bluuebunny/crossref_metadata_2025 huggingface dataset:
On
Ailurus anglicus
, a new Carnivore from the Red Crag
Authors: Dawkins W. Boyd
Published: October 2009

§I. Introductory.

In the fine collection of fossils from the Crag of Norfolk and Suffolk, presented to the Museum of the Yorkshire Philosophical Society at York by Dr. Reed, is a battered and water-worn specimen, which is of singular interest, because it carries the range of one of the most restricted of the genera of the Oriental Province far to the west and to the north of its present habitat. It is a small fragment of the right lower jaw, with the last true molar in position, found in the Red Crag of Felixstowe, the rest of the ramus and the angle and articular and coronoid processes being broken away (see figs. 1 and 2).

§2. Description and Comparison with Ailurus fulgens.

After a long and careful study, I find that the lower jaw in question differs in a marked degree from all the European fossil Carnivores, and presents no important points of difference when compared with the series of jaws of recent
Ailurus
in the British Museum.

The last true molar in the fossil is implanted in the jaw by two fangs, the anterior being the smaller, and supporting the anterior cusps,
A
and
D
of figures 1, 2, 3, 4. The multicuspid crown is composed of three small, obtusely pointed cusps,
A, B, c
of figs. 1, 3, and 4, on the outer side, while the inner (figs. 2 and 3) is occupied by the large cusp
D
and a smaller hind cusp
F
, connected by a line
Note on the Movement of Scree-Material
Authors: Davison Charles
Published: October 2009

The slope of screes being, as a rule, not much under the greatest angle at which it is possible for their component material to rest, it follows that a very slight force is in general required to put the surface-stones in motion. This is evident, too, from the number of stones dislodged when a block falls down from above; also from the difficulty experienced by persons in trying to cross them. “Every movement,” says Scoresby, describing the descent of a mountain covered with loose stones in Spitzbergen, “was a work of deliberation. The stones were so sharp that they cut our boots and pained our feet, and so loose that they gave way almost at every step, and frequently threw us backward with force against the hill. We were careful to advance abreast of each other, for any individual being below us would have been in danger of being overwhelmed with the stones, which we unintentionally dislodged in showers”†.

The instability of scree-material being so great, the causes of its motion are consequently numerous. Many have at various times been pointed out, more especially in considering the origin of different accumulations of angular débris, such as the limestone-breccias of Gibraltar or the stone-rivers of the Falkland Islands, the main difficulty in these cases being, however, to account for the transport of the material over surfaces inclined at a small angle. References to these well-known discussions are perhaps hardly necessary, it being the object of this paper to call attention
On the Cambrian and associated Rocks in North-west Caernarvonshire
Authors: Blake J. F.
Published: October 2009

Introduction.

The area to which the present memoir refers has for a long time attracted the attention of geologists, partly because within it may be found the oldest portion of the Cambrian series, and therefore the supposed base of our known stratified rocks, and partly because, of late years, there has been an expectation of finding here some representatives of still older series.

The most recent observers, indeed, agree in regarding the whole of the mass coloured as porphyry between Bangor and Caernarvon, and some part of that coloured altered Cambrian, as belonging to a Pre-Cambrian epoch, and the felsite of Llyn Padarn and Moel Tryfaen they treat in the same way. There is no difference of opinion between them on this latter area, but as to the former, though all divide the mass into three parts—the mass near Caernarvon, the mass near Dinorwic, and that near Bangor,—Prof. Hughes considers all three a connected series of “beds,” Prof. Bonney regards the Caernarvon rock as very old, and the other two as connected, while Dr. Hicks regards them as representing three independent and unconformable groups. Again, Prof. Bonney and Prof. Hughes differ as to the stratigraphy near Bangor, with the effect that the former considers much more to be Pre-Cambrian than the latter does. All three views are diametrically opposed to that of the Survey, not only as to theories but as to many of the facts. Nor has the Survey given way. Prof. Ramsay, in 1881*, says the proposed changes
An Estimate of Post-Glacial Time
Authors: Reade T. Mellard
Published: October 2009

Of late several attempts have been made to show that the close of the Glacial period was very recent.

Having personally devoted considerable attention to what is called Post-glacial or “superficial” geology, I am much struck with the imperfect knowledge with which the question of Post-glacial time is frequently approached.

The writers seem to be unaware of, or to insufficiently appreciate, the grand sequence of events recorded in the deposits on the Lancashire and Cheshire coasts which have taken place since the snow and ice of the Glacial period disappeared.

On the borders of the coast-line between the Dee, the Mersey, and the Ribble, the student who cares to pursue the subject can do so with great advantage. But through the horizontality of the deposits, and their general low level, none occurring above the level of the 25 feet Ordnance datum and all reaching down to below the level of the lowest spring-tides, the study has to be pursued through the medium of excavations and borings. This I have done in observations extending over many years, and I now propose to show their bearing upon the absorbing question of recent geological time.

Denudation of the Low-Level Marine Boulder-clay.

The whole of the country to which these notes specially refer was formerly entirely covered with a mantle of Low-level marine Boulder-clay and sands. These I have described at length in several papers.

