bluuebunny/crossref_metadata_2025 huggingface dataset:
The controlling mechanism of Carboniferous cyclic sedimentation
Authors: BOTT MARTIN HAROLD PHILLIPS , JOHNSON GEORGE ANTHONY LOBJOIT
Published: October 2009

The Carboniferous cycles of sedimentation of Europe and North America are particularly well developed examples of a phenomenon which occurs throughout the geological column. The Carboniferous cycles are shown to be caused by sedimentation following an abrupt rise in sea level relative to the plane of deposition.

Changes in sea level relative to the plane of deposition may take place either from eustatic sea level changes or from vertical crustal movements of tectonic origin. Corresponding to these possibilities, two hypotheses have been proposed to explain the controlling mechanism of sedimentary cycles: (i)
the eustatic hypothesis
—cyclo-thems are formed in a subsiding region as a result of eustatic changes in sea level; (ii)
the tectonic hypothesis-
—in a subsiding region cyclo-thems are formed by subsidence of the crust taking place in rapid steps separated by longer periods of relative quiescence.

Examination of sedimentary cycles at the margins of Carboniferous basins shows that they do not conform to the pattern which would be expected if the sea-level changes were eustatic. This is because eustatic rise in sea level must equally affect the margins and central part of the area of deposition. Deposits of this type are rare in the geological column outside the Quaternary where eustatic lacustrine and sea level changes are known. They are unknown in the Carboniferous basins of deposition.

The tectonic hypothesis can be readily understood, however, in the setting of the mantle flow theory for the origin of sedimentary basins (
Bott 1964
). This theory links isostatic uplift of a denuding mountain range with contemporary sinking of adjoining basins and accounts for the presence of deep sedimentary basins filled with uniformly shallow water deposits. Modern ideas on the rheology of the crust and the upper mantle suggest that subsidence to form sedimentary basins may normally take place in sudden steps along fault lines. It is suggested that such repeated crustal subsidence provides an explanation of Carboniferous cyclic sedimentation.
Isotopic age-determinations of rocks and minerals from the British Isles, 1965
Authors: SABINE PETER AUBREY , WATSON JANET VIDA
Published: October 2009

This publication supplements that presented in the
Q. Jl geol. Soc. Lond.
vol. 121, part 4, pp. 477–533, 1965, relating to isotopic ages published in the decade 1955–64. During 1965 about seventeen papers were published containing some 250 new ages of British rocks and minerals. Abstracts of the new papers are now presented.

An attempt is made in each abstract to include locality, character and geological relationships of specimens investigated, method of dating, constants used, ages obtained and conclusions drawn.

A brief introduction and full indexes are provided (by P. A. Sabine & J. Watson) as in the previous publication.
The photogeological recognition of ancient orogenic belts in Africa
Authors: HEPWORTH JOHN VORD
Published: October 2009

Photogeological interpretation, assisted by some ground control, has been used to delineate areas of the crystalline basement in which structures formed during a particular tectonism are predominant. Such areas are referred to as 'tectonic domains'. They are recognized principally by distinctive tectonic style, by characteristic trend and axial direction, by metamorphic grade and by the sequence ot imposition of tectonisms. These criteria may be supported by geophysical data. It is unusual for all the criteria to be satisfied photogeologically, but with some ground information it is possible to draw maps which show the distribution of tectonic domains.

The tectonic domain map of Karamoja, north-east Uganda, shows four domains: an early granulite facies (charnockitic) east-striking domain (
A
); a second, north-striking, more widely developed amphibolite facies domain (
B
) in which
A
structures are reworked and partly obliterated; a
C
domain which cuts across the
A
and
B
domains in a series of straight, penetrative and partially cataclastic, north-west-trending structural belts which are parallel to the Aswa Zone of central Uganda; and the Karasuk domain of recumbent flaggy folds named after the Karasuk Group. Each domain is laterally bounded, replaced or 'overprinted' by another. These relationships are illuminated by those established elsewhere in northern Uganda, and the tectonic domain map is thought to depict the interplay in north-east Uganda of the Watian, Aruan and Ghuan tectonisms which may be orogenies, and to include the Mozambiquian front impinging upon older structures.

The value of the method of mapping tectonic domains lies in presenting, with a minimum of field-work, something approaching the normal tectonic map and so depicting the outlines of the ancient orogenic belts. Data such as age-determinations can be attached to the tectonic domain maps.
A tectonic study of part of the Philippine fault zone
Authors: RUTLAND RUPERT WILLIAM ROYE
Published: October 2009

The Philippine Fault Zone which trends
n
40°w is widely accepted as a major strike-slip fault comparable to the San Andreas fault. An area in south-eastern Luzon, commonly regarded as part of the main fault zone, has been studied in an effort to date the faulting and to establish its nature and extent.

Low-grade metamorphic rocks, of probable pre-Tertiary age, occur only on the north-east side of the Rift; their schistosity and bedding are folded on north-north-westerly axes. Marine early Tertiary formations follow unconformably on both sides of the Rift and locally are folded on east-north-easterly axes. Younger Tertiary terrestrial formations occur only on the south-west side of the Rift.

