bluuebunny/crossref_metadata_2025 huggingface dataset:
The Ballachulish Fold near the Head of Loch Creran (Argyllshire)
Authors: Bailey Edward Battersby
Published: October 2009

The main features of the tectonics of the Loch Creran district have already been delineated in a paper dealing with a more extended region, and published in 1910 by the Geological Society of London. The results of this earlier work, brought up to date, are epitomized in the map (p. 322), which will serve as an index of the relations of the district to neighbouring portions of Argyllshire and Inverness-shire.

The original mapping of lower Glen Creran was carried out by Mr. H. Kynaston and the late Mr. J. S. Grant Wilson. Before preparing the paper just cited, I visited the district on two or three occasions, once accompanying Mr. C. T. Clough, and at another time Mr. H. B. Maufe. Various alterations in the mapping were made as a result of these traverses, and it was found that the more essential structural features were readily determinable in the light of evidence furnished by the country to the north-east. At the same time, it was apparent from the first that anything like detailed knowledge could only be attained as a result of systematic re-examination, involving a considerable expenditure of time. A favourable opportunity for further work arose officially during the past season, when observations were made which seem worthy of record as an illustration of the complexity locally recognizable in the Highland Schists.

Two main difficulties are encountered in the field: there are many slides (fold-faults), so many, in fact, that the original stratigraphical sequence has to be accepted from
The Scandinavian Drift of the Durham Coast and the General Glaciology of South-East Durham
Authors: Trechmann Charles Taylor
Published: October 2009

I. Introduction.

The present paper deals with some matters of interest among the glacial phenomena in the area of South-East Durham, between Seaham Harbour and the mouth of the Tees and the sea-coast on the east, and a line drawn north and south from slightly west of Durham to about Darlington. The area is represented on the Geological Survey 1-inch (Drift) Sheet 103 N.E. (new series, Sheet 27) and Sheet 103 S.E. (new series, Sheet 33).

The most novel information in the present account is that concerning a basal drift and the fact that the ice which transported it was apparently the earliest on this part of the East Coast. This ice has left its record (among other phenomena) in a bed of shelly clay, the erratics of which seem to be solely Scandinavian in origin. The fauna of this clay bears Arctic affinities, and recalls that which occurs in the shelly basement-clays of Flamborough Head and Holderness. The appellation of Scandinavian Drift for this bed is therefore, I suggest, a thoroughly justifiable one.

A description of the somewhat problematical sand- and gravel-beds, containing in one instance a rather large proportion of schistose and other rocks (apparently of Scottish origin) underlying the main Cheviot Drift, follows.

A brief description of the main Glacial Drifts, more especially in connexion with the extent of the Cheviot glaciation and direction of its flow in the last stage, is also added.

The history of the discovery of the long-suspected occurrence of Scandinavian boulders on
A Composite Gneiss near Barna (County Galway)
Authors: Cole Grenville A. J.
Published: October 2009

The great area of granite, probably of pre-Cambrian age, stretching west from Galway town, includes a variety of rock-types, some of which are of composite origin. Gneisses (foliated granites) occur along the northern margin, the foliation, marked out by their dark constituents, being parallel with the bedding of the adjacent metamorphosed sediments. Dr. C. Callaway observed in 1887, near Glendalough (Recess), phenomena similar to those which have since formed the basis of the ‘stoping’ theory of intrusion, and he noted how ‘the granite has intruded between the strips of diorite and pushed them apart, without materially disturbing their parallelism.’ He records the coincidence of the foliation in the Galway granite with that of the enclosing schists, and attributes this to pressure acting during the consolidation of the mass. It is remarkable that he did not take the further step of pointing out how the strike of the sedimentary series has influenced that of the foliation in the igneous invader.

Composite rocks, where diorite has become included and streaked out in the granite, occur in the west of Townparks townland, in the demesne of St. Mary's College in Galway town. Some of these are referred to in the Memoir of the Geological Survey of Ireland [1869] accompanying Sheets 105 & 114, where Kinahan (p, 25) treats the whole as a metamorphosed sedimentary series. Prof. Watts describes some of the diorites as ‘doubtless intrusive into the granitite,’ a conclusion that does not seem to be sustained by the field-evidence. Kinahan (
op. cit.
The Rocks of the Lyd Valley, above Lydford (Dartmoor)
Authors: Mennell Frederic Philip
Published: October 2009

I. Introduction.

Considering that Dartmoor is the largest of English granite-masses, and displays almost every possible type of contact-metamorphism along its margins, its extensive literature contains surprisingly little detailed information regarding the features presented by the rocks at different localities round the Moor. Indeed, it may be said that, for an area so rich in points of interest, it has been much neglected by petrologists. Local workers are very few, and before the issue of the Geological Survey Memoir on Dartmoor there was no reliable summary of the various rock-types that were to be found. The petrographical contribution by Dr. Flett & Mr. Dewey has now supplied the want of a general account of the granite and its modifications, and of the rocks which constitute the metamorphic aureole round about it. Over much of the area covered by the Dartmoor sheet of the map, further work would now be chiefly of local interest: it happens, however, that the whole of the northern margin of Dartmoor is outside the area mapped, and that it presents some special features of its own. Moreover, the examination of the contact-zone in this northern area serves to suggest that detailed petrographical work on the distribution of the various rock-types may help materially in solving many questions as to the subdivision and succession of the Carboniferous strata. These have hitherto proved insoluble, owing to the lithological similarities and the general absence of fossils, as well as the numerous dislocations, in other parts of Devon. This paper
On a New Eurypterid from the Belgian Coal Measures
Authors: Stainier Xavier
Published: October 2009

