bluuebunny/crossref_metadata_2025 huggingface dataset:
Note on the Occurrence of Blastoids with Brachioles at Hook Head, Co. Wexford, Ireland
Authors: Wright James
Published: May 2009

Among interesting finds at Hook Head are several specimens of a species of Blastoid with the brachioles in position. A few also have part of the column attached. The species has not yet been worked out, but it probably belongs to the genus Orophocrinus. The calices are mostly crushed and for that reason may be difficult to identify, but so far as a somewhat cursory examination has shown they belong to a species similar to O. pentangularis Miller. Blastoids in this condition do not seem to have been recorded from European rocks before. In the Catalogue of the Blastoidea in the Geological Department of the British Museum, published in 1886, Etheridge and Carpenter state on p. 63 that no traces of brachioles have been discovered in any European Blastoid. I do not know of any record since. They are rarely found in this state of preservation even in America, so it seems worth while placing the specimens on record now. Dr. L. B. Smyth records Orophocrinus pentangularis Miller from the Upper Michelinia antiqua Beds at Hook Head, also a Blastoid from the Upper Michelinia favosa Beds, but he informs me he has never seen any of these organisms in the above state of preservation before. Our specimens occurred on a thin shaly layer on top of a limestone in the Supra-dolomite Beds at Doornoge Bay. Like ours, the specimens recorded by Dr. Smyth also have calices which are mainly flattened, so I was interested to find in the Austin Collection in the Liverpool Museum several specimens which are fairly round and solid. Over thirty specimens are labelled from Hook Head. This corresponds with the names in the MS. catalogue which are given as Pentremites pentangularis, P. acutus, P. oblongus, and P. enniskilleni. The last named is also given in the catalogue from Co. Fermanagh.
Some Vertebrate Fossils from Ceylon
Authors: Deraniyagala P. E. P.
Published: May 2009

Although fossil plants of Jurassic age are known from an area of about a square mile at Tabbova and Miocene marine invertebrates have been recorded from several coastal localities, there is no authentic record of vertebrate fossils from Ceylon. It had hitherto been suspected that local conditions were not conducive to the preservation of bones, but it now transpires that there are such fossils which are as interesting as those of India or Burma.
Petrographic Nomenclature
Authors: Wells A. K.
Published: May 2009

In February, 1932, the British Association Committee appointed to examine and report upon petrographic classification and nomenclature issued a questionnaire in the GEOLOGICAL MAGAZINE and in Science, in order to ascertain what measure of agreement, if any, exists among petrologists as to the principles upon which a rational system might be established.
The Two Monzonitic Series of the Newry Complex
Authors: Reynolds Doris L.
Published: May 2009

In a study of the rocks of the eastern end of the Newry Complex, the writer distinguished two contrasted groups of hybrid rocks— (i) the Slievegarron type, and (ii) the Seeconnell type—both of which are intimately associated with biotite-pyroxenite and biotite-peridotite. The Slievegarron hybrids comprise an augite-biotite-diorite series. The typical augite-biotite-diorite (1934, p. 611) is a highly undersaturated rock heteromorphous with certain varieties of orthoclase-basalt and leucite-basanite; it might equally well be described as biotite-essexite-gabbro. No further discussion of these rocks will be undertaken in this paper, but it seems desirable to point out that they should not be confused—as unfortunately they have been—with gabbro-diorite.
Levels in the Raised Beach, Black Rock, Brighton
Authors: Smith Bernard
Published: May 2009

In 1932 during the early stages of the construction of the undercliff sea wall between Brighton and Rottingdean, whereby the foot of the cliff has now been protected from marine erosion and its top from undue recession in future, opportunity was taken to examine the sections of Coombe Rock and Raised Beach exposed at Black Rock. The face of the cliff has been trimmed and sloped back here and there in the interests of promenaders beneath and, what with this and a certain amount of walling-up, the sections are now less clear and extensive than they were in the first stage of the work. At several points, however, the Raised Beach overlain by the Coombe Rock (“Elephant Bed”) is (April, 1936) well exposed, and its top and/or bottom may still be examined.
The Arrochar Intrusive Complex
Authors: Anderson J. G. C.
Published: May 2009

The present paper deals with a number of intrusions lying within a north-easterly oriented belt of country, 4 miles wide and 12 miles long, running from a point 1½ miles west-south-west of the Brack, through the Arrochar mountains and across the head of Loch Lomond, to the upper reaches of Glen Gyle, 3 miles east of Ardlui (Text-fig. 1). Only one of these attains any considerable size. It lies north-west of the head of Loch Long and may be called the main Arrochar intrusion.
A Description of Eospirifer radiatus (J. de C. Sowerby)
Authors: Joseph J. K. S. St.
Published: May 2009

