bluuebunny/crossref_metadata_2025 huggingface dataset:
Two Genera of Carboniferous Echinoidea (
Lepidocidaris
and
Hyattechinus
) new to Britain
Authors: Hawkins Herbert Leader
Published: October 2009

Introduction

The remains of echinoids occur at almost every horizon of crinoidal limestone in the Lower Carboniferous rocks of Britain; but they consist usually of isolated plates and radioles.
Archæocidaris, Palœechinus, Perischodomus
, and
Lovenechinus
must have thrived in our Carboniferous seas, and
Melonechinus
was by no means rare. But the conditions of deposition of the limestones, together with the collapsible nature of the tests, almost always resulted in disintegration and scattering of the remains. Only in the shaly facies of the Lower Carboniferous was the water sufficiently still, and sedimentation adequately rapid, to leave the component parts of echinoid tests in their natural association. Such conditions occurred in the Fifeshire area, where Mr. J. Wright has found fairly complete examples of the excessively fragile
Lepidesthes
together with great quantities of almost perfect crinoids. They also prevailed in the Bolland district of Lancashire, where Clitheroe has long been famed for its yield of crinoids, blastoids, and echinoids. A similar shaly development characterizes the “Lower Limestone Shales” and immediately succeeding strata at the base of the Carboniferous Limestone in South Wales. In this paper I am able to record an extraordinary find of echinoid tests at that horizon in Pembrokeshire. Perhaps the “Marbre noir de Dinant” may be cited as a neighbouring illustration of an argillaceous Carboniferous Limestone noteworthy for the wealth and preservation of its echinoid fauna.

The abundance of echinoid fragments in the purer and more massive limestones shows that the sea-urchins lived quite as1 freely in the open water
The Eocene and Pliocene Deposits of Lane End, Buckinghamshire
Authors: Wooldridge Sidney William , Ewing Colin James Craig
Published: October 2009

An account of the geology of the Lane End district was published in 1925 (Wooldridge & Gill), following special excavations undertaken by a Committee of the British Association for the Advancement of Science with the object principally of confirming H. J. Osborne White's earlier account of quartzose gravelly elements in the Reading Beds. The pit described by him was reopened in part, and further exposures of the gravelly beds were examined, notably in a pit on Bolterend Common. The conclusion reached was that the London Clay was normally superimposed on the beds in question, and that their Eocene age was thereby definitely established. This interpretation carried with it two important corollaries: namely, (a) that the Chalk cover, north-west of the London Basin, must have been locally breached in early Eocene times, permitting the contribution of Lower Cretaceous and Jurassic material to the Eocene sediments; and (b) that a distinctive polygenetic marginal facies of the Reading Beds formerly existed, of which the Lane End Reading Beds were a surviving remnant.

Recently, much new geological information has become available in this district. New pits have been opened and certain of the older exposures have been extended. Moreover, a water reservoir has been constructed on the hill-top in Widdenton Park Wood and a water-tower erected on the companion hill-top of Fining Wood. In connexion with them, an extensive series of deep pipe-line trenches was dug; these were kept under continuous observation by one or other of the present authors and the information obtained
Geological Observations on the Northwest Frontiers of the Anglo-Egyptian Sudan and the adjoining part of the Southern Libyan Desert
Authors: Sandford Kenneth Stuart
Published: October 2009

In the autumn of 1932 an expedition led by Major R. A. Bagnold, Royal Corps of Signals, traversed about 6000 miles of country between the Nile, the southern boundary of Italian Libya, and the northern and eastern frontiers of French Equatorial Africa (Bagnold, 1933). The geological objects of the expedition were to map the route and to study the wedge of Sudanese territory, lying between the northeastern frontier of French Equatorial Africa and the southern part of Libya, known as the Sarra Triangle, east of which lies the massif of 'Uweinat. The border hills of Erdi and Ennedi, where in Sudanese territory, and the oases of the southern part of the Libyan Desert were also to be studied.

Scientific work was practically limited to the line of route, since so long a journey without permanent bases for water, fuel, and supplies must be executed with the utmost dispatch. The zones of operation lie hundreds of miles from the nearest administrative centres, and any severe breakdown must prove serious; moreover, care was necessary in case of encounters with the fugitives from Kufara, captured by the Italians in 1930, and with unadministered people who make raids from the border hills. Much of the country in the vicinity of these hills proved almost impracticable for motor transport. As part of the ground had not previously been visited by Europeans, the following account may serve as a preliminary survey.

The expedition owed material support to the Sudan Government, the Royal Geographical Society, and Dr.
The Superficial Deposits of The Country north of Stratford on Avon
Authors: Tomlinson Mabel Elizabeth
Published: October 2009

The district under discussion in this paper comprises:—

(a)

Areas in which the superficial deposits have been mapped and studied in detail by the author
(Pl. XXVII, map).

(i)

The valley of the Warwickshire Avon between Leamington and Stratford and of
its tributary, the Dene, together with the adjacent country extending eastwards to the longitude of
Compton Verney and Leamington, and westwards to the river Arrow.

(ii)

The country roughly bounded by the longitude of Warwick
and Kenilworth Castle (W. 1° 35′′) on the east and by the upper valley of the
Alne on the west, and extending northwards from the district described above (i) to the country
included in the Birmingham Sheet (168) of the Geological Survey 1-inch map.