Remains of
Eurypterus
are quite uncommon in the Coal Measures, and more especially in Belgium, where, until recently, none had been recorded. When studying, with R. P. G. Schmitz, the cores of one of the numerous trial-borings put down in the new Campine Coalfield of Northern Belgium, we found a beautiful specimen belonging, without any doubt, to this interesting genus of fossil Merostomata. We recorded this discovery some years ago (Schmitz & Stainier, 1910). Availing myself of the opportunity of examining the excellent material available in England, the classic country for fossil Crustacea, I now venture to publish a description of the new species.

The splitting of the cores has disclosed the crustacean lying amid scattered remains of undeterminable plants on a fine-grained, greyish-brown, micaceous shale. The animal has the same dark coloration as the surrounding plants. Owing to a blow of the hammer, the counterpart of the fossil is fractured and incomplete, and therefore of little use for palæontological purposes. But, fortunately, the impression of the dorsal aspect is in an excellent condition. It is to be regretted that the fossil has been partly destroyed by the diamond drill, the consequence being that some portion of its abdomen and the entire telson are altogether wanting.

Dimensions:—This new species is one of the smallest Carboniferous Eurypterids known, its maximum length being only 33 millimetres and its maximum breadth 12 mm.

Cephalic shield.—Length=8 mm. Breadth at the posterior border=11 mm.

The head is not the best-preserved part of the fossil, and
On a Fossiliferous Limestone from the North Sea
Authors: Newton Richard Bullen
Published: October 2009

Through the good services of Mr. R. W. Thomson, of the Fishery Office, Aberdeen, the British Museum has been placed in possession of two blocks of limestone, one of considerable size, crowded with the remains of marine shells, which had been obtained from the bed of the North Sea by the steam-trawler, the ‘Procyon,’ commanded by Captain Wood, some 80 miles east of Orkney or 100 miles north-east 1/2 north of Buchan Ness.

In order to acquire further information as to this unique occurrence, I communicated with Dr. A. W. Gibb, the Curator of the Geological Museum of Marischal College, Aberdeen, who kindly sent me some interesting particulars on the subject. He was familiar with the rock, having had a sample forwarded to him by Dr. Bowman, the scientific investigator on the North Sea Fisheries' boat, the ‘Goldseeker,’ who from considerable experience had gained some knowledge of the physical characters of the floor of the North Sea. Dr. Bowman informed Dr. Gibb

‘that at the spot where it [the limestone] occurs, there is what seems to be a gorge or submerged channel of some kind, with much deeper water than in the adjoining sea, and he thinks that there is a considerable mass of the rock in all probability [
in situ
?], as trawlers report that they frequently break their gear upon it.’

Although found beneath the sea, this limestone nowhere displays any unusual abrasion, its aspect being entirely that of a rock which might have been
On some Insects from the British Coal Measures
Authors: Bolton Herbert
Published: October 2009

The present paper consists of a critical study of some hitherto undescribed wings of fossil insects from the British Coal Measures, and of insect-wings previously noted by other authors. I am indebted to Mr. William Eltringham, of Newcastle-on-Tyne, and to the authorities of the Geological Survey Museum, the National Museum of Wales, and the Liverpool, Manchester, and Newcastle Museums for their courtesy in placing the specimens at my service for study.

This specimen was obtained by Major Chambers, and presented to the Derby & Mayer Museums, Liverpool, in 1858. It is contained in an ironstone nodule, much similar to those of Ravenhead (Lancashire). Its horizon is not known, but it is undoubtedly from the Middle Coal Measures. It was partly described and named, but not figured, by S. H. Scudder in 1885; and a figure of the wing appeared in the same year in Zittel's ‘Handbuch der Paläontologie.’ This figure was probably due to Scudder, who wrote the entomological section of the work for that edition of Zittel's manual.

The wing lies in a fine-grained ironstone nodule, one half showing a left wing, and the other half of the nodule containing the impression. Since the specimen came into my hands for examination, I have been able to uncover the apex of the wing and a small portion of the base. A little of the base of the wing is missing, and also the middle portion of the inner margin. The total length of the wing as now seen is 87
On the Origin of some River-Gorges in Cornwall and Devon
Authors: Dewey Henry
Published: October 2009

The river-gorges here described are situated for the greater part in North Cornwall, between Boscastle and Tregardock, though a few occur in other parts of Cornwall and in Devon. Some of the characteristics of the coastal gorges of Devon have already been described by Dr. E. A. N. Arber, but there appear to be additional features in those of North Cornwall, which are possibly due to their mode of origin.