In 1825 J. de C. Sowerby described and figured as Spirifer lineatus a brachiopod from the “ Wenlock Limestone ” of Dudley, choosing three syntypes; later he changed the specific name to radiatus. Of subsequent descriptions those of Hall (1852), Davidson (1866), Beecher and Clarke (1889), and Hall and Clarke (1894) are the most important. The present study is based on topotype material, while additional specimens for comparison have been collected by the writer from the Wenlock Shale of Malvern (Colwall Tunnel Tip Heap), from the Woolhope Limestone of Suckley, from the Wenlock Limestone of May Hill, and from the Tickwood beds and Wenlock Limestone on Wenlock Edge (railway cuttings near Presthope and Lilleshall Quarry). These, together with specimens from the Sedgwick Museum Collection, from the Birmingham University Collection, and from the British Museum (Natural History), have provided material adequately representative of variations in shape and size. Study has been made of external features, but more particularly of internal characters. The method of investigating the internal structures consists in grinding down the specimen either from the umbones, or from the lateral margin, and taking serial cellulose transfers at regular intervals, from which enlarged scale models may be constructed. Five specimens have been so treated, and as well as the construction of models, use has been made of perspective scale drawings to show the variations in internal structure. Growth lines are preserved on the transfers, but have in addition been examined in thin sections; specimens from Haverfordwest and Rubery preserved as casts have served to throw light on the muscle system, while finally the ventral valves of specimens preserved in shale, have been prepared to show the variations in internal structure.
The Chalk Rock Fauna in East Yorkshire
Authors: Wright C. W.
Published: May 2009

Recently there was discovered in a quarry at Kiplingcotes Station, East Yorkshire, an iron-stained and sometimes nodular chalk, which appears to be a lenticular patch, varying from 0 to 18 inches in thickness. It is situated in a spur between two lime kilns and contains an abundant fauna. The rock bears more resemblance to some of the bands of iron-stained nodules that form the Chalk Rock of Surrey than to the characteristic hard limestone. The quarry is apparently fairly near the top of the Holaster planus zone and has, for a long time, been known to be very fossiliferous.
A Simple Method of taking Serial Sections
Authors: Caldwell F. E. S.
Published: May 2009

The two chief difficulties in taking serial sections are to ensure that the successive sections are all parallel to each other and to obtain reliable drawings of them.
Some Early Mesozoic Plants from the Tanganyika Territory
Authors: Seward A. C.
Published: May 2009

The specimens described in the following pages were submitted to me for examination by Mr. F. R. Parrington, who obtained them “from the hard fine-grained flags in the bed of the Msimbasi River between the junction of a tributary called the Katkindu and the site where reptile remains (? Tangasaurus menneli) were collected about half a mile above the junction, approximately 4° 55′ S. lat.; 38° 57′ long.” (Sketch-map, I.) Though the material is for the most part fragmentary, it is a welcome addition to the palaeobotanical records from tropical Africa. The plants are from the region where Dr. E. O. Teale made a collection, which was described twelve years ago. Specimens from the same district and from beds of the same geological age had previously been described by Potonie. Teale assigned the plant-beds to the middle division of the Tanga series of the Karroo system and Potonié regarded the beds at his “Fundort V”, which corresponds to Mr. Parrington’s locality (sketch-map, I) as Rhaetic-Jura (?). My conclusion was that the plants indicated a Triassic or Rhaetic age. The additional fossils which Mr. Parrington kindly handed to me, though they cannot be said definitely to settle the age of the beds, indicate an Upper Triassic horizon.
The Quaternary Changes of Ocean Level: Cause and Consequences
Authors: Johns Cosmo
Published: May 2009

In a preliminary article (1) dealing with the British Quaternary strand-line oscillations it was shown that unexpected correlations had emerged as a result of the methods employed. Of the possible assumptions the only one to prove workable was that there had been, during Quaternary time, a temporary lowering of ocean level of 1,000 metres or more. The graphs left no reasonable doubt that if the ocean level had moved in the way assumed the Mindel-Kiss interval of Penck's Alpine sequence must be equated with the major glaciation of North-West Europe and the British Isles. In order to test this, the only assumption made, it was applied to the coral reef problem (2) and there it was successful in offering what should be an acceptable solution. It was surprising to find that Darwin had actually used an apparent rise of ocean level, of the same order of magnitude, to illustrate his own theory of subsiding islands. The success of the postulate when faced with the coral reef problem was held to have invested it with a high degree of probability. It was pointed out, however, that changes in ocean level of that magnitude could best be explained by the sinking of the ocean floor, and the North Pacific Ocean was indicated as the probable position. The cause of the changes of ocean level will now be investigated and then its consequences discussed in the light of ascertained facts.
Differentiation in Basalt Lava, Island Magee, Co. Antrim
Authors: Tomkeieff S. I.
Published: May 2009

THE plateau-lavas of Antrim cover an area of approximately 1,550 square miles—the largest area of Tertiary lavas in the British Isles. Although from the earliest daysof geological science these lavas have attracted many observers, very little has been done in the way of petrological study and, curiously enough, the dominant olivine-basalt lava has never been analysed.
Note on the Flora of the Highest “Coal Measures” of Warwickshire
Authors: Dix Emily
Published: May 2009

Recently the author has been investigating the sequence of floras and faunas in the Warwickshire Coalfield. In the course of this work particular attention has been given to the flora of the barren Upper Coal Measures, which, according to Eastwood (1923, p. 42), includes the Keele Series and at least 1,700 feet of the Corley or Enville Series. Vernon, on the other hand, placed the latter in the Permian (1912, pp. 590, 603), and he noted that the Corley Series rests unconformably on the underlying Upper Carboniferous strata. Shotton, however, stated (1929, p. 169) that in this area he could see “no evidence for any Permian System (in the sense of System being separated from the Carboniferous by an unreprented time-interval)”.
On the Structure and Affinities of the Carboniferous CochliodontHelodus simplex
Authors: Moy-Thomas J. A.
Published: May 2009

1. The anatomy ofHelodus simplexAg. is described.

2. The skull is found to be holostylic, and to have many characters in common with the skull of the Holocephali, but in some respects is less specialized.

