Agassiz, after describing the intermaxillary bone of Megalichthys, makes the following brief statement regarding the fossil which is the subject of the present paper: “M. König possède une pièce detachée qui parait etre le même os.”

The ore which is the subject of this paper occurs in rather an uncommon manner; its existence, however, has been known for a very considerable period, and it is said to have been worked at least 250 years ago. I believe it is this that is referred to in Dr. Boate's quaint work,“Ireland's Naturell History,” as being found “by the side of the rivulet Lishan, not far from Lough Neagh,”—although he classes it with the ordinary clay-ironstones, which it certainly does not resemble either in composition or appearance.

The article by Mr. Clifton Ward upon “Rock Fissures” in the GeologicalMagazine for June, has reminded me of a special characteristic of some igneous rocks, which has been perhaps as yet imperfectly appreciated. I mean by igneous rocks, such masses of subterranean, mineral matter as have apparently thrust themselves upwards to the surface of the globe by a process of internal expansion or intumescence, caused by heat —not always attaining absolute fusion, but in some degree owing to the general permeation of the matter by super-heated water, or steam, or other gases.

Many Geologists will hail with satisfaction the accession of Prof. Hull to the ranks of the few who appreciate the importance of a microscopic examination of rocks; and the communication from him which appeared in the last Number of the GeologicalMagazine is the more welcome, as it contains a promise of further researches in the same direction.

Every one who has traversed our Chalk Downs must have noticed here and there shapeless masses of grey stones, half buried in the turf. Sometimes they are found in groups, like the shattered ruins of some ancient temple, and at other times they occur in isolated blocks, as though giant hands had hurled them at random over the hills in wanton sport. At one place, near the village of Kennet, they assume the appearance of a multitudinous flock of sheep, and are known by the appropriate designation of “Grey Wethers,” whilst at other places in the same vicinity they bristle on the hill-sides, and trail along the valleys like the débris of an avalanche or the moraine of a glacier. Nowhere do they exist in such profusion as on the west of Marlborough, but they are found scattered over the whole Chalk area of this district. At the western end of it they consist chiefly of saccharoid sandstone. Further east, especially around Newbury, they become smaller, harder, and more crystalline; whilst in the neighbourhood of Great Bedwyn, and occasionally elsewhere, they take the form of pudding-stone, being agglomerations of flint pebbles, cemented together in a matrix of siliceous sand.

The accompanying analytical Table of the genera of the Rhabdophora which are especially treated of in the present paper is here offered as a first and suggestive sketch for an improved arrangement of these forms. The foregoing conclusions have been employed in its construction, and are embodied in the general scheme.

Some time since, I read before the Geological Society of Glasgow a paper on “The Valley of Loch Lomond,” and pointed out that the deeps and shallows corresponded with, the faults and breaks in the adjoining country. This paper was quoted by His Grace the Duke of Argyll, President of the London Geological Society, in opposition to the view (so ably advocated by Professor Ramsay) that ice has been the principal, if not the only, agent engaged in the formation of such hollows.

Dr. Macalister, in his able Presidential Address, has furnished the Society with a summary of the work done, principally by German petrologists, with the object of determining the mineral constitution and structure of plutonic, metamorphic, volcanic, and other rocks, by the aid of the microscope. Forbes, Sorby, and Allport amongst ourselves have also represented British petrologists in the same field, but perhaps have not been sufficiently forward in giving the results of their labours to the world.

The subject of Captain Hutton's lecture, on the Formation of Mountains, delivered at Wellington, New Zealand, is one which has engaged a good deal of my attention, and was discussed by me in a paper read before the Cambridge Philosophical Society, and printed in their Transactions. In that paper I attributed the elevating force, which has raised mountain ranges, to the contraction of the heated interior of the earth, and subsequent wrinkling of the crust so as to accommodate itself to the diminished nucleus. This was an old hypothesis, but I believe the amount of horizontal pressure produced in that manner had not been estimated before. Mr. Mallet, the eminent seismologist, read a paper on the same subject before the Royal Society in May, 1872, in ignorance of what I had written, and came to the same conclusion as myself as to the amount of the horizontal pressure.

The Geology of Dorset presents an almost consecutive series of formations from the Liassic to the Quaternary. The Rhætic beds which have so large a development in the neighbouring counties of Somerset and Gloucester, just touch the confines of the county near Lyme Regis, and were described by Mr. H.W. Bristow, F.R.S., Director of the Government Geological Survey, at the Bath Meeting of the British Association in 1864, as everywhere underlying the true Liassic strata.

