bluuebunny/crossref_metadata_2025 huggingface dataset:
A Process for the Mineral Analysis of Rocks
Authors: Sollas William Johnson
Published: October 2009

It seems now to have become generally recognized that a natural classification of igneous rocks must rest ultimately on a chemical basis. The petrographer has thus become confronted with the necessity of an indefinite multiplication of chemical analyses, and may well shrink from the vast expenditure of time and labour that this involves. For many rocks there is no escape from this unpleasing prospect, but in the case of others, that is, all holocrystalline kinds which are not too fine-grained, the question suggests itself whether a quantitative estimation of the mineral composition might not solve the problem with sufficient accuracy. Provided that the chemical composition of the mineral constituents does not vary capriciously, but is definitely related to their physical properties, such for instance as their specific gravity, there would seem to be no good reason why it should not; while, as I hope to show later by instances, there even appear to be grounds for concluding that the question can be more positively answered in the affirmative.

In attacking the problem, the first step is to devise a method for obtaining a quantitative estimation of the mineral composition of a rock; and I may therefore proceed at once to describe a process which has been found to yield remarkably accurate results.

A fragment of the rock required for analysis having been selected, it is reduced to powder, by the usual process of crushing in a steel mortar and sifting through copper wire-gauze. The meshes of the sieve should number
On the Matrix of the Suffolk Chalky Boulder-Clay
Authors: Hill Edwin
Published: October 2009

Much study has been bestowed, upon the boulders included in the Glacial Clays, their nature, origin, and distribution. The matrix in which they lie has received comparatively little attention. Yet the matrix, in many or most, forms by far the largest part. I have been endeavouring to study this matrix under the microscope, by washing it, shaking it up with water, and so separating the material which will settle quickly to the bottom from that which remains longer in suspension. The process has to be repeated until the water remains clear, else dust still suspended dries on the surfaces of the grains which had settled and masks them from examination. I have collected and dried this finer dust, but it cakes together: I have not obtained from it much information. The coarser material, that which subsides first, forming from 40 to 75 per cent. of the whole, dries to a sand or powder and lends itself readily to examination with the microscope. I have tried several methods, and have succeeded best by inspection under direct daylight of the powder strewn on a slide. Inspected in this manner, Glacial Clays from localities in East Anglia tell something of their sources. I have examined specimens from places along a belt of country in Suffolk extending from Lowestoft to Bury St. Edmunds, a distance of more than 50 miles; Lincolnshire material dredged up in deepening the ship-channel to Boston (kindly sent by Mr. W. H. Wheeler, C.E.); Cambridgeshire specimens from Ely Cemetery and
The Fossiliferous Silurian Beds and Associated Igneous Rocks of the Clogher Head District (Co. Kerry)
Authors: Gardiner Charles Irving , Reynolds Sidney Hugh
Published: October 2009

I. Introduction

The area dealt with in this paper is situated in County Kerry, at the westernmost extremity of the Dingle promontory. The exposures are met with over an area measuring about 4 miles from north to south by 3 miles from east to west; but, owing to the great amount of peat and alluvium, the exposures inland are somewhat scanty, and one depends mainly on the magnificent coast-section for geological information.

The area is one of great interest to a geologist, from the splendid development in it of acid volcanic rocks, associated with beds mainly of Wenlock age. Except at Tortworth in Glouoestershire, and probably in counties Mayo and Galway, it is in the Clogher-Head district alone in the British Isles that contemporaneous volcanic rocks of Silurian age are definitely known to occur. While, too, the Tortworth volcanics are basic or intermediate in character and are mainly, if not entirely, of Llandovery age, in the Clogher-Head area the volcanic rocks are acid in character, and range throughout the Wenlock and up into the lower part of the Ludlow Series.

Considering the number of interesting features shown, the area has been comparatively little described by geologists of recent years, but this is readily explicable owing to its remoteness and inaccessibility.

The earliest reference to the geology of the district with which we are acquainted is contained in a paper by Thomas Weaver,
1
entitled ‘On the Geological Relations of the South of Ireland’. In this paper, which was read before the
On some Gaps in the Lias
Authors: Walford Edwin A.
Published: October 2009

The calcareous beds of the Middle Lias attain a maximum thickness near Banbury in Oxfordshire. They form the highlands of the escarpment (the outcrop) on the North Oxfordshire border at their highest altitude, 720 feet above Ordnance-datum.

The several zones of the Middle Lias may be put broadly into three lithological divisions:—

1.

Zone of
Ammonites spinatus
, and Transition-Bed. (Calcareous.)

2.

Zone of
Ammonites margaritatus
. (Argillaceo-calcareous.)

3.

Zone of
Ammonites Jamesoni
or
ibex
and
Amm. capricornus
, (Argillaceous.)

The deposition of divisions 2 and 3 followed a long period of sedimentation, mainly of argillaceous type. They are, in fact, repetitions of the previously existing conditions of the Lower Lias, differing only in a gradual increase in the thickness of the argillaceous limestones towards the top of the zone of
Ammonites margaritatus
. Similar conditions prevailed over the whole of the English Liassic seas. Though the incoming of the zone of
Amm. spinatus
was with some argillaceous deposit, the true zonal type was reached in the calcareous bands at the base of the great Ironstone Series, wherein the true fauna of the zone rests. In the Midlands and in Yorkshire these limestone-beds are at the lowest part of the 30 feet of rock and clay of the
Amm.-spinatus
zone. Nodular and concretionary bands characterize them. The nodular limestones are represented in Somerset, Dorset, and Gloucestershire by marly limestones yielding also the molluscan fauna of that part of the zone.

