bluuebunny/crossref_metadata_2025 huggingface dataset:
Linear sole markings in Pleistocene till
Authors: Westgate J. A.
Published: May 2009

Current-produced sole markings are not uncommon in the Pleistocene continental till deposits of Alberta, Canada. Groove, striation and prod moulds have all been recognized, characteristically occurring in close association on the undersurface of the till beds. These sedimentary structures provide a rapid means by which local ice-flow directions may be determined.
Note on radiometric age determination of samples of peat and wood from tin-bearing Quaternary deposits at Sungei Besi Tin Mines, Kuala Lumpur, Selangor, Malaysia
Authors: Haile N. S. , Ayob Mohammad Bin
Published: May 2009

A radiometric age determination on wood in tin-bearing alluvium from Selangor gives a result of about 36,000 years B.P. This is consistent with the view that the deposits formed during a period of rejuvenation of river systems during the Pleistocene. Meagre palynological evidence indicates the deposit is late Pliocene or younger.
A Pre-Cambrian Glass from St. Alexis-des-Monts, Quebec
Authors: Philpotts A. R. , Miller J. A.
Published: May 2009

The Pre-Cambrian rocks north of Three Rivers, Quebec, are cut by a major fault in which glassy pseudotachylites have been developed. The glass, which is dark brown in thin section, has a specific gravity of 2.76 and a refractive index of 1.567. It has a similarcomposition to the quartz monzonite in which it occurs. Absolute dating by the potassium-argon method indicates that the glass is 975 million years old. The persistence of thisglass indicates how sluggish devitrification can be when the environment is cool and dry.
A second specimen ofOsculocystisPaul 1967
Authors: Paul C. R. C.
Published: May 2009

A second specimen ofOsculocystisconfirms that the genus occurs in the Upper Llandovery (Purple Shales) near Buildwas, Shropshire and adds information on morphology. The subvective system consists of a single long brachiole; the stem lacks a root structure. The mouth, gonopore and hydropore are described and the three pectinirhombs B2:IL2, L2:R1 and L4:R3 are confirmed.
The origin of some transverse sand patches in the Celtic Sea
Authors: Kenyon N. H.
Published: May 2009

Transverse sand bodies of a new type from the continental shelf are commonly 2m high, 500m long and crescentic in plan view. They are believed to be transported at the present day by weak tidal currents (approximately 1 knot peak velocity near the surface) associated with wave induced oscillatory water movements of similar strength, rather than being formed near the shores at times of lower sea level.
Cone-sheets as a mechanism of uplift
Authors: Le Bas M. J.
Published: May 2009

By the study of dilation associated with cone-sheet emplacement and the deformation of the basal Carboniferous unconformity at the Irish Tertiary igneous centre of Carlingford, it is shown that cone-sheets are capable of producing considerable uplift. This process is also the cause of the steep-sided domes which occur at some carbonatitic centres in Kenya.
Feldspathic vent agglomerates at Bukusu, Uganda—a reinterpretation
Authors: Baldock J. W.
Published: May 2009

Feldspathic agglomerates and related tuff-like rocks occurring at the Bukusu carbonatite complex were long thought to have been deposited as pyroclastics during a later (Elgon) period of volcanism. Evidence is presented for a reinterpretation of these rocks as vent agglomerates and tuffisites emplaced in the central diatreme of this large, pre-Elgon, complex.
The origin of some collapse structures in the Canary Islands
Authors: Ridley W. I.
Published: May 2009

Three large collapse structures, two bounded by straight, vertical escarpments and curved head regions, are described from Tenerife. Similar structures appear to exist on Hierro and La Palma. Their size precludes landsliding as the dominant force in their formation, although it may have played a minor role in modifying the bounding walls. It is suggested that these structures are true volcanic collapse features developed by a ‘trap-door’ type of mechanism. The lack of classical caldera shapes appears to be a reflection of a lack of well-defined central volcanism on any of the islands, the collapses probably resulting from migration of magma away from the central rift-zones towards the flanks of the islands.
Monograptus priodon (Bronn) from the Macduff Group (Upper Dalradian) of Banffshire, Scotland
Authors: Skevington D.
Published: May 2009

Two incomplete graptolite rhabdosomes in the Hugh Miller Collection (Royal Scottish Museum) are referable to Monograptus priodon (Bronn). The specimens were obtained from the Macduff Group, the youngest member of the Upper Dalradian succession in Banffshire (Read, 1923). This occurrence extends the upper stratigraphical range of the Dalradian Series into, at least, the Lower Silurian and possibly into the lowermost part of the Upper Silurian.
Pleistocene superficial deposits, Balcombe area, central Weald
Authors: Piper D. J. W.
Published: May 2009

Pleistocene silty mudflow deposits mantle much of the valley sides and floors of the Balcombe area of the central Weald. Boulder deposits at the foot of cliffs formed of resistant bedrock sandstones are also of Pleistocene age. One well sorted sand from a gentle valley side shows surface grain textures under the scanning electron microscope indicative of wind action. The superficial deposits formed under periglacial conditions, and their distribution indicates most of the landforms are relict Pleistocene features.
Metamorphosed rugose corals in Devonian Limestone, at Calcium, North Queensland, Australia
Authors: Morgan W. R. , Perrott I. H. , Petherbridge R. T.
Published: May 2009

Contact metamorphosed rugose corals now consist of sub-radiate to sub-parallel fibres of wollastonite. It is considered that they result from the recrystallization of corallites that were partly silicified during diagenesis.
Washout Structures in the Dalradian near Kentallen, Argyll
Authors: Bowes D. R. , Wright A. E.
Published: May 2009

