bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Chellaston Gypsum Breccia in its Relation to the Gypsum-Anhydrite Deposits of Britain
Authors: Smith Bernard 
Published: October 2009

I. Introduction.
It is now generally accepted that the extensive beds of gypsum that occur in this country are the deposits of salt lakes or inland seas, and the opinion has been steadily growing that the sediments with which they are usually associated are the products of weathering of an arid region.
In recent years the geographical conditions of the periods when gypsum was deposited have been discussed by numerous writers, including Beasley, Bosworth, Burns, Geikie, Goodchild, Hewitt, Jukes-Browne, Lomas, Metcalfe, Wade, and Watts. The object of this communication is not so much to discuss the geography of these periods, as to throw some light upon the actual mode of accumulation of gypsum, chiefly from the standpoint of the field-observer.
In any question dealing with gypsum, however, it is almost impossible to avoid dealing also with the anhydrous form of calcium sulphate, since the two minerals occur so frequently in intricate and puzzling association. The main point at issue is whether gypsum is to be regarded as an original deposit, or as a secondary formation.
We may dismiss the isolated occurrences of gypsum which result from the decomposition of sulphides in rocks containing lime, as being a minor point well understood, and confine ourselves to the more extensice deposits occurring as beds and smaller masses, or as a matrix to the rocks in which the thicker deposits are found.
Various suggestions have been advanced to explain the origin of these deposits:—
(i) Some may be due to evaporation by concentration
The Geology of the Marble Delta (Natal)
Authors: du Toit Alexander Logie 
Published: October 2009

The crystalline dolomitic marbles near Port Shepstone have formed the subject of no less than three communications to this Society.
That by C. L. Griesbach, written nearly half a century ago, gives us the first glimpses of this interesting occurrence; the next, by David Draper was fuller, but lacking in most of the important details; the third, by Dr. F. H. Hatch & Mr. R. H. Rastall is a particularly valuable contribution, especially from the petrographical standpoint: the intrusive relationship of the granite is placed beyond dispute, and the operation of the action known as dedolomitization is fully demonstrated.
Consequently, it is not inappropriate that the principal conclusions arising out of the geological survey of the area (carried out in 1915–16) should be communicated through the same channel, especially as they confirm and amplify the expressions of Hatch & Rastall as to the nature of the metamorphic actions involved.
The sole point of disagreement concerns the ‘boulder’ of alkali-granite, which, from the evidence available, can only have formed part of an intrusive tongue in the marble, while the other reputed instances of ‘inclusions’ must be placed in the same category.
The object of the present paper is the description of this and certain other cases, where there has been an actual transfer of material from the intrusion across the contact to the rock invaded, a rather infrequent phenomenon, and one termed ‘contact-metasomatism’ by J. Barrell, and ‘pneumatolytic contact-metamorphism’ by Y. M. Groldschmidt; the action termed ‘calcitization’ is also described and
The Pleistocene Deposits around Cambridge
Authors: Marr John Edward 
Published: October 2009

Since the year 1910 I have devoted considerable attention to the Pleistocene Deposits of the Cambridge district, and believe that my observations will be useful as an aid to future students of these accumulations.
In a paper read before the Cambridge Philosophical Society in 1917, I gave a brief account of the conclusions which I had reached, and noted the importance of a study of the Pleistocene deposits of the Great Ouse Basin,
‘for in this area we get evidence of the relationship of the Palæolithic deposits to those which were formed during a period of submergence and re-emergence, and also to accumulations which give evidence of the occurrence of more than one cold period.’
In the present paper I propose to confine myself to a consideration of the deposits in the immediate neighbourhood of Cambridge, with special reference to the sequence of the various members of the Pleistocene accumulations as there displayed (see fig. 1, p. 205).
In the previous literature devoted to this subject undue stress has been laid upon relative elevation above present river-level. Of recent years it has been recognized that, owing to alternate erosion and aggradation, difference of level must be treated cautiously, for reasons which I gave in the paper to which I have referred. The researches of palæontologists have enabled us to construct a timescale based upon fossil evidence (including that furnished by human implements), and I have relied largely upon this evidence in attempting to determine the time-sequence of our local deposits.
Geological Sections through the Andes of Peru and Bolivia: II—From the Port of Mollendo to the Inambari River
Authors: Douglas James Archibald 
Published: October 2009