These gorge-like valleys are more or less restricted to areas of peculiar topography, and their origin is connected with the history of that topography; while they form a sharp contrast with the valley-systems where such a topography does not exist. Thus, the valley-systems of Cornwall are divisible into two groups, each being marked by features peculiar to it; although in some cases the river-valley exemplifies the two types of scenery in different parts of itself.

The difference is in part due to their respective stages of development, but mainly marks a renewal or rejuvenescence of the rivers' activity. The fall of these rivers near Tintagel averages 1 foot in every 13 feet.

The Upland Plain.

The gorges are incised in an upland plain, which truncates all hills at a uniform height of about 430 feet above the level of the sea, while the other series of valleys lies in an area diversified by many irregular hills and buried and submerged estuaries.

This feature has become well-known in Cornwall through Clement Reid's descriptions. It is everywhere bounded landwards by a prominent
The Pseudotachylyte of Parijs (Orange Free State), and its Relation to ‘Trap-Shotten Gneiss’ and ‘Flinty Crush-Rock’
Authors: Shand S. James
Published: October 2009

I. Introduction

In the year 1913 I received from a former student of mine, Mr. P. H. S. De Wet, a consignment of rock-specimens from the neighbourhood of Parijs (O.F.S.). Among these were many pieces of a dense black rock, which, I was informed, occurs very abundantly in veins and networks in the granite. The characters of this rock seemed so remarkable that I took an early opportunity of visiting Parijs myself, in order to study the phenomena in the field. As a result of my observations, I formed the opinion that the black veins were intrusions of basic magma which had entered the granite by a process of stoping, accompanied by corrosion and solution; and a paper embodying this conclusion was communicated to the Geological Society in November 1914, an abstract of it appearing in the Proceedings of the Society for that month (No. 964). After the manuscript had left my hands, I became aware for the first time of the work of Sir Thomas Holland and his colleagues of the Geological Survey of India on the ‘trap-shotten gneiss’ of Salem, Madras, and I could not fail to be struck by the resemblance between some of the phenomena there described and those observed by me. My attention was next turned to the ‘flinty crush-rocks’ of the Cheviot Hills and other parts of Scotland, which were also at one time held to be of igneous origin. By the kindness of Dr. Flett, the late Dr. Clough, and Mr. E. B.
Aulina rotiformis
, gen. et sp. nov.,
Phillipsastræa hennahi
(Lonsdale), and
Orionastræa
, gen. nov.
Authors: Smith Stanley
Published: October 2009

I. Introduction

Phillipsastræa
is a genus of Devonian Corals possessing certain well-marked characters. The genus
Orionastræa
has been established to include certain Carboniferous species very closely related to
Lithostrotion
, but which have been regarded by many writers as congeneric with those of
Phillipsastræa. O. phillipsi
(McCoy) is commonly known as
Ph. radiata
(Martin).

Aulina
is a new genus, found at the horizon of the Millstone Grit. One species only has been recognized: this has been confused hitherto with
O. phillipsi
, and hence recorded as
Ph. radiata
. I regard
Phillipsastræa
as the ancestor of
Aulina
, but do not consider that these are related to
Orionastræa
.

All three genera, however, are colonial in habit, and possess a similar type of corallum: namely, that in which the individual corallites have lost their epitheca, and consequently are united by their dissepiments—a type of colony which may be termed ‘astræiform.’

The foregoing statements explain my reasons for including the history of the name
Phillipsastræa
and the description of its genotype in a communication primarily concerned with Carboniferous genera.

I am deeply indebted to the late Prof. T. McKenny Hughes, to Dr. A. Smith Woodward, Dr. F. L. Kitchin, Dr. W. G. Lee, and Mr. Peter MacNair for the loan of material (including various type-specimens) preserved in the Sedgwick Museum, Cambridge, the British Museum (Natural History), the Museum of Practical Geology, the collection of the Geological Survey of Scotland, and the Glasgow Museum & Art Gallery; and to Mr. Charles Edmonds, Prof. E. J. Garwood, and
Fourth Note on the Piltdown Gravel, with Evidence of a Second Skull of
Eoanthropus dawsoni
Authors: Woodward Arthur Smith
Published: October 2009

The Piltdown gravel has already been well described by the late Mr. Charles Dawson,
1
who pointed out its variable character and concluded that its two lower layers at least could not be very different in age.
2
Further extensive excavations last summer round the margin of the area previously explored, tended to confirm this impression, and to show that the whole deposit is a shingle-bank which may have accumulated within a comparatively short space of time. The lenticular patches of the dark-brown ferruginous gravel proved to be even more variable than before, and they were seen to pass both into the sandy clay below and into the less clayey deposit above. Large flints and waterworn pieces of Wealden sandstone were still observed scattered irregularly through the finer material. The characteristic ‘subangular flints’ were also found at intervals in the basal sandy clay. More interesting, however, was the discovery in this layer of numerous large elongated flints and pieces of Wealden sandstone, with their long axis more or less nearly vertical. The evidence of flood-action thus became complete.

