^{page 439 note *} Hutton, 's “Theory of the Earth,” vol. i. p. 155Google Scholar, et seq.

^{page 439 note †} Playfair's “ Illustrations of the Huttonian Theory,” § 255, et seq.

^{page 439 note ‡} See “ Trans. Roy. Soc. Edin.” (1805), vol. v. p. 43.

^{page 439 note §} See “Mem. Wern. Soc” ii. 178, 618; iii. 225; “Edin. Phil. Journ.” i. 138, 352; xv. 386.

^{page 439 note ║} “Trans. Roy. Soc. Edin.” (1811), vi. p. 405.

^{page 439 note ¶} “Tracts and Observations in Natural History and Physiology,” 8vo, Lond. 1799.

^{page 439 note **} “Trans. Roy. Soc. Edin.” (1833), xiii. p. 39, 107.

^{page 439 note ††} “Mem. Wern. Soc.” vii. p. 1. Published separately, 1838.

^{page 439 note ‡‡} Small 8vo, Edin. 1838, first partly published as articles in the Scotsman newspaper.

^{page 446 note *} Descriptions of the geological structure of Arthur Seat will he found in Maclaren's “ Geology of Fife and the Lothians,” and in the “ Geological Survey Memoir of Sheet 32, Scotland.” Mr Judd has offered an explanation of one part of the history of the hill (Quart. Journ. Geol. Soc., vol. xxxi. p. 131), which I believe to be quite untenable It will be referred to elsewhere.

^{page 448 note *} See “ Memoir on East Lothian,” Geol. Survey Memoirs, chap. v.

^{page 450 note *} B. N. Peach, in Explanation to Sheet 31, “ Geo. Surv. Scotland,” p. 15.

^{page 450 note †} B. N. Peach, op. cit. p. 45.

^{page 451 note *} A small outlier of tuff among the sandstones on the shore to the east of Cramond may be an exception to the statement in the text; but this mass might belong to some isolated cone between the West Lothian and Fife districts.

^{page 453 note *} “Geological Magazine,” vol. iii. p. 243.

^{page 454 note *} In the valley of the Nith and its tributary the Carron Water, among the high grounds of Dumfrieshire, necks belonging to the Permian series of volcanoes occur. At the head of Lauderdale, Mr B. N. Peach has observed a small neck coming through the Upper Old Red conglomerate, and possibly connected with the volcanic action in which the Berwickshire and Roxburghshire porphyrites were erupted. But in these cases the orifices have been opened in deep valleys among the hills. [Since this was written, Mr Peach has met with a number of volcanic necks of Lower Carboniferous age in valleys of the Silurian uplands of Roxburghshire, extending to a distance of at least 10 miles from the edge of the lava-sheets.]

^{page 459 note *} “Trans. Roy. Soc. Edin.” xxviii. p. 487.

^{page 460 note *} See “Geology of East Lothian,” Geological Survey Memoir, p. 40.

^{page 462 note *} Trans. Roy. Soc. Edin. vol. xxviii. p. 223.

^{page 462 note †} Op. dt. xxviii. 522.

^{page 463 note *} Op. cit. xxviii. p, 481, et seq.

^{page 470 note *} Quarterly Journ. Geol. Soc. 1860, p. 245.

^{page 474 note *} See Explanation to Sheet 31, “ Geological Survey of Scotland,” par. 21 (1878), mapped by Mr R. L. Jack.

^{page 475 note *} See Hay Cunningham's “ Essay,” p. 66, and plate ix,, and “ Geol. Survey Memoir on Geology of Edinburgh,” p. 114.

^{page 477 note *} Explanation of Sheet 31, “ Geological Survey of Scotland,” §§ 43 and 83.

^{page 482 note *} “Geol. Magazine,” vol. i. p. 22.

^{page 483 note *} See “ Geological Survey Memoir of Edinburgh,” p. 45.

^{page 484 note *} See “ Geol. Surv. Mem., Geology of Edinburgh,” p. 58.

^{page 485 note *} “ Geol. Survey Memoirs,” op. cit. p. 49, et seq.

^{page 485 note †} “Proc. Roy. Soc. Edin.” vol. ix. p. 367.

^{page 486 note *} “Quart. Journ. Genl. Soc.” vol. xxx. p. 529.

^{page 486 note †} These sections have been excellently prepared, in the petrographical laboratory of the Geological Survey of Scotland, by A. Macconochie and R. Lunn.

^{page 492 note *} Sheet 14, “ Geological Survey, Scotland, Dec. 1868,” and Explanation of same.

^{page 493 note *} “ Mikroskopische Beschaffenheit der Mineralien und Gesteine,” 1873, p. 291.

^{page 493 note †} “Quart. Journ. Geol. Soc.” ut supra.

^{page 497 note *} Op. cit. p. 273.; Vogelsang's “Krystalliten.”

^{page 498 note *} The infusibility of the felspar has been well shown in some recent experiments on the rocks of the neighbourhood of Edinburgh. At my request, Dr R. S. Marsden has subjected some of these rocks to fusion at the laboratory of the University of Edinburgh, and I have had microscopic sections prepared of the products obtained. The basalt of Lion's Haunch is peculiarly instructive. Its large labradorite crystals have resisted the intense white heat which, continued for four hours, has reduced the rest of the minerals to a perfect glass. We can thus well understand how large definite crystals of felspar should have appeared in dykes and veins while the rock was still thoroughly liquid. The glass obtained from the Lion's Haunch rock is of a honey-yellow, and contains translucent tufted microlites. The iron forms beautiful dendritic films in the cracks. Altogether, the glass presents a strong resemblance to the peculiar substance found in some of the tuffs of the vents to be afterwards described. I am at present engaged in a series of experiments on the fusion of volcanic rocks and artificial slags, and hope to communicate the results in a future paper to the Society.

^{page 503 note *} See his Basalt-Gesteine, 1870, and “ Report of Geol. Explor., 40th Parallel, Microscopical Petrography ” (vol. vi.), p. 229. Washington, 1876.

^{page 515 note *} Since the above description was written, I have had an opportunity of examining the artificially fused products of some of the basalts and dolerites from the neighbourhood of Edinburgh (ante, p. 498, note). The resemblance of this altered serpentinous cellular substance, so abundant in some of the volcanic vents, to the glass obtained by fusing such a basalt as that of the Lion's Haunch, is so remarkable as at once to suggest an original similarity of condition. This glass, artificially obtained from some rocks like that of the Lion's Haunch, where the felspar resists fusion, must consist mainly of olivine and augite with diffused magnetic iron, and, as I have already said, it contains tufted microlites not unlike those of the tuff-lapilli.