bluuebunny/crossref_metadata_2025 huggingface dataset:
Scandinavian Boulders at Cromer
Authors: Madsen Herr Victor
Published: October 2009

During a visit to England in the autumn of 1891, I took the opportunity of making a short excursion to Cromer in order to study the interesting geological facts presented in the well-known cliffs near that village.

On my walks along these cliffs my attention was especially devoted to the boulders which occur there, for I thought it possible to find some which might with certainty be referred to definite localities in Scandinavia. The greater number of the boulders there originate indeed, as I expected, from disturbed portions of the Cretaceous strata which underlie the Drift in the vicinity of Cromer, so that it is only a few of the boulders which are likely to be of Scandinavian origin, and of these again only a small number can be definitely referred to their parent localities.

Among the boulders on the shore a little west of Cromer I succeeded in finding a ‘porphyry’-boulder which I supposed had been derived from the south-eastern part of Norway, and this supposition was subsequently confirmed by Herr K. O. Björlykke, of the Norwegian Geological Survey, to whom I showed the boulder and who referred it to the neighbourhood of Christiania.

This boulder measures
about 4½ × 3½ × 2 inches. The ground-mass is rather decomposed and of a grey-violet colour; in it are disseminated crystals of felspar which, on fresh fracture, show the same colour as the groundmass, while those on the surface of the boulder have become somewhat paler by decomposition. The sections of
Notes on the Geology of the District West of Caermarthen
Authors: Roberts T.
Published: October 2009

In a paper published in the Society's Journal in the year 1885 a complex synclinal of Lower Palaeozoic rocks occurring in the neighbourhood of Haverfordwest was described. Owing to the occurrence of a fault at the northern side of that synclinal, no strata of Arenig age were noticed in the paper, the oldest Ordovician beds referred to being the
Didymograptus Murchisoni
-shales below the Llandeilo Limestone in the neighbourhood of Narberth, at the south-eastern end of the synclinal. It seemed important, therefore, to work the strata lying east of Narberth in order to try and discover Arenig Beds in the district between that town and Caermarthen. This was accordingly done in some of the vacations between 1886 and 1890, and a complex anticlinal was discovered lying north-east of the Haverfordwest synclinal, having its oldest beds exposed north of Whitland. The accompanying map shows the general distribution of the beds in this anticlinal, no attempt being made to trace accurate boundary-lines ; but two approximate boundaries are drawn at the top of the
Tetragraptus
-beds (to be presently described) and along the line of outcrop of the Llandeilo Limestone respectively, in order to show the general distribution of the strata and the nature and direction of the anticlinal. The beds may be described, in ascending order, as follows :—

1. Tetragraptus-beds.—These beds consist of alternating conglomerates, shales, and grits, seen at Talfan, :pen-parc-uchaf, and probably near Whitland Abbey, all places lying generally north of Whitland. The shales have yielded graptolites, kindly determined by
On Inclusions of Tertiary Granite in the Gabbro of the Cuillin Hills, Skye; and on the Products resulting from the Partial Fusion of the Acid by the Basic Rock
Authors: Judd John W.
Published: October 2009

1.
The Literature Of Inclusions In Igneous Rocks
.

The striking results of extreme contact-metamorphism, displayed by fragments of rock which have lain for a time in the bath of a molten igneous magma, have been frequently described by geologists and petrographers. Among sedimentary materials which have been thus acted upon, we may refer to the more or less perfectly vitrified products formed from arenaceous rocks (
verglaster sandstein
); the greatly altered and highly crystallized forms of argillaceous masses—so often mistaken for basalts, befbre the application of the microscope to their study—(
jaspisschiefer, kieselschiefer
, ‘phthanite, lydite, hydrotachylyte,’ etc. of different authors); and the calcareous or dolomitic rocks, so wonderfully rich in beautifully crystallized minerals that have resulted from the action of molten lavas or fragments of limestone entangled in them. Such extreme results of contact-metamorphism may be studied, either in the localities where the operations have taken place, as at Monzoni in the Tyrol; or among the fragments thrown out from volcanic vents, as at Monte Somma and the Eifel.

The phenomena displayed, when fragments of an igneous or other crystalline rock are caught up and enveloped in a molten material of different chemical composition, have received no less attention from petrographers. Some of the results of this extreme action have been regarded as so anomalous that they have given rise to much discussion. Without attempting to make an exhaustive list of works on this question, I may refer to the following memoirs as especially bearing on the point discussed in the present paper.
Geological Notes on Certain Islands in the New Hebrides
Authors: Frederick G. C. , Hinde George Jennings , Teall J. J. H.
Published: October 2009

So far as can be judged at present from the soundings obtained, it appears that the New Hebrides are probably situated on a bank lying from 350 to 400 fathoms below the surface of the ocean and running in a N.N.W. and S.S.E. direction, with a deep valley between it and New Caledonia. The only soundings obtained between these two groups are 2375 and 2730 fathoms respectively, the former within a short distance of the New Hebrides.

1.
Tanna
.—On the east side of this island is situated a volcano which has been in constant activity for many years, and on ascending its sides one is struck by the fact that so little lava is to be seen. The cone itself, which rises to a height of nearly 1000 feet above the sea, appears to be formed entirely of more or less fine ash, and there are no signs of any lava-flow.

