bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Geology of Snowdon, North Wales
Authors: Williams Howel 
Published: October 2009

I. Introduction.
The area to be described is limited on the north-east by the Pass of Llanberis from near the village of Nant Peris to Pen-y-gwrhyd; on the south-east by the Vale of Gwynant down to Beddgelert; on the south-west by the Colwyn and Gwyrfai valleys to near the village of Salem; and on the north-west by the supposed line of junction between the Cambrian and the Ordovician rocks. The approximately quadrilateral area of Ordovician rocks thus defined has an extent of about 30 square miles. It is represented on portions of the 1-inch Ordnance Survey maps 106 & 119, of the 6-inch sheet, Caernarvonshire 22, and of the Quarter-sheets 16 S.E., 17 S.W., 21 N.E. & S.E., 27 N.E., & 28 N.W. It includes parts of the Quarter-sheets 75 N.E. & 78 S.E. of the 1-inch Geological Survey map (old series).
The general configuration of Snowdon is represented on the map, PL. XXIX. Prof. W. M. Davis's paper on ‘Glacial Erosion in North Wales’ [42] affords a useful guide to the topography, and is considered adequate for the present purpose.
(a) Historical Review.
On his first visit to North Wales in 1831, Sedgwick drew a section through Snowdon, in which he depicted the synclinal structure of the summit and the descending sequence of beds towards the north-west. From this section and from others across Y Glyder Fawr and Moel Hebog, he ascertained the general parallelism of the fold-axes in this part of Caernarvonshire. Subsequently, he determined the general succession
On some Mammalian Remains from Lake Nyasa
Authors: Hopwood Arthur Tindell 
Published: October 2009

Though the kindness of Dr. F. Dixey I have been privileged to examine a number of fragments brought back by him from the Chiwondo Beds of Uraha Hill, Lake Nyasa. They are very much broken up, and only three pieces are in sufficiently good condition to allow of a generic name being applied to them. Nevertheless, they are of great interest, since they are the first vertebrate remains to be obtained from that region, and since they indicate a fresh means of throwing light on the problems connected with the Great Rift-Valley.
The bones are highly mineralized, of a greyish colour, and are badly cracked and fissured. Some at least of the cracking was effected before burial, but much of it is due to subsequent weathering. The matrix is a coarse quartzose grit with a calcareous cement. It is very hard, with numerous pockets of soft unconsolidated matter. in this respect it resembles the deposits of the Albert Nyanza and of the Victoria Nyanza. The Albert Nyanza deposits are cemented by oxides of iron, and are dark brown or black; but the fossils collected by Dr. Felix Oswald in the neighbourhood of Lake Victoria are, so far as the state of preservation is concerned, hardly to be distinguished from those collected by Dr. Dixey.
This does not prove that the beds near Lakes Nyasa and Victoria are of the same age. It is most unwise to rely on lithology as a means of correlation, especially when dealing with lacustrine deposits.
A Critical Revision of the Rugose Corals described by W. Lonsdale in Murchison's ‘Silurian System’
Authors: Lang William Dickson , Smith Stanley 
Published: October 2009

W. Lonsdale, in R. I. Murchison's ‘Silurian System’, 1839, pp. 675–94, pis. xv, xv
bis
, xvi, & xvi
bis
, described and figured a number of Silurian corals and polyzoa. In view of the prominence of this work in the literature of Palæozoic corals and polyzoa, and the importance to nomenclature of a right interpretation of many of Lonsdale's figured forms, it is desirable that whenever possible the types and figured specimens should be re-examined and their internal structure carefully investigated.

