While I was engaged on the geological survey of the Postmasburg manganese fields during 1927 the rare mineral zunyite, a basic orthosilicate of aluminium, was discovered in some altered highly aluminous shales or flagstones. The only occurrence of zunyite so far known is in Colorado, where, according to Dana's ‘System of Mineralogy’, it was found at the Zuñi mine, Anvil Mountain, San Juan Co., and near Red Mountain, Ouray Co.

The mineral now briefly described occurs as a rare constituent of the zone of hybrid rocks formed by assimilation of limestone by the dolerite intrusion at Scawt Hill, Co. Antrim. It is found particularly in intimate association with the melilite-bearing types of this hybrid zone and is a constituent of some of the late-formed vesicles in these rocks. The minerals associated with it in the vesicles are chiefly calcite, thomsonite, and another zeolitic mineral as yet undetermined. These vesicles are most frequently enclosed by a ground rich in melilite, or they may occur within large crystals of melilite. In some cases the mineral forms minute venules cutting through the melilite, suggesting that it is derived in part by attack of residual solutions upon the melilite itself. All the evidence clearly indicates that the mineral is among the latest products of consolidation of the hybrid zone.

The orientation of the ‘rhombic section’, the composition-plane of the pericline twin, in the plagioclase felspars as an index of the chemical composition of the felspar waJ first utilized by G. yore Rath, who measured the gngle a on the face (010) between the trace of the composition-plane and the edge [010,001]. Duparc and Reinhard, in their comprehensive work on the determination of the plagioclases, quote two series of values for this angle, one due to Wiilfmg and the other to Becke. They comment on the discordance between the two series, most marked at the acid end, and add that they did not then possess suitable material for critical determinations on their own account. Wülfing's values are given in the form of a curve based on data assembled by Schmidt, and those of Becke were first given in a paper on the felspars in crystalline schists.

About two years ago an aboriginal at Alice Springs in Central Australia reported that at a spot near the western extremity of the McDonnell Ranges the earth, if thrown upon a camp fire, did not extinguish the flames, but on the contrary increased the blaze. To those who heard the story this suggested the occurrence of oil, and it was decided to make some investigations. With the assistance of the native the spot was visited and located on the map. A sample of a white substance, which stimulated the burning of faggots, was forwarded to Adelaide University for examination and proved to be potassium nitrate. As a consequence Mr. C. T. Madigan, B.E., M.A., and myself paid a visit of inspection to the locality.