The study of the nature and causes of the phenomena of volcanic activity, which for some time previously seemed to have almost fallen into abeyance, has during the last few years attracted the attention of many patient observers and earnest thinkers. In proof of this statement, we need only point to the valuable essays upon the subject which have recently been published by Dana, James Hall, Le Conte, Shaler, Hilgard, Sterry Hunt, and others in America, and to those by Mr. Mallet, Captain Hutton, the Rev. O. Fisher, and others in this country.

It is now fifteen years since the appearance of the second edition of the late Professor Jukes's memoir on the Geology of the South Staffordshire Coal-field. The author observed in his preface that a revision of his work had been rendered necessary by the opening of many new mines and cuttings of various kinds which had afforded fresh information on points that had previously been obscure. He mentioned, for instance, certain red clays and sandstones occurring at Walsall Wood, and at other places which were at first supposed to belong to the New Red Sandstone, afterwards believed to be Permian, but were ultimately decided to be Coal-measures.

The two substances known as “Tasmanite” and Australian “White Coal,” which are the subject of the present communication, have a special interest for the geologist on account of the light which they throw upon the microscopio structure and composition of many Coals. My attention was first directed to them when collecting materials for Professor Huxley’s examination into the microscopic structure of Coal. My esteemed colleague, Mr. Etheridge, at that time gave me a specimen of brown laminated substance, labelled “Lignite, the so-called White Coal, Australia,” and drew my attention to the fact that it was very largely composed of small seed-like bodies, very similar to, although smaller than, the macrospores of Flemingites, which are to be seen in many kinds of British Coal. A specimen of this same kind of White Coal is in the Museum of Practical Geology, and is labelled, “ Bituminous Shale (locally called White Coal), New South Wales, Australia.” I have likewise been able to examine the specimen of Tasmanite also in this Museum, which is labelled “ Tasmanite; combustible matter from the river Mersey on the north side of Tasmania; stratum of unknown thickness, but known to extend for some miles. Presented by Sir Won. Denison.” These specimens are very similar in appearance and structure, but the White Coal is softer than the Tasmanite. Chemical analyses of Tasmanite have been published, but I am not aware of any satisfactory account of ’its microscopic structure. The only mention of Australian White Coal with which I am acquainted is that in Prof. Huxley’s lecture on “On the Formation of Coal” (“Contemporary Keview,” Nov. 1870). And there is a figure, of a section and some separated spores, given by Sir C Lyell in the 2nd edition of his Student’s Elements of Geology, 1874.

The fossils, which will be described hereafter by Dr. Günther, F.R.S., Prof. T. Rupert Jones, F.R.S., H. Woodward, F.R.S., and H. B. Brady, F.R.S., were found in the years 1873 and 1874 partly in rocks of the “Padangsche Bovenlanden” (Highlands of Padang), Government of the West Coast of Sumatra, and partly in marls and limestones of the Island of Nias.

During the earliest periods concerning which we have historical records in Southern Europe, Vesuvius was certainly inactive, its true character, indeed, long remaining wholly unsuspected; nor do the eruptions of Etna at this epoch appear to have been of such a character as to have powerfully arrested the attention and excited the imaginations of the oldest inhabitants of the district. Far otherwise was it, however, with the volcanos of the Lipari Islands; in these the manifestations of igneous activity had been so constant and striking, that priests, poets, and philosophers had successively associated the locality with their most marvellous stories.

Presenting as it does the only example of a volcano in the phase of permanent moderate activity to be found in Europe, Stromboli must always have the strongest claims on the attention of geologists. Here may at all times be witnessed, in perfect security, those explosions produced by the disengagement of vapour in the midst of masses of liquefied rock, which, following one another at longer or shorter intervals, and taking place with greater or less violence, constitute a most striking feature in nearly all volcanic eruptions; and the causes, sequence and attendant phenomena of these outbursts can in the case of this volcano be most conveniently studied.

Leopold von buch, who in the beginning of this century travelled through Norway as far as the North Cape, was the first who wrote about the geology of the northern part of the country (Reise durch Norwegen und Lapland, Berlin, 1810). Some years later the natural conditions of the country were examined by Vargas Bedemar. On this voyage he went as far as Varanger, and has recorded the result of his inquiries in his work “Reise nach dem hohen Norden, Frankfurth-a.-Main, 1819.” Furthermore R. Everest, who travelled through Norway to the North Cape in the years, between 1825 and 1830, has collected various notices on the mountain structure of the countries in his work entitled “Journey through Norway.”

The following species of Modiola is common to the Carboniferous Limestone series of England and Scotland, and appears to have been hitherto undescribed from them, although it may, perhaps, be identical with an American Sub-carboniferous species.

Only a few years ago it was looked upon as an article of faith among geologists, that the whole globe was once in a melted incandescent state, and that the conditions of temperature now prevailing on the surface of the earth have been in process of time produced by the slow gradual cooling of the once fused and glowing mass. It then appeared so natural that, in consequence of the earth’s internal heat, a tropical climate should extend from pole to pole, that no special weight was attached to the evidences of this fact which geology was at that time able to produce. The Dane Giesecke’s and the English Scoresby’s specimens of fossil plants from the east and west coasts of Greenland, evidencing a warm climate there, attracted so little attention, that neither they, nor the fossil remains of Saurians found by the famous Arctic traveller Sir Edward Belcher in the American Polar Archipelago, could be found in the museums to which they had been confided.

