For many years past I have been familiar with the Trias of Staffordshire, but of late I have been noticing more carefully, during my occasional visits to that county, the pebbles in the Bunter, in the hope of being able to identify the parent rocks from which they have been derived. It has already been regarded as almost certain that many of them have a northern origin: and with, this idea in view I observed last summer the lithological character of the quartzites near Loch Maree. Although the results at which I have arrived are very incomplete, I think more good will be done by publishing them than by waiting, because, as it seems to me, they settle one or two points of importance, and because a question, like that of the origin of the pebbles in a deposit so widely spread as the Bunter, is one which can be better determined by a number of observers living in different localities than by any one person, especially if, like myself, he has but little time to spare for the investigation. If, however, I can show that one or two points may be regarded as fairly certain, it will very much facilitate the work of such observers. This work, the careful scrutiny of the contents of conglomerates, is one of more importance than may at first sight appear, because a rock fragment no less, and sometimes more, than a fossil records certain facts in the physical geography of the deposit in which it is found.