bluuebunny/crossref_metadata_2025 huggingface dataset:
Mineralogical Notes [on River-Gravels of the Oxford District]
Authors: Spiller Reginald Charles
Published: October 2009

All collected from the brick-works at Wolvercote.

The Warp is a yellowish-brown sand with a small amount of yellowish mud, which was easily removed by washing to leave a clean light-brown sand. The sand was concentrated by panning, and separated with bromoform, giving an abundant crop of heavy minerals. Very little mica was seen in the washings, or in the concentrate. Sifting showed the presence of a small percentage of grains too large to pass a 30-mesh sieve. These consisted of quartz, subangular and rounded, ferruginous concretions (limonite?), chert-like fragments and lydian-stone. The minerals present in the lighter portion of the concentrate were quartz, felspar (microcline and orthoclase), and muscovite (scarce). The heavy minerals observed were garnet and zircon (abundant), tourmaline, rutile, staurolite, cyanite, epidote, and andalusite. Magnetite, ilmenite, and leucoxene were abundant.

No effervescence was observed on treatment with hydrochloric acid.

The River-Silt is a sandy clay, the proportion of clay apparently increasing with the depth from winch the sample is taken. The clay is pale blue, with irregular yellow patches. On being washed and boiled, the clay breaks down into a yellow mud, leaving a light greyish sand which contains a good deal of mica. All the sand passed through a 30-mesh sieve. Concentration by panning and separation with bromoform gave an abundant crop of heavy minerals. The lighter portion contained subangular and rounded quartz, felspars (microcline and orthoclase), muscovite, and a few grains of chert. The heavy minerals observed were garnet and zircon (abundant), tourmaline, rutile, staurolite,
The Avonian of the Tytherington-Tortworth-Wickwar Ridge, Gloucestershire
Authors: Wallis Frederick Stretton
Published: October 2009

The Author describes and maps, in terms of Vaughan's system of zonal classification, the northern portion of the horseshoe-shaped wooded ridge of Avonian rocks which partly surrounds the synclinal basin of the Bristol Coalfield lying north-east of Bristol.

The area described links together the researches of two former papers, and completes the Avonian zonal map of the horseshoe ridge.

The chief zonal characteristics may be summarized as follows:—

Cleistopora
Zone.—Lithologically the zone consists of shales. grits, and thinly-bedded muddy limestones, with the usual fossils. The Bryozoa Bed (α) has been recognized, and the zonal fossil is unusually abundant in the Tytherington-Grovesend railway section.

Zaphrentis
Zone.—Limestones of the ‘Petit Granit’ type, with intervening shales in Z
1
, form the major part of the sequence. At the base of Z
1
in the Tytherington-Grovesend railway section is an interesting band of oolite. No chert has been found. Zaphrentids are very abundant, and the ‘Z
2
Fish-Bed’ occurs in the northern part of the area. Horizon γ cannot be differentiated, owing to the absence of
Caninia
immediately above the
konincki
subzone.

Syringothyris
Zone.—The following sequence occurs in ascending order:—

(1)

Thickly-bedded, nearly unfossiliferous. blue-grey dolomites (
laminosa
dolomites), apparently formed by the dolomitization of crinoidal limestones.

(2)

A series of fossiliferous crinoidal limestones (Sub-Oolite Bed): non-oolitic in the lower, but oolitic in the upper portions.

(3)

A thick bed of current-bedded white oolite (
Caninia
Oolite). This was probably immediately followed by a short period of subaërial denudation.

(4)

Unfossiliferous thinly-bedded dolomites, with subordinate shales (
Caninia
Dolomites).

Series (2) and (4) a.re considerably thicker than their eqnivalents in the Avon Section.

Seminula
Zone.—The zone consists of massive limestones, including examples of ,
Seminula
Pisolite, china-stones, and
Seminula
Oolites merging into sandstones and conglomerates of a ‘Millstone Grit’ phase of deposition. A calcareous sandstone (Firestone) occurs near the base of S2 (formerly described from the top of Sl).

A calcareous development of the
Dibunophyllum
Zone is absent in the area described.

It is thus established, from the evidence of previous writers and that set forth in the present paI)er, that during Avonian times there was a progressive movement of the northern shore-line of Vaughan's ‘ South-Western Channel ’ in a southerly direction. This movement is registered by noting the level in tile Avonian sequence at which ‘ Millstone Grit’ conditions were established.

The maximum thickness of the calcareous Avonian beds is only 1280 feet, as compared with 2540 feet in the Avon section.

