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Dr Macculloch, it has always been considered as belonging to the secondary rocks, or at least to that class of secondary rocks to which some geologists apply the term transition. It is principally distinguished from the red sandstones of the centre of Scotland, by its extreme hardness, and by its crystalline texture. In this respect it often equals common quartz, no distinction between the constituent grains being visible, but the whole appearing as if cemented by a general solution of silica. It is often, however, in these cases, gravelly, while it occasionally consists of large fragments, angular as well as rounded, of different colours, compacted into one crystalline mass. It is always stratified. In the predominant examples, the strata are very thin and equal; and in all these cases the angle of inclination is low, deviating in some instances but slightly from the horizontal position; and the surfaces of the flags sometimes bear these marks of undulation which occur in the secondary sandstones, and resemble so much the marks left by the sea on sandy shores. Where the angle of inclination becomes considerable, the distinctness of the stratification diminishes; and where the beds assume the vertical position, it requires great care to discover any marks of that order; the rock acquiring the aspect of some granites, or that of the irregular gneiss by which it is accompanied, and being split into prismatic or angular fragments. Both in the islands and on the Mainland, it graduates into gneiss; and the transition is effected sometimes by schist, and grey indurated sandstone, and sometimes by quartz rock. In a large proportion, however, of the Mainland, no such transitions are found; but there is a sudden and complete alternation of the two rocks. The alternations with gneiss are visible at Loch Carron and Great Loch Broom; the sandstone in the latter place. lying beneath the gneiss, and both having a common dip to the south-east. It forms hills of all dimensions, and of every variety of aspect-round, conical, ridged, or serrated, alternately rising to the greatest average altitude of the Scottishi mountains. Kea Cloch, in Ross-shire, presents in itself exam.. ples of all these forms; the summits being in some places no less strongly serrated than those of the Arran mountains, while the height is between 3500 and 3700 feet; and, what is remarkable, the strata of this mountain are horizonal, and consist of the red sandstone from the base to the summit; and as it is separated by a wide valley from the adjoining mountains, which are composed of the same rock, it stands as an index of the enormous waste by which the land has been worn down into its present outline. VOL. XXXIII. NO, 66.
It is scarcely necessary now to say, that this sandstone must be ranked in the class of primary rocks. On no other view can the preceding facts be explained, notwithstanding the occasional points of resemblance which it presents to those of the secondary division. It must therefore be considered as a red primary sandstone ; and, that it is not even the latest of the primary strata, is evident from the preceding history of its connexions.
• No objection need arise with respect to the use of the term primary, as applied to a rock composed of the reunited fragments of former rocks. That term has here, as on other occasions throughout this work, been substituted for the word primitive, and is purely relative; implying nothing theoretical respecting the origin of any order of rocks, whether stratified or amorphous. Nor is this sandstone a solitary example of the mechanical recomposition found among rocks of the primary division. The instances of this structure occurring in the quartz rock of Jura and the associated islands, are equally remarkable; and there are indeed striking analogies between that series and the presenţ, in many important particulars. With respect to the existence of an unquestionably mechanical structure in a primary rock, it may also be remarked, that the micaceous schist of Isla, which contains fragments of granite and quartz rock, presents a decided example of it ; as do also those rocks of the graywacké and conglomerate structure, which are found among the argillaceous schists in various parts of Scotland. If even the red sandstone of this district be considered as a modification of quartz rock, no alteration will follow in the nature of any of the views that have here been brought forward. The same history will be transferred to a new term, not to another substance ; and the same consequences will follow, that so often result from the substitution of one word for another; in the best cases, that of leaving every thing precisely where it stood before ; and in the worst, confusion and obscurity, instead of light and order.'. II. 98, 99.
In further illustration of the important inferences to be deduced from this history of the primary sandstone, we may notice the occurrence of a conglomerated rock formed of fragments of quartz, imbedded in a micaceous schist, in the island of Coll --of a conglomerate composed of rounded and angular pebbles of quartz and gneiss, imbedded in a gravelly clay, found contained between two portions of gneiss in Lewis of a rounded pebble imbedded in the clay state of the Isle of Man-bat, above all, that most interesting discovery, of a rock containing organic remains alternating with gneiss, at Loch Eribol. It is scarcely necessary to point out how entirely these facts demonstrate the truth of that great and fundamental position of the Huttonian theory, the most important in its consequences in the whole range of geological inquiry,—That in all the
strata we discover proofs of the materials having existed as
elements of bodies which must have been destroyed before the
formation of those of which these materials now actually make "a part.' That Dr Macculloch coincides in those views, is sufficiently evinced by the following passage.
• With the exception of granite, it is not probable that geologists have yet discovered a rock beneath which organic remains may not be found. As they diminish in number, in a general sense, the further we recede from the most recent strata, it is plain that, among the lowermost rocks, they may occur so rarely as still to have escaped: observation ; a circumstance of which the chances would be increased by their more limited variety, more complete loss of texture and shape, and more simple forms. Their gradual disappearance in those cases where the secondary limestones assume the massive structure and crystalline texture, described in the account of Skye and of the Isle of Man will illustrate this opinion, and suggest the possibility, that even the common primary limestones may originally have contained organized bodies.
