case as regarded the absence of coal in the eastern and portions of the midland counties, now overspread by Mesozoic formations. The author proceeded to show that there was evidence that the coal-measures were originally deposited in two continuous sheets, one to the north and the other to the south of a ridge of old land, formed of Silurian rocks, which stretched eastward from Shropshire, and ranged along the south of the Dudley coal-field. This dividing ridge, or barrier, had probably never been altogether submerged beneath the waters in which the coal-measures were deposited. Referring to the tract of coal-measures which lay to the north of the central barrier, it was shown that towards the north the boundaries of the coal-formation were formed by the Cambro-Silurian rocks of North Wales, the Lake-district, and portions of the "southern uplands" of Scotland. The southern limits were formed by the barrier of old land, and over this intervening area the coal-measures were spread in one continuous sheet, and attained their greatest vertical dimensions towards the north-west. To the south of the barrier, the strata were deposited in the greatest thickness towards the west or south-west.

At the close of the coal-period, disturbances of strata (resulting probably from lateral pressure acting from the north and south) took place over the whole Carboniferous area of the north of England, whereby the strata were thrown into a series of folds, the axes of which ranged along approximately east and west lines. These disturbances were accompanied and followed by enormous denudations, by which the coal-measures were swept away over large tracts of the north of England, and the northern limits of the Lancashire and Yorkshire coal-fields were approximately determined.

Referring to the tract south of the central barrier, Professor Hull expressed his opinion that the east and west flexures, being parallel to those of the north of England, were referable to the same geological period, namely, post-Carboniferous (or pre-Permian). At this period the northern and southern limits of the South Wales coal-field, the axis of the Mendip Hills, and the easterly trend of the culmmeasures of Devonshire were determined. Denudation of strata on an enormous scale accompanied these movements. After the deposition of the Permian beds over the inclined and denuded edges of the Carboniferous rocks, disturbances accompanied by extensive denudation took place along lines nearly at right angles to those of the preceding period; that is, along north and south lines approximately. To this epoch, the axis of the Pennine chain and all north and south trendings of the strata were to be referred. Some of the results brought about by these movements were the disseverance of the Lancashire and Cheshire from the Yorkshire and Derbyshire coal-fields, the determination of the western limits of the Flintshire and Derbyshire coal-fields, the disseverance of the Forest of Dean coal-field from that of South Wales, and the uptilting of the Lower Carboniferous rocks along the eastern margin of the Somersetshire coal-field, beneath the Jurassic formations. From these considerations it seemed clear to the author that the basin-shaped form of nearly all the coal-fields (the basins being sometimes partially concealed by the Mesozoic rocks) was due to the denudations acting over areas of elevation intersecting each other nearly at right angles, and corresponding to two distinct epochs-the pre-Permian and pre-Triassic. Professor Hull then proceeded to show that over these Carboniferous basins the Permian and Triassic rocks were distributed according to a well-defined plan of south-easterly attenuation, or thinning away towards the south-east; and he concluded by discussing the views of Sir R. I. Murchison, Professor Ramsay, and Mr. Godwin-Austen, regarding the existence or absence of coal under the Cretaceous or Tertiary strata of the south of England.

On the Red and Coralline Crags. By CHARLES JECKS.

The author suggested the following reasons, as rendering it probable that the Red and Coralline are quite as nearly connected with each other as the Red and Norwich Crags. If the paleontological difference between the Red and Norwich Crags be about 20 per cent., and yet be considered synonymous, how is it that the Coralline Crag, which only contains 10 per cent. fewer recent species than the Red,

should be held as distinct from it? When we find that 103 shells are common to the Red and Coralline Crags which are not found in the Norwich Crag, whilst only two are common to the Red and Norwich Crags, and are not found in the Coralline, surely such a fact directly implies not only a connexion, but one almost as close between the Coralline and Red as the Red and Norwich Crags. There seems, indeed, every reason to believe that the transition from the Coralline to the Red Crag was gradual; if there were now to be an elevation of sea-bottoni, including what we call the Coralline and Laminarian zones, the former would naturally become Laminarian, while the latter would become a Littoral zone, and this in all probability without any really sudden change in species, but by a slow process of elevation; nay, is there any sudden change now observable in the species inhabiting these zones? do they not gradually commingle ? and if this be so as regards the Coralline and Laminarian zones of the present time, is it not quite as likely to have been so with regard to the Coralline and Red Crags?

