The earliest evidence of human activity in the Yarrows area was found at Oliclate (ND 3015 4522) where a group of late Mesolithic hunter-gatherers had been working flint some time between 4000 and 6000 BC..
Flint working appears to have occurred on a number of natural mounds within the braided structure of the old glacial melt water channel; now the Burn of Swartigill.The mounds, composed of glacial till, were overlaid by thin blanket peat. The basal peat yielded a wide range of radiocarbon (RC) dates consistent with episodes of anthropogenic truncation (peat cutting). Occasional sherds of pottery indicated use of the area during the Bronze Age and continuing into the early medieval period. Roots of Phragmites australis (Common reed), preserved in the peat, indicated that reed beds once colonised the watery areas (1).
Lithic analysis of material from all but one of the mounds indicated blades constituted 40 percent or more of the assemblage, but yielded few microliths considered to be diagnostic of Mesolithic stone tool industries (2).One mound, however, was strikingly different. It was located close to an isolated dome of peat 2.5 m deep, which started to form circa 8600 cal. BP. The dome, of fine fibrous peat, appears to have developed over a pool or spring. Birch preserved in the lower strata indicates the presence of scrub vegetation at circa 8500 cal. BP (1).
The mound yielded over 100 microliths, most of which were backed bladelets but with some scalene triangles. In addition the mound yielded over 60 microburins, a by-product of microlith production from blade-blanks, but very few cores from which the blade-blanks would have been struck. A proportion of the flint had been burnt, all of which was concentrated in one area. No charcoal or other evidence of burning could be found however, neither was there any other evidence of settlement such as food debris, hearths or stake holes.
Most of the lithics were recovered from a natural palaeo-soil approximately 60 to 80 mm deep that extended over a wide area immediately overlying the glacial till and beneath the blanket peat. The stratigraphy within the deposit suggested repeated episodes of use over a long period.
(1) Tipping R 2002 ' Later Mesolithic and Neolithic Landscape Reconstructions at Oliclett
(2) Pannet A 2001 ' Excavation of a Mesolithic Site at Oliclett, Caithness' Cardiff Univ.