bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Karroo System in Northern Rhodesia, and its Relation to the General Geology
Authors: Molyneux Arthur John Charles 
Published: October 2009

In 1903 (in vol. lix of this Journal) I described the occurrence in Southern Rhodesia of deposits of Permo-Carboniferous age that have since been correlated with the Karroo System of South Africa. In the present communication will be traced their extension into Northern Rhodesia. There they are found occupying the lowlands of the Zambesi basin, and they also constitute the floors of the trench-like valleys of the Lusenfwa River (or Luano plains), of the Lukasashi River, and probably of the Luangwa. These depressions form a more or less continuous succession of troughs bisecting Rhodesia diagonally, along a distance of some 800 miles, that is, from the Deka River to the head of the Luangwa. They lie some 2000 feet below the surrounding country, which is of plateau type and is made up of metamorphic and crystalline rocks of the pre-Karroo complex. The change from upland to valleyplains is generally abrupt, giving rise to steep escarpments that appear as mountains when viewed from the lower position.
Nowhere, so far, in the vicinity of these depressions have ‘highlevel’ areas of Karroo rocks been met with on the plateau, and one's first impression is that these basins are vestiges or' an original landscape, in which the sediments were deposited. But we have been prepared by :Mr. G. W. Lamplugh, in his description of the Deka Fault, for great displacements of Karroo strata and earthmovements, and there is ample evidence to show that these valleys and low-lying regions of sediments are largely due to
The Cauldron-Subsidence of Glen Coe, and the Associated Igneous Phenomena
Authors: Clough Charles Thomas , Maufe Herbert Brantwood , Bailey Edward Battersby 
Published: October 2009

During Lower Old Red Sandstone times the district of Glen Coe furnished an arena wherein terrestrial disturbance and igneous activity combined to produce effects of imposing magnitude and, as we believe, of some theoretical importance. The paper now presented embodies an account of a cauldron-subsidence which affected an area roughly oval in shape, and measuring not less than 5 miles from side to side. We show that the subsidence took place in at least two stages, and that it was accompanied in a complementary fashion by the uprise of a series of marginal intrusions.
In the first instance the nature of the volcanic succession in Glen Coe will be dealt with, its variations from point to point will be described, and evidence will be adduced to illustrate the marked inequalities of the floor of Highland Schists upon which these volcanic rocks accumulated. The second portion of the paper is devoted to the evidences of the cauldron-subsidence, and treats in some detail of its tectonic features and the accompanying plutonic intrusions. In a final section we have added a theoretical discussion of our results.
Problems of Ore-Deposition in the Lead and Zinc Veins of Great Britain
Authors: Finlayson Alexander Moncrieff 
Published: October 2009

I. I
ntroduction
.

T
he
lead and zinc districts of Great Britain afford good opportunities for the study of these ores, owing to the variety of types met with and the advanced state of mining. Unfortunately, however, many interesting districts have been exhausted and abandoned, with the inevitable loss of much valuable information, which was not secured when the mines were in operation. As Franz Posepny has truly remarked, ‘Mining, indeed, constantly furnishes fresh evidences in new openings, but it destroys the old at the same time; and if these are not preserved for science before it is too late, they are lost for ever.’

The Geological Survey memoirs, however, have in some cases preserved many data which could not otherwise be obtained. The present work has been carried out on the basis of personal field-work in all the chief districts, coupled with laboratory work at the Imperial College of Science and Technology, where all the analyses tabulated in this paper were made.
The lead and zinc veins of Britain are chiefly of the spathic and barytic types of Freiberg mineralogists. Calcite is the predominant gangue, while fluorspar, barytes, and quartz are also abundant. Zeolites occur locally, as at Strontian in Argyllshire, and at Glendalough (Wicklow). The galena is argentiferous to a varying degree, and rich silver-ores have been mined at Hilderston (Linlithgowshire), at Alva (Stirlingshire), and in parts of Cornwall. These veins, though small and unimportant, are of the Joachimsthal and Annaberg type. The country-rock of the veins embraces nearly all
An Earthquake Model
Authors: Evans John William 
Published: October 2009

S
ome
eighteen months ago, Mr. R. D. Oldham showed to this Society a model designed to explain the mechanism of the earth-movements at the time of the Californian earthquake of 1906 in the neighbourhood of the San Andreas Fault. Though of great value in assisting us to realize the nature of the changes which then took place, it does not give prominence to the time-element so as to indicate the succession of events that led up to the earthquake shock; and it is to illustrate this aspect of the question that I have had the model constructed which forms the subject of the present paper.

