bluuebunny/crossref_metadata_2025_split huggingface dataset:
Notes on the Structure of an Early Dictyonema.
Authors: Bulman O. M. B. 
Published: May 2009

SummaryThe more important points in connexion with the structure of D. flabelliforme are:—1. The absence of any real approach to the spiral arrangement of the thecae along the stipes.12. The absence of a common canal; and the consequent budding of each hydrotheca direct from the preceding one.13. The initial constriction of each hydrotheca cavity.4. The budding of the bithecae from the sides of the hydrothecae along which they lie.5. The early stage at which the presence of the bithecae is observed.6. The derivation, indifferently “right-handed” or “left-handed” of the crossing canal.7. The nature of the dissepiments—hollow bars derived principally as outgrowths of the bithecae.
The Petrography and Correlation of the Surface Deposits of South-east Devon
Authors: Shannon W. G. 
Published: May 2009

Summary of the ConclusionsThe petrography of the Plateau Deposits has been determined. They yield species both of local origin and of the general Haldon types.The kyanite and staurolite present have been derived from the north.The planation of the limestones was initiated during the Cretaceous period.The raised beaches are of slightly different types, the Thatcher raised beach being later. They furnish evidence of a former greater thickness of the Plateau Deposits.Modern beach deposits furnish some evidence of the distributive powers of certain minerals, and point to the existence of Triassic and Cretaceous sediments outside the Bay.
Is the Chalk a Chemical Deposit?
Authors: Tarr W. A. 
Published: May 2009

The composition of chalk has been shown to consist dominantly of three types of material, in the order of their importance, (1) amorphous, or extremely fine-grained material, (2) spheres, and (3) organic remains.The first, the writer believes, represents chemically precipitated calcite and aragonite, the second a chemically formed oolite, and the last the normal organic constituents.Recent studies have shown that the surface waters of the ocean in favourable localities are saturated with CaCO3 and that variations in amount of CO2 mean either solution or precipitation. It is believed that the physical conditions of the Cretaceous sea favoured precipitation. Bacteria may have been a contributing factor.It is hoped that the above suggestion of the possible chemical origin of a part of the chalk (the larger part) will cause those who have the opportunity of study to apply it further, for until the great amount of extremely fine material is accounted for the origin of chalk is not settled. The writer regards the chemical origin with favour because it seeks to explain the origin of chalk in the light of present knowledge of the precipitation of calcium carbonate from sea water.
III.—On the Original Form of Sedimentary Deposits
Authors: Blake J. F. 
Published: May 2009

The form of the deposits that are taking place on the sea-bottom at the present day is one of the essential elements required to be known when we wish to interpret the submarine contours, as throwing light on the submergence or elevation of the land in late geological times, or when we propose to use the variation of thickness of the strata deposited during any epoch as an indication of the position of the shore-lines at that time.In the case of deposits in small or temporary masses of water, their form and arrangement may sometimes be observed directly; but in the case of the deposits in the sea, where we can neither remove the water nor make borings beneath it, we can only avail ourselves of theoretical considerations.It might have been expected that the original form of various sedimentary deposits would have been considered in detail long ago, but as a matter of fact the few writers who have touched upon the question have mostly been content with the assumption that deposits taken as a whole are thickest near the source of supply, and the figures given in illustration of the arrangement of various kinds, and thereby the shape of each, are remarkable for their variety.As the theoretical results at which I have arrived differ fundamentally from the ordinary assumptions, it is to be hoped that some one will be able to point out the fallacy, if any, which has led me astray, and to explain more satisfactorily the observed features which appear to confirm the theory.
IX.—Note on an Unmapped Toadstone Bed in the Derbyshire Mountain Limestone
Authors: Moore Samuel 
Published: May 2009