It should be noted that our paper deals solely with the Rugose corals. The genotypes of several genera are involved, as well as the types of a number of species. Many of Lonsdale's forms have been misinterpreted by later authors, and placed by them in the synonymies of totally different coral-species.
Our paper has issued as a by-product of a work of wider scope begun in 1923—namely, an investigation of all the genera to which Palæozoic corals have been referred, with a view to determining their genotypes; it is also auxiliary to our impending publication dealing with the Silurian corals described in Linnæus's ‘Corallia Baltica’ and with the genera and species involved in a consideration of these. It aims at identifying unmistakably Lonsdale's Rugose coral-species, describing in detail those which do not come within the scope of our other work, and only very briefly considering such as will be fully described in that work. It has, however, been found desirable to consider also several of McCoy's types, as well as
The Geology of the Country between Llanelidan and Bryneglwys
Authors: Blackie Robert Churchill 
Published: October 2009

The district here described lies partly in southern Denbighshire and partly in north-eastern Merionethshire. It covers an area of about twenty square miles, and includes the upper part of the Vale of Clwyd, and the upland region on the south of it. The parishes of Derwen, Grwyddelwern, Llanelidan, a large part of Bryneglwys and part of Llansantfraid-Grlyn-Dyfrdwy are included in the area. A close geological and geographical relationship exists between the present district and the main mass of the Denbighshire Moors on the north-west. The region consists of a more or less flat-topped upland which has been dissected by numerous valleys. The average height of the land is 1000 feet, but to north, west, and south it descends below 600 feet O.D.
Towards the east the area is connected by a ridge extending from Moel Traan to Mynydd-Cricor, averaging 1000 feet in height. The district here described thus forms a more or less rectangular tract of relatively high land surrounded on three sides by low-lying valleys.
The grain of the country runs from south-west to north-east, and is thus of Caledonian trend. A system of parallel valleys, most of which carry streams, separates the ridges. Less well-marked valleys also cut the upland in a west to east direction, intersecting the former at angles of about 60°. Where the two valley-systems meet, rather flat and swampy ground is usual.
On the north the uplands descend steeply to the upper part of the Vale of the Clwyd. The river Clywd follows this
The Old Red Sandstone of the Bristol District
Authors: Wallis Frederick Stretton 
Published: October 2009

The object of this investigation was to study the Old Red Sandstone of the Bristol district from the stratigraphical, palæontological, and petrographical aspects, with the view of elucidating the source of the sediments, their mode of transportation, and the conditions of deposition.
To this end, a British Association Research Committee was appointed at the Edinburgh (1921) meeting. To Dr. H. Bolton, Chairman of this Committee, I am indebted for the suggestion of this research and for the opportunity of carrying it out under the auspices of the Bristol Museum.
Interim reports were presented at the Annual Meetings of the Association from 1922 to 1925, and the final report was submitted in 1926.

The areas of Old Red Sandstone involved in the folded and faulted ‘Bristol Uplift’ were taken as the limits of the investigation (map, p. 762). They comprise:—

a.

Outcrops within the ridge of Avonian rocks stretching from Penpole Point through Westbury to Durdham Down.

b.

The area stretching from the River Avon (left bank) to the neighbourhood of Clapton-in-Gordano.

c.

A coastal ridge between Portishead and Clevedon.

wing to the almost complete absence of organic remains, the Old Red Sandstone has received little attention from local geologists, and records of sections are framed in very general terms.
In 1846 D. Williams gave a detailed account of the Old Red Sandstone sequence on the right bank of the Avon Gorge as it was then visible some twenty years before
Tertiary Foraminifera from the Naparima Region of Trinidad (British West Indies)
Authors: Nuttall Winfred Laurence Falkiner 
Published: October 2009

This paper presents the results of an examination of a large collection of Miocene and Upper Eocene Foraminifera from the Naparima region of Trinidad (British West Indies). The material was assembled by Prof. V. C. Illing, who is describing the stratigraphical and structural geology in a separate paper (1927, GN). One hundred and forty-four species of Foraminifera have been identified, and certain forms have been found to be of value in determining stratigraphical horizons.
I am indebted to Mr. C. Forster Cooper for giving me access to the Brady Collection of Foraminifera at Cambridge. Mr. R. Kirkpatrick kindly gave me facilities to examine that portion of the Brady Collection which is preserved in the Zoological Department of the British Museum (Natural History). Dr. W. D. Lang lent a small collection of specimens from the Trinidad Tertiary strata named by R. J. L. Guppy, who had placed them in the Geological Department of the British Museum (Natural History). Mr. E. Heron-Allen has kindly given advice regarding the identification of a few rare forms. I have studied a sample of Orbitoidal rock from Mount Moriah (Trinidad) collected by Mr. I. A.Stigand, and deposited in the Sedgwick Museum, Cambridge. The type-specimens and other material have been placed in the Sedgwick Museum, Cambridge.
Since the date of completion of the manuscript of this paper, Dr. J. A. Cushman has introduced a re visionary classification of the Foraminifera; also, several important papers on American Tertiary Foraminifera have appeared. It is regretted that no reference is
The Lower Carboniferous Rocks of the Menaian Region of Carnarvonshire: their Petrology, Succession, and Physiography
Authors: Greenly Edward 
Published: October 2009