That the valleys of the Dee, Mersey, and Ribble were at one time filled with Low-level marine Boulder-clay, we
Notes on Rock-specimens collected by Mr. Fox from the Islands of the Lizard Head
Authors: Teall J. J. H.
Published: October 2009

The two small islands of Mên Hyr and Vasiler lie half a mile due south of Polpeor. A line drawn between these islands in a N.W. by W. direction passes through the Clidgas Rocks, the Man-of-War Rocks, and the Stags. These islands, together with Taylor's Rocks and Mulvin, which lie slightly to the south-west of the above line, constitute what may be termed the Outer Group. Inside these we have Enoch Rock, Pen Ervan, Labham Reefs, Labham Rocks, Mên Par, the Shag Rock, Wiltshire, the Quadrant, and Sanspareil. We will now describe the rocks from the different islands, taking the latter in the order mentioned.

Outer Group.

Mên Hyr
.—A coarse gneissose rock showing a marked foliation. Dark lenticular patches, rich in ferro-magnesian minerals, alternate with light-coloured patches of similar form composed of quartz and felspar or pseudomorphous substances after felspar. Under the microscope the rock is seen to be composed essentially of felspar, quartz, dark mica, and hornblende. The felspar is so altered in places as to have lost all individual action on polarized light; it is then represented either by aggregates of a vividly polarizing scaly mineral (mica) or by patches which appear opaque by transmitted, and snow-white by reflected light. The unaltered felspar is abundant in certain portions of the slide; the larger grains are mostly striated. Quartz occurs in grains and granular aggregates. The quartz and felspar in certain portions of the slide exhibit the relations characteristic of igneous rocks; in others they form a fine-grained granulitic
On the Probable Mode of Transport of the Fragments of Granite and other Rocks which are found imbedded in the Carboniferous Limestone of the Neighbourhood of Dublin
Authors: Ball V.
Published: October 2009

For some time I have been endeavouring to obtain specimens of the limestone containing fragments of granite which were first found nearly forty years ago in the neighbourhood of Dublin. The quarries being now filled up and inaccessible, I followed on the track suggested by having observed a specimen built into a garden wall, and through the aid of Mr. H. B. White, M.E., I was enabled to discover a wall in which such specimens occurred in considerable abundance. The permission of the owner, Dr. E. P. Wright, having been obtained, a fine series of blocks, in which the granite was visible, was delivered at the museum; these, after they had been trimmed and split by a stone-mason, afforded such a variety of beautiful specimens that I have thought it would interest the Society to exhibit a selection of them, as I believe comparatively few geologists have had an opportunity of examining anything of the kind.

The examination of these specimens has revealed the presence not only of angular fragments of granite but also of schist, quartzite, and vein-quartz, such as might have been derived from the metamorphosed Silurian rocks which rest on the granite near Dublin, and are in one locality exposed in a sea-cliff at the base of Killiney hill. As a rule, these fragments, though in some cases permeated with calcareous matter, show little if any signs of of decomposition; the surfaces of contact with the enveloping limestone are sharp and clean, and the adhesion is very
On the Monian System of Rocks
Authors: Blake J. F.
Published: October 2009

Introduction.

Is there no order in Pre-Cambrian rocks? Do they consist in one area of great undulating masses of gneiss, in which those who have studied them refuse to recognize any stratigraphical sequence, and in another of tiny fragments of formations, two or three of which may be contained within an area of a few square miles ? and are these types in no way connected ? Such were the questions which forced themselves upon me after brief consecutive visits to the Highlands and St. David's. Consulting my friend Dr. Callaway on these points, he advised me to go to Anglesey, where I should find rocks that might fairly be compared with the gneiss of the Highlands in character, in close proximity to, if not associated with, volcanic rocks of the type of St. David's. I went; and after three years' work in summer and spring vacations have arrived at conclusions which I now venture to lay before the Society.

But in the forefront of this inquiry we are met by the fact that Sir Andrew Ramsay, who knows the district as one knows one's native hills, has declared that there are no Pre-Cambrian rocks in Anglesey at all. Can we ignore this fact? or must we not first ascertain the reasons which have led to this conclusion ? If after a study of the area, sufficiently prolonged to place one's self somewhat on a level with his knowledge of the rocks, one reads his words, they strike one as
On the Spheroid-bearing Granite of Mullaghderg, Co. Donegal
Authors: Hatch Frederick H.
Published: October 2009

On returning from a recent inspection of the field-work of the Geological Survey in Ireland, Prof. A. Geikie brought with him some remarkable specimens of spheroidal concretions, which, on account of their interesting structure, he thought worthy of detailed examination and description. For this purpose they were entrusted to me, and the present paper records my observations.

These bodies were found by Mr. J. R. Kilroe, of the Geological Survey of Ireland, in granite at Mullaghderg, Dungloe, Co. Donegal. According to Mr. Kilroe, they occur in a mass, measurig 5 or 6 cubic yards, which lies in coarse granite. It consists “of concretionary balls, varying in size up to 6 inches in diameter. The balls are usually flattened and lie almost contiguously, the interstices being filled by granite, which is similar in character to, though muchfiner-grained than, that surrounding the entire mass.”

