bluuebunny/crossref_metadata_2025 huggingface dataset:
The Carboniferous Limestone Series in the West of the Vale of Glamorgan
Authors: George Thomas Neville
Published: October 2009

I. Introduction and Historical Notes

The deposits that are present over the greater part of the Vale of Glamorgan consist of a more or less thick covering of Mesozoic (Triassic, Rhætic, and Lower Liassic) rocks through which extensive inliers of Upper Palæozoic strata emerge. The latter are chiefly of Avonian age, and constitute fragments of the southern arc bounding the syncline of the South Wales coalfield.

The present paper is concerned with those Lower Carboniferous inliers, lying to the west of the River Ddawan, that form the tracts of down county in the neighbourhood of Porthcawl, Bridgend, and St. Bride's Major, and which are a continuation of the series of folds comprising the Cardiff-Cowbridge anticline (see fig. 1).

The area lies wholly within the 1-inch (New Series) Geological Survey map no. 261–2, and was described by the officers of the Survey in the memoir (‘The Country around Bridgend,’ 1904, p. 13) accompanying that map. It is the purpose of this paper to supplement the information contained in the memoir with an account of the zonal sequence and of the structures elucidated by the application of the stratigraphical details obtained. It will be obvious that the work is based to a very great degree upon the publications of the Geological Survey; my indebtedness to them is considerable, especially as regards the construction of the map.

Apart from the information contained in the Survey Memoir, which almost entirely relates to the lithology, a brief note by Sibly (1920, p. 90) is the
On the Occurrence of Tremadoc Shales in the Tortworth Inlier (Gloucestershire)
Authors: Smith Stanley
Published: October 2009

I. Introduction

The presence in South Gloucestershire of rocks older than the Old Red Sandstone was made known more than a century ago by the researches of W. Buckland and W. D. Conybeare (1824, p. 216) and T. Weaver (1824). Murchison included them in his Silurian system (1839, pp. 447–9, 454–62, and map separately issued), utilizing, in addition to his own observations, notes and sketches made by the Rev. George Cooke, Rector of Tortworth at that time.

The area was mapped by D. Williams, J. Phillips, A. C. Ramsay, and H. W. Bristow of the Geological Survey during the directorship of De la Beche, and the information was published in 1845 (Geological Survey 1-inch Map, Sheet 35). Bristow revised this part of the sheet in 1865, and further information was added to the map in 1866.

John Phillips (1848, pp. 190–8 & pl. i) gives a good account of the Palæozoic inlier, and H. B. Woodward includes a shorter and less accurate description of the beds in his memoir on the Bristol coalfield (1876, pp. 9–11 & pl. i).

Within recent years, S. H. Reynolds, partly in collaboration with C. Lloyd Morgan and F. R. C. Reed, has written a series of papers dealing with the geology, petrology, and palæontology of the southern part of the outcrop, and has summarized the results in his ‘Geological Excursion Handbook for the Bristol District’ (1912 & 1921, pp. 200–9). Nothing, however, has been published about the northern part (that is, the country north
The Sandfell Laccolith and ‘Dome of Elevation’
Authors: Hawkes Leonard , Hawkes Hilda Kathleen
Published: October 2009

. Introduction

The eastern part of Iceland is built mainly of a great series of plateau basalts dipping at low angles to the west, and the structure is magnificently exhibited in the sides of the deep valleys and fjords which incise the 3000–4000-foot plateau. The traveller is impressed by the constancy of the almost flat-lying trap featuring, which persists in the region of the ‘stock’ intrusions to the south (Cargill
et alii
, 1928), so that Sandfell, a hill of light-coloured rock on the south side of Faskrudsfjord, at once attracts attention because the basalts are disposed at high angles in proximity to it—a circumstance which was noted by Thoroddsen (1906, pp. 268, 277). The hill is a splendid example of a laccolith similar in type to those of the Henry Mountains, Utah, and equally impressive in its exposure. The combination of conditions which made the intrusions of the Henry Mountains the type of their class is present here—approximately level strata, intense erosion, and absence of vegetation (Gilbert, 1877, p. 97). The main hindrance to the complete elucidation of the structure is the extensive screes—to which Sandfell owes its name.

This paper is based upon field investigations made on four visits between 1914 and 1932. In the earlier stages of the work snow-drifts hid some of the higher parts, but there has been a marked amelioration of climate in latter years, and in August 1932 all the drifts had disappeared. The district is unmapped, and in 1928 the second author made
The Corallian Rocks of the Howardian Hills (Yorkshire)
Authors: Wilson Vernon
Published: October 2009

I. Introduction

In north-eastern Yorkshire, the gritstones and limestones comprising the Corallian sequence occur flanking the greater part of the Vale of Pickering. From the coastal districts about Filey and Scarborough they extend westward, forming a broad belt of flat-topped hills, the Tabular Hills, and terminating in the magnificent escarpment of the Hambleton Hills overlooking the Vale of Mowbray. To the south-west, the continuity of outcrop is broken by the Coxwold-Gilling rift which intervenes between the Hambleton Hills and the Howardian Hills, the latter lying to the south-east. It is the area of the Howardian Hills which forms the subject of the present communication.