The occurrence of numerous washout structures in the Appin Quartzite is recorded and the criteria by which they are recognized discussed. It is concluded that these structures are reliable for the determination of the way-up of beds and that their association with current and graded bedding indicates a turbid deltaic environment of sedimentation.
Turbidity Current at Kadavu Passage, Fiji
Authors: Houtz R. E. , Wellman H. W.
Published: May 2009

The 1953 earthquake at Suva in the Fiji Islands caused submarine subsidence at the outer edge of the coral reef near Suva. Sixty miles of the cable from Suva to Norfolk Island was either buried or shifted about 2 miles from its original position. The damaged cable followed close to the centre of a submarine valley that extends out from the coral reef near Suva. A length of cable recovered from the ocean bottom 40 miles from Suva is damaged in a way that indicates that it was eroded while lying partly buried in sediments and was then torn up and twisted. A wire hawser found attached to the cable had been cleaned by sandblasting. It is inferred that the cable was damaged by a turbidity current that originated at the submarine subsidence, that the current had a velocity of at least 10 miles an hour, and that it travelled for at least 70 miles.
Clay Mineralogy of Selected Clays from the English Wealden
Authors: Tank R. W.
Published: May 2009

X-ray analyses of selected samples from the argillaceous subdivisions of the English Wealden indicate that illite, kaolinite, and mixed-layer structures are present in variable amounts. The clay mineral assemblage is thought to reflect parent material, weathering conditions in the source area, and possibly some degrading of the illite structure by the action of active waters in the depositional environment. The specific clay minerals are tentatively correlated with the palaeogeographical framework proposed by Allen (1954). It is suggested that the kaolinite was derived mainly from the Palaeozoic uplands, and the bulk of the illite and mixed-layer structures from the marginal Jurassic lowland.
Sedimentary Structures in the Keuper Marl (Upper Triassic)
Authors: Klein George DeVries
Published: May 2009

Combinations of sedimentary structures in the lacustrine Keuper Marl are segregated bathymetrically. Beds deposited below lacustrine wave base are characterized by even bedding, rhythmic lamination, disturbed stratification, graded bedding, load casts, “pull-apart” structures, and oscillation ripple marks. Lacustrine beds deposited above wave base contain even bedding, rhythmic lamination, oscillation and interference ripple marks, current lineation, rib-and-furrow structure, groove casts, mudcracks, and raindrop imprints.

A marine unit in the Keuper Marl is characterized by even bedding, flat-topped oscillation ripple marks, and air-heave structures.

Comparison with sedimentary structures of other known lacustrine deposits suggests that the combination of structures in the non-marine Keuper Marl is diagnostic of lacustrine deposits. Recognition of such combinations of sedimentary structures should aid in interpreting the origin of continental sequences.
The Geology of the Katmaian Volcanics of the Upper Oramutia Valley, Kenya
Authors: Bristow C. M.
Published: May 2009

The Oramutia volcanics consist of a group of ignimbrites overlain by pumice tuffs, which lie in a fault formed valley on the eastern flank of the main Kenya rift valley. The presence of a dyke of ignimbrite suggests that the “claystone ” ignimbrite of this area was erupted from fissures. A similar explanation probably applies to the pumice tuffs. These volcanics are therefore the product of Katmaian type eruptions.
The Gneisses of the Bartica Assemblage, British Guiana
Authors: Cannon R. T.
Published: May 2009

The results of an examination of one quarry within the gneisses of the Bartica Assemblage are described and the validity of these results throughout the whole of the Bartica Assemblage is discussed. The foliation and banding of the gneisses at Kereti Quarry are mainly the results of tectonism; concomitant metamorphism within the Amphibolite Facies was succeeded by a two-phase metasomatism involving successive additions of Na and K. These results appear valid throughout the Bartica Assemblage and it is further suggested that the main rock type distribution in the Bartica Assemblage is also controlled by tectonism.
Shape and size trends for sand waves in a depositional zone of the North Sea
Authors: Stride A. H.
Published: May 2009

A continuous profile of 430 large sand waves shows a progressive decrease in height (with some increasing crest separation) in their inferred migration direction, as well as showing the changing effectiveness of the ebb and flood tidal currents to move sand. The height of these and other sand waves around the British Isles is virtually unrelated to the depth of the sea, contrary to what has been suggested elsewhere. However, most sand waves occur on the continental shelf broadly because it is there that the currents reach a suitable range of speeds and sufficient sand is available at the present time.
A Miniature “Dyke” Echelon
Authors: Gilliland William N.
Published: May 2009

A specimen of shale containing an echelon of quartz-filled vertical tension fractures which merge “at depth” with a single filled fissure dipping 65 degrees confirms, in general, E. M. Anderson's interpretation of dyke echelons. Also illustrated are a change in manner of stress relief and an upward diminution of strain.
A mega-porphyritic dolerite on Long Island, Seychelles Archipelago
Authors: Frankel J. J.
Published: May 2009

A dolerite intrusion on Long Island, Seychelles contains exceptionally large plagioclase (labradorite) phenocrysts essentially unzoned, set in a doleritic groundmass. Many of the mega-phenocrysts have a dark redbrown interior.

In the groundmass, zoned plagioclase is in a doleritic texture with a slightly titaniferous ferro-augite that has been almost completely replaced by an actinolite uralite.