In a letter I have since received from Mr. Kilroe he informs me that dykes are numerous in the locality where the spheroids occur. One of these passes quite close to the mass containing the concretions; but since the latter are confined to a small space and do not follow the dyke, I see no reason for connecting their formation with its intrusion.

The Normal Granite.—Of the granite referred to above, Mr. Kilroe was kind enough to furnish me with specimens.

It is a coarse-grained rock, varying in colour from a pale fleshtint to a reddish brown. The specimens in my possession have a somewhat loose and crumbly
The Upper Eocene, comprising the Barton and Upper Bagshot Formations
Authors: Gardner J. Starkie , Keeping Henry , Monckton H. W.
Published: October 2009

T
he
introduction of the Oligocene stage into our classification has necessitated a partial revision of the grouping of our older British Tertiaries. Whether this introduction of a new primary division into the Tertiary system was necessary or expedient may still be questioned; but it has been generally adopted and is, for the time being, established. The division does not coincide in England with a marked change in either fauna or flora, though the series seems nevertheless tolerably complete and well developed; its limits, however widely stretched, show that the Oligocene stage compares neither with the Eocene nor the Miocene in importance.

Opinions have differed as to where the line of division should be drawn; whether this should be as low down as the top of the Barton Beds or at the base of the Headon Beds, or even higher. For our part, we think it desirable to uphold the view which places the demarcation between the top of the Bagshot Sands of Alum Bay and the base of the Lower Headon Series, though it is perfectly obvious that any such line in the midst of our series must be a purely artificial one.

An almost necessary consequence of the change in the classification has been the readjustment of the divisions of our truncated Eocene, only the middle and lower division remaining, so that the term “Middle” without, an Upper Eocene would no longer be an appropriate one. But the Middle Eocene, embracing as it does such formations as the Nummulitic
The Stockdale Shales
Authors: Marr J. E. , Nicholson H. A.
Published: October 2009

§1. Introduction.

We propose, in a series of papers, to supplement the observations which have been previously published upon the divisions, organic remains, and subdivisions of the Lower Palæozoic Rocks of the Lake-district and adjoining areas. In the investigation of the geological structure of any such complicated region as the Lake-district, the first step necessarily consists in the determination of those rock-divisions which are developed in the area in question to an extent which renders them capable of representation on the one-inch map of the Ordnance Survey. When the first step has been satisfactorily accomplished, the
general
structure of the region may be said to be determined; but there may, nevertheless, remain many points of great geological interest and importance which still require solution. Thus, it is now generally recognized that in any region a set of deposits may have been formed so slowly that a thickness of only a few feet of such may mark a lapse of time represented elsewhere by many hundreds of feet of sediment. In such cases a more minute subdivision of the strata than can be represented upon an ordinary geological map becomes necessary, and it is also essential to enter into a detailed examination and comparison of the organic remains of the different beds. By this method of investigation very important results have already been obtained in other regions, and we see no reason to doubt that the application of the same method to the study of the Palæozoic Rocks of the Lake-district will result
On the Occurrence of Marine Fossils in the Coal-measures of Fife
Authors: Kirkby James W.
Published: October 2009

This paper records the discovery of fossils of good marine types in the Fifeshire Coal-measures. Reference is also made to the occurrence of similar fossils in the same formation elsewhere.

The Fifeshire Coal-measures form a comparatively small field on the north shore of the Firth of Forth, where they abut on the coastline from Dysart eastward to Largo. They extend only two or three miles inland where the field is widest. On the west they are bounded by outcropping beds equivalent to Millstone-Grit; on the north by faulted strata of the Carboniferous-Limestone series. On the east and south they are bounded by the sea, beneath which they dip. Including an upper set of red beds (

d
5′

of the Geological Survey maps), there is a thickness of over 2000 feet of these measures; but all the workable coals are in the lower portion (

d
5

of the Geological Survey maps): see vertical section at p. 748.

The prevailing fossils of this coal-field are those always characteristic of the formation in other districts. The flora is essentially the same as in the North of England. Among the animal fossils usually met with are
Anthracosia acuta
,
Anthracomya modiolaris
,
Anthracoptera carinata
, and other Lamellibranchs of this family.
Spirorbis carbonarius
is the common Annelid. The Ostracods consist of various species of
Carbonia
, with
Beyrichia arcuata
; with them also occurs the phyllopod
Leaia Leidyi
. Among the fish are
Megalichthys Hibberti
,
Strepsodus sauroides
,
Diplodus gibbosus
, and well-known species of
Ctenodus, Cœlacanthus, Rhizodopsis, Acanthodus, Palœoniscus
, &c. The Amphibians
Loxomma
On the Occurrence of
Elephas meridionals
at Dewlish, Dorset
Authors: Fisher O.
Published: October 2009

