Secondary Rocks Research Articles

XXIV. On the radium content of secondary rocks

XXIV. <i>On the radium content of secondary rocks</i>

On the Glacial Origin of Huronian Rocks of Nipissing, Ontario

Previous articleNext article FreeOn the Glacial Origin of Huronian Rocks of Nipissing, OntarioReginald E. HoreReginald E. Hore Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 18, Number 5Jul. - Aug., 1910 Article DOIhttps://doi.org/10.1086/621759 Views: 41Total views on this site PDF download Crossref reports no articles citing this article.

Fossil Footprints in the Secondary Rocks

Fossil Footprints in the Secondary Rocks

The Flora of the Inferior Oolite of Brora (Sutherland)

The object of this paper is to place on record the discovery of a bed containing plant-impressions in the Oolites of Brora in Sutherland, which represent a flora bearing a strong likeness to that of the Inferior Oolites of the Yorkshire coast, and to give a short description of the Scottish plants. In Prof. Judd's (73) classic memoir on the Secondary rocks of Scotland, the description given of the district round Brora in Sutherland shows that it is the most favourable locality for studying the Secondary formations of the country. Near the little town of Brora the beds are well exposed, and are of economic importance on account of the workable coal and building-stone which they supply. It is not necessary to point out how little there is left in Scotland of the rocks of Oolitic age. Notwithstanding its inaccessibility, the Brora district had been referred to by geologists even before the time of Murchison, the coal-pit having been first sunk in the Oolitic coal in 1598 by the Countess of Sutherland. Repeated borings have been made since, and the mine, although stopped down in the early part, of the nineteenth century, is at present again in active work. This practically unique case of an extensive coal-mine in the Oolites has attracted the attention of geologists, yet remarkably little is to be found in the literature about the fossil-plants of the coal-bearing beds. In a paper by Hugh Miller (62) in his well-known book, some plant-impressions are mentioned, but most

The Rhætic and Contiguous Deposits of Glamorganshire

I. I ntroduction . I n the autumn of 1904 I made, in company with my friend, Mr. E. Talbot Paris, a detailed examination of the Rhætic and contiguous deposits of Monmouthshire and GLamorganshire. The results of my investigations in the former country have already been made known, and it now remains to record those in the latter. Less than four years have elapsed since the officers of the Geological Survey completed the re-survey of the Secondary rocks of Glamorganshire; and that part of the memoir on ‘The South-Wales Coalfield ’ which deals with the Bridgend district was only issued to the public last January. This being the case, it might be thought that but little of interest would have remained to be noticed in the present communication. However, whereas the officers of the Survey were mainly concerned in the mapping of the deposits, my attention was directed ill most cases to the accumulation of facts bearing upon the physical geography of the Rhætic Epoch. On a previous occasion I communicated to this Society a theory, to account for the geographical distribution in North-West Gloucestershire and Worcestershire of certain beds at the base of the Rhætic Series. I then stated that, ‘there is evidence to suggest that there were earth-pressures at work at the close of the Keuper Epoch, which caused the deposits to be thrown into slight synclinal and anticlinal flexures. In the depressed areas the earlier deposits of the Rhætic were laid down, and successive overlap on to the marls seems

III.—On the Lower Jaw of a Small Mammal From the Karoo Beds of Ariwal North, South Africa

In the collection of Mr. Alfred Brown, of Ariwal North, which I had recently the pleasure of looking over, I came across the right lower jaw of a small mammal which Mr. Brown had discovered in sandstone near Ariwal. Though unfortunately the teeth are lost, there is evidence of there having been a large canine. The most remarkable character of the jaw is its extreme shortness, and in its general proportions it agrees much more with the jaws of some of the small carnivorous Eutherians than with those of the small carnivorous or insectivorous genera already known from the Secondary rocks. The angle is well developed and but very slightly inflected. The condyle is practically in a line with the alveolar margin.