3. The pectoral fins, with their long metapterygium, small propterygium, and fused anterior radials, resemble very closely those of the Holocephali.

4. The pelvic and unpaired fins, and general body shape are found to resemble those of the Holocephali.

5. It is concluded that the Cochliodonts are almost certainly closely related to the ancestors of the Holocephali, and the relatively unspecialized condition of the teeth gives support to the view that the holostylic condition of the jaws is primitive for the group. It is suggested that all the Bradyodonts were holostylic, that the hyomandibular may never have been suspensory, and that they may have diverged from the true Selachii before the hyomandibular played a part in the jaw suspension. The difficulties which this view involves are appreciated.

6. The condition of the ethmoid region ofHelodussupports the view of the nature of the ethmoidal canal put forward by De Beer and Moy-Thomas (1935) rather than that of Allis (1917, 1926, 1934).
Symplectite-bearing Nodules in the Ardgour Marble, Argyllshire
Authors: Drever H. I.
Published: May 2009

Summary and Conclusions

The nodules examined have been shown to contain a variety of minerals and to exhibit certain mineralogical and structural differences from one another or within the nodules themselves. The mineralogical differences serve to separate five definite types of mineral facies. There are also described types transitional between the nodules themselves, and between them and the surrounding rock, grading from types sufficiently aluminous to exclude the formation of wollastonite to less aluminous types in which this mineral is formed.

Owing to insufficiently prolonged variations of the metamorphic conditions equilibrium has not been established, and a remarkable series of replacement structures has been left in the rock by means of which the course of several stages of its metamorphism has been established.

Lack of knowledge concerning the metamorphic conditions previous to changes due to the influence of the surrounding diorite, the isolated character of the nodules and the intricacy of the relationships between the minerals render the origin and metamorphism of these nodules subject to a variety of interpretations. The balance of evidence seems in favour of the one put forward here.
The Formation of the Hydraulic Limestones of the Lower Lias
Authors: Kent P. E.
Published: May 2009

AS a result of a study of the Liassic limestones of the Dorset coast, Dr. W. A. Richardson (1923) concluded that both the limestone bands and the nodules were of secondary origin, and largely displaced the associated marls and shales. Observations made during a study of the Hydraulic Limestone Series (pre-planorbis-johnstoni subzones) in south Nottinghamshire lend support to the hypothesis of concretionary origin, but do not accord with certain other of Dr. Richardson's suggestions.
Larger Foraminifera from the Tertiary of Somaliland
Authors: Nuttall W. L. F. , Brighton A. G.
Published: May 2009

The foraminifera here described were collected by C. Barrington Brown in the course of a survey as geological member of the Anglo-Italian Boundary Commission of Somaliland in 1929–30. We are indebted to him for the opportunity of investigating these specimens and for the use of his unpublished maps and field-reports.
A Mid-Carboniferous Boulder-bed near Settle
Authors: Dixon E. E. L. , Hudson R. G. S.
Published: May 2009

(1) The blocks of limestone in the Bowland Shales of School Share include a variety of rock-types of northern (Yoredale) facies and come from several beds near the Orionastraea Band of the Upper Viséan.

(2) They are a local accumulation at the local base of the Namurian (Upper Bowland Shales; zone of Eutnorphoceras pseudobilingue, E1 and rest, with evidence of some slight erosion, on one of the highest horizons of the Viséan (Lower Bowland Shales; zone of Goniatites spiralis, P2). Their horizon, therefore, is that of the mid-Carboniferous unconformity of Settle and elsewhere.

(3) They mark a comparatively small faunal hiatus (between the newsomi-meslerianum level immediately below and the C. malhamense level above).

(4) Their separation from the parent rocks and their assemblage are not due to tectonic causes. On the other hand, their great size points to some unusual form of transport.

(5) As they occur in a shale series near the Craven Faults they may legitimately be explained as the result of land-slips down s muddy slope from a limestone cliff, probably a fault-scarp raised by the mid-Carboniferous earth-movement.

(6) The circumstances recall those attending the Lower Palaeozoic conglomerates of Quebec. A recent explanation ascribes these to landslips caused by earthquakes from submarine fault-scarps. The School Share landslip may well have been caused by earthquakes, and the scarp from which the blocks were derived may have been essentially submarine.
The Contact Metamorphism and Related Phenomena in the Neighbourhood of Marulan, New South Wales
Authors: Osborne G. D.
Published: May 2009

1. The contact metamorphic effects produced by the intrusion of quartz-monzonite into the Silurian limestone of the Marulan district, New South Wales, are described.