In the year 1877 I saw in the Blackmore Museum at Salisbury two molars of an elephant, labelled “Dewlish, Dorset.” I at once attributed them to
E. meridionalis
, and they interested me much, because I had been lately engaged upon the geology of Norfolk only in the pre-glacial Forest-bed of which county, so far as I was aware, that species had been found in this country. It was not, however, till the autumn of the year 1887 that I obtained any information upon the subject, when Mr. E. Cunnington, of Dorchester, told me that large bones had been lately found at the same place; and he gave me an extract from an old notice by the late Mr. Hall, a local antiquarian, that a memorandum of the original find of these remains was published in the ‘Monthly Magazine’ for May, 1814, in which Mr. Hall states that “there is a hill in the parish of Dewlish which was always supposed to be formed of chalk only; but last summer (1813), about 100 feet above the level of the foot of the hill, some sand was observed to be drawn out by a mouse, It was taken notice of, and General Michel [the proprietor of the land] sent workmen to seek for sand.” At about 5 feet below the surface they found the teeth of the elephant, of which two are now exhibited. The section observed by Mr. Hall is recorded below. His description of the fossil remains is diverting.

Mr.
On the Sudbury Copper-Deposits
Authors: Collins J. H.
Published: October 2009

The extensive deposits of copper-ore in the neighbourhood of Sudbury, to the north of Georgian Bay on Lake Huron, have attracted a great deal of attention during the past two years.

The geological and mineralogical characters of the Huronian rocks of the Sudbury district were described by Prof. Bonney in a paper read before the Geological Society of London in November of last year. The copper was discovered about the time of his visit; but as he does not refer to it in his paper, I presume his attention was not called to it. At first it was thought to be an immensely important discovery, likely to revolutionize the copper-trade, and to reduce the price of copper, then, and for a long time after, only £40 per ton, to a figure which would render such mines as Rio Tinto, Calumet and Hecla, and Anaconda quite unremunerative. One of the deposits, the Stable Mine, which had been tested by a series of shallow trial pits, was reported to consist of “a mass of solid sulphides of copper and iron, 1600 ft. long and 1200 ft. across,” the depth being supposed practically unlimited. The description (published only a few months before my visit in October 1887, but written some time before) runs accurately enough as follows:—“It is in the form of a wide round hill, covered, like the surrounding region, with burnt trees, and in appearance it does not differ in any way from the other low hills around, except in the
On the Remains and Affinities of five Genera of Mesozoic Reptiles
Authors: Lydekker R.
Published: October 2009

Introductory.

The following communication treats of certain remains referred to four species of English Mesozoic Reptiles, some of which were first described or named by Professor H. G. Seeley, and also includes a discussion as to the affinities of a fifth form. The substance of that portion of the paper relating to
Peloneustes philarchus
was previously brought under the notice of the Society at the Meeting held on May 23rd as a separate communication, entitled “On the Skeleton of a Sauropterygian from the Oxford Clay near Bedford”, but, on account of a change of view on the part of the Author, it was considered advisable that it should be again presented in a revised form.

Vertebræ of an Ornithopodous Dinosaur from the Canbridge Greensand.

On page 621 of a memoir on the remains of Dinosaurs from the Cambridge Greensand, published in the 35th volume of the Society's 'Journal,' professor Seeley applied the name Syngonosaurus macrocercus to a series of nineteen vertebræ from the cervical, dorsal, sacral, and caudal regions, which were said to be associated, and indicate a medium-sized species. At the conclusion of the description of these vertebræ mentions is also made of csrtain dermal scutes. which it was suggested might also be associated. I have no intention of entering into the question whether the alleged association of all these remains is absolutely certain, and I shall accordingly confine my remarks to the one cervical and eight dorsal vertebræ, which, as being the first described (although not figured), may,
Description of a new Species of
Clupea
(
C. vectensis
) from Oligocene Strata in the Isle of Wight
Authors: Newton E. T.
Published: October 2009

Mr. G. W. Colenutt, of Ryde, has recently been investigating the Oligocene strata of the northern parts of the Isle of Wight, and an account of his researches appeared in the August number of the ‘Geological Magazine’. Among the numerous fossils he has obtained from these deposits, none are more interesting than the small fishes which occur, apparently in some numbers, in a grey shaly clay belonging to the “Osborne Series,” at King's Quay and other localities. The best examples, which Mr. Colenutt kindly sent me for examination, vary in length from 20 to 60 millimetres. Most of them have the back concave and the mouth wide open, seeming to indicate that they died in a state of tetanus, probably due to asphyxiation, as their condition is very similar to that of fishes which have died from being kept in too small a quantity of water.

Many of these fossil fishes are beautifully preserved, with the vertebral column, ribs, fins, and tail in their natural positions. The heads also are present, but unfortunately they are all more or less mutilated, so that the forms of the bones cannot be well deciphered.

