Remains of birds are among the rarest of fossils, and few have been described save from the more recent formations. With the exception of Archœopteryx from the Jurassic, and a single species from the Cretaceous, no birds are known in the old world below the Tertiary. In this country, numerous remains of birds have been found in the Cretaceous, but there is no satisfactory evidence of their existence in any older formation, the three-toed footprints of the Triassic being probably all made by Dinosaurian reptiles.

The study of the great mountain ranges of America by Rogers, Hall, Dana, Le Conte, Hunt, and other geologists, has now thrown much new light on the earth-movements which precede and accompany the formation of mountain chains. As the result of these researches, it appears certain that the preliminary stage in the formation of every mountain system has consisted in a long-continued depression of the area which is afterwards to become its site; and, in consequence of this prolonged subsidence, the accumulation of an enormous thickness of stratified rocks, within the great trough so formed, has taken place. Of this character, as is now well known, have been the earlier manifestations of the subterranean forces that were concerned in the formation of the Appalachians, Green Mountains, and other American ranges; the districts in which they are situated were subjected to long-continued depression, which permitted of an abnormal development of all the members of the sedimentary deposits formed during this initiatory period; and it was by the folding, metamorphism and crushing together of this abnormally thickened portion of the earth's crust that the indurated and elevated masses have been formed which denudation has sculptured into the existing mountain chains.

The Geological Magazine for October, 1875 (pp. 477–486), contains an article “On the Geology of Central Sumatra,” by Herr R. D. M. Verbeek, Superintendent of the Geological Survey of that island, in which the position of the fossiliferous rocks of the Highlands of Padang is sketched in a manner as clear as concise, and which must be consulted by those who desire to understand the palæontological age of the fossils described in this paper.

The celebrated statuary marbles of Carrara, which have of late I years been universally described as of Jurassic age, have quite recently been shown conclusively to belong to the Carboniferous series, and the steps which have led to the discovery form an instructive illustration of the difficulties which beset Alpine Geology. No one has a better right to relate the history of the classification of the rocks of the Apuan Alps than M. Coquand, and this he is now doing in a series of papers published in the Bulletin of the Geological Society of France. From the first of these we arrive at the following résumé of the various opinions which have been held-from time to time regarding the age of the statuary marbles.

Of the amount of vertical movement which took place in the great mountain axis of the Eastern continent, subsequently to the deposition of the Eocene strata, the following facts afford sufficient proof. The marine Nummulitic rocks, besides constituting very large portions of the flanks of this vast mountain axis, and of its connected chains, such as the Pyrenees, the Carpathians, and the Caucasus, form the actual summits of such grand Alpine peaks as the Diablerets, and the Dent du Midi, rising to the heights of 10,670 and 10,531 respectively above the sea-level; while in Western Thibet the same Eocene strata are seen raised to an elevation of no less than 16,500 feet above the sea.

In a paper on “The Physical Conditions under which the Cambrian and Lower Silurian Rocks were probably deposited over the European Area,” Mr. Hicks has recently put forth some opinions on the lowest fossiliferous rocks of Scandinavia and Russia, and their relations, as to age and stratigraphical characters, to those of Britain, which I think ought to be somewhat modified. The chief assertions in Mr. Hicks's paper are, that at the Pre-Cambrian period a large continent existed in Europe; that a subsidence began in the south-western part, and gradually extended to the north-eastern, which was not submerged until the Tremadoc group had been deposited over the western areas; and, finally, that the marine faunas migrated from the south-west. In order to prove these generalizations, Mr. Hicks makes a comparison between the most important Cambrian districts of Europe. He thinks that the British Cambrian rocks are the oldest, that the lowest Swedish beds are probably equivalent to the British Menevian group, and that the Russian are not older than the Arenig. Though the scantiness of the organic remains in some instances makes it very difficult, or, indeed, impossible to parallelize with certainty the oldest deposits of the various countries, it seems, however, from the palæontological facts already known, quite unquestionable that the lowest rocks of Scandinavia and Russia are older than Mr. Hicks has supposed them to be in comparison to those of Britain.

My friend and colleague, Mr. Goodchild, has contributed to the Geol. Mag. for July, August and October last, articles on Glacial Erosion in the Yorkshire Dale District, in order to evoke criticism; and as no one who knows the ground has come forward to reply in detail to his arguments, I am induced to offer some notes of my own on the subject.

The cause of changes in Climate during past Geological periods having lately become, and being likely to continue, a prominent topic of interest, I have attempted here to bring together the more prominent features in the controversy, under the idea that to many readers, who have not either the time or the inclination to more closely examine the subject, this may be acceptable. In so doing I have, with one partial exception, confined myself to discussing the difficulties which beset all the various theories offered as a solution, rather than attempted the advocacy of any one of those theories in particular.

During the infancy of the “GeologicalMagazine” (1864–66), the new year was appropriately commenced with a short article on the Past and Present Aspects of Geology, or Geological Progress. As the Magazine is now entering upon its “teens”—the Third Volume of the Second Decade—and has attained an age in advance of any magazine having similar objects, it may not be out of place to return to the early plan, and commence the volume with some reflections upon the Science, which it is no flattery to state it has been one medium of advancing.

Since Sir Charles Bunbury described the Flora of Nagpúr, drawing the most rational conclusions, and since Messrs. Oldham and Morris illustrated a portion of the Flora of the Rajmahal Series in the Rajmahal Hills, nothing of importance has come before the public regarding the Flora of the Indian Plant-bearing Series, although the then abundant material has subsequently been considerably increased through the exertion of the officers of the Geological Survey of India, who have also done much to explain the geological relations of the whole Series.