The lower ground between the rift faults is occupied by low hills of Kimeridge Clay, covered to varying degrees by glacial drift, but an area of Corallian rocks forms a prominent ridge between Coxwold and Kilburn.
About 3½ miles east of Coxwold, the Corallian appears in Gilling Park, and from thence extends as a low ridge in an east-south-easterly direction through Malton to the vicinity of North Grimston, where it becomes lost under the Cretaceous overstep. The strata in this area have commonly a low dip to the north, but the presence of an intricate system of faults causes local modification in the dip and distribution of the rocks and complicates the stratigraphy. The northern boundary of the Corallian is determined by the main Gilling fault, though for the most part its course is obscured by drift. Besides the main line of outcrop, areas of Corallian
Report on some Fossil Plants Collected in Tanganyika Territory
Authors: Robertson Lesley Stuart
Published: October 2009

The plant impressions described below were collected last year by Mr. G. M. Stockley from the Karroo formation in the Upper Gombati River, just below the Lukensi Mountain, Tanganyika Territory. They were sent to Prof. J. Walton for identification, and by him were kindly given to me to describe. The collection includes several specimens of
Glossopteris
fronds and equisetaceous stems, and is now included in the Hunterian Museum Collection in the University of Glasgow.

Glossopteris

Specimens of pale clay shale from the Kidodi area were found to contain several fragmentary impressions of fronds of
Glossopteris
, among which two different species have been identified.

Glossopteris Conspicua Feistmantel

(Nos. 1205-1208)

This relatively uncommon species has a wide-meshed venation; the network formed by the secondary veins is very large and open. The meshes are polygonal, very much longer than broad, and of approximately the same size throughout the lamina. Figure 1 shows a fragment of the lamina, 5 cms. in length, in which the midrib is distinctly visible. The largest of the fragments shows that the lamina is at least 7 cms. broad. In Fig. 2 the regular form of the venation can be seen. On comparison with other known species of
G. conspicua
, these fragments are found to agree very closely with those from the Damuda Series of India figured by Feistmantel (1881, pl. xxviii A, fig. 5), and also with one from the Orange River Colony figured by Arber (1905, pl. iii, fig. 3).
Glossopteris conspicua
has also been recorded from
The Lower Palæozoic Rocks of Austwick and Horton-in-Ribblesdale, Yorkshire
Authors: King William Bernard Robinson , Wilcockson William Howson
Published: October 2009

I. Introduction

The area dealt with in this communication is one of the small exposures of Lower Palæozoic rocks forming part of the edge of the rigid block which, near the Craven faults, appears from beneath the great spread of almost horizontal Carboniferous strata of the Mid-Pennine area. The late Prof. J. E. Marr suggested that this rigid block was formed in the main of Pre-Cambrian rocks with a fringe of Lower Palæozoic strata deposited against its flanks, the whole having been compacted in pre-Carboniferous times. In the Austwick-Horton area, therefore, we may expect to find evidence of successive transgressions with special marginal fades and signs of numerous breaks in the succession, which features are absent or not well defined in the more central parts of the Lower Palæozoic trough of the Lake District and southern Scotland. It is with the hope of throwing some light on these matters that we venture to add yet another to the long list of papers on this district of Yorkshire.

The mapping and collecting of material has been carried out by both authors. The detailed mapping was begun in 1920 by Mr. Wilcockson, and he also collected the greater part of the fossil material.

Professor King took the Cambridge field-mapping classes here from 1920 to 1931 inclusive, and during that time examined many of the exposures and determined certain fossil localities. Trenches were dug by Mr. Wilcockson in 1920 with the aid of grants from the British Association, and two trenches were dug
The Pre-Cambrian and Lower Palæozoic Rocks of the Eastern end of the St. David's Pre-Cambrian Area, Pembrokeshire
Authors: Williams Thomas George
Published: October 2009

I.Introduction

This paper describes the geological structure of a strip of country lying between four and 12 miles east of St. David's, and occupying the central portion of the small peninsula of north-western Pembrokeshire. Although in a district made classical by the researches of many famous geologists, this tract has received but passing notice, and, up to the present, has remained practically unknown geologically. The area is about 30 square miles in extent, measuring rather more than seven miles from east to west and four miles from north to south. It is bounded on the east by the G.W.R. main line to Fishguard, where the line runs along the Western Cleddau valley, between Welsh Hook and Mathry Road (Heathfield). On the north it adjoins the Abereiddy-Abercastle area (Cox, 1915, p. 273) and the Pen Caer area (Cox, 1930, p. 274), while to the south is the Brawdy-Hayscastle area (Thomas & Jones, 1912, p. 374). The St. David's area (Green, 1908, p. 363) and the Trefgarn area (Thomas & Cox, 1924, p. 520) lie respectively a few miles to the west and south-east.

The country here described is represented on the Ordnance Survey six-inch quarter-sheets, Pembrokeshire 15 N.E., S.E., N.W., S.W., 16 N.W., S.W., 8 S.E., and 9 S.W., and it comprises a portion of the area embraced by the Geological Survey one-inch maps, Sheet 40 (Old Series) and Sheet 209 (New Series).

The district forms part of the Pembrokeshire 400-foot peneplain, and shows the monotonous topography typical of the in
The Younger Intrusive Rocks of the Kudaru Hills, Nigeria
Authors: Bain Alexander David Neil
Published: October 2009

I. Introduction

A Preliminary account of the geology of the Kudaru Hills was published in 1927 (Bain), but a more detailed study of the group has since been completed and is now presented. The discovery of fayalite in certain rocks has necessitated a modification in the terminology and order of intrusion given in the first account.

