BOROLANITE, one of the most remarkable rocks of the British Isles, found on the shores of Loch Borolan in Sutherland shire, after which it has been named. In this locality there is a considerable area of granite rich in red alkali felspar, and passing, by diminution in the amount of its quartz, into quartz-syenites (nordmarkites) and syenites. At the margins of the outcrop patches of nepheline-syenite occur; usually the nepheline is de composed, but occasionally it is well preserved; the other ingre dients of the rock are brown garnet (melanite) and aegirine. The abundance of melanite is very unusual in igneous rocks, though some syenites, leucitophyres, and aegirine-felsites resemble boro lanite in this respect. In places the nepheline-syenite assumes the form of a dark rock with large rounded white spots from to tin. across. In Finland, melanite-bearing nepheline rocks have been found and described as Ijolite. (J. S. F.)