I. Introduction.
In a former communication to this Society, published in April 1914, I described a geological section through the South American Andes, from Arica on the Pacific coast of Northern Chile to the Bolivian Yungas.
The present paper, the publication of which has been long delayed owing to the War, is a further contribution to the same series, the result of work undertaken on the Baiston Expedition to Peru. It deals with a second and parallel section drawn through the south of Peru from the port of Mollendo to the River Inambari, a tributary of the Madre de Dios, one of the head-waters of the Amazon. That part of the country illustrated in the western half of the section, which includes the important town of Arequipa and the port of Puno on Lake Titicaca, is accessible by the Southern Railway of Peru, of which we were enabled to make full use during the course of our work from Arequipa to the coast, through the kindness of Mr. McCulloch, manager for the Peruvian Corporation. I have also to thank Mr. F. A. Corry, chief engineer of the line, for the original from which the sketch-map (fig. 1) was taken.
For the continuation of the section beyond Puno through the Eastern Cordillera, it was found necessary to proceed northwards as far as Tirapata, a station on the Puno-Cuzco railway, whence access could be gained, by the trail of the Inambari Rubber Company, to the forested region of the Montana.
The railway
A Comparative Review of Pliocene Floras, based on the Study of Fossil Seeds
Authors: Reid Eleanor Mary 
Published: October 2009

I. Introductory.
The work on which the following paper is based has been rendered possible only by the help received from many botanists. If it were not for a considerable private collection of seeds and fruits, mounted for microscopic examination, it would have been impracticable, either to gain the knowledge requisite for carrying out, the work, or to make the preliminary determinations, which are necessary before it is possible to use the great collections of our public herbaria.
The formation of this collection of seeds, though initially, and essentially, due to my late husband's careful and unwearying labour, has for some years passed the bounds when the work of any single collector could meet the demands of the study of fossil seeds. Help has, however, been received from all sides: by gifts of specimens from Kew (both the Gardens and the Herbarium), the British Museum, the Herbarium of the Muséum d'Histoire Naturelle, Paris, and the Gardens of La Mortola; also by contributions from botanical friends, among whom I would especially mention Mr. James Groves, Mr. C. E. Salmon, Mr. T. A. Dymes, M. Émile Gadeceau, M. J. Simon, and Dr. Tokotaru Ito.
As well as for contributions to my collection, I would also thank the officers of Kew and the British Museum, for their unfailing kindness in helping while I have been at work in the respective Herbaria, and in lending specimens for photography and study.
Of late my work has been greatly furthered, particularly the photographic part of it,
A Natural ‘Eolith’ Factory beneath the Thanet Sand
Authors: Warren Samuel Hazzledine 
Published: October 2009

Experiment has shown that the mechanical movement of one flint grinding against another under pressure will produce edge-chipping similar in every respect to that which is seen upon the Eoliths.

Direct evidences that such processes have actually been in operation in Nature have been brought forward by M. I'Abbé H. Breuil
1
and Mr. F. N. Haward,
2
as also by the present writer
3
; but more comprehensive knowledge of the work of Nature is urgently needed.

