bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Geological Results of Measurements of Gravity in the Welsh Borders
Authors: Cook Alan Hugh , Thirlaway Henry Ivison Shipley 
Published: October 2009

Summary
The gravity measurements made by members of the Department of Geodesy and Geophysics of Cambridge University in the Welsh Borders from 1947 bo 1950 are described and the geological results discussed. The methods of measurement and the calculation of the gravity anomalies are not given in detail since they have already been discussed elsewhere. The data given in the paper in the form of a map of the Bouger anomalies are probably consistent to within ±0–25 mgl.
At the Malvern Hills the Bouguer anomalies change rapidly from about —25 mgl. on the east to about -(-5 mgl. on the west. A probable interpretation is that there is a deep basin east of the Malverns, filled mostly with Triassic rocks, reaching a depth of nearly 10,000 feet near Worcester and bounded on the west by a surface sloping down at about 45° from the Malvern Hills. It is suggested that the basin was formed by faults, the movement along which began in late Carboniferous times and ended in late Triassic times.
Large variations of anomaly in the Welsh Borders appear to have no relation to the known geology and are probably due to heavy Pre-Cambrian masses, particularly in the Black Mountains and near Leominster. The Church Stretton disturbance appears to be marked only by a slight maximum anomaly.
The Geology of the May Hill Inlier
Authors: Lawson James Dixon 
Published: October 2009

Summary

The May Hill inlier displays a calcareous and shelly development of Silurian rocks. The Upper Llandovery and Wenlock strata are similar, in general, to the corresponding beds of the Malvern and Woolhope area. The Ludlow beds, however, are remarkably thin (maximum thickness 250 feet); they are here divided into six divisions based mainly on faunal changes, and a correlation with the succession at divisions based attempted. Only the basal and the uppermost separated by an unconformity. The Aymestry Limestone is cut out by an unconformity at the base of the
Dayia
Beds, marked by a thin development of limestone-conglomerates. A phosphatized fragment-bed in the Upper Ludlow strata marks yet another important break in deposition. A distinctive faunal horizon at the base of the Upper Ludlow division, characterized by an abundance of the brachiopod
Shaleria
[
Brachyprion
]
ornatella
, has been traced throughout the Welsh Borderland and has been found most valuable for correlation.

Structurally, the May Hill inlier is a complex pericline situated at the junction of the Malvern and Woolhope axes; the main folding movements probably occurred in post-Westphalian—pre-Triassic times, with subsidiary and intra-Morganian movements.
The Pleistocene Epoch in England
Authors: King William Bernard Robinson 
Published: October 2009

Summary

A review of the evidence on the position of the boundary line between the Pliocene and Pleistocene is given. This leads to the acceptance of a boundary in England berween the Coralline Crag and the Waltonian division of the Red Crag. A plea is made for basing the boundary on stratigraphical rather than climatographical considerations. Since the evidence from the Midlands appears to be much more clear-cut than that in East Anglia, the former is taken as a starting point. The stratigraphy in the Thames basin is then considered in the light of the Midland deposits; the question of the succession and age of the oldest drifts raises problems clearly needing elucidation. These are further considered in connexion with the East Anglian drifts, where the importance of recent work is emphasized. The problems of the Newer Drift in the northern parts of England are reviewed. It is suggested that in the Midlands and northern England the
Corbicula-Hippopotamus
fauna probably occurs at only one horizon and that this lies between the Older and the Newer Drifts.

It is suggested that more objective thinking would be possible if the Alpine nomenclature of Penck & Brückner were not used in Britain, and that it might help if a committee were set up, not to try to formulate correlations, but to propound an agreed nomenclature for the English divisions of the Pleistocene deposits.
On the Geological Distribution of Carboniferous Blastoids in the Craven Area, Based on a Study of Their Occurrence in the Yoredale Series of Grassington, Yorkshire
Authors: Joysey Kenneth Alan 
Published: October 2009

Summary
An abundant Carboniferous blastoid faunain the Middle Limestone of the Grassington area, Yorkshire, has been used as the basis of a study of the geological factors which influence the distribution of blastoids.