Two main episodes of faulting are recognized, one late Miocene on northerly faults, one Plio-Pleistocene on north-westerly faults. Both these episodes involve considerable dip-slip movements and the two principal Recent faults which have been recognized are also of dip-slip type. Geomorphological evidence shows that the whole area has been subjected to Recent episodic but areally uniform uplift.

Direct evidence of strike-slip movements is slight and the structural relations argue against major post-Miocene strike-slip movements. The possibility of earlier strike-slip cannot be excluded and the fault and fold systems show a good correlation with those predicted following the theory of Moody & Hill (1956). Possibly therefore the faults on which the main Miocene and later dip-slip movements occurred were initiated during earlier strike-slip episodes. A pre-Tertiary episode of left-lateral strike-slip in the Rift followed by a Miocene episode of right-lateral strike-slip on conjugate primary faults can be tentatively inferred. The direct evidence of faulting in the Rift, however, relates only to the Plio-Pleistocene activity of the morphogenic phase.
Radiometric time-scale for geomagnetic reversals
Authors: COX ALLAN , DOELL RICHARD R. , DALRYMPLE G. BRENT
Published: October 2009

A time-scale for polarity reversals of the geomagnetic field has been established for the last 4.1 m.y., using the potassium-argon method of dating rocks. The data for this time-scale consist of polarity- and age-determinations for about 240 rocks made by a number of workers; these are summarized in tabular form. At least 17 geomagnetic reversals occurred during the period covered, and intervals of constant polarity ranged in length from 700 000 years to about 50 000 years or possibly less. Two possible correlations of this time-scale with the Pliocene-Pleistocene boundary are discussed. In several parts of the world glacial deposits have been shown to be as old as 3 m.y., in some cases by application of the reversal time-scale either on land or in deep-sea sediment cores.
Volcanic and intrusive structures in the Kila-Warji ring-complex, northern Nigeria
Authors: TURNER DAVID CHARLES
Published: October 2009

The Kila-Warji massif is one of a large number of ring-complexes of Jurassic age which cut the basement rocks of northern Nigeria. It is the only large member of this Nigerian Younger Granite province in which rocks of intermediate composition are dominant over acidic rocks. Structurally the complex presents several features of interest. The southern part——Warji—is a cauldron subsidence structure of volcanic rocks invaded by partly concordant intrusions. In the north the Kila ring-complex consists of a cluster of almost superimposed intrusive ring-structures.

The complex lies in the extreme north of the Nigerian Younger Granite province (Fig. 1) and forms a group of low hills rising from an almost level plain developed on basement rocks. Farther north a few small complexes are exposed near the southern fringes of the Plio-Pleistocene sediments of the Chad basin, on the northern flanks of which Younger Granites reappear as large massifs in the Zinder-Gouré area of Niger (
Black 1963
) and at Matsena in Bornu Province (Turner, in press). The Kila-Warji complex, composed mainly of acid and intermediate volcanics, syenites and peralkaline granites, has closer affinities to these northern complexes than to the main part of the Nigerian province, where biotite-granites are the most abundant rock type.

Previous work on the area includes a preliminary survey by Raeburn (Falconer & Raeburn 1923) and an account of the petrography of some of the rocks by
Beer (1952)
. Field work for the present study was carried out from October 1965 to January 1966. This paper
The North Elgon Depression, eastern Uganda
Authors: CLARK LEWIS
Published: October 2009

The North Elgon Depression is a paravolcanic downwarp between the early Miocene volcanoes of Kadam and Elgon. The downwarp is filled with pyroclastic rocks from the two volcanoes. Recent percussion boreholes show lacustrine sediments at the base of the volcanic rocks.

The sub-volcanic surface is reconstructed in detail from borehole data and shows the early Miocene topography after modification by paravolcanic warping. The current drainage system is superimposed on that of the early Miocene.
The regional significance of the Caledonian structures of the Sandland Peninsula, West Finnmark, northern Norway
Authors: HOOPER PETER RALPH , GRONOW CLIVE WILLIAM
Published: October 2009

A detailed analysis of the mesoscopic structures of the Sandland peninsula is used as the key to the synthesis of the structural history of the Loppen district. Three fold episodes are recognized.
F
1 has folded the meta-sediments around the westerly-facing Haettekjeilen syncline, the steep, partly inverted easterly limb of which forms the Sandland peninsula and Silda, whilst the flat-lying westerly limb forms Loppa, the Andsnes peninsula, the Olderfjord meta-sediments and outcrops in the Kvaenangan Fjord. On Skjervøy, south of the Kvaenangan Fjord, the succession lies on the inverted limb of a westerly facing anticline, the axial trace of which must pass between Skjervøy and the Kvaenangan Gabbro.

These large westerly facing
F
1folds contrast with the large easterly facing
F
1 folds reported from Sørøy by Ramsay & Sturt (1963). Between the two areas a major
F
1anticlinal rise with a
n–s
trend is envisaged passing to the south of Sørøy and through the Loppen district where it follows the outcrop of the oldest meta-sediments exposed. These are intruded by a series of layered basic and ultrabasic bodies.