In November 1890 the crater appeared to be about 300 feet deep, and was split into two nearly equal parts by a kind of rocky wall or partition which rose to a height of about 100 feet from the bottom.

There were five fire-holes, three on one side and two on the other side of the partition, where the molten materials were bubbling and pulsating with a subdued roaring sound; but every few minutes a tremendous explosion took place, throwing up the molten seoriæ, etc., to heights varying from 100 to 300 feet above the summit of the crater.
On the Microscopic Structure of the Wenlock Limestone, with Remarks on the Formation generally
Authors: Wethered Edw.
Published: October 2009

I. Introduction

The general features and fossils of the Wenlock Limestone have been described by several geologists, but I am not aware of any endeavor to make a systematic examination of the microscopic structure. The value of such work has been greatly underestimated; for investigations which I have made show that, although much information as to the formation and structure of the rock may be gained by observations made without the assistance of a microscope, yet the use of this instrument brings into view important facts which are not perceived by the unassisted eye.

In this paper I do not attempt an exhaustive enquiry; to do this it would be necessary to make several visits to the localities from which specimens for examination were collected, and this I have been able to accomplish only in the case of the Wenlock Limestones exposed within a convenient distance from Cheltenham. I have therefore selected what I regard as typical sections of the limestone in the neighbourhood of May Hill in Gloucestershire, and in the adjoining portion of the county of Hereford.

The procedure has been to take samples from several beds in each exposure of the rock, and to grind down the usual thin sections for examination under a microscope. These I prepare myself, and I mention the fact because it seems to me important for this reason: very many slides require to be made for a paper like the present one, and each must be adjusted, with regard to actual thinness,
On the Affinities of
Anthracoptera
and
Anthracomya
Authors: Hind Wheelton
Published: October 2009

Part
I.
The Affinities Of Anthracoptera

The first mention of these shells is by Sowerby in Prestwich's memoir on the geology of Coalbrookdale, where four species are figured—one as
Modiola
, a second as
Mytilus
, and the other two as
Avicula
. These were hesitatingly referred to
Myalina
or
Avicula
by Salter, in ‘Iron Ores of South Wales,‘ Mem. Geol. Surv. 1861, where in a footnote (p. 230) he hazards the conjecture that they may belong to
Anthracomya
, a genus then described for the first time to contain shells previously referred to
Unio
. In 1862, in the memoir on the ‘Geology of the Country round Wigan,’ he proposed the name
Anthracoptera
for certain shells previously described and figured as
Avicula, Modiola
, and
Myalina
; he there detailed the specific characters and gave a diagrammatic woodcut of the genus.

In the Supplementary Chapter to ‘Acadian Geology,’ 1860, Sir J. W. Dawson proposed the name
Naiadites
to include all Coal Measure shells; he then figured no shell referable to this genus, although Salter, in his paper ‘On some fossil Crustacea from the Coal-measures of British North America,’ Quart. Journ. Geol. Soc. vol. xix. (1863) p. 79, figured a shell,
Anthracoptera carbonaria
, evidently correctly, but erroneously identified it with Dawson's figure (fig. 42, p. 204), which really represents an
Anthracomya
. Subsequently, in the 2nd edition, in 1868, Sir J. W. Dawson showed that he believed
Naiadites carbonaria
to be synonymous with
Anthracoptera carbonaria
, Salter, and
Naiadites lœvis
with
Anthracoptera lœvis
, the figures given resembling
Anthracomya
rather
On a Sauropodous Dinosaurian Vertebra from the Wealden of Hastings
Authors: Lydekker R.
Published: October 2009

In an earlier volume of this Journal Mr. Hulke figured and described certain vertebræ of a large Sauropodous Dinosaur from the Wealden of the Isle of Wight, under the name of
Ornithopsis
, that name having been substituted for
Eucamerotus
, which the author had previously intended to use on account of its being the earlier. I have subsequently had reason to indicate that the name
Ornithopsis
itself must, for the same reason, yield to
Hoplosaurus
, which was proposed by Gervais on the evidence of a tooth of the same animal.

In addition to
Hoplosaurus armatus
and the still larger
Pelorosaurus Conybeari
, there is evidence of another large Sauropodous Dinosaur in the Wealden, now known as
Morosaurus brevis
(Owen). Up to the present time it has, however, been impossible to compare adequately
Hoplosaurus armatus
with
Morosaurus brevis
, owing to the circumstance that while the former is known by teeth, cervical and dorsal vertebræ, and the pelvis, the latter is mainly represented by the bones of a forelimb and some caudal vertebræ an imperfect centrum of a late dorsal vertebra having been also tentatively assigned to it.

Recently Mr. P. Rufford, of Hastings, has sent to the British Museum (Nat. Hist.) for identification an imperfect dorsal vertebra of a large Sauropodous Dinosaur from the Wealden of Hastings, which has enabled the desired comparison to be made.