In this area, Lower Carboniferous sedimentation was influenced by the craven fault-belt, which separated a shelf-sea over the Askrigg massif to the north from the rapidly subsiding craven basin to the south. In the northern part of the Grassington area the Cockleshell division of the Middle Limestone is characterized by bands of the brachiopod
Gigantoproductus
. When traced in the direction of the basin,
Gigantoproductus
decreases in abundance and finally disappears. The lower beds pass laterally into the knoll-bearing marginal facies. The knoll phase is succeeded by a crinoid-bank phase, which, on the massif side of the knoll region, contains abundant blastoids (
Orbitremites
and
Codaster
). An Orbitremites band has been traced northwards into the area characterized by
Gigantoproductus
.

The association between the occurrence of
Orbitremites
and the knoll-forming limestones is confirmed by other blastoid localities in the Craven area. Blastoids are abundant in the crinoid-bank deposits which cap the clitheroe knolls (C
2
), and also in the upper pat of the Whitewell knolls (C
2
). In the Slaidburn anticline
Orbitremites
has been found in shales (C
2
) which are the lateral equivalent of nearby knoll limestones.
Orbitremites, Codaster
and
Zygocrinus
have also been found in the marginal facies (D
2
) of the Malham area.
Plant Remains from the Gravels of the Summertown-Radley Terrace Near Dorchester, Oxfordshire
Authors: Duigan Suzanne L. 
Published: October 2009

Summary

Plant remains have been found at the base of gravels attributed to the lower part of the Summertown-Radley stage of the upper Thames Pleistocene succession, with which a mammoth fauna and Middle Acheulean implements are associated. The flora, which on the whole is similar to that of the district at the present time, includes a few species now restricted to northern or alpine regions, thus indicating a colder, although by no means an arctic, climate. In the Oxford district the lower gravels of the Summertown-Radley stage are succeeded by others containing an
Elephas antiquus
fauna; there is evidence of a later cold period, with which Acheulean implements are not associated.
The Disturbed Strata on the Fox Earth Coal and its Equivalents in the East Pennine Coal-Field
Authors: Shirley Jack 
Published: October 2009

Summary

During the course of outcrop-coal working occurrences of disturbed strata were noticed at Swallow Nest, near Sheffield. These were in the roof strata of the Fox Earth Coal, which is in the Lower
similis-pulchra
Zone of the Middle Coal Measures. The relations of the disturbed strata showed that they owed their structures to contemporaneous phenomena and that the disturbances were completed before the deposition of the next coal seam 32 feet higher in the sequence. The strata are cut by numerous thrusts and are contorted, folded and broken in a complex manner. The mudstones have been converted into a typical " clod ", i.e. a relatively finegrained rock which breaks continuously into small pieces and is very difficult to support in either a cliff face or underground. The underlying Fox Earth Coal is almost undisturbed. Various lines of argument led to the suggestion that the structures of these strata were due to earthquake disturbance rather than to slumping as usually understood. By reason of the detailed knowledge of the stratigraphy of the Middle Coal Measures of the East Pennine Coalfield it was possible to demonstrate that disturbed strata occur at several other localities on this horizon through the length of the coalfield. At two localities sandstone dykes cut through the underlying coal. The widespread occurrence of these phenomena at exactly the same horizon supports the suggestion that they are due to earthquake disturbance.
Gravity and Magnetic Anomalies in North Wales
Authors: Powell David Williamson , Griffiths Donald Harrison , King Roy Favell 
Published: October 2009

Summary
Bouguer anomalies in North Wales have been calculated from a network of gravity stations in which the standard deviation of a gravity difference is about 0·2 mgl. Magnetic anomalies have been surveyed in part of the area. Rock densities have been measured in the laboratory and in the field.
The depth to the Pre-Cambrian geosynclinal floor in North Wales is thought to influence the gravity anomalies in some areas, but may control the magnetic anomalies more directly. The regional gravity gradients are due to deeper density contrasts, possibly those involved in crustal warping.
At the head of the Vale of Clwyd, 2500 feet of Upper Carboniferous is inferred; farther south, 2000 feet of Trias. The possibility of a Triassic basin under Cardigan Bay is discussed. Structures within the Flint Coalfield are reflected in the gravity anomalies.
The energy of earthquakes
Authors: Gutenberg Beno 
Published: October 2009