In the Summer of 1901 I found in a pasture, between Oxlow Rake and Cop Round (IX S.E.), some blocks of Toadstone in a bed of clay that has all the characteristics of decomposed Toad-stone. The clay was being dug for puddling a new mere, and the deposit is well known to natives. I traced the outcrop south-west to Starvehouse Mine, and my inference that the clay was decomposed Toadstone was soon verified by the Toadstone itself coming to day-light and replacing the clay. I did nothing more that year, but in the Summer of last year I continued to follow the bed, and have traced it as far as Bushy Heath House (XV N.E.), a distance of about two miles from its starting-point.The outcrop starts as a clay bed, at the southern end of an enclosure called Old Moor (IX S.E.), at a point about 50 yards south-east of two old mine shafts, and where a spring issues from under the limestone scarp, at a height of 1,400 feet above mean sea-level (by aneroid). Thence it runs in a general south-west direction for half a mile, along a line of five springs at the base of the limestone escarpment, to the north wall of Starvehouse Mine (IX S.E.), which it cuts at an altitude of 1,500 feet.There is no throw at the Starvehouse lode, and the bed contours round the point of Cop Round and crosses Dick Lane 30 yards from the summit gate (1,510 feet); from there it runs south-east with the dip of the limestone to Moss Rake (IX S.E.), the base passing just above the letter n of Piece Barn on the map. It reaches the lode at 1,350 feet.
VI.—The Use of a Geological Datum
Authors: Thompson Beeby 
Published: May 2009

A proper interpretation of some geological phenomena requires that allowance shall be made for differential earth-movements that have taken place since the period of occurrence of the events or conditions under consideration.Present differences of level in rocks of the same age may be partly due to actual differences in depth of the sea-floor on which they were deposited, but they may also be the results of subsequent differential earth-movements either of a regional or of a local character, the latter including ‘fauhs.’In order to estimate the amount of displacement or differential movement, it is necessary to select a particular rock as a datum. The rock selected should combine, as far as possible, the following characteristics:—1. It should be comparatively thin.2. It should have a considerable horizontal extension.3. It should combine similarity in physical characters and palæontological contents over a large area, so that uniformity of depth of deposit may be postulated.
II.—A New Carboniferous Arachnid
Authors: Pocock R. I. 
Published: May 2009

Last April Dr. Anton Friê, of Prague, applied to the Natural History Museum for the loan of a fossil Arachnid which he had seen during a short visit to London in the Summer of 1902, and wished to include in a descriptive monograph of Carboniferous Arachnida which he has now in preparation. Since the specimen is unique, it was unfortunately impossible to accede to the request. Dr. Smith Woodward, however, kindly suggested that I should examine the specimen and, if necessary, describe and figure it, so that perchance an account of it might yet be in time to find a place in the monograph above referred to. The specimen, imbedded in the two pieces of a split nodule of clay-ironstone from the Carboniferous measures at Coseley, near Dudley, belonged formerly to the collection of Mr. Henry Johnson. It bears the register number 1551, and is ticketed by Dr. H. Woodward “Eophrynus, sp. nov.” The dorsal surface is exposed, part of it adhering to one face of the matrix, part to the other.1.—Description of the Specimen; its generic and specific features.The carapace unfortunately is crushed, and nothing positive can be affirmed as to its structure save that it appears to have been slightly wider than long, with a shallow, postero-lateral constriction and a straight, transverse, posterior border. In the middle line behind, however, there is an acutely angular impression, obviously representing the median impression occupying the same position and presenting much the same form in Eophrynus prestvicii, H. Woodw. The crushed condition of the carapace suggests that its median area was axially elevated as in the last - mentioned species and in Kreischeria wiedei.
IV.—The Circular form of Mountain Chains
Authors: Lake Philip 
Published: May 2009

