bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Geology of the Northern Border of Dartmoor between Whiddon Down and Butterdon Down
Authors: Osman Charles William 
Published: October 2009

In this paper the Lower Carboniferous formation bordering the granite of Dartmoor for a length of about 4½ miles, between Whiddon Down on the west and Butterdon Down towards the east, are the only stratified rocks dealt with; but the nature of, and variations found in the granite south of the Carboniferous rocks are also considered. The area examined includes part of the deep gorge of the River Teign, known as Fingle Glen, between Hunter's Tor and about a mile east of Fingle Bridge, or rather more than two-thirds of the length of the gorge.
The area described is covered by the 6-inch Ordnance Survey quarter-sheets of Devon:—LXXVII, S.E.; LXXVIII, S.W.; LXXVIII, S.E.; XC, N.W.; and XC, N.E. Of these quarter-sheets only the whole of LXXVIII, S.W. is covered; but portions of the other sheets are required to describe the area in a comprehensive manner.
In the area dealt with, the Lower Carboniferous, or Culm Measures, may, as found by Mr. R. H. Worth (10) in the granite-border south-west of Okehampton, be divided into two groups: the Lower Aluminous Series and the overlying Calcareous Series. Both these series of rocks have been affected by contact-meta-morphism from the granite.
The Lower Aluminous Series in this district can be divided into zones: the lower zone characterized by the occurrence of much segregated or disseminated iron-pyrites, and the upper zone in which chiastolite is found.
The Lower Aluminous Series passes upwards by gradual change, and without any physical feature, from black slates into
Upper Viséan Corals of the Genus
Caninia
Authors: Lewis Herbert Price 
Published: October 2009

The present research forms part of the investigation that is being made into the structure, affinities, and distribution of the Upper Viséan Caninoid corals. The majority of the specimens were examined at the Department of Geology, University of Sheffield. I express my great indebtedness to Prof. W. G. Fearnsides for the facilities for research which have been provided and for the interest that he has shown in my work. For much help in photography, and in a great many other ways, I cordially thank my colleague Mr. W. H. Wilcockson. Mr. W. J. Rees has also assisted me in photographic work.
Prof. S. H. Reynolds very kindly conducted me over the Avon section, and for other help in the field I tender my thanks to Prof. E. J. Garwood, Miss E. Goodyear, Dr. E. Neaverson, Mr. W. H. Wilcockson, and to my brother, Mr. C. C. Lewis, who has on several occasions assisted me to collect material in North Wales.
The bulk of the material examined was the result of my own collecting. For material which has proved of much assistance I am indebted to Miss I. Balmforth, Prof. P. G. H. Boswell, Prof. W. G. Fearnsides, Prof. E. J. Garwood, Miss E. Goodyear, Dr. F. L. Kitchin and the Director of H.M. Geological Survey, Dr. W. D. Lang, Dr. E. Neaverson, Prof. S. H. Reynolds, Principal T. F. Sibly, Dr. Stanley Smith, Dr. F. S. Wallis, Mr. W. H. Wilcockson, Mr. H. Woods and the Sedgwick Museum, Sir Arthur
The Volcanic Series of Trefgarn, Roch, and Ambleston, Pembrokeshire
Authors: Thomas Herbert Henry , Cox Arthur Hubert 
Published: October 2009

The area dealt with in this communication and represented by the appended map (Pl. XL) is situated some 5 miles north of Haverfordwest, 7 miles south of Fishguard, and from 8 to 14 miles east of St. David's. About 25 square miles in extent, it lies immediately north of a district recently resurveyed by the officers of H.M. Geological Survey, and south and east of a tract of country surveyed by one of us (in collaboration with Prof. O. T. Jones) in 1912. It is occupied mainly by Arenig and associated Upper Cambrian rocks, of which the Arenig Series is of especial interest, since it contains two distinct sets of volcanic rocks—one of which immediately underlies the lowest visible Arenig sediments. In addition, an important series of rhyolitic lavas and ashes of uncertain age traverses the greater part of the district from Roch to Trefgarn.
As is usual in Pembrokeshire, the general strike is in an east-north-easterly to west-south-westerly direction; but strike-faulting on an intensive scale has greatly disturbed the geological succession, and complicated the structure of the district. On the south, this area of Arenig and Upper Cambrian rocks is followed by extensive outcrops of the higher Ordovician beds of the Haverfordwest district, while its northern boundary is constituted, in large measure, by the pre-Cambrian massif of Hayscastle.
Topographically, the district is rather more varied than is usually the case in Western Pembrokeshire. Considerable portions of the area are occupied by the 400-foot plain; but out of this Topographically
Conditions of Deposition of the Stockdale Shales of the Lake District
Authors: Marr John Edward 
Published: October 2009