The ancient name ‘Arvon’ compounded of ‘Ar’ = ‘opposite to’ and ‘Von’ = ‘Mon’ = ‘Anglesey’, may be adopted as a concise designation for the country which, extending from the vicinity of Aber to the western coast a few miles beyond Carnarvon, lies between the Menai Strait and the mountain-land. For some eight years past I have been surveying this country, and hope to present the results from time to time.
As its Upper Palæozoic rocks have now been completely surveyed, and as fossils amply sufficient to establish the zonal divisions have been obtained, their lower division can with convenience form the first instalment of ‘the Geology of Arvon.’

Without the contribution of Dr. Stanley Smith, this paper could not have been written at all, for he has undertaken the palæontology in general, besides the determination of the corals, which is entirely by him, and he spent several days with me on the ground. He is also responsible for part of the Limestone petrology, and procured the analysis of the ooliths made by Mr. T. W. Harrison. The numerous
Producti
were all named by Miss Helen Muir-Wood, while Mr. John Walton determined the plants. Certain fishes were named by Sir Arthur Smith Wood-ward, the ostracoda by Mr. T. H. Withers, while Mr. J. Wilfrid Jackson examined other forms and lent some fossils for comparison. Prof. P. G. H. Boswell has examined the heavy minerals of several of the formations, and Mr. H. C. Sargent has seen the cherts both in
The Pre-Cambrian Complex and Associated Rocks of South-Western Lleyn (Carnarvonshire). With a chapter on the Petrology of the Complex by Edward Greenly
Authors: Matley Charles Alfred , Greenly Edward 
Published: October 2009

The district with which this paper is concerned is the oblong coastal strip of the Lleyn peninsula of Carnarvonshire, about 14 miles long and 1 to 3 wide, that extends from Nevin in a south-westerly direction to Bardsey Sound and Aberdaron Bay. The coast-line forms a natural boundary on the north, west, and south, and the eastern boundary runs inland from the northern coast near Nevin to the southern coast on the east side of Aberdaron Bay, along an important line of dislocation (called in this paper the Boundary-Thrust) which separates the Pre-Cambrian country on the west from the Palæozoic region farther east. This latter region will form the subject of a separate communication, but lying within the Pre-Cambrian tract is an area of Palæozoic rocks around the village of Aberdaron which it will be more convenient to include in the present paper.
The study of the solid geology is rendered difficult by the thick mantle of Glacial drift, consisting of boulder-clays, sands, silts, and gravels, which have filled up the old drainage-basins to a great height and the ancient bays to a depth below present sea-level, as, for instance, at Forth Nevin and Porth Dinllaen on the north and Aberdaron Bay on the south. The present drainage is carried by little streams which for the greater part wander through the drift, but occasionally cut into the Pre-Glacial rock-floor. The sea-cliffs of drift often reach from sea-level to a height of 100 feet or more; but, fortunately for geological investigation,
The Geology of Part of North-Western Rhodesia
Authors: Murray-Hughes Robert 
Published: October 2009