The large examples, of which there are tour well preserved (Pl. IV, figs. 1, 2, 3), measure from 43 to 58 millimetres in length. These vary somewhat in form, as will be seen from the examples figured; but this is probably due to pressure, as they seem to be precisely alike in other particulars. The single dorsal fin has
On
Archæocyathus
, Billings, and on other Genera, allied to or associated with it, from the Cambrian Strata of North America, Spain, Sardinia, and Scotland
Authors: Hinde George Jennings
Published: October 2009

The real characters and the relations of the group of fossils known generally under the term
Archæocyathus
are at present subjects of discussion among palæontologist; they have been regarded as allied to Foraminifera, Sponges, and Corals. Many of the forms occur in the lowest fossiliferous zones of the Canbrian rocks, and are thus among the earliest known forms of life, a fact which gives additional interest to their study. Since Mr. Billings first called attention to them in 1861, they have been investigated by several authors, more particularly by Sir J. W. Dawson, Prof. Ferd. Römer, Mr. C. D. Walcott, and, more recently, by Dr. Bornemann; but it cannot be said that the obscurity attaching to them has been fully cleared up. I have been induced by Sir J. W. Dawson to undertake an independent investigation of their characters, based more particularly on their microscopic structure, and thanks, to the kindness of the above-named authors, I have been supplied with material which has enabled me to ascertain by direct comparison the nature of these fossils from widely separated localities. Thus Sir J. W. Dawson sent some specimens from Labrador belonging to McGill College Museum; the Geological Survey Of Canada, through Mr. J. F. Whiteaves, F.G.S., supplied me with the type forms described by the late Mr. Billings; Prof. Ferd Römer with the figured specimens of
Archæocyathus marianus
from spain; and to Dr. J. G. Bornemann I am indebted for fragments of rock filled with these fossils, which he collected in
Note on
Marsupites testudinarius
, v. Schlotheim, sp.
Authors: Bather F. A.
Published: October 2009

Confusion has long reigned supreme in the nomenclature of the genus
Marsupites
. The splendid series of specimens in the collection under my care enables me to attempt the restoration of order with some hope of success. A specimen of
Marsupites
was well figured in ‘Parkinson's Organic Remains,’ ii. pl. xiii. f. 24, and adequately described on pp. 225–-229 of that work. Had Parkinson only named his numerous species according to the Linnean method an enormous amount of subsequent confusion, in this and many other cases, would never have occurred. To many of Parkinson's figures names were given by Von Schlotheim; the one now in question he called
Encrinites testudinarius
. Every form hitherto discovered in the English Chalk belongs without a doubt to the same species as Parkinson's specimen. Between absolutely smooth and extremely rugose specimens there are almost as many gradations as there are specimens. It follows therefore that all other names are synonyms of
M. testudinarius
. This solution of the difficulty is undoubtedly the most satisfactory from a scientific point of view: it is also gratifying to know that the specific name we have to adopt is far more sensible and appropriate than any of its successors, and that, unlike them, it does justice to the enthusiastic observer and delightful describer Parkinson.

The synonymy is as follows:—

M
arsupites
, Miller.

1808. Tortoise Encrinite, J. Parkinson, ‘Organic Remains of a former World,’ Lodon, ii. 225. Parkinson, referring to ‘Nr. Lister's paper on the
Radices entrochorum
,’ says:—“ He there gives an engraving
On the Growth of Crystals in Igneous Rocks after their Consolidation
Authors: Judd John W.
Published: October 2009

Three years ago, in describing some basic igneous rocks from Scotland and Ireland, I expressed my conviction that a part, at least, of the structures known as
micropegmatitic
and
granophyric
were really of secondary origin. At the same time, I stated that these structures were so much more clearly illustrated by the intermediate and acid rocks of the same district that it would be well to defer the discussion of the subject till my examination and description of the rocks in question should be completed.

The study of the intermediate and acid lavas (which, in 1874, I grouped under the old English field-name of “felstones”) and of their plutonic representatives has occupied much of my time and thought during the last fifteen years. But so numerous and interesting are the problems connected with the wonderful metamorphoses which the minerals of these rocks have undergone, and so singular are the changes which have taken place in the structures of these rocks, that, in spite of a number of visits to the district and much labour in the laboratory, some time must yet elapse before the examination of the chief types and the elucidation of their mode of origin is completed.

In the meanwhile, however, certain discussions which have taken place concerning rock-structures and their significance—especially as a basis of rock-nomenclature and classification—render it desirable that the very definite and unmistakable evidence which I have obtained concerning the secondary origin of the characteristic structures of the “granophyric” rocks should be placed on
The Tertiary Volcanoes of the Western Isles of Scotland
Authors: Judd John W.
Published: October 2009

In the year 1874 I communicated to this Society the results of my studies concerning the Tertiary and Older Volcanic rocks of Western Scotland, and their relations to the Secondary strata with which they are so intimately associated*. The very generous manner in which the memoir dealing with those subjects was received by this Society—and especially by those who were at that time the leaders of geological thought in this country—can never be forgotten by me. Such a reception lays upon the author of a memoir certain very obvious responsibilities. In the event of serious and fatal errors being indicated in his observations or reasoning, it is clearly his duty to come forward and frankly withdraw the statements to which this Society has given such wide currency. It is equally incumbent upon him, should his premises and conclusions be openly challenged on what seem to him to be insufficient grounds, to undertake the task of re-examining and, if necessary, of defending his views.

