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Published online by Cambridge University Press: 17 January 2013
“Boulder-clay” or “till,” abundant in Scotland, and occurring also in England, Ireland, and in some other parts of North-Western Europe, has long been, and still is, a puzzle to geologists.
Sir James Hall, about fifty years ago, in this Society, was the first to draw attention to the deposit, by describing its composition, and endeavouring to explain its origin. He saw that it could not be included in either of the two great classes into which rocks were then divided. It was a deposit sui generis, bearing no resemblance to anything known, except a heap of rubbish, there being in the arrangement of its ingredients no regard to specific gravity or size.
page 655 note * Sir James Hall's theory is explained by him in the following paragraph:—“I imagine that a diluvial wave flowed at some remote period from a westerly or north-west direction, and broke over our island; that its magnitude was such, that a great body of its water crossing the ridge of country which separates the two coasts, overwhelmed the district, discharging itself into the German Ocean.”—(Ed. B. S. Tr. vol. vii. p. 202.
page 656 note * “Visit to the Brazils,” p. 403.—Agassiz in this work contends for the existence of “a sheet of snow 10,000 or 15,000 feet in thickness, extending all over the northern and southern portions of the globe,—which in the end formed a northern and southern cap of ice moving towards the equator!”
page 659 note * See Edin. Phil. Journal for 1842, p. 227Google Scholar; and Geological Researches, by James Smith of Jordanhall, p. 12.
page 659 note † “Isle of Man,” by Cumming, p. 248.
page 659 note ‡ Proceedings of the Geological Society of London for 1866, p. 269.
page 660 note * Glacial Drift, p. 43.
page 660 note † Lond. Geolog. Journal for 1850, vol. viGoogle Scholar.—Isle of Man, pp. 115, 247.
page 660 note ‡ Lond. Geolog. Journal for 1852, vol. viii. p. 417.Google Scholar
page 661 note * Lithology of Edinburgh.
page 661 note † Lond. Geolog. Journal for 1866, p. 167.Google Scholar
page 661 note ‡ Glacial Drift, p. 45.
page 661 note § Edin. Phil. Journ. for 1842, vol. xxxiii. p. 223.Google Scholar
page 662 note * Lond. Geolog. Journ. for 1866, p. 268.Google Scholar
page 662 note † Edin. New Phil. Journ. for 1852, vol. liv.Google Scholar
page 662 note ‡ Ibid.
page 662 note § Proceed. Geolog. Soc. of London for January 1865.
page 662 note ∥ Ibid.
page 664 note * This boulder was pointed out to me by Mr Stevenson of Dunse.
page 664 note † Geology of Roxburghshire, Roy. Soc. Trans, vol. xv. p. 402.Google Scholar
page 665 note * Geology of Clydesdale, p. 271.
page 665 note † Highland Society's Transactions for 1843.
page 665 note ‡ Transactions of Berwickshire Naturalists' Club, vol. v. pp. 238, 372.Google Scholar
page 665 note § Lond. Geol. Journ. for 1862, vol. xviii. p. 377.Google Scholar
page 665 note ∥ Lond. Geol. Journ. for 1858, vol. xiv.Google Scholar
page 666 note * Lond. Geolog. Soc. August 1846, pp. 336 and 342.Google Scholar
page 666 note † British Assoc. Rep. for 1863, vol. xiii. p. 51.Google Scholar
page 666 note ‡ Geologist for 1862, p. 246.
page 666 note § British Assoc. Rep. for 1864.
page 666 note ∥ Edin. Roy. Soc. Trans, for 1815, vol. vii. pp. 244–265.Google Scholar
page 667 note * Voyage to Iceland and the Faroe Isles.
page 667 note † Letter from Dr Hjaltelin, Knight of the Dannebrog, and Chief Physician in Iceland.
page 668 note * Lond. Geolog. Journal for 1845, vol. i. p. 376.Google Scholar
page 668 note † Thus Mr Maclaren says—“I have pointed out a boulder of mica slate in the Pentland Hills, weighing 8 or 10 tons, which must have come 50 miles at least. It lies on a steep acclivity 1000 feet above the sea; and it must have passed over extensive tracts of country from 500 to 800 feet lower than the spot on which it rests. Even were all Scotland converted into a mer de glace, like Greenland, no glacier could carry the boulder (and there are many such) from its parent rock, in Perthshire or Argyleshire, to the Pentlands.”—Select Writings, vol. ii. p. 115.Google Scholar
page 669 note * Lond. Geolog. Society's Proceedings for April 1849, p. 13.
page 670 note * Ed. R. S. Tr. vol. vii. p. 200.
page 670 note † Researches, p. 141.
page 670 note ‡ Smith's Researches, p. 143.
page 670 note § Proceedings of the Lond. Geolog. Society for 1866, pp. 274–5.Google Scholar
page 670 note ∥ Ibid. p. 267.