I would observe in the first place that the specimens which must be regarded as the types of
Cetiosaurus brevis
are four associated caudal vertebraæ from the
On the Dwindling and Disappearance of Limestones
Authors: Rutley Frank
Published: October 2009

There are probably few instances in nature in which limestone–beds are so protected that water cannot gain access to them. A limestone-bed to which water charged with carbonic acid gains access becomes gradually dissolved, and, furthermore, the solvent action of humus acids must also, in some cases, be taken into account. The question whether such a bed will completely vanish is one which involves merely the magnitude of the bed, the duration and energy of the solvent action, and the freedom of the limestone from foreign matter of a more or less insoluble nature. If unlimited time be conceded, there seems no reason why very thick beds of limestone should not wholly disappear; at all events thin ones may easily do so.

The formation of caves, chasms, and pinnacles, the general sculpturing of limestones, and the thick deposits of calcareous tufa which occur in many localities sufficiently attest the activity with which the erosion of limestones has been carried on in recent times, and there appears to be no reason to doubt that similar work has been constantly in progress during bygone ages, under like conditions. Given like conditions, the greater the age of any limestone-deposit, the more will it have been wasted away. Granted sufficient time, its disappearance is inevitable.

Any argument adduced in support of the probable disappearance of very ancient beds of limestone may be applied with additional force in the cases of rock-salt and gypsum.

Where limestones occur at the surface, their erosion is due not
Notes on Dartmoor
Authors: McMahon C. A.
Published: October 2009

The geology of Dartmoor has already furnished material for a somewhat extensive literature; but, as many points in connexion with this region are still in dispute, the discussion of the subject cannot be considered as finally closed. The view advocated by De la Beche was that the granite of Dartmoor was intrusive in the adjoining sedimentary rocks, and that the metamorphism exhibited by the Culm and Devonian beds for a certain distance round the margin of the granite was due to the contact-action of the heated eruptive rock. Quite recently, however, this view has been challenged by Mr. W. A. E. Ussher, F.G.S., of the Geological Survey, and it is alleged by this observer that “the genesis of the Devon and Cornish granites .... resulted from the metamorphism
in situ
of pre-existing rocks of pre-Devonian age, which had in a rigid state exercised an obstructive influence on the N. and S. movements, and had thereby produced great mechanical effects on the surrounding strata prior to the alteration of the latter” (p. 219). The result of this dynamic action is spoken of as ‘fusion’ (pp. 207, 217); the “fusion and subsequent consolidation would appear to have been effected
in situ
” (p. 217), and “the consolidation of the granite in its present aspect may therefore be regarded as post-Carboniferous, or possibly coeval with the later stages of Carboniferous deposition” (p. 218).

If I understand Mr. Ussher aright, the north-and-south movement did not set up any material metamorphic change in the Culm and
On Raised Beaches and Rolled Stones at High Levels in Jersey
Authors: Dunlop Andrew
Published: October 2009

The valuable paper of Prof. Prestwich on ‘ The Raised Beaches, and ‘ Head ’ or Rubble-drift, of the South of England,’; which has thrown so much light on the Quaternary geology of that area, is especially interesting to me. for in Jersey there are well-marked post-Glacial deposits which have hitherto received little attention from geologists. The brick-clay or brick-earth, which covers so much of the island, I have already described, and I am now desirous of directing attention to the higher raised beaches, and to other evidences of alteration in the height of the land, more especially of considerable and probably long-continued subsidence.

Several writers have already described or mentioned the low-level raised beach, found in places all round the island —as, for example, Mr. Trevelyan, Lieut. Nelson, Prof. Prestwich, and Father Noury The last-named geologist, however, seems to doubt its being a raised beach in the proper sense of the term. Mr. T. W. Danby, on the authority of the late Dr. M. Bull, mentions a raised beach on the west coast of the island, said to be about 100 feet above the level of the present beach and in Latham and Ansted's work on the Channel Islands it is stated that a raised beach about 30 feet above the present mean level of the sea was laid bare during the construction of Fort Regent.

The most elevated raised beach which I have as yet observed is that on the top of the soutehrn part of the
On Composite Dykes in Arran
Authors: Judd J. W.
Published: October 2009

I. Definition and Classification of Composite Dykes.

Those dykes which are filled with materials differing one from another in chemical composition or mineralogical constitution may be conveniently spoken of as ‘composite dykes.’ In some cases the diverse rocks found in the same dyke may be only varieties of a single type, exhibiting dissimilarities in the proportions or arrangement of their several mineral constituents; but in other cases two or more rock-species, absolutely distinct, may be found to enter into the constitution of a single dyke. A careful study of these composite dykes shows that they fall naturally into two classes, as follows :—

(A)
Composite dykes in which a differentiation has gone on in the material that has filled the dyke
.—This differentiation usually results in the separation, or partial separation, of the vitreous base of the rock from the crystals scattered through it ; but in some cases the crystallizing process, acting selectively within the dyke, has led to the formation of rocks which, in different parts of the dyke, show marked variations in chemical composition or texture, and even in mineralogical constitution. The separation of the glassy from the crystalline materials in this variety of composite dykes takes place in various ways ; the vitreous material may form lateral bands (‘ selvages ’) or irregular patches, or it may fill ‘ amygdaloidal’ cavities. But in all cases there is found to be a more or less perfect gradation from the one type of rock to the other.

