Geobotanical remote sensing techniques have been applied in studies of the geological characteristics of the Assynt area of Sutherland, Scotland. Airborne Thematic Mapper (ATM( data were used to evaluate the geobotanical utility of the multispectral information recorded in the visible and reflected infrared bands with respect to mineral exploration. The main aims of this study were, first, to evaluate remote-sensing techniques for the detection of stressed vegetation due to underlying mineral deposits and, secondly, to study the possibilities of using ATM data for lithology and structural mapping under existing natural conditions. Of the eleven multi-spectral bands, differences in canopy physiognomy characteristics may partially control the spectral response in bands 5, 7 and 9. Band 7 in the near-infrared wavelength region, however, has the contrasting effect of apparently enhancing topography and reducing the spectral effect of vegetation. This permits the recognition of a number of linear features on the band 7 image which may be interpreted in terms of structural geology. Several small-scale previously unrecognized lineaments which run in the NWW-SEE direction parallel to other known basic dykes in Lewisian Gneiss have been recognized. Stressed vegetation near Ledmore, north-west of Loch Borrolan, has been identified.