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On the large Porphyritic Crystals of Felspar in certain Basalts of the Isle of Mull

Published online by Cambridge University Press:  14 March 2018

Extract

In the basaltic lavas of Iceland certain porphyritic crystals of unusually large dimensions, occur embedded in the matrix of the rock, and from an early date have received the notice of writers on the geology of that island. Amongst these authors might be mentioned :—Professor Forchhammer, Dr. F.A. Genth, M. A. Damour, Prof. Zirkel, M. P. Schirlitz, and M. R. Bréon.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1889

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References

page 154 note 1 Journal für praktisehe Chemie. Band III. 1843. p. 385.

page 154 note 2 Annalen der Chemie und Pharmacie. B. LXVI. 1848. p. 13.

page 154 note 3 Bulletin de la Société Géologique de France. Tome VII. s. II. 1850. p. 83.

page 154 note 4 Reise nach Island. Appendix, p. 295.

page 154 note 5 Mineralogische und petrographische Mittheilungen. B.IV. 1882. p. 414.

page 154 note 6 Notes pour servir à I'étude de la Géologie de l'islande et des lies Foeroe. 1884. p. 17.

page 154 note 7 The specimens employed for the purposes of the present paper have been kindly put into my hands by Professor Judd, to whom also for advice and direction I am most deeply indebted.

page 154 note 8 Quart. Journ. Geol. Soc. Vol. XLII. (1886) p. 71.

page 154 note 9 Dr. Geikie mentions, on the authority of Mr. Clough, of the Geological Survey of Scotland, the existence of very large crystals of felspar in some of the basic dykes of Argyllshire. Trans. Royal Soc. Edin. Vol. XXXV. Pt. 2. p. a7 (1888).

page 155 note 1 This result is an average of six experiments which varied between 93° 30' and 93° 40', the wide difference being accounted for by the imperfect lustre of some of the faces of the cleavage plates, giving, thereby, only an imperfect reflection of the object employed.

page 156 note 1 Loc. cit. p. 18 and Pl. II. fig. 2.

page 157 note 1 “On peut Dependant remarquer dans les feldspaths des petites cavites rectangulaires alignées suivant les lignes de clivage et remplies de produits opaques dus à l'alteration.” Loc cit. p. 18.

page 157 note 2 Untersuchung des Eruptionproducte des Hekla. Loc. cit. p. 18.

page 157 note 3 This author gives a second analysis, in which he lost the alumina and neglected to estimate the soda and potash; but the results calculated differ but slightly from those quoted above.

page 158 note 1 Shirlitz, loc. cit. p. 435.

page 158 note 2 von WalterBhausen. “ Ueber die vyulkanischen Gesteine in Sicilien und Island.” Göttingen, 1853, p. 22.

page 158 note 3 Damour, loc. cit. p. 87.

page 158 note 4 Forchhammer, loc. cit. p. 388.

page 159 note 1 Schirlitz, loc. cit. p. 435.

page 159 note 2 Foichhammer, Ice. cit. p. 387.

page 159 note 3 Damour, he. cit. p. 88.