I. I
ntroduction
.

The literature with special reference to Northern Rhodesia is not abundant. A. J. C. Molyneux made several visits to the country, but, although he must have collected a good deal of general information, he published only the results of his work on the distribution of the Karroo System in Northern Rhodesia (15). His work was confined to the stretch of country bounded on the north by the Kafue and Zambezi Rivers, on the west by the railway-line, and on the south and east by the boundary of Southern Rhodesia.
The outstanding piece of work was that of F. E. Studt (22). I suppose that only one who knew the country at about the same time as that during which Studt's mapping was done, can really appreciate the immensity of the task which he set himself. He certainly had Cornet's and others' investigations to aid him in his preliminary work in the Congo, but none for Northern Rhodesia.
Unfortunately for me, Studt's paper did not fall into my hands for several years after my interest in the geology of Northern Rhodesia had been quickened; neither did I have access to the publications relative to the Belgian Congo. So, for a long time, I traversed a road already surveyed. The greater part of the work was done in my own time during snatched shooting expeditions. In 1925 a year's field work was begun for the Rhodesia Minerals Concession Limited, and a good deal of the topography shown east of the
The Pliocene and Pleistocene Deposits of Wadi Qena and of the Nile Valley between Luxor and Assiut (QAU)
Authors: Sandford Kenneth Stuart 
Published: October 2009

I. I
ntroduction
.

In §§ V, VI, & VII the following plan is adopted:—Wadi Qena, being well adapted to the purpose, is taken as a type-area in which to explain general principles; the region between Luxor and Qena is used for a like purpose.
A rapid survey is then carried northwards along both sides of the Nile, the principles being taken for granted, and only new features emphasized and their bearing upon the general condition explained. Economy of space is thus effected.
For bibliography such references are given as will deal with the question in hand, and will lead to the full literature; no attempt is made to give a complete bibliography within the paper itself.
In the summer of 1925 Sir Flinders Petrie, F.R.S., on behalf of the British School of Archæology in Egypt, invited me to investigate certain problems which required purely geological training. These had already been set forth in print.
I went to Egypt in November of that year, and spent the winter months with a small camel-caravan on a march of some 600 miles (excluding offsets); the route is shown in Pl. XXVI.
The results, so far as the particular task was concerned, have been published in part, together with certain geographical, archæological, and other data. In the course of the work, however, allied problems of more general importance presented themselves, and provided the solution of the original object of research. I propose now to present and discuss the geological results of the survey. Between Assiut
The Glaciation of Eastern Edenside, the Alston Block, and the Carlisle Plain
Authors: Trotter Frederick Murray 
Published: October 2009

I. I
ntroduction
.

The glaciation of the area herein described first interested me while re-surveying the Longtown Sheet of the Geological Survey Map (N.S. Sheet 11) and the northern part of the Carlisle Sheet (N.S. Sheet 17). In this area there was evidence of two glaciations, and the later of these appeared to have emanated from the Southern Uplands of Scotland. The retreat of this ice-sheet was followed westwards along the northern shores of the Solway Firth in my vacation during the years 1921–22.
During the year 1923, the first year of the re-survey of the Brampton Sheet (1-inch N.S. 18) by the Geological Survey, a wealth of glacial retreat-phenomena of the earlier glaciation was discovered near Brampton, and briefly described in the Summary of Progress for that year. The evidence for a westward retreating ice-sheet was incontestable, but the direction of the drainage of the impounded glacier-lakes suggested the operation of Lake District rather than Galloway or Southern Upland Ice. The composition of the drift also threw grave doubts upon the accepted Scottish origin of this ice-sheet. Nevertheless, there were some puzzling features connected with the distribution of the erratics and the drift. To cite but one example: although Lake District erratics, principally lavas and ashes of the Borrowdale Volcanic Series, predominated in the drift, suggesting Lake District ice moving down Edenside, yet the drift did not contain a single boulder of Shap granite, a boulder to be expected from such an ice-movement. Therefore, before I committed myself to a
Foliation and its Relations to Folding in the Mona Complex at Rhoscolyn (Anglesey)
Authors: Greenly Edward 
Published: October 2009

