A large portion of the last number of the Quarterly Journal of the Geological Society (February Ist) is justly devoted to the important subject of the Laurentian or oldest known stratified rocks, the elaboration and naming of which in North America were, it is well known, accomplished by Sir William Logan and his associates. On this occasion a memoir by that eminent geologist naturally leads the way, whilst, in the subsequent articles, the nature and structure of the Eozoon Canadense, which has been found in these rocks, are ably developed by Drs. Dawson, Carpenter, and Sterry Hunt.

It is often said that controversies advance science. I believe, on the contrary, that they retard it—that they are wholly mischievous, and that all good scientific work is done in silence, till done completely. For party in politics, there are some conceivable, though no tenable, reasons; but scientific controversy in its origin must be always either an effort to obscure a discovery not yet distinctly established: and it seems to me there are but two courses for a man of sense respecting disputed statements;—if the matter of them be indeed doubtful, to work at it, and put questions about it, but not argue about it; so the thing will come out in its own time, or, if it stays in, will be no stumbling-block; but if the matter of them be not doubtful, to describe the facts which prove it, and leave them for what they are worth.

Except in containing small nodules of phosphate of lime, the Chalk shows no structural change where it terminates in the Ely section, but passes down almost imperceptibly into a dark greenish layer, and rests on it at an angle of about 35°. This greenish band, scarcely a foot thick, is full of nodules of phosphate of lime, and consists largely of glauconite. It is the Upper Green-sand, with Ammonites auritus, Terebratula biplicata, Dentalium ellipticum, and the usual local features. Nowhere can the passage of one rock into another be more marked than that of the Upper Greensand of this district into the Chalk. Conditions have changed a little with physical geography, but nothing suggests any break in time. About Cambridge the section is exactly the same; the Chalk just above is often flaggy, contains a few green grains, a little phosphate of lime, and the commoner Greensand fossils mixed with those of the Chalk. Sometimes, however, there are some 10 or 12 feet of dark greyish-green marls above the Upper Greensand. They are separated by sharp lines of bedding from the Chalk, are very local, and perhaps only indicate a trifling denudation of the Gault.

The term Cambrian (from Cambria, the ancient name of Wales) was originally employed by the Rev. Professor Sedgwick to include a great series of fossiliferous and other rocks occurring below the Bala Limestone in North Wales. Sir Charles Lyell adopts to a certain extent this classification, dividing it into Upper and Lower Cambrian.

At the extremity of my sketch, fig. 1, p. 52, which by the printer's inadvertence is marked Y instead of X, the beds appear to turn suddenly downwards. They are actually more inclined at this spot; but the principle cause of their apparent increase in steepness is a change in their strike. Generally parallel to the precipice, it here turns westwards (i.e. towards the spectator); and, holding myself bound in candour to note, as I proceed, every circumstance appearing to make for the modern glacial theories, I must admit that, as the beds at this extremity of the cliff turn outwards from the Alps, it might not inaptly be concluded that the great Chamouni Glacier, which by its friction filed the mountain two thousand feet down at the top, by its pressure turned the end of it several points of the compass round at the bottom!

Small disc-shaped bodies have frequently been noticed in coal and the accompanying shales. Specimens were figured by Mr. Prestwich in 1840, in his paper on the Geology of Coalbrook Dale (Geol. Trans., Second Series, vol. v., tab. xxxviii., ff. 8, 8a); and Professor Morris, who described Mr. Prestwich's fossils, characterises them as ‘capsules’ of his Lepidodendron longibracteatum. But it does not appear from either the illustrations of the two spikes of his species, or from the letter-press, that he had found the capsules associated with the reniform thecæ of the spikes. Prof. Balfour has also figured and described similar bodies in a paper read before the Royal Society of Edinburgh in 1854. He found them in the ‘splint-coal’ of Fordel, near Inverkeithing, in Fife. He says, ‘Besides Sigillarias and Stigmarias, we also detect in the Fordel Coal peculiar rounded organisms which have the appearance of seeds. Dr. Fleming informs me that similar bodies have been observed by him in coal, and that he exhibited them to Mr. Witham about twenty years ago. They have also been seen by Dr. Fleming in Lochgelly and Arniston “parrot,” and in the coal at Boghead; and from having observed them in “cherry,” “splint,” and “cannel” coals, he is disposed to consider them as a somewhat common feature. I have seen them in coal from Miller Hill, near Dalkeith, as well as in the coalfrom Fife. They appear to be certainly allied to the fructification of the Lycopodiaceæ of the present day, more particularly to that form of it which consists of two valves placed in apposition and containing what is called Lycopode-powder. Theae and like bodies I, therefore, consider to be the sporangia or spore-cases of some plant allied to Lycopodium, perhaps Sigillaria. The valves present under the microscope a reticulated surface, and minute granular matter seems to be attached to the inner surface.’—(Edin. Trans., vol. xxi. p. 191).

