bluuebunny/crossref_metadata_2025_split huggingface dataset:
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
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’
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 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),
On the Physical Conditions of the Mediterranean Basin which have resulted in a Community of some Species of Freshwater Fishes in the Nile and the Jordan Waters
Authors: Hull E. 
Published: October 2009

The Author summarizes the evidence in favour of the existence of barriers in post-Miocene times, separating the Mediterranean area into a chain of basins. He brings forward arguments in support of his contention that the waters of the eastern (Levantine) basin became fresh during a period when the area of evaporation was smaller, and the supply of river-water greater, than at present. Into this freshwater lake the waters of the Nile would flow directly. He has elsewhere given reasons for believing that the Jordan Valley from Lake Huleh to Arabah was the bed of a lake over 200 miles long, and at least 1300 feet above the present level of the Dead Sea. He suggests that the waters of this lake escaped into the Levantine basin through the plain of Esdraelon. With such physical conditions existing, the fauna of the Levantine basin would have a means of spreading throughout the whole system of waterways connected with it.
In conclusion the Author adds some observations on the changes which occurred in the Mediterranean area subsequent to the post-Miocene epoch of earth-movement.