(iii)

The valley of the Alne to its junction with the Arrow.

(b)

A wider area, surrounding the aforementioned districts, in which the superficial deposits have
been examined, but where continued observation has not been possible.

Reference will be made to the lower valley of the Warwickshire Avon, the superficial
deposits of which I have described elsewhere (Tomlinson, 1925), and to the valley of the Warwickshire Stour, the superficial deposits of which have been described by Mr. H. G. Dines (Richardson and others, 1929) and myself (1929).

The object of this paper is to attempt a classification of the superficial deposits of the areas which have just been defined, with a view to determining their distribution and relative age. Since the district presents so many difficulties of interpretation and appears
The Stratigraphy and Tectonics of the Cross Fell Inlier
Authors: Shotton Frederick William
Published: October 2009

I. Introduction

The Cross Fell inlier of older Palaeozoic rocks extends for 16 miles from Roman Fell to near Gamblesby, as a narrow belt of highly-disturbed country parallel to the north-north-west and south-south-east escarpment of the Westmorland and Cumberland Pennines. Its boundary on the east is formed by the outcrop of the gently dipping Carboniferous sediments which constitute the Alston Block (Trotter and Hollingworth, 1928). On the west, if we include as parts of the inlier certain blocks of greatly disturbed Carboniferous strata, the boundary is defined by the appearance of the down-faulted Permo-Triassic rocks of the Vale of Eden. These are folded into a gentle syncline, or series of synclines in echelon, devoid of complex folding and fractured by but few faults. Between these two bounding regions of quiet tectonic history, the inlier exhibits a complex maze of folds, faults, and thrusts which are not limited to the outcrops of older Palaeozoic rocks. For some distance to the north, faults and steep dips affect the Carboniferous formations east of the Pennine Fault; while south-eastward from Roman Fell the disturbances continue with undiminished intensity for seven miles or so until, east of Brough, some, at least, appear to merge into the Dent Fault system of earth movements.

It is unnecessary, at this stage, to recall more than a few of the papers which deal with the Cross Fell area. Early work by Goodchild (1874, 1889) and by Nicholson and Marr (1891) made great advances in the stratigraphy of the area.
The Ordovician Rocks of the Trefriw District (North Wales)
Authors: Davies D. A. Bryn
Published: October 2009

The area described is a rugged and mountainous tract on the eastern flanks of Snowdonia, lying largely between the villages of Dolgarrog, Trefriw, and Capel Curig. The eastern boundary is defined by the alluvial flats of the Conway valley, and the northern by the Afon Porthllwyd and Afon Eigiau. In the south and west, the mapping has been carried as far as was considered necessary for the elucidation of the geology.

The area is shown on the six-inch Ordnance Survey Map, Caernarvonshire, Sheets XVIII and XIII, with portions of the quarter-sheets XIV SW. and XIX NW., and on the one-inch Geological Survey Map, Sheet 78 SE. (Old Series). The results of the present work are embodied in the map (PI. VII) accompanying this paper.

The area was first described by Sir Andrew Ramsay (1866), who himself mapped the greater portion of the district. His colleague Aveline was responsible for the mapping of the country “east of Llyn Eigiau”. Ramsay regarded the whole succession of “slates and grits with interbedded felspathic traps, felspathic and sandy ashes” as “Caradoc or Bala” age, and recognized at the top of the volcanic series in the neighbourhood of Llyn Crafnant and Llyn Geirionydd a bed of muddy crystal tuff—“a dark blue or black slaty base containing numerous scattered phenocrysts of yellow felspar.” In this “topmost igneous bed” he found at Cwm Llanerch, 2½ miles south of Llanrwst, an abundance of
Trinucleus concentricus
, Leptæna sericea, and “other common Bala fossils”.

Ramsay considered the upper ashes of
The Aymestry Limestone of the Main Outcrop
Authors: Alexander Frances Elizabeth Somerville , Caldwell Née
Published: October 2009

I. Inroduction

The main outcrop of the Aymestry Limestone forms a sinuous ridge, doubled between Aymestry and Ludlow, about 1000 feet above O.D. It is 25 miles long and lies within an area measuring 12 miles from north to south and seven miles from east to west, the boundary of which passes through Craven Arms, Ludlow, Aymestry, and Leintwardine.

The limestone was named by Murchison in 1839, after the village of Aymestry, in the neighbourhood of which it is well exposed, and since that date no detailed work has been done on it.

In 1900 Dame Ethel Shakespeare (then Miss Wood) described the Lower Ludlow shales, and in 1906 Miss Elles and Miss Slate described the beds lying above the limestone in parts of the area here described. The later paper contains an excellent summary of all the work done in the neighbourhood up to 1906.

III. Detailed Description of the Aymestry Limestone

(a) Lithology

Three lithological types are found in the Aymestry Limestone. The most common is a fine-grained, massive or nodular, blue-grey limestone occurring in beds of from one to three feet in thickness, separated by greenish calcareous shales in bands from a half to six inches thick. The fossils in this type of limestone are complete, the valves of the brachiopods being still articulated, and many specimens are still apparently in the position of growth. Fossils are more or less evenly distributed throughout, the rock and there is no sorting, as in the second form of the
The non-Marine Lamellibranchs of the North Wales Coalfield
Authors: Wood Alan
Published: October 2009

In the recent correlation of the Upper Carboniferous of England and Wales published by Professor A. E. Trueman (1933) the most obvious omission was a consideration of the North Wales coalfield. At that time, indeed, only three lamellibranch species had been reported from the area. In the present paper knowledge of the fauna is extended and the modern zonal scheme is applied to the coalfield. The floral zones recently introduced by Dr. E. Dix (1934) can be partially distinguished in the area, but these form the subject of a separate paper (Wood 1936b). The results are in accord with those based on the lamellibranchs.