The hills are in the Zaria Province of Nigeria, lying midway between the towns of Zaria and Jos on the railway (Fig. 1). The area is about 65 square miles and has an oval outline with the longer axis running north-east and south-west. The axes measure 11 miles and 7½ miles respectively. To the south, near Munchira, joined to the main mass of the hills by a low neck, is a prolongation of the main intrusion which rises to a considerable height in D. Nasalwa and which measures 2½ miles by 1 mile. Bordering the group on the north and east sides is a curved ridge containing some high peaks (Pl. VIII). Separating this ridge from the main part of the group is a crescent-shaped plain divided into two by a number of low hills west of Babinda village. This plain is underlain by various gneisses, while the rest of the district consists of later members of the Younger Intrusive series of the Northern Provinces of Nigeria (Falconer, 1923).

The highest peaks are in the interior but not in the centre of the group, and bare massive ridges of solid granite are there developed,
New Forms from the Insect Fauna of the British Coal Measures
Authors: Bolton Herbert
Published: October 2009

I. Introduction

The present paper contains the results of an examination of a suite of fossil insect wings discovered by Dr. Emily Dix, Prof. A. E. Trueman, Mr. W. Hemingway, and officers of the Geological Survey, to all of whom I would acknowledge my indebtedness for the generous loan of the specimens.

The work has been done by means of a Government Research grant from the Royal Society.

The specimens comprise about half the series discovered, the remainder including a number of wings whose structure has as yet defied analysis.

One species is referred to a family of the Palæodictyoptera, the most archaic group of fossil insects; two others are clearly palæodictyopteroid but, owing to their fragmentary character, cannot be assigned to any known group; three wings are referred to genera of the Protoblattoidea not previously recorded from Great Britain; whilst the list of Blattoidea from British Coal Measures is increased by two new species of the family Archimylacridæ and two species of Mylacridæ. Two forms are referred to the provisional order Hapalopteroidea, hitherto known only from the Anthracitic series of Sharp Mountain Gap, Vermont, Pennsylvania, U.S.A. Five specimens are indeterminable. Diagnosis.—wings twice as long as wide, and thin. Costal margin distally curved inward. Secondary branching abundant, and dividing by regular bifurcation. Diagnosis.—Wings thin, two to three times as long as wide, coastal margin curving inward into a small rounded apex. Inner margin almost straight. Veins branching by regular bifurcation. Diagnosis.— Wings at least two and a half times as
A Granite-Schist Contact in Stewart Island, New Zealand
Authors: Williams Gordon John
Published: October 2009

I. Introduction

Stewart Island is a rugged and almost uninhabited island lying off the southern coast of New Zealand. It is densely forested, but along the summits of the bleak wind-swept highlands, which are constantly buried in cloud, the thick bush gives way to scrub and tussock, and some bare rock-surfaces are exposed.

The granite peaks of Stewart Island expose sections of an extensive granite batholith, which makes up the greater part of the island and probably extends 60 miles south to the desolate Snares Islands and 70 miles north-west to the fiord country of the South Island of New Zealand. The granite invaded a biotite-muscovite-schist with interlaminated quartzite, a chloritized kyanite-amphibole-schist, and a calc-silicate-hornfels. All these rock types occur as small pendants in the granite (see map, Pl. XI), but the mica-schist predominates.

The object of the paper is to discuss the origin of the mica-schist, the manner in which it was dispersed to give place to magma, and the mineralogical changes produced in both the granite and the schist by reaction between these rocks and the fugitive constituents of the magma. Where relevant, passing mention will be made of the calcareous rocks.

The fugitive substances were reactive at two periods: (1) prior to the ascent of the main intrusion, when gases passed into the roof of the batholith and either contributed to the formation of the micas of the schist or were responsible for the persistence of the micas into the innermost aureole; and (2) subsequent to the
The Central and South-West Highland Epidiorites: A Study in Progressive Metamorphism
Authors: Wiseman John Dugdale Holt
Published: October 2009

I. Introduction

Ever since the publication of Teall's description of the Scourie dyke (1885, p. 133) and its passage from a dolerite into a foliated amphibolite by the ordinary processes of metamorphism, petrologists have from time to time directed their researches along modern lines to a study of the metamorphism of basic igneous rocks. No formal review of the literature is necessary owing to the numerous references contained in the following pages, but among the earlier writers Maculloch (1821, p. 298), De la Beche (1834, pp. 298
et seq.
) and Sterry Hunt (1875) may be mentioned. Although frequently the work of these authors was a model of careful observation and accurate description, their inference that hornblendic rocks were chemical precipitates from a thermal ocean can to-day be regarded as of historical interest only. It was thus left for Jukes (1862, pp. 169–72) to suggest that many hornblendic rocks were altered lavas or tuffs. Dealing with amphibblites chiefly from the south-west of England, Allport (1876, p. 422), Phillips(1876, p. 155,and 1878, p.471), and Bonney (1883, p. 14) expressed the opinion that they were metamorphosed igneous rocks. Shortly afterwards, the Scottish Geological Survey (Geikie, 1884, p. 122) in the course of their investigations on the amphibolites of Aberdeenshire and Banffshire came to a similar conclusion.

Lehmann (1884, p. 190) also arrived at this conclusion for the amphibolites from the Saxon Granulitgebirge, when describing the passage of a gabbro into a schistose amphibolite, whilst Lessen (1882–3) studied the contact metamorphism of a diabase
West Highland Tectonics: Loch Leven to Glen Roy
Authors: Bailey Edward Battersby
Published: October 2009

I. Introduction

The present paper is a sequel to my paper on the “Recumbent Folds in the Schists of the Scottish Highlands”, published in this journal in 1910, and expanded with certain corrections and discussions in a Geological Survey Memoir on the “Geology of Ben Nevis and Glen Coe”, 1916. The existence of these two publications allows of concentration on new features of interpretation.