The Tytherington-Grovesend railway provides a complete section of the Avonian rocks of the area.
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
On a Hybodont Shark (
Tristychius
) from the Calciferous Sandstone Series of Eskdale (Dumfries-Shire)
Authors: Woodward Arthur Smith
Published: October 2009

The Elasmobranchs of the Carboniferous Period, already known by more than isolated teeth or spines, are very different from all the Elasmobranchs of the Mesozoic and Kainozoic Eras. Some of them approach the theoretical ancestors of the sub-class in their internal anatomy and in the skeletal supports of their fins; others are peculiar in the development of bilaterally symmetrical plates in the cranial roof, or in the presence of dermal head-plates; others seem to have a dentition intermediate between that of the Selachii and the Holocephali, which have been distinct orders since Jurassic times ; and a few form an unique group in which at least the symphysial teeth do not fall out when done with, but fuse with their successors and hang in front of the mouth, either forming a complete spiral or falling away at occasional intervals. Only one specimen has been briefly noticed that seems to approach more nearly the later types of sharks, and this is now worthy of detailed study and description.

The specimen in question is the anterior portion of a small shark shown of the natural size in fig. A (p. 339), and it was referred by Traquair to
Tristychius
, probably
T. arcuatus
Agassiz. It is displayed on the counterpart halves of a slab of shale from the Calciferous Sandstone Series of Eskdale (Dumfries-shire), and is now in the Royal Scottish Museum, Edinburgh. I am indebted to Dr. James Ritchie, Keeper of the Natural History Department, for the opportunity of investigating it. The
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
Age and Origin of the Lough Neagh Clays
Authors: Wright William Bourke
Published: October 2009

In the years 1918 and 1919 the Department for the Development of Mineral Kesources made an attempt to solve the problem of the concealed extension of the Tyrone Coalfield by putting down a bore near Coalisland. One of the secondary results obtained from a study of the cores was an approximate solution of the old question of the age of the Lough Neagh Clays. These clays, as is fairly generally known, occupy the ground around Lough Neagh in the North of Ireland; but, being for the most part at a very low level, and covered by a thick mantle of drift, they are poorly exposed. Previous to 1875, and recently to a less extent, they were exploited for pottery purposes by means of open and bell-shaped pits, and E. T. Hardman records a number of sections obtained in this way. The only organic remains obtained from these pits were fragments of wood and woody tissue so highly carbonized as to be quite unidentifiable, and affording no trustworthy evidence of age. From general considerations, such as their superposition on the basaltic lavas, and the fact that they are overlain by the glacial drift, Hardman concluded (but apparently not without misgivings) that the clays were Pliocene and laid down during a period of greater extension of the present lake. The evidence now available relegates them to the Older Tertiary, and indicates that their deposition was previous to the Miocene folding and faulting, so that their apparent association with the lake may be
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
On Cyathoclisia
,
a
New Genus
of
Carboniferous Coral
Authors: Dingwall Janet Mitchell Marr
Published: October 2009

In this paper are described certain Tournaisian coral-forms of limited range, which are fairly abundant in some localities in the South-West of England and South Wales. These resemble
Clisiophyllum
in their general features, but differ so markedly from the Visean species of that genus in structural details, that it seemed desirable to apply to them a new generic name:
Cyathoclisia,
proposed by Dr. W. D. Lang, is here adopted.

On the suggestion of Prof. A. H. Cox, I began to investigate the coral fauna found in the Carboniferous Limestone of Little Island, Barry (Glamorgan). Later, however, Principal T. F. Sibly pointed out that the ‘Clisiophyllids’ might prove worthy of detailed study, and this paper embodies the greater part of the results obtained in following out his suggestion. In addition to the material from Barry, specimens and sections from Bristol, the Mendips, and Ireland have been examined.

For the loan of specimens I cordially thank the following:— The Keeper of the Geological Department, National Museum of Wales, Cardiff, for material collected by Principal Sibly and presented by him to that Museum; the Keeper of the Geological Department, British Museum (Natural History); the Keeper of the Geological Department, Royal Scottish Museum, for Clisiophyllids; Mr. G. E. Bush; Prof. E. J. Garwood and Miss E. M. Goodyear, for specimens of
Clisiophyllum
from the North-West of England; Mr. T. N. George, for Clisiophyllids collected in Caermarthenshire; Mr. T. A. Ryder and Dr. Stanley Smith, for sections prepared by them; and Dr. L. B. Smyth,
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 Black Marl of Black Ven and Stonebarrow, in the Lias of the Dorset Coast
Authors: Lang William Dickson , Spath Leonard Frank
Published: October 2009

