In a former paper under the above general title (Quart. Journ. Geol. Soc. vol. xliii. 1887, pp. 457 et seq .), the distribution, so far as it is at present known, of the nepheline-bearing rocks in Brazil was given, together with a somewhat detailed description of the Pocos de Caldas locality. Since that time three important petrographical papers relating to this group of rocks have appeared, one of which is accompanied by a detailed geological description of the insular, and presumably later, eruptive mass of Fernando de Noronha. In this and subsequent papers, it is proposed to treat of the other continental localities, with special reference to the geological relations and mode of occurrence of this interesting group. One of the localities enumerated in that paper—the Serra de Bocaina—should be eliminated from the list, as a recent examination shows it to be composed exclusively of gneiss and granite. The specimens reported to have come from this locality are probably from the neighbouring mass of the Serra de Itatiaia. The peak of Tingua is one of the two prominent masses that break the somewhat monotonous, approximately even-topped out-line of the Serra do Mar, as seen from Rio de Janeiro; the other being the well-known Serra dos Orgões. Of the two, the former, although of less elevation (1600 as compared with 2232 metres), is, to the geological eye at least, the most striking, since its topographical features, and more particularly its conical form and apparent distinctness from the range to which it belongs,