The ferruginous limestones of
On a Deep Boring at Lyme Regis
Authors: Jukes-Browne Alfred John
Published: October 2009

I. Introduction

During 1901 a boring was made near Lyme Regis in search. of coal, and was carried to the depth of 1300 feet without reaching the base of the Upper Triassic marls.

The story of this endeavour to find coal at a place where no geologist would have recommended the attempt, is one which has often been repeated at different places. The undertaking was promoted by a ‘practical man’ who had experience of coal-mining in South Wales, and who had convinced himself that coal was likely to be found at no great depth near Lyme Regis. He obtained permission to bore, and induced a certain number of persons to form a syndicate, for the purpose of making a boring to ascertain the depth at which the expected Coal-Measures were to be found.

The results of the boring have a twofold interest: first, to all people in the South-west of England they should be a warning against the folly of expecting to find Coal-Measures at a depth of less than 2000 feet below any part of Western Dorset; secondly, they are of interest to geologists, for the information which is thus afforded as to the great thickness of the Keuper Marls in Devon and Dorset.

It was anticipated that coal would be reached at a depth of less than 600 feet, and when this limit was passed without success it was decided to continue the boring to 1200 feet. At this depth it would have been abandoned, had it not
The Wood's Point Dyke, Victoria (Australia)
Authors: Mennell Frederic Philip
Published: October 2009

This dyke is intrusive into a belt of Silurian (Upper Silurian) strata which strike in a direction somewhat west of north, and extend beyond Walhalla on the south. Wood's Point is about 75 miles east of Melbourne. It may be taken as typical of the intrusions associated with the Silurian rocks of the Victorian gold-fields. Brown, original, hornblende is the dominant constituent, but it is rarely idiomorphic; augite, three varieties of felspar, micro-pegmatite, and ilmenite are also present, in a microcrystalline or cryptocrystalline groundmass. The rock is called a hornblende-porphyrite. In certain varieties cordierite occurs, and is accounted for by derivation from the adjacent shales. The reefs in the Silurian and Ordovician rocks usually occur at or near the contact with intrusive rocks. At Wood's Point the reefs are nearly horizontal, traversing dykes and shales, the junction usually marking the occurrence of rich ore. The Author notes the ‘almost invariable association of gold in this class of deposit with rocks containing original hornblende.’
Note on a Preliminary Examination of the Ash that fell on Barbados after the Eruption at St. Vincent (West Indies)
Authors: Flett John Smith
Published: October 2009

Two samples of the material were sent by Dr. D. Morris, C.M.G., of the Imperial Agricultural Department for the West Indies, to Prof. Judd, who forwarded them to the Director of the Museum of Practical Geology. They consisted of a fine greyish-brown powder, not unlike ‘flour-emery,’ but somewhat coarser and distinctly gritty to the touch. This powder was passed through a set of sieves, and it was found that 69 per cent. passed a sieve of 90 meshes to the inch, and 95 per cent, passed one of 60 meshes. All passed 30 meshes to the inch.

The 4 ‘ash’ contains plagioclase-felspar, hypersthene, monoclinic brownish augite, apatite, and magnetite, with fragments of a brown glass. The separated powders were all of much the same colour.

Plagioclase-felspar is the most abundant constituent, mostly in broken fragments of very irregular shape. It belongs largely to labradorite, but appears to include more than one variety. Perfect crystals are not uncommon. Glass-enclosures are very numerous, and are frequently rectangular in outline: they often contain very small stationary bubbles.

Many of the felspars have a thicker or thinner skin of glass adhering to their surfaces. This glass is brown, somewhat turbid, isotropic, with often many small rounded steam-cavities. The perfect crystals of felspar are often lozenge-shaped, as they lie on the broad flat brachypinacoid, being bounded by 001 and 201.

Hypersthene is next in frequency. The larger crystals are strongly pleochroic in green and reddish-brown tints, as is usual in a volcanic hypersthene which is
The Crystalline Limestones of Ceylon
Authors: Coomáraswámy Ananda K.
Published: October 2009

I. Introduction.

In 1860 Baron Ferdinand von Richthofen recorded the occurrence of limestones in Ceylon. He observed the intimate associations of ‘gneiss’ and granular limestone, and the transitions between the two.

Mr. A. C. Dixon has given a short account of the beds of limestone as follows:—The ‘beds run through the gneiss in a somewhat parallel direction, striking generally north-west by north to north, and having various angles of dip, from 10° to 40°.’ He refers to five bands. ‘The first is one which outcrops a few miles this side of Balangoda, and runs north-north-west, occurring again at Hunuwala. The second runs through Dolosbage and Maskeliya; probably the bed occurring at Bilhul Oya is continuous with this. The third outcrops under the Great Western [Mountain] on the Great Western Estate, and is continuous to the north-north-west with the Wattegoda and Medakumbura dolomites, and probably also with the beds at Gampola and Kurunegala. .A subsidiary bed—or it may be an outlier of this—occurs near the Pussellawa rest-house. The fourth bed outcrops largely at Wilson's Bungalow, Glen Devon, Dumbara, and Matale. The fifth occurs in the Badulla District.’ (
Op. cit.
pp. 42–43.)