The Black Marl series of the Dorset coast was so named by the officers of the Geological Survey to include the shales and limestones lying above the stone-beds of the Blue Lias and below the pale marls of the Belemnite Beds. I have already given a detailed account of the Shales-with-‘Beef’—the lowest part of the Black Marl series. But a detailed account of the sequence above the
birchi
bed is much needed; and, although our knowledge of the contained fossils and their order of occurrence is still incomplete, yet a particular description of these horizons as represented on the Dorset coast should help to unravel the sequence in the corresponding Lias of other areas, especially in view of the amount of work which is now being done on the Lias, and of the use already made of the Dorset sequence in such work. In this connexion much has been heard of non-sequences. It is hoped that this paper will show the importance of this principle in interpreting the Lias; yet to what error it may lead if rashly applied.

I need hardly indicate how barren the detailed observations and descriptions of the paper would be without the accurate (even if approximate) determinations of the ammonites. Indeed, except from the view-point of lithology, detailed description of the beds is only necessary in order that the exact positions of the contained fossils may be recognized. The experience and the knowledge reuired to determine specimens as poorly preserved as most o those collected
Notes on some New or Incompletely-known Ammonites
Authors: Spath L.F.
Published: October 2009

Of the ammonites enumerated in Dr. Lang's stratigraphical part, a number have already been discussed in separate papers. These ammonites include the
Oxynoticeras
of the
lymense
bed: that is, O.
lymense
Wright sp.,
O. winqravei
Spath,
O. reynesi
Pompeckj (Spath, 1925
a
), and the
Gleviceras
of the
raricostatum
zone. The latter unfortunately have not vet been collected in sufficient numbers to be definitely separated from the typical Gloucestershire species of the (post-
varicostatoides
)
subplanicosta
beds. The genus
Asteroceras
Hyatt also has already been discussed (Spath, 1925
e
), but
A. margaritoides
Spath may now be figured,. also several
Arietites
, including three of the new species previously (Spath, 1923, table to p. 84) recorded from the uppermost beds of the Shales-with-‘Beef’. Of the other genera of the super-family Ammonitida (=‘Arietida’) that range up into the Black Marl,
Cymbites
may shortly be referred to.

Epophioceras
Spath is so far known in only a few examples from the ‘Limestone with Brachiopods’ and from probably equivalent beds inland.
Eparniocerus
, again, has already been dealt with (Spath, 1925
g
).

The various stocks of the second great super-family of the Lower Lias (Deroceratida), include Xipheroceratids. with
Microderoceras, Xiptieroceras
, and
Promicoceras
, further Deroceratids in the restricted sense, with
Eoderoceras
and
Deroceras
, and Microceratids (
Crucilobiceras
), all previously discussed. It will only be necessary to figure a few new species of these genera. My thanks are due to Dr. W. D. Lang for the opportunity of dealing with his ammonite material.

This species is common enough and familiar to collectors in
Notes on the Brachiopoda
Authors: Muir-Wood Helen Marguerite
Published: October 2009

Brachiopoda occur at several horizons in the
obtusus
and
raricostatus
zones, but they are frequently distorted or crushed, and therefore unidentifiable. Crushed Rhynchonellids belonging to two distinct species occur in bed (77 a). One form (B 45789) can be referred to
Squmirhynchia
(?)
belemnitica
Quenstedt, and has the typical coarse angular plication and squamose surface. The other form (B 45782-88) is semiplicate. The Upper Cement-Bed (82) yields well-preserved specimens of
Spiriferina walcotti
(James Sowerby) (B 45797, B 45780) and vars. (B 45798), also a
Spiriferina
resembling S.
pinguis
(Zieten), but with fewer plications on the lateral slopes (B 45799).

Rhynchonellas occur abundantly in the Limestone with Brachiopoda (87).

These include elongated, anteriorly plicated Forms with Hypothyrid beak and indistinguishable from Quenstedt's species
Piarorhynchia gryphitica juvenis
from the Sinemurian (B 45811). A massive globose form with a Mesothyrid beak, usually much incurved, belongs to the genus
Tropiornynchia
Buckman (B 45807-809). A third form resembles ‘
Rhyncnonella’ lineata
Young & Bird from the Domerian (B 45806, B 45810, B 45812,B 45818-19).

