bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Skull and Dentition of a Triassic Mammal (
Tritylodon longævus
, Owen) from South Africa
Authors: Owen Richard
Published: October 2009

A
collection
of fossils from the Trias of Thaba-chou, Basuto-land, submitted to me by Dr. Exton of Bloemfontein, Cape of Good Hope, included the subject of the present paper. It was associated with remains of some of the Reptilian genera (
Kisticephalus, Batrachosaurus
, e. g.) described in my ‘Catalogue of the Fossil Reptilia of South Africa in the British Museum’.

It is a skull with mammalian characters, lacking the hinder cranial end and the mandible, but retaining with the upper jaw its dentition, though many of the teeth are more or less mutilated. This dentition consists of incisors and molars, with a diastema of the relative extent shown in many Rodents and some Marsupials. The subjoined figures (Pl. VI. figs. 1–4), being of the natural size, dispense with notes of admeasurements.

The matrix adhering to this fossil is identical in colour, density, and composition, with that attached to the Labyrinthodont and other Reptilian remains therewith associated: the degree of petrifaction and the specific gravity of the mammalian fossil are the same. No Tertiary deposits or any recent petrifying formation, inducing such mineral change in bone and contiguous bed, exist in the locality whence this skull and the associated organic remains were obtained.

In the preserved portion of the cranium (Pl. VI. figs. 1,2,3) sutural tracts are recognizable: these determine the pair of parietal bones by the portions of them, 7, 7, which contribute to the calvarium; they meet above the upper mid line, and there develope a crest which has undergone
On the Cranial and Vertebral Characters of the
Crocodilian
Genus
Plesiosuchus
, Owen
Authors: Owen Richard
Published: October 2009

I
n
the ‘Preliminary Remarks’ to the palæontology of the Crocodilian Reptiles, Cuvier urges the need of a precise determination of the generic characters, with regard to which he writes, “observations, however novel, lose all their merit, unless they rest on this basis”.

He proceeds to exemplify the apophthegm by descriptions which have never been surpassed of new and interesting species of extinct Reptiles, especially Crocodilian, which he shows to have been erroneously referred to other previously defined genera.

Cuvier refrained from attaching generic names, distinct from those of his “subgenera” of existing Crocodiles, to the extinct forms of which his keen and careful observations had detected characters since generally admitted to merit such distinction, and of which a contemporary availed himself.

The characters which Cuvier defines as forming for the Crocodiles a “very natural genus” are now recognized as defining an ordinal group of the class Reptilia. But of this group he admits and names “Subgenera,” and to their distinctive characters he devotes special “Sections,” as, for example, “I°, Espèces de Caymans” (p. 30); “II°, Espèces de Crocodiles” (p. 42); “III°, Espèces de Gavials” (p. 59). Our Catalogues accordingly admit these groups of
Crocodilia
, under the generic names
Alligator, Crocodilus, Gavialis
.

In the
Section
III, “Sur les
Ossemens Fossiles
de Crocodiles,” the vertebral, dental, and narial characters of the extinct species are defined, and those of the “Secondary” or “Mesozoic” formations are of higher value than he assigns to his recent “Subgenera;” but he forbears to invent special terms for
On Streptelasma Rœmeri, a New Coral from the Wenlock Shale
Authors: Duncan P. Martin
Published: October 2009

V
ery
numerous specimens of simple Corals belonging to the Rugosa were found in the washed Wenlock Shale prepared by G. Maw, Esq., F.G.S. Amongst them are forms which have not hitherto been described, but which are allied to a species from Girvan. They belong to the genus
Streptelasma
, Hall, and are specifically distinct from any others. As the variability of some parts of these Corals is great, and there are some interesting points about their morphology, I have brought them before the Society in this communication.

The corallum is simple, free, reversely conical in shape, slightly bent and horn-like, sharp at the base, longer than broad, and with a circular or elliptical calicular margin.

The calice is widely open, shallow, and has a central depression leading to a more or less distinct fossula. About fifty costæ cover the corallum, and they are subequal in breadth, slightly rounded, and separated by linear depressions. Their length differs according to their position and direction, and there are four sets of them: three on the convex side of the bent corallum and partly on the flanks, and one on the concave side and partly on the flanks (figs. 4, 5, 6).

Of the three sets on the convex side, one is composed of two costæ placed side by side, and reaching from the base to the calice in a vertical line. They are usually slightly larger than the other costæ, and are very distinct and parallel (fig. 5). There is another set on either
On
Cyathophyllum Fletcheri
, Ed. & H., sp., from the Wenlock Shale, with Remarks on the group to which it belongs
Authors: Duncan P. Martin
Published: October 2009

T
his
coral occurs in the Wenlock shale, and the specimens are small and not numerous; those which are now under consideration come from Mr. G. Maw’s shale-workings.

The forms are young, and have a deep calice with septa barely projecting; there is a very perfect epitheca, and there are traces of costæ beneath it and of crossbar-like structures between them. There are no synapticulæ between the septa, and a tabula closes in the calice below.

The species is one of those which were associated by MM. Milne-Edwards and Jules Haime with the Fungidæ, under the genus
Palæocyclus
, in 1851. They remained thus included until 1867.