The genus Conularia was first described by Miller about the year 1820, and afterwards more fully by Sowerby, as a “conical hollow univalve shell,” (Min. Con., vol. iii. p. 107). It had previously been figured by Ure under the name of a “curious fossil” (History of Rutherglen and E. Kilbride, p. 330). Sowerby, amongst other characters, noticed that in one of his specimens, formerly in Miller's collection, the edges or “lips” of the broader or truncated end of the shell were inflected, and nearly met in the centre (l. c. t. 260, fig. 4).

Calceola sandalina, both by its generic and specific name, means a little shoe or slipper. It is a common fossil in the Devonian rocks of the Eifel and other continental localities, and was found years ago by Mr. Godwin-Austen at Ogwell, near Chircombe Bridge, in Devonshire.

In compiling for the Census Bureau of the United States a small geological map, I had occasion to determine the precise areas occupied by workable beds of Carboniferous Coal. As the sum total is different from that recently stated in the GeologicalMagazine, I have thought a correction desirable; and present a few statements, based upon original authorities, the best within my reach.

As the sands and clays of the Hastings series lie conformably on the Purbeck Beds, it is probable that the same area which formed the embouchure of the Purbeck river performed still the same office during the Hastings Sand age; but the entirely different character of the deposit shows at least that the soil of the country drained by the latter was different from that which supplied the former; and it is evident also that, in the district under consideration, the motion of the water of the Hastings river was much more rapid, from the abundance of sand, coarse quartz, and gravel with pebbles.

In the July Number of the GeologicalMagazine, I described certain new species of bivalve Mollusca from the Carboniferous series of Scotland. These will now be found on Plate XII., accompanied by three other well-marked forms from the same formation, and which appear to me to be undescribed. In Messrs. Young and Armstrong's Catalogue of the Carboniferous Fossils of the West of Scotland is recorded a new species of Pteronites, under the specific name of P. fluctuosus (Etheridge, MS.), a shell so named by my father, but never yet described. P. fluctuosus is specifically remarkable for its small size, and the absence of ribs on the anterior side.

Fifteen years ago scarcely any attention had been paid to the subject of the earliest evidences of human antiquity in Western Europe.

I had hoped that ere this some one better acquainted than myself with Irish post-Tertiary Geology would have collected into one memoir the details scattered throughout the various scientific journals, thus enabling English geologists to compare the later deposits of Britain with those of the sister-kingdom. Since no one has done so, I venture to put some notes of my own upon the subject before the readers of the GeologicalMagazine, especially as, in some recent discussions upon the Irish drift, “Palæontological succession” has not received the consideration it may fairly claim.

The Lamellibranchiata of the Scotch Carboniferous beds appear to agree on the whole tolerably well with those of the series as developed further south, notwithstanding we here and there meet with well-marked varieties, and occasionally new species. These are not so numerous as might have been expected when we take into consideration the very different physical conditions which must have existed during the deposition of the series in the two areas.

It must be admitted that if during the Glacial period an arctic current, similar to that which now sweeps along the east coast of North America, were to pass over the submerged portions of our island, there is no reason why the climate of this country should not assimilate to that of Labrador, where there is now perpetual frozen ground in the latitude of Liverpool. The question then is, what evidence have we that such a current existed at the commencement of the Glacial epoch ? Have we not the evidence of the striæ on the rocks and mountains of the Scandinavian peninsula, as well as on those of our own country, to show that, during the period of the submergence of these districts, icebergs were driven by an arctic current from the north-east to the south-west ?—that the Polar Sea extended from the White Sea to the entrance of the Baltic, spreading southward over Germany to the confines of Switzerland, which can be traced by the deposited boulders and other ice-transported materials ? Then, as to the cause of this return current. It must be evident that the Gulf-stream at that date could not have flowed in its present direction. The arctic current coming down the Baltic must have thrown it further to the west, so that in all probability in its northern progress it would impinge on the east coast of Greenland and the Island of Spitzbergen; then being deflected by the polar ice, it would return by the way of the White Sea and the Baltic, so completing the circuit.

During several years I have had frequent opportunities, in my spare time, of collecting and studying the Crinoidea, particularly those of the Carboniferous formation; bat I have not had time, nor do I feel competent, to treat this subject fully in all its bearings. Perhaps, however, a few further notes on what I have observed in connexion with them, and in their relations with the recent as well as with those found in the several geological formations, may have an interest for some of your readers, or may be suggestive of further examination by some one better qualified, by physiological knowledge, for the inquiry.