Summary

Calculation of the energy released during earthquakes, including all great shocks from 1904 to 1954, indicates that the average annual release of energy in earthquakes is roughly 10
25
ergs. Since this is only about 0–1 per cent of the energy produced by disintegration of radioactive matter in the earth, processes maintained by the generation of heat could furnish the earthquake energy. In each of the three major depth ranges, (a) shallow shocks, depth
h
≤ 60 km., (b) intermediate shocks, 60 <
h
≤300 km., (c) deep shocks,
h
> 300 km., the frequency of earthquakes increases about exponentially with decreasing earthquake magnitude
m
down to at least
m
= 2, and in each the average energy release between 1904 and 1913 was greater than that in later decades. The largest energy calculated for a single shock during the 51 years, about 2 X 10
25
ergs, was found for two shallow shocks. With increasing focal depth h the maximum energy of a single shock decreases to about 6 X 10
23
ergs at h = 650 ± km. and to about 4 X 10
22
at 720 ± km. No deeper earthquakes are known. The rapid decrease in energy release near 700 km. could be caused by flow processes if the apparent coefficient of viscosity decreases to the order of 10
20
poises at a depth of about 700 km.
Seismic Prospecting in the Western Approaches of the English Channel
Authors: Day Alan Arthur , Hill Maurice Neville , Laughton Anthony Seymour , Swallow John Crossley 
Published: October 2009

Summary
On the basis of the measured seismic velocities, the layering found at 25 seismic stations in the area of the Western Approaches of the English Channel is divided into four classes which are respectively correlated with semi-consolidated Cretaceo-Tertiary sediments, the New Red system, the Palaeozoic system, and a metamorphic basement. The last of these appears to form a long, deep trough. The Palaeozoic floor is depressed in a trough of somewhat variable depth, bounded on the north by an outcrop of the metamorphic basement which is possibly a westward extension of the upthrust Lizard-Start metamorphic belt. Contour maps of the layering are produced.
The Boyndie syncline of the Dalradian of the Banffshire Coast
Authors: Sutton John , Watson Janet 
Published: October 2009

Summary
The paper deals with the great fold affecting the Dalradian rocks exposed on the Banffshire coast, for which the name Boyndie syncline is now proposed. It is a large asymmetrical syncline whose axis runs north-north-east and emerges on the coast west of Banff. Its western limb is steeply inclined and, as Read showed, youngs eastward; over short stretches the rocks of this limb are intensely corrugated by subsidiary folds. The eastern limb is, as a whole, very gently inclined and is flexed to form the shallow Turriff syncline. Much of this limb is violently corrugated on a small scale. Variations in the attitude of the axial planes of small folds within the Boyndie syncline are described and discussed. It is suggested that the corrugation of the eastern limb is due to the squeezing out of incompetent beds from the core of the major fold.
The central part of the steep western limb of the syncline has been intensely deformed and boudinage, mullioning and allied processes have led to the formation in this zone of a tectonic melange in which elonaated or lenticular masses of rock are enclosed in a less competent matrix. The axiil plunge of small-scale structures in this zone is very variable and is often steep. Preliminary petrofabric studies show that the preferred orientation of quartz is much stronger here than elsewhere in the fold. An oblique cleavage is imposed on rocks to the east and west of the intensely deformed sector.
The possible significance of the structures seen on the Banffshire coast is discussed and their bearing on current views on the tectonics of North-East Scotland is debated.
A sedimentary study of the Fell Sandstones of the Coquet Valley, Northumberland
Authors: Robson Douglas Arthur 
Published: October 2009

Summary
The Fell sandstones are about 1000 feet thick in the Coquet valley. They form the upper part of the Tuedian, which is the lower division of the Lower Carboniferous in Northumberland. Current-bedding is generally present, and occasionally shows deformation structures. Directions of current-bedding indicate a source lying to the north-east.
The heavy mineral content of the underlying Cementstone Group is distinct from that of the Fell Sandstones. The lower part of the latter, described as the mixed zone, contains a mineral assemblage common to both groups.
The results of mechanical analysis show a marked degree of uniformity of grade-size throughout the Fell Sandstones. Coarser beds occur only very occasionally. Careful sampling from individual units of current-bedding indicates that all parts of a single unit generally yield almost coincident cumulative curves. Adjacent units of current-bedding often differ from one another in grade-size, evidently in response to the varying strengths of tho depositing currents. To the same cause may be ascribed the variations in the percentages of heavy minerals in samples taken from adjacent current-bedded units.
The two great breaks in the history of life
Authors: Watson David Meredith Seares 
Published: October 2009