2. The rocks are divided broadly into marbles, hornfelses, skarns, and hybrid diopside-rocks. The first two groups are interpreted as being due to the recrystallization of limestone containing impurities which have reacted with the lime of the sediments to give lime-silicates and certain other minerals. The view is taken that only a very minor amount of pneumatolytic metamorphism followed the main thermal change. The skarns are shown to be due to the metasomatic replacement of recrystallized limestone by magmatic solutions rich in iron and silica, which were also responsible for the deposition of iron-oxides in cracks.

The hybrid rocks are explained as developing from limited marginal assimilation of limestone by the quartz-monzonite magma.
The Geology of Skerryvore, Dubh Artach, and Sule Skerry
Authors: Walker Frederick
Published: May 2009

Skerryvore consists of acid gneiss with dark bands containing biotite and hypersthene. The mica was probably formed by the recrystallization of chloritic matter by heat from an underlying plutonic mass. The islet is cut by a 2 foot north-south dyke of olivine-dolerite.

Dubh Artach forms part of a sill of ophitic olivine-dolerite and is probably of Tertiary age.

Sule Skerry consists of andesine-anorthosite into which dark streaks consisting of hornblende and quartz have been injected at a later date to form a banded gneiss.
The Geology of Jebel Usdum, Dead Sea
Authors: Wyllie B. K. N.
Published: May 2009

The salt of Jebel Usdum is not a product of the Pleistocene Dead Sea, nor of the lake which preceded it (in ? Pliocene time), the waters of which were fresh for a long period and deposited sediments, with a maximum thickness of 1,000 feet or more, which are younger than the salt.
Batholiths of Southern Rhodesia
Authors: Macgregor A. M.
Published: May 2009

THE problem of the formation of the larger masses of granite is receiving considerable attention by geologists at the present time, and it is hoped that the following observations and surmises regarding the granites of Southern Rhodesia may be of more than local interest. Southern Rhodesia forms part of a typical Pre-Cambrian shield and consists, apart from younger formations, of about 74,000 square miles of granite and gneiss intrusive into 13,000 square miles of older rocks. The area has undergone tremendous denudation, which took place mainly during the Pre-Cambrian, and the structures exposed, therefore, are different from those seen in regions where only the peaks of granite masses have been uncovered.

At the outset I wish to thank Mr. H. B. Maufe for permission to draw from the store of information, much of it unpublished, which he has collected in the Geological Survey Office at Salisbury, and also for having the accompanying illustrations drawn in the office. This information includes both petrological and structural data, but it is only the structural aspect of the problem which it is intended to discuss here.
The Tectonic Development of the Western Weald in Lower Cretaceous Times
Authors: Kirkaldy J. F.
Published: May 2009

Modern detailed stratigraphical studies have demonstrated very clearly the long and involved tectonic history of the majority of the main structural units of England. It has been proved that, in certain areas, the thickness and the lithology of the sediments were partly determined by repeated pene-contemporaneous folding along definite axes, and thus it has been possible to trace the gradual growth of some of the main fold lines of the country. The Weald is typical of these areas, whose structure, at first sight simple enough, reveals on closer study much complexity of the minor folding and faulting and also gives evidence of long continued movement along certain lines; movement contemporaneous with the deposition of beds which were involved in the final crescendo of tectonic activity.
The Fish Bed in the Denbighshire Coalfield
Authors: Simpson Henry H.
Published: May 2009

The records of fossil fishes in the Denbighshire Coalfield appear even more scanty than those of the molluscs, and one of the first references1 is to a fish-bed in the roof of the “ Queen Coal ” at Llay Hall Colliery in the north of Denbighshire. This coal is 300–400 feet from the bottom of the Middle Coal Measures, and is known as the “ Premier ” in Flintshire, and in South Denbighshire as the “ Wall and Bench ”. Throughout Denbighshire it is the lowest generally worked seam of the productive measures, as the coals below it are few and, in any case, too thin for profitable operation, except when in association with pottery clay.
An Unusual Occurrence of Myrmekite, and its Significance.
Authors: Hills Edwin Sherbon
Published: May 2009

As early as 1875, Michel-Lévy made what is believed to be the first reference to that intergrowth of plagioclase and vermicular quartz which Sederholm later (1897) named “myrmekite”. In spite of its early recognition and characteristic appearance, however, there was for long no general agreement as to the geological significance or even the exact nature of the intergrowth. It appeared to be confined to the granitoid plutonic and metamorphic rocks, Becke (1913) having categorically stated that it does not occur in “eigentlich vulcanischen Gesteine”, so that it was with interest that the author recently (1932) recorded its occurrence in an Upper Devonian meta-toscanite from Marysville, Victoria. This does not conflict with Becke's statement, since the rock in question has suffered metamorphism by an intrusion of granodiorite, and is therefore not an “eigentlich“ volcanic rock. Nevertheless the mode of occurrence is unique, and the history of the toscanite has been elucidated with sufficient detail to allow one to infer with some accuracy the conditions under which the myrmekite was produced. In the following account, the myrmekite, biotite-quartz-symplektite, and biotite-dactylite in the subjacent granodiorite and neighbouring adamellite bodies, as well as the myrmekite in the meta-toscanite, are described.
Lower Tertiary Rocks in the Province of Berber, Anglo-Egyptian Sudan
Authors: Sandford K. S.
Published: May 2009

