Charters Towers, Queensland.

This district, which stands first among the Australian producing areas, affords an interesting example of rich auriferous quartz-reefs in massive crystalline country-rock. Mr. Rands, in the report already cited, says that the richest part of the gold-field lies on the western edge of a large granitic area; the granite varying from a type in which orthoclase, mica and quartz are the essential minerals, with hornblende as an occasional accessory, to a type in which, besides orthoclase and quartz, hornblende is essential and mica occasional. The samples furnished to the writer by Dr. Redmond, of Charters Towers, were, however, all quartz-diorites, with mica in very small proportions, and have been determined by Prof. Ulrich, of the Otago School of Mines, as varieties of tonalite. In the Brilliant and St. George Co.'s mine, from which the samples were taken, this quartz-diorite formed both foot-and hanging wall of a quartz-reef which yielded on assay an average of? oz. 6 dwt. 9 gr. of gold, and 13 dwt. 4 gr. of silver, per ton The samples were taken from a cross-cut 1079 feet from the surface, and show a remarkable similarity, irrespective of distance from the lode, with one exception (a, Table XI.), which was taken but 2 feet from the lode, and carried a vein of auriferous pyrite.

An account of the separation and analysis of various crystal! line silicates from these specimens is given further on, in the section dealing with the analysis of the constituents of crystal line rocks. The results of that inquiry confirm the conclusion drawn from Table XI., that the country-rock contains neither gold nor silver. The exception (a) above noted, was almost certainly due to an impregnation from the neighboring lode.