Overthrusts and other Disturbances in the Braysdown Colliery; and the Bearing of these Phenomena upon the Effects of Overthrust-Faults in the Somerset Coalfield in general

The Somerset Coalfield is a remarkable one in many respects. Unlike most of the larger coalfields of this country, by far the greater part is concealed by Secondary rocks, consisting of Oolites, Lias, and Trias, which lie almost horizontally upon the disturbed Coal-Measures beneath. Faults in these newer rocks are comparatively few and small. The Coal-Measures, however, present a marked contrast in this respect—for this coalfield is in part the most disturbed and contorted of those known and worked in the United Kingdom. Its area covers about 240 square miles, and it is presumably an isolated basin, bounded on all sides by anticlines of older rocks. On the north, in the Coal-Measures at Kingswood, near Bristol, there is an anticline and overlap-fault, which separates the Somerset Coalfield on the south from the Bristol or Gloucestershire Coalfield on the north, on the borders of which the margin of older rocks is clearly defined. On the south and south-west the great Mendip anticline separates it possibly from a similar coalfield, concealed beneath the thicker Secondary rocks on the farther side of the Mendip Hills; and on the east, the anticline which passes from the far north near Cromhall, in Gloucestershire, through or near Yate, probably continues slightly to the west of Bath and thence to Frome on the south. The object of this paper is an attempt to describe the overfaults and related phenomena in a single colliery, namely that of Braysdown, near Radstock, and to show how the conclusions that may

On the Eastern Limits of the Yorkshire and Derbyshire or Midland Coalfield

The Author attempts to throw light on the question of the easterly extension of the Yorkshire, Derbyshire, and Nottinghamshire coalfield beneath the newer rocks. He notices the general trend of the strata, the sizes of other British coalfields, the question of the origin of mountains, stratigraphical considerations, and the faults of the North of England. His object is rather to suggest what he believes to be novel ways of treating the subject than of reaching conclusions or locating limits. The Author calls attention to the previously established fact that an anticlinal exists in the Secondary rocks near the southern end of the Lincolnshire Wolds. The existence of this anticlinal has been demonstrated by Mr. A. J. Jukes-Browne (Quart. Journ. Geol. Soc. vol. xlix. 1893, p. 467). Following the reasoning of M. Marcel Bertrand, he infers that an anticlinal in the Carboniferous rocks probably underlies this, and that the easterly termination of productive Coal Measures under Lincolnshire may be formed by this anticlinal.

On Overthrusts of Tertiary Date in Dorset

I. I ntroduction The intensity of the earth-movements which have thrown on end and inverted the Secondary rocks of Dorset, and the magnificent dissection of the structures in the sea-cliffs, have attracted attention for many years past. The first to give an accurate account, and to speculate on the causes of the position of the strata, was Webster in 1816; though admirable in his description and in his pictorial representation of the facts, he failed in his endeavour to explain them, and was in this respect improved upon by Conybeare and Phillips in 1822, and by W. B. Clarke in 1837. In 1830 Buckland and De la Beche read their paper on the Geology of Weymouth, etc., and gave an account of the principal faults, but did not correctly distinguish those that were formed before the deposition of the Gault from others that were produced at a later date. In 1848 a cutting made for the Dorchester and Weymouth railway revealed unsuspected complications in the great Ridgeway disturbance, which were described with great accuracy by Weston in 1848 and 1852, while additional light was thrown upon the subject by the publication in 1850 of the Geological Survey map, Sheet 17, in the preparation of which Bristow received great assistance from the Rev. O. Fisher. Further speculations on the age of some of the disturbances were made by Prof. Prestwich in 1875, and the existence of two distinct sets of movements was pointed out by Mr. Hudleston in 1881 and 1889. In