The area dealt with is shown on the map (Fig. 1), while the relationship of the lamellibranch zones and the coal-seams can be seen from Fig. 8.

The Geological Survey memoirs dealing with the coalfield (Wedd & King 1924; Wedd & others 1923, 1927) contain little account of the fauna of the Coal Measures.

The shell
Carbonicola robusta
(J. de C. Sowerby) (sic) was recorded from above the Main Coal at Mancot, near Hawarden, and was considered to indicate the Lower Coal Measure age of this seam.
Anthracomya calcifera
Hind was collected from the Upper Coal Measures to the south of Ruabon, while this shell and
A. phillipsi
(Williamson) were found in the Upper Coal Measures south of the Dee, outside the limits of the area dealt with in this paper. No other records were published, and shells were stated to be rare in the Coal Measures
The Carboniferous Limestone of the Mitcheldean Area, Gloucestershire
Authors: Sibly Thomas Franklin , Reynolds Sidney Hugh
Published: October 2009

At the north-east comer of the Forest of Dean coalfield, immediately west of the village of Mitcheldean, the strata are sharply folded into a pitching syncline—the Wigpool syncline —which tapers out northwards and merges southwards into the main basin of the coalfield. Here the Carboniferous rocks form a triangular plateau which rises sharply from the Old Red Sandstone country. The Carboniferous Limestone of this small area, measuring some two miles from north to south and a little over one mile in maximum width from east to west, is the subject of the present paper. The strata are remarkably well exposed in numerous quarries, and the succession can be studied in almost complete detail.

The following lithological classification of the Lower Carboniferous rocks in the Forest of Dean was proposed in 1919:—
1

This series of strata rests conformably upon the Old Red Sandstone, but it is overlain unconformably by the Coal Measures.

Wethered had dealt with the strata and fossils of the Carboniferous Limestone near Mitcheldean in three papers published during the period 1883–88, while Vaughan published in 1905 a brief account of the sequence and a zonal correlation, and demonstrated the Lower Carboniferous age of the local “Millstone Grit”. In 1912, one of us gave some further account of the succession, described the unconformable relationship of the Lower Carboniferous strata and the Coal Measures, and proposed the name Dry brook Sandstone for the “Millstone Grit”. In 1918, the S
2
age of the Drybrook Sandstone was definitely established by the discovery of
A Fabric Study of some Moine Schists and Associated Rocks
Authors: Phillips Frank Coles
Published: October 2009

The science of
Gefügekunde
, variously translated as petrofabrics, petrotectonics, or structural petrology, is understood to comprise a study of all the spatial data, macroscopic and microscopic, which go to form a complete vector-picture so far as this is legible in the make-up of the rock. This conception of a fabric thus covers both texture and structure, and is an extended usage compared with that of the C.I.P.W. classification (Fairbairn 1935a, p. 4). A complete fabric study involves as an essential preliminary a study in the field of the macroscopic fabric—joint-planes, schistosity, and similar features—but the subsequent microscopic analysis of the grain-fabric provides a basis on which these features may be evaluated. The early analyses were laboriously carried out with the help of a gypsum plate, and detailed optical study dates from Schmidt's first attempt (Schmidt 1925) to put into practice a suggestion by Becke (1924, p. 207) that such optical analyses might conveniently be carried out with the help of the universal stage. Schmidt's paper gives a clear description of the procedure, which is also fully described by Sander (1930, pp. 118–30). Many later papers in English begin with a short account of the methods (Pabst 1931, pp. 60–3; Gilluly 1934, pp. 185–8), and a full account is given by Fairbairn (1935a, pp. 9–25).

The value of such fabric analyses is threefold. First, from a purely petrographic view-point, they enable one to give a more complete description of a rock—"it is a totally different thing to talk about a granite
Petrographic Description of Volcanic Rocks from Turkana, Kenya Colony, with notes on their Field Occurrence from the manuscript of Mr. A. M. Champion
Authors: Smith Walter Campbell
Published: October 2009

The province of Turkana in Kenya Colony comprises a tract of country west of Lake Rudolf bounded on the north by the Anglo-Egyptian Sudan and on the west by Uganda. It covers an area of about 27,000 square miles, and until recently the geology was entirely unknown. During his term of office as Provincial Commissioner, Mr. Arthur M. Champion surveyed the country and made a large collection of specimens of rocks and careful observations on the geology, particularly the physical geology, of the region.

During his administration, Turkana was visited by two scientific expeditions, one under the leadership of M. C. Arambourg in 1932–3, and one led by Dr. V. E. Fuchs in 1934. M. Arambourg's expedition was directed mainly towards the investigation of beds rich in mammalian remains, discovered in 1902–3 during the expedition of le Vicomte Robert du Bourg de Bozas in the lower part of the valley of the Omo at the north end of Lake Rudolf. In the course of the expedition he made some observations on the volcanic rocks, and the petrography of his specimens has been written by Mme E. Jérémine (1935). These specimens I was privileged to study in the Mineralogy Department of the Muséum national d'Histoire naturelle at Paris in the spring of 1937 by the courtesy of Professor Orcel and Mme Jérémine.