In the ‘Philosophical Transactions’ of the Royal Society, 1867, p. 651, pl. xxxii. figs. 6
a
–6
e
, a criticism of the genus
Palæocyclus
was published by me, and it was demonstrated from specimens and sections that the species included in it by MM. Milne-Edwards and Jules Haime could not be associated with the Fungidæ.

The necessity for examining into the minute structure of the
Palæocycli
came from the discovery of a Tertiary coral in Australia, which, from its shape, its possessing synapticulæ, and the absence of endothecal dissepiments was clearly a Fungid and a
Palæocyclus
. To believe in the descent without modification of a coral from the Silurian to the Australian Cainozoic was improbable, and sections were therefore made of a series of
Palæocycli
.It was stated in the essay (p.651), that “the absence of synapticulæ was proved,as was also the presence of an inclined dissepimental endotheca at
On some Tracks of Terrestrial and Freshwater Animals
Authors: Hughes T. M’Kenny
Published: October 2009

T
he
ancient rock-markings known as “Bilobites,” and afterwards described by D’Orbigny under the name of
Cruziana
, have long been known, and have proved a fertile source of controversy, some regarding them as plant-remains, and others looking upon them as traces of animals. A host of smaller, but similar markings, such as
Rysophycus
or simpler forms, as
Palæochorda
, or the various very constant and symmetrical varieties known as
Nereites
and
Myrianites
, or those with a more plant-like outline, as
Chondrites
, all belong to the same line of inquiry. Few writers on the Cambrian and Silurian rocks have not had to refer to what they called fucoidal markings, or worm-tracks, which often have their importance increased by being the only traces of life in the bed. Throughout the geological series to the present day, similar things are found.

But though observations on the tracks made by recent animals had long ago been made by Emmons (American Geology, Pt. vi. 1857), and though Dawson had watched and recorded the various markings produced between tides on the long shores of the Bay of Fundy (Acadian Geology, p. 25), it has remained for Nathorst, in his splendid monograph on “Tracks of Invertebrate Animals” (K. Svenska Vet. Academiens Handlingar, Band xviii. No. 7), to place the whole question on a new footing by his experiments with living marine animals, and his extended observations on recent and fossil forms.

The very full bibliography given by him renders it unnecessary to refer more particularly to the various authors
On some Rock-specimens collected by Dr. Hicks in Anglesey and N.W. Caernarvonshire
Authors: Bonney T. G.
Published: October 2009

T
his
series of specimens, which has been entrusted to me by Dr. Hicks for description, appears to me of the very first importance as throwing light upon the relations of the earlier rocks of North Wales. By his fortunate discovery he has welded, if the phrase be permitted, the last link in the chain of evidence which demonstrates the existence of Archæan rocks in that region. I propose, then, in addition to giving a description of the microscopic structure of the slides which he has had prepared, to offer a few remarks as to the significance of these structures and their bearing on the general question. But as some of the slides closely resemble specimens which have already been described at length by Mr. T. Davies and myself, I shall not feel it necessary in every case to enter into very minute details, unless they appear to me of some special importance.

(1)
Railway-cutting east of Llanfaelog
.—The rock-specimen is a very characteristic representative of the pale-coloured granitoidite from this neighbourhood. Its peculiar subcompact aspect distinguishes it readily from a normal granite, the quartz and the felspar appearing to the eye as if imperfectly separated one from the other. Parts of the specimen have a greenish hue, as if tinted by a mineral which varies from a yellowish to a pale dull green. Small scales of silvery mica and crystals of pyrite are visible. Under the microscope the slide is seen to consist mainly of quartz and felspar, the former predominating.
The Droitwich Brine-Springs and Saliferous Marls
Authors: Parkinson C.
Published: October 2009

T
he
valley of Droitwich lies in the lowest part of a trough, the Upper Keuper Marls partly filling up a deep depression in the lower Trias and Permian rocks. The geographical direction of the valley is from N.E. to S.W., taking a westward turn through the town of Droitwich itself. It is in the Red Marls that brine-springs are met with—a source of considerable wealth to the surrounding population, but, on the other hand, the cause of great depreciation in the value of land and house property within the borough of Droitwich.

As we pass through the town by the Birmingham and Bristol line of the Midland railway, a strange scene of dilapidation lies before us. Every chimney is out of the perpendicular; houses appear to be sinking in, and signs of active subsidence show themselves on every side; the very ground over which the line passes hardly seems safe from a sudden collapse. Standing in the churchyard of Dodderhill, an eminence nearly overlooking the town and valley, it is possible to trace the line of country which is so affected by the extraction of salt, the probable area of the brine-basin of this locality. From the evidence afforded by this subsidence, and from experimental borings, the width of this area does not exceed 300 yards, while the length, so far as has been ascertained, is about 6 miles—this length extending from Stoke, 4½ miles N.E. of Droitwich, to a point not far beyond the town, S.W. or W. The
On Further Discoveries of Vertebrate Remains in the Triassic Strata of the South Coast of Devonshire, between Budleigh Salterton and Sidmouth
Authors: Metcalfe A. T.
Published: October 2009

M
y
special object in making this communication is to bring under the notice of the Society some further vertebrate remains which have been obtained by my friend H. J. Carter, Esq., F.R.S., of Budleigh Salterton, from the Triassic strata of the south coast of Devon, between Budleigh Salterton and Sidmouth, and are now deposited in the Geological Department of the British Museum of Natural History, at South Kensington.

