggests that this site saw considerable activity at different points in prehistory. We also identified a series of standing stones in the immediate vicinity of Garn Turne, demonstrating that this entire landscape had seen broader monumental construction.