The object of the present short paper is to draw attention to what A seems to the writer to be a rather important omission in most recent discussions of the origin and nature of granite. In these discussions the word granite or almost equally often the word granodiorite are used as if it was to be assumed that all granites are alike and all granodiorites alike. In what follows, for the sake of brevity, all will be called granites, as a general class-name, without discriminating each time on small points of petrographical difference. Now all granites are not alike, by any means. They show wide variations, not so much in their main components of quartz, felspar, and ferro-magnesian minerals (the essential minerals, according to definition), but in their minor constituents and accessory minerals and still more in some of their accompanying phenomena. By this last expression is intended not so much their metamorphic effects, in the narrow sense of the word, but what is commonly called pneumatolysis, and still more importantly, the accompanying ore-deposits, if indeed it is possible to discriminate between these two categories.