One must never forget that static energy in equilibrium is ineffective: there must be some disturbance of equilibrium for any chipping force to be set in action. That is to say, there must be at least vibration, but the greater the differential movements, and as a consequence the more the stones grind over each other, the more favourable the conditions become for the production of edge-chipping.
Certain types of superficial drift fulfil these conditions, through the, prolonged operations of soil-creep, better than they can be fulfilled in more deeply seated situations. But the Eoliths that are found in them, which some investigators believe to be results of these mechanical movements, can always be claimed by others as human implements.
The conditions at the base of the Tertiary System do not always fulfil what is needed. The section at Harefield can be taken as a good illustration: here is evidence of immense pressure, without any appreciable amount of differential movement. In consequence we find that the fractures are promiscuous, and strike through the heart of
On the Junction of Gault and Lower Greensand near Leighton Buzzard (Bedfordshire)
Authors: Lamplugh George William 
Published: October 2009

I. Introduction.
Eighteen years ago the late J. F. Walker and myself described to the Society a remarkable fossiliferous limestone occurring immediately beneath the Gault at Shenley Hill near Leighton Buzzard. The bed differed, both in its lithological characters and in its fossil contents, from any other deposit then known at this horizon in England, and the problems which it presented demanded, and have received, further investigation. Walker continued assiduously to explore the palaeontology of the bed, until his work was cut short suddenly by death in 1907. Partly by personal visits to the locality, but mainly through the agency of the quarrymen, he had been able by this time very largely to increase his collection of the fossils, and had made progress in his study of the brachiopodfauna, which was his particular interest. It was his intention ultimately to deal exhaustively with this element of the fauna, and, as a preliminary step, he had already prepared and sorted many thousands of specimens into their proper specific relationship, with provisional determinations where possible. The collections thus arranged by his own hand are, however, all that remains to us of the work that he did after the publication of our joint paper. Some information culled from them will be given in a later part of the present paper.
While my late colleague continued to explore the palaeontology of the Shenley bed, I devoted attention, as before, more particularly to its stratigraphical aspect. Visits in successive years constantly revealed new features of
The Structure of the South-West Highlands of Scotland
Authors: Bailey Edward Battersby 
Published: October 2009

I. Introduction.

The gradual development of structural interpretation in regard to the South-West Highlands of Scotland has much in common with the long-continued building of some great cathedral. The workers have been many, each with his own individuality, and each influenced by the spirit of his time. In these circumstances, preparatory demolition has been an almost inevitable feature of every attempt at improvement. But one is emboldened to the task by the thought that restoration can be carried out if occasion proves its need: a fairly representative literature enshrines the observations and opinions of the long line of researchers.
1

Statement of the Problem.

As a preliminary to discussion, the following dogmatic statement is offered. The schists of the South-West Highlands of Scotland belong to three main structural divisions, which, in descending order, are (fig. 1, p. 84 & Pl. 1):—

Loch-Awe Nappe,

Iltay Nappe,

Ballappel Foundation.

The first title is derived from Loch Awe. The second is a hybrid of Islay and Loch Tay. The third is compounded from Ballachulish, Appin, and Loch Eilde.
Each great division has its particular stratigraphical facies, although there are certain correspondences which suggest stratigraphical correlations from one to another.
The Loch-Awe Nappe is relatively simple in structure. The Iltay Nappe includes two important recumbent folds—the Ben-Lui Fold, a syncline closing towards the north-west, and the Carrick-Castle Fold, an anticline closing towards the south-east (fig. 4, p. 102 & Pl. 1). The Ballappel Foundation is a structural complex, with the Ballachulish and Appin Nappes among
The Bala Country: its Structure and Rock-Succession
Authors: Elles Gertrude Lilian 
Published: October 2009

I. Introduction.
The district dealt with in the present paper lies all round Bala Lake, though attention has been paid more particularly to the ground lying south-east and east of the lake, as affording an opportunity for the study of problems of special interest regarding the succession and structure of the area.
The whole district has been classic ground since the days of Sedgwick, and its difficulties were vividly described later by Jukes; it is just these difficulties that make the area so intensely interesting, and, largely owing to the more detailed mapping that can be carried out in these days, it is now possible to suggest a solution of some, at any rate, of the problems—more particularly those of a stratigraphical and structural nature. The palæontological problems are somewhat different, and will not be dealt with in detail at present.
Previous Work.
By far the most important contributions made to our general knowledge of the district are those of Sedgwick, Jukes, and Ruddy, though Ramsay and, in later times, Lake have dealt with the question of the faulting as connected with the development of the valley in which the lake lies.