page 670 note ¶ Brit. Assoc. Reports for 1864, p. 62.
page 671 note * Brit. Assoc. Reports for 1864, p. 58Google Scholar; R. S. E. Tr. vol. xxiv. p. 617.
page 671 note † Trans. Glasg. Geol. Soc. vol. iii. p. 150.Google Scholar
page 671 note ‡ Berwickshire Nat. Club, vol. v. p. 238.Google Scholar
page 671 note § Vol. xxiv.
page 671 note ∥ Proceed, of Lond. Geolog. Society for January 1865, pp. 175 and 196.Google Scholar
page 672 note * Glacial Drift, pp. 54 to 65.
page 672 note † Thus Dr Watson, in describing the boulder-clay of Arran, says that the shells in it “are very much broken. The shells may often be found crushed, yet with each fragment in its own place. Some of the large specimens of Cyprina, though unbroken, are indented, as by a sudden violent blow. The whole condition of the shells suggests that heavy stones have been dashed down upon them.” Dr Bryce also notices that the Arctic shells found by him in Arran were “in single valves or in a fragmentary state, yet not so small but that the species can be determined.”—Geology of Arran, p. 168.
The shells in the boulder-clay of Caithness have been examined by a great number of competent geologists, who all give the same testimony. Mr Peach describes the shells so “broken” and “rubbed” he could find only one entire shell. Messrs Crosskey and Robertson of Glasgow, having gone to Caithness on purpose to examine the boulder-clay there, describe it as “a hard and compact mass, with striated and polished boulders, being in appearance similar to that in the west of Scotland. The shells are thinly interspersed from top to bottom, and are of a water-worn and fragmentary character. They appear equally distributed, as if the whole mass had been mixed up and kneaded together.”—Geolog. Society of Glasgow Trans. vol. iii. p. 126Google Scholar. Mr Jameson of Ellon says that the drift-beds of Caithness contain “remains of sea-shells all through them, and these are broken, rubbed, and scratched, and evidently by the same agency that marked the rocks and boulders.” His theory to account for the facts, is, that “much floating ice seems to have passed over the district from the N.W., which crushed and destroyed these marine beds, broke the shells, and mixed them up with other superficial debris into that mass of rough pebbly mud which now overspreads the surface.”—Proceed, of Lond. Geol. Society for 1865, pp. 176–7.Google Scholar
Mr Jameson has also the following statement regarding a deposit of boulder-clay near Paisley which he examined. He says—“I sometimes found, on heaving up a boulder, a number of young crushed mussel-shells beneath it, as if they had been squashed by the fall of the stone. The clay around also occasionally exhibited black stains, as if from the decay of sea-weed that had been attached to the stone.”
At the various places where the Rev. Mr Crosskey found sea-shells in boulder-clay, along the coasts of Scotland, England, and Ireland, the shells were “very fragmentary, and even single valves are seldom found whole.”—Glasg. Geol. Soc. Trans. vol. iii. p. 151.Google Scholar
page 673 note * Notes of a Ramble through Wales, by Symonds, W. S., 1864, p. 12.Google Scholar
page 674 note * Geikie on Glacial Drift, p. 93.
page 674 note † Bones of elephants, rhinoceros, &c., are found in Siberia very generally associated with Arctic sea-shells. (Lyell, “Principles,” i. 183; Quart. Journ. Lond. Geolog. Society, 1st Feb. 1848.Google Scholar)
page 675 note * Lyell, “Antiquity of Man,” p. 138. Mr Geikie (“Glacial Drift,” p. 119), after alluding to cases where “beds of clay were fairly bent back upon each other,” says, “such contortion must be due to powerful pressure. It may have been produced by masses of ice standing here, and pushed onward, partly by their own impetus, partly by the action of winds or currents. The compression to which such a weight of ice would give rise, would probably be quite sufficient to corrugate beds of clay and sand.”
page 675 note † Proceed, of Geol. Society for 1851, vol. vii. p. 289.Google Scholar
page 675 note ‡ E. Ph. J. for 1856, vol. iv. p. 222.Google Scholar
page 676 note * Two of these sections are given on Plate XXXI.
page 677 note * See a short paper on this subject by Principal Dawson, of Montreal, in the “Canadian Naturalist.”
page 677 note † Lond. Geolog. Journal, vol. ix. p. 306.Google Scholar
page 677 note ‡ De La Bëche, , Geolog. Observer, p. 266.Google Scholar
page 678 note * The Open Polar Sea.
page 678 note † North Atlantic Sea-Bed, p. 40.
page 678 note ‡ SirLyell, Charles—(1) Travels in North America, vol. ii. p. 173Google Scholar; (2) Loud. Geolog. Journal for 1849, Trapolli in Scandinavia; Lond. Geolog. Journal for 1868, xcviii.