I. Introduction.
A detailed account of these shales was written by the late Prof. H. A. Nicholson and myself, and some remarks upon their mode of deposition were made therein; but some further notes may be useful to those who are interested in the physical conditions under which sediments were accumulated.
The beginning of the deposition of the Coniston Limestone marks the start of a long period of sedimentation, characterized essentially by the accumulation of fine muds with nodular bands of limestone, as noted by Prof. O. T. Jones. The Caradocian portion of the Coniston Limestone contains much detrital matter of coarse character, with interbedded limestones; but in Ashgillian times the sediments were much finer, and these fine muds continued almost uninterruptedly, save by the above-mentioned limestones, to the end of Wenlock times. There are fine grits in the Browgill division of the Stockdale Shales, and the nodular limestone-bands are almost absent in the Brathay Flags, of Wenlock age. Otherwise, conditions of sedimentation, so far as supply of mechanical material is concerned, were very similar in Ashgillian, Valentian, and Lower Salopian times; and graptolites are found in the deposits of these three periods.
Details of the sediments of Ashgillian age will be found in a paper by myself, and of the Stockdale Shales in the paper to which reference has already been made. The following tabular statement summarizes the facts:—
The wide distribution of these argillaceous sediments in this country and abroad, presenting generally similar characters where-ever found, indicates
River-Terraces of the Lower Valley of the Warwickshire Avon
Authors: Tomlinson Mabel Elizabeth 
Published: October 2009

I. Introduction.
Since the early part of the 19th century, the gravels which occur in the valley of the Warwickshire Avon have attracted attention. Strickland was one of the earliest workers on these deposits. He made many detailed observations, and recognized two main types of gravel. The high-level deposits which were unfossiliferous, and covered the hills, he considered to be of marine origin, while those occurring in the valley from 20 to 40 feet above the river, and containing mammalian remains and freshwater shells, he believed to be fluviatile (1, p.103).
Strickland attempted no further classification of the freshwater deposits; but his work is of great value, in that he carefully collected and identified organic remains from exposures, the position of which he described so accurately that they can be located at the present time almost with certainty. Strickland published lists of these fossils, together with their localities, and these have been extremely helpful in the work covered by this paper.
About 1875 a paper was published by T. G. B. Lloyd (3) describing certain additional exposures in these gravels, but otherwise adding little to Strickland's work as regards the Avon river-deposits.
Lucy (4) also described some new exposures in the Avon gravels. He states that two terraces containing mammalian remains occur in these valleys, one at 15 to 25 feet and the other at 40 to 50 feet above the present rivers; but he makes no reference to this statement in his subsequent description of the gravels. His paper
The Silurian Rocks of the Central Part of the Clwydian Range
Authors: Woods Ethel Gertrude , Crosfield Margaret Chorley 
Published: October 2009

I. Introduction.
In 1906 it was suggested to us by Dr. (now Professor) J. E. Marr that we should examine the little-known series of ‘Denbighshire Grits and Flags’ in the Clwydian mountains, and endeavour to establish the sequence of the beds. Between the years 1906 and 1909, and again in 1911, we paid a series of short visits to the range, working between the New Mold Road on the south and Caerwys on the north, covering an area of 72 square miles.
Various circumstances then prevented the continuance of our field-work until, in 1922, we decided to revisit the district and to put on record the palæontological evidence that we had so far obtained of the age of the beds, in the hope that it might be of service to future workers. Owing, however, to the rarity and very poor condition of the fossils, the map is admittedly incomplete, and some of the results are tentative.
We desire to thank very cordially Miss G. L. Elles and Dame Ethel Shakespear for kindly determining graptolites from two or three critical localities, and Prof. Marr for encouraging us to persevere. We also feel very grateful to Mr. W. B. R. King, with whom we have discussed some of the problems raised by the mapping, and whose suggestions have been very helpful.
The area described in this paper has Moel Fammau for its centre, and includes the range from the north side of Moel Llŷs-y-coed to Gyrn, a distance of about 5 miles
The Geology of Sierra Leone
Authors: Dixey Frank 
Published: October 2009

