Guide to the Geology of Scotland

abundant actinolite alternating amygdaloidal appears argillaceous augite basalt basin beds Ben Nevis brown calc-spar calcareous Castle chlorite clay clay-slate claystone cliffs clinkstone coal formation coal-field coast colour compact felspar composed conglomerate consists containing covered crystalline crystals dark deposits district east elevation especially extends feet high feet thick felspar felspar porphyry former forms fossils fragments Frith geological Glen gneiss granite gray graywacke green greenstone hills hornblende igneous rocks interior island lake latter lime limestone Loch lower Macculloch masses merate mica mica-slate miles mineral mountains northern numerous occur old red sandstone pitchstone porphyry portion primary principally probably quarried quartz rock red felspar resembling ridge river round sand schistose schists Scotland secondary seen serpentine shale shells shore side sienite similar slate sometimes spar stone strata stratified structure summit surface Trans transition trap rocks tufa valley varieties veins whilst whole yellowish