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Disregarding for the present the small patch of Glenkiln Shales last described, it is evident that the strata of the Moffat series exhibited in the Main Cliff of Dobb9s Linn are naturally arranged in two main divisions palaeontologically distinct. Each of these divisions, again, falls naturally into two well-defined mineralogical subdivisions, each of which is, in turn, composed of several subordinate bands or zones, individually distinguishable by peculiar lithological and palaeontological features.

This genus was founded by Mr. Carruthers to include those compound forms of monoprionidian Graptolites in which the polypary is unilateral, growing from the initial point in one direction only. There can be no hesitation in regarding it morphologically as a branching Monograptus; its mode of development, the characters of its hydrothecae, and its geological distribution, all pointing unmistakably in this direction.

(1880). V.—On the geological distribution of the Rhabdophora. Annals and Magazine of Natural History: Vol. 5, No. 25, pp. 45-62.

On the 19th of last September there passed away from among us one of the most original and successful of the geologists of the century—Dr. Gustaf Linnarsson, the eminent palaeontologist of the Geological Survey of Sweden. His death was so sudden and so unexpected that his sorrowing friends have as yet hardly recovered from their grief and astonishment at the blow, and are not fully awakened to the magnitude of their loss.

In the neighbourhood of St. David9s, the Arenig rocks, described by Mr. Hicks in his paper read at the last meeting of the Geological Society*, are the earliest in which Graptolites are known to occur; and yet, when once they appear, so diversified are their forms that these Pembrokeshire rocks are only equalled, in the number and variety of the genera they contain, by the Canadian Graptolite-bearing rocks of equivalent age known as the Quebec Group. In more ancient deposits two species only, belonging to one of the two great sections into which these fossils are divided, have hitherto been detected, viz. Dictyograptus (Dictyonema) socialis , Salter, and Dendrograptus Hallianus , Prout. The former occurring in the lower portion of the Tremadoc rocks of North Wales, and the latter in the equivalent strata (the Potsdam Sandstone of America), it is impossible to say which genus is the earlier, or whether the group is first represented in Britain or in America. Before the discovery, in 1872, of the extensive series of Graptolites which characterize the Lower Arenig rocks of Ramsey Island, the Skiddaw Slates of Cumberland were supposed to be our earliest Graptolite-bearing rocks; but it is now known that the lowest rocks of the Arenig Group exposed in the vicinity of St. David9s, in which Graptolites abound, are of greater age than any part of the Skiddaw Slates yet described; and it is highly probable that they are also older even than the lowest beds of the Quebec Group known to contain

No sooner were these ancient strata studied in earnest by geologists, instructed by the world-renowned achievements of Murchison in Siluria, than what appeared to be clear and unmistakable proofs of a definite sequence were discovered. The earlier investigators soon recognized the fact that, when viewed upon a large scale, they dipped apparently N. and S. from an axial line running from Berwick to Dumfries. In the neighbourhood of this line they had a very ancient appearance, reminding the geologist of the strata of the Longmynd, which, in Siluria, rise out from below the base of the Silurian system. A further resemblance was found in the fact that they were similarly destitute of all traces of organic life. Precisely as in Siluria, the rocks which surmounted these barren beds in the south of Scotland were found to contain an abundance of the little understood fossils known as graptolites. These graptolite-bearing strata were subsequently ascertained to form the floor of the whole of the Uplands to the north of the unfossiliferous beds, except near the town of Girvan in Ayrshire. There certain limestones and schists were discovered, crowded with fossils, the majority of which were identical with those of the Caradoc formation of Wales, which was known to succeed the great graptolite-bearing Llandeilo formation of that country. To the north of these Girvan beds, higher Silurians were detected in the Pentland Hills and at Lesmahagow, crowded with Upper Silurian fossils, and passing upwards into rocks belonging to the succeeding system of the

The brief paper on the “Stratigraphical Succession of the Cambrian Faunas in North America,” communicated to Nature of Oct. 4, 1888, will have been read by British students of the Geology of the Lower Patæozoic Rocks with especial interest and satisfaction, as it puts an end to a controversy between European and American Geologists, and brings into harmony the sequence and palæontology of the Cambrian faunas on both sides of the Atlantic.

