At one time many hillsides of Skye now under peat were populated by the early proto-farmers of the Neolithic and Bronze Age periods. The climate was sufficiently dry and warm for peat not to form. This changed, and effectively terminated what we call the Bronze Age, when there was a massive eruption of an Icelandic volcano called Heckla. Ash blasted into the upper atmosphere encircled the Earth and caused a mini "nuclear" winter -- attenuating the sun's warming effect and initiating increased rainfall. The ensuing conditions were perfect for the ecology of the ombrotrophic mire. In glacial rock depressions rainwater gathered to form shallow still-water lakes, and the process of peat formation began.

Because these bogs held water the hill dwellers found their land increasingly water-logged and their crops prone to disease and failure. As a result there was a general move to lower, dryer pastures, or to new pastures entirely. In one or two locations on Skye it's possible to see old stane dykes which disappear into an area of peat bog and reappear, following the same line at the other side. That is clear evidence of Bronze Age toil.

In passing it's also worth considering the shielings which dot the hillsides above the townships of Skye. Shielings were primitive stone shelters where the daughters and sons of communities could rest, or stay overnight, when tending cattle grazing high on the hills. Some archaeologists now believe that many of these were built on the sites of (and most likely using materials from) those original Bronze Age dwellings.

The Heckla eruption was identified, in the course of mainland archaeological digs, by traces of tiny volcanic glass dust, or tephra, found under the lowest peat layer. Every volcanic eruption produces its own fingerprint of these glass fragments. Subsequent traces of other tephra, identifying other volcanic eruptions, are also found within between peat layers, along with pollens and insect remains, and much more. Thus every metre depth of peat is one thousand years of natural history preserved. Changes in ecology, climate, atmospheric pollution (including metals pollution) and archaeology can all be observed from extracted cores.

Just what peat bogs conceal can only be speculated upon. Early field systems, almost certainly, were covered by thousands of years of peat formation. Dwellings too, most likely. The strange scarceness on Skye of standing stones and the almost non-existence of stone circles may be down to peat. It should be noted that more than four metres of peat had to be removed to fully reveal the standing stones of Callanish on Lewis, so arrangements of smaller stones or fallen stones may well be concealed on Skye.

Courtesy of Geoff Holman