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XXXII.–Geological Account of Roxburghshire

Published online by Cambridge University Press:  17 January 2013

David Milne Esq.
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It seems extraordinary, that no one should have undertaken a geological survey of Roxburghshire, more especially as the counties to the east and west of it have been examined, and accounts of their formations were published some years ago. It cannot be from its uninteresting character, that the intervening district has been neglected; for it presents as great a variety of apparently distinct formations, as there are in the adjoining counties of Dumfries and Berwick; and some of these have long been the special subjects of speculation and controversy among geologists. The British Association, in the Report of its Meeting held at Cambridge in 1833, propounded the following questions for geological inquiry.

Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 15 , Issue 3 , 1844 , pp. 433 - 502
Copyright
Copyright © Royal Society of Edinburgh 1844

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References

page 436 note * These places are indicated on the map by red dots.

page 436 note † Vol. i. p. 436.

page 438 note * Tudhope quarry is three-fourths of a mile north of Jedburgh, whilst Ferniehirst quarry is on the south side of the same valley. The rocks are, at both places, nearly horizontal; and being on the same level, as well as of the same colour, which is not a common one in the district, it is not improbable that they are portions of the same stratum, which originally stretched across the valley, before it was scooped out.

page 441 note * I saw some specimens of Lingula at Rowanburn in the fire-clay and shale lying about the pitmouth. This shell is very common in the Mid-Lothian coal-shales.

page 441 note † As great doubts are still entertained by many persons of the relative age of the dark-coloured strata of Hunthill, and the red rocks which surround this spot, I may mention, that the two sets of rocks may be seen, if not in junction, at all events within a few yards of each other, in the glen on the west side of Hunthill House. In 1839, I examined the place, at the request of some of the principal inhabitants of Jedburgh, who, on public grounds, were desirous of learning the probability of coal being found there, with the laudable view of starting a subscription to assist the proprietor in boring and sinking for it. It was then that I discovered the fossils above mentioned, which left no doubt in my mind as to the class of rocks prevailing at Hunthill, though, as they appeared to underlie the Carter limestone, I discouraged any expectation of finding a workable coal-seam. On this occasion, also, I observed that the red rocksin the glen just referred to, appeared to dip under the shales and limestones; though, from the quantity of grass and brushwood then covering the ground, no line of junction was discernible. I have been informed that last autumn (1842) Mr Adam Matheson, millwright, Jedburgh, and who possesses an ardent taste for Geological researches, made a minute inspection of the spot, for the purpose of clearing up the above point, and traced the red rocks up to the coal-measures, beneath which he and Mr Jeffrey, writer in Jedburgh (who accompanied him), distinctly saw that they dipped. He informs me, that only about 4 feet above the red sandstone strata, there is a bed of limestone about 2 feet thick, in three layers, in quality exactly resembling the limestone worked on the Carter at Meadowcleugh. About 300 feet above this limestone bed at Hunthill, a coal-seam 3 inches thick occurs.

page 441 note ‡ Sir W. Scott of Ancrum informed me (in 1840), that he ascertained this from the person who had dug through the coal in sinking the well.

page 443 note * At Roanfells, on the north side of Liddesdale, a quantity of lead was found, and a company was formed to work it. In ancient times some metal must have been smelted there, as heaps of slag and cinders are met with on the muirs.

page 444 note * Geological Society's Transactions.

page 445 note * It is observed by Mr Gregory, “that this slight deficiency is probably owing to a little water, which most limestones contain.”

page 446 note * Analysis by Dr R. D. Thomson. (Mag. of Nat. History, by Loudon, No. 29.)

page 452 note * On the top of this hill are the remains of a vitrified fort, consistingof two ramparts. The rock was well adapted for being fused, from the quantity of alkali it contains,–a quality of which the manufacturers of these forts seem to have been well aware, as the stones in all vitrified forts are of this description.

page 453 note * These two dykes I have not myself seen. They are noticed in a report by Mr Farey made out for the Duke of Buccleuch, dated 1816.

page 456 note * The best maps of the county do not, with any sort of correctness, indicate the position of the Cheviot Hills, or even the situation of the farm-houses existing among them. I found it, therefore, very difficult to lay down the dyke in this part of its course.

page 458 note * It is proper to premise, that the bearings given by Mr Oliver are true, and not magnetic.

page 462 note * This fact is taken from Farey's Report before mentioned.

page 463 note * It has been found impossible to introduce this mark into the accompanying map, on account of the smallness of the scale.

page 464 note * Vol. xvii. p. 339.

page 473 note * Two places, not far from one another, where these effects may be observed, are on the right bank of the Tweed, one opposite to Merton House, at the Craigoer rock, and the other opposite to Dryburgh, at the Holm House.

page 473 note † When this part of my Memoir was going through the press, I wrote a note to Dr Madden, stating shortly the views expressed in it. From his answer I make the following extracts, as containing some important suggestions:—

“I have just received your note, and, having considered its contents, would offer the following observations. The idea that suggested itself to me at the time of the analysis was, that the deoxidizing agent producing the white spots, must, in all probability, have been a portion oforganic matter in the act of decomposition,—this may have been a fish bone or scale, or any other organized body; there are, however, certain objections to this view of the matter, which I will now state.

“1st, If the spots were produced by the decomposition of any substance imbedded within its mass, the effect would be produced with greatest effect in the immediate neighbourhood of the decomposing body, and this effect would gradually diminish in intensity as the distance increased; whereas, in the spot, there is an abrupt transition from the deoxidized to the unaffected mineral.

