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instead of 154, or 7 per cent. less. A similar, but generally less correction, may be required for other stations. The figures in Table V. must not therefore be considered as showing the mean fall at the several stations, but only as approximations generally pretty close. The data in our possession, if corrected in accordance with the method explained, would afford more accurate results, but the investigation is altogether beyond our present resources.

Large tracts of Ireland, and even of Scotland, are still without observers ; much has recently been done to remedy these deficiencies, but there are still many localities where observations are very much wanted; we shall gladly receive

any offers of assistance from those who have residences or property in those parts, and our Secretary will readily advise them as to instruments.

Third Report on the British Fossil Corals. By P. MARTIN DUNCAN,

F.R.S., F.G.S., Professor of Geology in King's College, London. Introduction.—There can be no doubt that the palæontology of the Madreporaria of the Palæozoic strata is in a condition of profound confusion. When these Reports were commenced, the very excellent descriptions and classification of the Palæozoic Corals by MM. Milne-Edwards and Jules Haime, strengthened by those of M. de Fromentel, appeared to have satisfied paläontologists, and they were received and adopted without much demur. But during the last three or four years a series of more or less important attacks has been made upon the views of those distinguished authors; consequently opinions respecting many important matters in the palæontology of the Palæozoic corals are in a very unsatisfactory state.

L. Agassiz, A. Agassiz, and now Count Pourtales would remove the Tabulata from the list of Madreporaria. Mr. Kent and I doubt the propriety of establishing the Tabulata as a group. Count Keyserling demurred years since at receiving the long septaless Tubulata amongst the Madreporaria, and, after due examination, I agree with him in relegating them to the Alcyonaria.

Working amongst the Rugosa, I have shown that they do not invariably characterize Palæozoic strata, for some of the types have persisted, and no reasonable doubt can be entertained concerning the descent of the Jurassic Coral-fauna from the Palæozoic.

The genus Palæocyclus has been shown not to belong to the Fungidæ, but to the Cyathophyllidæ. Genera with the hexameral arrangement of septa have been found in Carboniferous and Devonian strata.

Lindström's interesting researches respecting the operculated condition of some Palæozoic corals require most careful study and much following up, and the assertion of L. Agassiz respecting the hydroid relationship of those Rugosa which have tabulæ demands further inquiry

Ludwig, of Darmstadt, has added to the confusion by not acknowledging the received classification in the least; and in his able enthusiasm (anti

* G. Lindström, pamphlet translated by M. Lindström from the original Swedish, "Geological Magazine,' 1866, p. 356. He notices that Guettard first described an operculum in a rugose coral, and that then Steenstrup saw one in a Cyathophyllum mitratum. Lindström produces evidence respecting the genera Goniophylluin, Calceola, Zaphrentis, Hallia, and Favosites (see also p. 406 et seq.).

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Gallican enough) he alters generic and specific names, employing sesquipedalian Greek, and even absorbing the original authors (* Palæontographica,' H. von Meyer, 1866).

Thus he confuses Stromatopora concentrica, Goldfuss, with the Madreporaria, and calls it Lioplacocyathus concentricus. Fortunately Ludwig gives a plate of it (tab. lxxii. fig. 1), and thus proves the total absence of all structures which differentiate the Madreporaria. After thus dignifying a rhizopod, we may be prepared for any thing.

The same author figures a form which is clearly that of Heliolites porosa, and calls it by the extraordinary name of Astroplacocyathus solidus, Ldwg. It appears that this naturalist studied this eminently cellular type from a cast, hence the term solidus. Again, in tab. lxxi. fig. 2, Ludwig delineates a good specimen of Cyathophyllum hexagonum, Goldfuss, 1826, and with surpassing coolness names it Astrophloeothylacus vulgaris, Luwg. He then confounds a species of Lithostrotion and Smithia Hennali, E. & H., in one genus, Astrophloeocyclus, Ldwg.