The Loch Leven referred to in the title is the salt-water loch of that name, between Argyll and Inverness-shire. The coastal parts of the district are well served by roads, railways, and steamers. There are also inland roads through Glen Etive, Glen Coe, Glen Spean, and Glen Roy. The main villages or small towns are Ballachulish, Kinlochleven, Onich, Fort William, and Spean Bridge. Accommodation is easy to get.

The geological facilities include good exposures, high relief, and wonderfully definite lithology. Some of the mountains are carved out of Devonian igneous rocks, as at Ben Nevis and around Glen Coe, but much the greater number consist of the schistose rocks which concern us here. These peaks include a large number rising well above 3000 feet in height, and one, Aonach Beag, surpassing the 4000-foot level.

When I described the Ballachulish stratigraphical succession in 1910, and again in 1916,1 was careful not to suggest an original
order of superposition
. I described recumbent folds, but left it to the future to decide which set of limbs was normal and which inverted. In 1922, however, I attempted a comprehensive treatment
Downtonian Fossils from the Anglowelsh Area
Authors: Owper Reed F. B.
Published: October 2009

Shell transversely oval to subrhomboidal, nearly twice as long as wide; hinge-line straight, less than length of shell; beaks small, low, contiguous, directed forwards, situated at about one-third (or less than one-third) length of shell; anterior end projecting, rather sharply rounded; ventral margin gently arched; posterior end rounded below, subtruncate above, meeting hinge-line at obtuse angle. Valves moderately convex, without distinct umbonal ridge, but with small subtriangular somewhat flattened or gently concave posterior area; anterior third or two-fifths of surface smooth, except for concentric striæ; middle three-fifths or half ornamented with 5 to 7 radial ribs somewhat obliquely directed backwards, of which the anterior 2 or 3 are broad, flattened, subequal, and separated by narrow grooves less than half their width; the posterior 3 or 4 ribs are narrower, closely placed, and less flattened, occasionally with small scabrosities on them; posterior area smooth, except for concentric striæ. A few submarginal concentric lamellose growth-ridges are occasionally present, and a fine granulation is visible, with a lens, over the whole surface. Anterior muscle-scar small, oval. Dentition unknown.

Dimensions—Length 8–13 mm.; height 5–6 mm. Remarks.— This shell has been identified with
Pleurophorus virelyi
Barrois (Barrois & other, 1920, p. 145, pl. svi. fig. 10), of the Psammites de Liévin of l'Escarpelle, Liévin, but it seems to differ slighty in its more oval shape, in the greater number of radial ribs, and the fact that the last 3 or 4 are notably smaller than the anterior 3; the hinge-line also seems shorter and the
The Metamorphic Geology of Unst in the Shetland Islands
Authors: Read Herbert Harold
Published: October 2009

I. Introduction

The Shetland Islands occupy a critical position in the Caledonian mountain area. They lie about 200 miles north-east of the post-Cambrian dislocations of Durness in Sutherland, the same distance north of the Dalradian outcrops of the Banffshire coast, and the same distance west of the metamorphic region of Bergen in Norway. The investigation of their tectonics and metamorphism is required in any synthesis of the Caledonian front.

The island of Unst is the most northerly of the group. Its size is about 50 square miles. Its coastline reaches the great length of nearly 70 miles, and, though formed of cliffs usually hundreds of feet high, is for the most part readily accessible. Inland exposures are good, while even where peat partly obscures the solid rocks, as happens with some of the politic gneisses, outcrops are sufficient for the mapping of small divisions.

During the field-seasons of 1929 and 1930, I mapped the island on the scale of 6 inches to a mile while a member of H.M. Geological Survey. Since then the material has been worked out at the University of Liverpool. In 1933 I spent three weeks in the island in order to test certain points that had arisen during the laboratory study. I desire to express my thanks to Sir John Flett, Director of the Survey, for permission to complete the Unst work and to present this account.

Unst consists entirely of rocks that have undergone one or more metamorphisms under markedly different physical controls. The
The Rocks below the Red Chalk of Lincolnshire, and their Cephalopod Faunas
Authors: Swinnerton Henry Hurd
Published: October 2009

I. Introduction

Though the rocks below the Red Chalk of Lincolnshire are of peculiar interest, the absence of exposures along the coast, together with the rarity and transitory character of inland excavations, have made it exceedingly difficult to build up a body of information that approaches, even approximately, that standard of detail and accuracy which characterizes modern stratigraphy. Any information that can be culled from borings is, therefore, of especial value.

In the early summer of 1932 the Alford Town Council sank a boring in search of water from the Spilsby Sandstone. After piercing a thick covering of boulder-clay, the boring entered the lower part of the Red Chalk and then passed through 200 feet of other strata before entering the Spilsby Sandstone. Fortunately, a long spell of dry weather preserved the core from that rapid disintegration which would have been produced by rain, and also enabled me to make the requisite number of journeys from Nottingham to Alford for effecting a careful examination of the core. My heartiest thanks are due to Mr. R. Bentham and to Mr. P. E. Kent, who accom- panied me on most of the journeys and helped me with the laborious task of breaking up the rock and of making a thoroughly representative collection of specimens from all portions of the core.