I may say that the identity of these bands over such considerable distances requires confirmation.

Under the name of cipolin , Prof. A. Lacroix has described some specimens of crystalline limestone from Ceylon, which form part of the De Bournon collection belonging to the Collège de France and that of Leschenault de la Tour in the Muséum d'Histoire Naturelle, Paris.
The Origin and Associations of the Jaspers of South-eastern Anglesey
Authors: Greenly Edward
Published: October 2009

I. Introduction.

One of the most singular and striking rocks in that region of Anglesey which lies to the south-east of the principal mass of Carboniferous rocks, is a bright red jasper. Though never in masses of large size, it is widely distributed, occurring in three distinct areas, which may be called the Newborough, the Pentraeth, and the Beaumaris areas. The character, mode of occurrence, and associations of this jasper throw much light on its origin; they are so remarkable, and present such singular analogies with those of groups of rocks which have lately been described in different parts of the world, as to be, I think, matter of general interest, as well as important to workers among the older rocks of Britain. The object, therefore, of this paper is to describe the rocks and their relations in the districts where they have escaped the effects of the movements that have modified most of the region.

Their geological age, and, in particular, their relations to the crystalline schists of the region, cannot, in my opinion, be regarded as settled, some of the evidence being conflicting. But as questions of the greatest interest regarding metamorphism are involved, I propose, in the fourth part of this paper, to set forth this evidence as briefly as is consistent with clearness. I am the less unwilling to do so, because the problem is so closely allied in its nature to those that are still under discussion at the margins of several other metamorphic areas
Revision of the Phyllocarida from the Chemung and Waverly Groups of Pennsylvania
Authors: Beecher Charles Emerson
Published: October 2009

It is now eighteen years since I prepared a memoir for the Second Geological Survey of Pennsylvania, describing the species of Phyllocarida then known from the Chemung (Upper Devonian) and Waverly (Lower Carboniferous) Groups in that State. Subsequent collecting at the original locality has yielded a quantity of material which further elucidates the characters of the original species, and also adds two distinctly new forms to the fauna of the Waverly Group.

The specimens described in the present paper, as well as those on which the original descriptions were based, were all obtained in the vicinity of Warren (Pennsylvania). The chief horizon is in the shale-beds of the Upper Chemung Group, about 50 feet above mean water-level in the Alleghany River. At this level, crustacean remains are fairly abundant, and constitute a conspicuous element of the contained fauna. On this account, the deposits have been called by me ‘the Phyllocarid-Beds.’ The species thus far secured from the horizon are
Echinocaris socialis, Tropidocaris bicarinata
, and
Elymocaris siliqua
. Other forms are much less abundant, and occur in a sporadic manner in the higher strata.

The following notes on the genera and species are to be considered, not as complete descriptions, but as additions and emendations to the original diagnoses.

The new material representing this species, consisting of more than a hundred individuals, presents a greater range in size than was originally observed, and permits of a more exact description of the postabdomen, the ornamentation of the somites, and the number of lobes
The Glaciation of Teesdale, Weardale, and the Tyne Valley, and their Tributary Valleys
Authors: Dwerryhouse Arthur Richard
Published: October 2009

My attention was first called to this District by reading the admirable paper by Mr. J. G. Goodchild on the distribution of the boulders of Shap Granite over the moors in the neighbourhood of the Vale of Eden
1
. In this paper, Mr. Goodchild describes the track taken by the ice which carried the boulders of Shap Granite across the Valley of the Eden, and traces these boulders past Brough-under- Stainmoor to the summit of the Pennine Escarpment, at the head of Lunedale, Balderdale, and Deepdale. Here Mr. Goodchild leaves us, but the rocks have been traced by Prof. Lebour and other observers, down the lower part of Teesdale and out into the North Sea, and also down the Central Valley of Yorkshire as far as the city of York.

In the present communication it is my intention to deal with the distribution of the ice in Upper Teesdale, We~irdale, and the Valley of the Tyne, and their tributary valleys, and to discuss certain features produced during the retreat of the ice.

Teesdale. (1) Topography and Structure.

In order that the details which follow may be better understood, I purpose first to describe briefly the form and the solid geology of the district.

The Tees rises on the eastern side of Cross :Fell, and receives several tributaries from the surrounding hills. The upper part of the valley has a low gradient, especially in the region immediately above the waterfall of Cauldron Snout. The upper end is enclosed by a semicircle of
The Mineralogical Constitution of the Finer Material of the Bunter Pebble-Bed in the West of England
Authors: Thomas Herbert Henry
Published: October 2009

I. Introduction.

Much work has already been done on the pebbles and larger fragments of rock of the Budleigh-Salterton Pebble-Bed, but little or none on the finer material forming the matrix of this most interesting deposit. It occurred to me that a microscopic investigation of this finer material might bring out a few points of geological as well as mineralogical interest. Therefore it has been my endeavour to make as complete a mineralogical analysis of the sands as possible.