I. Introduction.
The territory of Sierra Leone in British West Africa comprises a Colony and a Protectorate, covering a total area comparable with that of Ireland. The Colony consists mainly of a mountainous peninsula about 25 miles long and 9 miles in mean width. The Protectorate can be divided physiographically into a low-lying coastal plain, and an interior upland region composed of a series of broken plateaux [11]. The mountains of the Colony, rising abruptly from the seaward margin of the coastal plain, consist of a great noritic complex [9]. The main outcrop of the older schists and gneisses, as well as that of the Rokell River Series, falls entirely within the limits of the coastal plain [12]. The upland plateaux are composed of a group of great granite-masses, mostly younger than the schists and gneisses of the coastal plain [12]. In the north-western corner of the Protectorate, near Saionia, the southern margin of the great plateau of horizontal sandstone that extends over a large part of French Guinea runs for a few miles along the Anglo-French boundary [8].
The main outcrop of the older schists and gneisses extends along the coast of the Protectorate, from French Guinea to Liberia. It is extensively overlain by clays, sands, and gravels of Pleistocene and recent age; consequently, except along the beds of the larger rivers and on the flanks of low hills scattered over the plain, the ancient basement-rocks are very poorly exposed.
In most respects these older schists and gneisses do
A Composite Dyke from Eastern Iceland
Authors: Guppy Eileen Mary , Hawkes Leonard 
Published: October 2009

I. Introduction.
A Copious literature exists relating to the phenomena of composite dyke-and-sill intrusions, mainly based on a study of the Tertiary rocks of Ireland and Scotland. Composite sills have not yet been noted in Iceland, but composite dykes occur quite commonly in the Tertiary plateau-basalt series of the eastern part of the country. Most of them illustrate characteristics which have been reported from elsewhere, and no detailed account of them is desirable. The dyke here described exhibits, however, some unique features, which have seemed to us to warrant investigation.
The field work was carried out by the second-named author, during summer visits to Iceland in 1914, 1920, 1922, and 1924.
The only reference in literature to this occurrence is a note by Th. Thoroddsen of a ‘liparite-dyke,’ full of basalt-fragments, bordered on each side by basaltic dykes.
The outcrop gives rise to a deep cleft, in the cliffs on the north side of Breithdalsvik, known as Hökulvikurgil (Pl. XIX, fig. 1), about 300 yards east of Snaehvammur farm. The exposure of rock in the gill is continuous from sea-level to the summit of the ridge between Breithdal and Stothvarfjord—about 2400 feet high, with the exception of a break between 15 and 300 feet which is covered by talus and raised-beach material, and another at 400 feet due to gill-deposits.
The country-rocks are plateau-basalts, with partings of red lateritic rock, and a massive dolerite-sill comes in between 1450 and 1850 feet. The outcrop trends 7° east of north. It does
On the Clay Pebble-Bed of Ancon (Ecuador)
Authors: Brown Charles Barrington , Baldry Robert Ashley 
Published: October 2009