In order to fix the precise geographical and stratigraphical position of these extremely rare and interesting specimens, I propose to commence with a brief reference to the coast section (fig. 1, p. 258).

The Upper Sandstones (following Mr. Ussher’s classification of the Triassic rocks of Devonshire), in which the before-mentioned fossils were found, crop out in the cliffs at Budleigh Salterton. Near their outcrop the beds are coarse and conglomeratic, but they become less and less so as we follow them along the dip towards Sidmouth, which lies about six miles to the east.

About two miles before Sidmouth is reached, the cliffs suddenly rise to the height of 513 feet at a spot called “High Peake Hill,” where the sandstones are capped by the Upper Marls (Triassic), the Upper Greensand, and supracretaceous gravel. The section at this point is approximately as follows:— On the Budleigh Salterton or western side of High Peake Hill is a steep slope leading to a stile on the brink of the cliff, whence a stratum in the sandstones, somewhat lighter in colour than the
On the Volcanic Group of St. David’s
Authors: Blake J. F.
Published: October 2009

The discordant views which at the present moment prevail on the subject of the oldest rocks in the St. David’s district, and the interest which attaches to these rocks according to one at least of the interpretations, induced me, after a visit to the Highland regions on which the same discordance is shown (hut where nature seemed to differ widely from her earlier and disputant interpreters), to attack the St. David’s problem independently, and to stay in the district long enough to come to a conclusion as to the true nature and age of the rocks.

Finding myself in accord neither with Dr. Hicks on the one hand, nor with Dr. Geikie on the other, but led irresistibly to the more simple results so ably shadowed forth by Mr. Hudleston, I cannot refrain from offering to the Society the evidences on which my conclusions are based; as I cannot suppose that the reply which Dr. Hicks will doubtless produce, will represent the same and, as I believe, the true view of the question.

The result of my observations may be thus briefly stated:—all the rocks which have been designated Dimetian, Arvonian, and Pebidian, round and near the city of St. David’s, belong to one volcanic series, whose members are those usually recognized in eruptive areas, and whose age is anterior to and independent of the true Cambrian epoch.

An a
priori
argument in favour of this view is, that it unites the essential features of both the other interpretations; it
On a Recent Exposure of the Shelly Patches in the Boulder-Clay at Bridlington Quay
Authors: Lamplugh G. W.
Published: October 2009

T
he
arctic Molluscan fauna obtained from Bridlington many years ago attracted the attention of many observers, and yielded results of great interest. But though the fauna was carefully studied, the deposit from which it came was comparatively neglected; and as that part of the cliff from which the shells were first obtained was built over, in raising sea-walls for the protection of the town, soon after the bed was discovered, much misconception has arisen as to the nature and position of the deposit. And, the bed being inaccessible to the later workers who established the present system of divisions in our Yorkshire drifts, it came to be described as a
seam
or
bed of shelly sand in place
, in the
Purple
Boulder-clay.

Two years ago, however, I was able to show that neither these shells nor those similarly found at Dimlington, near Spurn Point, had been obtained from beds in place, but from masses of sand and clay occurring as boulders in the
Basement
Boulder-clay. This I endeavoured to prove, not only by evidence collected during the building of a new sea-wall at Bridlington, but also by reference to the accounts of the beds themselves, given by their early investigators.

But as there is still a tendency to hold that the Bridlington shells occurred in place, I am glad to be able to bring forward further evidence bearing on this point, and at the same time to add materially to our knowledge of the fauna of the deposit.

During the
Appendix A. List of Shells obtained from the “Basement” Clay at Bridlington Quay
Authors: Jeffreys Gwyn
Published: October 2009

Observation
.—The species which are not included in the list of Bridlington Post-Tertiary shells furnished by me to the late Professor Phillips, and published in the third edition of his ‘Geology of Yorkshire,’ p. 274, and which are therefore for the first time recorded, are marked with an asterisk. Among these are five species new to science, which will be now described and figured.

In the column after the names of species the letter A. signifies Arctic, Am. American, L. littoral or shallow water (
i.e.
under 100 fathoms), D. deep sea (over 100 fathoms), and sp. n. new species.

The total number of species in the above list is 83, of which 73 are Arctic, 2 are American, 1 only is deep-water, 5 are new to science, and 3 require confirmation as to their being fossil or recent. With respect to
Rissoa costata
and R.
semistriata
, which belong to temperate and southern parts of the North Atlantic, I am not satisfied that they really belong to the glacial bed or deposit above described. Mr. Lamplugh also gives
Thracia pubescens
from similar beds at Dimlington; if correctly identified, this species is not known as living anywhere north of the south of England.