It will be convenient for me, in the first place, to describe succinctly, from my own standpoint, the stages into which the conditions that precede an earthquake may be divided.
I shall on the present occasion put on one side earthquakes which are in the nature of landslips, as well as those which are the immediate result of the explosive action of the gases in igneous magmas, although there are authors who attribute to both of these modes of origin a greater importance and a more frequent occurrence than is usually accorded to them.
The typical earthquake, then, including great earthquakes like that of 1906, is, in my belief, the ultimate result of the slow relative movement of great masses of the earth's crust extending in most cases far beyond the area immediately affected by the shock. This differential creep may be in a horizontal,
Notes on the Geology of the District around Llansawel (Carmarthenshire)
Authors: Drew Helen , Slater Ida L. 
Published: October 2009

I. I
ntroduction
.

I
n
1906 and 1907 respectively, we were the recipients of the Daniel Pidgeon Fund, and decided to undertake a piece of field-work among the Palæozoic rocks of Wales.

It was suggested to us that we should make the country north of Llandeilo the seat of our investigations, with the view of discovering, if possible, the junction between the rocks of Hartfell and those of Birkhill age. We knew that Lower Birkhill graptolites had been found at Pumpsaint, some 11 miles to the north of Llandeilo, and we therefore hoped that the intermediate country might furnish sufficient fossil evidence to give us this line of junction.
With this end in view, we first made our headquarters at Llandeilo, and studied the country north of that investigated by Mr. T. C. Cantrill and Mr. H. H. Thomas. However, we found that the same monotonous series of highly-cleaved unfossiliferous (?) shales, apparently of Upper Hartfell age, continued so persistently to the north as to give us no hope of a graptolitic succession there. While pursuing our way still farther north, in search of some change in the lithology, our attention was attracted by some large slabs of a hard blue mudstone, standing outside a smithy; on close inspection these showed unmistakable fragments of graptolites, preserved in by rite. By the help of very vague directions, given in Welsh by the smith, we succeeded, after considerable difficulty, in locating the quarry from which the slabs had been brought. It is situated on
On a Collection of Insect-Remains from the South Wales Coalfield
Authors: Bolton Herbert 
Published: October 2009

I. I
ntroduction
.

I
am
indebted to the courtesy of the Director of H.M. Geological Survey, for the opportunity of examining and describing an interesting suite of blattoid remains obtained by the officers of that Survey from the South Wales Coalfield.

Insect-remains of Carboniferous age are so rare in this country that the finding of no less than nine specimens, three of them with their counterparts, constitutes an event of considerable palæontological interest. The South Wales Coalfield has thus yielded more examples and more species than all other British coalfields together. All the specimens, with one exception, are blattoid in character.
The total number of fossil cockroaches known from the Carboniferous is now great, and nearly all the numerous genera and species are founded upon the anterior wings or tegmina alone. Only once in this country, so far as I am aware, have larval stages been recognized.
The number of specimens and of species recorded from the British Coal Measures is singularly small, the great bulk of known forms occurring in Continental and North American coalfields. Dr. Henry Woodward, in quoting S. H. Scudder's census of blattoid forms, mentions 14 genera and 69 species as recorded from all Carboniferous sources.
He also mentions that Miall & Denny quote Scudder as recording the number of Palæoblattariæ at 70 species. Scudder was followed by Dr. E. H. Sellards, who took a broad survey of the whole subject, describing the structure of Palæozoic cockroaches with remarkable detail, and adding eight new species and one
The Skomer Volcanic Series (Pembrokeshire)
Authors: Thomas Herbert Henry 
Published: October 2009

I. I
ntroduction
.

T
he
region in which this volcanic series is developed occupies an extensive area in the extreme west of Pembrokeshire on the southern side of St. Bride's Bay, and includes the islands of Midland, Skomer, Grassholm, and the Smalls.

