As with the Iron Age period (PKARF Iron Age Chapter), the debate continues over the significance of the upland/lowland divide, as determined by the geological and geographic Highland Fault line. This is complicated by biases in available information. One issue is the identification and survival of sites in the lowlands, where later sites have destroyed earlier remains. Comparison of the RCAHMS surveys of the north-east (1990) and south-east (1994) of Perthshire illustrate this well. A second issue, as outlined in previous chapters, is the bias created by the rest of Perth and Kinross not having seen a similar level of consistent survey as for these two volumes. This is a problem which is exacerbated by the lack of a RCAHMS County Inventory.