Shell
globosely conical, thick, opaque, and rather glossy:
sculpture
none:
colour
yellowish brown, whitish about the pillar:
spire
short, compressed at the apex or point:
whorls
4, convex, the last disproportionately large:
suture
slight:
mouth
roundish, contracted above and curved below:
outer lip
hemispherical, with a sharp edge:
inner
Appendix D. Note on the Ostracoda and Foraminifera of the shelly Patches
Authors: Crosskey H. W.
Published: October 2009

An examination of the material obtained by Mr. G. W. Lamplugh during the recent exposure of the shelly patches in the Boulder-clay at Bridlington, has both added to the catalogue and confirmed the previously existing evidence of the arctic character of the Ostracoda and Foraminifera contained in that bed.

In making this examination, I have to acknowledge the valuable assistance I have received from Mr. G. S. Brady, with respect to the Ostracoda, and from Mr. H. B. Brady with respect to the Foraminifera. From the facts to be narrated it would appear that the new exposure reveals the same deposit as that to which the name of Bridlington Crag was given when it was first observed; and Mr. Lamplugh informs me that its position on the beach agrees exactly with the early accounts.

In order that the general character of the group of Ostracoda may be clearly understood, it is necessary to refer to the investigations that have already been made, especially since the identity of the newer and older exposures is a point of importance.

In the “Monograph of the Tertiary Entomostraca of England,” by T. Rupert Jones, two species of Ostracoda are described, for which Bridlington is the only locality given, viz.
Cythere concinna
, Jones, and
Cytheridea Sorbyana
, Jones. Neither of these species, wrote Mr. Sorby, “have been met with any where else either living or fossil.”

Since the date of these publications both
Cythere concinna
and
Cytheridea Sorbyana
have, however, been found living as far north
On a Labyrinthodont Amphibian (
Rhytidosteus Capensis
) from the Trias of the Orange Free State, Cape of Good Hope
Authors: Owen Richard
Published: October 2009

I
n
the year 1837 I examined, microscopically, the structure of certain teeth from the sandstone of Guy’s Cliff, Warwickshire, which had been submitted to me by their discoverer, Dr. Lloyd, F.G.S., of Leamington, the form of these teeth being that of simple canines. The well-marked and peculiar structure, so discovered, and the geological correspondence of the matrix with the Keuper of Germany, induced me to apply to Prof. Jäger of Stuttgart (whose acquaintance, ripening into friendship, I had formed at the Meeting of the German naturalists in 1835, under the presidency of Oken, at Freiburg im Breisgau) for a tooth, or portion of tooth, of a fossil in his collection.

To this I was moved by the fact that Jäger had described certain remains from the Keuper of Württemberg, as of a Saurian reptile, under the name of
Mastodonsaurus
, and it was to the teeth of this species that I wished to apply the microscopic test.

My friend at once transmitted a tooth of this ancient reptile, and I was gratified to find therein the same peculiar structure which had led me to apply the generic term ‘
Labyrinthodon
’ to the extinct species represented by the Warwickshire fossil tooth: this result was communicated to the Geological Society.

The batrachian or batrachoid character of the extinct possessor of teeth of this complexity was subsequently inferred from the structure of the bony palate in a portion of skull, also from the Keuper of Warwickshire, described and figured in a later paper under the
A Comparative and Critical Revision of the Madreporaria of the White Lias of the Middle and Western Counties of England, and of those of the Conglomerate at the base of the South-Wales Lias
Authors: Tomes Robert F.
Published: October 2009

T
he
purpose of the present paper is a twofold one—to point out the identity of certain Madreporaria from the Rhætic White Lias of Warwickshire and the Western counties with species from the South-Wales Liassic Conglomerate, and to show that a greater number than has been supposed are identical also with corals from the St. Cassian beds.

In 1878, when my paper on Liassic Corals was published in the Society’s Journal, I thought I had exhausted the whole of the material at command. However, a recent examination of Prof. Duncan’s types of species of Madreporaria from the Glamorganshire Lias, collected by the late Mr. Moore, and now in the Bath Museum, and the acquisition of a considerable collection made at Sutton during the present year (1883) by my friends Mr. W. C. Lucy, F.G.S., and Mr. T. J. Slatter, F.G.S., and by myself, has led me to re-examine the several species. The results of such examination I now lay before the Society; but before doing so, it is desirable that I should briefly notice the several papers which have appeared on the subject. Unfortunately the greater part of them are so far controversial, and even contradictory within themselves, as to render their conclusions, to say the least of it, far less valuable than they otherwise would have been.

The present observations were made upon a small but thick slice of obsidian from Java, given me some years ago by Prof. W. Chandler Roberts. On examining this section under the microscope, in
On the Dyas (Permian) and Trias of Central Europe, and the true Divisional Line of these two Systems
Authors: Irving A.
Published: October 2009

I
n
bringing this subject before the Society, it is my intention merely to follow up and supplement that treatment of the questions involved which, through the courtesy of the Editor of the Geological Magazine, I was able to apply to them (more especially for the British rocks) during the year 1882. I shall assume that what I have written in that periodical is familiar, or at any rate accessible, to all Fellows of the Society who are interested in the question herein discussed. This paper was written, for the most part, last summer in Germany, and some of the facts were given briefly to Section C of the British Association at Southport. I must express my grateful acknowledgment of the aid which has been courteously given me by geologists of high standing on the Continent, in particular by Prof. Geinitz, Dr. Franz Fitter von Hauer, and Dr. Liebe. I am also greatly indebted to the Museums of Dresden and Freiberg, and to the Geologische Reichsanstalt in Vienna.