The clay pebble-bed was first noted by one of us (C. B. B.) in 1919. It was further examined, and part of the outcrop mapped by him in 1922, when its nature and origin were realized. Mr. A. J. Ruthven Murray completed the mapping later. The authors of this paper examined the bed again in 1923, when final conclusions as to its mode of origin were reached.
The outcrop is limited in extent, covering not more than 2½ square miles; the numerous small areas are separated by tracts of stratified beds. The best exposure is along the sea-cliffs of Ancon Bay, on the south of the Santa Elena Peninsula. This peninsula is at the northern extremity of the Gulf of Guayaquil, 70 miles west of the town of Guayaquil, and some 130 from the main Andean chain.
A typical hand-specimen shows polished rounded or subangular pebbles of harder clay embedded in a matrix of softer clay. The ‘clay-pebbles’ vary from the size of a pin's head up to pieces 2 or 3 inches in diameter, and in rare instances the larger ones themselves contain smaller clay-pebbles. They are easily picked out of the matrix, leaving a smooth polished cast covered by a film of iron-staining. Both pebbles and matrix are grey; the films are grey, green, or brown.
In the mass, as in cliff-sections, the clay pebble-bed is seen to contain, in addition, big and partly rounded boulders of sandstone, foraminiferal limestone, and pebbly grit, 2 or 3 feet in
The Geology of the Rhobell Fawr District (Merioneth)
Authors: Wells Alfred Kingsley 
Published: October 2009

I. Introduction
A study of the existing geolagical maps of North Wales reveals at the south-eastern ‘corner’ of the Harlech Dome, inside the main Ordovician outcrop, a group of hills which, although composed of igneous rocks, do not appear to form an integral part of the ‘ring of fire’, from which they are separated by a narrow belt of Cambrian slates. The study of the geology of this group of hills, centred about Rhobell Fawr, and involving the investigation of the character of the rocks, their age, and relationship to those of the main Ordovician escarpment, has attracted several geologists before the present research was under-
taken at the suggestion of Prof. A. H. Cox. The position of Rhobell Fawr in relation to other districts recently in North Wales is shown in the appended sketch-map (fig. 1). The district examined lies within the parish of Llanfachreth, and has been mapped on the 6-inch Scale. The quarter-sheets covered by
the geological map illustrating this paper are Merioneth xx S.E.; xxvii S.E. ; xxviii N.W. ; xxviii S.W. ; xxiii S.E. ; xxxiii N.E. ; xxxiv N.W. ; and xxxiv S.W.
The stratigraphical succession ranges from low down in the Ffestiniog Beds to the Bala Mudstones. The former occur in the west, while the regional dip brings higher beds in towards the east. The central physiographic feature is the Rhobell mountain-mass, composed chiefly of volcanic material of early Arenig age. The mountain-mass comprises the central peak of Rhobell Fawr (240S feet) and
The Liassic Rocks of We Radstock District (Somerset)
Authors: Tutcher John William , Trueman Arthur Elijah 
Published: October 2009

I. Introduction.
The Liassic rocks described in this paper are those found within a radius of about 4 miles of Radstoek. The area dealt with is a low plateau, about 400 feet high, capped by Oolites and dissected by a number of rather narrow valleys. The Lias quarries are generally situated just below the plateau-level; the valleys are usually in deep red Keuper Marl, but in some of them the horizontal Mesozoic rocks are seen resting on gently folded Coal Measures, which have long been worked in the neighbourhood.
The Liassic rocks of this area have attracted considerable attention, because they are unusually thin, and in the lower part, exceptionally fossiliferous. The Lower Lias (Hettangian, Sinemurian, anjl Lower Charmouthian) is exposed in a great number of small quarries in the neighbourhood, and as each of these shows the entire succession from White Lias to Charmouthian, considerable detail concerning the sequence is available.
The peculiarities of the Liassic rocks of the district result from the fact that the area is situated immediately north of the Mendips; it is well known that there was repeated movement along this axis, intermittently from post-Carboniferous times until well into the Mesozoic. The consequences of these movements are seen at Radstock:

(i)
in the condensed development of certain Liassic zones ; the whole of the Lias thins as it is traced from Gloucestershire southwards to the Mendips, and from Dorset northwards.

(ii)
in the numerous non-sequences which have resulted mainly from
Fossil Plants from the Nubian Sandstone of Eastern Darfur
Authors: Edwards Wilfred Norman 
Published: October 2009

The plant-remains described here, and now deposited in the Department of Geology, British Museum (Natural History), were collected in 1924 by Mr. G. V. Colchester, Assistant Geologist to the Sudân Government, to whom I am indebted for the opportunity of examining them, and for the following particulars of their occurrence.