Sir C. Lyell, in his sixth edition of the Elements,' seems distinctly to favour the idea of the unity of the Crag, in the following extract:-"The shells of the Crag exhibit clear evidence of a gradual refrigeration of climate, which went on in the area of England from the time of the older to that of the most modern Pliocene strata."

With regard to the objection, that the denudation of the Coralline, as evinced by the unconformability of deposition of certain parts of the Red Crag, shows a certain break, as it were, in the continuity of the deposit, would it not be obviated, in some measure at least, by the fact of there having been many changes in the conditions of life in the Coralline Crag species owing perhaps to the intrusion of other species and consequent disturbance in their mutual relations, so that in course of time they would die out, together with a gradual, long continued, but decided change in climatal conditions? Upon the whole, then, it seems probable that the period from the commencement to the end of the Pliocene is one of gradual transition, of which the Coralline, Red, and Norwich Crags represent so many stages, not distinct and separate, but more or less connected together by various changes in the relations of one organism to another, caused by variation of species under natural selection, and also by changes in climatal conditions and nature of sea-bottom.

Remarks on Newer Tertiary Fossils in Sicily and Calabria.
By J. GWYN JEFFREYS, F.R.S.

During the last deep-sea exploring expedition in H.M.S. 'Porcupine,' in the Bay of Biscay and along the Atlantic coasts of Spain and Portugal, Mr. Jeffreys procured at considerable depths, and especially from 994 fathoms, many species of Mollusca in a living or recent state, some of which had been previously regarded as fossil only, and extinct, and all of them belonging to the newer tertiaries of Sicily and Calabria; and he believed that a record of the fact might lead to the discovery of the geological phenomena which had caused the fossilization of such species in that limited area. Several of these species inhabit northern and even arctic seas; and among them are Terebratula cranium, T. septata, Pecten aratus, P. vitreus, Lima excavata, Mytilus vitreus, Leda frigida, Limopsis aurita, L. borealis, Dentalium abyssorum, Puncturella noachina, Hela tenella, and Pleurotoma carinata. Other species now found in a living or recent state are Terebratula sphenoïdea, Tellina compressa, Verticordia acutecostata, V. granulata (the last two being Japanese), two species of Fissurisepta, Trochus suturalis, Turbo filosus, Omphalus monocingulatus, Scalaria pumila, Cyclostoma delicatum of Philippi (Reclusia ?), and Pleurotoma hispidula. One of the species in the second list or category (Fissurisepta papillosa) had been also dredged by Mr. Jeffreys last autumn at Dröbak, in Norway; and he was of opinion that our knowledge of the arctic marine invertebrate fauna was very imperfect. The newer Tertiary fossils of Sicily and Calabria had been to a great extent investigated by Dr. Philippi formerly of Čassel, Prof. Seguenza of Messina, the Abbé Brugnone of Palermo, and Dr. Tiberi of Resina near Naples; and their collections had been examined by Mr. Jeffreys. Two suggestions or questions were submitted by the author of the present paper,

viz.:-1st. Have not all the deep-sea species of European Mollusca originated in the north, and spread southwards in consequence of the great arctic current? 2nd. Inasmuch as the Pliocene division of the Tertiary formation is now ascertained to contain scarcely any extinct species, and future explorations may reduce the percentage of such species to nil, may not that artificial division hereafter merge in the quaternary formation, and the Tertiaries be restricted to Eocene, Miocene, and Oligocene ?

On the Age of the Wealden.

By JOHN W. JUDD, F.G.S., of the Geological Survey of England and Wales. Unconformities between formations indicate, as Mr. Darwin, Prof. Ramsay, and other geologists have argued, the lapse of enormous periods of time. Between the Oolitic system, terminating with the Portlandian, and the true Cretaceous, commencing with the Gault, there is not only an immense physical break, but a total change in species. The researches of continental geologists have shown that, intercalated between these two systems, there exists two others, each in every way worthy to rank with them, the Tithonian and the Neocomian; these do not, however, entirely bridge over the interval, for the Cretaceous is almost everywhere unconformable to the Neocomian.