The student of the Silurian corals will be surprised perhaps to find that, according to Ludwig, Halysites catenularia, Ed. & H., the Catenipora escharoides of Lonsdale, is transformed into Ptychophlcolopas catenularia, Ludwig, doubtless on the principle that having found such a very distinguished generic title, the compiler of it has the right to eclipse the discoverers of the form. Chatetes, which some of us consider to belong to the Alcyonarian group, as it has no septa, Ludwig decorates with the title “Liophloeocyathus."

In his sixty-ninth plate, fig. 5, there is a very good representation of a coral ordinarily known as Acervularia Troscheli, Ed. & H. This form was inaccurately described by Goldfuss, who called it Cyathophyllum ananas. Now the authorship is settled by this Alexander, who cuts the knot by claiming the species as his own, under the title of Astrochartodiscus ananas, Ludwig !

Then Pleurodictyum problematicum, Goldfuss, is altered into Tæniochartocyclus planus, Ldwg.

To render matters easier to the student, Ludwig associates Acervularia luxurians and Cyathophyllum helianthoides in one genus, Astroblascodiscus, and of course places his name after the species. Then Cyathophyllum cæspitosum becomes, under the same lexicographic hands, Astrocalanocyathus cespitosus, Ludwig! In another place Cyathophyllum helianthoides, Goldfuss, just mentioned under the term Astroblascodiscus, appears as Astrodiscus. Lonsdale's Cystiphyllum cylindricum is turned into Liocyathus catinifer, Ldwg.

This author, moreover, appears to hold a brief against the belief in the quadrate arrangement of the septa in the Rugosa, and, in a manner which is excessively arbitrary and artificial, terms such and such septa primaries, so as to reduce the cycles to sixes. In spite of the evidence of great industry given by Ludwig, I cannot accept his classification, nor do I find his hypothetical septal readings consistent with facts. Nevertheless, Ludwig has contributed to our knowledge of Permian corals, and has discovered some species of genera hitherto supposed to characterize the Carboniferous formation in the Upper Devonian of Germany.

The nature of this Report must therefore be very different to those already presented to the Association. Those reports relating to the Corals of the Mesozoic strata were essentially founded upon observed facts, and upon

data which had been more or less before the geological world for years; the generalizations embodied in them were established upon very satisfactory details. But in the present instance there is much uncertainty; there are

upon them.

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vast accumulations of details to be worked out without the existence of a satisfactory classification, and, in fact, the whole subject of the Palæozoic Madreporaria is in too transitional a state for an exhaustive report to be made

In presenting this Report, therefore, I hope the Association will consider that I have not yet completed my task, and that it will allow me to continue my work and to present other reports when occasion offers. No further grant will be required, as the future reports will deal more with the results of other labourers than with my own.

The present Report is divided into four parts.

I. The consideration of the alliances of the Neozoic and the Palæozoic Coral-faunas.

II. The classification of the Perforata.
III. The classification of the Tabulata.
IV. The Rugosa.

In order to avoid useless repetition of well-known facts, I have referred to them by giving their bibliography, except when they are contained in inaccessible works.

I. The Palæozoic corals of Great Britain have been the subject of many admirable works; they have been largely treated of in the • Monograph of the British Fossil Corals' (Palæontographical Society) by MM. Milne-Edwards and Jules Haime, and by M.Coy in Sedgwick's great work. Phillips, Lonsdale, King, Sam. Woodward, Parkinson, Martin, Fleming, Portlock, Sowerby, and Pennant have described species in their well-known works, and Kent, James Thomson, and I have contributed some information on the subject of the Scottish corals. But, with the exception of the labours of the last three persons, the literature of the Palæozoic Corals will be found very accessible in the monograph already noticed ; any omissions, and a considerable number of new species will be published in my Supplement to that monograph, which I trust will appear year after year, especially as the Supplement to the Mesozoic Corals is now complete (Palæontographical Society).

The vertical range and the horizontal distribution of the species of corals have been worked out by Robert Etheridge, F.R.S., in a work which is now in course of publication (Cat. of Brit. Fossils),

MM. Milne-Edwards and Jules Haime classified the British Palæozoic Corals amongst the sections Aporosa, Tabulata, Tubulosa, and Rugosa. The great section Perforata is not represented in the British strata, but it is in the equivalent American beds.

