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XIII. The Old Red Sandstone of the Orkneys

Published online by Cambridge University Press:  06 July 2012

Extract

As the result of two visits to Orkney, in which he was accompanied by Mr B. N. Peach, he pointed out that the yellow sandstones of Hoy did not pass down conformably into the flagstones which form the basis of that island, but were separated from them by a marked unconformity. At the base, of the upper sandstones lay a series of contemporaneous lavas and ash beds, which were in all probability erupted, from certain ‘necks’ in the low-lying district at the foot of the Hoy Hills. These rocks he regarded as belonging to the upper Old Red Sandstone. The lower Old Red Sandstone consisted principally of a great thickness of flagstones, with which were interstratified beds of yellow and red sandstone, and occasionally of conglomerate. The fossils belonged exclusively to this lower series; and a table is given, compiled by Mr C. W. Peach, showing the distribution 9f fossil fishes in the lower Old Red Sandstone of Lake Orcadie, including those of Orkney so far as known at that time. As Sir Archibald Geikie anticipated, subsequent revision has necessitated “considerable pruning of the fossil lists.” The conglomerates around the granite axis of Stromness formed merely a local base, “due to the uprise of an old ridge of rock from the surface of the sheet of water in which these strata were accumulated,” and were presumably not on the same horizon as the thick conglomerates on which, in Caithness, the lowest flagstones rest. The sandstones interbedded with the flagstones in South Ronaldshay were regarded as in all probability the northward continuation of the similar rocks at Gill's Bay, Huna, and John o'Groats, on the south side of the Pentland Firth. From a geological point of view, the brief notice of the Old Red Sandstone of the Orkneys contained in this paper forms by far the most important contribution to the knowledge of the subject published up to that time.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1900

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References

page 384 note * Sir Geikie, Arch., “The Old Red Sandstone of Western Europe,” pt. i., Trans. Roy. Soc. Edin., vol. xxviii. pp. 409 and 410.Google Scholar

page 384 note † Mineralogical Magazine, “The Geognosy and Mineralogy of Scotland,” part v.—Orkney, M. Foster Heddle, M.D., 1880, p. 102.

page 384 note ‡ Proc. Roy. Phys. Soc. Edin. 1880

page 385 note * Quart. Jour. Geol. Soc. Lond., vol. 36.

page 385 note † London, 1883.

page 385 note ‡ The occurrence of this basalt was noted by Jameson, Mineralogy of the Scottish Isles, ii. 235.

page 385 note § Proc. Roy. Phys. Soc. Edin., vol. xiii

page 385 note || Peach and Horne, op. cit. Sir A. Geikie Old Red Sandstone, p. 409.

page 386 note * Op. cit.

page 386 note † Archibald Geikie, op. cit., p. 410.

page 387 note * A. Smith Woodward, B.M. Cat.—Fossil Fishes, pt. ii. p. 291.

page 387 note † “Achanarras Revisited,” Proc. Roy. Phys. Soc. Edin., xii. 285.

page 390 note * Peach and Horne, Proc. Roy. Phys. Soc, Edin., 1880, p. 3.

page 391 note * Hugh Miller, Footprints of the Creator, p. 2.

page 391 note † Heddle, Geognosy of Scotland—‘Orkney,’ p. 135.

page 394 note * Peach and Horne, Old Red Sandstone or Orkney, p. 10

page 395 note * Sir A. Geikie, Old Red Sandstone, pt. i. p. 410.

page 398 note * Noted by Jameson, Scottish Isles, ii. 239.

page 398 note † Peach and Horne, Old Red Sandstone of Orkney, pp. 8 and 9.

page 398 note ‡ Heddle, Geognosy of Scotland, part v. p. 101.

page 398 note § Peach and Horne, Old Red Sandstone of Orkney, p. 7.

page 399 note * Heddle, op. cit., p. 122.

page 399 note † Peach and Horne, op. cit., p. 2.

page 399 note ‡ Peach and Horne, op. cit., p. 9.

page 401 note * Peach and Horne, op. cit., p. 11.

page 402 note * Cruise of the Betsy, p. 394.

page 403 note * Peach and Horne, op. cit., p. 12.

page 404 note * Peach and Horne, op. cit., p. 11.

page 405 note * Heddle, op. cit., pl. xiv.

page 406 note * Sir Geikie, A., “Old Red Sandstone,” Trans. Roy. Soc. Edin., vol. xxviii. p. 393.Google Scholar

page 407 note * Sir A. Geikie, “Old Red Sandstone,” p. 363.

page 408 note * Sir A. Geikie, Old Red Sandstone, pt. i. p. 405.

page 408 note † British Association Meeting at Aberdeen, 1858.

page 408 note ‡ Egerton, Geological Survey Decade. Traquair, Geological Magazine, Nov. 1888. Proc. Roy. Phys. Soc. Edin., 1896.

page 409 note * Peach and Horne, op. cit., p. 11 and 12.

page 409 note † Peach and Horne, op. cit., p. 12.

page 410 note * Peach and Horne, op. cit., p. 5.

page 411 note * Jameson, , Mineralogy of the Scottish Isles, vol. ii. p. 257Google Scholar.

page 411 note † Heddle, Geognosy of Scotland, v. p. 103.

page 411 note ‡ Peach and Horne, op. cit., p. 5.

page 412 note * Jameson, Mineralogy of the Scottish Islands, ii. 235.

page 412 note † Peach and Horne, op. cit., pp. 9 and 13.

page 413 note * Trans. Roy, Phys. Soc. Edin., vol. xiii.

page 416 note * Sir Geikie, A., “Old Red Sandstone,” Trans. Roy. Soc. Edin., vol. xxviii. p. 406.Google Scholar

page 416 note † The Black Holm of Copinshay consists of an intrusive sheet of olivine diabase about 30 feet thick, enclosing a large mass of baked flag penetrated by numerous veins. This is probably that referred to by Jameson, Scottish Islands, ii. p. 235.

page 420 note * Sir A. Geikie, Old Bed Sandstone, p. 404.

page 420 note † Traquair, Proc. Roy. Phys. Soc. Edin., vol. xii., 1894.

page 422 note * Trans. Geol. Soc. Edin., 1892.

page 423 note * This list has been compiled from—Traquair, “Fossil Vertebrates of the Moray Firth”; Traquair, “Achanarras Revisited”; A. S. Woodward, British Museum Catalogue of Fossil Fishes.