The English Wealden consists of a mass of freshwater strata, probably not less than 2000 feet thick. Forming its lower and upper members, however, are certain fluviomarine strata, which form passages into the marine beds below and above the Wealden. The lowest of these fluviomarine or passage series is the wellknown Purbeck formation, the marine beds of which contain Oolitic fossils. In the Isle of Purbeck, the Isle of Wight, and elsewhere is found another series of strata, less known, but not less important, which indicates the gradual passage upward of the Wealden into the Upper Neocomian (Lower Greensand).

Of especial interest, from the large fauna which it yields, is the marine band of Punfield, to which the attention of geologists was first directed by Mr. GodwinAusten in the year 1850. This bed is only 21 inches thick, and is situated 140 feet below the top of the Wealden; the author has found that it contains a series of fossils (including many species and one genus quite new to this country) identical with those of the coal-bearing strata of Middle Neocomian age in Eastern Spain, which are more than 1600 feet thick.

The Wealden presents every appearance of being a single continuous formation. In its lower portion it contains marine beds with oolitic fossils, and graduates into the Portlandian; in its upper part it contains other marine beds with Middle Neocomian fossils, and graduates into the Upper Neocomian. We are thus led to the conclusion that the great epoch of the Wealden commenced towards the close of the Oolitic period, that it continued through the whole of the Tithonian and the Lower and Middle Neocomian, and only came to an end at the beginning of the Upper Neocomian.

In confirmation of these views as to the age of the Wealden, there exists much palæontological evidence. Still further support is afforded to them by the manner in which Wealden and Neocomian beds are found alternating with one another in France, especially in the Pays de Bray and in the district of Champagne.

Professor Huxley has indicated the necessity of establishing a distinct classification for freshwater and terrestrial formations, the breaks between which do not correspond with those of the marine series. Of this necessity the Wealden, representing, like the "Poikilitic," several very distinct marine formations, is a very striking illustration.

The author has before shown that the deposition of the Wealden strata of Northern Germany commenced at the close of the Oolitic period, and had terminated before the end of the Lower Neocomian. He concludes therefore that the English and German Wealdens are not strictly contemporaneous, and that, the areas being quite disconnected, they are probably the products of two different rivers.

On some Points in the Geology of Strath, Isle of Skye.

By Professors KING and RowNEY.

The authors entered into a minute description of a section of the east shore of Loch Slappin. The rocks consist of syenite, overlaid by serpentinous marble or ophite, and a number of unaltered stratified deposits following in consecutive order. An unbroken passage was traced from the marble to the highest beds; the latter are more or less charged with Liassic fossils. The following conclusions were come to by the authors:-(1) That the ophite of Strath is an altered rock of the Liassic period, as long ago maintained by Macculloch and Geikie; (2) that it possesses the same microscopic features as those, supposed by some to be of organic origin, which occur in a corresponding rock of earlier geological ages, known in Canada, Connemarra, and elsewhere; (3) that igneous action, developing a granitic rock, and producing decided metamorphism in an adjacent deposit, has operated at a later geological period in Skye than in any other part of the British islands. Referring to their published memoirs in the Quart. Journ. Geol. Soc.' vol. xxii. 1866, and the 'Proc. Roy. Irish Acad.' vol. x. 1870, in which certain of the above microscopic features in the Skye ophite were first made known, the authors in the present paper announced their discovery of some others, which completely identify this comparatively modern rock with the "eozoonal" marble of Canada, belonging to the Laurentian system; and they maintained that the repeated occurrence, so often pointed out by them, of "chamber casts" (grains of serpentine, &c.), "canal system" (metaxite, &c.), and "nummuline layer" (chrysotile), in metamorphic or crystalline rocks only, proves in the simplest manner the purely mineral origin of the so-called "Eozoon Canadense." Sections and numerous specimens, including a large block of the Skye "eozoonal" marble, were exhibited.

On the Discovery of Upper Silurian Rocks in Roxburgh and Dumfriesshire. By CHARLES LAPWORTH.

On the Tertiary Coal-field of Southern Chile.

By G. A. LEBOUR, F.G.S. &c., and W. MUNDLE, M.E.

The coal-formation of Chile occupies a marginal position along the western coast of South America, extending from Talcahuano near Concession on the north, to the Straits of Magellan on the south. It rests unconformably upon mica-schists and other metamorphic rocks, which form the main geological feature of the country. The coals are for the most part of an inferior description, mere lignites in fact. The accompanying rocks are alternating sandstones (grey, white, and yellow), shales and indurated clays, true underclays, and occasional bands of calcareous matter. A detailed typical section of the strata at Coronel was given by the authors.