Cambrian of Westrogothia, Oland, etc.—The Cambrian Rocks are shown in several other localities in Scania. The basal sandstones (Lugnas or Eophyton sandstones) near the Baltic coast, near Delperöd. The Hardeberga sandstones (Fucoid Sandstone) are found wherever the Archæan is bared, as near Rostånga, Lund, Eljaröd, and Cimbrishavn. Sections of the Alum schists are rarer. The most perfect is that of Kiviks Esperöd on the Baltic, where the Coronatus Limestone or Exsulans horizon of the Parad. Tessini zone well developed. The identity between its palæontological sequence and that of Andrarum was demonstrated by Nathorst in 1876.

In those parts of Britain upon which all geologists are agreed with respect to the natural order of their ascending series of rock-formations, the stratigraphy is of a comparatively simple character. The beds are either gently inclined, or but slightly convoluted. The rules by which the original sequence of the strata is worked out have been settled by common consent. The nature and effects of those physical accidents which have affected the rocks subsequent to their deposition have long since been almost exhaustively worked out. The rules and conclusions thus developed are now-a-days part and parcel of the working material of every field-geologist worthy of the name.

This genus was founded by Mr. Carruthers to include those compound forms of monoprionidian Graptolites in which the polypary is unilateral, growing from the initial point in one direction only. There can be no hesitation in regarding it morphologically as a branching Monograptus; its mode of development, the characters of its hydrothecæ, and its geological distribution, all pointing unmistakably in this direction.

The Buchholm Sandstones.—These beds are characterized by the evidence they afford of having accumulated in shallow water. They consist generally of gritty greywackes and light green or red, sandy, incoherent shales and mudstones.