The Purbeck Beds of the Vale of Wardour

I. Introduction Although the Purbeck Beds of the Vale of Wardour have been noticed by many observers, and portions of them have been described by many writers from the time of Fitton downwards, no complete description of the whole series has yet been attempted, and a connected account of the Wiltshire Purbecks seems therefore to be a desideratum in geological literature. Fitton gave some account of them in his classical memoir ‘On the Strata between the Chalk and the Oxford Oolite,’ published in 1836, mentioning quarries at Dallard's Farm, Dashlet, Chicksgrove Mill, and Wockley; but since his time the Wockley quarry has been cut back, so as to expose the beds which were then only visible at Chicksgrove. He made no attempt to establish any succession, and thought the total thickness of the series was not more than 60 feet. The Rev. P. B. Brodie, in 1845, published a little book entitled ‘ A History of the Fossil Insects in the Secondary Rocks of England’ in which he gave some description of the Purbect Beds of Land’ in which he gave some description of the Purbeck Beds of the Vale of Wardour, and especially of two beds of limestone, one of which he called the ‘Isopod Limestone,’ because it contained Archœniscus , and the other the ‘Insect Limestone,’ from the abundance of insect-remains in it. Unfortunately, his reference to localities was not very explicit, but it is certain that the quarries “not far from the village of Dinton,” where he saw

On a Neuropterous Insect from the Lower Lias, Barrow-on-Soar, Leicestershire

So much attention has been bestowed of late years on fossil organic remains from rocks of all ages, that it must appear surprising to find so little notice has been directed to the Insectremains from the British Secondary rocks.It is now nearly fifty years since that veteran geologist, the Rev. P. B. Brodie, M.A., F.G.S., published his modest little 8vo. volume entitled “A History of the Fossil Insects in the Secondary Rocks of England” which is still the only separate work of the kind extant. Numerous Insect-remains have, it is true, been described by Prof. J. O. Westwood, Mr. H. E. Strickland, Prof. J. F. Blake, Mr. A. G. Butler, and Mr. S. H. Scudder, from English rocks of Secondary age; and Mr. Herbert Goss has given an excellent summary of our knowledge of the Mesozoic Insects in the Proceedings of the Geologists' Association (1879).

On Agrosaurus Macgillivrayi (Seeley), a Saurischian Reptile from the N.E. Coast of Australia

In July 1879 the Geological Department of the British Museum obtained by purchase from Mr. E. Charlesworth some fossil bones, which were dispersed at the sale of the collection of Mr. S. L. Waring, F.G.S., of Norwood, then recently deceased. They are labelled, in a small, delicate handwriting, “‘Ply,’ 1844. Jn. Macgillivray, from the NE. coast of Australia.” I believe this to indicate that the specimens were collected by Mr. Macgillivray during the voyage of the ‘Fly,‘ from some locality which was then unnamed. The bones were placed in the Mammal Gallery, where they have since remained. They comprise a complete left tibia, a less perfect proximal end of the corresponding right tibia, a fragment which I regard as a portion of a fibula, attached to matrix, which besides other fragments of bone contains two laterally compressed claw-phalanges. There is necessarily no direct evidence of their geological age. But as they indicate a new Saurischian reptile, which has its nearest known allies in the lower Secondary rocks of Europe and the Trias of South Africa, it is not improbable that the animal belongs to the Lower Oolites or Trias. I have not noticed any reference to the specimens by Professor Jukes in the “ Voyage of the ‘Fly’” or in his other books and papers, or in the writings of Mr. Macgillivray. The left tibia (figs. 1, 2) is about 20 cm. in extreme lengthy with the usual sub-triangular flattened proximal articular surface. That surface is nearly 5 cm. deep

On the Dentition of Lepidotus maximus , Wagner, as illustrated by Specimens from the Kimeridge Clay of Shotover Hill, near Oxford