The mega-phenocrysts are considered to have crystallized slowly at depth and concentrated locally in a chamber of basaltic magma. The portion of magma containing these plagioclase crystals was later injected to higher levels as dykes. Although emplaced in a granitic (continental) environment, the intrusion has oceanic basalt affinities, and in chemical composition resembles high alumina basalts.
On Hemitrypa hibernica M'Coy
Authors: Miller T. G.
Published: May 2009

M'Coy's type material of Hemitrypa hibernica is re-described. The relation between the main fenestelloid structure and the hexagon-mesh superstructure, and the function of the latter, are discussed.
The Evolution of Gryphaea
Authors: Philip G. M.
Published: May 2009

The coiling of the Liassic oyster Gryphaea is discussed and the assessment of tightness of coiling investigated. Hence Hallam's (1960a, b) statistical work on Gryphaea is interpreted and from his original measurements a highly significant increase in thetightness of coiling is demonstrated in the Gryphaeas of the higher Sinemurian horizons of Britain. The presence of a strong natural selection pressure favourable to more tightly coiled individuals of the communities is indicated, and the nature of the lineage discussed. It is suggested that recent criticisms of Trueman's work lack foundation.
The Composition of Marls and Limestones in the Great Oolite Series of Oxfordshire
Authors: Sugden W. , McKerrow W. S.
Published: May 2009

Analyses of eighteen samples from Jurassic marls and limestones show a large, continuous range in carbonate-clay composition. The significance of the carbonate/clay ratio is discussed, and it is show that rapid lateral and vertical transitions from marl to limestone may either reflect major changes in composition or represent only small shifts (across a critical value: 4) in the carbonate/clay ratio. The term “marl” is defined.
The Highland Border Ridge of North-east Ireland
Authors: Sanderson D. J.
Published: May 2009

The Highland Border Ridge is a present day positive physiographic element whose activity can be traced back to Devonian time. A change from a distant Lower Dalradian to a nearby Middle and Upper Dalradian source area during Lower Old Red Sandstone times reflects the initial development of the ridge. A model for ridge uplift is outlined and some of its implications discussed.
Metamorphism of Caledonian Metadolerites in North-west County Mayo, Ireland
Authors: Max M. D.
Published: May 2009

Caledonian dolerite dykes in northwest County Mayo, Ireland, are differentially metamorphosed with volumes of largely unmetamorphosed dolerite grading into marginal amphibole schists with no preserved igneous textures. Deformation controlled the extent of the metamorphism. The lack of a significant differential strain in the volumes of preserved igneous rock is considered to be the cause of the preservation.
Significance of lineation and minor folds near major thrust faults in the southern Appalachians and the British and Norwegian Caledonides
Authors: Bryant Bruce , Reed John C.
Published: May 2009

The Blue Ridge thrust sheet is one of the principal thrust masses of metamorphic rocks in the southern Appalachians. A broad zone of sheared and retrogressively metamorphosed rocks near the sole of the thrust sheet around the Grandfather Mountain window displays numerous small tight or isoclinal folds having axes subparallel to an intense penetrative cataclasticalineation and axial planes parallel to foliation in the thrust sheet. These folds seem to have formed by tightening, flattening, and passive rotation of earlier more open folds originally formed perpendicular to the direction of transport. The style and orientation of these folds closely resemble those of analogous structures in thrust masses of crystalline rocks in the Caledonian orogenic belt in Scotland and Norway, suggesting that the structures of both regions may have similar origins.
An Upper Llandovery limestone overlying Hollybush Sandstone (Cambrian) in Hollybush Quarry, Malvern Hills
Authors: Jones R. K. , Brooks M. , Bassett M. G. , Austin R. L. , Aldridge R. J.
Published: May 2009

New exposures of Upper Llandovery and Cambrian strata are described from the southern Malvern Hills. The rocks occur in a small faulted outlier between Midsummer and Hollybush Hills, within the main Pre-Cambrian outcrop. The Cambrian is represented by a thin succession of Malvern Quartzite and Hollybush Sandstone and is overlain by an Upper Llandovery limestone with a basal conglomerate containing rounded pebbles of Hollybush Sandstone. The new exposures weaken the case for a major post-Llandoverian fault at the western boundary of the local Pre-Cambrian outcrop, but provide further evidence of an important phase of pre-Llandoverian tectonism in the Malvern area.

Faunas of brachiopods, graptolites and conodonts from the Llandoverian limestone allow a correlation with the C5 substage of the shelly sequence, the griestoniensis graptolite zone and a position near the boundary of the celloni and amorphognathoides conodont zones.
The Petrology of a Teschenite Sill at Landywood, Staffordshire
Authors: Barton M. E.
Published: May 2009

Borehole cores have been obtained of a basic igneous sill at Landywood, near Cannock, Staffordshire. This intrusion consists mainly of microteschenite with a zone of teschenite in the top half of the sill. Later parts of the parental magma of this intrusion were dryer and crystallized to give crinanite and analcite olivine dolerite. These later parts were not intruded in sufficient quantities to spread through the whole of the sill and were restricted to the vicinity of the feeding pipe. Extensive secondary replacement of plagioclase by chlorite and of pyroxene by carbonate occurs in the teschenitic parts of the sill and is ascribed to the action of water and carbon dioxide derived from the magma.
Volcanic and Associated Rocks in the Coal Measures of Colston Bassett (South) Borehole, Nottinghamshire
Authors: Sabine P. A.
Published: May 2009