Other borings have subsequently been put down at Maitbyle-Marsh, Fordington, and Skegness, but the use of the percussion method of boring, and other circumstances, have prevented me from obtaining more than fragmentary
Upper Devonian Goniatites from Mount Pierre, Kimberley District, Western Australia
Authors: Delépine Gaston
Published: October 2009

I. Introduction

In 1890, A. H. Foord described Palæozoic fossils from the Kimberley District, Western Australia. Amongst them were Devonian brachiopods and fragments of indeterminable goniatites.

In 1924, A. Wade collected many goniatites at Mount Pierre. He figured seven specimens in his report (1924, pl. iii). The description of this plate, by Chapman (1925?), records: “Various Cephalopod shells, including ammonitoid forms as
Aganides
and (?)
Gonioclymenia
, and a cyrtoceracone (Nautiloid shell). Devonian or Carboniferous.’ A number of the goniatites collected by Wade are preserved in the British Museum (Natural History), where they are registered under the numbers C.35270 to C.35365; they do not, however, include the figured examples.

Recently, Professor E. de C. Clarke sent some goniatites to me from the same district, with the following note:—

‘The specimens occur in a red limestone at Mount Pierre, on the Margaret River. At the same locality a white limestone occurs which is considered Devonian and contains
Atrypa aspera, desquamata, Wilsonia cuboides
and
Pugnax pugnus
. At present nothing is known of the relationship of the red limestone to the white
Atrypa
-limestone.’

I am indebted to Dr. W. D. Lang and Dr. L. F. Spath for enabling me to study specimens in their charge at the British Museum (Natural History).

Sixteen specimens of this species have been collected by Professor Clarke at Mount Pierre. The Wade collection contains many more specimens, 84 of them being in the British Museum (Natural History). Many of these goniatites, as, for example, the four specimens figured here,
The Westleton Series of East Anglia: its Age, Distribution, and Relations
Authors: Solomon John David
Published: October 2009

I. Introduction

On the Geological Survey maps of the country to the south-east of the Chalk escarpment, numerous areas, extending almost continuously from Norfolk to Berkshire, are shown coloured in various shades of pink and described somewhat non-committally as “Glacial Sand”. It is clear that several deposits of various origins have been included under this heading, but as yet no intensive attempt has been made to distinguish between them over more than a very limited area. The task is, indeed, in the absence of fossils, a matter of great difficulty. Some workers have drawn criteria from the pebble content of the gravels, but these criteria have sometimes led them astray, and in any case are not applicable to the sandy deposits.

My own method has been to make use of the heavy mineral assemblages, which are obviously of great value in investigating the “directional” deposits formed from ice-borne material, and which are applicable equally to sands and gravels. The results obtained are in partial agreement with those of many previous workers, notably Prestwich, S. V. Wood, H. B. Woodward, A. E. Salter, and R. L. Sherlock. The fresh evidence obtained during the present investigation helps also to resolve many of the mutual contradictions inherent in their conclusions.

II. Historical Summary

It would be useless and tedious to attempt a summary of all the older work on the subject; I have therefore limited myself to the important publications, and especially to those which express the latest views of their authors.

Searles
On a New Section of Fossiliferous Upper Cornbrash of North-Eastern Facies at Enslow Bridge, near Oxford
Authors: Douglas James Archibald , Arkell William Joscelyn
Published: October 2009

In a recent account of the stratigraphical distribution of the English Cornbrash we pointed out that positive evidence of the existence of Upper Cornbrash was lacking over an extensive area of outcrop north and east of Oxford. All that we were then able to say (1932, p. 123) was: “Over this area the Lower Cornbrash alone forms a surface feature or appears in any of the exposures. The thin representative of the Upper Cornbrash, seen in the Long Handborough and Kidlington quarries and during the construction of the Woodstock railway, if it is present to the north-east of Oxford, has nowhere been encountered nearer than Bedford, 50 miles distant.” We had previously stated, however, in an analysis of the fauna of the South-Western area, including the Oxford district: “The record is still far from complete; new exposures in the area will furnish additional facts.”

Such an exposure has now come into existence, and the Upper Cornbrash thereby revealed, although but a thin formation, has proved so richly fossiliferous, and the light thrown on questions previously doubtful is so illuminating, that we consider a description of the section should be made known without delay.

The quarries at Greenhill, near Enslow Bridge on the River Cherwell, about nine miles north of Oxford, have been famous since the days of Buckland as a hunting ground for Cornbrash fossils; but although they have been visited by many generations of collectors, no fossils indicative of the Upper Cornbrash have hitherto been recorded. When describing the
The Composite Gneiss and Contaminated Granodiorite of Glen Shee, Perthshire
Authors: Williamson William Owen
Published: October 2009

The area discussed is depicted on Sheet 56 of the 1-inch map of the Geological Survey of Scotland. This sheet was geologically surveyed by James Geikie, H. M. Skae, and G. Barrow, and is not accompanied by a Memoir.

The district shown in Fig. 1 has received the scantiest notice in geological literature. Fundamentally, its rocks are metamorphosed sediments of the Dalradian Series, invaded by intrusions of various characters and ages. Their apparent sequence, as set forth on Sheet 56 and by Bailey (1925, p. 673, and map opposite p. 698), is as follows:—

This table may show the true or the inverted succession (Bailey, 1925, p. 672, footnote). Bailey's terminology is here adopted.

