Siluria : a history of the oldest rocks in the British Isles and other countries with sketches of the origin and distribution of native gold, the general succession of geological formations, and changes of the earth's surface / by Sir Roderick Impey Murchison.
- Roderick Murchison, 1st Baronet
- Date:
- 1867
Licence: Public Domain Mark
Credit: Siluria : a history of the oldest rocks in the British Isles and other countries with sketches of the origin and distribution of native gold, the general succession of geological formations, and changes of the earth's surface / by Sir Roderick Impey Murchison. Source: Wellcome Collection.
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![and chloritic crystalline rocks. In the absence of any fossils, provided with no classification (for some years elapsed before we entered into the study of the Silurian and Cambrian rocks), we necessarily failed to clear up the order, and remained in the belief of our precursors, that the sandstones and conglomerates forming the chief mountains on the west coast, and rest- ing upon buttresses of old gneiss, were simply the equivalents of the weU- known Old Eed Sandstone of Scotland. This erroneous opinion continued to be upheld for many years, and was widely circulated in the justly popular and able work, ‘ The Old Eed Sandstone,’ of the lamented Hugh Miller. The error was first removed by a survey of the western coast of the Highlands, which I made in 1854, and in which, at my request. Professor Mcol became my companion; for I had long wished to ascertain the rationale of the singular succession I had seen many years before, and wished to search out carefully the whole order of those rocks. Some of the results were communicated to the Meet- ing of the Eritish Association at Glasgow. In the subsequent year (1855) Professor Hicol added considerably to the value of the first survey; and by his labours, combined with my own in a subsequent year, it was made manifest that the so-called ‘ Old Eed Sandstone’ of the north-western coast was a rock of much higher antiquity than that which overlies the Silurian System; for these sandstones and conglomerates of the west were seen to be overlain unconformably by those very quartzites and limestones which Sedgwick and myself had observed to pass with a south- easterly dip under crystalline rocks constituting the great mass of the gneissic schists and micaceous flagstones of the central and eastern High- lands. The question then arose. What is the age of those quartzites and limestones which have a much less crystalline character than the rocks by which they are overlain? In the quartzites MacCulloch had, it is true, discovered minute organisms, which he classed with Orthoceratites, and which are now known to be the infilled borings of Annelids and small Crustacea. It was not, however, until Mr. Charles Peach dis- covered, in the limestones of Durness, clear and unmistakeable fossils of various sorts, which in the hands of Mr. Salter proved to be the Lower Silurian fossils to be noted hereafter, that I became possessed of the key which I had long sought for, and by which I was at once enabled to develope the whole order of the Horth-Scottish succession, from a Funda- mental Gneiss upwards, through Cambrian and Lower Silurian rocks, to the Old Eed Sandstone. Seeing that the fossiliferous limetones of Sutherland were by no means the oldest of the Silurian deposits of my classification (being of younger age than the whole series of the Lingula-fiags or “ Primordial [Silurian] Zone ” of Earrande), and that they reposed transgressively upon different members of the next underlying formation, or the red and purple hard](https://iiif.wellcomecollection.org/image/b28094360_0040.jp2/full/800%2C/0/default.jpg)