Summary
Very early in the history of geology it became recognized that past time, so far as the history of life was concerned, fell into three periods: Primary, Secondary and Tertiary. Each contained fossils, easily recognized—trilobites, ammonites and mammals—which as groups characterized the periods, coming in with them, dying out at their ends. When evolution became the accepted explanation of the successive series of animals and plants the existence of “ gaps ” between the faunas of the three periods implied evolutionary events not easily understood, and their nature and significance have often been discussed. Most of such discussions have been based on the history of marine invertebrates, and are inconclusive. Thus some study of the events through their effects on land-living vertebrates throws further light on the phenomenon and its evolutionary significance.
On the trace-fossil
Chondrites
Authors: Simpson Scott 
Published: October 2009

Summary

The problematical fossil
Chondrites
, well known from the Flysch of the Alps, Carpathians and Apennines, and from the Lias of Germany, is shown to be common in various Palaeozoic formations of the British Isles and also in the English Lias. The varying forms taken by the fossil are described and explained and shown to be primarily the result of different modes of preservation and not of taxonomic significance. A consideration of the different modes of preservation, as well as of the morphology of the fossil, permits its interpretation as a trace-fossil resulting from the driving of a system of branching tunnels in the sea-bed sediment. A new reconstruction of the fossil has been made. It is tentatively explained as the product of a sipunculoid worm feeding on sediment by means of its extensible proboscis. Various implications of the mode of occurrence of the fossil in particular circumstances are considered.
The Dawros peridotite, Connemara, Eire
Authors: Rothstein, Andrew T. V. 
Published: October 2009

Summary
The Dawros peridotites are characterized by a strong banding and evidence of thermal metamorphism exists in the enclosing schists. The banding arises from a rhythmic crystal accumulation ranging through a sequence of dunites and pyroxenites in which the assemblage olivine and orthopyroxene at one extreme passes into the assemblage olivine, clinopyroxene and subordinate orthopyroxene at the other.
Felspar is absent. There is evidence of gravity stratification and the action of magmatic currents in the chrome—spinel horizon which occurs at the transition between the two principal mineral groups.
The textures vary from primary igneous to secondary metamorphic, the primary minerals having frequently recrystallized under conditions of high-temperature dynamic metamorphism. There is also evidence in the country rocks of a period of deformation subsequent to the thermal metamorphism.
The pyroxenes show a primary variation within the solid solution series, of an iron enrichment over a restricted magnesium-rich range; the orthopyroxenes lie in the onstatite-bronzite series and the clinopyroxenes within a similar diopsidic range. There occurs among the recrystallized rocks a hypersthene-pyroxenite of charnockitic type.
The conclusions drawn are that the Dawros mass is a peridotite formed as a deep-soatod magmatic crystal accumulate, subsequently dynamically metamorphosed, possibly while being emplaced into higher levels of the earth's crust, and later undergoing serpent inization.
The stratigraphy and structure of part of the Kintail district of southern Ross-shire : Its relation to the Northern Highlands
Authors: Clifford Tom Neville 
Published: October 2009

