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III.—The Crystalline Rock Areas of the Piémontese Alps

Published online by Cambridge University Press:  01 May 2009

Extract

In this group, shown in the sketch-plan Fig. 4, may be included the interesting pietre verdi areas (1) of the Rocciavré ridge on the right, (2) of Monte Rocciamelone on the left side of the Dora Riparia Valley, and (3) of the Rocciacorba ridge and the Avigliana belt of spurs where the Dora and the Sangone Rivers emerge from the Alps and enter the Po Valley about 20 kilometres west of Turin.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1916

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References

page 250 note 1 These cascade gullies, varying from 100 to 300 metres in height, are characteristic of the mountain-sides of the Dora Riparia Valley, and are locally called orridi both from their weird, forbidding appearance and the enormous quantities of detritus and débris brought down through them by the torrents when in flood.Google Scholar

page 250 note 2 Boll. R. Com. geol., 1876, p. 108.Google Scholar

page 252 note 1 The gneisses of Bussoleno are among those regarded by Professor Gregory as intrusive and Pliocene (“Waldensian Gneisses”: Q.J.G.S., 1894, p. 232 et seq.). His views were traversed in detail by Franchi, “Appunti Monti di Bussoleno”: Boll. R. Com. geol., 1895, p. 177 et seq., and by Novarese, “Rilevamento Valle Germanasca”: ibid., 1895, p. 277 et seq.; also by Stella, “Valli Orco e Soana”: ibid., 1894, p. 349, footnote.

page 252 note 2 Franchi mentions such crystals up to 20 centimetres in length. Op. cit., 1895, p. 3 et seq.Google Scholar

page 253 note 1 The calc-schist formation extends north-west, and entirely encircles the mica-schist and minute gneiss massif of Rocca d'Ambin (3,377 m.), about 20 by 10 kilometres in length and width, which lies between the upper Dora Riparia Valley on the Italian and the Are Valley on the French side, and at its northern extremity is crossed by the Mont Cenis road from Lanslebourg to Susa.

page 254 note 1 Of this “Morainic Amphitheatre of Rivoli”, Professor Sacco, F. has given an interesting description in Boll. R. Com. geol., 1887, p. 141 et seq.Google Scholar

page 255 note 1 The quarried exposure of lherzolite with euphodite and magnesite is on the south-east slope of Monte Musiné, above Casellette (505 m.). About 8 kilom. east of this point, midway between it and Turin, lies, at Pianezza, in the morainic area, Roc Gastaldi, an erratic monster-block of euphodite measuring 30 by 12 by 14 metres in length, width, and height = 5,000 cubic metres or over 10,000 tons. It is surmounted by a small chapel.Google Scholar