(B)
Composite
Observations on the Affinities of the Genus
Astrocœnia
Authors: Tomes Robert F.
Published: October 2009

Researches recently made relative to the structure of certain undoubted
Astrocœniœ
, having for their primary object the better understanding of the supposed species of the genus obtained from the Glamorganshire Conglomerate, have been productive of results which are to a great extent unexpected, and which will render imperative a complete modification in the classificatory position of the genus.

Before recording the examinations which have led to these results, it is desirable that I should make a brief survey of some part of the literature relating to the genus. Commencing with its definition by the original describers, MM. Milne-Edwards and Haime, which appeared in the ‘ Annales des Sciences Naturelles ’ in 1848, I transcribe in full their own words :—

“ Ce genre a un polypier massif, beaucoup plus dense que celui des Stylocœnies. Los cloisons sont proportionnellement épaisses, et on ne distingue jamais à l‘angle des calices de tubercules columnaires. Enfin, la columelle est en général très peu saillante. Sous tous los autres rapports, les Astrocœnies ne diffèrent pas du genre précédent [
Stylocœnia
] ; elles se séparent comme lui des Stylines par les calices polygonaux ; des Stéphanocœnies, par l'absence de palis ; des Phyllocœnies, des Dichocœnies et des Hétérocœnies par la columelle styliforme.”

After a few words relative to the distribution of the several species constituting the genus, the same authors continue :—“ Parmi celles que nous avons pu étudier, de manière à les caractériser suffisamment, les unes présentent des calices en polygones irréguliers et de grandeurs un
Description of a New Genus of Madreporaria from the Sutton Stone of South Wales
Authors: Tomes Robert F.
Published: October 2009

In vol. xlii. (1886) of this Journal is a critical and detailed description of a coral from the Sutton Stone of South Wales, which is there described as
Astrocænia gibbosa
, Dunc. The paper in which it appears is, I need hardly say, by the late Prof. Duncan. But the specimen there described is not the type of the species, and, indeed, I do not know whether it had ever been specifically determined before the publication of the paper above alluded to; certainly there is no mention of it in the pages of the volume of the Palæontographical Society, in which
Astrocænia gibbosa
was first characterized. It was collected by E. B. Tawney, is now in the Museum of the Geological Society, and after having been cut through horizontally and polished, was described by Prof. Duncan in the paper above mentioned.

A very hasty examination of the polished surface figured by Prof. Duncan sufficed to assure me that there were characters which neither he nor I had attributed to that or any other species of coral from the Glamorganshire Conglomerate. Some of the elongated or double calices presented much the appearance of fissiparous division, and I was anxious to examine them by means of thin sections and transmitted light, and at the same time to learn something of the structure of another part, the (apparently) much thickened walls. In accordance with my wish, the Society had a section made and submitted to me for examination. It consists of a slice taken
On the Sequence of Perlitic and Spherulitic Structures: a Rejoinder to Criticism
Authors: Rutley Frank
Published: October 2009

In a paper on ‘The Shap Granite and the Associated Igneous and Metamorphic Rocks’ the authors, Messrs. Harker and Marr, did me the honour to refer to certain statements made by me in the year 1884 with regard to the microscopic structures of a perlitic felsite, associated with the Coniston Limestone where it crosses the northern end of the Long Sleddale Valley in Westmoreland.

The opinion which I then expressed was that “spherules may cause the devitrification of a rock after it has solidified and after perlitic fission has supervened.” A list of the structures, present in the section examined, was also given in the following order of sequence:—1. Fluxion-bands. 2. Perlitic structure traversing these bands. 3. Minute spherules constituting the whole rock, so far as spherules can do so, and passing through the perlitic fissures. 4. Subsequent fractures. 5. Formation of quartz-veins along these lines of fracture.

In the following year (1885) I again referred to this rock in one of the Memoirs of the Geological Survey, remarking that “Spherulitic devitrification followed the development of the perlitic structure.”

Messr. Harker and Marr, after alluding to the microscopic drawings of tis rock published in Mr. Teall's ‘British Petrography’ (1888) pl. xxxviii. and to my own remarks, namely those which have just been cited, made the following observation:—“ The latter author has expressed the opinion that the spherulitic structure is here an effect of devitrification sudsequent to the perlitic ranking; but we are unable to see that he has given any
On some Bryozoa from the Inferior Oolite of Shipton Gorge, Dorset. Part II.
Authors: Walford Edwin A.
Published: October 2009

The Cheilostomatous Bryozoa have hardly been recognized with certainty in the Jurassic series, and Haime mentions two forms of the Escharidæ in his monograph with considerable dount and without illustration. In the little group dealt with in this paper are mingled both cheilostomatous and cyclostomatous features, but the former predominate, and, for the present, itt is desirable to place the group there. We thus open a field for investigation which will trench deeply into the ground hitherto occupied by the Cyclostomata.

Messrs. Waters, Vine, and Ulrich have written of cheilostomatous structure in Palæ fossils; the English Jura now leads backward also the relations of this sub-order, and we need to scasn this distant horizon of bryozoan development for signs suffcient to guide us on our way.

After I had read Part I. of my papaer in 1889 I withdrew for further study two of the species related to those that I am about to described. So many of their features were dissimilar tot he Entalophora among which I had placed them, similar as they were in general aspect, that it seemed necessary to find a place for them elsewhere.