I am a stranger in the field of speculation, and am quite unacquainted with the intricacies of its authorized boundaries. It is therefore with some hesitation, lest I should tread upon forbidden ground, that I venture to offer a suggestion on one point in Professor Sollas's paper on “The Figure of the Earth.”It has long been observed that mountain ranges and chains of islands (which, indeed, are only mountain ranges partially submerged) are generally curvilinear in form, but Professor Sollas is, I believe, the first to show clearly that the curve often coincides almost exactly with an arc of a circle. Such a mountain chain is frequently defined along its convex margin by a great reversed fault over which the mountain mass has slid forward; and in these cases, at least, we may safely adopt Suess's conception, and look upon the chain as the crumpled edge of a ‘scale’ of the earth's crust which has been pushed forward over the part in front of it. The surface along which the movement has taken place is called a thrustplane. If this surface really is a plane, then the edge of the ‘scale’, that is the mountain chain itself, must necessarily be circular in form; for if any plane cuts a sphere, in any position whatever, the outcrop of the plane on the surface of the sphere will always be a circle. There can be no deviation from the circular form unless the ‘sphere’ is not truly spherical, or the ‘thrust-plane’ is not a true plane.
III.—Fossiliferous Oldhaven Beds at Ipswich
Authors: Bassett Henry 
Published: May 2009

In the “Geology of the Country around Ipswich, Hadleigh, and Felixstowe” Mr. Whitaker drew attention to the probable existence of Oldhaven Beds at Ipswich. On p. 11 he gives particulars of a section in Stoke brickyard. Below the London clay at this spot occurred fine buff sand separated from the Clay by a thin pebble-bed containing fragments of shells. The buff sand was doubtfully referred to the Oldhaven Beds, while it was thought that the pebble-bed should also be included with these rather than regarded as a basement-bed of the London Clay. Below this doubtful Oldhaven sand occurred sands and mottled clays of the Reading Series. It was shown in the memoir that this pebble-bed occurred over a great part of this district with an outcrop along the valleys of the Gipping and the Brett. As a rule it rests on sands referred to the Reading Series, and is classed by Mr. Whitaker sometimes as basement-bed of the London Clay and occasionally as Oldhaven Beds.Recently in Ipswich I came across a very clear section of these beds in one of the brickfields, and as they here show a rather unusual facies it seems worth while to draw attention to the section, especially as the beds contain many fossils at one spot. The section occurs on the north side of Messrs. Bolton & Laughlin's brickfield between the Norwich and Henley Roads. The brickfield is situated almost due north of Brook's Hall, and about 100 yards south of the railway line, but apparently at the time of the Geological Survey there was no brickfield at this spot; the pebble-bed, however, was shown in another pit (which still exists) a little further westward, and was included in the basementbed of the London Clay by Mr. Whitaker.
VI.—Notes on the Witwatersrand Beds, Transvaal
Authors: Hatch Frederick H. 
Published: May 2009

In discussing a paper by Mr. J. S. Curtis on the Witwatersrand Gold Deposits, Mr. George Denny has raised the point that the slates or shales of the Witwatersrand, which especially characterise, but are not confined to, the Lower Witwatersrand Beds (Hospital Hill Series), are not of sedimentary, but of igneous origin. He relies chiefly on the fact that he has observed in places that a so-called band of slate cuts across the bedding of the quartzites. I think we are all prepared to agree with him that, where he can point out that this occurs, the rock which traverses the bedded formation must be an igneous intrusion; but such cases are rare. In the vast majority of sections where the slates are exposed, they are found to occur truly bedded, and in conformable relation with the quartzites with which they are associated. It seems to me that, after all, this is in the main a petrological question, which can be easily settled by the examination of the rocks in question under the microscope.With this end in view I have examined a number of thin sections of these rocks, in all cases prepared from the cores of boreholes, on account of the difficulty of obtaining near the surface specimens sufficiently fresh and unweathered for microscopic examination; and I have selected geological horizons which are well known on the Witwatersrand. They are (1) the band of slates which occurs in the neighbourhood of the Bird Reef Series, and (2) the slates which occur in the footwall of the Main Reef itself, in both cases in the eastern portion of the Witwatersrand, as at Van Ryn and Geduld.
III.—Further Notes on the Mammals of the Eocene of Egypt
Authors: Andrews C. W. 
Published: May 2009