Three sets of
F
2 folds are described: major warps with vertical planes and a conjugate pair developed around easterly and westerly dipping axial planes. All have the same axial trend but develop on different parts of the
F
1fold system. The suggested maximum stress responsible was nearly horizontal in an
e–w
direction, very similar to that responsible for
F
1 and therefore unlikely to have modified greatly the regional orientation of the
F
1structures.

Later (
F
3) strain-slip cleavage and mild warps are associated with minor faults, shear zones and joints on near vertical planes with trends of 340°, 280° and 70°.
The origin of the Connemara migmatites of the Cashel district, Connemara, Ireland
Authors: LEAKE BERNARD ELGEY
Published: October 2009

After the Connemara schists, of Dalradian age, had been folded (
F
1) and metamorphosed to sillimanite grade, they were strongly hornfelsed by the intrusion of basic magma. From this magma crystallized peridotites, norites, pyroxenites and gabbros, all with An
80–87
plagioclase. Movements then caused the magma to break up these ultrabasic rocks and crystallization of basic rocks occurred. They are labradorite (An
55–65
)-hornblende-relic clinopyroxene rocks that grade into quartz-hornblende-labradorite (An
55
)-gneiss, quartz-hornblende-labradorite (An
55
)- and andesine (An
40
)-gneiss and quartz-andesine (An
40
)-hornblende-biotite-gneiss. These gneisses formed during strong
F
2 and
F
3 movements, and probably during amphibolite-facies metamorphism, and they broke up, injected, metasomatized and amphibolized the earlier basic and ultrabasic rocks, giving a heterogeneous migmatite that commonly contains two plagioclases, An
40
and An
55
. Quartzo-feldspath-ization of metasediment occurred, possibly up to a mile from the migmatites. This, and recrystallization, formed quartz-andesine (An
40
)-biotite-gneiss that merges into the magmatically crystallized gneisses as do gneisses formed by silicification of basic and ultrabasic rocks. Last to crystallize was K-feldspar gneiss, possibly formed by segregation of residual magma into one zone. This migmatite complex contains evidence of both magmatic and metamorphic crystallization of hornblende and the relative importance of each process remains to be determined. Tight
F
3folding formed the Cashel syncline, and a series of complementary folds. Later retrogressive metamorphism caused widespread chloritization, sericitization and saussuritization. Last of all was the intrusion of the Galway and Roundstone granites followed by their associated dykes. Twenty-four chemical analyses and nearly five hundred plagioclase determinations are utilized.
Statistical analysis of till fabric: methodology, local and regional variability (with particular reference to the north Yorkshire till cliffs)
Authors: ANDREWS JOHN THOMAS , SMITH DAVID INGLE
Published: October 2009

Problems connected with the sampling, interpretation and visual appraisal of till fabrics are discussed. Methods of statistical analysis are reviewed and a methodology for till fabrics presented. Fifty till fabrics from closely controlled sites allow a discussion of within- and between-site variability for this section of the Yorkshire coast. It is suggested that all the glacial deposits are of Newer Drift age. The till sequence can be divided into a basal shale-charged deposit and an upper dark red/brown till. Englacial or sub-glacial water-lain sands are also common and varved clays locally separate till sheets. Results indicate that till fabrics are characterized by low within-site precision, i.e. there is a considerable degree of orientation scatter, although dips are more compact. Between-site variability is moderate and is greater vertically within a deposit than laterally. Rotation of the data allows the typically bimodal distribution to be concentrated and analysed in the most efficient manner. A series of models are proposed for a rational description of fabric types and are linked to fabric genesis. Ice-flow, as revealed by the till fabrics, was north-south except in the vicinity of Robin Hood's Bay where an east–west component predominates. The reason for this difference is discussed. Distinct orientation and dip directions are more likely caused by flow within the till matrix rather than the ice/till contact.
Studies of sequence in sediments using a simple mathematical device
Authors: SELLEY RICHARD CURTIS
Published: October 2009

This paper introduces a simple method for objectively analysing the arrangement of beds in sequences of alternating rock types.

The number of times that different lithologies overlie one another in a section may be recorded in a table, termed the data array. The probability of one lithology overlying another in a section is a function of their frequency (i.e. the number of times that they occur), and the 'memory' of the depositional process. Since their frequency is known, from the data array, it is possible to calculate the number of times that different lithologies should be interbedded with one another if they were arranged at random. Comparison of these figures with the observed number of transitions (shown in the data array), picks out lithological transitions which occur more often than expected if they were randomly arranged. In such cases it can be said that one lithology has a good 'memory' for another. For example in the Coal Measures coal may have a good 'memory' for seat-earth.

The results of these studies are presented on facies relationship diagrams. These record the most probable upward and downward transition for each lithology in a section and can be used to detect the modal and composite sequences. After testing for memory a corrected facies relationship diagram may be constructed showing those transitions which occur more often than expected assuming a random model. It is these transitions which must be considered when postulating the sedimentary process which controlled the deposition of a rock sequence.