In the
raricostatus
zone a well-preserved specimen of ‘
Rhynchonella’ triplicata fronto
Quenstedt (B 46308) was obtained from the Watch Ammonite Stone (99), and crushed Rhynchonellids (B 45820) from the clays above the large nodule-bed (102).

A single imperfect Terebratulid (B 46309) referable to the genus
Lobothyris
Buckman, and resembling
L. radstockiensis
(Davidson) from the Charmouthian was obtained from Hummocky (103 a).
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,
The Geological Structure of Ben Lawers and Meall Corranaich, (Perthshire)
Authors: Elles Gertrude Lilian
Published: October 2009

The present paper may be said to deal in particular with Ben Lawers and Meall Corranaich, and in general with the whole of the Ben-Lawers range lying between the Bridge-of-Balgie Fault on the east, and the Loch-Tay Fault on the west; for, while the structures seen on those two mountains are undoubtedly typical, certain features there observed only attain their full significance when viewed in the light of what is seen elsewhere on the range.

The area is one of considerable relief, the range reaching its highest elevation in Ben Lawers (3984 feet), and having many summits above the 3000-foot level: it is deeply dissected by several glens, such as Glen Lochay, the Pass over to Glen Lyon west of Beinn Ghlas (Lochan-na-Larig Pass), and those occupied by the Allt Tuim Bhric (Carie Burn), and the Lawers Burn, on the south side; while on the north side of the range there are the Gleann Allt Da Eig and the Gleann Allt Chobhair.

The district was first surveyed by J. S. Grant Wilson, and his results, published on the 1-inch maps of the Geological Survey of Scotland (Sheets 46 & 47), afford much food for thought to later workers, who must always be grateful to these pioneers in mapping. No official description has, however, appeared, although we have been told by M. Macgregor that ‘it has long attracted the attention of geologists from its apparently obvious synclinal structure and from the possibility of its furnishing a clue to the structure of
Species of
Lepidocyclina
and
Carpenteria
from the Cayman Islands, and their Geological Significance
Authors: Vaughan Thomas Wayland
Published: October 2009

During the spring of 1924 Dr. C. A. Matley sent to the United States National Museum specimens of larger foraminifera and corals collected by him in the Cayman Islands. A few months later the collection was forwarded to me for examination and report, and in July, 1924, I sent to Dr. Matley a preliminary report. Nothing more regarding the corals need be said than was contained in my report to him; but it is desirable to accord more detailed treatment to the foraminifera, because the species represented, though already known, have not been adequately described and figured in any prior publication, and, in this connexion, an opportunity is offered to make clear a part of the basis of the correlation of an important geological horizon in the Gulf and Caribbean region of America. It is also pertinent to discuss a part of the technique in the study of larger foraminifera, and perhaps thereby render assistance to those who are studying the group, but have not yet become proficient.

Since this paper is intended primarily as a contribution to geological correlation, a note on what I have considered the proper procedure in the study of the American Tertiary formations may be appropriate. It is my belief that the first endeavour should be the correlation of the American deposits among themselves, and that, after this object has been achieved, correlation with more distant regions should be undertaken. Knowledge of the many horizons recognizable in the American Tertiary deposits is very inadequate, notwithstanding
Anthracopupa Britannica
sp. nov., a Land Gastropod from the Red Beds of the Uppermost Coal-Measures of Northern Worcestershire
Authors: Reginald Leslie
Published: October 2009

This paper records for the first time the occurrence of representatives of the Gastropod Order Pulmonata in the Carboniferous rocks of this country. Although several species of the group have been known for many years from rocks of Upper Devonian and Carboniferous age in North America, the only previous record from the Palæozoic rocks of Europe is that of one species, represented by a single fragmentary specimen, from the Lower Permian of France (see p. 405).

The specimens which are the subject of this paper were discovered by Mr. W. Wickham King, F.G.S., in January, 1924; I must express my appreciation of his kindness, both in inviting me to undertake their description, and in furnishing all the stratigraphical and other particulars of their occurrence. The shells described have been presented by him to the Geological Department of the British Museum (Natural History), a second series having been given to the Geological Survey.

For other information I am indebted to Mr. E. G. Carruthers, Mr. J. Pringle, Prof. P. Pruvost, Dr. A. E. Trueman, and Mr. T. H. Whitehead.