Skomer is by far the largest of the islands, and is situated about two-thirds of a mile from that part of the mainland which is known as Wooltack. It has a length, from east to west, of about 2 miles, a breadth of a little over a mile, and an area of 722 acres. Between it and the mainland lies the small island of Midland, with an area of 21½ acres, which is separated from Skomer by the Little Sound, only about 100 yards in width, and from the mainland by the broader stretch of water known as Jack Sound.
Grassholm Island lies 8 miles to the west of Skomer and covers an area slightly less than that of Midland, while the Smalls, which occupy only three-quarters of an acre, lie 8 miles to the west of Grassholm.
Skomer Island is a detached portion of that plateau which is so well marked in the west of Pembrokeshire: it rises more or less abruptly to an elevation of 200 feet; but, on account of the smaller size of Grassholm, the highest levels attained by this island fall some way short of the usual plateau-horizon, while the Smalls rise only a few feet above the level of high-water at spring-tides. All these
The Zonal Classification of the Salopian Rocks of Cautley and Ravenstonedale
Authors: Watney G.R. , Welch E. G. 
Published: October 2009

I. I
ntroduction and
L
iterature
.

W
e
were induced by Dr. Marr to undertake the examination of the Salopian rocks of the area under consideration. He had failed in former years to obtain any zonal succession of the rocks of Wenlock age in the Lake District, owing to the cleaved nature of the rocks of that age above the lowest beds containing
Cyrtograptus murchisoni
. An examination of the less cleaved representatives of the Wenlock Beds near Cautley had convinced him that a succession might be established there, similar to that described in Scania by Tullberg, and in Wales and the Welsh borderland by Mrs. Shakespear and Miss Elles.

Our study of the Wenlock and Ludlow rocks of the Cautley and Ravenstonedale area has convinced us that these beds are capable, of a division into zones, although some of the zones recognized farther south apparently do not persist when traced northwards to this district.
The Cautley and Ravenstonedale area is situated north of Sedbergh; its northern and eastern limits are defined by Carboniferous rocks, but on the west it is continuous with the Salopian of the Lake District.
The physiography of the district and the features due to ice-action have recently been described by Dr. Marr & Mr. Fearnsides: it will suffice, therefore, to mention here that the area is a very hilly one, the fells often rising steeply from the 600- to the 1750-foot contour-line. North-west of the Rawthey the hilltops are everywhere formed of hard grits of Ludlow age, while on
Some Observations on the Eastern Desert of Egypt; with Considerations bearing upon, the Origin of the British Trias
Authors: Wade Arthur 
Published: October 2009

I. Introduction.

D
uring
the past two years I have on several occasions visited that part of the Eastern Desert of Egypt which borders the Red Sea near its junction with the Gulf of Suez. While there I made observations of desert conditions and phenomena which appeared to me to be of interest to the student of the conditions determining the origin of the Triassic rocks of Britain.

A few years ago the late J. Lomas dealt very fully with these conditions, having made some studies of South African and Egyptian deserts, and it is with pleasure that I find myself able to confirm or to supplement several of the conclusions to which he came.
II. The Igneous ‘Gravels’ and Pebble-Beds.
The western side of the Red Sea is flanked by a wall of hills running generally in lines parallel with the general trend of the coast. They rise abruptly from a level or gently sloping coast-plain, which varies in width from under 1 to over 10 miles. The hills are composed chiefly of igneous rocks: red and grey granites, dark andesites and purple porphyries, with some tracts of gneiss and schist.
At the foot of the hills, large mounds of angular débris of the igneous rocks occur, running in tongues from the hills out on to the plain, or forming low foot-hills which run parallel with the main range.
The mounds themselves consist of unsorted angular blocks and flakes varying greatly in size, and showing as a rule no signs
Trilobites from the
Paradoxides
Beds of Comley Shropshire
Authors: Cobbold Edgar Sterling 
Published: October 2009