Sedgwick made two important contributions to the study of the area. In the earlier paper on the ‘Calcareous Slates & Limestones of Glyn Dyffws on the Holy head Road, west of Corwen, & of Rhiwlas north-east of Bala,’
1
he gave what he believed to be the succession in the area, and illustrated it by sections made as early
A Composite Sill at Newton Abbot (Devon)
Authors: Shannon William George St. John 
Published: October 2009

I. Introduction.
The sill which is described in this paper forms the summit and part of the northern flank of Knowles Hill, Newton Abbot, 6-inch Ordnance-Survey Map 109, S.E. The hill is bounded on all sides except the western by the alluvium of the Teign and its tributary the Lemon; it forms a prominent hog-back lying in the fork between the two rivers. The base of the hill is formed of Upper Devonian slates, and these are continuous to the west, where, at a distance of about half a mile, another outcrop of dolerite occurs at High week Church. The occurrence of picrite was discovered by Busz, and a short description of the sill and of the presence of original quartz is given in the Geological Survey Memoir on the ‘Geology of Newton Abbot,’ No. 339, 1913.
II. Field Relations.
The summit of Knowles Hill has been quarried, and a smaller quarry exists by the footpath on the north of the hill, bordering the Teign alluvium. The rocks described are mainly from the upper quarry. The northern slopes of the hill are in pasture, and the exposures are too weathered to admit of a petrographic description of the rocks; on the east, the geological lines have been drawn from very limited exposures, as the area has been completely built over. The sill is intrusive into Upper Devonian slates; its lower boundary is indicated by the fact that the floor of the quarry is in slates, the whole of the sill
Notes on the Phosphate-Deposit of Ocean Island; with Remarks on the Phosphates of the Equatorial Belt of the Pacific Ocean
Authors: Owen Launcelot 
Published: October 2009

I. Introduction
Within the tropical belt of the Pacific Ocean occur several islands containing deposits rich in calcium phosphate. The majority of these islands are situated within 10° of the Equator, and between longitudes 140° E. and 180° E.
At the present day, the islands the deposits of which may be considered as of commercial importance are Angaur, Makatea (near Tahiti), Nauru, and Ocean Island. Other islands, most of which have been worked in the early days of the phosphate industry, are Baker, Howland, Phoenix, Sydney, Maiden, Christmas, Flint, Starbuck, Browse, Lacépeède, Laysan, Cornwallis, and Clipperton.
Although from time to time various theories have been put forward as to the origin of these phosphate deposits, there can be no reasonable doubt that they are all due, primarily, to bird-droppings.

With the one exception of Clipperton Island, the deposits consist entirely of more or less leached guano overlying a coral-floor which is, to a greater or less extent, changed by metasomatism into tricalcium phosphate. The deposits mentioned as being of commercial importance have been leached so completely that the soluble phosphates have entirely disappeared, some of the phosphate on Ocean Island, for example, containing over 90 per cent. of tricalcium phosphate (Ca
3
P
2
O
8
). On Malden Island, where the birds still congregate, all three forms of calcium phosphate (CaH
4
P
2
O
8
, CaHPO
4
, and Ca
3
P
2
O
8
) are found; while on Clipperton Island a mass of trachyte, about 60 feet high, rises through the coral in the south-eastern part of the island. The original structure of the trachyte
The Igneous and Associated Rocks of Llanwrtyd (Brecon)
Authors: Stamp Laurence Dudley , Wooldridge Sidney William 
Published: October 2009