The characters of the two sub-orders Cheilostomata and Cyclostomata merge as we pass backward in time. This merging the accessory organs of the genus and species here decribed and figured will illustrate. Mr. A. W. Waters has paved the way to the same conclusion in a recent paper. He writes:—“In the Cretaceous Melicertitidæ the characters are in the main chilostomatous united
The Vertebrate Fauna collected by Mr. Lewis Abbott from the Fissure near Ightham, Kent
Authors: Newton E. T.
Published: October 2009

I. I
ntroduction

The remains of vertebrate animals during the last two or three years, with much care and in large numbers, by Mr. Lewis Abbott, from one of the fissures in the Kentish Rag near Ightnam, in Kent, have been from time to time brought to me for examination and identification. The outcome of this study of many hundreds of specimens is contained in the present paper.

The occurence of Pleistocene mammalian remains in Kent is well known, and Mr. W. Topley has noticed such remains in the brick-earth filling long chasms in the Kentish Rag, which he alludes to as ‘Pipes,’ varying much in size and very numerous in the neighbourhood of Maidstone. In one such chasm at Boughton, 3 miles south of Maidstone, numerous bones were found by Mr. Braddick many years ago, and Dr. Buckland was of opinion that these ossiferous cavities were ‘caverns.’ So far as I have been able to ascertain, this is the only recorded instance of mammalian remains being found in what appear to be caves or fissures in the Wealden area. The species found at Boughton are enumerated by Prof. Boyd Dawkins in his paper on the ‘Distribution of the British Post-Glacial Mammals,’ namely
Hyæna spelæa
[=
H. crocuta
],
Cervus tarandus
,
C. elaphus
,
Bos primigenius
,
Equus caballus
,
Rhinoceros tichorhinus
, and
Elephas primigenius
; all these species, with the exception of
Bos primigenius
, have been found in the Ightham fissure. The larger fossil mammalia of the South-east of England have received much attention at the
On the Relations of the Basic and Acid Rocks of the Tertiary Volcanic Series of the Inner Hebrides
Authors: Geiki Archibald
Published: October 2009

I. Introduction

Before entering upon the special subject of the present paper, I wish to be permitted to make certain personal explanations which appear to me to be necessry on this occassion. Having in my early years had the good fortune to spend much time among the Western Islands of Scotland, I was soon fascinated by the geological features of that picturesque region. Like most young geologists, I began with the fossils and collected largely from the Jurassic formations of Skye and the adjacent islands, though the interesting problems presented by the general structure of the area, and more particularly by the igneous rocks, could not wholly escape the attention of an enthusiastic beginner. The results of these youthful labours were eventually communicated to this Society in the year 1857.

Having been appointed to the Geological training in methods of detailed geological mapping, and it so happened that this training lay, in large measure, among the ancient volcanic rocks so copiously developed among the Old Red Sandstone and Carboniferous formations of Central Scotland. I was thus led from the very outset to take a keen interest in volcanic geology, and the experience gained among the records of Palæozoic eruptions induced me to return to the study of the latest series of volcanic outbursts in Britain-those of the Western Isles. From time to time I communicated to the Royal Society of Edinburgh accounts of my investagations. At last, in the year 1871, I had advanced far enough to be able to
On some cases of the Conversion of Compact ‘Greenstones’ into Schists
Authors: Bonney T. G.
Published: October 2009

Last year I described some modifications due apparently to pressure in certain basic dykes. I am now able to supplement that account by a few notes on the changes produced by the same agency on a somewhat similar rock which, however, in all probability, was at first in a still more compact condition than any of those ‘greenstones.’

In the year 1880 I noticed, near the path leading from the Bernina hOspice to the Gü Alp (Engadine), a rather small mass of a green schist, so compact as to resemble a slate, associated with a fairly coarse gneiss. Their relations seemed explicable on the hypothesis of either an interstratificationof materials or an intrusion of the green rack into the gneiss. Each supoosition had its difficulties, and my impression was recorded in the following words:-“I can hardly believe the green rock to be anything but a schist” (meaning, according to my knowledge at that date, a rock originally sedimentary). I took away specimens and examined these afterwards with the microscope. The green rock presented the ordinary structure of a fine-grained schist; the gneiss gave some indications of a fragmental condition. But as I supposed (as I had been taught) that gneiss also was a metamorphosed sediment, this was not surprising; still it seemed strange that a rock, so little altered as the schist appeared to be, should be associated with one seemingly so much altered as the gneiss. Accordingly I deemed it best to keep the specimens in my cabinet, and
Notes on some Trachytes, Metamorphosed Tuffs, and other Rocks of Igneous Origin on the Western Flank of Dartmoor
Authors: McMahon C. A.
Published: October 2009

During the last two seasons I have spent some time in the examination of the rocks of igneous origin which occur between Lydlord and Okehampton, and which are beyond the area dealt with by Mr. Frank Rutley, F.G.S., in his memoir on the ‘Eruptive Rocks of Brent Tor and its Neighbourhood.’ As these rocks do not appear to havebeen described, some details regarding them may be of interest.