Specimens were collected at intervals along the strike of the Pebble-Bed, from Budleigh Salterton on the southern coast of Devon to Fitzhead, north of Milverton, in Somerset; other sands, for comparison, were taken from the Red Rocks above and below.

After treatment with acids, so as to remove the coating of iron-oxides from the grains, the sands were separated by means of heavy liquids into three parts:—

(
a
)

Heavy residue, with a specific gravity greater than 2·80.

(
b
)

The bulk of the quartz; and

(
c
)

The lightest part, with most of the alkali-felspar.

II. Petrography of the Sands: Description and distribution of the Mineral Species.

At the southern end of the outcrop of the Pebble-Bed, the matrix consists of incoherent material, each sand-grain being covered with a coating of red iron-oxide. On tracing the deposit northward, however, to the borders of Somerset, the bed loses much of its red colour, and in this area, owing to the presence of many masses
A Descriptive Outline of the Plutonic Complex of Central Anglesey
Authors: Callaway Charles
Published: October 2009

I. Introduction.

Twenty-two years ago, a paper by me on ‘Some New Points in the pre-Cambrian Geology of Anglesey’ appeared in the Geological Magazine.‘ One section of that paper discussed the ’ Continuity of the Granitoid Series with an underlying Gneiss,‘ and the chief evidence for that continuity was furnished by the Craig-yr-Allor anticline. An ellipsoidal dome of hornblendic and chloritic gneiss in Central Anglesey was described as surrounded by ’granitoidite,‘ below which it appeared to dip in a quaquaversal manner. As both the gneiss and the granitoid rock were then generally regarded as of sedimentary origin, the inference that the gneiss represented a formation older than the ‘granitoidite’ appeared to be justified. We now know, however, that these rocks are not metamorphosed sediments, but plutonic masses; therefore they can never have been in stratigraphieal sequence. A review of the ground in the light of the new theory of origin has now been undertaken, and the following paper is the result. I include within its scope the acidic rocks, both massive and schistose, which are associated with the gneisses and granite, so as to present a general outline of the structure of the plutonic complex of Central Anglesey. I do not propose to enter into minute petrographical or geognostic details : the former being unnecessary for my purpose, while the latter would be superseded by the expected mapping of Mr. :Edward Greenly. Some corrections were made in the old interpretations of the district by the Rev. J.F. Blake “ in
Alpine Valleys in Relation to Glaciers
Authors: Bonney Thomas George
Published: October 2009

Evidently faith in the excavating power of glaciers will not become extinct in the lifetime of Prof. W. M. Davis, for he has recently credited them with the making of not only the Alpine lakes, but also no small part of the valleys. They have produced, in his opinion, similar effects in Central France also and in Norway. Into these countries, though I know both fairly well, I cannot follow him without making an undue demand on the Society's patience, so I shall restrict myself to the Alps, and in doing this shall say very little about the Ticino Valley, which in Prof. Davis's paper occupies a prominent position. That I pass over (although, as it happens, my own ideas on this subject assumed a more definite form during a stay in one of its ‘hanging valleys’ four years ago) because I found that my friend and successor, Prof. Garwood, had devoted some time last summer to testing Prof. Davis's hypotheses in the place of their nativity, and was no nearer being a convert than myself. So I have ceded that region to him, and select for my purpose one or two other districts with which I am not less familiar, and apparently more so than Prof. Davis, whose method of dealing with this intricate problem does not strike me as satisfactory: for, so far as I can discover, he did little more than travel through the Alps by one or two frequented routes.But a problem of this kind cannot
On the Origin of some Hanging Valleys in the Alps and Himalayas
Authors: Garwood E. J.
Published: October 2009

I. Introduction.

During my visit to the Eastern Himalayas in 1899, I was much struck by the discordance of certain of the tributary valleys to the main valleys which they feed in the district of Jongri, near the south-eastern foot of Kabru. While making a plane-table survey of this district, I arrived at certain conclusions with regard to the origin of these valleys, which I have already published in the journal of a kindred Society. I was, therefore, much interested when my attention was drawn to a paper by Prof. W. M. Davis on ‘Glacial Erosion in the Valley of the Ticino,‘ in which the hanging valleys in the lower part of the Val Ticino are attributed to the over-deepening of the main valley by ice. His theory of their origin may be briefly stated in the following paragraph taken from the paper above cited :—

‘The deepening of a glaciated valley for a good part of its length is thus seen to be a general result of glacial erosion; it is accompanied throughout by discordant or hanging lateral valleys, and the production of a lake in the distal portion of such a valley is but a subordinate result of glacial action.’ (Op. cir. p. 152.)

This theory of the origin of hanging valleys is diametrically opposed to the one at which I had arrived, from a study of similar valleys in the Sikhim Himalayas. Coming as it does, however, from one of our foremost exponents of drainage-problems, it
On the Jurassic Strata cut through by the South Wales Direct Line between Filton and Wootton Bassett
Authors: Reynolds Sidney Hugh , Vaughan Arthur
Published: October 2009

I. Introduction.

A paper like the following, dealing with a newly-exposed section, does not require any long introduction, and naturally the number of previous communications on the subject is limited. We know of only two, namely:—Mr. H. B. Woodward's account in the ‘Summary of Progress of the Geological Survey for 1898,‘ pp. 188-94, and the Rev. H. H. Winwood's Report on the Excursion of the Geologists’ Association to the new Great Western Railway-line from Wootton Bassett to Filton, Proc. Geol. Assoc. vol. xvii (1901) p. 144.

