Allanite has been recorded as occurring in a number of the granites of the North of Scotland, but while engaged on a research on these rocks for another purpose, I have discovered its presence in a number of rocks in which it has not previously been recorded. The granites in which it occurs may be enumerated. They are:—(1) Hildesay granite (Shetland); (2) Lairg, Sutherlandshire; (3) Ben Rinnes (grey); (4) Ben Laoghal, Tongue; (5) Ben Nevis; (6) Peterhead; (7) Loch Roag, Lewis; (8) Kennethmont, Aberdeenshire; (9) Marscow, Skye; and I have quite recently identified it in the granite of (10) Assouan, Egypt. It seems therefore to be fairly widely distributed in granitic rocks generally, and to all appearance indifferently in rocks of basic and acid type. It has previously been recorded as occurring in the first three of the foregoing list, but I am not aware that it has hitherto been observed in any of the others. In Hildesay granite, where it occurs in unterminated prisms in association with epidote, and in which I observed it as long ago as 1900, it oftens forms the cores of the epidote crystals which characterise that granite. Here it is frequently found to be twinned. Exact measurements are difficult if not impossible, owing to the high absorption of the mineral, but the following angles of extinction with the twinning line have been observed—14°, 59°—mean 36½°; 55°, 20°—mean 37½°. With the edge of the prism in another case it was found to be 36°. It