It may not perhaps be out of place to remark that my work in Scotland, to which were devoted five years of heavy labour and careful research, was one that taxed to the full the powers of a private individual. It involved the examination of the physical relations and the discussion of the palæontological characteristics of the whole of the rocks of the Highlands between the Old Red Sandstone and the Glacial deposits. Of these formations, it may be remembered that the strata of Carboniferious and Cretaceous
On prevailing Misconceptions regarding the Evidence which we ought to expect of former Glacial Periods
Authors: Croll James
Published: October 2009

Within the whole range of geological science there is perhaps not a point on which a greater amount of misapprehension prevails than in regard to the evidence which we ought to expect of former glacial periods. The imperfection of geological records is far greater than is generally believed—so great, indeed, that the mere absence of direct geological evidence can hardly be regarded as sufficient proof that the conclusions derived from astronomical and physical considerations regarding former ice-periods are improbable. Nor is this all. Not only are the geological records of ancient glacial conditions imperfect, but this imperfection follows as a natural consequence from the principles of geology itself. There are not merely so many blanks or gaps in the records, but a reason exists in the very nature of geological evidence why such breaks in the record might naturally be expected to occur.

The evidence of Glaciation is to be found chiefly on Land-surfaces.
—It is on a land-surface that the principal traces of the action of ice during a glacial epoch are left, for it is there that the stones are chiefly striated, the rocks ground down, and the Boulder-clay formed. But where are all our ancient land-surfaces? They are not to be found. The total thickness of the stratified rocks of Great Britain is, according to Professor Ramsay, nearly fourteen miles. But from the top to the bottom of this enormous pile of deposits there is hardly a single land-surface to be detected. Patches of real old land-surfaces of
On Remains of Eocene and Mesozoic Chelonia and a Tooth of (?)
Ornithopsis
Authors: Lydekker R.
Published: October 2009

The greater portion of the present communication is devoted to the consideration of Chelonia, and more especially to specimens from the Cambridge Greensand, most of which were collected nearly twenty years ago by my college friend Mr. T. Jesson, F.G.S., of Northampton. It includes, however, the description of an interesting Chelonian from the Wealden, kindly lent to me by the Rev. P. B. Brodie; and also makes certain redeterminations as to the affinities and serial position of some of the marine Chelonians of the London Clay. The tooth from the Wealden referred to
Ornithopsis
leads to the consideration of the affinities of some allied specimens from the Portlandian of France.

1.
The Genus
Rhinochelys,
of the Cambridge Greensand.

The name
Rhinochelys
was applied in 1869 by Prof. H. G. Seeley to the Chelonian cranium from the Cambridge Greensand figured by Sir R. Owen in his ‘Cretaceous Reptalia’ (Mon. Pal. Soc.), pt. i. pl. vii. A, figs. 1-3 (1851), under the name of
Chelone pulchriceps
, of which species it is the type. The distinctive features of this cranium, as shown by the figure, are that the pterygoids, which are in contact throughout their length, are comparatively narrow and emarginate, and that the palatines unite in the median line. There are, moreover, distinct nasals, the prefontals being separated from one another by the nasals and frontals. Again, the temporal fossæ are completely roofed over, after a manner now obtaining only in the Chelonidæ—that is to say, there is both and inferior and
On the Occurrence of Palæolithic Flint Implements in the Neighbourhood of Ightham, Kent, their Distribution and probable Age
Authors: Prestwich Joseph
Published: October 2009

It has hitherto, with a few disputed exceptions, been generally held that, in this country, palæolithic stone implements are confined to “river-drifts” and caves of the so-called Postglacial age, in which they occur buried at greater or less depths; and little search was made outside the drift-deposits, or the valleys to which such deposits are confined. It is true that a few specimens had been found at various heights on the hills, but they failed to attract much attention or to suggest any different explanation. In 1861 Dr. John Evans found a large pointed implement on the surface of a ploughed field in the parish of Abbots Langley, and at a height of 160 feet above the Colne. Another smaller specimen was found in 1861 by Mr. W. Whitaker on the surface of the Chalk, one mile east of Horton Kirby, and about 200 feet above the Darent. In 1869, in searching over a field near the edge of the Chalk-escarpment at Currie Farm, Halstead, Kent, in company with General Pitt-Rivers, Sir J. Lubbock, and myself, Dr. Evans picked up a rude ovoid specimen; but we did not succeed in finding any more. This spot is nearly 600 (not 500) feet above O.D. From time to time a few similar instances have been recorded; but they were either passed by as chance specimens, possibly dropped and lost, or were in some way supposed to be connected with the ordinary river-valley drifts.

But the remarkable discoveries of palæolithic flint implements made
On a Tachylyte associated with the Gabbro of Carrock Fell in the Lake District
Authors: Groom Theo. T.
Published: October 2009

Whilst engaged in studying the igneous rocks of Carrock Fell I observed a peculiar vein of tachylyte traversing the gabbro close to the point at which the latter passes into the granophyre. The vein is about an inch thick, and shows well-marked flow-structure parallel to the sides. The centre of the vein is of a pale greenish colour, and shows spherulitic structure, while on each side is a purplishgrey zone. The rock shows a horny or subvitreous lustre, weathers to a yellowish-brown tint, and is slightly magnetic; under the blow-pipe splinters fuse readily to a black enamel; the hardness is about
3 1/2. The specific gravity of the whole rock is 2·99, while that of the central zone is 2·95. The average density of basalt-glasses is, according to Messrs. Judd and Cole, about 2"7, that of the Scotch varieties varies from 2·72 to 2·89. The specific gravity of Carroek-Fen rock, it will be seen, considerably exceeds the heaviest of them, but appears to approach that of the continental variolites, such as those of Durance or Jalguba

