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Published online by Cambridge University Press: 01 May 2009
By correlating the head and the tail of Professor G. P. Merrill's “Discussion on the use of the terms Rock-weathering, Serpentinization, and Hydrometaraorphism,” I infer a direct invitation to confer with him on the questions raised by me at the Bristol meeting of the British Association.
page 540 note 1 Geol. Mag., August, 1899, pp. 354–8.
page 540 note 2 “The Comparative Actions of Subaërial and Submarine Agents in Rock Decomposition”: Rep. Brit. Assoc, 1898, p. 868; Geol. Mag., January, 1899, p. 30.
page 540 note 3 “Rocks and Rock-weathering,” pp. 161 and 174 (footnote).
page 541 note 1 Allgemeine und Chem. Geol., vol. i (1879), pp. 1, 2, 43, 47, and 159.
page 540 note 2 As results of complicirte Verwitterung Roth included the zeolites and many of the minerals considered by Professor Merrill to be due to agents of deep-seated origin I agree with Professor Merrill's list (serpentine not being on it), but I see no support for our views in the writings of Roth. His later use of the expression agrees exactly with the statements made in earlier papers, where the verb is not given an adjectival form, as in “complicirt sich die Verwitterung des Felsitporphyrs durch Zufuhr von Kalk und Eisen aus nahe gelegenen Partien, so entstehen ‘Epidosite’ Gesteine' (Abhand. der Akad. der Wiss., Berlin, 1869, ii, 133).
page 540 note 3 Abhand. der Akad. der Wiss., Berlin, 1869, ii, 345 and 346.
page 542 note 1 That serpentine loses water by exposure to the weather is not in itself, however, a proof that the previous hydration of the olivine was not effected by atmospheric water. Laterite, which is unquestionably a product of true, though peculiar, weathering, loses water on exposure even to a humid atmosphere.
page 542 note 2 W. Lindgren in 1896 also referred to serpentinization as a deep-seated process, which, he said, should not be referred to weathering: 17th Annual Report, U.S. Geol. Surv., pt. ii (1895–6), p. 92.
page 542 note 3 GEOL. MAG., August, 1899, p. 356.
page 542 note 4 pp. 24, 25, 97, 158, and 159.
page 543 note 1 “Rocks and Rock-weathering,” pp. 161 and 174 (footnote).
page 543 note 2 Quart. Journ. Geol. Soc, vol. xxxiv (1878), p. 82.
page 543 note 3 Quart. Journ. Geol. Soc. vol. xlvi (1890), pp. 341–382.
page 543 note 4 “On Augite-diorites with Micropegmatite in Southern India”: Quart. Journ. Geol. Soc, vol. liii (1897), p. 405.
page 543 note 5 In a memoir on the Salem rocks, now in the press, evidence is given which indicates an origin similar to this for the magnesite which is so constantly found veining the peridotite masses in South India. Most, if not all, these peridotite eruptions are accompanied by masses of white quartz containing liquid carbonic acid. The association of these two rocks is too constant to be fortuitous, and is suggestive of a genetic relationship, the quartz being more probably the siliceous end-product of the eruption in each instance, and in the absence of alumina and alkalies consolidates as simple quartz instead of forming alumino-alkaline silicates. That being so, the large quantities of carbonic acid under pressure might attack the olivine, with formation of magnesite and separation of chalcedonic silica. The water associated with the carbonic acid accounts for the small quantities of picrolite always found in these peridotites, which, however, never show a general serpentinization of the mass.
page 543 note 6 “Origin of the constituent and adventitious Minerals of Trap and the allied Rocks”: Amer. Journ. Sci., vol. xlix (1845), pp. 49–64.
page 544 note 1 Amer. Journ. Sci., ser. III, vol. xx (1880), pp. 331–2.
page 544 note 2 “Considerations on Volcanoes,” 1825, pp. 126–7.
page 544 note 3 “Ancient Volcanoes of Great Britain,” 1897, vol. i, pp. 16, 17; vol. ii, p. 189.
page 545 note 1 This belt has been the only serious rival with which Peninsular India has had to compete in the mica market, and the preservation of large sheets of delicate muscovite in coarse-grained pegmatite is generally a safe index of geological stability and quiescence.
page 545 note 2 See Dana's“ Manual of Geology,” 4th ed. (1895), pp. 412, 443, 536, 633, 735, 813, and 881.
page 546 note 1 Trans. Amer. Inst. Mining Engineers, Feb., 1899; see also literature therein quoted.
page 546 note 2 See McGee's Geological Map of the United States, 1884.
page 546 note 3 Neues Jahrb. f. Min., 1880, ii, pp. 187–192.
page 547 note 1 Cf. Dana, J. D., Amer. Journ. Sci., vol. xlix (1845), pp. 57 and 58Google Scholar.