“Basic Older Igneous Rocks” are intercalated with both Ben Lui and Ben Lawers sediments of Glen Shee. Further, the region includes a mass of “Older Granite” which, by invasion of the Ben Lui Schist, produced a complex termed the “Duchray Hill Gneiss”. Sheet 56 shows the gneiss as a band, which is continued on the adjoining Sheets Nos. 55 and 65 (cf. Read, 1928, map on p. 768). In the Memoirs on Sheets 55 and 65 the gneiss is briefly described and reference made to the type area of Duchray Hill (Barrow, 1905, pp. 101–2; 1912, pp. 69–70). Bailey (1925, p. 676) has verified the igneous nature of much of the material exposed on this hill.

Read (1927, pp. 337–8) has compared the composite oligoclase-biotite-gneisses of Cromar, in their respect to their origin, with the Duchray
The Basic Intrusive Rocks Associated with the Cambrian Inlier Near Malvern
Authors: Blyth Francis George Henry
Published: October 2009

I. Introduction

T
he
rocks to be described occur as minor intrusions in the Cambrian strata which are exposed in a small elongated inlier situated on the western flank of the Malvern Hills, east of Eastnor village, Herefordshire (Ordnance Survey 6-inch sheet, Hereford XLII NW.). Their general petrographic features have been described by T. T. Groom (1899, pl. xiii; 1901, p. 158), whose work is now supplemented by the results of a chemical and petrological re-examination of the rocks. Groom (loc. cit.) showed that the intrusives invade the Cambrian strata but not the Silurian. He recognized three main types: (1) an amphibole-bearing andesitic type (probably camptonitic), forming dykes, sills, and bosses; (2) porphyritic olivine-basalts, forming sills and small laccolites, and (3) olivine-diabases, forming sills with porphyritic margins. These were found at five localities only in the grey Bronsil Shales.

Further descriptive reference to these rocks is confined to one instance, by Groom himself (1910, p. 704).

II. Petrography

With some modification of nomenclature the abovementioned three-fold grouping is retained in the following description of the main rock-types.

The Splitic Andesities (Group A)

These are very fine-grained purplish grey rocks, porphyritic and sometimes trachytic in texture, corresponding in general with Groom's “amphibole-bearing andesitic type”. They are free from vesicles, and occur as (1) dykes in the Hollybush Sandstone north-north-west of Ragged Stone Hill, and (2) bosses or sills in the black shales south-east of Fowlet Farm, and the grey shales south-east of Martins (Fig. 1).

In thin section they show a microcrystalline
The Gastropoda and Lamellibranchia of the Green Ammonite Beds of Dorset
Authors: Cox Leslie Reginald
Published: October 2009

I. Introduction.

Most of the mollusca here described have been collected during the past 30 years by Dr. W. D. Lang. Older material in the British Museum collection shows that the Green Ammonite Beds had also occupied the attention of such collectors as the Rev. P. B. Brodie, R. F. Tomes, and (especially) T. J. Slatter, but the exact horizons of their specimens are unrecorded. Of previous published records of non-cephalopod mollusca from these beds, reference need only be made to R. Tate's description (1870
a
, p. 404) of four small gastropod species,
Straparolus wrightianus, S. bellulus, S. aratus
, and
Littorina biornata
, obtained by H. B. Brady in washing material collected by T. Wright for foramintfera, and to a short list published by E. C. H. Day (1863, p. 291), which includes the two forms
Chemnitzia carrucensis
[
sic
] d'Orbigny and
Pterocera liasina
d'Orbigny. The first of Day's records (
Chemnitzia carusensis
d'Orbigny) may or may not be correct; the species is not in the material examined by me. His record of
P. liasina
is meaningless, as this form has been ignored by French authors since its original, and totally inadequate, description in d'Orbigny's
Prodrome
, and the type is no longer extant.
1

The most notable feature of the non-cephalopod molluscan fauna of these beds is the abundance of small gastropods, particularly a few feet above the Belemnite Stone, and of Taxodont lamellibranchs belonging to the genera
Nucula, Nuculana
, and
Parallelodon
.

Most of the lamellibranchs and some of the gastropods are long-ranging forms. A
Brachiopoda from the Lower Lias, Green Ammonite Beds, of Dorset
Authors: Muir-Wood Helen M.
Published: October 2009

I. Introduction.

Brachiopods are rare in the Green Ammonite Beds of Dorset and are represented by only three species, two of which belong to the Discinidæ and one to the Rhynchonellidæ. The specimens, with one exception, are of small size and are usually much crushed and distorted.

The most abundant species is
Scalpellirhynchia scalpellum
(Quenstedt), which is found mainly in beds 129 and 130, just below the Middle Lias, while a few scattered specimens occur below in beds 122–126 and 127. This species occurs in the lower part of the Lias δ of Württemberg, but has not been previously recorded from this country, owing probably to the lack of careful collecting in other areas of Liassic deposits.

An investigation of the internal structure of
S. scalpellum
was made by grinding transverse and longitudinal sections of specimens that had been previously heated to redness and embedded in plaster cubes when cool. A full description of this method is given elsewhere (Muir-Wood, 1934).

One pedicle valve of a
Discinisca
of exceptionally large size was obtained from bed 130. One small specimen of
Discinisca holdeni
was obtained from the Upper Limestone, bed 129a, and a second specimen from the Red Band, bed 126a of Stonebarrow Cliff.

All the material was collected by Dr. W. D. Lang and is preserved in the British Museum of Natural History collection.