The percentage of silica places the rock high up in the basic series. It appears to have most affinity with the more acid basalts and with the augite-andesites; this agrees with the conclusions formed from microscopical and other evidence, as well as with the fact that the rock is associated with the Carrock-Fell gabbro, which, according to Mr. Teall, is the plutenic representative of the andesitic dolerites. The percentage of iron is unusually high
The Elvans and Volcanic Rocks of Dartmoor
Authors: Worth R. N.
Published: October 2009

In the course of an inquiry into the physical history of Dartmoor, which led to the conclusion that this great granitic upland represents the basal portion of a volcano some 16,000 feet high, special attention was necessarily paid to the felsites or elvans of the district, as filling the gap between the plutonic members of the series, the granites, and the true volcanic rocks no longer found
in situ
. Search for traces of the latter was also made. Hence were gathered the facts now briefly set forth. The less definite term “elvan” is used here in preference to the more distinct “felstone” or “quartz-” or “felsparporphyry,” because the intention is to include under that head all the dyke-rocks of granitoid material connected with the Dartmoor granite; and because it is one of the chief objects of this paper to show that there is no fundamental distinction between the rocks so named, as they occur in the Dartmoor environment, but that different portions of the same dyke may exhibit all these varieties of structure, and present a graduated series between granite and a compact felsite, in which differentiation has yet to be set up. An “elvan” may be any species of rock that has developed from a granitic magma under conditions intermediate between plutonic and volcanic.

One of the first points to attract attention in the inquiry was the great disproportion existing between the characteristic varieties of elvans to be found in situ (I am speaking generally of the southwestern borders of Dartmoor) and those occurring in the detritus which covers large areas of bottom land in the border valleys of the Moor.
The Occurrence of Colloid Silica in the Lower Chalk of Berkshire and Wiltshire
Authors: Jukes-Browne A. J. , Hill W.
Published: October 2009

The existence in the Lower Chalk of beds containing a certain proportion of pure disseminated silica is not a new discovery, the occurrence of such material having been proved by Messrs. Way and Paine in 1851; but we are not aware that it has ever before been found in such quantity, or that any detailed investigation of its mode of occurrence has previously been made.

The beds which are the subject of the present communication were discovered during the examination of the Lower Chalk of Berkshire and Wiltshire in 1887–88, for the purposes of the Geological Survey, and we are indebted to the Director-General of the Survey for permission to make use of the stratigraphical information then obtained. Beds of siliceous chalk were first observed near Wantage and Letcombe Bassett, and attracted attention from their hard and compact character; they occurred near the horizon at which the Totternhoe Stone is found further north, and it was at first thought possible that one of them might be the representative of that stone. Specimens were therefore submitted to microscopical examination, and were found to be different from Totternhoe Stone and from any other samples of Lower Chalk previously examined by us. The exact stratigraphical position of these beds was subsequently ascertained by means of the excellent section exposed by the cutting on the Didcot, Newbury, and Winchester line, near Chilton.
On certain Chelonian Remains from the Wealden and Purbeck
Authors: Lydekker R.
Published: October 2009

a.
Plastron from the Wealden
.

Certain fragments of the plastron of a Chelonian collected by the late Dr. Mantell from the Wealden of Sussex, and now preserved in the British Museum, are of some interest as affording evidence of the presence of an additional series of epidermal shields unknown in any previously described form, and probably indicating an extremely archaic type of structure.

The first specimen that may be noticed is the imperfect left xiphiplastral, to which is suturally united a portion of the hypoplastral, this bone (No. 3506) being represented in fig. 1. It appears probable that the proximal portion of the bone is broken away, and that the hypoplastral element was originally extended upwards to form the inguinal portion of the bridge for connexion with the carapace. The peculiar features connected with this specimen are, however, the sulci left by the epidermal shields. It will be seen from the figure that on the outer border there are two narrow shields (
an., fem.
which from their relation to the xiphiplastral suture I take to represent the anal and femoral shields of the normal type. Above the femoral is seen the commencement od a third lateral shield, which may be correlated with the abdominal. On the inner side of these lateral shields are portions of two larger shields, which may be termed interfemoral and interabdominal. There are no means of determining whether these inner shields were azygous or paired, although I am inclined to think that they were probably azygous.
The Upper Jurassic Clays of Lincolnshire
Authors: Roberts Thomas
Published: October 2009

The broad tract of low country which extends from the Humber through the middle portion of Lincolnshire, and spreads out into the fen-country to the south, is underlain by a thick deposit of clay which, in the adjoining county of Cambridgeshire, has been called the “Great Fen-Clay“
*
. The lower portion of this great pelolithic formation is undoubtedly of Oxford-Clay age, whilst its upper portion certainly belongs to the Kimeridge Clay. Owing to the absence of beds lithologically resembling those of the Corallian rocks of Yorkshire and the southern and south midland counties of England, no division corresponding in age to the Corallian has as yet been made out in Lincolnshire.