(1) Introduction
North of the little town of Llanwrtyd Wells lies an oval patch of igneous rocks, about 3 miles long and half a mile broad. It has long been known that these rocks occupy the core of an anticline—that of the Vale of Towy—which strikes approximately north-north-east and south-south-west. Some years ago I visited the igneous rocks in the neighbourhood of Builth (described by Mr. Henry Woods in 1894). It has usually been presumed that the igneous rocks of Llanwrtyd, which locality is about 10 miles west-south-west of Builth, are of the same age as those near the latter town. Accordingly, in order to test the truth of this belief, a survey of the Llanwrtyd rocks was begun. It was found that the igneous rocks differed considerably from those near Builth, but at that time no palsæontological evidence of their age was found. In 1920, while studying the Siluro-Devonian junction in Central Wales, I took the opportunity of revisiting Llanwrtyd Wells for the purpose of completing the mapping of the igneous rocks and Ordovician sediments. I was accompanied on this occasion by Mr. Wooldridge, who has undertaken the petrological description of the rocks.
(2) Previous work
The literature relating to this district is scanty. The only description is that given by Sir Roderick Murchison. He states that the presence of mineral springs at Llanwrtyd Wells led him to suspect the presence of igneous rocks in the neighbourhood, and his investigations proved that such rocks did occur. His account occupies
Oligocene Mosquitoes in the British Museum; with a Summary of our present Knowledge concerning Fossil Culicidæ
Authors: Edwards Frederick Wallace 
Published: October 2009

In 1916 Prof. T. D. A. Cockerell described some fossil mosquitoes in the United States National Museum, from the Oligocene of the Isle of Wight. The material that he described consisted only of duplicates from the Brodie Collection, the main portion of which remained in the Geological Department of the British Museum (Natural History). When Prof. Cockerell came to England in 1920, he undertook the study of the main Brodie Collection of fossil insects, and found in it a considerable number of mosquitoes; at his suggestion I readily undertook to work out this material, and I wish to express my indebtedness to him for assistance and advice. My thanks are also due to Dr. A. Smith Woodward, F.E.S. and to Dr. F. A. Bather, F.E.S., for the facilities which they have afforded me. The descriptions and figures of Cockerell not being entirely clear, Dr. Bather obtained from Dr. R. S. Bassler, of Washington, photographs of the types of CockerelFs three species. These are reproduced here (PI. VII), and have been of great assistance in deciding upon the synonymy.
As explained by Prof. Cockerell in a recent paper, the material examined belongs in part to the British Museum and in part to the late Mr. R. W. Hooley, F.G-.S. In the descriptions which follow, specimens belonging to the Museum are referred to by the letter I and their register-number, those belonging to Mr. Hooley (but deposited at the Museum) by the letter H. All the material is from G-urnet Bay (Isle
The Geological Structure of the Clevedon-Portishead Area, Somerset
Authors: Reynolds Sidney Hugh , Greenly Edward 
Published: October 2009

The area described in the following paper is, in the main, a prominent ridge some 4 miles long, forming the extreme north-western portion of Somerset and stretching from Portishead in the northeast to Clevedon in the south-west (Pl. XXXIX, fig. 1). It is separated from the Clifton—Clevedon ridge by the Gordano valley; but, as one proceeds south-westwards, the two ridges are seen to approach and eventually come together at Clevedon.
The main part of the ridge is geologically very simple, consisting of Old Red Sandstone overlain by the Carboniferous Limestone Series dipping south-eastwards; but at each end the structure becomes very complicated and difficult of interpretation. Owing to this fact, it has been thought desirable to describe the main part of the ridge first.
The district was mapped by Sanders on the scale of 4 inches to the mile, and the Geological Survey for the 1-inch map made but slight alteration in his lines. Little has been written, except about the Portishead end of the ridge. This, however, was described in considerable detail by Prof. C. Lloyd Morgan, and, as his paper deals fully with the earlier work, it will not be necessary to repeat the references to this subject. Arthur Yaughan's work on the palæontological sequence in the Carboniferous Limestone of the Bristol area led him to determine the horizon of the rocks at the chief exposures throughout the district, but he did not attempt any general explanation of the geological structure. Some account of the chief exposures will