Without committing myself to a definite advocacy of a substitution of the name Dyas for the name Permian, I must be allowed briefly to point out that it is not a mere question of names. The Permian system of Murehison was essentially a tripartite one, and in applying it to the rocks of central Europe (and to those of the British area) he raised the question of the true position of certain thin-bedded sandstones and marls (Sand- and Mergel-schiefer of German writers), which
Notes on the Microscopic Structure of some Rocks from Guernsey
Authors: Bonney T. G.
Published: October 2009

I
n
describing the specimens which Mr. Hill has selected and forwarded to me for microscopic examination, it will be convenient to group them lithologically rather than geographically. We will take first a series illustrating the gneiss, which occupies three fourths of the whole area of the island. These slides indicate that this region is occupied by a series of coarsely crystalline, rather granitoid gneisses, which have a general lithological resemblance to the more typical varieties of the Hebridean group of Scotland. It cannot, I think, be doubted that we have exposed here in the Channel Islands a fragment of the foundation stones of the earth, of rocks roughly corresponding in age with those that on the continent of America have been named Laurentian. A lengthy description is needless, as so many accounts have now been published of rocks of this character; enough to say of these, as a whole, that while indubitably not igneous, they do not generally exhibit a very marked foliation. Quartz and felspar are always present, and the third predominant mineral is usually a brown mica; the quartz, as seems to be commonly the case in these old gneissic rocks, is rather full of enclosures, many of which are certainly cavities. These vary much in form, some being very irregular, others rounded in outline. Bubbles are not seldom present, but a good many cavities appear to be empty. The felspar is usually somewhat decomposed and occasionally so much so as to make it difficult to conjecture the
Studies on some Japanese Rocks
Authors: Koto Bundjiro
Published: October 2009

T
he
materials for this paper were kindly sent to me by Mr. T. Wada and Mr. Kato, Rector of the Tokio University, and were obtained partly from the petrographical collection of the Tokio University and partly from that of the Geological Survey of Japan. During the last few years those districts, in which our rock-specimens were collected, have been examined by 0. Kuntze, E. Naumann, J. J. Rein, and other European geologists, but as yet no full descriptions of their researches have been published. Many specimens belonging to the Geological Survey were collected in the provinces Izu and Kai by Wada, and those from Kojuke during a two months’ journey by myself. The rock-specimens belong mostly to grey porphyritic pyroxene-andesites, basalts, diabases, granites, diorites, and porphyrites.

The microscopic investigations have been prosecuted in the Mineralogical Institute of Leipzig under the direction of Geheimerath. Prof. F. Zirkel, and the chemical analyses were made in the Laboratory of Agricultural Chemistry under Prof. W. Knop, to both of whom I here take the opportunity of expressing my hearty thanks.

P
yroxene-andesites
.

The andesitic rocks were for the most part collected in the neighbourhood of Tokio and in the province of Izu, the latter a mountainous volcanic district in which the well-known Atami geyser and many other mineral springs of less note are situated. Most of the specimens belong to the coarse porphyritic type. They are grey or dark-brown in eolour, somewhat porous and with a trachytic appearance. With the aid of simple lens, or
On some Zaphrentoid Corals from British Devonian Beds
Authors: Champernowne A.
Published: October 2009

T
he
authors of the monograph of “The Devonian Fossil Corals,” in the Palæontographical Society’s volume for 1853, described and figured two species only of Devonian corals included in their subfamily Zaphrentinæ, namely
Hallia Pengellii
of those authors, and
Amplexus tortuous
Phillips. Since the publication of that work fresh material has been accumulating, and this will eventually necessitate a complete revision of the Devonian corals, involving, it may be, the admission of some new genera and the fusion of others.

To this end the way has been already paved to some extent by several palæontologists. For example, the genus
Battersbyia
, E. and H., has (metaphorically) had its corallites
extricated
from the so-called “cœnenchyma,” and been classed by Dr. Duncan as a precursor of the aporose corals of the Mesozoic and later ages, under the family Palæastræidae; whilst the “cœnenchyma” itself is manifestly, in various
Battersbyiæ, Stromatopora
of different kinds. Hence the name, though retained, has come to bear a very different meaning from that attached to it by its authors.

In treating therefore of a particular branch of the subject, I have confined myself to noticing, and having figured, the best specimens which are at present available to me; but it must not be supposed that even this branch is brought up to date, as, with two exceptions only, the fossils I shall attempt to describe are all in my own collection, and I have scarcely ventured to go further than that.