An account of Dr. Fuchs's expedition has been published (1935) and the geological results will be available shortly. I have been privileged to examine his specimens, but although he
The Stratigraphy of the Wenlock Limestone of Dudley
Authors: Butler Arthur James
Published: October 2009

The Wenlock Limestone of the three small inliers of Salopian rocks which occur in South Staffordshire and the detached parts of Worcestershire near the town of Dudley has long been famous for the rich variety of its fossils. Dr. Plot figured some of these in 1686, and two hundred and fifty years later Professor Gignoux writes of “le petit affleurement de Dudley (calcaire de Dudley) qui a enrichi les collections du monde entier”. To quote Charles Lapworth: “It may be safely asserted that the majority of the finest examples of British Silurian fossils now enriching the public and private geological collections, both in Britain and abroad, were originally obtained from the Silurian rocks of the Birmingham district;” and the Wenlock or “Dudley” Limestone is by far the most fossiliferous division of these rocks. It has yielded numerous type specimens, including many of those described in
The Silurian System
, but in spite of the importance of the outcrops from the view-point of palæontology, and of the countless maps which were made of them by successive generations of students under Lapworth, detailed stratigraphical literature is scanty. Since the time of Murchison no publication has greatly supplemented the description contained in
The Silurian System
(1839, pp. 483–7), though a later account, containing a faunal list, was given by J. B. Jukes in his memoir of the South Staffordshire coalfield (1859, pp. 106–17), and brief but vivid reviews of the stratigraphy and structure of the outcrops were included in papers on the geology of
The Ammonite Succession at the Woodham Brick Company's Pit, Akeman Street Station, Buckinghamshire, and its bearing on the Classification of the Oxford Clay
Authors: Arkell William Joscelyn
Published: October 2009

The Woodham Brick Company's pit was opened in 1936, about midway between Aylesbury and Bicester, on the north-east side of Akeman Street Station (L.N.E.R.). It lies four miles south-south-east of the brickfield in Kosmoceras Shales of the Lower Oxford Clay at Calvert Station, and 2¾ miles north-north-east of the G.W.R. cuttings at Rushbeds Wood, near Ludgershall, and between Ashendon and Dorton, where Upper Oxford Clay and Ampthill Clay were recorded (Davies 1916). Some of the railway-cuttings appear to have exposed almost the same beds as are now displayed at the Woodham pit, but they were partly sloped before examination, and no description of the succession or faunas was published. The brick-pit now described, therefore, is the first extensive exposure of the middle and the lower part of the Upper Oxford Clay in middle England from which fossils have been collected bed by bed. Its interest is exceptional, owing to the great abundance of well-preserved ammonites, of which up to the present more than 1250 specimens, belonging to 70 species, have been collected. Many species known hitherto only from the Hackness Rock of Yorkshire, or from the Oxford Clay of Dorset, France, or the Jura Mountains, occur here in association; and it has been possible to determine the horizons of nearly all of them. The material is used as the basis for the first attempt at a review of British Oxford Clay ammonites. The pit is at present (1938) about 70 feet deep, in nearly flat-lying beds. The highest 19 feet
The Petrography of the Permian Rocks in the Southern Part of the Vale of Eden
Authors: Versey Henry Cherry
Published: October 2009

I.
Introduction

The Permian rocks of the Vale of Eden are readily divisible into two areas contrasting in their lithology. The main part of the valley shows a development of the well-known Penrith Sandstone, but south-east of a line drawn from Dufton to Grackenthorpe this sandstone is replaced by thick breccia —the Brockrams—until near Winton, south of Brough-under-Stainmore, it almost disappears. In this southern portion of the area the Penrith Sandstone is covered by plant-bearing beds, the Hilton Plant Beds, and a magnesian limestone. To the west, the Permian rocks rest uncomformably on Lower Carboniferous strata, while to the east they are covered with apparent conformity by Triassic rocks, although locally there is evidence of overlap or even unconformity. Detached masses of Permian material are found in the broken ground along the Outer Pennine Fault near Long Fell and Kirkland. The type section in this southern area is taken, following Harkness (1862, p. 207) and Goodchild (1893), in Hilton Beck and the country on the opposite bank of the Eden. The succession here is as follows:—

This general succession may be traced to the south-east as far as the River Belah, but in this distance the breccia beds thicken at the expense of the sandstones. South of the Belah section the Hilton series disappears, but at Merry Gill Viaduct, near Kirkby Stephen, a magnesian limestone, full of pebbles, occurs. The whole of the Penrith series suffers considerable diminution in thickness. To the north-west the Hilton Beck succession may be traced as
The effects of frost action and solifluxion around Baffin Bay and in the Cambridge District
Authors: Paterson Thomas Thomson
Published: October 2009

These studies constitute part of the geographical results of the Wordie Arctic Expedition, led by Mr. J. M. Wordie of St. John's College, Cambridge, to Melville Bay and the east coast of Baffin Land in the summer of 1934.

It was found that some of the arctic soil forms had strong similarities to structures observed in the Pleistocene gravels of the Cambridge area, and that, treated together, these forms and structures would throw new light on the mechanics involved in their formation.