Although so much of material was carefully examined, neither bones nor teeth were met with. The only noteworthy find was a battered nodule of black flint, which occurred in a rather sandy patch of the dark-brown gravel resting immediately on the basal layer. This specimen, which is conspicuously different from the other flints and very little stained, may have been used by man as a hammer-stone (text-fig. 1). It measures nearly 13 centimetres in
The Microscopic Material of the Bunter Pebble-Beds of Nottinghamshire, and its Probable Source of Origin
Authors: Burton Thomas Harris
Published: October 2009

I. Introduction.

Samples of sand were carefully collected from all the principal exposures on the outcrop of the Pebble-Beds in Nottinghamshire. It was cleaned in hydrochloric acid, sifted, and then separated by means of Thoulet's Solution having a specific gravity of 2⋅77. Enough of each sample (namely, 2 ounces) was taken to give a heavy residue sufficient to weigh and to mount as permanent objects for the microscope.

II. Physical Characteristics of the Sand.

The sand in the exposures is more or less coherent, in many cases taking on the appearance of hard rock. It may, however, when dislodged (the cement being mainly ferric oxide) be easily crumbled, often between the fingers.

At depths of 102, 211, and 307 feet, cores at the Farnsfield borehole, near the Midland Railway Station, showed the rock to be compact, hard, and very calcareous Microscopic examination proved this to be the only real difference when compared with samples taken from the exposures.

The sand varies in texture and colour, coarse-grained material largely predominating; but the following distinct types may be recognized:—

1. A coarse sand, whitish yellow to buff and brown in colour, found in most exposures.

2. A reddish sand of medium coarseness, found in all the principal exposures.

3. A dark brownish-red sand of fine texture, used for moulding purposes, found especially at Whisker Hill Quarry near Retford, and at Bestwood Warren.
1

Samples
2
were all taken from No. ‘2.’ Ordinary bedding may be observed, but false bedding is
On the Geology of the Old Radnor District, with special reference to an Algal Development in the Woolhope Limestone
Authors: Garwood Edmund Johnston , Goodyear Edith
Published: October 2009

I. Introduction.

The district which forms the subject of this communication has received but scanty attention in geological literature since the time of Murchison. Only one edition of the 1-inch Geological Survey map has been issued, namely, that published in 1840, and no explanatory memoir has yet appeared. Two of the horizontal sections published by the Geological Survey, however pass through the district, and these throw some light on the views adopted by the officers of the Survey regarding its general structure at the time when the district was mapped. They regarded the rocks of Old Radnor Hill as altered May Hill Sandstone, and the surrounding limestone, together with that which occurs at Nash Scar 3 miles away to the north-east, as altered Woolhope Limestone.

Murchison, as shown by his description in ‘Siluria,’ considered the district to be one of especial interest. He draws attention to the differences exhibited by the limestone at Nash Scar and Old Radnor, when compared with the normal Woolhope Limestone and Shale at Corton and Haxwell, and remarks, ‘between these two …. lies the large and loftier rock of Nash Scar, in which the same limestones, whether thick-bedded or nodular, have been run together into one amorphous mass, in which the stratified character has been destroyed, and the shale driven off. …. In tracing the strata southwards along this axis, other masses of limestone, more or less amorphous, are seen near Old Radnor, which, in proportion as they approach the eruptive masses of Stanner and
A Seasonal Variation in the Frequency of Earthquakes
Authors: Oldham Richard Dixon
Published: October 2009

When investigating the aftershocks of the great Indian earthquake of 1917, I found that the ratio of shocks occurring during the day half of the twenty-four hours, between 6 a.m. and 6. p.m., to those occurring during the night half, was somewhat greater than the general average during the summer months, when the sun is in north declination, and somewhat less during the winter months, when the sun is south of the equator. As this relation was found not only in the whole record, but also in the natural groups of observations, it seemed probable that the variation was a real one, and not fortuitous; while the fact that the record of the Shillong seismograph, when tabulated by lunar times and seasons, gave a similar variation suggested that the cause was not climatic, but in some way connected with the tidal stresses set up by the attraction of the sun and the moon.
1

At a later date I made a tabulation (which has not been published until now) of Milne's catalogue of Japanese earthquakes,
2
and again found a similar relation between the ratio of day to night shocks in the two halves of the year; and a similar tabulation of the records from a number of observatories, mostly independent of and covering a later period than Milne's catalogue, again gave the same result.

Recently there has appeared an abstract tabulation of twenty years' records of observations, carried on by the Italian seismological service, which enables the subject to be more
The Geology and Genesis of the Trefriw Perites Deposit
Authors: Sherlock Robert Lionel
Published: October 2009

The mass of iron pyrites worked at Cae Côch, Trefriw (Carnarvonshire) appears to be unique in some ways, so far as Great Britain is concerned, consequently its geological characters are of some interest.

In August, 1917, Mr. T. C. Cantrill and myself visited Cae Côch, and as a result of what we saw I spent seven days in the following month in mapping geologically the area around the mine. In this work I received all possible assistance from Mr. E. J. Morris, F.G.S., the Manager of the mine, to whose energy the successful development of the deposit is due. To him I wish to return my thanks, and also to Dr. H. H. Thomas for petrological notes and to Mr. John Pringle for naming the fossils.