The only representative of the Aporosa in their classification was one of the Fungidæ, Palæocyclus being the genus. It is a Silurian form, and no others of the family have been discovered in the other Palæozoic rocks. The genus has been the subject of a memoir in the Philosophical Transactions, 1867, where its rugose affinities are pointed out, and its cyathophylloid nature also. But the Aporosa are nevertheless represented in the Devonian and Carboniferous rocks by the genera Battersbyia and Heterophyllia (Phil. Trans. 1867).

The alliances of these forms and of some of the Rugosa with the Jurassic Coral-fauna have been noticed in my Supplement to the Brit. Foss. Corals (Pal. Soc.), part “Liassic,” and in the Essay in the Phil. Trans. of 1867*.

* The PalastRÆACEÆ. Genera Battersbyia and Heterophyllia (Phil. Trans. 1867, p. 643 et seq., P. M. Duncan):--The so-called cænenchyma of Battersbyia inæqualis, Ed. & H., is like that of Battersbyia grandis, nobis, and B. gemmans, nobis. It is really nothing

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I do not consider that the Tubulosa belonged to the Madreporaria, but that they were Alcyonarians.

It is very certain that some Aporose, Perforate, and Rugose corals have tabulæ, and that their existence cannot remove the forms from their received zoological position into the separate section of Tabulata.

Thus the well-known Aporose coral of the deep sea, Lophohelia pro

more than portions of Stromatopora which enclose the corallites and

grow

simultaneously with them.

I have altered the generic characters of Battersbyia, in consequence of a careful examination of the old and the two new species. It is as follows:--Corallum fasciculate and branching; corallites tall, cylindrical, unequal in size and distance; septa numerous and following no apparent cyclical order.

Endotheca very abundant: it is vesicular, and there are no tabulæ. Epitheca, costæ, and canenchyma wanting. The wall is stout, and the septa spring from wedgo-shaped processes. The columellary space is occupied by vesicular endotheca. Gemmation extracalicular and calicular from buds having only five septa. There are three species :

Battersbyia inæqualis, Duncan.) Deronian Limestone ;
grandis, Duncan.

found in pebbles,
- gemmans, Duncan.

and not in situ. In Battersbyia gemmans the buds which develop more than five septa grow into corallites, which are destined to bud again from the external wall, and the buds which develop five septa produce other buds from their interseptal loculi; the buds thus developed resemble the corallites with more than three septa. This curious alternation of gemmation has not been noticed in any other genus.

The genera Battersbyia and Heterophyllia (Phil. Trans. loc. cit.) have much in common. They have a stout wall, a vesicular and dissepimental endotheca, delicate septa, very irregular in their number, and neither tabular epitheca nor a quaternary septal arrangement.

The genus Battersbyia has nothing to ally it to the Rugosa or the Tabulata. Hetero-. phyllia has in some of its species the solitary septum or vacancy which is so often observed in the Cyathophyllida. Its costal wall and endotheca connect it with the Mesozoic and revent Astræida

The singular septal development of Battersbyia is witnessed in the fasciculate Liassic Astræidæ. The pentameral arrangement of the Battersbyian sepia is not unique, for Acanthocænia Rathieri, D'Orb., of the Neocomian has only five septa, and so have the species of Pentacænia, all of which are from the same great formation. The proper Liassic and some of the Lower Oolitic Thecosmiliæ and Calamophylliæ represent and are allied by structure to Battersbyia. The highly specialized characters of the Heterophylliæ, especially of H. mirabilis, could hardly be perpetuated during great and prolonged emigrations, so that the genus appears to be without representatives in the secondary rocks. Its alliance to Battersbyia, however, is evident enough.

The genus Heterophyllia, M'Coy, was examined by me in 1867, and the study of several new species of it rendered a fresh diagnosis requisite.

The following description of the diagnosis appeared in my essay on the genera Heterophyllia, &c., already noticed :

** The corallum is simple, long, and slender. The gemmation takes place around the calicular margin, and is extracalicular. The septa are either irregular in number and arrangement, or else are six in number and regular. The costa are well developed, and may be trabecular, spined, and flexuous. The wall is thick; there is no epitheca, and the endotheca is dissepimental.”