The fossils of these beds belong, some of them, to what in Europe would be undoubted secondary age; for various reasons, which he will defer to another paper, Mr. G. A. Lebour believes with Darwin that they indicate more probably a very early Tertiary age.

The other portions of the paper referring to the mode of deposition &c. of the beds in question cannot be written in short without the aid of figures.

On the Stratigraphical Distribution of the British Fossil Gasteropoda. By J. L. LOBLEY, F.G.S.

On the Silurian Formations of the Centre of Belgium.
By Professor CONSTANTINE MALAISE (of Gembloux).

M. Malaise pointed out that the terrain ardoisier of D'Omalius d'Halloy (the Ardennais and Rhénan formations of Dumont) are the representatives of the Cambrian, Silurian, and Devonian rocks of England. He has attempted to establish the analogues in Belgium, where at first the references to English types were in

correct.

The Belgian formations regarded as Silurian and Cambrian are found in the Ardennes in Brabant, parallel to the Meuse and Sambre, and near Dour in Hainault. The Silurian or Cambrian of the Ardennes rests unconformably on the Devonian. The ill-preserved fossils that have been found do not sufficiently determine the age, consisting only at present of Dictyonema and part of a Trilobite belonging to the genus Paradoxides, which would place it in the Cambrian. The true Belgian Silurians] belong to part of the Rhénan series of Dumont, in which Silurian fossils were found in 1860 by M. Gosselet.

The Brabant Silurian deposits extend over an area about 70 miles long, the greatest width being 16 miles. That of the Sambre and the Meuse is a strip about 40 miles long, and less than two miles wide.

The Brabant series is divided into four groups, the upper alone of which has yielded fossils, and this alone is represented in the Sambre and Meuse district. The following are the groups in descending order :

:

1. Gembloux series (quartziferous schists).

2. Oisquezcq series (variegated and graphitic schists).

3. Tubise series (quartzites).

4. Blaumont (lower quartzites).

From the upper series 52 species have been obtained, several of which appear new; they include Trilobites, Brachiopoda, and Graptolites, characteristic of the upper members of the Lower Silurian, a second stage of M. Barrande, mixed with some Upper Silurian species.

Synchronism and Foreign Equivalents. With regard to the analogies of the Belgian Silurians with those of other countries, the author agrees with M. Barrande that his second stage, represented in the Bohemian district by quartzite, and also represented in almost all Silurian districts, occurs in its ordinary state in Belgium. In England it includes the Llandeilo and overlying Caradoc groups, and in Ireland the recognized equivalents, while in France, Spain, Portugal, Thuringia, Sweden, Norway, Russia, and North America it is known by various names. It is represented in Belgium by the genera Illanus, Trinucleus, Ampyx, and others.

Species have also been found referred to Dalmanites, Cheirurus, Lichas, Calymenes, Acidaspis, Homalonotus, but to groups peculiar to the second stage. The great development of Orthis common in England, Russia, and the United States is also remarkable in Belgium. Cystidea have also been met with.

On the Formation of Swallow-holes or Pits with Vertical Sides in Mountain Limestone*. By L. C. MIALL.

The paper described two kinds of these cavities, one designated "cavities of erosion," and the other "cavities of subsidence." A detailed account was given of a singular excavation at the head of Swaledale, typical of the first species. Its peculiarities were defined as consisting of vertical, fluted sides, and isolated pillars in the centre of the pits. Falling water, aided by pebbles, was looked upon as the source of excavation, and a thick surface-covering of drift, retentive of moisture, was regarded as an essential feature, the spongy mass discharging the rainfall at certain regular points. Those swallow-holes were next considered whose existence is due to subsidence of an undermined crust; and many examples were cited and discussed, principally from the mountain-limestone district of Craven. The effects of such subsidences upon superficial deposits (as of glacial drift) were adverted to in conclusion.

On the Evidences of Recent Changes of Level on the Mediterranean Coast+. By GEORGE MAW, F.G.S., F.L.S., &c.

The author in this paper pointed out, from personal observation, the various evidences the Mediterranean coast presents of changes of level, both above and below the existing shore-line.

* This paper is printed at length in the 'Geological Magazine' for November 1870. + Printed in extenso in the 'Geological Magazine' for December 1870.