This method is applied to stratigraphical sections of the Paradox salt basin, U.S.A., Libyan Miocene shoreline deposits, fluviatile Torridonian (Pre-Cambrian) rocks of Scotland, and Yoredale (Lower Carboniferous) beds of northern England. All four cases show signs of memory in the vertical arrangement of their beds. The simplest examples show simple oscillatory motifs, both rhythmic (in the sense ABCABC) and cyclic (in the sense ABCBA). The more complex examples show arrangements due to up to three intertwined oscillations. The geological significance of these results is discussed.
Triassic rocks of the British Isles
Authors: KENT PERCY EDWARD
Published: October 2009

The proposal
for a symposium on the Triassic rocks of Britain sprang from two sources. The first was the inauguration by the Council of the Geological Society of a series of Committees to review the stratigraphical nomenclature and correlation of the Phanerozoic rock succession. It was apparent in the case of the Trias that existing published data provided an inadequate basis for such a review, and that it was desirable to organize up-to-date regional appraisals of modern information.

The second incentive was provided by the very vigorous discussion which followed the reading of Dr Audley-Charles' paper on the Stratigraphical Correlation of the Triassic rocks in Britain, a discussion which showed that much unpublished information in fact existed and that particularly critical aspects of the correlation could be investigated on the basis of existing data. In addition results of a study of the correlation of the German succession with the North Sea Trias and that of eastern England have now become available.

The major problem which has remained unsolved in British Triassic stratigraphy has been the establishment of reliable time planes, in a series which is essentially continental and lacking macrofossils, and in which classification has hitherto been entirely on a lithostratigraphical basis. New data of correlative value are now being supplied by palynological investigation, by evidence at some horizons from microplankton, by study of cyclothemic units and by electric, radioactive and mechanical logging of boreholes. The original basis of correlation is therefore being replaced by new lines of investigation many
The Triassic system in Britain and its stratigraphical nomenclature
Authors: AGER DEREK VICTOR
Published: October 2009

The present state of British Triassic studies and the origin of this symposium is briefly summarized. The inadequate nature of the present nomenclature is discussed. It is contended that the terms 'Bunter' and 'Keuper' should be abandoned and formation names in standard form given for all the rocks concerned. The value of lithostratigraphical correlation is emphasized and it is maintained that, in the case of the Trias, it is probably closer to a truly chronological correlation than is generally realized. This is especially true if one matches similar events in sedimentological successions rather than straight lithologies. The possible application of the standard Alpine stage names to the British Trias on this basis is suggested.
The stratigraphy of the so-called Keuper Sandstone Formation (Scythian–?Anisian) in the Permo–Triassic Cheshire Basin
Authors: THOMPSON DAVID BARNARD
Published: October 2009

The stratigraphy of the traditional Lower ‘Keuper’ Sandstone of Cheshire is reviewed. Two major lithofacies are defined: four Soft Sandstone sub-lithofacies are referred to fluvial, fluvial-lacustrine and aeolian origins; the seven Red Pebbly Sandstone sub-lithofacies to varying fluvial environments (channel-lag or race, migrating channel bars and megaripples, swales and flood-basins of both low and moderate-sinuosity streams), and possible intertidal lagoonal environments. Principles of stratigraphical classification are discussed, and the onset of Waterstones conditions and a widespread dune field taken as the datum below which lithostratigraphical correlation is attempted. Definition of the ‘Keuper’ Sandstone Formation and its constituent units, the Frodsham, Delamere, Alderley, Nether Alderley and Thurstaston Members, is made. The correlation suggests that following the mainly aeolian episode of the Bunter Upper Mottled Sandstone, low-sinuosity flood-waters of the ‘Keuper’ Sandstone entered the basin intermittently along certain directions, notably those of the Eastern (Midland–Congleton–Macclesfield and Alderley–Styal) and Central (Marston–Stockton) Rivers. Elsewhere aeolian activity continued, the rivers often drying out and being overwhelmed by blown sand. This was followed by the main fluvial period of the Delamere Member during which streams of moderate sinuosity were developed everywhere but in the south. The succeeding Frodsham Member represents a major aeolian episode which is terminated by low-energy aqueous sedimentation of the Waterstones. These correlations are partiularly open to testing by palaeomagnetic investigation and by spores.
Stratigraphy in mountain belts
Authors: TRÜMPY RUDOLF
Published: October 2009

The importance of stratigraphical research for the understanding of the structure and genesis of complex mountain chains was stressed and some of its special problems were discussed.

The main part of the lecture dealt with the sedimentary history of the Alps, from Upper Carboniferous to Lower Cretaceous time, and with its implications for the crustal development in the geosyncline. Continental Upper Paleozoic and uniformly shallow-water Triassic formations point to the existence of a normal continental crust before the onset of subsidence. Deeper basins, probably bordered by normal faults, developed gradually during the Jurassic, and in late Jurassic and early Cretaceous time the geosyncline may have been comparable to some of the present smaller ocean basins. This implies thinning of the original continental crust; nevertheless, large remnants of granitic basement are present even beneath eugeosynclinal sediments and ophiolitic volcanics. In the Alps, the stratigraphical sequence is better compatible with the hypothesis of oceanization (replacement of the lower part of the crust by denser matter) than with the mechanism of ocean-floor spreading according to the Atlantic model.
The Foyers granitic complex, Inverness-shire, Scotland
Authors: MARSTON RODNEY JOHN
Published: October 2009

The Foyers 'Newer Granite' is a composite pluton consisting of tonalite, granodiorite and adamellite emplaced in that order. The complex evolved by crystal-differentiation from a series of cooling magmas which were additionally modified by contamination with appinite, microdiorite and semi-pelite. A distensive foliation was progressively imparted to the units of the complex as they solidified, followed by post-magmatic alkali autometasomatism which extended into the envelope.