“2d, As the intensity of effect would be proportioned to the decomposing mass, and as the distance to which the effect was produced would likewise be proportional, the exterior of the spots should possess a shape either exactly or nearly similar to that of the organic body inclosed; whereas, the spots in question are, without exception, nearly spherical.

“3d, The fact of the spots being annularly stratified, the rings being in most cases distinct, and easily separable by cleavage, militates somewhat against the hypothesis of the creating cause being placed in the centre, because it is generally found that annularly stratified masses grow by deposition upon a central nucleus; whereas, when a central substance influences a surrounding mass, previously deposited, a section generally exhibits radiations in place of rings.

“With regard to your other suggestion, it is exceedingly probable that the iron was brought in contact with the calcareous sand, in the form of a solution of protoxide, and that the protoxidation was an ulterior effect, possibly of heat. I do not, however, see exactly what state of things could exist so as to prevent the protoxidizing of particular spots, and, at the same time, to change so materially their structure. Some very interesting experiments have suggested themselves to me, by which I fancy we could arrive at a somewhat satisfactory conclusion respecting their origin and formation. I cannot, however, as yet promise to undertake these experiments.”

I had suggested, in my note to Dr Madden, whether clay or sand, deposited in water which held protoxide of iron in solution, would not, on exposure to heat, acquire a red colour, like common bricks or house-tyles when put into a kiln? The only difficulty is, to explain how, in particular spots, the peroxidation of the iron was prevented or subsequently neutralized. But if organic matter of any kind, (such as fish-bones or scales), containing phosphoric or carbonic acid, existed in these spots, then their organic matter would become gradually decomposed, and the acid being set free, would combine with a portion of the iron to form a protoxide, and thus discharge the red colour.

So also, in regard to the cracks and fissures, on each side of which there is a ribbon of a white or greenish-white colour,—may the peroxide originally, in that part of the stone, not have combined with the carbonic acid of the air and water, permeating these cracks, and produced similar effects?

page 474 note * Lord Greenock, to whom, as a member of Council, this Memoir was referred for examination, has, in reference to this point, written on the manuscript the following remarks: “According to Miller, who quotes the opinion of Agassiz, the remains of Holoptychius are characteristic of the upper beds of the old red sandstone, the inferior beds being distinguished by different organic fossils, viz., the midstone or cornstone formation, by the Cephalaspis, and the lower by Ptericthys, Coccosteus, Diplopterus, &c., each formation having its distinct group. Therefore, the remains of Holoptychius only having been as yet noticed in Roxburghshire, is a strong confirmation of Mr Milne's views in respect to there being little, if any, difference in age between the two descriptions of sandstone which he has noticed as existing in that county; scales, &c. of Holoptychius being likewise met with in the coal formation.”

page 475 note * For an account of the Fife fossils, see the Rev. Mr Anderson's Memoir, published in the Highland Society's Transactions; and of the Moray beds, see Sketches by Patrick Duff, Esq.

page 475 note † De La Beche, Manual, p. 450.

page 475 note ‡ The porphyry at Plewlands effervesces very briskly, and must contain a large quantity of lime.

page 476 note * Manual, p. 478.

page 476 note ‡ Analysis by Dr Thomson, given in Loudon's Mag. of Nat. History.

page 476 note † Ib. p. 475.

page 477 note * Transactions of Newcastle Natural History Society, vol. i. p. 308.

page 477 note † Mr Wood's statement is N. 83° W., which, it is presumed, are true bearings.

page 477 note ‡ Mr Adam Matheson, millwright, Jedburgh, already referred to for his geological zeal, has lately afforded additional proof of this, by actually attempting to trace the dyke from the Scottish Border through Northumberland to the sea. Having intimated to me his intention of setting out on this voyage of discovery, and asked me for instructions, I sent him out a map, compass, and other necessary implements. He writes me, that he hired a horse at Jedburgh, and set out from Hindhope along the line which, at that place the dyke appeared to run in. He has returned the map to me, having marked on it the places where he recognised the dyke. From his account, it appears to run by Clennel, Borrowden, Whittle, Dibden, Framlington, and Acklington. This last point is about seven or eight miles from the sea,—and beyond it Matheson did not proceed in his search. Though the dyke is reported by him to present a very variable direction and width—its average direction and width seem to agree with its character in these respects in Roxbughshire. The dyke at Howick, mentioned by Mr Wood, cannot therefore be the Hawick dyke, though it runs parallel with it, and about twelve miles to the north.

page 481 note * Page 82.

page 482 note * Abstract of Geological Society's Proceedings for December 1835.

page 486 note * For an account and surface-plan of Dogden Moss Kaims, see Paper by me, published in the Transactions of the Highland Society for 1836.

page 486 note † Glacial Theory, by Mr Maclaren, p. 14.

page 487 note * This word is probably a corruption for Kaim-end,—as Kaim is the term by which these elongated ridges are universally designated in the south of Scotland. The ridge here referred to has been, in several parts of Mr Laing's farm, opened, both for gravel and for sand. Its length is about half a mile.

page 487 note † Hitchcock on Deluges, Part II., p. 103.

page 487 note ‡ London Philosophical Transactions for 1835.

page 488 note * Jameson's Edinburgh Philosophical Journal for October 1843, p. 73.

page 488 note † Ibid. vol. xxiii. p. 72.

page 496 note * This Memoir was published at St Petersbourg in 1840 by the Imperial Academy of Sciences.

page 497 note * See Lyell's Elements, p. 76, 77, for examples, and an explanation of this concretionary structure.

page 497 note † Geological Researches, p. 95.