The Geological Survey Map (Old Series 78 S.E.) published in 1852, shows a fault, or thrust, at the position of the ore-body, separating Bala Beds above from Contemporaneous Felspathic Trap (engraved F) below. The presence of pyrites is not recorded, nor is it mentioned in the accompanying memoir, probably because it is not seen at the outcrop owing to weathering. At the 4th milestone from Llanrwst the map shows a boundary-line, apparently a fault or thrust, bringing in the same ashes on the north, against Bala Beds on the south. In the memoir by A. C. Ramsay,
1
we read that north of the 4th milestone from Llanrwst volcanic ashes form all the high ground for about a mile in width, as far as Llanbedr.
The Shap Minor Intrusions
Authors: Morrison James
Published: October 2009

I. Introduction.

An investigation on the minor igneous intrusions of the south-eastern part of the Lake District was commenced by the writer in 1913, the Shap area being first selected for study. The results of the work in that neighbourhood were such as to indicate the desirability of extending the investigation into the adjoining areas on the east and north. The work has not yet been completed, prevalent conditions having considerably interfered with its progress. It is perhaps advisable, therefore, to place on record the results so far obtained, leaving the remainder to be dealt with on some future occasion.

The Shap granite has long been of interest to geologists, its marked porphyritic character and conspicuous basic segregations having quite early attracted attention. Little, however, of any moment concerning it was published before 1868, when H. A. Nicholson's paper ‘On the Granite of Shap in Westmorland’ appeared.
1
This was followed in 1875 by a series of papers by J. Clifton Ward on the granitic rocks of the Lake District, in one of which their origin was discussed, the work of Sorby being taken as a basis.

It was not, however, until 1891 that the results of a detailed investigation by Dr. Harker & Prof. Marr on the granite and its associated rocks appeared in the Quarterly Journal of this Society—a comprehensive study, both of the granite itself and of the effect produced on the surrounding rocks by its intrusion.

While the plutonic mass has thus received the attention that it
The Inferior Oolite and Contiguous Deposits of the Crewkerne District (Somerset)
Authors: Richardson Linsdall
Published: October 2009

I. Introduction.

In this paper I propose to give a detailed description of the Inferior Oolite and contiguous deposits of the Crewkerne district. The extent of this district, for the purpose of the present communication, will be observed from the map (fig. 1, p. 146).

(i) Geographical extent of the Inferior Oolite.—Reference to the Geological Survey Map, Sheet XVIII (Old Series) will show (1) that the most extensive tract where the Inferior-Oolite limestones occur, free from overlying rocks, is in the immediate neighbourhood of Crewkerne; (2) that there are numerous masses well separated from the principal tract; and (3) that the beds are affected by numerous faults.

(ii) Previous literature.—Comparatively little information has been published concerning the Inferior Oolite and immediate sub- and superjacent deposits of this district, with the exception of Ham Hill. This locality, famous for its warm-coloured building-stone, attracted considerable attention on the part of Charles Moore,
1
James Buckman,
2
and H. B. Woodward.
3

The second author was correct in his local correlations of the Ham-Hill Stone—a conclusion also arrived at by H. B. Woodward —but was incorrect in his correlation with the Cotteswolds; although his recognition of the Cephalopoda-Bed below the Sands at Midford (near Bath) and around Yeovil, but above the Sands of the Cotteswolds, came nearer to the truth than was imagined. The actual solution arrived at by Mr. S. S. Buckman—published with a descriptive section in 1889
4
—that the Ham-Hill Building-Stone and its subjacent sands were a thick development of only a small middle portion
The Chellaston Gypsum Breccia in its Relation to the Gypsum-Anhydrite Deposits of Britain
Authors: Smith Bernard
Published: October 2009

I. Introduction.

It is now generally accepted that the extensive beds of gypsum that occur in this country are the deposits of salt lakes or inland seas, and the opinion has been steadily growing that the sediments with which they are usually associated are the products of weathering of an arid region.

In recent years the geographical conditions of the periods when gypsum was deposited have been discussed by numerous writers, including Beasley, Bosworth, Burns, Geikie, Goodchild, Hewitt, Jukes-Browne, Lomas, Metcalfe, Wade, and Watts. The object of this communication is not so much to discuss the geography of these periods, as to throw some light upon the actual mode of accumulation of gypsum, chiefly from the standpoint of the field-observer.

In any question dealing with gypsum, however, it is almost impossible to avoid dealing also with the anhydrous form of calcium sulphate, since the two minerals occur so frequently in intricate and puzzling association. The main point at issue is whether gypsum is to be regarded as an original deposit, or as a secondary formation.

We may dismiss the isolated occurrences of gypsum which result from the decomposition of sulphides in rocks containing lime, as being a minor point well understood, and confine ourselves to the more extensice deposits occurring as beds and smaller masses, or as a matrix to the rocks in which the thicker deposits are found.