II. The Liassic Sections West of Sodbury Tunnel.

1. The Main Section.

(
a
) The White Lias.

Resting directly upon a thin bed of typical Cotham Marble is a compact, cream-coloured limestone, about 1 foot thick; this bed forms a marked horizon, not only by reason of its peculiar texture, but also on account of the levelness of its surface. It represents the ‘White Lias’ of the Somerset area and, in particular, the ‘Sun-Bed’ of the Radstock district.

(
b
) The
Ostrea
- and
Torus
-Beds.

Immediately above the Sun-Bed is a series of limestones and subordinate shales, forming a total thickness of about 5 feet. Although no specimen of
Psiloceras planorbis
was found, the horizon of these beds is well marked zonally by
Ammonites Johnstoni(=Amm. torus)
, which is not uncommon in the upper strata. The series is, however, chiefly characterized by
Ostrea liassica
and its numerous mutations which abound throughout, but especially towards the base.

The following is a complete list of the fossils that we
On a new Boring at Caythorpe (Lincolnshire)
Authors: Preston Henry
Published: October 2009

During the early part of the present year (1902) a boring was made near Caythorpe, for the purpose of obtaining a water-supply from the Marlstone. Rock-bed of the Middle Lias. The work was done for Mr. E. Lubbock, of Caythorpe Court, and the boring is about a third of a mile east of the house. A well has been dug to a depth of 46 feet, and from the bottom of this well a 6-inch boring was put down. The thickness of the Upper Lias in this district is usually taken to be about 110 feet, but the present boring has shown it to have here a thickness of feet. The section is as follows:—

The rest-level of the water in the borehole is at a depth of 175 feet from the surface, or 145 feet above Ordnance-datum.

The boring was made by Mr. J. E. Noble, of Thurlby, near Bourne, under my own superintendence, and samples of boring-débris were sent to me at frequent intervals. Previous to this boring being made, four other wells had been sunk, which passed through the limestone and into the Liassic clay. The positions of these wells are shown on the plan (fig. 1, p. 30).

The normal dip of the beds is south-easterly, and, as will be noticed, Wells Nos. 1, 3, & 5 lie approximately in the line of dip, and in continuation of the lower part of the road; and hence a section (fig. 2, p. 30)
On some Well-Sections in Suffolk
Authors: Whitaker William
Published: October 2009

Some 470 well-sections in Suffolk were noticed in thirteen Geological Survey Memoirs up to the year 1893. Many of these were shallow, but many were of considerable depth. Few of the accounts had been published before.

Two years later, seventeen fresh sections were described in a paper on some Suffolk well-sections, and since then four others have been noticed in various publications.

As notes of thirty-one more have accumulated; as there is no opening for the printing of these, either in a Survey Memoir or in the publication of a local society (for there is no such publication); and as some of them have points of considerable geological interest, it is hoped that I may be forgiven for bringing matters of local detail (such as the following sections of twenty borings) before the Geological Society, which, as a rule, is hardly the proper place for them.

Though ready to take a somewhat extended view of a remark made by a former President, that papers of local character would find a more appropriate birth near the place of their conception, yet I think it better that such papers (at all events my own) should be born rather than strangled in embryo.

The object of this paper is to show how greatly our knowledge may be added to by wells or borings, and how sometimes these give results that could not have been expected.

Woodbridge

If there is a place in Eastern Suffolk where one might reasonably expect to be able
The Cellular Magnesian Limestone of Durham
Authors: Abbott George
Published: October 2009

The Permian Limestone covers about 1¼ square miles near Sunderland; it alternates with beds of marl containing concretionary limestone-balls, and attains a thickness of 65 feet or so. The cellular limestones frequently contain more than 97 per cent. of calcium-carbonate. Magnesium-carbonate occupies the interspaces or ‘cells’ of this limestone, and also the spaces between the balls. The hundred or more patterns met with in it can be arranged into two chief classes, conveniently termed honeycomb and coralloid, each with two varieties; and each class has four distinct stages, both classes having begun with either parallel or divergent systems of rods. The second stage is the development of nodes at regular distances on neighbouring rods; and these in the third stage, by lateral growth, become bands, finally, in the fourth stage the interspaces become filled up. The upper beds are usually the most nearly solid. In the coralloid class the nodes and bands are smaller and more numerous than in the honeycomb class. In both classes tubes are frequently formed. The rods have generally grown downwards, but upward and lateral growth is common. A section of Fulwell Quarry is given.
Notes on the Geology of Patagonia
Authors: Scrivenor John Brooke
Published: October 2009

Apart from the papers dealing with the extinct vertebrate faunas, the following are important works on the geology of Patagonia. For further literature, see the bibliography appended to Dr. Ortmann‘s Report.