In the Abstracts of the Proceedings of the Geological Society of London, No. 1254, of 16th December, 1932, Mr. L. R. Cox described certain siliceous boulders, and their Lower Tertiary fauna, collected for the most part at Hudi, north of the Atbara, by Mr. G. V. Colchester and others. As Mr. Grabham pointed out, the implications that the nature of the boulders and their fauna involve are of supreme importance to the geology of this part of the Nile Basin and, for that matter, of Africa.
The Later Stages of the Cycle of Erosion
Authors: Crickmay C. H.
Published: May 2009

The establishment, toward the end of the last century, of the fruitful conception of the “ cycle of erosion ” carried with it into general currency certain ideas which rest on no real foundation. Although few, nowadays, would be so rash as to doubt the validity of the cycle idea or to question its value as a principle in geology, few can demonstrate any truth in the accepted pictures of the later stages of the cycle. Geographical old age and peneplanation rest on nothing but pure deduction by a few great masters of geography and geology and a blind acquiescence by the rest of us. I say blind advisedly, because only blindness could prevent us from seeing some serious inconsistencies in the picture which have not been generally noticed. These inconsistencies have become increasingly evident in the last ten years. It is time to recognize them.
The Genesis of Oligoclase in Certain Schists
Authors: Turner F. J.
Published: May 2009

The mineralogical changes in green schists and related quartzofelspathic schists of sedimentary origin are discussed, and the following conclusions are reached as to the conditions of formation of oligoclase in these rocks:—

(1) Oligoclase normally appears as a product of dynamothermal metamorphism at relatively high grades such as prevail in the zones of almandine and perhaps kyanite. It is accompanied either by deeply-coloured hornblende, hornblende and biotite, or biotite and muscovite, according to the chemical composition of the rocks in which it occurs.

(2) Sodic oligoclase containing 10 per cent to 15 per cent of anorthite may occur with pale aluminous hornblende in green schists lying within the more strongly metamorphosed portion of the chlorite zone. The rocks in question are low in potash and have been formed by reconstitution, at a higher grade, of chlorite-epidotealbite-schists containing calcite. This oligoclase-hornblende association is not to be confused with the actinolite-epidote-albite-chlorite assemblage which is formed at any grade within the zone of chlorite, by direct reconstitution of basic igneous rocks without change in bulk composition and in the absence of CO2. A slight modification of Tilley’s subdivision of the green schist facies of Eskola is therefore introduced.

(3) A zone of oligoclase representing a grade of metamorphism higher than that attained in the biotite zone, may be recognized for quartzo-felspathic schists of appropriate composition and for many green schists, in areas of progressive regional metamorphism. In the latter case, blue-green hornblende often accompanied by biotite is also present.

(4) Oligoclase or more calcic plagioclase and deeply-coloured hornblende form readily during purely thermal metamorphism of only medium grade in the absence of stress. This accounts for the irregular distribution of both these minerals in districts where purely thermal and regional metamorphism have both occurred during the same period of orogeny.
The Jordan Valley and Judean Highlands
Authors: Willis Bailey , Picard Leo
Published: May 2009

THE nature of the faulting which made the Jordan Valley and separated it from the Mediterranean by the Highlands of Judea has been discussed in a memoir by Professor Bailey Willis, “Dead Sea Problem: Rift Valley or Ramp Valley ? ” Bull. Geol. Soc. Amer., xxxix, 1928, 490–542, and by Dr. L. Picard, Geological Researches in the Judean Desert, Jerusalem, 1931, 108 pp., 3 pl., and map.
The Ballantrae Igneous Complex, South Ayrshire
Authors: Balsillie D.
Published: May 2009

IN the early days of the Geological Survey of Scotland, the rocks of the Ballantrae Igneous Complex were thought to be of metamorphic origin. Thus in the memoir explanatory of sheet 7, scale 1 inch = 1 mile, published in 1869, it is stated that the chief interest attaching to the altered strata of this district consists in the fact that they exhibit certain arrested stages of metamorphic action. But less than ten years after that date the erroneous character of this opinion was made abundantly clear by Professor Bonney.Equipped with experience gleaned in the Lizard, Bonney quickly recognized in Ayrshire a correspondence in the nature of the phenomena. Excellent descriptions were furnished by him of some of the lavas, serpentines, and gabbros, and their true igneous character emphasized.
The Hunstanton Red Rock
Authors: Rastall R. H.
Published: May 2009

IN the January number of this Magazine there appeared a rejoinder by Messrs. Kitchin and Pringle to observations published by myself on their reading of the stratigraphical position of the Hunstanton Red Rock and its relation to the beds above and below. Since the following is intended as an answer to this, it is almost inevitable that it should be written in the first person. For this unavoidable egotism apologies are offered to readers.
The Geology of Marysville, Victoria
Authors: Hills Edwin Sherborn
Published: May 2009

The study of the igneous complex of which the Marysville rocks form a part was begun by the writer in 1928, when he first recognized the acid lavas that form the summit of the Blue Hills east of Taggerty, and practically coincide with the edge of the State Forest Reserve extending eastwards from there among the Cerbereans. Although only a small part of the truly enormous mass of igneous rocks was dealt with at that time, it was clear that interesting stratigraphical and petrological results might be obtained by a more detailed survey, and field work was therefore undertaken at Marysville, some 15 miles south of Taggerty, in 1929.
Notes on the Geology of North Rona
Authors: Stewart Malcolm
Published: May 2009

The island of North Rona bears, on the whole, a close resemblance in structure to the adjacent mainland, with certain distinct minor differences.