Among the collections now in Cairo I find several new mammals, the remains of which have been collected by Mr. Beadnell, for the most part during the last few months. Brief descriptions of these new forms are now given in order that the names may be included in the lists in Mr. Beadnell's forthcoming report on the geology of the Fayûm area.Pterodon macrognathus, sp. nov.This creodont is known from the nearly complete left ramus of the mandible. The last molar, the first premolar, and the incisors are represented by the alveoli only, but the other teeth, with the exception of the canine, the crown of which is broken off, are in fairly good condition. The mandible is long and narrow from above downwards, the distance between the last tooth and the condyle being remarkably great. The transversely elongated cylindrical condyle is about on a level with the alveolar border, and is separated from the prominent angle by a deep notch; the coronoid region is imperfect.
II.—An Eocene Outcrop in Central Africa
Authors: Lelean Captain P. S. 
Published: May 2009

At the heart of Africa lies a vast area, so remote, so inaccessible, and hence so little known, that for the explorer it possesses a fascination all its own. The interests of the geologist have perhaps received less recognition than those of his fellow-scientists from the pen of the traveller; and there must be much that he would wish to know lying hidden in these distant regions awaiting discovery and publication. There is thus an encouragement to make known any facts which may throw light upon the geological structure of those parts, however small the contribution may be.While serving recently with the Anglo-French Boundary Commission (Niger-Chad) we found an outcrop of a fossil-bearing stratum in the region of the Sokoto, having, as shown in the accompanying map, giving its latitude and longitude, a position near the verge of the Great Sahara Desert. On my return, the specimens secured were submitted to the palæontologists of the British Museum, one of whom, Dr. F. A. Bather, has kindly drawn up the description which follows in a separate paper. For me it only remains to give a few particulars of the general and localized formation to supplement his account.Generally, the country consists of sandy plains, roughly estimated as lying some 500 or 600 feet above sea-level. These plains are traversed by watercourses, which contain running water only for some five or six weeks in the year, the rainfall of 535 mm. lasting during three months. A permanent water-supply is obtained by deep wells, which in some places reach a depth of 400 feet before tapping a constant source.
III.—The Gavarnie Overthrust, and other Problems in Pyrenean Geology
Authors: Dixon E. E. L. 
Published: May 2009

Of the places where undidtrubed limestone trested on older rocks, the most important visited by us was the valley of Hount-Sainte on the Spanish slope. This does not appear to have been considered by Carez, nor to have been hitherto described in detail. The fololwing sequence is clearly exposed, in descending order:—4. Palæozoic—Devonian and Carboniferous according to Bresson. Shales and limestone in the lowest part, the base evidently a plane of disturbance.
IV.—On some Dry Chalk Valley Features
Authors: Chandler R. H. 
Published: May 2009

The existence of a ‘wind gap’ or ‘pass’ at the head of a dry dip valley clearly points to the former extension of that valley beyond the present escarpment; and the depth of the gap is a measure of the size of the valley before being beheaded by the recession of the escarpment. Thus the gap at Merstham is about 300 feet deep, and the valley would probably have continued south some miles on to the Wealden uplands; the floor of this valley falls regularly north, and presents all the features due to a stream flowing in that direction previous to the formation of the Gault strike valley. As an instance of a less developed beheaded valley, the Maplescombe valley, which joins the Darent valley on the right bank at Farningham, may be instanced. The Maplescombe valley has a ‘wind gap’ of possibly 100 feet deep, and so its former southward extension would not have continued into the Wealden area as far as the Merstham valley; moreover, the floor does not slope regularly to the Darent, but is steepest at the head, the distance between each contour-line increasing as one descends the valley, viz.—The present valley floor, particularly the upper part, is evidently not the one down which a stream from the Weald would have flowed, for at the above noted rate of increased slope the valley would ‘run out’ (or become extinct) at a very few hundred yards south of the present Chalk escarpment, and this short length is not compatible with the excavation of a valley 100 feet deep, such as the present wind gap.
I.—The Sculpturings of the Chalk Downs of Kent, Surrey, and Sussex
Authors: Clinch George 
Published: May 2009