Introductory remarks
In a previous communication I called attention to certain trilobites associated with Callavia. callavei Lapw., from the limestones at the top of the Lower Comley Sandstone, and indicated the correspondence of many of the forms with those of Dr. Matthew's Protolenus Fauna from the Cambrian of the Atlantic province of North America.
The object of the present paper is to describe and figure the trilobites of the Upper Comley Sandstone, and to endeavour to estimate the faunal importance of the physical break between the upper and the lower groups of strata.
Many of the specimens have been obtained during the progress of the excavations that I have been conducting for the British Association; others have been collected at various times during the past twenty years; and, through tho kindness of Prof. Charles Lapworth, I have had access to the type-specimens of his Paradoxicles groomii, which are now figured for the first time.
The fossils described in this paper occur at three distinct horizons. A lower one, the Quarry-Ridge Grits, at the base of the Paradoxides-bearing beds of the Comley Sandstone, where they rest unconformably upon the Protolenus and Callavia Beds; a second, the Hill-House Beds, some 300 feet higher in the succession; and a third, the Shoot-Rough-Road Beds, near the top of the Comley Sandstone Group, presumably several hundreds of feet higher.
The stratigraphical relations of these beds to one another and to the strata above and below them, the local names adopted, and the horizons from which
Kainozoic Mollusca from Cyrenaica
Authors: Newton Richard Bullen 
Published: October 2009

I. I
ntroduction
.

A
mong
the geological specimens obtained from Cyrenaica by Prof. J. W. Gregory, during a journey through that province of Northern Africa in the summer of 1908, are a considerable number of molluscan remains, which it has been my privilege to study and report upon in the following notes. It may be at once mentioned that the more important part of this collection will be presented by Prof. Gregory to the Geological Department of the British Museum (Natural History).

Speaking generally, the shells are badly preserved, and some consist merely of internal casts; hence only one new species has been made, namely,
Æquipecten cyrenaicus
, referred to the Priabonian horizon—a more useful purpose, it is hoped, being served in the endeavour to show relationships to already described forms.

The specimens are, however, easily divisible into various groups of the Kainozoic System, none offering characters that would indicate their attribution to the Mesozoic or any older series of the sedimentary rocks.
The more ancient specimens are the most numerous and probably of greatest importance, since they denote such horizons as the Lutetian, Priabonian, Aquitanian, and Vindobonian: those of later age belonging both to the earlier and to the newer deposits of the post-Pliocene Epoch.

The rocks associated with the Lutetian and Priabonian fossils are full of nummulites and occasional specimens of
Orthophragmina
; while those that form the matrix of the Aquitanian and Vindobonian specimens exhibit foraminiferal organisms such as
Operculina, Amphistegina, Lepidocyclina
, etc., but no nummulites. This is interesting confirmation of
On the Interglacial Gravel-Beds of the Isle of Wight and the South of England, and the Conditions of their Formation
Authors: Hull Edward 
Published: October 2009

Abstract
The Author, after referring to the investigations of previous authors, especially of Mr. Codrington and the officers of the Geological Survey, with which he in the main agrees, points out that the origin and mode of formation of the gravel-terraces of the Isle of Wight and of the New Forest district are still open to discussion. He points out that the levels of the higher beds on both sides of the Solent, up to about 400 feet, indicate the amount of subsidence of the whole area at a time when the stratified gravels, composed mainly of rolled flints, were formed at the margin of the uprising ridges of the Chalk in the post-Glacial Epoch, for this part of England. Preceding this was the great uplift indicated by Godwin-Austen, by which the British Isles were joined to the continent as land. By this uplift the English Channel was laid dry, and along its centre there ran a river from its source about the Straits of Dover to its outlet into the ocean through the Continental Platform. This river-channel is laid down on the Admiralty Charts under the name of ‘the Hurd Deep’ for a distance of 30 miles of its course, and has been named by the Author ‘the English Channel River.’
The Author considers the gravel-beds of this region to be the representatives of the High-level Gravels of the Midlands and Cromer; also of the ‘Interglacial Gravels’ of Cheshire and Lancashire; and of the shell-bearing beds of the Denbighshire Hills, and of Moel Tryfaen in Wales, at levels of about 1200 feet above the sea.
The Glacial Sections round Sudbury (Suffolk)
Authors: Hill Edwin 
Published: October 2009