The evidence shows that the island probably came under the influences of the quaternary ice, as was suggested by Geikie.
A Bibliography of the Tectonics of England and Wales
Authors: Rastall R. H.
Published: May 2009

FOR more than twenty-five years the compiler of this bibliography has been deeply interested in the tectonic history of the British Isles: for the greater part of this time he has also been struck by the absence of any adequate and annotated treatment of the subject, since the appearance of the third edition of Jukes-Browne's Building of the British Isles, 1911. (The so-called 4th edition of this work, dated 1922, appears to be merely an unrevised reprint of the 3rd edition.) In 1929 this want was in part supplied by the publication of The Physiographical Evolution of Britain, by Dr. L. J. Wills. Even in this admirable work, however, the stress is on physiography rather than on tectonics, and many of the more important writings on this side of the subject are not referred to. In the Handbook of the Geology of Great Britain, which appeared in the same year, the exiguous section on “Morphology” includes no bibliography, while the whole scheme of treatment is in the main palaeontological, and little help on the tectonic aspect is to be obtained from the text of most of the sections. The present publication may in a sense be regarded as a supplement to that work.
On the Structures of the Dermal Ethmoid Shield of Osteolepis
Authors: Westoll T. Stanley
Published: May 2009

The structure of the fronto-ethmoid shield ofOsteolepis macrolepidotusAg. is described fully for the first time, and the homology of the dermal bones is discussed. The most interesting feature is the recognition of the existence of a sensory-canal bone bearing teeth in the position of the premaxillary of Tetrapods, with which it is shown to be homologous; the nomenclature of the equivalent bones suggested by Säve-Söderbergh is discussed and revised.

The presence of a continuous cosmine sheet overlying several bones is emphasized, and the problem of growth of such a combination is brought out. It is shown that the problem can be solved by extensive resorption and redeposition of cosmine, and this hitherto unnoticed change is demonstrated in a number ofOsteolepids and in some Dipnoi. The results of the resorption are to free the bones of the head from the cosmine, and thus to expose the top of the true bone ; the new characters are those usually associated with different genera, usually placed in distinct families.

Finally it is noted that the resorption involves a general chemical change affecting cosmine all over the body, which it is suggested may be due to the release of an internal secretion, the whole process of resorption and redeposition of cosmine being cyclic and almost certainly seasonal, growth being therefore a seasonal change.
On the Mechanics of Mountains
Authors: Jeffreys Harold
Published: May 2009

It appears that the geophysical approach to the problems of crustal dynamics leads to a theory of mountain formation that covers the main features of the formation of nappes and is in general agreement with other geological evidence. The chief novelty is in the recognition of the importance of the spreading under their own weight of the rocks uplifted as a result of crustal shortening.
On Corundum-Spinel Xenoliths in the Gabbro of Haddo House, Aberdeenshire
Authors: Read H. H.
Published: May 2009

IN the neighbourhood of Haddo House, between Methlick and Ellon, some 20 miles north of Aberdeen, there is a considerable body of gabbro that has been named the Haddo Mass. This intrusion is later than the general metamorphism of the Dalradian country-rocks and, from its resemblance to certain dated intrusions, earlier than the local Middle Old Red Sandstone. It belongs, therefore, to the Younger Gabbro portion of the Post-Movement Phase in the igneous history of North-East Scotland.
The Genetic Relationships of Pegmatites, Aplites, and Tin Veins
Authors: Derry D. R.
Published: May 2009

From the conclusions regarding the formation of complex pegmatites from the field and microscopic evidence, the following sequence of events is suggested:—

Towards the end of the solidification of a granite magma a liquid remains, having the general composition of a common pegmatite, but with small quantities of sodium and some rarer elements. By squeezing during crystallization this magma is separated into two distinct parts, one of which forms common aplite dykes. The other, more aqueous portion, when tapped by fissures, solidifies more slowly to form dykes, sills, or stringers of common pegmatite. During this solidification the albite (in solution), together with rare elements and their compounds, is concentrated in the remaining liquid portion, which now contains a very high proportion of water. This aqueous solution begins to migrate up the dykes or sills of common pegmatite, possibly even before the latter has completely solidified, showing a preference for the foot-wall, and begins to replace the earlier minerals, The first stage is the replacement of potash felspar, either microcline or orthoclase, by albite. Later there is a replacement of albite and sometimes of earlier minerals by spodumene, lepidolite, cassiterite, tantalite, etc. Cassiterite, possibly due to being carried in combination with a volatile element tends to be deposited in the uppermost part of the dyke or sill, where, however, some albite replacement has always preceded it.
Notes on Brimstone Hill, St. Kitts
Authors: Trechmann C. T.
Published: May 2009

