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VI. — The Igneous Geology of the Bathgate and Linlithgow Hills. Part. II. Petrography

Published online by Cambridge University Press:  06 July 2012

J. D. Falconer
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Extract

The lavas of the Bathgate and Linlithgow Hills occur, as already described, in a series of zones alternating with sedimentary deposits. So far as their field characters are concerned they may be grouped with convenience into two classes: fine-grained, columnar, basaltic types, usually porphyritic with augite and olivine, rarely with felspar, and coarser-grained, doleritic types, usually much decomposed, not evidently porphyritic or porphyritic with olivine alone. The yellow crusts of the compact lavas are minutely vesicular and pumiceous, while steam-cavities are rare in the interior. The doleritic lavas on the other hand are coarsely vesicular and amygdaloidal above and below, and frequently also throughout. The blue basaltic types are relatively very fresh; the doleritic types are frequently entirely decomposed into a whitish, earthy material, with knots of limonite, calcite, and quartz, similar in many respects to the white trap of the coal-fields. Good examples of this mode of weathering may be found in the Riccarton Burn. The differences in texture are probably to be referred not so much to differences in chemical composition as to the effect of variation in the quantity of water vapour contained in the successive flows. The coarse and open structure of the dolerites has evidently also given freer scope to the action of decomposing influences than the more compact structure of the basalts. Both types are much veined by such secondary minerals as calcite, siderite, limonite, quartz, chalcedony, and various zeolites. Frequently cavities in the veins, steam-holes in the pumiceous crusts, and even vesicles within the solid rocks, are found filled with brown viscous pitch or black lustrous asphalt. Such occurrences undoubtedly indicate that these rocks have been subjected to some slight extent to post-volcanic pneumatolytic action.

Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 45 , Issue 1 , 1906 , pp. 133 - 150
Copyright
Copyright © Royal Society of Edinburgh 1906

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References

page 133 note * Falconer, , Trans. Roy. Soc. Edin., vol. xli., 1905, p. 359Google Scholar.

page 135 note * Evans, , Quart. Journ. Geol. Soc., vol. 57, 1901, p. 49CrossRefGoogle Scholar; see also Flett, , Trans. Roy. Soc. Edin., vol. xxxix, 1900, p. 865CrossRefGoogle Scholar.

page 136 note * Geikie, A., Trans. Roy. Soc. Edin., vol. xxix., 1880, Pl. XI. fig. 4Google Scholar.

page 136 note † Ibid., Pl. XI. fig. 5.

page 137 note * The Tuffs accompanying the lavas have not been investigated in any detail. For a short description of these, see Geikie, , Trans. Roy. Soc. Edin., vol. xxix., 1880Google Scholar.

page 137 note † Geikie, A., Trans. Roy. Soc. Edin., vol. xxxv., 1896, p. 21Google Scholar.

page 137 note ‡ Cf. “The Geology of Eastern Fife,” Geol. Sur. Mem., 1902, p. 190.

page 139 note * Geikie, A., Trans. Roy. Soc. Edin., vol. xxix., 1880Google Scholar.

page 139 note † Stecher, , Tsch. Min. u. Petr. Mitth., vol. ix., 1887Google Scholar.

page 139 note ‡ “The Geology of Eastern Fife,” Geol. Sur. Mem., 1902, p. 391.

page 140 note * Cf. “Sub-ophitic” structure, Watts in Geikie's Ancient Volcanoes of Great Britain, vol. i. p. 147Google Scholar.

page 140 note † Rosenbusch, , Mikro. Phys., vol. ii. p. 130Google Scholar.

page 141 note * See Harker, , Quart. Journ. Geol. Soc., vol. 1., 1894, p. 317Google Scholar.

page 141 note † Flett, Geol. Sur. Mem., sheet 55, p. 128.

page 142 note * Mikroskopische Physiographie, etc., vol. ii. p. 1108.

page 142 note † Cf. Holland, , Quart. Journ. Geol. Soc., vol. liii., 1897, p. 405CrossRefGoogle Scholar.

page 143 note * Teall, British Petrography, 1880, p. 163.

page 143 note † Monckton, , “The Stirling Dolerite,” Quart. Journ. Geol. Soc., vol. li. p. 48Google Scholar.

page 143 note ‡ Cf. Vogt, Zeitschrift für praktische Geologie, April 1893, fig. 27.

page 145 note * Lacroix, , Minéralogie de la France, vol. ii. p. 36Google Scholar. Cf. also “Myrmekitic Structure,” Weinschenk, Die gesteinsbildenden Mineralien, p. 75.

page 145 note † Flett, , Trans. Geol. Soc. Edin., vol. viii. p. 485Google Scholar.

page 145 note ‡ Zirkel, , Lehrbuch der Petrographie, vol. ii. p. 699Google Scholar.

page 146 note * Teall, Geol. Mag., 1889, p. 481; Flett, , Trans. Roy. Hoc. Edin., vol. xxxix., 1900, p. 865CrossRefGoogle Scholar.

page 148 note * Stecher, op. cit. p. 161.

page 148 note † Tsch. Min. u. Petr. Mitth., vol. ix., 1887Google Scholar.

page 148 note ‡ Teall, , Quart. Journ. Geol. Soc., vol. xl., 1884, pp. 209, 640CrossRefGoogle Scholar: Harker, Ibid., vol. 1., 1894, p. 311; vol. li. p. 125: Holland, Ibid., vol. liii., 1897, p. 405.

page 148 note § Trans. Roy. Irish Acad., vol. xxx., 1894, p. 477Google Scholar.

page 149 note * See Weinschenk, , Grundziige der Gesteinskunde, vol. i. p. 118Google Scholar.