The fossils were found at Jebel Dirra, about 75 kilometres (47 miles) east of El Fasher. Jebel Dirra rises about 300 feet above a plain of Archæan rocks, and itself has a granitic core, with soft mica-schists on the northern face. It is capped by horizontally bedded sandstones, fractured blocks of which cover the south-western face of the hill. The plant-remains, which are very fragmentary, were collected partly
in situ
at the summit and partly from the loose weathered blocks just mentioned; they occur in a highly silicified quartzitic sandstone, and are the first fossils to be found in Darfur in the Nubian Sandstone.

Although only two species have been definitely recognized, they afford strong evidence for assigning these beds to the Lower Cretaceous System, or possibly to the base of the Upper Cretaceous, and their discovery is, therefore, of considerable importance. One or two blocks contain fragmentary invertebrate fossils, which appear to be quite indeterminable.
Some small fragments of this plant are sufficiently well preserved to show the rounded pinnules, about 6 mm. in length, attached by the whole base, with a thick lamina and anastomosing venation (fig. 1, p. 95). Other fragments, not showing the venation quite so
The Faunal Succession in the Carboniferous Limestone and Bowland Shales at Clitheroe and Pendle Hill, (Lancashire)
Authors: Parkinson Donald 
Published: October 2009

The present paper records an attempt to establish a faunal sequence in the Carboniferous deposits in the Clitheroe district of North-East Lancashire.
The area dealt with forms a small part of the large spread of Carboniferous strata lying south of the Craven Faults. The rocks of this region have been thrown into a series of more or less parallel folds with a general trend from east-north-east to west-south-west. The most important upfold is the Clitheroe Anticline, dissected by the Ribble, which runs west-south-westwards in the neighbourhood of Clitheroe, exposing the Carboniferous Limestone along the axis. On the north-western flank the synclinal Millstone-Grit hills of Longridge, Waddington, and Grindleton connect the Clitheroe Anticline with that of Slaidburn, in Bowland; while on the south-east there is a continuous succession through the grits of the Pendle Range to the Coal Measures of the Burnley Basin.
The ground which has been mapped in detail forms that portion of the south-eastern limb of the Clitheroe Anticline which is included between the Twiston and Clitheroe Faults, along with most of the scarp-face of Pendle Hill below the Pendle Top Grit. Two small patches occur on the Yorkshire side of the county boundary.
The low ground between the Ribble and Pendle Hill is occupied by the Clitheroe Limestone and the overlying ‘Shales-with-Limestone’ or Worston Shale Series. The upper part of the Clitheroe Limestone contains some of the typical reef-knolls which rise abruptly above the general level of the ground. One of these, Worsaw Hill, attains a height
The Sratigraphy and Structure of the Cambrian Slate-Belt of Nantlle, (Carnarvonshire)
Authors: Morris Thomas Owen , Fearnsides William George 
Published: October 2009

The area described forms the south-western portion of the Cambrian slate-range of North-Western Carnarvonshire, and comprises about 10 square miles of the drift-littered country of Western Snowdonia. The hills on the north-west side of it consist of igneous rocks referable to some late pre-Cambrian volcanic group. The uplands on the south-east are of Ordovician sedimentary material, topped by the rhyolites which form the steep scarp-face of Garnedd Goch.
Within this region, the general strike of the pre-Cambrian, Cambrian, and Ordovician rocks alike sweeps in a gentle curve from a north-easterly direction in the part of the slate-range north of the Llyfnwy, to a direction only a little south of west in the western portion of the district. This trend is nowhere in exact accord with the east-and-west course of the glaciated trough which contains the Llyfnwy valley and the lakes and village of Nantlle.
As recorded upon the accompanying map (Pl. XVIII), exposures of solid rock are not particularly abundant in the area. Only locally (as, for example, on Clogwyn Melyn) are connected outcrops continuous over more than a few hundreds of square yards. Within the exploited slate-belt, artificial excavations furnish more than nine-tenths of the solid ground exposed, and even with these additions the total exposed area is only about a tenth of the infra-Drift extent of the slate-range. Fortunately, the depth and measurements mad during the survey of artificial exposures that the present conception of the structure of the region has been gained. The contoured index-map (fig. 1,