Parts of the roofing envelope remain and the outer, largely tonalitic mantle to the inclined funnel-shaped intrusion conforms structurally with the envelope. After some uplift the adamellite was emplaced under brittle conditions, but was also subjected to some distension. Intense movements along
ne–sw
faults before and after the deposition of the local Old Red Sandstone complicate relations on the north-western margin of the complex, which is truncated by the Great Glen fault. The respectively high and low structural levels of exposure of the Foyers and Strontian intrusions complicate comparison, but there are sufficient chemical and structural similarities to confirm their former unity before being displaced laterally and vertically by the Great Glen fault.
The Sgurr Beag Slide–a major tectonic break within the Moinian of the Western Highlands of Scotland
Authors: TANNER PETER WILLIAM GEOFFREY
Published: October 2009

Detailed mapping of an area at the head of Loch Hourn, Inverness-shire, has shown that major facies changes occur within the Glenelg–Knoydart succession (Ramsay & Spring 1962) as it is traced north-eastwards from the type area. A slide, here recognized as a tectonic break of major importance within the Moine Nappe, separates members of this succession at Kinloch Hourn from rocks of a different stratigraphical sequence farther east.

Lewisian-type rocks rest upon the slide plane and together with an overlying sequence of Moinian rocks have been slid against upper members of the Glenelg–Knoydart succession.

It is suggested that the Scardroy Lewisian, which forms a sheet-like body in central Ross-shire, has been brought to its present position by this slide movement and not thrust wedge-like into an unbroken Moinian succession as suggested by Sutton & Watson (1962).

Three phases of folding are recognized and the geometry of the major folds and their structural relationship to the slide plane is described in detail. Slide movement occurred during the second folding and before the peak of the regional metamorphism.
On a Fossil Forest in the Parkfield Colliery near Wolverhampton
Authors: Beckett Henry
Published: October 2009

The fossils alluded to in the following notice, occur in an open work, that is, the superincumbent strata have been pared off, and we find the coal (which belongs to what is called the “bottom coal,”) well exposed to view. The bed has been bared for upwards of two years, but the fossils do not appear to have attracted attention, till Mr. William Sparrow and myself, whilst tracing the great faults of the South Staffordshire coal-field, accidentally stumbled upon them, and were struck with their number and their evident resemblance to trunks of trees.

Since that time, by the kind permission of the Parkfield Company, and with the assistance of Professor Orlebar, of the Royal Bengal College in Bombay, I have carefully removed the coal attached to the roots of one of the trees.

We found the stump to be perfectly bituminized, but broken off about two inches above the level of the coal measure, the inner part being somewhat hollowed to about the level of the coal itself: the surface and edges of the broken part were smoothed or probably water-worn. The tree bared was not flattened, but preserved precisely the same appearance which I have noticed with peat timber in Ireland, and was 4 feet in circumference. The principal root extended southwards 22 inches, terminating abruptly.
Report on the Lower Green sand Fossils in the Possession of the Geological Society
Authors: Forbes Edward
Published: October 2009

The collection of Lower Green Sand fossils at present in the cabinets of the Society contains 131 species of Mollusca. Of these 82 are Lamellibranchiate Bivalves, 12 Brachiopoda, 23 Gasteropoda, and 14 Cephalopoda. Besides these, all well-marked species, there are a number of casts and fragments of species as yet undetermined.

Of the 131 Mollusca, 60 are additions to the list of Lower Green sand Fossils, published by Dr. Fitton in the “Geological Transactions.” Of these 60 additional species, between 30 and 40 are undescribed forms. The remainder are species described in the memoirs of Leymerie, D'Orbigny, Roemer, and other continental authors, but which have been hitherto unrecorded as British, with the exception of a few included in Mr. Morris's catalogue.

All the species have been critically examined, and characters drawn up of such as are new.

The collection can by no means be regarded as complete, numerous additions, including several very beautiful species, having been very lately presented to the Society; and these there has not as yet been time to examine and place in the cabinets.

Of the lower green sand Mollusca in the collection, 35 agree with Neocomien species recorded by M. Leymerie, and about 30 with species from the Hillsthon and Hillsconglomerat of M. Von Roemer. Many species, which had received new names from those geologists, have proved, on examination, to be well-known British species, figured in the Mineral Conchology or elsewhere.
Report on the Collection of Fossils from Southern India, presented by C. J. Kaye, Esq., F.G.S., and the Rev. W. H. Egerton, F.G.S.
Authors: Forbes Edward
Published: October 2009

In the descriptive catalogue accompanying this report, and referring to the remains of invertebrate animals in the valuable collection of fossils from the South of India, presented to the Society by Mr. Kaye, and increased by an extensive series of specimens collected in the same localities by Mr. Egerton, 168 species of Mollusca are enumerated, 156 of which, as far as can be ascertained, are undescribed forms. There are also a number of species of Radiata.
Some Remarks on the White Limestone of Corfu and Vido
Authors: Portlock
Published: October 2009

As I have reason to expect that I shall hereafter be able to prepare a detailed account of the Geology of the Ionian Islands, and have at present but few data for a description of even the limited portion of the country as yet examined, I now only offer a few remarks on that portion of the white limestone which is adjacent to the city of Corfu, and occupies the whole of the Island of Vido, and on the more recent strata connected with it.