The studies are divisible into three portions: frost cracking, polygonal structures, and solifluxion.

I. Frost Cracking

Travellers in northern and eastern Siberia report that the tundra, in places, is scarred and seamed by ramifying linear depressions flanked by low ridges, the depressions being marked out by a darker growth of mosses, generally interlacing to form roughly polygonal features many feet across. They have not, so far as is known, been excavated (Sukatchev 1911, Nikoroff 1928).

Leffingwell (1919) observed frost cracks occurring in Alaska only in “muck”, though Smith (1909, p. 272), writing on the Nome deposits, noted a “series of ramifying streaks of a black peaty material cut in irregular directions across the layers of sand and gravel”, which streaks he attributed to frost cracking. Leffingwell (1919, p. 211) also noted “frequently straight lines leading across the gentle undulations of sandspits”, though he saw no polygonal forms in such places. However, his classic treatment of the theory of the formation of ground ice led him to generalize on
On peneplains and related land forms
Authors: Martin Edward A.
Published: October 2009

After reading Dr. Dixey's remarks and the discussion that followed, one wonders if there is any place for the word “peneplain” in geological language. There appears to be no agreement as to what constitutes a peneplain, opinions expressed being extremely diverse. Many years ago Dr. A. E. Salter introduced the word in a paper, and Professor Bonney then expressed doubt of the need for it, calling it, I think, a “mongrel” word which nobody understood. We do not seem to have advanced very far beyond this, and if we cannot agree as to its meaning, is it desirable to retain the word? The main point of agreement seems to be that the plain must be of subaerial origin. Dr. Wooldridge rightly refers to a peneplain as defined by W. M. Davis as a rolling lowland with unconsumed residuals, or as “conjecturally restored by the linking of isolated hill-summits”, brought about by the “wasting of divides”. If a peneplain be but a plain reduced nearly to sea-level, why call it anything but a lowland plain? If the term is to be retained it seems to be best applied to the relics of a former plain restored in imagination from the summits of mountains linked up, although surely these summits have also been reduced, and the “fossil” plain must have been a good deal higher.
The Borrowdale Volcanic Series of Coniston, Lancashire
Authors: Mitchell George Hoole
Published: October 2009

I. Introduction

The Furness Fells lie at the extreme northern corner of Lancashire between the higher reaches of the River Duddon and the upper end of Lake Windermere. The highest summits are those of Wetherlam (2502 feet), Swirl How (2630 feet), Brim Fell (2611 feet), Old Man of Coniston (2633 feet), and Dow Crag (2555 feet). These are but the most prominent peaks on a high ridge extending from north-east to south-west. This watershed divides the waters which flow westwards to join the Duddon and northwards to the Brathay from those which find their way south-eastwards into Coniston Lake. From north to south there are six principal becks which, rising near the watershed, make their way ultimately to Coniston Lake. In the north Tilberthwaite Gill descends through its picturesque gorge along a course which is nearly northward in direction as far as Tilberthwaite, where, turning abruptly south-east and then south-west, it becomes known as Yewdale Beck, thereafter forming a strike stream almost along the junction between the Borrowdale Volcanic and later rocks. Approaching Coniston it again turns south-eastwards over the low ground to the lake. Church Beck is formed by the gathering together of a bunch of tributaries which are known as Red Dell Beck, Levers Water Beck, draining the tarn of that name, and Low Water Beck, which issues from Low Water. These all descend in marked steps to the Coniston Copper Mines, below which the main stream of Church Beck descends by a further succession of falls to
The Killough-Ardglass Dyke Swarm
Authors: Tomkeieff Sergei Ivanovich , Marshall Charles Edward
Published: October 2009

I. Introduction

The dykes described in this paper are those occurring on the coast of County Down, Northern Ireland, between Killard Point in the north and Inner Dundrum Bay in the south-west (Pl. XX); the length of coast-line is approximately 20 miles.

The country rock of the district is entirely of hard, compact Lower Palaeozoic grits and slates, highly folded and faulted and considerably affected by glacial action, which tend to give a very bold and rugged shoreline. Exceptions occur in only one or two places; Ballyhornan Bay is occupied by a wide stretch of sand with few rock exposures; Dundrum Bay includes a very long stretch of sand with few outcrops of solid rock. The fact that a number of dykes are found in the few outcrops that are exposed in these covered stretches suggests that the solid rock concealed by the sand may contain many more.

South of Dundrum Bay, the Palaeozoic grits and slates again rise above tide-level and the rocky coast-line is traversed by the numerous dykes of the Mourne swarm, which have already been described by the present authors (1935). In the same paper the geographical relations of the dyke swarms of the Tertiary Province of Northern Ireland have been discussed, and consequently need not be referred to here.

The first survey of the dykes of this swarm was completed by Traill and Egan (1871), who gave a brief account of some of the dykes. No further attention appears to have been given to the
The Garabal Hill-Glen Fyne Igneous Complex
Authors: Nockolds Stephen Robert
Published: October 2009

I. Introduction

The Garabal Hill-Glen Fyne igneous complex lies just west of the head of Loch Lomond and stretches westward into Glen Fyne. The complex occupies an area
of some 12½ square miles embraced by sheets 37, 38, 45 and 46 of the one-inch Geological Survey map of Scotland. It breaks through various Dalradian schists already folded and regionally metamorphosed and these suffered thermal metamorphism when the rocks of the complex were intruded. The age of the complex is generally accepted as Lower Old Red Sandstone, owing to its close resemblance to other igneous masses of that age in Scotland.