page 679 note * Lond. Geolog. Journal for 1868, vol. xvi. p. 433.Google Scholar
page 679 note † Franklin's, Journey in 1823, pp. 499, 501, 583.Google Scholar
page 679 note ‡ Phil. Journal for 1841, vol. xix. p. 530.Google Scholar
page 680 note * These interesting and instructive facts will be found stated in a Memoir, by Mr Gywn Jeffreys, in the British Association Reports for 1863; and also in a paper, by Professor Sars of Christiania, in the Edinburgh Phil. Journal for 1863.
page 682 note * Dr Hjaltelin of Iceland, in his letter to Mr R. M. Smith, quoted on page 667, mentions—“I have seen the secular elevation of the northern shores of this island; and it is not unlikely that the north coast of Greenland is in a similar state.” Therefore it is probable that the north extremity of Iceland rose up simultaneously with North Greenland.
page 683 note * Allusion is probably here made to the remains of the woolly-haired elephant, rhinoceros, musk ox, rein-deer, black bear, and polar bear having been found in pleistocene beds in various parts of Great Britain. If, as is believed, these animals belong naturally to North America, how did they reach the small island of Britain?
page 683 note † In a list of sea-shells given by Mr Jameson of Ellon, as found in the boulder-clay and other pleistocene beds of Scotland, amounting altogether to 137, he represents 134 as now living in the Arctic circle, 60 in North-Eastern America, 26 in the North Pacific, and 82 in British seas. The number now living in the Arctic circle, North-Eastem America, and North Pacific, but not in British seas, is 52.
page 683 note ‡ Professor E. Forbes mentions, in illustration of this point, the Eriocaulon septangulare, “known in Europe only in the Hebrides, and at Connemara, in the west of Ireland. Elsewhere,” he says, “it is an inhabitant of Boreal America, which is its true native country, and from whence, by means of transport, it has in all probability been introduced naturally into the British Isles.” Professor Balfour has given to me the names of the following additional plants, natives of Labrador and Canada, which are found in Skye and on the west coast of Ireland, but nowhere else in Europe, viz., Neottia gemmipara and Sisyrinchium anceps.
page 684 note * Journ. of London Geological Society for 1845, vol. i. p. 373.Google Scholar
page 685 note * Edin. New Phil. Journ. for 1846, vol. xl. p. 141.Google Scholar
page 685 note † Proceedings Roy. Soc. Edin. vol. iii. p. 461.Google Scholar
page 685 note ‡ Ancient Glaciers of Wales, p. 80.
page 686 note * Professor Ramsay mentions (p. 96), that sea-shells were found by him at a height of 1300 feet above the sea, “two miles west of Snowdon, on a sloping plain of drift charged with erratic blocks, one of which, of great size, is known as Maen-bras, or the large stone.”
page 686 note † Proceed. Lond. Geolog. Society, vol. viii. p. 373.Google Scholar
page 686 note ‡ Anc. Gl. of Wales, p. 92.
page 686 note § De Luc (as quoted by Sir James Hall, Ed. R. S. Tr. vol. vii. p. 160) says, “that the granitic blocks lying in the district between Berlin and the Baltic, occur frequently, and almost constantly, in very numerous assemblages, upon the summits of the sandy hills with which that country is interspersed, whilst none are to be met with in the intervening valleys.”
page 687 note * Glacial Drift, by A. Geikie, p. 75.
page 688 note * Proceed. Lond. Geolog. Society for Nov. 1838.Google Scholar
page 688 note † Proceed. Lond. Geolog. Society for Nov. 1838, pp. 179, 331.Google Scholar
page 688 note ‡ Hibbert, , Edin. Journ. of Science for 1831, vol. iv.Google Scholar
page 689 note * Chambers on “Faroe and Iceland,” p. 28.
page 689 note † In Finmark and Northern Russia blocks have been found which have also been referred to Scandinavia as their source.
page 689 note ‡ At St Abb's Head, the rocks, about 200 feet above the sea, were found striated, when the boulder-clay was removed from them, but at no other places.
page 689 note § Edin. New Phil. Journal for 1853, vol. liv. p. 250.Google Scholar
page 690 note * Sir Ch. Lyell gives proof that the forest and lignite beds of Cromer were preceded and followed by a period of glacial cold. These forest and lignite beds “underlie the great mass of glacial drift, in part unstratified, and containing boulders and angular blocks transported from great distances.”—Princ. vol. i. p. 197.
page 691 note * Trans. Roy. Soc. Edin. vol. xxiv. p. 633.Google Scholar
page 691 note † Newer Pliocene Geology, by Smith, , p. 35.Google Scholar
page 691 note ‡ Roy. Soc. Tr. vol. xxiv. pp. 619 and 633.Google Scholar