Various suggestions have been advanced to explain the origin of these deposits:—

(i) Some may be due to evaporation by concentration
The Highest Silurian Hooks of the Clun-Forest District (Shropshire)
Authors: Stamp Laurence Dudley
Published: October 2009

I. Introduction.

In the counties of Radnorshire, Montgomeryshire, Shropshire, and Herefordshire, rocks of Ludlow age have been indicated over considerable areas on the Geological Survey maps.
1
There are also several large outliers of Old Red Sandstone strata in this region, and both sets of rocks are crossed from Church Stretton on the north to beyond Presteign on the south by the great Church-Stretton Fault (see fig. 1, p. 222). This fault marks approximately the boundary between the shelly calcareous type of Silurian sediment in Shropshire and the argillaceous type in Wales. The Shropshire succession of Ludlow rocks has been studied in detail (most recently by Miss G. L. Elles & Miss I. L. Slater
2
), and the ground has been well known to geologists since the original work of Murchison.
3
On the other hand, the country immediately to the west of the great fault is little known, and no detailed account of the uppermost Silurian and Old Red Sandstone rocks has been published. Scattered references certainly exist, but they deal with the general characters of the district rather than with special features and definite localities.

It was, therefore, suggested by Dr. A. H. Cox that I should undertake an examination of the area, with the view of determining the sequence and distribution of the uppermost Silurian strata. These rocks are here of especial interest, since the district occupies an intermediate position between the Shropshire (Ludlow) district with its calcareous type of sediment, on the one side, and the Welsh area, where
The Geology of the Marble Delta (Natal)
Authors: du Toit Alexander Logie
Published: October 2009

The crystalline dolomitic marbles near Port Shepstone have formed the subject of no less than three communications to this Society.

That by C. L. Griesbach, written nearly half a century ago, gives us the first glimpses of this interesting occurrence; the next, by David Draper was fuller, but lacking in most of the important details; the third, by Dr. F. H. Hatch & Mr. R. H. Rastall is a particularly valuable contribution, especially from the petrographical standpoint: the intrusive relationship of the granite is placed beyond dispute, and the operation of the action known as dedolomitization is fully demonstrated.

Consequently, it is not inappropriate that the principal conclusions arising out of the geological survey of the area (carried out in 1915–16) should be communicated through the same channel, especially as they confirm and amplify the expressions of Hatch & Rastall as to the nature of the metamorphic actions involved.

The sole point of disagreement concerns the ‘boulder’ of alkali-granite, which, from the evidence available, can only have formed part of an intrusive tongue in the marble, while the other reputed instances of ‘inclusions’ must be placed in the same category.

The object of the present paper is the description of this and certain other cases, where there has been an actual transfer of material from the intrusion across the contact to the rock invaded, a rather infrequent phenomenon, and one termed ‘contact-metasomatism’ by J. Barrell, and ‘pneumatolytic contact-metamorphism’ by Y. M. Groldschmidt; the action termed ‘calcitization’ is also described and
Description of the Nox-Marine Mollusca
Authors: Kennard Alfred Santer , Woodward Bernard Barham
Published: October 2009

Nineteen species of mollusca were sent to us by Dr. Trechmann, which he had obtained by washing the clay. The species were:—

Succinea putris
(Linnaeus). Rare.

S. pfeifferi
Rossmässler? Do.

Limnæa pereger
(Müller). Common.

L. palustris
(Müller). Hare.

L. truncatula
(Müller). Do.

L. stagnalis
(Linnæus). Do.

Planorbis lævis
Alder. Common.

P. crista
(Linnæus). Do.

P. umbilicatus
(Müller). Rare.

P. leucostoma
Millet. Do.

Valvata piscinalis
(Müller). Common.

V. cristata
Müller. Rare.

Unio
sp. Do.

Anodonta cygnæa
(Linnæus). Do.

Pisidium amnicum
(Müller). Do.

P. casertanum
(Poli). Common.

P.
cf.
lacustris
B. B. Woodward. Do.

P. nitidum
Jenyns. Do.

P. subtruncatum
Malm. Do.

P. hensloicanum
(Sheppard). Do.

Since there is an almost total absence of characteristic species, it is difficult to speak definitely as to the age of the bed. They are all living forms, but the abundance of
Planorbis lævis
shows that we are dealing with a deposit of some antiquity. If we judge from the known facts, the bed may well be the equivalent of the Cray ford Brickearths or rather later.

Valvata piscinalis
is not known to occur at an earlier horizon, and, although the examples
The Pleistocene Deposits around Cambridge
Authors: Marr John Edward
Published: October 2009

Since the year 1910 I have devoted considerable attention to the Pleistocene Deposits of the Cambridge district, and believe that my observations will be useful as an aid to future students of these accumulations.

In a paper read before the Cambridge Philosophical Society in 1917, I gave a brief account of the conclusions which I had reached, and noted the importance of a study of the Pleistocene deposits of the Great Ouse Basin,

‘for in this area we get evidence of the relationship of the Palæolithic deposits to those which were formed during a period of submergence and re-emergence, and also to accumulations which give evidence of the occurrence of more than one cold period.’

In the present paper I propose to confine myself to a consideration of the deposits in the immediate neighbourhood of Cambridge, with special reference to the sequence of the various members of the Pleistocene accumulations as there displayed (see fig. 1, p. 205).