The earliest account of the area is given by Dakyns and Teall (1892) in a paper which has since become classical. The boundaries of the massif were accurately delineated, some of the rock types were mapped, briefly described and chemically analysed, and the hypothesis put forward that they had been derived from some parent magma by a process of differentiation operating at depth. A description of part of the western portion of the mass and of the thermal metamorphism induced there in the surrounding schists was published in the Cowal Geological Survey memoir (1897, pp. 96–101) and in the mid-Argyll memoir (1905, pp. 92–3). Finally, a paper by Wyllie and Scott appeared in 1913, dealing mainly with the ultrabasic rocks of the complex but including some data on the basic and intermediate rocks. The variation in the ultrabasic and dioritic rocks was ascribed to local variation
A gabbro-granodiorite contact in the Slieve Gullion area and its bearing on Tertiary petrogenesis
Authors: Reynolds Doris L.
Published: October 2009

In the Slieve Gullion area, Northern Ireland, gabbro occurs in association with each of the two Tertiary structural units, namely : (1) the Ring Complex and (2) the north-westerly extending granophyre mass which Richey (1932, p. 782 and pl. lv) has termed the North-West Belt. In addition, a small gabbro plug outcrops on the lower northern slopes of Camlough Mountain. With the exception of the intrusions associated with the Ring Complex, the gabbro masses have all been shown to be of Tertiary age. Evidence of the Tertiary age of the Camlough Mountain plug was presented by Richey and Thomas in 1932, whilst the Tertiary age of the gabbros associated with the North-West Belt was demonstrated by the writer in 1937. The discovery that the emplacement of the gabbros of the North-West Belt was accompanied by the metasomatism and rheomorphism of the Caledonian granodiorite of the Newry Complex (Reynolds 1937) suggested the possibility that Richey and Thomas might have misinterpreted the evidence from which they inferred a Caledonian age for the gabbros associated with the Ring Complex. A detailed investigation of the contact of one of these gabbros has therefore been undertaken, and the objects of the present communication are (a) to present evidence that the gabbros associated with the Ring Complex are, like those of the North-West Belt, of Tertiary age, and (b) to record the details of the stages whereby Caledonian granodiorite, at its contact with Tertiary gabbro west-south-west of Mullaghbawn Mountain, has become transformed to rock of Tertiary
The Lundy Complex: Its petrology and tectonics
Authors: Dollar Archibald Thomas John
Published: October 2009

The Lundy igneous complex projects through the Palaeozoic floor of the Bristol Channel at a point 24 miles due west of Ilfracombe, North-West Devonshire. Its subaerial part lies about the intersection of parallel 51° 11′ N., and meridian 4° 40′ W.

Unique alike in structure and composition among insular masses of the Severn estuary, it affords evidence of former crustal weakness and associated vulcanicity in a region situated near both the northern boundary of the Cornubian Permo-Carboniferous igneous province, and the southern boundary of the Hebridean Tertiary igneous province.

It is a composite block of alkaline granites intruded among contorted slates, altered calcareous grits and thin marbles, with a swarm of basic, intermediate and acid dykes cutting both granites and sediments in a dominantly north-westerly direction. Erosion of the resulting complex has reached a stage such that only Lundy Island, the central and eastern part of its rugged core, now remains above sea-level. This core rises abruptly from an irregular base of uncertain submarine extent to a maximum height of 47·5 feet above mean sea-level. From north to south its subaerial length is 3·1 miles; its average width is 0·6 miles, and its superficial area is nearly 1·7 square miles. Of the subaerial volume approximately 91·4 per cent is granite and microgranite; 6·4 per cent is altered sediment and 2-2 per cent is dyke-rock. The island is surrounded by an indented shore-line with steep cliffs, the latter being united to an undulating table-land at 350 feet above mean tide-level by
The gastropods of the Purbeck Beds
Authors: Arkell William Joscelyn
Published: October 2009

Isolated occurrences of genera such as
Viviparus
and
Valvata
are known in Bathonian, Liassic and more doubtfully even earlier rocks, but the earliest assemblage of a dozen genera of unequivocally freshwater molluscs is found in the wonderful fauna of the Purbeck Beds. Attention was first called to it by Thomas Webster (1816, pp. 191–2) (see below, p. 81). His remark, “It is rather surprising that this very ancient freshwater formation should not have excited more attention,” might almost be said to be still true; for since J. de C. Sowerby figured a couple of species of
Viviparus
from the Purbeck Beds in 1826 and six species of lamellibranchs in that year and in 1836 (in Fitton's memoir), no further Purbeckian mollusca have. been adequately figured in this country or described in the English language.

Edward Forbes was preparing a monograph on the invertebrate fauna of the Purbeck Beds when his work was cut short in 1854 by his death at the age of 39. All that appeared was a preliminary account, in which the genera
Viviparus, Valvata, Lymnaea, Planorbis, Hydrobia, Physa, Melania, Cyclas
, and
Unio
were recorded, and also many marine genera, but no species were mentioned. A number of MS. names were introduced by him on labels and in the Survey catalogues, and some of them have been used by other authors, but if any manuscript or type specimens existed they have disappeared.