On approaching Corfu the physical aspect of the country is very striking. Monte Decca on the south, and San Salvador on the north, the former with its sharp, broken, rugged outline, the latter with its conical peak rising from a long ridge, and both exhibiting steep faces marked by numerous deep furrows, by no means recal the ordinary forms of limestones in our more northern countries; but the type they present will, I think, be found to have a considerable geological range.

In the Venetian harbour of Govino a singular variety of this limestone may be seen, and is thence traceable in rough knolls running in a westerly direction to the north of the village of Potamo. Its dark, rugged and often ochreous aspect, its sonorous fracture, and its impurities, are strong features of distinction between it, and the ordinary white limestone.
Account of the Strata observed in the Excavation of the Bletchingley Tunnel
Authors: Simms Frederick Walter
Published: October 2009

A few months ago I had the pleasure of presenting to the Geological Society some fossils collected by me in the course of the construction of the Bletchingley Tunnel, upon the line of the South Eastern Railway. These fossils consisted of bones of the Iguanodon,
Lepidotus Mantelli
, and five specimens of the plant
Clathraria Lyellii
. I now request the Society's acceptance of a fine specimen of the
Lepidotus Mantelli
, which was found in the excavation about two hundred yards from the western extremity of the tunnel.

The range of hills formed by the escarpment of the lower green sand extends between Red Hill and Tilburstow Hill, and its direction is nearly from west to east. Between Bletchingley and Tilburstow Hill, this range sends off a spur in a southerly direction. It was through this spur, in a line nearly parallel to the sand range, and about a mile to the south of it, that the railway tunnel, and the excavation at each end, were carried. The spur, in the line of the cuttings, consisted chiefly of Weald clay.

It was proved by the railway cuttings that this spur formed part of an anticlinal axis, which, as far as I can judge, extends across the Weald from the chalk of the North Downs in Surrey, between Merstham and Grodstone, to the chalk of the South Downs in Sussex, near Ditchling.
On the
Thalassina Emerii
, a fossil Crustacean, forwarded by Mr. W. S. Macleay, from New Holland
Authors: Bell T.
Published: October 2009

This fossil, forwarded from Mr. Macleay and brought by Lieutenant Emery from Australia, belongs to the typical genus of a very remarkable family of decapod Crustacea, the
Thalassinidæ
(
Thalassiniens
of Milne Edwards), as Mr. W. S. Macleay has surmised. Of the genus in question,
Thalassina
, but a single recent species is known, and little has been ascertained respecting its habits. There is, however, reason to believe, that in this respect it agrees with the species most nearly allied to it in structure, several of which being found on our own coasts have afforded opportunities for more accurate observation. These, as far as their habits have hitherto been traced, are all of them burrowers, making their way to a considerable depth in the sand at various distances from the shore. The species of the genus
Gebia
, which is very nearly allied to the present, are all to be obtained by digging in the mud or sand at low tide; and the
Gebia stellata
, as stated by Dr. Leach, form subterranean, horizontal, and winding passages, “often of a hundred feet or more in length.” The same habit is also known to belong to Callianassa, another nearly allied genus.

The recent species of the genus to which the fossil belongs,
Thalassina scorpioides
, is stated by Leach, Desmarest, and others, to be a native of the Indian seas. Milne Edwards on the other hand gives the coast of Chili as its habitat.
On Fractured Boulders found at Auchmithie near Arbroath
Authors: Trevelyan W. C.
Published: October 2009

In a visit paid to the coast of Forfarshire in the summer of 1840, I observed, for the first time, at Auchmithie, near Arbroath, at the foot of a cliff consisting of old red conglomerate, some pebbles and boulders which had fallen from the rock above, and which, from their remarkable fractures and contortions, attracted my attention, and being in the same neighbourhood in the autumn of 1843, I found in the same spot many more specimens of the pebbles, some lying at the foot of the cliff and others remaining in their matrix.

Subsequently, in the picturesque conglomerate rocks at Dunottar Castle, near Stonehaven, I discovered similar appearances; but, in this instance, the pebbles were much larger, and the fractured ones even more abundant than in Forfarshire.

At Auchmithie, the pebbles which predominate in the conglomerate consist of granite, porphyry, gneiss, jasper, and reddish quartz—those of the quartz being chiefly abundant. Of most of these different kinds of pebbles, fractured specimens may be found.
On the Traces of the Action of Glaciers at Porth-Treiddyn, in Carnarvonshire
Authors: Byres Robert W.
Published: October 2009

The following notice, bearing date the 16th of October, 1841, appeared in the Visitors' book at the Goat-Hotel, Beddgellert:— “Notice to Geologists.—At Pont-aber-glas-llyn, 100 yards below the bridge, on the right bank of the river, and 20 feet above the road, see a good example of the furrows, flutings, and striæ on rounded and polished surfaces of the rock, which Agassiz refers to the action of glaciers. See many similar effects on the left, or south-west, side of the pass of Llanberris. WILLIAM BUCKLAND.”

