OCTAHEDRITE. 357 Constituent Parts. According to the experiments of Vauquelin, it is an oxide of titanium. Geognostic and Geographic Situations. It is a rare mineral. In Dauphiny it occurs in veins in primitive rocks along with felspar, axinile, rock-crys tal, and chlorite : it lias also been met with in drusy ca vities in transition limestone in Hadeland in Norway. ORDER IX.