· Perhaps when observations have been further multiplied, it may yet be ascertained, that there has been no portion of time during the deposition of the stratified rocks, however ancient, in which animals have not existed. In concluding this subject, it is unnecessary to point out the importance of the preceding facts to geological science ; and it is almost superfluous to say, that to account for them by calling this gneiss a transition rock, is merely to substitute à term which leaves the fact and its consequences precisely where they stood before ' II. 514, 515.
The Schistose Islands comprehend Isla, Jura, the smaller isles immediately contiguous, and those which lie between Mull and the Mainland. Their strong resemblance to each other in structure, the obvious repetitions of similar strata which occur throughout them,- the mutual correspondence of their outlines and of the bearing of their strata, together with the intimacy of their geographical positions,—render this association as natural as it is useful for the illustration of the whole. They consist of all the primary stratified rocks except gneiss; and, among them, quartz rock and clay slate appear predominant, micaceous schist being less abundant. These are accompanied by a series of rocks composed of chlorite schist, of felspar, and of hornblende, in various states of mixture and alternation; and, lastly, by graywạcké and limestone, the last being the smallest in quantity. The same alternations of rock which occur in any one or more islands, are found also nearly throughout the whole group, although in different proportions. In contemplating these alternations, there is nothing more remarkable than the frequent change of substance, and the tenuity of the strata which are thus intermixed with each other; and, in consequence of this perpetual change, substances generally considered as occupying distinct places on the surface of the earth, in a regularly consecutive order, are here repeated without any distinction as to priority or posteriority; clay slate, for example, being sometimes found above and sometimes below micaceous schist, sometimes alternating with gneiss, as it also does in North Uist. In the island of Isla, the following series may be seen extending from the western side of the island to the Mull of Oe on the east; and they can be traced in contact and in obvious succession throughout the whole space: clay slate-gneiss-clay slate-graywacké slate-clay slate quartz rock-coarse graywacké quartz 'rock, clay slate-micaceous schist, clay slate. Numerous instances of similar alternations are mentioned throughout the work, affording abundant proof, if such were wanting, that the doctrine of Universal Formations and regularity in the order of succession of the strata, has been founded on very limited experience, and cannot be admitted as a general law. These examples are no less valuable in pointing out the fallacy of the theoretical division of rocks which are distinguished by the term transition.
Our remarks upon this work have already extended to so great a length, that we are unable to enter upon many points of great interest that have occupied Dr Macculloch's attention, as they would take up more space than we can allot to them. We are thus prevented from doing full justice to Dr Macculloch, by pointing out more particularly wherein he is entitled to the ho nour of original discovery, both in geological facts, and in having found many of the simple minerals in these islands, which were not previously known to exist there. But Dr Macculloch's reputation stands already so high, and his views are so much beyond those who would give battle about the discovery of a pebble, that we did not feel very anxious about the defence of his fame in this respect.
We have heard, with great satisfaction, that he has made considerable progress in a survey of Scotland, with the view of publishing a geological map. This important and very arduous undertaking is conducted under the direction of the Board of Ordnance, and, in conjunction with the great Trigonometrical Survey, does infinite honour to that Board; while it affords an eminent proof of the liberal and enlightened views of the illustrious Person who is now at the head of it, that' while he is conducting the national objects committed to his charge, the great public cause of Science is cherished and promoted.
Art. IX. A Guide to the Electors of Great Britain upon the
Accession of a New King, and the immediate Prospect of a New Parliament. Third Edition. 8vo. pp. 56. . London, Ridgway. 1820.
upon any political subject, as the one now before us. The publick having already pronounced a decisive opinion in its favour, by exhausting two editions during the bustle and distractions of a General Election, we may be thought to undertake a needless task in professing to describe its merits; but we owe it as a debt of gratitude to the author, for the light he has thrown upon questions highly important, and hitherto treated with vague and unprofitable declamation on the one side, or mysteriously wrapt up in the obscurity of official details upon the Other. The author is, we believe, pretty generally known to be Mr Crecvey, a Member of Parliament for many years; during which he so highly and so usefully distinguished himself as the friend of rational reforms, the advocate of sound constitutional principles, and the unsparing enemy of abuse, that his exclusion from the House of Commons must now be regarded as a serious publick loss; more especially at a period when those questions are to be brought under review, with which he, more than any other man, had shown himself intimately acquainted,
The beginning of a New Reign, as the reader probably knows, brings forward one of the most momentous subjects on which the representatives of the people can at any time be called to deliberate the formation of the Civil List, -that is, the arrangement of nearly the whole civil expenses of the country, including the charges of executing the Laws at home, representing it abroad, and providing for the support, the dignity, and the splendour of the Crown, In the ancient times of the Monarchy, the Sovereign, who was rather the first of the feudal Barons than the ruler of a great People, derived his revenues chiefly from land vested in him as a great proprietor, and from certain occasional perquisites given to him for the better support of his office; and, it may be added, that the services which his vassals were bound to perform in war, or to redeem with money, helped him mainly to defray its expenses. On extraordinary occasions, taxes were levied directly upon the subject; but the bulk of the revenue was that which the King derived from his Possessions and his Prerogative, independent of any consent of Parliament for raising it, and of any controul in its expenditure. In return for the funds thus vested in the Crown, it was