In the thirty-mile stretch of the valley of the Tay, between its exit from Loch Tay and its entry into the more low-lying regions near Dunkeld, is a remarkable concentration of prehistoric monuments (fig. 1) which can be matched in Scotland only in the Crinan district of Argyll. The majority of sites lie on the flood plain and alluvial gravels of the valley floor, and comprise a series of standing stones, stone circles and round barrows. Until recently, little field work or excavation had been carried out on these sites, although all appeared to be characteristic of monuments of the second millennium B.C. The barrows in particular were of interest in that they appear superficially to be of earthen construction and form a distinctive group of monuments largely confined to this area. Although several had been disturbed, none had been excavated. The majority of them are tree-covered, or had originally supported trees, and many are of very great size, up to 130 feet in diameter and 30 feet in height. In an attempt to ascertain the date and cultural affinities of this group, it was decided to excavate one of these sites in 1964. The site selected was at Pitnacree, five miles east of Aberfeldy (Nat. Grid Reference NN928533). Although the barrow was covered by trees, their arrangement made it possible to excavate a considerable portion of the site, and the comparatively small size of the mound allowed a fairly full excavation. During the six-week season of excavation, a survey of analogous barrows, standing stones and stone circles in Strathtay was carried out. Details of these sites will be found in Appendix I.