In 1856 Osmund Fisher published a detailed account of the stratigraphy of the Dorset Purbeck Beds
The structure of Gower
Authors: Neville George T.
Published: October 2009

I feel I cannot let Professor George's paper pass without raising my voice in protest, however feeble, against his introduction of the term “strike-slip” in place of “tear-fault”.

As long ago as 1925 J. W. Evans (
Q.J.G.S.
lxxi, p. lxxx) used the term “slip” or “slip-fault” for a tensional fault due to vertical forces; and in this sense the term was perpetuated by the present writer (
Geol. Mag.
lxvi, 1929, pp. 345-7). Professor George now proposes to use the word in a totally different sense for a purely horizontal movement, and in doing so gives us no less than seven different names for the same thing—tear-fault, strike-slip, transcurrent fault, transverse thrust, wrench-fault, flaw and the German "blatt". Several other terms have also been used which have not come into common usage in this country.

The “strike-slip” of a fault was a term introduced by American authors and perpetuated by Challoner (
Geol. Mag.
lxx, 1933, p. 386) and others in this country for a definite measurement on the fault surface, representing the resolved component along the strike of the fault of a movement which had taken place not in the direction of the maximum dip of the fault, but obliquely to it. Its use as descriptive term for a class of faults showing horizontal movement only is to be deprecated, and more especially so as the strike-slip refers to the strike of the
fault
, whereas the ordinary terms “dip-fault” and “strike-fault” refer to the dip and strike of the
strata
.

I
Stratigraphy and Structures East of Oxford
Authors: Arkell William Joscelyn
Published: October 2009

I. I
ntroduction

T
he
Geological Survey 1-inch map of Oxford (1908) shows to the east of the city a remarkable belt of faults, running from north-west to southeast for 12 miles and passing at its nearest point within three miles of Magdalen Bridge. Starting in the Great Oolite and Forest Marble of Islip, the faults cut through the Corallian rocks between Elsfield and Beckley and bound the Corallian limestones of Wheatley. They also shift the Kimeridge Clay, Portland Beds and Shotover Sands of Forest Hill, Great Milton and Great Haseley, as far as the margin of the overstepping Gault.

Closer inspection of the map makes it clear that these are by no means simple faults. In fact, no satisfactory interpretation of the structure is possible from the arrangement of outcrops and faults shown on the map. The explanatory memoir (1908), by T. I. Pocock, H. B. Woodward, and G. W. Lamplugh, contains no chapter on structural geology. There are, however, scattered references to structure in the stratigraphical chapters, and these were reproduced without alteration in the second edition (Pringle 1926 1). The authors referred to trough-faulting with displacements of 200 feet and 80 feet, to step-faulting, and to a " general Hne of fracture and displacement " which " owing to the meagre field-evidence, could not be deciphered in detail ". No mention was made of folding, and for the most part the mapping shows that none was envisaged.

In the light of experience gained in mapping other “lines of
The algal nature of the genus
Koninckopora
Lee; its occurrence in Canada and western Europe
Authors: Wood Alan
Published: October 2009

I. I
ntroduction

D
uring
investigations in the Windsor Limestone (Mississippian) of Cape Breton Island, Nova Scotia, a striking tubular bed was discovered. Sections of these bodies (PL IX, fig. 1) showed them to be partly composed of a complex calcareous alga apparently new to science. The same species was discovered by the author in a collection from the Cracoe district of Yorkshire made by Mr. G. Bond, and further research proved it to be widespread in England. Search through the literature dealing with corals and bryozoa revealed that this form had been described as a coral by de Koninck in 1842, and made the type of a new bryozoan genus
Koninckopora
by Lee in 1912. During the present investigation over 75 microscope slides of
Koninckopora
have been studied and all available material has been examined.

Much kind help has been received during this investigation. Mr. W. N. Edwards of the British Museum stimulated the work by his interest and allowed me to borrow the specimens of
Koninckopora
under his charge, Professor W. F. Whittard generously sent the whole of the S. H. Reynolds collection of rock sections for inspection, Mr. T. A. Jones of Liverpool permitted me to go through his collection of slides and borrow many of them, and Mr. G. Bond of the Imperial College collected specimens from Cracoe and showed where they occurred in

The visit to Canada was only possible through the aid of the Tyrrell Fund of the Geological Society of London, while many of the
Intrusive rocks of the Shelve area
Authors: Blyth F. G. H.
Published: October 2009

In the discussion on the above paper Professor W. G. Fearnsides said that the " abundance of separated jointed blocks and heavy scree on the south-east side [of Corndon Hill] and comparative absence of litter towards the west required an explanation ". To the writer this appears to be a geomorphological problem directly related to the glacial conditions which prevailed during Pleistocene times, an aspect which was not discussed at the reading of the paper.

The distribution of drift in the Welsh Borderland has much in common with that of the Isle of Man, both local and extra-insular drift being involved. In the words of Lamplugh (Geol. Surv. Mem. Isle of Man, 1903, p. 352), "Their relative distribution is everywhere in keeping with Mr. Kendall's supposition that only the lower layers of the ice-sheet were drift-laden, and that these were diverted by the steeper hill slopes and swept round the flanks of the massif as an undercurrent."