II. The Sedimentary Rocks.

The latest classification of the Patagonian sediments is that by Mr. J. B. Hatcher, who conducted the Princeton University Expeditions. Previous to its appearance, M. Alcide Mercerat, of Buenos Aires, published a classification based on his observations in Southern Patagonia. Both are summarized here in tabular form:—

During several manths' travelling in Patagonia I had opportunities of gaining some knowledge of the geology of the country; but, owing to the great distance traversed in the time, I found that it was impossible to study the stratigraphy satisfactorily, except in the neighbourhood of Santa Cruz, where a few weeks were spent. In that district the Patagonian and the Santa Cruz Beds are excellently exposed, as also is the ‘gravel-formation,’ which, in order to avoid any confusion, will be referred to hereafter as the Téhuelche Pebble-Bed.

Fig. 1 (p. 162) represents a section of the Patagonian Beds at Entrance Point, at the mouth of the Rio Santa Cruz. The divisions mentioned by Darwin in ‘Geological Observations’ lie respectively between the 272-foot and 220-foot levels, the 220-foot and 159-foot levels, the 159-foot level and the talus-marks. These beds were also examined 18 miles up stream, on the estancia of Don Pedro Richmond, where they yield a rich invertebrate fauna. The section here does not present so varied a
The Figure of the Earth
Authors: Sollas William Johnson
Published: October 2009

Some of the more striking features of our planet are apt to escape attention if our studies are made upon charts without the assistance of a ‘globe.’ Thus the remarkable alignment of many volcanoes, volcanic islands, coast-lines, and even mountain-chains along circular arcs does not seem to have excited the interest which might otherwise have been expected. An arc-like form is not infrequently alluded to, but the almost precise correspondence of some great terrestrial features with a circular form seems to be generally overlooked. As an example, the chain of the Aleutian Islands may be cited: it is certainly one of the most perfect. If a circle be swept out on a terrestrial globe with its centre in lat. 6° N., long. 177° W., its circumference passing through one of the islands of the festoon will traverse nearly all the rest and extend through the length of the Alaskan peninsula. (See Al in fig. 2, p. 183.) The correspondence is so precise as to suggest that it must have some real physical meaning. The numerous mighty volcanoes which characterize the region point to the existence of an extensive subterranean reservoir of lava, and to discontinuity of the earth's crust, in the form of a circular crack. It is difficult, as we look upon this part of the globe, to avoid the impression that we have before us the remains of a spherical dome or blister, which has broken down along circular and radial fractures, the islands standing over a circle, the coasts of the Kamchatkan
On a New Species of
Acrolepis
obtained by Mr. Molyneux from the Sengwe Coalfield
Authors: Woodward Arthur Smith
Published: October 2009

The large slab of ferruginous sandstone obtained by Mr. Molyneux from the Sengwe Coalfield exhibits the imperfect remains of five ganoid fishes, besides scattered fragments probably of others, all belonging to the same species. One specimen (Pl. XX, fig. 1) indicates the approximate length of the head, two others seem to show the maximum depth of the trunk, while another displays the greater part of the heterocercal tail (Pl. XX, fig. 2). All the specimens exhibit the scales, and there are also some traces of the paired and anal fins. It is thus possible to determine many of the characters of the genus and species represented.

The fish to which these remains belong is laterally compressed, and must have measured at least 60 centimetres in length, with a maximum depth of about 15 centimetres. The length of the head with opercular apparatus seems to have been approximately equal to the maximum depth of the trunk. The caudal pedicle is clearly very slender, and the upper caudal lobe is much elongated (Pl. XX, fig. 2).

The external head-bones are ornamented with thick rounded rugæ, but they are crushed together beyond recognition. The direction of the mandibular suspensorium is very oblique.

The enamelled scales are thick, rhombic in shape, and regularly arranged over the whole of the trunk. They are very deeply overlapping; and those of the flank are united by a peg-and-socket articulation, without any strengthening ridge on the inner face (P1. XX, fig. 4). The principal scales of the flank
Notes on some Fossil Plants collected by Mr. Molyneux in Rhodesia
Authors: Arber E. A. Newell
Published: October 2009

The fossil plants from Rhodesia collected by Mr. Molyneux, and presented by him to the British Museum (Nat. Hist.), are, so far as I am aware, the first specimens to be described from this region. They were obtained from three different localities. The most noteworthy are those from a small area of fine horizontal sedimentary beds, resting on nearly vertical metamorphic rocks, at the Sisi siding on the Bechuanaland Railway. Two of the specimens [V 7592–93] from this locality contain fairly well-preserved fronds of the fern-like plant
Glossopteris Browniana
, Brongt., and of some of its varieties.

Some of these fronds are remarkable, as showing what I think may possibly prove to be the imprints of the son or the sporangia. Our present knowledge of the reproductive organs of
Glossopteris
is very unsatisfactory. Nothing whatever is known as to the structural features of the sporangium. The position of the sori or of the sporangia on the frond is still doubtful, for the markings exhibited by certain fronds of this plant, which were regarded by Bunbury and Feistmantel, and more recently by Prof. Zeiller, as indicating the position of the sort, may have had no real connection with the fructification. The markings consist of fairly-large, circular, or oval spots or holes, usually lying in two or more longitudinal series on either side of the midrib. As has been pointed out by several authors, these certainly suggest that the position of the sort may have been similar to that of certain recent Polypodiaceous
On a New Species of
Solenopsis
[
Solenomorpha
] from the Pendleside Series of Hodder Place, Stonyhurst (Lancashire)
Authors: Hind Wheelton
Published: October 2009

Solenomorpha Major
, sp. nov.