With such very disconnected material at hand one can
On the Pre-Cambrian Rocks of Pembrokeshire, with especial reference to the St. David’s District
Authors: Hicks Henry
Published: October 2009

The papers on the Pre-Cambrian Rocks of St. David’s which I communicated to the Geological Society in the years 1876, 1878, and 1879, gave the facts concerning those rocks so far as they were then known. Since then I have revisited that district on several occasions, and have been able to obtain very much additional information in regard to them. Most of this has proved highly confirmatory of my previous conclusions, and it has shown that all the main points insisted upon in those papers are correct. Some of the evidence has tended, however, to cause me to adopt minor modifications of the views expressed; but this is only what I was quite prepared to expect, as further researches were being prosecuted in this and other areas. The growth of the question, so fraught with difficulties at first from its novelty and from the want of that special knowledge which time and experience alone can give, has been, I readily confess, “a process of development during a course of years.” Of this I am not in the slightest degree ashamed; for as my sole object has been to arrive at the truth concerning these rocks, I have always been anxious to correct errors when made clear, as the result of fuller information, and also when they have been pointed out at any time by those whose special experience enabled them to do so.

The additional information now submitted has been gradually accumulated since my last paper was read in 1879;
Appendix.—Notes on the Microscopic Structure of some Rocks from Pembrokeshire
Authors: Davies Thomas
Published: October 2009

Nos. 1–5. These are textural varieties of the Dimetian, Nos. 1 and 2 being from Porth-lisky, Nos. 3 and 4 from Porth-clais, and No. 5 from a quarry south of the Camp. It is difficult to add to the descriptions already given of this rock. The quartz is of a peculiarly dirty aspect, being filled with enclosures, by far the larger portion of which are not fluid, but of a fine dusty nature, resembling much the dusty débris of felspars. It is often of a rounded character, like that of a typical quartz -felsite, and frequently in isolated crystals, surrounded by a mass of what may be immature or undeveloped rather than altered felspar. There is orthoclase and sometimes plagioclase and microcline. No mica is present, but in No. 4 there are evidences of the former presence either of hornblende or of biotite, probably the latter. The green chloritic mineral occupies interstices or fissures, or partly replaces the felspars, and it presents no indication of its having resulted from the decomposition of a micaceous constituent. A rhombohedral carbonate is present in No. 1, which is probably a dolomite. The peculiar dendrito-graphic structure existing between the quartz and the felspar is very striking in Nos. 2 and 3—a rock which, probably from crushing, presents a remarkably brecciated aspect. No. 5 is banded, the darker bands containing much of a fine-grained translucent grey mineral, which depolarizes light.

I may remark here that on a former occasion I thought this rock might be
On the Fructification of
Zeilleria (Sphenopteris) delicatula
, Sternb., sp.; with Remarks on
Urnatopteris (Sphenopteris) tenella
, Brongt., and
Hymenophyllites (Sphenopteris) quadridactylites
, Gutbier, sp.
Authors: Kidston Robert
Published: October 2009

So much confusion has arisen between
Sphenopteris delicatula
, Sternb.,
Sphenopteris tenella
, Brongt., and
Sphenopteris quadridactylites
, Gutbier, that in dealing with
Sphenopteris delicatula
, Sternb., it is also necessary to give a list of the synonyms of the two other species, which, in the barren condition, approach it somewhat closely.

The small-pinnuled members of the genus
Sphenopteris
, Brongt., are, under the most favourable circumstances, from the delicate nature of their fronds, extremely difficult to determine. As they usually occur in a very fragmentary condition, and the segmentation of their pinnules varies considerably according to the position held by the pinnæ on the frond (the pinnules of the upper pinnæ being generally more simple than those on the lower pinnæ), the difficulty of discriminating the species is considerably increased.

When the specimens have suffered any lengthened maceration, the limb of the pinnules usually disappears entirely, and there is nothing but the veins left. In this state, the specific identification of these delicate Sphenopteroids is very unsatisfactory, if not quite useless.

Fortunately the fruit of
Sphenopteris delicatula
, Sternb.,
Sphenopteris tenella
, Brongt., and
Sphenopteris quadridactylites
, Gutbier, is known; and though their barren fronds may possess a considerable likeness, their fructification is very distinct; but even the barren fronds, when well preserved, are sufficiently marked to enable one to determine the species with absolute certainty.

Z
eilleria
, nov. gen.

Involucres borne at the extremities of the pinnule-segments, which are more or less produced to form a pedicel;in the earlier condition the involucres are globular, but at maturity
On a New Species of Conoceras from the Llanvirn Beds, Abereiddy, Pembrokeshire
Authors: Roberts Thomas
Published: October 2009

Whilst working in the Llanvirn series, near Abereiddy Bay, in Pembrokeshire, in June and again in September last, I found some fossils in a quarry which had apparently been but recently opened. This quarry is about half a mile N. of W. from the Llanvirn quarry, which has yielded such an interesting fauna to the researches of Dr. Hicks and others during the last few years, and from which too Prof. Hughes and his students, myself amongst them, obtained a good collection during the last Easter vacation.

The rocks exposed in this new quarry are less fossiliferous than those at Llanvirn, and during both of my visits I succeeded in getting only eleven specimens, consisting of the following species, which Mr. Marr has identified for me:—

Phacops llanvirnensis (?),
Hicks
.