On the Geological Survey map a long outerop of ‘greenstone’ is depicted running from Great Cranaford, to the east of Sourton, almost as far as the West Okement River. The present paper is principally concerned with the outcrops of this ‘greenstone’ on Sourton Tors, South Down, and Meldon, and it will be found that they embrace a considerable variety of rocks.

I. Sourton Tors.

Sourton Tors form a ridge to the south-east of the village of Sourton (see the accompanying sketch-map). It rises to the heigh of 1447 feet above the sea, and 650 feet above the village. The rocks along this ridge crop out in the distinct lines; one of these—that on the western side of the ridge—forming a series of disconnected outcrops which I have numbered 3, 4, 5, 10, 11, and 12; and a second or easter line, which I have marked 2, 6, 7, and 8 on the accompanying map. The space between these two lines is covered with grass, and the rocks between them consist, it is to be presumed, of sedimentary rocks of the Carboniferous (Culm)
Note on the Occurrence of Perlitic Cracks in Quartz
Authors: Watts W. W.
Published: October 2009

I. Introduction

Since the publication of Mr. Allport's classical paper on the devitrefied pitchstones of Shropshire, in which he drew some very cautions deductions from the presence of perlitic and other structures in rocks of felsitic character, it has been customary to regard perlitic cracks as an indication that the material in which they occur has once been in a glassy condition. In 1893 I came across a specimen (I 860), forming part of the old rock-collection of the Irish Geological Survey, which raised grave doubts as to the safety of this wide generalization. it was obtained from Sandy Braes, in Antrim, and was a specimen of the ‘pearlstone’ of Portlock. When cut it exhibited admirable perlitic structure, not only in the glassy matrix of the rock, but also in the abundant porphyritic quartz-crystals which it contained.

Later on I found specimens, collected by Mr. Rhodes, in the English Survey Collection (I 926, 927), which exhibited the sam characters, and one of them (I 927) was so well preserved as to allow a thin slide to be made from it. It is this slide from which the most satisfactory of the figures illustrating this paper have been taken.

The specimens were obtained from the quarries at Sandy Braes, 1½ mile N.ER. of Tardree Mountain, in the northern part of the great rhyolite mass which is shown on Sheet 28 of the Geological Survey map of Ireland. I have reason to believe that the description of the petrological characters and field
Landscape Marble
Authors: Thompson Beeby
Published: October 2009

I was led to a study of the structure and origin of the so-called Landscape Marble, or Cotham Stone, through reading an article in the Geological Magazine for 1892, p. 110, by Mr. H. B. Woodward, entitled, ‘Remarks on the formation of landscape Marbled.’ To that article I am much indebted for information as to the general characteristics of the stone, and its mode of occurrence.

The first published description of the Landscape Marble occurs in a work by Edward Owen, the title of which is ‘Observations on the Earths, Rocks, Stones and Minerals, for some miles about Bristol, and on the Nature of the Hot Well and the Virtues of its Water’; the date on the title-page being 1754. The name ‘Cotham Stone’ was applied to the Landscape Marble because it was quarried, with other material, near Cotham House, on the northern side of Bristol, but Owen did not give it this name; he merely adopted the appellation by which it was already known in that part of the country (
op. cit.
p. 164).

At the time of Owen the Cotham Stone was chiefly known by and valued for its peculiar, corrugated, upper surface, ‘rustick’ so-called, though some cut and polished specimens were to be found framed in the houses of ‘the gentlemen of the neighbourhood.’

For convenience of reference, I shall number the descriptive paragraphs throughout this paper.

I. General Description of the Landscape Marble.

on the surface are often curiously interlaced, giving rise to the so-called ‘rustic-work’
Note on the Genus Naiadites, as occurring in the Coal Formation of Nova Scotia
Authors: Dawson J. William
Published: October 2009

In the autumn of 1892 Dr. Wheelton Hind was so kind as to invite me to place in his hands, for study and comparison, specimens of the bivalve shells from the Coal Formation of Nova Scotia, which I had described under the above generic name, and some of which were described by the late Mr. Salter in the Quarterly Journal of this Society, vol. xix. (1863), under his new generic names
Anthracoptera
and
Anthracomya
. Owing to illness I was unable, at the time, to comply with Dr. Hind's request, and thus the Nova Scotian species lost the benefit of a detailed comparison with the British forms in Dr. Hind's excellent paper of May 1893. I have now sent a collection of specimens to him, and beg to make the following remarks thereon.

These shells occur plentifully in some of the argillaceous shales of the Coal Formation, and occasionally on the surfaces of flaggy sandstones, but the most abundant repositories are the beds which I have named ‘calcareo-bituminous shales’ and ‘bituminous limestones,’ beds which, on account of their superior toughness and black colour, often stand out prominently in the coast-sections, and are sometimes almost entirely composed of these shells. As none of the properly marine species of the Carboniferous Limestone ever occur in these beds, and as they are closely associated with the coal-seams, I have always been greatly interested in them—in connexion with the various theories of the deposition of coal. I referred to them in this relation in ‘Acadian Geology,’
Further Notes on some Sections on the New Railway from Romford to Upminster, and on the Relations of the Thames Valley Beds to the Boulder Clay
Authors: Holmes T. V.
Published: October 2009

On March 9th, 1892, I had the honour of reading a short paper before the Society on the sections seen along the course of this new railway, dwelling chiefly on the cutting north of Hornchurch, in which a considerable mass of Boulder Clay had appeared, having a maximum thickness of 15 feet, and a horizontal extension of about 300 yards. The Boulder Clay lay in a slight hollow on the surface of the London Clay, and was covered by gravel belonging to the highest terrace of the Thames Valley system in the district, the surface of which varies from 90 to 120 feet above Ordnance datum.