(Fig. 1, p. 335.)

Specific charaeters. — Shell above the medium size, transversely elongate, ovato-lanceolate-truncate, very inequilateral, broad and convex in front, narrowed and compressed posteriorly, only slightly convex from before backward, more so from above downward. The anterior border is rounded, the inferior border prolonged and elliptieally curved, the posterior short, bluntly obliquely truncate. The hinge-line is curved in front, long, and almost straight posteriorly. The umbones are obtuse, and placed in the anterior fifth of the valve. There seems to have been an elongate, narrow escutcheon.

Interior.—The anterior adductor-scar is large and rounded. Other characters and the hinge unknown.

Exterior.—The shell is ornamented with fine, close, concentric lines of growth, which follow the contour of the valve.

Dimensions.—Antero-posteriorly = 136 millimetres; dorsoventrally = 42 ram.; gibbosity of valve = 5 mm.

Horizon and Locality.—Shales of the Pendleside Series, River Hodder, Hodder Place, Stonyhurst (Lancashire).

Observations.—This beautiful specimen was found by the Rev. Charles Hilldreth, S.J., who has most kindly presented it to the Museum of Practical Geology, Jermyn Street. The specimen is that of a perfect left valve, evidently a full-grown example, somewhat crushed along the hinge-line. The gradually-tapering posterior end and general shape point to the genus
Solenomorpha
, to which I now refer it without hesitation.
S. major
is so much larger, more compressed, and deeper than
S. minor
, that there is no danger of the two species being confused.

I have described and figured two species of
Solenomorpha
in my Monograph of
The Lowest Beds of the Lower Lias at Sedbury Cliff
Authors: Vaughan Arthur
Published: October 2009

The two chief points of interest in the Lower Lias of Sedbury Cliff, which I examined in company with Mr. L. Richardson, are, firstly, the relation of the basal conglomerate to the Cotham Marble and White Lias of neighbouring districts; and, secondly, the examination of the faunal sequence, with a view to testing the absolute value of ammonite-zones.

1. The Conglomerate.

This is composed of fragments of a very compact, lithographic, argillaceous limestone, which exhibits well-marked conchoidal fracture. The large fragments are invariably tabular and lie horizontally, their vertical dimension being small compared with their horizontal extent; all of them show internal, horizontal bands of colour which may undoubtedly be considered to have existed in the original rock-layer from which the fragments were broken. The smaller fragments lie in all directions, and many of them are rounded; they almost invariably exhibit an outer, more deeply stained shell, the colour of which shades off inward quite uniformly and imperceptibly. There can be little doubt that this staining has been produced subsequently to the breaking and rolling of the fragments, and, most probably, subsequently to their cementation into a conglomerate.

That the fragments of the conglomerate once formed part of a layer exactly similar to the true Cotham Marble of the Bristol and Sodbury areas, is almost without question, since they agree absolutely in lithological characters with specimens of that rock, though I have noticed no fragments which show the peculiar arborescent markings. It is, however, important to notice that the arborescent
The Geology of the Tintagel and Davidstow District (Northern Cornwall)
Authors: Parkinson John
Published: October 2009

Introduction.

Since the publication in 1839 of the far-famed Memoir by Sir Henry de la Beche on the ‘Geology of Cornwall, Devon & West Somerset,’ a large part of the first-named county has been left comparatively unmolested, alike by the hammer and by the theories of the geologist. Thus the district which lies to the west-ward of the fossiliferous Upper Devonian Beds of South Petherwin and Landlake, from St. Clether, in a westerly direction,
via
Davidstow and the North Cornwall branch of the London & South-Western Railway to the coast, has been almost untouched, except for four papers, since the date above mentioned.

My sincere thanks are due to Prof. T. G. Bonney, F.R.S., for kind suggestions in the course of the preparation of this paper; to Lieut.-Gen. C. A. MacMahon, F.R.S., for the loan of slides of the Cock's Tor rock; to Miss Raisin, D.Sc., for specimens and slides from the Ardennes; to Mr. G. T. Prior and Dr. J. S. Flett, for invaluable aid in determining some of the minerals; and to Mr. E. T. Newton, F.R.S., for kind help with the fossils. These are, from the coast east of Tintagel Head (between Barras Gug and Smiths Cliff) forms comparable with
Atrypa flabellata
and with
Posidonomya
; and
Spirifera Verneuilii
from Lanterdan Quarry.

A list of fossils from Tintagel was given by Holl.

