The gradients of the Main Post-glacial and Main Buried shorelines are compared over a distance of 37 km in the Forth valley. The High Buried Shoreline, which occurs in a small part of the area, is also considered. The Main Post-glacial Shoreline has been accurately levelled at 231 points, the Main Buried Shoreline at 132 points and the High Buried Shoreline at 50 points. These measurements show that the two extensive shorelines slope in three areas and are horizontal in the two intervening areas, the Main Buried Shoreline also being dislocated in two localities (by I m and nearly I-5 m respectively). During a period of about 2500-3000 years in early post-glacial times the area was uplifted without detectable tilting, but the two dislocations were produced. Subsequently, three parts of the area have been tilted but in two other parts uplift without tilting has continued. The evidence presented shows that the widely used working hypothesis that raised shorelines in areas of glacial rebound have uniform or gradually changing gradients is not of universal application. THE possibility that raised shorelines in areas affected by glacial isostasy may not possess uniform or gradually changing gradients has long been recognized. However, no shoreline diagrams relating to parts of the British Isles illustrate this possibility. In Scandinavia the idea has received considerable attention and M. Sauramo in particular (e.g., 1958) identified raised shorelines with marked changes in gradient. More recently, M. Harme, referring to lateand post-glacial uplift in Fennoscandia, wrote: 'It is most likely that the uplift of the crystalline Precambrian area does not take place as bending, but as block movements' (1964, p. 31). On the other hand, E. Hyyppi, referring to Sauramo's dislocated shorelines wrote: 'This conception of Sauramo's has not been supported by the stratigraphic studies carried out in Finland any more than in Sweden. Not having been able to get anywhere with Sauramo's hypothesis, I have been obliged to disregard it in arriving at a new synthetic relation diagram in the light of my own research material concerning the late-Quaternary history of the Baltic Sea' (1964, p. 37). Like Hyyppa, most other Scandinavian workers have interpreted raised shorelines as having uniform or gently changing gradients and it seems fair to say that the alternative hypothesis is regarded as unproven (e.g., J. J. Donner, 1964, 1966). The present investigation was therefore undertaken to test this alternative hypothesis by detailed work in the western part of the Forth valley in central Scotland, where the writer has for some time suspected it might be applicable. It is suggested that the results of the present investigation show conclusively that the raised shorelines of this area do not have uniform or gently changing gradients. The area investigated lies south of the River Forth and extends from a point about 5 km north of Falkirk to the western limit of raised marine and estuarine deposits near