At that time, and during many months afterwards, but little work was done in the cuttings nearer Romford than that just mentioned. The cutting at Butts Green and the more northerly excavation between Great Gardens and the junction with the Great Eastern Main Line at Romford remained in an almost stationary state. During the period between the spring of 1892 and that of 1893 I visited these cuttings many times, though without detecting anything but London Clay and gravel: more London Clay being visible at Butts Green than nearer Romford. However, last year the Romford cutting was considerably widened and deepened, and afforded sections of much greater interest than I had anticipated.
On the Stratigraphy and Physiography of the Libyan Desert of Egypt
Authors: Lyons H. G.
Published: October 2009

I. G
eneral
D
escription

The work of Geheimrath Karl A. von Zittel, as a member of the Rohlfs Expedition of 1874, has furnished us with an accurate geological description of the western oases of Egypt, which we can use as a starting-point for the further exploration of the Libyan Desert to the north and south of them, and his detailed sections and lists of fossils are of invaluable assistance in correlating the strata met with in various parts of this area

Still, I cannot find that much has been done since Dr. Zittel's work except by Dr. Schweinfurth, Sir J. W. Dawson, Prof. Hull, Prof. Walther, Prof. Mayrer-Eymar, and Mr. E. A. Floyer in the Fayum, the Nile Valley, and various parts of the eastern desert, while the western desert seems to have remained almost unexplored

In December 1893 and January 1894, when on a patrol visiting the oases of Kharga and Dakhla, and the desert routes to the south of them, I had opportunities of making a few observations in this portion of the desert which are, I venture to think, of some interest

These I have more recently (April 1894) been able to amplify by a ride through the more nothern part of this western desert, the easternmost monastery in the Wadi Natrum or the Valley of the Natron Lakes; thence along the valley some 20 miles to Dêr Baramus, the westernmost of the four Coptic monasteries. From this point I turned S.S.W. and went as directly as possible
The Occurrence of Dolomite in South Africa
Authors: Draper David
Published: October 2009

Mr. W. H. Penning, F.G.S., examined a certain rock near Lydenburg, when in company with Mr. A. C. Crutwell, and they described it in the Quart. Journ. Geol. Soc. vol. xli. (1885) p. 576, as “a peculiar blue, fine-grained, calcareo-siliceous rock.” This they named “‘chalcedolite,’ in consequence of the chalcedonic texture frequently displayed-indeed, some portions of the rock are true chalcedony.. . Sometimes it occurs in amorphous masses, weathered to a grey colour, and to a peculiar, rough, trachyte-like surface; but mostly in thin beds, 2 or 3 inches in thickness, with earthy partings.”

Mr Penning in another contribution, Quart. Journ. Geol. Soc. vol. xlvii (1891) p. 456, mentions the same rock (chalcedolite) as immediately overlying the ‘Black Reef series’ of what he calls the Megaliesberg Beds.’

Mr. C. J. Alford, F.G.S., in his ‘Geological Features of the Transvaal,’, mentions the occurrence and peculiarities of this rock as follows:-

Page 3. Referring to ‘alluvial deposits,’ he states:“In several places deposits of a fairly pure crystallite
carbonate of lime
are met with, those in the vicinity of the Six-mile Spruit, between Pretoria and Johannesburg, being some of the most remarkable; these appear to result from the disintegration of a hard blue quartzite plentifully veined

Page 6. “The metamorphism of these beds[‘schistose rocks’], where in contact with, or ajdacent to, the irruptive rocks, results in several somewhat complicated products; amongst others the calcareous quartzite before mentioned, which in some places passes into dolomite, and on exposure to atmospheric influence yields up its
The Bargate Beds of Surrey and their Microscopic Contents
Authors: Chapman Frederick
Published: October 2009

That division of the Lower Greensand known as the Bargate Beds is of especial interest on account of the varied character of its organic and inorganic constituents, many of which are derived from older rocks.

In 1856 R. A. C. Godwin-Austen wrote in reference to these beds:

“Whatever may have been the original range of the Oolitic group over the area now covered by the Wealden and Cretaceous formations of the S.E. of England, there is evidence that it has been reduced by the abrading action of the Lower Greensand sea along its coastline. The shingle-beds of the Lower Greensand of Surrey and Kent contain, in addition to the materials already alluded to, a considerable number of extraneous fossils, such as the bones and teeth of Oolitic Saurians,
Ammonites Lamberti
and
A. crenatus
of the Oxford Clay, in great abundance, together with
Terebratula fimbria
and
Rhynchonella oolitica
.”

The correlation of these Bargate Beds, with others of Lower Greensand age in the area east of that where the first-mentioned occur, cannot be regarded as settled. The Bargate Beds have been placed by the Geological Survey at the top of the by the series, whilst Mr. C. J. A. Meÿer regards them as forming the basement beds of the uppermost or Folkestone series.