Of the Swedish Graptolites up to this day but very little seems to be known in foreign countries. They merit, however, more attention than has hitherto been bestowed on them—chiefly perhaps because of the scantiness of the literature. The Graptolitic faunæ of Sweden have many analogies to those of other Silurian districts, and are therefore of great importance for the identification of the strata. An acquaintance with them is also required if one wishes to obtain a somewhat accurate knowledge of the vertical and horizontal range of the various types. A short account of them might therefore possibly have some interest even to an English geologist.

Comparatively few of the many persons who visit our larger Museums, and stop to examine the fossils exhibited in the cases, have any idea of the time, labour, care, and mechanical skill which many of them require ere they are ready for the palæontologist to interpret and describe, the artist to delineate, or made sufficiently intelligible for public exhibition. The first operation, and one requiring considerable care, is the exhumation of the fossil remains from the stratum of gravel or clay, or from the siliceous or calcareous rocks of various degrees of hardness, in which they may have been imbedded and preserved. Then the hardening of the bones—for these remarks apply more especially to the remains of the larger Vertebrata—which are generally found much broken, and, unless thoroughly mineralized, in a more or less friable and brittle condition. Next there is the fitting and cementing together of the pieces, which are frequently numerous, and of such as have been imbedded in a rocky matrix, the careful development by hammer and chisel from their incasement of stone: all of which operations necessarily involve a large amount of skilled labour.

Specific Chars.—Polyzoarium composed of small cylindrical stems occupied by oval to hexagonal cells arranged usually in quincunx; or in oblique ascending lines; periphery of the cells erect, sharp, and granular; granules minute, numerous, and closely arranged. Here and there the angles between the cells are occupied by a small supplementary pore or pores, which are occasionally increased in number, and extend vertically between two contiguous cells, or uniting, give rise to an elongated narrow groove-like slit. Section circular.

Shell very elongated, angle less than 10°, composed of eighteen or possibly more elevated, squareish whorls, which slightly diminish in convexity in descending the spire; apex acuminate (Plate IV. Fig. 4); ribs ten or eleven, straight or slightly sinuous, linear near the apex, but becoming more prominent and obtuse with the growth of the shell, the intervening spaces nearly flat. The ribs, in common with those of other Cretaceous Scalidæ, are never so clean and sharp as in the recent species, but have more the appearance of folds. In some of the larger specimens the ribs disappear altogether on the last three or four whorls, and are represented only by more or less strongly marked lines (Plate IV. Fig. 1). The striæ are fine and numerous (Plate IV. Fig. 1a), fifty or sixty on each whorl. The sutures are very distinct, the margins of the whorls being usually raised into a roll-like collar. This collar appears on the last whorl in the form of a conspicuous spiral keel, against which the ribs terminate, leaving the base of the whorl, which is very flat, marked with striæ and lines of growth only. The aperture is oval or quadrate, and in the perfect state was probably terminated anteriorly in a sort of beak (Plate IV. Figs. 2 and 3); lips thin!; columella smooth. The cast of the shell generally preserves the rib marks, except near the apex, where the whorls are smooth and very rounded.

In our last chapter we referred to the frequency of the occurrence of lakes in districts which contain volcanos that are still active or have only recently become extinct. In connexion with this subject, we must also call attention to the interesting circumstance that, wherever the geologist finds evidence of the former action of subaerial volcanos, there he almost invariably detects proofs also, that numerous lakes have been formed and successively filled up with sediments. Very strikingly is this fact illustrated among the great series of volcanic rocks, which, during a great portion of the Tertiary period, were being erupted in Central and Southern Europe; and which form an almost complete girdle surrounding, but lying at a considerable distance from, the great central masses of the Alps. We have in these districts the most unmistakable palæontological evidence that the periods of violent volcanic activity were also characterized by the repeated formation and filling up of lake-basins.

The Coprolites or phosphatic nodules of the Cambridge Greensand frequently contain amongst other included bodies a number of Foraminifera and glauconite granules, of the same kind as those found scattered loosely throughout the Greensand bed.

In the preceding chapters we have endeavoured to throw light upon some of the more salient characters of volcanos—the features of their architecture, the nature of their products, and the peculiarities of their attendant phenomena. In doing so, however, we have preferred to select our illustrations from some of the less familiar, though, as we hope to have shown, by no means less interesting volcanos of our continent; and have of set purpose avoided the oft described examples of Vesuvius, Etna, the Auvergne, and the Eifel.

Some years back the Earl of Enniskillen obtained a specimen of a fossil fish, found in the rich ichthyological treasury of the Lower Lias at Lyme Regis, which proclaimed itself at first sight to be an entirely new form, differing generically from all the previously-known fishes of the Mesozoic period.

As missiles are falling thick like hail upon Mr. Judd since his challenge to the Glacialists, I take the opportunity of putting together a few notes, made during an Alpine journey last summer, which would have been published sooner, had more time been at my disposal. The lower parts of the Gorner, Arolla, Des Bossons, Des Bois, and Argentière Glaciers were carefully studied, but others received passing attention.

Just a year ago the Academy received information that the day before there had fallen at Haga (a royal residence in the neighbourhood of Stockholm) rain mixed with snow, which brought down with it such a quantity of impurities that all the windows of the plant-house and the hot-beds there were covered with a fine grey ash-like dust.