The sections round Sudbury are called in the Geological Survey Memoir of 1885 ‘perhaps about the finest in any inland spot in East Anglia.’ They are described in the Survey Memoir on North-West Essex (1878); and there are further notes in that on Ipswich, Hadleigh, etc. (1885).
There is a paper by Dr. Marr in Geol. Mag. 1887 (p. 262); there have been excursions to the neighbourhood on the occasion of the Geological Society's Centenary in 1907, and by the Geologists' Association in 1898 and 1910, of which brief descriptions have been published. I know of nothing else. Since publication of the two Survey Memoirs some pits have been closed; some new ones opened; and many extended considerably. These changes have disclosed facts of considerable interest, which deserve to be put on record.
I. The Principal Pits.
I will name the position and contents of the principal pits, giving numbers to them for use in this paper and notes of references to them in the Survey Memoirs.
Beginning with those on the high road leading eastwards from the town, Green's Pit (1) has been filled in, but the singular contorted sands are still visible. On the south side of the road two pits (2) called Victoria on the Ordnance Map and in the Geological Survey Memoirs, now joined at the top, show Chalk, Thanet Sands, Crag, gravels, and a patch of Boulder Clay. Farther out along the road, on Gallows Hill, two brickworks (3), called California on the Ordnance Map
Petrological Notes on Guernsey, Herm, Sark, and Alderney
Authors: Bonney T. G. , Hill Edwin 
Published: October 2009

During the nineteen years which have passed since we visited the Channel Islands, our friend Mr. John Parkinson has examined parts of Jersey with results described in four valuable papers contributed to this journal. He then turned his attention to Northern Guernsey, and in a short but very important summary of his work on its diorites, announced his conclusion that the syenite, horn-blende-gabbro, and diorite, which had been separated by the older observers, were not genetically distinct, but were related to each other as the products of the differentiation of a single magma. Our brief visits to the island in 1888 and 1891 had shown us that the above-named distinctions could hardly be maintained, and prepared us for some such conclusion as that just mentioned.
The principal object of our visit in September 1910 was to make a further examination of this question and to study some of the numerous dykes a little more fully than Mr. Hill had been able to do when drawing up his sketch-map and general account of the geology of Guernsey.
We also spent two full days in Alderney, an afternoon in Herm (both unknown to one of us), and twice visited Sark, in order to re-examine some specially interesting sections.
I. The Gneiss.
The gneiss, which occupies the larger half of Guernsey, forming the grand crags and beautiful bays of its more southern shores, was described by Mr. Hill in his paper on this island, to which Prof. Bonney contributed some petrographical notes.
At
The Ordovician and Silurian Rocks of the Kilbride Peninsula (Mayo)
Authors: Gardiner Charles Irving , Reynolds Sidney Hugh 
Published: October 2009

I. Introduction.
The Kilbride area with which this paper deals lies some 5 miles to the south of the Glensaul area described by us in 1910. Its limits are very sharply defined. It forms a peninsula bounded by two long inlets from the south-western corner of Lough Mask, the northern one being known as Derry Bay or Derrypark Bay, the southern as Kilbride Bay. It has a length from east to west of about 4½ miles, and a breadth of about a mile and a half. It ends to the west in the alluvial tract through which the Finny River runs. From this low ground the land rises rapidly to a ridge which attains its highest point at Knock Kilbride (1230 feet). Farther east is another eminence (Knocknamuck), and then the ground sinks slowly through Fox Hill to the shore of Lough Mask. The descent from the high ground to Derry Bay on the north is far steeper than that to Kilbride Bay on the south, a fact intimately associated with the geological structure of the country.
Little has been written about the geology of this area. Some description of it is given in the Memoirs of the Geological Survey. The igneous rocks are referred to as being everywhere felsite; the presence of ash is mentioned; and allusion is made to the finding of Llandovery fossils at several points on the southern side of the peninsula.
In the ‘Annual Report of the Geological Survey for 1896’ (pp. 49–51) a general