The specimen [B52300] consists of the conical valve only, of which all but the innermost layer of the shell is missing. The shape is approximately circular
A Further Contribution on the Karroo Rocks of Tanganyika Territory
Authors: Stockley Gordon Murray
Published: October 2009

The occurrence of Karroo rocks in Tanganyika has been known virtually from the time of Livingstone, who is reported to have discovered coal in the Upper Rovuma. The best known occurrence is that south of Manda, near Lake Nyasa, which is described by Bornhardt. To people within the Territory, however, the Ufipa coalfield in the Kigoma Province is the most familiar. The following list of outcrops of definitely known Karroo rocks is given in order of economic importance.

1.

Ruhuhu coalfields, Njombe and Songea Districts.

2.

Kivira-Songwe coalfields, Tukuyu District.

3.

Ufipa coalfield, Ufipa District.

4.

Kidodi area, South Kilosa District.

5.

Rufiji-Ngerengere area, Morogoro and Rufiji Districts.

6.

Tanga.

7.

Mitomoni on the Portuguese border, on the Rovuma, south of Songea.

Other areas where rocks occur which are now considered to be of Karroo age, though the evidence of fossils is wanting, are

8.

Uha area, in Kigoma District.

9.

Kingongolero Hill, south of Manyoni.

10.

The Rufiji-Luwegu area in the Mahenge and Liwale Districts.

The last-named is an area which may possibly be extended, and may finally link up with the Ruhuhu coalfields in the Songea District in the south; in the north, it passes into the Rufiji-Ngerengere and Tanga districts, and is partly overlain by marine Jurassic rocks north of the Central Railway. It is thus a region which may extend for nearly 500 miles, from Lake Nyasa to Moa, north of Tanga, and in which Karroo rocks are actually exposed for 350 miles. The Karroo formation
Karroo Lamellibranchia from Tanganyika Territory and Madagascar
Authors: Cox Leslie Reginald
Published: October 2009

This paper deals primarily with a large collection of lamellibranchia obtained by Mr. G. M. Stockley in 1931 from the Karroo beds of the Kidodi district of Tanganyika Territory. These fossils are of considerable interest as affording the first evidence of an Upper Permian marine incursion into an African Karroo basin of deposition, and also include numerous non-marine species new to the Karroo fauna.

It would have been impossible to determine the age of the marine fossils with any degree of certainty had it not been for the fortunate coincidence that, while studying them, I was shown a collection, including two of the same species, obtained from a known horizon in Madagascar by Mlle E. Basse. I must express my very warm thanks to her for relinquishing her original intention of describing her material herself and kindly permitting me to figure some of her specimens in the present paper.

The following details of the succession in the Kidodi district indicate the horizons of the fossils collected by Mr. Stockley:— Ruhembe Beds (3700 foot).— Sanstones and carbonaceous shales, including two molluscan horizons, the upper marine and the lower freshwater, separated by 1200 feet of massive sandstone. The lower horizon is 250 feet from the base of this series. Calcareous Beds (700–800 feet).—Carbonaceous shales, silicified limestones and calcareous sandstones, including an horizon with non-marine mollusca (mainly
Kidodia
, gen. nov.) about 415 feet from the top. Ndeke Beds (2900 feet).—Sandstones and conglomerates with intercalated mudstones, etc. Unfossiliferous. The rocks belonging to the upper
Gravity Collapse Structures and Mountain Ranges, as exemplified in South-Western Iran
Authors: Harrison John Vernon , Falcon Norman Leslie
Published: October 2009

The object of the present paper is to recapitulate our previous work on gravity-formed anomalous structures, to describe further examples, and to propound arguments based upon structures in the Swiss Alps and upon theoretical considerations.

In south-western Iran, post-Miocene orogenesis produced a series of approximately symmetrical folds, in section nearly sine curves, trending north-west and south-east. Vigorous erosion followed, revealing the following column of strata:—

The limestones now often protrude as strike ridges and dome-like ranges with the marl groups weathered away between and around them. Dissection, measured from the mountain summits to the strike stream beds, reaches as much as 8000 feet; earlier in the cycle it probably reached 12,000 feet.

When erosion left a knife edge upstanding or a dome unsheathed, the beds at first remained unaffected, but when the pile exceeded about 2000 feet in height they tended to bend and break, and to produce such secondary structures as
roof-and-wall, cascade, flap
, or
slip-sheet
. In every case, an unmoved control bed can be seen within the original fold; the form which these secondary structures took depended upon the attitude of the rock under the progressive denudation of its cover and support.

A
roof-and-wall
structure is produced from a sine-curve fold when the crest is notched by erosion, and the two sheets so produced slip down and outwards, bending at first into a knee-fold. This knee then breaks; the lower limb remains nearly vertical whilst the upper rests upon it with a sudden change in dip, and separated
The Differentiated Dyke of Newmains, Dumfriesshire, and its Contact and Contamination Phenomena
Authors: Kennedy William Quarrier , Read Herbert Harold
Published: October 2009

I. Introduction

Within the Southern Uplands of Scotland, the highly folded Ordovician and Silurian sediments are intruded by a suite of calc-alkaline igneous rocks of Lower Old Red Sandstone age which includes a well-developed dyke swarm. The dykes trend in a north-east and south-west direction and, although individually thin, collectively they represent a considerable body of magma.