It is not my intention here to discuss at any length their stratigraphical relations; but a summary of the evidence gathered after some detailed work in the Guildford and Dorking districts may be of some use in correlating the
Supplementary Note on the Narborough District (Leicestershire)
Authors: Bonney T. G.
Published: October 2009

T
he
outcrops of crystalline rock in the Narborough district were described,in 1878, by the Rev. Edwin Hill and myself in the second of our papers on Charnwood Forest.Since that time the old quarries have been much enlarged and others have been opened. These, one hoped, might have disclosed some new facts, and increased experience might occasionally suggest a different interpretation of things already seen. Hence I became anxious to pay a parting visit to the district before it passed, so to say, into other hands, and spent two or three days there in the Easter holidas of ]893,
2
without, however, the advantage of my friend's companionship, for just at that time he was unable to leave home.

On our former visits we had not succeeded in finding either any dykes cutting the crystalline masses, or more than one junction between the latter and the sedimentary rocks of the Forest series. I had hoped that in the process of quarrying some of the one and more cases of the other might have been discovered. But I was disappointed in both respects, though additional information was obtained as to the junction already known in the neighbourhood of Enderby. Some of the pits also afforded rather interesting sections of Boulder Clay. There is, however, so little to record that the fact of our former papers having appeared in this Journal alone emboldens me to submit this supplementary note to the Society.

The quarries near the villages of Enderby, Croft, Huncote, Stony Stanton, and
The Tarns of Lakeland
Authors: Marr J. E.
Published: October 2009

I
ntroduction

W
hen
discussing the origin of lake-basins, and maintaining the possibility of some of our English lakes lying in basins formed by earth-movement, I have often been asked whether I should consider that the basins of mountain-tarns could have been formed in that way. The difficulty of their being so formed seemed very great, and, supposing that they were true rock-bound basins, the conclusion appeared unavoidable that they were eroded by the action of ice. Some time ago I saw reasons for believing that certain tarns of Westmorland, though apparently in rock-basins, were not really so, and accordingly I have devoted some time during this year to the examination of a number of the tarns of Cumberland, Westmorland, and the Furness district of Lancashire, and now offer my observations to the Society as a contribution to the study of the origin of lake-basins, without in any way attempting to open up the question as to the origin of our larger lakes.

A casual glance at many of these tarns shows that the stream which issues from them runs over solid rock close to the surface of the lake, and this appears to have been considered by some a satisfactory proof that the tam itself occurs in a true rock-basin. It is the object of this paper to show that such is not the case. All who have written upon the tarns of the district agree that there are some which are partially or wholly moraine-dammed at the exit (using
The Pleistocene Beds of the Maltese Islands
Authors: Cooke John H.
Published: October 2009

For the right understanding of the Pleistocene beds, a previous knowledge of the physiography of the islands and of the earlier sediments is necessary. A full description of the physiography and of the character of the sediments, so far as they are necessary for the understanding of the accumulations forming the subject of the paper, occupies its earlier portion. Especially noticeable is the absence of ordinary anticlinal and synclinal folding, and the predominance of monoclinal faults, which largely affect the character of the surface. These faults were formed prior to the deposition of the Pleistocene beds.

The plateaux of Malta, rising to a height of 600–800 feet above sea-level, occur south of the great east-and-west fault, which has a downthrow to the north. They have no Pleistocene deposits upon their summits.

Three classes of superficial deposits are described :—

I.

Valley-deposits, including (
a
) those found on the higher slopes of plains and plateaux, due to subaërial waste and rain-action, containing land-shells and mammalian bones; and (
b
) those situated at, the bottoms of valleys, consisting of stratified layers of waterworn sand, gravel, and large pebbles, occurring in such order as to show that the agents which produced them have greatly decreased in intensity.

II.

Agglomerates and breccias found along coast-lines and faultterraces, always at the foot of the fault-terraces, or along the lower slopes of the depressed areas : these accumulations are either submerged or lie at the water-line. Their materials are much waterworn, and
Geological Notes of a Journey in Madagascar
Authors: Baron Richard
Published: October 2009

In the course of the year 1891 it fell to my lot to undertake a long and interesting journey of about 1200 miles in the island of Madagascar, during which I was able to make a few geological notes that may not be unworthy of record. Leaving the capital, I proceeded in a north-easterly direction as far as Imerimandroso, in the province of Antsihanaka; then struck due east, reaching the sea at Fenoarivo, a town situate about lat. 17° 25′ S. From here I followed the eastern coast, mostly along the water's edge, as far as the Bay of Diego Suarez, in the extreme north of the island; and thence I travelled down the north-western coast as far as the River Mevarano, in lat. 14° 37′ S., finally proceeding by boat to the island of Nosibe (long. 48° 15′ E., lat. 13° 20′ S.), visiting several of the smaller islands on the way. It is, of course, impossible to give a detailed account of the geological features of the country traversed during such a journey; but, as so little is known of the geology of Madagascar, a general sketch may not be without value. I may say that specimens of all the different rock-types met with on the route were collected,

For the sake of convenience, the part of the island travelled over may be divided into four sections : (1) that between the capital and the east coast, (2) the east coast (that is, the northern half of it),