The BP Exploration Company's Colston Bassett (South) No. 1 Borehole, Nottinghamshire, entered Coal Measures at 1,134 feet. These persisted for 901 feet, when massive tuffs were encountered which were 679 feet thick and overlay Millstone Grit. The tuff is composed of amygdaloidal glass, devitrified to a montmorillonite, and is rich in analcime. In a nearby borehole, no tuffs were encountered and the Coal Measures were 1,784 feet thick. It seems that at Colston Bassett (South) the lowest Coal Measures sediments are represented by the tuff, which is non-displacive and was perhaps a cone against which the later sediments were deposited.
A Note on the Crag in Norfolk
Authors: Downing R. A.
Published: May 2009

In East Norfolk, boreholes have revealed the presence of a northern and a southern clay bed in the Crag. These lie at different horizons and have been linked to clay exposures previously correlated with the Chillesford Beds of Suffolk. It is concluded that a clay facies is developed at two main horizons in the Crag in Norfolk.
A Note on Some Acid Breccias in the Kilchrist Vent, Skye
Authors: Ray P. S.
Published: May 2009

Three acid breccia-bodies which are emplaced within the basaltic agglomerate of the Kilchrist vent of Tertiary age are described. They are considered to be of pyroclastic origin. Petrographic evidence which relates to the probable mechanism of emplacement of the breccias is discussed.
Stratigraphy and Origin of the Cork Red Marble
Authors: Nevill W. E.
Published: May 2009

The Cork Red Marble is a coarse, graded but poorly sorted, re-sedimented lime-conglomerate, of Caninian age. It occupies a central position within 4,000 feet of Waulsortian limestones. The pebble content of “porcellanous” calcite mudstone—not in reef facies—is set in a matrix of red clay. Mixed biofacies are represented, because of reworking: fragmented large molluscs, indicative of a nourishing reef habitat, contrast forcibly with a mollusc spat-ostracod assemblage as found in the pebbles. The conglomerate was probably formed when back-reef sediments, which included red clay, were elevated and then redeposited, possibly by turbidity currents
The Petrogenetic Model, an Extension of Bowen's Petrogenetic Grid
Authors: Wyllie Peter J.
Published: May 2009

Bowen's petrogenetic grid is a PT projection containing univariant curves for decarbonation, dehydration, and solid-solid reactions, with vapour pressure (Pf) equal to total pressure (Ps). Analysis of experimental data in the system MgO–CO2–H2O leads to an expansion of this grid. Three of the important variables in metamorphism when Pf = Ps are P, T, and variation of the pore fluid composition between H2O and CO2. These can be illustrated in a three-dimensional petrogenetic model; one face is a PT plane for reactions occurring with pure H2O, and the opposite face is a similar plane for reactions with pure CO2; these are separated by an axis for pore fluid composition varying between H2O and CO2. Superposition of the PT faces of the model provides the petrogenetic grid. The reactions within the model are represented by divariant surfaces, which may meet along univariant lines. For dissociation reactions, the surfaces curve towards lower temperatures as the proportion of non-reacting volatile increases, and solid-solid reaction surfaces are parallel to the vapour composition axis and perpendicular to the PT axes. The relative temperatures of reactions and the lines of intersections of the surfaces can be illustrated in isobaric sections. Isobaric sections are used to illustrate reactions proceeding at constant pressure with (1) pore fluid composition remaining constant during the reaction, with temperature increasing (2) pore fluid composition changing during the reaction, with temperature increasing, and (3) pore fluid changing composition at constant temperature. The petrogenetic model provides a convenient framework for a wide range of experimental data.
On the Supposed Evolution of Gryphaea in the Lias
Authors: Hallam A.
Published: May 2009

A re-examination of Hettangian and Lower Sinemurian oysters has led to the rejection of Trueman's hypothesis on the evolution of Liostrea into Gryphaea. Gryphaea assemblages from two horizons in different parts of Britain have been subjected to bivariate and size frequency analysis. The only detectable difference is a slight size increase up the succession. No “gryphaeoid” trend is discernible in Liostrea up the Hettangian succession and the change to Gryphaea is in consequence abrupt. All the oysters of Trueman's series are referred to what are considered to be two different Linnaean species.
The Mechanics of Oblique Slip Faulting
Authors: Bott M. H. P.
Published: May 2009

The various mechanisms which could cause oblique slip faulting are briefly reviewed. It is thought that such faulting may frequently arise from the existence of preferred planes of fracture within the rocks. The dynamics of this mechanism is studied in some detail and an expression is obtained for the first direction of slip within the plane under the influence of a general stress system of given orientation it is found that the initial slip may occur in any possible direction within the plane, the direction depending on the relative values of the three principle pressures. The theory suggests that when a pre-existing fault is subjected to a reorientated stress system (typical or rotated) the movement after fracture will usually be oblique. In conclusion, the general implications of the theory are discussed.
Chess-Board Albite from New Brunswick, Canada
Authors: Starkey John
Published: May 2009

Chess-board albite is described and theories on its origin outlined. A new occurrence from New Brunswick, Canada, is noted and certain features of the chess-board albite, discussed which fit the theory that it results from two processes, namely metasomatism of potash feldspar to soda feldspar, and deformation. This hypothesis is applied to British localities.
Culm Stratigraphy and the Age of the Main Orogenic Phase in Devon and Cornwall
Authors: Simpson Scott
Published: May 2009