The only literature dealing with the subject, however, is Teall's generalized account in the Southern Upland Memoir (1899, pp. 625–31), a paper by Read (1926) on the micalamprophyres of Wigtownshire, and a short section in the description by Gardiner and Reynolds of the Loch Doon granite (1932, pp. 19–26).

The Newmains dyke, which forms the subject of the present paper, is a member of the Southern Upland swarm and crops out on the hillside immediately north and north-east of Newmains farm, some 4½ miles west of Dumfries and within Sheet 9 of the 1-inch Geological Survey Map (Fig. 1). The dyke is about 15 feet wide and runs for a little more than a mile in a general north-east and south-west direction, in conformity with the strike of the Silurian (Llandovery-Tarannon) greywackes into which it is intruded. It is a typically heterogeneous, differentiated intrusion and consists of three main rock types associated in an intimate manner. The main rock is a granophyric spessartite or markfieldite, which passes on the one hand into a basic, hornblende-rich type and on the other into a leucocratic variety poor in ferromagnesian constituents. These three rock types are
The Ammonite Zones of the Upper Oxfordian of Oxford, and the Horizons of the Sowerbys' and Buckman's Types
Authors: Arkell William Joscelyn
Published: October 2009

It is more than a century since J. and J. de C. Sowerby figured in
The Mineral Conchology
, from the Corallian of the neighbourhood of Oxford, the type specimens of
Ammonites plicatilis, Am. cordatus, Am. excavatus, Am. vertebralis
and
Am. catena
, and since Brongniart made the district the type and standard of the Oxfordian stage, a term adopted by Marcou and, after emendation by d'Orbigny, eventually disseminated in the stratigraphical literature of the whole world.

Nevertheless, in spite of the time that has elapsed and of the labours of S. S. Buckman in the district, the precise stratigraphical horizons and ranges of the Sowerbyan types remain obscure, as does also the whole succession of ammonite faunas. This obscurity is reflected in the variety of interpretations that have been put upon the term “Oxfordian stage” (see Arkell, 1927, pp. 154–5). I accept here the scope of the stage as stabilized by d'Orbigny (1852, p. 522: “l'Oxford Clay, le Calcareous Grit, le Coralline Oolite de M. Phillips” [the last the Oxford Oolite of Buckland and Fitton]) in which form (including, of course, the coral rags) it has also been accepted by Dr. Spath in his latest comprehensive table of Jurassic stages (1933, p. 872). The Upper Oxfordian as there represented, and as now commonly understood, corresponds with the Corallian beds in England and the Argovian and Rauracian substages on the Continent.

In this paper I attempt to show the content of the Upper Oxfordian, with special referrence to ammonite horizons, in the
The Age of the Sarn Granite
Authors: Matley Charles Alfred , Smith Bernard
Published: October 2009

The age of the granitic and gneissose rocks near Sarn, Rhôs Hirwaen, and Meillionydd in south-western Lleyn has long been a subject of difference of geological opinion. The granite and its gneissic associates were originally mapped together by the Geological Survey as “syenite”, and were generally known as the “Rhôs Hirwaen syenite”; this was considered by Ramsay to be of Palæozoic age. Later, Hicks visited Lleyn, and among the numerous rocks in that district which, in 1878, he claimed to be of Pre-Cambrian age was the Rhôs Hirwaen “syenite”, which he called a metamorphic Dimetian granitoidite. Tawney soon afterwards examined the geological relationships of the rocks mentioned by Hicks and came to the conclusion that “of all the areas of rock in the Lleyn promontory which Dr. Hicks claims as Pre-Cambrian, this patch of metamorphic rocks near Sarn [that is, the Rhôs Hirwaen “syenite”] seems to be the only one with any claim. It is, however, unfortunate that we have not been able to find any fragments of it inclosed in Cambrian beds” (1883, p. 68).

Tawney's opinion was based on the examination of the junction of the granite and Ordovician sediments in a quarry near a fine cromlech at the north-eastern margin of the granite mass, which he calls “the quarry by Amwlch Lodge”. As the cottage is now shown on the six-inch map as “Mountain Cottage” the exposure will be referred to in future as “Mountain Cottage Quarry” (Fig. 1). Tawney's account shows that he had considerable difficulty
Observations on the Distribution of Land and Freshwater Mollusca in the Southern Libyan Desert
Authors: Sandford Kenneth Stuart
Published: October 2009

In the course of a reconnaissance of the southern Libyan Desert and north-western frontiers of the Anglo-Egyptian Sudan, led by Major R. A. Bagnold (1933), I searched carefully for shells in oases and other localities. Of species now living in other parts of Africa, some were found only in the geological deposits of some oases, while a few appear to be living in this region in certain circumstances. Thus, shells of a land-snail common in tropical Africa were found in regions now totally arid, and the molluscs had evidently lived and multiplied there recently. Moreover, the freshwater species found in widely separated localities can breed only near or in water, and their dispersal or survival is an interesting problem.

Evidence will be given to show that small and purely temporary changes of precipitation—a matter of good or bad rain years—have disproportionate results in arid lands. Rapid re-colonization by molluscs follows exceptional rains, and in some instances a few individuals have survived long droughts. An explanation is offered in this paper of the alternations of barren and highly fossiliferous continental deposits found in this and other arid regions. Deductions as to climatic changes, made from the evidence of such alternations of superficial deposits in lands now or previously arid, are unsafe, and may give rise to confusion or doubtful correlations.

This paper, written in 1934, was intended to be a study of the past and present conditions of the southern part of the Libyan Desert, and to demonstrate some of the