In the previous literature devoted to this subject undue stress has been laid upon relative elevation above present river-level. Of recent years it has been recognized that, owing to alternate erosion and aggradation, difference of level must be treated cautiously, for reasons which I gave in the paper to which I have referred. The researches of palæontologists have enabled us to construct a timescale based upon fossil evidence (including that furnished by human implements), and I have relied largely upon this evidence in attempting to determine the time-sequence of our local deposits.
Appendix I. The Non-Marine Mollusca of the Cambridgeshire Gravels
Authors: Kennard Alfred Santer , Woodward Bernard Barham
Published: October 2009

The first list of mollusca from the Pleistocene deposits at Barrington was published by Mrs. T. McKenny Hughes in 1888 and enumerated twenty-four species. In 1911 Prof. T. McKenny Hughes recorded twenty-seven species, and added some details regarding one of the species. In 1918 one of us (B. B. W.) mentioned six species of
Pisidium
, five of which were new records. Several visits have been made to this deposit, and a large amount of material has been washed, the conditions existing at the pit greatly facilitating this work. We are, therefore, now able to register fifty-four species, as follows:—

Limax maximus
Linné. Five examples.

L. arborum
Bouchard-Chantereaux. Abundant.

Agriolimax agrestis
(Linné). Common.

Milax gagates
(Draparnaud). One example.

Polita nitidula
(Draparnaud). One example.

P. pura
(Alder). Two examples.

P. radiatula
(Alder). Two examples.

Zonitoides nitidus
(Müller). One example.

Euconulus fulvus
(Müller). Common.

Arion
sp. One granule.

Punctum pygmæum
(Draparnaud). Abundant.

Pyramidula rotundata
(Müller). Two examples.

Helicella virgata
(DaCosta). Common.

H. itala
(Linné). Common.

Hygromia hispida
(Linné). Abundant.

Acanthinula aculeata
(Müller). Three examples.

Vallonia pulchella
(Müller). Common.

V. excentrica
Sterki. Common.

V. costata
(Müller). Common.

Helicodonta obvoluta
(Müller). Two

Helix nemoralis
Linné (fragments). Common.
Geological Sections through the Andes of Peru and Bolivia: II—From the Port of Mollendo to the Inambari River
Authors: Douglas James Archibald
Published: October 2009

I. Introduction.

In a former communication to this Society, published in April 1914, I described a geological section through the South American Andes, from Arica on the Pacific coast of Northern Chile to the Bolivian Yungas.

The present paper, the publication of which has been long delayed owing to the War, is a further contribution to the same series, the result of work undertaken on the Baiston Expedition to Peru. It deals with a second and parallel section drawn through the south of Peru from the port of Mollendo to the River Inambari, a tributary of the Madre de Dios, one of the head-waters of the Amazon. That part of the country illustrated in the western half of the section, which includes the important town of Arequipa and the port of Puno on Lake Titicaca, is accessible by the Southern Railway of Peru, of which we were enabled to make full use during the course of our work from Arequipa to the coast, through the kindness of Mr. McCulloch, manager for the Peruvian Corporation. I have also to thank Mr. F. A. Corry, chief engineer of the line, for the original from which the sketch-map (fig. 1) was taken.

For the continuation of the section beyond Puno through the Eastern Cordillera, it was found necessary to proceed northwards as far as Tirapata, a station on the Puno-Cuzco railway, whence access could be gained, by the trail of the Inambari Rubber Company, to the forested region of the Montana.

The railway
A Comparative Review of Pliocene Floras, based on the Study of Fossil Seeds
Authors: Reid Eleanor Mary
Published: October 2009

I. Introductory.

The work on which the following paper is based has been rendered possible only by the help received from many botanists. If it were not for a considerable private collection of seeds and fruits, mounted for microscopic examination, it would have been impracticable, either to gain the knowledge requisite for carrying out, the work, or to make the preliminary determinations, which are necessary before it is possible to use the great collections of our public herbaria.

The formation of this collection of seeds, though initially, and essentially, due to my late husband's careful and unwearying labour, has for some years passed the bounds when the work of any single collector could meet the demands of the study of fossil seeds. Help has, however, been received from all sides: by gifts of specimens from Kew (both the Gardens and the Herbarium), the British Museum, the Herbarium of the Muséum d'Histoire Naturelle, Paris, and the Gardens of La Mortola; also by contributions from botanical friends, among whom I would especially mention Mr. James Groves, Mr. C. E. Salmon, Mr. T. A. Dymes, M. Émile Gadeceau, M. J. Simon, and Dr. Tokotaru Ito.

As well as for contributions to my collection, I would also thank the officers of Kew and the British Museum, for their unfailing kindness in helping while I have been at work in the respective Herbaria, and in lending specimens for photography and study.

Of late my work has been greatly furthered, particularly the photographic part of it,
A Natural ‘Eolith’ Factory beneath the Thanet Sand
Authors: Warren Samuel Hazzledine
Published: October 2009

Experiment has shown that the mechanical movement of one flint grinding against another under pressure will produce edge-chipping similar in every respect to that which is seen upon the Eoliths.