The major stratigraphic divisions of the Carboniferous rocks of Devon and Cornwall are characterized and new terms suggested to replace those of W. A. E. Ussher. It is shown that there is in South Devon and Cornwall a major unconformity separating an uncleaved group of post-orogenic Carboniferous strata (Ugbrooke Group) from underlying Devonian and Carboniferous with slaty cleavage. It is argued that the Ugbrooke Group is younger than any strata hitherto thought to be present in the Carboniferous of South-West England, and that the major orogeny is either Malvernian or Asturic in age.
Some supposed ‘raised beach’ deposits at Corran, Loch Linnhe, and Loch Etive
Authors: McCann S. B.
Published: May 2009

Two large gravel deposits, at Corran on Loch Linnhe, Inverness-shire, and at the entrance to Loch Etive, Argyll, are described, and it is considered that they are fluvio-glacial fans, marking a contemporaneous halt in the retreat of the valley glaciers which occupied the sites of these two lochs. Orientation analysis of the pebbles in the Corran deposit supports this conclusion. Similar analysis on gravels along the northern shore of Loch Etive indicates that they are not raised beaches, but were deposited in lakes held up by the glacier which deposited the Loch Etive fan.
The Age and Relationships of the Cornbrook Sandstone
Authors: Jones D. G. , Owen T. R.
Published: May 2009

The Cornbrook Sandstone of Titterstone Clee Hill has plants of Westphalian (Middle Coal Measures) age. It is thus probably a correlative of the lower Kinlet Group of the Forest of Wyre. The base is unconformable to the Old Red Sandstone and Carboniferous Limestone while the top is apparently conformable with Productive Coal Measures of the Sweet Coal Group, also of Middle Coal Measures age.
Rock Magnetism Applied to Some Geological Problems
Authors: Blundell D. J.
Published: May 2009

Recent studies concerned with the application of rock magnetism to several geological problems serve to illustrate the scope of the methods at present available. Rock magnetism can usefully be applied to determine the age of a rock or to correlate it with some other. It may be used in studying the structural history of a formation or the thermal history of a rock. The examples cited deal with igneous rocks in Britain, but the methods also apply to some sediments, and possibly to metamorphic rocks.

It is stressed that rock magnetism can be applied quite independently of any theory concerning the earth's field. It is necessary only to establish whether the magnetism measured in the laboratory is a true record of that acquired when the rock formed, or at some other known time in its history.
A Formation of Marekanite at El Fiscal, Guatemala
Authors: Ljunggren Pontus
Published: May 2009

An outcrop of obsidian pebbles in a grey volcanic rock was investigated in the field and subsequently examined in the laboratory by means of optical, X-ray, and D.T.A. methods. The results show that the grey rock arose from obsidian through a micro-cracking, causing a formation of marekanite balls (massive obsidian) surrounded by a very brittle grey rock (micro-cracked but completely unaltered volcanic glass).
Shear Failure of Anistropic Rocks
Authors: Jaeger J. C.
Published: May 2009

The two-dimensional theory of two simple generalizations of the Coulomb-Navier criterion for shear failure is developed. The first of these refers to a material with a single plane of weakness which has a different shear strength and coefficient of internal friction from the remainder of the material. In this case it is shown that failure may take place, according to circumstances, either in the plane of weakness or in planes cutting across it. The second criterion refers to a layered material whose shear strength varies continuously from a maximum in one direction to a minimum in the perpendicular direction. In this case it appears that, instead of the two directions of failure possible for an isotropic material, there is only one possible plane of failure which lies between the plane of minimum shear strength and the nearest to it of the two Coulomb-Navier planes. Numerical results are given for the case of uniaxial compression and experimental results are shown to be in reasonable agreement with them.
Inclined Granitic Pipes in the Diorites of Guernsey
Authors: Elwell R. W. D. , Skelhorn R. R. , Drysdall A. R.
Published: May 2009

Pipe-like bodies, of granitic composition, occur in certain meladiorities in Guernsey. Their average diameter is 3 inches, and they are all similarly inclined. Some connect downwards with an acid vein system; others with a discontinuous acid layer. It is considered that the pipes were formed before the meladiorite host rocks had solidified, and that their inclination was the result of relative movement between the rocks above and below.
A Fine Air-Heave Structure from the Old Red Sandstone of Lanarkshire, Scotland
Authors: Rolfe W. D. Ian
Published: May 2009

Air-heave structures have previously been described from marine lagoonal deposits, both from present day and ancient sediments. This paper records the find of such structures in playa sediments from the Scottish Old Red—perhaps the first record of such structures from non-marine sediments in the geological column. It is suggested that the structures were formed on the beaches of “Lake Caledonia”, “during a storm, seich, or a heavy rainfall”.
A Garnet-Hornblende-Pyroxene Rock from Glenelg, Inverness-shire
Authors: ÓHara M. J.
Published: May 2009

A garnet-hornblende-two pyroxene rock from Glenelg is described. It is assigned to the eclogite facies by virture of its density, mineral composition, and associations. Its chemical composition is that of a picrite-basalt. Comparison with other garnet-pyroxene assemblages suggests that there are no clear differences between the partition of major and minor elements in these minerals at the eclogite and granulite facies of metamorphism. A diagram to represent parageneses in basic and ultrabasic rocks of the eclogite facies is presented, and points of interest discussed.
Nomenclatural Problems in the Mesozoic Rhynchonelloidea
Authors: Ager D. V.
Published: May 2009

Eight nomenclatural problems connected with Mesozoic brachio-pods of the suborder Rhynchonelloidea are discussed and solutions suggested. A new genus is proposed related to Halorella and a new name is given to a species of Norella
Intra-Stratal Flow and Convolute Folding
Authors: Williams Emyr
Published: May 2009