The specimens upon which this paper is founded were obtained by one of us (Mr. Henry Willett) from the Kimeridge Clay of Shotover Hill, and at no great distance from each other, although at different times—two in the spring and one in the autumn of 1887, and the fourth in the spring 1888. The size and perfection of these specimens are alone sufficient to warrant their being brought under the notice of the Society; but, besides this, one of them appears to represent a distinct species, probably new to England, if not also to the Kimeridgian fauna of France. The species of Lepidotus known in England are as follows:— Section L eptoganoidei Suborder L epdosteoidei The Lepidosteoid Fishes range from the Permian to the present day. They are represented in the Permian rocks by the genus Acentrophorus . The following genera range through the British Secondary rocks:c Many species of Lepidotus attain a large size. Lepidotus maximus , Wagn. (= Sphœrodus gigas , Ag.), from the Lithographic Stone of Solenhofen in Bavaria, measures over 5 feet in length and 2 feet in depth of body; while L. Mantelli , Ag., from the Wealden Series (Hastings Sand) is nearly, if not quite, of equal dimensions. The similarity of the teeth in Sphœrodus and in the larger species of Lepidotus (such as L. maximus ) induced Agassiz to abolish the latter genus (but with hesitation) in 1869. Prof. Owen, however, from the microscopic structure of the teeth, regarded the two genera as distinct. On the other hand, many continental palæontologists

The salt deposits of Stassfurt

I. The physical map of Germany shows the country to be roughly divisible into two areas, one of which is mountainous, and the other comparatively flat. The southern or mountainous region contains several ranges, which have, as a rule, a north-westerly and south-easterly trend. Among these are the Thuringer Wald, Fichtelgebirge, Kyffhauser, and the Harz, which latter is the highest and most northerly member of the group, reaching in the Brocken an altitude of 3746 feet. The Erzgebirge, Mittelgebirge, and Riesengebirge form a separate and nearly continuous chain in the south-eastern part of Germany, and, unlike the other ranges, trend in an east-north-east and west-south-west direction. A vast flat or slightly undulating expanse, with few hills to relieve its monotonous horizontality, sweeps away northwards from the base of the Harz Mountains to the sea at Hamburg, and eastwards to the Baltic and the Russian frontier. It has been named the North German Plain or Norddeutsche Ebene, as our kinsmen of Deutschland would prefer to designate it, and is for the most part covered by deep drift, which overlies immense tracts of soft secondary and tertiary strata. The palaeozoic mass of the Harz rises through the secondary rocks in the form of a ridge about fifty miles in length, and fifteen or twenty miles in breadth, on either side of which are great flat troughs, filled with the newer formations. The northern area has been named from two of its principal towns, the ‶Magdeburg-Halberstadt Basin,″ while the southern, which extends between

The Origin of the Scenery of the British Islands 1

The Origin of the Scenery of the British Islands 1

The Evolution of the Cryptogams 1

II. THE direction and many of the gradations through which the highest classes of the vegetable kingdom have been developed from the lower are preserved in the palæontological record. In order to decipher them, however, certain facts must be kept in view: chiefly, that the higher and more complex organisations, are the most susceptible to changes in the external conditions upon which they are dependent, and therefore more readily destroyed, while the simpler the organisation the more yielding or plastic it is, and the greater the chance that it will be able to survive by adapting itself to change. Thus the superb Cryptogams of the Carboniferous succumbed no doubt to great physical changes, but the more humble of them bent to the new conditions, and even found abundant in the Trias and Secondary rocks, and to be analogous, or perhaps identical, with the existing Cymo-polia and Acetabularia. It is unfortunate that, owing to the texture of most of the Algæ, observation has to be concentrated on the few groups that could be preserved. In the Silurian the remains of these are numerous, and of forms completely differing from existing types.

II.—Contributions to the Palæontology of the Yorkshire Oolites

It is not proposed to discuss the merits of the generic name applied to a group of Univalves so characteristic of and so abundant in the Jurassic rocks. Melania, Eulima, and Chemnitzia have each of them served in turn, and in adopting Chemnitzia after D'Orbigny, the late Dr. S. P. Woodward observed that the “Melaniœ” of the Secondary rocks are provisionally referred to this genus. Pictet and Campiche include the Chemnitziœ and Phasianellœ of the Oolites in one genus Psendomelania, thus preserving to a certain extent the old generic appellation.