This notice led me to search for the same effects in other places in the same neighbourhood, and I found similar traces on many of the rocks between Aber-glas-llyn bridge and Tremadoc. In February last curiosity led me into the Flag-quarry, which lies about 300 yards from the mail-coach road, at Porth-Treiddyn; and for the purpose of examining the joints and split of the rock, I ascended from the quarry to the top, where a space of ground had been cleared of the soil and detritus, preparatory to further quarrying. Here I was much struck by the polish and undulations of the surface of the rock; and a detail of my examination of these phenomena will leave no doubt, I think, that they are attributable to the action of glaciers.

The slope of the mountain at Porth-Treiddyn is to the north and north-east; and the dip of the rocks is in the same direction, at an inclination of from 17° to 22°, but the angle increases as you ascend
On the Existence of Flouric Acid in recent Bones
Authors: Owen Rees G.
Published: October 2009

The author in this communication wished to direct the attention of geologists to the experiments connected with the presence of fluoric acid in bones that have undergone no change consequent upon fossilisation. He states that in the experiments he made, the bones were tested both before and after calcination, but that there was nowhere the slightest indication of fluoric acid in recent human bones, although immediate evidence of its presence was obtained when fossil ivory was submitted to examination.
Comparative Remarks on the Sections below the Chalk on the Coast near Hythe, in Kent, and Atherfield, in the Isle of Wight
Authors: Fitton W. H.
Published: October 2009

My objects in this paper are to illustrate, 1st, two Sectional elevations, showing the proportional thickness of the principal divisions of the strata at Hythe and Atherfield ; 2dly, an approximate sketch of the cliffs from Atherfield to the East of Blackgang-Chine; and 3dly, a corresponding sketch of the section from the chalk hills above Folkstone, to the level of the sea at Hythe.
On the Section between Black-Gang-Chine and Atherfield Point
Authors: Ibbetson L. L. B. , Forbes Edw.
Published: October 2009

The accompanying Table exhibits the succession of strata presented in ascending order from the Wealden to the top of the Upper Green Sand in the Isle of Wight between Atherfield Point and St. Catherine's Down. The measurements of the upper portion were ascertained by trigonometrical survey, by Capt. Ibbetson, during the years 1833–38, those of the lower portion during the winter of 1842–3.

The following observations refer to that portion of the section which includes the Lower Green Sand strata, visited by Capt. Ibbetson and Prof. Forbes in March, 1844.

Between the Gault, as seen near Black-Gang-Chine, and the. Wealden at Atherfield Point, there are sixty-three distinct strata, the total thickness of which is 843 feet.
On some Crustaceous Remains in Carboniferous Rocks
Authors: Ick W.
Published: October 2009

This communication accompanied two electrotype casts of the specimens alluded to. The one was found in the white ironstone measures at Ridgeacre Colliery, and the author states,—“I at first thought it might be the head and carapace of a new species of
Eryon
except that the known species from the Solenhofen slate are much more deeply notched on the edges of the carapace, and the apparently spinous prolongation of the head and some other details do not agree. The white ironstone in which it was found is a bed in the lower part of the field below what is called the New Mine coal. It is the bed in which the finest remains of Megalichthys have been found.”

“The other fossil is in an ironstone nodule. The form is not so well defined as in the first, and I dare not venture to guess to what it may be referred.”
On the probable Age and Origin of a Bed of Plumbago and Anthracite occurring in mica-schist near Worcester, Massachussetts
Authors: Lyell Charles
Published: October 2009

A bed of plumbago and impure anthracite described by Professor Hitchcock in his “Geology of Massachussetts” is found interstratified with mica-schist near Worcester, forty-five miles due west of Boston. It is about two feet in thickness, and has been made use of both as fuel and in the manufacture of lead-pencils. It is much mixed up with the associated rock, has the touch and somewhat of the lustre of plumbago, and gives a streak on paper. It is occasionally iridescent like coal, contains pyrites, which is also found in the associated clay slate and garnetiferous mica-schist, both of which are impregnated with carbonaceous matter. This- plumbaginous rock presents numerous polished surfaces or slickensides, on some of which are delicate parallel striæ, which reminded me so strongly of the finely striated leaves common in coal, that I had first supposed them to be of the same nature; and was thus induced to search very diligently, but in vain, for vegetable impressions.
On the Geology of Cape Breton
Authors: Brown Richard , Lyell Charles
Published: October 2009

I Propose, in the following pages, to give a slight general sketch of the geology of Cape Breton, from notes made at various times, some so far as 15 years back, and collected more with a view to professional pursuits, than for the purposes of geological research.