The genus may be subdivided into a group with numerous septa, and a group with six septa.

In the first the rugose type is faintly, and in the last the hexameral arrangement is well observed.

The dense wall and the dissepimental endotheca prove that the type of the Mesozoic Coral-fauna was foreshown.

The endotheca varies in quantity in the different species, and it resembles the tabular arrangement; but even when this is the case and the cross structures are well developed and numerous, they do not stretch over the axial space, so as to shut out cavities as if they were floors ; they do not close in the whole of the visceral and interlocular

lifera, Pallas, sp., may have some of its corallites subdivided by perfect tabulæ ; the species of Cyathophora of the Colites also; yet it would be a most objectionable and improper proceeding to remove these genera from their recognized alliances. I found an Astræopora in the Museum at Liverpool with tabulæ ; and Mr. Kent has pointed out the perforate affinities of Koninckia and of the form he has published. Some Rugosæ have perfect tabulæ, others have them not; and in Cyclophyllum and Clisiophyllum dissepiments exist in some parts of a corallum and not in others, where they are replaced by tabulæ. This interesting fact may be gleaned from James Thomson's sections taken from the Scottish corals.

Nevertheless there are forms which are essentially tabulate, and not rugose, but which, so far as their hard and septal structures are concerned, may be aporose in one instance and perforate in another; for instance, Columnaria and Favosites. These forms may still provisionally be considered Tabulata.

Alliances.—The Lower Cretaceous and Neocomian corals appear to connect the oldest and the newest faunas, and to form an excellent starting-point both for the study of the Tertiary as well as for the Palæozoic forms. It will be readily observed that the succession of genera and species from the lower Cretaceous horizon to the present day is gradual; and that although many forms died out, still the general appearance of the consecutive faunas, such as those of the Middle and Upper Cretaceous, the Nummulitic, the Oligocene, the Miocene, the Pliocene, and of the two great faunas of the present day, presents a remarkable similarity of what is usually called “facies." The similarity between the Lower Cretaceous fauna and that of the Miocene has been treated of elsewhere *, and the analogies of the mid-tertiary corals and those of the Pacific also. Moreover since the last Report was read the distinction between reef, deep-sea, and littoral corals has been more satisfac'torily established, and the reason why consecutive faunas upon the same areas could not possibly be identical, even as regards the genera, has been explained t.

As the Coral-faunas are studied from those of recent date backwards in time, extinct forms are met with which gradually fill up the spaces in the very natural received classification, and it is perfectly evident that the existing species were foreshadowed in the past. A great number of existing species lived in the so-called Pliocene, and not a few in the Miocene I. Reuss's admirable researches amongst the vast reefs which are of an intermediate age between the Flysch and the typical coral districts of the Miocene age, hare carried back the homotaxis of the existing coral areas to a time which has hardly been recognized by British geologists, but whosc fossils are clearly

cavities in a horizontal plane. In some species the dissepiments are curved, and are as incomplete as when they are more or less horizontal in others, and vesicular endotheca exists, more or less, in nearly all the forms.

There are no true tabulæ, and the dissepiments do not interfere in any way with the passage of the septa from the lowest part of the corallum to the calice. There are eight species of Heterophyllia :Heterophyllia grandis, M'Coy.

Heterophyllia M Coyi, Duncan. ornata, M.Coy.

Lyelli, Duncan. granulata, Duncan.

mirabilis, Duncan. angulata, Duncan.

Sedgwicki, Duncan. The first two are found in the Carboniferous limestone of Derbyshire, and the others in the Scottish Carboniferous strata (see Pbil. Trans. 1867, p. 643 et seq.). * West-Indian Foss. Corals (P. M. Duncan, Quart. Journ. Geol. Soc. xxiv. p. 28).

p. + Coral Faunas of Europe (Quart. Journ.

Geol. Soc. xxvi. p. 51 et seq.). 1 Corals of Porcupine Expedition (Proc. Royal Society, xviii. p. 289).

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