Trinucleus, sp. ?

Glossograptus ciliatus,
Em
.

Didymograptus indentus,
Hall
.

Diplograptus, sp. ?

Conoceras, nov. sp.

Only one specimen of
Glossograptus ciliatus
has been as yet recorded from St. Davids, while
Conoceras
is new to the district.

This
Conoceras
I obtained from one of the workmen in the new quarry, and the character of the matrix in which the fossil is imbedded completely confirms the statement of the quarryman that he had found it there.

The cleavage does not quite coincide with the bedding, and, as a result of this, the plane along which the
Conoceras
is exposed, cuts through
On the Chemical and Microscopical Characters of the Whin Sill
Authors: Teall J. J. H.
Published: October 2009

The term Whin Sill is applied in the north of England to the intrusive sheet of basic igneous rock which forms such a marked feature in certain portions of the Lower Carboniferous district of Durham, Cumberland, and Northumberland. It is unnecessary, on the present occasion, to describe the stratigraphical relations of the rock, because full details are to be found in the papers cited above, and especially in those by Prof. Sedgwick and Messrs. Topley and Lebour. For some time there was a discussion as to whether the rock was intrusive or interbedded, but this discussion may be regarded as having been closed by the publication of the able paper by Messrs. Topley and Lebour. It is now admitted on all hands to be intrusive. To give some idea of its extent, I may mention that it is exposed as an inlier in Teesdale for a distance of many miles. It reappears in the Cross-Fell escarpment in Cumberland, and may be traced thence, with slight interruptions, across the county of Northumberland, to the sea-coast at Dunstanburgh, following in a general way the strike of the beds with which it is associated. As the strike bends round to the N.W. in the northern portion of Northumberland, the Whin Sill reappears on the coast at Bamburgh, and may be traced from this point to Kyloe, where it is last seen.

The distance from the point in the Cross-Fell escarpment, where it first appears, to Dunstanburgh is about 60 or 70 miles. Speaking
Fossil Cyclostomatous Bryozoa from Australia
Authors: Waters Arthur Wm.
Published: October 2009

I have already described in the Journal of this Society the Chilostomatous Bryozoa from Curdies Creek, S.-W. Australia (vol. xxxvii.), Mount Gambier, South Australia (vol. xxxviii.), Bairnsdale, Gippsland (vol. xxxviii.), and Muddy Creek, Waurn Ponds, and Bird Rock, Victoria (vol. xxxix.). But the Cyclostomata I kept back, in order to deal with them all together; and since I completed my last paper I have received for description from Prof. Tate an interesting collection from Murray Cliffs and Aldinga, South Australia, and all are now considered together. I have also in my hands a collection of fossils (belonging to Miss E. C. Jelly) from Napier, New Zealand, to which I allude in the text.

The determination of the Cyclostomata presents much greater difficulties, and is much more unsatisfactory than that of the Chilostomata, as there are fewer characters which can be used, so that classification has been made to depend principally upon the mode of growth—a character which has frequently proved of no value in the Chilostomata. Until within a recent period this was in both considered the main characteristic; but now, thanks to the labours of Smitt, Hincks, and other recent workers, it has been shown to be of secondary importance in the classification of the Chilostomata, swhich, however, possess many distinctive characters, such as the form of the cell or zoceeium, together with the shape of the aperture (which is, perhaps, best indicated by the shape of the operculum) ; the presence, in a large number of cases, of
On some Fossil Calcisponges from the Well-Boring at Richmond, Surrey
Authors: Hinde George Jennings
Published: October 2009

Subsequent to bringing before the Society the description of the strata penetrated in the Richmond well-boring, Professor Judd submitted to me for examination some small fossils of dubious character which had been met with in one of the bands of calcareous shale intervening between the beds of oolitic limestone at a depth of 1205 feet beneath the surface. These fossils were associated with remains of Brachiopods, Polyzoa, and other small organisms, and presented a similar aspect of fossilization, being throughout calcareous in composition. The exterior surface of these bodies exhibits a network of delicate fibres with minute interspaces resembling that of calcisponges of Zittel’s family Pharetrones. In several specimens the basal portion was covered with a delicate, more or less wrinkled membrane, and on close observation with a strong hand-lens minute three-rayed spicules could be seen here and there on the surface of this membrane. This fact, at once conclusive as to the real Sponge-character of these forms, was farther supplemented by the microscopic examination of transparent sections of the fibres, in which a spicular structure can be readily detected. In all, about 45 examples of these bodies were found in the shale examined; and an idea may be formed of their small dimensions from the fact that the entire number can well be contained in a tea-spoon. The smallest specimen measures only 2·5 millim. in diameter, and the largest 10 millim., or about two fifths of an inch. In respect to size they more nearly resemble their existing analogues
On the Structure and Affinities of the Family of the Receptaculitidæ, including therein the
Genera
Ischadites
, Murchison (=Tetragonis, Eichwald); Sphærospongia, Pengelly; Acanthochonia, gen. nov.; and Receptaculites, Defrance
Authors: Hinde George Jennings
Published: October 2009