Summary of the Foregoing Evidences and Conclusions Respecting the Stratigraphy of the Girvan Succession (1)In the foregoing pages I have laid before the reader all the more important data obtainable in the geographical area under examination which bear upon the main question of the natural order of the Lower Palaeozoic rocks of the Girvan region. The original arrangement of the beds themselves has been so frequently interrupted by profound dislocations, and has been rendered so dubious locally by perplexing folds and inversions, that the task of reducing them to their natural order has been one of far more than ordinary difficulty. But so well are the several subformations in the collective series individualized by distinct petrological features, that the field-geologist has generally little hesitation in recognizing their entangled or dislocated fragments at a glance. At the same time also the foldings and inversions of the strata prevail only in certain definite geographical subareas, where they can usually be ultimately detected and allowed for. Finally, the greater faults are, as a rule, by no means difficult of localization, owing to the fact that they bring into abrupt and unnatural collocation upon the ground strata very distinct in their lithological and palaeontological features.Nevertheless the complexities and difficulties of the stratigraphy of the fossiliferous rocks of the Girvan region are so great that the solution of the problem of their natural sequence has been only arrived at by the accumulation of an excessive amount of evidence collected in the field. This evidence, however, is now so full, and so conclusive, that there can be no longer any doubt of the natural petrological subdivisions of the strata of the Girvan rocks, or of their true positions in the ascending succession. (2)The physical evidence, as developed in the preceding pages, in support of our conclusions may be summarized as follows;— (i)Selecting the remarkable Benan-Hill Conglomerate as our primary horizon of reference, we discover that it is merely the central member of a series (the Barr Series) of boulder-beds and conglomerates, with intercalary zones of limestone and fossiliferous shales. This series exhibits proofs of the most perfect conformity from base to summit, and its various members admit of minute and complete investigation in the field. This Barr Series includes the well-known Craighead or Stinchar Limestone as a subordinate member near its base, where it is divided from the underlying Ballantrae rocks by a calcareous conglomerate and breccia of irregular thickness. (ii)The tumultuous Barr Series is everywhere conformably surmounted, in the sections of the Girvan region, by a second series (the Ardmillan Series), composed throughout of Graptolitic flagstones and shales, which nevertheless arrange themselves naturally in several distinct subformations of well-marked petrological characters. The higher and lower divisions of this great series (the Ardwell, Barren Flagstone, and Drummuck Beds) have their respective systematic positions fixed by incontestible stratigraphical evidences. The proper relations of its central divisions (the Cascade and Whitehouse beds), the strata of which are usually inverted, are established mainly by geographical considerations. (iii)The Graptolitic series of Ardmillan visibly underlies a third series (the Newlands Series), consisting of Brachiopod-sandstones, Pentamerus-grits, and Monograptus-shales. The natural place of the first (Mulloch-Hill beds) division of this series is fixed beyond dispute by its relation to the terminal beds of the older Ardmillan series, and that of the highest division (the Camregan group) by its relation to the newer Dailly Series. The systematic position of the central division (the Saugh-Hill group) is deduced with equal certainty from its intermediary place in the series; but the sequence of the component strata of this central division is rendered so dubious by inversion, faulting, and local unconformities, that we are unable to give more than a provisional classification of its minor zones. (iv)Finally, we discern a fourth petrological series (the Dailly Series), at once the thickest and most homogeneous series in the Girvan succession. Its place at the summit of the whole is established by the circumstances that it forms a single series of similar strata, which is wholly distinct from either of the series below, while it lies on the southern (or upper) side of the Newlands Series, from the highest zones of which its strata appear to graduate in conformable sequence. (3)In place of an enigmatical group of Lower Palaeozoic rocks of no great vertical thickness, varying locally in their petrological characters to an extraordinary extent, and containing an admixture of fossils elsewhere characteristic of formations of several distinct geological epochs, as believed by some of the earlier students of these beds, we find an orderly arranged sequence of strata several thousands of feet in vertical thickness, grouped very naturally in successive formations of distinct petrological features, each formation retaining even in its subordinate zones the same characters over the entire area, and, as we shall show in the second part of this memoir, invariably affording the same special group of fossils. (4)In brief, our study of the stratigraphical relations of the rocks of the Girvan succession has fully established the following propositions:— i.The Girvan succession of Lower Palaeozoic rocks consists of a generally continuous series of more or less fossiliferous strata of a collective thickness of 7000 feet. ii.It is divisible into four main rock-formations, each of which is individualized by special petrological and palaeontological characteristics. iii.Each of these formations is, again, made up of several subordinate members, whose relations to the subformations above and below are beyond dispute, and which retain their special characteristics both in rocks and fossils wherever they are laid open for investigation within the district.The detailed classification of these Lower Palaeozoic strata of Girvan, as developed in the preceding pages, is given in the Table, fig. 31, pp. 660, 661. (5)These Girvan rocks appear to repose, at their base, upon the generally older igneous and altered rocks of Ballantrae. The Ballantrae rocks have, as yet, been too imperfectly studied to allow us to hazard any conclusion respecting their true geological age. That many of the rocks grouped together under this title are of far greater antiquity than the basement-beds of the Girvan succession may be regarded as established by the fact that fragments of the Ballantrae rocks occur in the Kirkland or Purple Conglomerate at the base of the Girvan sequence. These pre-Girvan traps and ashes must either represent the Arenig and Llandeilo volcanic rocks of Wales and Cumberland or must be of more ancient date. On the other hand, rocks which are unquestionably of true Girvan age occur at many localities within the typical Ballantrae region itself, while the patches of altered or so-called Ballantrae rocks found outside that area, as at Shalloch Hill, Laggan Hill, and elsewhere, almost certainly include some greatly altered Girvan rocks. (6)The sequence among the Girvan fossiliferous rocks is broken by at least one fairly distinct unconformability, viz. that at the, base of the Craigskelly conglomerate; but the presence of boulder-beds at the base of the Mulloch-Hill group, at the base of the Saugh-Hill Grits, and elsewhere, renders it exceedingly probable that other local stratigraphical breaks may eventually be detected.These local unconformities, however, can be of no great systematic importance; for the general gradation, both in sediments and fossils, from the base to the summit of the Girvan succession is practically complete. Each distinct petrological formation in the vertical series is connected with its neighbours, both above and below, by a group of beds intermediate both in physical and in zoological features. Thus the very distinct formations of the Stinchar Limestone and the Benan Conglomerate graduate into each other through the transitional zone of the Didymograptus-beds (Ab4), the Benan and Ardwell series through the transitional Balclatchie group, the Ardwell and Whitehouse beds through the intermediary Cascade beds, and so on. Even the two grand divisions of the succession, the Upper and Lower divisions of the Girvan rocks, are united by the intermediary formation of the Mulloch-Hill beds.The geographical distribution of the various members of the Girvan succession within the region we have described is given in the accompanying Maps and Plates, &c.The detailed description of the physical structure of the region, and of the lithology and palaeontology of the several members of the Girvan succession, together with the discussion of their resemblances, physical and zoological, to their extra-Girvan equivalents, are points deferred to the second part of this memoir.