BRIMSTONE HILL, 779 feet high, on the north-west side of the island of St. Kitts, or St. Christopher, about a third of a mile from the sea, lies about 2½ miles south-west of Mount Misery, the culminating point, which is said to be 3,711 feet high and to have a crater lake. Several other peaks of the island rise to over 1,000 feet, and to the south-east of Mount Misery another weathered cone is Mount Olivees, 2,781 feet high. About 12 miles to the north-west of St. Kitts is the Dutch island of St. Eustatius, or Statia, a dormant volcanic cone about 594 metres high on the south-west side of which great slabs of white sedimentary rock, called the White Wall, are seen tilted up against the side to a height of 315 metres. Further still to the north-west is the volcanic cone of Saba. South-east of St. Kitts, and nearly adjoining it is Nevis, which consists of a central cone and several subsidiary craters. These islands—Saba, St. Eustatius, St. Kitts, and Nevis—lie in a slightly curved line in a north-west and south-east direction.
The Gault at Compton, Surrey
Authors: Lea F. A.
Published: May 2009

EXCAVATIONS for a new road in Whiteacre Copse, north-west of Compton, Surrey, have afforded an exceptionally good opportunity for collecting fossils from the Lower Gault of this district. Unfortunately, though the cutting passes through the whole thickness of the formation, it is very shallow in the higher parts, and no specimens could be obtained from the Upper Gault. But three unrecognizable impressions of ammonites were seen at the base of this Upper Gault. The tilt of the strata here is 30° N.
Quartz-Dolerite Pebbles (Whin Sill Type) in the Upper Brockram
Authors: Dunham K. C.
Published: May 2009

THE finding of a small pebble of fine-grained quartz-dolerite in an exposure of the Upper Brockram in George Gill, near Appleby, by Professor Arthur Holmes in 1925 and its identification with the rock of the Whin Sill led to the direct establishment of the timeof injection of the Whin Sill and related dykes as post-Carboniferous and pre-Upper Brockram (1928, pp. 532–4). Since 1925 parties of students from the Durham Colleges’ Department of Geology have made each year a careful search for similar pebbles not only in the George Gill exposures but in a number of others in the Brackenber Moor neighbourhood. These efforts have not been rewarded with any success until the present year, when a party under my guidance made a thorough examination of the George Gill Brockram and Mr. A. R. Leathley, of Hatfield College, had the good fortune to hammer out a pebble of doleritic aspect.
New Miocene Faunas from Cyprus
Authors: Reed F. R. Cowper
Published: May 2009

AN interesting collection of Tertiary fossils has recently been sent me for determination by Mr. C. P. Manglis, Manager of the Mitsero mines in Cyprus, who has collected them from the neighbourhood of these mines. Mitsero village stands near the head of a valley running down the north side of the Troodos mountains to the plains of Morphou and is described by Messrs. Cullis and Edge (1, p. 38) as standing on volcanic rocks close to the junction of the pillow-lavas with the overlying marls and limestones, while “ behind it is a bold sedimentary escarpment breached by the valley just mentioned and culminating in Koroni Mountain (2,140 feet), 1½ miles to the westnorth-west ”. The Koronia Limestone, the outcrop of which on the Evrykou road the author visited in 1929 (2, p. 443), occupies the top of the escarpment, as shown on a map sent to me by Mr. Manglis of the immediate district (scale, 1: 10,000) from the village of Kato Moni on the north-west to the village of Mitsero on the south-east. The position and age of the Koronia Limestone have been uncertain owing to the lack of definite fossil evidence, though the author (2a, p. 251) was inclined to put it in the Miocene rather than the Pliocene on the strength of a species of Cerithium which he discovered in it. The majority of the fossils in Mr. Manglis’s collection come from this limestone and provide ample evidence of its Miocene age.
The Origin of Igneous Rocks
Authors: Holmes Arthur
Published: May 2009

THE leading problems presented by igneous rocks are:—

(a) the nature and sources of the primary magmas;

(b) the mechanics of magmatic intrusion and emplacement; and

(c) the processes which have brought about the manifold diversity of igneous rock-types.
The Millstone Grit of Gower
Authors: Dix Emily
Published: May 2009

THE Millstone Grit described in this paper forms a belt of country about a mile wide, stretching from west-north-west to east-south-east across the north of the Gower Peninsula. Reference is also made to small areas of Millstone Grit preserved in synclines at Oxwich and Porteynon on the south coast of Gower. These areas form the most important outcrops of this formation on the south of the South Wales Coalfield. Further east the Millstone Grit is thinner and it is not exposed for some miles to the east of Swansea Bay, as it is concealed by Mesozoic rocks.
Syntexis and Differentiation
Authors: Brammall Alfred
Published: May 2009

PETROGENIC problems concern the processes and effects of adding to magma, or subtracting from it, rock-forming substance in general. Increment or loss of silica alone entails relatively simple mineralogical consequences. The more intricate problems concern the addition of associated material (notably alumina, the Ro-oxides, alkalies, and fluxes) in varying relative proportions, and at any stage in the evolution of rest-magma. These additions tend either to promote, counter, or otherwise modify the prevailing trend of differentiation in magma thus augmented.
Notes on the Geology of Sula Sgeir and the Flannan Islands
Authors: Stewart Malcolm
Published: May 2009

Sula Sgeir consists of hornblende-gneiss with occasional biotite and augite. The whole is intersected by small pegmatite veins which merge along the borders into the gneiss. Though evidence is small, it seems probable that the island, together with North Rona, came under the influences of the Quaternary ice.