The property of liquefaction of certain confined, water-logged, unconsolidated sedimentary layers is considered to play an important part in the development of much of convolute folding. Lateral intrastratal laminar flow of liquefied beds, according to flow patterns mainly determined by the distribution of parts of the layers that have remained solid, appears to account satisfactorily for internal folding. Although intra-stratal flow, which can result from a number of causes, may considerably deform the stratification planes of a liquefied layer, there is neither lateral shortening nor a notable change in the thickness of the bed.
A Note on the Disposition of Fold Axes in the Silurian Strata around the Newry Granodiorite
Authors: Anderson T. B. , Bates D. E. B. , Hamilton R. S.
Published: May 2009

An area of high, north-eastward plunge of b-axes has been mapped in Silurian greywackes around the mouth of Strangford Lough, N. Ireland. Reconnaisance over a wider area to the south-west is consistent with the hypothesis that this steep plunge is due to the upward push exerted during the emplacement of the Newry Granodiorite. A near surface extension of the intrusion towards the east-north-east is inferred.
The Laig Gorge Beds, Isle of Eigg
Authors: Hudson J. D.
Published: May 2009

Some rocks exposed near Laig Farm, Isle of Eigg, have previously been referred to the Upper Oxfordian. In this paper their age is shown by foraminifera to be Upper Cretaceous, their petrology described and their stratigraphical significance discussed. Evidence is presented that the supposed unconformity below the Lower Corallian of North-West Scotland does not exist.
Origin of Convoluted Laminae
Authors: Sanders John E
Published: May 2009

Comparison of streaked-out “ripples” formed by the drag effects of a current passing over a watery, yet cohesive sediment bottom with convoluted laminae formed within beds of fine-grained sandstone suggests a common origin. Application of Bagnold's recent discoveries on the behaviour of cohesionless sediment in flowing fluids to the problem results in a modification of Kuenen's hypothesis of origin of the convolutions. According to the new interpretation, convolutions arise when formerly cohesionless sand grains become cohesive after deposition and respond to increased shearing due to higher current velocity by a décollementtype of adjustment with the plane or planes of adjustment located within, or in some cases at or below the base of the growing sandstone bed. Convolute “anticlines” in cohesive sand are thought to serve the same function as that played by current ripple-marks in cohesionless sand, i.e., they create additional bottom relief in order to increase the drag and restore equilibrium to the added shearing stress imposed by the current that cannot be counterbalanced by grain-to-grain encounters.
Metamorphism of the Jurassic Rocks of Glas Bheinn Bheag, near Dunan, Isle of Skye
Authors: Smith Shelagh M.
Published: May 2009

A succession of Jurassic sediments is shown to have been metamorphosed in contact with a Tertiary microgranite. The meta-morphic features of the three main lithological groups of the sediments are described and the conclusion is reached that in addition to simple thermal metamorphism, which is apparent in most of the rocks, the rocks nearest the microgranite have been permeated by aqueous fluids containing K2O, Na2O, MgO, FeO and Fe2O3.
Corundum in Biotite-Sillimanite Gneiss From near Polgahawela, Ceylon
Authors: Cooray P. G. , Kumarapeli P. S.
Published: May 2009

Idiomorphic, pale blue corundum crystals (S.G. =4·02, n0=1·770 ± 0·002) up to one inch long occur as porphyroblasts in a finegrained biotite-sillimanite gneiss cut by pegmatite veins at Gangoda, 5½ miles south of Polgahawela. The field relations and petrography of the corundum-bearing rocks are described briefly. The corundum is thought to have crystallized by metamorphic differentiation in alumina-rich silica-poor bands in a semipelitic gneiss.
The Distribution of some Elements across the Contacts of Four Xenoliths
Authors: Farrand M. G.
Published: May 2009

Two basic xenoliths were taken from the Shap adamellite and two from the Glen Fyne porphyritic granodiorite. Each specimen was divided into the three parts; margin and core of the xenolith and the surrounding host rock. Porphyritic alkali feldspar and sphene were separated from each part and the rocks and minerals were analysed for trace elements and for Na and K. Four specimens of the assumed parent rocks of the xenoliths were also analysed. The results indicate that the two host rocks are similar in trace element content, that equilibrium between minerals in host rock and xenoliths extends to their trace element content and that late stage magmatic fractions may have played a part in the alteration of the xenoliths.
Co-Existing Pyroxenes in Metamorphic Rocks
Authors: O'Hara M. J.
Published: May 2009

Chemical and optical data for eighteen granulite facies pyroxene pairs are compared. Compositions and tie-line trends derived from optical data are shown to be unreliable and it is recommended that no attempt be made to subdivide the granulite facies on the basis of optically derived tie-lines.
Post-Intrusion Deformation of a Dyke Swarm, Awatere Valley, New Zealand
Authors: Challis Gwyneth A.
Published: May 2009

The only known regional dyke swarm in New Zealand is described. Dykes are 1·5–2 feet thick and have been intruded vertically into unconsolidated Cretaceous sediments. The present attitude of dykes is found to be affected by compaction of these sediments and by regional folding and bedding-plane slip. A rough measure of total compaction is obtained.
Preferred Orientation of Nepheline in Deformed Nepheline Syenite Gneisses from Sørøy, Northern Norway
Authors: Sturt Brian A.
Published: May 2009