Amongst the Palæozoic fossils whose characters differ to such an extent from those of existing organisms that great differences of opinion as to their affinities have been expressed by the various palæontologists who have studied them, the above-named genera occupy a prominent position. They have been assigned in turn to pine-cones, Foraminifera, Sponges, Corals, Cystideans, and Tunicate Mollusca; but after all that has been written on them, such competent authorities as Ferdinand Romer and Zittel agree in stating that they form an altogether uncertain group of organisms, which, though ranged provisionally amongst the Foraminifera, have hardly a single typical character in common with them. Under these circumstances a fresh attempt to interpret their structure will not be inappropriate; and though the new facts which I have to bring forward do not make any very important additions to those ascertained by previous students of the group, they at least furnish, in my opinion, striking evidence in favour of the affinity of these forms to Sponges. This relationship has already been strongly advocated by the late Mr. Billings; and though the basis of comparison which he instituted between the structure of
Receptaculites
and the gemmulæ of freshwater sponges cannot now be maintained, yet in regarding the former as a sponge, Mr. Billings showed, in my opinion, a clearer insight into its systematic position and structure than later authorities, such as Prof. Gümbel and Dr. Dames, who have ranged it with Foraminifera.

The materials which have served as the foundation for the following
Note on a Section near Llanberis
Authors: Green A. H.
Published: October 2009

Those geologists who hold that the quartz-felsites between Llanberis and Caernarvon are of Pre-Cambrian age, rest their belief mainly on the fact that the conglomerate which they take to be the base of the Cambrian rocks in that district contains numerous pebbles of this felsite. It would be very desirable to have this inference confirmed by direct evidence of stratigraphical unconformity between the two rocks; but I do not know that any one has been able to point to a section where that conglomerate is seen actually resting on the felsite, and where there is an unconformity at the junction. The section which I wish to describe, and which seems to have escaped the notice of the geologists who have from time to time during the last few years reexamined the district, does show the conglomerate resting with the most marked unconformity on a lower group of rocks; and it is for this reason that I call attention to it. I saw the section first in the summer of 1880, and visited it again during the summer of the present year.

The section is found in one of the cuttings of the railway which runs from the Dinorwig quarries along the north-eastern shore of Llyn Padarn; to show its position with respect to the adjoining rocks, I have plotted, in fig. 1, the section along the railway from some distance on either side of it. We start at the south-eastern end in the bottom beds of the slaty series which
On some West Indian Phosphates
Authors: Hughes George
Published: October 2009

From the specimens of West Indian phosphates and coral I have the privilege of bringing under your notice, I desire to direct your attention to the fact that, under certain conditions, it is possible for coral-stone to be converted into phosphate of lime. Dana, in his work on Corals and Coral-islands, speaking about the formation of Howland's Island, says: “Some interesting pseudomorphs occur buried in the guano of this island. Coral fragments of various species were found that had long been covered up under the deposit, and in some of which the carbonic acid had been almost entirely replaced by phosphoric acid. In such I have found 70 per cent. of phosphate of lime. In many others the change was only partial, and on breaking some of these, in the centre was usually found a nucleus or core of coral still retaining its original hardness and composition, while the external parts had been changed from carbonate to phosphate, which, though soft and friable, still preserved the structure and appearance of the coral.”

My attention was first directed to this fact in the island of Barbuda, where I found a small vein, rich in phosphate of lime, starting from the bottom of a cave in the face of a coral cliff. The earth in this cave consisted of phosphatic guano formed from excrement of bats, and similar in composition to the earth that is generally found in tropical caves. The water draining from this guano-earth must have contained phosphoric acid in
Notes on Species of
Phyllopora
and
Thamniscus
from the Lower Silurian Rocks near Welshpool, Wales
Authors: Vine George Robert
Published: October 2009

Mr. G. W. Shrubsole, in a paper “On the Occurrence of a new Species of
Phyllopora
in the Permian Limestone”, remarks that “the genus
Phyllopora
has as yet been but imperfectly worked; its rarity in the more recent and its imperfect preservation in the older rocks go far to account for this..... In the Lower Silurian rocks
Phyllopora
is most abundant. There are at least two distinct species, if not more. The preservation of the remains in these beds is most unfavourable for exact work, occurring, as they often do, in coarse ash or shale, and distorted by cleavage.”

In the collection of the School of Mines there were several specimens of
Phyllopora
catalogued and labelled as such, which I was allowed to examine when collecting material for my Second British Association Report on Fossil Polyzoa. The specimens from the Lower Llandeilo rocks are the common forms, generally designated
Retepora
by early authors. One specimen is in the Wyatt-Edgell collection, and we have only the reverse aspect of the form; but in places where the branches are worn the cells can be seen, not sufficiently, however, to enable us to make out their character. The fenestræ are oval or irregular, branches anastomosing, consequently without dissepiments.

In the Caradoc series of fossils of the same collection, several specimens are labelled, and also catalogued, as
Phyllopora Hisingeri
, M'Coy, and one, belonging to the Wyatt-Edgell collection, is catalogued as
P. ornata
, MS. Generally speaking, all these forms are very indistinct or ill-preserved. In