The island of Cape Breton is separated from Nova Scotia by the Gut of Canso, and is about 120 miles in length from north to south, and 90 miles wide from Scatari on the Atlantic shore to Port Hood on the Gulf of St. Lawrence. A range of highlands, commencing at Cape North, continues to St. Ann's on the east shore, and to Margarie on the west shore, both distant from Cape North about 60 miles, and presents, with few interruptions, bold and precipitate cliffs to the ocean. These highlands attain their greatest elevation near the shore, constituting a table-land from 15 to 20 miles in breadth, and 600 to 1000 feet in height, in most places incapable of cultivation. Part of this table-land is covered with a stunted growth of spruce and fir trees, and the remainder is principally rocky and barren moorland, which affords a scanty supply of moss for a few herds of wild deer.

From Margarie to Port Hood the country is elevated, but undulating, being intersected by several small rivers running through valleys of great fertility.
On the Stonesfield Slate of the Cotteswold Hills
Authors: Brodie P. B. , Buckman James
Published: October 2009

The district alluded to in this memoir is situated to the east of Cheltenham, and includes the Cotteswold Hills, which divide the county of Gloucester from parts of the neighbouring counties of Oxford, Worcester, and Warwick.
On certain Calcareo-corneous Bodies found in the outer chambers of Ammonites
Authors: Strickland H. E.
Published: October 2009

In 1841, Miss Anning, of Lyme Regis, drew my attention to some black-coloured substances which she had occasionally met with in the interior of the
Ammonites Bucklandi
, and which she considered to indicate the presence of an ink-bag in the animal of the
Ammonite
, corresponding to that of the Sepiidæ. From these and other specimens, it appeared to me evident that these substances had constituted, not an ink bag, but a laminar appendage to the animal, adapted to discharge some unascertained function. The specimens presented the appearance of a very thin concave shell, glossy on its outer surface, with irregular concentric undulations, crossed by longitudinal striæ and fine irregular oblique wrinkles. In the middle of the external margin is a large undulation or sinus. The inner surface, as exhibited by its cast, is of a dull black, the outer surface of the shell being of the colour of horn. Miss Anning informed me that these bodies generally occur about the middle of the outer chamber of the ammonite, whence they are obtained by breaking the fossil; but as this process more frequently destroyed than exposed the object of search, I was unable, during my stay at Lyme Regis, to procure any tolerably perfect specimens, or to arrive at any satisfactory conclusion as to their nature.
Notice concerning the Tertiary Deposits in the south of Spain
Authors: Smith James
Published: October 2009

In the bay of Gibraltar, immediately to the north of the plain which separates the fortress from the Spanish territory, we meet with a series of low swelling hills of yellow rubbly sandstone, the beds dipping to the S.W. at an angle of 12°, and abounding in marine tertiary fossils. Of these fossils, there is only a small variety, and of many of the species I could only find casts; but these were sufficient to furnish an important link, connecting distant deposits; for upon comparing them with the specimens in the Society's Museum, illustrative of Col. Silvertop's account of the tertiary formation of Murcia and Grenada, and Lieut. Spratt's paper on the Geology of Malta, I find that the three deposits are identical.

I have also observed tertiary beds at Cadiz, and between Xeres and Seville, which, I am satisfied, belong to the same deposit; and Mr. Sharpe, in his paper on the Geology of Lisbon, has assigned reasons, with which I entirely agree, for considering that the tertiary beds of the Tagus coincide with those of the south of Spain.
On the Geology of Gibraltar
Authors: Smith James
Published: October 2009

In the absence of the author of this paper from England it has been considered advisable not to publish more at present than a mere announcement of the nature of the conclusions arrived at. After stating briefly the appearance and character of the fundamental rock at Gibraltar (which is of the oolitic period), the author mentions indications of recent marine action, extending up to the very summit of the mountain, and proceeds to describe his reason for concluding that great and repeated elevations have taken place in the district in comparatively modern periods, three being more especially remarkable, since each one of these has elevated the strata through an angle of about 20°. Several interesting phænomena of the tertiary period are alluded to as affording evidence in favour of this view. The author concludes by directing attention to some superficial deposits of sand, covering the flanks of the mountain, and to the bone breccia, some parts of which he considers to be of great age.
On the Discovery of the Fossil Remains of Bidental and other Reptiles in South Africa
Authors: Bain Andrew Geddes
Published: October 2009

The district in which these fossils were found is on the eastern frontier of the Cape Colony in South Africa, about 500 miles east of Cape Town. No granite has been observed here, and the lowest rocks are stratified, and in consequence of the dip, though variable, tending on the whole towards the interior of the country, the lower members of them are those nearest the coast.

A red quartzose crystalline sandstone is described by the author as the fundamental rock, and as alternating with a talcose slate. This sandstone is assumed to be of the carboniferous period, vegetable impressions, apparently of a Lepidodendron, having been found in it, and it is traced by the author towards the west, parallel to the coast to within 50 miles of the Cape.

Over this there occurs a rock, called by the author a claystone porphyry, containing fragments of the sandstone; next an argillaceous slate, alternating with sandstone and containing thin laminæ of limestone, and at a little distance is a stratum full of vegetable remains.

Further to the north is a ferruginous sandstone with argillocalcareous nodules, in which nodules were found the, remains of reptiles characterised by the author as
Bidental
, and described by Professor Owen in the subsequent memoir.