Dr Traill's paper was divided into four sections: the 1st contained the geology of Andalucia from the Sierra Nevada of Granada to the south; the 2d described the mountain or rock of Gibraltar; the 3d traced the succession of rocks from the Sierra Morena to the south and south-west; and the 4th described the Sulphur Mine near Conil.

1. In the part of the Sierra Nevada visited by Dr Traill, which was at about two-thirds of its height, the only visible rocks were mica-slate, in its lower portions approaching to gneiss, on which reposed beds of limestone, evidently belonging to the same formation as the slate.