The localities to which reference will be made all lie on the northern slope of Clent Hill, in Northern Worcestershire (about 10 miles west-south-west of Birmingham), and are shown on the accompanying sketch-map (p. 402). The geological details in the map are a rather diagrammatic presentation of the results of recent mapping by Mr. King, but the Geological Survey 6-inch map (Worcs. 9 N.E.), published in 1924, should also be consulted, since
Stratigraphical Note
Authors: Fearnsides William George
Published: October 2009

Direct paæontological evidence for the determination of the exact zonal horizon of the Garth Grit, with its phosphate-masses. deposited in skeletons of Bolopora zmdosa, is not yet forthcoming. Across the Ffestiniog country the outcrop of the Garth Grit has been traced for at least 10 miles, but it nowhere appears as a continuous bed. In patches it is repeated by strike-faulting, and alternatively for hundreds of yards it is pinched out altogether. Nowhere is it more than 50 feet thick, and where it is thickest there is abundant evidence of shearing and gliding along the bedding-planes which separate successive massive beds. There is also abundant evidence at these localities that all or some of the beds have been reduplicated by minor thrusting. Bryn Glas and the quarry at Croes-y-Ddwy-Afon are both localities where the grit-beds have been piled together by series of reduplicating thrust-planes, and it is under these complex masses of grit that the slate-exploiters have opened their quarry-chambers ‘under the hard’. These are the only localities from which phosphate-masses and ‘nodules’ fresh enough to retain conclusive evidence of their bryozoal structure have yet been collected. The best specimens are from the roofs of those chambers which are near the lateral margins of the ‘schuppen’ lenticles.

Under these conditions all the larger grit-particles, pebbles, and phosphate-masses have adjusted their position within the slaty matrix, and have set their long axes end on to the direction of movement. In the phosphate-bearing conglomerate, the rock has in fact a marked polarity,
The Junction-Bed of the Middle and Upper Lias on the Dorset Coast
Authors: Jackson James Frederick
Published: October 2009

The object of this communication is to amplify and correct certain descriptions and sections of the Junction-Bed of the Middle and Upper Lias near Eypesmouth on the coast of Dorset, which I contributed as an appendix to Mr. S. S. Buckman's recent paper on Jurassic chronology.

On the Dorset coast the long time-gap between the top of the Domerian, in the Middle Lias, and the base of the Yeovilian, or Bridport Sands, in the Upper Lias, is represented by only a few feet of strata, and these vary greatly from section to section and even within a few yards. These few feet constitute the Junction-Bed, and fossils collected inch by inch in the different exposures show that, although all the hemeræ recognized by Mr. Buckman as filling this gap have not been found, yet representatives of many hemerae occur, some in one exposure and some in another, and always in their appropriate order; so that it is fair to assume that the period was one of continual oscillation and penecontemporaneous erosion, and that the strata present a succession of non-sequences. At least in one exposure, at Watton Cliff, a considerable non-sequence can be directly demonstrated in a single block; here a bed belonging to a definite horizon thins out completely between two beds of respectively earlier and later dates.

In order to make clear how much of the supposed complete sequence is represented and when the non-sequences occur, the following table is given, showing all the horizons of this date
A Revision of the British Carboniferous Murchisoniidæ, with Notes on their Distribution and Descriptions of some New Species
Authors: Longstaff Jane
Published: October 2009

In previous papers I have described many members of the Murchisoniidæ. Here I am referring briefly to the chief characteristics of some of the genera and subgenera into which this family has been divided, also indicating the holotypes and recording additional localities in numerous instances. Besides this, I am describing and figuring six new species and one variety, and noting the occurrence in the British Isles (as well as figuring) five species which were previously described by L. G. de Koninck in Belgium. One of the latter was entered in a list by the late Prof. T. McKenny Hughes, but no figure was given.

Altogether, fifty-two species and one variety are recorded from the British Isles, and of these seventeen are common to Belgium.

Sixteen species and one variety are referred to
Murchisonia
sensu stricto, three to
Aclisoides
, four to
Cerithioides
, one to
Caliendrum
, three to
Pithodea
, and twenty-five to
Hypergonia
. The greatest number has been found in Scotland (namely: thirty-one and one variety), and twenty of these appear so far to be confined to that country. It has been pointed out, when describing
Aclisina
, how wonderfully well preserved are the Scottish shells, and many have a texture and creamy coloration similar to those of much more recent age. On the whole, they are smaller than their representatives in other countries, but there are exceptions to this: for instance,
Murchisonia fusiformis
Phillips,
Hypergonia conula
, and
Aclisoides striatula
nearly equal in size specimens from Yorkshire, Poolvash, and Visé.

Nine specimens have