Direct evidences that such processes have actually been in operation in Nature have been brought forward by M. I'Abbé H. Breuil
1
and Mr. F. N. Haward,
2
as also by the present writer
3
; but more comprehensive knowledge of the work of Nature is urgently needed.

One must never forget that static energy in equilibrium is ineffective: there must be some disturbance of equilibrium for any chipping force to be set in action. That is to say, there must be at least vibration, but the greater the differential movements, and as a consequence the more the stones grind over each other, the more favourable the conditions become for the production of edge-chipping.

Certain types of superficial drift fulfil these conditions, through the, prolonged operations of soil-creep, better than they can be fulfilled in more deeply seated situations. But the Eoliths that are found in them, which some investigators believe to be results of these mechanical movements, can always be claimed by others as human implements.

The conditions at the base of the Tertiary System do not always fulfil what is needed. The section at Harefield can be taken as a good illustration: here is evidence of immense pressure, without any appreciable amount of differential movement. In consequence we find that the fractures are promiscuous, and strike through the heart of
On the Junction of Gault and Lower Greensand near Leighton Buzzard (Bedfordshire)
Authors: Lamplugh George William
Published: October 2009

I. Introduction.

Eighteen years ago the late J. F. Walker and myself described to the Society a remarkable fossiliferous limestone occurring immediately beneath the Gault at Shenley Hill near Leighton Buzzard. The bed differed, both in its lithological characters and in its fossil contents, from any other deposit then known at this horizon in England, and the problems which it presented demanded, and have received, further investigation. Walker continued assiduously to explore the palaeontology of the bed, until his work was cut short suddenly by death in 1907. Partly by personal visits to the locality, but mainly through the agency of the quarrymen, he had been able by this time very largely to increase his collection of the fossils, and had made progress in his study of the brachiopodfauna, which was his particular interest. It was his intention ultimately to deal exhaustively with this element of the fauna, and, as a preliminary step, he had already prepared and sorted many thousands of specimens into their proper specific relationship, with provisional determinations where possible. The collections thus arranged by his own hand are, however, all that remains to us of the work that he did after the publication of our joint paper. Some information culled from them will be given in a later part of the present paper.

While my late colleague continued to explore the palaeontology of the Shenley bed, I devoted attention, as before, more particularly to its stratigraphical aspect. Visits in successive years constantly revealed new features of
The Structure of the South-West Highlands of Scotland
Authors: Bailey Edward Battersby
Published: October 2009

I. Introduction.

The gradual development of structural interpretation in regard to the South-West Highlands of Scotland has much in common with the long-continued building of some great cathedral. The workers have been many, each with his own individuality, and each influenced by the spirit of his time. In these circumstances, preparatory demolition has been an almost inevitable feature of every attempt at improvement. But one is emboldened to the task by the thought that restoration can be carried out if occasion proves its need: a fairly representative literature enshrines the observations and opinions of the long line of researchers.
1

Statement of the Problem.

As a preliminary to discussion, the following dogmatic statement is offered. The schists of the South-West Highlands of Scotland belong to three main structural divisions, which, in descending order, are (fig. 1, p. 84 & Pl. 1):—

Loch-Awe Nappe,

Iltay Nappe,

Ballappel Foundation.

The first title is derived from Loch Awe. The second is a hybrid of Islay and Loch Tay. The third is compounded from Ballachulish, Appin, and Loch Eilde.

Each great division has its particular stratigraphical facies, although there are certain correspondences which suggest stratigraphical correlations from one to another.

The Loch-Awe Nappe is relatively simple in structure. The Iltay Nappe includes two important recumbent folds—the Ben-Lui Fold, a syncline closing towards the north-west, and the Carrick-Castle Fold, an anticline closing towards the south-east (fig. 4, p. 102 & Pl. 1). The Ballappel Foundation is a structural complex, with the Ballachulish and Appin Nappes among
The Bala Country: its Structure and Rock-Succession
Authors: Elles Gertrude Lilian
Published: October 2009

I. Introduction.

The district dealt with in the present paper lies all round Bala Lake, though attention has been paid more particularly to the ground lying south-east and east of the lake, as affording an opportunity for the study of problems of special interest regarding the succession and structure of the area.

The whole district has been classic ground since the days of Sedgwick, and its difficulties were vividly described later by Jukes; it is just these difficulties that make the area so intensely interesting, and, largely owing to the more detailed mapping that can be carried out in these days, it is now possible to suggest a solution of some, at any rate, of the problems—more particularly those of a stratigraphical and structural nature. The palæontological problems are somewhat different, and will not be dealt with in detail at present.

Previous Work.

By far the most important contributions made to our general knowledge of the district are those of Sedgwick, Jukes, and Ruddy, though Ramsay and, in later times, Lake have dealt with the question of the faulting as connected with the development of the valley in which the lake lies.

Sedgwick made two important contributions to the study of the area. In the earlier paper on the ‘Calcareous Slates & Limestones of Glyn Dyffws on the Holy head Road, west of Corwen, & of Rhiwlas north-east of Bala,’
1
he gave what he believed to be the succession in the area, and illustrated it by sections made as early