I. Introductory. The Lower Silurian rocks of Scotland, largely developed as they are in the south, and in spite of the great labour that has been bestowed upon them, are by far the least known of all the fossiliferous formations of this country. While the maps of the Government Geological Survey are coloured in all the subdivisions of the strata of the other formations included in the area, the Lower Silurians are merely indicated by a common purple tint, and not the slightest attempt at a subdivision is made. Even the single bed of limestone they contain below the horizon of that of the west coast is doubtfully referred to the Llandeilo, and the sign of interrogation is carefully placed before its title. Nicol, Harkness, J. C. Moore, and many other eminent geologists, have worked different portions of these ancient deposits since the publication of ‶The Silurial System,″ but as yet very little progress has really been made in correlating its different parts with those of the type formation of the sister country. Now this want of accurate information is due to two causes: 1 st, The strata are so rapidly folded and contorted, and are consequently so intricate and confused, while at the same time they present so few differences lithologically, that anything like a physical separation of its masses is well-nigh impossible; and, 2 d, The whole formation, if we except of a few isolated bands of limestone towards the west, and some bands of anthracitic shale that make their

In the pages of the Geol. Mag., about a year ago, I called attention to the rapid growth of our knowledge of the sequence and fossils of the Lower Palæozoic Rocks of Sweden, through the brilliant discoveries of the officers of the Swedish Geological Survey; and pointed out what appeared to myself to be their special bearing upon certain controverted points in British Geology. During the past year the additional results obtained by the same group of earnest and unprejudiced observers are so important in themselves, and have been worked out with such care and elaboration, that we have now a tolerably complete view of the entire Lower Palaeozoic Succession in the Scandinavian Peninsula, and are, for the first time, in a position to attempt the detailed correlation of its recognized rock groups with their representatives in Britain.

In the year 1888 I published a short paper in the pages of the Geological Magazine and in “Nature,” in which I gave a brief account of the discovery of the fauna of the Olenellus (or Lower Cambrian) zone in the Comley or Hollybush Sandstone of Shropshire. Since that date great advances have been made in our knowledge of the Olenellus fauna of other areas, and the Olenellus zone has now generally attained an established rank and systematic position in the Geological Record as the basal zone of the Cambrian system.

The graptolites obtained by Mr Henderson from the shaly Silurian beds of Habbie’s Howe, and which I have had in my possession for determination, belong at least to three distinct genera. The most frequent fossil (marked 1 on the pieces of shale exhibited) is a peculiar form, which is usually held to be merely a variety of Monograptus colonus (Barrande). It differs from the typical form in several minor respects, such as the shape of the thecae, the direction of the apertural spines, the rate of taper in the polypary, c in the Wenlock rocks of South Roxburghshire, and in the Wenlock and Lower Ludlow of the typical Siluria. The variety under notice has been

Having gained a general comprehension of the probable physical and palæontological sequence among the Lower Palæozoic strata of the Southern Uplands of Scotland, as partly published in my memoirs upon the “Moffat Series,” and the Girvan Succession, I felt myself at liberty last summer to commence the study of those rocks of the North-west Highlands, which are supposed to be of corresponding age.

Charles lapworth was born in 1842 at Faringdon, in Berkshire. Five years afterwards his parents removed to Lower Newton, one of the farms rented by his grandfather. He attended the country school at Buckland village, about two miles off, and the vicar of the parish, the Rev. Joseph Moore, finding him an omnivorous reader, generously lent him books from his own library and practically directed his early education. At the age of 15 he became a pupil teacher in the school, and in the year 1862 entered the Training College at Culham, near Oxford, passing out thence in 1864 with a first-class Government certificate. Of the posts as schoolmaster which were then offered him he selected that connected with the Episcopal Church at Galashiels, because it would give him a home and work in the fascinating borderland of Sir Walter Scott. This post he retained for eleven years, and was married in 1869 to the daughter of Mr. Walter Sanderson.

The author began by calling attention to the fact that the geological framework of Scotland is essentially composed of rocks of Silurian age, which occupy almost the whole of the northern and southern divisions of the country, and form in the centre a comparatively small synclinal hollow or basin, which is filled up by deposits belonging to the later systems of the Old Red Sandstone and Carboniferous. It thus becomes one of the first problems in Scottish Geology to ascertain the order of succession among these Silurian strata, to endeavour to read the history of its life system, and in general to obtain means for a comparison of the formation with the Silurian of other countries. To this problem the crystalline and metamorphic rocks of the Highlands can never furnish the key, which must therefore be sought among the comparatively unaltered and more fossiliferous deposits of the Southern Uplands. Here, however, we are at once brought face to face with what seem at first to be insurmountable difficulties. There is an almost complete identity of mineral character throughout the whole series; there are great thicknesses of strata from which fossils appear to be wholly absent; and, to crown all, the beds have been thrown into such a multitude of wrinkles and plications, so disturbed and inverted, that it is impossible to say on physical evidence alone, in a traverse of any distance, whether we are ascending or descending in the order of the strata. With these obstacles in the way This 250-word extract was created in the absence of an abstract