A brief notice of some of the more important Rhætic Fossils in the district described in this Magazine (vol. i. p. 257) may perhaps be some guide to the identification of the beds in other British localities.

Specimens indicative of large ‘cycloid’ Fishes, with teeth of ‘sauroid’ character, have been obtained from the ‘Upper Chalk’ of England. To a species of this kind, with large circular scales covered with minute asperities visible by the aid of a pocket-lens, Agassiz assigned the generic name Pachyrhizodus, in reference to the thickness of the base of the anchylosed teeth.

Between Bishop Colenso and the volcanoes of Central France, and between these and ‘Rogation Days,’ there would at first sight seem to be but little connection. Nevertheless, a statement made by the Bishop was the cause of some curious information, which had previously been known to but few, being generally circulated; and as it then appeared only in one or two newspapers, and at different times, it may be useful to give a résumé of the controversy in a more permanent form. The Bishop, referring to Lyell (‘Elementary Geology,’ pp. 197, 198), adduced the exitstence of cones of loose scoriæ and pumice in Auvergne and Languedoc as an argument against the Noachian Deluge; because these, which ‘must have been formed ages before’ that happended, did not show the slighttest sign of having ever been disturbed. In the course of the endless controversy which has arisen from the Bishop's works, a Mr. E. L. Garbett addressed a rather angry letter to the ‘Guardian’ newspaper (Aug.24, 1864), taxing the Bishop with wilfully shutting his eyes to the fact that there had been eruptions in these districts in the fifth century, which had given rise to the ecclesiastical fasts commonly called ‘Rogation Days.’ The Bishop replied in a letter, which was refused by the ' Guardian' on account of its length, and was afterwards published in the ‘Daily News.’ However, in the ‘Guardian’ of Sept. 14, a summary of it is given, in which the following statements are made: (1) that volcanic cones do exist as above described; (2) that, according to Hoffman's ‘Lexicon,’ Rogations were instituted owing to earthquakes and to the irruption of wild beasts into Vienne; (3) that there are no volcanoes near Vienne; (4) that the authors who are supposed to describe volcanic eruptions, only speak of earthquakes and ordinary fires, or perhaps of lightning.

In our introductory observations on the past and present aspects of Geology, in No. I. of this Magazine, we alluded to some special points much discussed now-a-days, such as ‘the origin of granite, the mode of formation of river-valleys, the excavation of lake-basins, the doctrine of homotaxis, and the origin of species.’ During our six-mothes‘ existence, we have witnessed some advance in geological knowledge along these lines of research, though we cannot say that granite is much less mysterious, river-valleys and lake-basins far better understood, or the contemparaneity and succession of species more easily explained, than heretofore. Yet geologists hold a taper in the darkness—a feeble light, showing the thick mist, and but little of the footway. Along this darksome path have gone the fitting letter of the ready writer, the weightier essay, the pamphlet, and the book,—all intended to be lights or signposts, and often fit and good. Indeed many have tried to illumine this track through the history of the past; and now where do we stand, and what can we discern around us?

In the month of May, 1861, there occurred a curious subsidence of the soil in a field on the ‘Malting Farm’ at Lexden in Essex. The cavity thus produced was about twenty-five yards in circumference, of an elliptical form, and about twenty feet in depth, with the sides slightly overhanging. The subsidence took place quite suddenly; some workmen, who were in the field in the forenoon, finding the pit fresh formed on their return from dinner. The ground in which the pit is situated consists of a slightly rising bank of valley-gravel, and is about fifty yards to the south of the little River Colne, which runs past the spot, and gives its name to the ancient town of Colchester. The surface of the field cannot be more than five or six feet above the stream when full.

Though the oldest English Whales yet named are found in the Crag, Prof. Sedgwick, a quarter of a century since, obtained from Ely some anchylosed cervical vertebræ evidently Cetacean. The fossil was found at Roswell Pit in the Boulderclay, but the Professor writes, ‘I have not the shadow of a doubt that it was washed out of the Kimmeridge (or the Oxford) Clay, for both clays are near at hand. In condition it is exactly like the bones from those clays; and is utterly unlike the true Gravel bones, whether in the dry Gravel, or the Till.’* This is unmistakeable, for the specimen is mineralised with phosphate of lime; and so could have been derived from no deposit newer than the Crag.