The Flannan Islands consist also of hornblende gneiss, biotite being a fairly common accessory. Numerous and varied pegmatite Veins occur throughout the islands, and in certain cases have affected the foliation of the gneiss. Owing to the proximity of the islands to the Lewis and the Harris, and the presence of adeposit of cemented sand on Eilean Ghobha, it seems probable that the Quaternary ice also reached these islands.
Gutenberg's Fliesstheorie; a Theory of Continental Spreading
Authors: Lake Philip
Published: May 2009

GUTENBERG is not a geologist but, as a geophysicist, he is directly interested in several of the broader questions of geology. He has been impressed by the simple way in which Wegener’s drift theory seems to solve many geological problems, but he finds it impossible to accept that theory in its entirety. He has, therefore, tried to formulate another theory which is more in accordance with geophysical data, and which still solves the same geological problems. “Continental Spreading,” a name suggested by Dr. Harold Jeffreys, expresses very clearly its dominant feature.
The Petrology of the Warren House Series, Malvern
Authors: Platt John I.
Published: May 2009

THE Warren House Series consists of lavas which belong to a sodic suite, being rhyolites, keratophyres, and spilites. The rhyolites have a fine-grained micrographic groundmass, and some contain phenocrysts of quartz, orthoclase, anorthoclase, and plagioclase felspar. Epidotization of the rocks has occurred, but it is the felspathic and femic constituents of the groundmass which have suffered alteration and not the felspar phenocrysts, the action not being intense enough to affect the latter. The keratophyres consist essentially of small lath-shaped albite crystals which give a trachytic texture to the rock. The spilites are more basic, vesicular, and variolitic or sub-ophitic in texture, while some of them show pillowstructure in the field. The keratophyres and the spilites also exhibit varying degrees of epidotization. Pyroclastic rocks are not very common, but a few interesting varieties have been noted. Intrusions of dolerite occur within the lavas. One type is an ophitic dolerite, which when fresh probably contained olivine. Another type is now an epidiorite. Both these types have been epidotized, the epidiorite to such an extent that it passes into an epidote-uralite rock in places.
Dolerites Associated with the Karroo System, South Africa
Authors: Daly Reginald A. , Barth Tom F. W.
Published: May 2009

—The field impression of a high degree of uniformity in the composition of the intrusive Karroo dolerites over a vast area is confirmed by new chemical and microscopical studies. The pyroxene characteristic of the dolerites is a typical pigeonite, which, however, does not display any twinning on (100). The plagioclase is potash-free, usually a labradorite, but it has been observed that a homogeneous crystal of plagioclase may be in twin position to another homogeneous crystal of a very differently composed plagioclase. The close resemblance of the doleritic liquid to the artificial liquid taken by Bowen to represent basaltic liquid is noted, and his conclusion that pyroxene and feldspar should crystallize simultaneously in natural basaltic liquid is confirmed.

Conceivably the doleritic liquid was quite original and not a differentiate of any earlier liquid. However, analogies like those with the tholeiites and similar hypabyssal rocks of Great Britain suggest that in South Africa, as in Great Britain, the liquids of these hypabyssal rocks were derived from the slightly more femic plateau-basalt.

On that assumption the question of the mode of differentiation arises. The fractional crystallization of plateau-basalt, as now described by Bowen and other leaders, does not appear competent to explain the abnormally low soda of one of the analyzed dolerites, nor the excess of soda and total alkalies in plateau-basalt respectively over the soda and total alkalies of the Karroo dolerite. Further, the settling-out of early olivine does not explain the excess of (total) FeO in plateau-basalt over the (total) FeO in the Karroo dolerite. The actual relations indicate the need of renewed examination of the theory of magmatic differentiation by crystal-fractionation. In any case many more data are required before it is possible to decide upon the precise relation of the Karroo dolerite to a parental magma. Possibly such additions to knowledge may annul present difficulties in the way of accounting for the composition of the dolerite.
Species of the Genus Dimorphoceras in the Bowland Shales
Authors: Moore E. W. J.
Published: May 2009

The genus Dimorphoceras was instituted by Hyatt, the genotype being Goniatites gilbertsoni (Phillips). The shells are involute and compressed, having the umbilicus very small or closed. The test shows fine lines of growth and a deep hyponomic sinus. Dimorphoceras is differentiated from other goniatites by having either one or both of the sutural lobes sub-divided by a small subsidiary saddle. Specimens are not generally abundant; and owing to the feeble ornamentation of the test, distinction between species is impossible unless uncrushed specimens showing sutures are obtained.
An Association of Afwillite with Spurrite
Authors: Tilley C. E.
Published: May 2009

The mineral afwillite (3CaO.2SiO2.3H2O) is so far recorded only from the Kimberley Mines (Parry and Wright, Min. Mag., 1925, p. 277), where it occurs in association with natrolite, apophyllite, and calcite in a dolerite inclusion in kimberlite. Its occurrence with markedly different associations is sufficient warrant for a short record. Examination of the mineral associates of spurrite of the contact zone of the Scawt Hill dolerite Co. Antrim has revealed a second occurrence of afwillite, lining a cavity in a thin calcitic crust covering a spurrite contact rock.