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BY those accustomed to the hopeless confusion of the Greywacké of the earlier geologists, the publication of Murchison's grand work on the “Silurian System” was hailed with feelings of the most profound relief and satisfaction. His clear and brilliant presentation of the physical and palæontological proofs of an orderly sequence among the Palæozoic Rocks below the Old Red Sandstone, as originally set forth in all their force and harmony in his magnificent volumes, naturally astonished and dazzled the majority of his scientific contemporaries, and secured for his nomenclature of these ancient deposits an almost universal acceptance. His subsequent abuse of this advantage to strengthen and consolidate his own system at the expense of that of his equally - illustrious co-worker—the less fortunate but more cautious Sedgwick —was a gallant but unscrupulous defence of this original nomenclature, which by that time he must have felt himself almost powerless to disturb. His later extension downward of the limits of his system, till it embraced all the rocks between the supposed Azoics and the Old Red Sandstone—though, in a measure, forced upon him from without—ought perhaps to be regarded in part as a very natural return to the ideas of his early teachers, who had always held the practical unitly of the rocks of the Transitionalperiod. In this wey, however, Murchison unwittingly destroyed many of the most beneficial results of his won labours; in a sense, spending his old age in the attempted re-erection of the very edifice it hed been the pride of his manhood to destroy—the early years of his scientific career being devoted to the worthy task of proving the marvellous variety of the Lower Palæozoics; his later years to demonstrating their integrity, unity, and indivisibility.

Next to the metamorphic region of the Northern Highlands there is perhaps no area in Britain where the strata have been so contorted and convulsed as in the great Lower Palæozoic region of the Southern Uplands of Scotland, and it is only by the zonal method of stratigraphy that these complexities can ever be successfully unravelled. So far as the present results of the application of that method enable us to judge, it appears that, underlying all these stratigraphical complexities, there is, in reality, a broad tectonic structure of great simplicity. For, if we make exception, on the one hand, of the lowest strata (the Ballantrae or Arenig rocks), which, as we have seen, only rise to the surface within the limits of the Ballantrae district; and on the other hand of the highest formations (Wenlock-Ludlow), which merely skirt the Upland plateau upon its north-west and south-west flanks, we find that almost the whole of the Lower Palæozoic strata of the Uplands are naturally grouped in two grand lithological terranes, viz. (I.) a Lower Terrane (Moffat Terrane), including strata ranging from the Upper Llandeilo to the Upper Llandovery; and (II.) an Upper Terrane (Gala or Queensberry Terrane), embracing strata generally of Tarannon age.

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In his excellent paper on New Scottish Graptolites, published in the last monthly part of the GeologicalMagazine, Mr. John Hopkinson incidentally refers to the various opinions that have been held by different geologists concerning the thickness and geological age of the carbonaceous Graptolite-bearing shales of South Scotland. He expresses his conviction, derived from a study of the fossils they afford, that there is but “a single band of Graptolite shale, which runs through the Llandeilo beds of South Scotland, there being in this band several distinct zones, each marked by a different assemblage of fossils, but with many species in common.”

On the extreme north-west flank of the Lower Palæozoic region of the Southern Uplands of Scotland there occurs a remarkable coastal area of stratified, igneous and altered rocks, known to geologists as the “Ballantrae Rocks,” from the little fishing town of Ballantrae, which is built upon them. They range along the shores of the Firth of Clyde for a distance of about 12 miles, and are well displayed in section in a series of rugged cliffs cut through by the picturesque coast road between Ballantrae and Girvan. The area they occupy nowhere exceeds five miles in width, and is limited inland by the smoother regions floored by the barren greywackés of the Uplands and the fossiliferous strata of the Girvan district, but this inland boundary is everywhere curiously broken and irregular.

On the Graptolites of Gothland (Om Gotlands Graptolither). By G. Linnarsson. Ofv. af. Kongl. Vetens. Akad. Förh.; 1879, No. 5, pp. 12.The island of Gothland, so rich in all other Silurian fossils, is remarkably poor in Graptolites. Angelin and Lindström simply noted the fact of their presence, but did not attempt their identification. At Dr. Lindström's suggestion, Mr. G. Linnarsson here describes and figures the two species that have been procured from these strata, from examples now in the Riks-Musei of Stockholm.