Evidence is presented which shows that nepheline develops a preferred c-axis orientation in response to deformative stresses. It is believed that this is the first record of a stress-induced preferred orientation of nepheline.
On an Occurrence of Fayalite Quartz-Monzonite in the Basement Complex around Bauchi, Northern Nigeria
Authors: Oyawoye M. O.
Published: May 2009

An unusual fayalite-bearing quartz-monzonite occurs around Bauchi in Northern Nigeria and is distinguished from the high-level fayalite granites of the Newer Granites ring complexes by the presence of a linear structure conformable with those in the surrounding rocks, the gradational nature of its contacts, the extreme coarseness of its mineral constituents and the abundance of myrmekite. It is similar to them in its distinctive green colour and in the high FeO: Fe2O3 ratio. The rock is believed to be definitely older than the rocks of the ring-dyke complexes.
The Preparation of Thin Sections of Clays
Authors: Catt J. A. , Robinson P. C.
Published: May 2009

Methods of impregnating clays with the cement Lakeside 70C and two resins of the Araldite range are described and some details of the techniques of mounting and grinding specimens are included.
Stratigraphy of the Skiddaw Group between Buttermere and Mungrisdale, Cumberland
Authors: Jackson Dennis E.
Published: May 2009

The Skiddaw Group between Buttermere and Troutbeck is approximately 6,000 feet thick and can be subdivided into four formations which in ascending order are: Hope Beck Slates; Loweswater Flags; Mosser-Kirk Stile Slates; Latterbarrow Sandstone. The coarser elastics exhibit most of the characteristics of sediments deposited by turbidity currents. The source of these deposits is thought to lie to the south. The occurrence of contemporaneous vulcanism in the Loweswater Flags on Watch Hill has been confirmed. Tourmaline and andalusite are recorded for the first time from the metamorphic aureole east of Crummock Water.
Metamorphic Segregation Structures from Rosguill, Eire
Authors: Knill Diane C.
Published: May 2009

Rafts of semipelitic rock, included within a granitic body, contain segregations of microcline, biotite, cordierite and sillimanite. These structures appear to have resulted from a process of localized metasomatic rearrangement.
A Cambro-Ordovician Fauna from the Hecla Hoek Succession of Ny Friesland, Spitsbergen
Authors: Hallam A.
Published: May 2009

A short description is given of Cambrian and Ordovician fossils from near the top of the Hecla Hoek succession in Ny Friesland and the relations with other areas is briefly discussed.
Views on Spore Nomenclature
Authors: Potonié Robert
Published: May 2009

Spore nomenclature and palaeobotanical nomenclature follow exactly the same rules. In both there are difficulties which must be understood historically.
Contrasted Styles of Folding in the Rocks of Ord Ban Mid-Strathspey
Authors: Weiss L. E. , McIntyre Donald B. , Kürsten Martin
Published: May 2009

On Ord Ban, quartzite in superposed recumbent folds trending north–south is separated by a slide from mica-schist, granulite, and marble folded in monoclines trending east–west. The reasons for distinguishing between these two styles of folding are given, and the characters of the two styles are contrasted. A fold in quartzite and a fold in marble are described in detail, and kinematic interpretations are attempted. It is concluded that evidence of an early deformation involving mylonitization has been preserved in the quartzite, and that the latest tectonic event distinguishable was the production of the monoclines with attendant twinning of calcite and dolomite.
The Geology of North-East Jan Mayen
Authors: Nicholls G. D.
Published: May 2009

Field observations collected on a short expedition to Jan Mayen indicate that ankaramite was extruded at three different periods at the north-eastern end of the island, either as lava flows or pyroclastic deposits. Cycles of volcanic activity, in which the earlier lavas are ankaramite and the later ones trachybasaltic, have been recognized.
Stone Stripes in Breckland, Norfolk
Authors: Watt A. S.
Published: May 2009

The usefulness of plants in directing the attention of the archaeologist to likely sites of human occupation is well known. Their value to the geomorphologist is indicated in the following example, which puts on record the existence of stone stripes in Breckland.
Biotitite in the Basement Complex of Southern Nyasaland
Authors: Morel S. W.
Published: May 2009

Recent work in the Middle Shire Valley has revealed a swarm of biotitite bodies emplaced in gneisses and granulites of the Basement Complex. The rocks of the Basement Complex are described briefly and referred to the Amphibolite and Granulite Facies of regional rnetarnorphism. The field relations, distribution, and petrology of biotitite bodies show that they are a series of metamorphosed ultrabasic intrusions. An occurrence is described in which hydrothermal agencies have altered biotitite to vermiculite rock.
On the Supposed Transformation of Tillite to Granite at Mount Fitton, South Australia
Authors: Chinner G. A. , Sando M. , White A. J. R.
Published: May 2009

The transformation of tillite to granite and gneiss by granitization has recently been postulated for rocks of the Mount Fitton area of South Australia. After examining the relationships in the field we have concluded that another interpretation is possible; the granites could be regarded as an older basement upon the eroded surface of which the tillites have been laid. The zone of feldspar rich rocks between the two could represent a basal arkose resting directly on the old granitic surface.
The Stratigraphy and Folding of some Metamorphosed Moine Sediments around the Carn Chuinneag and Inchbae granitic gneisses
Authors: Harker R. I.
Published: May 2009

By studying the current bedding in the hornfelsed rocks surrounding the ortho-gneisses of the Carn Chuinneag and Inchbae masses it has been possible to obtain some indication of the stratigraphic order and the nature of the folding of this part of the Moine series.
A Note on the Field Relations of the Shiant Isles' Picrite
Authors: Drever H. I.
Published: May 2009