Applying this principle to the Shropshire area, it is clear that hills such as Corndon and the Breidden, to select two examples, must for long have remained as outstanding
nunatakkr
similar to those of the Nordenskiöld Glacier of Spitsbergen at the present day. Their western or ice-ward flanks were directly exposed to the oncoming Welsh ice, although the pure upper ice would have little abrasive power. The eastern or leeward flanks were zones of pluck, a process responsible for the disintegration and removal of the rock-face from top to bottom during the progressive
The stratigraphy, structure and mineralization of the Greenhow mining area, Yorkshire
Authors: Dunham Kingsley Charles , Stubblefield Cyril James
Published: October 2009

The primary object of the work was the investigation of the geological environment of the galena-fluorite-barite deposits. The Carboniferous Limestone Series, over 1400 feet in maximum thickness, was mapped in six divisions covering faunal horizons from ?C
2
S
1
up to and possibly above D
2
. The Millstone Grit Series rests unconformably on horizons from the
Davidsonina
[
Cyrtina
]
septosa
band in D
1
up to beds with
Orionastraea
, the relations being ascribed to a pre-Millstone Grit uplift, possibly domal in form, accompanied by faulting. Within the Millstone Grit the "Top Limestone" (renamed the Cockhill Limestone) was proved to be characterized by
Cravenoceras cowlingense
(E
2
). Two higher marine horizons, well known elsewhere, were established here by many exposures : the Colsterdale Marine Beds, characterized by
Cravenoceras nitidum
(E
2
), seen in the same section as the Cockhill Limestone, and the glauconitic Cayton Gill Beds. A structure-contour map based on horizons in the Millstone Grit mapped at surface and underground shows that the anticline in the southern part of the area, trending east-north-east, has an amplitude of about 1000 feet, and that a series of domes and basins have been developed along its crest. The North Craven Fault, runniilg along the southern flank of the anticline, is a complex fracture-belt enclosing a tight syncline in the western part of the area, degenerating eastwards into a small strike-fault. The eastern half of the Bycliffe Vein-system is mineralized up to the Cayton Gill Beds but the remaining veins are mineralized only in the Carboniferous Limestone. The most important ore-shoots are found in the upper division of D
l
, in limestone underlying either shales low in the local D
2
or the basal shale of the Millstone Grit, depending on the position of the unconformity. Less important ore-shoots are found at various horizons from ?C
2
S
1
up to D
1
. It is suggested that extension of mineralization in depth beyond the limits so far revealed is possible in the case of ore-shoots related to shale overlying D
1
limestone. There is a crude zonal arrangement of minerals. Palaeontological notes are included on
Hederella
cf.
chesterensis
(of a suborder new to Britain) and on two new forms,
Productus (Eomarginifera) tissingtonensis cambriensis
and
Eumorphoceras bisulcatum grassingtonensis
.
The Arvonian rocks of Arvon
Authors: Greenly Edward
Published: October 2009

The Arvonian formation consists, in situ, of a granite, a quartz-rhyolite, and a pyroclastic series, but other members were formerly present. The granite, very coarse at Caernarvon,
1
slowly grows finer eastward, until it graduates into the rhyolite. There are coarse agglomerates, and three groups of finer tuffs. In all, nine members can be distinguished, and there is an order of superposition. Is the formation Cambrian, or is it somewhat older, with a measure of unconformity ? Balance of evidence seems to be in favour of unconformity. Correlation is considered, though very cautiously, with Uriconian and Pebidian.

The term " Arvonian " was proposed by the author in 1930 (
Geol. Mag.
lxvii, 1930, p. 287) to denote the ancient volcanic series of the country between the Menai Strait and Snowdonia, which comprises the well-known rhyolite of Llyn Padarn, the rhyolite between Bangor and Caernarvon, and the pyroclastic rocks of Bangor itself. When originally described, the formation was referred to as the " Bangor Volcanic Series ", but in the course of the recent detailed survey it was found to be very much more extensive than was formerly recognized, occupying indeed as much of Arvon as its other three major formations combined (Fig. 1). The thickness of the Arvonian formation is great, and its importance in the early volcanic history of Britain is second only to that of the Mona Complex.

The formation appears to be entirely igneous, for no sedimentary rocks have been found. In situ at the present time it
On some new Permian fossils from the Magnesian Limestone near Sunderland
Authors: Trechmann Charles Taylor
Published: October 2009

Practically all the species of invertebrates in the Permian of England had been discovered before 1850, almost the only exception being the record of
Chonetes davidsoni
in 1864, from the Lower Magnesian Limestone at Hartley's Quarry west of Sunderland. The present paper deals with some new occurrences in these beds rather farther to the west, at Ford Quarry, Claxheugh, 2 miles west of Sunderland. They include two new species of
Chonetes
, one of which resembles a Spitsbergen form, a
Camarophoria
apparently identical with
C. purdoni
of the Russian and Himalayan Permian, and at least two lamellibranchs with Russian and German affinities. The early collectors paid little attention to the vertical or lateral distribution of their fossils; in the middle beds most of the fauna is crowded in a line of reef knolls in which the species die out progressively upwards. Among other localities, the classical knoll of Humbleton Hill has been re-examined, and at the top, facing west, a dolomite with the impoverished fauna, only three genera of Brachiopoda, has been found. The thrusts and other abnormal junctions of the Permian of North-East Durham have been re-investigated and their possible connexion with solution of sulphates and with faunal and reef-knoll distribution is mentioned.