Summary
The portion of southern Ross-shire dealt with in this paper lies between the two recently redescribed districts of Fannich Forest (Sutton & Watson 1954) on the north, and Morar, Inverness-shire (Kennedy 1955), on the south. This paper provides the first detailed geological survey of the area.
The district is composed essentially of crystalline schists and gneisses of the Lewisian Gneiss and Moine Series disposed in north-easterly and north-north-easterly trending major isoclinal folds. Within the most important of these, the Sgùrr an Airgid syncline, the following structural succession has been established :—
The upper element is regarded as composed of exotic representatives of the lower element repeated at higher levels by thrusting ; in view of the disposition of this element as a structural outlier it is termed the Kintail klippe. The question of a root-zone is discussed.
The major post-Moinian structural events in southern Ross-shire have been recognized as thrusting and the emplacement of the Kintail nappe, folding along NE.—SW. (Caledonide) axes and the development of WNW.—ESE. trending " crossfolds." These phases were followed by post-metamorphic faulting as exemplified in the Strathconon fault plexus. The regional implications of the now map area are discussed.
The geological interpretation of a gravity survey of the Alston Block and the Durham Coalfield
Authors: Bott Martin Harold Phillips , Masson-Smith David 
Published: October 2009

Summary
Problems of the deep structure of the Alston Block and the Durham Coalfield are outlined in relation to previous geophysical work. The gravity survey planned as the most expedient approach to these problems is briefly described. The results of a density survey undertaken in conjunction with the gravity survey are stated.
The main feature of the gravity survey is a large negative anomaly over the Alston Block. The earlier conclusion, that it is caused by an unexposed granite, is upheld by the detailed physical and geological interpretation. The postulated granite approaches closest to the surface in five bosses, some of which almost certainly reach within 5000 feet of the surface. The shape of the gravity anomalies bears remarkable resemblance to the zones of mineralization and the volatile content of the coal seams, and for these reasons a post-Carboniferous age seems likely. Possible modes of origin of the postulated granite are discussed.
The northward decrease of anomaly across the Stublick fault system is caused by fairly rapid thickening of the Lower Carboniferous succession, which continues eastwards across the line of the Ninety Fathom Dyke. A southward Bouguer decrease- across the Butterknowle fault is similarly interpreted as a southward thickening of Lower Carboniferous rocks. The internal structural features of the Alston Block are interpreted in relation to the assumed granite below.
A study of the background Bouguer anomaly suggests a North Pennine crustal mass deficiency in addition to the granite. It is considered that the granite mass deficiency, if accompanied by an additional crustal deficiency, could account iso-statically for the present North Pennine uplift, and for the general stability since the Lower Carboniferous.
Interpretation of a vertical field magnetic survey in North-East England
Authors: Bott Martin Harold Phillips , Masson-Smith David 
Published: October 2009

Summary
A vertical field magnetic survey of Durham and South Northumberland supplements the gravity survey described in the previous paper. The field survey and its reduction are described and some of the problems of interpretation are mentioned.
A negative magnetic anomaly over the Alston Block is interpreted as another manifestation of a concealed granite under Weardale. Similar anomalies occur over exposed mineralized granites elsewhere, and arise from granite with low polarization existing in country rocks with higher polarization. The magnetic minima are displaced to the south-east of the corresponding gravity minima, and it is thought that this is caused by permanent polarization directed westwards in the country rocks. A violent positive anomaly lies immediately to the north at Blanchland and is tentatively interpreted as a marginal feature of the assumed granite.
A magnetic anomaly of Caledonian strike in Northumberland probably marks the southern limit of low-polarization basement rocks. This may well represent the south-eastern limit of the sub-Carboniferous outcrop of the Southern Uplands Upper Ordovician and Silurian rocks.
The Middle Lias of the Dorset coast
Authors: Howarth Michael Kingsley 
Published: October 2009

Summary

The two zones of the Middle Lias of the Dorset coast are remarkably different. The
spinatum
Zone at the top has a maximum thickness of only two feef, consisting of ferruginous sandstones or limestones containing species of
Pleuroceras
. The
margaritatus
Zone is more than two hundred times thick, consisting of loams, clays and sands, wit hard sandstone and limestone bands, containing species of
Amaltheus
and
Amauroceras
.

In the palaeontological section of the paper, remarks on the amaltheid ammonites are confined to their stratigraphical distribution, and more detailed treatment is given to representatives of
Metacymbites, Dactylioceras
, and the Middle Liassic hildoceratids
Leptaleoceras
and
Paltarpites
.

Finally, a comparison is made with the stratigraphy and ammonite faunas of the Middle Lias on the Yorkshire coast, and the conclusion is drawn that differences between the two areas were greater in
spinatum
Zone times than in
margaritatus
Zone times.