The aim of this paper is to offer an explanation of the phenomena intimately related to the sculpturings of the Chalk Downs in the district under review, namely:—(1)The Dry Chalk Valleys.(2)The River System of the Wealden area, as far as it relates to the Chalk Downs.(3)Incidentally, the Denudation of the Wealden area.
VI.—On the Stratigraphical Distribution of the Inferior-Oolite Vertebrates of the Cotteswold Hills and the Bath-Doulting District
Authors: Richardson L. 
Published: May 2009

Vertebrate-Remains are by no means abundant in the Inferior-Oolite rocks of the Cotteswold Hills and Bath—Doulting Distriet. Mr. H. B. Woodward, F.R.S., has written—“The Inferior Oolite Series has yielded a rich and varied Invertebrate fauna, but the remains of Saurians and Fishes are very rare.“The Reptilia that have been found include Megalosaurus and Steneosaurus, and the Fishes are represented by Hybodus, Strophodus, etc.”
IV.—Studies in Edrioasteroidea. IV. The Edrioasters of the Trenton Limestone
Authors: Bather F. A. 
Published: May 2009

The Cover-plates of the radial grooves are preserved here and there in specimen, notably over the oral centre (Pl. X, Figs. 1, 2, 5, 7, 8), but in B they are preserved over the whole of the grooves and the mouth, though pressed down on to the floor of the grooves and into the peristome (Pl. XI, Fig. 1). Cover-plates are also present in the British Museum specimens, and are almost complete in E 16054.Each cover-plate corresponds in position with a floor-plate; so that, like the floor-plates, the cover-plates form a double series of alternating plates meeting in a zigzag median suture. The almost straight or slightly rounded outer margin of each cover-plate fits into a bevelled facet just within the rounded edge of the radial groove where the floor-plate begins its downward slope (Pl. X, Figs. 5, 7). This feature is well shown in specimen B, and there the floor-plate also shows, on each, side of the facet, and distinct from the peripodium, a slight depression, possibly for the insertion of a muscle or ligament, or possibly for the reception of the accessory cover-plate shortly to be described.
IV.—Notes on the Petrography of Egypt
Authors: Hume W. F. 
Published: May 2009

1. The ancient core of the North-East African Continent consists of the Cataract and Sudan banded gneisses, which may represent a very ancient igneous magma. They are usually much veined by granitic dykes.2. In certain places in the Arabian Desert, Cataracts, etc., these underlie highly metamorphosed schists (the mica-schists of Sikait, the calcareous schists of Um Garaiart and Haimar and of the Amara Cataracts, also the dolomites of the latter region) which are sharply separated from the banded gneisses and are possibly the oldest sedimentary representatives in Egypt.3. The greater part of the mountainous regions of the Eastern Desert and Sinai are occupied by two types of rocks, a schistose constituent overlying or being surrounded by the acid member. (a) The first-named, the Dokhan volcanic rocks and schists, are partly volcanic in origin and partly sedimentary, the former being represented by lavas of various types, while the latter are clearly altered sedimentary strata (grits, conglomerates, etc.). No fossils have yet been found, but they have their nearest lithological analogues in the latest pre-Cambrian and Cambrian series. Here are included some of the most interesting rocks of Egypt, such as the Imperial Porphyry and the Breccia Verde Antico. (b) The igneous member intruded into these ancient sediments, etc., includes a great diversity of igneous rocks, varying from highly basic to acid types.Contact-phenomena of complex nature occur at the junctions of (a) and (b).4. Red granite and dyke rocks, whose parallelism and extent of distribution present one of the most conspicuous features of the Eastern Desert of Egypt, mark the final eruptive action before Carboniferous times.5. Three periods of volcanic activity have been subsequently noted—(a) In Western Sinai in late Carboniferous times.(b) An undated series of eruptions interbedded with the base of the Nubian Sandstone or intrusive into it with marked contact alterations.(c) The basic intrusions near Cairo and the Fayum, etc., which are intimately associated with the Oligocena Continental Period in Egypt.