The picrite of the Garbh Eilean–Eilean an Tighe sill occurs at a number of points not previously recorded. Its junction with the overlying picrodolerite is not gradational and it does not maintain a uniform level in the sill.
The Olivines of the Garbh Eilean Sill, Shiant Isles
Authors: Johnston R.
Published: May 2009

Optical methods are employed in the re-determination of the composition of the olivines throughout the Garbh Eilean Sill. The olivines in the upper picrodolerite and the crinanite are zoned. The range of zoning and the iron content of the olivines increase progressively with height in the sill.
Magmatic and Amygdaloidal Plagioclases
Authors: Le Bas M. J.
Published: May 2009

Thermal metamorphism of zeolites in amygdales of basaltic rocks is shown to give glomero-porphyroblastic aggregates of plagioclase crystals. Plagioclase phenocrysts in basic rocks are shown to undergo but little change during similar degrees of metamorphism.
A Camptonitic Dyke Suite at Monar, Ross-shire and Inverness-shire
Authors: Ramsay John G.
Published: May 2009

A swarm of basaltic and camptonitic dykes in the Northern Highlands of Scotland has been studied. The dykes include monchiquite, olivine basalt, olivine dolerite, and camptonite, and a study of the relations of the various types in individual dykes suggests that the camptonites have arisen by the crystallization of late fractions from a magma of fairly normal dolerite type.
Miocene Beds of the East African Coast
Authors: Eames F. E. , Kent P. E.
Published: May 2009

New discoveries of marine Lower Miocene beds on the Tanganyika and Kenya coasts and on the adjacent larger islands are briefly described, and the palaeontological evidence establishing their age outlined. Previous palaeontological evidence has had to be reassessed, a considerable number of supposed Pliocene index fossils having been found to occur in the Lower Miocene. The “ Chlamys werthi Beds ” are shown to include strata of both Lower Miocene and Pliocene ages.
The Ben Lui Recumbent Syncline (S.W. Highlands)
Authors: Cummins W. A. , Shackleton R. M.
Published: May 2009

Structural evidence from the Ben Lui district supports Bailey's view that the hinge of a major recumbent fold can be demonstrated there. Way up evidence indicates that all the recumbent structures from the Ben Udlaidh fold upwards face towards the south-east and south-south-east. The Ben Udlaidh and Ben Lui folds are therefore synclines. The attitude and character of the folds suggest gravitational flow.
Phricodothyris in New South Wales
Authors: Campbell K. S. W.
Published: May 2009

The relations of the genera Torynifer Hall and Clarke, Phricodothyris George, and Kitakamithyris Minato are discussed, and the diagnosis of Phricodothyris emended. The phricodothyrid species of New South Wales all bear dental lamellae and a median septum in the pedicle valve. Four new species from three horizons within the Carboniferous are described.
A Note on the Mineralogy and Petrology of the Calciphyres near Nanjangud, Mysore, India
Authors: Subramaniam A. P.
Published: May 2009

The calciphyres and granulites near Nanjangud in Mysore were examined in detail in view of the reported occurrence in them of a remarkable assemblage of rare minerals of the Sanidinite fades. A brief field examination disclosed the absence of Gabbrolimestone contacts previously reported. The calciphyres and calc-granulites occur as layers, lenses and nodules in a group of amphibolites and hornblende granulites. Thin sections of these granulites display cataclastic textures indicative of shearing, and crushing. They are found to be composed of minerals characteristic of high grade marbles, and the absence in them of such minerals as larnite, merwinite and spurrite recorded previously, is consistent with the present field observations.
A Lingula-Bed in the Keuper of Nottinghamshire
Authors: Rose G. N. , Kent P. E.
Published: May 2009

Numerous specimens of Lingula tenuissima Bronn have been discovered in the Lower Keuper near Eakring, Notts. Earlier records of fossil bivalves in this formation are recalled and the implications of the present find discussed in relation to conditions of deposition of the Keuper.
Mugearites and Oligoclase-basalts
Authors: Wells A. Kingsley
Published: May 2009

A plea is made for the wider use of concise descriptive phrases instead of rock-names of the conventional type, which are usually uninformative. The writer's case is discussed in relation to the so-called “mugearites”.
The Clinopyroxenes of the Garbh Eilean Sill, Shiant Isles
Authors: Murray R. J.
Published: May 2009

Ten clinopyroxenes have been investigated chemically and optically. Eight of these were separated from the rocks of the Garbh Eilean sill and two from other rocks relevant to this inquiry into the trend during crystallization of pyroxenes in minor basic intrusions of mildly alkaline and undersaturated type.
A New Species of Carbonicola from near the Base of the Namurian in Ayrshire
Authors: Bennison G. M.
Published: May 2009

The marine Johnstone Shell Bed, an important index horizon in the Limestone Coal Group of the Carboniferous of Scotland, is succeeded in North Ayrshire by a bed containing Lingula squamiformis Phillips, and many small shells here referred to a new species of the genus Carbonicola. This Carbonicola community has been examined in detail, and graphical representation of the great variability has been employed.
Relations of Torridonian to Durness Limestone in the Broadford–Strollamus district of Skye
Authors: Bailey E. B.
Published: May 2009

Evidence strongly suggests that the Durness Limestone in Skye is a great thrust-slice between Torridonian above, at Broadford, and Torridonian below, at Strollamus and Scalpay.