Iceland—that land of Frost and Fire, an island which, though as X large as Ireland, is, apparently, but a crust of hardened lava over a seething cauldron of the same substance, bearing on its frozen surface eternal snows and glaciers—has been this year in extraordinary commotion, socially and politically, as well as physically. It has celebrated the millenary of its colonization, and for the first time in this long period received a visit from its sovereign; while it has been so devastated of late by frequent fiery eruptions, the ashes from which destroy its pasturage—the only resource of the islanders—as to have driven them, it is said, to the desperate resolve to emigrate en masse, and leave their native land for a safer, at least, if not a more genial residence, in the far North-West of the American Continent.

It is a fact universally accepted that, within a period comparatively recent, extensive districts in North America and in Europe, now fruitful and luxuriant, were covered with a thick mantle of snow and ice; and their valleys were filled with glaciers, which extended into the sea, and, breaking off at their extremities, floated away as icebergs.

In this paper I purpose giving a history and description of the Cretaceous group of Aporrhaïs, as far as they are at present known to me, especially of those forms which are so beautifully preserved in the Gault of Folkestone, and so-called Upper Greensand of Blackdown. I regret that I cannot include the Aptien and Neocomien species, but the collections at present open to me are too meagre to give anything like a complete account of them. In the whole group there are even now many points which require further research; the correlation of some of the forms with those on the Continent is still unsatisfactory, from the difficulty experienced in comparing actual specimens. The figures available, even in the most modern works, appear in some cases to have been restored, and not therefore to represent the form of any shell that has been really met with.

Amongst the parallelisms which may be drawn between the Silurian series of Britain and that of North America, none so far has been so certainly established as the equivalency of the “Niagara Formation” to the Wenlock Group. In its most typical development, as in the State of New York, the Niagara formation, consists of an inferior series of argillaceous sediments, the “Niagara Shales,” and of a superior series of calcareous accumulations, the “Niagara Limestone.” At the Falls of Niagara itself, and at the Falls of the Genesee at Rochester, the shales and limestones are about eighty feet in thickness each. In Pennsylvania, the Niagara formation is wholly shaly, and has a thickness of over fifteen hundred feet. In the States west of New York, again, the formation is almost wholly calcareous, many of its members being true dolomites, and its total thickness rarely reaches three hundred feet, and is usually much less. In Western Canada, finally, the Niagara shales can rarely be detected as a distinct group, and the formation consists mainly of limestones, often magnesian, with subordinate courses of shale, the whole usually varying from one hundred to two hundred feet in thickness.

Perhaps no district of equal area could be named in which so many instructive illustrations of volcanic action may be witnessed as the beautiful island of Ischia. Although only about six miles long by four broad, yet this island exhibits a great central volcanic mountain,—named “Epomeo”—surrounded by numerous parasitical cones and craters, which, alike in their features and their products, present the most interesting variations.

In my paper on Glacial Erosion lately laid before the readers of the Geol. Mag. (pp. 323 and 356), I have endeavoured to prove that the origin of nearly all the more prominent surface characteristics of the rock scenery in the Yorkshire Dale District admits of a simple and complete explanation by the theory of the modification of pre-existing subaerially eroded surfaces by Glacial Erosion. At the same time it was shown that the character of many of the phenomena is entirely opposed to any theory of their origin by means of Subaerial Denudation alone. In the present communication it is proposed to inquire how far this Glacial Erosion theory may be applied to explain the origin of the deep, semicircular recesses that are commonly found in all well-glaciated mountainous districts, and are variously known by the names of Coums, Corries, or Cirques.

Tschermak examined two microscopic sections of the Ovifak rocks, and compared them with sections of the meteorites of Jonsac, Juvinas, Petersburg, and Stannern, which consist chiefly of augite and anorthite, with little or no nickel-iron; they form a class which G. Rose termed ‘eucritic.’ Both sections exhibit a crust, as meteorites possess; it is, however, so altered by oxidation, that it is not possible to determine whether it is the fused crust usually noticed on a meteorite. The crystals of felspar, which, according to Nauckhoff's analyses, must be regarded as anorthite, are fully developed; they penetrate the augite, iron, and magnetite, and must evidently have been formed before them. They are completely transparent, and have but few and large cavities, which are filled, partly with black granules, partly with a brown substance of irregular form; some traversing the length of the crystals are filled with a transparent glassy substance. The augite is of a light greenish-brown hue, traversed here and there by flaws; it fills gaps between the other constituents, as has been often observed in dolerites and diabases, and encloses individual black grains. In the section containing iron the colourless felspar encloses a black or brown substance running the length of the crystals, or dust-like fine black granules, or larger round transparent bodies of a violet colour, which may be the mineral Nauckhoff regards as spinel.

Shell elongated, spire composed of many convex whorls, which are very finely striated, 2 or 3 of the striæ being very distinct and wide apart in front of the sutures. The last 2 whorls have 10 or 11 and the other whorls have 14 or 16 well-marked ribs, with occasional varices. On the last whorl there is a slight angularity in place of keel. The wing exactly resembles that of A. Parkinsoni, and in this may be distinguished from that of A. Mantelli. The anterior canal is moderately long.

Group 4.—Spire moderately long, generally without carinæ, always ribbed transversely. Wing expanded and quadrate, prolonged posteriorly into a sharp point.

The interesting story of the discovery of these enormous masses by Prof. Nordenskjöld is already known to the readers of this Magazine through a translation of his original memoir. While exploring in Danish Greenland in 1870, his attention was directed to the possibility that meteorites might be met with in Disko Island, by the accidental discovery of a block of meteoric iron in some ballast which had been taken in at the old whaling-station at Fortuna Bay, near Godhavn, and he urged the Greenlanders to search the district for masses of that metal.

Note.–The Fossils about to be described were sent to England in 1873 and 1874 by Heer R. D. M. Verbeek, Director of the Geological Survey of Sumatra, and are here published by the authority and with the aid of the Dutch-Indian Government.