On Rhamphocephalus Prestwichi , Seeley, an Ornithosaurian from the Stonesfield Slate of Kineton

Prof. Prestwich as obtained from the Stonesfield slate of Kineton, near Stow-on-the-Wold, a small slab which makes a valuable contribution to our knowledge of the structure of the skull in Ornithosaurs from the British Lower Secondary rocks. This specimen is little more than a cast from the upper surface of the cranium, not unlike in general character to the form originally described by Goldfuss as Ornithocephalus Münsteri . The skull itself was unfortunately in the corresponding slab, which has not been preserved; but a few slight fragments of bone remain sufficient to show the dense osseous tissue which is usual in Pterodactyles. The specimen yields a clear impression, which displays the proportions of the cranial bones, and the sutures between them, in a way so distinct as to enable me to state that this animal was certainly different generically from every other type which has hitherto been described. Whether, however, it pertained to a distinct species from those indicated by the fossils from Stonesfield which have already been figured by Professors Huxley and Owen is a matter upon which some doubt may be felt; but bearing in mind the relatively large size of the jaws and teeth in those fossils, I am strongly of opinion that this specimen indicates a smaller kind of animal, in which the dentary apparatus was less developed, and I therefore venture to suggest for it a specific name. The remarkable feature which leads me to consider this specimen to be the type of a new genus

On some undescribed Comatulæ from the British Secondary Rocks

My work on the Comatulæ of the ‘Challenger’ Expedition naturally led me to a consideration of their fossil representatives; and I found that although continental palæontologists have described several species from the Jurassic and Cretaceous rocks of Central Europe, hardly one has been recorded as occurring in the corresponding formations of the British area. It soon appeared, however, that this is not because we have none to record, but merely because neither descriptions nor names have been given for those which we have. In the following pages I propose to make good this deficiency; but I would first express my sincere thanks to Mr. Etheridge, of the Royal School of Mines, to Professor Hughes, of Cambridge, and to Messrs. Henry Woodward and R. Etheridge, jun., of the British Museum, for the ready kindness with which they have allowed me to make use of specimens in the collections under their charge. I am also greatly indebted to Dr. Wright, of Cheltenham, for placing at my disposal two specimens from his own collection. Schlüter* has recently published some descriptions, together with excellent figures, of several new fossil Comatulæ from Germany, Italy, and Sweden. At the same time he has expressed some views as to their anatomy and classification which are inconsistent with some of his statements of fact, and still more so with the results of my own observations on the anatomy of the recent species. He gives the following general description† of the “Knopf” or centrodorsal piece, which is the part

The Secondary Rocks of Scotland. Third Paper. The Strata of the Western Coast and Islands

C onclusion . Although, as I have before stated, it has been thought advisable to postpone the discussion of the numerous problems of interest which suggest themselves to the student of the remarkable relics of the Secondary rocks in the Scottish Highlands, until the fourth and concluding portion of this memoir is published—yet there are several questions which at the present time engage the minds of geologists upon which, as it appears to me, the facts and arguments of the present part of this memoir have an important bearing; and these it may not be undesirable to notice briefly at the present stage of the inquiry. Other and more general discussions will be allowed to stand over till such time as I have made the proposed comparison between the characters and modes of preservation of the beds under consideration and those of their equivalents in Ireland, England, Scandinavia, and other portions of the Continent. I may briefly point out in the first place the great interest which attaches to the fact that there exists in the north-western part of the British archipelago a series of strata of Cretaceous age exhibiting evidence of the prevalence of estuarine alternating with marine conditions. The great and deserved amount of attention which is now directed to the similar beds, developed on such a grand scale in Western America, renders the discovery of the minute Scottish representatives of the period particularly important at the present time. It is tantalizing, however, to the British geologist to have to