In regard to the general structure of the country, two points are of great importance. First, ly, from St. Clether on the east to the Rocky
The Toarcian of Bredon Hill, and a Comparison with Deposits elsewhere
Authors: Buckman S. S.
Published: October 2009

I. Geology.

The Upper Lias (G 3) of Bredon Hill is shown on the Geological-Survey map as more than 300 feet in thickness. It is said to be as much as 380 feet thick, whereas at Wotton-under-Edge, some 36 miles to the south, it is said to be only 10 feet. But at the former locality the Inferior Oolite (G 5) is represented as resting directly on the Upper Lias (G 3); at the latter locality there is shown, between Inferior Oolite and Upper Lias, a development of some 150 feet of strata called ‘Midford Sand’ (G 4)—the Cotteswold Sands overlain by the Cephalopod-Bed. The question often presented itself to my mind—Were the two so-called ‘series’ of Upper Lias the same, or was not the Upper Lias of Bredon Hill really much more than the Upper Lias of Wotton, so that there was not a true comparison? Was it not an argillaceous condition of the sands and the overlying Cephalopod-Bed?

Some few years ago I was able to answer this question partly in the affirmative. On the north slope of Bredon Hill, I found in some argillaceous stones in a gateway, many feet below the yellow limestone of the Inferior Oolite, portions of ammonites indicative of beds contemporaneous with the Cephalopod-Bed of the Cotteswolds: they indicated strata of the hemeræ
Moorei, dispansi
, and
Struckmanni
.

When the Cotteswold Naturalists' Field-Club visited Overbury on the south side of Bredon Hill, in 1902, the members found in the gravel-pit many ammonites confirming my
On a New Cave on the Eastern Side of Gibraltar
Authors: Acland Henry Dyke
Published: October 2009

A new cave was discovered on the eastern side of Gibraltar on August 15th, 1902. It is situated a short distance south of the eastern end of the tunnel which pierces the Rock, from the Dockyard on the western side to ‘Monkey's Quarry’ on the eastern. Blasting and quarrying operations are being carried on in the quarry, to procure material for the new dockyard. An explosion is said to have blown in the thce of the limestone-cliff, and a small hole was discovered; when this was entered, it was found that it led into a cave of considerable dimensions. I have not been able to determine whether the hole was made in the ‘massif,’ or whether the explosion merely blew away the rubble and breccia that forms the talus of the cliff, thereby uncovering an old entrance. Further quarrying operations have so enlarged the opening that none of the original cliff-face remains very near it. I am told by Mr. A. K. Peaty, Assistant Civil Engineer, that he saw the opening two hours after it had been made, and that, in his opinion, the hole had been pierced through the massif, and was not a reopening of the old entrance. In any case, it must have been very near an old entrance, as a glance at P1. VI, fig. 1 shows that the stalagmite-floor slopes up to within a few feet of the present opening, and the sides of the cave, so far as they can be seen through the
Notes on Upper Jurassic Ammonites, with special reference to Specimens in the University Museum, Oxford: No. I
Authors: Healey Maud
Published: October 2009

In the course of rearranging the Upper Jurassic fossils in the University Museum, Oxford, my attention has been called to the large amount of misconception which exists with regard to Sowerby's species
Ammonites plicatilis
and
Am. biplex
. The former is rightly recognized in England as the zone-fossil of the Upper Corallian, but Dr. J. von Siemiradzki gives the name to a specimen from the
ornatus
-zone. He makes the following surprising remark with reference to it:—

‘Da Sowerby's Originale nicht erhalten sind, bleibt uns nichts anderes übrig, als die nächst älteste Figur von Phillips als Typus der Art anzusehen.’

The original specimen is in the Buckland Collection in the University Museum, Oxford; but even if it had been lost, Sowerby's figure would have had a better right to be taken as the type than that of Phillips, for it has the priority and there is no ambiguity about it, while the history of the latter is very involved and the original, so far as I can ascertain, is not preserved. The reference which Dr. Siemiradzki gives for it is ‘Geology of Yorkshire’ (1829) pl. iv, fig. 29, that is, the first edition, in which the figure in question is that of a keeled ammonite and is named
Ammonites solaris
; while the figure which he gives as an example of
Perisphinctes plicatilis
makes it quite clear that he is really referring to the third edition (1874), in which fig. 29 on pl. iv is that of a species of
Perisphinctes
and is
The Age of the principal Lake-Basins between the Jura and the Alps
Authors: Du Riche Preller C. S.
Published: October 2009

1. In a paper read before the Societ'y. in 1902, the Author showed, on the evidence of extensive high-level deposits of Decken-schotter in Subalpine France and Switzerland, that the principal Swiss lake-basins could not have existed at the time when those deposibs were formed, during and after the first or Pliocene glaciation of the Alps. In the present paper he deals with the question reserved in the preceding one, that is, to which subsequent period the formation of those lake-basins should be assigned. By the light of further recent investigations in the different localities, he first considers the conditions of the Zurich lake-valley, where the successive glacial and fiuviatile deposits are clearly defined, and theu applies his conclusions to the other principal lake-basins lying in the same zone along the edge of the Alps.

2. The hitherto generally-accepted view that the lake-basins are pre-Glacial in the old sense, or were formed during the first inter- Glacial period, rests, in the main, on two arguments : (1) that the alluvia at the lower ends of the lakes are all Glacial, not only from their appearance, but because the materials composing them could only have been transported thence by glaciers, which either passed over the lakes by bridging them, or through them by completely filling them with ice; and (2) that the zonal bending of the Molasse along the edge of the Alps, to which the lake-basins owe their existence, odcurred before the second or maximum glaciation,because on the hills flanking the