Prof. Blake states that the Kimeridge and Oxford Clays here form one continuous formation †. In the Survey Memoir on this district it is mentioned ‡ that the Corallian group is entirely absent, and only the Oxford and Kimeridge Clays are mapped. Jukes-Browne goes still further, and states that “in Lincolnshire there is nothing to represent the Corallian group, the Oxford Clay merging gradually into the Kimeridge Clay“§. H. B. Woodward mentions that in Lincolnshire, Buckinghamshire, Norfolk, and probably Sussex, “the Kimmeridge and Oxford Clays come in direct sequence,“ and he adds that“ unless we imagine an unconformity— and there is no reason for this supposition—the Coral Rag and Calcareous Grit developed in Oxfordshire, Wiltshire, and Dorsetshire, are represented by portions of the Oxford and Kimmeridge Clays in the districts just mentioned“║. No attempt, however, has as yet been made to separate off a portion which would be equivalent to the Corallian of other areas.

3.

Kimeridge Clay
:—

(
b
)

Upper Kimeridge: thin papery shales, with
Discina latissima
.

(
a
)

Lower Kimeridge: dark clays, with septarian nodules, subdivided into:—

(iii.)

Clays with
Amm. mutabilis, Astarte supracorallina
, &c.

(ii.)

Clays with
Amm. alternans
.

(i.)

Clays crowded with
Ostrea deltoidea
.

2.

Corallian
. Black selenitiferous clays, with
Amm. plicatilis, Amm. cawtonensis, Bel. abbreviatus, Gryphæa dilatata, Ostrea deltoidea
, &c.

1.

Oxford Clay
, subdivided into five palæontological zones, with the Kellaways Rock at its base.
Descriptions of some New Species of Carboniferous Gasteropoda
Authors: Donald
Published: October 2009

With one exception the Gasteropoda described in this paper have been collected by Mr. John Young, Hunterian Museum, Glasgow. The specimens are all very minute and are well preserved, their creamy colour giving them the appearance of shells of a much more recent date than the Carboniferous period. With the best of materials, however, the affinities of the Palæozoic Gasteropoda are always more or less difficult to determine. In this instance though the sculpture of the surface is wonderfully well preserved, none of the apertures are entire, and the minute size of the shells renders it difficult in many instances to discern the lines of growth. Out of the five Scottish shells three are undoubtedly Murchisoniæ, one in particular having the band indicating the sinus in the outer lip very clearly defined.

With regard to the other two shells, I know of no genus to which they may be referred, unless it be
Orthonema
, Meek and Worthen. The more elongated shell bears some resemblance to species of the genus
Aclisina
, de Koninck, from which it differs, however, in the form of the mouth and the flattened, closely coiled whorls.
On Tachylyte from Victoria Park, Whiteinch, near Glasgow
Authors: Rutley Frank
Published: October 2009

In a paper published last year in the ‘Transactions of the Geological Society of Glasgow' by Messrs. John Young, F.G.S., and D. Corse Glen, F.G.S., an interesting account is given of certain intrusive sheets and veins of dolerite passing through Carboniferous shales and sandstones, which contain the erect stems of fossil trees, determined by Mr. R. Kidston, F.G.S., as those of
Lepidodendron Veltheimianum
. In one instance a thin vein of the dolerite was found to pass completely through one of the trees a little above the roots. There can therefore be no doubt that these dolerite veins were formed, as the authors point out, subsequently to the growth of the trees and the deposition of the surrounding beds.

In the paper already cited the authors duly recognize the tachylytic character which the margins of the smaller intrusive veins present in the following words:—

“In this quarry we have the interesting evidence that along these lines, especially in the thinner veins, the dolerite has cooled as a vitreous glassy lava, in which a thin layer, showing micro-spherulitic structure, has been developed during the process along the surface of both faces of the vein. These veins are now seen to have lost their glassy structure through devitrification, and are of a whitish colour, but their spherulitic structure, which still remains, clearly indicates that they once existed as veins of a glassy tachylyte. This is the first instance in which we have found such a structure amongst the dolerites of the Glasgow Coal-field.”
Notes on the Bagshot Beds and their Stratigraphy
Authors: Lyons H. G.
Published: October 2009

Since the publication in the Quarterly Journal of the Society (Q. J. G. S. xliii. p. 431) of a paper on the London Clay and Bagshot Beds of Aldershot, I have made a number of observations on these beds as they occur in the area between Aldershot and Ascot. These observations I would now place at the disposal of other workers, as I shall have no further opportunities of making use of them, and I would also shortly refer to the results to which they seem to me to lead.

In my previous paper, referred to above, I only discussed the beds at their southern outcrop over an area about 5 miles from E. to W. by 2 miles from N. to S., and showed that within this area the Bagshot and London-Clay strata remained of constant thickness and dipped at an angle of about 2¼° northwards.

Over so small an area it was easy to obtain sections which would show what was required, and at the same time of a length short enough to avoid the necessity of any great exaggeration of the vertical scale in order to show the details.