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The area discussed is depicted on Sheet 56 of the 1-inch map of the Geological Survey of Scotland. This sheet was geologically surveyed by James Geikie, H. M. Skae, and G. Barrow, and is not accompanied by a Memoir. The district shown in Fig. 1 has received the scantiest notice in geological literature. Fundamentally, its rocks are metamorphosed sediments of the Dalradian Series, invaded by intrusions of various characters and ages. Their apparent sequence, as set forth on Sheet 56 and by Bailey (1925, p. 673, and map opposite p. 698), is as follows:— This table may show the true or the inverted succession (Bailey, 1925, p. 672, footnote). Bailey9s terminology is here adopted. “Basic Older Igneous Rocks” are intercalated with both Ben Lui and Ben Lawers sediments of Glen Shee. Further, the region includes a mass of “Older Granite” which, by invasion of the Ben Lui Schist, produced a complex termed the “Duchray Hill Gneiss”. Sheet 56 shows the gneiss as a band, which is continued on the adjoining Sheets Nos. 55 and 65 (cf. Read, 1928, map on p. 768). In the Memoirs on Sheets 55 and 65 the gneiss is briefly described and reference made to the type area of Duchray Hill (Barrow, 1905, pp. 101–2; 1912, pp. 69–70). Bailey (1925, p. 676) has verified the igneous nature of much of the material exposed on this hill. Read (1927, pp. 337–8) has compared the composite oligoclase-biotite-gneisses of Cromar, in their respect to their origin, with the Duchray |