In ‘The Geology of Anglesey’ it was pointed out that little had really been ascertained concerning the laws and chronology of the foliation of the Mona Complex. A chronology was given, but the foliation of Holy Isle was therein treated as a unit, whereas it has proved to be much more than a unit.
I found in 1922 that the most favourable sections for further investigation were those of the South Stack Series on the sea-cliffs of Rhoscolyn, especially under Rhoscolyn Hill, opposite the Maen-y-fran islets (G. of A., folding-plate ii). For, in the core of that major anticline, the beds are, as wholes, nearly horizontal for a quarter of a mile, which eliminates complication due to dip on major folding. The present paper is the outcome of some four weeks' study of the section in 1922 and 1923, followed by reexamination of the thermal aureoles of the basic intrusions of Holy Isle.
The original character of the rocks, their anamorphic condition, and their tectonics, have already been described. Here, therefore, it need merely be recalled that they were originally grits and shales; and that, as Rhoscolyn lies within one of the four anamorphic maxima of the Mona Complex, there are no catamorphic textures, but that all are now holocrystalline schists. Considered with regard to capacity for foliation, there are seven principal types :—(1) The massive green grits of the Stack Moor division of the South Stack Series (which are sometimes 30 feet thick); (2) the somewhat similar green grits
The Avonian Succession in the South of the Isle of Man
Authors: Lewis Herbert Price 
Published: October 2009

The Carboniferous rocks described in this paper occur within an area some 8 to 9 square miles in extent surrounding the ancient town of Castletown. The district is coastal and low-lying, a considerable portion being less than 100 feet above sea-level. The highest ground lies north-west of Ballasalla, where a few small tracts rise slightly above 200 feet.
The solid rocks are for the greater part obscured by a thick covering of drift, alluvium, or blown sand, and the chief outcrops are on the coast, usually between tide-marks. Most of the inland outcrops are confined to quarries lying west of the village of Ballasalla, to the Silver Burn, and to its tributary the Awin Ruy.
The heavy growth of seaweed and the honeycombing of the boring molluscs near low-water-mark render difficult the collecting of fossils, which, in many places, are also partly or totally destroyed by dolomitization, especially near the more important faults. Stretches of sand, shingle, and displaced joint-blocks break the continuity of the beds in the cliffs and on the foreshore, so that direct measurement of thickness is often impossible.
The Carboniferous rocks are bounded on the north-west by the Port St. Mary—Arbory Fault, which extends from Perwick Bay to near Ballashimmin (a distance of 5 miles), and with variable throw brings up the Manx Slate Series. Elsewhere on land the boundary is an unconformable or faulted junction with the Lower Palæozoic rocks. A similar junction probably exists a short distance below low-water-mark between the mouth of the
Petrographical Notes on the Geological Collection from the south Central Sahara made by Mr. Francis R. Rodd
Authors: Tyrell George Walter 
Published: October 2009

There are four volcanic rocks in the collection, two basalts and two trachytes. They all come from the volcanic region north and north-east of Auderas (Central Air), 1 which, from Mr. Rodd's mention of ‘isolated volcanic domes’ and ‘conical peaks’, appears to be of Recent, or, at the earliest, of Kainozoic age.
The two basalts are labelled ‘Tighummar’, a locality about 14 miles north of Auderas on Rodd's map. One specimen is of the porous character and pale-grey tint so frequent in Kainozoic and Recent basalts, and shows small phenocrysts of olivine and augite, the former weathering into yellow limonitic spots. The other rock is darker and more slag'gy in appearance, and is devoid of determinable phenocrysts.

In thin section the pale-grey rock proves to be an olivinebasalt, with sparse and small phenocrysts of almost colourless augite, sometimes showing a faint purplish tinge, and olivines with thick investments of red iron-ore. The olivine forms some phenocrysts as big as the pyroxenes, but all transitions in size can be traced down to numerous, small, hæmatized crystals which form part of the ground-mass. The ground-mass consists of plagioclaselaths and microlites (labradorite, Ab
2
An
3
), granular augite, and magnetite-cubes, together with the above-mentioned olivines. There is a small amount of turbid isotropic base. The felspars show well-marked flow orientation, and range in size from microlites to microphenocrysts.

The second rock approaches the ultrabasic basalts in composition. It shows numerous small phenocrysts of fresh olivine and augite. The latter is dictinctly publish, but many sections have