In the number of the GeologicalMagazine for last August, in a letter from Mr. Mackintosh, there is a notice of some markings, supposed to be glacial, on a rock known as ‘The Bloody Stone’, between Cromford and Bonsall, in Derbyshire. Mr. Mackintosh's language is not very clear, but I rather gather that he has doubts whether these markings were really made by ice: nor does he seem to be aware of the great interest that would attach to the discovery, if it could be proved beyond question that we have here a true ice-marked surface of rock. It is, I believe, very generally the case that the deposits and, so to speak, footmarks of the Glacial epoch are found on the western side of the central axis of the north of England in much greater force than on the eastern side. Thus much I can say from personal observation: in North Staffordshire and Lancashire, boulder-clays and gravels are found stretching from the plains far up the hill-sides, and erratic blocks lie here and there upon the moors to a height of 1,400 feet above the sea. On the other side of the socalled Pennine Chain, however, the case is widely different: through-out the whole of North Derbyshire and the adjoining uplands of Yorkshire there is nothing that can be safely set down as Drift, and certainly no blocks or pebbles of foreign rocks over the country to the north of the Wye. The valley of that river cuts right across the Great Saddle; and along it, and to the south of it, we do find stray patches of clay with ice-scratched boulders, mostly of limestone, but here and there of granite, greenstone, and other strangers, which seem to have found their way from the west along this sole opening in the barrier which elsewhere blocked up their path. ‘The Bloody Stone’ is just a case in point, lying as it does in the valley of the Derwent, about seven miles below the junction of the Wye with thatriver. I was, therefore, extremely glad to see Mr. Mackintosh's letter just in time to pay a visit to the spot, and I shall tell as carefully as I can what I there saw, in hopes that more experienced ice-men, if they cannot go to see for themselves, may be enabled to decide whether we can fairly refer the markings in question to the action of ice.

In my observations on the Laurentian Rocks of Birtain which appeared in the last number of the Geological Magazine, there is one statement which calls for midification, and another which I revoke. The striking discordance of direction or strike between the true Laurentian rocks of the North-Western Highlands and Islands, and the superficial strata of Cambrian and Lower Silurian age as described by me, is undoubtedly correct; but in another paragraph it is inadvertently said that the Silurian rocks of Britain trend everywhere from NE. to SW. For ‘everywhere’ the word ‘usually’ should have been employed, as there are tracrs wherein these rocks unquestionably range from W. to E.

The specimen of Fossil Wood in flint, figured in Pl. IX. of the Geological Magazine, from a drawing by Mr. Crozier, was presented to the Oxford Museum by Sir Woodbine Parish, K.C.H., to whose intelligent liberality the public collections of England are greatly indebted. It was obtained from the Chalk of Winchester.

I have lately received, from Mr. James Armstrong of Glasgow, some very beautiful examples of the detached teeth of Dithyrocaris from Lanarkshire and Renfrewshire, and also specimens of Ceratiocaris from Lesmahagow (the latter collected by Mr. J. Slimon); and they seem to possess so much interest, that a description of them will doubtless be welcome.

The Upper Greensand is a marine formation. Dr.Fitton, in his elaborate Memoir on ‘The Strata below the Chalk‘ (Geol.Trans., Second Series, Vol. IV.), has enumerated 60 species of Mollusca, 2 Annelids, 3Echinoderms, and 2 Protozoons from the beds in the South of England belonging to this period. These numbers have been more than doubled since the publication of that paper. They still retain the same proportions; but the fossils which Dr. Fitton characterised as ‘ fish remains ’ have been referred to 9 genera, and there have been added 4 genera of Saurians. As might be expected, very few vegetable remains have been observed. Dr. Fitton records the occurrence of some impressions of leaves. The remains of what appear to be sea-weeds are occasionally met with. Specimens of fossil wood have also been found. William Cunnington, Esq. F.G.S., of Devizes, who has kindly, through the Editor, furnished me with some particulars regarding the Upper Greensand deposits near Shaftesbury, informs me that for forty years he has been collecting the fossils of these beds, and that during that time he has obtained about thirty specimens of woods, many of them certainly drift woods, as they had been attacked by lithophagous molluscs. I have examined all the specimens of these woods contained in the collections of the British Museum, and I find that they are all Coniferous. Little more than this can be said. The woody fibres contain a single row of discs, and I have not detected any spiral fibres associated with them.

The two Memoirs by Dr. Reynès, on the Cretaceous formation, which were noticed in the ninth number of the Geological Magazine, suggest two questions: how far subdivisions there proposed are applicable to the Cretaceous series of this country; and, next, as to the sufficiency of the ground on which the synchronism of the subdivisions of geological formations has been based. The subject of the second Memoir, ‘De l'Étage,’ involves considerations which might be well extended to the whole range of the geological series: indeed, it will hardly be profitable to make much progress with the past physical history of the earth until rules for determining geological horizons shall be established.