67 NOTES ON THE GEOLOGY OF THK MT. FLINDERS AND FASSIFERN DISTRICTS, QUEENSLAND. Bv IT. I. Jensen, D.Sc, formerly Linnean Macleay Fellow of the Society in Geology. (Plates i.-vi.) ]Mount Flinders is a rugged peak attaining an altitude of 2,240 feec, and situated about 11 or 12 miles S.S.E. of the town of Ipswich, Queensland. Surrounding the main peak there are a number of smaller cones and rugged rooks, most of which repre-sent remnants of former parasitic vents or smaller foci of eruption which encircled the large volcano. The rocks composing the main peak are felspar-porphyry, trachyte, trachyte-breccia, tuffs, and occasionally a little andesite, dacite, and dacite-breccia. The smaller conos consist likewise of trachyte-breccia and andesite, and some of the most rugged rocks (see fig 8) consist of a plug of trachyte or trachy-rhyolite. The andesite is not by any means abundant, and may be looked upon as merely a more basic phase of the trachyte. It occurs here an'd there interbedded with or overlying trachyte-flows or sheets of breccia. It is noteworthy that the conical mountains are usually com-posed of breccia, with more or less of basic trachyte, dacite and andesite; and, further, they are characterised by better soil (usually of a red or brown colour), and a thicker vegetation; patches of vine-scrubs occur on them. The Physiograpeiy of the surrounding Region. To the north of Mount Flinders lies the Coalfield area of Ipswich and Bundamba, which has been described in a Report by ]\lr. W. E. Camf^ron, B A.* This area forms part of a series of * Geology of the West More ton or Ipswich Coalfield. Geol. Surv. of ^^ueeasland, Rep. 1899.
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